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Behaviour of the major resin- and fatty acids of slash pine (Pinus elliottii) during organosolv pulping Quinde Abad, Augusto 1990

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BEHAVIOUR OF THE MAJOR RESIN- AND FATTY ACIDS OF SLASH PINE (PINUS ELLIOTTII) DURING ORGANOSOLV PULPING BY AUGUSTO QUINDE ABAD B . S c , N a t i o n a l A g r a r i a n U n i v e r s i t y (Lima-Peru), 1973 M.Sc, State U n i v e r s i t y of New York, 1981 A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS OF THE DEGREE OF DOCTOR OF PHILOSOPHY i n THE FACULTY OF GRADUATE STUDIES (F a c u l t y of F o r e s t r y ) (Department of F o r e s t H a r v e s t i n g and Wood Science) We accept t h i s t h e s i s as conforming to the r e q u i r e d standard THE UNIVERSITY OF BRITISH COLUMBIA September, 1990 © Augusto Quinde Abad, 19 90 In presenting this thesis in partial fulfilment of the requirements for an advanced degree at the University of British Columbia, 1 agree that the Library shall make it freely available for reference and study. I further agree that permission for extensive copying of this thesis for scholarly purposes may be granted by the head of my department or by his or her representatives. It is understood that copying or publication of this thesis for financial gain shall not be allowed without my written permission. Department The University of British Columbia Vancouver, Canada Date t k 6 U r / / j g g o DE-6 (2/88) ABSTRACT A h i g h e x t r a c t i v e - c o n t e n t t e m p e r a t e c o n i f e r wood {Pinus e l l i o t t i i ) was e x a m i n e d as a p u l p w o o d s o u r c e by o r g a n o s o l v p u l p i n g . P a r t i c u l a r l y , t h e b e h a v i o r o f t h e r e s i n - a n d f a t t y a c i d s d u r i n g t h e l i g n i n s o l v o l y s i s p r o c e s s was s t u d i e d i n d e t a i l . F o r t h i s p u r p o s e t h e r e s i n -a n d f a t t y a c i d s were c h a r a c t e r i z e d i n t h e wood, a n d a f t e r p u l p i n g t r i a l s i n o r d e r t o r e v e a l t h e i r f a t e d u r i n g p u l p i n g , u s i n g c a t a l y z e d 8 0 % a q u e o u s a l c o h o l ( m e t h a n o l ) as s o l v e n t . Wood e x t r a c t i v e s w e re r e m o v e d by b o t h m e t h a n o l i c c o l d m a c e r a t i o n a n d S o x h l e t e x t r a c t i o n t e c h n i q u e s . The r e s i n -a n d f a t t y a c i d f r a c t i o n s t h u s c o l l e c t e d w e re s a p o n i f i e d a n d / o r m e t h y l a t e d a n d c h a r a c t e r i z e d b y g a s l i q u i d c h r o m a t o g r a p h y (GC) a n d g a s c h r o m a t o g r a p h y - m a s s s p e c t r o m e t r y (GC-MS). No s i g n i f i c a n t d i f f e r e n c e s were f o u n d i n r e g a r d t o e x t r a c t i o n e f f i c i e n c i e s b e t w e e n t h e two t y p e s o f c o l d e x t r a c t i o n s . F u r t h e r m o r e , t h e r e was no s i g n i f i c a n t d i f f e r e n c e b e t w e e n t h e s e two t y p e s o f c o l d e x t r a c t i o n s i n c o m p a r i s o n w i t h t h e p r o c e d u r e d e s c r i b e d b y T A P P I s t a n d a r d T 204 o s - 7 6 . P u l p i n g e x p e r i m e n t s w ere p e r f o r m e d a t 2 0 5 2 C f o r p e r i o d s o f 5, 20, 40, a n d 60 m i n . L i g n i n s , w h i c h i i i p r e c i p i t a t e d on cooling of the black li q u o r (Lignin f r a c t i o n I ) , were set aside for further extractions and chemical analyses. The molecular weight d i s t r i b u t i o n of these l i g n i n s was determined by size exclusion chromatography on an HPLC and t h e i r quantity was determined either gravimetrically or volumetrically. P r e c i p i t a t e d Lignin Fraction I, suspected of containing some adsorbed extractives and some f i b e r fragments, was transferred to a tared c r u c i b l e . The l i g n i n and extractives were sequentially dissolved by using tetrahydrofuran (THF), acetone and methanol. This solution was evaporated, the residue redissolved i n methanol-water (80:20) and the solution l i q u i d - l i q u i d extracted with d i e t h y l ether i n a separatory funnel followed by methylation p r i o r to GC and GC-MS analysis. Quantification of the r e s i n - and f a t t y acids i n the wood and those recovered af t e r organosolv pulping was performed using an in t e r n a l standard (methyl heptadecanoate) added p r i o r to the extraction steps. The extractives dissolved i n the black li q u o r were i s o l a t e d by a ternary l i q u i d - l i q u i d extraction scheme using d i e t h y l ether, methylated with fresh diazomethane, and the r e s i n - and fa t t y acids methyl esters characterized by GC and GC-MS. The extractives present i n the pulp were i v i s o l a t e d (removed) by a Soxhlet e x t r a c t i o n procedure with methanol and" the r e s i n - and f a t t y a c i d s f r a c t i o n s c h a r a c t e r i z e d as above. R e s i n - and f a t t y a c i d s s u r v i v i n g the high-temperature p u l p i n g process, were found mainly i n the b l a c k l i q u o r . A f t e r the 60 min cook, the b l a c k l i q u o r c o n t a i n e d 78.1% and 71.6% of r e s i n - and f a t t y a c i d s , r e s p e c t i v e l y , while the p u lp r e t a i n e d 11.7% and 8.2%, r e s p e c t i v e l y of the e x t r a c t i v e s o r i g i n a l l y p r e s e n t i n wood. " L i g n i n f r a c t i o n I" adsorbed 10.2% and 20.2% of the r e s i n - and f a t t y a c i d s , r e s p e c t i v e l y . C o n t r a r i l y , i f a l l of the l i g n i n i s p r e c i p i t a t e d ( L i g n i n f r a c t i o n II). p r i o r t o l i q u i d / l i q u i d e x t r a c t i o n of the b l a c k l i q u o r with d i e t h y l ether, 98% and 60.4% of the r e s i n - and f a t t y a c i d s c o - p r e c i p i t a t e with the l i g n i n and 2.0% and 39.6%, r e s p e c t i v e l y , remain d i s s o l v e d i n the aqueous f i l t r a t e . I n d u s t r i a l organosolv l i g n i n i s o l a t e d a f t e r s o l v e n t p u l p i n g of p i n e was thus shown to c o n t a i n most (98%) of the r e s i n a c i d s and 39.6% of the f a t t y a c i d s normally found i n p i n e s . Although not t e s t e d , i t i s supposed t h a t l i g n i n s i s o l a t e d by p r e c i p i t a t i o n from the b l a c k l i q u o r a f t e r organosolv p u l p i n g of other s p e c i e s cannot be c o n s i d e r e d as " p r i s t i n e l i g n i n s " as d e s c r i b e d h i t h e r t o i n the t e c h n i c a l l i t e r a t u r e , s i n c e such l i g n i n s are h e a v i l y contaminated by the e x t r a c t i v e s of the wood s p e c i e s . In l i g h t of these f i n d i n g s a l l data on chemical and p h y s i c a l c h a r a c t e r i z a t i o n of organosolv l i g n i n s and t h e i r r e a c t i v i t y w i l l have to be reexamined and reassessed remove the e f f e c t of the extractives as contaminants. v i TABLE OF CONTENTS ABSTRACT i i TABLE OF CONTENTS v i LIST OF FIGURES x i LIST OF TABLES xiv ACKNOWLEDGEMENTS x v i i ABBREVIATIONS xix 1. INTRODUCTION 1 2. LITERATURE REVIEW 5 2.1. Wood Extractives 5 2.1.1. Background 5 2.2. Chemical Composition of Wood Extractives 7 2.3. Organosolv Pulping 10 2.4. E f f e c t s of Wood Extractives on Pulping 15 2.5. Resin- and Fatty Acids 20 2.5.1. Background 2 0 2.5.2. Chemical Analysis of Resin- and Fatty Acids 23 2.5.3. Resin- and Fatty Acid Characterization i n Wood and Black Liquor 26 2.5.4. Characterization of Resin- and Fatty Acids i n Pulp and Paper M i l l Effluents . . .39 2.6. U t i l i z a t i o n of Extractives 44 3 . METHODOLOGY ..49 3.1. Sample C o l l e c t i o n and Preparation 4 9 3.2. Chemical Analysis of Wood 49 3.2.1. Wood extractives determination 50 3.2.1.1. Cold methanol maceration 50 v i i 3.2.1.2. Methanol Soxhlet extraction 51 3.2.1.3. Ethanol-benzene Soxhlet extraction 51 3.2.2. Acid-insoluble l i g n i n 51 3.2.3. Acid-soluble l i g n i n 52 3.3. Preliminary Studies for the Characterization of Resin- and Fatty Acids 53 3.3.1. Gas chromatographic studies 53 3.3.1.1. Methylation of r e s i n - and fa t t y acids 54 3.3.1.1.1. Time of methylation reaction 57 3.3.1.1.2. Solvent s e l e c t i o n for methylation .60 3.3.2. Saponification of e s t e r i f i e d f a t t y acids 60 3.4. Characterization of Resin- and Fatty Acids from Wood 61 3.4.1. Gas chromatographic analysis 61 3.4.2. Preparation of c a l i b r a t i o n curve 63 3.4.3. Gas chomatography-mass spectrometry (GC-MS) 64 3.5. Organosolv pulping of slash pine 64 3.5.1. Pulping conditions 65 3.5.2. High pressure organosolv pulping 66 3.5.2.1. Resin- and f a t t y acid removal and characterization from the black li q u o r 69 3.5.2.1.1. Liquid-Liquid Extraction 70 v i i i 3.5.2.1.2. E f f i c i e n c y of the l i q u i d - l i q u i d extraction 73 3.5.2.1.3. Quantification of the r e s i n and fa t t y acids i n the black l i q u o r 74 3.5.2.2. Resin- and f a t t y acids removal from l i g n i n 75 3.5.2.3. Resin- and fa t t y acids removal from pulp 75 3.5.2.4. Complementary analysis of the high pressure 60 min pulping.... 77 3.5.3. Normal pressure organosolv pulping 78 3.6. Molecular Weight D i s t r i b u t i o n of Lignins After High Pressure Pulping 80 3.6.1. GPC Analysis 81 3.6.1.1. GPC conditions 81 3.6.1.2. C a l i b r a t i o n curve 82 3.6.1.3. GPC Injections 82 4. RESULTS AND DISCUSSION 83 4.1. Wood Species 83 4.2. Chemical Analysis of Wood 84 4.2.1. Determination of wood extractives i n the slash pine sample 85 4.2.2. Lignin from wood 87 4.3. Preliminary Studies for the Analysis of Resin- and Fatty Acids 88 4.3.1. Gas chromatographic studies 88 4.3.1.1. Time selection for methylation..90 4.3.1.2. Solvent s e l e c t i o n for methylation 92 ix 4.3.2. Preparation of c a l i b r a t i o n table 96 4.4. Analysis of Resin- and Fatty Acids i n Wood 97 4.4.1. Change of extractives i n storage ..102 4.4.1.1. Analysis of r e s i n - and f a t t y acids af t e r 6 weeks of storage 103 4.4.1.2. Analysis of r e s i n - and f a t t y acids i n wood af t e r 24 weeks of storage I l l 4.4.1.3. Analysis of r e s i n acids i n wood after 52 weeks of storage 117 4.5. Organosolv Pulping of Slash Pine 119 4.5.1. Resin- and f a t t y acids analysis a f t e r pulping 121 4.5.1.1. Resin- and f a t t y acids analysis af t e r 5 min pulping... 130 4.5.1.2. Resin- and f a t t y acids analysis aft e r 20 min pulping 134 4.5.1.3. Resin- and f a t t y acid analysis a f t e r 40 min pulping 140 4.5.1.4. Resin- and f a t t y acids analysis af t e r 60 min pulping 142 4.5.1.5. Complementary analyses of the r e s i n - and f a t t y acid a f t e r high pressure 60 min cooks 156 4.6. Characterization of Lignins 157 4.6.1. Quantitative analysis of l i g n i n 157 4.6.2. Molecular weight d i s t r i b u t i o n of l i g n i n 160 4.6.2.1. MWD of l i g n i n s from normal pressure cooks 160 X 4.6.2.2. MWD of l i g n i n from high pressure cooks 168 4.6.2.2.1. Soluble l i g n i n s i n the black l i q u o r . . . . 168 4.6.2.2.2. Complementary analyses of l i g n i n a f t e r a high pressure 60 min pulping 174 5. SUMMARY 180 6. CONCLUSIONS 183 7. BIBLIOGRAPHY 189 APPENDIX A 203 APPENDIX B 212 x i LIST OF FIGURES F i g # 1 A m o d e l f o r p h e n o l a g g r e g a t e s i n n e u t r a l r e s i n d u r i n g k r a f t p u l p i n g o f s e p e t i r p a y a 17 2 P h e n o l i c e x t r a c t i v e s r e s p o n s i b l e f o r t h e y e l l o w s p e c k s f r o m s e p e t i r p a y a wood 19 3 C h e m i c a l s t r u c t u r e s o f t h e m a j o r f a t t y a c i d s p r e s e n t i n s l a s h p i n e wood 21 4 M a i n h y d r o c a r b o n s k e l e t o n s f o r t h e r e s i n a c i d s . . 2 2 5 R e s i n a c i d m e t h y l e s t e r s o f t h e a b i e t a n e , p i m a r a n e a n d i s o p i m a r a n e s k e l e t o n s 24 6 D i s s o l u t i o n a n d c o m p o s i t i o n c h a n g e s o f e t h e r e x t r a c t i v e s on a c i d s u l f i t e p u l p i n g o f s p r u c e , s e a s o n e d b y d i f f e r e n t m e t h o d s , a n d o f g r e e n b i r c h w o o d 28 7 C h a n g e s i n t h e CIQ-IQ f a t t y a c i d c o m p o s i t i o n o f s p r u c e a n d b i r c h on a c i d s u l f i t e p u l p i n g a f t e r d i f f e r e n t t y p e s o f s e a s o n i n g 30 8 C h e m i c a l p r o d u c t s d e r i v a b l e f r o m e x t r a c t i v e s . . . 4 5 9 M a i n d i s t i l l a t e s o b t a i n e d f r o m c r u d e t a l l o i l a f t e r a c i d i f i c a t i o n 47 10 A p p a r a t u s u s e d f o r m e t h y l a t i o n o f t h e r e s i n a n d f a t t y a c i d s 56 11 F l o w d i a g r a m f o r t h e r e m o v a l , i d e n t i f i c a t i o n a n d q u a t i t a t i o n o f t h e r e s i n - a n d f a t t y a c i d s p r e s e n t i n s l a s h p i n e w o o d . A c i d s were d e t e r m i n e d as t h e i r m e t h y l e s t e r d e r i v a t i v e s . . . . 62 12a F l o w d i a g r a m f o r t h e r e c o v e r y , i d e n t i f i c a t i o n a n d q u a n t i f i c a t i o n o f t h e r e s i n -a n d f a t t y a c i d s i n t h e b l a c k l i q u o r a n d p u l p a f t e r h i g h p r e s s u r e o r g a n o s o l v p u l p i n g o f s l a s h p i n e wood 68 12b F l o w d i a g r a m f o r t h e r e c o v e r y , i d e n t i f i c a t i o n a n d q u a n t i f i c a t i o n o f t h e r e s i n -a n d f a t t y a c i d s i n t h e b l a c k l i q u o r a n d p u l p a f t e r n o r m a l p r e s s u r e o r g a n o s o l v p u l p i n g o f s l a s h p i n e wood 79 13 C a l i b r a t i o n c u r v e s f o r r e s i n a c i d s 99 14 C a l i b r a t i o n c u r v e s f o r f a t t y a c i d s 101 x i i 15 Gas c h r o m a t o g r a m o f t h e S o x h l e t m e t h a n o l e x t r a c t f r o m wood s t o r e d f o r 6 weeks u n d e r CTH room c o n d i t i o n s 105 16 M a s s s p e c t r a l t o t a l i o n c h r o m a t o g r a m o f t h e f r e e r e s i n - a n d f a t t y a c i d s 113 17 Mass s p e c t r a l t o t a l i o n c h r o m a t o g r a m o f t h e t o t a l r e s i n - a n d f a t t y a c i d s 114 18 R e l a t i v e p r o p o r t i o n o f r e s i n a c i d s i n s l a s h p i n e wood a f t e r 6, 24 a n d 52 weeks o f s t o r a g e . . 1 1 8 19 P h a s e d i a g r a m o f t h e t e r n a r y s o l v e n t m i x t u r e m e t h a n o l - w a t e r - d i e t h y l e t h e r : X a n d Y r e l a t i o n s h i p 124 20 P h a s e d i a g r a m o f t h e t e r n a r y s o l v e n t m i x t u r e m e t h a n o l - w a t e r - d i e t h y l e t h e r : T r i a n g u l a r r e l a t i o n s h i p 125 21 P r o p o s e d m e c h a n i s m f o r t h e b a s e - c a t a l y z e d i s o m e r i z a t i o n o f t h e c o n j u g a t e d d i e n i c r e s i n a c i d s 138 22 GPC c a l i b r a t i o n c u r v e w i t h p o l y s t y r e n e s t a n d a r d s 161 23 M o l e c u l a r w e i g h t d i s t r i b u t i o n c u r v e s o f l i g n i n s i s o l a t e d a f t e r n o r m a l p r e s s u r e o r g a n o s o l v p u l p i n g o f s l a s h p i n e 165 24 M o l e c u l a r w e i g h t d i s t r i b u t i o n c u r v e o f t h e d i s s o l v e d l i g n i n i s o l a t e d a f t e r n o r m a l p r e s s u r e o r g a n o s o l v p u l p i n g o f s l a s h p i n e 166 25 M o l e c u l a r w e i g h t d i s t r i b u t i o n o f t h e d i f f e r e n t l i g n i n s ( D i s s o l v e d , p r e c i p i t a t e d a n d t r a p p e d l i g n i n ) i s o l a t e d f r o m n o r m a l o r g a n o s o l v p u l p i n g o f s l a s h p i n e 167 2 6 D i s t r i b u t i o n c u r v e s o f t h e s o l u b l e l i g n i n s ( S - 5 , S-20) i s o l a t e d a f t e r a h i g h p r e s s u r e o r g a n o s o l v p u l p i n g o f s l a s h p i n e 169 27 D i s t r i b u t i o n c u r v e s o f t h e s o l u b l e l i g n i n s ( S - 4 0 , S-60) i s o l a t e d a f t e r a h i g h p r e s s u r e o r g a n o s o l v p u l p i n g o f s l a s h p i n e 170 28 M o l e c u l a r w e i g h t d i s t r i b u t i o n o f t h e s o l u b l e l i g n i n s ( S - 5 , S - 2 0 , S -40 a n d S-60) i s o l a t e d f r o m h i g h p r e s s u r e o r g a n o s o l v p u l p i n g o f s l a s h p i n e 171 x i i i 29 D i s t r i b u t i o n curves of the l i g n i n s i s o l a t e d d u r i n g the complementary a n a l y s i s a f t e r a 60 min h i g h p r e s s u r e organosolv p u l p i n g of s l a s h p i n e 177 30 M o l e c u l a r weight d i s t r i b u t i o n of " L i g n i n I I " , " L i g n i n P" and " L i g n i n S - 6 0 " a f t e r the 60 min cooking of s l a s h p i n e 178 x i v L I S T OF T A B L E S T A B L E # 1 E x t r a c t i v e s r e m o v a l b y d i f f e r e n t p u l p i n g s y s t e m s 15 2 E x t r a c t i v e s o f l o b l o l l y p i n e wood a n d b l a c k l i q u o r 32 3 R e s i n a c i d s o f l o b l o l l y p i n e wood 32 4 F a t t y a c i d s o f l o b l o l l y p i n e wood . . . . 3 3 5 F a t t y a c i d c o m p o s i t i o n o f s o u t h e r n p i n e s a p w o o d a n d k r a f t b l a c k l i q u o r 34 6 R e s i n a c i d s o f s l a s h p i n e s a p w o o d a n d k r a f t b l a c k l i q u o r 35 7 C o m p o s i t i o n o f t h e t a l l o i l p r e c u r s o r s o f s o u t h e r n p i n e s a p w o o d a n d k r a f t b l a c k l i q u o r e x t r a c t i v e s 36 8 E x t r a c t i v e s o f D o u g l a s - f i r wood a n d b l a c k l i q u o r 38 9 R a t e s o f m e t h y l a t i o n o f d e h y d r o a b i e t i c a c i d w i t h d i a z o m e t h a n e i n v a r i o u s s o l v e n t s 58 10 R a t i o t e s t i n g o f t h e r e s p o n s e a r e a o f d e h y d r o a b i e t i c a c i d r e l a t i v e t o t h e r e s p o n s e a r e a o f m e t h y l h e p t a d e c a n o a t e a f t e r 1 . 5 , 2 . 0 , 2 . 5 , 3 . 0 , 3 . 5 , 4 . 0 , 4 . 5 a n d 5 . 0 m i n u t e s o f m e t h y l a t i o n w i t h d i a z o m e t h a n e 91 11 R e s p o n s e f a c t o r s o f d e h y d r o a b i e t i c a n d a b i e t i c a c i d s (40 ng/u .L) a n d p a l m i t i c a c i d (50 n g / j i L ) a f t e r m e t h y l a t i o n i n d i e t h y l e t h e r - m e t h a n o l ( 9 : 1 ) , d i c h l o r o m e t h a n e -m e t h a n o l (9:1) a n d m e t h a n o l 94 12 R e s p o n s e f a c t o r s a n d r e l a t i v e r e s p o n s e a r e a s o f t h e i n d i v i d u a l m a j o r r e s i n a c i d s o f s l a s h p i n e w i t h r e s p e c t t o t h e r e s p o n s e a r e a o f m e t h y l h e p t a d e c a n o a t e 98 13 R e s p o n s e f a c t o r s , r e l a t i v e r e s p o n s e f a c t o r s a n d r e l a t i v e r e s p o n s e a r e a s o f t h e i n d i v i d u a l m a j o r f a t t y a c i d s o f s l a s h p i n e w i t h r e s p e c t t o t o t h e r e s p o n s e a r e a o f m e t h y l h e p t a d e c a n o a t e 100 14 R e s i n - a n d f a t t y a c i d c o m p o s i t i o n o f s l a s h p i n e wood a f t e r 6 weeks o f s t o r a g e 106 X V 15 R e l a t i v e p r o p o r t i o n o f r e s i n a c i d s i n s l a s h p i n e wood a f t e r 6 weeks o f s t o r a g e 108 16 R a t i o s o f t h e r e l a t i v e i n t e n s i t i e s o f t h e m/e 2 3 9 / 2 4 1 a n d m/e 3 0 1 / 3 1 6 mass p e a k s o f l e v o p i m a r i c a n d p a l u s t r i c a c i d s on s l a s h p i n e wood a f t e r 6 weeks o f s t o r a g e 110 17 R e s i n - a n d f a t t y a c i d s p r e s e n t i n s l a s h p i n e (Pinus elliottii E n g e l m . ) a f t e r a 24 weeks s t o r a g e 112 18 R e s i n - a n d f a t t y a c i d c o m p o s i t i o n o f s l a s h p i n e wood a f t e r 6 a n d 24 weeks s t o r a g e 116 19 R e l a t i v e p r o p o r t i o n o f r e s i n a c i d s i n s l a s h p i n e wood a f t e r 6, 24 a n d 52 weeks s t o r a g e 117 20 D a t a f o r t h e p h a s e d i a g r a m s e p a r a t i o n o f t h e t e r t i a r y s o l v e n t m i x t u r e m e t h a n o l -w a t e r - d i e t h y l e t h e r 123 21 R e s i n - a n d f a t t y a c i d c o m p o s i t i o n i n s l a s h p i n e wood a n d b l a c k l i q u o r a f t e r 5 m i n u t e s o r g a n o s o l v p u l p i n g 132 22 R e s i n - a n d f a t t y a c i d p r o p o r t i o n s f o l l o w i n g 20 m i n o r g a n o s o l v p u l p i n g o f s l a s h p i n e 135 23 R e s i n - a n d f a t t y a c i d p r o p o r t i o n s f o l l o w i n g 40 m i n o f o r g a n o s o l v p u l p i n g o f s l a s h p i n e . . . . 1 4 1 24 R e s i n - a n d f a t t y a c i d c o m p o s i t i o n i n s l a s h p i n e a f t e r 60 m i n o r g a n o s o l v p u l p i n g 143 25 T h e r m a l i s o m e r i z a t i o n o f n e o a b i e t i c a n d l e v o p i m a r i c a c i d a t 2 0 0 2 C f o r 30 m i n 149 2 6 T h e r m a l i s o m e r i z a t i o n o f l e v o p i m a r i c a c i d a t 155 a n d 2 0 0 2 C 150 27 R e s i n - a n d f a t t y a c i d c o m p o s i t i o n o f s l a s h p i n e wood a n d t h e i r r e c o v e r y a f t e r 5 , 2 0 , 40 a n d 60 m i n o r g a n o s o l v p u l p i n g 155 28 M a s s b a l a n c e o f l i g n i n , r e s i n a n d f a t t y a c i d s o f s l a s h p i n e wood a f t e r o r g a n o s o l v p u l p i n g 158 2 9 A p p a r e n t M w a n d M n o f l i g n i n s a f t e r n o r m a l p r e s s u r e o r g a n o s o l v p u l p i n g 162 xvi 30 Molecular weight d i s t r i b u t i o n ranges of the d i f f e r e n t l i g n i n fractions obtained with normal (autogenous) pressure cooks 164 31 Apparent M w and M^  of the soluble l i g n i n s af t e r the 5, 20, 40 and 60 min organosolv pulping of slash pine wood 172 32 Percentage of the molecular weight ranges of the d i f f e r e n t soluble l i g n i n f r a c t i o n s from high pressure organosolv cooks of slash pine wood 175 33 Apparent M w and MQ of Lignin II, Lignin P and Lignin S-60 a f t e r the 60 min cooking 176 x v i i ACKNOWLEDGEMENTS I w i s h t o a c k n o w l e d g e , w i t h g r a t i t u d e , t h e e x p e r t g u i d a n c e a n d i n v a l u a b l e h e l p t h r o u g h o u t my g r a d u a t e s t u d i e s a t UBC, o f my R e s e a r c h S u p e r v i s o r D r . L. P a s z n e r , P r o f e s s o r , F a c u l t y o f F o r e s t r y . T h a n k s a r e a l s o e x t e n d e d t o t h e members o f my S u p e r v i s o r y C o m m i t t e e f o r r e v i e w i n g t h i s t h e s i s , e s p e c i a l l y t o D r . R.W. K e n n e d y f o r h i s c o r r e c t i o n s , u s e f u l s u g g e s t i o n s a n d c r i t i c i s m s . T h a n k s a l s o go t o D r . A. K o z a k f o r v a l u a b l e s t a t i s t i c a l c o n s u l t a t i o n s , a n d t o D r . J.W. W i l s o n f o r h i s a s s i s t a n c e a n d c o n t i n u o u s b i b l i o g r a p h i c a l s u p p l y . A p p r e c i a t i o n i s e x t e n d e d t o D r . B. K o s i k o v a f o r h e r r e v i s i o n s , c r i t i c i m s a n d v a l u a b l e d i s c u s s i o n s . S p e c i a l t h a n k s a r e due t o D r . S. E l l i s , F a c u l t y o f F o r e s t r y , f o r h i s v a l u a b l e a s s i s t a n c e w i t h t h e GPC a n a l y s e s . G r a t e f u l a c n o w l e d g e m e n t i s made t o F. B a l z a , R e s e a r c h S c i e n t i s t , D e p a r t m e n t o f B o t a n y , f o r h i s h e l p d u r i n g t h e mass s p e c t r o m e t r i c s t u d i e s a n d i n t e r e s t i n g comments a n d s u g g e s t i o n s . S i n c e r e a c k n o w l e d g e m e n t i s made t o E. L e e a n d C. L a i f o r t h e i r a d m i n i s t r a t i v e a s s i s t a n c e d u r i n g my s t a y h e r e a t F o r e s t r y . I e x p r e s s my d e e p e s t g r a t i t u d e t o my w i f e , R o x a n a , a n d t o my l i t t l e "Queen", R o x a n i t a , f o r t h e i r p a t i e n c e a n d e n d u r a n c e t h r o u g h o u t my s t u d i e s . F i n a l l y , I w o u l d a l s o l i k e t o t h a n k t h e C a n a d i a n I n t e r n a t i o n a l D e v e l o p i n g A g e n c y f o r t h e i r f i n a n c i a l s u p p o r t x v i i i during my studies at UBC. Many thanks to the National Agrarian University "La Molina", Lima-Peru, for granting me a leave of absence during t h i s period. xix A B B R E V I A T I O N S USED BCR - B r i t i s h Columbia Research CTH - Control Temperature and Humidity FFA - Free Fatty Acids GC - Gas Chromatography GC-MS - Gas chromatography-Mass spectrometry GPC - Gel Permeation Chromatography HPLC - High Pressure Liquid Chromatography IR - Infrared Mn - Number Average Molecular Weight Mw - Weight Average Molecular Weight MTBE - Methyl Tert-Butyl Ether MWD - Molecular Weight D i s t r i b u t i o n NCASI - National Council of the Paper Industry for A i r and Stream Improvement RAFA - Resin Acids and Fatty Acids TAPPI - Technical Association of the Pulp and Paper Industry THF - Tetrahydrofuran TLC - Thin Layer Chromatography UV/VIS - U l t r a v i o l e t / V i s i b l e XX To my wife, Roxana, and t o my l i t t l e "Queen" Roxanita 1 1. INTRODUCTION S i n c e e a r l y d a y s , humans h a v e u s e d e x t r a c t i v e s o f t r e e s s u c h as p i g m e n t s , r e s i n s , t u r p e n t i n e , t a n n i n s , p h e n o l i c s , a l k a l o i d s a n d gums, i n many d i f f e r e n t ways a n d h a v e d e v e l o p e d t h e i r own c u l t u r e . I n a m o d e r n i n d u s t r i a l i z e d s o c i e t y , mos t o f t h e s e s u b s t a n c e s h a v e b e e n r e p l a c e d b y s y n t h e t i c p r o d u c t s a n d s e e m i n g l y h a v e come c l o s e t o l o s i n g t h e i r v a l u e i n c i v i l i z e d l i f e ( O h a r a e t al., 1 9 8 6 ) . T a l l o i l a n d p i n e t u r p e n t i n e p r o d u c t s h a v e g a i n e d i n d u s t r i a l s i g n i f i c a n c e r e c e n t l y a n d b e s i d e s t r a d i t i o n a l u s e s ( c o s m e t i c s , p a i n t s , v a r n i s h e s a n d a d h e s i v e s ) h a v e now a l s o b e e n p r o p o s e d as a s o u r c e o f d i e s e l f u e l , a n d e n e r g y f o r s t e a m a n d e l e c t r i c p o w e r g e n e r a t i o n ( L i p i n s k y e t al., 1 9 8 5 ) . G e n e r a l l y , t h e e f f e c t o f e x t r a c t i v e s h a s b e e n t o t a l l y i g n o r e d i n o r g a n o s o l v p u l p i n g a n d t h e y were n e i t h e r a c c o u n t e d f o r a s n e u t r a l s o l v e n t - s o l u b l e s i n t h e p u l p n o r s e p a r a t e d f r o m t h e l i g n i n a n d s u g a r s a s b y - p r o d u c t s d u r i n g r e c o v e r y o f t h e s o l v e n t . I n c r e a s e d i n t e r e s t c o n c e r n i n g p u r e c h e m i c a l s a n d a l t e r n a t e raw m a t e r i a l s , d e r i v e d f r o m l i g n o c e l l u l o s i c m a t e r i a l s , i s due m a i n l y t o t h e r i s e i n c o s t a n d p e r c e i v e d 2 l o n g - t e r m s h o r t a g e s i n f o s s i l a n d n o n - r e n e w a b l e raw m a t e r i a l s u s e d b y t h e c h e m i c a l a n d f u e l i n d u s t r i e s ( S u o m i , 1 9 8 3 ) . On t h e o t h e r h a n d , e v e r - i n c r e a s i n g f o r e i g n t r a d e among n a t i o n s o f t h e w o r l d demands c a r e f u l a t t e n t i o n t o p r o d u c t i o n e c o n o m i c s i n w h i c h w a s t e u t i l i z a t i o n a n d b y -p r o d u c t r e c o v e r y c a n p l a y a s i g n i f i c a n t r o l e , e s p e c i a l l y i n t h e p u l p a n d p a p e r i n d u s t r y . T o d a y , m o s t l y l o w e x t r a c t i v e - c o n t e n t wood s p e c i e s a r e s e l e c t e d b y t h e p u l p i n g i n d u s t r y b e c a u s e o f l o w e r c h e m i c a l ( a l k a l i ) c o n s u m p t i o n , t h e e a s e o f p u l p i n g , b l e a c h a b i l i t y a n d / o r p a p e r m a k i n g . E x t r a c t i v e s a r e known t o i n t e r f e r e w i t h n o r m a l d e l i g n i f i c a t i o n ( R y d h o l m , 1 9 8 5 ) , c a u s e c o l o r r e v e r s i o n i n b l e a c h i n g ( A k i m o t o a n d S u m i m o t o , 1980; H o s o k a w a e t al., 1983 ; G u l l i c h s e n a n d S o d e r h j e l m , 1984; S a n u s i e t al., 1985) a n d p i t c h b u i l d up on p a p e r m a c h i n e s ( M c M i l l i n , 1 9 6 9 ; Y a t a g a i a n d T a k a h a s h i , 1 9 8 0 ; T a c h i b a n a a n d S u m i m o t o , 1980; T a c h i b a n a a n d S u m i m o t o , 1982) a n d r e d u c e f i b e r b o n d i n g i n f o r m a t i o n o f p a p e r webs ( B r a n d a l a n d L i n d h e i m , 1966; M c M i l l i n , 1969) . E x t r a c t i v e s d u r i n g d e l i g n i f i c a t i o n a n d s u b s e q u e n t w a s h i n g s a n d b l e a c h i n g a r e l a r g e l y r e m o v e d f r o m t h e f i b e r s . C h e m i c a l c o n s u m p t i o n i s a n i m p o r t a n t f a c t o r t o be c o n s i d e r e d i f a new p u l p i n g p r o c e s s i s t o b e s e l e c t e d . F r o m t h i s p e r s p e c t i v e , e v e n h i g h e x t r a c t i v e - c o n t e n t woods ( i . e . a s a l s o i n some t r o p i c a l woods) w i t h s u i t a b l e f i b r e p r o p e r t i e s m i g h t be g o o d a l t e r n a t i v e s i f b o t h t h e 3 l i g n o c e l l u l o s i c components (pulp, sugars and lignin) and the extractives could be used i n the future. The more than 50 years of organosolv pulping l i t e r a t u r e was t o t a l l y s i l e n t on the e f f e c t of wood extractives during pulping and contained no information whatsoever on the apparent disappearance or chemical changes which may take place when unextracted woods containing notable amounts of extractives are pulped. Behera (1985) indicated that unbleached Douglas-fir organosolv pulp was low i n residual extractives but did not account for the presence of the extractives i n his spent l i q u o r . It therefore appears that the extractives are l a r g e l y removed from the wood substance during pulping, and might be either l o s t from the spent li q u o r being adsorbed on the p r e c i p i t a t e d l i g n i n or undergo high-temperature fragmentation reactions to solvent/water soluble products during pulping. Since extractives are removed extensively from the fi b e r s during high temperature organosolv pulping, even during short cooking periods i t i s hypothesized that: 1. ) The pulping conditions are f a i r l y severe and i t appears reasonable to expect chemical and s t r u c t u r a l changes i n the extractives during organosolv pulping. 2. ) Isol a t i o n of the extractives from the spent liquor must f a c i l i t a t e t h e i r handling for further use as by-products. Furthermore, i t would be desirable to 4 r e c o v e r a c l e a n e r a n d more r e a c t i v e l i g n i n s u i t a b l e f o r u s e i n i t s p o l y m e r i c f o r m ( V e n t e r a n d V a n d e r K l a s h o r s t 1 9 8 9 ) . S i m i l a r l y , r e c o v e r y o f e x t r a c t i v e -f r e e s u g a r s o l u t i o n s , r e a d y f o r f e r m e n t a t i o n o r o t h e r a p p l i c a t i o n s , a p p e a r s t o b e d e s i r a b l e . 5 2. LITERATURE REVIEW 2 .1 . Wood Extractives 2 .1 .1 . Background Extraneous materials present i n wood are considered e x t r a c e l l u l a r wall constituents. They consist primarily of organic, non-polymeric compounds which can be extracted with water, neutral organic solvents or v o l a t i l i z e d by steam (Rowe and Conner, 1979; Fengel and Wegener, 1984) . In a narrow sense, the term extractives covers those compounds which are soluble i n water and organic solvents. For t h e i r removal neutral solvent extraction i s used p r i o r to chemical characterization of woods (Fengel and Wegener 1984) . Broadly speaking, water-soluble carbohydrates and inorganic compounds are also included i n t h i s group (Fengel and Wegener, 1984) . Many wood species are characterized by s p e c i f i c chemical composition of t h e i r extractable materials. Extractives are known to influence u t i l i t y of wood for pulp and paper (Akimoto and Sumimoto, 1980) and for many other wood-based industries, p a r t i c u l a r l y where decay resistance i s of primary concern (Rowe and Conner, 1979). According to Fengel and Wegener (1984), the amount of soluble material i n organic solvents i s only a few percent 6 i n t h e wood o f t r e e s f r o m t h e t e m p e r a t e z o n e s , b u t may be s u b s t a n t i a l i n c e r t a i n p a r t s o f t h e t r e e , e . g . i n b r a n c h e s , h e a r t w o o d , r o o t s , a n d a r e a s o f i r r i t a t i o n (wounding ) . M o s t o f t h e e x t r a c t i v e s a r e l o c a t e d i n t h e h e a r t w o o d a n d t h e i r p r e s e n c e i s r e s p o n s i b l e f o r t h e d a r k e n i n g o f t h i s p o r t i o n o f t h e t r e e . T h e t o x i c i t y o f mos t o f t h e e x t r a c t i v e m a t e r i a l s p r e s e n t i n t h e h e a r t w o o d makes t h i s p a r t o f t h e t r e e r e l a t i v e l y r e s i s t a n t t o a t t a c k b y d e c a y o r g a n i s m s ( K o l l m a n n a n d C 6 t e , 1 9 6 8 ) . E x t r a c t i v e s a r e i m p o r t a n t b e c a u s e o f t h e i r c o n t r i b u t i o n t o t h e p r o p e r t i e s o f w o o d . Many woods c o n t a i n e x t r a c t i v e s w h i c h a r e t o x i c t o b a c t e r i a , f u n g i a n d t e r m i t e s ( B a u c h e t al., 1977 ; S a m e s h i m a e t al., 1978; W e i s s m a n n a n d D i e t r i c h s , 1975 ; Y a z a k i , 1982; F r a n i c h a n d G a d g i l , 1 9 8 3 ; MacRae a n d T o w e r s , 1 9 8 4 ) . O t h e r e x t r a c t i v e s c a n a d d c o l o r a n d o d o r t o wood , a c c e n t t h e g r a i n p a t t e r n a n d e n h a n c e s t r e n g t h p r o p e r t i e s ( B a r t o n , 1976 ; W i l c o x a n d P i i r t o , 1976; Rowe a n d C o n n e r , 1979) . On t h e o t h e r h a n d , e x t r a c t i v e s c a n c a u s e c o r r o s i o n o f m e t a l s i n c o n t a c t w i t h wood (Rowe a n d C o n n e r , 1 9 7 9 ) , i n h i b i t s e t t i n g o f c o n c r e t e , g l u e s , a n d f i n i s h e s (Abe a n d O n o , 1 9 8 0 ) , p r o l o n g p a i n t c u r i n g t i m e ( Y a t a g a i a n d T a k a h a s h i , 1 9 8 0 ) , b l o c k t h e r e a c t i v e g r o u p s on t h e s u r f a c e o f t h e f i b e r s r e d u c i n g t h e i r b o n d i n g c a p a c i t y ( B r a n d a l a n d L i n d h e i m , 1966; M c M i l l i n , 1 9 6 9 ) , c o n t r i b u t e t o c o l o r r e v e r s i o n o f t h e 7 p u l p s ( C r o o n e t al., 1966; V e n k o v a Rao e t al., 1 9 8 1 ) , c a u s e p i t c h p r o b l e m s d u r i n g p a p e r m a k i n g ( M c M i l l i n , 1969 ; Y a t a g a i a n d T a k a h a s h i , 1980; T a c h i b a n a a n d S u m i m o t o , 1980; T a c h i b a n a a n d S u m i m o t o , 1 9 8 2 ) , a n d b l e e d t h r o u g h f i n i s h e s a f f e c t i n g t h e c o l o r s t a b i l i t y o f wood t o l i g h t (Rowe a n d C o n n e r , 1979) . I n t h i s s e n s e , e x t r a c t i v e s a r e p a r t a n d p a c k a g e o f wood f o r m a t i o n ; t h e i r s p e c i f i c c o m p o s i t i o n i s c o n t r o l l e d b y b i o l o g i c a l a c t i v i t y d u r i n g wood f o r m a t i o n a n d s u b s e q u e n t m a t u r i n g o f t h e woody c e l l s . T h e r e b y , t h e wood i n d u s t r y h a s t o l e a r n how t o d e a l w i t h t h e m a n d u t i l i z e t h e m t o t h e b e s t p o s s i b l e a d v a n t a g e . 2.2 . Chemical Composition of Wood Extractives T h e r e i s a p a r t o f t h e e x t r a c t i v e s t e r m e d r e s i n s t h a t d o e s n o t c h a r a c t e r i z e c e r t a i n c h e m i c a l c o m p o u n d s , b u t must r a t h e r b e c o n s i d e r e d a p h y s i c a l c o n d i t i o n ( F e n g e l a n d W e g e n e r , 1 9 8 4 ) . A c c o r d i n g t o S a n d e r m a n n ( 1 9 6 0 ) , t h e t e r m " r e s i n " seems t o b e a m i x t u r e o f d i f f e r e n t c o m p o u n d s w h i c h m u t u a l l y i n h i b i t c r y s t a l l i z a t i o n . E x t r a c t i v e s f r o m b o t h s o f t w o o d s a n d h a r d w o o d s c a n be c l a s s i f i e d i n t o g r o u p s l i k e : t e r p e n e s a n d t e r p e n o i d s , f a t s , w a x e s , a n d t h e i r c o m p o n e n t s , p h e n o l i c a n d 8 p o l y p h e n o l i c compounds a n d o t h e r s ( F e n g e l a n d W e g e n e r , 1984) . M o s t o f t h e s e c o n d a r y e x t r a c t i v e s a r e l o c a t e d i n t h e r e s i n c a n a l s a n d t h e r a y p a r e n c h y m a c e l l s ( M u t t o n , 1959 ; B a c k , 1 9 6 0 ) . I n l o w e r a m o u n t s t h e y a r e f o u n d i n t h e m i d d l e l a m e l l a , i n t e r c e l l u l a r s p a c e s a n d t h e c e l l w a l l s o f t r a c h e i d s a n d l i b r i f o r m f i b r e s ( B a c k , 1 9 6 0 ; P a a s o n e n , 1967) . I n no c a s e a r e t h e y c h e m i c a l l y l i n k e d t o t h e c e l l w a l l m a t r i x c o m p o n e n t s ( c e l l u l o s e , h e m i c e l l u l o s e s a n d l i g n i n ) . T h i s a l l o w s t h e i r s o l u b i l i z a t i o n i n s u i t a b l e s o l v e n t s w i t h o u t d i s t u r b i n g t h e c e l l w a l l . T h e c o n t e n t a n d c o m p o s i t i o n o f wood e x t r a c t i v e s v a r i e s among wood s p e c i e s . T h i s v a r i a t i o n may be p a r t i a l l y c o n t r o l l e d a n d m o d i f i e d b y e n v i r o n m e n t a l c o n d i t i o n s i n c l u d i n g s e a s o n , n u t r i t i o n a l s t a t e , p a r t i c u l a r t i s s u e b e i n g s t u d i e d , a n d f u r t h e r v a r i e d i f t h e t r e e i s u n d e r a t t a c k b y d e c a y i n g m i c r o o r g a n i s m s t h a t w i l l p r o v o k e r e s p o n s e r e a c t i o n s (Swan, 1968; Dahm, 1970; Rowe a n d C o n n e r , 1 9 7 9 ) . V a r i a t i o n s i n c h e m i c a l c o m p o s i t i o n a n d amount o f wood e x t r a c t i v e s h a v e b e e n e x t e n s i v e l y s t u d i e d on many s p e c i e s l i k e s p r u c e s , p i n e s o r b i r c h e s . I t h a s b e e n shown t h a t s o f t w o o d l o g s e a s o n i n g i n v o l v e s s l o w e n z y m a t i c e s t e r h y d r o l y s i s a n d o x i d a t i o n o f u n s a t u r a t e d a c i d s ( D o n e t z h u b e r a n d Swan, 1 9 6 5 ) . C o n v e r s e l y , t h e e x t r a c t i v e s c o n t e n t i n b i r c h r e m a i n s c o n s t a n t d u r i n g s e a s o n i n g a n d i s a s h i g h 9 a f t e r two y e a r s o f s t o r a g e , a s i n f r e s h wood ( D o n e t z h u b e r a n d Swan, 1 9 6 5 ) . A c c o r d i n g t o A s s a r s s o n ( 1 9 6 9 ) , d u r i n g o u t s i d e c h i p s t o r a g e some u n d e s i r a b l e m i c r o b i o l o g i c a l a n d c h e m i c a l p r o c e s s e s may o c c u r , c a u s i n g a s e r i o u s d e t e r i o r a t i o n i n t h e q u a l i t y o f t h e c h i p s . I t was a l s o f o u n d t h a t t h e r e s i n c o m p o s i t i o n i s m o d i f i e d b y b i o c h e m i c a l a n d c h e m i c a l r e a c t i o n s . I n t h i s r e g a r d , f a t s a n d waxes ( e s t e r s ) a r e e n z y m a t i c a l l y h y d r o l y z e d t o f a t t y a c i d s a n d h i g h e r a l c o h o l s , w h i c h c a n be m e t a b o l i z e d b y m i c r o b i a l r e s p i r a t i o n t o c a r b o n d i o x i d e a n d w a t e r ( S e l l e b y , 1 9 6 5 ) . A c c o r d i n g t o A s s a r s s o n (1969) t h e amount a n d c h e m i c a l s t r u c t u r e o f t h e wood e x t r a c t i v e s c h a n g e d u r i n g s e a s o n i n g , a n d t h e s e c h a n g e s a r e more d r a s t i c a t t h e b e g i n n i n g a n d s u b s e q u e n t l y s l o w down a f t e r f i v e o r s i x m o n t h s . He a l s o s t a t e d t h a t o u t s i d e c h i p s t o r a g e i n f l u e n c e s t h e r e s i n c o m p o s i t i o n b y b i o c h e m i c a l a n d o r g a n i c c h e m i c a l r e a c t i o n s i n w h i c h e s t e r s , l i k e f a t s a n d waxes a r e e n z y m a t i c a l l y h y d r o l y z e d t o f a t t y a c i d s a n d h i g h e r a l c o h o l s , r e s p e c t i v e l y ( A s s a r s s o n 1 9 6 9 ) . A f t e r f o u r weeks o f o u t s i d e s t o r a g e o f c h i p s , t h e t a l l o i l y i e l d i s r e d u c e d b y 40 - 50 % o f t h a t o r i g i n a l l y o b t a i n a b l e f r o m t h e g r e e n w o o d . T h i s d e c r e m e n t m i g h t be due t o b i o l o g i c a l a c t i v i t y a n d a u t o x i d a t i o n r e a c t i o n s ( C h a l k , 1968) . 10 2.3. Organosolv Pulping In general, during a chemical pulping process wood i s treated with chemicals at high temperature i n pressurized vessels. The main goal of any chemical pulping process i s to degrade l i g n i n ( l i g n i n s o l volysis) leaving the c e l l u l o s i c material as the major f r a c t i o n of the r e s u l t i n g pulp. The extractives, which are a minor e x t r a c e l l u l a r extraneous f r a c t i o n of the organic compounds i n the wood, are also subject to the severe conditions and are largely removed during the pulping process. Most chemical pulping processes can be grouped according to the main chemical which i s used to d e l i g n i f y wood. Thereby, there w i l l be two groups of processes i f organic or inorganic chemicals are used as d e l i g n i f y i n g agents. If organic solvents are used, these chemical processes are refered to as "organosolv" pulping processes. The leading inorganic pulping processes are the kraft and s u l f i t e processes. In general, i n d u s t r i a l pulping developments are motivated by economical and environmental considerations (Lora and Aziz, 1985; Aziz and McDonough, 1987) . The established pulp and paper industry would l i k e to increase pulp y i e l d , improve pulp quality, and reduce both water and a i r p o l l u t i o n (Kleinert, 1974) . Other considerations such as energy, raw material, and economy provide 11 i n c e n t i v e s f o r i n t r o d u c t i o n o f a l t e r n a t i v e p r o c e s s e s i n o r d e r t o i m p r o v e t h e w o r l d m a r k e t p o s i t i o n o f c h e m i c a l p u l p s ( S a u l , 1979 ; C a s e y , 1983 ; P a s z n e r a n d B e h e r a , 1 9 8 5 ) . L a t e l y , new, more e f f e c t i v e a n d c h e a p e r p u l p i n g p r o c e s s e s h a v e b e e n s u g g e s t e d (Cox a n d W o r s t e r , 1 9 7 1 ; P a s z n e r a n d B e h e r a , 1 9 8 5 ; S a u l , 1 9 7 9 ) . T h e s e same c o n s i d e r a t i o n s m o t i v a t e d o r g a n o s o l v p u l p i n g t r i a l s b y K l e i n e r t a n d T a y e n t h a l i n 1931 u s i n g a q u e o u s e t h a n o l as t h e p u l p i n g s o l v e n t f o r woods a t t e m p e r a t u r e s s i m i l a r t o t h o s e u s e d i n k r a f t p u l p i n g . I n Q l a t e r e x p e r i m e n t s w i t h e t h a n o l - w a t e r e x p e r i m e n t s a t 185 C a t a c o n c e n t r a t i o n o f (50 :50 e t h a n o l - w a t e r ) , i t was shown t h a t a q u e o u s o r g a n i c s o l v e n t s a r e p o w e r f u l a g e n t s f o r d e l i g n i f i c a t i o n o f b o t h h a r d w o o d s a n d s o f t w o o d s ( K l e i n e r t , 1 9 7 4 ) . S u b s e q u e n t l y , d u r i n g t h e l a s t 50 y e a r s s e v e r a l n o n -c o n v e n t i o n a l s o l v e n t p u l p i n g m e t h o d s h a v e b e e n i n v e s t i g a t e d . O r g a n i c s o l v e n t s a s d e l i g n i f y i n g a g e n t s c a n b e g r o u p e d as l o w a n d h i g h b o i l i n g p o i n t s o l v e n t s ( A z i z a n d S a r k a n e n , 1 9 8 9 ) . Among t h e m o s t common o r g a n i c s o l v e n t s a r e : a) a l i p h a t i c alcohols: m e t h a n o l ( P a s z n e r , 1 9 8 9 ) , e t h a n o l ( K l e i n e r t , 1974; F a a s s e t al., 1 9 8 9 ) , b u t a n o l (K611 a n d L e n h a r d t , 1 9 8 7 ) , c h l o r o e t h a n o l (Nimz et al., 1 9 8 6 ) , e t h y l e n e g l y c o l ( N e l s o n , 1 9 7 7 , K611 a n d L e n h a r d t , 1 9 8 7 ) ; b) amines: e t h a n o l a m i n e ( E n k v i s t a n d M o i l a n e n , 1 9 4 9 ) , e t h y l e n e d i a m i n e (Kubes a n d B o l k e r , 1978; 12 Z a r g a r i a n et al., 1988); c ) k e t o n e s : a c e t o n e , m e t h y l e t h y l k e t o n e , c y c l o h e x a n o n e (DeHaas a n d L a n g , 1 9 7 4 ) , d ) o r g a n i c a c i d s : f o r m i c a c i d (Ede a n d Brunow, 1989), a c e t i c a c i d (Young e t a l . , 1986); e ) e s t e r s : e t h y l a c e t a t e (Young a n d B a i e r l , 1985); f ) p h e n o l s : p h e n o l ( S c h w e e r s , 1 9 7 4 ) , c r e s o l s (Sano e t al., 1989; Sano, 1989). S e v e r a l c a t a l y s t s h a v e b e e n u s e d i n a q u e o u s m e t h a n o l a n d e t h a n o l b u t o n l y f e w p o s s e s s s p e c i f i c a d v a n t a g e s as c a t a l y s t s ( A z i z a n d S a r k a n e n , 1 9 8 9 ) . F l e m i n g (1985) g i v e s t h e f o l l o w i n g l i s t o f c a t a l y s t s u s e d i n c o m b i n a t i o n w i t h d i f f e r e n t o r g a n i c s o l v e n t s : a ) m e t h a n o l : C a C l 2 , M g ( N 0 3 ) 2 , M g S 0 4 , b ) e t h a n o l : A l s a l t s , ( N H 4 ) 2 S , N H 3, HCOOH, NaOH, NaHC03 + m e t h y l a n t h r a q u i n o n e (AQ), c ) i s o p r o p a n o l : N a H S 0 3 , N a 2 S 0 3 , d ) b u t a n o l : HN0 3, AQ, e ) p h e n o l : HC1, f ) a c e t o n e : N H 3 , g ) c y c l o h e x a n o n e : N H 3 , h ) s u l f o l a n e : N a 2 S , H 2 S 0 4 . Youn g a n d D a v i s ( 1 9 8 6 ) , w o r k i n g w i t h a s p e n c h i p s i n aq u e o u s a c e t i c a c i d (50-87.5%) f o r up t o two h o u r s a t t e m p e r a t u r e b e t w e e n 160-185°C, a c h i e v e d g o o d d e l i g n i f i c a t i o n (Kappa numbers 10-40) w i t h p u l p y i e l d s r a n g i n g b e t w e e n 5 0 - 6 0 % . A l i q u o r - t o - w o o d r a t i o o f 4:1 t o 8:1 was a d e q u a t e f o r t h i s p u r p o s e . They a l s o f o u n d t h a t l i g n i n r e m o v a l c o u l d be done w i t h a s l o w a s 5 0 % a c e t i c a c i d a n d t h a t t h e d e l i g n i f i c a t i o n s e l e c t i v i t y was i m p r o v e d a t h i g h e r s o l v e n t c o n c e n t r a t i o n s . 13 Y o u n g e t al. (1985) d e s c r i b e d an a l t e r n a t e p u l p i n g p r o c e s s b a s e d on e t h y l a c e t a t e / a c e t i c a c i d / w a t e r . D u r i n g t h i s p r o c e s s e t h y l a c e t a t e i s p r o p o s e d a s t h e s u b s t i t u t e s o l v e n t f o r w a t e r i n t h e a c e t i c a c i d p u l p i n g w h i c h shows t h e f o l l o w i n g a d v a n t a g e s : R e d u c e d c o o k i n g t i m e , l o w e r p u l p i n g t e m p e r a t u r e s f o r g i v e n c o o k i n g p r e s s u r e s , h i g h e r s t r e n g t h p u l p s , h i g h e r y i e l d s , e n h a n c e d s o l u b i l i t y o f l i g n i n i n t h e p u l p i n g s o l v e n t , a n d s i m p l i f i e d r e c o v e r y o f o r g a n i c c h e m i c a l s . O r g a n o s o l v p u l p i n g o f Eucalyptus regnans, Pinus radiata and Pinus e l l i o t t i i was p e r f o r m e d b y t r e a t m e n t w i t h e t h y l e n e g l y c o l s o l u t i o n s o f s a l i c y l i c a c i d d e r i v a t i v e s a t 170 a n d 195°C ( N e l s o n , 1 9 7 7 ) . I t was f o u n d t h a t E u c a l y p t u s wood (E. regnans) was e a s i l y d e l i g n i f i e d w i t h a t h r e e p e r c e n t s o l u t i o n o f a s p i r i n o r s a l i c y l i c a c i d i n g l y c o l a t 170°C. When m e t h y l s a l i c y l a t e o r g l y c o l s a l i c y l a t e w e r e u s e d , more v i g o r o u s c o n d i t i o n s were r e q u i r e d . F u r t h e r m o r e , i t was f o u n d t h a t P. radiata was more d i f f i c u l t t o d e l i g n i f y t h a n E. regnans, a n d a l s o t h a t P. e l l i o t t i i was e v e n more d i f f i c u l t t o p u l p t h a n P. radiata. I n t e n s i v e d e v e l o p m e n t p r o g r a m s a r e u n d e r w a y a t l a b o r a t o r i e s t h r o u g h o u t t h e w o r l d t o i m p r o v e t h e o r g a n o s o l v p u l p i n g p r o c e s s e s ( K a t z e n e t al., 1980; M a r t o n a n d G r a n z o w , 1982; L i p i n s k y , 1 9 8 3 ) . A m a j o r d r a w b a c k o f t h e s e p r o c e s s e s h a s b e e n t h e i r i n a b i l i t y t o p u l p s o f t w o o d s 14 a d e q u a t e l y ( S a r k a n e n e t al., 1978) a n d t o p r o d u c e h i g h y i e l d p u l p s w i t h s m a l l amount o f r e j e c t s ( P a s z n e r a n d B e h e r a , 1 9 8 5 ) . O r g a n o s o l v p u l p i n g f o r a l l wood s p e c i e s h a s b e e n p o s s i b l e b y u s i n g a l k a l i n e - e a r t h - s a l t - c a t a l y s t s i n a q u e o u s m e t h a n o l (75-85 %) a s t h e s o l v e n t ( P a s z n e r a n d B e h e r a , 1 9 8 5 ) . A d v a n t a g e s o f t h i s p r o c e s s i n c l u d e h i g h p u l p y i e l d , e a s e o f b l e a c h i n g , h i g h c e l l u l o s e v i s c o s i t y a n d g o o d p a p e r s t r e n g t h ( P a s z n e r a n d B e h e r a , 1 985; B e h e r a , 1 9 8 5 ) . The b e h a v i o r o f e x t r a c t i v e s d u r i n g t h e s e o r g a n o s o l v p u l p i n g s t u d i e s h a s a p p a r e n t l y b e e n c o m p l e t e l y i g n o r e d t o d a t e . The e x t r a c t i v e s c o n t e n t o f o r g a n o s o l v p u l p s made f r o m s p r u c e ( B e h e r a , 1985) a n d D o u g l a s - f i r ( P a s z n e r a n d B e h e r a , 1985) c h i p s was f o u n d t o be l o w e r t h a n c u s t o m a r y f o r c h e m i c a l p u l p s ( k r a f t a n d s u l f i t e ) . F u r t h e r , no i n t e r f e r e n c e f r o m t h e d i s s o l v e d e x t r a c t i v e s was n o t e d d u r i n g l i g n i n a n d s o l v e n t r e c o v e r y . I n o t h e r w o r d s , t h e p r e s e n c e o f e x t r a c t i v e s d u r i n g o r g a n o s o l v p u l p i n g d i d n o t p r e s e n t a n y o f t h e common p u l p i n g p r o b l e m s ( h i g h c h e m i c a l c o m s u m p t i o n , i n h i b i t i o n o f d e l i g n i f i c a t i o n a n d p i t c h ) , n o r was t h e i r p r e s e n c e n o t a b l y i n t e r f e r i n g i n any way w i t h r e c o v e r y o f t h e b y - p r o d u c t s o r t h e a l c o h o l s o l v e n t . I t i s , t h e r e f o r e , a p p a r e n t t h a t t h e a l k a l i n e - e a r t h - s a l t - c a t a l y z e d o r g a n o s o l v p r o c e s s i s p a r t i c u l a r l y s u i t e d f o r p u l p i n g o f h i g h r e s i n c o n t e n t s o f t w o o d s a n d h a r d w o o d s . 15 2 .4. Effects of Wood Extractives on Pulping I t was s u g g e s t e d t h a t t h e e x t r a c t i v e s s u f f e r s e v e r a l c h a n g e s d u r i n g p u l p i n g ( S a n u s i e t a l . , 1 9 8 5 ) . They s t u d i e d t h e e f f e c t o f wood e x t r a c t i v e s on p u l p i n g a n d b l e a c h i n g o f r e d l a u a n by t h r e e p u l p i n g p r o c e s s e s . The r e d l a u a n c h i p s w e r e s u b j e c t e d t o k r a f t , a l k a l i - m e t h a n o l , a n d c r e s o l - w a t e r d i g e s t i o n s t o p r o d u c e c h e m i c a l p u l p s . T h e s e p r o c e s s e s were shown t o remove v a r y i n g p e r c e n t a g e s o f e x t r a c t i v e s as c o m p a r e d t o t h e c o l d e x t r a c t i o n b y e t h a n o l - b e n z e n e s o l v e n t s y s t e m (100%) f r o m t h e o r i g i n a l wood (See T a b l e 1 ) . Table 1. Extractives Removal by Different Pulping Systems (Sanusi et al., 1985) P u l p i n g m e t h o d E x t r a c t i v e s Removed (%) K r a f t 53 - 61 A l k a l i - m e t h a n o l 62 - 80 C r e s o l - w a t e r 78 - 90 16 T h e s e r e s u l t s showed t h a t t h e p r e s e n c e o f s o l v e n t s i n t h e c o o k i n g l i q u o r r e d u c e d t h e amount o f r e s i d u a l wood e x t r a c t i v e s i n t h e f i b e r s ( p u l p ) f o l l o w i n g c o o k i n g . From t h e p o i n t o f v i e w o f e f f i c i e n c y o f e x t r a c t i v e s r e m o v a l , t h e c r e s o l - w a t e r p u l p i n g was more e f f e c t i v e t h a n t h e k r a f t a n d a l k a l i - m e t h a n o l p r o c e s s e s , a l t h o u g h t h e f o r m e r p u l p s howed i n f e r i o r s t r e n g t h p r o p e r t i e s ( S a n u s i e t al., 1 9 8 5 ) . Thus t h e p u l p p r o p e r t i e s a n d r a t e s o f e x t r a c t i v e s r e m o v a l by t h e v a r i o u s s o l v e n t s may be u n r e l a t e d . T a c h i b a n a a n d Sumimoto (1982) s t u d i e d t h e c h e m i c a l c o m p o s i t i o n o f n e u t r a l e x t r a c t i v e s f r o m s e p e t i r p a y a (Pseudosindora palustris Sym.) a n d c o n c l u d e d t h a t t h e e x t r a c t i v e s f u n c t i o n e d as p h e n o l c a r r i e r s i n f o r m a t i o n o f c o l o r e d s p e c k s on p a p e r s h e e t s . They f o u n d t h a t t h e p h e n o l i c compounds, r e s p o n s i b l e f o r t h e c o l o r e d s p e c k s , w e r e p r o t e c t e d f r o m a l k a l i n e a t t a c k d u r i n g c o o k i n g by a membrane c o n t a i n i n g t h e s e n e u t r a l compounds . T a c h i b a n a a n d Sumimoto (1982) s u g g e s t e d t h a t t h e a g g r e g a t i o n o f p h e n o l i c s c a n be a i d e d by t h e e n c l o s i n g a c t i o n o f f i - s i t o s t e r y l g l u c o s i d e w h i c h i s a c c o m p a n i e d , o r o c c l u d e d by t h e n e u t r a l compounds. The 1 5 - s i t o s t e r y l g l u c o s i d e may a c t as i n t e r f a c i a l s u b s t a n c e b e t w e e n a r e s i n p a r t i c l e a n d t h e c o o k i n g l i q u o r a s i l l u s t r a t e d i n F i g . 1. G » a glucosidic part of fi-sitosteryl glucoside A - an aglycon part of fi-sitosteryl glucoside Figure 1. A model for phenol aggregates in neutral resin during kraft pulping of sepetir paya (Tachibana and Sumimoto, 1982) 18 According to McMillin (1969) i t i s not unreasonable to expect extractives present i n the pulp to have detrimental e f f e c t on pulp color and handsheet properties. He found that burst and tear strength of handsheets tend to decrease with increasing extractive content. This can be att r i b u t e d to a lessened bond strength owing to lowered surface tension forces, blocking of reactive s i t e s on the fi b e r surface, and the reduction of the number of the ef f e c t i v e hydrogen bonds. Detailed analysis by Tachibana and Sumimoto (1980) show that six phenolic extractives were responsible for the yellow specks that appear on the surface of bleached sulf a t e pulp. These new types of p i t c h problems were also i s o l a t e d from the wood of sepetir paya and i d e n t i f i e d as the following compounds: methyl ferulate (I), methyl p-coumarate (II), butein (III), pseudosindorin (IV) , sulphuretin (V) and rengasin (VI) (See F i g . 2) . Due to t h e i r conjugated structures these extractives would be expected to be highly colored due to the quinone methide products they are capable of forming under suitable conditions. These structures would also be expected to be susceptible to UV (photo) degradation. 19 C O O C H 3 I CH II CH O C H 3 OH Methyl fendate (I) HO HC II ^ C H OH - ^ - O H OH 0 But ein (III) C O O C H 3 I CH II CH OH Methyl p-coumarate (II) HO xx OH l OH HC-II •CH OH HO Psevdosindorin (IV) OH OH O H j Szdphuretin (V) H3CO « Rengasin (VI) Figure 2. Phenolic extractives responsible f o r the yellow specks from sepe t i r paya wood (Tachibana and Sumimoto, 1980) 20 2.5. Resin- and Fatty Acids 2.5.1. Background The r e s i n a n d f a t t y c o n s t i t u e n t s o f p u l p w o o d s a r e a v e r y i m p o r t a n t s o u r c e o f b y - p r o d u c t s . The r e s i n - a n d f a t t y a c i d s a r e t h e m a i n c o m p o n e n t s o f t h e t a l l o i l * o b t a i n e d f r o m t h e k r a f t p u l p i n g . The f a t t y a c i d f r a c t i o n i s c o m p o s e d o f e i t h e r s a t u r a t e d a n d / o r u n s a t u r a t e d e n t i t i e s . The most v a l u a b l e f a t t y a c i d c o m p o n e n t s o f t a l l o i l a r e t h o s e t h a t b e l o n g t o t h e u n s a t u r a t e d g r o u p ( d i e n o i c a n d t r i e n o i c a c i d s ) . Among t h e most common f a t t y a c i d s p r e s e n t i n wood a r e t h e f o l l o w i n g : p a l m i t i c ( C i g . g ) / s t e a r i c ( C ^ Q . Q ) , o l e i c ( C ] _ 8 : i ) f l i n o l e i c ( C J ^ Q ^ ) a n d l i n o l e n i c ( C i 8 : 3 ) * (See F i g . 3) . R e s i n a c i d s a r e o r g a n i c compounds t h a t b e l o n g t o t h e d i t e r p e n e g r o u p . D i t e r p e n e s , a r e compounds composed o f f o u r i s o p r e n e u n i t s ( S t r e i t w i e s e r a n d H e a t h c o c k , 1 9 8 1 ) . A l m o s t a l l t h e r e s i n a c i d s c a n be c l a s s i f i e d i n t o f o u r s k e l e t a l c l a s s e s : a b i e t a n e , p i m a r a n e , i s o p i m a r a n e a n d l a b d a n e . (See F i g . 4 ) . Among t h e s e r e s i n a c i d s t h e most * T a l l o i l c o n s i s t s o f a m i x t u r e o f 40 t o 5 0 % e a c h o f f a t t y a c i d s ( i . e . o l e i c a n d l i n o l e i c ) a n d r e s i n a c i d s ( i . e . a b i e t i c a n d p i m a r i c ) w i t h a b o u t 10% u n s a p o n i f i a b l e s . Hexadecanoic (pa lmi t ic ) acid -COOH Octadecanoic (stearic) acid .COOH Octadecaenoic (oleic) acid .COOH Octadecadienoic ( l inoleic) acid .COOH Octadecatr ienoic ( l inolenic) acid F i g u r e 3 . C h e m i c a l s t r u c t u r e s o f t h e m a j o r f a t t y a c i d s p r e s e n t i n s l a s h p i n e wood 22 18 A b i e t a n e L a b d a n e Figure 4. Main hydrocarbon skeletons f o r the r e s i n acids (Zinkel et al., 1971) 23 i m p o r t a n t a r e : p i m a r i c , s a n d a r a c o p i m a r i c , i s o p i m a r i c , l e v o p i m a r i c , p a l u s t r i c , d e h y d r o a b i e t i c , a b i e t i c a n d n e o a b i e t i c (See F i g . 5) . 2.5.2. Chemical Analysis of Resin- and Fatty Acids S i n c e t h e i n t r o d u c t i o n o f c h r o m a t o g r a p h y f o r s e p a r a t i o n b y T s w e t t i n 1906 t h e r e h a v e b e e n many c h a n g e s o r v a r i a t i o n s t o t h i s t e c h n i q u e . Among t h e m o d i f i c a t i o n s , p l a n e c h r o m a t o g r a p h y ( p a p e r a n d t h i n - l a y e r c h r o m a t o g r a p h y ( T L C ) ) , c o l u m n c h r o m a t o g r a p h y , g a s c h r o m a t o g r a p h y (GC) , a n d h i g h p e r f o r m a n c e l i q u i d c h r o m a t o g r a p h y (HPLC) a r e w i d e l y u s e d t o d a y . I t was a r o u n d 1952 t h a t t h e modern e r a o f c h r o m a t o g r a p h y b e g a n w i t h t h e p u b l i c a t i o n on t h e s e p a r a t i o n o f v o l a t i l e f a t t y a c i d s b y g a s - l i q u i d p a r t i t i o n c h r o m a t o g r a p h y (James a n d M a r t i n , 1 9 5 2 ) . The f i r s t g as c h r o m a t o g r a p h i c s t u d i e s were p e r f o r m e d on p a c k e d c o l u m n s . L a t e r w i t h t h e i n t r o d u c t i o n o f t h e open t u b u l a r c o l u m n s by G o l a y i n 1957, t h e s e became t h e most common c o l u m n s u s e d f o r s e p a r a t i o n a n a l y s i s (Freeman, 1981) . R e s i n - a n d f a t t y a c i d s p r e s e n t i n wood, b l a c k l i q u o r s a n d p u l p a n d p a p e r m i l l e f f l u e n t s h a v e b e e n c h a r a c t e r i z e d b y u s i n g a c o m b i n a t i o n o f c h r o m a t o g r a p h i c (TLC, GC a n d / o r HPLC) a n d s p e c t r o m e t r i c (UV, IR, NMR a n d / o r MS) 24 Palustrate Levopimarate Dehydroabietate Abietate Neoabietate Figure 5. Resin a c i d methyl esters of the abietane, pimarane, and isopimarane skeletons 25 techniques. Among the chromatographic techniques, gas l i q u i d chromatography (GLC or GC) i s the most widely used. Due to the excellent research and development c a r r i e d out by the suppliers, i t i s possible to obtain open tubular (capillary) columns i n sizes from 10 up to 100 m long, as reasonably strong, inert and durable tubing (fused-silica) and with cross-linked bonded-phases in order to avoid bleeding and to allow r i n s a b i l i t y of the columns. Nowadays, very complex samples can be e a s i l y separated by using these types of chromatographic columns. Different stationary phases have been studied for the separation of r e s i n - and f a t t y acids. A l i s t of the stationary phases used for packed columns i s as follows: 100% dimethyl polysiloxane (Zinkel, 1975), diethylene g l y c o l succinate or DEGS (Zinkel, 1975; Fourie and Basson, 1990), 10% S i l a r 10C (Leach and Thakore, 1976; Lie Ken J i e and Chan, 1985), ethylene g l y c o l - s i l i c o n e copolymer or EGSS-X (Zinkel and Foster, 1980; Zinkel and Han, 1986). Stationary phases used with c a p i l l a r y columns are: 100% dimethyl polysiloxane or SE-30 (Holmbom et al., 1974; Holmbom, 1977; Holmbom and Ekman, 1978; Lorbeer and K r a t z l , 1985), 95% dimethyl-(5%)-diphenyl-polysiloxane or SE-54 (Turner and Wallin, 1985; Ayorinde et al., 1988), 1,4-Butanediol succinate, BDS (Holmbom et al., 1974; Holmbom, 1977; Y i l d i r i m and Holmbom, 1977b; Holmbom and Ekman, 1978; Ekman, 1979; Anas et al., 1983; Zinkel and 26 Han, 1986) . Other stationary phases offered by the suppliers are: nitroterephthalate modified polyethylene g l y c o l (FFAP or SP-1000) and 50% cyanopropylmethyl-(50%)-methylphenyl-polysiloxane (DB-225). These were also used to analyze the fa t t y acids subject of the experiments of t h i s t h e s i s . Methyl esters are s t i l l the most universal derivatives for the gas chromatographic analysis of r e s i n -and f a t t y acids. The most popular d e r i v a t i z a t i o n techniques for methyl esters are: diazomethane, boron t r i f l u o r i d e , hydrochloric acid/methanol, s u l f u r i c acid/methanol, perchloric acid/methanol, and also t r a n s e s t e r i f i c a t i o n with either sodium methoxide i n methanol or tetramethylammonium hydroxide i n methanol (Fourie and Basson, 1990) . 2.5.3. Resin- and Fatty A c i d Characterization i n Wood and  Black Liquor Lately, the composition of the r e s i n - and fa t t y acids present i n softwoods has been f a i r l y completely established ( Y i l d i r i m and Holmbom, 1977b; Ekman, 1979; Lorbeer and Kra t z l , 1985). A n a l y t i c a l procedures for determining the r e s i n - and fa t t y acids present in wood might comprise a l l or some of the following steps: (a) i s o l a t i o n and concentration, (b) 27 separation and removal of neutral i n t e r f e r i n g substances, (c) methylation o f the r e s i n - and f a t t y acids, (d) i d e n t i f i c a t i o n and determination of the d i f f e r e n t components present i n the extract. Removal of the wood extractives has been performed by using d i f f e r e n t organic solvents. 7 A m o n g the most common solvents used for these extractions are: P e t r o l e u m e t h e r ( Y i l d i r i m and Holmbom, 1977b; Ekman, 1979; Lorbeer and Kra t z l , 1985), d i e t h y l e t h e r (Zinkel, 1975; Zinkel and Foster, 1980; Foster et a l . , 1980), a c e t o n e ( Y i l d i r i m and Holmbom, 1977a), m e t h a n o l (Lorbeer and K r a t z l , 1985) . According to Y i l d i r i m and Holmbom (1977b), the petroleum ether extractives of Pinus brutia Henry comprise around 1.1 to 1.5% o f the dry wood. Interesting findings were: i) the lack of pimaric acid (a re s i n acid) and i i ) the presence of o l e i c and l i n o l e i c acids as the major f a t t y acids. Kahila and Rinne (1957) demonstrated that changes in the r e s i n composition during storage of sprucewood were r e f l e c t e d i n the resin of the unbleached pulp as outlined i n F i g . 6. S u l f i t e pulping of both softwoods and some hardwoods (Kahila, 1957; Kahila and Rinne, 1957; Mutton 1958), may be i n h i b i t e d by t h e i r resins (Rydholm, 1985). Under acid pulping conditions, the fat t y and resi n acids are not o o 5 o c "55 <u cr 2.0r-1.5 1.0 0.5 nmol Glycerol^ . Fatty oeWT — •star* Fr** — W tzz fatty ' i z r n odds R*sln add* o.oL Wood Pulp Sprue* 4 month* seasoning Wood Pulp Sprue* 24 month* land ••atoning In Wood Pulp Sprue* 7 month* water Masoning I 1 11 Wood Pulp Sprue* 24 month* water seasoning - , 2.0 - 1.5 Unsopo— — ntfiables ^ — Glycerol Fatty " add •ster* Fr** — fatty acids 1.0 0.5 0.0 Wood Pulp Birch no Figure 6 . Dissolution and composition changes of ether extractives on aci d s u l f i t e pulping of spruce, seasoned by d i f f e r e n t methods, and of green birchwood (Kahila, 1957) 29 c o n v e r t e d i n t o h y d r o p h i l i c s o a p s a s i s t h e c a s e i n a l k a l i n e p u l p i n g ( Rydholm, 1985) . I t h a s b e e n p o i n t e d o u t ( K a h i l a , 1957, K a h i l a a n d R i n n e , 1957) t h a t t h e amount o f r e s i n a c i d s d e c r e a s e s d u r i n g t h e s u l f i t e c o o k i n g p r o c e s s . I t a l s o seems t h a t t h e amount o f u n s a p o n i f i a b l e m a t t e r i n t h e e x t r a c t s d e c r e a s e s t o a c o n s i d e r a b l y l e s s e r d e g r e e (See F i g . 6) . F u r t h e r m o r e , t h e y f o u n d t h a t t h e c o n t e n t o f u n s a t u r a t e d C 16-18 f a t t y a c i d s , c o n t a i n i n g two d o u b l e b o n d s ( i . e . l i n o l e i c a c i d ) d e c r e a s e s c o n s i d e r a b l y a s c o m p a r e d w i t h t h e o l e i c a c i d . On t h e o t h e r h a n d , s a t u r a t e d f a t t y a c i d s r e m a i n l a r g e l y u n c h a n g e d d u r i n g t h e c o o k ( F i g . 7 ) . L o r b e e r a n d K r a t z l (1985) when w o r k i n g w i t h t h e A u s t r i a n b l a c k p i n e {Pinus nigra v a r . A u s t r i a c a ) , e x a m i n e d t h e d i f f e r e n c e b e t w e e n t h e r e m o v a l o f t h e wood e x t r a c t i v e s w i t h m e t h a n o l a n d p e t r o l e u m e t h e r . They f o u n d t h a t d u r i n g t h e e x t r a c t i o n w i t h m e t h a n o l , e s t e r i f i c a t i o n o f t h e f r e e f a t t y a c i d s t o o k p l a c e , a s o p p o s e d t o t h e non r e a c t i v i t y o f t h e r e s i n a c i d s . They a l s o r e p o r t e d t h a t t h e r e was no i s o m e r i z a t i o n o f t h e c o n j u g a t e d f a t t y a c i d s d u r i n g t h e t r e a t m e n t w i t h m e t h a n o l o v e r d i f f e r e n t l e n g t h s o f t i m e . A c c o r d i n g t o Holmbom a n d Ekman ( 1 9 7 8 ) , t h e c o n t e n t o f t h e t a l l o i l p r e c u r s o r s i n common s p r u c e [Picea abies (L.) K a r s t ] was a b o u t 30 t o 5 0 % o f t h a t o f S c o t s p i n e {Pinus s i l v e s t r i s L . ) . They f o u n d t h a t d u r i n g k r a f t p u l p i n g , t h e TJ O o Q) O D l_ QL (0 o to* 'o D 00 r (£) O 0.30 r-0.20 0.10 0.00 0=Saturated acids 1 =Monounsaturated acids 2=Diunsaturated acids 3=Triunsaturated acids 0 Wood Pu lp Wood Pulp S p r u c e S p r u c e 4 M o n t h s l a n d s e a s o n i n g 8 m o n t h s l and s e a s o n i n g 0 Wood Pu lp S p r u c e 7 m o n t h s w a t e r s e a s o n i n g 1 0 7ZZ2. -1 1.00 0.75 0.50 0.25 0.00 Wood Pu lp B i r c h n o s e a s o n i n g O O o o &^  to TJ 'o O OO r O U) o Figure 7. Changes in the Cjg.jg fatty acid composition of spruce and birch on acid s u l f i t e pulping after different types of seasoning (Kahila and Rinne, 1957) 31 d i e n o i c a n d t r i e n o i c f a t t y a c i d s a r e i s o m e r i z e d t o a c i d s w i t h c o n j u g a t e d d o u b l e b o n d s o f t h e c i s - t r a n s c o n f i g u r a t i o n t y p e . F u r t h e r , t h e y f o u n d t h a t t h e m a i n c h a n g e i n t h e r e s i n a c i d c o m p o s i t i o n d u r i n g p u l p i n g was t h e i s o m e r i z a t i o n o f l e v o p i m a r i c i n t o a b i e t i c a c i d . D a t a o f Z i n k e l (1975) on t h e e x t r a c t i v e s o f l o b l o l l y p i n e wood ( P i n u s taeda L.) a n d i n t h e b l a c k l i q u o r a f t e r k r a f t p u l p i n g i s p r e s e n t e d i n T a b l e s 2, 3 a n d 4. D u r i n g t h e i r c h r o m a t o g r a p h i c a n a l y s e s , t h e y w e re u n a b l e t o r e s o l v e p r o p e r l y l e v o p i m a r i c a n d p a l u s t r i c a c i d s when u s i n g DEGS o r S E - 3 0 / E g i P as s t a t i o n a r y p h a s e s . The d a t a a r e p r e s e n t e d as a c o m b i n e d f i g u r e i n T a b l e 3. A n a l y s i s o f t h e n o n s a p o n i f i a b l e f r a c t i o n showed t h a t t h e m a i n c o m p o n e n t s were s i t o s t e r o l ( 4 8 % o f t o t a l n o n s a p o n i f i a b l e s ) , t r a n s - p i n o s y l v i n d i m e t h y l e t h e r ( 8 . 3 % ) , t e t r a c o s a n o l ( 2 . 5 % ) , p i m a r a l ( 2 . 3 % ) , p i m a r o l (2.4%) a n d a g a t h a d i o l (0.7%) ( Z i n k e l , 1 9 7 5 ) . Z i n k e l a n d F o s t e r (1980) d e t e r m i n e d t h e c o m p o s i t i o n o f t h e t a l l o i l p r e c u r s o r s i n t h e s a p w ood a n d b l a c k l i q u o r s a f t e r k r a f t p u l p i n g o f f o u r s o u t h e r n p i n e woods: s l a s h (Pinus e l l i o t t i i E n g e l m . ) , l o n g l e a f (Pinus p a l u s t r i s M i l l . ) , s h o r t l e a f (Pinus echinata M i l l . ) , a n d V i r g i n i a (Pinus v i r g i n i a n a M i l l . ) p i n e s (See T a b l e s 5, 6 a n d 7 ) . They f o u n d t h a t d u r i n g k r a f t p u l p i n g o f t h e s e s p e c i e s i s o m e r i z a t i o n r e a c t i o n s a n d s i g n i f i c a n t l o s s e s o f t h e r e s i n a n d f a t t y a c i d s r e s u l t e d . The l o s s e s w e r e shown t o 32 Table 2. Extractives of L o b l o l l y Pine Wood and Black Liquor (Zinkel, 1975) E x t r a c t , mg/g of o.d. wood Et h e r s o l u b l e Black e x t r a c t i v e s Wood L i q u o r T o t a l e x t r a c t 20.0 19 .7 N e u t r a l s 14 .9 2 .5 S a p o n i f i a b l e 12.2 N o n s a p o n i f i a b l e s 2.2 2.5 G l y c e r o l 0.3 a 0.3 a Free a c i d s 5.0 17.0 R e s i n 3.9 3.6 F a t t y 0.3 12 . 4 O x i d i z e d 1. 0 0.9 Strong 0.1 0.2 T o t a l f a t t y a c i d s 12.0 12 . 4 Not accounted f o r 0.2 a = C a l c u l a t e d assuming a l l wood s a p o n i f i a b l e s are t r i g l y c e r i d e s . Table 3 . Resin acids of l o b l o l l y pine wood (Zinkel, 1975) Black R e s i n a c i d Wood, Li q u o r , methyl e s t e r % % Pimarate 8.0 7.7 Sandaracopimarate 1.8 1.8 Communate t r . ? . . L e v o p i m a r a t e - p a l u s t r a t e 59.5 45 . 1 Isopimarate 1 . 6 1.3 A b i e t a t e 12. 6 19.2 Dehydroabietate 8 . 4 14 . 6 Neoabietate 8.1 10.4 Table 4. Fatty Acids of L o b l o l l y Pine Wood (Mole % ) ( Z i n k e l 1975) F a t t y a c i d M e t h y l e s t e r 3 r 1 8 : 0 Free E s t e r i f i e d B l a c k L i q u o r U n s a t u r a t i o n 14 :0 0.33 1.9 t r t r U 0 .43 0.7 t r t r U 0.50 t r t r t r 16 :0 0.57 20 .9 6.4 6 . 1 1 6 : 1 0 .67 3 .6 1.1 1.0 17 :0? 0.74 1.3 # # t r U 0.88 t r t r t r 18 :0 1.00 24 .2 2 .0 1.8 1 8 : 1 1.18 15.0 39 .7 38 .4 9 c U 1.30 0.7 0.7 0 .7 18 :2 1.45 10.8 39 .2 2 3 . 7 9, 12 cc 18 :3 1.64 3 .6 3 .6 1.2 5, 9, 12 U 1.75 1.5 1.0 * . 18 :2 1.94 • • • • 15 .0 9, 11 c t U 2 . 1 1 • • • • 2 . 5 18 :2 2 .23 • • 1.9 9, 11 ? U 2 .44 • • • • 1.3 2 0 : 3 2 .80 0.0 4 .7 3 .5 5, 1 1 , 14 2 2 : 0 3 .19 10.2 0 .8 U 3 .66 • • 1.1 2 4 : 0 5 .70 10.0 0 .8 a U , u n i d e n t i f i e d ; t r , t r a c e . Table 5. Fatty acid composition of southern pine sapwood and kraft black liquor. (Zinkel and Foster 1980) F a t t y a c i d ( n o r m a l i z e d % o f f r a c t i o n ) P i n e s f a t t y a c i d 16 :0 1 6 : 1 17 :0 18:0 1 8 : 1 1 8 : 2 9 ' 1 2 1 8 : 3 5 ' 9 ' 1 2 1 8 : 3 9 ' 1 2 ' 1 5 1 8 : 2 9 ' n f r a c t i o n S l a s h Free 11 .6 0 .8 1.6 3 .5 3 2 . 1 3 0 . 1 2 . 3 1.6 E s t e r i f i e d 6 .9 0 .3 1.1 1.7 42 .8 36 .3 2 . 7 1.4 B l a c k l i q . 6.4 0 .4 0.7 1.2 42 .9 2 4 . 1 1.1 1.4 12 . l a L o n g l e a f F ree 8 .3 0 .6 1.2 3 .6 37 .6 34 .2 4 .0 0 .9 • • E s t e r i f i e d 4 . 9 0 .3 0 .6 0.8 40 .8 39 .6 2 . 9 1.3 » • • B l a c k l i q . 5 .0 0 .3 0.7 1.1 42 .6 2 7 . 1 1 .1 1.3 10 5 S h o r t l e a f F r e e b 14 .9 0 .7 0 .9 3 .3 33.4 2 5 . 2 2 . 0 0 .5 • • E s t e r i f i e d 6 .3 0 .3 1.0 1.2 32 .4 4 1 . 9 5 .2 0 .8 • • B l a c k l i q . 6.7 0 .2 1.8 1.6 34 .3 2 5 . 5 2 . 4 0 .8 13 5 V i r g i n i a F r e e c 16.7 1.5 1.2 4 .4 15.7 2 4 . 5 3 . 1 0 .9 E s t e r i f i e d 4 . 9 0 .4 0 .9 1.0 30 .2 4 4 . 1 9.3 1.5 • • B l a c k l i q . 4 . 7 0.4 0 .6 1.1 30 .2 20 .4 2 . 3 1.5 19 6 a= The 1 8 : 3 9 ' 1 2 ' 1 5 (a 18 ca rbon f a t t y a c i d w i t h 3 d o u b l e bonds o c c u r r i n g a t bond p o s i t i o n s 9, 12/ and 15) and 1 8 : 2 9 ' 1 : L peaks were n o t r e s o l v e d on GLC. The 1 8 : 2 9 ' 1 3 - was e s t i m a t e d by s u b t r a c t i n g t h e 1 8 : 3 9 ' ^ 2 / ^ ^ c o n t e n t f o u n d i n t h e e s t e r i f i e d f r a c t i o n f r o m t h e combined peak o f t h e b l a c k l i q u o r . b= c o n t a i n e d 12.8% 2 0 : 0 . c= C o n t a i n e d 3.8%, 8.8% and 7.0% o f 2 0 : 0 , 22 :0 and 2 4 : 0 , r e s p e c t i v e l y . Table 6. Resin acids of slash pine sapwood and k r a f t black l i q u o r (Zinkel and Foster, 1980) Slash Shortleaf Longleaf V i r g i n i a Black Black Black Black Resin acids* Wood l i q . Wood l i q . Wood l i q . Wood l i q . % % % % % % % % P i m a r a t e 7.4 7.7 6.0 6.4 6.6 7.4 6.3 6.8 S a n d a r a c o p i m a r a t e 2.0 2.4 1.8 2.2 2.0 2.0 1.4 1.9 Communate 2.7 2.1 — . -L e v o p i m a r a t e 9.6 3.7 27 . 9 12.7 27.8 12.0 34.6 17.7 P a l u s t r a t e 19.4 19.3 15.2 26.5 19.0 27.5 12.0 14.9 I s o p i m a r a t e 23.7 26.2 5.0 5.7 8.3 8.3 3.5 4.9 A b i e t a t e 12.0 13.2 15.1 14.7 13.5 15.7 17.1 22.0 D e h y d r o a b i e t a t e 4.8 8.8 15.3 16.6 10.5 12.8 2.6 6.1 N e o a b i e t a t e 18.4 16.5 13.7 15.2 12.1 14.2 22.5 25. 6 * R e s i n a c i d s were d e t e r m i n e d as t h e i r m e t h y l e s t e r s . Table 7 . Composition of the t a l l o i l precursors of southern pine sapwood and kraft black l i q u o r extractives (mg/g of o.d. extractives-free wood). (Zinkel and Foster, 1980) S l a s h S h o r t l e a f L o n g l e a f V i r g i n i a E t h e r - s o l u b l e B l a c k B l a c k B l a c k B l a c k e x t r a c t i v e s Wood l i q u o r Wood l i q u o r Wood l i q u o r Wood l i q u o r N e u t r a l s ( s a p o n i f i e d ) 20.1 1.4 20.1 1.2 22.7 1.4 10.6 1. 0 F a t t y a c i d s 17. 6 18.3 20.3 9.5 N o n s a p o n i f i a b l e s 2.5 1.4 1.8 1.2 2.4 1.4 1.1 1.0 F r e e a c i d s 5.9 20.4 6.6 22.5 6.0 24.9 3.4 11.5 R e s i n 5.7 3.5 6.5 4.4 5.8 4.7 3.3 2.9 T o t a l f a t t y a c i d s 17.8 16.9 18.4 18 .1 20.5 20.2 9.6 8.6 T o t a l t a l l o i l p r e c u r s o r s 8 26.0 21.8 26.7 23. 6 28.7 26.1 14.0 12.5 a T a l l o i l p r e c u r s o r s = t o t a l f a t t y a c i d s + r e s i n a c i d s + n o n s a p o n i f i a b l e s 37 be r e p r o d u c i b l e b e t w e e n r e p e t i t i v e e x p e r i m e n t s , a n d o n l y 80 t o 90 % o f t h e o r i g i n a l t a l l o i l p r e c u r s o r s were r e c o v e r e d f r o m t h e b l a c k l i q u o r s . I t c a n be s e e n f r o m t h e d a t a i n T a b l e 6 t h a t t h e r e s i n a c i d c o m p o s i t i o n o f t h e s e f o u r p i n e s i s q u i t e s i m i l a r . S l a s h p i n e was a n o t i c e a b l e e x c e p t i o n b e c a u s e o f i t s r e l a t i v e l y h i g h p r o p o r t i o n o f i s o p i m a r i c a c i d a n d l o w f r a c t i o n o f l e v o p i m a r i c a c i d . F o s t e r e t al. ( 1 9 8 0 ) , c h a r a c t e r i z e d t h e sapwood a n d h e a r t w o o d e x t r a c t s o f D o u g l a s - f i r [Pseudotsuga menziesii ( M i r b . ) F r a n c o ] a n d t h e t a l l o i l f r o m t h e k r a f t b l a c k l i q u o r . They f o u n d t h a t t h e y i e l d o f h e a r t w o o d d i e t h y l e t h e r e x t r a c t i v e s , (mg/g o v e n - d r i e d e x t r a c t - f r e e ( o . d . e . f . ) wood b a s i s ) was n e a r l y t h r e e t i m e s t h a t o f t h e s a p w ood (See T a b l e 8 ) , a n d t h a t t h e amount o f t a l l o i l p r e c u r s o r s was o n l y 80% o f t h a t o f sapwood. F u r t h e r m o r e , t h e y r e p o r t e d t h a t d u r i n g k r a f t p u l p i n g , i s o m e r i z a t i o n r e a c t i o n s a n d a r e d u c t i o n o f t h e t o t a l a mounts o f c o n j u g a t e d r e s i n a c i d s , w i t h f o r m a t i o n o f d e h y d r o a b i e t i c a c i d o c c u r . F o s t e r e t a l . ' s (1980) t a l l o i l p r e c u r s o r c o n t e n t was l o w e r by a b o u t 15% t h a n t h a t r e p o r t e d by Z i n k e l e t al. (1980) f o r s o u t h e r n p i n e s . T h e r e f o r e , u n d e r a c i d o r a l k a l i n e c o n d i t i o n s , c o n s i d e r a b l e t r a n s f o r m a t i o n o f t h e e x t r a c t i v e c o m p o n e n t s c a n be e x p e c t e d . S u c h c h a n g e s a l t e r t h e i r c h e m i c a l a n d p h y s i c a l c h a r a c t e r i s t i c s . T h e s e c h a n g e s may be b e n e f i c i a l Table 8. Extractives of Douglas-fir wood and black l i q u o r (Foster et al., 1980) Extractives, mg/g of o.d. wood Sapwood Heartwood Black Black Wood3 Liquor Wood3 Liquor Neutrals . . .Non-saponifiables . . .Saponifiables (fatty acids) . . .Not recovered 1 3 5.5 1.7 3.5 0.3 0.7 0.7 7.0 1.6 1.6 3.8 1.1 1.1 Free Acids . . .Fatty acids . . .Resin acids 2.1 0.1 2.0 2.6 1.4 1.2 2.8 0.1 2.7 2.2 0.7 1.4 Strong acids 0.1 t r . 0.1 0.1 T a l l o i l precursors 0 7.3 3.3 6.0 3.3 a) Total die t h y l ether extractives from sapwood was 7.7 mg/g, and from heartwood 21.2 mg/g (11.3 mg/g was not eluted from DEAE-Sephadex by acetic acid). b) Not recovered from saponification. c) T a l l o i l precursors = non-saponified neutrals and saponified neutrals and free acids. 39 t e c h n i c a l l y (by-products) or detrimental environmentally ( t o x i c i t y and p o l l u t i o n ) . 2.5.4. Characterization of Resin- and Fatty Acids i n Pulp  and Paper M i l l E f f luents Resin- and f a t t y acids (RAFA) have been established to be the major contributors to f i s h t o x i c i t y by softwood pulp and paper m i l l effluents (Rogers et al., 1972; Rogers, 1973; Leach and Thakore, 1973; Leach and Thakore, 1976; Leach et al., 1978; Chung et al., 1979; Holmbom, 1980; Walden and Howard, 1981; Wearing et al., 1984; Sameshima et a l . , 1986). Control of these compounds in the discharges from pulp and paper m i l l s i s important in c o n t r o l l i n g t h e i r impact on the environment and assessing t h e i r b i o l o g i c a l e f f e c t . The effectiveness of the control measures depends on the a v a i l a b i l i t y of adequate a n a l y t i c a l methods. Several investigators have been using high performance l i q u i d chromatography (HPLC) for the analysis of r e s i n - and fa t t y acids (RAFA) i n pulp m i l l effluents and/or t a l l o i l rosins (Mortimer, 1979; Fatica, 1989). However, analysis by gas chromatography s t i l l remains the selected choice for the characterization of RAFA constituents i n pulp and paper m i l l e f f l u e n t s as described 40 b y Holmbom ( 1 9 7 7 ) , Chung et al. ( 1 9 7 9 ) , Holmbom ( 1 9 8 0 ) , T u r o s k i ( 1 9 8 1 ) , V o s s a n d R a p s o m a t i o t i s ( 1 9 8 5 ) . A l m o s t a l l o f t h e e f f o r t s f o r t h e a n a l y s i s o f t h e p u l p a n d p a p e r m i l l e f f l u e n t s i n N o r t h A m e r i c a h a v e b e e n d e v e l o p e d i n t h e USA ( N a t i o n a l C o u n c i l o f t h e P a p e r I n d u s t r y f o r A i r a n d S t r e a m Improvement - NCASI) a n d C a n a d a ( B r i t i s h C o l u m b i a R e s e a r c h - BCR) . The m a i n d i f f e r e n c e b e t w e e n t h e s e two p r o c e d u r e s (NCASI a n d BCR) i s t h e m e t h o d o f i s o l a t i o n . The NCASI p r o c e d u r e u s e s d i e t h y l e t h e r a s t h e s o l v e n t f o r e x t r a c t i o n o f an a c i d i f i e d (pH 2 - 3) e f f l u e n t , w h i l e t h e BCR p r o c e d u r e r e m o v e s t h e r e s i n -a n d f a t t y a c i d s f r o m t h e e f f l u e n t u n d e r a l k a l i n e (pH 9-10) c o n d i t i o n s b y a d s o r p t i o n o n t o a p o r o u s " p o l y m e r i c r e s i n " (XAD-2) ( V o s s a n d R a p s o m a t i o t i s , 1 9 8 5 ) . M o s t o f t h e l a t e s t i n n o v a t i o n s i n a n a l y t i c a l m e t h o d s f o r t h e c h a r a c t e r i z a t i o n o f RAFA p r e s e n t i n p u l p a n d p a p e r m i l l e f f l u e n t s h a v e b e e n d i r e c t e d t o t h e i r c h r o m a t o g r a p h i c s e p a r a t i o n a n d d e t e c t i o n . I n t h i s r e g a r d , t h e most i m p o r t a n t d e v e l o p m e n t s h a v e b e e n t h e u s e o f h i g h -r e s o l u t i o n c a p i l l a r y g a s c h r o m a t o g r a p h y (Chung e t al., 1979; Holmbom, 1980) a n d t h e c o m b i n a t i o n o f g a s c h r o m a t o g r a p h y a n d mass s p e c t r o m e t r y (GC-MS) ( T u r o s k i e t al., 1 9 8 1 ; C l a e y s e t al., 1 9 8 3 ) . The i s o l a t i o n o f r e s i n - a n d f a t t y a c i d s f r o m p u l p a n d p a p e r m i l l e f f l u e n t s i s t h e most i m p o r t a n t a n d c r i t i c a l s t e p d u r i n g a g i v e n p r o c e d u r e . I t d e f i n e s t h e maximum 41 recovery of the analytes of int e r e s t ; as well i t can l i m i t the amount of co-extractives that might i n t e r f e r e with t h e i r quantitative determination. I s o l a t i o n can be performed either by adsorption onto a porous "polymeric r e s i n " or by solvent extraction using a single solvent or a combination of solvents. Among the "polymeric resins" used for i s o l a t i o n of r e s i n - and fa t t y acids from the effluents, only three of them have been found to be of great i n t e r e s t and these resins are: XAD-2 (Rogers, 1973; Leach and Thakore, 1976; Rogers et al., 1979; Chung et al., 1979; Wearing et al., 1984; Voss and Rapsomatiotis, 1 9 8 5 ) , XAD-4 (Rogers et al., 1979) and XAD-8 (Button, 1 9 7 1 ) . Out of these three polymeric resins, XAD-2 i s the most commonly used for r e s i n - and f a t t y acids analysis i n pulp and paper m i l l e f f l u e n t s . Several solvents or mixtures have been suggested for solvent extraction of the r e s i n - and fa t t y acids from black liquors and pulp and paper m i l l e f f l u e n t s . The most important solvents are as follows: Petroleum ether-acetone-methanol (Saltsman and Kuiken, 1959; McMahon, 1980) ; d i e t h y l ether (Anon. NCASI, 1972; Anon. NCASI, 1 9 7 5 ; Holmbom, 1 9 8 0 ) ; methylene chloride (Turoski et a i . , 1 9 8 1 ; Turner and Wallin, 1 9 8 5 ) ; hexane-acetone-methanol (Wearing et a l . , 1 9 8 4 ) ; methyl t e r t - b u t y l ether (Voss and Rapsomatiotis, 1 9 8 5 ) . 42 Several problems have been encountered during the removal of the r e s i n - and fa t t y acids from the black liquors and m i l l e f f l u e n t s . Among the most common ones are the p r e c i p i t a t i o n of the l i g n i n and formation of emulsions during the extraction steps where a c i d i f i e d l i g n i n fragments are present. These residues may induce the adsorption of the r e s i n - and fa t t y acids leading to erroneously low r e s u l t s . McMahon (1980) using a ternary solvent system (petroleum ether-acetone-methanol) solved t h i s problem by keeping the l i g n i n i n solution; no loss of r e s i n - and fa t t y acids took place because no emulsion was formed. Emulsion d i f f i c u l t i e s have been addressed i n di f f e r e n t ways. Voss and Rapsomatiotis (1985) eliminated t h i s problem by adding equal or greater amounts of methyl t e r t - b u t y l ether to the effluents during t h e i r extraction procedure. Turoski et al. ( 1 9 8 1 ) , when extracting an a c i d i f i e d (pH 2) effluent sample with dichloromethane, found severe emulsion d i f f i c u l t i e s which were broken primarily by using a heat gun to gently b o i l the dichloromethane i n the bottom layer of the separatory funnel. When a l l else f a i l e d , the entire emulsion interface was either f i l t e r e d or drawn o f f and centrifuged. To obtain phase separation Turner and Wallin (1985) used ultr a s o n i c dispersion for breaking up emulsions. 43 I n a d d i t i o n t o t h e p r o c e d u r e s m e n t i o n e d a b o v e f o r t h e c h a r a c t e r i z a t i o n o f r e s i n - a n d f a t t y a c i d s b y g a s c h r o m a t o g r a p h y a n d / o r g a s c h r o m a t o g r a p h y - m a s s s p e c t r o m e t r y , some p r o c e d u r e s i n v o l v e c o l o r i m e t r i c t e c h n i q u e s f o r t h e d e t e r m i n a t i o n o f t h e r e s i n a n d / o r f a t t y a c i d s . M c D o n a l d (1978) r e p o r t e d on t h e q u a n t i t a t i v e d e t e r m i n a t i o n o f t h e a b i e t i c - t y p e r e s i n a c i d s p r e s e n t i n k r a f t e f f l u e n t s . He f o u n d t h a t t h e r e c o v e r y o f t h e s e a c i d s b y e x t r a c t i o n was n o t q u a n t i t a t i v e , b u t c o u l d be c a l c u l a t e d f o r a g i v e n s e t o f c o n d i t i o n s a n d t h e a n a l y t i c a l r e s u l t s a d j u s t e d a c c o r d i n g l y . The m a i n d r a w b a c k o f t h i s m e t h o d i s t h e i n t e r f e r e n c e o f u n s a t u r a t e d f a t t y a c i d s a n d s t e r o l s commonly p r e s e n t i n p u l p a n d p a p e r m i l l e f f l u e n t s . Kwon a n d Rhee (1986) d e v e l o p e d a s i m p l e a n d r a p i d c o l o r i m e t r i c m e t h o d f o r d e t e r m i n i n g t h e f r e e f a t t y a c i d s p r o d u c e d b y l i p a s e f r o m t r i a c y l g l y c e r i d e s . T h e i r m e t h o d u s e d a c u p r i c a c e t a t e - p y r i d i n e m i x t u r e as a c o l o r d e v e l o p i n g r e a g e n t . The s e n s i t i v i t y a n d r e p r o d u c i b i l i t y o f t h i s m e t h o d was g o o d f o r c a p r o i c , c a p r y l i c , c a p r i c , l a u r i c , p a l m i t i c , s t e a r i c a n d o l e i c a c i d s . A n o t h e r s p e c t r o p h o t o m e t r y d e t e r m i n a t i o n o f f a t t y a c i d s a s a new a s s a y f o r l i p a s e s i s p r o p o s e d b y Walde (1990) . T h i s s i m p l e m e t h o d f o r f a t t y a c i d d e t e r m i n a t i o n s i n v e g e t a b l e s o i l s c a n be c a r r i e d o u t w i t h s a m p l e s o f l e s s t h a n 100 mg. 44 2.6. U t i l i z a t i o n of Extractives Wood e x t r a c t i v e s c o m p r i s e a l a r g e number o f c h e m i c a l e n t i t i e s w h i c h h a v e b e e n u t i l i z e d f o r d i f f e r e n t p u r p o s e s , e . g . d y e s , t a n n i n g a g e n t s a n d p e r f u m e s , o r n a v a l s t o r e s ( F e n g e l a n d Wegener, 1 9 8 4 ) . C u r r e n t l y , e x t r a c t i v e s o f wood a n d b a r k a r e v a l u a b l e s o u r c e s o f p h e n o l s f o r t h e m a n u f a c t u r e o f n a t u r a l l y b a s e d p h e n o l - f o r m a l d e h y d e a d h e s i v e s a n d o f s p e c i a l p r o d u c t s d e r i v e d f r o m t h e m a i n wood c o m p o n e n t s . D i v i s i o n o f t h e e x t r a c t i v e s p r e s e n t i n l i v i n g t r e e s , wood, b a r k a n d f o l i a g e c a n be f o r m u l a t e d a s f o l l o w s : 1. B a r k e x t r a c t i v e s o b t a i n e d b y s o l v e n t e x t r a c t i o n . 2. Wood e x t r a c t i v e s o b t a i n e d b y means o f s o l v e n t e x t r a c t i o n o r p u l p i n g ( e . g , k r a f t ) . 3. F o l i a g e e x t r a c t i v e s . /An o v e r v i e w o f t h e s e l o w - m o l e c u l a r - w e i g h t s i l v i c h e m i c a l s i s g i v e n i n F i g . 8 ( F e n g e l a n d Wegener, 1984) . E x t r a c t i v e s p r e s e n t i n t h e f o l i a g e h a v e l o n g b e e n u s e d f o r t h e i r m e d i c i n a l , n u t r i t i v e a n d r e l a x a n t v a l u e s . The e s s e n t i a l o i l s t h a t c a n be e x t r a c t e d b y s t e a m d i s t i l l a t i o n o f f o l i a g e a r e p r i m a r i l y u s e d i n t h e p r e p a r a t i o n o f f r a g a n c e s , p e r f u m e s a n d c o s m e t i c s ( K e a y s , 1976) . Rosin Turpentine ^ ^ S t u m p extract ion j TREE j Topping ^ > Rosin Turpentine Maple syrup Solvent extract ion Solvent ext ract ion Tannins Phenolic acids Waxes Tannins Terpenes Lignans Colouring mat te r Figure 8. Chemical products derivable from extractives (Fengel and Wegener, 1984) 46 E x t r a c t i v e s p r e s e n t i n p u l p - m i l l w a s t e l i q u o r s a l s o d e s e r v e a t t e n t i o n b o t h b e c a u s e o f t h e i r i m p o r t a n c e i n w a s t e t r e a t m e n t a n d f o r t h e i r i n s e c t i c i d a l ( t o x i c ) e f f e c t s ( S a m e s h i n a e t al., 1980; S a m e s h i n a e t al., 1 9 8 6 ) . S e v e r a l p u l p i n g w a s t e - l i q u o r s h a v e b e e n r e p o r t e d t o h a v e t e r m i t i c i d a l a c t i v i t y ( S a m e s h i n a e t al., 1978 ; S a m e s h i n a e t al., 1980) o r i n h i g h e n o u g h c o n c e n t r a t i o n s t o b e t o x i c t o f i s h ( S a m e s h i n a et al., 1 9 8 6 ) . V e r y i m p o r t a n t b y - p r o d u c t s f r o m k r a f t p u l p i n g a r e s u l f a t e t u r p e n t i n e a n d t a l l o i l w h i c h a r e u s e d i n t h e p a i n t a n d l a c q u e r i n d u s t r y a n d f o r some o t h e r p u r p o s e s ( S j o s t r o m , 1 9 8 1 ) . T a l l o i l c o n s i s t s o f a m i x t u r e o f 4 0 - 5 0 % e a c h o f f a t t y a c i d s ( i . e . o l e i c a n d l i n o l e i c ) a n d r e s i n a c i d s w i t h a b o u t 10 % u n s a p o n i f i a b l e s . M o s t o f t h e c r u d e t a l l o i l i s p u r i f i e d a n d f r a c t i o n a t e d b y v a c u u m d i s t i l l a t i o n t o y i e l d a f a t t y a c i d f r a c t i o n a n d a r e s i n a c i d f r a c t i o n ( S j o s t r o m , 1 9 8 1 ) . (See F i g . 9 ) . The mos t i m p o r t a n t f i e l d s o f a p p l i c a t i o n s f o r t h e f a t t y a c i d s a r e : s o a p s , e s t e r s , f a t t y a l c o h o l s , a m i n e s , m e t a l s o a p s , e m u l s i f i e r s , p o l y o l e s t e r s , a m i d e s , a d d i t i v e s f o r p l a s t i c s a n d o t h e r s ( K n a u t a n d R i c h t l e r , 1 9 8 5 ) . C u r r e n t l y , a n o v e r s u p p l y o f f a t t y a c i d s e x i s t s due t o t h e f a c t t h a t w o r l d demand f o r f a t t y a c i d m e t h y l e s t e r s h a s d e c l i n e d i n r e c e n t y e a r s . M e t h y l e s t e r d e r i v a t i v e s h a v e b e t t e r s t o r a g e s t a b i l i t y ; t h e y a r e r e a d i l y f r a c t i o n a t e d due t o t h e i r l o w e r b o i l i n g p o i n t ; t h e y r e q u i r e l e s s 47 Figure 9. Main d i s t i l l a t e s from crude t a l l o i l a f t e r a c i d i f i c a t i o n (Sj6str6m, 1981) 48 e n e r g y f o r t h e i r p r o d u c t i o n , a n d a r e l e s s c o r r o s i v e . On t h e o t h e r h a n d , t h e i n v e s t m e n t c o s t s a s s o c i a t e d w i t h t h e i r p r o c e s s i n g a r e h i g h e r t h a n f o r t h e f a t t y a c i d s ( K n a u t a n d R i c h t l e r , 1985) . Numerous s t u d i e s h a v e b e e n c o n d u c t e d i n t h e U n i t e d S t a t e s on t h e p o t e n t i a l u s e o f f a t s a n d o i l s a s f u e l f o r f a r m e q u i p m e n t a n d t r u c k s . T h e s e s t u d i e s d e m o n s t r a t e d t h a t t h i s i s an a t t r a c t i v e a p p l i c a t i o n i n p r i n c i p l e a n d f r o m a m a r k e t v i e w p o i n t , b u t a v e r y d i f f i c u l t a p p l i c a t i o n f r o m a p r a c t i c a l v i e w p o i n t ( L i p i n s k y e t al., 1985). A v e r y e x c i t i n g a r e a o f a p p l i c a t i o n f o r f a t t y a c i d s a n d t h e i r d e r i v a t i v e s i s t h e c o s m e t i c a n d d r u g o r p h a r m a c e u t i c a l i n d u s t r i e s . P a l m i t i c , s t e a r i c , m y r i s t i c a n d s h o r t c h a i n f a t t y a c i d s a r e o f a p a r t i c u l a r i n t e r e s t i n t h i s r e s p e c t . A l i s t o f a p p l i c a t i o n s i s a s f o l l o w s : s h a v i n g c r e a m s , b a t h o i l s , a e r o s o l h a i r c o n d i t i o n e r s , f l u i d h a i r c o n d i t i o n e r s , h a n d c r e a m s , a n t i p e r s p i r a n t s , e y e make-up, n a i l w h i t e n e r s , shampoos, a n d f a c e p o w d e r s ( K a l u s t i a n , 1985). 3 . METHODOLOGY 3.1. Sample Collection and Preparation Wood s a m p l e s w ere o b t a i n e d f r o m t h r e e l i v i n g t r e e s o f s l a s h p i n e (Pinus e l l i o t t i i Engelm.) f r o m F l o r i d a . L o g s 25 cm l o n g t a k e n a t 1.5 m h e i g h t a b o v e t h e g r o u n d w e r e d e b a r k e d m a n u a l l y a n d sawn i n t o 1.5 cm d i s k s . The d i s k s w e r e a i r d r i e d f o r v a r i o u s p e r i o d s (24 t o 52 weeks) i n a CTH room a t 23°C, 65%RH a n d c h i p p e d b y h a n d a s r e q u i r e d . C h i p s a m p l e s w ere g r o u n d i n a W i l e y m i l l t o p a s s 40 mesh (425 |lm) a n d t o be r e t a i n e d on a 60 mesh (250 |lm) s c r e e n . The wood m e a l was a l l o w e d t o a i r d r y i n t h e CTH room a t 23+ 2°C a n d 65± 2% r e l a t i v e h u m i d i t y . 3.2. Chemical Analysis of Wood A i r d r i e d wood m e a l s a m p l e s w e r e t a k e n f o r d e t e r m i n i n g t h e e x t r a c t i v e c o n t e n t , a c i d - i n s o l u b l e l i g n i n ( K l a s o n l i g n i n ) a n d a c i d - s o l u b l e l i g n i n (UV l i g n i n ) a c c o r d i n g t o TAPP I s t a n d a r d s T 204 o s - 7 6 , T 222 o s - 7 6 a n d TAPPI UM-250, r e s p e c t i v e l y . 50 3.2.1. Wood extractives determination To d e t e r m i n e t h e e f f e c t o f h e a t u p o n t h e d e g r a d a t i o n o f e x t r a c t i v e s , c o l d m e t h a n o l m a c e r a t i o n e x t r a c t i o n was c o m p a r e d w i t h a s t a n d a r d S o x h l e t e x t r a c t i o n u s i n g m e t h a n o l a s t h e s o l v e n t . F u r t h e r m o r e , b o t h t h e m a c e r a t i o n a n d t h e S o x h l e t e x t r a c t i o n r e s u l t s w e r e c o m p a r e d a g a i n s t t h e e x t r a c t i o n m e t h o d recommended b y TAP P I s t a n d a r d T 204 o s -76. 3.2.1.1. Cold methanol maceration 50 g o f wood m e a l was p l a c e d i n a 1 L E r l e n m e y e r f l a s k w i t h a d r a i n h o l e a t t h e b o t t o m a n d c o v e r e d w i t h 300 ml o f a n h y d r o u s m e t h a n o l c o n t a i n i n g known amount o f m e t h y l h e p t a d e c a n o a t e a s an i n t e r n a l s t a n d a r d ( c o n c e n t r a t i o n ~ 30 ng/fiL) . The m i x t u r e was a l l o w e d t o s t e e p f o r 54 h a t room t e m p e r a t u r e . The s o l v e n t was d e c a n t e d a n d f i l t e r e d on a m i l l i p o r e f i l t e r s y s t e m . The f i l t r a t e was c o n c e n t r a t e d t o a b o u t 5 mL u n d e r r e d u c e d p r e s s u r e i n a r o t a r y e v a p o r a t o r a t 40°C, t r a n s f e r r e d q u a n t i t a t i v e l y t o a t a r e d e v a p o r a t i o n d i s h a n d e v a p o r a t e d t o d r y n e s s i n a fume h o o d . F i n a l l y , t h e d i s h was p l a c e d i n a f r e e z e - d r i e r f o r 48 h a n d f i n a l l y w e i g h e d . 51 3.2.1.2. Methanol Soxhlet extraction Wood m e a l s a m p l e s w ere e x t r a c t e d i n a S o x h l e t a p p a r a t u s f o r 54 h w i t h a n h y d r o u s m e t h a n o l c o n t a i n i n g known amounts o f m e t h y l h e p t a d e c a n o a t e a s a n i n t e r n a l s t a n d a r d ( c o n c e n t r a t i o n ~30ng/|xL) . F o r s a m p l e s w e i g h i n g a p p r o x i m a t e l y 40 g, a b o u t 300 mL o f a n h y d r o u s m e t h a n o l a n d some b o i l i n g s t o n e s w ere u s e d . E x t r a c t i o n was p e r f o r m e d a t a s i p h o n i n g r a t e o f 4 c y c l e s p e r h o u r . The e x t r a c t was e v a p o r a t e d u n d e r r e d u c e d p r e s s u r e i n a r o t a r y e v a p o r a t o r a t 40°C, t r a n s f e r r e d q u a n t i t a t i v e l y t o a t a r e d e v a p o r a t i o n d i s h a n d e v a p o r a t e d i n a fume h o o d t o d r y n e s s . S u b s e q u e n t l y , t h e s a m p l e s w ere d r i e d i n a f r e e z e d r i e r f o r 48 h a n d f i n a l l y q u a n t i f i e d . 3.2.1.3. Ethanol-benzene Soxhlet extraction E t h a n o l - b e n z e n e e x t r a c t i o n was c a r r i e d o u t a c c o r d i n g t o T A P P I s t a n d a r d T 204 o s - 7 6 . 3.2.2. Acid-insoluble l i g n i n A i r - d r i e d , e x t r a c t i v e - f r e e wood m e a l was u s e d f o r d e t e r m i n a t i o n o f t h e a c i d - i n s o l u b l e l i g n i n ( K l a s o n l i g n i n ) c o n t e n t a c c o r d i n g t o a m o d i f i e d T A P P I s t a n d a r d T 222 o s - 7 6 52 m e t h o d . A m o d i f i c a t i o n o f t h e s e c o n d a r y h y d r o l y s i s was u s e d i n t h i s p r o c e d u r e . A f t e r d i l u t i o n w i t h w a t e r t o 3% c o n c e n t r a t i o n o f s u l f u r i c a c i d , t h e s o l u t i o n was t r e a t e d i n an a u t o c l a v e u n d e r s t e a m p r e s s u r e o f 1.5 b a r (20 p s i ) a n d a t 127.5°C f o r 1 h. The i n s o l u b l e m a t e r i a l was a l l o w e d t o s e t t l e o v e r n i g h t . Then, t h e c l e a n s u p e r n a t a n t was c a r e f u l l y d e c a n t e d t h r o u g h a medium p o r o s i t y f i l t e r i n g c r u c i b l e . F i n a l l y , t h e l i g n i n was q u a n t i t a t i v e l y c o l l e c t e d b y vacuum f i l t r a t i o n o n t o t h e c r u c i b l e a n d o v e n - d r i e d a t 105± 3°C f o r 1 h. The a c i d f i l t r a t e was s a v e d f o r t h e a c i d - s o l u b l e l i g n i n (UV l i g n i n ) c o n t e n t d e t e r m i n a t i o n . 3.2.3. Acid-soluble l i g n i n Though l i g n i n i s i n s o l u b l e i n s t r o n g a c i d s , s m a l l a mounts a r e d i s s o l v e d d u r i n g K l a s o n l i g n i n d e t e r m i n a t i o n . T h i s a c i d - s o l u b l e l i g n i n (UV l i g n i n ) was d e t e r m i n e d a c c o r d i n g t o TAPPI UM 250 i n c o m b i n a t i o n w i t h T 222 os-74 ( K l a s o n l i g n i n ) . UV a b s o r p t i o n m e a s u r e m e n t s o f t h e a c i d f i l t r a t e w e r e p e r f o r m e d a t 2 05 nm w a v e l e n g t h on a S h i m a d z u U V - V i s i b l e r e c o r d i n g s p e c t r o p h o t o m e t e r ( U V - 1 6 0 ) . The a c i d s o l u b l e l i g n i n c o n t e n t was c a l c u l a t e d by u s i n g t h e f o l l o w i n g e q u a t i o n : 53 L i g n i n (%) = B x V x 100 1000 x W w h e r e : B = l i g n i n c o n t e n t (g/1000 mL), V = t o t a l v o l u m e o f s o l u t i o n , W = o v e n - d r y w e i g h t o f wood m e a l B c a n be c a l c u l a t e d f r o m : B = A x D 110 . where : A = UV a b s o r b a n c e a t 205 nm D = d i l u t i o n f a c t o r 110 = a b s o r p t i v i t y , e 3.3. Preliminary Studies f o r the Characterization of  Resin- and Fatty Acids 3.3.1. Gas chromatographic studies Gas c h r o m a t o g r a p h y was c a r r i e d o u t w i t h a H e w l e t t -P a c k a r d 5890A g a s c h r o m a t o g r a p h e q u i p p e d w i t h a f l a m e i o n i z a t i o n d e t e c t o r a n d a HP 3396A i n t e g r a t o r . The r e p o r t s g e n e r a t e d on t h e HP 3396A p r i n t e r , a f t e r e a c h c h r o m a t o g r a p h i c r u n , were t r a n s f e r r e d t o a c o m p u t e r f o r d a t a s t o r a g e . A f t e r s e v e r a l t r i a l s u s i n g d i f f e r e n t s t a t i o n a r y p h a s e s , HP - 5 was c h o s e n as t h e s t a t i o n a r y p h a s e due t o i t s b e s t r e s o l u t i o n f o r t h e r e s i n a c i d s a n d DB - 2 2 5 f o r i t s b e s t r e s o l u t i o n o f t h e f a t t y a c i d s . F o r i d e n t i f i c a t i o n a n d 54 q u a n t i f i c a t i o n o f r e s i n - a n d f a t t y a c i d s t h e s e two c a p i l l a r y c o l u m n s were u s e d . R e s i n a c i d s were a n a l y s e d on a HP-5 f u s e d - s i l i c a c r o s s - l i n k e d b o n d e d p h a s e c a p i l l a r y c o l u m n (25 m, 0.2 mm, 0.33 (lm) . The t e m p e r a t u r e p r o g r a m was s e t f o r 5 m i n a t 40°C, f o r 30 m i n a t 15°C/min t o 215°C a n d f o r 30 m i n i n c r e a s e a t 3°C/min t o 250°C. The t e m p e r a t u r e o f t h e i n j e c t o r was s e t a t 200°C a n d t h a t o f t h e d e t e c t o r a t 300°C. The i n j e c t i o n v o l u m e was 1.4 |1L i n t h e s p l i t l e s s mode. H e l i u m was u s e d as t h e c a r r i e r g a s a t a f l o w r a t e o f 1.7 mL/min. F a t t y a c i d s were r e s o l v e d on a DB-225 J&W f u s e d -s i l i c a m e g a bore c o l u m n (15 m, 0.537 mm, 1.0 Jim). The r u n s w e r e p e r f o r m e d i s o t h e r m a l l y a t 170°C. The t e m p e r a t u r e s o f t h e i n j e c t o r a n d d e t e c t o r w e re 200°C a n d 300°C, r e s p e c t i v e l y . The i n j e c t i o n v o l u m e was 1.4 (IL i n t h e s p l i t l e s s mode. H e l i u m was u s e d as t h e c a r r i e r g a s a t a f l o w r a t e o f 5.0 mL/min. 3.3.1.1. Methylation of r e s i n - and f a t t y acids M e t h y l a t i o n o f b o t h r e s i n - a n d f a t t y a c i d s were c a r r i e d o u t w i t h f r e s h d i a z o m e t h a n e ( C H 2 N 2 ) p r e p a r e d a c c o r d i n g t o de B o e r a n d B a c k e r ( 1 9 6 3 ) . The d i a z o m e t h a n e g e n e r a t i n g s y s t e m was c o n s t r u c t e d a c c o r d i n g t o de B o e r 55 a n d B a c k e r (1963) f r o m common c o m p o n e n t s a v a i l a b l e i n t h e l a b o r a t o r y w h i c h c a n be e a s i l y d i s m a n t l e d f o r s t o r a g e . The g e n e r a t o r s y s t e m was c l a m p e d i n a fume h o o d b e h i n d a n e x p l o s i o n p r o o f s h i e l d . The e s t e r i f i c a t i o n a p p a r a t u s i s a m o d i f i c a t i o n o f t h e one p r o p o s e d b y L e v i t t (1973) a n d c o n s i s t s b a s i c a l l y o f a d i a z o m e t h a n e g e n e r a t o r , s o u r c e o f i n e r t g a s a n d t h e e s t e r i f i c a t i o n r e c e p t a c l e ( F i g . 10). The g e n e r a t o r i s a 360 mm l o n g x 20 mm d i a m e t e r t e s t t u b e e q u i p p e d w i t h a g r o u n d j o i n t w h i c h i s j o i n e d t o a g l a s s b u l b h a v i n g t h r e e s i d e a r ms. One o f t h e s e s i d e arms i s u s e d t o c o n n e c t t h e b u l b t o a n i t r o g e n g a s s o u r c e , a n o t h e r one h o l d s a s m a l l d r o p p i n g t u b e w i t h a s t o p c o c k a n d t h e t h i r d s i d e arm c o n n e c t s t o t h e e s t e r i f i c a t i o n r e c e p t a c l e . I n t h e t e s t t u b e 10 mL o f e a c h o f d i e t h y l e t h e r a n d 2 - e t h o x y e t h a n o l a n d t h e a p p r o p r i a t e amount o f N-m e t h y l - N - n i t r o s o - p - t o l u e n e s u l f o n a m i d e * a r e p l a c e d . The t e s t t u b e i s t h e n c o n n e c t e d t o t h e b u l b . I n e r t g a s ( i . e . n i t r o g e n ) i s p a s s e d t h r o u g h t h e s y s t e m f o r a p p r o x i m a t e l y 30 s e c o n d s , w h i l e a t t h e same t i m e 2 mL o f 60% a q u e o u s p o t a s s i u m h y d r o x i d e i s a d d e d t o t h e d r o p p i n g t u b e . The g a s f l o w i s t h e n i n t e r r u p t e d a n d t h e s t o p c o c k i s o p e n e d t o a l l o w t h e KOH t o d r a i n i n t o t h e g e n e r a t o r . The t e s t t u b e i s h e a t e d i n a w a t e r b a t h t o 70°C. A f t e r c l o s i n g t h e s t o p c o c k t h e g a s f l o w i s r e s u m e d a t a r a t e o f 1-2 *. The amounts o f d i a z o m e t h a n e g e n e r a t o r u s e d f o r i n d i v i d u a l a n d m i x e d s a m p l e s w ere 0.6 a n d 2.5 g , r e s p e c t i v e l y . 56 Figure 10. Apparatus used for methylation of the resin and fatty acids 57 b u b b l e s p e r s e c o n d . A t t h i s p o i n t , t h e e t h e r e a l d i a z o m e t h a n e g e n e r a t e d i s sw e p t o u t o f t h e g e n e r a t o r b y t h e n i t r o g e n g a s a n d i s i n t r o d u c e d i n t o t h e s a m p l e b y means o f a P a s t e u r p i p e t d u r i n g a f i x e d t i m e ( S e c t i o n 3 . 3 . 1 . 1 . 1 ) . The s a m p l e i s d i s s o l v e d i n an a p p r o p r i a t e s o l v e n t ( S e c t i o n 3.3.1.1.2) The s a m p l e i s t h e n s e t a s i d e f o r 1 t o 2 m i n t o a l l o w t h e e s t e r i f i c a t i o n t o be c o m p l e t e d . F i n a l l y , t h e e s t e r i f i e d s o l u t i o n i s p u r g e d w i t h n i t r o g e n g a s i n o r d e r t o sweep o u t t h e e x c e s s d i a z o m e t h a n e . A t t h i s p o i n t t h e s a m p l e i s r e a d y f o r GC a n d GC-MS a n a l y s i s . A f t e r t h e e s t e r i f i c a t i o n i s f i n i s h e d , t h e e x c e s s e t h e r e a l d i a z o m e t h a n e i n t h e g e n e r a t o r i s v e n t e d i n t o t h e fume h o o d a n d 10% a c e t i c a c i d i s a d d e d d r o p w i s e t o d e s t r o y a n y t r a c e s o f u n r e a c t e d n i t r o s o a m i d e a n d / o r d i a z o m e t h a n e a n d t o n e u t r a l i z e t h e b a s e . 3.3.1.1.1. Time of methylation reaction The e x t r a c t i v e s h a d t o be d e r i v a t i z e d t o i n c r e a s e t h e i r v o l a t i l i t y f o r GC a n a l y s i s . M e t h y l e s t e r d e r i v a t i v e s o f r e s i n - a n d f a t t y a c i d s a r e t h e most common d e r i v a t i v e s f o r g a s c h r o m a t o g r a p h i c a n a l y s i s ( F o u r i e a n d B a s s o n , 1990) . M o s t o f t h e p u b l i s h e d t e c h n i q u e s f o r m e t h y l a t i o n s u g g e s t t h e d r o p w i s e a d d i t i o n o f f r e s h l y p r e p a r e d e t h e r e a l 58 s o l u t i o n o f d i a z o m e t h a n e i n t o t h e s a m p l e u n t i l i t j u s t a t t a i n s a f a i n t y e l l o w c o l o r ( L e v i t t , 1 9 7 3 ; Z i n k e l a n d Han, 198 6) . The amount o f d i a z o m e t h a n e d e l i v e r e d t o t h e s a m p l e d u r i n g m e t h y l a t i o n d e p e n d s on f a c t o r s s u c h a s : t h e f l o w o f t h e n i t r o g e n g a s ( c a r r i e r o f t h e d i a z o m e t h a n e p r o d u c e d ) , t h e l e n g t h o f t i m e o f e x p o s u r e t o t h e g a s s t r e a m ( b u b b l i n g ) , t h e t e m p e r a t u r e o f t h e w a t e r b a t h o f t h e g e n e r a t o r , a n d t h e amount o f n i t r o s o a m i d e a d d e d . G e n e r a l l y , 1.5 t o 2 m i n a r e n e e d e d f o r t h e p a l e y e l l o w c o l o r t o show up i n t h e s a m p l e s o l u t i o n t o i n d i c a t e an e x c e s s o f d i a z o m e t h a n e . A c c o r d i n g t o Z i n k e l a n d Han (1986) m e t h y l a t i o n o f d e h y d r o a b i e t i c a c i d i n e t h e r / m e t h a n o l (9:1) was f u l l y c o m p l e t e d a f t e r 1 m i n (See T a b l e 9 ) . Table 9. Rates of methylation of dehydroabietic a c i d with diazomethane i n various solvents.(Zinkel and Han, 1986) Solvents 5 min R e a c t i o n T i m e * 3 min 1 min B e n z e n e T o l u e n e E t h e r E t h e r / M e O H (9:1) 97 % 95 % 95 % 100 % 91 % 96 % 34 % 100 % 11 100 "5 * A d d 5 t o 15 s e c f o r e v a p o r a t i o n o f d i a z o m e t h a n e . 59 When w o r k i n g w i t h c o l o r l e s s m o d e l s t a n d a r d s , i t i s e a s y t o m o n i t o r t h e m e t h y l a t i o n r e a c t i o n s i n c e an e x c e s s o f d i a z o m e t h a n e i s d e t e c t e d b y t h e y e l l o w i n g o f t h e s o l u t i o n . However, i n t h e c a s e o f c o l o r e d s o l u t i o n s ( i . e . wood e x t r a c t s ) t h e a p p e a r a n c e o f t h e y e l l o w c o l o r i s c a m o u f l a g e d b y t h e c o l o r i n g m a t e r i a l s i n s o l u t i o n . F o r t h i s r e a s o n , i t was n e c e s s a r y t o d e v i s e an a l t e r n a t e means o f s e n s i n g t h e c o m p l e t i o n o f t h e m e t h y l a t i o n r e a c t i o n . As an a l t e r n a t i v e , m e t h y l a t i o n o f c o l o r e d s o l u t i o n s ( i . e . wood e x t r a c t s ) was p e r f o r m e d a t f i x e d t i m e s . Thus a s e r i e s o f e x p e r i m e n t s w e re p e r f o r m e d i n o r d e r t o d e t e r m i n e t h e optimum t i m e f o r c o m p l e t e m e t h y l a t i o n o f t h e r e s i n - a n d f a t t y a c i d s . Known amounts o f d e h y d r o a b i e t i c a c i d a n d m e t h y l h e p t a d e c a n o a t e ( i n t e r n a l s t a n d a r d ) w e re d i s s o l v e d i n d i c h l o r o m e t h a n e - m e t h a n o l (9:1) a n d r e f l u x e d w i t h f r e s h l y p r e p a r e d d i a z o m e t h a n e f o r 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5 a n d 5 m i n p e r i o d s . A f t e r t h e i n d i c a t e d t i m e , t h e r e a c t i o n was s t o p p e d b y e v a p o r a t i n g t h e e x c e s s o f d i a z o m e t h a n e u n d e r a s t r e a m o f n i t r o g e n g a s . The s a m p l e s w ere t r a n s f e r r e d t o a 25 mL v o l u m e t r i c f l a s k a n d t h e f i n a l v o l u m e made up w i t h d i c h l o r o m e t h a n e a n d t h e n a n a l y z e d b y g a s c h r o m a t o g r a p h y ( GC). 60 3.3.1.1.2. Solvent se l e c t i o n f o r methylation I n t h i s e x p e r i m e n t , p a l m i t i c , d e h y d r o a b i e t i c a n d a b i e t i c a c i d s w e re m e t h y l a t e d i n t h r e e d i f f e r e n t s o l v e n t s : e t h e r - m e t h a n o l ( 9 : 1 ) , d i c h l o r o m e t h a n e - m e t h a n o l (9:1) a n d m e t h a n o l . Known amounts o f m e t h y l h e p t a d e c a n o a t e were a d d e d t o t h e s e s o l u t i o n s a s i n t e r n a l s t a n d a r d s . D u r i n g t h e s e e x p e r i m e n t s t h e o n l y v a r i a b l e was t h e r e a c t i o n t i m e , w h i l e a l l o t h e r p a r a m e t e r s f o r m e t h y l a t i o n r e m a i n e d c o n s t a n t . 3.3.2. Saponification of e s t e r i f i e d f a t t y acids S a p o n i f i c a t i o n was c a r r i e d o u t a c c o r d i n g t o Ekman (197 9) a n d t h e p r o d u c t s a n a l y s e d b y GC a n d GC-MS. F r a c t i o n s t o be s a p o n i f i e d w e re e v a p o r a t e d t o d r y n e s s p r i o r t o t h e a d d i t i o n o f a 0. 4N KOH s o l u t i o n i n 90% e t h a n o l . T h i s m i x t u r e was a l l o w e d t o s t a n d f o r 4 h a t 7 0 2 C t o a l l o w s a p o n i f i c a t i o n o f t h e e s t e r s . A t t h e e n d o f t h e r e a c t i o n , t h e m i x t u r e was d i l u t e d w i t h w a t e r (1:1 v / v ) a n d a c i d i f i e d w i t h 0. 4N H 2 S 0 4 . The a c i d c o n s t i t u e n t s w e re i s o l a t e d b y s u c c e s s i v e e x t r a c t i o n s w i t h d i e t h y l e t h e r . The c o m b i n e d e x t r a c t s were e v a p o r a t e d a n d r e d i s s o l v e d w i t h a d i c h l o r o m e t h a n e - m e t h a n o l (9:1) m i x t u r e p r i o r t o m e t h y l a t i o n . The r e s u l t i n g r e s i n - a n d f a t t y a c i d s were a n a l y s e d b y GC a s d e s c r i b e d a b o v e . 61 3 . 4 . Characterization of Resin- and Fatty Acids from Wood C h a r a c t e r i z a t i o n o f r e s i n - a n d f a t t y a c i d s w e re p e r f o r m e d i n a s i m i l a r way f o r t h e c o l d m e t h a n o l m a c e r a t i o n , m e t h a n o l S o x h l e t , a n d e t h a n o l - b e n z e n e S o x h l e t e x t r a c t i o n s . C r u d e e x t r a c t s w e r e t a k e n a f t e r f r e e z e - d r y i n g a n d d i v i d e d i n t o two p o r t i o n s . The f i r s t p a r t was m e t h y l a t e d d i r e c t l y f o r t h e a n a l y s i s o f r e s i n a c i d s a n d f r e e f a t t y a c i d s , a n d t h e s e c o n d s a m p l e was s a p o n i f i e d and l a t e r m e t h y l a t e d i n o r d e r t o a c c o u n t f o r t h e t o t a l f a t t y a c i d c o n t e n t o f t h e wood. The a n a l y t i c a l p r o c e d u r e f o r t h e d e t e r m i n a t i o n o f r e s i n - a n d f a t t y a c i d s p r e s e n t i n wood c o n s i s t e d o f t h r e e m a j o r s t e p s : 1) r e m o v a l , c o n c e n t r a t i o n a n d q u a n t i f i c a t i o n o f t h e t o t a l e x t r a c t i v e s , 2) s a p o n i f i c a t i o n a n d / o r m e t h y l a t i o n o f r e s i n - a n d f a t t y a c i d s , a n d 3) i d e n t i f i c a t i o n a n d q u a n t i f i c a t i o n o f i n d i v i d u a l r e s i n - a n d f a t t y a c i d s b y GC a n d GC-MS. An a b b r e v i a t e d s e q u e n c e i s shown i n F i g . 1 1 . 3.4.1. Gas chromatographic analysis A n a l y s i s o f r e s i n a c i d s was p e r f o r m e d on a HP-5 f u s e d - s i l i c a c r o s s - l i n k e d b o n d e d p h a s e c a p i l l a r y c o l u m n (25 m, 0.2 mm, 0.33 p:m) a n d t h a t o f t h e f a t t y a c i d s on a DB-225 f u s e d - s i l i c a m egabore c o l u m n (15m, 0.537mm, 1. Ofim) . Wood Wood Meal Extract 1 .Me thy la t ion 2 . G C / G C - M S Resin Acids + Free Fatty Acids Maceration Soxhlet C H 3 O H C H 3 O H 54 h. 54 h. 1.Rotary E v a p o r a t o r ' 2 .Freeze—Dry ing W E = T o t a l E x t r a c t i v e s Extract 1 . S a p o n i f i c a t i o n 2. Me thy la t i on 3. G C / G C — M S Resin Acids + Total Fatty Acids 1 .Methy la t ion 2 .GC/GC—MS Resin Acids + Free Fatty Acids 1 . S a p o n i f i c a t i o 2. M e t h y l a t i o n 3. G C / G C — M S Resin Acids + Total Fatty Acids Figure 11. Flow diagram f o r the removal, i d e n t i f i c a t i o n and q u a n t i f i c a t i o n of the resin and f a t t y acids present i n slash pine wood. Acids were determined as t h e i r methyl ester derivatives 63 C o n d i t i o n s f o r b o t h d e t e r m i n a t i o n s w e re g i v e n e a r l i e r (See s e c t i o n 3 . 3 . 1 ) . 3.4.2. Preparation of c a l i b r a t i o n curve R e s i n a c i d s were o b t a i n e d f r o m H e l i x B i o t e c h S c i e n t i f i c L t d . a n d t h e f a t t y a c i d s w e re s e c u r e d f r o m A l d r i c h C h e m i c a l s Company, I n c . L i n o l e i c a n d l i n o l e n i c a c i d s w e r e o b t a i n e d as f r e e a c i d s w h i l e p a l m i t i c , s t e a r i c a n d o l e i c a c i d s were b o u g h t as t h e i r m e t h y l e s t e r d e r i v a t i v e s . M e t h y l a t i o n o f t h e d i f f e r e n t a c i d s was c a r r i e d o u t by r e f l u x i n g them w i t h a f r e s h l y p r e p a r e d d i a z o m e t h a n e s o l u t i o n d u r i n g a 4 m i n r e a c t i o n t i m e . A l l s a m p l e s w ere d i s s o l v e d i n d i c h l o r o m e t h a n e - m e t h a n o l (9:1) p r i o r t o m e t h y l a t i o n . C a l i b r a t i o n c u r v e s were p r e p a r e d by u s i n g s t a n d a r d s o l u t i o n s o f r e s i n - a n d f a t t y a c i d m e t h y l e s t e r s a t t h r e e d i f f e r e n t c o n c e n t r a t i o n l e v e l s , a l l c o n t a i n i n g t h e same amount o f m e t h y l h e p t a d e c a n o a t e as i n t e r n a l s t a n d a r d . R e s p o n s e f a c t o r s f o r a l l r e s i n - a n d f a t t y a c i d s were c a l c u l a t e d b y t h e i n t e g r a t o r . 64 3.4.3. Gas chomatography-mass spectrometry (GC-MS) The mass s p e c t r a w e re r e c o r d e d w i t h a F i n n i g a n 1020 mass s p e c t r o m e t e r c o u p l e d t o a P e r k i n E l m e r 3B g a s c h r o m a t o g r a p h . The t e m p e r a t u r e p r o g r a m was s i m i l a r t o t h a t u s e d i n GC. The t e m p e r a t u r e o f t h e i n j e c t i o n p o r t was s e t a t 250°C, a n d t h e i o n s o u r c e was k e p t a t 95°C. S p l i t i n j e c t i o n mode a t a (100:1) r a t i o was u s e d w i t h an i n j e c t i o n v o l u m e o f 1.0 u,L. The i o n i z a t i o n v o l t a g e was 70eV a n d t h e r e s o l u t i o n was s e t a t 1000. The s c a n n i n g mass r a n g e was 40 t o 450 i n 1 s e c . 3.5. Organosolv pulping of slash pine M a n u a l l y d e b a r k e d d i s k s o f s l a s h p i n e wood were s t o r e d f o r 24 weeks i n t h e c o n t r o l l e d t e m p e r a t u r e a n d h u m i d i t y (CTH) room a t 23± 2°C a n d 65± 2% r e l a t i v e h u m i d i t y . C h i p s w e r e p r e p a r e d b y h a n d c u t t i n g on a g u i l l o t i n e t o a s t a n d a r i z e d c h i p s i z e : 2.5 cm x 1.5 cm x 0.3-0.5 cm. C h i p m o i s t u r e c o n t e n t was d e t e r m i n e d b e f o r e c o o k i n g . 65 3.5.1. Pulping conditions S e r i e s o f p u l p s w e re p r e p a r e d f r o m s l a s h p i n e c h i p s b y t r e a t m e n t w i t h a p u l p i n g l i q u o r a n d t h e c o n d i t i o n s (Chang a n d P a s z n e r , 1 9 82; P a s z n e r a n d , Chang 1983) g i v e n b e l o w : Wood s l a s h p i n e C h a r g e o f A.D. c h i p s , g ....13 - 14 P u l p i n g l i q u o r M e t h a n o l - H 2 0 , % 80 : 20 L i q u o r - t o - w o o d r a t i o ..10 : 1 C a t a l y s t s C a C l 2 , M 0.025 M g ( N 0 3 ) 2 , M 0.025 C o o k i n g t e m p e r a t u r e , °C ....205 C o o k i n g t i m e , m i n 5, 20, 40 a n d 60 P r e s s u r e , b a r a) H i g h p r e s s u r e (197) b) N o r m a l p r e s s u r e * (40) * N o r m a l p r e s s u r e p u l p i n g i s a c c o m p l i s h e d w i t h o u t p r e s s u r i z i n g t h e v e s s e l s p r i o r t o i m m e r s i o n i n t o t h e b o i l i n g b a t h . 66 3.5.2. High pressure organosolv pulping F o u r d i f f e r e n t p u l p i n g t i m e s w e r e s e t t o d e t e r m i n e t h e r a t e o f e x t r a c t i v e s r e m o v a l t o g e t h e r w i t h t h a t o f r e s i d u a l l i g n i n a n d a l s o t o d e t e r m i n e t h e p u l p y i e l d . C o o k s were made i n a 175 mL v e s s e l w h i c h was p u r g e d w i t h a r g o n a t e l e v a t e d p r e s s u r e p r i o r t o i t s i m m e r s i o n i n t o a p r e h e a t e d g l y c e r o l b a t h w h i c h was m a i n t a i n e d a t 205°C. A t e a c h c o o k i n g t i m e t h r e e o r f o u r c o o k s w e r e p e r f o r m e d i n o r d e r t o g e t s t a t i s t i c a l l y r e p r e s e n t a t i v e r e s u l t s . A f t e r e a c h c o o k i n g t r i a l , t h e v e s s e l was q u e n c h e d i n a c o l d w a t e r b a t h u n t i l t h e i n s i d e p r e s s u r e was l o w e n o u g h t o o pen i t . The p u l p i n g l i q u o r was c a r e f u l l y d e c a n t e d a n d t h e c o o k e d c h i p s r e m o v e d f r o m t h e v e s s e l , w a s h e d w i t h f r e s h c o o k i n g l i q u o r a n d r i n s e d w i t h m e t h a n o l . A l l t h e s o l v e n t f r a c t i o n s were c o l l e c t e d as t h e " i n i t i a l black l i q u o r " . The c o o k e d c h i p s w e re d i s i n t e g r a t e d i n a 250 mL W a r i n g b l e n d e r w i t h f r e s h m e t h a n o l f o r one m i n u t e a n d t h e d i s i n t e g r a t e d f i b e r s w e r e c o l l e c t e d on a 15 cm B u c h n e r f u n n e l ( p r e - w e i g h e d f i l t e r p a p e r was u s e d ) a n d w a s h e d t w i c e w i t h m e t h a n o l (60 mL) , once, w i t h w a t e r (25 mL) a n d t h e n w i t h m e t h a n o l (30 mL). The f i l t r a t e , c o n t a i n i n g a d d i t i o n a l r e s i n - a n d f a t t y a c i d s a n d d i s s o l v e d l i g n i n f r o m t h e p u l p , was c o m b i n e d w i t h t h e " i n i t i a l black l i q u o r " t o g i v e t h e "mother black l i q u o r " . 67 L i g n i n s , w h i c h p r e c i p i t a t e d on c o o l i n g f r o m t h e i r r e s p e c t i v e m o t h e r b l a c k l i q u o r s ("Lignin I"), were s e t a s i d e f o r q u a n t i t a t i v e a n a l y s i s , a n d a l s o f o r i d e n t i f i c a t i o n a n d q u a n t i f i c a t i o n o f t h e r e s i n - a n d f a t t y a c i d s a d s o r b e d o n t o t h e i r s u r f a c e . (See s e c t i o n 3.5.2.2) R e m o v a l o f "Lignin I" f r o m t h e "mother black l i q u o r " l e f t t h e "black l i q u o r A" c o n t a i n i n g most o f t h e e x t r a c t i v e s a n d a s o l u b l e l i g n i n . The f i n a l v o l u m e o f t h e f i l t r a t e , c o n t a i n i n g t h e i n t e r n a l s t a n d a r d , was made up t o 250 mL i n a v o l u m e t r i c f l a s k a n d s a v e d f o r GC a n d GC-MS a n a l y s i s . An a n a l y t i c a l scheme i s o u t l i n e d i n F i g . 1 2 a . A l i q u o t s f r o m "black l i q u o r A" were t a k e n f o r r e s i n -a n d f a t t y a c i d c h a r a c t e r i z a t i o n (50 mL) a n d a l s o t a k e n f o r t h e q u a n t i t a t i v e a n a l y s i s o f t h e l i g n i n s o l u b i l i z e d i n t h e b l a c k l i q u o r . An a l i q u o t o f 150 mL o f "black l i q u o r A" was d i l u t e d i n 1500 mL o f w a t e r t o p r o v o k e p r e c i p i t a t i o n o f t h e s o l u b l e l i g n i n d e s i g n a t e d as "Lignin S"* . The p r e c i p i t a t e was a l l o w e d t o s e t t l e o v e r n i g h t , t h e n vacuum f i l t e r e d , t r a n s f e r r e d t o a t a r e d a l u m i n u m d i s h a n d f i n a l l y f r e e z e - d r i e d f o r 24 h. T h i s l i g n i n was q u a n t i f i e d a n d a l s o t a k e n f o r G e l P e r m e a t i o n C h r o m a t o g r a p h y (GPC) m o l e c u l a r w e i g h t a n a l y s i s on an HPLC ( S e c t i o n 3 . 6 . 1 ) . * " L i g n i n S" r e c o v e r e d b y d i r e c t p r e c i p i t a t i o n o f t h e c o o k i n g l i q u o r ( i . e . b e f o r e l i q u i d - l i q u i d e x t r a c t i o n o f t h e e x t r a c t i v e s ) i t w i l l be c o n t a m i n a t e d b y p r o p o r t i o n a l a mounts o f t h e c o p r e c i p i t a t i n g e x t r a c t i v e s r e m o v e d d u r i n g p u l p i n g . D e c a n t / W a s h i n g P u l p i n g B l a c k L i q u o r + L ign in + E x t r a c t i v e s F i b e r s E x t r a c t i v e s + C h i p s ( L i g n i n + E x t r a c t i v e s ) B l e n d i n g / W a s h i n g P u l p + E n t r a p p e d L i g n i n 4- E x t r a c t i v e s F i l t r a t i o n / W a s h i n g ^ L i g n i n — lij -< M o t h e r B l a c k L i q u o r + L i g n i n ( F i b e r s ) + E x t r a c t i v e s L i g n i n — I + F i b e r s + E x t r a c t i v e s D i s s o l u t i o n T H F / A c e t o n e / C H j O H L i g n i n + E x t r a c t i v e s F i l t r a t i o n L i g n i n — P P u l p + E x t r a c t i v e s S o x h l e t CH3OH E x t r a c t i v e s B l a c k L i q u o r " A " + E x t r a c t i v e s + D i s s o l v e d L i g n i n L i q - L i q E x t . ( E t 2 0 ) L i g n i n — S L i q - L i q E x t . ( E t 2 0 ) E x t r a c t i v e s L i g n i n R e s i d u a l B l a c k L i q u o r " F " Yie ld K a p p a N u m b e r co Figure 12a . Flow diagram f o r the recovery, i d e n t i f i c a t i o n and q u a n t i f i c a t i o n of the r e s i n and f a t t y acids i n the black l i q u o r and pulp a f t e r high ^pressure organosolv pulping of slash pine wood L i g n i n I I i s t o t a l r e c o v e r a b l e l i g n i n a f t e r p u l p i n g 69 The r e s u l t i n g p u l p s w e re a i r d r i e d i n t h e CTH room a n d s a m p l e s t a k e n f o r p u l p y i e l d ( u n s c r e e n e d ) , K a p p a number a n d r e s i d u a l r e s i n a n d f a t t y a c i d c o n t e n t d e t e r m i n a t i o n s . K a p p a numbers were o b t a i n e d a c c o r d i n g t o TA P P I s t a n d a r d T 236 o s - 7 6 . 3.5.2.1. Resin- and f a t t y a c i d removal and characterization from the black l i q u o r The a n a l y t i c a l p r o c e d u r e f o r d e t e r m i n i n g t h e r e s i n -a n d f a t t y a c i d s p r e s e n t i n t h e b l a c k l i q u o r , l i g n i n a n d p u l p c o n s i s t e d o f t h r e e m a j o r s t e p s : 1) i s o l a t i o n a n d c o n c e n t r a t i o n , 2) s a p o n i f i c a t i o - n a n d / o r m e t h y l a t i o n o f t h e r e s i n - a n d f a t t y a c i d s , a n d 3) i d e n t i f i c a t i o n a n d q u a n t i f i c a t i o n o f t h e r e s i n - a n d f a t t y a c i d s b y GC a n d / o r GC-MS. R e f e r e n c e t o t h e v a r i o u s s a m p l e s i s made as o u t l i n e d i n F i g . 1 2 a . " B l a c k l i q u o r A" c o l l e c t e d a f t e r r e m o v a l o f "Lignin I" was t r a n s f e r r e d t o a 250 mL v o l u m e t r i c f l a s k a n d 10 mL o f m e t h y l h e p t a d e c a n o a t e (-30 ng/u.L) was a d d e d a s an i n t e r n a l s t a n d a r d . The r e c o v e r y o f t h e r e s i n - a n d f a t t y a c i d s was c a r r i e d o u t by l i q u i d / l i q u i d e x t r a c t i o n w i t h d i e t h y l e t h e r u s i n g a 250 mL s e p a r a t o r y f u n n e l . S i n c e t h e p u l p i n g b l a c k l i q u o r ( m e t h a n o l - w a t e r p h a s e ) c o n t a i n e d b o t h t h e e x t r a c t i v e s a n d t h e s o l u b l e l i g n i n a 70 s o l v e n t was r e q u i r e d f o r t h e s e l e c t i v e r e m o v a l o f t h e r e s i n - a n d f a t t y a c i d s ( e x t r a c t i v e s i n g e n e r a l ) , l e a v i n g t h e l i g n i n a n d s u g a r s i n s o l u t i o n . I n a d d i t i o n t o t h i s c o n s i d e r a t i o n , i t was n e c e s s a r y t o l o o k f o r a s o l v e n t s y s t e m t h a t w o u l d e n a b l e t h e r e m o v a l o f t h e e x t r a c t i v e s w i t h o u t e m u l s i f i c a t i o n a n d p r e c i p i t a t i o n o f t h e d i s s o l v e d l i g n i n a n d t h u s t o a v o i d l o s e s o f t h e e x t r a c t i v e s by a d s o r p t i o n t o t h e p r e c i p i t a t e d l i g n i n o r any o t h e r a r t i f a c t . L i g n i n p r e c i p i t a t i o n f o l l o w s r e m o v a l ( r e c o v e r y ) o f t h e m e t h a n o l f r o m t h e b l a c k l i q u o r . T h e r e f o r e , i t was n e c e s s a r y n o t o n l y t o s e l e c t i v e l y remove t h e e x t r a c t i v e s f r o m t h e b l a c k l i q u o r , b u t a l s o t o d e t e r m i n e t h e p r o p e r p r o p o r t i o n s o f t h e s o l v e n t s a t w h i c h s e l e c t i v e p o l a r / n o n -p o l a r p h a s e s e p a r a t i o n t o o k p l a c e , w i t h o u t s o l v e n t e m u l s i f i c a t i o n a n d p r e c i p i t a t i o n o f t h e l i g n i n . The s o l v e n t a l s o h a d t o be a p o o r l i g n i n s o l v e n t . The e x t r a c t i v e s w e r e u s u a l l y c a r r i e d by t h e n o n - p o l a r s o l v e n t , w h i l e t h e l i g n i n r e m a i n e d s o l u b l e i n t h e p o l a r ( m e t h a n o l -w a t e r ) p h a s e . A f t e r t e s t i n g d i f f e r e n t s o l v e n t s ( i . e . p e t r o l e u m e t h e r , c h l o r o f o r m a n d d i e t h y l e t h e r ) , d i e t h y l e t h e r was c h o s e n a s t h e s o l v e n t f o r t h e e x t r a c t i o n due t o i t s g o o d d i s s o l v i n g p o w e r f o r t h e r e s i n - a n d f a t t y a c i d s . 71 3.5.2.1.1. Liquid-Liquid Extraction No s u i t a b l e p h a s e d i a g r a m was a v a i l a b l e f o r t h e t e r n a r y w a t e r - m e t h a n o l - e t h e r m i x t u r e , a n d t h u s f i r s t a p r o p e r p h a s e d i a g r a m h a d t o be p r e p a r e d . S e l e c t i v e l i q u i d p h a s e s e p a r a t i o n o f t h e t e r n a r y m i x t u r e ( m e t h a n o l - w a t e r -d i e t h y l e t h e r ) was d i f f i c u l t t o a t t a i n . A p h a s e d i a g r a m was c o n s t r u c t e d b a s e d on an e q u i l a t e r a l t r i a n g l e . I n t u r n , t h e c o r n e r s w e re a s s i g n e d 1 0 0 % c o n c e n t r a t i o n ( o r 0%) f o r e a c h o f t h e t h r e e s o l v e n t s . On e a c h s i d e o f t h e t r i a n g l e t h e p e r c e n t r a t i o s o f t h e p e r c e n t a g e s o f t h e two s o l v e n t s j o i n e d b y t h a t p a r t i c u l a r s i d e w e re p l o t t e d . D u r i n g i n i t i a l e x p e r i m e n t s , known p r o p o r t i o n s o f t h e w a t e r - m e t h a n o l m i x t u r e w e re p l a c e d i n 25 mL b e a k e r s a n d d i e t h y l e t h e r was a d d e d f r o m a 10 mL b u r e t (0.01 mL) u n t i l p h a s e s e p a r a t i o n was o b s e r v e d t o o c c u r . S i n c e a l l t h r e e s o l v e n t s w e re c o l o r l e s s , a c c u r a t e v i s u a l p e r c e p t i o n o f t h e p h a s e s e p a r a t i o n was v e r y d i f f i c u l t . I n o r d e r t o o v e r c o m e t h i s d i f f i c u l t y i t was n e c e s s a r y t o s e l e c t a d y e s u c h t h a t a t t h e p o i n t o f s e p a r a t i o n i t s h o u l d be p r e s e n t e i t h e r i n t h e e t h e r p h a s e o r i n t h e w a t e r - m e t h a n o l p h a s e . S e v e r a l d y e s w e r e t e s t e d . The b e s t d y e s f o r t h i s p u r p o s e p r o v e d t o be " F u c h s i n " a n d " A n i l i n e B l u e B l a c k " , t h e l a t t e r b e i n g s e l e c t e d a s t h e more a p p r o p r i a t e f o r t h e s e e x p e r i m e n t s . A s e r i e s o f d i f f e r e n t p r o p o r t i o n s o f t h e w a t e r -m e t h a n o l m i x t u r e w e re p l a c e d i n a 25 mL b e a k e r t o g e t h e r 72 w i t h t w o d r o p s o f a w a t e r s o l u t i o n o f a n i l i n e b l a c k b l u e a n d m i x e d t o g e t h e r b e f o r e t h e a d d i t i o n o f t h e d i e t h y l e t h e r . A f t e r a d d i t i o n o f known amounts o f e t h e r , t h e m i x t u r e was m i x e d w i t h a g l a s s r o d f o r 5 s e c a n d l e f t s t a n d i n g f o r a b o u t 5 t o 7 s e c t o s e e i f p h a s e s e p a r a t i o n t o o k p l a c e . F i v e t o s e v e n a t t e m p t s w e r e made f o r e a c h t r i a l b e f o r e f i n d i n g t h e m i n i m a l amount o f e t h e r n e e d e d f o r p h a s e s e p a r a t i o n w i t h a minimum o f i n t e r s o l u b i l i t y o f t h e s o l v e n t p h a s e s . By t a k i n g t h e o b t a i n e d v o l u m e s o f t h e d i e t h y l e t h e r a n d b y k n o w i n g t h e i n i t i a l v o l u m e s o f t h e w a t e r a n d m e t h a n o l s o l v e n t s , t h e t h r e e r a t i o s o f t h e c o m b i n a t i o n s o f w a t e r / m e t h a n o l , e t h e r / w a t e r a n d e t h e r / m e t h a n o l w e re p l o t t e d on t h e r e s p e c t i v e s i d e o f t h e t r i a n g l e . P e r p e n d i c u l a r l i n e s w e r e d r a w n f r o m t h e s e t h r e e p o i n t s a n d t h e i r i n t e r s e c t i o n p l o t t e d a s t h e p o i n t o f p h a s e s e p a r a t i o n f o r t h a t p a r t i c u l a r c o m b i n a t i o n . J o i n i n g a l l o f t h e s e p o i n t s g a v e a c u r v e w h i c h r e p r e s e n t e d a l l t h e p o i n t s a t w h i c h p h a s e s e p a r a t i o n t a k e s p l a c e . T h i s c u r v e c o u l d be u s e d t o p r e d i c t t h e p r o p e r p r o p o r t i o n s o f t h e s e t h r e e s o l v e n t s i f p h a s e s e p a r a t i o n w e re r e q u i r e d . P r e d i c t i o n s f o r p h a s e s e p a r a t i o n f r o m any p o i n t on t h i s c u r v e c a n be o b t a i n e d b y d r a w i n g p e r p e n d i c u l a r s t o e a c h s i d e o f t h e t r i a n g l e o r i g i n a t i n g f r o m t h a t p o i n t on t h e c u r v e . S i m i l a r a t t e m p t s w e re made w i t h d i f f e r e n t s t a r t i n g c o m b i n a t i o n s o f e t h e r / w a t e r a n d e t h e r / m e t h a n o l m i x t u r e s 73 and adding to these mixtures methanol and water, respectively, to reconstruct the phase separation curve. These tests provide confirmation and new points on the phase separation curve. Further, t h i s approach also allows l i q u i d / l i q u i d extraction to be approached from any water/methanol or ether/methanol r a t i o and provides further opportunity to p u r i f y the extractives by washing. 3.5.2.1.2. E f f i c i e n c y of the l i q u i d - l i q u i d extraction Recovery of the r e s i n - and f a t t y acids from the black liquor, by l i q u i d - l i q u i d extraction, were studied by taking water-methanol mixtures with r a t i o s i n the range of 1.0 (50:50) to 1.5 (60:40) with known concentrations of the r e s i n - and f a t t y acids. Aliquots of 50 mL of these solutions were placed i n a separatory funnel and extracted with d i e t h y l ether. The volume of d i e t h y l ether needed for phase separation for each p a r t i c u l a r r a t i o was determined and pl o t t e d i n F i g . 19 and 20. One minute shaking was followed by 3 min standing to allow phase separation. This extraction was followed by three additional extractions with 30 mL each of d i e t h y l ether. Then, the combined ethereal extracts were evaporated to almost dryness on a vacuum rotary evaporator under reduced pressure and l a t e r d r ied i n a freeze-drier for about 24 h before methylation. P r i o r to methylation the freeze-dried extracts were 74 r e d i s s o l v e d f i r s t w i t h m e t h a n o l a n d t h e n i n d i c h l o r o m e t h a n e s o t h a t t h e f i n a l s o l u t i o n was a m i x t u r e o f d i c h l o r o m e t h a n e - m e t h a n o l ( 9 : 1 ) . The m e t h y l a t e d s a m p l e s w e r e t r a n s f e r r e d t o a 25 mL v o l u m e t r i c f l a s k a n d t h e f i n a l v o l u m e made up w i t h d i c h l o r o m e t h a n e . T h e s e s a m p l e s were r e a d y f o r GC a n a l y s i s . 3.5.2.1.3. Quantification of the r e s i n and f a t t y acids i n the black l i q u o r When w o r k i n g w i t h t h e b l a c k l i q u o r , a n d i n o r d e r t o o b t a i n t h e r i g h t p r o p o r t i o n s , a l i q u o t s o f 50 mL o f b l a c k l i q u o r (~ m e t h a n o l - w a t e r , 80:20) were c o m b i n e d w i t h 40 mL o f w a t e r a n d 50 mL o f d i e t h y l e t h e r ( O m n i s o l v g r a d e ) i n a 250 mL s e p a r a t o r y f u n n e l . The f i n a l p r o p o r t i o n s o f m e t h a n o l - w a t e r - d i e t h y l e t h e r w e re a d j u s t e d t o 4 0 - 5 0 - 5 0 . F u n n e l e x t r a c t i o n , d r y i n g , m e t h y l a t i o n a n d GC a n a l y s i s w e r e p e r f o r m e d a s b e f o r e ( S e c t i o n 3 . 5 . 2 . 1 . 2 . ) . D u r i n g t h e s e e x t r a c t i o n s no e m u l s i o n s w e re f o r m e d a n d t h e r e f o r e l o s s e s o f t h e r e s i n a n d / o r f a t t y a c i d s w e r e v e r y u n l i k e l y t o h a p p e n . 75 3.5.2.2. Resin- and f a t t y acids removal from l i g n i n L i g n i n t h a t p r e c i p i t a t e d on c o o l i n g of the b l a c k l i q u o r ("Lignin I") , which was assumed to c o n t a i n some adsorbed e x t r a c t i v e s and some f i b e r fragments, was t r a n s f e r r e d t o a t a r e d medium p o r o s i t y c r u c i b l e . L i g n i n and e x t r a c t i v e s were d i s s o l v e d by u s i n g t e t r a h y d r o f u r a n (THF), acetone and methanol, s e q u e n t i a l l y and the remaining f i b e r s were oven d r i e d at 105+ 2°C f o r mass balance c a l c u l a t i o n ( y i e l d c o r r e c t i o n ) . The org a n i c l i g n i n - and e x t r a c t i v e s s o l u t i o n (THF, acetone, methanol) were evaporated and the r e s i d u e r e d i s s o l v e d i n methanol-water (80:20), t r a n s f e r r e d t o a 250 mL v o l u m e t r i c f l a s k c o n t a i n i n g a known amount of i n t e r n a l standard (-30 ng/|j.L) . An a l i q u o t (50 mL) of t h i s s o l u t i o n was taken f o r r e s i n - and f a t t y a c i d i d e n t i f i c a t i o n and q u a n t i f i c a t i o n as d e s c r i b e d b e f o r e (See S e c t i o n 3.5.2.1.3). A 150 mL p o r t i o n of t h i s l i g n i n s o l u t i o n was d i l u t e d i n 1500 mL of water i n order t o p r e c i p i t a t e the l i g n i n and q u a n t i f i e d i t i n a s i m i l a r manner as f o r " L i g n i n S" (See S e c t i o n 3.5.2). 3.5.2.3. Resin- and f a t t y acids removal from pulp R e s i n - and f a t t y a c i d s l e f t i n the pulp were e x t r a c t e d by a i r - d r y i n g the pulp f i r s t , ' f o l l o w e d by 76 S o x h l e t e x t r a c t i o n f o r 54 h u s i n g a n h y d r o u s m e t h a n o l ( O m n i s o l v g r a d e ) . On r e m o v a l o f t h e r e s i n - a n d f a t t y a c i d s f r o m t h e p u l p , some l i g n i n was c o - r e m o v e d t o g e t h e r w i t h t h e e x t r a c t i v e s , w h i c h was d e s i g n a t e d "Lignin P". The t o t a l e x t r a c t , c o n t a i n i n g e x t r a c t i v e s p l u s "Lignin P", was r e d i s s o l v e d i n m e t h a n o l (10 mL) a n d t h e f i n a l v o l u m e made up t o 250 mL w i t h m e t h a n o l - w a t e r (80:20) i n a v o l u m e t r i c f l a s k . An a l i q u o t o f 50 mL o f t h i s s o l u t i o n was a n a l y z e d f o r r e s i n - a n d f a t t y a c i d s a s d e s c r i b e d b e f o r e ( S e c t i o n 3.5.2.1.3) f o r wood a n a l y s i s a b o v e . A n o t h e r a l i q u o t o f 150 mL was d i l u t e d i n 1500 mL o f w a t e r i n o r d e r t o p r e c i p i t a t e t h e l i g n i n . T h i s l i g n i n was q u a n t i f i e d i n a s i m i l a r way as f o r " L i g n i n S" (See S e c t i o n 3.5.2) a n d a l s o t a k e n f o r GPC a n a l y s i s . D u r i n g t h i s S o x h l e t e x t r a c t i o n w i t h m e t h a n o l , t h e e x t r a c t i v e s a n d l i g n i n were r e f l u x e d f o r 54 h. Due t o t h e p o s s i b i l i t y o f l i g n i n r e c o n d e n s a t i o n a known l i g n i n s a m p l e was t a k e n f o r c o m p a r i s o n . A s a m p l e o f 300 mg o f t h e " L i g n i n S-20" (M w= 1390 a n d M n= 678) was r e f l u x e d w i t h 160 mL o f m e t h a n o l as m e n t i o n e d a b o v e . The r e s u l t i n g l i g n i n s o l u t i o n was c o n c e n t r a t e d u n d e r vacuum t o ~15 mL a n d t h e n d i l u t e d w i t h 150 mL o f w a t e r i n o r d e r t o p r o v o k e p r e c i p i t a t i o n o f t h e l i g n i n . T h i s l i g n i n was f i l t e r e d on a m i c r o p o r e f i l t e r , a i r d r i e d o v e r n i g h t , t h e n f r e e z e - d r i e d f o r 24 h a n d f i n a l l y t a k e n f o r GPC a n a l y s i s . C o m p a r i s o n o f 77 t h e o r i g i n a l " L i g n i n S-20" a n d t h e one a f t e r r e f l u x i n g s howed t h e same M w a n d M n v a l u e s , i . e . , no r e c o n d e n s a t i o n o c c u r r e d due t o h e a t i n g ( r e f l u x i n g ) i n m e t h a n o l . 3.5.2.4. Complementary analysis of l i g n i n from the high pressure 60 min pulping C o m p l e m e n t a r y a n a l y s e s were p e r f o r m e d on t h e r e s i n -a n d f a t t y a c i d s a m p l e s o f t h e m o t h e r b l a c k l i q u o r , t h e p r e c i p i t a t e d l i g n i n a n d t h e p u l p o b t a i n e d a f t e r 60 m i n c o o k i n g . C o n t r a r y t o t h e f r a c t i o n a t i o n p r o c e d u r e f o l l o w e d f o r t h e e x t r a c t i v e s a n a l y s e s a f t e r t h e 20, 40 a n d 60 m i n c o o k i n g , a d i l u t i o n o f t h e m o t h e r b l a c k l i q u o r w i t h w a t e r (1:10 r a t i o ) r e n d e r e d a n o t h e r t y p e o f l i g n i n ("Lignin II") . T h i s "Lignin I I " was i s o l a t e d , f r e e z e - d r i e d ( S e c t i o n 3.5.2.) a n d t a k e n f o r f u r t h e r m o l e c u l a r w e i g h t d i s t r i b u t i o n a n a l y s i s b y s i z e e x c l u s i o n c h r o m a t o g r a p h y on an HPLC ( S e c t i o n 3 . 6 . 1 ) . R e s i n - a n d f a t t y a c i d s w e re i s o l a t e d , i d e n t i f i e d a n d q u a n t i f i e d i n t h e b l a c k l i q u o r ( S e c t i o n 3.5.2.1.3) a n d i n t h e l i g n i n ( S e c t i o n 3 . 5 . 2 . 2 ) . T h e s e e x t r a c t s were r e a d y f o r GC a n d GC-MS a n a l y s e s . 78 3.5.3. Normal pressure organosolv pulping N o r m a l p r e s s u r e p u l p i n g p e r f o r m e d a t a u t o g e n o u s p r e s s u r e s d e v e l o p e d b y t h e 8 0 : 2 0 c o o k i n g l i q u o r was c o n d u c t e d as a c o m p l e m e n t a r y e x p e r i m e n t t o t h e h i g h p r e s s u r e t r i a l s . B o t h n o r m a l a n d h i g h p r e s s u r e p u l p i n g w e r e c o n d u c t e d i n a s i m i l a r m a n n e r . T h e b l a c k l i q u o r a n d t h e p u l p were h a n d l e d as d e s c r i b e d b e f o r e ( S e c t i o n s 3 . 5 . 2 . 1 . a n d 3 . 5 . 2 . 3 . ) . A n a n a l y t i c a l scheme i s o u t l i n e d i n F i g . 1 2 b . F o r t h e n o r m a l p r e s s u r e p u l p i n g , t h e c o o k e d c h i p s w e r e r e m o v e d f r o m t h e v e s s e l , w a s h e d w i t h a c e t o n e (30 m L ) , a n d t h e n w i t h m e t h a n o l (30 mL) a n d w a t e r (40 mL) . The b l a c k l i q u o r a n d t h e wash f r a c t i o n s were c o l l e c t e d as t h e " i n i t i a l black liquor". On s t a n d i n g o v e r n i g h t a l i g n i n ("Precipitated Lignin") p r e c i p i t a t e d f r o m t h i s b l a c k l i q u o r w h i c h was i s o l a t e d a n d s a v e d f o r GPC a n a l y s i s . The r e s i d u a l b l a c k l i q u o r was c a l l e d " B l a c k L i q u o r R " . T h e c o o k e d c h i p s were d i s i n t e g r a t e d i n a 250 mL W a r i n g b l e n d e r w i t h a c e t o n e (80 mL) f o r one m i n u t e a n d t h e r e s u l t i n g f i b e r s were c o l l e c t e d on a 15 cm B u c h n e r f u n n e l ( p r e - w e i g h e d f i l t e r p a p e r was u s e d ) a n d w a s h e d t w i c e w i t h a c e t o n e (40 mL) a n d w a t e r (30 mL) a n d f i n a l l y w i t h 30 mL o f a c e t o n e . On s t a n d i n g o f t h i s f i l t r a t e a new amount o f l i g n i n p r e c i p i t a t e d ("Entrapped Lignin") w h i c h was i s o l a t e d a n d t a k e n f o r GPC a n a l y s i s . Decan t / Washing Black Liquor + Lignin + Extract ives + Pulping " I n i t i a l Black Liquor" + Lignin + Extractives Precipitated Lignin GPC Filtration " Black Liquor R" + Lignin + Extractives L i q - L i q Ext. (Et 20) Dissolved Lignin Washings + Extractives + Lignin Filtrat ion Residual Washings + Extractives Extract ives GPC Chips (Lignin + Extract ives) B l e n d i n g / Washing Pulp + Entrapped Lignin + Extract ives ^/'^Washing F i l t r a t i o n / Washing Pulp + Extract ives Trapped Lignin GPC Fiaure 12b Flow diagram f o r the recovery, i d e n t i f i c a t i o n and q u a n t i f i c a t i o n of Figure H D . * X O ^ ^ ^ L I Q U Q R A N D P U L P A F F C E R N O R M A L pressure organosolv pulping of slash pine wood 80 A f t e r t h e l i q u i d - l i q u i d e x t r a c t i o n o f t h e r e s i n - a n d f a t t y a c i d s f r o m t h e " B l a c k L i q u o r R", a s m a l l f r a c t i o n o f l i g n i n ("Dissolved Lignin") p r e c i p i t a t e d o u t o f t h e s o l v e n t s y s t e m . P r e c i p i t a t i o n o f t h i s l i g n i n t y p e may be c a u s e d i n p a r t b y t h e h i g h e r w a t e r c o n c e n t r a t i o n p r e s e n t a t t h e e n d o f t h e e x t r a c t i o n . A g a i n , t h i s l i g n i n was i s o l a t e d a n d t a k e n f o r GPC a n a l y s i s . 3.6. Molecular Weight D i s t r i b u t i o n of Lignins A f t e r High  Pressure Pulping I n summary, d i f f e r e n t l i g n i n s w e r e o b t a i n e d a f t e r p u l p i n g b a s e d on t h e i r s o l u b i l i t y . A l i g n i n w h i c h p r e c i p i t a t e s on s t a n d i n g o f t h e "mother black l i q u o r " was c a l l e d "Lignin I". A s e c o n d t y p e o f l i g n i n , w h i c h r e m a i n e d i n s o l u t i o n a f t e r t h e f i l t r a t i o n o f "Lignin I", was d e s i g n a t e d "Lignin S". T h e s e s o l u b l e l i g n i n t y p e s w e re t h e l i g n i n s S-20, S-40 a n d S-60 o b t a i n e d a f t e r t h e 20, 40 a n d 60 m i n p u l p i n g e x p e r i m e n t s . A t h i r d t y p e o f l i g n i n ("Lignin P") was c o - r e m o v e d f r o m t h e p u l p a f t e r S o x h l e t e x t r a c t i o n o f t h e p u l p e x t r a c t i v e s w i t h m e t h a n o l . F i n a l l y , b y u s i n g a d i f f e r e n t p r o c e d u r e f o r p r e c i p i t a t i o n o f t h e l i g n i n i n t h e b l a c k l i q u o r , n a m e l y a d i l u t i o n o f t h e w h o l e b l a c k l i q u o r i n w a t e r (1:10 r a t i o ) , r e n d e r e d t h e new t y p e "Lignin I I " . L i g n i n I I c o n t a i n s L i g n i n I a n d L i g n i n S. 81 M o l e c u l a r w e i g h t d i s t r i b u t i o n s o f t h e s e l i g n i n s w e r e d e t e r m i n e d b y s i z e e x c l u s i o n c h r o m a t o g r a p h y on an HPLC. 3.6.1. GPC Analysis 3.6.1.1. GPC conditions The m o l e c u l a r w e i g h t d i s t r i b u t i o n (MWD) o f t h e d i f f e r e n t l i g n i n s o b t a i n e d a f t e r o r g a n o s o l v p u l p i n g was e s t i m a t e d b y u s i n g a s i z e e x c l u s i o n c h r o m a t o g r a p h i c m e t h o d . A l l l i g n i n s a m p l e s w e r e d i s s o l v e d i n t e t r a h y d r o f u r a n (THF) a t 0.5% (w/v) f o r i n j e c t i o n s i n t o t h e HPLC. The i n s t r u m e n t s e t t i n g was a s f o l l o w s : A HPLC s y s t e m e q u i p p e d w i t h an I s o c r a t i c S p e c t r a P h y s i c s H8810 Pump, a R h e o d y n e 7125 i n j e c t o r l o o p , a GH8P g u a r d c o l u m n , a n d f o u r 30 cm l o n g a n a l y t i c a l TSK H c o l u m n s i n s e r i e s (1000H, 2500H, 3000H a n d 4000H c o n t a i n i n g s p h e r i c a l , c r o s s - l i n k e d p o l y s t y r e n e / d i v i n y l b e n z e n e p a r t i c l e s o f 8 t o 10 |im d i a m e t e r , p a c k e d i n t e t r a h y d r o f u r a n ) . T e t r a h y d r o f u r a n was t h e e l u e n t , a n d t h e e l u t i n g l i g n i n f r a c t i o n s were m o n i t o r e d b y m e a s u r i n g t h e a b s o r b a n c e a t 280 nm w a v e l e n g t h u s i n g a K r a t o s S p e c t r o f l o w 757 UV/VIS d e t e c t o r . O u t p u t s i g n a l was t r a n s f e r r e d t o a S p e c t r a P h y s i c s 4290 i n t e g r a t o r - p l o t t e r . 82 3.6.1.2. C a l i b r a t i o n curve C a l i b r a t i o n o f t h e s i z e e x c l u s i o n c h r o m a t o g r a p h y c o l u m n s b a s e d on r e l a t i v e e l u t i o n t i m e ( V R ) was o b t a i n e d b y u s i n g t h e p o l y s t y r e n e s t a n d a r d s o f d i f f e r e n t m o l e c u l a r w e i g h t s . Out o f t h e m e a s u r e d v a l u e s o f m o l e c u l a r w e i g h t d i s t r i b u t i o n , w e i g h t a v e r a g e m o l e c u l a r w e i g h t (M w) a n d number a v e r a g e m o l e c u l a r w e i g h t (M n) were c a l c u l a t e d b y i n s t r u m e n t p r o c e d u r e . R e p l o t t i n g o f t h e d e t e c t o r r e s p o n s e s b y u s i n g t h e MTS m a i n f r a m e g r a p h i c s p a c k a g e TELLAGRAF, e n a b l e s e a s i e r i n t e r p r e t a t i o n a n d d i f f e r e n t i a t i o n o f t h e v a r i o u s l i g n i n t y p e s . 3.6.1.3. GPC Injections A l l o r g a n o s o l v l i g n i n s o b t a i n e d w e re r e a d i l y s o l u b l e i n t e t r a h y d r o f u r a n ( T H F ) . T h e r e f o r e , t h e r e was no n e e d t o d e r i v a t i z e t h e l i g n i n s a m p l e s . E a c h i n j e c t i o n s a m p l e c o n s i s t e d o f a 20 UX o f t h e 0.5% (w/v) l i g n i n s o l u t i o n i n THF. A l l a n a l y s e s w e re p e r f o r m e d a t a f l o w r a t e o f 1.0 mL/min o f THF. A minimum o f t h r e e r e p l i c a t e s f o r e a c h i n d i v i d u a l l i g n i n t y p e was t a k e n f o r t h e s e a n a l y s e s . 83 4. RESULTS AND DISCUSSION 4.1. Wood Species The g e n e r i c c o m p o s i t i o n o f s l a s h p i n e (Pinus e l i o t t i i Engelm.) wood e x t r a c t i v e s h a s b e e n d e s c r i b e d e a r l i e r i n t h e l i t e r a t u r e b y Z i n k e l a n d F o s t e r (1980) . A c c o r d i n g l y , c o n f i r m a t o r y q u a l i t a t i v e a n d q u a n t i t a t i v e a n a l y s e s were p e r f o r m e d on t h e wood e x t r a c t i v e s o f t h i s s p e c i e s . A l t h o u g h c o n s i d e r a b l e work h a s b e e n done on t h e c h e m i c a l c o m p o s i t i o n o f t h e e x t r a c t i v e s o f most c o n i f e r s , n o t h i n g h a s b e e n p u b l i s h e d on t h e b e h a v i o u r o f s u c h e x t r a c t i v e s d u r i n g o r g a n o s o l v ( s o l v e n t ) p u l p i n g t h u s f a r . The b a s e l i n e c h e m i c a l c o m p o s i t i o n o f t h e wood s a m p l e u s e d f o r t h i s s t u d y was i n v e s t i g a t e d . T h e r e b y , t h e c h e m i c a l c o m p o s i t i o n o f i t s f a t t y a c i d a n d r e s i n a c i d f r a c t i o n s c o u l d be c o m p a r e d t o t h o s e f o u n d i n t h e l i t e r a t u r e ( T a b l e 5 a n d 6, r e s p e c t i v e l y ) . F o r c o m p a r i s o n t h e t a l l o i l c o m p o s i t i o n o f s o u t h e r n p i n e sapwood a n d b l a c k l i q u o r e x t r a c t i v e s i s a l s o r e p r o d u c e d i n T a b l e 7 . The i n f o r m a t i o n t h u s d e r i v e d was v e r y h e l p f u l i n f u r t h e r a s s e s s i n g t h e e x t r a c t i v e v a l u e s f o r t h e e x p e r i m e n t a l wood s a m p l e a n d c o m p a r i n g t h e m t o t h o s e r e p o r t e d i n t h e l i t e r a t u r e . P a r t i c u l a r l y , c o n f i r m a t o r y a n a l y s e s w e re p e r f o r m e d on t h e wood e x t r a c t i v e s o f s l a s h p i n e t o v a l i d a t e e a r l i e r f i n d i n g s o f Z i n k e l a n d F o s t e r 84 (1980) a n d t o s t u d y t h e b e h a v i o u r o f i t s e x t r a c t i v e s d u r i n g o r g a n o s o l v p u l p i n g . The known c h e m i c a l c o m p o s i t i o n o f e x t r a c t i v e s o f t h i s s p e c i e s f a c i l i t a t e d a d e q u a t e c o n t r o l i n f o l l o w i n g t h e f a t e o f e x t r a c t i v e s n o t e d f o r t h i s s p e c i e s . T h i s f a c t a l s o a i d e d i n s e l e c t i o n a n d d e v e l o p m e n t o f t h e a p p r o p r i a t e i s o l a t i o n m e t h o d o l o g y f r o m t h e c o o k i n g l i q u o r . 4 . 2 . Chemical Analysis of Wood The m a j o r p o r t i o n o f wood i n g e n e r a l i s c o m p r i s e d o f p o l y s a c c h a r i d e s a n d l i g n i n . A c c o m p a n i n g t h e s e c o m p o n e n t s , s m a l l amounts o f e x t r a c e l l u l a r , s o c a l l e d " e x t r a n e o u s " c o m p o n e n t s a r e a l s o f o u n d i n p r a c t i c a l l y a l l woods. T h e s e e x t r a n e o u s c o m p o n e n t s c o m p r i s e s u b s t a n c e s t h a t c a n be r e m o v e d f r o m t h e wood b y n e u t r a l o r g a n i c s o l v e n t s . D u r i n g c h e m i c a l p u l p i n g , wood i s t r e a t e d w i t h c h e m i c a l s ( i n o r g a n i c o r o r g a n i c ) a t h i g h t e m p e r a t u r e a n d p r e s s u r e i n o r d e r t o d i s s o l v e a s much l i g n i n a s p o s s i b l e f r o m t h e c e l l w a l l a n d t h e c o n n e c t i n g ( m i d d l e l a m e l l a ) z o n e s . T h i s l e a v e s t h e c e l l u l o s i c p o r t i o n ( p u l p ) a s t h e r a w m a t e r i a l f o r p a p e r m a k i n g . D i s s o l u t i o n o f t h e l i g n i n d u r i n g p u l p i n g i s a c c o m p a n i e d a l s o b y s o l u b i l i z a t i o n o f t h e e x t r a c t i v e c o m p o n e n t s p r e s e n t i n wood. I n o r d e r t o s t r i k e a mass 85 b a l a n c e o f t h e l i g n i n a n d e x t r a c t i v e s p r e s e n t i n wood, i t was r e q u i r e d t o i m p l e m e n t q u a n t i t a t i v e d e t e r m i n a t i o n s o f t h e v a r i o u s e n t i t i e s i n t h e s l a s h p i n e s a m p l e . 4.2 .1.Determination of wood extractives i n the slash pine  sample S i n c e s t u d y o f t h e b e h a v i o u r o f t h e e x t r a c t i v e s d u r i n g o r g a n o s o l v p u l p i n g was o f i n t e r e s t , i t was n e c e s s a r y t o c h a r a c t e r i z e t h e r e s i n - a n d f a t t y a c i d s i n p a r t i c u l a r b e f o r e a n d a f t e r t h e p u l p i n g p r o c e s s . F u r t h e r , i t was a l s o n e c e s a r y t o f i n d a p r o p e r p r o c e d u r e f o r t h e i r q u a n t i t a t i v e r e m o v a l f r o m b o t h t h e wood a n d s p e n t c o o k i n g l i q u o r w i t h o u t i n f l u e n c i n g t h e i r c o n t e n t a n d / o r c h e m i c a l s t r u c t u r e . The f i r s t c o n c e r n d u r i n g t h e q u a l i t a t i v e a n d / o r q u a n t i t i v e d e t e r m i n a t i o n o f t h e e x t r a c t i v e s was t h e e f f e c t o f h e a t u p o n t h e i r d e g r a d a t i o n . I t was f i r s t e x p e c t e d t h a t e l e v a t e d t e m p e r a t u r e s m i g h t d e g r a d e (change) some o f t h e e x t r a c t i v e s . F o r t h i s r e a s o n , c o l d m e t h a n o l m a c e r a t i o n e x t r a c t i o n was c o m p a r e d w i t h S o x h l e t e x t r a c t i o n i n w h i c h h o t m e t h a n o l i s c y c l e d b e t w e e n t h e b o i l i n g r e s e r v o i r f l a s k a n d t h e e x t r a c t i o n chamber ( b a r r e l ) . Thus t h e e x t r a c t i v e s r e m o v e d f r o m t h e wood a r e e x p o s e d t o b o i l i n g s o l v e n t i n t h e s o l v e n t r e s e r v o i r o r r o u n d b o t t o m f l a s k . 86 The t o t a l e x t r a c t i v e s c o n t e n t o f t h e wood a f t e r 6 w eeks o f s t o r a g e o b t a i n e d b y t h e m e t h a n o l m a c e r a t i o n e x t r a c t i o n was 4.2% ( a v e r a g e o f t h r e e r e p l i c a t e d e t e r m i n a t i o n s ) a n d b y t h e m e t h a n o l S o x h l e t e x t r a c t i o n 4.3%. F r o m t h e s e e x p e r i m e n t s i t was f o u n d t h a t t h e m e t h o d o f e x t r a c t i o n h a d no s i g n i f i c a n t e f f e c t on t h e q u a l i t y a n d q u a n t i t y o f e x t r a c t i v e s i n t h e s a m p l e a s d e t e r m i n e d b y t h e m a c e r a t i o n a n d h o t S o x h l e t e x t r a c t i o n t e c h n i q u e s . T h e r e f o r e , i t c a n be s t a t e d t h a t h e a t i n g d i d n o t c a u s e d e g r a d a t i o n o f t h e e x t r a c t i v e s d u r i n g t h e i r r e m o v a l f r o m wood. F u r t h e r m o r e , b o t h t h e m e t h a n o l m a c e r a t i o n a n d m e t h a n o l S o x h l e t e x t r a c t i o n s w e re c o m p a r e d a g a i n s t a s t a n d a r d e t h a n o l - b e n z e n e (1:2) S o x h l e t e x t r a c t i o n , c o n d u c t e d a c c o r d i n g t o TAPPI s t a n d a r d T 204 o s - 7 6 . The c o n t e n t f r o m t h e l a t t e r e x t r a c t i o n was 3.9%, w h i c h i s s l i g h t l y l o w e r t h a n t h a t f o u n d i n t h e p r e v i o u s e x t r a c t i o n m o d a l i t i e s . Q u a n t i f i c a t i o n o f t h e e x t r a c t i v e s p r e s e n t i n wood i s a v e r y d i f f i c u l t t a s k . I t must c o n s i d e r n o t o n l y f a c t o r s w h i c h c a n a f f e c t t h e i r c o n t e n t i n t h e s t a n d i n g t r e e , b u t a l s o f a c t o r s t h a t c a n i n f l u e n c e t h e m e t h o d o l o g y u s e d f o r t h e i r q u a n t i f i c a t i o n . I t i s known t h a t b i o l o g i c a l f a c t o r s l i k e t h e m onth o f f e l l i n g ( B i s h o p a n d M a r c k w o r t h , 1 9 3 3 ) , e n v i r o n m e n t , g e n e t i c v a r i a t i o n s ( S t a n l e y , 1 9 6 9 ) , g e o g r a p h i c a l l o c a t i o n (Swan, 1968) , s e a s o n i n g ( A s s a r s s o n , 87 1969; S p r i n g e r , 1978) , p a r t o f t h e t r e e ( L o r b e e r a n d K r a t z l , 1985) a n d age ( S t a n l e y , 1969) h a v e n o t i c e a b l e e f f e c t s on t h e e x t r a c t i v e c o n t e n t i n d i f f e r e n t woods. I n a d d i t i o n t o t h e p r e v i o u s c o n s i d e r a t i o n s , i t i s v e r y i m p o r t a n t t o know t h e c o n d i t i o n s o f s t o r a g e a n d t h e e l a p s e d t i m e b e t w e e n t h e c u t t i n g a n d t h e e x e c u t i o n o f t h e c h e m i c a l a n a l y s i s . 4.2.2. Lignin from wood The a v e r a g e a c i d - i n s o l u b l e l i g n i n ( K l a s o n l i g n i n ) c o n t e n t o f a r e p r e s e n t a t i v e s a m p l e f o u n d i n s l a s h p i n e wood was 2 6.8 %. The l i g n i n c o n t e n t was d e t e r m i n e d a c c o r d i n g t o TAPP I s t a n d a r d T 222 o s - 7 6 . S i n c e some l i g n i n i s a l s o s o l u b i l i z e d i n h i g h l y c o n c e n t r a t e d a c i d s ( i . e . H 2 S 0 4 a t 7 2 % ) , t h e t o t a l l i g n i n was d e t e r m i n e d b y a d d i n g t h e a c i d - s o l u b l e l i g n i n (UV l i g n i n ) t o t h e K l a s o n l i g n i n . The a c i d - s o l u b l e l i g n i n was 1.4%. T h e r e f o r e , t h e t o t a l l i g n i n , w h i c h i s t h e sum o f K l a s o n a n d UV l i g n i n , was 2 8 . 2 % . 88 4 . 3 . P r e l i m i n a r y S t u d i e s f o r t h e A n a l y s i s o f R e s i n - and  F a t t y A c i d s 4 . 3 . 1 . Gas c h r o m a t o g r a p h i c s t u d i e s D u r i n g s p l i t l e s s i n j e c t i o n , t h e s o l v e n t s e l e c t e d f o r i n j e c t i o n must f u l f i l l some b a s i c c o n s i d e r a t i o n s . T h e s e s h o u l d i n c l u d e t h e a b i l i t y t o d i s s o l v e t h e s a m p l e , t o p r o v i d e a g o o d " s o l v e n t effect", a n d t o be c o m p a t i b l e w i t h t h e c o l u m n s t a t i o n a r y p h a s e . The most w i d e l y u s e d s o l v e n t s f o r s p l i t l e s s i n j e c t i o n a r e : d i c h l o r o m e t h a n e , c h l o r o f o r m , c a r b o n d i s u l f i d e , d i e t h y l e t h e r , n - h e x a n e a n d i s o - o c t a n e ( F r e e m a n , 1 9 8 1 ) . I n a d d i t i o n t o t h e b a s i c c o n s i d e r a t i o n s , s e l e c t i o n o f CH2CI2 a s t h e s o l v e n t f o r i n j e c t i o n was b a s e d on i t s l o w e r b o i l i n g p o i n t ( 4 0 Q C ) . T h i s c h a r a c t e r i s t i c r e n d e r e d g o o d c h r o m a t o g r a m s w i t h m i n o r s o l v e n t t a i l i n g a n d was s u i t a b l e f o r q u a n t i t a t i v e c a l c u l a t i o n s b y t h e i n t e g r a t o r . I t must be a d d e d t h a t q u a n t i f i c a t i o n o f r e s i n a c i d s was n o t j e o p a r d i z e d b y t h e s o l v e n t t a i l i n g s i n c e t h e s e a c i d s e l u t e q u i t e l a t e i n t h e c h r o m a t o g r a m ( a f t e r 40 m i n u t e s i n t h e HP-5 c a p i l l a r y c o l u m n ) . I n t h e c a s e o f t h e f a t t y a c i d s , e v e n t h o u g h t h e y emerge q u i t e e a r l y i n t h e c h r o m a t o g r a m ( a f t e r 5 m i n i n t h e DB 225 megabore c o l u m n ) , no i n t e r f e r e n c e b y t h e s o l v e n t p e a k was d e t e c t e d . Q u a n t i t a t i v e a n a l y s e s w e r e p e r f o r m e d b y u s i n g t h e i n t e r n a l s t a n d a r d m e t h o d . T h i s m e t h o d d o e s n o t r e q u i r e 89 e i t h e r e x a c t o r c o n s i s t e n t s a m p l e v o l u m e n o r c o n s i s t e n t r e s p o n s e f a c t o r s s i n c e t h e l a t t e r a r e b u i l t i n t o t h e m e t h o d . T h i s m e t h o d i s v e r y u s e f u l i f r e p r o d u c i b i l i t y i s a p r o b l e m , a n d i n s i t u a t i o n s w h ere one d o e s n o t want t o p e r f o r m f r e q u e n t r e c a l i b r a t i o n s . The i n t e r n a l s t a n d a r d c h o s e n f o r t h i s m e t h o d c a n n o t be a c omponent o f t h e s a m p l e , a n d a known amount o f i t i s a d d e d t o e a c h s a m p l e . A c c o r d i n g t o M i l l e r (1988) e v e r y i n t e r n a l s t a n d a r d s h o u l d meet s e v e r a l c r i t e r i a : " - I t s h o u l d e l u t e n e a r t h e p e a k s o f i n t e r e s t , - I t must be w e l l r e s o l v e d f r o m them, - I t s h o u l d be c h e m i c a l l y s i m i l a r t o t h e a n a l y t e s o f i n t e r e s t a n d n o t r e a c t w i t h any s a m p l e c o m p o n e n t s , a n d - L i k e any s t a n d a r d , i t must be a v a i l a b l e i n p u r e f o r m " . C h r o m a t o g r a p h i c a n a l y s e s w e re b a s e d on t h e p r o c e s s o f m e a s u r i n g t h e p e a k a r e a s w h i c h c o n s i s t e d o f i n t e g r a t i n g t h e a r e a u n d e r t h e p e a k s . T h i s p r o c e s s a l s o c o n v e r t s a n a l o g s i g n a l s i n t o a d i g i t a l s i g n a l n e c e s s a r y f o r c o m p u t e r c a l c u l a t i o n s . A l l r e s i n - a n d f a t t y a c i d s were m e t h y l a t e d b e f o r e GC a n d GC-MS a n a l y s i s . T h e r e i s a c h o i c e o f a number o f r e a g e n t s f o r m e t h y l a t i o n b u t s p e c i f i c a t i o n s f o r q u a n t i t a t i v e c o n v e r s i o n s h a v e n o t b e e n d e f i n e d . Among t h e s e s p e c i f i c a t i o n s , t i m e o f r e a c t i o n a n d s o l v e n t f o r m e t h y l a t i o n w e re i n c o n s i s t e n t , a n d i n v e s t i g a t i o n s f o r 90 a s c e r t a i n i n g t h e b e s t c o n d i t i o n s w e re n e c e s s a r y t o f u l l y d e v e l o p a r e l i a b l e a n d r e p r o d u c i b l e m e t h o d . 4.3.1.1. Time se l e c t i o n f o r methylation P r e p a r a t i o n o f m e t h y l e s t e r s ( c o m p l e t e m e t h y l a t i o n ) i s an i m p o r t a n t a s p e c t o f i d e n t i f i c a t i o n a n d c h a r a c t e r i z a t i o n o f t h e wood e x t r a c t i v e s . C o n s i d e r a b l e e f f o r t s w e r e e x p a n d e d i n t h i s s t u d y t o s e l e c t t h e optimum c o n d i t i o n s f o r d e r i v a t i z a t i o n o f t h e e x t r a c t i v e s a t h a n d . The m e t h o d o f de B o e r a n d B a c k e r (1963) h a s b e e n c o n f i r m e d t o g i v e g o o d r e s u l t s when d i a z o m e t h a n e was u s e d a s t h e m e t h y l a t i o n a g e n t . I n o r d e r t o a s c e r t a i n t h e t i m e f o r c o m p l e t i o n o f t h e m e t h y l a t i o n r e a c t i o n f o r t h e r e s i n - a n d f a t t y a c i d s , a s e r i e s o f m e t h y l a t i o n s w e re p e r f o r m e d w h e r e t h e r e a c t i o n was a l l o w e d t o p r o c e e d f o r 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, a n d 5.0 m i n . D e h y d r o a b i e t i c a c i d was c h o s e n a s t h e t e s t r e s i n a c i d f o r t h i s e x p e r i m e n t . C o m p a r i s o n s w ere b a s e d on t h e r a t i o s o f t h e r e s p o n s e a r e a s o f t h e t e s t r e s i n a c i d r e l a t i v e t o t h e r e s p o n s e a r e a o f an i n t e r n a l s t a n d a r d ( m e t h y l h e p t a d e c a n o a t e ) . R e s u l t s o f t h e s e r a t i o c o m p a r i s o n s a r e r e p o r t e d i n T a b l e 10. From t h i s t a b l e i t c a n be s e e n t h a t a t r e a c t i o n t i m e s l o n g e r t h a n 3.0 m i n t h e r a t i o t e s t i n g show no f u r t h e r i n c r e a s e a n d h e n c e m e t h y l a t i o n c a n be c o n s i d e r e d a s b e i n g 91 c o m p l e t e . Thus t o e n s u r e c o m p l e t e m e t h y l a t i o n o f a l l f u t u r e s a m p l e s a r e a c t i o n t i m e o f 4.0 m i n was c h o s e n . Table 1 0 . Ratio t e s t i n g of the response area of dehydroabietic a c i d r e l a t i v e to the response area of methyl heptadecanoate a f t e r various times of methylation with diazomethane Time (min) A* r e s i n a c i d A i n t . s t d . 1.5 1.20 2.0 1.20 2.5 1.22 3.0 1.28 3.5 1.28 4.0 1.32 4.5 1.31 5.0 1.32 A= R e s p o n s e a r e a . 92 4.3.1.2. Solvent s e l e c t i o n f o r methylation A c c o r d i n g t o Z i n k e l and Han (1986), m e t h y l a t i o n of r e s i n a c i d s c a r r i e d out i n a s i n g l e s o l v e n t i s not as e f f i c i e n t as m e t h y l a t i o n performed i n a mixture of s o l v e n t s . They found t h a t m e t h y l a t i o n i n e i t h e r benzene, t o l u e n e or e t h e r alone was not completed i n a s h o r t time p e r i o d , but the a d d i t i o n o f methanol t o d i e t h y l e t h e r r e s u l t e d i n an instantaneous r e a c t i o n (See Table 9). E s t e r i f i c a t i o n w i t h C H 2 N 2 , l i k e o t h e r r e a c t i o n s , i s g r e a t l y i n f l u e n c e d by s o l v e n t s ( E i s t e r t et al., 1951). Among the p u b l i c a t i o n s t o date d e s c r i b i n g the m e t h y l a t i o n r e a c t i o n , s e v e r a l have d e a l t w i t h the use of ether-methanol (9:1) as the s o l v e n t f o r t h i s r e a c t i o n . I n t r i g u e d by the speed of the r e a c t i o n , an attempt was made t o extend the number of s o l v e n t s s u i t a b l e f o r m e t h y l a t i o n t o shorten the m e t h y l a t i o n time and assure complete d e r i v a t i z a t i o n . Methanol/dichloromethane was chosen as an a l t e r n a t i v e . Methanol was chosen because i t was the s o l v e n t used f o r organosolv p u l p i n g and because of the good r e s u l t s t h a t Z i n k e l and Han (1986) and Schlenk and Gellerman(1960) had with i t as a c o - s o l v e n t . On the other hand, dichloromethane was chosen because i t i s i n c l u d e d among the good s o l v e n t s f o r s p l i t l e s s i n j e c t i o n (Freeman, 93 1981) . D i c h l o r o m e t h a n e h a s a l s o b e e n s u g g e s t e d a s g o o d s o l v e n t f o r m e t h y l a t i o n (Hopps, 1974) . F r om t h e a b o v e i n f o r m a t i o n , i t was d e c i d e d t o t e s t t h e b e s t s o l v e n t e f f e c t ( o r m i x t u r e ) o f e t h e r - m e t h a n o l ( 9 : 1 ) , d i c h l o r o m e t h a n e : m e t h a n o l (9:1) a n d m e t h a n o l a l o n e . R e s u l t s o f t h e s e m e t h y l a t i o n s t u d i e s a r e g i v e n i n T a b l e 1 1 . I n s p e c t i o n o f T a b l e 11 r e v e a l s t h a t t h e b e s t r e s p o n s e f a c t o r s f o r t h e d e h y d r o a b i e t a t e , a b i e t a t e a n d p a l m i t a t e m e t h y l e s t e r s w e r e t h o s e o b t a i n e d when t h e m e t h y l a t i o n was c a r r i e d o u t i n d i c h l o r o m e t h a n e - m e t h a n o l ( 9 : 1 ) . A l o w r e s p o n s e f a c t o r i n d i c a t e s a h i g h e r r e a c t i o n r a t e . The r e s u l t s o f t h e t h r e e a c i d m o d e l s c h o s e n c l e a r l y d e m o n s t r a t e t h a t t h e m i x t u r e o f d i c h l o r o m e t h a n e - m e t h a n o l (9:1) i s a b e t t e r c h o i c e a s a s o l v e n t m i x t u r e f o r m e t h y l a t i o n o f r e s i n - a n d f a t t y a c i d s t h a n t h e e t h e r -m e t h a n o l p r e v i o u s l y r e p o r t e d i n t h e l i t e r a t u r e ( Z i n k e l a n d Han, 1986) . S i n c e i t was a l s o f o u n d t h a t d i c h l o r o m e t h a n e i s t h e b e s t a l t e r n a t i v e a s t h e s o l v e n t f o r i n j e c t i o n Table 11 . Response factors of p a l m i t i c - , dehydroabie t ic - and a b i e t i c ac ids a f t e r methylation i n 3 solvents Cone. ( n g / j i L ) R e s p o n s e F a c t o r s Et 2 0-CH 3 OH (9:1) CH2CI2-CH3OH (9:1) CH3OH P a l m i t i c D e h y d r o a b i e t i c A b i e t i c 50 40 40 4.70 x 10~4 3.47 x 10~4 4.51 x 10~4 4.45 x 10"4 3.25 x 10"4 4.28 x 10"4 4.74 x 10"4 3.56 x 10~4 4.69 x 10~4 * the known amount (or concentration) Response actor - ^ Measured Response (area or height) 95 (See s e c t i o n 4 . 3 . 1 ) i t c a n be c o n c l u d e d t h a t t h e m i x t u r e o f d i c h l o r o m e t h a n e - m e t h a n o l (9:1) n o t o n l y a l l o w s f a s t e r a n d more c o m p l e t e m e t h y l a t i o n o f t h e r e s i n - a n d f a t t y a c i d s , b u t a l s o f a c i l i t a t e s d i r e c t a n a l y s i s b y G C -i n j e c t i o n s w i t h o u t i s o l a t i o n o f t h e s e m e t h y l e s t e r s . Z i n k e l a n d Han (1986) s u g g e s t e d t h a t p r o p e r p r e c a u t i o n s s h o u l d b e o b s e r v e d i n h a n d l i n g m e t h y l a t e d s a m p l e s t o p r e v e n t o x i d a t i v e c h a n g e s . T h e y s u g g e s t e d m e t h y l t e r t - b u t y l e t h e r (MTBE) a s a g o o d p o l a r s o l v e n t , a c c o m p a n i e d b y a d d i t i o n a l f l u s h i n g o f t h e v i a l w i t h n i t r o g e n b e f o r e c l o s i n g i t e v e n f o r v e r y s h o r t p e r i o d s b e f o r e t h e GC a n a l y s i s . T h e y a l s o m e n t i o n t h a t s t o r a g e i n a n o n p o l a r s o l v e n t c a n p r o v o k e o x i d a t i o n - d e h y d r a t i o n r e a c t i o n s o f l e v o p i m a r a t e a n d p a l u s t r a t e m e t h y l e s t e r s a n d l e a d t o f o r m a t i o n o f d e h y d r o a b i e t a t e . N e s t l e r a n d Z i n k e l (1963) p o i n t e d o u t t h a t m e t h y l l e v o p i m a r a t e , t h o u g h q u i t e l a b i l e b o t h c h e m i c a l l y , e . g . i n a c i d m e d i u m , a n d t h e r m a l l y , h a s b e e n f o u n d t o p a s s t h r o u g h t h e c o l u m n u n c h a n g e d b o t h c h e m i c a l l y a n d r e p r o d u c i b l y i n t h e c h r o m a t o g r a p h i c s e n s e . A l s o t h e y f o u n d t h a t when t h i s a c i d was s t o r e d i n c a p p e d v i a l s a s a s o l u t i o n i n n - h e x a n e , s l o w c o n v e r s i o n t o m e t h y l d e h y d r o a b i e t a t e t o o k p l a c e as t h e m a j o r c h a n g e a n d f o u r a d d i t i o n a l p e a k s h a v i n g r e t e n t i o n t i m e s s h o r t e r t h a n m e t h y l l e v o p i m a r a t e were o b s e r v e d . One o f t h e s e p e a k s showed a r e t e n t i o n t i m e s i m i l a r t o t h a t o f p i m a r i c a c i d . 96 U n d e r a l k a l i n e p u l p i n g c o n d i t i o n s t h e p r e d o m i n a n t c h a n g e i n t h e r e s i n a c i d c o m p o s i t i o n was t h e p a r t i a l i s o m e r i z a t i o n o f l e v o p i m a r i c t o a b i e t i c a c i d (Holmbom an d Ekman, 1 9 7 8 ) . 4.3.2. Preparation of c a l i b r a t i o n table Q u a n t i f i c a t i o n o f r e s i n - a n d f a t t y a c i d s was c o n d u c t e d on two d i f f e r e n t c o l u m n s a n d two c a l i b r a t i o n c u r v e s w e re c o n s t r u c t e d . A t h r e e - l e v e l c a l i b r a t i o n c u r v e was b u i l t i n t o t h e i n t e g r a t o r a n d c a l c u l a t i o n s f o r i n d i v i d u a l q u a n t i t a t i o n s w e r e made b y t h e same i n t e g r a t o r . The r e s p o n s e f a c t o r s a n d r e l a t i v e r e s p o n s e a r e a s o f t h e i n d i v i d u a l r e s i n a c i d s w i t h r e s p e c t t o t h e i n t e r n a l s t a n d a r d ( m e t h y l h e p t a d e c a n o a t e ) a r e g i v e n i n T a b l e 12 a n d t h e i r c a l i b r a t i o n c u r v e s c o n s t r u c t e d i n F i g . 13. D a t a f o r t h e c o n s t r u c t i o n o f t h e c a l i b r a t i o n c u r v e f o r t h e f a t t y a c i d s i s g i v e n i n T a b l e 13 a n d t h e c a l i b r a t i o n c u r v e s a r e f o u n d i n F i g . 14. B o t h r e s i n - a n d f a t t y a c i d s p r o v i d e l i n e a r r e s p o n s e s w i t h i n t h e r a n g e s e x p e c t e d f o r P. e l l i o t t i i . 97 4 . 4 . Analysis of Resin- and Fatty Acids i n Wood A h i g h e x t r a c t i v e - c o n t e n t , t e m p e r a t e s o u t h e r n c o n i f e r wood (Pinus e l l i o t t i i Engelm.) was e x a m i n e d a s a p u l p w o o d s o u r c e b y o r g a n o s o l v p u l p i n g . S i n c e i t was o f i n t e r e s t t o i n v e s t i g a t e t h e b e h a v i o u r o f t h e r e s i n - a n d f a t t y a c i d s d u r i n g t h e l i g n i n s o l v o l y s i s p r o c e s s , i t was n e c e s s a r y t o c h a r a c t e r i z e t h e s e e n t i t i e s n o t o n l y i n t h e wood s a m p l e , b u t a l s o i n t h e b l a c k l i q u o r , p u l p , a n d t h e l i g n i n w h i c h may p r e c i p i t a t e on c o o l i n g o f t h e b l a c k l i q u o r . D i r e c t a n a l y s i s o f t h e r e s i n - a n d f a t t y a c i d s was p e r f o r m e d w i t h o u t p r e v i o u s s e p a r a t i o n ( p u r i f i c a t i o n ) f r o m a v e r y c o m p l e x m i x t u r e s i n c e numerous o t h e r e x t r a c t i v e s a r e a l s o p r e s e n t i n t h e wood. T h i s became f e a s i b l e due t o t h e e x c e l l e n t c h a r a c t e r i s t i c s o f t h e c a p i l l a r y c o l u m n s ( f u s e d - s i l i c a c r o s s - l i n k e d b o n d e d p h a s e i . e . HP-5, 25 m x 0.2 mm x 0.33 Jim) a n d may h a v e b e e n a r e s u l t o f t h e a p p r o p r i a t e t i m e p r o g r a m m i n g f o r t h e GC a n a l y s i s . S u b s t a n t i a l t i m e was s p e n t on m a n i p u l a t i n g t h e c h r o m a t o g r a m f o r a c h i e v i n g s u c h s e p a r a t i o n s . T i m e -t e m p e r a t u r e p r o g r a m m i n g t u r n e d " o u t t o be an e x c e l l e n t means f o r s e p a r a t i n g t h e m a j o r a n d m i n o r e x t r a c t i v e c o n s t i t u e n t s i n t h e s a m p l e s . By t h i s p r o c e d u r e i t became p o s s i b l e t o o b t a i n b e t t e r s e p a r a t i o n o f t h e m a j o r c o m p o n e n t s o f i n t e r e s t . Thus e a c h a n a l y s i s t o o k i n e x c e s s o f 67 m i n t o c o m p l e t e t h e s e p a r a t i o n r e q u i r e d . Table 12 . Response factors and r e l a t i v e response areas of the i n d i v i d u a l major resin acids (as methyl esters) of slash pine with respect to the response area of methyl heptadecanoate L e v e l s 45 ng/ L 68 ng/ L 90 ng/ L RF A r a t i o * RF A r a t i o * RF A r a t i o * P i m a r i c 4.10 E-04 1.19 4.22 E-04 1.92 4.79 E-04 2.55 S a n d a r a c o p i m a r i c 3.10 E-04 1.59 3.73 E-04 2.29 4.03 E-04 3.15 I s o p i m a r i c 3.40 E-04 1.55 3.66 E-04 2.45 3.89 E-04 3.18 P a l u s t r i c 2.73 E-04 . 1.65 3.06 E-04 2.45 4.05 E-04 3.25 D e h y d r o a b i e t i c 3.21 E-04 1.50 3.32 E-04 2.23 4.46 E-04 2.84 A b i e t i c 3.86 E-04 0.84 4.13 E-04 1.27 5.55 E-04 1.57 N e o a b i e t i c 3.93 E-04 1.10 4 .54 E-04 1.57 5. 93 E-04 2.12 vO CO *A ratio= Response a r e a o f r e s i n a c i d Response a r e a o f methyl heptadecanoate Concentration ng/>L Figure 13. C a l i b r a t i o n curves f o r r e s i n acids (as methyl esters) Table 13 . Response factors, relative response factors and relative response areas of the individual major fatty acids (as methyl esters) of slash pine with respect to the response area of methyl heptadecanoate Levels Acids 32 ng/ L 45 ng/ L 65 ng/ L RF R.RF A r a t i o * RF R.RF A r a t i o * RF R.RF A r a t i o Palmitic 2.16 E-4 1.02 1.22 2.28 E-4 1.02 1.63 2.86 E-4 1.04 2.25 Stearic 2.12 E-4 1.00 1.04 2.24 E-4 1.00 1.38 2.74 E-4 1.00 1.94 Ole i c .2.85 E-4 1.34 0.80 3.03 E-4 1.35 1.06 3.72 E-4 1.36 1.48 L i n o l e i c 2.13 E-4 1.01 0.95 2.26 E-4 1.01 1.26 2.79 E-4 1.02 1.75 Li n o l e n i c 3.89 E-4 1.83 0.62 4.11 E-4 1.83 0.83 5.04 E-4 1.84 1.16 Response area of fatty acid *A ratio= Response area of methyl heptadecanoate Concentration ng//iL Figure 14. Ca l i b r a t i o n curves f o r f a t t y acids (as methyl esters) 102 I n e s s e n c e , i n s p i t e o f t h e l o n g c h r o m a t o g r a p h i c t i m e s , t h e s e d i r e c t a n a l y s e s s a v e d t i m e , p r e v e n t e d l o s s e s o f s a m p l e c o m p o n e n t s t h a t m i g h t o c c u r d u r i n g s e p a r a t i o n a n d r e d u c e d t h e r i s k o f p o s s i b l e c h e m i c a l a l t e r a t i o n s ( o x i d a t i o n a n d / o r i s o m e r i z a t i o n ) o f t h e c o m p o n e n t s b y r e a c t i o n s w i t h a c i d s , b a s e s o r o t h e r c h e m i c a l s c u s t o m a r i l y u s e d d u r i n g e x t r a c t i o n o r s e p a r a t i o n o f compounds o f i n t e r e s t i n m i x e d s o l u t i o n s . 4.4.1. Change of extractives i n storage E a r l i e r , r e s e a r c h e r s f o u n d t h a t t h e c o m p o s i t i o n o f e x t r a c t i v e s i n p i n e wood c h a n g e d w i t h p r o l o n g e d s t o r a g e t i m e , i n t h a t c o n c e n t r a t i o n s o f i n d i v i d u a l e x t r a c t i v e s s p e c i e s d e c r e a s e d w h i l e o t h e r s i n c r e a s e d due t o a u t o o x i d a t i o n a n d / o r i s o m e r i z a t i o n ( L a w r e n c e , 1959) . I n o r d e r t o v a l i d a t e e a r l i e r f i n d i n g s on t h e f a t e o f t h e e x t r a c t i v e s d u r i n g s e a s o n i n g , a n d t o s t u d y t h e b e h a v i o u r o f t h e r e s i n - a n d f a t t y a c i d s d u r i n g p u l p i n g , i t became n e c e s s a r y t o c h a r a c t e r i z e t h e r e s i n - a n d f a t t y a c i d s c o n t e n t o f t h e wood a f t e r d i f f e r e n t t i m e p e r i o d s o f s a m p l e s t o r a g e . W i t h t h e p u r p o s e o f d e t e r m i n i n g t h e f a t e o f t h e s e e x t r a c t i v e s d u r i n g s t o r a g e , an i n i t i a l c h a r a c t e r i z a t i o n o f 103 t h e r e s i n - a n d f a t t y a c i d s i n p r o c e s s e d wood s a m p l e s was p e r f o r m e d a f t e r 6 a n d 24 week e x p o s u r e i n t h e CTH room. An a d d i t i o n a l a n a l y s i s o f o n l y t h e r e s i n a c i d s i n wood s a m p l e s a f t e r 52 weeks s t o r a g e a l l o w e d e s t i m a t i o n o f t h e i s o m e r i z a t i o n t e n d e n c i e s o f t h e m a j o r r e s i n a c i d c o n s t i t u e n t s a f t e r t h r e e d i f f e r e n t s t o r a g e i n t e r v a l s , i . e . , 6, 24 a n d 52 we e k s . F i n a l l y , p u l p i n g e x p e r i m e n t s w e r e c a r r i e d o u t w i t h wood s a m p l e s s t o r e d f o r 24 weeks ( a l m o s t 6 m o n t h s ) . The d e l a y i n p u l p i n g ( s t o r a g e f o r 24 weeks) was c h o s e n t o p r o d u c e a s e a s o n e d m a t e r i a l , t h u s l e v e l t h e c h a n g e s w h i c h o c c u r w i t h s e a s o n i n g ( A s s a r s s o n , 1 9 6 9 ) . Thus t h e p i t f a l l o f a s c r i b i n g c h a n g e s i n t h e e x t r a c t i v e s , n o t n e c e s s a r i l y b r o u g h t a b o u t b y t h e p u l p i n g p r o c e d u r e p e r s e , a n d m i s l e a d i n g i n t e r p r e t a t i o n o f t h e r e s u l t s n o r m a l l y o b t a i n e d w i t h f r e s h wood s a m p l e s , was a v o i d e d . I t c a n be ass u m e d t h a t a t t h i s s t a g e ( a f t e r 24 weeks) t h e r e s i n - a n d f a t t y a c i d s w e r e i n t h e i r more s t a b l e f o r m s . 4.4.1.1. Analysis of r e s i n - and f a t t y acids a f t e r 6 weeks of storage S e v e n r e s i n a c i d s a n d f i v e f a t t y a c i d s p r e s e n t i n s l a s h p i n e wood were i d e n t i f i e d on t h e b a s i s o f c o m p a r i s o n o f t h e i r G C - r e t e n t i o n t i m e s w i t h t h o s e o f m o d e l compounds a n d b y GC-MS s p e c t r a . O l e i c , l i n o l e i c a n d l i n o l e n i c a c i d s 104 w e r e n o t i n c l u d e d i n t h e GC-MS s p e c t r a l i d e n t i f i c a t i o n a n d t h e i r i d e n t i f i c a t i o n was b a s e d o n l y on GC r e t e n t i o n t i m e s . Mass s p e c t r a o f r e s i n - a n d f a t t y a c i d s w e r e c o m p a r e d w i t h s p e c t r a f o u n d i n t h e l i t e r a t u r e ( Z i n k e l e t al., 1 9 7 1 ) . Mass s p e c t r a o f t h e r e s i n - a n d f a t t y a c i d s a r e g i v e n i n A p p e n d i x A a n d B, r e s p e c t i v e l y . The G C - c h r o m a t o g r a m o f t h e S o x h l e t m e t h a n o l e x t r a c t s f r o m wood s t o r e d f o r 6 weeks i s shown i n F i g . 15. T h i s c h r o m a t o g r a m was t a k e n w i t h an HP-5 c o l u m n w h i c h p r o p e r l y r e s o l v e d t h e f o l l o w i n g r e s i n a c i d s : p i m a r i c , s a n d a r a c o p i m a r i c , i s o p i m a r i c , p a l u s t r i c , d e h y d r o a b i e t i c , a b i e t i c a n d n e o a b i e t i c a c i d s . Among t h e f a t t y a c i d s o n l y p a l m i t i c a n d s t e a r i c w e r e s e p a r a t e d p r o p e r l y w h i l e o l e i c , l i n o l e i c a n d l i n o l e n i c f a i l e d t o be r e s o l v e d on t h i s c o l u m n . F u r t h e r s t u d i e s o f t h e f a t t y a c i d s w e r e p e r f o r m e d on wood s a m p l e s a f t e r 24 weeks o f s t o r a g e b y u s i n g a DB-225 c a p i l l a r y c o l u m n w h i c h was p u c h a s e d l a t e r . The GC q u a n t i t a t i v e a n a l y s i s o f t h e r e s i n - a n d f a t t y a c i d s w e r e r e l a t e d t o an i n t e r n a l s t a n d a r d a d d e d a t an e a r l y s t a g e i n t h e e x t r a c t i o n p r o c e d u r e . T h e r e f o r e , m i n o r s a m p l e l o s s e s were n o t d e t r i m e n t a l d u r i n g t h e h a n d l i n g o f t h e e x t r a c t s due t o t h e p r e s e n c e o f t h e i n t e r n a l s t a n d a r d . R e s u l t s a r e p r e s e n t e d i n T a b l e 14. Figure 15. Gas chromatogram of the Soxhlet methanol extract from wood stored f o r 6 weeks under CTH room conditions (Resin and f a t t y acids: 1. Palmitic, 2 heptadecanoic, 3 + 4 = mixture of o l e i c , l i n o l e i c and l i n o l e n i c acids', 5! pxmaric, 6. sandaracopimaric, 7. isopimaric, 8. p a l u s t r i c , 9 dehydroabietic, 10. a b i e t i c and 11. neoabietic a c i d s ) . A l l acids were detected as t h e i r methyl ester derivatives 106 Table 14. Resin- and f a t t y a c i d composition of slash pine wood a f t e r 6 weeks of storage (%) a Acids 1 3 Free Combined Total Fatty a c i d s c : 16:0 0.03 0.14 0.17 1 8 : 1 , 18:2, 1 8 : 3 d 0.29 0.84 1.13 18:0 0.02 0.06 0.08 TOTAL 0.34 1.04 1.38 Resin acids: P i m a r i c 0 .11 Sandaracopimaric 0.04 I s o p i m a r i c 0.23 P a l u s t r i c 0.35 D e h y d r o a b i e t i c 0.08 A b i e t i c 0.14 N e o a b i e t i c 0 .09 TOTAL 1. 04 a= Percentages are based on oven-d r i e d wood. b= A c i d s were determined as t h e i r methyl e s t e r s . c= A b b r e v i a t e d n o t a t i o n of f a t t y a c i d s : 16:0= P a l m i t i c a c i d ; 18:1= o l e i c a c i d , 18:2 l i n o l e i c a c i d , 18:3= l i n o l e n i c a c i d , 18:0= s t e a r i c a c i d . d= Mixture of o l e i c , l i n o l e i c and l i n o l e n i c a c i d s . 107 I t i s e v i d e n t f r o m t h e i n f o r m a t i o n g i v e n i n T a b l e 14 t h a t t h e f r e e f a t t y a c i d c o n t e n t i s a l m o s t 2 5 % o f t h e t o t a l f a t t y a c i d c o n t e n t ( f r e e p l u s c o m b i n e d - e s t e r i f i e d -f a t t y a c i d s ) p r e s e n t i n s l a s h p i n e wood. I t c a n a l s o be o b s e r v e d t h a t t h e m a i n f a t c o m p o n e n t s w e r e o f t h e u n s a t u r a t e d t y p e , i . e . , o l e i c , l i n o l e i c a n d l i n o l e n i c a c i d s . /Among t h e r e s i n a c i d s , 6 3 . 5 % b e l o n g t o t h e a b i e t a n e t y p e ( a b i e t i c , n e o a b i e t i c , p a l u s t r i c a n d d e h y d r o a b i e t i c ) , 2 5 . 9 % t o t h e i s o p i m a r a n e t y p e ( i s o p i m a r i c a n d s a n d a r a c o p i m a r i c ) a n d 1 0 . 6 % t o t h e p i m a r a n e t y p e ( p i m a r i c ) ( f o r c h e m i c a l s t r u c t u r e s s e e F i g . 4 a n d 5 ) . P a l u s t r i c a n d i s o p i m a r i c a c i d s a c c o u n t e d f o r a l m o s t 5 6 % o f t h e t o t a l c o n t e n t o f t h e r e s i n a c i d s , w h i l e s a n d a r a c o p i m a r i c was p r e s e n t o n l y i n 4% o f t h e i r c o m b i n e d w e i g h t . The r e l a t i v e p r o p o r t i o n o f t h e most common r e s i n a c i d s p r e s e n t i n s l a s h p i n e wood a f t e r 6 weeks s t o r a g e i s g i v e n i n T a b l e 15. 108 Table 15. Relative proportion of r e s i n acids i n slash pine wood a f t e r 6 weeks of storage 10.6 3.8 22.1 33. 6 7.7 13.5 8.7 100.0 * Percentages are based only on the t o t a l amount of the seven res i n acids characterized i n t h i s study. The r e s i n acid composition i n the combined Soxhlet extracts shows the presence of the most common acids, except levopimaric acid. This finding seems to be contradictory to previous reports (Zinkel and Foster, 1980) which gives a r e l a t i v e proportion of 9.6% for 109 l e v o p i m a r i c a c i d . C o n f i r m a t o r y t e s t s w e r e p e r f o r m e d i n o r d e r t o c o r r o b o r a t e f i n d i n g o f t h e l a c k o f l e v o p i m a r i c a c i d i n t h e wood e x t r a c t . I n d i v i d u a l s a m p l e s o f l e v o p i m a r i c a n d p a l u s t r i c a c i d s , a s w e l l a s t h e m i x t u r e o f t h e t w o a c i d s , w e r e a n a l y z e d b y GC-MS, s i n c e t h e s e two r e s i n a c i d s c o u l d n o t be r e s o l v e d on t h e HP-5 c a p i l l a r y c o l u m n . S p e c t r a l p a t t e r n s f o r t h e s e t w o r e s i n a c i d s a r e s i g n i f i c a n t l y d i f f e r e n t a n d t h e r a t i o o f t h e r e l a t i v e i n t e n s i t i e s o f two p a i r s o f mass p e a k s w e r e t a k e n as p a r a m e t e r s f o r t h e i r d i f f e r e n t i a t i o n . The mass f r a g m e n t a t i o n p a t t e r n o f l e v o p i m a r i c a c i d r e v e a l s h i g h e r i n t e n s i t y o f t h e m/e 239 p e a k (77.71%) c o m p a r e d t o t h e m/e 241 p e a k (32.99%) g i v i n g a r a t i o o f 2.4, w h i l e t h e m/e 301 p e a k (29.86%) shows l o w e r r e l a t i v e i n t e n s i t y t h a n t h e m/e 316 p e a k ( 8 4 . 6 6 % ) , g i v i n g a r a t i o o f 0.35. On t h e o t h e r h a n d , p a l u s t r i c a c i d g e n e r a t e s a l o w e r i n t e n s i t y o f t h e m/e 239 p e a k (36.80%) t h a n t h e m/e 241 p e a k (100%) w i t h a r a t i o o f 0.37; a n d t h e m/e 301 p e a k (88.55%) g r e a t e r t h a n t h e m/e 316 p e a k (64.54%) w i t h a r a t i o o f 1.37. The r a t i o s o f t h e r e l a t i v e i n t e n s i t i e s o f t h e m/e 239 p e a k a g a i n s t t h e m/e 241 p e a k , a n d t h e m/e 301 p e a k a g a i n s t t h e m/e 316 p e a k , a r e shown i n T a b l e 16. 110 Table 16. Ratios of the r e l a t i v e i n t e n s i t i e s of the m/e 239/241 and m/e 301/316 mass peaks of levopimaric and p a l u s t r i c acids on slash pine wood a f t e r 6 weeks of storage m/e ACIDS: 239/241 301/316 L e v o p i m a r i c 2.4 0.35 P a l u s t r i c 0.37 1.37 E x t r a c t a 0.37 1.37 a T h e s e v a l u e s c o r r e s p o n d t o t h e p e a k w h i c h was o b t a i n e d f o r ' t h e wood s a m p l e . C o m p a r i s o n o f t h e mass f r a g m e n t a t i o n p a t t e r n s o f p a l u s t r i c a c i d , l e v o p i m a r i c a c i d a n d t h e e x t r a c t r e v e a l s t h a t p a l u s t r i c a c i d i s t h e o n l y r e s i n a c i d p r e s e n t i n t h e m e t h a n o l i c e x t r a c t o f t h e wood s a m p l e a f t e r 6 weeks o f s t o r a g e (See A p p e n d i x A ) . W h i l e l e v o p i m a r i c a c i d c o u l d n o t be d e t e c t e d t h e p o s s i b i l i t y e x i s t s t h a t i t m i g h t h a v e b e e n p r e s e n t i n f r e s h wood, a n d t h a t i t m i g h t h a v e d i s a p p e a r e d d u r i n g s t o r a g e . T h i s s u p p o s i t i o n c a n be s u p p o r t e d b y I l l L a w r e n c e ' s s t u d y (1959) who f o u n d t h a t o x i d a t i o n o f r e s i n a c i d s i n t h e c h i p s was q u i t e r a p i d a n d t h a t i n a f e w h o u r s t h e c o n t e n t o f l e v o p i m a r i c a c i d was a p p r o x i m a t e l y o n e - h a l f o f t h a t o f t h e o r i g i n a l p i n e o l e o r e s i n . 4.4.1.2. Analysis of resin- and fatty acids in wood after 24 weeks of storage C h a r a c t e r i z a t i o n o f t h e r e s i n - a n d f a t t y a c i d s i n s l a s h p i n e wood a f t e r 24 weeks o f s t o r a g e was p e r f o r m e d i n a s i m i l a r f a s h i o n a s t h a t f o r wood a f t e r 6 weeks o f s t o r a g e . Gas c h r o m a t o g r a p h i c a n a l y s e s o f t h e r e s i n a c i d s w e r e p e r f o r m e d on t h e HP-5 f u s e d - s i l i c a c r o s s - l i n k e d b o n d e d - p h a s e d c a p i l l a r y c o l u m n , w h i l e t h e f a t t y a c i d s were a n a l y z e d on t h e n e w l y a c q u i r e d DB-225 megabore c a p i l l a r y c o l u m n . Q u a n t i t a t i v e r e s u l t s o f t h e r e s i n - a n d f a t t y a c i d s p r e s e n t i n t h e wood a f t e r a 24 weeks s t o r a g e a r e g i v e n i n T a b l e 17. The mass s p e c t r a l t o t a l i o n c h r o m a t o g r a m o f t h e m e t h y l a t e d wood e x t r a c t ( f r e e f a t t y a c i d s a n d r e s i n a c i d s ) a n d t h e s a p o n i f i e d - m e t h y l a t e d wood e x t r a c t ( t o t a l f a t t y a c i d s a n d r e s i n a c i d s ) a r e shown i n F i g . 16 a n d 17. I t c a n be s e e n f r o m t h e s e two c h r o m a t o g r a m s t h a t t h e p e a k a r e a s 112 Table 17. Fatty and r e s i n a c i d composition of slash pine wood a f t e r 24 weeks of storage (%) a Acids 5 3 Free Combined Total Fatty acids: P a l m i t i c 0.015 0.118 0.133 S t e a r i c 0.009 0.033 0.042 O l e i c ' 0.019 0.105 0.124 L i n o l e i c 0.005 0.010 0.015 L i n o l e n i c N.D. 0.002 0.002 TOTAL 0.048 0.268 0.316 Resin acids: P i m a r i c 0.028 S a n d a r a c o p i m a r i c 0.008 I s o p i m a r i c 0.050 P a l u s t r i c 0 . 037 D e h y d r o a b i e t i c 0.059 A b i e t i c 0. 017 N e o a b i e t i c 0 . 007 TOTAL 0.206 a= P e r c e n t a g e s a r e b a s e d on o v e n - d r i e d wood. b= A c i d s w e r e d e t e r m i n e d a s t h e i r m e t h y l e s t e r s . loo n RIC . CO 500 8:45 1000 17:30 1500 26:15 2000 SCAN 35:00 TIME Figure 16. Mass spectral t o t a l ion chromatogram of the free f a t t y and r e s i n acids (Methylated wood extract) Figure 17. Mass spectral t o t a l ion chromatogram of the t o t a l f a t t y and r e s i n acids (Saponified and methylated wood extract) 115 o f t h e f a t t y a c i d s i n c r e a s e c o n s i d e r a b l y a f t e r s a p o n i f i c a t i o n o f t h e f a t s p r e s e n t i n s l a s h p i n e wood. A c o m p a r i s o n o f t h e r e s i n - a n d f a t t y a c i d c o m p o s i t i o n s o f s l a s h p i n e wood a f t e r 6 a n d 24 weeks s t o r a g e i s g i v e n i n T a b l e 18. E x t r a c t s f o r b o t h s t o r a g e p e r i o d s g a v e s i m i l a r q u a l i t a t i v e r e s u l t s , b u t t h e a c i d q u a n t i t i e s were d i f f e r e n t . The p r o p o r t i o n o f f r e e f a t t y a c i d s (FFA) t o r e s i n a c i d s (RA) was g r e a t e r a f t e r 6 weeks s t o r a g e (FFA/RA= 0.33) t h a n a f t e r 24 weeks (FFA/RA= 0 . 2 3 ) . The amounts o f b o t h f r e e f a t t y a c i d s a n d r e s i n a c i d s were r e d u c e d s i g n i f i c a n t l y f r o m t h e f o r m e r v a l u e s t o a b o u t 1 4 . 1 % a n d 19.8%, r e s p e c t i v e l y . The c h a n g e i n r e s i n - a n d f a t t y a c i d c o n c e n t r a t i o n s were e a r l i e r e x p l a i n e d as t h e r e s u l t o f m e t a b o l i c a n d / o r d e g r a d a t i v e r e a c t i o n s o f f a t t y a n d r e s i n a c i d s i n s e a s o n e d wood ( A s s a r s s o n a n d A k e r l u n d , 1 9 6 7 ) . G r e a t e r r e d u c t i o n o f f a t t y a c i d s m i g h t be t h e r e s u l t o f a d d i t i o n a l a u t o x i d a t i o n r e a c t i o n s o f f r e e f a t t y a c i d s , e s p e c i a l l y t h o s e o f o l e i c , l i n o l e i c a n d l i n o l e n i c a c i d s ( L a w r e n c e , 1959; M i y a s h i t a a n d T a k a g i , 1 9 8 6 ) . I t was f o u n d i n t h i s s t u d y t h a t w i t h i n t h e 6 t o 24 weeks, a l m o s t 5 0 % o f t h e e s t e r i f i e d f a t t y a c i d s a r e h y d r o l y z e d a nd p r o b a b l y m e t a b o l i z e d by m i c r o b i a l r e s p i r a t i o n t o c a r b o n d i o x i d e a n d w a t e r . Table 18. Resin and fa t t y acid composition of slash pine wood a f t e r 6 and 24 weeks storage (%) Storage time (Weeks) 6 24 F r e e C o m b i n e d T o t a l F r e e C o m b i n e d T o t a l Fatty Acids: 0 . 3 4 0 1 .040 1 .380 0 . 0 4 8 0 . 2 6 8 0 . 3 1 6 Resin Acids 1 .040 — — _ 1 .040 0 . 2 0 6 — — — 0 . 2 0 6 A A 1 1 v a l u e s a r e p e r c e n t a g e s on O . D . wood b a s i s . 117 4.4.1.3. Analysis of r e s i n acids i n wood a f t e r 52 weeks of storage R e s i n a c i d s w e re c h a r a c t e r i z e d i n wood s a m p l e s a f t e r 52 weeks o f s t o r a g e . The r e s i n a c i d c o m p o s i t i o n a f t e r t h i s p e r i o d o f s t o r a g e shows c o n s i d e r a b l e c h a n g e f r o m t h a t d e t e r m i n e d a f t e r 6 a n d 24 weeks s t o r a g e . I t was f o u n d t h a t t h e r e l a t i v e p r o p o r t i o n o f t h e s e r e s i n a c i d s may d e c r e a s e , i n c r e a s e o r m a n t a i n a l m o s t t h e same v a l u e s . On one h a n d , p a l u s t r i c a c i d i s r e d u c e d f r o m 33.7 t o 2.5%, a b i e t i c a c i d f r o m 13.1 t o 1.6%, a n d n e o a b i e t i c a c i d f r o m 8.4 t o 1.2%. On t h e o t h e r h a n d , i n c r e a s e s f o r s a n d a r a c o p i m a r i c f r o m 3.9 t o 15.6%, a n d d e h y d r o a b i e t i c f r o m 7.6 t o 4 8 . 5 % were o b s e r v e d , w h i l e p i m a r i c a n d i s o p i m a r i c a c i d s showed l i t t l e c h a n g e . The r e l a t i v e p r o p o r t i o n s o f r e s i n a c i d s i n s l a s h p i n e wood a f t e r 6 , 24 a n d 52 weeks s t o r a g e a r e g i v e n i n T a b l e 19 a n d F i g . 18. Table 19. Relative proportion (%) of r e s i n acids i n slash pine wood a f t e r 6, 24 and 52 weeks storage S t o r a g e t i m e (weeks) Resin Acids: 6 24 52 P i m a r i c 10.7 13.6 11.7 S a n d a r a c o p i m a r i c 3.9 3.9 15. 6 I s o p i m a r i c 22. 6 24.3 18.9 P a l u s t r i c 33.7 18.0 2.5 D e h y d r o a b i e t i c 7.6 28.6 48.5 A b i e t i c 13.1 8.3 1.6 N e o a b i e t i c 8.4 3.4 1.2 TOTAL 100.0 100.0 100.0 ^ P e r c e n t a g e s a r e b a s e d o n l y on t h e t o t a l amount o f t h e s e v e n r e s i n a c i d s c h a r a c t e r i z e d i n t h i s s t u d y . 118 50-| 0 6 24 52 Weeks F i g u r e 1 8 . R e l a t i v e p r o p o r t i o n o f r e s i n a c i d s i n s l a s h p i n e wood a f t e r 6, 24 and 52 weeks o f s t o r a g e 119 V a r i a t i o n s i n t h e r e l a t i v e p r o p o r t i o n s o f t h e s e a c i d s may be due t o i s o m e r i z a t i o n a n d / o r a u t o d e g r a d a t i o n , a n d / o r o x i d a t i o n r e a c t i o n s . The e x a c t m e c h a n i s m s b y w h i c h t h e s e r e s i n a c i d s a r e c o n v e r t e d i n t o p r o d u c t s i s u n c l e a r . M o s t r e s i n a c i d s f o u n d i n p i n e s p e c i e s h a v e s t r u c t u r e s w h i c h c o u l d b e r e a d i l y c o n v e r t e d t o d e h y d r o a b i e t i c b y s i m p l e m e c h a n i s t i c p r o c e s s e s s u c h a s i s o m e r i z a t i o n a n d d e h y d r o g e n a t i o n , b u t how t h i s o c c u r s i s n o t f u l l y u n d e r s t o o d . B a c t e r i a l p o p u l a t i o n s , e x i s t i n g i n wood, may h a v e a r o l e . 4.5. Organosolv Pulping of Slash Pine I n t h e l a s t d e c a d e , a l o t o f e f f o r t a n d money h a s b e e n p u t i n t o r e s e a r c h a n d d e v e l o p m e n t on o r g a n o s o l v p u l p i n g l e a d i n g t o a b e t t e r u n d e r s t a n d i n g o f i t s c h e m i s t r y a n d t o o v e r c o m e most o f i t s d r a w b a c k s . F o r e x a m p l e , t h e A L C E L L company h a s s p e n t up t o $5 m i l l i o n t o d e v e l o p i t s s o l v e n t p u l p i n g p r o c e s s , w h i l e ORGANOCELL r e p o r t e d a c o s t o f 45 m i l l i o n DM ($32.5 m i l l i o n CDN) t o a c h e i v e a p r o d u c t i o n o f 5 T /day ( P a p p e n s , 1990; D a hlmann a n d S c h r o e t e r , 1 9 9 0 ) . Some p r o c e s s d i s a d v a n t a g e s r e l a t e t o t h e d i f f i c u l t y o f p u l p i n g m i x e d wood s p e c i e s , t h e e x t r e m e l y e f f i c i e n t c o n t r o l n e e d e d t o h a n d l e t h e v o l a t i l e p u l p i n g 120 c h e m i c a l s , a n d t h e p r o p e r p u l p w a s h i n g p r o c e d u r e t o a v o i d r e p r e c i p i t a t i o n o f l i g n i n o n t o t h e p u l p f i b e r s . I t seems t h a t d u r i n g o r g a n o s o l v p u l p i n g , most o f t h e e x t r a c t i v e s a r e r e m o v e d f r o m t h e wood, b a s e d on t h e i r s o l u b i l i t y c h a r a c t e r i s t i c s i n m e t h a n o l . I n a d d i t i o n t o t h i s a s s u m p t i o n , due t o t h e s h o r t p u l p i n g p e r i o d s ( i . e . 15 t o 60 min) i t c a n be e x p e c t e d t h a t t h e e x t r a c t i v e s may s u f f e r o n l y m i l d c h a n g e s t o t h e i r c h e m i c a l s t r u c t u r e s . A l t h o u g h , s i d e r e a c t i o n s m i g h t o c c u r ( i . e . f r a g m e n t a t i o n , i s o m e r i z a t i o n , c o n d e n s a t i o n a n d / o r o x i d a t i o n ) a n d t h e e x t e n t o f t h e s e o r g a n i c r e a c t i o n s m i g h t be l e s s p r o n o u n c e d t h a n t h o s e f o u n d d u r i n g t h e a c t u a l c o m m e r c i a l c h e m i c a l p u l p i n g p r o c e s s e s , i . e . , s u l f i t e o r k r a f t p r o c e s s e s . I t was a l s o e x p e c t e d t h a t t h e e x t r a c t i v e s a f t e r p u l p i n g m i g h t be e i t h e r d i s s o l v e d i n t h e b l a c k l i q u o r ( m e t h a n o l - w a t e r p h a s e ) , a d s o r b e d o n t o t h e l i g n i n w h i c h p r e c i p i t e s on c o o l i n g o u t o f t h e b l a c k l i q u o r , o r e n t r a p p e d i n t h e r e s u l t i n g p u l p . T h e r e f o r e , i t was n e c e s s a r y t o i s o l a t e , c o n c e n t r a t e a n d c h a r a c t e r i z e t h e r e s i n - a n d f a t t y a c i d s f r o m t h e f r a c t i o n s m e n t i o n e d a b o v e . As t h e m a i n o b j e c t i v e o f t h i s work, i t was i m p o r t a n t t o c h a r a c t e r i z e t h e r e s i n - a n d f a t t y a c i d s i n t h e wood b e f o r e a n d a f t e r p u l p i n g . F u r t h e r m o r e , due t o t h e d r a s t i c s t r u c t u r a l ( c h e m i c a l ) a n d / o r c o n t e n t v a r i a t i o n s o f t h e s e a c i d s i n t h e g r e e n s t a t e , a s c o m p a r e d t o t h e c o m p o s i t i o n f o l l o w i n g 20 o r 24 weeks o f s t o r a g e ( A s s a r s s o n , 1967) 121 ( s e c t i o n 4 . 4 . 1 ) , a l l p u l p i n g e x p e r i m e n t s w e re p e r f o r m e d on wood s t o r e d f o r 24 weeks i n o r d e r t o a v o i d c h a n g e s u n r e l a t e d t o p u l p i n g a n d t o m i n i m i z e t h e r i s k o f m i s i n t e r p r e t a t i o n o f t h e p u l p i n g r e s u l t s when u s i n g f r e s h wood. 4.5.1. Resin- and f a t t y acids analysis a f t e r pulping T h e r e i s a l a r g e b o d y o f i n f o r m a t i o n a v a i l a b l e on how l i g n i n a n d c e l l u l o s e a r e d e g r a d e d d u r i n g t h e c o u r s e o f t h e c h e m i c a l p u l p i n g p r o c e s s e s ( C l a y t o n , 1 969; G e l l e r s t e d t a n d L i n d f o r s , 1984; M a c L e o d e t al., 1984; B u c h w a l t e r , 1 9 8 5 ; O h i a n d I s h i z u , 1989) . Some o f t h e s e s t u d i e s w e r e a l s o e x t e n d e d t o o r g a n o s o l v p u l p i n g ( G a r v e s , 1988; P a s z n e r a n d Cho, 1989) . However, a l m o s t no e f f o r t s h a v e b e e n made t o s t u d y t h e c h a n g e s w h i c h e x t r a c t i v e s may s u f f e r d u r i n g h i g h t e m p e r a t u r e o r g a n o s o l v p u l p i n g . J u d g i n g f r o m t h e l o w e x t r a c t i v e c o n t e n t o f o r g a n o s o l v p u l p s ( B e h e r a , 1985) b o t h t h e e x t r a c t i v e s a n d l i g n i n a r e d i s s o l v e d i n t h e b l a c k l i q u o r ( m e t h a n o l - w a t e r a t 80:20 r a t i o ) . T h e r e f o r e , i t was n e c e s s a r y t o remove s e l e c t i v e l y t h e r e s i n - a n d f a t t y a c i d s ( e x t r a c t i v e s i n g e n e r a l ) f r o m t h e b l a c k l i q u o r b y u s i n g a t h i r d s o l v e n t l e a v i n g t h e l i g n i n a n d s u g a r s i n s o l u t i o n . The r e s i n - a n d f a t t y a c i d s w e r e i s o l a t e d b y u s i n g l i q u i d - l i q u i d e x t r a c t i o n . S e v e r a l 122 s o l v e n t s ( p e t r o l e u m e t h e r , c h l o r o f o r m , a n d d i e t h y l e t h e r ) w e r e s t u d i e d as p o s s i b l e s o l v e n t s w i t h s u f f i c i e n t s e l e c t i v i t y i n o r d e r t o a c c o m p l i s h t h e s e g o a l s b y s i m p l e l i q u i d - l i q u i d e x t r a c t i o n . Due t o i t s g o o d d i s s o l v i n g p o w e r o f t h e e x t r a c t i v e s a n d t h e p o o r s o l u b i l i t y o f t h e l i g n i n , d i e t h y l e t h e r was s e l e c t e d as t h e b e s t s o l v e n t t o p e r f o r m s u c h e x t r a c t i o n s . I t i s known t h a t e t h e r i s s l i g h t l y s o l u b l e i n w a t e r a n d vice versa. A s a t u r a t e d w a t e r s o l u t i o n c o n t a i n s 8.43% (w/w) o f e t h e r a t 1 5 2 C a n d 6.05% (w/w) a t 2 5 2 C . E t h e r s a t u r a t e d w i t h w a t e r c o n t a i n s 1.2% a t 2 0 a C . E t h e r i s m i s c i b l e w i t h l o w e r a l i p h a t i c a l c o h o l s , b e n z e n e , c h l o r o f o r m , p e t r o l e u m e t h e r , o t h e r f a t s o l v e n t s , a n d many o i l s ( A n o n . , 1 9 8 3 ) . T a b l e 20 shows t h e number o f mL o f t h e i n i t i a l w a t e r -m e t h a n o l m i x t u r e , t h e m i n i m a l v o l u m e s o f d i e t h y l e t h e r n e e d e d t o p r o v o k e p h a s e s e p a r a t i o n a n d t h e r a t i o o f t h e p e r c e n t a g e s o f t h e r e s u l t i n g m i x t u r e s E t 2 0 / M e O H , E t 2 0 / H 2 0 a n d t h e s t a r t i n g I ^ O / M e O H m i x t u r e . P l o t t i n g o f t h i s d a t a i s d e p i c t e d i n t h e p h a s e d i a g r a m s p r e s e n t e d i n F i g . 19 a n d 2 0 . A more p r a c t i c a l p h a s e d i a g r a m t o u s e i s t h e x a n d y r e l a t i o n s h i p d e p i c t e d i n F i g . 1 9 . By p l o t t i n g t h e w a t e r - m e t h a n o l p r o p o r t i o n s on t h e " X " a x i s ( b l a c k l i q u o r c o m p o s i t i o n ) a n d t h e number o f mL o f d i e t h y l e t h e r n e e d e d f o r p h a s e s e p a r a t i o n Table 20 . Data fo r the phase diagram separat ion o f the t e r t i a r y solvent mixture methanol-water-diethyl ether Mixture * Solvent (mL) Ratio H 20 Me OH E t 2 0 H20/MeOH Et20/H20 Et 20/MeOH 1 9, .0 1. .0 1.0 9. .00 0, .11 1. .00 2 8. .5 1. .5 1.3 5, .70 0, .15 0. .87 3 8, .0 2. .0 1.6 4, .00 0. .19 0. .85 4 7. .0 3. .0 2.1 2. .33 0. .30 0. .70 5 6, .0 4. .0 2.5 1. .50 0, .42 0. .63 6 5. .7 4. .3 3.4 1. .33 0, .60 0. .80 7 5. .5 4. .5 4.2 1. .22 0. .76 0. .93 8 5. .2 4. .8 5.2 1. .10 1, .00 1. .10 9 5, .0 5. .0 6.0 1, .00 1, .20 1. .20 10 4, .8 5. .2 7.0 0. .92 1. .46 1. .35 11 4. .6 5. .4 9.0 0, .85 1. .96 1. .67 12 4. .5 5. .5 10.4 0, .82 2. .31 1. .90 13 4, .3 5. .7 13.5 0. .75 3, .14 2. .37 14 4, .0 6. .0 17.0 0. .67 4. .25 2. .83 15 3, .8 6. .2 21.0 0. .61 5. .53 3. .39 16 3. .0 7. .0 * 0. .43 * * * At H20/MeOH r a t i o lower than 0.45 there i s no phase separation. J I I I I 2 4 6 8 10 Hater/MeOH Ratio Figure 19. Phase diagram of the ternary solvent mixture methanol-water-diethyl ether: X and Y relationship Ether (100%) Water Me OH Figure 20. Phase diagram of the ternary solvent mixture methanol-water-diethyl ether: Triangular relationship 126 on t h e "Y" a x i s , t h e n b y u s i n g t h i s c h a r t , s t a r t i n g w i t h any b l a c k l i q u o r c o m p o s i t i o n ( w a t e r - m e t h a n o l r a t i o ) , i t i s p o s s i b l e t o f i n d t h e p r o p e r amount o f e x t r a c t i n g o r g a n i c s o l v e n t ( d i e t h y l e t h e r ) w h i c h w o u l d g i v e t h e r i g h t p r o p o r t i o n s f o r s e l e c t i v e p h a s e s e p a r a t i o n . A c c o r d i n g l y , F i g . 19 becomes a p r a c t i c a l c h a r t t o u s e i n s o l v e n t p u r i f i c a t i o n o f t h e b l a c k l i q u o r o f an o r g a n o s o l v p u l p m i l l . A t t e m p t s t o d e r i v e an e q u a t i o n t h a t w o u l d r e p r e s e n t t h e c u r v e p r e s e n t e d i n t h e t r i a n g l e o f F i g . 20 a n d t h u s f a c i l i t a t e t h e c a l c u l a t i o n o f t h e p r o p o r t i o n s seems t o be q u i t e c o m p l e x a n d e x a m p l e s f o r s u c h e x e r c i s e s were n o t f o u n d i n t h e l i t e r a t u r e . However, f o r t h e l e s s c o m p l e x c u r v e i n F i g . 19 an e q u a t i o n f o r t h e r e l a t i o n s h i p o f t h e x an d y p a r a m e t e r s i s p r e s e n t e d b e l o w : Y = 5.248 - 0.355 CX) - 11.948 (1/X) + 13.328 U/X) 2 SOURCE SUM-OF-SQUARES DF MEAN-SQUARE REGRESSION RESIDUAL 1,256.895 1.665 4 11 -314.224 0.151 TOTAL CORRECTED 1,258.560 520.757 15 14 RAW R-SQUARED (1-RESIDUAL/TOTAL) CORRECTED R-SQUARED (1-RESIDUAL/CORRECTED 0.999 0.997 127 From both of these phase diagrams ( F i g . 19 and 20) i t can be seen t h a t when working with equal volumes of and MeOH ( r a t i o of 1.0, 5 mL of water - 5 mL of methanol), the minimal amount of d i e t h y l e t h e r (6 mL) needed f o r phase s e p a r a t i o n i s h i g h e r than i n d i c a t e d by the i n i t i a l volumes of water and methanol. However, i f the i n i t i a l amount of methanol i s reduced ( i . e . at ^O/MeOH of a r a t i o of 4.0, 8 mL of water and 2 mL of methanol) then the amount of Et20 needed decreases t o 1.6 mL, and hence the number of e x t r a c t i o n s must be i n c r e a s e d i f the same e x t r a c t i o n e f f i c i e n c y i s t o be obt a i n e d . Furthermore, at t h i s r a t i o , because of the h i g h e r amount of water, p r e c i p i t a t i o n of l i g n i n i s more l i k e l y t o happen, a c o n d i t i o n c l e a r l y u n d e s i r a b l e f o r such a system t o f u n c t i o n e f f i c i e n t l y . On the other hand, i f the amount of methanol i s i n c r e a s e d (^O/MeOH r a t i o 0.82, i . e . water 4.5 mL and methanol 5.5 mL) , then phase s e p a r a t i o n of the b l a c k l i q u o r t akes p l a c e g i v i n g water c o n t a i n i n g the d i s s o l v e d sugars i n s o l u t i o n as one phase, and an e t h e r e a l Et20/Me0H phase with the l i g n i n and e x t r a c t i v e s due t o the hig h s o l u b i l i t y of the et h e r i n methanol and low s o l u b i l i t y i n water. The r e f o r e , i f s o l v e n t e x t r a c t i o n s of the organosolv b l a c k l i q u o r are t o be performed f o r removal of e x t r a c t i v e s , l i g n i n or sugars, then i t i s necessary t o 128 know w h i c h one o f t h e s e e n t i t i e s h a s t o b e r e m o v e d o r e x t r a c t e d , a n d a c o m p r o m i s e o f f a c t o r s must b e a c c e p t e d s u c h a s : a. ) The t i m e o r e f f o r t r e q u i r e d t o remove t h e e x t r a c t i v e s b y s o l v e n t e x t r a c t i o n . I n g o i n g f r o m a H 20/MeOH= 1.0 t o a h i g h e r r a t i o ( i . e . H 20/MeOH= 4 . 0 ) , l e s s e t h e r i s n e e d e d f o r p h a s e s e p a r a t i o n , b u t t h e number o f e x t r a c t i o n s must be i n c r e a s e d t o o b t a i n c o m p l e t e a n d s e l e c t i v e r e m o v a l o f t h e e x t r a c t i v e s . b. ) The p r o p e r p r o p o r t i o n s o f t h e s o l v e n t s i n o r d e r t o g e t t h e c o r r e c t p h a s e s e p a r a t i o n . I n t h i s c a s e , t h e e t h e r h a d t o be s e p a r a t e d f r o m t h e w a t e r - m e t h a n o l m i x t u r e i n o r d e r t o s e l e c t i v e l y remove t h e e x t r a c t i v e s f r o m t h e c o o k i n g l i q u o r , a n d t o a v o i d p r e c i p i t a t i o n o f t h e l i g n i n . b . l . A t H 20/MeOH r a t i o l o w e r t h a n 0.82 ( i . e . H 20/MeOH r a t i o o f 0.67, w a t e r = 4.0 mL a n d m e t h a n o l = 6.0 mL) t h e m i n i m a l amount o f E t 2 0 n e e d e d f o r p h a s e s e p a r a t i o n i s q u i t e l a r g e ( E t 2 0 = 17 mL). B e c a u s e o f t h e h i g h s o l u b i l i t y o f t h e m e t h a n o l i n e t h e r , t h e w a t e r s e p a r a t e s f r o m t h e E t 2 0 - m e t h a n o l m i x t u r e . T h e r e f o r e , i t i s v e r y l i k e l y t h a t l i g n i n a n d e x t r a c t i v e s w i l l be f o u n d i n t h e e t h e r - m e t h a n o l p h a s e , w h i l e t h e s u g a r s must be i n s o l u t i o n i n t h e w a t e r p h a s e . T h i s a p p r o a c h w o u l d be s u i t a b l e i f e x t r a c t i v e s - a n d l i g n i n - f r e e 129 s u g a r s w e re t o be o b t a i n e d , l e a v i n g t h e m i x t u r e o f e x t r a c t i v e s a n d l i g n i n i n t h e o r g a n i c p h a s e . b . 2 . I f t h e l i g n i n r e m o v a l i s p e r f o r m e d a f t e r r e m o v a l o f t h e e x t r a c t i v e s f r o m t h e b l a c k l i q u o r , a s s t a t e d a b o v e , t h e n i t i s f e a s i b l e t o o b t a i n e x t r a c t i v e - f r e e f e r m e n t a b l e s u g a r s i n t h e w a t e r w h e r e a s t h e l i g n i n i s s e p a r a t e d i n t h e E t 2 0 / m e t h a n o l p h a s e . b . 3 . A t H 20/MeOH r a t i o h i g h e r t h a n 1.5 ( i . e . H 20/MeOH r a t i o o f 4.0, w a t e r = 8 mL a n d m e t h a n o l = 2 mL) t h e amount o f E t 2 0 n e e d e d f o r p h a s e s e p a r a t i o n i s 1.6 mL. U n d e r t h e s e c o n d i t i o n s , t h e r e i s e n o u g h w a t e r ( t o p r o m o t e s e p a r a t i o n f r o m t h e e t h e r ) b u t i n s u f f i c i e n t m e t h a n o l t o k e e p t h e l i g n i n i n s o l u t i o n . T h e r e f o r e , f o r e f f i c i e n t e x t r a c t i v e s r e m o v a l , a g r e a t number o f e t h e r ( o n l y 1.6 mL) e x t r a c t i o n s a r e n e e d e d a n d t h e l o w m e t h a n o l c o n t e n t a n d h i g h w a t e r c o n t e n t w i l l p r o m o t e p r e c i p i t a t i o n o f t h e l i g n i n . A s h o r t i n v e s t i g a t i o n on t h e e f f i c i e n c y o f t h e r e c o v e r y was c o n d u c t e d i n o r d e r t o e s t i m a t e t h e m a r g i n o f e r r o r f o r t h i s p r o c e d u r e . N e a r l y 1 0 0 % o f t h e r e s i n - a n d f a t t y a c i d s w e re q u a n t i t a t i v e l y r e c o v e r e d when p e r f o r m i n g t h e e x t r a c t i o n s a t t h e w a t e r - m e t h a n o l - e t h e r (50:40:50) r a t i o o r t h e e q u i v a l e n t w a t e r : m e t h a n o l = 1.25 (50:40) r a t i o . E x t r a c t i v e s r e c o v e r i e s o f no l e s s t h a n 9 5 - 9 6 % a r e o b t a i n e d when t h e w a t e r - m e t h a n o l r a t i o s go c l o s e r t o 1.0 (50:50) o r 1.375 ( 5 5 : 4 0 ) . 130 I t c a n be c o n c l u d e d t h a t r e m o v a l o f t h e e x t r a c t i v e s b y l i q u i d - l i q u i d e x t r a c t i o n o f a w a t e r - m e t h a n o l m i x t u r e w i t h d i e t h y l e t h e r must be p e r f o r m e d w i t h i n t h e w a t e r -m e t h a n o l r a n g e b e t w e e n 1.0 t o 1.4. W i t h i n t h i s r a n g e t h e i d e a l w a t e r - m e t h a n o l r a t i o f o r t h e b e s t e x t r a c t i o n e f f i c i e n c y i s 1.25. 4.5.1.1. Resin- and f a t t y acids analysis a f t e r 5 min pulping Due t o t h e u s e o f m e t h a n o l (an e x c e l l e n t o r g a n i c s o l v e n t w i t h h i g h d i s s o l v i n g p o w e r f o r e x t r a c t i v e s ) a t h i g h t e m p e r a t u r e a n d h i g h p r e s s u r e , i t was e x p e c t e d t h a t m ost o f t h e e x t r a c t i v e s w o u l d be r e m o v e d a t e a r l y s t a g e s o f t h e p u l p i n g p r o c e s s . A 5 m i n p u l p i n g t i m e was c h o s e n as t h e s h o r t e s t t i m e s i n c e t h e e s t i m a t e d r a t e o f h e a t i n g o f t h e s t a i n l e s s s t e e l v e s s e l was a b o u t 2 6 2 C / m i n . E x t r a c t i v e s r e m o v a l was s t u d i e d o n l y f o r t h e i n d u s t r i a l l y r e l e v a n t t e m p e r a t u r e o f 2 0 5 2 C . D e l i g n i f i c a t i o n o f s o f t w o o d s i s l a r g e l y i n c o m p l e t e a t t e m p e r a t u r e u n d e r 2 0 0 S C a n d p r o l o n g e d c o o k i n g l e a d s t o a r a p i d l o s s o f c e l l u l o s e v i s c o s i t y a n d p o o r p u l p ( P a s z n e r a n d C h a n g , 1 9 8 3 ) . I n t h e 5 m i n c o o k s , c h a r a c t e r i z a t i o n o f t h e e x t r a c t i v e s was p e r f o r m e d o n l y on t h o s e p r e s e n t i n t h e b l a c k l i q u o r s i n c e no d e f i b e r i z a t i o n ( f i b e r l i b e r a t i o n ) o c c u r s on s u c h s h o r t c o o k i n g . Q u a n t i t a t i v e v a l u e s f o r t h e 131 r e s i n - a n d f a t t y a c i d s f o l l o w i n g 5 m i n c o o k i n g a r e g i v e n i n T a b l e 2 1 . T h e s e r e s u l t s show t h a t e v e n a f t e r s u c h s h o r t c o o k i n g , a b o u t 90% o f t h e r e s i n a c i d s a n d 2 5 % o f t h e f a t t y a c i d s w e r e f o u n d i n t h e c o o k i n g l i q u o r a n d a p p a r e n t l y s u r v i v e d t h e h i g h t e m p e r a t u r e e x t r a c t i o n . The d i f f e r e n c e s i n d e g r e e o f r e m o v a l o f t h e two t y p e s o f a c i d s a r e d i f f i c u l t t o e x p l a i n . However, i t i s p o s s i b l e t o r a t i o n a l i z e t h a t t h e i r d i f f e r e n t s o l u b i l i t y i n m e t h a n o l a n d / o r t h e i r d i f f e r e n t l o c a t i o n i n t h e wood, may be r e s p o n s i b l e f o r t h e d i f f e r e n c e s i n s o l u b i l i t y / r e m o v a l by h o t m e t h a n o l . T o t a l f a t t y a c i d s r e p r e s e n t t h e f r e e f a t t y a c i d s o r i g i n a l l y p r e s e n t i n wood (0.048%) p l u s a f r a c t i o n o f f a t t y a c i d s r e s u l t i n g f r o m f a t s , w h i c h must h a v e b e e n h y d r o l y z e d d u r i n g t h e p u l p i n g p r o c e s s . The p e r c e n t a g e o f s a t u r a t e d f a t t y a c i d s f o u n d i n t h e b l a c k l i q u o r i s l o w e r t h a n t h a t d e t e r m i n e d i n t h e wood as f r e e a c i d s . T h e r e f o r e , i t seems t h a t s a t u r a t e d f a t t y a c i d s a r e l e s s s o l u b l e i n h o t m e t h a n o l a n d more d i f f i c u l t t o remove t h a n u n s a t u r a t e d o n e s ( P a l m i t i c = 0.009% a n d S t e a r i c = 0 . 0 0 2 % ) . On t h e o t h e r h a n d , o l e i c a n d l i n o l e i c a c i d s w e r e r e m o v e d i n h i g h e r a mounts ( 0 . 0 4 7 % a n d 0.022%) due t o t h e h y d r o l y s i s o f f a t s p r e s e n t i n t h e wood. 132 Table 21. Resin- and f a t t y a c i d composition i n slash pine wood and black l i q u o r a f t e r 5 minutes of organosolv p u l p i n g a Wood Black Liquor Fatty Acids: Free Total Free P a l m i t i c 0.015 0.133 0.009 S t e a r i c 0.009 0.042 0.002 O l e i c 0.019 0.124 0.047 L i n o l e i c 0.005 0.015 0.022 L i n o l e n i c N.D.b 0.002 0.001 TOTAL 0.048 0.316 0.081 Resin Acids: P i m a r i c 0.028 0.029 Sandaracopimaric 0.008 0.009 I s o p i m a r i c 0.050 0.051 P a l u s t r i c 0.037 0.005 D e h y d r o a b i e t i c 0.059 0.051 A b i e t i c 0.017 0.038 N e o a b i e t i c 0.007 0.002 TOTAL 0.206 0.185 a A l l v a l u e s are percentages on O.D. wood b a s i s . b N.D.= Not de t e c t e d . 133 Among t h e r e s i n a c i d s i t seems t h a t t h o s e o f t h e p i m a r a n e ( p i m a r i c ) a n d i s o p i m a r a n e ( i s o p i m a r i c a n d s a n d a r a c o p i m a r i c ) t y p e a r e a l m o s t c o m p l e t e l y r e m o v e d f r o m wood a n d t h e i r c h e m i c a l s t r u c t u r e r e m a i n s u n c h a n g e d on o r g a n o s o l v p u l p i n g . However, w i t h t h e e x c e p t i o n o f a b i e t i c a c i d , r e s i n a c i d s o f t h e a b i e t a n e t y p e ( p a l u s t r i c , d e h y d r o a b i e t i c a n d n e o a b i e t i c ) w e re f o u n d i n l o w e r amounts i n t h e c o o k i n g l i q u o r t h a n t h o s e o r i g i n a l l y p r e s e n t i n wood. I t seems t h a t a p o r t i o n o f p a l u s t r i c a n d n e o a b i e t i c a c i d i s o m e r i z e s i n t o a more " t h e r m o s t a b l e " f o r m l i k e a b i e t i c a c i d . The r e d u c t i o n o f d e h y d r o a b i e t i c a c i d c a n be e x p l a i n e d i n t e r m s o f i n c o m p l e t e r e m o v a l b y t h e m e t h a n o l f r o m t h e wood. S i n c e r e s i n - a n d f a t t y a c i d s c a n be e a s i l y r e m o v e d e v e n a f t e r s h o r t p u l p i n g p e r i o d s (5 m i n ) , i t m i g h t be i n f e r r e d t h a t s h o r t c o o k s o f t h i s t y p e c a n be u s e d a s p r e -t r e a t m e n t s ( f o r e x t r a c t i v e r e m o v a l ) w h e n e v e r a h i g h e x t r a c t i v e c o n t e n t wood m i g h t be a p r o b l e m ( i . e . i n p r e p a r i n g d i s s o l v i n g p u l p s ) . 134 4.5.1.2. Resin- and f a t t y acids analysis a f t e r 20 min pulping Quantitative r e s u l t s of the r e s i n - and f a t t y acids a f t e r 20 min pulping are shown i n Table 2 2 . This table reveals that a f t e r 20 min of organosolv pulping about 60% of the t o t a l f a t t y acids were removed* from the wood. Most of these f a t t y acids were found i n the black liquor ( 4 4 . 0 % ) . Almost equal amounts of extractives were d i s t r i b u t e d between the p r e c i p i t a t e d l i g n i n (Lignin I) and the pulp at 1 6 . 5 % and 1 5 . 5 % , respectively. A comparison between the t o t a l f a t t y acids af t e r pulping (fatty acids i n the black liquor, l i g n i n and pulp) with those found i n the wood before pulping (free and t o t a l f a t t y acids), i s as follows: Total saturated f a t t y acids found aft e r pulping -palmitic (0.055%) and s t e a r i c ( 0 . 0 2 3 % ) - are present i n lower percentages than those found i n wood -palmitic (0.133%) and s t e a r i c ( 0 . 0 4 2 % ) . The amount of unsaturated f a t t y acids a f t e r pulping i s equal to that found i n wood with respect to o l e i c and l i n o l e n i c acid, but higher for l i n o l e i c acid. However, o l e i c acid remains the predominant fa t t y acid component of fats in slash pine wood. * Removed extractives are either dissolved i n the black liq u o r or adsorbed onto the p r e c i p i t a t e d l i g n i n ("Lignin I " ) . The rest of the extractives remain i n the pulp. Table 22. Resin-and f a t t y acid composition i n slash pine wood a f t e r 20 min of organosolv p u l p i n g 3 Wood Fatty Acids: Free Total P a l m i t i c 0. 015 0 .133 S t e a r i c 0. 009 0 .042 O l e i c 0. 019 0 .124 L i n o l e i c 0. 005 0 .015 L i n o l e n i c N .D. 0 .002 TOTAL 0. 048 0 .316 Resin acids: P i m a r i c 0. 028 S a n d a r a c o p i m a r i c 0. 008 I s o p i m a r i c 0. 050 P a l u s t r i c 0. 037 D e h y d r o a b i e t i c 0. 059 A b i e t i c 0. 017 N e o a b i e t i c 0. 007 TOTAL 0. 206 Black Precip Pulp Liquor Lignin Total Total Total TOTAL 0.028 0.007 0.020 0.055 0.004 0.002 0.017 0.023 0.078 0.034 0.011 0.123 0.028 0.008 0.001 0.037 0.001 0.001 0.002 0.139 0.052 0.049 0.240 0.024 0.005 0.029 0.006 0.002 • • • 0.008 0.035 0.008 • • • 0.043 0.010 0.001 • • • 0.011 0.035 0.004 0.031 0.070 0.022 0.006 0.012 0.040 0.001 0.001 0.002 0.134 0.027 0.043 0.203 3 A l l v a l u e s a r e p e r c e n t a g e s on O.D. wood b a s i s . 136 Summation o f t h e p e r c e n t a g e s o f t h e f a t t y a c i d s f o u n d a f t e r p u l p i n g ( b l a c k l i q u o r + p r e c i p i t a t e d l i g n i n + p u l p ) a c c o u n t s f o r o n l y 76% o f t h e o r i g i n a l t o t a l f a t t y a c i d s p r e s e n t i n wood. An e x p l a n a t i o n o f t h i s g ap m i g h t be a t t r i b u t e d t o an i n c o m p l e t e h y d r o l y s i s o f t h e e s t e r i f i e d f a t t y a c i d s ( f a t s ) d u r i n g t h i s s h o r t c o o k i n g p e r i o d . The t o t a l amount o f r e s i n a c i d s r e m o v e d f r o m t h e wood a f t e r 20 m i n p u l p i n g was a b o u t 78.8% o f t h e t o t a l r e s i n a c i d s p r e s e n t i n t h e wood. M o s t o f t h e r e s i n a c i d s w e r e f o u n d i n t h e b l a c k l i q u o r (65.5 %) , a n d t h e r e s t i n t h e p r e c i p i t a t e d l i g n i n (13.3%) a n d t h e p u l p (21.2%). D e h y d r o a b i e t i c a n d a b i e t i c a c i d s w e r e t h e o n l y d e t e c t a b l e r e s i n a c i d s p r e s e n t i n t h e p u l p . The r e s i n a c i d s o f t h e p i m a r a n e a n d i s o p i m a r a n e ( p i m a r i c , i s o p i m a r i c a n d s a n d a r a c o p i m a r i c a c i d s ) t y p e were d e t e c t e d i n t h e b l a c k l i q u o r a n d p r e c i p i t a t e d l i g n i n . T h e i r t o t a l p e r c e n t a g e s w e re v e r y c l o s e t o t h e on e s f o u n d i n t h e wood b e f o r e p u l p i n g . W i t h i n t h e r e s i n a c i d s o f t h e a b i e t a n e t y p e , p a l u s t r i c a n d n e o a b i e t i c a c i d s show a r e d u c t i o n f r o m t h e i r o r i g i n a l p e r c e n t a g e s i n t h e wood. P a l u s t r i c a c i d was r e d u c e d f r o m 0.037% t o 0.011% a n d n e o a b i e t i c f r o m 0.007% t o 0.002%. On t h e o t h e r h a n d , d e h y d r o a b i e t i c a n d a b i e t i c a c i d s show an i n c r e a s e f r o m t h e i r i n i t i a l c o n t e n t s i n t h e wood. The amount o f a b i e t i c a c i d i n c r e a s e d f r o m 0.017% i n wood t o 0.040%, a n d 137 d e h y d r o a b i e t i c a c i d i n c r e a s e d f r o m 0.059 i n wood t o 0.070% a f t e r p u l p i n g . F r o m t h i s d a t a i t a p p e a r s t h a t t h e r e s i n a c i d s o f t h e p i m a r a n e a n d i s o p i m a r a n e t y p e a r e r e c o v e r e d c o m p l e t e l y a f t e r p u l p i n g a n d t h a t t h e i r c h e m i c a l c h a r a c t e r i s t i c s r e m a i n e d u n c h a n g e d . However, p a l u s t r i c a n d n e o a b i e t i c a c i d a r e n o t r e c o v e r e d t o t a l l y , w h i l e a b i e t i c a n d d e h y d r o a b i e t i c a c i d s a p p a r e n t l y i n c r e a s e i n q u a n t i t y . T h i s l a s t f i n d i n g c a n be e x p l a i n e d a s t h e r e s u l t o f p r o b a b l e i s o m e r i z a t i o n o f p a l u s t r i c a n d n e o a b i e t i c a c i d i n t o d e h y d r o a b i e t i c a n d / o r a b i e t i c a c i d s . T h e r e i s e v i d e n c e t h a t d i e n i c r e s i n a c i d u n d e r a c i d o r b a s e c a t a l y z e d c o n d i t i o n s u n d e r g o e s i s o m e r i z a t i o n . S c h u l l e r a n d L a w r e n c e (1965) p r o p o s e d a m e c h a n i s m f o r t h e s e i s o m e r i z a t i o n s w h i c h i s g i v e n i n F i g . 2 1 . The p u l p i n g e x p e r i m e n t s w e re p e r f o r m e d u n d e r a c i d c o n d i t i o n s (20 m i n c o o k , pH 4 . 2 ) , a n d i t c a n be a s s u m e d t h a t p a l u s t r i c a n d n e o a b i e t i c a c i d s may u n d e r g o t h e same a c i d c a t a l y z e d r e a c t i o n s o f d i e n i c r e s i n a c i d s a s shown b y B a l d w i n e t a l . ( 1 9 5 6 ) , L a w r e n c e (1959) a n d S c h u l l e r e t al. ( 1 9 6 0 ) . 138 Figure 21. Proposed mechanism f o r the base-catalyzed isomerization of the conjugated d i e n i c r e s i n acids (Schuller and Lawrence, 1965) 139 I s o m e r i z a t i o n r e a c t i o n s o f r e s i n a c i d s d u r i n g o r g a n o s o l v p u l p i n g seem t o be d i f f e r e n t f r o m t h o s e t h a t o c c u r d u r i n g s e a s o n i n g o f t h e wood. U n d e r t h e l a t t e r c o n d i t i o n s t h e r e l a t i v e p r o p o r t i o n s o f d e h y d r o a b i e t i c a n d s a n d a r a c o p i m a r i c a c i d i n c r e a s e s u b s t a n t i a l l y a s e n d p r o d u c t s o f t h e i s o m e r i z a t i o n r e a c t i o n s . M e a n w h i l e , u n d e r o r g a n o s o l v p u l p i n g c o n d i t i o n s , d e h y d r o a b i e t i c a n d a b i e t i c a c i d s seem t o be t h e m a j o r e n d p r o d u c t s . I t a p p e a r s t h a t d u r i n g s t o r a g e u n d e r n a t u r a l c o n d i t i o n s , i n t h e p r e s e n c e o f e n z y m e s , t h e i s o m e r i z a t i o n r e a c t i o n l e a d s t o f o r m a t i o n o f d e h y d r o a b i e t i c a n d s a n d a r a c o p i m a r i c a c i d s . However, u n d e r t h e c o n d i t i o n s o f p u l p i n g a t pH 4.2 t o 5.0 i n m e t h a n o l i c medium a t h i g h t e m p e r a t u r e ( 2 0 5 2 C ) a n d e l e v a t e d p r e s s u r e , p a l u s t r i c a c i d t o g e t h e r w i t h n e o a b i e t i c a c i d a n d / o r any o t h e r u n i d e n t i f i e d d i e n i c a b i e t a n e r e s i n a c i d t y p e , a l l i s o m e r i z e - i n t o a b i e t i c o r d e h y d r o a b i e t i c a c i d a s s u g g e s t e d i n F i g . 21 . From t h e s e d a t a i t c a n be c o n c l u d e d t h a t among t h e r e s i n a c i d s o f t h e a b i e t a n e t y p e , a b i e t i c a n d d e h y d r o a b i e t i c a c i d s , u n d e r t h e s e v e r e c o n d i t i o n s o f o u r o r g a n o s o l v p u l p i n g c o n d i t i o n s , a r e t h e more s t a b l e e n d p r o d u c t s f r o m i s o m e r i z a t i o n r e a c t i o n s a n d more p r o b a b l y o r i g i n a t e f r o m p a l u s t r i c a n d n e o a b i e t i c a c i d s . A m e c h a n i s m f o r t h e s e i s o m e r i z a t i o n s ( F i g . 21) was p r o p o s e d e a r l i e r b y S c h u l l e r a n d L a w r e n c e ( 1 9 6 5 ) . 140 4.5.1.3. Resin- and f a t t y a c i d analysis a f t e r 40 min pulping Q u a n t i t a t i v e r e s u l t s o f r e s i n - a n d f a t t y a c i d s a f t e r 40 m i n o r g a n o s o l v p u l p i n g a r e g i v e n i n T a b l e 2 3 . I t c a n be s e e n t h a t a r o u n d 8 0% o f t h e o r i g i n a l t o t a l f a t t y a c i d s p r e s e n t i n wood a r e r e m o v e d a f t e r t h i s c o o k i n g p e r i o d . Out o f t h i s p o r t i o n , 60.4% a r e d i s s o l v e d i n t h e b l a c k l i q u o r , 1 9 . 0 % a r e a d s o r b e d o n t o t h e p r e c i p i t a t e d l i g n i n ( " L i g n i n I") a n d 1 1 . 7 % a r e e n t r a p p e d i n t h e p u l p . A l t h o u g h a f t e r 40 m i n p u l p i n g t h e p e r c e n t a g e o f p a l m i t i c a c i d i s h i g h e r t h a n t h a t f o u n d a f t e r 20 m i n p u l p i n g ( w h i l e t h e s t e a r i c a c i d c o n c e n t r a t i o n r e m a i n s a b o u t t h e same) t h e s e v a l u e s a r e s t i l l l o w e r t h a n t h e i r t o t a l a m o u nts p r e s e n t o r i g i n a l l y i n wood. A r o u n d 8 2 . 5 % o f t h e r e s i n a c i d s a r e r e m o v e d f r o m t h e wood. M o s t o f t h e a c i d s w e re e x t r a c t e d i n t h e b l a c k l i q u o r ( 6 9 . 4 % ) , a d s o r b e d o n t o t h e p r e c i p i t a t e d l i g n i n (13.1%) a n d e n t r a p p e d i n t h e p u l p ( 1 7 . 5 % ) . A g a i n , t h e more s t a b l e d e h y d r o a b i e t i c a n d a b i e t i c a c i d s were t h e o n l y r e s i n a c i d s f o u n d i n t h e p u l p . Table 23. Resin-and f a t t y acid composition i n slash pine wood a f t e r 40 min of organosolv p u l p i n g 8 Wood Black Precip Pulp Liquor Lignin Free Total Total Total Total TOTAL Fatty acids: P a l m i t i c 0.015 0.133 0.051 0.008 0.015 0.074 S t e a r i c 0.009 0.042 0.006 0.003 0.012 0.021 O l e i c 0.019 0.124 0.099 0.036 0 . 009 0.144 L i n o l e i c 0.005 0.015 0.034 0.012 0.001 0.047 L i n o l e n i c N.D. 0.002 0.001 0.001 0.002 TOTAL 0.048 0.316 0.191 0.060 0 . 037 0.288 Resin Acids: P i m a r i c 0.028 0.024 0.005 • • • 0.029 S a n d a r a c o p i m a r i c 0.008 0.007 0.002 ... 0.009 I s o p i m a r i c 0.050 0.037 0.007 • . . 0.044 P a l u s t r i c 0.037 0.010 0.002 • • • 0.012 D e h y d r o a b i e t i c 0.059 0.042 0.004 0 . 024 0.070 A b i e t i c 0.017 0.022 0.006 0.012 0.040 N e o a b i e t i c 0.007 0.001 0.001 0.002 TOTAL 0.206 0.143 0.027 0.036 0.206 a A l l v a l u e s a r e p e r c e n t a g e s on O.D. wood b a s i s . 142 C o m p a r i n g t h e s e d a t a w i t h t h o s e o b t a i n e d a f t e r 2 0 m i n u t e s p u l p i n g , a g a i n t h e c o n c e n t r a t i o n o f p i m a r i c , i s o p i m a r i c a n d s a n d a r a c o p i m a r i c a c i d s was n e a r l y t h e same a s t h a t f o u n d i n t h e wood. However, t h e c o n t e n t s o f p a l u s t r i c a n d n e o a b i e t i c a c i d s d e c r e a s e d , w h i l e t h e p e r c e n t a g e s o f a b i e t i c a n d d e h y d r o a b i e t i c a c i d s i n c r e a s e d due t o t h e h i g h t e m p e r a t u r e , t r e a t m e n t . A g a i n , t h i s m i g h t be e x p l a i n e d i n t e r m s o f t h e i s o m e r i z a t i o n r e a c t i o n s o f b o t h p a l u s t r i c a n d n e o a b i e t i c a c i d s l e a d i n g t o t h e i r c o n v e r s i o n i n t o a b i e t i c (See F i g . 21) a n d / o r d e h y d r o a b i e t i c a c i d . 4.5.1.4. Resin- and f a t t y acids analysis a f t e r 60 min pulping Q u a n t i t a t i v e r e s u l t s o f t h e r e s i n - a n d f a t t y a c i d s a f t e r 60 m i n p u l p i n g a r e g i v e n i n T a b l e 24. O r g a n o s o l v p u l p i n g f o r 60 m i n p e r m i t s s u b s t a n t i a l r e m o v a l o f t h e f a t t y a c i d s (91.8%) a n d r e s i n a c i d s (88.3%) f r o m t h e wood. M o s t o f t h e f a t t y a c i d s w e r e d e t e c t e d i n t h e b l a c k l i q u o r ( 7 1 . 6 % ) * a n d t h e r e s t p r o p o r t i o n e d b e t w e e n t h e p r e c i p i t a t e d l i g n i n ( 2 0 . 2 % ) * a n d t h e p u l p ( 8 . 2 % ) * . * T h e s e v a l u e s a r e b a s e d on t h e t o t a l f a t t y a c i d c o n t e n t d e t e c t e d a f t e r p u l p i n g . Table 24. Resin-and f a t t y acid composition i n slash pine wood afte r 60 min of organosolv p u l p i n g 3 Wood Black Precip Pulp Liquor Lignin Free Total Total Total Total TOTAL Fatty acids: P a l m i t i c 0.015 0.133 0.078 0.009 0.011 0.098 S t e a r i c 0.009 0.042 0.005 0.003 0.009 0.017 O l e i c 0.019 0.124 0 .108 0.041 0.007 0.156 L i n o l e i c 0.005 0.015 0.053 0.015 0.001 0.069 L i n o l e n i c N.D. 0.002 0.001 0.001 • • • • 0.002 TOTAL 0.048 0 .316 0.245 0.069 0.028 0.342 Resin Acids: P i m a r i c 0.028 0 . 031 0.004 • • • 0.035 S a n d a r a c o p i m a r i c 0.008 0 . 012 0.002 • • • 0.014 I s o p i m a r i c 0.050 0.038 0.006 • • • 0.044 P a l u s t r i c 0.037 0.014 N.D. • • • 0.014 D e h y d r o a b i e t i c 0.059 0.044 0.006 0.021 0.071 A b i e t i c 0.017 0.021 0.003 0.003 0.027 N e o a b i e t i c 0.007 N.D • • • • • • • • N.D. TOTAL 0.206 0.160 0.021 0.024 0.205 a A l l v a l u e s a r e p e r c e n t a g e s on O.D. wood b a s i s . 144 P a l m i t i c , o l e i c and l i n o l e i c a c i d s are d e t e c t e d i n h i g h e r amounts and f o l l o w e d the same t r e n d as found e a r l i e r with the 40-minute p u l p i n g . Again, even though the p a l m i t i c a c i d r e c o v e r y a f t e r the 60 min p u l p i n g i s g r e a t e r than a f t e r 40 min, the t o t a l amount r e c o v e r e d (0.098%) r e p r e s e n t s o n l y 75% of i t s o r i g i n a l content i n the wood (0.133%). O l e i c and l i n o l e i c a c i d s are found i n h i g h e r c o n c e n t r a t i o n s a f t e r p u l p i n g than o r i g i n a l l y d e t e c t e d i n wood. Again, i t might be s p e c u l a t e d t h a t these increments c o u l d be e i t h e r the r e s u l t of b e t t e r h y d r o l y s i s of the f a t s a f t e r p u l p i n g than by s a p o n i f i c a t i o n or t h a t some un-i d e n t i f i e d f a t t y a c i d s may have i s o m e r i z e d i n t o these two a c i d s . P u l p i n g t r i a l s of the r e s p e c t i v e model compounds f o r the methyl d e r i v a t i v e s of s t e a r i c , o l e i c , l i n o l e i c and l i n o l e n i c a c i d s were performed i n order t o c l a r i f y some of these above r e s u l t s . A l l these methyl d e r i v a t i v e s were t r e a t e d at 205 2C f o r 60 min. S t e a r i c a c i d , as an example of a s a t u r a t e d f a t t y a c i d , d i d not s u f f e r any chemical change under the above c o n d i t i o n s . On the o t h e r hand, u n s a t u r a t e d f a t t y a c i d s ( i . e . o l e i c , l i n o l e i c and l i n o l e i c ) m a n i f e s t e d some chemical changes. Oleate ( C ^ . ^ ) and l i n o l e a t e methyl e s t e r s s u f f e r e d r e d u c t i o n s from t h e i r o r i g i n a l contents of 20% and 90%, r e s p e c t i v e l y . Furthermore, organosolv p u l p i n g of, l i n o l e n a t e (Ci8*3) 145 m e t h y l e s t e r r e v e a l e d t h a t u n d e r t h e p r e s e n t c o n d i t i o n s i t i s c o m p l e t e l y d e g r a d e d . The t r e n d o f d e g r a d a t i o n f o r t h e s e t h r e e f a t t y a c i d m e t h y l e s t e r d e r i v a t i v e s i s s i m i l a r t o t h e one o b s e r v e d d u r i n g t h e i r a u t o o x i d a t i o n r e a c t i o n s . A c c o r d i n g t o Holman ( 1 9 6 5 ) , t h e m e t h y l e n e - i n t e r r u p t e d p o l y u n s a t u r a t e d a c i d s , b e c a u s e o f t h e i r a c t i v a t e d m e t h y l e n e g r o u p s , a r e v e r y e a s i l y a t t a c k e d b y o x y g e n . He s u g g e s t e d t h a t t h i s a u t o o x i d a t i o n r e a c t i o n g o e s t h r o u g h a f r e e r a d i c a l f o r m a t i o n a n d t h a t i t s r a t e i s d e p e n d e n t u p o n t h e d e g r e e o f u n s a t u r a t i o n o f t h e f a t t y a c i d s . He a d d e d t h a t t h e r a t e o f o x i d a t i o n f o r l i n o l e a t e i s a p p r o x i m a t e l y 20 t i m e s t h a t o f o l e a t e due t o t h e d o u b l e a c t i v a t i o n o f t h e m e t h y l e n e g r o u p i n t h e f o r m e r . F r o m t h e p r e v i o u s i n f o r m a t i o n i t i s p o s s i b l e t o p r o p o s e t h a t t h e d e g r a d a t i o n o f t h e u n s a t u r a t e d f a t t y a c i d s i s r e l a t e d t o t h e number o f r e a c t i v e s i t e s ( d o u b l e b o n d s ) i n t h e m o l e c u l e . S i n c e l i n o l e i c a c i d h a s more d o u b l e b o n d s , t h i s m o l e c u l e must show g r e a t e r d e g r a d a t i o n . I n o u r e x p e r i m e n t s , m e t h y l l i n o l e n a t e ( C 1 8 * 3 ^ w a s c o m p l e t e l y d e s t r o y e d a f t e r o r g a n o s o l v p u l p i n g a t 2 0 5 2 C f o r 60 m i n . F r o m t h e t o t a l r e s i n a c i d s d e t e c t e d a f t e r p u l p i n g , o n l y 1 1 . 7 % r e m a i n e d i n t h e p u l p ; t h e b u l k was d i s t r i b u t e d b e t w e e n t h e b l a c k l i q u o r (78.1%) a n d t h e p r e c i p i t a t e d l i g n i n ( 1 0 . 2 % ) . D e h y d r o a b i e t i c a n d a b i e t i c a c i d s w e re t h e 146 o n l y r e s i n a c i d s l e f t i n t h e p u l p . T h e s e r e s i d u a l a c i d s i n t h e p u l p c a n be e x p l a i n e d i n t e r m s o f t h e i r l o w e r s o l u b i l i t y i n m e t h a n o l a n d a l s o b e c a u s e o f t h e h i g h e r c o n t e n t i n t h e wood. C o n s i d e r i n g t h e i n i t i a l c o n t e n t s , i t i s v e r y l i k e l y t h a t t h e r e must r e m a i n some r e s i d u e s o f t h e o t h e r r e s i n a c i d s i n t h e p u l p , b u t t h e amounts a r e t o o l o w t o b e d e t e c t e d . P i m a r i c a n d s a n d a r a c o p i m a r i c a c i d s b o t h i n c r e a s e d b y t h e same a m o u n t s , w h i l e i s o p i m a r i c a c i d d e c r e a s e d b y t h e same amount. I n t h i s c a s e i t w o u l d be more a p p r o p r i a t e t o assume t h a t i s o p i m a r i c a c i d i s o m e r i z e d i n t o s a n d a r a c o p i m a r i c a c i d i n s t e a d o f p i m a r i c a c i d . I s o m e r i z a t i o n o f i s o p i m a r i c a c i d i n t o s a n d a r a c o p i m a r i c a c i d s u g g e s t s o n l y a s h i f t i n t h e d o u b l e b o n d f r o m t h e 7 p o s i t i o n i n i s o p i m a r i c a c i d t o t h e 8 ( 1 4 ) p o s i t i o n i n s a n d a r a c o p i m a r i c a c i d . I s o m e r i z a t i o n o f i s o p i m a r i c a c i d i n t o p i m a r i c a c i d i n c l u d e s n o t o n l y t h e m i g r a t i o n o f t h i s d o u b l e b o n d , b u t a l s o t h e c h a n g e i n t h e c o n f i g u r a t i o n o f c a r b o n C-13. P u l p i n g e x p e r i m e n t s o f t h e i s o p i m a r a t e m e t h y l d e r i v a t i v e (model compound) showed t h a t t h i s a c i d i s o m e r i z e s i n t o p i m a r i c ( 1 . 8 % ) , s a n d a r a c o p i m a r i c ( 1 . 4 % ) , d e h y d r o a b i e t i c a c i d (3.8%) a n d o t h e r m i n o r compounds n o t i d e n t i f i e d . A l s o , a d d i t i o n a l c o o k i n g s o f p i m a r i c a n d s a n d a r a c o p i m a r i c a c i d d e m o n s t r a t e d t h a t t h e s e t w o a c i d s do 147 n o t s u f f e r a n y c h e m i c a l c h a n g e s u n d e r t h e p r e s e n t c o n d i t i o n s (60 m i n a t 2 0 5 2 C ) . F u r t h e r m o r e , c o o k i n g o f m e t h y l s a n d a r a c o p i m a r a t e , w h i c h c o n t a i n e d m e t h y l i s o p i m a r a t e a s i m p u r i t y i n a 8:1 r a t i o , r e n d e r e d a f i n a l s a n d a r a c o p i m a r a t e - p i m a r a t e -i s o p i m a r a t e r a t i o o f ( 1 2 : 1 : 1 ) . F r o m t h e s e r e s u l t s i t i s p o s s i b l e t o c o n c l u d e t h a t o r g a n o s o l v p u l p i n g p r o v o k e s t h e i s o m e r i z a t i o n o f i s o p i m a r i c a c i d i n t o p i m a r i c a n d s a n d a r a c o p i m a r i c a c i d s . Among t h e a b i e t a n e r e s i n a c i d s t y p e , d e h y d r o a b i e t i c a n d a b i e t i c a c i d show t h e h i g h e s t c o n t e n t s among t h e m a j o r r e s i n a c i d s f o u n d a f t e r p u l p i n g . D e h y d r o a b i e t i c a c i d i n c r e a s e d f r o m 0.059% i n t h e wood t o 0.071% a f t e r p u l p i n g , w h i l e a b i e t i c a c i d p r e s e n t e d a n o t i c e a b l e i n c r e m e n t f r o m 0 . 0 1 7 t o 0.027%. T h i s l a t t e r v a l u e i s l o w e r t h a n t h a t a f t e r t h e 40 m i n c o o k w h i c h c a n b e e x p l a i n e d i n t e r m s o f d e g r a d a t i o n o f t h e a b i e t i c a c i d b e c a u s e o f l o n g e r r e s i d e n c e t i m e (60 min) d u r i n g t h e p u l p i n g p r o c e s s . H o w e v e r , p a l u s t r i c a n d n e o a b i e t i c a c i d s e x h i b i t t h e l o w e s t c o n t e n t s among t h e r e s i n a c i d s . P a l u s t r i c a c i d was r e d u c e d f r o m 0.037% i n t h e wood t o 0.014% a f t e r p u l p i n g , w h i l e n e o a b i e t a t e d i s s a p p e a r e d c o m p l e t e l y a f t e r p u l p i n g . O r g a n o s o l v p u l p i n g o f t h e m o d e l c o m p o u n d o f m e t h y l d e h y d r o a b i e t a t e f o r 60 m i n a t 2 0 5 ° C r e v e a l s t h a t t h i s a c i d d o e s n o t s u f f e r a n y c h e m i c a l c h a n g e d u r i n g t h e s e c o n d i t i o n s . H o w e v e r , p u l p i n g o f m e t h y l p a l u s t r a t e a n d 148 methyl abietate rendered t h e i r comprehensive isomerization into methyl dehydroabietate. And s u r p r i s i n g l y , methyl neoabietate was completely degraded under the same organosolv pulping conditions. Loeblich et al. (1955b) found that p a l u s t r i c acid on treatment with mineral acid i s isomerized to a b i e t i c acid. They indicated that the isomerization of p a l u s t r i c acid into a b i e t i c acid was approximately 90% complete. They also found that levopimaric acid isomerized into p a l u s t r i c acid a f t e r heating at 155 2C for about 5 h. The amount of p a l u s t r i c acid was 29.0% of the isomerized products. Furthermore, they postulated that p a l u s t r i c acid i s an intermediate product i n the acid and that heat isomerization of levopimaric to a b i e t i c acid also occurs. The present findings seem to contradict the r e s u l t s obtained i n the past, i n which a b i e t i c acid was the end product of thermal, acid and base catalyzed isomerization of p a l u s t r i c , neoabietic and levopimaric acids (Loeblich et al., 1955a; Loeblich et al., (1955b); Baldwin et a l . , 1956; Loeblich and Lawrence, 1957; Schuller et al., 1960; Schuller and Lawrence, 1965). It has been shown that the end products formed by thermal isomerization of neoabietic acid at 200 2C consist p r i m a r i l y of p a l u s t r i c and a b i e t i c acid. A f t e r a 72 h reaction, the products approached an equilibrium mixture of 13% p a l u s t r i c acid, 82% a b i e t i c acid and 5% neoabietic 149 a c i d ( L o e b l i c h a n d L a w r e n c e , 1957) . I t was a l s o f o u n d t h a t n e o a b i e t i c a c i d i s more r e a d i l y i s o m e r i z e d t o a b i e t i c a c i d t h a n t o p a l u s t r i c a c i d , w h e r e a s l e v o p i m a r i c a c i d f o r m s b o t h o f t h e s e a c i d s w i t h e q u a l e a s e . (See T a b l e 25) . F u r t h e r m o r e , a n a l y s i s o f t h e p r o d u c t s a f t e r a 30 m i n i s o m e r i z a t i o n o f n e o a b i e t i c a n d l e v o p i m a r i c a c i d s a t 200 2C showed t h a t n e o a b i e t i c a c i d i s more s t a b l e t o h e a t t h a n l e v o p i m a r i c a c i d ( L o e b l i c h a n d L a w r e n c e , 1957). (See T a b l e 25) . Table 25. Thermal Isomerization of Neoabietic and Levopimaric a c i d at 200fiC f o r 30 min (Loeblich and Lawrence, 1957) P a l u s t r i c A b i e t i c Neoabietic % % % L e v o p i m a r i c A c i d 34 52 14 N e o a b i e t i c A c i d 5 11 84 A c c o r d i n g t o L o e b l i c h e t al. ( 1 9 5 5 a ) , t h e r m a l i s o m e r i z a t i o n o f l e v o p i m a r i c a c i d b e t w e e n 155 a n d 2 0 0 Q C g i v e s p a l u s t r i c , a b i e t i c a n d n e o a b i e t i c a c i d s a s t h e e n d p r o d u c t s . T h e s e a n a l y s e s w e r e p e r f o r m e d i n o r d e r t o u n d e r s t a n d t h e r e a c t i o n s t h a t t a k e p l a c e when o l e o r e s i n i s p r o c e s s e d i n t o r o s i n by d i s t i l l a t i o n . They f o u n d t h a t v e r y l i t t l e , i f a n y , i s o m e r i z a t i o n o f t h e c r y s t a l l i n e a c i d o c c u r r e d b e l o w i t s m e l t i n g p o i n t (m.p. 1 5 0 - 1 5 2 2 ) . 150 F u r t h e r m o r e , t h e y d i s c o v e r e d t h a t i s o m e r i z a t i o n o f l e v o p i m a r i c a c i d a t 200 e C was f o u n d t o be a b o u t e i g h t t i m e s a s f a s t a s t h e i s o m e r i z a t i o n a t 1 5 5 2 C . (See T a b l e 26) . Table 26. Thermal Isomerization of Levopimaric Acid at 155 and 200&C (Loeblich et al., 1955a) Temp., Time P a l u s t r i c A b i e t i c Neoabietic oc. h. % % % 155 4 35 52 14 200 0.5 34 52 14 C o n t r a r y t o t h e f i n d i n g s g i v e n i n t h e l i t e r a t u r e a b o v e ( a c i d , b a s e a n d h e a t c a t a l y z e d i s o m e r i z a t i o n s ) , o r g a n o s o l v p u l p i n g o f t h e m o d e l compounds o f m e t h y l a b i e t a t e a t 2 0 0 S C d u r i n g 60 m i n r e v e a l s i t s c o m p l e t e i s o m e r i z a t i o n i n t o d e h y d r o a b i e t i c a c i d . T h i s r e s u l t n o t o n l y c o n t r a d i c t e d t h o s e r e s u l t s g i v e n i n t h e l i t e r a t u r e , b u t a l s o t h o s e o b t a i n e d a f t e r o r g a n o s o l v p u l p i n g o f s l a s h p i n e wood s a m p l e s . I t was o b s e r v e d t h a t t h e a b i e t i c a c i d c o n t e n t i n c r e a s e d f r o m 0.017% i n t h e wood t o 0.040% a f t e r 20 a n d 40 m i n c o o k s a n d t o 0.027% a f t e r a 60 m i n c o o k . I t was a s s u m e d (See s e c t i o n s 4.5.1.2 a n d 4.5.1.3) t h a t t h o s e i n c r e m e n t s w e r e p r o d u c e d b e c a u s e o f i s o m e r i z a t i o n s o f p a l u s t r i c a n d n e o a b i e t i c a c i d s i n t o a b i e t i c a c i d . S i n c e i t was f o u n d t h a t o r g a n o s o l v p u l p i n g o f t h e m o d e l compounds 151 of a b i e t i c and p a l u s t r i c acids isomerized into dehydroabietic acid and that neoabietic acid was destroyed, i t was necessary to f i n d an explanation for the su r v i v a l of a b i e t i c acid a f t e r pulping of slash pine wood. It was expected that pulping of a b i e t i c acid i n combination with s i m i l a r r e s i n acids of the abietane ( i . e . neoabietic and p a l u s t r i c acids) type may induce or favor a strange mechanism for t h e i r isomerization into a b i e t i c acid. With t h i s i n mind, a b i e t i c acid was pulped with p a l u s t r i c and levopimaric acids i n a (1:1:1) r a t i o , and again the main product was dehydroabietic acid. Further attempts were performed i n order to understand the d i f f e r e n t behaviour of a b i e t i c acid not only as a model compound but also as a component of the wood during pulping. In order to simulate part of the wood environment, a 5 g sample of pure AVICEL (Hercules Co.) was added to the methyl abietate sample and pulped at 2 0 5 2 at pH 3.3 for 60 min. The pH was adjusted with 10% acetic acid solution. Again, the end product of t h i s reaction was dehydroabietic acid. The f i n a l t r i a l s from these series of experiments were the pulping of model a b i e t i c acid (free acid) at 20 and 60 min. The purpose of these t r i a l s was to compare the d i f f e r e n t behavior of the free acid against i t s methyl derivative and also to investigate the e f f e c t of two 152 c o o k i n g p e r i o d s ( r e s i d e n c e t i m e ) on t h e i s o m e r i z a t i o n o f a b i e t i c a c i d . GC a n a l y s e s o f a b i e t i c a c i d a f t e r a 20 m i n c o o k r e v e a l e d t h e p r e s e n c e o f d e h y d r o a b i e t i c a c i d . The o r i g i n a l amount o f a b i e t i c a c i d was r e d u c e d t o 55%, w h i l e t h e r e m a i n d e r (45%) was c o n v e r t e d t o d e h y d r o a b i e t i c a c i d . H owever, p u l p i n g f o r 60 m i n a g a i n showed t h e c o m p l e t e d i s a p p e a r a n c e o f a b i e t i c a c i d . T h e s e r e s u l t s i n d i c a t e t h a t a b o u t h a l f o f t h e a b i e t i c a c i d d u r i n g a 20 m i n p u l p i n g i s d e p l e t e d ( i s o m e r i z e d ) , w h i l e a f t e r a 60 m i n c o o k , i t i s c o m p l e t e l y i s o m e r i z e d i n t o d e h y d r o a b i e t i c a c i d . T h e s e f i n d i n g s may c o n t r a d i c t a l l p r e v i o u s a s s u m p t i o n s t h a t a b i e t i c a c i d c o u l d h a v e b e e n t h e e n d p r o d u c t f r o m i s o m e r i z a t i o n o f p a l u s t r i c a n d n e o a b i e t i c a c i d s d u r i n g o r g a n o s o l v p u l p i n g o f s l a s h p i n e wood. T h e s e r e s u l t s s u g g e s t t h a t o r g a n o s o l v p u l p i n g o f t h e m e t h y l e s t e r a n d f r e e f o r m o f a b i e t i c a c i d a f t e r a 60 m i n . c o o k s p r o v o k e s i t s i s o m e r i z a t i o n i n t o d e h y d r o a b i e t i c a c i d . F u r t h e r m o r e , i t i s p o s s i b l e t o c o n c l u d e t h a t i s o m e r i z a t i o n o f a b i e t i c a c i d i n t o d e h y d r o a b i e t i c a c i d d u r i n g o r g a n o s o l v p u l p i n g i s a t i m e d e p e n d e n t r e a c t i o n . E v e n t h o u g h o r g a n o s o l v p u l p i n g o f t h e m o d e l compound f o r a b i e t i c a c i d e v i d e n c e s i t s i s o m e r i z a t i o n i n t o d e h y d r o a b i e t i c a c i d , o r g a n o s o l v p u l p i n g o f s l a s h p i n e wood d o e s n o t g i v e t h e same r e s u l t s . The f o l l o w i n g a r g u m e n t s 153 may e x p l a i n t h e h i g h p e r c e n t a g e s o f a b i e t i c a c i d o b s e r v e d a f t e r o r g a n o s o l v p u l p i n g o f t h e wood: a) . D u r i n g t h e p u l p i n g p r o c e s s , wood may p r o t e c t t h i s a c i d f r o m t h e s e v e r i t y o f t h e h i g h t e m p e r a t u r e a n d p r e s s u r e o f t h e p u l p i n g e x p e r i m e n t s . T h i s p o s s i b i l i t y i s s u p p o r t e d b y t h e f a c t t h a t a b i e t i c a n d d e h y d r o a b i e t i c a c i d s a r e t h e o n l y a c i d s l e f t i n t h e p u l p . b) . One wood c o n s t i t u e n t o r a g r o u p o f t h e wood c o n s t i t u e n t s may i n d u c e t h e s e l e c t i v e o r s t e r e o s p e c i f i c f o r m a t i o n o f an a d d u c t w h i c h i s r e s i s t a n t t o t h e p u l p i n g c o n d i t i o n s . T h i s p o s s i b i l i t y s u g g e s t s t h a t a f u r t h e r s e r i e s o f e x p e r i m e n t s s h o u l d be c o n d u c t e d w i t h a b i e t i c a c i d u n d e r t h e p u l p i n g c o n d i t i o n s w i t h t h e a d d i t i o n o f a s i n g l e o r m u l t i p l e c o m p o n e n t s o f t h e wood c o n s t i t u e n t s o f s l a s h p i n e wood. c) . T h e r e may be a s m a l l s t e r i c d i f f e r e n c e b e t w e e n t h e n a t u r a l a n d s y n t h e t i c f o r m s o f a b i e t i c a c i d , a n d t h e s e two f o r m s may b e h a v e d i f f e r e n t l y d u r i n g p u l p i n g . T h e r e f o r e , one c a n s p e c u l a t e t h a t t h e n a t u r a l f o r m i s more t h e r m o s t a b l e t h a n t h e s y n t h e t i c o n e. F a t t y a n d r e s i n a c i d s s u r v i v i n g t h e h i g h - t e m p e r a t u r e p u l p i n g p r o c e s s w e re f o u n d m a i n l y i n t h e b l a c k l i q u o r ( 7 8 . 1 % a n d 71.6%, r e s p e c t i v e l y ) . T h e r e m a i n i n g f r a c t i o n s w e r e d e t e c t e d i n t h e p u l p ( 1 1 . 7 % a n d 8.2%, r e s p e c t i v e l y ) a n d a d s o r b e d o n t o t h e l i g n i n ( 1 0 . 2 % a n d 2 0 . 2 % , r e s p e c t i v e l y ) . However, i t i s n o t u n r e a s o n a b l e t o 154 s u g g e s t t h a t a t t h e c o o k i n g t e m p e r a t u r e u s e d , a l l e x t r a c t i v e s r e m o v e d were d i s s o l v e d i n t h e c o o k i n g l i q u o r a n d t h a t L i g n i n I ( p r e c i p i t a t e ) m e r e l y e n t r a p p e d some o f t h e e x t r a c t i v e s . O r i g i n a l l y , i t was a s s u m e d t h a t t h i s l i g n i n p r e c i p i t a t e d b e c a u s e o f a s i d e r e a c t i o n w i t h e x t r a c t i v e s , h o w e v e r s i n c e t h e e x t r a c t i v e s a r e r e a d i l y r e m o v e d f r o m t h e l i g n i n w i t h n o n - p o l a r s o l v e n t s , i t i s a p p a r e n t , t h a t t h e e x t r a c t i v e s a r e m e r e l y a d s o r b e d on t h e p o r o u s , h o l l o w g l o b u l a r p r e c i p i t a t e d l i g n i n p a r t i c l e s ( P a s z n e r a n d Cho, 1 9 8 8 ) . S u m m a t i v e r e s u l t s o f t h e r e s i n - a n d f a t t y a c i d c o m p o s i t i o n a f t e r 5, 20, 40 a n d 60 m i n u t e s p u l p i n g a r e g i v e n i n T a b l e 27. The t o t a l o f t h e r e s i n - a n d f a t t y a c i d s c o n t e n t s i n t h e p u l p w e re as f o l l o w s : a f t e r 20 min= 0.092%, a f t e r 40 min= 0.073% a n d a f t e r 60 min= 0.052%. The t o t a l r e s i n a c i d s r e m o v e d f r o m t h e wood a r e a s f o l l o w s : a f t e r 5 min= 0.185%, a f t e r 20 min= 0.161%, a f t e r 40 min= 0.170% a n d a f t e r 60 min= 0.181%. I t i s q u i t e c l e a r t h a t t h e r e s i n a c i d s a r e e a s i l y r e m o v e d e v e n a f t e r a v e r y s h o r t c o o k i n g t i m e (5 m i n ) . On t h e o t h e r h a n d , r e m o v a l e f f i c i e n c y o f t h e f a t t y a c i d s was l o w a f t e r t h e 5 m i n c o o k ( 2 5 . 0 % ) , b u t i n c r e a s e d r a p i d l y a f t e r t h e 20 m i n c o o k ( 6 0 . 0 % ) , 40 m i n c o o k (80.0%) a n d t h e 60 m i n c o o k ( 9 2 . 0 % ) . I n a l l o f t h e s e c a s e s i t must be a s s u m e d t h a t t h e r e s t o f t h e f a t t y a c i d s r e m a i n i n t h e p u l p . Table 27. Fatty-and resin acid composition* of slash pine wood and t h e i r recovery a f t e r 5, 20, 40 and 60 min organosolv pulping Wood Pulping Time (min) 5 20 40 60 Fatty acids: FA TA TA TA TA TA P a l m i t i c 0 . 015 0 .133 0 . 009 0 . 0 5 5 0 .074 0 .098 S t e a r i c 0 . 009 0 .042 0 .002 0 . 023 0 .021 0 .017 O l e i c 0 . 019 0 .124 0 .047 0 . 123 0. 0144 0 . 1 5 6 L i n o l e i c 0 .005 0 .015 0 .022 0 . 037 0 .047 0 . 0 6 9 L i n o l e n i c N . D . 0 .002 0 .001 0 .002 0 .002 - 0 .002 T O T A L S 0 .048 0 .316 0 .081 0 .240 0 .288 0 .342 Resin Acids: P i m a r i c 0 .028 0 . 029 0 . 0 2 9 0 . 0 2 9 0 . 0 3 5 S a n d a r a c o p i m . 0 .008 0 . 009 0 .008 0 . 0 0 9 0 .014 I s o p i m a r i c 0 .050 0 .051 0 . 043 0 . 0 4 5 0 .044 P a l u s t r i c 0 .037 0 . 005 0 .011 0 .012 0 .014 D e h y d r o a b i e t i c 0 . 059 0 .051 0 .070 0 .070 0 .071 A b i e t i c 0 .017 0 .038 0 .040 0 .040 0 . 027 N e o a b i e t i c 0 . 007 0 .002 0 .001 0 .002 N . D . T O T A L S 0 .206 0 .185 0 .202 0 .207 0 . 205 * V a l u e s c o r r e s p o n d t o p e r c e n t a g e s (%) b a s e d on O . D . w o o d . * * N . D . = n o t d e t e c t e d , s i g n a l p e a k s t o o s m a l l t o be d e t e c t e d by t h e i n t e g r a t o r . 156 4.5.1.5. Complementary analyses of the r e s i n - and f a t t y a c i d a f t e r high pressure 60 min cooks C o n t r a r y t o t h e f r a c t i o n a t i o n p r o c e d u r e s f o l l o w e d f o r t h e e x t r a c t i v e a n a l y s e s a f t e r 5 , 2 0 , 40 a n d 60 m i n c o o k i n g s a s d e s c r i b e d a b o v e , when t h e t o t a l l i g n i n i n a 60 m i n b l a c k l i q u o r i s p r e c i p i t a t e d w i t h a n e x c e s s amount o f w a t e r (1 :10 r a t i o ) a n o t h e r t y p e o f l i g n i n ( L i g n i n I I ) was o b t a i n e d . On q u a n t i t a t i v e a n a l y s i s o f t h e d i l u t e d b l a c k l i q u o r (See s e c t i o n 3 . 5 . 2 . 1 . 3 ) a n d t h e p r e c i p i t a t e d l i g n i n (See s e c t i o n 3 . 5 . 2 ) , i t was f o u n d t h a t 98.2% o f r e s i n a c i d s a n d 60.4% o f f a t t y a c i d s were a d s o r b e d o n t o t h e l i g n i n . T h e r e s t o f t h e s e c o m p o u n d s . r e m a i n e d d i s s o l v e d i n t h e a q u e o u s f i l t r a t e . T h i s h a s i m p o r t a n t c o n n o t a t i o n s a s t o t h e e x p e c t e d p o l l u t i o n l o a d s f r o m s o f t w o o d e x t r a c t i v e s i n t h e a q u e o u s r e s i d u e f o l l o w i n g r e m o v a l o f t h e l i g n i n b y f i l t r a t i o n / c e n t r i f u g a t i o n f r o m t h e o r g a n o s o l v b l a c k l i q u o r . T h e r e b y , l i g n i n p r e c i p i t a t i o n e f f e c t i v e l y r e m o v e s t h e s e t o x i c s u b s t a n c e s ( p a r t i c u l a r l y t h e more t o x i c r e s i n a c i d s ) f r o m t h e p u l p i n g e f f l u e n t s . Some r e c e n t l y p u b l i s h e d r e s u l t s b y O r g a n o c e l l (MD P a p i e r ) ( D a h l m a n n a n d S c h r o e t e r , 1 9 9 0 ; P a p p e n s , 1990) c o n f i r m t h e s e f i n d i n g s . C o n v e r s e l y , o r g a n o s o l v l i g n i n s d i r e c t l y p r e c i p i t a t e d f r o m b l a c k l i q u o r w i l l b e c o n t a m i n a t e d b y e x t r a c t i v e s u n l e s s r e m o v e d b y s o l v e n t e x t r a c t i o n . 157 4.6. Characterization of Lignins I t h a s b e e n p r o v e n t h a t o r g a n o s o l v l i g n i n i s u n c o n d e n s e d , l o w m o l e c u l a r w e i g h t a n d f r e e o f s u l f u r (Nimz a n d C a s t e n , 1985; Young e t al., 1 9 8 5 ) . T h e r e f o r e , a s u i t a b l e e x t r a c t i o n a n d p u r i f i c a t i o n t e c h n i q u e w i l l n o t o n l y e n s u r e t h e y i e l d o f a n o t h e r h i g h v a l u e b y - p r o d u c t i n t h e f o r m o f t h e e x t r a c t i v e s , b u t a l s o t h e p r o c e d u r e w i l l p r o d u c e a p u r e r r e s i d u a l l i g n i n w h i c h m i g h t be c o n s i d e r e d a s a c o n v e n i e n t m a t e r i a l a s a p h e n o l s u b s t i t u t e i n a d h e s i v e s f o r p a r t i c l e b o a r d s , a n d o t h e r r e s i n - t y p e p r o d u c t s ( p o l y u r e t h a n e s ) , o r a s a c h e m i c a l f e e d s t o c k ( m a n u f a c t u r e o f a r o m a t i c s a n d l i q u i d f u e l s ) . 4.6.1. Quantitative analysis of l i g n i n Due t o t h e d i f f e r e n t c o o k i n g t i m e s u s e d d u r i n g t h e p u l p i n g e x p e r i m e n t s , e s t a b l i s h m e n t o f a mass b a l a n c e was n e c e s s a r y i n o r d e r t o f o l l o w p o s s i b l e l o s s e s d u r i n g t h e w h o l e p u l p i n g a n a l y s i s p r o c e d u r e s . Mass b a l a n c e s w e re d e t a i l e d s p e c i f i c a l l y f o r l i g n i n , r e s i n - a n d f a t t y a c i d s , a n d r o u t i n e p u l p y i e l d a n a l y s e s w e re a l s o u n d e r t a k e n . Q u a n t i t a t i v e r e s u l t s f o r p u l p y i e l d , l i g n i n , r e s i n a c i d s a n d f a t t y a c i d s a r e g i v e n i n T a b l e 28. F r o m t h i s t a b l e , i t c a n be s e e n t h a t e v e n a f t e r 60 m i n o f c o o k i n g , a h i g h p u l p y i e l d o f 5 4 . 5 % i s o b t a i n e d . Table 28. Mass balance of l i g n i n , r e s i n and f a t t y acids of slash pine wood a f t e r organosolv p u l p i n g 3 Pulping Time (minutes) 20 40 60 WOOD Pulp y i e l d 71.0 59.0 54.5 100.0 Lignin a) Organosolv l i g n i n : Lignin I,% 4.91 7.14 7.61 Lignin S,% 7.06 7.09 8.85 Lignin P, % 3.16 2.54 2.39 Lignin l e f t i n pulp (K No) b, % 12.50 11.05 8.80 b) Lignin from wood 28.2° Acid-insoluble, % 26.8 Acid-soluble, % 1.4 Resin Acids 0.204 0.206 0.205 0.206c Black liquor, % 0.134 0.143 0.160 Lignin I, % 0.027 0.027 0.021 Pulp, % 0.043 0.036 0.024 Fatty Acids 0.240 0.288 0.342 0.342d Black liquor, % 0.139 0.191 0.245 Lignin I, % 0.052 0.060 0.069 Pulp, % 0.049 0.037 0.028 a A l l values are percentages on O.D. wood basis. b Kappa number (K No) multiplied by 0.15 = Lignin (%). c These values were obtained by chemical analyses of the wood. This fatty acid content was determined a f t e r organosolv pulping. 159 P u l p y i e l d s a f t e r 20 m i n ( 7 1 % ) , 40 m i n (59%) a n d 60 m i n (54.5%) a r e c o m p a r a b l e w i t h t h o s e f o u n d b y B e h e r a a n d P a s z n e r ( 1 9 8 5 ) . The t o t a l l i g n i n c o n t e n t p r e s e n t i n s l a s h p i n e wood was 2 8 . 2 % . The l i g n i n r e c o v e r e d a f t e r p u l p i n g was d i r e c t l y q u a n t i f i e d g r a v i m e t r i c a l l y t h r o u g h p r e c i p i t a t i o n f r o m t h e b l a c k l i q u o r ( i . e . " L i g n i n I " , w h i c h p r e c i p i t a t e s on c o o l i n g o f t h e b l a c k l i q u o r , " L i g n i n S" t h a t r e m a i n s i n s o l u t i o n i n t h e b l a c k l i q u o r a f t e r f i l t r a t i o n o f L i g n i n I) a n d " L i g n i n P" ( w h i c h i s a l i g n i n c o - r e m o v e d d u r i n g t h e S o x h l e t m e t h a n o l r e m o v a l o f t h e e x t r a c t i v e s f r o m p u l p ) , o r i n d i r e c t l y a s c e r t a i n e d v o l u m e t r i c a l l y b y an o x i d a t i o n r e a c t i o n w i t h p o t a s s i u m p e r m a n g a n a t e (Kappa n u m b e r ) . The d e g r e e o f d e l i g n i f i c a t i o n o f t h e wood ( L i g n i n I p l u s L i g n i n S) a f t e r 20, 40 a n d 60 m i n c o o k i n g was a b o u t 4 2 . 5 % , 5 0 . 5 % a n d 5 8 .4%, r e s p e c t i v e l y . On r e m o v a l o f t h e e x t r a c t i v e s w i t h m e t h a n o l by S o x h l e t e x t r a c t i o n f r o m t h e o r g a n o s o l v p u l p s , some l i g n i n was c o - r e m o v e d w i t h t h e e x t r a c t i v e s a n d s u b s e q u e n t l y p r e c i p i t a t e d . The amount o f t h i s l i g n i n ( L i g n i n P) a f t e r t h e 20, 40 a n d 60 m i n c o o k s was 3.16%, 2.54% a n d 2.39%, r e s p e c t i v e l y . T h i s i n d i c a t e d t h a t w a s h i n g w i t h c o o k i n g l i q u o r r e m o v e d t h e f r e e l i g n i n i n c o m p l e t e l y f r o m t h e p u l p . I n a d d i t i o n t o t h e q u a n t i f i c a t i o n a n a l y s i s o f l i g n i n , a d d i t i o n a l w o r k was d e s i g n e d t o d e t e r m i n e t h e m o l e c u l a r 160 w e i g h t d i s t r i b u t i o n o f t h e d i f f e r e n t l i g n i n s o b t a i n e d a t t h e d i f f e r e n t p u l p i n g c o n d i t i o n s . 4.6.2. Molecular weight d i s t r i b u t i o n of l i g n i n M o l e c u l a r w e i g h t d i s t r i b u t i o n s o f t h e d i f f e r e n t l i g n i n t y p e s w e re d e t e r m i n e d b y s i z e e x c l u s i o n c h r o m a t o g r a p h y . A c a l i b r a t i o n c u r v e o b t a i n e d u s i n g p o l y s t y r e n e s t a n d a r d s i s g i v e n i n F i g . 2 2 . M o l e c u l a r w e i g h t d i s t r i b u t i o n s t u d i e s w e r e p e r f o r m e d on l i g n i n s o b t a i n e d f o r b o t h n o r m a l ( a u t o g e n i c ) p r e s s u r e a n d h i g h p r e s s u r e d u r i n g p u l p i n g . 4.6.2.1. MWD of l i g n i n s from normal pressure cooks A s e r i e s o f c o o k s was p e r f o r m e d a t n o r m a l p r e s s u r e , t h a t i s w i t h o u t p r e s s u r i z i n g t h e v e s s e l s p r i o r t o t h e i r i m m e r s i o n i n t o t h e h o t o i l b a t h . The a p p a r e n t w e i g h t a v e r a g e (M w) a n d t h e number a v e r a g e (M n) m o l e c u l a r w e i g h t v a l u e s w e r e c a l c u l a t e d f r o m t h e e l u t i o n p r o f i l e s a t c o n s t a n t a b s o r p t i v i t y 280 nm w a v e l e n g t h . The r e s u l t s a r e shown i n T a b l e 2 9 . 161 18.' 4J A 0» •H ffl 3 U (TJ H 3 CJ CD H O 2 10. 19. 4. 10. 10. 10 1. 51 J I I L 16. 9 22. 6 28. 31 34. 82 29. 73 45. 43 19.75 25.46 31.16 36. 87 42. 58 El u t i o n Volume (mL) Figure 22. GPC c a l i b r a t i o n curve with polystyrene standards 162 Table 29. Apparent Mw and Mn of l i g n i n s a f t e r normal pressure organosolv pulping Lignin Type: Mw Mn Mw/Mn D i s s o l v e d * 1474 631 2.34 P r e c i p i t a t e d * * 4218 1076 3.92 E n t r a p p e d * * * 5525 1134 4.87 F r o m t h i s t a b l e i t c a n be s e e n t h a t t h e " e n t r a p p e d l i g n i n " shows t h e h i g h e s t w e i g h t a v e r a g e m o l e c u l a r w e i g h t (Mw=5525). T h i s i n d i c a t e s a h i g h p r o p o r t i o n o f h i g h e r m o l e c u l a r w e i g h t l i g n i n m o l e c u l e s r e m a i n i n g i n t h e p u l p as " e n t r a p p e d l i g n i n " i n c o m p a r i s o n t o t h e o t h e r l i g n i n s . The p r o c e d u r e f o r c a l c u l a t i o n o f w e i g h t a v e r a g e m o l e c u l a r w e i g h t p l a c e s a g r e a t e r e m p h a s i s on t h e f r a c t i o n o f h i g h m o l e c u l a r w e i g h t m o l e c u l e s t h a n t h a t o f t h e number a v e r a g e m o l e c u l a r w e i g h t . The f r a c t i o n s o f " e n t r a p p e d l i g n i n " m o l e c u l e s w i t h m o l e c u l a r w e i g h t s i n t h e r a n g e o f 150,000 t o 50,000 a n d 50,000 t o 8,000, a r e 6% a n d 1 1 % , r e s p e c t i v e l y . T h e s e f r a c t i o n s a r e h i g h e r t h a n t h o s e g i v e n f o r t h e " p r e c i p i t a t e d l i g n i n " w i t h 1 0 % o f t h e l i g n i n m o l e c u l e s f a l l i n g i n t h e r a n g e o f 50,000 t o 8,000, a n d 0% * D i s s o l v e d l i g n i n , i s t h e l i g n i n t h a t r e m a i n s i n s o l u t i o n e v e n a f t e r t h e l i q u i d - l i q u i d e x t r a c t i o n o f t h e e x t r a c t i v e s f r o m t h e b l a c k l i q u o r . * * P r e c i p i t a t e d l i g n i n , i s t h e l i g n i n t h a t p r e c i p i t a t e s on c o o l i n g o f t h e " i n i t i a l b l a c k l i q u o r " . * * * E n t r a p p e d o r t r a p p e d l i g n i n , i s t h e f r e e l i g n i n l e f t i n t h e p u l p w h i c h i s r e m o v e d f r o m i t b y s u c c e s s i v e a c e t o n e -w a t e r - a c e t o n e w a s h i n g s a n d p r e c i p i t a t e s f r o m t h i s s o l u t i o n . 163 f o r t h e " d i s s o l v e d l i g n i n " w h i c h d o e s n o t show m o l e c u l e s w i t h Mw h i g h e r t h a n 1 0,000. (See T a b l e 30 a n d F i g . 23 a n d 24) . On t h e o t h e r h a n d , t h e " d i s s o l v e d l i g n i n " shows t h e l o w e s t Mn v a l u e (Mn=631). T h i s r e f l e c t s a h i g h p r o p o r t i o n o f l o w m o l e c u l a r w e i g h t ( d i m e r s , t r i m e r s a n d t e t r a m e r s ) l i g n i n f r a g m e n t s i n t h e s o l u b l e l i g n i n . A l m o s t 4 5 % o f t h e s o l u b l e l i g n i n m o l e c u l e s f a l l i n t h e r a n g e o f m o l e c u l a r w e i g h t b e l o w 1000. However, t h e p r e c i p i t a t e d a n d e n t r a p p e d l i g n i n s c o n t a i n o n l y 2 2 % e a c h o f l o w m o l e c u l a r w e i g h t p r o d u c t . A c o m p a r i s o n o f t h e m o l e c u l a r w e i g h t d i s t r i b u t i o n o f t h e s e t h r e e ( d i s s o l v e d , p r e c i p i t a t e d a n d e n t r a p p e d ) l i g n i n s i s p r e s e n t e d i n F i g . 2 5 . An i n t e r e s t i n g o b s e r v a t i o n i s t h a t f a i r l y w e l l s e p a r a t e d p e a k s a r e o b s e r v e d i n t h e c h r o m a t o g r a m s f o r e a c h l i g n i n f r a c t i o n a t m o l e c u l a r w e i g h t l o w e r t h a n 400. The m ost p r o m i n e n t l o w m o l e c u l a r w e i g h t p e a k i s o b s e r v e d i n t h e d i s s o l v e d l i g n i n c h r o m a t o g r a m a n d i n d i c a t e s t h e p r e s e n c e o f m o n o m e r i c c o m p o n e n t s ( m o l e c u l a r w e i g h t 160 t o 1 9 0 ) . A s s u m p t i o n s f o r s t r u c t u r e s a t h i g h e r m o l e c u l a r w e i g h t s a r e l e s s f e a s i b l e due t o t h e l a r g e number o f c o n d e n s a t i o n p a t h w a y s by w h i c h t h e p h e n y l - p r o p a n e u n i t s m i g h t be j o i n e d t o f o r m e i t h e r d i m e r s , t r i m e r s , t e t r a m e r s , e t c . T h e s e may be more p r o f i t a b l y s t u d i e d b y s o l i d s t a t e NMR. Table 30. Molecular weight d i s t r i b u t i o n ranges of the d i f f e r e n t l i g n i n fractions obtained with normal (autogenous) pressure cooks Molecular Weight Ranges Lignin 150000-50000 50000-8000 8000-5000 5000-1000 1000-200 < 200 Type % % % % % % Dissolved 0 0 3 52 38 7 Precipitated 0 10 12 56 20 2 Entrapped 6 11 16 51 20 2 Figure 23. Molecular weight d i s t r i b u t i o n curves of l i g n i n s i s o l a t e d a f t e r normal pressure organosolv pulping of slas h pine 166 Figure 24. Molecular weight d i s t r i b u t i o n curve of the dissolved l i g n i n i s o l a t e d a f t e r normal pressure organosolv pulping of slash pine 167 D i s s ol V e d L ig n i r Pr e c i pi t< ted L i< i i n T r a P P e d L g n i n 1 ' i i i i i ,; i , i i i i i i i | i i i i i i i i , ^ T - i i I I I . " 100 1000 10000 100000 1000001 Molecular Weight Figure 25. Molecular weight d i s t r i b u t i o n of the soluble l i g n i n s (Dissolved, p r e c i p i t a t e d and trapped l i g n i n s ) i s o l a t e d from normal organosolv pulping of slash pine 168 4.6.2.2. MWD of lignin from high pressure cooks A s m e n t i o n e d i n S e c t i o n 4.5.1.1., t h e 5 m i n u t e c o o k d i d n o t r e s u l t i n f i b e r l i b e r a t i o n , b u t c a u s e d r e m o v a l o f e x t r a c t i v e s a n d some l i g n i n . On c o o l i n g o f t h e b l a c k l i q u o r , a s m a l l amount o f " L i g n i n I " p r e c i p i t a t e d a n d s e p a r a t e d , a n d o n l y t h e s o l u b l e l i g n i n ( L i g n i n S-5) was t a k e n f o r GPC a n a l y s i s . A m o l e c u l a r w e i g h t d i s t r i b u t i o n o f " L i g n i n S-5" i s p r e s e n t e d i n F i g . 2 6 a . 4.6.2.2.1. Soluble lignins in the black liquor A f t e r t h e 20, 40 a n d 60 m i n c o o k i n g a t h i g h p r e s s u r e , r e a d y f i b e r l i b e r a t i o n t o o k p l a c e . The l i g n i n s , w h i c h p r e c i p i t a t e d on c o o l i n g ( " L i g n i n I") f r o m t h e r e s p e c t i v e b l a c k l i q u o r s , w e r e i s o l a t e d o n l y f o r q u a n t i t a t i v e a n a l y s i s . T h e i r r e s p e c t i v e s o l u b l e l i g n i n s ( L i g n i n s S-20, S-40 a n d S-60) were t a k e n f o r GPC a n a l y s i s . The r e s p e c t i v e m o l e c u l a r w e i g h t d i s t r i b u t i o n c u r v e s a r e shown i n F i g . 26 a n d 27, a n d a c o m p a r i s o n o f t h e i r m o l e c u l a r w e i g h t d i s t r i b u t i o n s i s g i v e n i n F i g . 2 8. L o o k i n g a t t h e d i s t r i b u t i o n c u r v e s o f t h e s e s o l u b l e l i g n i n s , a d i s c e r n i b l e s h i f t o f t h e s e c u r v e s t o w a r d t h e l o w e r m o l e c u l a r w e i g h t r e g i o n c a n be s e e n a s t h e c o o k i n g t i m e s a r e e x t e n d e d ( T a b l e 3 2 ) . T h i s c a n be e x p l a i n e d 169 "b" o _J Figure 26. D i s t r i b u t i o n curves of the soluble l i g n i n s i s o l a t e d a f t e r a high pressure organosolv pulping of slash pine: a) S-5 l i g n i n b) S-20 l i g n i n 170 E " a " 3 o "b II £ CJ > 3 <s in r-i Figure 27 D i s t r i b u t i o n curves of the soluble l i g n i n s i s o l a t e d a f t e r a high pressure organosolv pulping of slash pine: a) S-40 b) S-60 171 J 1 V h S - 5 S - 20 1 S - 40 S - 6C > I I I I I ! I I | I I I I I I I I | I I I I I I I I | I 1 1 1—I—I I > | 100 1000 10000 100000 1000000 Molecular Weight Figure 28. Molecular weight d i s t r i b u t i o n of the soluble l i g n i n s (S-5, S-20, S-40 and S-60) i s o l a t e d from high pressure organosolv pulping of slash pine 172 i n t e r m s o f d e g r a d a t i o n o f t h e h i g h e r m o l e c u l a r w e i g h t l i g n i n m o l e c u l e s i n t o l o w e r m o l e c u l a r w e i g h t f r a g m e n t s . The same d e g r a d a t i o n t r e n d i s a l s o e v i d e n t on l o o k i n g a t t h e d e c r e a s e o f t h e w e i g h t a v e r a g e m o l e c u l a r w e i g h t o f t h e s e f r a c t i o n s a n d t h e i n c r e a s e o f t h e number a v e r a g e m o l e c u l a r w e i g h t , a s t h e c o o k i n g t i m e s a r e p r o l o n g e d . N u m e r i c a l m o l e c u l a r w e i g h t v a l u e s a r e p r e s e n t e d i n T a b l e 3 1 . Table 31. Apparent Mw and Mn of the soluble lignins after the 5, 20, 40 and 60 min organosolv pulping of slash pine wood Mw/Mn Cooking time Mw Mn 5 m i n 1041 407 2.6 20 m i n 1390 678 2.1 4 0 m i n 1211 685 1.8 60 m i n 988 618 1.6 The d e c r e a s i n g p o l y d i s p e r s i t y n u mbers d e m o n s t r a t e t h a t t h e d e g r a d a t i o n o f l i g n i n i s c o n t i n u e d b y e x t e n d i n g t h e c o o k i n g t i m e u n d e r t h e p r e s e n t c o n d i t i o n s . However, c o n t r a d i c t o r y r e s u l t s h a v e b e e n r e p o r t e d b y Kondo a n d M c C a r t y (1985) on k r a f t p u l p i n g o f w e s t e r n h e m l o c k wood [Tsuga heterophylla ( R a f . ) S a r g . ] . They r e p o r t e d t h a t i n i n c r e m e n t a l d e l i g n i f i c a t i o n o f h e m l o c k wood, t h e l a t t e r 173 i n c r e m e n t s show much i n c r e a s e d p r o p o r t i o n s o f h i g h e r m o l e c u l a r w e i g h t l i g n i n s . Kondo a n d M c C a r t y (1985) c o n c l u d e d t h a t t h e f o r m a t i o n o f h i g h e r m o l e c u l a r w e i g h t l i g n i n m o l e c u l e s was l i k e l y due t o r e c o n d e n s a t i o n r e a c t i o n s . H a g s t r o m - N a s i a n d S j o s t r o m (1988) w o r k i n g w i t h d i o x a n e l i g n i n a n d o x i d i z i n g i t u n d e r a l k a l i n e c o n d i t i o n s , f o u n d t h a t b y i n c r e a s i n g t h e c o n c e n t r a t i o n o f e t h a n o l f r o m 0, 20, 50 a n d 80%, d e g r a d a t i o n o f l i g n i n was a c c e l e r a t e d . C l a r e a n d S t e e l i n k (1973) a n d K a t u s c a k e t al. (1971) m e n t i o n t h a t d u r i n g t h e o x i d a t i o n o f l i g n i n u n d e r e t h a n o l i c c o n d i t i o n s i t i s v e r y l i k e l y t h a t t h e e t h a n o l s o l v e n t r e t a r d e d r e p o l i m e r i z a t i o n r e a c t i o n s . H a g s t r o m - N a s i a n d S j o s t r o m (1988) i n o r d e r t o c l a r i f y t h i s p o s s i b i l i t y , p e r f o r m e d an a l k a l i n e o x y g e n o x i d a t i o n o f c r e o s o l a t v a r i o u s e t h a n o l c o n c e n t r a t i o n s . C r e o s o l was u s e d a s a m o d e l compound w h i c h i s known t o u n d e r g o c o u p l i n g r e a c t i o n s d u r i n g a l k a l i n e a u t o x i d a t i o n ( K r a t z l , 1966; K r a t z l , 1 9 7 4 ) . H a g s t r o m - N a s i a n d S j o s t r o m (1988) f o u n d t h a t c r e o s o l was s t a b i l i z e d b y e t h a n o l t o w a r d t h e a l k a l i n e o x y g e n o x i d a t i o n a s e t h a n o l c o n c e n t r a t i o n was i n c r e a s e d . They e x p l a i n e d t h i s phenomena a s a r e s u l t o f c o u p l i n g r e a c t i o n s o f r a d i c a l s f r o m e t h a n o l w i t h p h e n o x y r a d i c a l s , c a u s i n g a d e c r e a s e i n t h e g e n e r a t i o n o f d i m e r s . C o n s e q u e n t l y , i n h i b i t i o n o f r e p o l y m e r i z a t i o n o f t h e l i g n i n f r a g m e n t s c a n be e x p l a i n e d i n t e r m s o f t h e r e t a r d a n t 174 e f f e c t of the s o l v e n t (ethanol) towards the o x i d a t i v e c o u p l i n g r e a c t i o n s . T h e r e f o r e , i t i s p o s s i b l e t o i n f e r t h a t working with very h i g h methanol c o n c e n t r a t i o n s ( i . e . 80%, Paszner and Cho, 1989) and e l e v a t e d p r e s s u r e s (Chang and Paszner, 1982), l i g n i n i s degraded e x t e n s i v e l y (Mw=988, at 60 min) and i s i n h i b i t e d from recondensation r e a c t i o n s . These f i n d i n g s can be w e l l supported by the data g i v e n i n Tables 31 and i n Table 32 and emphasized by Paszner and Cho (1989) as advantages of the N7AEM c a t a l y z e d organosolv p r o c e s s . 4.6.2.2.2. Complementary analyses of l i g n i n a f t e r a h i g h pressure 60 min pulping Complementary l i g n i n analyses were performed a f t e r a h i g h p r e s s u r e , 60 min cook. Contrary t o the f r a c t i o n a t i o n procedure f o l l o w e d f o r the e x t r a c t i v e analyses a f t e r the 5, 20, 40 and 60 min cooks, e x t e n s i v e d i l u t i o n of the mother b l a c k l i q u o r with water (1:10 r a t i o ) rendered another type of l i g n i n ("Lignin II") by p r e c i p i t a t i n g the b u l k of the d i s s o l v e d l i g n i n ( L i g n i n S p l u s L i g n i n I) . T h i s " L i g n i n I I" was i s o l a t e d and d r i e d as d e s c r i b e d i n S e c t i o n 3.6.2.1. The molecular weight d i s t r i b u t i o n of t h i s Table 32. Percentage of the molecular weight ranges of the d i f f e r e n t soluble l i g n i n s fractions from high pressure organosolv cooks of slash pine wood M o l e c u l a r w e i g h t , M, w L i g n i n t y p e 8000 - 5000 % 5000 - 1000 % 1000 - 200 % < 200 % s s s s 5 20 40 60 0.5 2.0 1.0 0.5 24.5 48.0 46.0 42.5 72.0 47.5 51.0 55.5 3.0 2.5 2.0 2.0 176 l i g n i n was d e t e r m i n e d b y s i z e e x c l u s i o n c h r o m a t o g r a p h y w i t h t h e a i d o f an HPLC. (See F i g . 2 9 a ) . A f t e r S o x h l e t r e m o v a l o f t h e e x t r a c t i v e s f r o m t h e p u l p w i t h m e t h a n o l a s t h e s o l v e n t , a n o t h e r f r a c t i o n o f l i g n i n ( " L i g n i n P") was c o - e x t r a c t e d a n d u s e d f o r GPC a n a l y s i s (See F i g . 29b) . T h i s l i g n i n was c o m p a r e d w i t h " L i g n i n I I " a n d " L i g n i n S - 6 0 " , a l l o r i g i n a l l y f r o m t h e same 60 m i n c o o k . The m o l e c u l a r w e i g h t d i s t r i b u t i o n s o f t h e s e t h r e e l i g n i n s a r e c o m p a r e d i n F i g . 30 a n d t h e i r a p p a r e n t Mw a n d Mn a r e g i v e n i n T a b l e 3 3 . Table 33. Apparent Mw and Mn of Lignin II, Lignin P and Lignin S-60 after the 60 min cooking Mw Mn Mw/Mn L i g n i n I I 4395 759 5.8 L i g n i n P 23999 2019 11.9 L i g n i n S-60 988 618 1.6 From t h e s e d a t a , i t c a n be s e e n t h a t " L i g n i n P" h a s an u n u s u a l l y h i g h p o l y d i s p e r s i v i t y number a n d w e i g h t a v e r a g e m o l e c u l a r w e i g h t , w h i l e " L i g n i n S-60" h a s b o t h t h e l o w e s t p o l y d i s p e r s i v i t y number a n d number a v e r a g e m o l e c u l a r w e i g h t . T r a p p e d l i g n i n f r a g m e n t s i n t h e il <£> in r-i cO a *n ,© © © CD © CD CD © Figure 29. D i s t r i b u t i o n curves of the l i g n i n s i s o l a t e d during the complementary analysis a f t e r a 60 min high pressure organosolv pulping of slash pine: a) Lignin-II-60 b) Lignin-P 178 LIGNIN II LIGNIN P Figure 30. Molecular weight d i s t r i b u t i o n of "Lignin I I " , "Lignin P" and "Lignin S-60" a f t e r the 60 min cooking of slash pine 179 s e c o n d a r y w a l l r e q u i r e f u r t h e r d e g r a d a t i o n b e f o r e t h e y c a n e s c a p e b y d i f f u s i o n i n t o t h e c o o k i n g l i q u o r . Thus l i m i t e d s o l v e n t a c c e s s i b i l i t y i n t h e c e l l w a l l may p a r t l y be r e s p o n s i b l e f o r t h e r e l a t i v e l y l a r g e amount o f h i g h m o l e c u l a r w e i g h t r e s i d u a l l i g n i n i n o r g a n o s o l v p u l p s . Due t o t h e f a c t t h a t " L i g n i n P" was c o - e x t r a c t e d t o g e t h e r w i t h t h e e x t r a c t i v e s d u r i n g t h e S o x h l e t e x t r a c t i o n o f t h e p u l p , i t was f i r s t s u s p e c t e d t h a t t h i s l i g n i n m i g h t u n d e r g o r e c o n d e n s a t i o n b e c a u s e o f t h e l o n g r e f l u x i n g p r o c e s s (54 h) r e q u i r e d f o r r e m o v a l o f t h e e x t r a c t i v e s . I n o r d e r t o e l u c i d a t e t h i s i n t r i g u i n g r e s u l t , 300 mg o f a l o w m o l e c u l a r w e i g h t l i g n i n ( " L i g n i n S-20, Mw= 1390 a n d M n= 678) was r e f l u x e d i n m e t h a n o l f o r 54 h. The w e i g h t a n d number a v e r a g e m o l e c u l a r w e i g h t s o b t a i n e d a f t e r t h i s t r e a t m e n t w e r e t h e same a s t h e t h e o r i g i n a l v a l u e s . T h i s c o n f i r m s t h a t r e f l u x i n g i n m e t h a n o l d i d n o t p r o v o k e r e c o n d e n s a t i o n o f t h e o r g a n o s o l v l i g n i n , a n d t h e r e f o r e t h e i n i t i a l h i g h m o l e c u l a r w e i g h t s o f p u l p r e s i d u a l l i g n i n a r e i n d e e d v a l i d . 180 5. SUMMARY The b e h a v i o u r o f t h e e x t r a c t i v e s p r e s e n t i n s l a s h p i n e wood (Pinus e l l i o t t i i ) d u r i n g p u l p i n g u s i n g c a t a l y z e d 80% a q u e o u s m e t h a n o l , was s t u d i e d i n d e t a i l . R e s i n - a n d f a t t y a c i d s were c h a r a c t e r i z e d b e f o r e a n d a f t e r t h e p u l p i n g t r i a l s . T o t a l wood e x t r a c t i v e s were d e t e r m i n e d g r a v i m e t r i c a l l y b y m e t h a n o l i c c o l d m a c e r a t i o n a n d S o x h l e t e x t r a c t i o n , a n d by t h e T A P P I s t a n d a r d T 204 o s - 7 6 . No s i g n i f i c a n t d i f f e r e n c e s were f o u n d b e t w e e n t h e e f f i c i e n c i e s o f t h e s e t h r e e t y p e s o f e x t r a c t i o n s . The r e s i n - a n d f a t t y a c i d s t h u s c o l l e c t e d were s a p o n i f i e d a n d / o r m e t h y l a t e d a n d c h a r a c t e r i z e d b y g a s l i q u i d c h r o m a t o g r a p h y (GC o r GLC) a n d g a s c h r o m a t o g r a p h y -mass s p e c t r o m e t r y . P u l p i n g e x p e r i m e n t s w e re p e r f o r m e d a t 2 0 5 2 C f o r p e r i o d s o f 5, 20, 40 a n d 60 m i n . C h e m i c a l c h a r a c t e r i z a t i o n o f t h e r e s i n a n d f a t t y a c i d e x t r a c t i v e s r e v e a l e d o n l y m i n o r q u a l i t a t i v e c h a n g e s i n t h e f o r m o f l i m i t e d i s o m e r i z a t i o n s o f c e r t a i n c o m p o n e n t s . R e s i n - a n d f a t t y a c i d s s u r v i v i n g t h e h i g h t e m p e r a t u r e p u l p i n g p r o c e s s , were f o u n d m a i n l y i n t h e b l a c k l i q u o r . The e x t r a c t i v e s w e r e r e c o v e r e d f r o m t h e c o o k i n g l i q u o r by a s e l e c t i v e t e r t i a r y component l i q u i d / l i q u i d e x t r a c t i o n p r o c e d u r e . The w a t e r / m e t h a n o l r a t i o o f t h e b l a c k l i q u o r was a d j u s t e d p r i o r t o e x t r a c t i o n w i t h d i e t h y l e t h e r 181 a c c o r d i n g t o a p h a s e d i a g r a m d e v e l o p e d f o r t h i s p u r p o s e . The l i q u i d / l i q u i d e x t r a c t i o n was n e a r l y 1 0 0 % e f f e c t i v e i n r e m o v i n g t h e e x t r a c t i v e s f r o m t h e b l a c k l i q u o r . I n t h e c o o k i n g l i q u o r , s u b s t a n t i a l q u a n t i t i e s o f r e s i n a c i d s (89.8%) a n d f a t t y a c i d s (25.6%) w e r e d e t e c t e d a f t e r 5 m i n c o o k i n g ( l e s s t h a n t h e a c t u a l t i m e t o t e m p e r a t u r e ) . A f t e r a 60 m i n c o o k t h e b l a c k l i q u o r c o n t a i n e d 7 8 . 1 % a n d 7 1 . 6 % r e s i n - a n d f a t t y a c i d s , r e s p e c t i v e l y , w h i l e t h e p u l p r e t a i n e d 1 1 . 7 % a n d 8.2%, r e s p e c t i v e l y . E f f e c t i v e e x t r a c t i v e s r e m o v a l f r o m t h e b l a c k l i q u o r was o b s e r v e d on p r e c i p i t a t i o n o f t h e l i g n i n ( L i g n i n I I ) by d i l u t i o n w i t h 10 t i m e s v o l u m e o f w a t e r . L i g n i n I I c a r r i e d 9 8% a n d 60.4% o f r e s i n - a n d f a t t y a c i d s ( r e s p e c t i v e l y ) l e a v i n g m i n o r amounts o f r e s i n a c i d s (2%) a n d some f a t t y a c i d s (39.6%) d i s s o l v e d i n t h e a q u e o u s f i l t r a t e . A s m a l l f r a c t i o n o f l i g n i n w h i c h p r e c i p i t a t e s on c o o l i n g o f t h e b l a c k l i q u o r ( " L i g n i n I") a d s o r b e d a n d c a r r i e d 1 0 . 2 % a n d 2 0 . 2 % o f t h e r e s i n - a n d f a t t y a c i d s , r e s p e c t i v e l y . I t i s , t h e r e b y , d e m o n s t r a t e d t h a t o u t r i g h t l i g n i n p r e c i p i t a t i o n f r o m o r g a n o s o l v b l a c k l i q u o r u s u a l l y y i e l d l i g n i n p o w d e r s s u b s t a n t i a l l y c o n t a m i n a t e d w i t h e x t r a c t i v e s a n d t h e a q u e o u s f i l t r a t e s t i l l c o n t a i n s e x t r a c t i v e s r e s i d u e s w h i c h may be t o x i c t o f e r m e n t i n g o r g a n i s m s . The r e s i d u a l e x t r a c t i v e s i n t h e a q u e o u s f i l t r a t e a f t e r p r e c i p i t a t i n g t h e l i g n i n d i d n o t show s t r u c t u r a l d i f f e r e n c e s f r o m t h e 182 c o m p o n e n t s n o r m a l l y r e m o v e d w i t h t h e p r e c i p i t a t e d l i g n i n a n d t h u s e x t r a c t i v e s r e m o v a l f r o m t h e b l a c k l i q u o r b y l i g n i n p r e c i p i t a t i o n may d e p e n d on t h e e x t r a c t i v e b i n d i n g c a p a c i t y o f t h e l i g n i n o r l i m i t e d b y c o n c e n t r a t i o n ( s o l u b i l i t y ) i n t h e a q u e o u s f i l t r a t e . D i f f e r e n t l i g n i n s w e r e o b t a i n e d f r o m t h e b l a c k l i q u o r a n d p u l p , b a s e d on t h e i r s o l u b i l i t y . A l i g n i n f r a c t i o n w h i c h p r e c i p i t a t e s on c o o l i n g o f t h e b l a c k l i q u o r was d e s i g n a t e d " L i g n i n I " , t h e l i g n i n t h a t r e m a i n s i n s o l u t i o n was named " L i g n i n S" a n d t h e l i g n i n t h a t r e q u i r e d f u r t h e r e x t r a c t i o n f r o m t h e p u l p was c a l l e d " L i g n i n P". T h e i r m o l e c u l a r w e i g h t d i s t r i b u t i o n s w e r e d e t e r m i n e d b y s i z e e x c l u s i o n c h r o m a t o g r a p h y on an HPLC. Q u a n t i f i c a t i o n o f t h e s e l i g n i n s i n v o l v e d b o t h g r a v i m e t r i c a n d v o l u m e t r i c m e t h o d s . 183 6. CONCLUSIONS R e m o v a l o f t h e wood e x t r a c t i v e s was n o t a f f e c t e d by h e a t , s i n c e e x t r a c t i o n b y b o t h c o l d m e t h a n o l m a c e r a t i o n a n d S o x h l e t m e t h a n o l e x t r a c t i o n g a v e t h e same q u a l i t a t i v e a n d q u a n t i t a t i v e r e s u l t s . E f f i c i e n c i e s o f t h e c o l d m e t h a n o l m a c e r a t i o n , m e t h a n o l S o x h l e t e x t r a c t i o n a n d t h e T A P P I e x t r a c t i o n o f t h e wood e x t r a c t i v e s f r o m s l a s h p i n e w e re v e r y s i m i l a r . Q u a n t i t a t i v e r e s u l t s o f t h e s l a s h p i n e wood e x t r a c t i v e s a f t e r 6 weeks o f s t o r a g e w e re a l m o s t t h e same by t h e t h r e e m e t h o d s u s e d : c o l d m e t h a n o l m a c e r a t i o n ( 4 . 2 % ) , m e t h a n o l S o x h l e t e x t r a c t i o n (4.3%) a n d t h e T APPI s t a n d a r d T 204 o s - 7 6 ( 3 . 9 % ) . M e t h y l a t i o n o f t h e r e s i n - a n d f a t t y a c i d s d i s s o l v e d i n d i c h l o r o m e t h a n e - m e t h a n o l (9:1) was f a s t e r a n d more c o m p l e t e t h a n i n d i e t h y l e t h e r - m e t h a n o l (9:1) o r m e t h a n o l a l o n e . M e t h y l a t i o n o f t h e r e s i n - a n d f a t t y a c i d s p r e s e n t i n t h e c o l o r e d wood e x t r a c t s s o l u t i o n s was f o u n d t o be c o m p l e t e a f t e r b u b b l i n g f r e s h l y p r e p a r e d d i a z o m e t h a n e f o r a b o u t 4 m i n . D e t e r m i n a t i o n s o f t h e r e s i n - a n d f a t t y a c i d s (RAFA) f r o m wood, p u l p i n g l i q u o r a n d p u l p w e re p e r f o r m e d w i t h o u t f r a c t i o n a t i o n o f t h e e x t r a c t s b e f o r e t h e g a s c h r o m a t o g r a p h i c a n a l y s i s . Good r e s o l u t i o n o f t h e s e 184 compounds was due t o t h e p r o p e r t e m p e r a t u r e p r o g r a m m i n g a n d c h a r a c t e r i s t i c s o f t h e c o l u m n s u s e d . 7. The HP-5 c a p i l l a r y c o l u m n was a b l e t o c l e a r l y r e s o l v e p i m a r i c , s a n d a r a c o p i m a r i c , i s o p i m a r i c , p a l u s t r i c , d e h y d r o a b i e t i c , a b i e t i c a n d n e o a b i e t i c a c i d s . However, i t d i d n o t s e p a r a t e t h e p a i r l e v o p i m a r i c - p a l u s t r i c a c i d s . Among t h e f a t t y a c i d s o f t h e s t u d y o n l y p a l m i t i c a n d s t e a r i c a c i d s w e re r e s o l v e d on t h i s c o l u m n . 8. The DB-225 megabore c o l u m n r e s o l v e d p a l m i t i c , s t e a r i c , o l e i c , l i n o l e i c a n d l i n o l e n i c a c i d s p r o p e r l y . D i r e c t a n a l y s i s o f t h e r e s i n - a n d f a t t y a c i d s w i t h o u t s e p a r a t i o n f r o m t h e o t h e r wood e x t r a c t i v e s , was due t o t h e e x c e l l e n t c h a r a c t e r i s t i c s o f t h e c a p i l l a r y c o l u m n s ( f u s e d - s i l i c a c r o s s - l i n k e d b o n d e d p h a s e ) a n d t o t h e a p p r o p r i a t e t i m e p r o g r a m m i n g f o r t h e GC a n a l y s i s . 9. The t o t a l c o n t e n t o f t h e 7 m a j o r r e s i n a c i d s p r e s e n t i n s l a s h p i n e wood a f t e r 6 weeks o f s t o r a g e (1.040%) was n o t a b l y r e d u c e d a f t e r 24 weeks o f s t o r a g e (0.206%) . C o m p a r i s o n o f t h e mass f r a g m e n t a t i o n p a t t e r n s o f p a l u s t r i c a c i d , l e v o p i m a r i c a c i d a n d t h e i r c o r r e s p o n d i n g p e a k s i n t h e wood e x t r a c t c h r o m a t o g r a m s , r e v e a l e d t h a t l e v o p i m a r i c a c i d i s n o t p r e s e n t i n t h e m e t h a n o l i c e x t r a c t o f t h e wood s a m p l e a f t e r 6 weeks o f s t o r a g e . However, t h e p o s s i b i l i t y c o u l d e x i s t t h a t i t 185 m i g h t be p r e s e n t i n f r e s h wood a n d t h a t i t m i g h t h a v e d i s a p p e a r e d d u r i n g s t o r a g e . 10. The t o t a l c o n t e n t (1.389%) o f t h e 5 m a j o r f a t t y a c i d s p r e s e n t i n s l a s h p i n e wood a f t e r 6 weeks o f s t o r a g e was g r e a t l y r e d u c e d a f t e r 24 weeks o f s t o r a g e ( 0 . 3 1 6 % ) . 1 1 . R e l a t i v e p r o p o r t i o n s o f t h e r e s i n a c i d s a f t e r 6, 24 a n d 52 weeks o f s t o r a g e show t h a t a f t e r l o n g p e r i o d s o f s t o r a g e , d e h y d r o a b i e t i c a c i d i s t h e most s t a b l e f o r m among t h e r e s i n a c i d s . 12. S e l e c t i v e r e m o v a l o f t h e e x t r a c t i v e s f r o m t h e b l a c k l i q u o r ( m e t h a n o l - w a t e r a t 80:20 r a t i o ) was a c c o m p l i s h e d u s i n g l i q u i d - l i q u i d e x t r a c t i o n w i t h a d d e d d i e t h y l e t h e r . The t e r n a r y s o l v e n t s y s t e m t h a t g a v e g o o d s o l v e n t s e p a r a t i o n ( d i e t h y l e t h e r a n d w a t e r -m e t h a n o l ) h a d t h e f o l l o w i n g f i n a l p r o p o r t i o n s : M e t h a n o l - w a t e r - e t h e r ( 4 0 : 5 0 : 5 0 ) . 13. M o s t o f t h e e x t r a c t i v e s r e m o v e d f r o m t h e wood a f t e r t h e 60 m i n p u l p i n g were f o u n d i n t h e b l a c k l i q u o r (RA= 0.160% a n d FA= 0.245%) a n d p r e c i p i t a t e d l i g n i n (RA=0.021% a n d FA=0.0 6 9 % ) . Some r e s i d u a l r e s i n - a n d f a t t y a c i d s w e re l e f t i n t h e p u l p (RA=0.024% a n d FA=0.028%) . 14. O r g a n o s o l v p u l p i n g o f f a t t y a c i d m o d e l compounds d e m o n s t r a t e d t h a t t h e i r s u r v i v a l was c l o s e l y r e l a t e d t o t h e i r c h e m i c a l s t r u c t u r e s . S t e a r i c a c i d d i d n o t 186 s u f f e r any c h e m i c a l c h a n g e a f t e r o r g a n o s o l v p u l p i n g . On t h e o t h e r h a n d , o l e i c a n d l i n o l e i c a c i d s were r e d u c e d f r o m t h e i r o r i g i n a l c o n t e n t s b y a s much a s 20 a n d 90%, w h i l e l i n o l e n i c a c i d was c o m p l e t e l y d e g r a d e d d u r i n g p u l p i n g . The more u n s a t u r a t e d t h e a c i d , t h e more v u l n e r a b l e i t was t o d e s t r u c t i o n . 15. The t o t a l r e s i n a c i d c o n t e n t d o e s n o t s u f f e r q u a n t i t a t i v e c h a n g e s a f t e r o r g a n o s o l v p u l p i n g , b u t i n s t e a d q u a l i t a t i v e m o d i f i c a t i o n s o c c u r a s a r e s u l t o f e i t h e r i s o m e r i z a t i o n a n d / o r o x i d a t i o n r e a c t i o n s . 16. M o d e l compounds f o r p a l u s t r i c a n d l e v o p i m a r i c a c i d s d u r i n g o r g a n o s o l v p u l p i n g (60 m i n a t 2 0 5 2 C ) a r e a l m o s t c o m p l e t e l y i s o m e r i z e d i n t o d e h y d r o a b i e t i c a c i d . 17. M e t h y l n e o a b i e t a t e m o d e l compound i s c o m p l e t e l y d e s t r o y e d ( d i s a p p e a r s ) a f t e r o r g a n o s o l v p u l p i n g . 18. O r g a n o s o l v p u l p i n g o f i s o p i m a r i c a c i d ( m o d e l compound) r e n d e r s i s o p i m a r i c a c i d ( 8 8 % ) , p i m a r i c a c i d ( 1 . 8 % ) , s a n d a r a c o p i m a r i c a c i d (1.4%), d e h y d r o a b i e t i c a c i d (3.8%) a n d 5.0% o f o t h e r n o n - i d e n t i f i e d compounds. 19. M o d e l compounds o f p i m a r i c , s a n d a r a c o p i m a r i c a n d d e h y d r o a b i e t i c a c i d s do n o t s u f f e r a n y c h e m i c a l c h a n g e d u r i n g o r g a n o s o l v p u l p i n g a t 2 0 5 2 d u r i n g 60 m i n . 20 . I s o m e r i z a t i o n o r o x i d a t i o n r e a c t i o n s o f t h e r e s i n a c i d s d u r i n g s t o r a g e o f wood s a m p l e s , l e a d t o f o r m a t i o n o f d e h y d r o a b i e t i c a c i d , w h i l e d u r i n g 187 o r g a n o s o l v p u l p i n g a b i e t i c a n d d e h y d r o a b i e t i c a c i d s a r e t h e p r e f e r r e d e n d p r o d u c t s . 2 1 . The a v e r a g e f a t t y a c i d c o n t e n t o f wood s a m p l e s s t o r e d f o r 24 weeks ( s a m p l e s u s e d f o r p u l p i n g ) was 0.316%, a n d a f t e r 60 m i n o f o r g a n o s o l v p u l p i n g a l l (0.342%) f a t t y a c i d s w e r e r e m o v e d . T h i s i n c r e m e n t c a n be t h e r e s u l t o f b e t t e r h y d r o l y s i s ( s o l v o l y s i s ) o f t h e f a t m a t e r i a l a t h i g h t e m p e r a t u r e o r t h e e n d r e s u l t o f i s o m e r i z a t i o n r e a c t i o n s o f u n i d e n t i f i e d f a t t y a c i d s i n t o t h e f i v e m a j o r f a t t y a c i d s s t u d i e d . 2 2 . Q u a n t i t a t i v e a n a l y s i s o f l i g n i n i n s l a s h p i n e wood g i v e s an i n s o l u b l e - l i g n i n c o n t e n t o f 2 6 . 8 % a n d a s o l u b l e - l i g n i n c o n t e n t o f 1.4%. T h e r e f o r e , i t s t o t a l l i g n i n c o n t e n t was 2 8 . 2 % . 2 3 . E x t e n s i v e d i l u t i o n o f t h e p u l p i n g b l a c k l i q u o r w i t h w a t e r (1:10 r a t i o ) r e n d e r e d a p r e c i p i t a t e d l i g n i n ( " L i g n i n I I " ) w h i c h a d s o r b e d 98% o f t h e r e s i n a c i d s a n d 60% o f t h e f a t t y a c i d s , l e a v i n g t h e r e s i d u a l r e s i n - a n d f a t t y a c i d s d i s s o l v e d i n t h e a q u e o u s p h a s e . 24. GPC a n a l y s e s o f t h e p r e c i p i t a t e d s o l u b l e l i g n i n ( " L i g n i n S - 5 " ) , o b t a i n e d f r o m a 5 m i n c o o k , showed t h e p r e s e n c e o f a h i g h p r o p o r t i o n (75%) o f l o w m o l e c u l a r w e i g h t l i g n i n ( l e s s t h a n 1 0 0 0 ) . 2 5 . GPC a n a l y s e s o f t h e s o l u b l e l i g n i n s a f t e r t h e 20, 40 a n d 60 m i n c o o k s show t h a t t h e w e i g h t a v e r a g e m o l e c u l a r w e i g h t (Mw) d e c r e a s e s a s t h e c o o k i n g t i m e i s 188 p r o l o n g e d . T h e s e r e s u l t s i n d i c a t e a v i r t u a l a b s e n c e o f any l i g n i n r e c o n d e n s a t i o n r e a c t i o n s d u r i n g o r g a n o s o l v p u l p i n g . 26. S o l u b l e l i g n i n s do n o t s u f f e r r e c o n d e n s a t i o n a f t e r r e f l u x i n g t h e m f o r 54 h i n m e t h a n o l . 27. P r e c i p i t a t i o n o f t h e s o l u b l e l i g n i n f r o m t h e b l a c k l i q u o r b y d i l u t i o n a p p a r e n t l y c a n n o t remove a l l t h e t o x i c wood e x t r a c t i v e s f r o m a q u e o u s s o l u t i o n . 189 7. BIBLIOGRAPHY Abe, I . a n d K. Ono. 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M a s s s p e c t r u m o f 8 ( 1 4 ) , 1 5 - i s o p i m a r a d i e n - 1 8 - o a t e ( m e t h y l s a n d a r a c o p i m a r a t e ) F i g u r e A 3 . M a s s s p e c t r u m o f 7 , 1 5 - i s o p i m a r a d i e n - 1 8 - o a t e ( m e t h y l i s o p i m a r a t e ) F i g u r e A5. Mass s p e c t r u m o f 8 ( 1 4 ) , 1 2 - a b i e t a d i e n - 1 8 - o a t e ( m e t h y l l e v o p i m a r a t e ) F i g u r e A6 . M a s s s p e c t r u m o f 8 , 1 1 , 1 3 , - a b i e t a t r i e n - 1 8 - o a t e ( m e t h y l d e h y d r o a b i e t a t e ) F i g u r e A8. M a s s s p e c t r u m o f 8 ( 1 4 ) , 1 3 ( 1 5 ) - a b i e t a d i e n - 1 8 - o a t e ( m e t h y l n e o a b i e t a t e ) 212 APPENDIX B Mass s p e c t r a o f t h e most common f a t t y a c i d s p r e s e n t i n p i n e s p e c i e s F i g u r e B l . Mass s p e c t r u m o f h e x a d e c a n o a t e ( m e t h y l p a l m i t a t e ) nil ll. Ljjjdi 1 ill 1)1. i n ll* J^ W 1 1 1 - 1 \l- J L L.Jt.i,L, ...-Jut," L F i g u r e B2. Mass s p e c t r u m o f o c t a d e c a n o a t e ( m e t h y l s t e a r a t e ) F i g u r e B3. Mass s p e c t r u m o f 9 - o c t a d e c e n o a t e ( m e t h y l o l e a t e ) F i g u r e B4. Mass s p e c t r u m o f 9 , 1 2 - o c t a d e c a d i e n o a t e ( m e t h y l l i n o l e a t e ) F i g u r e B5. Mass s p e c t r u m o f 9 , 1 2 , 1 5 - o c t a d e c a t r i e n o a t e ( m e t h y l l i n o l e n a t e ) 

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