Open Collections

UBC Theses and Dissertations

UBC Theses Logo

UBC Theses and Dissertations

Black liquor extraction of lodgepole pine (Pinus Contorta var. Latifolia Engelm.) tree residues Wang, I-Chen 1980

Your browser doesn't seem to have a PDF viewer, please download the PDF to view this item.

Item Metadata

Download

Media
831-UBC_1981_A1 W36.pdf [ 8.46MB ]
Metadata
JSON: 831-1.0095167.json
JSON-LD: 831-1.0095167-ld.json
RDF/XML (Pretty): 831-1.0095167-rdf.xml
RDF/JSON: 831-1.0095167-rdf.json
Turtle: 831-1.0095167-turtle.txt
N-Triples: 831-1.0095167-rdf-ntriples.txt
Original Record: 831-1.0095167-source.json
Full Text
831-1.0095167-fulltext.txt
Citation
831-1.0095167.ris

Full Text

BLACK LIQUOR EXTRACTION OF LODGEPOLE PINE (£.11 US CONTORTA VAR. LATIFOLIA ENGELM.) TREE RESIDUES by I-CHEN [WANG M.Sc. U n i v e r s i t y Of B r i t i s h Columbia, 1975 A THESIS SUBMITTED IN THE REQUIREMENTS DOCTOR OF PARTIAL FULFILLMENT OF FOR THE DEGREE OF PHILOSOPHY i n the Department of F o r e s t r y accept t h i s t h e s i s as conforming to the r e q u i r e d standa THE UNIVERSITY OF BRITISH COLUMBIA (c) September, 1980 In presenting this thesis in p a r t i a l fulfilment of the requirements for an advanced degree at the University of B r i t i s h Columbia, I agree that the Library shall make it f r e e l y 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 representatives. It is understood that copying or publication of this thesis for f i n a n c i a l gain shall not be allowed without my written permission. Department The University of B r i t i s h Columbia 2075 Wesbrook Place Vancouver, Canada V6T 1WS Date i i ABSTRACT As a new f e a t u r e of complete t r e e u t i l i z a t i o n , lodgepole pine (Pinus c o n t o r t a var; l a t i f o l i a Engelnu) bark and t e c h n i c a l f o l i a g e ( f o l i a g e with twigs 6 mm or l e s s i n diameter) m i l l e d m a t e r i a l s were e x t r a c t e d with commercial k r a f t b l a c k l i q u o r s . Thereby, r e s i d u a l l i q u o r a l k a l i was used to s a p o n i f y l i p i d s and d i s s o l v e o r g a n i c components i n the m a t e r i a l s ; The o r i g i n a l l i q u o r s are r e i n f o r c e d by adding crude t a l l o i l , p h e n o l i c substances and s o l i d r e s i d u e from the bark and f o l i a g e . Crude t a l l o i l r e f e r s t o the a n a l y t i c a l recovery of l i p i d s a c c o r d i n g to the Saltsman and Kuiken method. P o t e n t i a l l i p i d y i e l d s of these t r e e r e s i d u e s and the e f f e c t s of v a r i o u s d r y i n g treatments were assessed as petroleum ether e x t r a c t s . Lodgepole pine bark and t e c h n i c a l f o l i a g e c o n t a i n e d 9.3 and 7.5% petroleum e t h e r s o l u b l e f r a c t i o n s , r e s p e c t i v e l y ; S i m i l a r amounts of crude t a l l o i l s were recovered i n the main study. S p e c i a l f r e e z e - d r y i n g and short p e r i o d a i r - d r y i n g preserved the l i p i d content, while oven-drying at 70 and 100°C s u b s t a n t i a l l y decreased e x t r a c t i v e recovery* Subsequently, bulk m a t e r i a l s f o r the main study were a i r - d r i e d f o r 4 to 6-days before m i l l i n g and t h e r e a f t e r meals were s t o r e d i n the c o l d (ca. 2<>C) under n i t r o g e n . Black l i q u o r e x t r a c t i o n s of the sample m a t e r i a l s were c a r r i e d out i n bomb cooks i n c l u d i n g two l i q u o r s t r e n g t h s ( o r i g i n a l and o r i g i n a l plus 5 g/1 sodium h y d r o x i d e ) , three i i i p a r t i c l e s i z e s (coarse, medium and f i n e f r a c t i o n s ) and 1:7 l i q u o r t o m a t e r i a l r a t i o . Maximum cooking temperatures of 80°, 100o f 1200, 145° and 170<>c were examined i n combination with v a r i o u s times at maximum temperature; Approximately one^-third of the s o l i d m a t e r i a l s were d i s s o l v e d f o l l o w i n g mixing and s t a n d i n g o v e r n i g h t at room temperature. These p o r t i o n s were not r e l e v a n t to the cooking process and based on t h i s c o r r e c t i o n the s o l i d r e s i d u e y i e l d s were found to e x h i b i t k i n e t i c s c l o s e to a second order r e a c t i o n . E m p i r i c a l expressions r e l a t i n g time-temperature cooking c o n d i t i o n s t o s o l i d r e s i d u e y i e l d s were developed from the Arrhenius equation. These contained e x p o n e n t i a l l y a d j u s t e d time terms, i ; e . , 0.45 f o r bark and 0.333 f o r t e c h n i c a l f o l i a g e . C o r r e l a t i o n s were e s t a b l i s h e d between crude t a l l o i l and s o l i d r e s i d u e y i e l d s ; Black l i q u o r e x t r a c t i o n provided an e f f i c i e n t means of r e c o v e r i n g bark and f o l i a g e l i p i d s . Even with the milder c o n d i t i o n s s t u d i e d (1.5-hr at 80°C) b e t t e r 1 t h a n 60% l i p i d r ecovery was achieved; S a p o n i f i c a t i o n seemed to be l e s s important i n c o n t r o l l i n g the crude t a l l o i l y i e l d than p h y s i c a l entrainment of t a l l o i l soaps i n the s o l i d r e s i d u e . Thus, hig h e r temperature and longer cooking time tended to d i s s o l v e more s o l i d m a t e r i a l and l i b e r a t e more crude t a l l o i l soap. In order t o gain i n f o r m a t i o n on progress of r e a c t i o n between black l i q u o r components and sample m a t e r i a l s , d i r e c t p o t e n t i o m e t r i c measurements were made during course of the r e a c t i o n a t 70°c with pH and sodium ion s e l e c t i v e e l e c t r o d e s ; Measurements i n d i c a t e d t h a t when samples were added to the l i q u o r , there was an immediate three orders decrease i n i v hydroxide i o n a c t i v i t y . Subsequent bulk l i q u o r a l k a l i consumption showed a slow and l i n e a r decrease i n hydroxide a c t i v i t y . T h i s i m p l i e s that a l k a l i consumption was c l o s e to a f i r s t order r e a c t i o n . Black l i q u o r e x t r a c t i o n i s advanced as a means f o r r e c o v e r i n g v a l u a b l e chemical components from abundant and underused c o n i f e r o u s f o r e s t r e s i d u e s . C o n s t r a i n t s on implementing the process are d i s c u s s e d * V TABLE OF CONTENTS Pages TITLE PAGE . i ABSTRACT i i TABLE OF CONTENTS v LIST OF TABLES v i i LIST OF FIGURES . . v i i i LIST OF APPENDICES .. X ACKNOWLEDGEMENTS x i I INTRODUCTION .... 1 I I LITERATURE REVIEW 6 1 Lodgepole Pine 6 1.1 Lodgepole Pine Subspecies ......................... 6 1.2 Morphology of Lodgepole Pine Bark and F o l i a g e ..... 7 1.2.1 Lodgepole Pine Bark 7 1.2.2 Lodgepole Pine F o l i a g e ........................ 8 1.3 Chemical Composition of Lodgepole Pine Bark and F o l i a g e . 9 1.3.1 Bark l i p i d s ... 9 1.3.2 Bark P h e n o l i c s 10 1.3.3 Bark Carbohydrates .... 11 1.3.4 F o l i a g e L i p i d s 12 2 S a p o n i f i c a t i o n 13 2.1 D e f i n i t i o n and Relevance to T h i s Study 13 2.2 Raction Mechanism and K i n e t i c s 14 2.3 H y d r o l y s i s Reaction 17 2.4 Some P r o p e r t i e s of Soaps 21 3 K r a f t P u l p i n g Process 25 3.1 K r a f t Pulping Process and Black L i q u o r E x t r a c t i o n 25 3.1.1 Cooking Liguor and Chemical Balances 25 3.2 K i n e t i c s and Cooking V a r i a b l e s 28 3.2.1 Time and Temperature E f f e c t s 29 3.2.2 L i g u o r C o n c e n t r a t i o n and Composition .......... 31 3.2.3 Other Cooking V a r i a b l e s 33 3.3 K r a f t Recovery Systems 34 3.3.1 Sodium C y c l e and Options ...................... 35 3.3.2 S u l f u r C y c l e and Options 37 3.3.3 Developments i n A l t e r n a t i v e K r a f t Recovery System 38 3.4 By-products of K r a f t Process 40 3. 4. 1 T a l l O i l 40 3.4.2 K r a f t L i g n i n ................................... 42 I I I MATERIALS AND METHODS 47 1 Petroleum Ether E x t r a c t i o n of Lodgepole Pine Samples .. 47 2 Black L i q u o r E x t r a c t i o n 49 3 E l e c t r o c h e m i c a l Techniques and Black Liquor E x t r a c -t i o n 52 v i Pages IV RESULTS AND DISCUSSION 56 1 Petroleum Ether E x t r a c t i o n of Lodgepole Pine Tree P a r t s 56 1.1 Choice of Solvent 56 1.2 General D i s c u s s i o n on the Drying E f f e c t 57 1.3 A n a l y s i s of Variances f o r Lodgepole Pine Tree P a r t s Petroleum Ether E x t r a c t s 59 1. 3. 1 Bark 60 1.3.2 T e c h n i c a l F o l i a g e ............................. 60 1.3.3 Sapwood 61 1. 3. 4 Heartwood 61 1.3.5 Pine Cones 62 2 Black L i q u o r E x t r a c t i o n 63 2.1 C h a r a c t e r i z a t i o n of BLE Procedures and R e s u l t s .... 63 2.2 Development of E m p i r i c a l E x p r e s s i o n s f o r BLE R e s u l t s 65 2.2.1 K i n e t i c Approaches to the BLE Problem 65 2.2.2 E m p i r i c a l Expressions f o r BLE R e s u l t s ......... 70 2.2.3 K i n e t i c s with Mass T r a n s f e r Approach to the BLE R e s u l t s 76 2.3 C o r r e l a t i o n s between Crude T a l l O i l Y i e l d s and S o l i d Residue 78 2.3.1 E f f e c t of P a r t i c l e S i z e 80 2.3.2 Cooking Temperature and Storage E f f e c t s 81 2.3.3 E f f e c t of Liquor Strength 81 2.3.4 S a p o n i f i c a t i o n and the BLE R e s u l t s 83 2.4 E l e c t r o c h e m i c a l M o n i t o r i n g of BLE 86 2.4.1 Background 87 2.4.2 C h a r a c t e r i z i n g Black L i q u o r by E l e c t r o c h e m i c a l Means 88 2.4.2.1 A c t i v e A l k a l i Determination 89 2.4.2.2 Sodium S u l f i d e Determination ... 89 2.4.3 D i r e c t Potentiometry .......................... 90 2.4.3.1 C a l i b r a t i o n L i n e s f o r D i r e c t Potentiomery . 92 A. Temperature C o r r e c t i o n 92 B. C o r r e c t i o n f o r L i q u i d - J u n c t i o n P o t e n t i a l . 92 C. C o r r e c t i o n f o r Sodium E r r o r 94 2.4.3.2 D i r e c t Potentiometry of the Black L i q u o r and the BLE * 95 A. The Black Liquor 95 B. The BLE . . . 95 2.5 P o t e n t i a l s and C o n s t r a i n t s of BLE . .; 98 2.5.1 Complete Tree U t i l i z a t i o n and BLE I 99 2.5.2 Some C o n s t r a i n t s on BLE 101 3 Recommendations ..; 102 V CONCLUSION 1 04 VI LITERATURE CITED .......... . .................... 105 v i i LIST OF TABLES pages Table 1. Petroleum ether e x t r a c t i o n of lodgepole pine t r e e p a r t s expressed as percentages of 0-D m a t e r i a l s (n = 3) 117 Table 2. A n a l y s i s of v a r i a n c e f o r petroleum e t h e r e x t r a c t i o n of lodgepole pine bark. 118 Table 3. A n a l y s i s of v a r i a n c e f o r petroleum ether e x t r a c t i o n of lodgepole pine t e c h n i c a l f o l i a g e . 119 Table 4. A n a l y s i s of v a r i a n c e f o r petroleum ether e x t r a c t i o n of lodgepole pine sapwood. 120 Table 5. A n a l y s i s of v a r i a n c e f o r petroleum e t h e r e x t r a c t i o n of lodgepole pine heartwood 121 Table 6. A n a l y s i s of v a r i a n c e f o r petroleum e t h e r e x t r a c t i o n of lodgepole pine cones 122 Table 7. Sieve analyses of BLE lodgepole pine m a t e r i a l s as percentage of sample r e t a i n e d on screen. 123 Table 8. BLE cooking schemes 124 Table 9. M o d i f i e d H-factor c a l c u l a t e d from the Arrhenius equation f o r BLE lodgepole pine bark and t e c h n i c a l f o l i a g e . 125 Table 10. C a l i b r a t i o n of pH and sodium i o n s e l e c t i v e e l e c t r o d e p o t e n t i a l s i n standard sodium hydroxide s o l u t i o n s at 2S°C. 126 v i i i LIST OF FIGURES pages F i g 1. BLE cooking schemes as time-temperature p r o f i l e s . T r a n s c r i b e d from the F o r i n t e k automatic temperature r e g i s t e r c h a r t s . Arrows i n d i c a t e t e r m i n a t i o n p o i n t s of the time s e r i e s cooks 127 F i g 2. Diagram of the manual press f i l t e r used i n s e p a r a t i n g black l i q u o r s from s o l i d r e s i d u e s * 128 F i g 3. Schematic diagram of the BLE d i r e c t p o t e n t i o -metric monitoring* * 129 F i g 4. S o l i d r e s i d u e (SR) y i e l d s vs. cooking times f o l l o w i n g black l i q u o r e x t r a c t i o n of lodgepole pine pine bark and t e c h n i c a l f o l i a g e * Time s c a l e i s the r e l a t i v e l e n g t h of cooking p e r i o d f o r a p a r t i c u l a r temperature-time s e r i e s 130 F i g 5. S o l i d r e s i d u e (SR) y i e l d s as f i r s t o rder p l o t s with r e s p e c t to cooking times f o l l o w i n g black l i q u o r e x t r a c t i o n of lodgepole pine bark and t e c h n i c a l f o l i a g e * A 20-g b a s i s per sample i s assumed f o r the i n i t i a l SR. Regression l i n e s are extended to b e t t e r show the s l o p e s and are not intended as e x t r a p o l a t i o n s 131 F i g 6. S o l i d r e s i d u e (SR) y i e l d s as second order p l o t s with r e s p e c t to cooking times f o l l o w i n g black l i q u o r e x t r a c t i o n of lodgepole p i n e bark and t e c h n i c a l f o l i a g e * A 20-g b a s i s per sample i s assumed f o r the i n i t i a l SR. Regression l i n e s are extended to b e t t e r show the s l o p e s and are not intended as e x t r a p o l a t i o n s 132 F i g 7. Arrhenius p l o t f o r determining lodgepole pine bark (Yb) and t e c h n i c a l f o l i a g e (Yf) BLE apparent e n e r g i e s of a c t i v a t i o n . S u b s c r i p t numbers are r e a c t i o n orders 133 F i g 8. BLE e m p i r i c a l f u n c t i o n s i n r e l a t i o n to lodgepole pine bark (Yb) and t e c h n i c a l f o l i a g e (Yf) s o l i d r e s i d u e (SR) data. A 20-g weight b a s i s per sample f o r SR i s assumed* .... 134 i x Pages F i g 9. BLE e m p i r i c a l f u n c t i o n s i n r e l a t i o n to lodgepole pine bark (Yb) and t e c h n i c a l f o l i a g e (Yf) r e c i p r o c a l s o l i d r e s i d u e (SR) data. A 20-g weight b a s i s per sample f o r SR i s assumed. 135 Fi g 10. C o r r e l a t i o n between lodgepole pine bark BLE t o t a l crude t a l l o i l (TTO) and s o l i d r e s i d u e (SR). Both v a r i a b l e s are expressed as percentages of o r i g i n a l sample O-D weights; TTO data are c o r r e c t e d f o r i n i t i a l t a l l o i l content of black l i q u o r s (N i s the o r i g i n a l l i q u o r ; and R i s the o r i g i n a l r e i n f o r c e d with 5 g/1 sodium hydroxide) 136-F i g 11. C o r r e l a t i o n between lodgepole pine t e c h n i -c a l f o l i a g e BLE t o t a l crude t a l l o i l (TTO) and s o l i d r e s i d u e (SR). Both v a r i a b l e s are expressed as percentages of o r i g i n a l sample 0-D weights. TTO data are c o r r e c t e d f o r i n i t i a l t a l l o i l contents of black l i q u o r s (N i s the o r i g i n a l l i g u o r ; and R i s the o r i g i n a l r e i n f o r c e d with 5 g/1 sodium hydroxide) 137 F i g 12. P o t e n t i o m e t r i c t i t r a t i o n of the b l a c k l i g u o r a c t i v e a l k a l i . 138 F i g 13. A r g e n t i m e t r i c t i t r a t i o n f o r black l i q u o r sodium s u l f i d e d e terminations (A i s unoxidized black l i q u o r with b u f f e r ; B i s o x i d i z e d black l i q u o r without b u f f e r ; and C i s o x i d i z e d black with buffer) 139 F i g 14. C a l i b r a t i o n curve f o r d i r e c t potentiometry of sodium i o n s e l e c t i v e e l e c t r o d e . C i r c l e s denote the observed p o t e n t i a l s and dots are the c o r r e c t e d p o t e n t i a l s (adjusted f o r l i q u i d - j u n c t i o n p o t e n t i a l s ) 140 Fi g 15. C a l i b r a t i o n curve f o r d i r e c t potentiometry of hydroxide i o n . C i r c l e s denote the observed p o t e n t i a l s and dots are the c o r r e c t e d p o t e n t i a l s (adjusted f o r sodium e r r o r and l i q u i d - j u n c t i o n p o t e n t i a l s ) 141 F i g 16. D i r e c t p o t e n t i o m e t r i c monitoring of BLE of l odgepole pine bark* t e c h n i c a l f o l i a g e and sapwood samples at 70°C. 142 X LIST OF APPENDICES pages Appendix 1. Scanning electronraicrographs of lodgepole pine bark samples 143 Appendix 2. Petroleum ether e x t r a c t i o n of lodgepole pine t r e e p a r t s (data from f l a s k weight gain expressed as percent 0-D m a t e r i a l weight, n = 3) 144 Appendix 3. Black l i q u o r e x t r a c t i o n r e s u l t s of lodgepole pine t r e e p a r t s (30-g 0-D m a t e r i a l ; 200-ml l i q u o r ) 147 Appendix 4. Data and equations f o r BLE c a l c u l a t i o n s * 151 x i ACKNOWLEDGEMENTS The author wishes to express s i n c e r e g r a t i t u d e t o Dr. J . W. Wilson, P r o f e s s o r , F a c u l t y of F o r e s t r y , U n i v e r s i t y of B r i t i s h Columbia, f o r h i s guidance and s u p e r v i s i o n of the t h e s i s . Thanks are due a l s o to Weyerhaeuser Canada L t d . (Kamloops), f o r h e l p i n g to secure the black l i g u o r and experimental m a t e r i a l s ; and to F o r i n t e k Canada Corp. f o r use of d i g e s t e r f a c i l i t i e s . Mr. W. Y. Gee k i n d l y c a r r i e d out the cooks; The author wishes to express g r a t i t u d e e s p e c i a l l y to Ms. G. C a s s a r - T o r r e g g i a n i f o r helpin g i n t a l l o i l a n a l y s e s , and Mrs. C-I. Wu at Simon F r a s e r U n i v e r s i t y f o r doing scanning e l e c t r o n micrographs of bark samples. Messrs. G. Bonhenkamp and E. Burke were h e l p f u l i n a c q u i r i n g equipment and chemicals. F i n a n c i a l a s s i s t a n c e from Weyerhaeuser Co. and the U n i v e r s i t y of B r i t i s h Columbia i s g r a t e f u l l y acknowledged, as i s the continued a c t i v e i n t e r e s t of Dr. R. E. K r e i b i c k , Manager, Chemistry Department, Weyerhaeuser Co;, Tacoma; Dr: S. Chow, Manager, Research and Ap p l i e d S c i e n c e , Canadian Fore s t Products L t d ; , k i n d l y served as l i a i s o n o f f i c e r with the Weyerhaeuser Company. 1 I INTRODUCTION The age of cheap and p l e n t i f u l petroleum products has ended* The d o u b t f u l f u t u r e of the remaining resource has prompted s e a r c h f o r a l t e r n a t i v e energy and chemical raw m a t e r i a l sources. I n c r e a s i n g a t t e n t i o n i s now d i r e c t e d toward s o - c a l l e d "renewable r e s o u r c e s " f o r the s o l u t i o n . Biomass as source of chemicals and energy has been e x t e n s i v e l y s t u d i e d , e s p e c i a l l y i n response to changes i n petroleum s u p p l i e s . There are s e v e r a l o p t i o n s p o s s i b l e . G o l d s t e i n (48,49) i s among the most ardent advocates f o r use of biomass as a chemical raw m a t e r i a l source. He sees renewable f o r e s t r e s o u r c e s v i r t u a l l y r e p l a c i n g petroleum as raw m a t e r i a l s f o r some b a s i c chemicals, such as ethanol* butadiene, a c e t i c a c i d and e t h y l e n e , which are the corner stones of modern s y n t h e t i c chemistry. Polymers and p l a s t i c s can a l s o be produced from t r e a t i n g and r e p o l y m e r i z i n g c e l l u l o s e and l i g n i n . Other r e s e a r c h e r s (80,102) s t i l l see petroleum and c o a l as the main m a t e r i a l sources f o r the chemical i n d u s t r i e s * Biomass resources are considered to be non-competitive with these t r a d i t i o n a l sources f o r b a s i c chemical products. S t i l l , p o t e n t i a l of the biomass resources i s recognized as a route to gen e r a t i n g s p e c i a l i z e d chemical products t h a t take advantage of unique, n a t u r a l molecular s t r u c t u r e s . In t h i s , more i n t e n s i v e u t i l i z a t i o n of the f o r e s t resource i s a c e r t a i n t y i n the f u t u r e * Wastefulness i s p r e v a l e n t i n c o n v e n t i o n a l u t i l i z a t i o n of the f o r e s t r e s o u r c e . Only the prime p o r t i o n s of t r e e boles are s e l e c t e d , while more than h a l f the f o r e s t biomass i s l e f t at 2 l o g g i n g s i t e s , or p i l e d at m i l l s as waste m a t e r i a l s or " r e s i d u e s " . T h i s not only c r e a t e s environmental problems but c o n t r a d i c t s p r i n c i p l e s of conserving n a t u r a l r e s o u r c e s . The complete t r e e u t i l i z a t i o n (CTU) concept has been around f o r some time to counter t h i s wastefulness; I t has been put to some l i m i t e d p r a c t i c e i n the f o r e s t products i n d u s t r i e s . As e x e m p l i f i e d i n the pulp m i l l o p e r a t i o n , however, a d d i t i o n of chipped whole t r e e p a r t s t o the process before d i g e s t i o n e i t h e r lowers pulp q u a l i t y or r e q u i r e s continuous monitoring to minimize d e t r i m e n t a l e f f e c t s from adding l e s s d e s i r a b l e t r e e s p e c i e s , s i z e s or p a r t s . P r e s e n t l y , CTU serves mostly to f u r n i s h a d d i t i o n a l f u e l v a l u e s, s i n c e other proposals have been mostly economically u n a t t r a c t i v e ; In t h i s t h e s i s an a l t e r n a t i v e s o l u t i o n to problems f a c i n g CTU p r a c t i c e i s explored; Instead of p u t t i n g t r e e r e s i d u e s d i r e c t l y t o the d i g e s t e r , s u i t a b l y d i v i d e d t r e e r e s i d u e s are e x t r a c t e d with k r a f t black l i g u o r a f t e r the p u l p i n g d i g e s t i o n , e i t h e r i n or o f f stream, but before the recovery f u r n a c e . T h i s process i s named Black Liquor E x t r a c t i o n (BLE). T h i s novel approach should circumvent many CTU problems and may o f f e r a v i a b l e means of u t i l i z i n g biomass r e s o u r c e s . BLE of t r e e r e s i d u e s can r e s u l t i n f o u r products, as: Crude s u l f a t e t u r p e n t i n e ; Crude t a l l o i l ; L i g n i n and p h e n o l i c substances; and S o l i d r e s i d u e s . Under e l e v a t e d cooking temperature, v o l a t i l e components, mostly mono- and sesquiterpenes become vaporized and are r e c o v e r a b l e from the r e l i e f gas by condensation. BLE could enhance the crude t u r p e n t i n e y i e l d from pulping wood alone; I t 3 s h o u l d be n o t e d , however, t h a t due t o t h e t y p e o f d i g e s t e r bomb used i n t h e p r e s e n t s t u d y , no r e l i e f gas r e c o v e r y was p o s s i b l e . T h u s , t h e s e f r a c t i o n s were n o t r e c o v e r e d . O l e o r e s i n components from t r e e r e s i d u e s c o n s i s t m o s t l y o f r e s i n a c i d s , f a t t y a c i d s and f a t t y a c i d t r i g l y c e r i d e s ( f a t s ) . These s h o u l d be s a p o n i f i e d and c o n v e r t e d i n t o s o l u b l e sodium s a l t s ( soaps) e v e n by t h e u s e d a l k a l i n e p u l p i n g medium. By c o n -c e n t r a t i n g , c o o l i n g , a e r a t i n g and s t a n d i n g o f t h e b l a c k l i q u o r , s uch s o a p s a r e known t o s e p a r a t e and t h e y c a n be skimmed o f f * A c i d i f i c a t i o n o f t h e s oaps t h e r e a f t e r y i e l d s c r u d e t a l l o i l . T a l l o i l p r i c e s have gone up s u b s t a n t i a l l y o v e r t h e p a s t few y e a r s , r e n d e r i n g r e c o v e r y d e s i r a b l e and even n e c e s s a r y t o good k r a f t p u l p i n g e c o n o m i c s . M e a n w h i l e , due t o i n c r e a s i n g p r o p o r t i o n s o f immature p i n e t r e e s i n pulpwood f u r n i s h e s , which c o n t a i n r e l a t i v e low o l e o r e s i n amounts, t a l l o i l y i e l d s have p r o b l e m s i n k e e p i n g up w i t h demand ( 1 7 ) . The BLE p r o c e s s p r o v i d e s a v i a b l e means f o r i n c r e a s i n g t h e c r u d e t a l l o i l s u p p l y . The h i g h e r p r o p o r t i o n o f l o n g c h a i n f a t t y a c i d s i n bark a l s o c o u l d have t h e added b e n e f i t o f i m p r o v i n g t a l l o i l s o a p s e p a r a t i o n and f u r t h e r i n c r e a s i n g y i e l d . K r a f t l i g n i n s p r e s e n t l y have low u t i l i z a t i o n i n t e n s i t y b e s i d e s b e i n g b u r n e d i n r e c o v e r y f u r n a c e s t o g e n e r a t e h e a t . Wood p h e n o l i c components, s u c h as c a t e c h o l s and t a n n i n s r e p r e s e n t o n l y a v e r y s m a l l f r a c t i o n o f p r e s e n t b l a c k l i q u o r s o l i d s and a r e u n e c o n o m i c a l t o r e c o v e r . S o f t w o o d b a r k s , on t h e o t h e r hand, a r e w e l l known t o h a v e r i c h p h e n o l i c f r a c t i o n s (22 ,63 ) . These d i s s o l v e t o g r e a t e x t e n t i n s o d i um h y d r o x i d e s o l u t i o n . U n d o u b t e d l y b a r k BLE would e n r i c h p h e n o l i c v a l u e s i n l i q u o r s . 4 The remaining s o l i d r e s i d u e s a f t e r BLE of barks and f o l i a g e s have p o t e n t i a l uses as f u e l s * glue extenders, f i b e r sources and p o s s i b l y even animal feeds. To use the r e s i d u e s as f u e l s , they could be removed from the k r a f t l i g u o r stream and burned i n a c o n v e n t i o n a l power b o i l e r or a converted recovery furnace that can accept s o l i d f u e l m a t e r i a l s (72,153). In an a s s o c i a t e d small s c a l e experiment, p u l v e r i z e d r e s i d u e of l o d g e p o l e pine bark and f o l i a g e s o l i d s were s a t i s f a c t o r y glue extenders, comparable i n performance to some commercial products (127). From other work ( 7 ) the t o t a l d i g e s t a b l e n u t r i e n t s of lodgepole pine f o l i a g e used f o r animal feed were found to compare f a v o r a b l y with grass hay, i . e . , greater than 53%. BLE of the f o l i a g e , e s p e c i a l l y a t lower temperature, should remove a c i d i c and p h e n o l i c f r a c t i o n s while adding l i t t l e s u l f u r contaminant to the f o l i a g e , thereby r e n d e r i n g e x t r a c t e d f o l i a g e more s u i t a b l e as feed stock. P o t e n t i a l use of softwood needles as f i b e r source has been explored r e c e n t l y (91), although product p r o p e r t i e s leave much t o be d e s i r e d , the study d i d show that such usage i s to some extent g u i t e p o s s i b l e . BLE i s foreseen as having advantages i n t h a t : 1. B e n e f i t s a t t r i b u t e d to CTU are a l s o a p p l i c a b l e t o the BLE process; 2. Tree r e s i d u e values i n the f o r e s t s and at m i l l s i t e s are upgraded; 3. There i s no i l l e f f e c t on the main p r o d u c t — k r a f t pulp, u n l e s s t r e e r e s i d u e s are mixed with wood c h i p s p r o p o s e f u l l y ; 4. Otherwise marginal recovery of by-products from the t r a d i -t i o n a l sources i s r e i n f o r c e d ; 5 5. Black l i q u o r s o l i d s i n c r e a s e with d i s s o l u t i o n of r e s i d u e components, t h e r e f o r e reducing the r e l a t i v e amount of water to be evaporated; 6. The process operates independently of the petroleum i n d u s t r y , e i t h e r as a raw m a t e r i a l source f o r chemicals or as an energy source; and 7. F l e x i b i l i t y of the process allows a d a p t a t i o n to market needs. C e r t a i n disadvantages a l s o need to be co n s i d e r e d , such as: 1. Higher ash content i n barks and f o l i a g e s , and i n c r e a s e d p o s s i b i l i t y of c a r r y i n g d i r t from l o g g i n g and storage s i t e s ; 2. I n t r o d u c i n g f o r e i g n m a t e r i a l s i n t o the black l i q u o r recovery system, which may pose o p e r a t i n g problems; and 3. Recovery of p h e n o l i c and l i g n e o u s substances from the l i q u o r streams c o u l d r e q u i r e changes i n pH from a l k a l i n e to a c i d i c c o n d i t i o n s . O b j e c t i v e s o f the work d e s c r i b e d i n t h i s t h e s i s are to t e s t some of these new idea s by: 1. Examining f e a s i b i l i t y of BLE which i s novel t o t h i s t h e s i s ; 2. Determining p o t e n t i a l crude t a l l o i l amounts i n lodgepole pine t r e e p a r t s , i . e ; , through d i r e c t petroleum ether e x t r a c t i o n ; 3. E s t a b l i s h i n g an e m p i r i c a l e x p r e s s i o n f o r r e l a t i n g BLE r e s u l t s with lodgepole pine bark and f o l i a g e t o cooking c o n d i t i o n s ; and 4. Experimenting with e l e c t r o c h e m i c a l means f o r studying the BLE process. 6 I I LITERATURE REVIEW 1 Lodgepole Pine T h i s study concerns the u t i l i z a t i o n of lodgepole pine (PiQ-MS c g n t o r t a Dougl;) r e s i d u a l t r e e p a r t s , e s p e c i a l l y bark and f o l i a g e . A review of l i t e r a t u r e on v a r i o u s aspects of these r e s i d u a l t r e e components i s i n c l u d e d to e s t a b l i s h p o t e n t i a l s and c o n s t r a i n t s on u t i l i z a t i o n . Because of the t r a d i t i o n a l low i n t e r e s t l e v e l i n bark and f o l i a g e u t i l i z a t i o n , there i s l i t t l e i n f o r m a t i o n i n t h i s regard. The term lodgepole pine r e f e r s to both the s p e c i e s (E- contorta) i n g e n e r a l and the subspecies P. c o n t o r t a var. l a t i f o l i a i n p a r t i c u l a r which the sample m a t e r i a l s r e p r e s e n t . 1.1 Lodgepole Pine Subspecies Lodgepole pine (Pinus c o n t o r t a Dougl.) i s a c o n i f e r o u s t r e e of western North America. S e v e r a l h i g h l y d i f f e r e n t i a t e d forms of the s p e c i e s are noted. The most common d i s t i n c t i o n s , e s p e c i a l l y i n B r i t i s h Columbia, are the c o a s t a l form, P. c o n t o r t a var. c o n t o r t a (Dougl.) and the i n t e r i o r or Rocky Mountain form, P. c o n t o r t a v a r . l a t i f o l i a (Engelm.). The former , sometimes c a l l e d shore pine, i s t h i c k barked, r e l a t i v e l y s h o r t l i v e d , branchy and with s h o r t and narrow l e a v e s . I t i s mostly c o n f i n e d to marginal s i t e s i n c o a s t a l lowlands. The l a t t e r , which i n c l u d e s most commerical stands of l o d g e p o l e pine, i s u s u a l l y t h i n barked, t a l l with small diameter and with l o n g , moderately wide l e a v e s . 7 C r i t c h f i e l d (29) proposed a more d e t a i l e d s u b d i v i s i o n f o r lodgepole pine i n t o f o u r subspecies. In a d d i t i o n to the c o a s t a l race and Rocky Mountain-Intermountain races as above, he adds a Sierra-Cascade race (ssp. murrayana) and a Mendocino White P l a i n race (ssp. bolanderi) . Lodgepole pine i s one of the most wide-spread American p i n e s , r a n g i n g from the Yukon t o Baja C a l i f o r n i a , spanning 33 degrees of l a t i t u d e . I t i s found from the Northwest P a c i f i c coast to the South Dakota Black H i l l s * I t s e l e v a t i o n a l d i s t r i -b u tion from sea l e v e l to t i m b e r l i n e b r a c k e t s the e n t i r e t r e e growing zone. Throughout much of the i n t e r i o r west, i t i s a major t r e e s p e c i e s , c o v e r i n g n e a r l y 260 m i l l i o n ha* of f o r e s t l a n d . T h i s hardy s p e c i e s has been i n t r o d u c e d f o r commercial f o r e s t s i n many European c o u n t r i e s . 1.2 Morphology of Lodgepole Pine Bark and F o l i a g e 1.2.1 Lodgepole Pine Bark Chang (21) d e s c r i b e d North America pulpwood barks i n d e t a i l and remains the main source of i n f o r m a t i o n on the t o p i c * The gene r a l f e a t u r e s of lodgepole pine bark and some c h a r a c t e r i s t i c f e a t u r e s t h a t render the bark r i c h i n extraneous substances are reviewed* Mature lodgepole pine bark from the c o a s t a l v a r i e t y i s r a t h e r t h i c k , up to 2.5 cm at trunk base, reddish-brown i n c o l o r , rough, r i d g e d and furrowed with c l o s e l y appressed s c a l e s . The i n t e r i o r t r e e s have much t h i n n e r barks, about 0.6 cm i n t h i c k n e s s , which are l i g h t yellowish-brown i n c o l o r , u s u a l l y unridged and unfurrowed, as w e l l as with l o o s e l y appressed. 8 t h i n , s m a l l s c a l e s . G e n e r a l l y the outer bark shows narrow rhytidome l a y e r s with t h i n periderms. The i n n e r bark i s narrow but with f i n e r t e x t u r e and l i g h t e r c o l o r e d phloenu The Rocky Mountain lodgepole pine bark d i f f e r s from other pine barks i n having narrow secondary phloem i n both i n n e r bark and rhytidome, s p o r a d i c a l l y d i s t r i b u t e d phloem parenchyma, and by having numerous l a r g e r e s i n c a n a l s . H o r i z o n t a l r e s i n c a n a l s appear as p a r t s of f u s i f o r m rays with 3 to 4 l a y e r s of t h i n - w a l l e d e p i t h e l i a l c e l l s surrounding inner a p e r t u r e s . Resin c a n a l s sometimes enl a r g e up to a diameter of 1.5 t o 2 mm. The phelloderm c e l l s are parenchymatous and c o n t a i n some re s i n o u s substances and s m a l l c r y s t a l s (Appendix 1). 1.2.2 Lodgepole Pine F o l i a g e There are two kinds of mature l e a v e s on lodgepole pine. The f i r s t are s c a l e - l i k e , membraneous leaves i n the a x i l s of the spurs, f a i r l y s m a l l , about 0.3 to 0.6 cm i n l e n g t h . The second type are n e e d l e - l i k e leaves with the former type of leaves forming a sheath around t h e i r base. They are i n c l u s t e r s of two, and are 2.5 t o 8 cm i n l e n g t h , and 1 to 3 mm i n width. The needles are o f t e n s p i r a l l y t w i s t e d and densely envelope the branches* There are numerous w h i t i s h s t o m a t i c l i n e s on the s u r f a c e s . Leaves are s e m i - c i r c u l a r shaped i n c r o s s s e c t i o n . There are r e s i n c a n a l s embedded i n mesophyll near the hypodermis of each needle. In the center of each needle there i s an endodermis l a y e r surrounding a v a s c u l a r t i s s u e c o n s i s t i n g of xylem and phloem ( 4 ). 9 1.3 Chemical Composition of Lodgepole Pine Bark and F o l i a g e 1.3.1 Bark L i p i d s Systematic and comprehensive chemical analyses of lod g e p o l e pine barks seems to be wanting, and only scant i n f o r m a t i o n i s a v a i l a b l e . Chang and M i t c h e l l (22) s t u d i e d the chemical composition of 24 common North American pulpwood barks and found t h a t lodgepole pine bark from Rocky Mountain areas (Carson, Wash, sample no. u n s p e c i f i e d ) was unigue i n c o n t a i n i n g 28.7% benzene s o l u b l e e x t r a c t i v e s , while most of the c o n i f e r o u s barks contained only 2 to 5% benzene e x t r a c t i v e s ; T h e i r u n u s u a l l y high e x t r a c t i v e content has prompted some comment, s i n c e other i n v e s t i g a t i o n s of the same s u b j e c t have turned up y i e l d s of only 4% or so (128). Shrimpton (133) noted t h a t mountain pine b e e t l e s which mine the phloem r e g i o n of pine bark may i n t r o d u c e blue s t a i n f u n g i which i n t u r n cause the tre e to i n c r e a s e p r o d u c t i o n of v o l a t i l e o i l s and other e x t r a c t i v e s . Hunt and Kuechler (70) a l s o speculated that i n f e c t i o n by fungus, such as A t r o p e 1 l i s p i n i p h i l a , may induce excess e x t r a c t i v e s e c r e t i o n by pine t r e e s ; Rowe and Scroggins (129) f r a c t i o n a t e d the lodgepole pine bark (from Gor Pass, Colo, sample no. u n s p e c i f i e d ) benzene e x t r a c t and found i t contained 42.6% f r e e a c i d s , 9.4% combined a c i d s , 2% s t e a m - v o l a t i l e t e r p e n o i d s , 38% higher t e r p e n o i d s , 3% b e t a - s i t o s t e r o l , 1.8% wax a l c o h o l s and other minor components. They b e l i e v e d some of the dit e r p e n e a l c o h o l s , p a r t i c u l a r l y the predominant epimanool, could be p r e c u r s o r s of d i t e r p e n e r e s i n a c i d s . Lodgepole pine bark combined a c i d s were analyzed and 10 c o n t a i n e d 26.8% s a t u r a t e d a c i d s with behenic (C-22), a r a c h i d i c (C-20) , p a l m i t i c (C-16) and l i g n o c e r i c (C-24) predominant. The 71.6% unsaturated a c i d f r a c t i o n c o n t a i n e d l i n o l e i c , o l e i c , 5 , 9 , 1 2 - o c t a d e c a t r i e n o i c a c i d s and a f a i r l y l a r g e p r o p o r t i o n of complex unsaturated higher a c i d s . I t i s noteworthy t h a t two s e t s of a c i d s were present, the long c h a i n wax a c i d s , l i k e behenic and l i g n o c e r i c a c i d s , and the t y p i c a l f a t t y a c ids* Hartman and Weenink (59) found a completely d i f f e r e n t f a t t y a c i d p a t t e r n f o r lodgepole pine bark and wood t a l l o i l . They noted a high p r o p o r t i o n of s a t u r a t e d C-20 and C-24 ( a r a c h i d i c and l i g n o c e r i c ) a c i d s i n pine bark and only t r a c e s of these i n t a l l o i l . Shrimpton (133) analyzed v o l a t i l e o i l s from f i v e i n t e r i o r lodgepole pine bark samples and found t h a t the predominant monoterpene hydrocarbons were beta-phellandrene, alpha-pinene, beta-pinene, camphene, 3-carene and t e r p i n o l e n e * C e r t a i n oxygenated terpenes present were d e s c r i b e d as a l p h a - t e r p i n e o l , borneol, i s o b o r n e o l , e s t r a g o l e , b e t a - c a r y o p h y l l e n e , b o r n y l a c e t a t e and t e r p i n e n e - 4 - o l . However, the t o t a l v o l a t i l e o i l y i e l d s ranged from only 0.05 to 0.15% of the f r e s h bark weight. F o r r e s t (46) d i s c o v e r e d that monoterpenes from the c o r t i c a l r e s i n of lodgepole pine e x t r a c t e d from c u r r e n t year t e r m i n a l s i d e - s h o o t s a t l e a s t four years o l d gave c h a r a c t e r i s t i c i n f o r m a t i o n on region of t r e e o r i g i n . Large numbers of B r i t i s h and North American provenances have been tested* T h i s gives some i n d i c a t i o n as to the s p e c i e s v a r i a b i l i t y i n s i l v i - c h e m i s t r y . 1.3.2 Bark P h e n o l i c s Chang and M i t c h e l l (22) found t h a t 72.9% of lodgepole pine 11 bark m a t e r i a l was s o l u b l e i n 1% NaOH s o l u t i o n , the highest among the s p e c i e s s t u d i e d . Upon 1:10 a d d i t i o n of concentrated h y d r o c h l o r i c a c i d to the u n d i l u t e d a l k a l i e x t r a c t , 29.9% of the o r i g i n a l bark m a t e r i a l was p r e c i p i t a t e d . A d d i t i o n a l p h e n o l i c substances may be present which can condense with formaldehyde. The a l k a l i e x t r a c t e d bark was t r e a t e d with 72% s u l f u r i c a c i d to give 5.1% i n s o l u b l e l i g n e o u s substance. Since t h e r e i s evidence to i n d i c a t e that bark " l i g n i n " i s s u b s t a n t i a l l y d i f f e r e n t from wood l i g n i n (82), a d i s t i n c t i o n should be maintained. A l k a l i e x t r a c t i o n d i s s o l v e d a " l i g n i n " f r a c t i o n c o n t a i n i n g l e s s methoxyl than the a l k a l i - i n s o l u b l e f r a c t i o n . Lodgepole pine bark a l s o c o n t a i n e d p r o p o r t i o n a l l y l e s s methoxyl i n i t s bark " l i g n i n " than most other pulpwood s p e c i e s . Hergert (63) i n v e s t i g a t e d the f l a v o n o i d content of lodge-pole pine bark. The c o a s t a l v a r i e t y bark was found to c o n t a i n about 2.0% m y r i c e t i n , which accounted f o r 90% of the t o t a l f l a v o n o i d f r a c t i o n ; Small amounts of g u e r c e t i n , dihydroguoce-t i n , d i h y d r o m y r i c e t i n , aromadendrin and pinobanksin were a l s o present. Bark of i n t e r i o r v a r i e t y has much lower f l a v o n o i d content, with y i e l d at about 1%. In an e a r l i e r r e p o r t ( 3 ) t a n n i n from lodgepole pine bark was e x t r a c t e d and found s u i t a b l e f o r tanning l e a t h e r , but the y i e l d was too low to make e x t r a c t i o n commercially p r a c t i c a l . 1.3.3 Bark Carbohydrates Chang and M i t c h e l l (22) examined reducing sugar contents of v a r i o u s North American pulpwood barks. Lodgepole pine was found to c o n t a i n 38.3% reducing sugars by treatment with 72% s u l f u r i c 12 a c i d , which was i n t e r m e d i a t e among the s p e c i e s s t u d i e d . About h a l f of these carbohydrate f r a c t i o n s were d i s s o l v e d i n 1% NaOH s o l u t i o n . On an e x t r a c t i v e - f r e e b a s i s ( p r e - e x t r a c t e d with benzene), r e d u c i n g sugar y i e l d was 32.9%. Composition of lodgepole pine bark reducing sugars showed l e s s glucose than with most other barks s t u d i e d , with glucose comprising only 50% of a l l s u g a r s . There was 26% ara b i n o s e , the highest among a l l the barks. T i m e l l (149) a l s o s t u d i e d p o l y s a c c h a r i d e s from v a r i o u s c o n i f e r o u s barks. His r e s u l t s c o r r o b o r a t e d the o b s e r v a t i o n t h a t lodgepole pine i n n e r bark has an e x c e p t i o n a l l y high arabinose content, amounting to 10.6% of e x t r a c t i v e - f r e e ( e x t r a c t e d with b o i l i n g e thanol and then 1:2 ethanol:benzene) bark weight. In hot water e x t r a c t s of e x t r a c t i v e - f r e e bark, arabinose made up 44% of the t o t a l sugar r e s i d u e as compared with 28% f o r glucose. He noted a l s o t h a t the bark has fewer a c e t y l groups and higher uronic anhydride and g a l a c t o s e contents than the wood. 1.3.4 F o l i a g e L i p i d s Pauly and von R u d l o f f (118) s t u d i e d Rocky Mountain lodgepole pine l e a f o i l s i n l i g h t of chemosystematics; Gas chromatography showed beta-phellandrene and beta-pinene as the major components. Lesser amounts of alpha-pinene, myrcene, cis-ocimene, 3-carene, t e r p i n o l e n e , gamma-terpinene, a l p h a - t e r p i n e o l , t e r p i n e n - 4 - o l , e s t r a g o l e , b o r n y l a c e t a t e , l i n a l o o l and s e s q u i t e r p e n e s l i k e cadinene* c a d i n o l , n e r o l i d o l and muurolol isomers. The average l e a f o i l y i e l d by steam d i s t i l l a t i o n was 0.24% by weight. There were s i m i l a r trends i n 13 f o l i a g e o i l composition as with bark and wood o l e o r e s i n s . V a r i a t i o n i n the r e l a t i v e amounts of l e a f terpenes at v a r i o u s h e i g h t s on a s i n g l e t r e e was s m a l l . R e l a t i v e l y high tree^-to-tree v a r i a t i o n was noted. N e v e r t h e l e s s , s i m i l a r mean values were obtained f o r the p o p u l a t i o n ; Moss (107) a l s o found a s i m i l a r p a t t e r n . Barton and MacDonald ( 7 ) i n v e s t i g a t e d the p o t e n t i a l use of l o d g e p o l e pine needles as animal fodder supplements. They obtained an e s s e n t i a l o i l content of 0.7655 average i n winter and 0.54% i n summer; Good or poor growth s i t e s made l i t t l e d i f f e r e n c e i n needle chemical composition. L i p i d s from lodgepole pine t e c h n i c a l f o l i a g e , i . e . , f o l i a g e plus branches to a g u a r t e r - i n c h diameter, have not been s t u d i e d ; A d e t a i l e d study by Hannus (54) on l i p o p h i l i c e x t r a c t i v e s of Scots pine (Pinus s y l v e s t r i s L.) t e c h n i c a l f o l i a g e gives i n t e r e s t i n g i n f o r m a t i o n . He found a 12% petroleum ether s o l u b l e f r a c t i o n from the t e c h n i c a l f o l i a g e * with 1% of v o l a t i l e o i l s , 2.5% t r i g l y c e r i d e s , 1% s t e r y l e s t e r s * 1.1% r e s i n a c i d s and 1.9% d i t e r p e n e a l c o h o l s . Needles and twigs were found to have d i f f e r e n t composition; Therefore the e x t r a c t composition depended on r e l a t i v e amounts of needles and twigs. 2 S a p o n i f i c a t i o n 2;1 D e f i n i t i o n and Relevance to T h i s Study A major p a r t of t h i s t h e s i s i s devoted to e x t r a c t i o n of l i p i d s from bark and f o l i a g e ; T h e r e f o r e , i t i s p e r t i n e n t to review the r e a c t i o n mechanism. 14 What renders o l e o r e s i n s r e c o v e r a b l e as t a l l o i l i n the k r a f t p u l p i n g process i s s o l u b i l i z a t i o n of these hydrophobic l i p i d s i n hot a l k a l i n e cooking l i q u o r as sodium s a l t s and t h e i r subsequent behaviour i n s o l u t i o n . The c o n v e r s i o n i s c a l l e d s a p o n i f i c a t i o n . In the case of f r e e f a t t y a c i d s and r e s i n a c i d s , the r e a c t i o n simply i n v o l v e s n e u t r a l i z a t i o n of a c i d s with a strong base, i ; e * , sodium hydroxide. In the case of combined f a t t y a c i d e s t e r s or f a t s , s a p o n i f i c a t i o n r e f e r s to the process i n which h y d r o l y s i s of f a t t y a c i d t r i g l y c e r i d e s as c a t a l y z e d by sodium hydroxide y i e l d s g l y c e r o l and f r e e f a t t y a c i d s which then form soaps. In a broader context, other e s t e r components i n wood, such as a c e t a t e groups of h e m i c e l l u l o s e s , a l s o are s u b j e c t e d to s a p o n i f i c a t i o n under a l k a l i n e c o n d i t i o n s ; T h i s area was e x p l o r e d r e c e n t l y by E r i n s et a l . (40,41,52). H y d r o l y s i s of f a t s or o i l s i s g e n e r a l l y c a l l e d f a t - s p l i t t i n g . The net e f f e c t of f a t s p l i t t i n g i s a d d i t i o n of t h r e e moles of water to one mole of f a t which r e s u l t s i n t h r e e moles of f a t t y a c i d and one mole of g l y c e r o l . F a t - s p l i t t i n g i s a c c e l e r a t e d by the presence of v a r i o u s c a t a l y s t s ; M i n e r a l a c i d s , c e r t a i n metal oxides; s u l f o n a t e of phenyl s t e a r i c a c i d and l i p o l y t i c enzymes are commonly employed f o r such purpose. 2.2 Reaction Mechanism and K i n e t i c s As mentioned above, s a p o n i f i c a t i o n r e f e r s t o both n e u t r a l i z a t i o n and a l k a l i n e f a t s p l i t t i n g . In the former case, f a t t y a c i d s r e a c t with sodium hydroxide e x o t h e r m i c a l l y , g i v i n g o f f 9.5 cal/mole of heat and the r e a c t i o n proceeds very f a s t 1 5 (136). A l k a l i n e h y d r o l y s i s of f a t s , on the other hand* i s more complicated* Conceivably, the r e a c t i o n proceeds i n stages, l i b e r a t i n g f r e e f a t t y a c i d s from the t r i g l y c e r i d e e s t e r one a t a time. However, at any stage of the s a p o n i f i c a t i o n r e a c t i o n , the mono- and d i - g l y e r i d e c o n c e n t r a t i o n s were found to be n e g l e g i b l e (139). From s t u d i e s of simple e s t e r s , base-induced f a t h y d r o l y s i s seems to d i f f e r from other f a t - s p l i t t i n g r e a c t i o n s , i n t h a t the r e a c t i o n i s i n e f f e c t n o n - r e v e r s i b l e . The i n i t i a l s tep of the r e a c t i o n i s a d d i t i o n of hydroxide i o n t o the e l e c t r o n - d e f i c i e n t c a r b o n y l carbon. The i n t e r m e d i a t e anion formed may shed the hydroxide i o n and r e v e r t to the o r i g i n a l s t a t e or, by s p l i t t i n g f a t t y a c i d o f f . Once the a c i d i s formed, i t i s s t a b l i z e d by c o n v e r s i o n t o the c a r b o x y l a t e anion* Thus, the r e a c t i o n goes to completion i n the d i r e c t i o n of h y d r o l y s i s (33). The r e a c t i o n i s somewhat exothermic with ca. 58 cal/mole produced with s t e a r a t e t r i g l y c e r i d e (140). Braun and F i s c h e r (19) pointed out t h a t , c o n s i s t e n t with t h i s mechanism, f a c t o r s that weaken e l e c t r o p h i l i c i t y of the c arbonyl carbon or s p a t i a l l y block the c a r b o n y l group h i n d e r s a p o n i f i c a t i o n , as w e l l as a c i d e s t e r i f i c a t i o n . The r e a c t i o n phase of s a p o n i f i c a t i o n has been a c o n t r o v e r s i a l s u b j e c t f o r some time* E a r l i e r , s a p o n i f i c a t i o n was regarded as a heterogeneous or two-phase r e a c t i o n t h a t occurred e x c l u s i v e l y at the o i l - w a t e r i n t e r f a c e . There were c e r t a i n r e a c t i o n f e a t u r e s t h a t seemed to bear out t h i s view. For i n s t a n c e , substances t h a t promote e m u l s i f i c a t i o n tend to i n c r e a s e r e a c t i o n r a t e . A l s o , f a t s c o n t a i n i n g f a t t y a c i d soaps of high e m u l s i f y i n g power g e n e r a l l y s a p o n i f y f a s t e r (33). 16 S a p o n i f i c a t i o n r a t e p l o t t e d a g a i n s t time gave a sigmoid curve with slow i n d u c t i o n p e r i o d f o l l o w e d by r a p i d i n c r e a s e i n r a t e and f i n a l l y slowing again when completion was approached (140). B e r g e l l (11) f o l l o w e d the t r a d i t i o n a l two^-phase t h i n k i n g a t t r i b u t i n g the change i n r a t e to a phase i n v e r s i o n from l y e i n o i l to o i l i n l y e , with the ensuing i n t e n s i f i e d e m u l s i f i c a t i o n . McBain et a l . (101) i n 1929, s t u d i e d s a p o n i f i c a t i o n of 25 o i l s and f a t s using a hydrogen e l e c t r o d e . Rate d i f f e r e n c e s of two hundred f o l d were noted. They a t t r i b u t e d these d i f f e r e n c e s to v a r i a t i o n i n the degree of e m u l s i f i c a t i o n , which i m p l i e d a heterogeneous mechanism. Fats with r e l a t i v e l y low degree of u n s a t u r a t i o n were found to s a p o n i f y more r e a d i l y than h i g h l y unsaturated f a t s . But no r e l a t i o n appeared between s a p o n i f i -c a t i o n r a t e and a c i d molecular weight. In 1927 Lascaray (87) s t u d i e d the s a p o n i f i c a t i o n r e a c t i o n a c c o r d i n g to i n t e r f a c i a l s u r f a c e theory and formulated that s a p o n i f i c a t i o n i s a heterogeneous system. An i n t e r f a c i a l model gave r e s u l t s t h a t account f o r r e a c t i o n r a t e and f a t v a r i a t i o n f a c t o r s . By 1932 Smith (135) questioned t h i s orthodox view of s a p o n i f i c a t i o n on the b a s i s of the sudden d r a s t i c i n c r e a s e i n r e a c t i o n r a t e a f t e r the i n i t i a l slow i n d u c t i o n p e r i o d * I n t e r f a c i a l r e a c t i o n can not e x p l a i n a surge i n r e a c t i o n r a t e . Since i t was known t h a t both f a t t y a c i d and a l k a l i are s o l u b l e to some extent i n soap, he proposed t h a t the bulk of saponi-f i c a t i o n was homogeneous and o c c u r r e d i n a soap phase. This theory accounted f o r f a c t s i n c l u d i n g : a) A u t o c a t a l y t i c nature of s a p o n i f i c a t i o n ; b) Independence of s a p o n i f i c a t i o n v e l o c i t y from a l k a l i c o n c e n t r a t i o n ; c) Greater speed of s a p o n i f i c a t i o n when 17 potash i s used i n s t e a d of soda; d) A c c e l e r a t i o n e f f e c t s by adding s m a l l amounts of a l c o h o l ; and e) The great a c c e l e r a t i o n e f f e c t by adding soap when i t i s the only v a r i a b l e . The idea of homogeneous r e a c t i o n i s now g e n e r a l l y accepted. Two more recent s t u d i e s seem to have shaken the homogeneous r e a c t i o n s a p o n i f i c a t i o n theory, however. S a p o n i f i c a t i o n of the e s t e r polymer, poly ( v i n y l cinnamate) , and palm^seed o i l was s t u d i e d (73,117). The r e a c t i o n s were found to be second order, with homogeneous r e a c t i o n i n the beginning. When s u f f i c i e n t soap had formed, the r e a c t i o n became c a t a l y t i c second order hetero-geneous. Re a c t i o n temperature made some d i f f e r e n c e s i n the r e a c t i o n mechanism. At low temperatures, s a p o n i f i c a t i o n proceeded predominantly by a heterogeneous mechanism near the r e a c t o r w a l l , while f o r temperatures above 500C i t became a homogeneous thermal process. Most l i t e r a t u r e r e g a r d i n g s a p o n i f i c a t i o n r e a c t i o n s seems t o i n d i c a t e a second order r e a c t i o n * T h i s was the case when Ono (114) s t u d i e d f a t s a p o n i f i c a t i o n i n a homogeneous b e n z e n e / a l c o h o l i c KOH s o l u t i o n . Miyanami et a l * (106) used s a p o n i f i c a t i o n of a simple e s t e r , e t h y l a c e t a t e , by sodium hydroxide as a t y p i c a l second-order i r r e v e r s i b l e r e a c t i o n , and s t u d i e d a p p l i c a b i l i t y of a one-dimensional d i s p e r s i o n model to the r e a c t i o n . E r i n et a l . (40) found t h a t s a p o n i f i c a t i o n of e s t e r bonds i n birchwood with 5% ammonium hydroxide was a second order r e a c t i o n , as w e l l * 2.3 H y d r o l y s i s Reaction As maintained i n t h i s survey, s a p o n i f i c a t i o n and processes 18 o f f a t h y d r o l y s i s a r e c o n s i d e r e d t o f o l l o w d i f f e r e n t mechanisms (33.139) , t h e r e f o r e d i f f e r e n t r e a c t i o n k i n e t i c s . N e v e r t h e l e s s , some w o r k e r s have p r e s e n t e d them as a s i n g l e h y d r o l y t i c f u n c t i o n w h e r e i n t h e two t e r m s were used l o o s e l y i n an i n t e r c h a n g e a b l e way. In t h e complex r e a c t i o n c o n d i t i o n s p r e s e n t e d i n a k r a f t c o o k , i t i s v e r y l i k e l y t h a t s a p o n i f i c a t i o n o f v a r i o u s e s t e r bonds i n wood c o n s t i t u e n t s i s a c c o m p a n i e d by c o n c u r r e n t h y d r o l y s i s o f t h e f a t s and a c e t a t e s . A b r i e f s u r v e y o f f a t s p l i t t i n g mechanism i s p e r t i n e n t . I n 1930 L e d e r e r (92) p r e s e n t e d t h e i d e a t h a t c h e m i c a l e q u i l i b r i u m d u r i n g f a t s p l i t t i n g and s a p o n i f i c a t i o n f o l l o w e d t h e mass l a w : K = [ G ] [ S ] 3 / [ F ] [ W ] 3 [ 1 ] where, G, S, F, W r e p r e s e n t c o n c e n t r a t i o n s o f g l y c e r o l * f a t t y a c i d s o a p , f a t and w a t e r o r s o d i um h y d r o x i d e s o l u t i o n , r e s p e c t i v e l y , w h i l e K i s an e q u i l i b r i u m c o n s t a n t * The e q u a t i o n s u g g e s t s a s t o i c h i o m e t r i c c o r r e s p o n d e n c e * One i m p o r t a n t c h a r a c t e r i s t i c o f h y d r o l y s i s i s t h a t t h e r e a c t i o n i s r e v e r s i b l e and r e a c h e s e q u i l i b r i u m i n s t e a d o f g o i n g t o c o m p l e t i o n . The r e a c t i o n r a t e o f f a t - s p l i t t i n g i s i n d e p e n d e n t of t h e e q u i l i b r i u m and depends o n l y on c a t a l y s t c o n c e n t r a t i o n and t e m p e r a t u r e , w h i l e r e a c t i o n e q u i l i b r i u m depends on f a t t o w a t er r a t i o and e s p e c i a l l y c o n c e n t r a t i o n o f g l y c e r o l . T e m p e r a t u r e and c a t a l y s t have no e f f e c t a t a l l on e q u i l i b r i u m (89.140) . L a s c a r a y (38,89,90) was t h e f i r s t t o p o i n t o u t t h a t 19 f a t h y d r o l y s i s i s e s s e n i a l l y a homogeneous r e a c t i o n that proceeds i n an o i l phase. He observed t h a t i n the e a r l y stage of f a t h y d r o l y s i s , whether by a u t o c l a v e process or Twitchwell process, s t a b l e and f i n e l y d i s p e r s e d emulsions were formed. H y d r o l y s i s progressed slowly i n a heterogeneous r e a c t i o n * A f t e r a p e r i o d of time, the emulsions broke while the r e a c t i o n a c c e l e r a t e d s t r o n g l y . Reaction proceeded at constant r a t e t h e r e a f t e r u n t i l e q u i l i b r i u m was reached. The o v e r - a l l r e a c t i o n r a t e as a f u n c t i o n of time was a s i n u s o i d a l curve* C a t a l y s t s caused h y d r a t i o n and subsequent d i s p e r s i o n of water to the o i l phase, t h e r e f o r e i n c r e a s e d r e a c t i o n r a t e . Homogenous h y d r o l y s i s was a c t i v a t e d by hydrogen i o n s . The requirements f o r a good c a t a l y s t were: Strong s o l u b i l i t y i n f a t and weak s o l u b l i t y i n water, and; Molecules c o n t a i n i n g i o n s or f u n c t i o n a l groups which are s t r o n g l y hydrated and capable of l i b e r a t i n g hydrogen i o n s d i r e c t l y or i n d i r e c t l y ; Other workers (12) found t h a t c a t a l y t i c a c t i v i t y of soap was i n v e r s e l y p r o p o r t i o n a l to base s t r e n g t h of the metal hydroxide and p r o p o r t i o n a l to i t s water s o l u b i l i t y . Although M i l l s and McClain (104) s t i l l c o n s i d e r e d f a t - s p l i t t i n g a two-phase heterogeneous r e a c t i o n i n 1949* i t i s g e n e r a l l y r e c o g n i z e d now t h a t only minor s p l i t t i n g occurs at the o i l - w a t e r i n t e r f a c e and t h a t the r e a c t i o n i s e s s e n t i a l l y homogeneous and occurs through the a c t i o n of water d i s s o l v e d i n the o i l phase (140). Other workers subsequently confirmed Lascaray's observa-t i o n * Sturzenegger and Sturm (143) extended h y d r o l y s i s s t u d i e s to high temperatures (225 to 280°C). Although at such high temperature the f a t and water s o l u b i l i t y r e l a t i o n s h i p s are 20 c o n s i d e r a b l y d i f f e r e n t , they found t h a t the r e a c t i o n was homogeneous and t h a t r a t e was independent of the o i l - w a t e r r a t i o . H y d r o l y s i s showed no heat of r e a c t i o n between 150 to 280<>C, i n agreement with what Kaufmann and K e l l e r (74) had pointed out e a r l i e r , i * e . , that temperature independence of the h y d r o l y s i s e q u i l i b r i u m point i n d i c a t e d a zero heat of r e a c t i o n . K i n e t i c s s t u d i e s of f a t h y d r o l y s i s g e n e r a l l y i n d i c a t e a f i r s t order r e a c t i o n (143,144). Lascaray (90) examined the temperature c o e f f i c i e n t of the f a t h y d r o l y s i s r e a c t i o n * An i n c r e a s e of 10°C r a i s e d r e a c t i o n r a t e 1.2 to 1.5 times. For the g r e a t e r p a r t of the homogeneous r e a c t i o n , a temperature c o e f f i c i e n t of 2 t o 4, even up to 7, was noted* P h y s i c a l processes, such as d i s s o l u t i o n r a t e and d i f f u s i o n , had temperature c o e f f i c i e n t s of 1.3. The o v e r a l l f a t h y d r o l y s i s r a t e was, t h e r e f o r e , governed mainly by p h y s i c a l phenomena, e s p e c i a l l y d i f f u s i o n which u s u a l l y c o n t r o l s the r a t e of r e a c t i o n * Hence, study of r e a c t i o n k i n e t i c order i s f u t i l e . S ince the d i f f u s i o n equation has a form i d e n t i c a l to t h a t of a u n i m o l e c u l a r r e a c t i o n , the e x p r e s s i o n of an apparent f i r s t order r e a c t i o n w i l l always be obtained. More rec e n t s t u d i e s (12,13) tend to confirm t h i s view. K i n e t i c s of f a t h y d r o l y s i s depended on the c a t a l y t i c a c t i v i t y of reagent soap, the amount of c a t a l y s t and depth of process flow. The order of r e a c t i o n changes from zero order, which i s s p e c i f i c f o r the k i n e t i c area, to f i r s t order i n the d i f f u s i o n area, where most of the r e a c t i o n takes p l a c e . In f a t s p l i t t i n g , u n l i k e s a p o n i f i c a t i o n , there i s no apparent d i f f e r e n c e i n the r e a c t i o n r a t e s of s a t u r a t e d and 21 unsaturated f a t t y a c i d s ; At e q u i l i b r i u m about 18;3% of combined g l y c e r i d e s remain i n s o l u t i o n , u n l e s s the g l y c e r o l i s removed from r e a c t i o n . The r a t i o of mono-, d i - , and t r i g l y c e r i d e s was constant (108,142). M i l l s and McClain (104) found t h a t 18.5 to 20% of t a l l o w and 22 to 24% of coconut o i l were s t i l l u n s p l i t at the e q u i l i b r i u m p o i n t . The maximum degree of s p l i t t i n g was a l i n e a r f u n c t i o n of g l y c e r o l c o n c e n t r a t i o n i n the s o l u t i o n . 2.4 Some P r o p e r t i e s of Soaps T a l l o i l recovery i n the k r a f t process depends on e f f e c t i v e s e p a r a t i o n of soaps from black l i q u o r . The nature of soap i n aqueous s o l u t i o n , e s p e c i a l l y phase a s s o c i a t i o n o f the soap-water system, has trememdous importance i n e f f e c t i v e soap recovery. One o f the more s t r i k i n g c h a r a c t e r i s t i c s of f a t t y a c i d soaps i s t h e i r s p a r i n g s o l u b i l i t y i n water at room temperature. U s u a l l y only extremely d i l u t e s o l u t i o n s of sodium soaps above carbon c h a i n l e n g t h Cs can be made at room temperature; At higher temperature, however, sodium soaps are f r e e l y s o l u b l e i n water up t o an extent of 64%. T h i s property helps i n soap s e p a r a t i o n when black l i q u o r i s co o l e d , c o n c e n t r a t e d , or allowed to stand. The a l k a l i s a l t s of f a t t y a c i d s t h a t have soap c h a r a c t e r i s t i c s are l i m i t e d to c e r t a i n homologous s e r i e s of a l p h a t i c a c i d s . Below C 6 a c i d s the a l k a l i n e s a l t s have the us u a l p r o p e r t i e s of simple e l e c t r o l y t e s . At or above C 2 2 , the s o l u b i l i t y of a l k a l i s a l t s i s so l i m i t e d as to be p r a c t i c a l l y zero i n c o l d water (33). E a r l i e r works as summarized by McBain (100) made i t c l e a r 22 that there were some s p e c i e s of i o n i c aggregations i n d i l u t e soap s o l u t i o n s . E l e c t r i c a l c o n d u c t i v i t y of a moderately conc e n t r a t e d soap s o l u t i o n was much g r e a t e r than t o be expected from c r y s t a l l o i d a l m a t e r i a l content as e s t a b i l i s h e d by osmotic or f r e e z i n g - p o i n t depression methods. T h i s suggested that t h e r e were m u l t i p l e charged p a r t i c l e s . A l s o , as c o n c e n t r a t i o n of soap s o l u t i o n was i n c r e a s e d , m i g r a t i o n of the f a t t y a c i d r a d i c a l s i n c r e a s e d abnormally i n d i c a t i n g formation of r a t h e r high m o b i l i t y i o n i c aggregates. There are other p e c u l i a r i t i e s i n soap s o l u t i o n p h y s i c a l p r o p e r t i e s i n r e l a t i o n to c o n c e n t r a t i o n . At a c e r t a i n c r i t i c a l c o n c e n t r a t i o n the e q u i v a l e n t c o n d u c t i v i t y decreases s h a r p l y with i n c r e a s i n g c o n c e n t r a t i o n , t h e r e a f t e r passes a minimum and then rebounds s l o w l y . Near t h i s c r i t i c a l p o i n t , s o l u t i o n s u r f a c e and i n t e r f a c i a l t e n s i o n become minimal, while osmotic pressure r i s e begins t o slow down. D i s c o n t i n u i t i e s of d e n s i t y , v i s c o s i t y and r e f r a c t i v e i n d i c e s are a l s o observed. I t i s now agreed t h a t the c r i t i c a l c o n c e n t r a t i o n range corresponds to the beginning of m i c e l l a r , or l y o t r o p i c l i q u i d c r y s t a l l i n e a ggregation. Hence, i t i s c a l l e d c r i t i c a l m i c e l l e c o n c e n t r a t i o n (c;m;C;). U s u a l l y the poi n t i s determined by c o n d u c i t i v i t y measurements (139). The m i c e l l e s have c a p a b i l i t y of h o l d i n g a l i p o p h i l e substance i n s o l u t i o n between hydrocarbon chains d i r e c t e d toward the m i c e l l e i n t e r i o r ; T h i s i s the main mechanism by which an " u n s a p o n i f i a b l e " t a l l o i l f r a c t i o n i s recovered from black l i q u o r . The c r i t i c a l m i c e l l e c o n c e n t r a t i o n s f o r some r e s i n a c i d s and f a t t y a c i d s sodium soaps are 0.02 mole/1 and 0.001 to 0.002 mole/1, r e s p e c t i v e l y (6,78). 23 The s o l u b i l i t y c h a r a c t e r i s t i c of soaps r e f e r r e d to e a r l i e r i s commonly found among m i c e l l e - f o r m i n g c o l l o i d s . The s o l u b i l i t y versus temperature curve o f soaps showed a "normal" s o l u b i l i t y i n c r e a s e with i n c r e a s e temperature, then at a c e r t a i n point s o l u b i l i t y i n c r e a s e d tremendously over a short temperature i n t e r v a l . T h i s c o r r e l a t i o n between m i c e l l e formation and s o l u b i l i t y behavior of soap i n d i c a t e d t h a t l a r g e s c a l e m i c e l l e formation began when the tr u e s o l u b i l i t y of the unassociated soap molecules was exceeded (124,139). Below c.m.Ci the soap s o l u t i o n i s e s s e n t i a l l y an i s o t r o p i c s o l u t i o n . C r i t i c a l m i c e l l a r c o n c e n t r a t i o n decreases r e g u l a r l y with i n c r e a s e d chain l e n g t h of a homologous s e r i e s . Presence of e l e c t r o l y t e s may depress CiU.c; g r e a t l y , mainly due to concen-t r a t i o n of i o n s o p p o s i t e i n charge to the long c h a i n i o n s , i . e . , p o s i t i v e l y charged m e t a l l i c i o n s have t h i s s a l t e f f e c t toward f a t t y a c i d r a d i c a l s (27). The c o n c e n t r a t i o n of a m p h i p h i l i c molecules l i k e l i g n i n a l s o showed s i m i l a r e f f e c t s (126). Soap s u r f a c e a c t i v i t i e s a r i s e from dynamic e q u i l i b r i a between o r i e n t e d molecules or i o n s , f r e e molecules or ions and m i c e l l a r aggregates, with l i m i t by s o l u b i l i t y c o n s i d e r a t i o n s . Surface and i n t e r f a c i a l t e n s i o n of water showed s u b s t a n t i a l r e d u c t i o n when soap was d i s s o l v e d i n i t . The theory formulated by Harkins et a l * (55) and Langmuir (85) d e a l i n g with the phenomena of surface-bound unimolecular l a y e r s , v i z . molecular o r i e n t a t i o n at i n t e r f a c e s , provided e x p l a n a t i o n f o r the mechanism o f s u r f a c e a c t i v i t y . A d d i t i o n of e l e c t r o l y t e s t o a soap s o l u t i o n f u r t h e r lowered s u r f a c e and i n t e r f a c i a l t e n s i o n . M u l t i v a l e n t c a t i o n s had greater i n f l u e n c e than u n i v a l e n t c a t i o n s 24 at e q u i v a l e n t c o n c e n t r a t i o n s , while anion s p e c i e s had no e f f e c t on s u r f a c e a c t i v i t y . T h i s was thought to be due to r e d u c t i o n of mutual r e p u l s i o n between soap molecules by the e l e c t r o l y t e s , which permitted a g r e a t e r packing d e n s i t y (139). Aqueous s o l u t i o n s c o n t a i n i n g s u r f a c e a c t i v e l i q u i d c r y s t a l s tended to form " s t a t i c " or e q u i l i b r i u m s t a t e s with the bulk of the s o l u t i o n over a p e r i o d of time. Soap or other s u r f a c e a c t i v e agents tended to migrate and c o n c e n t r a t e at the surface* T h i s property i s v i t a l i n soap s e p a r a t i o n and foam s t a b i l i t y d u r i n g the t a l l o i l s e p a r a t i o n process (126) . The k r a f t soap m i c e l l a r s t r u c t u r e has been s t u d i e d e x t e n s i v e l y . I n d i r e c t evidence, such as X-ray d i f f r a c t i o n data, has i n f e r r e d t h a t s p h e r i c a l or l a m e l l a r s t r u c t u r e s are l i k e l y (58,98). Ekwall et a l . (34) demonstrated s e v e r a l d i f f e r e n t l y o t r o p i c l i g u i d c r y s t a l l i n e phases i n systems c o n t a i n i n g r e s i n a c i d s , f a t t y a c i d s and t h e i r soaps. Another study (79) found that a p o l y c y c l i c condensed molecule, such as r e s i n a c i d was l i k e l y t o form m i c e l l e s of n o n s p h e r i c a l d i s c shaped s t r u c t u r e . Roberts et a l . (126) c h a r a c t e r i z e d soaps separated from the soap tank of a k r a f t process as having a l a m e l l a r m i c e l l e s t r u c t u r e . Hence, f a c t o r s f a v o r i n g the formation of a l i q u i d c r y s t a l l i n e phase of l a m e l l a r s t r u c t u r e tended to maximize the amount of t a l l o i l soap. A m i c e l l a r s t r u c t u r e would a l s o s t a b i l i z e emulsions, however, a f t e r a c i d i f i c a t i o n t h a t converted s u l f a t e soap i n t o t a l l o i l , the e x i s t e n c e of a m i c e l l a r s t r u c t u r e i n the o i l phase would reduce o i l s e p a r a t i o n r a t e . 25 3 K r a f t P u l p i n g Process 3.1 K r a f t Pulping Process and Black L i q u o r E x t r a c t i o n K r a f t p u l p i n g i s a vast s u b j e c t by i t s e l f . E f f o r t s here w i l l c e n t e r on cooking v a r i a b l e s and r e a c t i o n k i n e t i c s , and not d e t a i l e d d i s c u s s i o n of the v a r i o u s chemical r e a c t i o n s . Although chemical composition and m o r p h o l o g i c a l p r o p e r t i e s of wood c h i p s are somewhat d i f f e r e n t from those of bark and f o l i a g e and e f f e c t s of v a r i a b l e s i n the processes may be q u i t e d i f f e r e n t , i t i s c o n c e i v a b l e t h a t e x t r a c t i o n of v a r i o u s t r e e r e s i d u e s with black l i q u o r i s s i m i l a r i n f u n c t i o n t o k r a f t cooking of wood. In order to assess BLE k i n e t i c s and v a r i a b l e s i t i s convenient t o draw upon the l a r g e body of knowledge alre a d y accumulated concerning the k i n e t i c s and v a r i a b l e s of k r a f t p u l p i n g . 3.1.1 Cooking L i g u o r and Chemical Balances The white l i g u o r used f o r k r a f t p u l p i n g c o n t a i n s the a c t i v e i n g r e d i e n t s of sodium hydroxide and sodium s u l f i d e with s m a l l amounts of other sodium s a l t s which are e s s e n t i a l l y i n e r t throughout the process. During d i g e s t i o n the a c t u a l e n t i t i e s that are thought to enter i n t o r e a c t i o n s with wood are hydroxide i o n s and h y d r o s u l f i d e i o n s . The l a t t e r come from h y d r o l y s i s of s u l f i d e i o n s , which u s u a l l y r e s u l t s i n one mole of h y d r o s u l f i d e i o n and one mole of hydroxide i o n per mole of sodium s u l f i d e . H y d r o s u l f i d e ions can be f u r t h e r hydrolyzed to hydrogen s u l f i d e and hydroxide i o n . However, under normal cooking c o n d i t i o n s , t h i s i s u n l i k e l y to happen. To account f o r the a l k a l i charge 26 a v a i l a b l e f o r p u l p i n g , c e r t a i n terms were developed* " A c t i v e a l k a l i " i s the sum of sodium hydroxide and sodium s u l f i d e charges c a l c u l a t e d as sodium e q u i v a l e n t and expressed as sodium oxide or hydroxide. Since h y d r o l y s i s c f sodium s u l f i d e only goes h a l f way under the high pH cooking c o n d i t i o n , as mentioned above, the a c t u a l amount of a l k a l i a v a i l a b l e f o r p u l p i n g i s c l o s e r t o the concept of " e f f e c t i v e a l k a l i " > which counts the hydroxide c o n c e n t r a t i o n as mole per mole of sodium hydroxide and one-half mole per mole of sodium s u l f i d e . A t y p i c a l white l i q u o r c o n t a i n s around 1 mole or 40 g/1 of sodium hydroxide and 30% s u l f i d i t y , or 0.2 mole of sodium s u l f i d e . The pH of white l i g u o r i s i n the order of 14, so i s not e a s i l y or a c c u r a t e l y read. Reactions of a l k a l i with the wood carbohydrate f r a c t i o n are mostly u n d e s i r a b l e as they lower the y i e l d . However, s i n c e d e l i g n i f i c a t i o n needs high temperature and proceeds more sl o w l y than some of the carbohydrate r e a c t i o n s , such r e a c t i o n i s unavoidable and during the k r a f t cook a l k a l i i s consumed by p e e l i n g r e a c t i o n s with carbohydrates. T h i s accounts f o r n e a r l y two-thirds of the a l k a l i consumption and roughly corresponds to about 1.6 moles of a c i d s per mole hexose u n i t ; D e l i g n i f i c a t i o n i s r e s p o n s i b l e f o r o n l y about a q u a r t e r of the a l k a l i consumption. Here a l k a l i i s used mostly i n n e u t r a l i z i n g l i g n i n p h e n o l i c groups. H y d r o l y s i s of a c e t y l groups takes up the remainder of the a l k a l i used. Y l l n e r et a l . (158) showed that at temperatures below 100°C very l i t t l e d i s s o l u t i o n t a k e s p l a c e . Most of the r e a c t i o n s took p l a c e a f t e r temperature had reached 125°C. At the end of the cook, i n a d d i t i o n to l i g n i n d i s s o l u t i o n , xylan and mannan of the h e m i c e l l u l o s e f r a c t i o n 27 s u f f e r e d t h e most d e g r a d a t i o n w h i l e g l u c a n and g a l a c t a n were more r e s i s t a n t t o a l k a l i . Degree o f l i g n i n , x y l a n and g l u c a n d i s s o l u t i o n i s d e p e n d e n t on a l k a l i n i t y , i . e . , t h e d e g r a d a t i o n r e a c t i o n r a t e i s a f f e c t e d by h y d r o x i d e i o n c o n c e n t r a t i o n . Mannan d i s s o l u t i o n i s f a i r l y i n d e p e n d e n t o f t h e a l k a l i n i t y ; C o n s u m p t i o n o f a l k a l i c a u s e s c h a n g e s i n c o o k i n g l i g u o r pH. T h i s i n f l u e n c e s t h e f i n a l r e s u l t s i n some ways a s t h e h y d r o -s u l f i d e i o n i z a t i o n s t a t e i s a f f e c t e d and r e p r e c i p i t a t i o n o f v a r i o u s d i s s o l v e d c a r b o h y d r a t e s , l i g n i n and some c h r o m o p h o r e s may o c c u r . S i n c e a l k a l i c o n s u m p t i o n i s p r o p o r t i o n a l t o d i s -s o l u t i o n o f s u b s t a n c e s , upon c o o k i n g t o a c o n s t a n t y i e l d t h e l i q u o r pH t o w a r d t h e end o f the cook depends on t h e i n i t i a l a l k a l i c h a r g e (130). The s u l f u r c o n s u m p t i o n d u r i n g t h e cook amounts t o o n e - t h i r d o f t h e s u l f u r c h a r g e a t a t y p i c a l 30% s u l f i d i t y (0.2 mole s o d i u m h y d r o x i d e ) . B a s e d on t h i s a b o u t 2 t o 3.5% o f t h e s u l f u r s h o u l d be o r g a n i c a l l y combined w i t h t h e k r a f t l i g n i n ; T h e r e i s some d i s c r e p a n c y between t h e t o t a l s u l f i d e c o n s u m p t i o n and t h a t f o u n d i n k r a f t l i g n i n , which i s i n t h e o r d e r o f 1 t o 3%, o r 0.1 t o 0.2 S p e r l i g n i n monomer ( 4 3 , 4 4 ) . T h i s i s p r o b a b l y due t o t h e p r e s e n c e 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 f r a c t i o n s o r m o l e c u l a r f r a g m e n t s o f h i g h s u l f u r c o n t e n t which a r e n o t p r e c i p i t a b l e by a c i d i f i c a t i o n ( 1 3 0 ) . The s m a l l q u a n t i t y o f s u l f u r i n k r a f t l i g n i n a s compared w i t h s u l f i t e l i g n i n s r e i n f o r c e s t h e o p i n i o n t h a t t h e r o l e o f h y d r o s u l f i d e i o n i n t h e k r a f t cook i s p r o b a b l y c a t a l y t i c . H y d r o s u l f i d e i o n i s t h o u g h t t o add t o l i g n i n d u r i n g t h e p r o c e s s and e v e n t u a l l y s p l i t o f f a g a i n t h r o u g h t h e a c t i o n o f a l k a l i (37,66). 28 The consumption of chemical during k r a f t cooking has l i t t l e to do with chemical balance. Because the nature of the recovery system i s such t h a t whatever i s i n the l i g u o r stream, i n c l u d i n g the wood f r a c t i o n s , g e n e r a l l y goes to the furnace* Sodium l o s s occurs l a r g e l y i n the washing o p e r a t i o n a f t e r the cook* There i s r e l a t i v e l y l i t t l e sodium l o s t i n e v a p o r a t i o n and the recovery furnace. S u l f u r l o s s through r e l i e f gas i s r e l a t i v e l y s m a l l , but i s higher as t o t a l reduced s u l f u r (TRS) i n e v a p o r a t i o n and recovery furnace stages (15). To make up these s u l f u r l o s s e s , s a l t cake (sodium s u l f a t e ) i s u s u a l l y added during the r e c y c l i n g process. In the case of high s u l f u r l o s s , a d d i t i o n of elemental s u l f u r t o the white l i g u o r or the furnace (28,151), or o x i d a t i o n of black l i g u o r (109,110) to s t a b i l i z e s u l f u r compounds can remedy the problem. 3.2 K i n e t i c s and Cooking V a r i a b l e s E l u c i d a t i o n of the k r a f t or any wood pu l p i n g mechanism i s complicated by the p h y s i c a l and chemical nature of wood and heterogeneous nature of the numerous r e a c t i o n s underway. The primary purpose of p u l p i n g i s to remove l i g n i n and l i b e r a t e p o l y s a c c h a r i d e f i b r e s k e l e t o n s . T h e r e f o r e , study of mechanism i s n e c e s s a r i l y concerned with d e l i g n i f i c a t i o n r e a c t i o n s . Lack of exact knowledge i n v a r i o u s aspects of l i g n i n c hemistry h i n d e r s a d i r e c t t h e o r e t i c a l approach to the problem. The r e s e a r c h methods u s u a l l y employed are based on s t u d y i n g e f f e c t s o f cooking v a r i a b l e s , such as time, temperature, l i q u o r c h a r a c t e r i s t i c s and c h i p dimension* I n t e r p r e t a t i o n of these r e s u l t s by k i n e t i c s provides some i n s i g h t i n t o a c t u a l mechanisms o f . t h e pulping 29 process. 3.2.1 Time and Temperature E f f e c t s Since the complex r e a c t i o n s o c c u r r i n g at the wood and p u l p i n g l i q u o r i n t e r f a c e s are heterogeneous, i t i s erroneous to t r e a t p u l p i n g k i n e t i c s as a homogeneous r e a c t i o n i n s o l u t i o n (81,86). N e v e r t h e l e s s , during major p e r i o d s of the k r a f t cook the o v e r a l l r e a c t i o n r a t e can be approximated as a f i r s t - o r d e r r e a c t i o n . A r r h e n i u s ( 5 ) i n 1926 noted a f i r s t order r e a c t i o n between wood and l y e . In a l k a l i n e p u l p i n g the l a s t 2 to 3% of r e s i d u a l l i g n i n i s more d i f f i c u l t t o remove and f o l l o w s a d i f f e r e n t r e a c t i o n mechanism; Laroque and Maass (86) gave the f o l l o w i n g f i r s t - o r d e r eguation, which f i t s l i n e a r l y most d e l i g n i f i c a t i o n r e a c t i o n s : -dL/dt = k (Lo - L) , or k = 1/t In (Lo/L) [ 2 ] where: k i s the r a t e constant, t i s time, L i s f i n a l l i g n i n content and Lo i s the i n i t i a l l i g n i n content. M i t c h e l l and Yorston (105) p o s t u l a t e d that the l a s t l i g n i n i s h e l d i n the i n t e r i o r of the c e l l w a l l . I t s r e l a t i v e l y l a r g e p a r t i c l e s i z e c o u l d h i n d e r outward d i f f u s i o n , hence i n v o l v e a slower r a t e of d e l i g n i f i c a t i o n . Laroque and Maass (86) i n t e r p r e t e d temperature data of a l k a l i n e d e l i g n i f i c a t i o n on the b a s i s of the A rrhenius equation as: In k = B -A/T [3a] where: k i s the r a t e constant, A and B are s p e c i f i c constants 30 and T i s temperature i n degrees K e l v i n . Upon s e t t i n g B = l n z and A = E/R, where Z and E are the new s p e c i f i c c o n s t a n t s , and R i s the gas c o n s t a n t , the equation becomes: In k = InZ - E/RT, or k = Zexp (-E/RT) [3b] From t h i s equation an a c t i v a t i o n energy of 32,000 cal/mole i s found f o r a l k a l i n e or soda cooking of wood* K u l k a r n i and Nolan (81) f o l l o w e d the same c a l c u l a t i o n s and gave a value of 24,000 cal/mole as a c t i v a t i o n energy f o r k r a f t p u l p i n g at 25% s u l f i d i t y ; The r a t e of p u l p i n g i s dependent on temperature, i n t h a t an i n c r e a s e i n maximum temperature of 10°C would roughly double the r e a c t i o n r a t e i n the k r a f t cook (141,152). Based on the assumption that a l k a l i n e p u l p i n g i s a f i r s t - o r d e r r e a c t i o n , and using r e s u l t s of s e v e r a l l a b o r a t o r y cooks, F e l t o n (42) was able to estimate v a l u e s f o r the r e a c t i o n r a t e . The i n t e g r a t e d r a t e value over time then r e p r e s e n t s a complete cooking c y c l e through a s i n g l e value c a l l e d " b o i l i n g u n i t s " . Vroom (152) made a profound impact by i n t r o d u c i n g the concept of " H - f a c t o r " f o r k r a f t p u l p i n g , which combines time-temperature i n t o a s i n g l e v a r i a b l e * The same Arrhenius equation presented above by Laroque and Maass (86), as w e l l as values f o r constants e s t a b l i s h e d by them were used* An H - f a c t o r of u n i t y was a r b i t r a r i l y set f o r a p u l p i n g e f f e c t of one hour at 100°C. The r e l a t i v e r a t e at any other temperature-time combination can be d e r i v e d e a s i l y . In p r a c t i c e the cooking to a common H - f a c t o r value under d i f f e r e n t cooking schemes giv e s comparable r e s u l t s i f other v a r i a b l e s are h e l d constant. I t i s 31 e s p e c i a l l y u s e f u l to the i n d u s t r y i n a d j u s t i n g cooking c y c l e s when o p e r a t i o n a l d i f f i c u l t i e s d i c t a t e a change from normal time and temperature. Some m o d i f i c a t i o n of H-factor i s needed before i t can be adopted f o r soda p u l p i n g due to d e v i a t i o n from the H-factor behavior. More r e c e n t l y , Hatton (61) r e l a t e d k r a f t pulp y i e l d (Y) or r e s i d u a l l i g n i n content i n d i c e s (permangnante number or Kappa number) to the t o t a l p h y s i c a l and chemical energy i n p u t of the pro c c e s s . He used a l i n e a r e x p r e s s i o n which i n c l u d e d Vroom's H-factor (H) concept and e f f e c t i v e a l k a l i (EA) as v a r i a b l e s . A s p e c i a l e x p o n e n t i a l term (n) was e s t a b l i s h e d f o r v a r i o u s t r e e s p e c i e s . The equation has the form o f : Y = A - B[ (logH) (EA) n ] [ 4 ] where A, B are constants* For c o n i f e r o u s woods (n) i s i n the range of 0.35 t o 0.41, while t r e m b l i n g aspen has a (n) value of 0.76. T h i s was thought to r e l a t e to d i f f e r e n t l i g n i n to carbohydrate r a t i o s between softwood and hardwood. The value of (n) i n d i c a t e s the slope of the f u n c t i o n . 3.2.2 L i q u o r C o n c e n t r a t i o n and Composition Laroque and Maass (86) s t u d i e d the e f f e c t o f d i f f e r e n t a l k a l i s p e c i e s on a l k a l i n e d e l i g n i f i c a t i o n . At e q u i v a l e n t molar c o n c e n t r a t i o n , r a t e of r e a c t i o n i n c r e a s e d i n the order: LiOH, NaOH and KOH* Changing the s o l v e n t from water t o methanol and eth a n o l a l s o i n c r e a s e d the r a t e * These phenomena suggested t h a t decreasing s o l v a t i o n and i n c r e a s i n g m o b i l i t y of the i o n s help p e n e t r a t i o n by the a l k a l i * Rate constants were a l s o found to 32 i n c r e a s e p r o p o r t i o n a l l y with a l k a l i c o n c e n t r a t i o n of the l i g u o r . K u l k a r n i and Nolan (81) i n t h e i r k r a f t mechanism study a l s o presented evidence of l i n e a r dependency of the r a t e constant to cooking l i g u o r c o n c e n t r a t i o n with a constant s u l f i d i t y and when temperature of the cook i s i n v a r i a t e . Higher chemical charge, t h e r e f o r e , may provide some advantage i n minimizing the liguor-to-wood r a t i o . However, high a l k a l i charge a l s o tends to lower y i e l d a t constant degree of d e l i g n i f i c a t i o n due to i n c r e a s e d s o l u b i l i z a t i o n of carbohydrates (130). S u l f i d e i n cooking l i g u o r has the b e n e f i c i a l e f f e c t of lowering a c t i v a t i o n energy f o r the r e a c t i o n , i . e . , 24,000 cal/mole f o r k r a f t cooking vs. 32,000 cal/mole f o r a soda cook. This a c c e l e r a t e s the r e a c t i o n a c c o r d i n g l y . S e v e r a l s t u d i e s (20,42,43) have demonstrated the e f f e c t of s u l f i d e on the r e a c t i o n r a t e . Bray and Martin (20) noted that the s u l f i d e c o n t r i b u t i o n i s most c r i t i c a l i n the low s u l f i d i t y range. For most woods higher s u l f i d i t y than 30% appears to c o n t r i b u t e very l i t t l e t o r e a c t i o n r a t e . The c r i t i c a l c o n c e n t r a t i o n or the i n f l e c t i o n p o i n t of the curve i s around 15% s u l f i d i t y . The two cooking chemical i n g r e d i e n t s , sodium hydroxide and h y d r o s u l f i d e , are considered to have independent f u n c t i o n s . The concept of e f f e c t i v e a l k a l i as used i n p r a c t i c e i n d i c a t e s there are c e r t a i n i n t e r a c t i o n s between c o n c e n t r a t i o n and behavior of the two chemicals. Most r e c e n t l y Tasman (148) s t u d i e d the r o l e of sodium s u l f i d e and expanded the e f f o r t s of Hatton by i n c o r p o r a t i n g s u l f i d i t y (S) i n t o the e f f e c t i v e a l k a l i (EA) v a r i a b l e . Data of Legg and Hart (93) showed t h a t s u l f i d i t y , as w e l l as e f f e c t i v e 33 a l k a l i , a f f e c t e d the s l o p e and i n t e r c e p t of y i e l d as a f u n c t i o n of r a t e . Upon cooking to a constant degree of d e l i g n i f i c a t i o n , a l l woods showed a decrease i n H - f a c t o r requirement with i n c r e a s i n g s u l f i d i t y at a constant e f f e c t i v e a l k a l i charge* T h i s i n d i c a t e d a strong i n t e r a c t i o n between these v a r i a b l e s as to t h e i r i n f l u e n c e on the r e a c t i o n r a t e . An e x p r e s s i o n c o n t a i n i n g the term EA l o g s appeared to i n t e g r a t e the e f f e c t of l i q u o r composition i n t o a s i n g l e charge v a r i a b l e * Results of other e a r l i e r work (30,125) tend t o support t h i s i d e a . T h i s i s e s p e c i a l l y h e l p f u l when low EA and h i g h S cooking c o n d i t i o n s are employed, which seem to i n c r e a s e y i e l d of some woods and provide higher pulp v i s c o s i t y and s t r e n g t h p r o p e r t i e s (30,93). 3.2.3 Other Cooking V a r i a b l e s Most of the other well-known cooking v a r i a b l e s i n the k r a f t process, such as wood source, c h i p dimension, and pretreatments have r a t h e r l i m i t e d importance to the present study. The r a t e of a l k a l i n e d e l i g n i f i c a t i c n proceeds f a s t e r f o r hardwood than softwood* Greater a c c e s s i b i l i t y of the wood s t r u c t u r e , l e s s tendency f o r the hardwood l i g n i n t o undergo condensation and e s p e c i a l l y lower l i g n i n content to begin with are probable reasons. Laroque and Maass (86) noted i n t h e i r c l a s s i c a l k a l i n e d e l i g n i f i c a t i o n study that wood s p e c i f i c g r a v i t y made l i t t l e d i f f e r e n c e i n d e l i g n i f i c a t i o n r a t e * The i n f e r e n c e they drew was that e i t h e r cooking l i q u o r completely permeated the wood substance or more l i k e l y , the area of the r e a c t i o n i n t e r f a c e was p r o p o r t i o n a l to l i g n i n content i n wood. 34 The g e n e r a l l y accepted view i s that a l k a l i n e p u l p i n g l i g u o r s are capable of p e n e t r a t i n g wood i n a l l d i r e c t i o n s . Hence, p e n e t r a t i o n e f f e c t s have l e s s b e a r i n g on a l k a l i n e p u l p i n g than other p u l p i n g processes; Chip t h i c k n e s s appears to be the most c r i t i c a l dimension i n k r a f t p u l p i n g (57,61a). K u l k a r n i and Nolan (81) pulped 2-inch wood cubes and suggested that i n c o n t r a s t to the p e n e t r a t i o n theory, d e l i g n i f i c a t i o n i s accomplished by a r e a c t i o n i n t e r f a c e which moves toward the i n t e r i o r of the c h i p . A l k a l i does not penet r a t e a p p r e c i a b l y ahead of t h i s i n t e r f a c e . A l l the s t u d i e s on k r a f t p u l p i n g k i n e t i c s were based on r e s i d u a l l i g n i n c o n c e n t r a t i o n ; One study (25) based k i n e t i c s on the other r e a c t a n t , i . e . , the a l k a l i , and found a second-order r e a c t i o n f o r k r a f t p u l p i n g . Chip s i z e s were found t o a f f e c t r e a c t i o n a c t i v a t i o n energies and mechanism g r e a t l y ; The r e a c t i o n was . c o n t r o l l e d by k i n e t i c s f o r c h i p s of 1,5mm, and by d i f f u s i o n f o r c h i p s o f 20mm. 3.3 K r a f t Recovery Systems The scheme of black l i g u o r e x t r a c t i o n (BLE) would have tremendous impact on the c o n v e n t i o n a l k r a f t l i g u o r flow. E s p e c i a l l y a f f e c t i n g the l i g u o r r e g e n e r a t i o n c y c l e . Thus, i t seems u s e f u l t o review k r a f t recovery systems and the p o s s i b l e a l t e r n a t i v e s to the c u r r e n t systems. Rydholm (131) c o n s i d e r e d t h a t a complete l i g u o r p r e p a r a t i o n c y c l e i n v o l v e s : 1) Evaporation of waste l i g u o r ; 2) Combustion of waste l i g u o r ; 3) Recovery of i n o r g a n i c chemicals; 4) P r e p a r a t i o n of cooking l i g u o r ; and 5) Manufacture of by-products. Grace 35 (51), from a s l i g h t l y d i f f e r e n t p e r s p e c t i v e * o u t l i n e d seven major o p e r a t i o n s i n the k r a f t recovery system. They are: 1) Formation o f NaOH; 2) Formation of sodium s u l f i d e ; 3) Combustion of o r g a n i c substance; 4) Separation of m a t e r i a l s ; 5) Removal of water; 6) By-product recovery; and 7) Energy r e c o v e r y . Most of these o p e r a t i o n s i n t e r a c t with BLE e x t r a c t i o n scheme. B r i e f l y , l i g u o r flow i n the c o n v e n t i o n a l k r a f t recovery c y c l e s t a r t s with weak black l i g u o r , u s u a l l y of 15 to 20% s o l i d content as r e c e i v e d from brown stock washers. A f t e r passing through m u l t i p l e - e f f e c t s e v a p o r a t i o n s t a t i o n s a s o l i d content of 55 to 60% i s a t t a i n e d . Sometimes a heavy black l i g u o r o x i d a t i o n o p e r a t i o n i s c a r r i e d out at t h i s stage, or at an e a r l i e r weak black l i g u o r stage, to s t a b i l i z e the s u l f u r components. F u r t h e r e v a p o r a t i o n r e q u i r e s the use of cascade or cyclone evaporators to achieve a f i n a l l i q u o r c o n c e n t r a t i o n of 60 to 75% s o l i d s . The v i s c o u s l i q u o r i s then sprayed through n o z z l e s i n t o the re c o v e r y furnace. Organic substances are burned and most of the sodium and s u l f u r components are converted i n t o sodium carbonate and sodium s u l f i d e . D i s s o l u t i o n of the smelt i n water generates green l i g u o r . Upon c a u s t i c i z i n g with calcium hydroxide, the white l i g u o r cooking i n g r e d i e n t s are regenerated* The most important t e c h n i c a l c o n s i d e r a t i o n s i n regard to a c t i v e cooking chemicals, are fo r m a t i o n cf sodium hydroxide and sodium s u l f i d e . 3.3.1 Sodium C y c l e and Options The most common means of o b t a i n i n g sodium hydroxide from black l i g u o r i s c a u s t i c i z i n g with calcium hydroxide as mentioned 36 above. A l t e r n a t i v e l y , f e r r i c oxide can be used t o r e a c t with sodium carbonate at e l e v a t e d temperature to form sodium f e r r a t e and l i b e r a t e carbon d i o x i d e . Sodium f e r r a t e r e a c t s with water t o give NaOH and regenerate the f e r r i c oxide* C a u s t i c can be produced d i r e c t l y by e l e c t r o l y s i s . The most important source of commercial NaOH i s through e l e c t r o l y s i s o f sodium c h l o r i d e s o l u t i o n . Kennedy and Je r n i g a n (76) patented a process of e l e c t r o l y z i n g black l i g u o r to get p r a c t i c a l l y pure NaOH s o l u t i o n i n the cathode compartment and l i g n i n d e p o s i t s on the anode. Russian s t u d i e s have examined the p o s s i b i l i t y of e l e c t r o d i a l y s i s with ion-exchange membranes (122) and an e l e c t r o l y t i c process (50) to recover sodium. Both processes have the advantage of r e c o v e r i n g l a r g e g u a n t i t i e s of organic m a t e r i a l s f o r chemical p r o c e s s i n g . In the former process, a n i o n i c or n e u t r a l (cellophane) membranes were used* The sodium recovery r a t e was 85%. For each part of sodium hydroxide recovered* 1.5 p a r t s of a l k a l i l i g n i n was a l s o obtained. Among some p o s s i b l e c o n f i g u r a t i o n s , a b a r r i e r c e l l package assembly without d i r e c t c o n t a c t of the membrane with black l i g u o r was the most e f f e c t i v e . For concentrated sodium s a l t s a m u l t i p l e stage system with graded c u r r e n t d e n s i t y and low r a t i o of br i n e to d i a l y z a t e c o n c e n t r a t i o n gave the best r e s u l t . The e l e c t r o l y s i s method had s i m i l a r setup as t h a t of a c o n v e n t i o n a l sodium c h l o r i d e e l e c t r o l y s i s c e l l * T h i s c o n s i s t s of a compartmentalized trough using a l a y e r of mercury at the bottom as a cathode. Sodium i o n s p i c k up e l e c t r o n s , amalgamate with the mercury and are t r a n s p o r t e d t o the other compartment, whereupon contact with 37 w a t e r r e g e n e r a t e s sodium h y d r o x i d e . A sodium r e c o v e r y r a t e o f 98-99% i s c l a i m e d . Power c o n s u m p t i o n a t 3.43 kw-hr/kg a l k a l i r e c o v e r e d i s much l e s s t h a n t h a t needed f o r t h e f i r s t s t a g e e v a p o r a t i o n o f b l a c k l i g u o r i n t h e c o n v e n t i o n a l k r a f t r e c o v e r y p r o c e s s . O r g a n i c s u b s t a n c e s s e p a r a t e d d u r i n g t h e e l e c t r o l y s i s a r e r e c o v e r a b l e . However, t h e m a j o r p r o b l e m i s t h a t s o d i um s u l f i d e has t o be t r e a t e d i n d e p e n d e n t l y and e l e c t r i c a l e n e r g y i s r e g u i r e d . 3.3.2 S u l f u r C y c l e and O p t i o n s The c o n v e n t i o n a l means o f f o r m i n g sodium s u l f i d e i s t o s u b j e c t b l a c k l i g u o r s o l i d s t o a h i g h t e m p e r a t u r e r e d u c i n g e n v i r o n m e n t . The e x o t h e r m i c r e a c t i o n o f c h a n g i n g s o d i um s u l f a t e t o s u l f i d e r e q u i r e s t e m p e r a t u r e s above 650OC, o t h e r w i s e t h e t h e r m o d y n a m i c e q u i l i b r i u m f a v o r s f o r m a t i o n o f h y d r o g e n s u l f i d e o v e r s o d i u m s u l f i d e . A l s o , t h e s u l f i d e i s n o t a s t a b l e f o r m . I t has s t r o n g t e n d e n c y t o o x i d i z e , e s p e c i a l l y a t t h e h i g h t e m p e r a t u r e i n v o l v e d . A s t r o n g r e d u c i n g c o n d i t i o n i s t h u s i m p e r a t i v e . The d e l i c a t e c h e m i c a l b a l a n c e under r e c o v e r y f u r n a c e c o n d i t i o n s has been summarized by Bauer and D o r l a n d ( 1 0 ) . The o n l y o t h e r o p t i o n f o r s u l f i d e r e g e n e r a t i o n , i n s t e a d o f r i g o r o u s r e c o v e r y f u r n a c e c o n d i t i o n s , i s t o d i s s o l v e h y d r o g e n s u l f i d e g a s d i r e c t l y i n t o c a u s t i c s o l u t i o n . T h i s h a s t h e p o t e n t i a l p r o b l e m o f c a r b o n d i o x i d e o r sodium c a r b o n a t e i n t e r -f e r e n c e w h i c h h i n d e r s t h e h y d r o g e n s u l f i d e d i s s o l u t i o n ( 5 1 ) . P r a h a c (123) p o i n t e d o u t t h a t t h e r a t h e r l i m i t e d o p t i o n s i n t h e s u l f u r r e c o v e r y c y c l e , i . e . , t h e r e q u i r e m e n t o f sodium s u l f a t e r e d u c t i o n t o e i t h e r sodium s u l f i d e o r h y d r o g e n s u l f i d e , 38 as w e l l as the d e l i c a t e s u l f u r balance problem, were the most c r u c i a l f a c t o r i n judging the values of an a l t e r n a t i v e system to the c o n v e n t i o n a l furnace. 3.3.3 Developments i n A l t e r n a t i v e K r a f t Recovery System The almost u n i v e r s a l adoption of the c u r r e n t k r a f t r e c o v e r y process s t i l l i n c l u d e s the Tomlinson type furnace i n t r o d u c e d about 50 years ago. The l a c k of change over these years r e f l e c t s the g e n e r a l s a t i s f a c t i o n with the system. I t o f f e r s smooth and r e l a t i v e l y t r o u b l e - f r e e o p e r a t i o n and combustion o f organic m a t e r i a l i n the black l i g u o r stream p r o v i d e s energy f o r the system t o be mostly s e l f - s u f f i c i e n t . Wrist (157) p o i n t e d out t h a t continued dominance of the k r a f t p u l p i n g process means t h a t a l k a l i chemical recovery systems w i l l be needed f o r a long time to come. Improvements are needed to meet i n c r e a s i n g demands as to energy, economic, environmental and s a f e t y c o n s i d e r a t i o n s : The f o l l o w i n g problems and trends have become apparent: 1) Economic c o n s i d e r a t i o n s l e a d toward the use o f a s i n g l e , v e r y l a r g e b o i l e r , which makes the process s e n s i t i v e t o b o i l e r outage; 2) E s c a l a t i n g c o s t s of recovery system i n s t a l l a t i o n s are caused by environmental p r o t e c t i o n measures and i n f l a t i o n ; 3) The p o t e n t i a l of smelt-water e x p l o s i o n s s t i l l plagues the system; 4) Environmental r e g u l a t i o n s l i m i t b o i l e r design and c a p a c i t y ; 5) Higher e x t e r n a l f u e l c o s t s f o r c e maximizing of energy r e c o v e r y c a p a c i t y ; and 39 6) Bleach p l a n t chemical recovery adds a burden and new t e c h n i c a l problems t c the c u r r e n t system. There are i n c e n t i v e s to look f o r a l t e r n a t i v e s to the c u r r e n t system. C e r t a i n progress has been made i n recent y e a r s , but most a l t e r n a t i v e s being examined are now onl y a t the s m a l l s c a l e experimental stage. The f u l l impact of these i n n o v a t i o n s i s yet t o come. Some of the proposed a l t e r n a t i v e k r a f t recovery systems i n v o l v e use of new p r i n c i p a l s . These i n c l u d e h y d r o p y r o l y s i s , p y r o l y s i s and g a s i f i c a t i o n . Most of the systems are based on p y r o l y s i s / g a s i f i c a t i o n t e c h n o l o g i e s . The use of a cyclone g a s i f i e r or f l u i d i z e d bed furnace adds other v a r i a t i o n s . One p i l o t p l a n t a l r e a d y i n op e r a t i o n i s the St. Regis h y d r o p y r o l y s i s p l a n t . The o p e r a t i o n t r e a t s black l i g u o r under heat and pressure i n the absence of oxygen* Organic substances are decomposed and o x i d i z e d s u l f u r i s reduced t o the s u l f i d e form. The f i n a l products i n c l u d e a combustible gas c o n t a i n i n g some s u l f u r , a sodium f r e e carbonaceous char which can be burned i n a c o n v e n t i o n a l power b o i l e r and an agueous stream c o n t a i n i n g most of the s u l f u r and sodium which can be c a u s t i c i z e d and used as white l i g u o r (111). Although some a l t e r n a t i v e methods o f f e r improved energy e f f i c i e n c y and most g i v e good sodium recovery* the present system i s s t i l l the most e f f e c t i v e i n s u l f u r r e c o v e r y . Some p e r i p h e r a l m o d i f i c a t i o n s of the c o n v e n t i o n a l system have taken p l a c e . Conversion of b o i l e r s f o r the burning of bark and other r e s i d u e s i s one such i n n o v a t i o n (153). Most recovery b o i l e r s have l a r g e furnaces f o r the amount of steam produced and 40 wide-spaced b o i l e r tubes. These f e a t u r e s are advantageous i n burning wood r e f u s e , and the c o s t of conversion i s about h a l f the c o s t of a new wood r e f u s e - f i r e d u n i t . There i s a l s o development of an annular type r e f u s e burner (72), which allows i n p u t of green bark and hogged f u e l from the c e n t r a l c y l i n d e r by downward screw f e e d i n g . The d r i e d p a r t i c u l a t e f u e l i s then burned i n suspension along the c o n c e n t r i c v e r t i c a l c y l i n d e r ; 3.4 By-products of the K r a f t Process As mentioned i n the i n t r o d u c t i o n , the major by-products i n k r a f t p u l p i n g are t u r p e n t i n e , t a l l o i l , k r a f t l i g n i n (as produced by westvaco, see below), some s u l f u r c o n t a i n i n g v o l a t i l e compounds, l i k e dimethyl s u l f o x i d e and s o l u b l e wood r e s i d u e f u e l s . To j u s t i f y expanded e f f o r t s i n by-products recovery, c e r t a i n c r i t e r i a must be met. The economic c o n s i d e r a t i o n s demand that by-product values exceed value as f u e l , as w e l l as the cost of chemicals t h a t have to be s a c r i f i e d or a l t e r e d i n order to o b t a i n the by-product and, of course, c a p i t a l c o s t s need to be met. T h i s review w i l l examine some aspects of k r a f t t a l l o i l and k r a f t l i g n i n recovery. 3.4. 1 T a l l O i l In a c o n v e n t i o n a l k r a f t p u l p i n g o p e r a t i o n , s u l f a t e soap i s u s u a l l y recovered i n : 1) The washer foam tower; 2) The weak l i q u o r s t o r a g e tanks; 3) An i n t e r m e d i a t e p o i n t i n the m u l t i p l e -e f f e c t e v a p o r a t o r s at l i g u o r s o l i d content of 25-28%; 4) The 41 heavy black l i q u o r o x i d a t i o n foam tower; and/or 5) The heavy l i q u o r s torage tanks. Recovery u s u a l l y i n v o l v e s using a skimmer to remove the foam t h a t f l o a t s on top of the l i g u o r ; Withdrawing foam through manifold v a l v e s i s a l s o p r a c t i c e d (35) . Some f a c t o r s a f f e c t the t a l l o i l y i e l d ; Wood f u r n i s h t o the pu l p i n g process c r i t i c a l l y a f f e c t s t a l l o i l recovery, as d i f f e r e n t woods have d i f f e r e n t e x t r a c t i v e contents and compositions. There are a l s o s e a s o n a l v a r i a t i o n s , with higher y i e l d s i n winter and e a r l y s p r i n g than other seasons (83,138). T h i s i s d i r e c t l y r e l a t e d t o the physiology of the t r e e ; Long term storage of ch i p s causes lowering of e x t r a c t i v e contents and consegu'ently lower t a l l o i l y i e l d . The most s e r i o u s l o s s e s occur f o r conjugated r e s i n a c i d s , i ; e . , the a b i e t a d i e n o i c a c i d s . The nature of the l o s s e s i s not w e l l understood, s i n c e o x i d i z e d r e s i n a c i d contents do not show a corresponding i n c r e a s e , nor can microorganism account f o r the degradation. One p l a u s i b l e e x p l a n a t i o n could be p o l y m e r i z a t i o n of r e s i n a c i d s i n t o i n s o l u b l e forms (160). Losses i n t a l l o i l y i e l d s up to 70-80% over e i g h t weeks c h i p storage have been noted (138). Methods of p u l p i n g and p u l p i n g a d d i t i v e s a l s o i n f l u e n c e t a l l o i l y i e l d s . R e s i d u a l a c t i v e a l k a l i c o n c e n t r a t i o n i n black l i q u o r has an e f f e c t ; Higher a c t i v e a l k a l i i n d i c a t e s more complete s a p o n i f i c a t i o n o f t a l l o i l p r e c u r s o r s and the a l k a l i a l s o e x e r t s a s a l t i n g out e f f e c t which helps separate t a l l o i l soap (138) . P e a r l and Dickey (121) s t u d i e d the e f f e c t of o x y g e n - a l k a l i p u l p i n g on t a l l o i l y i e l d and components and found that y i e l d decreased s u b s t a n t i a l l y i n soda-oxygen p u l p i n g . However, the t a l l o i l components were r e l a t i v e l y s t a b l e under 42 the p u l p i n g c o n d i t i o n s used. The lower y i e l d was due to t a l l o i l r e t e n t i o n i n the pulps. They a l s o n o t i c e d that a b i e t i c a c i d was almost e n t i r e l y converted to d e h y d r o a b i e t i c a c i d . Another study (39) d e a l i n g with o x y g e n - a l k a l i pulped thermomechanical f i b e r supported t h e i r f i n d i n g s . Adjustments by a d d i t i o n of anthraguinone to a l k a l i n e p u l p i n g l i g u o r was a l s o examined (65) . Anthraguinone had no e f f e c t on conjugated f a t t y a c i d s , but i t tended t o o x i d i z e a b i e t i c a c i d to d e h y d r o a b i e t i c a c i d . O v e r a l l i n f l u e n c e of anthraguinone on t a l l o i l components was minimal. The e f f e c t of mixing black l i g u o r from p u l p i n g hardwood f u r n i s h e s has been examined (138). Soap s e p a r a t i o n seemed to be i n h i b i t e d due to d i s s o l u t i o n of softwood soap i n the hardwood l i g u o r t o the s a t u r a t i o n p o i n t . Higher calcium content of hardwood l i g u o r a l s o i n h i b i t s soap s e p a r a t i o n . Another study (95) based on l a b o r a t o r y cooks, however, found t h a t up to 30% of oak-gum hardwood d i s s o l v e d s o l i d s had no e f f e c t on soap s o l u b i l i t y i n a mixed pine-hardwood black l i g u o r . P e a r l (120) noted that the high p r o p o r t i o n s of l o n g - c h a i n f a t t y a c i d s i n southern pine bark e x t r a c t i v e s rendered the a l k a l i n e s o l u t i o n of pine bark s u i t a b l e f o r i n c r e a s i n g the content of black l i g u o r f a t t y a c i d s so as to improve the s e p a r a t i o n of soap. The scheme i s e s p e c i a l l y v a l u a b l e i n d e a l i n g with i n c r e a s e d y i e l d from r e s i n - s o a k e d "light-wood". 3.4.2 K r a f t L i g n i n A t y p i c a l pine black l i g u o r s o l i d c o n s i s t s of about 20% i n o r g a n i c components, 28% hydroxy a c i d s and l a c t o n e s as carbohydrate degradation products, and about 40% a l k a l i l i g n i n . 43 D i s s o l v e d l i g n i n i s the l a r g e s t f r a c t i o n i n black l i g u o r s o l i d s . At p r esent, most of the or g a n i c components i n black l i g u o r are simply burned to generate energy f o r the process. In many ways k r a f t l i g n i n i s a more v e r s a t i l e raw m a t e r i a l than l i g n i n s u l f o n a t e s from spent s u l f i t e l i g u o r s . I t can be e a s i l y i s o l a t e d from the spent p u l p i n g l i g u o r , i s s o l u b l e i n many o r g a n i c s o l v e n t s , possesses t h e r m o p l a s t i c p r o p e r t i e s , c o n t a i n s l e s s s u l f u r , and i s s o l u b l e i n c a u s t i c s o l u t i o n s . K r a f t l i g n i n i s a polymeric m a t e r i a l c o n s i s t i n g roughly of 65% carbon, 5% hydrogen and 30% oxygen. I t i s g u i t e r e a c t i v e and can be e t h e r i f i e d , e s t e r i f i e d , n i t r a t e d , mercurated and halogenated; I t can r e a c t a l s o with phenols, amines, aldehydes and s u l f i d e s o (68) . Recently Lange and Schweers (84) s t u d i e d carboxymethylation of organosolv and k r a f t l i g n i n s . About 60 to 70% of the hyd r o x y l groups i n the l i g n i n s were r e a c t e d with bromoacetic a c i d . T h i s and other s t u d i e s (24,69) explored the use of k r a f t l i g n i n as sources of polyurethane and other polymers. K r a f t l i g n i n can be i s o l a t e d by simply a c i d i f y i n g the black l i g u o r . Reduction of l i g u o r pH reduces l i g n i n s o l u t i b i l i t y and v a r i o u s l i g n i n f r a c t i o n s p r e c i p i t a t e out. Most other d i s s o l v e d o r g a n i c components are l e s s a f f e c t e d by pH change and remain i n s o l u t i o n . About 80 to 90% of k r a f t l i g n i n can be p r e c i p i t a t e d by lowering l i q u o r pH t o below 3. Lowering of pH i s a l s o accompanied by e v o l u t i o n of hydrogen s u l f i d e and carbon d i o x i d e gases, c a u s i n g a f r o t h i n g problem. To overcome t h i s problem, a c i d i f i c a t i o n i s u s u a l l y c a r r i e d out i n two stages, f i r s t using carbon d i o x i d e from f l u e gas or s u l f u r i c a c i d to reach a pH of 44 about 9. T h i s p r e c i p i t a t e s most of the l i g n i n as sodium s a l t s (103). F i l t r a t i o n of t h i s sodium l i g n a t e , however, i s q u i t e d i f f i c u l t due to i t s c o l l o i d a l p a r t i c l e s i z e ; Heating of l i q u o r to a temperature above 800C coa g u l a t e s the l i g n i n p a r t i c l e s and eases f i l t r a t i o n . A d d i t i o n of c e r t a i n water-immicible o r g a n i c s o l v e n t s a l s o helps (155). A f t e r the l i g n i n has been separated as sodium s a l t at t h i s stage, i t i s suspended i n water and a c i d i f i e d with mineral a c i d to a pH of 3 or lower a t 80° to 90°C. The choice of a c i d i f i c a t i o n agents i s l i m i t e d by c o m p a t i b i l i t y with i n o r g a n i c chemical recovery; Only carbon d i o x i d e and s u l f u r i c a c i d are used, so as not t o i n t r o d u c e new anions i n t o the l i q u o r stream. Numerous s t u d i e s and patents r e f e r to k r a f t l i g n i n i s o l a -t i o n . The m a j o r i t y of these are v a r i a t i o n s on the b a s i c carbon d i o x i d e or s u l f u r i c a c i d schemes, as f i r s t proposed by Tomlinson and Tomlinson (150). Various designs of a c i d i f i c a t i o n d evices and carbon d i o x i d e pressures have been proposed to achieve optimal s e p a r a t i o n of k r a f t l i g n i n from black l i q u o r (1,103). The e l e c t r o l y t i c method mentioned e a r l i e r f o r sodium recovery (50,76) a l s o recovers a l i g n i n p r e c i p i t a t e a t the anode. A more r e c e n t study on carbon d i o x i d e p r e c i p i t a t i o n of k r a f t l i g n i n was c a r r i e d out by Alen et a l . ( 1 ). Various c a r b o n a t i o n pressures were used and the r e s u l t s i n d i c a t e that at higher pressure the carbonation time can be s u b s t a n t i a l l y shortened; L i q u o r c o n c e n t r a t i o n a l s o i n f l u e n c e s y i e l d . Maximum y i e l d was obtained a t s o l i d content of 27%. Washing of the p r e c i p i t a t e d l i g n i n d i d not remove about 3% of the t o t a l black 45 l i g u o r sodium content, which was bound to l i g n i n ; About a quarter of the l i g n i n r e d i s s o l v e d i n water during washing, i n d i c a t i n g that the s a l t i n g out e f f e c t i s r a t h e r prominent i n the o r i g i n a l l i g u o r . K r a f t l i g n i n has p o t e n t i a l and p r a c t i c a l uses as a d d i t i v e s i n rubber products, c o n s t r u c t i o n boards, paperboard and as polymer product raw m a t e r i a l s . Westvaco i s the only North American company producing k r a f t l i g n i n products through the a c i d i f i c a t i o n process; The t o t a l output i n 1977 was 60 m i l l i o n pounds of v a r i o u s grades of a l k a l i \ l i g n i n ; Most of the l i g n i n was s u l f o n a t e d to produce l i g n o s u l f o n a t e s . Because of g r e a t e r p u r i t y and the c o n t r o l l e d degree of s u l f o n a t i o n , i t i s very c o m p e t i t i v e to l i g n o s u l f o n a t e s from s u l f i t e m i l l s (18). In recent years, because of s k y - r o c k e t i n g p e t r o c h e m i c a l p r i c e s , a t t e n t i o n has been d i r e c t e d toward use of k r a f t black l i g u o r or l i g n i n obtained from the black l i q u o r as s u b s t i t u t e s f o r p h e n o l i c r e s i n s ; Dolenko and C l a r k e (31) formulated a waterproof r e s i n based on k r a f t l i g n i n . A one-stage phenol formaldehyde (PF) r e s i n was prepared; the p r e p a r a t i o n i n v o l v e d m e t h y l o l a t i o n of the k r a f t l i g n i n black l i g u o r c o n c e n t r a t e , pH adjustment and then b l e n d i n g with an a c i d c u r i n g PF r e s i n . T h i s r e s i n showed c o n s i d e r a b l e promise as a waterproof adhesive f o r plywood and waferboard; Up to 70% of the petroleum based PF r e s i n s c o u l d be r e p l a c e d with k r a f t l i g n i n on a weight-to-weight b a s i s without i l l e f f e c t . Gupta and Sehgal (53) s t u d i e d the e f f e c t of b l e n d i n g v a r i o u s p r o p o r t i o n s of t h i o l i g n i n i s o l a t e d from k r a f t black 46 l i g u o r t o r e p l a c e phenol components of a PF r e s i n . They found a p o s i t i v e c o r r e l a t i o n between plywood bond s t r e n g t h , v i s c o s i t y and molecular weights c f the r e s i n t o a c e r t a i n p o i n t . T h i o l i g n i n from p u l p i n g low s p e c i f i c g r a v i t y woods had higher glue f a i l u r e s than t h a t from high s p e c i f i c g r a v i t y woods. E n k v i s t (38). a l s o patented the use of 25% s o l i d s black l i g u o r blended with formaldehyde and phenol or c r e o s o l r e s i n s as binder f o r plywood and p a r t i c l e b o a r d . The phenol and c r e o s o l r e s i n content ranged from 15 to 50%. Demands f o r chemical u t i l i z a t i o n s of v a r i o u s l i g n i n and p h e n o l i c components from p u l p i n g l i q u o r s are l i k e l y t o i n c r e a s e i n the near f u t u r e . Black l i g u o r e x t r a c t i o n c o u l d provide a d d i t i o n a l sources of such m a t e r i a l s to meet the demands. 47 I I I MATERIALS AND METHODS Lodgepole pine (Pinus c o n t o r t a var. l a t i f o l i a Engelm.) was chosen f o r study, mainly because i t forms e x t e n s i v e stands i n c e n t r a l B r i t i s h Columbia and i s an important lumber and pulpwood s p e c i e s . Samples of lodgepole pine bark and t e c h n i c a l f o l i a g e ( f o l i a g e with twigs 6mm or l e s s i n diameter) together with k r a f t process weak black l i g u o r were c o l l e c t e d A p r i l 19, 1978 at Weyerhaeuser Canada, L t d . , Kamloops, B.C. A l l m a t e r i a l s came from two t r e e s f e l l e d s p e c i f i c a l l y f o r t h i s study. Black l i g u o r and'tree samples were s t o r e d and t r a n s p o r t e d under n i t r o g e n . A f t e r a r r i v i n g at the u n i v e r s i t y , they were t r a n s f e r r e d to a c o l d room and kept at about 2°C. 1 Petroleum Ether E x t r a c t i o n of Lodgepole Pine Samples In order to o b t a i n i n f o r m a t i o n as to the v a r i a b i l i t y of p o t e n t i a l t a l l o i l y i e l d s from the v a r i o u s samples, d i r e c t petroleum ether e x t r a c t i o n of meals from lodgepole pine t r e e p a r t samples were c a r r i e d out i n Soxhlet e x t r a c t o r s . M a t e r i a l s f o r t h i s p a r t of the study i n c l u d e d bark from the two t r e e s designated (E)ast and (W)est t r e e s a c c o r d i n g to t h e i r l o c a t i o n i n the stand and t e c h n i c a l f o l i a g e s from three d i f f e r e n t p o s i t i o n s of each t r e e crown. These were designated (T)op, (M)iddle and (B) ottom p o s i t i o n s . Pine cones made up s u b s t a n t i a l f r a c t i o n s of the t o t a l weights i n the top and middle p o s i t i o n s of the f o l i a g e samples. These were removed and analyzed s e p a r a t e l y . F i v e - c e n t i m e t e r s e c t i o n s of the t r e e stems 48 were a l s o cut at the b ( R ) e a s t - h e i g h t s and the bases of t r e e (C)rowns. Heartwood and sapwood samples were ob t a i n e d from these s e c t i o n s . Four d i f f e r e n t d r y i n g treatments were used to examine e f f e c t s of v a r i o u s d r y i n g methods on recovery of petroleum e t h e r e x t r a c t i v e s . Samples were cut i n t o segments and randomly separated i n t o f o u r groups f o r the d r y i n g treatments. Freeze-d r y i n g , a i r - d r y i n g * as w e l l as 70° and 105°C oven^drying were used. For f r e e z e - d r y i n g , l i g u i d n i t r o g e n was used to quench samples suddenly (-1960C), then the f r o z e n samples were put i n the vacuum chamber of a V i r t i s U n i - t r a p Model 10-100 f r e e z e -d r y e r . Pressure i n the chamber was kept below 0.2 t o r r and d r y i n g l a s t e d f o r about 48-hr. For a i r - d r y i n g , samples were spread out on bench tops i n a w e l l v e n t i l a t e d room f o r 4 to 6-days (bark d r i e d f a s t e r than the f o l i a g e samples). Oven-dr y i n g s were c a r r i e d out by p u t t i n g samples i n T e f l o n screen backed wood frames, f o l l o w e d by heating i n an oven at the p r e s c r i b e d temperature. Sample weights were checked every 2-hr u n t i l weights were constant. Because of hardness, pine cones were f i r s t crushed with a h y d r a u l i c press at 2000 p s i and c o a r s e l y separated i n t o fragments, before d r y i n g treatments were c a r r i e d out. A f t e r the samples were d r i e d to a moisture content of 10% or l e s s , they were ground i n a Wiley m i l l t o pass 2-mm screen. Approximately 5 to 8-g of the sample m a t e r i a l were put i n 32 x 80-mm t a r e d paper thimbles. Six Soxhlet e x t r a c t o r s were run as a batch. Each sample was r e p l i c a t e d t h r e e times* Petroleum ether of b.p. 30°-60°C was used as the s o l v e n t and e x t r a c t i o n 49 l a s t e d 8-hr with approximately s i x c y c l e s per hour; C o n c u r r e n t l y , two tared sample r e p l i c a t e s were oven-dried f o r 24-hr to determine moisture c o n t e n t s . In cases when the two moisture content r e s u l t s were more than 0.2% a p a r t , a d d i t i o n a l moisture measurements were c a r r i e d out to e s t a b l i s h a mean with high p r e c i s i o n . At the end of e x t r a c t i o n excess s o l v e n t i n the e x t r a c t o r s was decanted and the thimbles were d r i e d i n the oven f o r 48-hr t o g i v e e x t r a c t e d , oven-dried sample weights. The f l a s k s c o n t a i n i n g e x t r a c t s were f l a s h evaporated to remove the s o l v e n t then oven-dried a t 105°C f o r 30-min. Both f l a s k weight gains and thimble weight l o s s e s gave petroleum ether e x t r a c t s when d i v i d e d by oven-dry weight of the unextracted sample; E x t r a c t i o n r e s u l t s are summarized i n Table 1 and d e t a i l e d data are presented i n Appendix 2. V a r i a t i o n s a t t r i b u t a b l e t o between t r e e s , crown p o s i t i o n s and d r y i n g e f f e c t s were examined by a n a l y s i s of v a r i a n c e based on f l a s k evaporated y i e l d data. These r e s u l t s are presented i n the Tables 2 to 6. 2 Black Liguor E x t r a c t i o n Other batches of bark and f o l i a g e samples from each of the two t r e e s were combined; A f t e r a i r - d r y i n g f o r 4 to 6-days, these were ground i n a Wiley m i l l to three mesh s i z e s as coarse, medium, and f i n e f r a c t i o n s (passing 6, 4, and 2-mm screens, r e s p e c t i v e l y ) . The meals were put i n g a l l o n s i z e g l a s s j a r s with a i r t i g h t l i d s . A f t e r f l u s h i n g with n i t r o g e n , the j a r s were st o r e d i n the c o l d room. Sieve a n a l y s i s of the m a t e r i a l s are presented i n Table 7. 50 The b l a c k l i g u o r contained 15% s o l i d s (147) and had a pH of 13.0. O r i g i n a l t a l l o i l content of the l i g u o r was 0.8% on l i g u o r s o l i d b a s i s a c c o r d i n g t o the method t o be de s c r i b e d * In cooking experiments, l o d g e p o l e pine bark or t e c h n i c a l f o l i a g e meals (30-g moisture f r e e basis) were put i n 350-ml screw-top s t a i n l e s s s t e e l bombs with 200-ml of black l i g u o r . Two l i q u o r s were used, the o r i g i n a l as c o l l e c t e d (N l i g u o r ) and t h i s r e i n f o r c e d with 5 g/1 c f sodium hydroxide (R l i g u o r ) . A f t e r soaking o v e r n i g h t the bombs were heated i n the F o r i n t e k Lab d i g e s t e r system using a standard k r a f t cook cam temperature c o n t r o l schedule (rate of r i s e at 66oc/hr). There were 22 bombs i n a batch, 16 i n the main d i g e s t e r and s i x i n s a t e l l i t e d i g e s t e r s . The independent s a t e l l i t e d i g e s t e r s were used f o r time s e r i e s w i t h i n cooks. Because of the long cooking hours r e q u i r e d f o r the 80°C cooking which d i d not f i t the d a i l y schedule of F o r i n t e k Corp, these bombs were t r a n s f e r e d to the F a c u l t y of F o r e s t r y and cooking was c a r r i e d out i n a t e m p e r a t u r e - c o n t r o l l e d 0.2x0.2x2-m s t a i n l e s s s t e e l trough. C o n t r o l l e d h e a t i n g was provided by a Haake FK 2 water bath and an a u x i l i a r y heater. In a d d i t i o n , a compressed-air d r i v e n s t i r r e r was used t o a i d water c i r c u l a t i o n . Temperature of the bath water was monitored with thermometers and recorded on c h a r t paper from a thermocouple s i g n a l ; At the c o n c l u s i o n of cooking the d i g e s t e r was co o l e d r a p i d l y by c o l d water f l u s h i n g . Bomb contents were t r a n s f e r r e d with a s p a t u l a as thoroughly as p o s s i b l e i n t o 500-ml p l a s t i c c o n t a i n e r s , s e a l e d and s t o r e d a t 2°C. Cooks at f i v e temperature-time schedules were done. These c o n d i t i o n s were: 80° f o r 12-hr maximum time, 100° f o r 4-hr, 120° 51 f o r 2-hr, 145° f o r 1.5-hr, and 170° f o r 1-hr. The times c i t e d were at temperature maxima. The d e t a i l e d cooking schemes are presented i n Table 8 and the temperature-time p r o f i l e s appear as F i g 1. As comparisons, some lodgepole pine sapwood and heartwood meals were a l s o cooked with black l i g u o r ; Some problems were encountered when t r y i n g to completely separate black l i g u o r from the remaining s o l i d r e s i d u e s . F i l t r a t i o n and decanting were t r i e d without success; The l a r g e sample volume a l s o precluded l a b o r a t o r y c e n t r i f u g i n g ; A f i l t e r press adapted from a k i t c h e n r i c e r f i t t e d with 150-mesh s t a i n l e s s s t e e l screen was found to perform s a t i s f a c t o r i l y . E v e n t u a l l y , a f i l t e r press with long handles f o r b e t t e r l e v e r a g e , removable upper l e v e r , p i s t o n f i t t e d with rubber o - r i n g and s t a i n l e s s s t e e l c y l i n d e r with p e r f o r a t e d bottom p l a t e and 150-mesh screen f i t t i n g was fashioned (see F i g 2) . I n i t i a l BLE l i g u o r f r a c t i o n s were separated from r e s i d u a l s o l i d s by the f i l t e r p ress; Liguor recovery depended on the m a t e r i a l , p a r t i c l e s i z e and cooking c o n d i t i o n s . As pressure was a p p l i e d , the l i g u o r d i s t r i b u t i o n became s t r a t i f i e d ; The bottom l a y e r of the l i g u o r - r e s i d u e mass adjacent to the s c r e e n became w e l l drained* while the middle p o r t i o n was s t i l l r i c h i n l i g u o r . E i t h e r the masses had to be turned with a s p a t u l a , or a d d i t i o n a l time was needed to l e t the l i g u o r d i f f u s e to the bottom before e f f e c t i v e p r e s s i n g c o u l d be resumed. S e v e r a l c y c l e s of p r e s s i n g with i n t e r m i t t e n t w a i t i n g p e r i o d s were needed; F i r s t l i g u o r f r a c t i o n y i e l d s were i n the order of 130 to 190-ml, compared to the 200-ml i n i t i a l a d d i t i o n . Second l i g u o r f r a c t i o n s were 52 c o l l e c t e d by s t e e p i n g and squeezing the r e s i d u e s i n three c y c l e s of 200-ml warm water. Subsequently, these f r a c t i o n s were f l a s h evaporated to reduce the volume from around 600-ml t o about 250-ml. Three r e p l i c a t i o n s each o f i n i t i a l and secondary l i q u o r f r a c t i o n s were analyzed. T a l l o i l contents i n the e x t r a c t i o n l i q u o r s were estimated a c c o r d i n q to the method of Saltsman and Kuiken (132), as adapted to a s m a l l e r l i q u o r volume. The method was s c a l e d down 5:1. There were c e r t a i n other m o d i f i c a t i o n s of the method, such as using aluminum weighing d i s h e s i n p l a c e of eva p o r a t i o n dishes and use of lead-weighted beakers i n a hot-water bath i n s t e a d of f l o a t i n g e v a p o r a t i o n dishes on top of the water bath. Thick l a y e r s o f scum sometimes appeared at the petroleum ether-water i n t e r f a c e , e s p e c i a l l y when f o l i a g e e x t r a c t s were analyzed. Reducing the sample volume by h a l f and u s i n g e x t r a acetone to d i s p e r s e the scum seemed t o l e s s e n the problem. R e p r o d u c i b i l i t y of the r e s u l t s was not adver s e l y a f f e c t e d by the scum problem; Another t a l l o i l y i e l d method, using t r i c h l o r o e t h y l e n e as t a l l o i l soap s o l v e n t (156) was t r i e d . The r e p r o d u c i b i l i t y of r e s u l t s was i n f e r i o r to the modified Saltsman and Kuiken method. Phase s e p a r a t i o n of the s o l v e n t s took longer, and even then some agueous o c c l u s i o n s i n the l i p o p h i l e s o l v e n t phase were obvious. The s o l i d r e s i d u e s a f t e r f i l t e r p r e s s i n g secondary l i g u o r f r a c t i o n s were c o l l e c t e d over a 200-mesh s e i v e and oven-dried at 1050C f o r 48-hr. 3 E l e c t r o c h e m i c a l Technigues and Black L i g u o r E x t r a c t i o n The black l i g u o r a c t i v e a l k a l i and sodium s u l f i d e 53 d e t e r m i n a t i o n s as o u t l i n e d i n TAPPI Standard T625 ts-64 (147) were c a r r i e d out. The r e s u l t s of these p o t e n t i o m e t r i c t i t r a t i o n s are presented i n F i g 12 and 13. For d i r e c t p o t e n t i o m e t r i c monitoring of the BLE r e a c t i o n s , v a r i o u s instruments were needed. For want of m u l t i p l e - c h a n n e l eguipment, the pH and sodium io n measurements were done with two d i f f e r e n t potentiometers. S u l f i d e i o n c o n c e n t r a t i o n s should be monitored, a l s o , but t h i s was omitted due to eguipment c o n s t r a i n t s . One meter was a F i s c h e r Accumet pH meter Model 750 with temperature probe and LED d i g i t a l d i s p l a y , and the other was a Radiometer pH meter Model 26. The e l e c t r o d e s used i n the study i n c l u d e d a F i s h e r No. 13-639-20 sodium ion s e l e c t i v e e l e c t r o d e , p a i r e d with an Orion double j u n c t i o n r e f e r e n c e e l e c t r o d e . Model 90-02-00. F i l l i n g s o l u t i o n s f o r the r e f e r e n c e e l e c t r o d e s were 10% potassium n i t r a t e s o l u t i o n f o r the outer chamber, and Orion 90-00-02 s o l u t i o n c o n t a i n i n g s i l v e r c h l o r i d e f o r the i n n e r chamber: The pH e l e c t r o d e used was a Corning Model 476024. A Radiometer s i l v e r b i l l e t e l e c t r o d e , Type P4011 coated with s i l v e r s u l f i d e was used i n the sodium s u l f i d e d e t e r m i n a t i o n . The meter outputs were recorded with a Hewlett-Packard Moseley 7100B two-channel s t r i p c h a r t r e c o r d e r . T h i s setup allowed e f f e c t i v e monitoring of hydroxide and sodium i o n a c t i v i t i e s c o n t i n u o u s l y i n a d i r e c t p o t e n t i o m e t r i c manner. Before any a c t u a l measurement co u l d be c a r r i e d out, c e r t a i n p r e l i m i n a r y procedures had t o be completed, such as c a l i b r a t i o n of e l e c t r o d e s with standard s o l u t i o n s , establishment of e l e c t r o d e temperature c o e f f i c i e n t s , and c o r r e c t i o n s f o r 54 l i q u i d - j u n c t i o n p o t e n t i a l s and sodium e r r o r s i n the pH e l e c t r o d e s . A double j u n c t i o n r e f e r e n c e e l e c t r o d e was used to avoid contamination of the l i q u i d - j u n c t i o n with black l i q u o r s u l f u r components. P o t e n t i a l of t h i s r e f e r e n c e e l e c t r o d e was checked p e r i o d i c a l l y to ensure proper f u n c t i o n i n g . The pH e l e c t r o d e p o t e n t i a l s were measured by s e r i a l d i l u t i o n of standard sodium hydroxide s o l u t i o n s * One normal sodium hydroxide stock s o l u t i o n was prepared from degassed d i s t i l l e d water and Anachemia A c c u l u t e ampules. For sodium e r r o r d e t e r m i n a t i o n s , the method of Swartz (145) was f o l l o w e d . The pH meter readings of a 0.1 Molal sodium hydroxide s o l u t i o n and a s o l u t i o n c o n t a i n i n g 0.1 M o l a l sodium hydroxide and l a r g e excess (1.0 Molal) of sodium c h l o r i d e were compared. The d i f f e r e n c e i n p o t e n t i a l was c o r r e c t e d f o r l i q u i d j u n c t i o n p o t e n t i a l and c o r r e l a t e d with hydrogen and sodium i o n a c t i v i t i e s i n the two s o l u t i o n s to o b t a i n s e l e c t i v i t y c o e f f i c i e n t and subseguent e s t i m a t i o n of sodium e r r o r . Thermal c o e f f c i e n t s f o r the pH and sodium-ion s e l e c t i v e e l e c t r o d e s were e s t a b l i s h e d by measureing the p o t e n t i a l of each e l e c t r o d e i n b lack l i q u o r at 25° and 7 0 O C . D i f f e r e n c e s i n observed p o t e n t i a l s were used to e s t a b l i s h the temperature c o e f f i c i e n t s . In the d i r e c t p o t e n t i o m e t r i c experiment, a 500-ml p l a s t i c c o n t a i n e r f i t t e d with t i g h t P l e x i g l a s s l i d and having p o r t s f o r e l e c t r o d e s was f a b r i c a t e d * E l e c t r o d e s were i n s e r t e d through the p o r t s to a p p r o p r i a t e depth. Each port was f i t t e d with an o - r i n g to keep the r e a c t i o n v e s s e l a i r - t i g h t * P o r t i o n s of 300-ml black l i g u o r (N l i q u o r ) and 45-g (0-D basis) of the f i n e f r a c t i o n bark 55 or t e c h n i c a l f o l i a g e samples were used i n the study. A basket made of 150-mesh s t a i n l e s s s t e e l screen was placed i n the v e s s e l t o h o l d the sample and prevent the s o l i d m a t e r i a l from s e t t l i n g and i n t e r f e r r i n g with the s t i r r i n g a c t i o n of a magnetic s t i r r i n g bar. A Haake Model FK 2 f o r c e d - c i r c u l a t i o n water bath with e x t e r n a l c i r c u l a t i o n t o accommodate a magnetic s t i r r e r was used to c o n t r o l the r e a c t i o n temperature. The whole setup i s d e p i c t e d i n F i g 3. The bath and the black l i g u o r were preheated t o 70°C be f o r e the sample was i n t r o d u c e d to the l i g u c r - c o n t a i n i n g v e s s e l . Changes i n the pH and sodium i o n a c t i v i t i e s were monitored c o n t i n u o u s l y f o r 20-hr. The data thus obtained were c a l i b r a t e d with the standard e s t a b l i s h e d e a r l i e r i n the p r e l i m i n a r y procedures. 56 IV RESULTS AND DISCUSSION 1 Petroleum Ether E x t r a c t i o n of Lodgepole Pine Tree Parts T h i s study was c a r r i e d out to e s t a b i l i s h p o t e n t i a l amounts of e x t r a c t a b l e l i p i d s i n v a r i o u s lodgepole pine t r e e p a r t s . F u r t h e r , the e f f e c t of d i f f e r e n t d r y i n g methods on e x t r a c t i v e y i e l d was examined. 1.1 Choice of Solvent L i p o p h i l e e x t r a c t i v e s i n d i c a t e p o t e n t i a l t a l l o i l y i e l d by the k r a f t p rocess, or i n the case of a c i d i c p u l p i n g processes, the extent of p i t c h problem (113). The choice of s o l v e n t f o r wood e x t r a c t i o n o f t e n depends on the purpose of the a n a l y s i s . The ethanol-benzene mixture was g e n e r a l l y used to o b t a i n the " t o t a l " e x t r a c t i v e content i n wood. To assess the sample l i p i d content, however, a l e s s p o l a r s o l v e n t i s needed. D i e t h y l ether t r a d i t i o n a l l y f u l f i l l s such a purpose, but some p h e n o l i c f r a c t i o n s are e x t r a c t e d by the s o l v e n t . The a n e s t h e t i c and e x p l o s i v e c h r a c t e r i s t i c s of d i e t h y l ether r e g u i r e s p e c i a l p r e c a u t i o n i n h a n d l i n g . As an a l t e r n a t e TAPPI standard T5-OS-73 recommands the use of dichloromethane f o r l i p i d e x t r a c t i o n . Since the s o l v e n t i s t o x i c , work needs to be done under a fumehood; Petroleum ether has a l s o been used f o r wood, bark and t e c h n i c a l f o l i a g e l i p i d e x t r a c t i o n i n s e v e r a l s t u d i e s (54,67,113), and was shown to be g u i t e s a t i s f a c t o r y . Despite i t s 57 f l a m m a b i l i t y , i t handles q u i t e w e l l . In t h i s study i t pro v i d e d a c o n s i s t e n t l i n k between the d i r e c t l i p i d e x t r a c t i o n d e s c r i b e d here and the BLE r e s u l t s d i s c u s s e d elsewhere. T h i s occurs because the same s o l v e n t i s used i n the Saltsman and Kuiken procedure f o r determining t a l l o i l ( 1 3 2 ) . 1 . 2 General D i s c u s s i o n on the Drying E f f e c t Z i n k e l (159) repo r t e d an e l a b o r a t e procedure f o r ha n d l i n g wood i n t a l l o i l p r e c u r s o r s t u d i e s . Fresh cut l o b l o l l y pine s e c t i o n s were frozen with dry i c e to stop metabolic a c t i v i t y and provide an i n e r t atmosphere. Sample d i v i s i o n s were c a r r i e d out with n i t r o g e n f l u s h i n g to prevent o x i d a t i o n . These p r e c a u t i o n s were necessary t o preserve the d e l i c a t e sample composition. The c u r r e n t study r e p o r t s only r e l a t i v e p o t e n t i a l crude t a l l o i l y i e l d s and no c o m p o s i t i o n a l study was intended* Hence, f r e s h l o dgepole pine t r e e p a r t s were d i r e c t l y s u b j e c t e d to dr y i n g treatment before d i v i s i o n and e x t r a c t i o n . Thereby, besides s t o r i n g d i v i d e d samples under n i t r o g e n and at c o l d temperature, no other measures were taken to ensure l i p i d s t a b i l i t y . From e x t r a c t i o n r e s u l t s , s p e c i a l f r e e z e - d r y i n g c l e a r l y preserved the e x t r a c t a b l e l i p i d s most e f f e c t i v e l y , but a i r - d r y i n g f o r short p e r i o d s a l s o gave n o n - d i s t i n g u i s h a b l e r e s u l t s i n bark samples as r e i n f o r c e d by Duncan's t e s t . For other samples the d i f f e r e n c e s between these two methods were s i g n i f i c a n t but g e n e r a l l y minor. Oven-drying tended to d r a s t i c a l l y lower e x t r a c t i v e y i e l d s * P o s s i b l e reasons f o r y i e l d l o s s e s c o u l d be p a r t i a l l o s s of r e s i n a c i d s , formation of d e h y d r o a b i e t i c a c i d and p o l y m e r i z a t i o n of some of the l i p i d s 58 (160). A r t i f a c t s c o n t a i n i n g hydroxy groups have been found a f t e r prolonged storage (113). Nelson et a l . (113) s t u d i e d d r y i n g e f f e c t s on Monterey pine (Pinus r a d i a t a D. Don) petroleum ether e x t r a c t s . They found t h a t f r e e z e - d r y i n g and shor t p e r i o d a i r - d r y i n g gave the best r e s u l t s , while long p e r i o d s of a i r - d r y i n g and oven-drying s u b s t a n t i a l l y reduced the amount of e x t r a c t i v e s , t h e i r r e s u l t s are supported by the present study, which i n c l u d e s an even more advanced f r e e z e d r y i n g technigue than used p r e v i o u s l y . D i f f e r e n c e s i n l i p i d composition of v a r i o u s t r e e p a r t s could a l s o i n f l u e n c e e x t r a c t i o n r e s u l t s when s u b j e c t e d to d i f f e r e n t d r y i n g treatments. T e c h n i c a l f o l i a g e tended to l o s e a l a r g e r p r o p o r t i o n of e x t r a c t s with oven-drying than the bark, samples (Table 2). The v o l a t i l e terpene contents of both m a t e r i a l s seem too minute to account f o r the d r a s t i c change i n t e c h n i c a l f o l i a g e e x t r a c t i o n r e s u l t s . As pointed out by Hannus (54), r ecovery of t e c h n i c a l f o l i a g e e x t r a c t s depends on the p r o p o r t i o n of branches and needles. D e s p i t e e f f o r t s t o randomize samples, the i n t r i n s i c heterogeneous nature of t e c h n i c a l f o l i a g e may cause s y s t e m a t i c e r r o r s among the samples. Lack of d e t a i l e d f o l i a g e l i p i d composition precluded e x p l a n a t i o n s based on d i f f e r e n c e s i n l i p i d composition; Perhaps t e c h n i c a l f o l i a g e c o n tained g r e a t e r p r o p o r t i o n s of r e s i n a c i d s and tended t o l o s e t h i s more r e a d i l y than a f a t t y a c i d f r a c t i o n . Even the b e t t e r r e s u l t s achieved by f r e e z e - d r y i n g may not re p r e s e n t the t o t a l l i p i d content i n f r e s h samples. As example, the f r e e z e - d r i e r c o l d trap thawed a f t e r t r e a t i n g t e c h n i c a l f o l i a g e samples contained a s m a l l l a y e r of greenish o i l . I t 59 f l o a t e d on the water s u r f a c e and had the c h a r a c t e r i s t i c s m e l l of l e a f o i l * T h i s demonstrates that some v o l a t i l e s were l o s t i n even the most ge n t l e d r y i n g treatment. The petroleum ether e x t r a c t of lodgepole pine t e c h n i c a l f o l i a g e has a d i s t i n c t i v e green c o l o r . T h i s i n d i c a t e s t h a t some c h l o r o p h y l l and other l i p o p h i l e pigments were e x t r a c t e d by the s o l v e n t , as w e l l * Both bark and t e c h n i c a l f o l i a g e e x t r a c t s , on s t a n d i n g , had the c o n s i s t e n c y of v a s e l i n e g e l ; T h i s suggests that both may c o n t a i n l a r g e p r o p o r t i o n s of wax a l c o h o l s and long c h a i n f a t t y a c i d s . 1.3 A n a l y s i s of Variances f o r Lodgepole Pine Tree P a r t s Petroleum Ether E x t r a c t s In order to d i f f e r e n t i a t e v a r i o u s experimental e f f e c t s , s t a t i s t i c a l means, p a r t i c u l a r l y a n a l y s i s of v a r i a n c e i s a u s e f u l method; As d e s c r i b e d i n the M a t e r i a l and Methods s e c t i o n , the petroleum ether e x t r a c t i o n r e s u l t s with lodgepole pine t r e e p a r t s were determined as both f l a s k weight gains and the thimble content weight l o s s e s . Drying thimbles took a l o n g e r p e r i o d and gave l e s s c o n s i s t e n t r e s u l t s . The f l a s k weight gains could be obtained more e a s i l y and with higher p r e c i s i o n ; Thus, the l a t t e r were used i n the a n a l y s i s of v a r i a n c e . A c c o r d i n g to Table 1, the d i f f e r e n t t r e e p a r t s appeared to give d i f f e r e n t y i e l d s . A n a l y s i s of v a r i a n c e t a b l e s (Tables 2 to 6) are presented according to i n d i v i d u a l t r e e p a r t s , i n the order: Bark; T e c h n i c a l f o l i a g e ; Sapwood; Heartwood; and Cones. 60 1.3.1 Bark Table 2 shows the a n a l y s i s of v a r i a n c e t a b l e f o r lodgepole pine bark samples from two t r e e s subjected t o f o u r d i f f e r e n t drying treatments. The hypotheses t e s t e d here are whether s i g n i f i c a n t d i f f e r e n c e s e x i s t between treatments, t r e e s and the i n t e r a c t i o n of these two f a c t o r s . The r e s u l t s i n d i c a t e that a l l the f a c t o r s are s i g n i f i c a n t l y d i f f e r e n t , i . e . , t h e r e i s l e s s than 1% p r o b a b i l i t y that the e f f e c t s of the f a c t o r s have the same means and standard d e v i a t i o n s . Duncan's m u l t i p l e range t e s t * however, i n d i c a t e s t h a t s p e c i a l f r e e z e - d r y i n g and a i r - d r y i n g gave comparable r e s u l t s . Oven-drying at 70° and 100°C r e s u l t e d i n lower e x t r a c t i v e y i e l d s . 1.3.2 T e c h n i c a l F o l i a g e The a n a l y s i s of v a r i a n c e model f o r t e c h n i c a l f o l i a g e samples i s more complicated than t h a t f o r bark samples, as shown i n Table 3. In t h i s the e f f e c t of d i f f e r e n t p o s i t i o n s i n a t r e e crown i s a nested f a c t o r w i t h i n the t r e e ; The model a l s o shows that there are two i n t e r a c t i o n terms. Because the e f f e c t of crown p o s i t i o n i s s i g n i f i c a n t , the t r e e e f f e c t i s confounded with the p o s i t i o n e f f e c t ; Thus, the t e s t term f o r the t r e e e f f e c t should be the p o s i t i o n f a c t o r . The o v e r a l l e x t r a c t i o n p a t t e r n s are comparable f o r the two t r e e s and a l l the d i f f e r e n c e s are e s s e n t i a l l y due to the p o s i t i o n f a c t o r ; The t a b l e i n d i c a t e s that a l l other f a c t o r s and i n t e r a c t i o n s are s i g n i f i c a n t . Duncan's m u l t i p l e range t e s t shows that each 6 1 drying treatment gave d i f ferent r e s u l t s . Technical fo l i age from the bottom l e v e l of both tree crowns and the top and middle pos i t ions of the E tree gave comparable extract ion r e s u l t s . Technica l fo l i age samples from the top and middle pos i t ions of both tree crowns had higher ex t rac t ive contents than those from bottom p o s i t i o n s . This could r e s u l t from older and less p h y s i o l o g i c a l l y ac t ive components in the lower crown por t ion , even during the tree dormant season when samples were c o l l e c t e d ; The sample a lso had more twigs and branches per unit weight. These r e s u l t s suggest that i t may be poss ib le to obtain within and between tree crown p h y s i o l o g i c a l p r o f i l e s by analyzing var ious ex t rac t ive contents of fo l i age samples from d i f fe ren t pos i t ions i n the crown. 1.3.3 Sapwood Table 4 presents the ana lys is of variance r e s u l t s fo r sapwood samples from two d i f fe ren t pos i t ions of the two tree stems. As in fo l i age extract ion r e s u l t s , the var ia t ion between trees i s l a rge ly the di f ference in pos i t ion e f f e c t s . A l l the other fac tors and in te rac t ions are s i g n i f i c a n t ; There i s no homogeneous subset within the treatment e f fec t and the pos i t ion e f f e c t . 1.3.4 Heartwood Table 5 shows the analys is of variance r e s u l t s for the heartwood samples. Again, a l l the fac tors and in te rac t ions are s i g n i f i c a n t with the exception of tree e f f e c t . Duncan's mult iple 62 range t e s t does not i n d i c a t e any p a i r of treatment e f f e c t s or p o s i t i o n e f f e c t s as comparable. I n t e r e s t i n g l y , sapwood co n t a i n s more e x t r a c t a b l e l i p i d s than the heartwood even during the dormant season; T h i s seems unusual, s i n c e pine heartwoods are known to c o n t a i n more t o t a l e x t r a c t i v e s . The f i n d i n g i s by no means unigue, however, as Anderson e t a l . ( 2 ) noted i n t h e i r study of lodgepole pine terpenes and l i p i d s t h a t the sapwood contained 3.9% ether s o l u b l e f r a c t i o n while the corresponding heartwood sample contained 3.6%. Data from Conner et a l . (26) a l s o suggest t h a t i n some samples, lodgepole pine sapwood has more n o n - v o l a t i l e ether e x t r a c t i v e s than heartwood; They a l s o noted t h a t lodgepole pine heartwood had higher p r o p o r t i o n s of r e s i n a c i d s while sapwood had more f a t t y a c i d s . T h i s i s to be expected, as f a t t y a c i d s o f t e n a s s o c i a t e with l i f e process while r e s i n a c i d s are g e n e r a l l y formed a f t e r wood l o s e s p h y s i o l o g i c a l c a p a b i l i t y . Sometime abundant r e s i n a c i d s are found i n sapwood, however, as a t r e e response to i n j u r y . 1.3.5 Pine Cones The a n a l y s i s of v a r i a n c e r e s u l t s with pine cone data are presented as Table 6. L i k e bark a n a l y s e s , the model had only three terms. The treatment and t r e e e f f e c t s are both s i g n i f i c a n t , while t h e i r i n t e r a c t i o n was not s i g n i f i c a n t . T h i s means that responses due to the d r y i n g treatments f o l l o w s i m i l a r p a t t e r n s f o r the two t r e e s . Duncan's m u l t i p l e range t e s t a l s o i n d i c a t e s t h a t a i r - d r y i n g and 70°C oven-drying gave comparable r e s u l t s . The 63 probable reason f o r s i g n i f i c a n t d i f f e r e n c e s between the f r e e z e - d r i e d sample and the others may be due to l a r g e amounts of v o l a t i l e monoterpenes i n the f r e s h cones which were not w e l l r e t a i n e d by the other d r y i n g treatments. 2 Black Liquor E x t r a c t i o n 2.1 C h a r a c t e r i z a t i o n of BLE Procedures and Results A major o b j e c t i v e of the study was to r e l a t e BLE cooking time-temperatures with e x t r a c t i o n y i e l d s . Before any data analyses were done, v a r i a b l e s of the study had to be i d e n t i f i e d and c h a r a c t e r i z e d * A l s o , f a c t o r s p e r t i n e n t to data c o l l e c t i o n were examined. In t h i s study, cooking times, temperatures and r a t e of temperature r i s e were independent and c o n t r o l l a b l e v a r i a b l e s . F a c t o r s l i k e l i g u o r to m a t e r i a l r a t i o , l i g u o r s t r e n g t h , sample p a r t i c l e s i z e s and d r y i n g technique were s e t . The dependent v a r i a b l e s were BLE r e s u l t s , e i t h e r as t o t a l amount of crude t a l l o i l (TTO) e x t r a c t e d or the amounts of s o l i d m a t e r i a l remaining u n d i s s o l v e d at the end of e x t r a c t i o n ( S o l i d Residue, SR). F a c t o r s that c h a r a c t e r i z e the experimental procedures were: 1) For a l l the cooks, the l i g u o r to m a t e r i a l r a t i o was f i x e d at 7:1, and the l i g u o r a c t i v e a l k a l i was 3.2 and 4.2 g of sodium hydroxide per sample f o r the two l i g u o r s employed; 2) The mode of d i g e s t e r heating using high pressure steam n e c e s s i t a t e s a " r i s e t o temperature" p e r i o d , which co m p l i c a t e s k i n e t i c c a l c u l a t i o n s ; 3) That the screw top s t a i n l e s s s t e e l d i g e s t e r bombs do not g i v e 64 the option of blowing after the cook, nor do they allow s t i r r i n g or liguor c i r c u l a t i o n ; 4) That bomb contents were transferred after cooking to storage containers by spatula, and small sample losses were inev i t a b l e ; 5) That no water was used for the transfer so as not to introduce changes tc the liguor volume, concentration or pH values; 6) That the manual press f i l t e r adapted for the purpose worked reasonably well, but pressure applied was not con t r o l l a b l e . The following observations are made on the experimental r e s u l t s : 1) Even at room temperature there was reaction between lodgepole pine bark or technical foliage and the black liguor, for instance, 38 hr at 25°C (water bath) dissolved 38% of the bark and 33% of the technical foliage fine f r a c t i o n s ; 2) Dissolution of sample materials i n the black liguor might be characterized as having an i n i t i a l fast reaction, followed by a bulk dissolution and f i n a l l y a stage of slow d i s s o l u t i o n , which i s somewhat sim i l a r to kraft d e l i g n i f i c a t i o n ; 3) The data are not ide a l and are flawed by experimental error; 4) Total crude t a l l o i l (TTO) y i e l d for each treatment arises from combination of yie l d results from two li g u o r fractions; 5) Although the Saltsman and Kuiken (132) t a l l o i l determination method adapts very well to analyses of BLE samples, the TTO did show variation and limited r e l a t i o n s h i p to the cooking variables, suggesting that i t i s sensitive to procedural variations; 65 6) The u n d i s s o l v e d s o l i d r e s i d u e (SE) y i e l d s may have l e s s p r a c t i c a l importance, but they showed more c o n s i s t e n t r e l a t i o n s h i p with the BLE cooking v a r i a b l e s ; 7) Due to d i g e s t e r c o n s t r a i n t s and experimental design c o n s i d e r a t i o n s , only f o u r time s e r i e s samples were done at a l l f i v e temperature l e v e l s f o r bark and t e c h n i c a l f o l i a g e ; 8) Because of the " r i s e to temperature" time c o m p l i c a t i o n , i n t e r - t e m p e r a t u r e t i m e - s e r i e s cannot be compared meanfully without f i r s t knowing the r e a c t i o n a c t i v a t i o n energy and f o u r data p o i n t s u s u a l l y do not d e f i n e a r e a c t i o n r a t e s l o p e very w e l l ; 9) The TTO and SR data seem to c o n t a i n s l i g h t s y s t e m a t i c d i f f e r e n c e s f o r e x t r a c t i o n y i e l d s c f the two l i q u o r s t r e n gths; 10) The experimental apparatus rendered the BLE as a s t a t i c p rocess while i n p r a c t i c e d i f f u s i o n mechanisms might become important f a c t o r s i n r a t e d e t e r m i n a t i o n ; 2.2 Development of E m p i r i c a l E x p r e s s i o n s f o r BLE R e s u l t s 2.2.1 K i n e t i c Approaches to the BLE Problem Because of b e t t e r a s s o c i a t i o n with t r a d i t i o n a l p u l p i n g , SR y i e l d s were chosen to e s t a b l i s h e m p i r i c a l expressions between y i e l d s and the time-temperature cooking v a r i a b l e s ; Weston and Schwarz (154) p o i n t e d out that the vast m a j o r i t y of r e a c t i o n s are too complicated to be d e s c r i b e d by t h e o r e t i c a l k i n e t i c s . Thus, c o r r e l a t i o n s developed between k i n e t i c parameters, such as r a t e c o n s t a n t s , a c t i v a t i o n e n e r g i e s and 66 thermodynamic or s t r u c t u r a l c h a r a c t e r i s t i c s of the r e a c t a n t s may provide good e m p i r i c a l r e l a t i o n s h i p s , and these can i n d i c a t e the re a c t a n t property that i s of the g r e a t e s t importance i n determining r e a c t i o n r a t e . They noted t h a t most e m p i r i c a l c o r r e l a t i o n s are between the l o g a r i t h m of the r a t e constant and a f r e e energy change a s s o c i a t e d with one of the r e a c t a n t s . P a n n e t i e r and Souchay (115) di s c u s s e d k i n e t i c s of heterogeneous r e a c t i o n s . They noted that the r a t e of heterogeneous r e a c t i o n must be a p r i o r i a complicated f u n c t i o n of d i r e c t l y measureable parameters, such as temperature and c o n c e n t r a t i o n . Thereby, more complex technigues are i n v o l v e d compared with homogeneous r e a c t i o n s . A l s o the concept of r e a c t i o n order l o s e s s i g n i f i c a n c e i n heterogeneous k i n e t i c s s t u d i e s because even the m o l e c u l a r i t y of r e a c t i n g s p e c i e s i s d i f f i c u l t t o d e f i n e i n a s o l i d . Heterogeneous k i n e t i c s depend on the number and nature of phases. Diverse k i n e t i c b e h a v i o r s are governed i n p a r t by r e l a t i v e d i f f u s i o n r a t e s and i n t e r f a c i a l processes. Because of the m u l t i p i l i c i t y of heterogeneous b e h a v i o r s , many types of heterogeneous r e a c t i o n s have not yet undergone even g u a l i t a t i v e study. The u s u a l k i n e t i c approach to y i e l d and r e a c t i o n parameters i s t o f i r s t e s t a b l i s h r a t e constants at v a r i o u s temperatures, then apply the Arrhenius eguation (Equation [3b]) to f i n d the r e a c t i o n a c t i v a t i o n e n e r g i e s . Knowledge of a c t i v a t i o n e n e r g i e s then a l l o w s an " H - f a c t o r " type of e m p i r i c a l e x p r e s s i o n to be e s t a b l i s h e d (152). The l a c k of exact knowledge on composition of the many 67 r e a c t a n t s i n BLE precludes establishment of a r e a c t i o n mechanism and s t o i c h i o m e t r i c r e l a t i o n s h i p . Emanuel' and Knorre (36) d i s c u s s e d k i n e t i c s of polymer de g r a d a t i o n ; They noted that h y d r o l y s i s , whether a c i d i c , a l k a l i n e or enzymatic, which v i r t u a l l y encompassed a l l p u l p i n g mechanisms, i s a f i r s t - o r d e r r e a c t i o n with r e s p e c t t o polymer bond c o n c e n t r a t i o n . Hence* even though t h e r e might be s u b s t a n t i a l d i f f e r e n c e s i n r e a c t i o n d e t a i l s between BLE and k r a f t d e l i g n i f i c a t i o n , o v e r a l l c h a r a c t e r i s t i c s of the two processes should be comparable, and a f i r s t order r e a c t i o n f o r BLE might be assumed* The f o l l o w i n g r e l a t i o n should then h o l d : kt = ln(a/a-x) [2a] where: k i s the r a t e constant; t i s r e a c t i o n time; a i s the i n i t i a l c o n c e n t r a t i o n of the r e a c t a n t concerned; and x i s the c o n c e n t r a t i o n of the r e a c t a n t at time t . As i s evident from F i g 4 to 6 there are d e v i a t i o n s from a s t r a i g h t l i n e r e l a t i o n s h i p , e s p e c i a l l y with the 120° and 145°C cook data. Faced with t h i s problem, two p o s s i b i l i t i e s are t o : 1) Abandon the f i r s t - o r d e r r e a c t i o n hypothesis and explore the p o s s i b l i l i t y t h a t the r e a c t i o n i s c f higher order; or 2) F i n d a p l a u s i b l e e x p l a n a t i o n f o r the systematic d e v i a t i o n from a f i r s t - o r d e r r e a c t i o n and make necessary c o r r e c t i o n s to the r e a c t i o n parameters. The f i r s t approach was taken, and i t soon became c l e a r t h a t no simple r e a c t i o n order provided a good f i t f o r a l l the data. Small numbers i n the time s e r i e s amplify the problem* Judging 68 from the spread of time s e r i e s data, r e s u l t s from each temperature l e v e l tended to be c l u s t e r e d , i . e . , the data covered only a s m a l l p o r t i o n of the t o t a l r e a c t i o n range. A r e c e n t study by Germgard and Teder (47) on k i n e t i c s of c h l o r i d e d i o x i d e p r e b l e a c h i n g i n c l u d e d "apparent r e a c t i o n o r d e r s " to e x p l a i n pulp kappa number vs. r e a c t i o n time c u r v e s . The temperature dependent apparent r e a c t i o n orders were found to vary from s i x t h to t h i r d orders f o r the temperature range 20 to 80°C. They o f f e r e d the e x p l a n a t i o n t h a t the b l e a c h i n g r e a c t i o n probably c o n s i s t e d of many simultaneous f i r s t order r e a c t i o n s with r e s p e c t to the l i g n i n . They a l s o noted that the r e a c t i o n i s 0.5th order with r e s p e c t to the c o n c e n t r a t i o n of c h l o r i d e d i o x i d e . The apparent r e a c t i o n order approach with i t s temperature dependence would enable good f i t t i n g f o r a l l the data, but the v a l i d i t y and i m p l i c a t i o n of such an approach are not so c l e a r . Higher (n-th) order f i t t i n g a l s o i n v o l v e s the c o n c e n t r a t i o n v a r i a b l e i n r e c i p r o c a l of (n-1) order, which i n t h i s case i s i l l d e f i n e d . On the other hand, i f the probable reason f o r d e v i a t i o n from a f i r s t order r e l a t i o n s h i p i s examined, then i t becomes c l e a r t h a t the f i r s t order assumption on behavior of SR ne g l e c t e d to take r e s i d u a l l i g u o r a l k a l i changes i n t o c o n s i d e r a t i o n . A f i r s t order r e a c t i o n assumes t h a t other r e a c t a n t s are i n excess or at constant c o n c e n t r a t i o n , so t h a t the r a t e depends only on one p a r t i c u l a r r e a c t a n t c o n c e n t r a t i o n . Y l l n e r et a l . (158) pointed out t h a t i n a p u l p i n g process, b e s i d e s d i s s o l u t i o n of m a t e r i a l , t h e r e are a l s o many i n s i t u 69 r e a c t i o n s between l i g u o r and wood components. For i n s t a n c e , xylans have been known to d i s s o l v e i n e a r l y stages of k r a f t p u l p i n g and then r e p r e c i p i t a t e on pulp f i b r e s i n l a t e r r e a c t i o n s ; A l l n o n - d i s s o l u t i o n r e a c t i o n s tend t o complicate p u l p i n g s t u d i e s . They s o l v e d the problem by a p p l y i n g e x t e r n a l l i g u o r c i r c u l a t i o n so as to remove d i s s o l v e d m a t e r i a l and prevent secondary r e a c t i o n s from t a k i n g p l a c e . In t h i s study, however, no such procedure was f o l l o w e d , and there were c e r t a i n l y some a d d i t i o n a l c o m p l i c a t i o n s from the s t a t i c l i g u o r ^ m a t e r i a l c o n d i t i o n s . U n l i k e f u l l s t r e n g t h white l i g u o r s , black l i g u o r s have l i m i t e d a v a i l a b l e a l k a l i ; Approximately 0;3 to 0.4 mole per l i t e r hydroxide i o n remained i n the black l i q u o r a f t e r d i g e s t i o n (60,145). when r a t h e r a c i d i c components l i k e bark or t e c h n i c a l f o l i a g e are added to t h i s r e l a t i v e l y weakly a l k a l i n e l i q u o r , the a l k a l i can be consumed or adsorbed immediately by the s o l i d m a t e r i a l . R e s i d u a l a l k a l i a v a i l a b l e f o r d i s s o l u t i o n processes i s f u r t h e r l i m i t e d ; T h i s phenomenon i s q u i t e e v i d e n t from d i r e c t p o t e n t i o m e t r i c monitoring of BLE at 70°C, as presented i n a l a t e r s e c t i o n . D i s s o l u t i o n of m a t e r i a l i n subsequent cooking may not r e l y e n t i r e l y on c o n t r i b u t i o n s frcm a l k a l i n e h y d r o l y s i s . High temperature h y d r o l y s i s by aqueous medium may play an important r o l e , a l s o , s i n c e bark and t e c h n i c a l f o l i a q e can be e x t r a c t e d t o some extent with hot water (22) . By examininq SR data at v a r i o u s temperatures, some p a t t e r n s can be r e c o g n i z e d . Cooking a t lower temperatures (80° and 100°C) r e p r e s e n t s a s t a t e where the d i s s o l u t i o n process should continue over reasonable time with r e s i d u a l a l k a l i s t r e n g t h s u f f i c i e n t t o 70 maintain a c o n s i s t e n t r a t e . In such cases d e v i a t i o n from f i r s t - o r d e r r e a c t i o n should not be s e r i o u s . At the mid-temperature range (120° to 1450C), however, the m a t e r i a l d i s s o l u t i o n could reach a s t a t e where r e s i d u a l a l k a l i i s almost exhausted and the r a t e slows over the t i m e - s e r i e s . D e v i a t i o n from f i r s t order becomes obvious. The 170°C cook seemed to r e p r e s e n t a f i n a l plateau phase where a d d i t i o n a l time made p r o p o r t i o n a l l y l e s s d i f f e r e n c e as compared to r e s u l t s at lower temperatures. 2.2.2 E m p i r i c a l E x p r e s s i o n s f o r BLE R e s u l t s The p o s s i b l e reasons f o r BLE r e s u l t s d e v i a t i n g from f i r s t - o r d e r k i n e t i c s were noted i n the above s e c t i o n . C e r t a i n b a s i c assumptions have to be e s t a b l i s h e d before attempting e m p i r i c a l e x p r e s s i o n s f o r the BLE r e s u l t s ; Since approximately o n e - t h i r d of the sample m a t e r i a l s were r e a d i l y d i s s o l v e d i n black l i g u o r at 25°C, i . e . , o v e r n i g h t standing of loaded bombs, these p o r t i o n s should be excluded from c o n s i d e r a t i o n i n the r a t e e x p r e s s i o n s . The bases f o r c a l c u l a t i n g the y i e l d s f o r k i n e t i c s were assumed to be 20-g, i n s t e a d of the o r i g i n a l 30-g (0-D weight basis) employed; C e r t a i n temperature time s e r i e s r e s u l t s , l i k e the 170°C cooking of bark samples, seemed to be near the d i s s o l u t i o n l i m i t and were beyond the bulk d i s s o l u t i o n stage, hence, should be excluded from r a t e e x p r e s s i o n s . By d i v i d i n g the SR data with the 20-g weight b a s i s and p l o t t i n g the l o g a r i t h m i c or r e c i p r o c a l transformed SR data a g a i n s t r e a c t i o n time, rate constants f o r bark or f o l i a g e t i m e - s e r i e s could be obtained as f i r s t or second order e x p r e s s i o n s , r e s p e c t i v e l y . I t turned out that i n most cases, second-order e x p r e s s i o n s gave b e t t e r c o e f f i c i e n t s of c o r r e l a t i o n (Fig 5 and 6). The n a t u r a l l o g of second order r a t e c o n s t a n t s seemed t o g i v e more c o n s i s t e n t s l o p e s i n f i t t i n g the Arrhenius equation: In k = InA - E/ET [3b] where: k i s the r a t e constant; A i s a constant; E i s a c t i v a t i o n energy of the r e a c t i o n ; E i s the gas const a n t , or 1.987 cal/mole-K°; and T i s absolute temperature. When the n a t u r a l log of r a t e c o n s t a n t s f o r bark or f o l i a g e time s e r i e s were c o r r e l a t e d with the r e c i p r o c a l of T, the s l o p e s of l i n e a r r e g r e s s i o n f u n c t i o n s thus r e p r e s e n t the apparent e n e r g i e s o f a c t i v a t i o n d i v i d e d by the gas constant: D e t a i l c a c u l a t i o n s of the r e a c t i o n r a t e f o r each time s e r i e s are l i s t e d i n Appendix 4. The Arrhenius p l o t f o r e v a l u a t i n g the apparent e n e r g i e s of a c t i v a t i o n i s presented i n F i g 7. The BLE r e s u l t s were noted e a r l i e r as being i m p r e c i s e due to u n c e r t a i n t y a s s o c i a t e d with manual l i g u o r recovery. I t would be d i f f i c u l t to speculate whether the b e t t e r second-order e x p r e s s i o n s were due to l i g u o r a l k a l i d e p l e t i o n which a l t e r e d the apparent r e a c t i o n order or simply a c o i n c i d e n c e . The apparent e n e r g i e s of a c t i v a t i o n f o r bark (four temperature l e v e l s , e x c l u d i n g the 170°C data) and t e c h n i c a l f o l i a g e ( a l l f i v e temperature l e v e l s ) were 9671 cal/mole and 8812 cal/mole, r e s p e c t i v e l y . These f i g u r e s were much lower than k r a f t p u l p i n g a c t i v a t i o n energy f o r wood c h i p s estimated to be 72 24,000 cal/mole (79) . As F i g 7 i n d i c a t e s , the apparent energies o f a c t i v a t i o n were not i d e a l l y l i n e a r . These f i g u r e s thus only r e p r e s e n t rough approximations f o r the a c t i v a t i o n e n e r g i e s of the temperature range. In many heterogeneous r e a c t i o n s , apparent a c t i v a t i o n e n e r g i e s change with temperature and they may depend on e x t e r n a l c o n d i t i o n s , such as r a t e o f s t i r r i n g and other d i f f u s i o n r e l a t e d parameters (64) . The apparent e n e r g i e s of a c t i v a t i o n f o r bark and t e c h n i c a l f o l i a g e could be used i n a s i m i l a r f a s h i o n as the H-factor c a l c u l a t i o n s (152). To accommodate the lower BLE cooking temperature as compared with the o r d i n a r y k r a f t cooking temperature, the base temperature l e v e l was lowered. Instead of 100°C as adopted i n H-factor c a l c u l a t i o n s , 60°C was chosen as the u n i t r a t e , s i n c e t h i s r e p r e s e n t s a more reasonable l e v e l f o r black l i g u o r m i l l storage. The time-temperature r a t e s c a l e s f o r bark and t e c h n i c a l f o l i a g e at 5°C i n t e r v a l s are presented i n Table 9. These values w i l l be r e f e r r e d as modified H-factor (H»). The estimate f o r each time s e r i e s H 1 - f a c t o r was made by combining the r i s e t o temperature p e r i o d ( t j ) and time at maximun temperature ( t 2 ) H'-values. The t : r a t e f o r each time s e r i e s o f a p a r t i c u l a r m a t e r i a l was the same r e g a r d l e s s of time at maximum temperature. I t soon became apparent t h a t the H'-values tended to under-estimate the s h o r t cooking time r e s u l t s and over-estimate long cooking time r e s u l t s . At t h i s stage i t seemed t h a t there was no re c o u r s e other than a d j u s t i n g the time f a c t o r . In order 73 t o normalize the curve, i t was found through t r i a l and e r r o r that by t a k i n g a 0.45 e x p o n e n t i a l ( s l i g h t improvement over 0.50) f o r the bark at maximum temperature-time and a corresponding 0.333 e x p o n e n t i a l f o r t e c h n i c a l f o l i a g e at maximum temperature-time a b e t t e r c o r r e l a t i o n between the H 1-values and the 20-g weight base SR r e s u l t s c o u l d be e s t a b l i s h e d . P a r t i c u l a r l y , the l o g a r i t h m i c f u n c t i o n of the H 1 - v a l u e s gave good l i n e a r e x p r e s s i o n s f o r y i e l d e s t i m a t e s . The e m p i r i c a l expression f o r lodgepole bark f i n e f r a c t i o n samples cooked with the same l i g u o r to m a t e r i a l r a t i o thus appears as f o l l o w s (n = 16): Y=1 .0812-0.4691[log (t 1H»+t 2 0 -* 5H') ]r (r2=.9509) [5a] where: Y i s the s o l i d r e s i d u e y i e l d based on 20-g 0-D weight; tj^H 1 i s the r i s e - t o - t e m p e r a t u r e r a t e e s t i m a t i o n , without time adjustment and by adding the products of time and mean H'-values at 10°C i n t e r v a l s ; t 2 i s the at-temperature cooking time; and H' i s the r a t e e s t i m a t i o n d e s c r i b e d above. An e x p o n e n t i a l of 0.45 f o r t 2 seemed to r e p r e s e n t the best f i t . I f a more comprehensible sguare root or 0.5 e x p o n e n t i a l was used, then: Y = 1 .0860-0.4722[log ( t 1 H « + t 2 o - 5 H » ) ], ( r 2 = . 9469) [5b] As the ensuing d i s c u s s i o n shows t h i s e x p r e s s i o n seems to r e p r e s e n t a more t y p i c a l k i n e t i c f u n c t i o n . For l o d g e p o l e pine t e c h n i c a l f o l i a g e , the corresponding emperical expression was e s t a b l i s h e d as f o l l o w s (n = 20): 74 Y = 0.941 1-0. 3092[log(t 1H» + t 2 o . 3 3 3 H « ) ] r (r2=.9487) [ 6 ] the d e f i n i t i o n of terms are the same as i n the pre v i o u s e q u a t i o n . These r e s u l t s a r e presented a l s o i n F i g 8. Since H'-values were de r i v e d frcm the r e c i p r o c a l s of the SR y i e l d s f o r second-order r a t e c a l c u l a t i o n , i t was thought t h a t the r e c i p r o c a l might be a b e t t e r v a r i a b l e * The a s s o c i a t e d r e g r e s s i o n eguations f o r bark and t e c h n i c a l f o l i a g e were as f o l l o w s (n = 16 f o r bark and 20 f o r t e c h n i c a l f o l i a g e ) : 1/Y=0.2431 + 1. 4 6 0 5 [ l o g ( t 1 H « + t 2 O - * 5 H i ) ^ ( r2=.9755) [7a] and 1/Y=0.7476+0.8811[log(t lH«+t 2 0. 3 3 3 H « ) ] , ( r2 = . 9798) [ 8 ] The c o e f f i c i e n t s of det e r m i n a t i o n show that 1/Y i s indeed a b e t t e r f i t than Y as dependent v a r i a b l e * The eguations are p l o t t e d i n F i g 9. Again, i f the t 2 e x p o n e n t i a l term of the bark e m p i r i c a l e x p r e s s i o n i s adju s t e d to 0.5, then: 1/Y=1 .086-0. 4722[log(t 1H«+t 2o-s H i ) ] r (r2=.9677) [7b] The e x p r e s s i o n s were reasonably w e l l f i t t e d and could be used to p r e d i c t s o l i d r e s i d u e y i e l d s with f a i r l y h igh degree of co n f i d e n c e . C e r t a i n s y s t e m a t i c d e v i a t i o n s of some data p o i n t s were noted, e s p e c i a l l y f o r f o l i a g e data from 145° and 170°C cooks. These d i s c r e p e n c i e s c o u l d have a r i s e n through d e v i a t i o n s of the r e a c t i o n r a t e s from the Arrhenius f u n c t i o n at those temperatures or n o n - i d e a l H'-value estimates f o r r i s e to temperature p o r t i o n s of the c a l c u l a t i o n . I f a f u r t h e r c o r r e c t i n g f u n c t i o n was used to adjusted r i s e to temperature H'-values, 75 however, t h e ex p r e s s i o n s would become cumbersome; F u r t h e r reasons f o r not a d j u s t i n g the r i s e to maximum temperature time f a c t o r are t h a t : 1) The r e a c t i o n c o n d i t i o n during t h i s p e r i o d was not i s o t h e r m a l , c o n t r a r y to that at maximum temperature; and 2 ) T h i s p e r i o d preceded maximum temperature cooking, and the l i g u o r s t i l l c o n t ained more a l k a l i g i v i n g r e a c t i o n s l e s s a f f e c t e d by a l k a l i d e p l e t i o n . Adopting an e x p o n e n t i a l f a c t o r i n an e x p l o r a t o r y f i r s t study i s u s e f u l , even though an e x p r e s s i o n i n c o r p o r a t i n g an untransformed time term would be e a s i e r to apply. There i s precedence f o r using an e x p o n e n t i a l time term. As example, Luzina (99) found t h a t k r a f t pulp y i e l d was r e l a t e d t o a c t i v e a l k a l i , time at maximun temperature and maximum cooking temperature as: - a T 7 t ° - 4 T 9 1 B = 75(C/10) % where: B i s pulp y i e l d ; C i s a c t i v e a l k a l i c o n c e n t r a t i o n as percent of dry wood; T i s maximum temperature; t i s the cooking time; and a i s a c o e f f i c i e n t depending on r i s e t o maximum temperature time, s u l f i d i t y and the m a t e r i a l ; The f i r s t l e v e l of e x p o n e n t i a l i n the eguation e s s e n t i a l l y p a r a l l e l s the e x p o n e n t i a l terms of the Arr h e n i u s e g u a t i o n , while the temperature and time e f f e c t s were f u r t h e r adjusted with second l e v e l of e x p o n e n t i a l s . P o s s i b l e reasons f o r the need of time f a c t o r adjustment are thought to be a s s o c i a t e d with complicated mass t r a n s p o r t phenomena; In d i s c u s s i o n about heterogeneous k i n e t i c s l i m i t e d by 76 d i f f u s i o n , Pannetier and Souchay (115) noted t h a t f o r cases of a f l u i d a t t a c k i n g the plane s u r f a c e of a s o l i d r e a c t a n t the k i n e t i c e x p r e s s i o n f o r the v a r i a t i o n i n product mass i s a f u n c t i o n of the square ro o t of time, i . e . , an e x p o n e n t i a l of 0.5. This i s c l o s e to the 0.45 e x p o n e n t i a l developed here f o r bark samples. Although i n BLE the bark and f o l i a g e samples are p a r t i c l e s , not plane s u r f a c e s , the macroscopic c o n f i g u r a t i o n i s analogous i n t h a t sample m a t e r i a l was g e n e r a l l y l y i n g s t a t i c a l l y at the bottom of the r e a c t i o n v e s s e l s and the bulk l i g u o r c o n t a c t e d the m a t e r i a l e s s e n t i a l l y on a plane. E s p e c i a l l y , t h e r e are s t a t i c l a y e r s of adsorbed f l u i d molecules surrounding each p a r t i c l e . When these p a r t i c l e s are compacted t o g e t h e r , l i k e i n the BLE c o n d i t i o n , d i f f u s i o n mechanisms c e r t a i n l y play a r o l e i n determining the r e a c t i o n r a t e . 2.2.3 K i n e t i c s with Mass T r a n s f e r Approach to the BLE R e s u l t s I t was p o i n t e d out that treatment of heterogeneous r e a c t i o n s r e g u i r e s c o n s i d e r a t i o n of two f a c t o r s other than those u s u a l l y encountered i n homogeneous r e a c t i o n s : M o d i f i c a t i o n of the k i n e t i c e x p r e s s i o n r e s u l t i n g from the mass t r a n s f e r between phases; and The c o n t a c t i n g p a t t e r n s of the r e a c t i n g phases (97). From a d i s s o l u t i o n r e a c t i o n p o i n t of view, the r e a c t i o n k i n e t i c s might f i t an unreacted core, or s h r i n k i n g core, model. Bowers and A p r i l (16) s t u d i e d 1-butanol d e l i g n i f i c a t i o n of southern yellow p i n e . They noted t h a t n o n c a t a l y t i c r e a c t i o n of p a r t i c l e s with surrounding f l u i d can be c h a r a c t e r i z e d by an unreacted core model. T h e i r model i n c l u d e d terms f o r the d i f f u s i o n of f l u i d phase r e a c t a n t through the l i q u i d f i l m i n t o 77 the p a r t i c l e pore s t r u c t u r e , f o l l o w e d by d i s s o l u t i o n r e a c t i o n s at the a c t i v e s i t e s ; This model was s a i d to represent f l u i d - p a r t i c l e r e a c t i o n s a c c u r a t e l y f o r a wide range of s i t u a t i o n s . Because c o n t a c t i n g areas between the phases were p r o p o r t i o n a l to r e a c t i o n r a t e , the mathematical models developed by L e v e n s p i e l (97) i n c o r p o r a t e d s e v e r a l forms to cover d i f f e r e n t p a r t i c l e shapes. Bower and A p r i l (16) picked a constant s i z e c y l i n d e r i c p a r t i c l e shape model which has the form: t = + ^ t ( l - X ) l n d - X ) + X ] [ 1 0 a ] or, t = k xX + k 2 [ (1-X) In (1-X) + X] [10b] where: t i s r e s i d e n c e time; p i s the d e n s i t y of r e a c t i n g component, i n u n i t of g/cm3; R i s the p a r t i c l e r a d i u s , cm; K i s l i g u i d f i l m t r a n s f e r c o e f f i c i e n t , cm/sec; C i s the c o n c e n t r a t i o n of the s o l v e n t i n the bulk l i g u o r , g/ml; X i s mass of d i s s o l v e d components to the i n i t i a l mass; and Dg i s e f f e c t i v e d i f f u s i t i v i t y i n the p a r t i c l e matrix, cm 2/sec. I f t h i s model i s a p p l i e d to the BLE t i m e - s e r i e s r e s u l t s , with p a r t i c l e s i z e s and d e n s i t i e s comparable to the Bowers and A p r i l (16) study, as f o r the d i f f u s i o n parameters, only the e f f e c t i v e d i f f u s i t i v i t y , D e, was temperature dependent. According to L e v e n s p i e l (97), however, the t o t a l r e a c t i o n time i s the sum of d i f f u s i o n through l i g u i d f i l m c o n t r o l , d i f f u s i o n through rea c t e d l a y e r c o n t r o l and r e a c t i o n c o n t r o l time. Thus, the model has three terms i n s t e a d of two terms as c i t e d i n the Bowers and A p r i l study (16). 78 Absolute temperature e i t h e r as untransformed data or square r o o t s were i n c o r p o r a t e d with the e f f e c t i v e d i f f u s i t i v i t y terms to c o r r e c t f o r the temperature e f f e c t . Again, 20-g weight b a s i s per sample f o r i n i t i a l SP was assumed. The model gave good l e a s t sguare f i t t i n g to i n d i v i d u a l time s e r i e s data. When a l l bark or f o l i a g e time s e r i e s data were used, however, the model f a i l e d ( c o e f f i c i e n t s of determination i n the order of 0.20 f o r the t e c h n i c a l f o l i a g e data and 0.50 f o r the bark data). Thus, an attempt to use a mass t r a n s f e r model with these BLE data was not s u c c e s s f u l . While the k i n e t i c s e x e r c i s e i s f o r m a l l y c o r r e c t , i t c o n t r i b u t e d l i t t l e to b a s i c s c i e n t i f i c understanding or o p p o r t u n i t i e s f o r process c o n t r o l . 2.3 C o r r e l a t i o n s between Crude T a l l O i l Y i e l d s and S o l i d Residues The crude t a l l o i l y i e l d s from BLE were recovered as two f r a c t i o n s . The i n i t i a l f r a c t i o n s represented t a l l o i l soaps t h a t were a l r e a d y d i s s o l v e d i n the bulk black l i g u o r , or i n some a c c e s s i b l e l o c a t i o n s w i t h i n the s o l i d r e s i d u e . These were recovered by manual press f i l t e r i n g of the l i g u o r - s o l i d masses. A p o r t i o n of the o r i g i n a l l i q u o r e n t r a i n e d i n the masses, together perhaps with some t a l l o i l soaps trapped i n l e s s a c c e s s i b l e s i t e s of the s o l i d r e s i d u e s was recovered as second f r a c t i o n s through t h r e e c y c l e s of repeated washing and sgueezing. Probably there were minor amounts of black l i g u o r and t a l l o i l soaps that were not recovered. These were subsequently counted as pa r t of s o l i d r e s i d u e s . 79 Analyses from a l i q u o t s of the i n i t i a l l i q u o r f r a c t i o n s d i d not c o r r e l a t e w e l l with other v a r i a b l e s , i . e . , the TTO and SR data. The combined crude t a l l o i l y i e l d s from the two f r a c t i o n s , however, was c o r r e l a t e d with s o l i d r e s i d u e y i e l d s . These r e s u l t s are presented i n F i g s 10 and 11. C o r r e l a t i o n between TTO and SR f o r the 170°C cooks were concave, i . e . , p r o p o r t i o n a l l y g r e a t e r t a l l o i l y i e l d s were obtained a t higher temperatures. Thus, a l o g a r i t h m i c f u n c t i o n of SR f i t t e d the c o r r e l a t i o n data best. I n c l u d i n g an SR term i n the m u l t i p l e r e g r e s s i o n eguation d i d not improve the c o e f f i c i e n t of c o r r e l a t i o n very much, however. The r e l a t i o n s h i p f o r a l l lodgepole pine bark (n = 45) TTO and the SR data i s d e s c r i b e d by the f o l l o w i n g r e g r e s s i o n eguation: TTO = 17.973 - 6. 628 l o g (SR) ± 0.331, ( r 2 = 0.8271) [11a] where: TTO and SR are expressed i n terms of percent o r i g i n a l m a t e r i a l O-D weight; The corresponding r e l a t i o n s h i p f o r a l l lodgepole pine t e c h n i c a l f o l i a g e data (n = 45) i s : TTO = 17.300 - 7.679 log(SR) ± 0. 290, ( r 2 = 0.8206) [12a] There were notable d i f f e r e n c e s due to l i g u o r s t r e n g t h s . Hence, BLE r e s u l t s from the two l i g u o r s ( o r i g i n a l , N; and r e i n f o r c e d , R) need to be t r e a t e d s e p a r a t e l y . V a r i a t i o n s due to t h i s and other experimental v a r i a b l e s are d i s c u s s e d i n the f o l l o w i n g s e c t i o n s . 80 2.3.1 E f f e c t of P a r t i c l e S i z e Samples r e p r e s e n t i n g three bark and t e c h n i c a l f o l i a g e p a r t i c l e s i z e s (Table 7) were e x t r a c t e d with the two d i f f e r e n t l i g u o r s . The r e s u l t s i n d i c a t e t h a t with few e x c e p t i o n s , f i n e r p a r t i c l e s d i s s o l v e d to a g r e a t e r extent and gave higher t a l l o i l y i e l d s . Sample s i z e g e n e r a l l y a f f e c t e d bark SR and TTO y i e l d s l e s s than f o l i a g e * One p o s s i b l e reason i s that bark p a r t i c l e s have a s p h e r i c a l or d i s c shape and l e s s c o l l a p s e d s t r u c t u r e . Thus, a r e l a t i v e l y s h o r t , u n r e s t r i c t e d d i f f u s i o n path e x i s t s . T e c h n i c a l f o l i a g e , on the other hand, had m i l l e d p a r t i c l e s compressed with p r e f e r e n t i a l o r i e n t a t i o n , i . e . , branches and needles showed f i b e r s o r i e n t e d l o n g i t u d i n a l l y . These samples were c h a r a c t e r i z e d as having a d i s t i n c t i v e s l e n d e r n e s s . During BLE, the t e c h n i c a l f o l i a g e components co u l d be l e s s a c c e s s i b l e to the l i g u o r , and the d i s s o l v e d components c o u l d have g r e a t e r mean d i f f u s i o n paths. For such reasons, more d i s t i n c t SR and TTO d i f f e r e n e c e s r e s u l t e d from p a r t i c l e s i z e d i f f e r e n c e s with t e c h n i c a l f o l i a g e than with the bark. Bowers and A p r i l (16) mentioned the e f f e c t s of p a r t i c l e s i z e and l i g u o r a g i t a t i o n on mass t r a n s f e r processes of d i f f u s i o n r e g i o n s . They noted t h a t s m a l l p a r t i c l e s decreased the importance of d i f f u s i o n through the r e a c t e d zone, while a g i t a t i o n of l i g u o r decreased the importance of d i f f u s i o n a c r o s s l i g u i d f i l m s surrounding the p a r t i c l e s . Under the same no n - a g i t a t e d cooking c o n d i t i o n s o f t h i s study, s m a l l p a r t i c l e s should show the advantage of f a s t e r d i f f u s i o n through the r e a c t i o n zone, while d i f f u s i o n a c r o s s l i g u i d f i l m s was comparable f o r d i f f e r e n t p a r t i c l e s i z e s . 8 1 2.3.2 Cooking Temperature and Storage E f f e c t s V a r i a t i o n s i n t a l l o i l recovery from the 1 0 0 ° and 170°c cooks lowered the c o e f f i c i e n t of d e t e r m i n a t i o n ( r 2 ) . These cooks were done e a r l i e r i n the s e r i e s than cooks at other temperatures (in the order 120°, 1 4 5 ° and 800C) while samples were f r e s h e r . During the two to ten months lapsed time some l i p i d f r a c t i o n s may have degraded or polymerized and become more d i f f i c u l t to e x t r a c t ; D e s p i t e s t o r i n g the samples under n i t r o g e n i n a 2°C c o l d room, slow changes i n some l i p i d s may have occurred l e a d i n g to confounding r e s u l t s . Another p o s s i b l e reason f o r surge i n TTO with r e s p e c t to SR at 170°C may be s m a l l e r p a r t i c l e s i z e which allowed e a s i e r d i f f u s i o n . As d e s c r i b e d most l i p i d s are d i s t r i b u t e d i n c e l l lumina and r e s i n c a n a l s , and become more a c c e s s i b l e as sample p a r t i c l e - s i z e decreases. The 1700c cook may have d i s s o l v e d p a r t i c l e s u f f i c i e n t l y so t hat crude o i l soaps could be recovered more e f f i c i e n t l y . S t i l l another p o s s i b i l i t y i s t h a t l o n g chain f a t t y a c i d s , waxes and s u b e r i n need higher temperatures to e m u l s i f y and s a p o n i f y . Thus, only 170°C cooking c o u l d convert p a r t of these more r e s i s t a n t l i p i d s i n t o s o l u b l e forms. P e a r l (119) found t h a t by b o i l i n g l o b l o l l y pine bark i n 4% sodium hydroxide s o l u t i o n wax components were not s a p o n i f i e d . 2.3.3 E f f e c t of L i g u o r Strength As can be seen from the c o r r e l a t i o n diagrams ( F i g 10 and 11), the o r i g i n a l l i g u o r (N) gave lower SR and TTO values than the c o r r e s p o n d i n g r e i n f o r c e d l i g u o r (R, with 5 g/1 sodium 82 hydroxide added to N). By s e p a r a t i n g each bark and t e c h n i c a l f o l i a g e r e s u l t i n t o two s e t s , a c c o r d i n g to the l i g u o r a l k a l i s t r e n g t h , f o u r separate c o r r e l a t i o n eguations can be obt a i n e d . For bark e x t r a c t e d with N - l i g u o r (n = 15), the eguation i s : TTO = 16.716 - 5. 985 log(SR) ± 0.216, ( r 2 = 0.8899) [11b] the eguation f o r bark e x t r a c t e d with R - l i g u o r , which a l s o i n c l u d e d t i m e - s e r i e s data (n = 30), the equation i s : TTO = 17. 688 - 6.368 log(SR) ± 0.318, ( r 2 = 0.8343) [11c] Sep a r a t i n g the bark data i n t o two subsets improved the c o r r e l a t i o n (compare [11a] a t 0.8271) and reduced standard d e v i a t i o n of the p r e d i c t i o n . For t e c h n i c a l f o l i a g e data (n = 15), samples e x t r a c t e d with N l i q u o r gave the c o r r e l a t i o n eguation: TTO = 7.430 - 0.0647 SR + 0.141, ( r 2 = 0.9375) [12b] and f o r t e c h n i c a l f o l i a g e samples e x t r a c t e d with R - l i g u o r s (n = 30), the f o l l o w i n g equation was f i t t e d : TTO = 17. 480 - 7.746 l o g (SR) ± 0.313, ( r 2 = 0.7963) [12c] In the f i r s t i n s t a n c e , the c o r r e l a t i o n was s u f f i c i e n t l y l i n e a r so that the l o g a r i t h m i c f u n c t i o n of SR was not necessary. T e c h n i c a l f o l i a g e e x t r a c t e d with R - l i g u o r s s u f f e r e d lower r 2 due to removal of a h i g h l y c o r r e l a t e d p o r t i o n of the t o t a l data and some degrees of freedom. Examining the c o r r e l a t i o n matrices showed t h a t l o g a r i t h m i c t r a n s f o r m a t i o n of SR data a c t u a l l y made only s l i g h t improvement 83 to the c o r r e l a t i o n c o e f f i c i e n t s , as compared to using SR d i r e c t l y . Other t r a n s f o r m a t i o n s l i k e r e c i p r o c a l s and sguare r o o t s have a l s o been t r i e d . These d i d not give any stronger v a l u e s . Amounts of t o t a l crude t a l l o i l recovered from t h i s p a r t i c u l a r cooking scheme can be estimated from these equations. A 95% c o n f i d e n c e i n t e r v a l f o r each p r e d i c t i o n can be estimated, a l s o , from the standard d e v i a t i o n a s s o c i a t e d with each c o r r e l a t i o n eguation; 2-3.4 S a p o n i f i c a t i o n and the BLE R e s u l t s In the L i t e r a t u r e Review, e x t e n s i v e r e f e r e n c e was made t o s a p o n i f i c a t i o n ; T h i s i n f o r m a t i o n r e l a t e s d i r e c t l y t o the present BLE r e s u l t s . S a p o n i f i c a t i o n and f a t h y d r o l y s i s which are the main pathways f o r r e c o v e r i n g crude t a l l o i l soap by BLE, are e i t h e r exothermic or i n v o l v e no heat o f r e a c t i o n (74,136,140). Thermodynamically, these r e a c t i o n s can occur spontaneously or need no e x t e r n a l energy t o proceed. K i n e t i c a l l y , however, the r e a c t i o n r a t e s are temperature dependent; As noted by Lascaray (90), the r a t e of f a t h y d r o l y s i s i s temperature dependent i n the sense t h a t d i f f u s i o n r a t e s of the r e a c t a n t s are temperature dependent. Fat h y d r o l y s i s reaches an e q u i l i b r i u m based on the c o n c e n t r a t i o n r a t i o of r e a c t a n t s and products (92,104,142). Amounts of combined f a t t y a c i d s i n bark or f o l i a g e are r a t h e r minute. T h e r e f o r e , the trace'amount of g l y c e r o l l i b e r a t e d d u r i n g BLE should not h i n d e r the r e a c t i o n from proceeding to completion. E s p e c i a l l y i n an a l k a l i n e s o l u t i o n the competing 84 s a p o n i f i c a t i o n r e a c t i o n i s i r r e v e r s i b l e , and should always d r i v e the r e a c t i o n t o completion. S a p o n i f i c a t i o n i s known to be a second order r e a c t i o n with r a t e ^dependent on c o n c e n t r a t i o n s of both r e a c t a n t s . When bark or t e c h n i c a l f o l i a g e was added to the black l i g u o r , the a c i d i c components r e a c t e d with l i g u o r a l k a l i and consumed part of the a v a i l a b l e a l k a l i * As noted above, a l k a l i c o n c e n t r a t i o n was l i m i t e d and competition f o r a v a i l a b l e a l k a l i may have depended on a c i d d i s s o c i a t i o n c o n s t a n t s . Resin and f a t t y a c i d s are r e l a t i v e l y strong a c i d s compared with p h e n o l i c substances which do not c o n t a i n c a r b o x y l groups. Hence, i n a co m p e t i t i o n f o r a l k a l i , some bark and f o l i a g e l i p i d s should have more f a v o r a b l e r e a c t i o n r a t e s than d i s s o l u t i o n of l i g n i n and p h e n o l i c s . Some l i p i d f r a c t i o n s , l i k e waxes and longer c h a i n f a t t y a c i d s are not so r e a c t i v e . T h e i r d i s s o l u t i o n depends on m i c e l l e formation (124,126). The m i c e l l a r c h a r a c t e r i s t i c s of t a l l o i l soaps were d i s c u s s e d p r e v i o u s l y . One p o t e n t i a l problem a s s o c i a t e d with BLE i s t h a t d e p l e t i o n of a v a i l a b l e l i g u o r a l k a l i may render incomplete soap s e p a r a t i o n . C o n v e n t i o n a l wisdom i n d i c a t e s t h a t i t i s necessary to maintain a c e r t a i n l i g u o r a l k a l i s t r e n g t h to f a c i l i t a t e soap s e p a r a t i o n (138). Laboratory a n a l y s e s of black l i g u o r s can gi v e i n f o r m a t i o n as to t a l l o i l amounts, but i t provides no c l u e as to how w e l l the t a l l o i l soap would separate; T h i s problem i s by no means insurmountable, s i n c e by simply a d j u s t i n g the l i g u o r to m a t e r i a l r a t i o , s u f f i c i e n t a l k a l i can be maintained while e f f e c t i v e BLE can be p r a c t i c e d . BLE may provide an a d d i t i o n a l advantage to t a l l o i l l i g u o r 85 soap s e p a r a t i o n i n one aspect: The o p t i m a l s o l i d contents f o r t a l l o i l soaps to separate from c o n v e n t i o n a l black l i q u o r i s around 25 to 27% (35). I f l i t t l e wash water i s used a f t e r the BLE cook, then the a d d i t i o n a l d i s s o l v e d m a t e r i a l w i l l i n c r e a s e the l i q u o r s o l i d content toward such optimal c o n c e n t r a t i o n . The temperature c o n d i t i o n s employed i n BLE (80° to 170°C) should have achieved reasonable s a p o n i f i c a t i o n ; However, the recovery of t a l l o i l soaps depends not only on degree of s a p o n i f i c a t i o n , but a l s o to a l a r g e extent on d i s s o l u t i o n of matrix m a t e r i a l s and the means of l i g u o r s e p a r a t i o n . Q u a l i t a t i v e comparisons between BLE r e s u l t s and sodium hydroxide s o l u t i o n s c o n t a i n i n g egual amounts of a c t i v e a l k a l i i n the same c o c k i n g schemes i n d i c a t e t h a t the presence of sodium s u l f i d e i n black l i g u o r s gave b e t t e r d i s s o l u t i o n of m a t e r i a l and higher t a l l o i l y i e l d s than sodium hydroxide s o l u t i o n alone. By improving recovery technigue g r e a t e r t a l l o i l y i e l d s with l e s s cooking should be p o s s i b l e . A Russian study (14) on dynamics of t a l l o i l e x t r a c t i o n during k r a f t pulping i n d i c a t e d that the amount of t a l l o i l recovered was time dependent: F u r t h e r , combined pulp and l i g u o r e x t r a c t i v e s and f a t t y to r e s i n a c i d p r o p o r t i o n s were constant as compared t o the o r i g i n a l contents i n wood. Resin and f a t t y a c i d compositions underwent changes d u r i n g the cook; Unsaturated a c i d s and r e s i n a c i d s decreased while o l e i c a c i d i n c r e a s e d i n p r o p o r t i o n . An o p t i m a l h e a t i n g scheme could be modelled, given the p r o p o r t i o n s and values of the products and the c o s t s of energy and chemical l o s s e s . 86 2.4 E l e c t r o c h e m i c a l Monitoring of BLE The c o l d l i g u o r pH change a f t e r cooks was recorded with the i n t e n t i o n of r e l a t i n g these data to TTO and SR v a l u e s . The measurements were not c o n s i s t e n t , however, and were notably a f f e c t e d by post-cooking storage and p r e s s - f i l t e r i n g ; T h i s , n e v e r t h e l e s s * prompted an i n t e r e s t i n the p o s s i b i l i t y of a p p l y i n g e l e c t r o c h e m i c a l technigues to BLE. In order to f o l l o w r e a c t i o n k i n e t i c s during the cook, c e r t a i n parameters must be e s t a b l i s h e d ; As i n d i c a t e d i n the l i t e r a t u r e , v a r i a b l e s l i k e e f f e c t i v e a l k a l i , s u l f i d i t y , sample s i z e and p a r t i c l e morphology c o u l d a f f e c t the r a t e of black l i g u o r e x t r a c t i o n , b e s i d e s the time-temperature e f f e c t s . To stop the r e a c t i o n every once i n a while and take l i g u o r samples f o r a n a l y s i s i s i m p r a c t i c a l ; E l e c t r o c h e m i c a l means, e s p e c i a l l y p o t e n t i o m e t r i c measurements using pH e l e c t r o d e s and s p e c i a l i o n e l e c t r o d e s l i k e sodium and s u l f i d e would give continuous monitoring of the r e a c t i o n . However, the e l e c t r o c h e m i c a l technigue i s not without c o n s t r a i n t s . The pH e l e c t r o d e s do not work too w e l l under s t r o n g l y a l k a l i n e c o n d i t i o n s : Sodium i o n s tend to compete with the r a r e hydrogen i o n s i n b i n d i n g to the g l a s s s u r f a c e and thereby cause "sodium e r r o r " i n the measurement. There i s a l s o a problem a s s o c i a t e d with high temperature. Most e l e c t r o d e s have an aqueous e l e c t r o l y t e s o l u t i o n as i n t e r n a l r e f e r e n c e . Under high temperature c o n d i t i o n s , water tends t o evaporate and cause change i n r e f e r e n c e s o l u t i o n c o n c e n t r a t i o n s ; T h i s i s e s p e c i a l l y true with l i g u i d - j u n c t i o n e l e c t r o d e s . The maximun working temperature f o r most e l e c t r o d e s i s , t h e r e f o r e , around 100°C. Even at t h i s 87 r e l a t i v e l y low cooking temperature, u s e f u l i n f o r m a t i o n might s t i l l be gathered as the r e a c t i o n proceeds. 2.4.1 Background L i g u o r pH has l o n g been r e c o g n i z e d as an important v a r i a b l e i n v a r i o u s p u l p i n g processes. Each process u s u a l l y e n t a i l s an optimal pH range. Measuring pH thus p r o v i d e s a convenient means, f o r monitoring l i g u o r c o n d i t i o n s ; Because cooking l i g u o r s c o n t a i n v a r i o u s e l e c t r o l y t e s which i n t e r a c t with each other i n a complicated manner, the a c t i v i t y of a s i n g l e ion s p e c i e s i s profoundly a f f e c t e d by other e l e c t r o l y t e s p e c i e s . I f these i n t e r a c t i o n s are not taken i n t o account, the s o - c a l l e d pH measurements may have very l i t t l e p r a c t i c a l meaning; Ingruber and A l l a r d (71) s t u d i e d pH at cooking temperatures of the s u l f i t e process c o v e r i n g a c o l d l i g u o r pH range of 1 to 12.5. They noted t h a t at high cooking temperatures, hot pH values d i f f e r e d c o n s i d e r a b l y from those at the c o l d pH. They co n s i d e r e d l i g u o r pH as the most important parameter i n s u l f i t e p u l p i n g . A s l i g h t v a r i a t i o n i n the l i g u o r pH c o u l d cause profound changes i n the r e s u l t s and i t was considered necessary to know the at-temperature pH i n s t e a d of merely c o l d l i q u o r pH. N e v e r t h e l e s s , pH alone can not provide enough i n f o r m a t i o n on cooking l i g u o r chemistry to enable automatic feedback c o n t r o l ; Mostly i n the l a s t decade, s p e c i a l i o n - s e l c t i v e e l e c t r o d e s capable of measuring the a c t i v i t i e s of v a r i o u s c a t i o n s and anions other than hydrogen i o n , have g r a d u a l l y a t t a i n e d popular acceptance (116,137). T h e i r a p p l i c a t i o n i n k r a f t p u l p i n g c o n t r o l 88 has been e s t a b l i s h e d (96,116,146). Among these, Lenz and Mold (96) d i s c u s s e d the use of a sodium i o n s e l e c t i v e e l e c t r o d e f o r k r a f t p u l p i n g l i g u o r measurements. Advantages of sodium i o n e l e c t r o d e s a r e : 1) L i t t l e tendency f o r sodium to form a complex; 2) Low hydrogen i o n i n t e r f e r e n c e at pH v a l u e s above 9.5; and 3) Low s p e c i f i c i t y f o r other mono-valent c a t i o n s . In e l e c t r o c h e m i s t r y , the c o n v e n t i o n a l c o n c e n t r a t i o n u n i t i s Molal, M, which i s c o n c e n t r a t i o n i n mole per kilogram of s o l v e n t . One normal sodium hydroxide thus corresponds to 1.019 M. A l s o , e l e c t r o c h e m i s t r y deals with the a c t i v i t i e s of i o n i c s p e c i e s not the c o n c e n t r a t i o n d i r e c t l y . Thus the a c t i v i t y c o e f f i c i e n t s of a p a r t i c u l a r i o n at v a r i o u s molal c o n c e n t r a t i o n s need to be known. One of the most important eguations i n e l e c t r o c h e m i s t r y i s the Nernst eguation, which has the form: where: E i s the measured e.m.f.; E° i s the constant of p a r t i c u l a r h a l f - c e l l r e a c t i o n ; R i s the gas constant, 8.314 v o l coulomb/KO/mole; T i s the absolute temperature; n i s the number of e l e c t r o n s i n v o l v e d i n the h a l f - c e l l r e a c t i o n ; F i s Faraday, or 96,493 coulombs; and [ A ] , [ B ] , e t c . are a c t i v i t i e s of the r e a c t a n t s and products r a i s e d to the a p p r o p r i a t e s t o i c h i o m e t r i c powers. [c ] [ D ] . . . [ A ] [ B ] . . . [13] 2.4.2 C h a r a c t e r i z i n g Black Liguor by E l e c t r o c h e m i c a l Means Mainly due to the dark, opague nature of the black l i g u o r , 89 standard t i t r a t i o n methods i n v o l v e d i f f i c u l t y i n determining end p o i n t s . E l e c t r o c h e m i c a l methods have been developed and are adopted i n TAPPI standard methods T625-ts-64 (147) . In t h i s study, the black l i g u o r a c t i v e a l k a l i and sodium s u l f i d e d e terminations were done f o l l o w i n g t h i s TAPPI procedure. 2.4.2.1 A c t i v e A l k a l i Determination A t y p i c a l curve f o r the black l i q u o r a c t i v e a l k a l i d e t e r m i n a t i o n i s shown i n F i g 12. Such p l o t s g i v e some i n d i c a t i o n as to r e s i d u a l a l k a l i c o n t e n t s , when used l i g u o r pH was compared with the t i t r a t i o n curve. T h i s * however, could r e s u l t i n s u b s t a n t i a l e r r o r because b u f f e r i n g c o n d i t i o n s of BLE l i g u o r s and t h a t of the standard samples are not the same. A l s o , the nature of the curve was such t h a t i t s f l a t p o r t i o n d i d not vary much with a d d i t i o n of a c i d , i . e . , correspondence between pH and m i l l i e q u i v a l e n t of r e s i d u a l a l k a l i was poor. LeMon and Teder (94) i n t h e i r study of k r a f t p u l p i n q k i n e t i c s t i t r a t e d black l i q u o r a q a i n s t standard HC1 s o l u t i o n and took pH 11 as the e f f e c t i v e a l k a l i e q u i v a l e n t . However, they d i d not give d e t a i l s of the procedures i n v o l v e d : 2.4.2.2 Sodium S u l f i d e Determination When s i l v e r n i t r a t e standard s o l u t i o n i s added to the black l i g u o r sample, s i l v e r s u l f i d e p r e c i p i t a t e s are formed. The s u l f i d e i o n c o n c e n t r a t i o n decreases as a r e s u l t . The change i n s u l f i d e p o t e n t i a l can be detected with a s i l v e r - s i l v e r s u l f i d e e l e c t r o d e using a pH e l e c t r o d e f o r r e f e r e n c e (15). F i g 13 shows the a r g e n t i m e t r i c r e s u l t s of 10 ml a l i g u o t s of 90 three black l i q u o r samples t i t r a t e d with 0.1 N standar d s i l v e r n i t r a t e s o l u t i o n . Curve A i s the t i t r a t i o n curve of an unoxi-d i z e d b l a c k l i q u o r sample, while C and B are curves f o r o x i d i z e d black l i q u o r s with and without a d d i t i o n of an ammonia b u f f e r , r e s p e c t i v e l y . The l i q u o r s u l f i d e has a s t r o n g tendency to o x i d i z e ; L i g u o r exposed t o a i r f o r prolonged p e r i o d s w i l l l o s e s u b s t a n t i a l p o r t i o n s of the s u l f i d e , as Curve C shows. A l s o , i n an unbuffered c o n d i t i o n (Curve B) the t i t r a t i o n r e s u l t can be e r r a t i c and with obscure end p o i n t . The i n f l e c t i o n p o i n t f o r Curve A i s not very sharp. Swartz and L i g h t (146) obtained comparable r e s u l t s to t h a t shown i n F i g 13. They a t t r i b u t e d the drawn-out curve c h a r a c t e r i s t i c of the slow r e l e a s e of s u l f i d e from o r g a n i c and other s o u r c e s , such as methyl mercaptan and dimethyl s u l f i d e . The f i r s t i n f l e c t i o n p o i n t , t h e r e f o r e , should mark the i n o r g a n i c s u l f i d e e g u i v a l e n t . The sodium s u l f i d e c o n c e n t r a t i o n of the black l i g u o r ( l i g u o r N) was found to be 0.092 mole per l i t e r . Combining the r e s u l t s from a c t i v e a l k a l i d e t e r m i n a t i o n , the e f f e c t i v e a l k a l i c o n c e n t r a t i o n i s shown to be: 0.40 - 0.092/2 = 0.35 m o l e / l i t e r . E f f e c t i v e a l k a l i o f the l i g u o r s thus became 0;35 mole/1 and 0.48 mole/1 f o r l i g u o r s N ( o r i g i n a l ) and B ( r e i n f o r c e d ) , r e s p e c t i v e l y . E f f e c t i v e a l k a l i c o n c e n t r a t i o n i s g e n e r a l l y considered a u s e f u l parameter i n p u l p i n g c o n t r o l (61,130). 2.4.3 D i r e c t Potentiometry As noted above, the c o n c e n t r a t i o n s of e l e c t r o l y t e s are not d i r e c t l y u s e f u l i n e l e c t r o c h e m i s t r y . The a c t i v i t y c o e f f i c i e n t of 91 each s i n g l e ion at a p a r t i c u l a r c o n c e n t r a t i o n needs to be known. I t was suggested (96) that as an a l t e r n a t e , the ion s t r e n g t h a d j u s t o r (ISA) can be used. A 20 to 5 0 - f o l d excess c o n c e n t r a t i o n of n o n - i n t e r f e r i n g i o n i c s p e c i e s can be added to both the standard and t e s t s o l u t i o n s to swamp out the v a r i a t i o n s i n i o n i c s t r e n g t h between them. T h i s method can provide more r e l i a b l e r e s u l t s , but i s a p p l i c a b l e only when the o b j e c t i v e of measurement i s to o b t a i n accurate sodium ion c o n c e n t r a t i o n with d i s r e g a r d f o r a l l other e l e c t r o l y t e s i n the l i g u o r . For the BLE process, t h i s i s not p r a c t i c a l , s i n c e simultaneous monitoring of both sodium i o n a c t i v i t y and pH are necessary. A d d i t i o n of ISA would d i l u t e the l i g u o r and change the b u f f e r c o n d i t i o n f o r pH measurements* A more p a i n s t a k i n g process as presented by Swartz (145) was adopted f o r the study. The sodium i o n a c t i v i t i e s at v a r i o u s molal c o n c e n t r a t i o n s were obtained from r e f e r e n c e s of K i e l l a n d (77) and Bates et a l . ( 9 ). These v a l u e s were g e n e r a l l y d e r i v e d from i o n i c hydration t h e o r i e s , and on a s i n g l e ion a c t i v i t y b a s i s . Thus, they are only approximations of a c t u a l a c t i v i t i e s i n complex e l e c t r o l y t e c o n d i t i o n s . In order to keep t r a c k of pH p o t e n t i a l changes more e a s i l y , the e l e c t r o d e output i n m i l l i v o l t s was recorded i n s t e a d of the c o n v e n t i o n a l pH v a l u e s . Correspondence between the two s c a l e s can be e s t a b l i s h e d by b r a c k e t i n g the measurement range with standard s o l u t i o n s of known pH. In t h e o r y , hydrogen a c t i v i t y d i f f e r e n c e s of one order of magnitude cause a 59.16 m i l l i v o l t s change a t 25°C, and a corresponding one u n i t change i n the pH s c a l e . 92 2.4.3.1 C a l i b r a t i o n L i n e s f o r D i r e c t Potentiometry A. Temperature C o r r e c t i o n In Swartz's study, a remote double j u n c t i o n r e f e r e n c e e l e c t r o d e was used t o provide c o n s i s t e n t e.m.f. output. Since the i n n e r chamber e l e c t r o l y t e was kept at constant 25°C temperature, there was no need f o r r e f e r e n c e output adjustment. In t h i s study, however, the double j u n c t i o n e l e c t r o d e (Orion 90-02-00) was i n s e r t e d i n the r e a c t i o n v e s s e l and t h i s made d i r e c t c o n t a c t with the t e s t s o l u t i o n s ; The observed temperature c o e f f i c i e n t s f o r pH and sodium i o n e l e c t r o d e s were confounded with the r e f e r e n c e e l e c t r o d e output changes. By comparing the pH and sodium i o n e l e c t r o d e e;m.f. outputs to the d o u b l e - j u n c t i o n e l e c t r o d e at 25° and 70OC, the temperature c o e f f i c i e n t s f o r the e l e c t r o d e s can be obtained. Temperature c o e f f i c i e n t s of the pH and sodium i o n s e l e c t i v e e l e c t r o d e s were found to be 2.06 and 0;62 millivolts/°C, r e s p e c t i v e l y . The t h e o r e t i c a l values f o r the temperature c o e f f i c i e n t s can be c a l c u l a t e d from the Nernst equation (Eg. [ 1 3 ] ) , a l s o , s i n c e the eguation c o n t a i n s a temperature term. T h i s was not done, however, as very l i t t l e p r a c t i c a l values i s added; Since the r e f e r e n c e e l e c t r o d e p r o v i d e s c o n t r o l e.m.f. f o r both the pH and sodium ion e l e c t r o d e s , v a r i a t i o n s due to temperature change or random d r i f t can be d i f f e r e n t i a t e d from the c h a r t s . B; C o r r e c t i o n f o r L i q u i d - J u n c t i o n P o t e n t i a l 93 The r e f e r e n c e e l e c t r o d e has a l i g u i d - j u n c t i o n , or s a l t b r i d g e , i n c o n t a c t with the t e s t s o l u t i o n . P o t e n t i a l b u i l d s up a cross the j u n c t i o n , which a f f e c t s e l e c t r o d e output. When t e s t s o l u t i o n s of d i f f e r e n t c o n c e n t r a t i o n or composition are used, the l i q u i d - j u n c t i o n p o t e n t i a l s a l s o change. In many i n s t a n c e s , t h i s c o r r e c t i o n was omitted. S u b s t a n t i a l e r r o r i n measurements cou l d happen as a consequence* To c o r r e c t f o r t h i s change i n p o t e n t i a l , the Henderson eguation ( 8 ) i s used: E (j ) = BT ( U l - V I ) - (U2 - V2) TJj. ' + V i « F (U] ' + V i ' ) - ( U 2 I + V 2 , « ) l n M j 2 ' '.+ V 2 ' - [ 14 ] T h i s complicated l o o k i n g eguation c o n t a i n s terms of l i m i t i n g i o n i c c o n d u c t i v i t y of t o t a l c a t i o n s and anions i n the r e f e r e n c e e l e c t r o d e f i l l i n g s o l u t i o n and the t e s t s o l u t i o n . In the e guation, E(j) i s the l i g u i d j u n c t i o n p o t e n t i a l , R, T and F are the same as i n the Nernst eguation (Eq. [ 1 3 ] ) , U i and V ^ are l i m i t i n g i o n i c c o n d u c t i v i t i e s of a l l c a t i o n s and anions i n s o l u t i o n i , r e s p e c t i v e l y , and U ^ and V ± • are l i m i t i n g i o n i c c o n d u c t i v i t i e s of a l l c a t i o n s and anions i n s o l u t i o n i , without regard t o the p o l a r i t y of charges; The l i m i t i n g i o n i c c o n d u c t i v i t y value f o r each ion s p e c i e s can be found i n the book by Harned and,Owen (56). E i t h e r c o n c e n t r a t i o n s of the e l e c t r o l y t e s i n moles/1 ( 8 ), or more a p p r o p r i a t e l y the a c t i v i t i e s of the e l e c t r o l y t e s (145), can be used to c a l c u l a t e the t o t a l c o n d u c t i v i t i e s . When the values were s u b s t i t u t e d i n the equation and the S o l u t i o n 1 was taken as the r e f e r e n c e e l e c t r o l y t e , and S o l u t i o n 2 as the t e s t s o l u t i o n , the c o r r e c t e d sodium p o t e n t i a l s were used to c o n s t r u c t the c a l i b r a t i o n l i n e ; F i g 14 shows the 94 c a l i b r a t i o n l i n e based on standard sodium hydroxide s o l u t i o n s . Data of o r i g i n a l o b s e r v a t i o n s and c a l c u l a t e d l i g u i d - j u n c t i o n p o t e n t i a l s are presented i n Table 10. C o r r e c t i o n of l i g u i d - j u n c t i o n p o t e n t i a l e f f e c t e d the p r a c t i c a l l y i d e a l s t r a i g h t l i n e r e l a t i o n s h i p . The p o t e n t i a l change f o r one order of magnitude d i f f e r e n c e i n a c t i v i t y was 53.45 m i l l i v o l t s . T h i s i s s l i g h t l y l e s s than the Nernst constant of 59.16 m i l l i v o l t s at 25oc. C. C o r r e c t i o n f o r Sodium E r r o r Before the c a l i b r a t i o n l i n e f o r pH output can be c o n s t r u c t e d , sodium e r r o r of the pH p o t e n t i a l needs to be c o r r e c t e d . Swartz (145) noted t h a t hydroxide i o n c o n c e n t r a t i o n i t s e l f , without r e f e r e n c e to i t s source (sodium hydroxide or sodium s u l f i d e ) , u l t i m a t e l y determines the values of e f f e c t i v e a l k a l i . I f i t was not f o r the sodium e r r o r e f f e c t of the pH e l e c t r o d e , a c o n v e n t i o n a l pH e l e c t r o d e could be used to determine the e f f e c t i v e a l k a l i r a t h e r e a s i l y . The c o r r e c t i o n can be done by comparing the e f f e c t of 1 M a d d i t i o n a l sodium ions cn the pH p o t e n t i a l of a 0.1 M sodium hydroxide s o l u t i o n . The l i g u i d - j u n c t i o n p o t e n t i a l s have to be c o r r e c t e d , as w e l l . The sodium e r r o r c o r r e c t i o n i n v o l v e s c a l c u l a t i o n of a s e l e c t i v i t y c o e f f i c i e n t f o r the pH e l e c t r o d e K H N a - Sodium e r r o r i s assumed to be n e g l i g i b l e i n s o l u t i o n s c o n t a i n i n g l e s s than 0.1 molal of sodium, i . e . , no c o r r e c t i o n needed f o r standard s o l u t i o n c o n c e n t r a t i o n s of 0.1 M or l e s s . Only c o r r e c t i o n f o r 1 M s o l u t i o n was needed. 95 A f t e r these s e t s of c o r r e c t i o n s , the c a l i b r a t i o n l i n e f o r the pH p o t e n t i a l i s presented as F i g 15 and the observed hydroxide p o t e n t i a l and c o r r e c t e d hydroxide p o t e n t i a l s are a l s o presented i n Table 10. Thus, the p o t e n t i a l change f o r one order of magnitude d i f f e r e n c e i n hydroxide a c t i v i t y was 64.1 m i l l i v o l t s . T h i s i s s l i g h t l y g r e a t e r than the Nernst constant of 59.16 m i l l i v o l t s at 25oc. 2.4.3.2 D i r e c t Potentiometry of the Black Liguor and the BLE A. The Black Liguor The pH and sodium ion a c t i v i t y measurements i n the o r i g i n a l black l i g u o r of t h i s study i n d i c a t e d t h a t hydroxide i o n c o n c e n t r a t i o n was i n the order of 0.40 mole/1, while sodium i o n c o n c e n t r a t i o n was 0.73 mole/1; Because the black l i g u o r e l e c t r o l y t e composition was not known, the l i g u i d ^ j u n c t i o n c o r r e c t i o n has to be assumed to be the same as 1.0 M standard s o l u t i o n , which was c l o s e to the black l i g u o r measurements. Adopting the 18.6 m i l l i v o l t l i g u i d - j u n c t i o n p o t e n t i a l , the hydroxide i o n c o n c e n t r a t i o n was comparable to t h a t estimated by the TAPPI standard method T625-ts-64. Once the parameters of the black l i g u o r and i t s temperature v a r i a t i o n s have been e s t a b l i s h e d the stage i s set f o r d i r e c t p o t e n t i o m e t r i c monitoring of BLE. B. The BLE When bark or f o l i a g e f i n e f r a c t i o n samples were added to a preheated black l i g u o r there were instantaneous sharp decreases 96 i n hydroxide p o t e n t i a l (complement of pH p o t e n t i a l , i . e . , a decrease i n pH v a l u e ) . Sodium i o n p o t e n t i a l a l s o decreased t o some ex t e n t , but much l e s s i n magnitude (Fig 16). T h i s i n d i c a t e d a n e u t r a l i z a t i o n by the a v a i l a b l e a l k a l i of a c i d i c components i n these m a t e r i a l s and a l s o some a d s o r p t i o n phenomena. In some case, p a r t i c u l a r l y when l i g u o r c i r c u l a t i o n was poor, the hydroxide p o t e n t i a l showed a s l i g h t rebound a f t e r the f i r s t hour or so of cooking. T h i s i s probably due to hydroxide i o n d i f f u s i o n i n the v i c i n i t y of the e l e c t r o d e * The ge n e r a l trend was continuous d e c l i n e i n hydroxide p o t e n t i a l over time. The decrease was l i n e a r , i n d i c a t i n g t h a t consumption of a l k a l i was c l o s e to a slow f i r s t order c o n d i t i o n because p o t e n t i a l changes with the l o g a r i t h m c f a c t i v i t y , a l i n e a r change i n p o t e n t i a l thus t r a n s l a t e s i n t o an e x p o n e n t i a l a c t i v i t y change. There were only s l i g h t changes i n sodium i o n p o t e n t i a l over time, i f the d r i f t was c o r r e c t e d . In a few runs there were s e r i o u s d r i f t s up to 20 m i l l i v o l t s i n magnitude. These were thought to o r i g i n a t e from the r e f e r e n c e e l e c t r o d e p o t e n t i a l , as both sodium and pH p o t e n t i a l s were a f f e c t e d i n a s i m i l a r f a s h i o n . T h i s problem c o u l d be d e a l t with i n p a r t by changing the f i l l i n g s o l u t i o n s of the r e f e r e n c e e l e c t r o d e a f t e r the cook, and double checking the f i n a l p o t e n t i a l measurements to c o r r e c t e r r o r s due to the d i l u t i o n of the i n t e r n a l f i l l i n g s o l u t i o n . D r i f t s due to thermal e f f e c t s , which could not be p i n p o i n t e d afterward* were more troublesome. One sapwood sample was a l s o t e s t e d ( F i g 16). As expected, immediately a f t e r adding to the black l i g u o r a marked decrease 97 i n hydroxide p o t e n t i a l was noted; Within an hour or so, however, there was a s t r o n g rebound of hydroxide p o t e n t i a l . T h i s i s probably due to hydroxide ion d i f f u s i o n and d e s o r p t i o n from wood. The d i f f e r e n c e s i n behavior between wood, bark and t e c h n i c a l f o l i a g e c o u l d be due t o i n t r i n s i c a c i d i t y d i f f e r e n c e s of these m a t e r i a l s . Sapwood i s much l e s s a c i d i c than e i t h e r bark or t e c h n i c a l f o l i a g e , hence, i t can not r e t a i n the hydroxide i o n without undergoing chemical r e a c t i o n . At the experimental temperature of 70<>C, most of the k r a f t p u l p i n g r e a c t i o n s with wood would not take p l a c e , e s p e c i a l l y with the lower a l k a l i n i t y of black l i g u o r . The hydroxide ions o r i g i n a l l y adsorbed on wood matrices were r e l e a s e d g r a d u a l l y causing the rebound i n hydroxide p o t e n t i a l . The pH p o t e n t i a l s of f i n a l s o l u t i o n s , as compared with the o r i g i n a l l i g u o r pH, i n d i c a t e d a drop i n hydroxide i o n c o n c e n t r a t i o n s of almost three orders of magnitude; F i n a l l i g u o r hydoxide c o n c e n t r a t i o n s were roughly 0.02 mole/1 f o r the sapwood and 0.002 mole/1 f o r bark and t e c h n i c a l f o l i a g e . The d e p l e t i o n of a v a i l a b l e a l k a l i i n the ambient l i g u o r does not n e c e s s a r i l y c o r r e l a t e to the recovered l i g u o r pH from BLE, nor does i t repre s e n t the working a l k a l i c o n c e n t r a t i o n i n the BLE process. Most l i k e l y , s u b s t a n t i a l amounts of hydroxide were adsorbed by the m a t e r i a l or held w i t h i n the p a r t i c l e s and, t h e r e f o r e , were not a v a i l a b l e to d i r e c t potentiometry measurements; When l i g u o r was recovered by press f i l t e r i n g the m a t e r i a l s a f t e r BLE, some of the a l k a l i c o u l d then be recovered. The hydroxide i o n c o n c e n t r a t i o n during and a f t e r the d i r e c t potentiometry were estimated from the pH p o t e n t i a l and c o r r e c t e d 98 f o r sodium e r r o r . F i g 16 shows the pH and sodium e l e c t r o d e p o t e n t i a l s by BLE d i r e c t potentiomery with r e s p e c t to r e a c t i o n time. The p o t e n t i a l s shown were at temperature p o t e n t i a l s c o r r e c t e d f o r d r i f t . D i r e c t potentiometry of BLE was not s t u d i e d e x t e n s i v e l y . L i m i t e d data did not allow examining the r e l a t i o n s h i p s between SR or TTO and c o r r e c t e d pH p o t e n t i a l s of f i n a l s o l u t i o n s . The r e s u l t s are l a r g e l y q u a l i t a t i v e . B a s i c a l l y , the experiment does demonstrate use of d i r e c t potentiometry i n monitoring the BLE process, as long as the temperature of the process does not exceed the o p e r a t i o n a l temperature of the e l e c t r o d e s . S e v e r a l problems a s s o c i a t e d with the setup were detected. As noted above, the r e f e r e n c e e l e c t r o d e p o t e n t i a l tended to d r i f t under experimental c o n d i t i o n s . To counter the problem, a remote d o u b l e - j u n c t i o n r e f e r e n c e e l e c t r o d e with p r e s s u r i z e d e x t e r n a l c e l l might avoid most of the d r i f t problem* Such a e l e c t r o d e c o u l d have the i n t e r n a l r e f e r e n c e s o l u t i o n kept at constant temperature, while the p r e s s u r i z e d e x t e r n a l c e l l c o u l d counter vapor pressure and prevent c o n c e n t r a t i o n change of the f i l l i n g s o l u t i o n . Some s p e c i a l i o n s e l e c t i v e e l e c t r o d e s give an unstable b a s e l i n e which renders t h e i r prolonged use u n r e l i a b l e . 2.5 P o t e n t i a l s and C o n s t r a i n t s of BLE The complete t r e e u t i l i z a t i o n (CTU) concept has been s t i m u l a t e d by recent m a t e r i a l , economic* environmental and energy c o n s t r a i n t s . F o r e s t resource demand p r o j e c t i o n s have 99 sounded alarm on wood and f i b e r s u p p l i e s i f c u r r e n t u t i l i z a t i o n methods are not improved. One study (75) p r o j e c t e d a s h o r t f a l l of about 0.2 b i l l i o n c u b i c meters of wood on 3.8 b i l l i o n c u b i c meters world demand by A.D. 2000. But through f u l l - t r e e and f u l l - f o r e s t u t i l i z a t i o n , which i n c l u d e s a l l above-ground t r e e components and a l l t r e e s , i t i s p o s s i b l e to r e l i e v e the s h o r t f a l l . 2.5.1 Complete Tree U t i l i z a t i o n and BLE Fordyce (45) s t u d i e d CTU p o t e n t i a l with lodgepole p i n e . He noted that y i e l d of wood f i b r e can be r a i s e d by at l e a s t o n e - t h i r d through residue u t i l i z a t i o n . Furthermore* c o s t s of s k i d d i n g whole t r e e s t o l a n d i n g s appeared t o be no gr e a t e r than the c o s t s of s k i d d i n g only the merchantable p o r t i o n s . O v e r a l l a p p r a i s a l of near-complete u t i l i z a t i o n of lodgepole pine i n d i c a t e d s i g n i f i c a n t environmental b e n e f i t s as w e l l . At present, complete t r e e h a r v e s t i n g g e n e r a l l y i n v o l v e s whole t r e e c h i p p i n g or t r e e s h e a r e r / p u l l e r . Whatever the h a r v e s t i n g methods, before the whole t r e e resource can be pro p e r l y u t i l i z e d , some s o r t i n g of the components i s necessary. E v e n t u a l l y , v a r i o u s r e s i d u e s may s t i l l p i l e up a t l o g g i n g s i t e s or m i l l s . T h e i r u t i l i z a t i o n or d i s p o s a l becomes an acute problem. T h i s has prompted more e x t e n s i v e s t u d i e s i n recent years on v a r i o u s aspects o f re s i d u e u t i l i z a t i o n . The most b a s i c approach i s to c o n s i d e r r e s i d u e m a t e r i a l s as p o t e n t i a l f u e l f o r making wood i n d u s t r i e s s e l f - s u f f i c i e n t i n energy supply. There are a l s o numerous s t u d i e s e x p l o r i n g the p o s s i b i l i t y of using r e s i d u e m a t e r i a l f o r making s t r u c t u r a l boards, adhesive 100 f o r m u l a t i o n s and through v a r i o u s chemical c o n v e r s i o n s to produce chemical raw m a t e r i a l s . I t i s beyond the scope of t h i s t h e s i s to d i s c u s s r a m i f i c a t i o n s of a l l the v a r i o u s residue uses. Some s t u d i e s t h a t i n v o l v e d u t i l i z a t i o n of pine barks, however, are p e r t i n e n t t o BLE o b j e c t i v e s and should be de s c r i b e d * As the L i t e r a t u r e Review i n d i c a t e s , lodgepole pine bark has not been s t u d i e d very e x t e n s i v e l y . One reason i s probably t h a t the r e l a t i v e l y t h i n bark accounts f o r only a smal l p r o p o r t i o n of the t o t a l t r e e biomass (134). Information on i t s u t i l i z a t i o n i s even harder to come by. Chow (23) s t u d i e d the use of lodgepole pine bark as m a t e r i a l f o r bark board without adding s y n t h e t i c r e s i n s . The board was found to have s i m i l a r s t r e n g t h and dimensional s t a b i l i t y to Type I e x t e r i o r grade wood p a r t i c l e b o a r d s . Some attempts t o e x t r a c t lodgepole pine bark p o l y f l a v o n o i d s have been presented i n the L i t e r a t u r e Review (4,63). Hemingway (62) d i s c u s s e d the prospect of u t i l i z i n g c o n i f e r o u s bark p o l y f l a v o n o i d s as adhesive agents; He noted that t o t a l y i e l d of aldehyde r e a c t i v e m a t e r i a l was much higher when the bark was e x t r a c t e d with an a l k a l i n e s o l u t i o n r a t h e r than water. A l k a l i n e e x t r a c t s have been used commonly as m a t e r i a l f o r r e s i n f o r m u l a t i o n . Carbohydrate contamination of p h e n o l i c s can cause s u b s t a n t i a l l o s s i n bond s t r e n g t h . A d d i t i o n of m i n e r a l a c i d t o the a l k a l i n e e x t r a c t s o l u t i o n should help p r e c i p i t a t e p o l y f l a v o n o i d s while e x c l u d i n g most carbohydrates: Sodium hydroxide s o l u t i o n a l s o e x t r a c t s wax and suberin which could i n t e r f e r e with adhesion. Weyerhaeuser r e s e a r c h e r s have s t u d i e d 101 recovery of waxy m a t e r i a l s from a l k a l i n e e x t r a c t s (32). Such processes could lead to good q u a l i t y bark e x t r a c t s f o r adhesive f o r m u l a t i o n and pro v i d e a source of wax compounds. More r e s e a r c h i s needed as t o means of p u r i f y i n g bark e x t r a c t s and c o n t r o l l i n g of o x i d a t i o n and/or rearrangement r e a c t i o n s , BLE could serve as a p a r a l l e l process i n r e c o v e r i n g p h e n o l i c resources from barks. 2.5.2 Some C o n s t r a i n t s on BLE Any v i a b l e process has to be p r o f i t a b l e . Even with no i n t e n t i o n s of doing a c o s t - b e n f i t a n a l y s i s , c e r t a i n c o n s i d e r a t i o n s a r i s e as t o f a c t o r s f a c i n g adoption of BLE. Some of these o b s e r v a t i o n s f o l l o w . 1) T r a n s p o r t a i o n of r e s i d u e s from f o r e s t s to m i l l s i t e s ; Barks g e n e r a l l y do not present much problem, s i n c e they may be t r a n s p o r t e d i n t a c t or i n pa r t with the l o g s to the m i l l . No a d d i t i o n a l c o s t i s i n v o l v e d i n the t r a n s p o r t a i o n , unless s p e c i a l p r e c a u t i o n s are needed to minimize bark l o s s e s . T e c h n i c a l f o l i a g e , on the other hand, i s not much used. E f f i c i e n t trimming, packaging and moving of these m a t e r i a l s needs t o be developed; Recently developed machines (112) capable of s t r i p p i n g the f o l i a g e o f f Scots pine t h i n n i n g s and trimming the tops from p r i n c i p a l f e l l i n g s to c o l l e c t f o l i a g e i s a p o s i t i v e development i n t h i s d i r e c t i o n . 2) Some storage p r a c t i c e s add water to bark. T h i s excess water i n c r e a s e s energy demand by adding water to the process. 3) S i z e of m a t e r i a l f o r e x t r a c t i o n . D i v i s i o n of m a t e r i a l i n t o f i n e p a r t i c l e s f a c i l i t a t e s e x t r a c t i o n as shown i n t h i s study, 102 but t h i s a l s o i n c u r s a d d i t i o n a l energy c o s t s . 4) D e p l e t i o n of l i g u o r a l k a l i c o u l d cause p r e c i p i t a t i o n of d i s s o l v e d organic substances and c l o g g i n g of tubes during the ev a p o r a t i o n stage* Otherwise* e x t r a c t e d r e s i d u e s could cause problems u n l e s s removed from the stream. 5) Bark and/or f o l i a g e crude t a l l o i l s obtained by BLE may d i f f e r i n composition as compared with c o n v e n t i o n a l wood t a l l o i l s . Hence, d i f f e r e n t r e f i n i n g and marketing may be necessary. 6) E f f i c i e n t methods need to be developed to separate l i g u o r from s o l i d r e s i d u e s as completely as p o s s i b l e * F o r t u n a t e l y , the process i s f a i r l y robust; Besides the cooking time-temperature r e l a t i o n s h i p s d e s c r i b e d i n the study, p a r t i c l e s i z e might be t r a d e - o f f with time. M a i n t a i n i n g e f f e c t i v e a l k a l i s t r e n g t h by white l i g u o r or sodium hydroxide a d d i t i o n c o u l d be repl a c e d by i n c r e a s i n g time or a d j u s t i n g the l i g u o r t o m a t e r i a l r a t i o ; Other o p p o r t u n i t i e s w i l l a r i s e . When the b e n e f i t from by-products could j u s t i f y the c o s t , l i g u o r might be d i v e r t e d f o r such purposes and make-up chemical purchased i n s t e a d (31). B e t t e r l i g u o r s e p a r a t i o n technigues f o r removing e x t r a c t e d p a r t i c l e s (SR) can be p e r c e i v e d , such as c e n t r i f u g i n g and r o l l e r p ress with/without vacuum s u c t i o n . 3 Recommendations C e r t a i n recommendations are made f o r f u r t h e r BLE s t u d i e s as: 1. Employing a cooking f a c i l i t y capable of f a s t temperature r i s e and l i g u o r c i r c u l a t i o n to s i m p l i f y k i n e t i c c o n s i d e r a t i o n s ; 103 2. Extending each t i m e - s e r i e s over l o n g e r time i n t e r v a l s with mere samples; 3. A n a l y s i n g the composition of the BLE crude t a l l o i l and l i g n i n f r a c t i o n s ; and 4. A p p l y i n g BLE to t r e e p a r t s from other s p e c i e s , p a r t i c u l a r l y those with r i c h l i p i d or p h e n o l i c c o n t e n t s , l i k e western hemlock and balsam f i r barks. 104 V CONCLUSION 1. The BLE concept was o r i g i n a t e d and t e s t e d f o r the f i r s t time. T h i s process was shown to be a v i a b l e means f o r r e c o v e r i n g u s e f u l components frcm tree r e s i d u e s . 2. Petroleum ether e x t r a c t i o n of l odgepole pine bark and t e c h n i c a l f o l i a g e was used t o give g u a n t i t a t i v e i n f o r m a t i o n on p o t e n t i a l crude t a l l o i l (TTO) y i e l d s from these m a t e r i a l s . The r e s u l t s matched c l o s e l y the y i e l d s obtained by BLE cooking. 3. L i g u o r with 5 g/1 sodium hydroxide added was more e f f i c i e n t i n TTO e x t r a c t i o n and SR y i e l d r e d u c t i o n than the o r i g i n a l l i g u o r . 4. The s o l i d r e s i d u e (SR) y i e l d s had complicated k i n e t i c r e l a t i o n s h i p s to cooking time-temperature. By making some assumptions the r e a c t i o n c o n d i t i o n seemed to approach second order k i n e t i c s and e m p i r i c a l e x p r e s s i o n s are given. 5. The TTO y i e l d s were c o r r e l a t e d to the l o g a r i t h m i c f u n c t i o n of SR y i e l d s , mainly due to the y i e l d surge at h i g h e r tempera-t u r e s , i . e . , 1700 and 145<>c vs 1200, 1000 and 80<>c. 6. M a t e r i a l p a r t i c l e s i z e i n f l u e n c e d TTO and SR y i e l d s . T e c h n i c a l f o l i a g e samples e x h i b i t e d a more d i s t i n c t p a t t e r n i n t h i s regard than bark samples. T h i s was a t t r i b u t e d to p a r t i c l e morphology f o l l o w i n g m i l l i n g . 7. D i r e c t potentiometry was used to assess black l i g u o r components a t low temperature. The technigue might be developed f u r t h e r f o r s t u d y i n g r e a c t i o n parameters and m o n itoring the BLE process. 105 VI LITERATURE CITED 1. Alen, R. , P a t j a , P. and E. Sjostrom. 1979. Carbon d i o x i d e p r e c i p i t a t i o n of l i g n i n from pine k r a f t b l a c k l i g u o r . T appi 62 (1 1) : 108-1 10. 2. Anderson, A. B., R i f f e r , R. and A. Wong; 1969. Chemistry o f the genus Pinus. VI. Monoterpenes, f a t t y and r e s i n a c i d s of Pinus c o n t o r t a and Pinus a t t e n u a t a . Phytochem. 8(12): 2401-2403. 3. Anon. 1950. Bark s t u d i e s : Lodgepole pine bark; Rep. Ore. St. F o r e s t . . 1948/49-1949/50: 65-66. 4. Anon. 1980. Pinus c o n t o r t a D. Douglas ex Loudon; Davidsonia 1 0 (4): 75-83. 5. A r r h e n i u s , S. 1926. The p h y s i c a l chemistry of wood-cellulose p r e p a r a t i o n . Paper Trade J . 82(15): 65-66. 6. Back, E. 1951. S o l u b i l i z a t i o n phenomena during the d i s s o l u t i o n of re s i n o u s m a t e r i a l i n pulp and papermaking; Svensk P a p p e r s t i d . 54(19): 657-662. 7. Barton, G. M. and B. F. MacDonald. 1977. New look at f o l i a g e chemicals; Tappi 61(1): 45-48. 8. Bates, R. G. 1973. In Determination o f pH. John Wiley and Sons, New York. pp. 36-38. 9. Bates, R. G., S t a p l e s , B. R. and R. A. Robinson. 1970. I o n i c h y d r a t i o n and s i n g l e i o n a c t i v i t i e s i n unas s o c i a t e d c h l o r i d e s at high i o n i c s t r e n g t h s . Anal. Chem. 42(8): 867-871. 10. Bauer, T. W. and R. M. Dorland. 1954. Thermodynamics of the combustion of sodium-based p u l p i n g l i g u o r s . Can. J . Technol. 32(3): 91-101. 11. B e r g e l l , C. 1926; S a p o n i f i c a t i o n methods i n the l i g h t of the modern s a p o n i f i c a t i o n theory. Z. Deut. O l - F e t t - I n d . 46: 737-738, 753-754, 769-770 ( c f . CA 21: 830). 12. Bespyatov, M. P. and V. I. P o l s t y a n o i ; 1964. K i n e t i c s of f a t h y d r o l y s i s a t high temperatures i n the presence of a l k a l i n e c a t a l y s t . I I . Maslob. - z h i r . Prom. 30(4): 19-22. ( c f . CA 65: 20378) 13. B h a t t a c h a r j e e , M. K. and N. G. Wagle; 1964. F a t - s p l i t t i n g — - i t s mechanism and k i n e t i c s . Indian O i l Seed J . 8 (4) : 285-8. 106 14. B i l y u b a , T. S. and E. V. Bogdanova. 1975. Balance and dynamics of e x t r a c t i n g r e s i n o u s substances during the k r a f t p u l p i n g process. G i d r o l i z . Lesokhim; Prom. No. 1: 14-16 (O r i g . Not seen, c f * ABIPC 46: 1653). 15. Borlew, P. B. and T. A. Pascoe. 1946. P o t e n t i o m e t r i c d e t e r m i n a t i o n of sodium s u l f i d e i n s u l f a t e pulp black l i g u o r . Paper Trade J . 122(10): 31-34. 16. Bowers, G. and G. C. A p r i l . 1977. Agueous n-butanol d e l i g n i f i c a t i o n of southern yellow pine; Tappi 60(8): 102-104. 17. Boyette, S. R., J r . 1977. T a l l o i l and t u r p e n t i n e y i e l d s are seen decreasing a t southern (U.S.) m i l l s . Pulp Paper 51 (4) : 78-80. 18. B r a t t , L. C; 1979. Wood-derived chemicals: Trends i n prod u c t i o n i n the U.S. Pulp Paper 53(6): 102-108. 19. Braun, J . V. and F. F i s c h e r . 1933. S t e r i c hindrance. VII. E s t e r i f i c a t i o n and s a p o n i f i c a t i o n from the standpoint of the e l e c t r o n i c theory of union. Ber. 66B: 101-104 ( c f . CA 27: 1613). 20. Bray, M. W. and J . S. M a r t i n . 1941. Pulping sweetgum by a l k a l i n e processes; I . E f f e c t of cooking v a r i a b l e s on y i e l d and pulp g u a l t i y . Tech; Assoc; Papers. 24: 251-263. 21. Chang, Y-P. 1954. Anatomy of common North American pulpwood barks. TAPPI Monograph S e r i e s No. 14, pp 64-68. 22. Chang, Y-P. and R. L. M i t c h e l l . 1955. Chemical composition of common North American pulpwood barks. Tappi 38(5): 315-320. 23. Chow, S. 1975. Bark boards without s y n t h e t i c r e s i n s ; F o r e s t Prod; J . 25 (1 1) : 32-37. 24. C h r i s t i a n s , D. T., Leandro, S., Look, M., N o b e l l , A. and T. S. Armstrong. 1970. Process f o r producing p o l y o x y a l k y l e n e e t h e r p o l y o l s from l i g n i n . U.S. pat. 3,546,199. 25. C h r i s t o v , Tz., V a l t c h e v , VI., S t o i l k o v , G., Veleva, S t . and E. Valtcheva; 1971. K i n e t i c s of the s u l f a t e p u l p i n g p r o c e s s . C e l l u l o s e Chem. Technol. 5(1): 93-98. 26. Conner, A. H., D i e h l , M. A. and J . W. Rowe; 1980. T a l l o i l p r e c u r s o r s i n three western p i n e s : Ponderosa, lodgepole, and limber pine: Wood S c i . 12(3): 183-191. 27. C o r r i n , M. L. and W. D. Harkins. 1947. The e f f e c t of s a l t s on the c r i t i c a l c o n c e n t r a t i o n f o r the formation of m i c e l l e s i n c o l l o i d a l e l e c t r o l y t e s . J . Am. Chem. Soc. 69: 683-688. 107 28. Cox, B. D., Owen, H. M. and R. R. F u l l e r ; 1960. Commercial p u l p i n g by t o t a l chemical using elemental s u l f u r i n the d i g e s t e r . Tappi 43(10): 163A-167A. 29. C r i t c h f i e l d , W. B. 1979. The d i s t r i b u t i o n , g e n e t i c s , and s i l v i c s of lodgepole pine. In Proc; I n t : Onion F o r e s t . Res. Organ. Vancouver, B.C. V o l . 1, pp 65-94. 30. D i l l e n , S. and S. Noreus. 1967. I n f l u e n c e o f s u l f i d i t y and a l k a l i charge i n k r a f t and p o l y s u l f i d e p u l p i n g of Scots p i n e . Svensk P a p p e r s t i d . 70(4): 122-134. 31. Dolenko, A. J . and M. R. C l a r k e . 1978. Resin binders from k r a f t l i g n i n . F o r e s t Prod. J . 28 (8): 41-46. 32. Dowd, L. E., Br i n k , D. L., Gregory, A. S; and A. K. E s t e r e r . 1966. F r a c t i o n a t i o n of a l k a l i n e e x t r a c t s of t r e e barks. U.S. Pat. No; 3,255,221. 33. Eckey, E. W. 1954. In Vegetable Fats and O i l s ; I n t e r s c i e n c e , New York. pp. 138-139. 34. E k w a l l , P., Mandell, I. and K. F o n t e l l ; 1968. Ternary systems of sodium c a p r y l a t e and water with ethylene g l y c o l , g l y c e r o l , and t e t r a e t h y l e n e g l y c o l . J . C o l l o i d I n t e r f a c e S c i . 28(2): 219-226. 35. E l l e r b e , R. W. 1973. Why, where, and how U.S. m i l l s recover t a l l o i l soap. Paper Trade J . 157(26): 40-43. 36. Emanuel* E. M. and D. G. Knorre, 1973. In Chemical K i n e t i c s , t r a n s . Kondor, R., ed. S l u t z k i n , D., John Wiley and Sons, New York; pp. 387-389. 37. E n k v i s t , T. 1957. Determinations of the consumption of a l k a l i and s u l f u r at v a r i o u s stages of s u l f a t e , soda, and a l k a l i n e and n e u t r a l s u l f i t e d i g e s t i o n of spruce wood. Svensk P a p p e r s t i d . 60 (17): 616-620. 38. E n k v i s t , T. 1975. K r a f t or soda black l i g u o r adhesive and procedure f o r making the same: U.S. Pat; 3,864,291. 39. E r i k s o n , M. and C. W. Dence. 1975. Y i e l d and composition of t a l l o i l from o x y g e n - a l k a l i pulped thermomechanical f i b e r . T appi 58 (8): 190. 40. E r i n s , P., C i n i t e , V. and I. M. V i t o l a ; 1972. K i n e t i c s of the changes i n the chemical composition, s t r u c t u r e , and p r o p e r t i e s of birchwood caused by agueous s o l u t i o n s of ammonia. Deposited P u b l i : VINITI 4624-72, 29 pp ( O r i g . not seen, c f . CA 85: 34833). 41. E r i n s , P., C i n i t e , V., Jacobsons, M. and J . G r a v i t i s . 1976. Wood as a multicompcnent, c r o s s - l i n k e d polymer system. In Proc; Eighth C e l l u l o s e Conf. Appl. Polymer symp. No. 28. V o l . 3. ed. T i m e l l , T. E;, John Wiley and Sons, New York. 108 pp. 1117-1138. 42. F e l t o n , E. W. 1953. A study of the b o i l i n g process and a m i l l a p p l i c a t i o n . World Paper Trade Rev. 140(15): 1095-1096. 43. F i e l d , L., Drummond, P. E* and E. A. Jones; 1958; The o r g a n i c chemistry of s u l f u r i n the k r a f t process. I I . Nature of the s u l f u r l i n k a g e s i n pine t h i o l i g n i n ; Tappi 41 (12): 727-733. 44. F i e l d * L., Drummond, P. E., R i g g i n s , P. H. and E; A; Jones. 1958. The o r g a n i c chemistry of s u l f u r i n the k r a f t p r o c e s s . I; Pine t h i o l i g n i n as a mixture; Tappi 41(12) : 721-727. 45. Fordyce, D. H. 1972. Realism of l o g g i n g r e s i d u e s - - u t i l i z a t i o n or d i s p o s a l ? In Proc. S i x t h P a r t i c l e b o a r d Symp ed. Maloney, T. M., Pullman, Wash. pp 215-232. 46. F o r r e s t , G. I . 1977. I d e n t i f i c a t i o n of unknown lodgepole pine o r i g i n s ; Res; Info; Note, F o r e s t r y Comm. U.K. No. 30, 4 pp. 46. Germgard, U. and A. Teder. 1980. K i n e t i c s o f c h l o r i n e d i o x i d e p r e b l e a c h i n g . Pulp and Paper Canada 81(6): T31-T36. 48. G o l d s t e i n , I; S. 1975. P o t e n t i a l f o r c o n v e r t i n g wood i n t o p l a s t i c s . Science 189(4206): 847-852. 49. G o l d s t e i n , I. S. 1978. Wood may r e p l a c e o i l as source f o r chemical i n d u s t r y raw m a t e r i a l . World Wood 19(10): 35-36. 50. Golubchik, E. M. 1974. Method of r e c o v e r y i n g sodium from black l i g u o r of the p u l p i n g i n d u s t r y . Izu VUZ, Lesnoi Zh. 17(1): 166-167 (Orig; not seen* c f . ABIPC 45: 3814). 51. Grace, T. M. 1976. P e r s p e c t i v e s on recovery technology. In Forum on K r a f t Recovery A l t e r n a t i v e s . I n s t . Of Paper Chemistry, Appleton, Wis. pp 27-57. 52. G r a v i t i s , J . , E r i n s , P., S t o l d e r e , I; and H; Z e l e r t e . 1976. K i n e t i c s of the a l k a l i n e h y d r o l y s i s of e s t e r bonds i n wood. Khim. Drev. 1976(1): 21-28 (Orig; not seen, c f ; CA 84: 123640) . 53. Gupta, R. C. and V. K. Sehgal. 1979. E f f e c t of v i s c o s i t y and molecular weight of l i g n i n ^ f o r m a l d e h y d e r e s i n on the glue-adhesion s t r e n g t h of plywood. H o l z f o r s c h . Holzverwert. 31(1): 7-9. 54. Hannus, K. 1976. L i p o p h i l i c e x t r a c t i v e s i n t e c h n i c a l f o l i a g e of pine (Pinus s y l y e s t r i s ) . In A p p l i e d Polymer Symposium No. 28. V o l . 3. ed. T i m e l l , T. E., John Wiley and Sons, New York. pp.485-501. 109 55. Harkins, W. D., Brown, F; E; and E. C. H; Davies. 1917. Surface t e n s i o n (v). S t r u c t u r e of s u r f a c e s of l i q u i d s , and s o l u b i l i t y as r e l a t e d to work done by a t t r a c t i o n of two l i q u i d s u r f a c e s as they approach each other. J . Am. Chem. Soc. 39: 354-364. 56. Harned, H. S. and B. B. Owen. 1958. In The P h y s i c a l Chemistry of E l e c t r o l y t i c S o l u t i o n s . Reinhold, New York. p. 231. 57. H a r t l e r , N. 1962. P e n e t r a t i o n and d i f f u s i o n r e l a t i o n s h i p d u r i n g s u l f a t e cooking. P a p e r i Puu 44(7): 365-374. 58. H a r t l e y , G. S. 1949. Organized s t r u c t u r e i n soap s o l u t i o n s . Nature 163: 767-768. 59. Hartman, L. and R. 0. Weenink. 1967. A note on the f a t t y a c i d composition of the l i p i d s from the bark of Pinus r a d i a t a . N.Z. J . S c i . 10 (3): 636-638. 60. Hattbn, J . V. 1973. Survey of c u r r e n t p r a c t i c e s i n l i g u o r a n a l y s e s i n Canadian a l k a l i n e pulp m i l l s . Pulp Paper Mag. Can. 74 (5) : 102-105. 61. Hatton, J . V. 1973. Development of y i e l d p r e d i c t i o n e g u ations i n k r a f t p u l p i n g . Tappi 56(7): 97-100. 61a. Hatton, J . V. and J. L. Keays. 1973. E f f e c t of c h i p geometry and moisture on y i e l d and g u a l i t y of k r a f t pulps from western hemlock and black spruce. Pulp Paper Mag. Can. 74 (1) : 79-87. 62. Hemingway, R. W. 1978. Adhesives from southern pine b a r k — a review of past and c u r r e n t approaches to r e s i n f o r m u l a t i o n problems: In Complete Tree U t i l i z a t i o n of Southern Pine. ed. M c M i l l i n , C. W. , FPRS Publ. Madison, Wis. pp. 443-457. 63. Hergert, H. L. 1956. The f l a v o n o i d s of lodgepole pine bark. J . Org. Chem. 21 (5): 534-537. 64. H i l l s , C; G., J r . 1973. In An I n t r o d u c t i o n to Chemical E n g i n e e r i n g K i n e t i c s and Reactor Design. John Wiley and Sons, New York. pp. 527-536. 65. Holmbom, B., Gadda, L. and R. Ekman. 1979. T a l l o i l c o n s t i t u e n t s i n soda and k r a f t p u l p i n g ; Tappi 62(8): 119-120. 66. Hougberg, B. and T. E n k v i s t . 1954. I n v e s t i g a t i o n of i n o r g a n i c s u l f u r compounds i n s u l f a t e black l i g u o r s . P a p e r i Puu 36 (10): 381-386. 67. Howard, E. T. 1976. F a t t y and waxy components of southern pine bark—amount present as f r e e e x t r a c t i v e s . USDA F o r e s t Ser. Res. Note SO-204, 4 pp. 110 68. Hoyt, C. H. and D i W. Goheen. 1971. Polymeric products. In L i g n i n s ; ed. Sarkanen, K. V. and C. H. Ludwig, W i l e y - I n t e r s c i e n c e , New York; pp. 833-840. 69. Hsu, 0. H. H. and W. G. G l a s s e r . 1975. Polyurethane foams from c a r b o x y l a t e d l i g n i n s . J . Appl. Polymer S c i ; , Appl. Polymer Symp. 28: 297-307. 70. Hunt, K. and A. Kuechler, 1970. Chemical a n a l y s i s of A t r o p e l l i s \ p i n i p h i l a ] c a n k e r - i n f e c t e d lodgepole pine. Bi-monthly Res. Notes. Can. F o r e s t r y Ser. 26 (2): 59. 71. Ingruber, 0. V. and G; A. A l l a r d ; 1967. The e f f e c t of hydrogen ion a c t i v i t y i n the s u l f i t e p u l p i n g of black spruce. Tappi 50 (12): 597-614. 72. J a s p e r , M. T. and P. Koch. 1975. Suspension burning of green bark to d i r e c t - f i r e high-temperature k i l n s f o r southern pine lumber. In Proc* of Wood Residue as Energy Source: FPRS Proc. no. P-75-13. pp. 70-72. 73. Karpushkina, A. A. and Yu. N. Tikhonov. 1969. K i n e t i c s of the s a p o n i f i c a t i o n of p o l y ( v i n y l cinnamate). Zh. F i z . Khim. 43(9): 2263-2264 (O r i g . not seen, c f ; CA 72: 131 80) . 74. Kaufmann, H. P. and M. C. K e l l e r ; 1937. S t u d i e s i n the f i e l d of f a t . XXXIV. The thermodynamics o f f a t - s p l i t t i n g . F e t t e u. S e i f e n 44: 105-107. 75. Keays, J . L. and J . V. Hatton. 1975. The i m p l i c a t i o n of f u l l - f o r e s t u t i l i z a t i o n on worldwide s u p p l i e s of wood by year 2000. Pulp Paper I n t . 17 (6): 49-52. 76. Kennedy, A. M. and J . M. J e r n i g a n . 1959. Process and apparatus f o r e l e c t r o l y t i c a l l y t r e a t i n g black l i g u o r . U.S. pat. 2,905,644 (Sept. 22, 1959). 77. K i e l l a n d , J . 1937. I n d i v i d u a l a c t i v i t y c o e f f i c i e n t s of i o n s i n agueous s o l u t i o n s . J . Am. Chem. Soc. 59(9): 1675-1678. 78. K o l t h o f f , I . M. and W. S t r i c k s . 1948. S o l u b i l i z a t i o n of dimethyl-aminobenzene i n s o l u t i o n s of detergents: I. The e f f e c t of temperature on the s o l u b i l i z a t i o n and upon the c r i t i c a l c o n c e n t r a t i o n . J . Phys. C o l l o i d Chem. 52: 9 15-941. 79. K r a t o h v i l , J. P. and H; T. D e l l i C o l l i . 1968. M i c e l l a r p r o p e r i t e s of b i l e s a l t s . Sodium taurodeoxycholate and sodium glycodeoxycholate. Can: J . Biochem; 46(8): 945-952. 80. K r i n g s t a d , K. 1978. The p r o d u c t i o n of chemicals from p u l p i n g waste. Tappi 61(1): 49. 81. K u l k a r n i , G; R. and W. J . Nolan. 1955. The mechanism of 111 a l k a l i n e p u l p i n g . Paper Industry 37(2): 142-151. 82. Kurth, E. F. and J. E. Smith. 1954. The chemical nature of the l i g n i n of D o u g l a s - f i r bark. Pulp Paper Mag; Can. 55(12): 125-133. 83. Landry, G. C. 1979. E f f i c i e n c y s t u d i e s improve recovery of byproducts at St; Regis m i l l s ; Pulp S Paper 53(2): 71-73. 84. Lange, W. and W. Schweers. 1980. The carboxymethylation of organosolv and k r a f t l i g n i n s . Wood S c i . Technol: 14: 1-7. 85. Langmuir, I . 1917. C o n s t i t u t i o n and fundamental p r o p e r t i e s of s o l i d s and l i g u i d s . I I . L i g u i d s . J . Am. Chem. Soc. 39: 1848-1906. 86. Larogue, G; L. and O. Maass. 1941. The mechanism of the a l k a l i n e d e l i g n i f i c a t i o n of wood. Can. J . Research 19B (1) : 1-16. 87. Lascaray, L. 1927. S a p o n i f i c a t i o n of f a t s i n a heterogeneous system. Anales soc. Espan. F i s . Quim. 25: 332-348 ( c f . CA 22: 175) . 88. Lascaray, L. 1937. S p l i t t i n g (fats) i n the autoclave with c a u s t i c a l k a l i e s . S e i f e n s i e d e r Ztg. 64: 122-124. 89. L a s c a r a y , L. 1949. Mechanism of f a t s p l i t t i n g ; Ind. Eng. Chem. 41 (4): 786-790. 90. Lascaray, L. 1952. I n d u s t r i a l f a t s p l i t t i n g . J . Am. O i l Chem. Soc. 29 (9): 362-366. 91. Law, K. N. and Z. Koran. 1979. U t i l i z a t i o n of white spruce f o l i a g e . Wood S c i . 12(2): 106-112. 92. Le d e r e r , E. L. 1930. K i n e t i c s of f a t s p l i t t i n g and f a t s a p o n i f i c a t i o n : Allgera; 0 1 - f e t t z t g . 27: 114-115 ( c f . CA 24: 4S46) . 93. Legg, G. W. and J . S. Hart. 1959. A l k a l i n e p u l p i n g of p o p l a r and b i r c h : The i n f l u e n c e of s u l f i d i t y and e f f e c t i v e a l k a l i on the r a t e of p u l p i n g and pulp p r o p e r t i e s . Pulp Paper Mag. Can; 60(7): T203-T215. 94. LeMon, S. and A. Teder. 1973. K i n e t i c s of the d e l i g n i f i c a t i o n i n k r a f t p u l p i n g . Svensk P a p p e r s t i d . 76 (1 1): 407-414. 95. Lenz, B. L. 1977. E f f e c t of hardwood black l i g u o r on t a l l o i l soap s e p a r a t i o n . Tappi 60(5): 121-123. 96. Lenz, B. L. and J . R. Mold; 1971. I o n - s e l e c t i v e e l e c t r o d e method compared to standard methods f o r sodium de t e r m i n a t i o n i n m i l l l i g u o r s . Tappi 54(12): 2051-2055. 112 97. L e v e n s p i e l , 0. 1972. In Chemical Reaction E n g i n e e r i n g . John Wiley and Sons, New York. pp. 360-374. 98. L u z a t t i , V., T a r d i e u , A., G u l i k - K r z y w i c k i , T., Rivas, E. and F. Reiss-Husson. 1968. S t r u c t u r e of the cubi c phases of l i p i d - w a t e r systems. Nature 220(5166): 485-488. 99. L u z i n a , L. I* 1966. The dependence of k r a f t pulp y i e l d on cooking c o n d i t i o n s . Bumazh. Prom. no. 8: 7-10 (c f . ABIPC 3 7: 5099). 100. McBain, J . W. 1942. S o l u b i l i z a t i o n and other f a c t o r s i n deterg e n t a c t i o n . In Advances i n C o l l o i d Science. V o l . 1. ed. Kraemer, E. C. , I n t e r s c i e n c e New York; pp. 99-142. 101. McBain, J . W. , Humphreys, C. W. and Y. Kawakami. 1929. Rate o f s a p o n i f i c a t i o n of v a r i o u s commercial o i l s , f a t s and waxes and pure t r i g l y c e r i d e s by agueous a l k a l i . J . Chem. Soc. 2185-2197 (cf. CA 24: 1999). 102. M a i s e l , D. S. 1978. I n d u s t r i a l o r g a n i c chemical feedstocks i n the f u t u r e . Tappi 61(1): 51-53. 103. Marton, J . 1971. Reactions i n a l k a l i n e p u l p i n g ; In L i g n i n s . ed. Sarkanen, K. V. and C. H. Ludwig, W i e l y - I n t e r s c i e n c e , New York; pp.670-671. 104. M i l l s , V. and H. K. McClain. 1949. Fat h y d r o l y s i s . Ind. Eng. Chem. 41 (9): 1982-1985. 105. M i t c h e l l , C. P.. and F* H. Yorston. 1934. The k i n e t i c s of a l k a l i n e p u l p i n g . Can. F o r e s t Prod. Lab. Quart. Rev. 18: 6-16. 106. Miyanami, K., Sato, M. and T. Yano. 1972. A p p l i c a b i l i t y of d i s p e r s i o n model to a packed bed r e a c t o r with an i r r e v e r s i b l e chemical r e a c t i o n of second-order. J . Chem. Eng. Japan 5(2): 156-160. 107. Moss, E. H. 1949. Natural pine hybrids i n A l b e r t a . Can. J. Pes. C27 (5) : 218-229. 108. M u e l l e r , H. H. and E. K. H o l t . 1948. Changes i n composition of the f a t phase during the T w i t c h w e l l s p l i t t i n g of coconut o i l . J . Am. O i l Chem; Soc; 25: 305-307. 109. Murray, F. E. 1959. The k i n e t i c s of o x i d a t i o n of k r a f t weak bla c k l i g u o r . Tappi 42 (9): 761-767. 110. Murray, F* E., Tench, L. G., A s f a r , J. J. and J . E. B u r k e l l . 1973. Oxidation of s u l f i d e s i n black l i g u o r u s i n g molecular oxygen. AICE Symp. Ser. 69(133): 102-105. 111. Myers, R. L. and R. L. M i l l e r . 1976. St. Regis h y d r o p y r o l y s i s process; In Forum on K r a f t Recovery 113 A l t e r n a t i v e s . I n s t , of Paper Chemistry* Appleton, Wis. pp. 74-102. 112. Nedashkovskii, A. N., S k y l a r , V. I. and N. A. O l e i n i k . 1978. Machine f o r s t r i p p i n g o f f t r e e f o l i a g e * Lesnoe Khoz v a i s t v o No.8: 63-64 ( O r i g . not seen* c f * FA 41:788). 113. Nelson, P. J . , Murphy, P. I. and F. C. James. 1977. Determination of the r e s i n content of wood from softwoods. Appita 30(6): 503-504. 114. Ono, T. 1939. H y d r o l y s i s of f a t and f a t a c i d e s t e r s I I . S a p o n i f i c a t i o n v e l o c i t y of f a t s and f a t a c i d e s t e r s . J . Agr. Chem. Soc* Japan 15: 953-965. 115. P a n n e t i e r , G* and P. Souchay. 1967. In Chemical K i n e t i c s ; E l s e v i e r , Barking, Engl. pp. 299-418. 116. Papp, J . 1973. P o t e n t i o m e t r i c determination of s u l f u r compounds i n white, green, and black [ p u l p i n g ] l i g u o r s with s u l f i d e - i o n s e l e c t i v e e l e c t r o d e . (2) D i r e c t p o t e n t i o m e t r i c determination of s u l f i d e c o n c e n t r a t i o n i n s u l f i d e and p o l y s u l f i d e s o l u t i o n s . C e l l ; Chem; Technol. 7 (6) : 733-740. 117. P a t e l , A. N. and P. I. I h e j i r i k a . 1978. K i n e t i c s of s a p o n i f i c a t i o n of palm seed o i l . T l u s z c z e , Srodki P i o r a c e , Kosmet. 22(8-9): 139-141. (Orig. not seen, c f . CA 90: 170496) 118. Pauly, G. and E. von R u d l o f f ; 1971. Chemosystematic s t u d i e s i n the genus Pinus: The l e a f o i l of Pinus c o n t o r t a v a r . l a t i f o l i a . Can. J . Botany 49: 1201-1209. 119. P e a r l , I . A. 1975. Agueous a l k a l i n e e x t r a c t i v e s of l o b l o l l y pine bark. Indian Pulp Paper 30(1): 11-12. 120. P e a r l , I . A. 1975. The e t h e r - s o l u b l e and e t h a n o l - s o l u b l e e x t r a c t i v e s of l o b l o l l y and s l a s h pine barks. Tappi 58(9): 135-137. 121. P e a r l , I . A., and E. E. Dickey. 1977. E f f e c t o f o x y g e n - a l k a l i p u l p i n g c o n d i t i o n s on the t a l l o i l components of southern pinewood. Tappi 60(10): 126-129. 122. Potapenko, A. P., Arestova, G; A; and L. A. Gerasimchuk. 1973. Study of main parameters of e l e c t r o d i a l y s i s of black l i g u o r on ion-exchange membranes. Zh. P r i k l . Khim. 46(3): 535-539 (Orig. not seen, c f ; ABIPC 45: 1646). 123. Prahacs, S. 1976. Some experiences at PPEIC i n development of chemical r e c o v e r y processes. In Forum on K r a f t Recovery A l t e r n a t i v e s . I n s t , of Paper Chemistry, Appleton, Wis. p. 226. 124. Preston, W. C. 1948. Some c o r r e l a t i n g p r i n c i p l e s of 114 d e t e r g e n t a c t i o n . J . Phys. C o l l o i d Chem. 52: 84-97. 125. Regnfors, L. and I. Stockman. 1956. How to d e f i n e a l k a l i n i t y and s u l p h i d i t y ? E f f e c t o f chemical/wood r a t i o on the k r a f t cook; Svensk P a p p e r s t i d . 59(14): 509-520. 126. Roberts, K., Ost e r l u n d , R. and C. Axberg. 1976. L i g u i d c r y s t a l s i n systems of r o s i n and f a t t y a c i d : i m p l i c a t i o n s f o r t a l l o i l recovery. Tappi 59(6): 156-159. 127. R o s a l e s , D. A. 1978. E v a l u a t i o n of lodgepole pine black l i g u o r e x t r a c t i o n (BLE) s o l i d r e s i d u e s as glue f i l l e r s i n p h e n o l i c glue mixes. Onpub. Report, Univ. Of B r i t i s h Columbia. 28 pp. 128. Rowe, J . W. , Ronald, R. C. and E. A. Nagasampagi. 1972. Terpenoids of lodgepole pine bark. Phytochem. 11(1): 365-369. 129. Rowe, J . W. and J . H. Scroggins. 1964. Benzene e x t r a c t i v e s of lodgepole pine bark: I s o l a t i o n of new d i t e r p e n e s . J . Org. Chem. 29 (6): 1554-1 562. 130. Rydholm, S. A. 1965. In Pulping Processes. I n t e r s c i e n c e , New York. pp. 583-589. 129. Rydholm, S. A. 1965. In Pul p i n g Processes: I n t e r s c i e n c e , New York. p. 764. 132. Saltsman, W. and K. A. Kuiken. 1959. E s t i m a t i o n of t a l l o i l i n s u l p h a t e black l i g u o r . Tappi 42 (1 1): 873-874. 133. Shrimpton, D. M. 1974. Composition of v o l a t i l e o i l from the bark of lodgepole pine. Bi-monthly Res. Notes, Can. F o r e s t r y Ser. 30(2): 12. 134. Smith, J . H. G. and A. Kozak. 1971. Thickness, moisture content, and s p e c i f i c g r a v i t y of i n n e r and outer bark of some P a c i f i c Northwest t r e e s : F o r e s t Prod. J . 21(2): 38-40. 135. Smith, L. E. 1932. K i n e t i c s of soap making. J . Soc. Chem. Ind. 51: 337-348T ( c f . CA 27: 202). 136. S p i t z , L. J . 1968. Advances i n s a p o n i f i c a t i o n , d r y i n g and s o a p - f i n i s h i n g technology. J. Am. O i l Chem. Soc. 45(6): 423-428. 137. S t e f a n a c , Z. and W. Simon. 1967. Highly s e l e c t i v e sodium io n r e sponsive g l a s s e l e c t r o d e . A n a l y t i c a l L e t t e r 1(2): 1-9. 138. S t e n g l e , W. B. 1971. Crude t a l l o i l manufacture: Part 2. Southern Pulp and Paper Manuf. 34(12): 26-31. 139. S t i r t o n , A. J . 1964. Soap and other s u r f a c e - a c t i v e agents. 115 In B a i l e y ' s I n d u s t r i a l O i l and Fat Products, ed. Swern, D., I n t e r s c i e n c e , New York. pp. 405-425. 140. S t i r t o n , A. J . 1964. Soapmaking; In B a i l e y ' s I n d u s t r i a l O i l and F a t Products, ed. Swern, D., I n t e r s c i e n c e , New York. pp. 977-978. 141. Stockman, L. and E. Sundkvist. 1958. Sulphate cooking at high temperatures. Svensk P a p p e r s t i d . 61(18B): 746-753. 142. Sturm, H. and J. F r e i . 1938. The r e a c t i o n e g u i l i b r i u m of f a t s p l i t t i n g : F e t t u. S e i f e n . 45: 219-223 ( c f . CA 32: 7755) . 143. Sturzenegger, A. and H. Sturm. 1951. H y d r o l y s i s of f a t s at high temperatures: Ind. Eng. Chem. 43(2): 510-515. 144. Suen, T . - j . and T.-p. Chien. 1941. Reaction mechanism of the a c i d h y d r o l y s i s of f a t t y a c i d s . Ind; Eng. Chem. 33 (8): 1043-1045. 145. Swartz, J . L. 1974. Continuous o n - l i n e measurment of e f f e c t i v e a l k a l i and s u l f i d i t y i n k r a f t b l a c k p u l p i n g l i g u o r s using i o n - s e l e c t i v e e l e c t r o d e s . Northeastern Univ. Ph.D. T h e s i s . 134 pp. 146. Swartz, J . L. and T. S. L i g h t . 1970. A n a l y s i s of a l k a l i n e p u l p i n g l i g u o r with s u l f i d e i o n - s e l e c t i v e e l e c t r o d e . Tappi 53 (1) : 90-95. 147. TAPPI. 1964. A n a l y s i s of soda and s u l f a t e black l i g u o r . T625 ts-64. 5 pp. 145. Tasman, J . E. 1980. K r a f t p u l p i n g behaviour of Canadian wood s p e c i e s . Pulp and Paper Hag. Can. 81(3): T19-T24. 149. T i m e l l , T. E. 1961. I s o l a t i o n o f p o l y s a c c h a r i d e s from the bark of Gymnosperms. Svensk P a p p e r s t i d ; 64(18): 651-661. 150. Tomlinson, G. H. and G. H. Tomlinson, J r . 1948. Method of t r e a t i n g l i g n o c e l l u l o s i c m a t e r i a l . Can. Pat. No. 448,476. 151. V a s s i e , J . E. 1953. The use of sulphur i n k r a f t pulp m i l l s . Tappi 36 (8): 367-368. 152. Vroom, K. E; 1957. The " H " - f a c t o r : A means of exp r e s s i n g cooking time and temperature as a s i n g l e v a r i a b l e . Pulp Paper Mag. Can. 58(C): 228-231. 153. Weigel, B. 1977. Conversion of a recovery b o i l e r to a r e f u s e - f i r i n g u n i t . Tappi 60(9): 89-93. 154. Weston, R. E. and H. A. Schwarz. 1972. In Chemical K i n e t i c s . P r e n t i c e - H a l l , Englewood C l i f f s , N. J . pp. 188-203. 116 155. Whalen, 0. M. 1975. Simple method f o r p r e c i p i t a t i n g e a s i l y f i l t r a b l e a c i d l i g n i n from k r a f t black l i g u o r . Tappi 58(5): 110-112. 156. Wilson, K. 1971. Determination of soap i n black l i g u o r . Svensk P a p p e r s t i d . 74(11): 352-356 ( c f . ABIPC T-903) . 157. W r i s t , P. E. 1976. O b j e c t i v e s of the forum. In Forum on K r a f t Recovery A l t e r n a t i v e s . I n s t , of Paper Chemistry, Appleton, Wis; pp. 11-14. 158. Y l l n e r , S., Ostberg, K. and I. Stockman. 1957. A study of the removal of the c o n s t i t u e n t s of pine wood i n the s u l p h a t e process using continuous l i q u o r flow method. Svensk P a p p e r s t i d ; 60 (21): 795-802. 159. Z i n k e l , D. F. 1975. T a l l o i l p r e c u r s o r s — a n i n t e g r a t e d a n a l y t i c a l scheme f o r pine e x t r a c t i v e s ; Tappi 58(1): 109-111. 160. Z i n k e l , D. F. 1975. T a l l o i l p r e c u r s o r s of l o b l o l l y p ine; Tappi 58 (2) : 118-121. T a b l e .1. P e t r o l e u m e t h e r e x t r a c t i o n o f l o d g e p o l e p i n e tree, p a r t s , e x p r e s s e d as p e r c e n t a g e o f o-d m a t e r i a l (n = 3 ) . M a t e r i a l B a r k T e c h n i c a l f o l i a g e Sapwood Hear twoo d Cones Pos i. t i o n T* M B C R C R Tl-M F r e e z e - d r y t (E) * 9 . 09 7.84 7 . 80 6 . 16 2 . 89 2.99 1.26 2.53 1 . 70 (W) 9 . 54 8.62 8 . 34 6.12 2 .97 2.60 1. 12 1.55 2.55 Ave . 9 . 3 2 8.23 8 . 07 6 . 14 2 . 9 3 2.80 1 . 19 2 . 04 2.13 (E) 9 . 01 7 . 39 7 . 27 5.81 2 . 74 2.33 1. 19 2.47 1.36 A i r - d r y (W) 9 . 54 8.04 7 . 90 5 . 89 2 .89 2.44 1.08 1.42 2.20 Ave . 9 . 28 7.72 7 . 59 5.85 2 . 82 2.39 1. 14 1.95 1 . 78 (E) 8 . 36 6.15 6 . 33 5.41 2 . 06 1. 76 1. 04 2.13 1.34 70°C Oven- (W) 9 . 06 6.95 6 . 7 1 5. 19 2 . 30 1.81 0.93 1.33 2.23 < 11: y Ave . a. 71 6.55 6 . 5 2 5.30 2 . 18 1.79 0 . 99 1.73 1.79 (E) 6 . 28 4.55 4 . 71 3 . 95 1 . 29 1.12 0 . 70 1. 13 1.10 .1.0 0°C Oven- (W) 6 . 6 9 4.98 4 . 84 3.79 1 . 3 3 1.21 0.68 0 . 79 1 . 76 d r y Ave . 6 . 4 9 4 . 77 A . 78 3.87 1 . 3 1 1.17 0 . 69 0 . 96 1.43 * ( B ) o t t o m o f crown; (C ) r o w n b a s e ; ( E ) a s t t r e e ; ( M ) i d d l e b ( R ) e a s t h e i g h t ; ( T ) o p o f crown; ( W ) e s t t r e e . i F r e e z e - d r y i n g was f o l l o w i n g l i q u i d n i t r o g e n f r e e z i n g . o f crown; 118 Table 2. A n a l y s i s of v a r i a n c e f o r petroleum ether e x t r a c t i o n of lodgepole pine bark* Source of v a r i a t i o n DF Mean sguare Test term F S i g n i f i c a n c e Drying treatments 3 14.48 538.98 ** Trees 1 6.30 234.67 ** Tr e a t , x Tree 3 0.46 17.11 ** E r r o r 16 0.03 T o t a l 23 Duncan's m u l t i p l e range t e s t , l e v e l of s i g n i f i c a n c e = 0.01 Treatments Freeze-dry A i r - d r y 70<>C Oven 100°C Oven Fre g u e n c i e s 6 6 6 6 Means 9.80 9.76 8.71 6.49 Means u n d e r l i n e d by the same l i n e are not s i g n i f i c a n t l y d i f f e r e n t . ** i n d i c a t e s s i g n i f i c a n c e at 0.01 l e v e l . N.S. i n d i c a t e s not s i g n i f i c a n t . 119 Table 3. A n a l y s i s of v a r i a n c e f o r petroleum ether e x t r a c t i o n of lod g e p o l e pine t e c h n i c a l f o l i a g e . Source of v a r i a t i o n DF Mean sguare Test term F S i g n i f i c a n c e Drying treatments 3 31.91 2546.0 ** Trees 1 2.03 . Posn./tree 0.22 N. S Treat, x Tree 4 0.09 7. 39 ** P o s i t i o n / T r e e 3 9.29 740. 98 ** T r e a t , x Posn. 12 0. 28 22.04 ** E r r o r 48 0. 012 T o t a l 71 Duncan's m u l t i p l e range t e s t , l e v e l of s i g n i f i c a n c e = 0.01 Treatments Freeze-dry A i r - d r y 70<>C Oven 100°C Oven Fre q u e n c i e s 18 18 18 18 Means 7.47 7.05 6.12 4.47 Any two means d i f f e r s i g n i f i c a n t l y . P o s i t i o n s / T r e e T/E M/E B/E B/W T/W M/W Frequencies 12 12 12 12 12 12 Means 6.48 6.53 5.33 5.25 7.15 6.95 Means u n d e r l i n e d by the same l i n e are not s i g n i f i c a n t l y d i f f e r e n t . ** i n d i c a t e s s i g n i f i c a n c e at 0.01 l e v e l . N.S. i n d i c a t e s not s i g n i f i c a n t . 120 Table 4. A n a l y s i s of v a r i a n c e f o r petroleum ether e x t r a c t i o n of lodgepole pine sapwood* Source of v a r i a t i o n DF Mean sguare Test term F S i g n i f i c a n c e Drying treatments 3 5. 65 1155.0 ** Trees 1 0. 12 Posn./tree 0.19 N.S. Tr e a t , x Tree 3 0. 002 0.37 N.S. P o s i t i on/Tree 2 0. 63 129.25 ** Treat, x Posn. 6 0. 025 5. 12 ** E r r o r 32 0. 005 T o t a l 47 Duncan's m u l t i p l e range t e s t , l e v e l of s i g n i f i c a n c e = 0.01 Treatments Freeze-dry A i r - d r y 70°C Oven 100<>C Oven Fr e q u e n c i e s 12 12 12 12 Means 2.76 2.60 1.96 1.23 Any two means d i f f e r s i g n i f i c a n t l y . P o s i t i o n s / T r e e C/E R/E C/W R/W Fregu e n c i e s 12 12 12 12 Means 2.24 1.93 2.34 2.02 Any two means d i f f e r s i g n i f i c a n t l y . ** i n d i c a t e s s i g n i f i c a n c e at 0.0 1 l e v e l * N.S. i n d i c a t e s not s i g n i f i c a n t . C—wood from the base of tre e (C)rown. R--wood from b ( R ) e s t - h e i g h t . 121 Table 5. A n a l y s i s of v a r i a n c e f o r petroleum ether e x t r a c t i o n of lodg e p o l e pine heartwood* Source of v a r i a t i o n DF Mean sguare Test term F S i g n i f i c a n c e Drying treatments 3 1.53 404.05 ** Trees 1 2.37 Posn./tree 0.69 N.S. T r e a t , x Tree 3 0.10 27.32 ** P o s i t i o n s / T r e e 2 3.43 908.04 ** Treat, x Posn. 6 0.14 37.12 ** E r r o r 32 0.004 T o t a l 47 Duncan's m u l t i p l e range t e s t , l e v e l of s i g n i f i c a n c e = 0.01 Treatments Freeze-dry A i r - d r y 70<>C Oven 100°C Oven Freq u e n c i e s 12 12 12 12 Means 1.62 1.54 1.36 0.83 Any two means d i f f e r s i g n i f i c a n t l y . P o s i t i o n s / T r e e C/E R/E C/W R/W Frequencies 12 12 12 12 Means 1.05 2.06 0.95 1.27 Any two means d i f f e r s i g n i f i c a n t l y . ** i n d i c a t e s s i g n i f i c a n c e at 0.01 l e v e l * N.S. i n d i c a t e s not s i g n i f i c a n t . C—wood from the base of t r e e (C) rown. R—wood from b (P.) e s t - h e i g h t . 122 T a b l e 6. A n a l y s i s of v a r i a n c e f o r p e t r o l e u m e t h e r e x t r a c t i o n o f l o d g e p o l e p i n e c o n e s . S o u r c e o f v a r i a t i o n DF Mean s q u a r e T e s t t e r m F S i g n i f i c a n c e D r y i n g t r e a t m e n t s 3 0.49 85.91 ** T r e e s 1 3.99 705.37 ** T r e a t , x T r e e 3 0.016 2.82 N.S. E r r o r 16 0.006 T o t a l 23 Duncan's m u l t i p l e r a n g e t e s t , l e v e l o f s i g n i f i c a n c e = 0.01 T r e a t m e n t s F r e e z e - d r y A i r - d r y 70OC-Oven 100°C Oven F r e g u e n c i e s 6 6 6 6 Means 2.12 1.78 1.78 1.43 Means u n d e r l i n e d by t h e same l i n e a r e n o t s i g n i f i c a n t l y d i f f e r e n t . ** i n d i c a t e s s i g n i f i c a n c e a t 0.01 l e v e l . N.S. i n d i c a t e s n o t s i g n i f i c a n t . 123 Table 7* Sieve a n a l y s e s of BLE lodgepole pine m a t e r i a l s as percentage of sample r e t a i n e d on screen. I Mesh | Bark | T e c h n i c a l F o l i a g e |Sapwood|Heartwood| S i z e | | Coarse Medium Fine | Coarse Medium Fi n e | Fine | Fine 10 26. 5 0. 7 12.1 20 46. 2 46. 4 19.7 78.1 35.9 16.3 21. 1 20. 3 35 — — 42.6 6. 4 33* 1 40. 8 38.4 39.8 50 20. 6 40.6 18.1 1.8 16.1 23. 2 23.6 24. 2 80 -- — 9.9 — — 10* 8 10: 5 9.1 100 4.7 8.3 2.4 0.9 8.2 1.7 4.0 4.7 >100 2.0 4.0 7.3 0.7 6.7 7.3 2.4 1.9 1 2 4 Table 8* BLE cooking schemes: | Cook Sequence May 1 7 8 | J u l •7 8|Sep « 7 8 | May ' 7 9 Jun • 7 9 | I Temperature °C 1 0 0 | 1 7 0 | 1 2 0 | 1 4 5 8 0 | | Bomb No.| Sample | Liq u o r At Temperature Time , hr; I 1 I B 1 N 4 | 1 | 2 I 1 . 5 1 2 | I 2 I B 2 N 4 | 1 | 2 I 1 . 5 12 | I 3 I B 3 N 4 | 1 | 2 | 1 . 5 1 2 | I 4 I B 1 R 4 | 1 | 2 I 1 . 5 1 2 | I 5 I B 2 R 4 I 1 I 2 I 1 . 5 1 2 | I 6 I B 3 R 4 I 1 I 2 I 1 . 5 1 2 | I 7 I E 1 N I 4 | 1 | 2 I 1 . 5 1 2 | I 8 I P 2 I N 4 | 1 | 2 I 1 . 5 1 2 | I 9 | F 3 N 4 | 1 | 2 I 1 . 5 1 2 | | 10 | F 1 R 4 I 1 | 2 I 1 . 5 1 2 | | 11 I F 2 R 4 | 1 | 2 I 1 : 5 1 2 | I 1 2 I F 3 R I 4 I 1 I 2 I 1 . 5 1 2 | I 1 3 | S 3 N 4 | 1 | 2 I * * I | 14 I s 3 R 4 I 1 | 2 I * * I I 1 5 I H 3 N 4 | 1 | 2 I * * I I 16 | H 3 R I 4 | 1 | 2 I * * I I S a t e l l i t e D i g e s t e r s I | 17 I B 3 ! R I 0 . 5 | 0 . 2 5 I 0 . 2 5 | 0 . 1 8 7 1 . 5 | | 18 I F 3 ! R | 0 . 5 | 0 . 2 5 | 0 . 2 5 | 0 . 1 8 7 1 . 5 | | 19 I B 3 R | 1 | 0 . 5 | 0 . 5 | 0 . 3 7 5 3 I I 2 0 I F 3 R | 1 | 0 . 5 | 0 . 5 | 0 . 3 7 5 3 I | 21 I B 3 ! R I 2 | 0 . 7 5 | 1 I 0 . 7 5 6 | | 2 2 I F 3 i R | 2 | 0 . 7 5 | 1 I 0 . 7 5 6 I * i n s t e a d of wood meals, bark and t e c h n i c a l f o l i a g e medium f r a c t i o n s were cooked with sodium hydroxide s o l u t i o n of comparable s t r e n g t h s t o the black l i g u o r s employed. B = bark F = t e c h n i c a l f o l i a g e N = o r i g i n a l black l i q u o r R = N l i q u o r plus 5 g/1 NaOH 1 = coarse f r a c t i o n 2= medium f r a c t i o n 3= f i n e f r a c t i o n T a b l e 9. M o d i f i e d H - f a c t o r c a l c u l a t e d from t h e A r r h e n i u s e g u a t i o n f o r BLE l o d g e p o l e p i n e b a r k and t e c h n i c a l f o l i a g e . M a t e r i a 1 Bark T e c h n i c a l F o l i a g e A c t i v a t i o n E n e r g y 9671 c a l / m o l e 8814 c a l / m o l e T e m p e r a t u r e OC H' - F a c t o r 60 1 1 65 1.24 1.22 70 1.53 1. 47 75 1.88 1.78 80 2.30 2. 13 85 2.79 2. 54 90 3.37 3.01 95 4.04 3. 55 1 00 4.83 4. 18 105 5.75 4. 89 1 10 6.81 5. 70 115 8.02 6.61 120 9.42 7.65 125 11.01 8. 82 130 12.83 10. 12 135 14.89 1 1. 59 140 17.21 13. 22 1 45 19.83 15.03 150 22.76 17. 04 155 26.07 19. 26 160 29.75 21.71 165 33.84 24.41 170 38.39 27.37 126 Table 10. C a l i b r a t i o n of pH and sodium i o n s e l e c t i v e e l e c t r o d e po-t e n t i a l s i n standard sodium hydroxide s o l u t i o n s at 25<>C. Sodium C (Na) Y (Na) A (Na) E(o) E ( j ) * E(c) (M/l) (M/l) (mv) (mv) (mv) 1.019 0. 697 0.710 156.6 18.6 138.0 0. 100 0.775 0.078 90.4 3.7 86.7 0.010. 0.902 . 0090 33. 1 -3.1 36.2 .0010 0. 964 .00096 -22.0 -6.8 -15.2 +1.128 0.697 0.786 C a l i b r a t i o n Eguation: logA(Na) = -2. 729 + 0. 0187 E '(c) , ( r 2 = . 998) Hydroxide C (OH) Y (OH) A (OH) E(o) E(j) * E (Na) E(c) (M/l) (M/l) (mv) (mv) (mv) (mv) 1. 019 0. 661 0.674 -363.5 18.5 4.6 -386.6 0. 100 0. 761 0.076 -326.5 3.7 0.0 -330.2 0. 010 0.900 .0090 -275.8 -3. 1 0.0 -272.7 .0010 0. 964 .00096 -210.7 -6.8 0.0 -203.9 +0.100 0. 760 0.076 -315.5 4.6** -320.1 C a l i b r a t i o n Eguation: logA (OH) = -6. 243 - 0.0156 E ( c ) , ( r 2 = . 999) C = molal c o n c e n t r a t i o n of the i o n i c s p e c i e s . Y = the ion a c t i v i t y c o e f f i c i e n t at the c o n c e n t r a t i o n range ( c f . K i e l l a n d and Bates et a l . ) . A = the a c t i v i t y of the i o n . E(o) = observed p o t e n t i a l . E(j) = t h e - l i g u i d j u n c t i o n p o t e n t i a l . E (Na) = the sodium e r r o r p o t e n t i a l . E (c) = the c o r r e c t e d p o t e n t i a l . * i n c a l c u l a t i n g the l i g u i d j u n c t i o n p o t e n t i a l , r e f e r e n c e e l e c t r o d e f i l l i n g s o l u t i o n was taken as the primary s o l u t i o n . Thus, the p o l a r i t y of adjustments with r e s p e c t to measured p o t e n t i a l were a c t u a l l y r e v e r s e d . + data of the standard s o l u t i o n f o r sodium e r r o r c a l c u l a t i o n , which c o n s i s t e d of 1 mole of NaCl and 0.1 mole of NaOH. ** only by co i n c i d e n c e that t h i s value i s the same as sodium e r r o r c o r r e c t i o n f o r 1.0 M standard s o l u t i o n . 127 F i g 1. BLE cooking schemes as time-temperature p r o f i l e s . T r a n s c r i b e d from the F o r i n t e k automatic temperature r e g i s t e r c h a r t s . Arrows i n d i c a t e t e r m i n a t i o n p o i n t s of the time s e r i e s cooks. 128 F i g 2. Diagram of the manual press f i l t e r used i n s e p a r a t i n g b l a c k l i g u o r s from s o l i d r e s i d u e s . 129 F i g 3. Schematic diagram of BLE d i r e c t p o t e n t i o m e t r i c m o n i t o r i n g . N 2 Hot water from K 1 L D To pH meters •To c o n d e n s e r c u L ."V •'.•t-.'^-'.-i ( I ) A Return to K • B A. Magnetic s t i r r e r B. E x t e r n a l water bath C. Reaction v e s s e l D. Temperature probe E. Sodium ion e l e c t r o d e F. Reference e l e c t r o d e G. pH e l e c t r o d e H. Gas i n l e t I . Gas o u t l e t J . Srubber K. Haake FK 2 water bath with temperature c o n t r o l L. Black l i g u o r S. Sample m a t e r i a l 130 F i g 4. S o l i d r e s i d u e (SR) y i e l d s vs: cooking times f o l l o w i n g b l a c k l i g u o r e x t r a c t i o n of l o d g e p o l e pine bark and t e c h n i c a l f o l i a g e ; Time s c a l e i s the r e l a t i v e legnth of cooking p e r i o d f o r a p a r t i c u l a r temperatures-time s e r i e s . 20i 1 8 1 16H 14 cr c o 1 2 10 ® Bark A Foliage T 8 0 1 0 0 1 2 0 1 4 5 1 4 5 r1.0 -0.9 H0.8 ±0.7 -0.6 O Cv) \ DC 00 1 7 0 O h0.5 1-0.4 0.3 .125 .25 0.5 Relative Cooking Time " i — .75 131 F i g 5. S o l i d r e s i d u e (SR) y i e l d s as f i r s t order p l o t s with r e s p e c t to cooking times f o l l o w i n g black l i g u o r e x t r a c t i o n of lodgepole pine bark and t e c h n i c a l f o l i a g e . A 20-g b a s i s per sample i s assumed f o r the i n i t i a l SR. Regression l i n e s are extended to b e t t e r show the s l o p e s and are not intended as e x t r a p o l a t i o n s . 1st order o — B a r k - Foliage o CM \ OC CO -0-8H Cooking Time (Hr.) 132 F i g 6. S o l i d r e s i d u e (SR) y i e l d s as second order p l o t s with r e s p e c t to cooking times f o l l o w i n g black l i g u o r e x t r a c t i o n of lodgepole pine bark and t e c h n i c a l f o l i a g e . A 20-g b a s i s per sample i s assumed f o r the i n i t i a l SR. . Regression l i n e s are extended to b e t t e r show the s l o p e s and are not intended as e x t r a p o l a t i o n s . 133 F i g 7. A r r h e n i u s p l o t f o r determining lodgepole pine bark (Yb) and t e c h n i c a l f o l i a g e (Yf) BLE apparent e n e r g i e s of a c t i v a t i o n . S u b s c r i p t numbers are r e a c t i o n o r d e r s . 1 l c ~3A Bark o 1st order o 2nd order Fol iage a 1st order • 2nd order o a 27 22 23 24 25 26 1 / T X 1 0 5 28 29 134 F i g 8. BLE e m p i r i c a l f u n c t i o n s i n r e l a t i o n to lodgepole pine bark (Yb) and t e c h n i c a l f o l i a g e (Yf) s o l i d r e s i d u e (SR) data. A 20-g weight b a s i s per sample f o r SR i s assumed. 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1-8 Log (t1H'+t2aH') 135 F i g 9. BLE e m p i r i c a l f u n c t i o n s i n r e l a t i o n to lodgepole pine bark and t e c h n i c a l f o l i a g e r e c i p r o c a l s o l i d r e s i d u e (SR) data. A 20-g weight b a s i s per sample f o r SR i s assumed. 136 F i g 10. C o r r e l a t i o n between lodgepole pine bark BLE t o t a l crude t a l l o i l (TTO) and s o l i d r e s i d u e (SR). Both v a r i a b l e s are expressed as percentages of o r i g i n a l sample 0-D weights. TTO data are c o r r e c t e d f o r i n i t i a l t a l l o i l contents of black l i q u o r s (N i s the o r i g i n a l l i g u o r ; and R i s the o r i g i n a l r e i n f o r c e d with 5 g/1 sodium hydroxide). 10n 1 r j— 20 30 40 50 Solid Residue (%) 137 F i g 11. C o r r e l a t i o n between lodgepole pine t e c h n i c a l f o l i a g e BLE t o t a l crude t a l l o i l (TTO) and s o l i d r e s i d u e (SR). Both v a r i a b l e s a r e expressed as percentages of o r i g i n a l sample 0-D weights. TTO data are c o r r e c t e d f o r i n i t i a l t a l l o i l contents of black l i g u o r (N i s the o r i g i n a l l i g u o r ; and R i s the o r i g i n a l r e i n f o r c e d with 5 g/1 . sodium h y d r o x i d e ) . 7 T ® 6H • Liquor N 9 Liquor R o Time series @ R/ Time series All foliage R liquor N liquor CD •D o 5H —8— 30 40 ~50 60 S o l i d R e s i d u e (%) 138 F i g 12. P o t e n t i o m e t r i c t i t r a t i o n of the black l i g u o r a c t i v e a l k a l i . 139 F i g 13. A r g e n t i m e t r i c t i t r a t i o n f o r black l i g u o r sodium s u l f i d e d e t e r m i n a t i o n s (A i s u n o x i d i z e d black l i g u o r with b u f f e r ; B i s o x i d i z e d black l i g u o r without b u f f e r ; and C i s o x i d i z e d black l i g u o r with b u f f e r . ) Sulfide C o n e ( M / L ) 0 . 0 2 5 . 0 5 0 - 0 7 5 0 . 1 . 1 2 5 i 1 1 — . 1 1 1— 0 5 I O 15 2 0 2 5 V O L . (ml) 140 F i g 14. 1.0-1 C a l i b r a t i o n curve f o r d i r e c t potentiometry of sodium i o n s e l e c t i v e e l e c t r o d e : C i r c l e s denote the observed p o t e n t i a l s and dots are the c o r r e c t e d p o t e n t i a l s (adjusted f o r l i g u i d - j u n c t i o n p o t e n t i a l s ) . 0.1 CD J5 o > £0.01-o o co .ooH -20 20 40 60 80" 100 E N a (M i l l i vo l t ) "l2o" "l40* 160 14 1 F i g 15. 1 . C H C a l i b r a t i o n curve f o r d i r e c t potentiometry of hydroxide i o n . C i r c l e s denote the observed p o t e n t i a l s and dots are the c o r r e c t e d p o t e n t i a l s (adjusted f o r sodium e r r o r and l i g u i d - j u n c t i o n p o t e n t i a l s ) . ~ 0 . 1 -CD •4—> • ro o -»—> > o < CD 10 - 0 1 -o v_ "a >, X . 0 0 1 -- 4 0 0 - 3 6 0 - 3 2 0 - 2 8 0 E Q H (Mil l ivolt) — n r - 2 4 0 2 0 0 142 F i g 16. D i r e c t p o t e n t i o m e t r i c monitoring of BLE of lodgepole pine bark, t e c h n i c a l f o l i a g e and sapwood samples at 143 Appendix 1. Scanning electronmicrographs of lodgepole pine bark samples. 144 Appendix 2. P e t r o l e u m e t h e r e x t r a c t i o n o f l o d g e p o l e p i n e t r e e p a r t s ( d a t a from f l a s k w e i g h t g a i n e x p r e s s e d a s p e r c e n t 0-D m a t e r i a l w e i g h t , . n_ = 3). I . EAR K T r e a t m e n t Tree--E Tree-W F r e e z e - d r i e d 9. 06 9.00 9. 07 10. 30 10.92 10.40 A i r - d r i e d 8.94 8. 98 9. 10 10.51 10.74 10.30 70OC Oven 8.32 8. 42 8. 33 9.07 9.12 8.98 100oc Oven 6. 18 6. 32 6.34 6. 75 6.84 6.49 I I . TECHNICAL FOLIAGE T r e e E T r e a t m e n t Top M i d d l e Bottom F r e e z e - d r i e d 7. 71 7.84 7. 96 7.74 7.58 8 . 07 6.18 6.18 6. 12 A i r - d r i e d 7. 51 7. 36 7. 31 7.24 7.38 7 . 19 5.68 5. 90 5. 85 70oc Oven 6. 16 6. 07 6. 21 6.25 6.33 6 . 40 5.36 6.07 6. 21 100oo c oven 4. 49 4.62 4. 55 4.83 4.57 4 . 72 3.92 3.88 4. 06 T r e e W T r e a t m e n t Top M i d d l e Bottom F r e e z e - d r i e d 8. 58 8.74 8.53 8.41 8.38 8 .22 6.27 6.10 5. 98 A i r d r i e d 7. 97 8. 06 8.10 7. 79 7.94 7 . 98 5. 95 5. 80 5. 93 70<>c Oven 7. 07 6.87 6.91 6.89 6.66 6 . 59 5.32 5.06 5. 20 100°c Oven 5. 09 4. 87 5. 02 4. 75 4.93 4 . 84 3.80 3.87 3. 71 I I I . HEARTWOOD Tree E Crown Base Treatment Breast-Height F r e e z e - d r i e d A i r - d r i e d 70<>c Oven 100OC Oven 1.26 1.24 1.27 1.20 1.17 1.21 1.09 1.03 0.99 0.72 0.68 0.71 1.51 2.54. 2.55 2.44 2.57 2.41 2. 13 2.06 2.21 1.12 1.17 1.09 Tree W Crown Base Treatment Breast-Height F r e e z e - d r i e d A i r - d r i e d 70OC Oven 100QC Oven 1.07 1.14 1.15 1.08 1.02 1.13 0.96 0.93 0.89 0.64 0.77 0.63 1.40 1.61 1.65 1.41 1.38 1.46 1.25 1.32 1.44 0.64 0.76 0.81 IV SAPWOOD Tree E Crown Base Treatment Breast-Height F r e e z e - d r i e d A i r - d r i e d 70«c Oven 100OC Oven 2.89 2.84 2.93 2.84 2.61 2.76 1.95 2.14 2.08 1.33 1.28 1.25 2.39 2.54 2.53 2.26 2.41 2.33 1.85 1.79 1.64 1.09 1.12 1.15 Tree W Crown Base Treatment Breast-Height F r e e z e - d r i e d A i r - d r i e d 70oc Oven 100QC Oven 3.01 2.92 2.98 2.82 2.94 2.90 2.20 2.24 2.17 1.27 1.35 1.38 2.65 2.49 2.66 2.51 2.40 2.42 1.82 1.84 1.76 1.20 1.18 1.26 V PINE CONES T r e a t m e n t T r e e E T r e e W F r e e z e - d r i e d 1.66 1.72 1.71 2.55 2.48 2.63 A i r - d r i e d 1.46 1.26 1.35 2.23 2.24 2.14 70»c Oven 1.44 1.21 1.36 2.25 2.29 2.15 100OC Oven 1.14 1.08 1.07 1.68 1.82 1.78 T r e a t m e n t means a r e summarized i n T a b l e 1. 147 Appendix 3. Black l i g u o r e x t r a c t i o n r e s u l t s of lo d g e p o l e pine t r e e p a r t s (30-g 0-D m a t e r i a l ; 200-ml l i g u o r ) . I. BAR K T t H L SR 1F A1T 2F A2T 1 FT 2FT TTO 80 12 B1 N 16. 25 167 38. 54 254 32. 69 1287: 2 830. 3 2117. 5 80 12 B2 N 15. 81 168 41. 70 219 33. 44 1401. 1 732. 3 2133. 4 80 12 B3 N 15. 04 171 42. 81 23 1 34. 97 1464. 1 807. 8 2271. 9 80 12 B1 R 14. 26 190 42. 15 250 26. 24 1601. 7 677. 0 2278. 7 80 12 B2 R 13. 51 186 48. 45 246 20. 68 1801. 6 508. 7 2310. 3 80 12 B3 R 12. 36 172 56. 47 238 21. 38 19 53. 2 508. 8 2462. 0 80 6 B3 R 13. 54 190 45. 80 204 30. 54 1740. 4 623. 0 2363. 4 80 3 B3 R 14. 73 193 41. 76 263 24. 12 1611. 9 634; 4 2246. 3 80 1.5 B3 R 15. 76 176 40. 10 216 34. 79 1411. 5 751. 4 2162. 9 100 4 B1 N 14. 79 159 35. 70 258 45. 97 1135. 3 1186. 0 2231. 3 100 4 B2 N 14. 15 144 37. 20 334 39. 57 1071. 4 1321. 5 2283. 9 100 4 B3 N 14. 87 130 34. 30 172 78. 70 891. 8 1353. 6 2245. 4 100 4 B1 R 12. 79 160 52. 46 264 32. 79 16 78. 7 865; 7 2544. 4 100 4 B2 R 12. 05 150 53. 07 261 38. 76 1592. 1 1011. 6 2603. 7 100 4 B3 R 11. 68 133 49. 99 262 51. 14 1329. 7 1339; 9 2669. 6 100 2 B3 R 13. 85 131 37. 93 230 59. 17 9 93. 8 1360; 9 2354. 7 100 1 B3 R 14. 38 126 35. 94 232 66. 63 905. 7 1545. 8 2451. 5 100 0.5 B3 R 15. 20 125 40. 46 317 41. 95 1011. 5 1329. 8 2341. 3 120 2 B1 N 11. 65 154 40. 35 236 46. 95 12 42. 8 1108. 0 2350. 8 120 2 B2 N 11. 47 147 42. 70 257 43. 91 1255. 4 1128. 5 2383. 9 120 2 B3 N 11. 26 133 46. 74 226 51. 30 12 43. 3 1 159; 4 2402. 7 120 2 B1 R 9. 27 168 53. 13 240 35. 83 1785. 2 872. 0 2657.2 120 2 B2 R 10. 38 152 52. 98 220 48. 55 1610. 6 1068. 1 2678. 7 120 2 B3 R 9. 69 162 51. 60 166 44. 74 1995. 8 742: 7 2738. 5 120 1 B3 R 10. 75 155 53. 11 255 38. 52 1646. 4 1982. 2 2628. 6 120 0. 5 B3 R 11. 12 159 54. 50 275 27. 87 1733. 1 766. 4 2499. 5 120 0. 25 B3 R 11. 91 151 50. 05 291 32. 34 1511. 5 941; 1 2452. 6 145 1.5 B1 N 9. 39 162 46. 66 260 37. 06 1511. 8 977. 6 2489. 4 145 1.5 B2 N 9. 69 160 46. 86 290 33. 79 1499. 5 979. 9 2479. 4 145 1.5 B3 N 9. 95 163 42. 15 224 47. 84 1374. 1 1071; 6 2445. 7 145 1.5 B1 R 7. 57 183 55. 97 200 33. 98 2048. 5 679. 6 2728. 1 145 1.5 B2 R 7. 83 184 52. 57 194 38. 44 1934. 6 745. 7 2680. 3 145 1.5 B3 R 7. 98 182 60. 00 249 26. 93 21 84. 0 670: 6 2854. 6 145 0. 75 B3 R 8. 64 176 53. 58 269 28. 57 18 86. 0 768. 5 2654. 5 145 .375 B3 R 9. 08 227* 43. 31 20 0 28. 84 1966. 3 768. 0 2734. 3 145 . 187 B3 R 9. 48 147 49. 96 268 38. 88 1468. 8 1042. 0 2510. 8 (Continue next page) 148 I. BARK (Continue) T t M L SR 1F A1T 2F A2T 1 FT 2FT TTO 170 ! B1 N 9. 18 152 38.32 203 35.55 1164. 9 1443. 3 2608. 2 170 1 B2 N 9. 27 148 37. 16 245 31.97 1100. 0 1566. 5 2666. 5 170 1 B3 N 8. 66 163 46.33 250 25.02 1510. 4 12 50; 0 2760. 4 170 1 B1 R 8. 78 159 47.21 285 20.82 1501. 3 1186. 7 2688. 0 170 1 B2 R 8. 55 150 44. 60 225 30.78 1338. 0 1385. 1 2723. 1 170 1 B3 R 7. 23 160 56.60 265 22. 12 1811. 2 1 172. 4 2983. 6 170 0.75 B3 R 7. 30 161 62. 41 252 18.03 2009. 6 908. 7 2918. 3 170 0. 5 B3 R 7. 45 170 58. 19 278 19.94 1978. 5 1108. 7 3087. 2 170 0. 25 B3 R 7. 61 163 55.27 287 19.71 1801. 8 1131. 4 2933. 2 II* TECHNICAL FOLIAGE T t M L SR 1F A1T 2F A2T 1 FT 2FT TTO 80 12 F1 N 17. 80 182 26. 15 190 16.36 951. 9 310. 8 1262. 7 80 12 F2 N 16. 04 188 19.77 184 18.30 1 1 19. 4 336. 7 1456. 1 80 12 F3 N 15. 11 186 32.43 216 13.52 1206. 4 292. 0 1498. 4 80 12 F1 R 15. 92 194 29.81 267 9.94 1156. 6 265; 4 1422. 0 80 12 F2 R 14. 07 192 35.96 202 9. 17 1380. 9 185. 2 1566. 1 80 12 F3 R 13. 45 194 35.62 177 17.98 1382. 1 318. 2 1700. 3 80 6 F3 R 14. 70 196 33. 19 261 9.42 1301 . 0 245: 9 1546. 9 80 3 F3 R 15. 38 186 30.87 245 12.61 1148. 4 308. 9 1457. 3 80 1.5 F3 R 15. 92 219* 25.20 152 18.44 1103. 8 280. 3 1384. 1 100 4 F1 N 16. 26 162 33. 18 288 13. 90 1075. 0 • 400. 3 1475. 3 100 4 F2 N 14. 95 154 37.04 31 1 13. 16 1140. 8 409. 3 1550. 0 100 4 F3 N 14. 17 162 33.45 236 18.72 10 83. 8 441. 8 1525. 6 100 4 F1 R 14. 73 163 34.48 315 12.09 1124. 0 380; 8 1504. 8 100 4 F2 R 13. 40 160 35.31 262 24.38 1129. 9 638. 8 1768. 7 100 4 F3 R 12. 87 170 33.53 308 23.13 1140. 0 712. 4 1852. 4 100 2 F3 R 13. 59 168 36.60 338 17.38 1229. 8 587. 8 1817. 6 100 1 F3 R 14. 83 180 28.93 322 21.60 1041. 5 695. 5 1737. 0 100 0.5 F3 R 14. 91 179 25.87 281 22.91 890. 3 643. 8 1534. 1 Continue next page 149 I I ; TECHNICAL FOLIAGE (Continue) T t M L SR 1F A1T 2F A2T 1 FT 2FT TTO 120 2 F1 N 14. 40 164 33. 34 196 19. 28 1115. 2 377. 9 1493. 1 120 2 F2 N 13. 03 170 37. 10 238 14. 29 1261. 4 340. 1 1601. 5 120 2 F3 N 12. 36 165 37. 83 189 22. 66 1248. 4 428. 3 1676. 7 120 2 F1 R 12. 36 168 32. 86 196 24. 34 1104. 1 477. 1 1581. 2 120 2 F2 R 1 1 . 50 170 38. 41 268 14. 12 1305. 9 378. 4 1684. 3 120 2 F3 R 11. 20 176 39. 95 230 17. 30 1406. 2 397. 9 1804. 1 120 1 F3 E 11. 72 175 40. 32 30 1 11. 48 1411. 2 345. 5 1756. 7 120 0. 5 F3 E 12. 06 212* 33. 52 216 15. 27 1421. 3 329. 8 1751. 1 120 0. 25 F3 R 12. 75 177 36. 49 260 16. 91 1291. 7 439. 7 1731. 4 145 1.5 F1 N 10. 42 190 32. 18 248 21. 22 12 22. 8 526. 3 1749. 1 145 1.5 F2 N 10. 93 177 35. 24 219 22. 20 1247. 5 486. 2 1733. 7 145 1. 5 F3 N 11. 58 170 35. 82 230 21. 39 1217. 9 492; 0 1709. 9 145 1.5 F1 R 11. 35 190 33. 13 207 18. 72 1258. 9 387. 5 1646. 4 145 1.5 F2 R 9. 89 184 37. 4 1 194 25. 40 13 76. 7 492. 8 1869. 5 145 1.5 F3 R 9. 87 193 39. 48 211 18. 08 1523. 9 381. 5 1905. 4 145 0. 75 F3 R 10. 25 190 41. 40 187 14. 56 1573. 2 272. 3 1845. 5 145 .375 F3 R 10. 79 177 39. 25 186 25. 71 1389. 4 478. 2 1 867. 6 145 . 187 F3 R 11. 54 191 39. 52 245 11. 44 1509. 7 286. 4 1796. 1 170 1 F1 N 11. 07 175 36. 33 230 9. 77 1271. 5 449. 4 1720. 9 170 1 F2 N 10. 68 160 36. 77 230 11. 71 1309. 0 538. 7 1847. 7 170 1 F3 N 10. 30 178 40. 28 242 8. 46 1434. 0 409. 4 1843. 4 170 1 F1 R 9. 42 174 40. 93 29 8 9. 24 14 24. 4 550. 7 1975. 1 170 1 F2 R 9. 59 177 40. 19 250 10. 32 1422. 7 516. 0 1938. 7 170 1 F3 R 8. 91 181 45. 32 300 9. 33 1640. 6 559. 8 2200. 4 170 0. 75 F3 R 9. 26 175 46. 20 323 7. 53 1617. 0 486. 4 2103. 4 170 0. 5 F3 R 9. 57 175 45. 88 254 9. 38 1605. 8 476. 5 2082. 3 170 0. 25 F3 R 9. 89 178 40. 50 290 9. 44 1441. 8 547. 5 1989. 3 (Continue next page) 150 I I I . SAPWOOD T t M L SR 1F A1T 2F A2T 1 FT 2FT TTO 100 4 S3 N 24. 97 136 5.38 312 28.26 146. 3 881. 7 1028.0 100 4 S3 B 23. 92 145 5.43 310 27.20 157. 5 843. 2 1000. 7 120 2 S3 N 23. 19 142 7.38 285 24.34 209. 6 693. 7 903. 3 120 2 S3 R 24.04 151 7.59 26 4 25.06 218. 6 660. 0 878. 6 170 1 S3 N 21. 59 139 9.22 252 12. 18 256. 3 613. 9 870.2 170 1 S3 R 19.60 153 9.13 231 13.78 279. 4 636. 6 916. 0 IV. HEARTWOOD T t M L SB 1F A1T 2F A2T 1 FT 2FT TTO 100 4 H3 N 22. 80 131 5.21 265 25.49 136. 5 675. 5 812. 0 100 4 H3 R 23. 00 144 4.77 305 17.38 137. 4 530. 1 667. 5 120 2 H3 N 23. 05 138 6.21 29 6 17. 63 171. 4 521. 8 693. 2 120 2 H3 R 21.90 144 6.54 247 21.36 188. 4 527. 6 716. 0 170 1 H3 N 20.89 135 7.66 290 7.49 206. 8 434. 4 641. 2 170 1 H3 R 18.61 137 7.86 280 7.12 215. 4 398. 7 614. 1 T = cooking temperature, °C. t = cooking time, hr at max. temp. M = m a t e r i a l (1, 2, and 3 repr e s e n t c o a r s e , medium and f i n e f r a c t i o n s , r e s p e c t i v e l y . ) L = l i g u o r v a r i e t y (N= o r i g i n a l l i g u o r ; B= o r i g i n a l l i g u o r + 5 g/1 sodium hyd r o x i d e ) . SR = s o l i d r e s i d u e y i e l d . 1F = the i n i t i a l l i g u o r f r a c t i o n recovered, ml. A1T = 5 ml a l i q u o t of i n i t i a l l i g u o r t a l l o i l y i e l d , mg. 2F = the second l i g u o r f r a c t i o n , ml. A2T = 10 ml (except f o r 170°C sample, which used 5 ml) a l i q u o t of second l i q u o r f r a c t i o n t a l l o i l y i e l d , mg. 1 FT = i n i t i a l l i g u o r f r a c t i o n t a l l o i l y i e l d estimate, mg. 2FT = second l i g u o r f r a c t i o n t a l l o i l y i e l d e s timate; mg. TTO = combined crude t a l l o i l y i e l d , mg. * i n d i c a t e s leak during cooking. 151 Appendix 4. Data and eguations f o r BLE c a l c u l a t i o n s . I. EMPIRICAL EXPRESSIONS FOR BLE SR YIELDS 1. THE DATA Parameters Bark T e c h n i c a l F o l i a g e T (OC) time* SR SR/W In(SR/W) W/SR SR SR/W In (SR/W) W/SR 80 1.5 15.76 . 788 -.2380 1. 269 15.92 .796 -.2282 1.256 3.0 14.73 .758 -.2777 1. 320 15.38 .769 -.2627 1.300 6.0 13. 54 .677 -.3901 1. 477 14.70 . 735 -.3079 1.360 12.0 12.36 .618 -.4817 1. 618 13. 45 . 673 -.3968 1.487 100 0.5 15.20 . 760 -.2744 1. 316 14.91 .746 -.2937 1.341 1 .0 14.38 .719 -.3299 1. 391 14.83 .742 -.2991 1.349 2.0 13.85 . 693 -.3674 1. 444 13.59 .680 -.3864 1. 472 4.0 11 .68 . 584 -.5379 1. 712 12.87 . 644 -.4408 1. 554 120 0.25 11.91 . 596 -.5183 1. 679 12.75 . 638 -.4502 1.569 0.5 11.12 . 556 -.5870 1 . 799 12.06 .603 -.5058 1. 658 1.0 10.75 . 538 -.6208 1. 860 11.72 . 586 -.5244 1. 70 6 2.0 9.69 .485 -.7246 2. 064 11.20 . 560 -.5798 1.78 6 145 . 187 9.48 . 474 -.7468 2. 110 11.54 . 577 -.5499 1 .733 . 375 9.08 . 454 -.7892 2. 203 10.79 . 540 -.6171 1.854 0.75 8.64 .432 -.8393 2. 315 10.25 .513 -.6684 1. 951 1.5 7. 98 .399 -.9188 2. 506 9.87 . 494 -.7062 2.026 170 0.25 7.61 . 381 -.9663 2. 628 9.89 .495 -.7042 2.022 0.5 7.45 . 373 -.9875 2. 685 9.57 .479 -.7371 2.090 0. 75 7.30 .365 -1.008 2. 740 9.26 . 463 -.7700 2. 160 1.0 7.23 .362 -1.017 2. 766 8.91 . 446 -.8086 2. 245 * r e f e r s t o the time at maximum temperature: SR i s s o l i d r e s i d u e y i e l d . W i s the sample weight base f o r c a l c u l a t i o n , 20 g i s assumed f o r a l l data. 152 2. KINETIC DETERMINATIONS F i r s t - o r d e r Eguations Temp, (oc) Bark T e c h n i c a l F o l i a g e 80 Y=- .216 - .0233X, (r=. 979) Y=-. 211 - .0157X, (r = . 99 8) 100 Y=-.241 - .0728X, (r=. 991) Y=-. 272 - .0444X, (r=. 966) 120 Y=- .511 - .1088X, (r=. 980) Y=-. 456 - .0660X, (r=. 942) 145 Y=- . 735 - .1261X, (r=. 990) Y=-. 560 - .1069X, (r=. 917) 170 Y=-.952 - .0690X, (r=. 986) T=-. 668 - .1384X, (r=. 999) Second-order Eguations Temp, (oc) Bark T e c h n i c a l F o l i a g e 80 Y = 1. 232 + .0335X, (r=. 983) Y= 1. 229 + .0216X, (r=. 999) 100 Y= 1. 259 + .1 101X, (r=. 989) Y= 1. 308 + .0643X, (r=. 969) 120 T= 1. 658 + .2047X, (r=. 984) Y = 1. 575 + .1114X, (r=. 950) 145 Y= 2. 079 + .2915X, (r=. 993) Y= 1. 749 + .2018X, (r=. 925) 170 Y= 2. 588 + .1876X, (r=- 988) Y= 1. 945 + .2956X, (r=. 999) The independent v a r i a b l e i s time at maximum temperature; Dependent v a r i a b l e f o r f i r s t order eguations i s In (SR/W); and f o r second order eguations i s W/SR. 153 3 3. ARRHENIUS FUNCTIONS FOR APPARENT ENERGIES OF ACTIVATION Bark In (rate) F o l i a g e In (rate) Temp °K 1/Temp. F i r s t Second F i r s t Second 3 53 0.002833 -3. 760 -3.395 -4.154 -3.835 373 0.002681 -2. 620 -2.206 -3. 112 -2.744 393 . 0.002544 -2.218 -1.586 -2.717 -2.195 418 0.002392 -2.071 -1.23 3 -2.236 -1.600 443 0.002257 (-2. 674) (-1. 673) -1.977 -1.219 4. REGRESSION EQUATIONS FOR APPARENT ENERGIES OF ACTIVATION E e a c t i o n Order Bark T e c h n i c a l F o l i a g e F i r s t - o r d e r Y=7.133-3751.1X, (r=. 925) Y=6. 41 6-3641. 7X , (r = . 970) Second-order Y=1 0. 62-486 9. 8X, (r=. 967) Y=8. 953-4435. 3X, (r=. 984) 

Cite

Citation Scheme:

        

Citations by CSL (citeproc-js)

Usage Statistics

Share

Embed

Customize your widget with the following options, then copy and paste the code below into the HTML of your page to embed this item in your website.
                        
                            <div id="ubcOpenCollectionsWidgetDisplay">
                            <script id="ubcOpenCollectionsWidget"
                            src="{[{embed.src}]}"
                            data-item="{[{embed.item}]}"
                            data-collection="{[{embed.collection}]}"
                            data-metadata="{[{embed.showMetadata}]}"
                            data-width="{[{embed.width}]}"
                            async >
                            </script>
                            </div>
                        
                    
IIIF logo Our image viewer uses the IIIF 2.0 standard. To load this item in other compatible viewers, use this url:
http://iiif.library.ubc.ca/presentation/dsp.831.1-0095167/manifest

Comment

Related Items