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Studies on the holocellulose of Sitka spruce : methylation of spruce holocellulose Martin, Arthur James 1951

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Of. i STUDIES ON THE HOLOCELLULOSE OF SITKA SPRUCE METHYLATION OF SPRUCE HOLOCELLULOSE by Arthur James Martin  A Thesis Submitted I n P a r t i a l Fulfilment of the Requirements f o r the Degree of Master of Arts i n the Department of Chemistry  We accept t h i s thesis as conforming to the standard  required from candidates f o r the degree of Masper ^of Arts  Members of the Department of Chemistry  The U n i v e r s i t y of B r i t i s h Columbia A p r i l , 1951  ABSTRACT S i t k a Spruce holocellulose has been prepared by the c h l o r i t e procedure as modified by Wise and associates. This m a t e r i a l has been subjected to successive methylations.  The  methoxyl content and y i e l d of the s o l i d residue were determined a f t e r each methylation and the methoxyl contents have been compared with corresponding values obtained when extractive-free wood was treated i n the same manner.  The methoxyl contents and  y i e l d s of m a t e r i a l present i n the liquors from the f i r s t methylat i o n have also been determined.  ACKNOWLEDGEMENT The author wishes to take t h i s opportunity t o thank Dr. E . V. White f o r h i s suggestions and h e l p f u l c r i t i c i s m and to thank the Forest Products Laboratory f o r supplying the S i t k a Spruce sample used i n t h i s research.  TABLE OF CONTENTS Introduction (i) (ii)  ,  Components p r e s e n t i n wood .  (iv)  1  R e l a t i o n s h i p between a l p h a - c e l l u l o s e , hemic e l l u l o s e and l i g n i n  (iii)  Page  4  Development o f the method f o r i s o l a t i n g h o l o cellulose  5  Development o f m e t h y l a t i o n and i t s a p p l i c a t i o n  9  Purpose o f Study  12  E x p e r i m e n t a l Methods and R e s u l t s (i)  P r e p a r a t i o n o f wood sample  12  M e t h y l a t i o n o f the e x t r a c t i v e - f r e e spruce wood  13  (iii)  Preparation of chlorite holocellulose  15  (iv)  Methylation of c h l o r i t e holocellulose  15  Treatment o f m e t h y l a t i o n l i q u o r  17  (ii)  (v) Discussion  18  B i b l i o g r aphy  23  1.  Studies on the Holocellulose of S i t k a Spruce Methylation of Spruce Holocellulose INTRODUCTION ( i ) Components present i n wood. Wood i s composed of holocellulose (70 to 80%),  lignin  (18 to 27%) and a small f r a c t i o n (1.0%) of ash-forming minerals. These three f r a c t i o n s make up the wood structure, which i s i n f i l t r a t e d with water-soluble and ether-soluble  substances.  The  h o l o c e l l u l o s e , l i g n i n and minerals are w e l l d i s t r i b u t e d throughout •the wood structure. The consideration of wood components i s s i m p l i f i e d by d i v i d i n g these substances into four f r a c t i o n s : (a) ash-forming minerals,; (b) extractives, (c) l i g n i n and (d) h o l o c e l l u l o s e . (a) The ash-forming minerals i n a wood sample are determined by combustion o f the wood t o remove a l l organic material. On analysis of the ash one f i n d s that the p r i n c i p a l m e t a l l i c components present are calcium, potassium and magnesium and that the p r i n c i p a l acid r a d i c a l s present are CO^, P^O^, SiO^ and SO^. Aluminum, i r o n , manganese, sodium and chlorides are present i n l i m i t e d amounts and traces of other inorganic components may be present. (b) Extractives are substances, which can be removed by extraction with neutral solvents.  Components present i n the ex-  t r a c t i v e s include wood r e s i n s , tannins, phenolic constituents and colouring matters.  The extractives are u s u a l l y present i n minute  amounts. (c) Although many procedures have been outlined f o r the  2. i s o l a t i o n of l i g n i n no method has as y e t been found t o i s o l a t e l i g n i n q u a n t i t a t i v e l y i n an unchanged s t a t e . known procedures  However by use  of  l i g n i n i s u s u a l l y o b t a i n e d as an amorphous p r o -  d u c t , which appears t o be o f h i g h m o l e c u l a r weight.  Experimental  d a t a from r e s e a r c h on the l i g n i n complex i n d i c a t e t h a t l i g n i n  has  a h i g h e r carbon content than the o r i g i n a l wood, t h a t h y d r o x y l groups and methoxyl groups are p r e s e n t and t h a t aromatic r e s i d u e s r e l a t e d t o phenylpropane appear t o be the b a s i c s t r u c t u r a l u n i t s . Mo  d e f i n i t e c o n f i g u r a t i o n has been assigned t o the l i g n i n complex  a l t h o u g h many p r o p o s a l s have been made r e g a r d i n g i t s s t r u c t u r e . (d) The  term h o l o c e l l u l o s e , meaning the whole or e n t i r e  carbohydrate m a t e r i a l , was  suggested by K u r t h and B i t t e r (1) t o  d e s c r i b e the t o t a l carbohydrate  f r a c t i o n o f e x t r a c t i v e - f r e e wood.  T h i s m a t e r i a l can be s e p a r a t e d i n t o two f r a c t i o n s ; the  alkali-  r e s i s t a n t f r a c t i o n , a l p h a - c e l l u l o s e , and the a l k a l i - s o l u b l e t i o n , the h e m i c e l l u l o s e s .  The  s e p a r a t i o n can be achieved by  fraca  m i l d e r a l k a l i treatment than t h a t r e q u i r e d f o r wood s i n c e the poss i b l e l i n k a g e s between the h e m i c e l l u l o s e s and l i g n i n have been broken. A l p h a - c e l l u l o s e , the f i b r o u s r e s i d u e l e f t a f t e r e x t r a c t i o n , i s l a r g e l y composed o f l o n g glucopyranose may  r e t a i n some mannose, x y l o s e and u r o n i c a c i d u n i t s .  alkaline  c h a i n s but I f these  i m p u r i t i e s are removed one would have a c e l l u l o s e f r a c t i o n s i m i l a r t o c o t t o n c e l l u l o s e , which i s b u i l t up of glucose r e s i d u e s j o i n e d by A -  1.4  linkages.  c h a i n molecule  C o t t o n c e l l u l o s e may  as i l l u s t r a t e d i n F i g u r e  1.  be f o r m u l a t e d as a l o n g  3.  Figure 1, Cotton C e l l u l o s e . The  a l k a l i - s o l u b l e f r a c t i o n , the hemicelluloses, i s com-  posed of two parts; the eellulosans and the polyuronide loses.  hemicellu-  The eellulosans and polyuronide hemicelluloses are short  chain polysaccharides.  Although t h e i r properties are very s i m i l a r  p a r t i c u l a r i l y with respect to s o l u b i l i t y i n dilute a l k a l i and t o h y d r o l y s i s by d i l u t e acids, they d i f f e r i n regard to t h e i r p o s i t i o n i n the wood.  The eellulosans are oriented and included i n the  c e l l u l o s e structure whereas the polyuronide hemicelluloses are incrusted i n the c e l l u l o s e along with l i g n i n . losans are simple pentosans and hexosans.  Chemically the e e l l u -  The polyuronide hemi-  c e l l u l o s e s d i f f e r s l i g h t l y i n that they contain uronie acid units a3 w e l l as sugar u n i t s . On hydrolysis of the hemicelluloses such sugars as xylose, mannose, glucose and to a l e s s e r extent arabinose and galactose are obtained.  The hemicelluloses as a whole are non-reducing and con^  t a i n most of the acetyl, uronic a c i d and methoxyl content of the holocellulose.  H H-oM •-  •H  'oH  CooM  OK /'  H  m  i OH ^  (\<lA«>tNOSE  F i g u r e 2. Sugars P r e s e n t  i n the H e m i c e l l u l o s e s .  ( i i ) R e l a t i o n s h i p betwenn a l p h a - c e l l u l o s e , h e m i c e l l u l o s e s and. l i g n i n . I n d i r e c t evidence  (2) has g i v e n an i n d i c a t i o n t h a t there  may be a chemical union between l i g n i n and the polyuronide celluloses.  Same o f t h i s evidence  nemi-  i s l i s t e d below;  (a) I t has been shown t h a t i t i s impossible t o remove l a r g e amounts o f carbohydrate without  m a t e r i a l from e x t r a c t i v e - f r e e wood  a l s o removing l i g n i n . (b) The s o l u b i l i t y o f wood h e m i c e l l u l o s e s  increases  markedly when preceded by c h l o r i n e d e l i g n i f i c a t i o n . (c) I s o l a t e d h e m i c e l l u l o s e s were r e a d i l y h y d r o l y z e d by c e r t a i n enzymes b u t h e m i c e l l u l o s e s , when s t i l l i n the c e l l w a l l , were extremely r e s i s t a n t t o enzymatic h y d r o l y s i s . (d) M e t h y l a t i o n o f l i g n i n i n the o r i g i n a l wood d i d n o t r a i s e the methoxyl c o n t e n t o f the l i g n i n b u t when the wood was g e n t l y h y d r o l y z e d b e f o r e m e t h y l a t i o n the methoxyl content o f the lignin  increased.  However although  the above r e s u l t s appear t o f a v o u r a p o s s i b l e  l i g n i n - h e m i c e l l u l o s e chemical u n i o n no d i r e c t evidence  has y e t been  o b t a i n e d t o d e f i n i t e l y e s t a b l i s h the presence o f chemical  linkages.  One can a l s o c o n s i d e r t h e p o s s i b i l i t y o f chemical between the c e l l u l o s e and the h e m i c e l l u l o s e s . l o s e s , b o t h c e l l u l o s a n s and polyuronide  linkages  Since the h e m i c e l l u -  h e m i c e l l u l o s e s , can be  removed by a l k a l i n e e x t r a c t i o n , i n d i c a t i o n s are t h a t a m e c h a n i c a l mixture i s present.  However the a l k a l i n e e x t r a c t i o n may cause the  breakdown o f c h e m i c a l bonds so t h a t w i t h the e x p e r i m e n t a l d a t a a v a i l a b l e no a s s e r t i o n c o n c e r n i n g a p o s s i b l e u n i o n c a n be made. Wise (2) (3) has attempted t o g i v e a schematic c o n c e p t i o n o f the p o s s i b l e r e l a t i o n s h i p between the a l p h a - c e l l u l o s e , hemic e l l u l o s e s and l i g n i n . £  H i s scheme i s shown i n F i g u r e  Increasing  chain l e n g t h — —  A.  HOLOCELLULOSE  3.  Hemicellulose €b / p r o b a b l y i n "part chemically, combined with l i g n i n .  .. ALPHA-CELLULOSE ( a n a l y t i c a l l y define*  <— "TRUE"CELLULOSE (long chains of/3-DT glycopyranose u n i t s \  HEMICELLULOSE  LIGNIN -  .Border-zone between the h e m i c e l l u l o s e s and t r u e c e l l u l o s e ,  Figure  3.  ( i i i ) Development o f the method f o r i s o l a t i n g h o l o c e l l u l o s e . Holocellulose provides  an i d e a l source o f m a t e r i a l f o r  i n v e s t i g a t i o n s on the n a t u r e and a s s o c i a t i o n o f the  polysaccharide  components i n the c e l l w a l l and would serve as a s t a r t i n g m a t e r i a l  f o r a thorough study o f the h e m i c e l l u l o s e s o f the wood sample. However a r a p i d and simple method was r e q u i r e d f o r the i s o l a t i o n of t h e e n t i r e carbohydrate c o n t e n t o f the e x t r a c t i v e f r e e wood as a single  fraction. The i s o l a t i o n o f h o l o c e l l u l o s e from wood c o n s i s t s i n the  removal o f t h e l i g n i n and the r e t e n t i o n o f t h e carbohydrate m a t e r i a l . L i g n i n i s removed from the wood as l i g n i n c h l o r i d e by the use o f a suitable  solvent. The f i r s t attempt t o i s o l a t e the e n t i r e carbohydrate f r a c -  t i o n was made i n 1921 by Schmidt  and Graumanni ( 4 ) , when they r e p o r t e d  t h a t i n c r u s t i n g substances c o u l d be removed q u a n t i t a t i v e l y by success i v e treatments w i t h s o l u t i o n s o f c h l o r i n e d i o x i d e (ClO^) and sodium sulfite  (Na^SOj).  erial.  Schmidt  These r e a g e n t s d i d n o t a t t a c k carbohydrate mat-  and Duysen (5) l a t e r found t h a t a s o l u t i o n o f c h l o r i n e  dioxide i n acetic  a c i d c o u l d be used as a reagent t o d i s s o l v e the  i n c r u s t a t i o n s and thus remove them from the p l a n t m a t e r i a l . numerous m o d i f i c a t i o n s have been made on the o r i g i n a l p r o cedure.  Schmidt, Tang and Jandebauer  (6) suggested a "one s t e p "  method whereby the c h l o r i n e d i o x i d e treatment was c a r r i e d out i n aqueous p y r i d i n e  and a phosphate  b u f f e r o f pH. 6.8 w i t h the r e s u l t  t h a t the l i g n i n was removed b y one treatment.  L a t e r the same workers  C7) s t a t e d t h a t t h e q u a n t i t y o f p y r i d i n e r e q u i r e d t o c o n v e r t the w a t e r - i n s o l u b l e o x i d a t i o n product o f l i g n i n i n t o w a t e r - s o l u b l e prod u c t s i s 30 p e r c e n t weight o f t h e wood and t h a t w i t h f i v e t o e i g h t t i m e s t h i s q u a n t i t y o f p y r i d i n e h y d r o l y t i c changes i n the s k e l e t o n substances can be l a r g e l y p r e v e n t e d .  Schmidt named the carbohydrate  r e s i d u e " S k e l e t t s u b s t a n z " . U n f o r t u n a t e l y the procedure  requires  seventeen - t w e n t y - s i x days i f q u a n t i t a t i v e y i e l d s are t o be o b t a i n e d .  7. Tang and Wang (8) attempted t o shorten t h e r e a c t i o n by  i n c r e a s i n g the c o n c e n t r a t i o n s  succeeded i n r e d u c i n g  period  o f the reagents b u t although they  the time r e q u i r e d t o seven - nine days t h e  y i e l d o f the carbohydrate m a t e r i a l was reduced. I n 2333, R i t t e r and K u r t h (1) improved t h e procedure by using  a 15 p e r cent a l c o h o l i c s o l u t i o n o f p y r i d i n e  and c h l o r i n e . The  r e p e a t e d a l t e r n a t e treatments o f the e x t r a c t i v e - f r e e wood w i t h these r e a g e n t s removed i n about t e n hours a l l except a s m a l l percentage o f the  l i g n i n which was removed i n t h i r t y minutes w i t h a s o l u t i o n o f  calcium  hypochlorite  (pH. 7.0 - 7.5). T h i s method was a p p l i c a b l e t d  t h e hardwoods b u t had t o be m o d i f i e d  f o r softwoods. The m o d i f i c a t i o n s  made f o r t h e softwoods c o n s i s t e d o f changing the p y r i d i n e concent r a t i o n from 15 p e r c e n t t o 50 p e r c e n t and o m i t t i n g the b l e a c h treatment ( 9 ) . Van isolating  Beckum and R i t t e r (10) d e v i s e d  a procedure f o r  h o l o c e l l u l o s e i n which e x t r a c t i v e - f r e e wood sawdust i s  a l t e r n a t e l y t r e a t e d w i t h c h l o r i n e gas and a s o l u t i o n o f h o t 95 p e r c e n t a l c o h o l c o n t a i n i n g 3 p e r c e n t monoethanolamine.  The time r e -  q u i r e d f o r the d e t e r m i n a t i o n i s l e s s t h a n t h r e e hours and a r a t h e r sharp c o l o u r end p o i n t i s o b t a i n e d when the l a s t t r a c e o f l i g n i n i s removed.  The monoethanolamine i s used t o n e u t r a l i z e any hydro-  c h l o r i c a c i d formed d u r i n g the r e a c t i o n and a l s o t o m a i n t a i n the s o l v e n t s l i g h t l y b a s i c so as t o i n c r e a s e lignin chloride.  i t s s o l v e n t a c t i o n on the  They found t h a t 75°C was the approximate minimum  temperature a t which the end p o i n t c o l o u r change was r e l i a b l e f o r d e t e c t i n g s m a l l amounts o f r e s i d u a l l i g n i n Thomas (11) m o d i f i e d  chloride.  the technique s l i g h t l y by c a r r y i n g  out the i n i t i a l c h l o r i n a t i o n s on the wood meal suspended i n c o l d  8. carbon t e t r a c h l o r i d e thereby e l i m i n a t i n g the use o f water as f a r as p o s s i b l e t h e n completing d e l i g n i f i c a t i o n as b e f o r e .  Thomas a l s o  n o t i c e d t h a t the n i t r o g e n content of the h o l o c e l l u l o s e was  about  three times t h a t of the wood i n d i c a t i n g t h a t some monoethanolamine or ammonium s a l t s were adsorbed by the h o l o c e l l u l o s e . Wise, Murphy and D'Addieco (12) confirmed Thomas  findings  1  and have i n d i c a t e d t h a t the amount o f monoethanolamine r e t a i n e d  was  approximately e q u a l t o the carbohydrate m a t e r i a l l o s t and l e d t o summations t h a t appeared t o account f o r the e n t i r e wood substance. Another technique f o r i s o l a t i n g h o l o c e l l u l o s e has been developed by Jayme ( 1 3 ) . He  o b t a i n e d almost t h e o r e t i c a l y i e l d s o f  h o l o c e l l u l o s e from v a r i o u s wood samples by t r e a t i n g w i t h sodium chlorite was  (NaClO^) i n d i l u t e  acetic acid.  c a r r i e d out at 60° C f o r twelve h o u r s .  The c h l o r i t e treatment The r e s i d u e was  filtered-  and washed and s u b j e c t e d t o t h r e e more s u c c e s s i v e c h l o r i t i n g s f o r t w e l v e , e i g h t and e i g h t hours each. A f t e r each treatment the wood r e s i d u e was  a g a i n f i l t e r e d and washed. The f i n a l white r e s i d u e how-  e v e r s t i l l r e t a i n e d 2.8 t o 3.5 p e r cent l i g n i n . Jay©e found t h a t i f t h i s was removed by more d r a s t i c a c t i o n carbohydrate m a t e r i a l  was  l o s t simultaneously. Wise (14) s t u d i e d Jayme*s procedure and d e v i s e d c e r t a i n modifications.  He heated the u n e x t r a c t e d wood meals t o 60°C  and  a l l o w e d the samples t o stand at 30°C f o r about twenty-four hours w i t h an aqueous s o l u t i o n o f sodium c h l o r i t e  and a c e t i c a c i d u n t i l  t h e samples were n e a r l y d e l i g n i f i e d . I n the case of spruce he found t h a t a second (one hour) c h l o r i t e treatment was  necessary.  Wise, Murphy and D'Addieeo (12) have found t h a t i t i s unnecessary t o use the p r o l o n g e d c h l o r i t e treatments d e s c r i b e d by  9. Jayme and t h a t i t i s unnecessary t o f i l t e r the wood r e s i d u e a f t e r e a c h treatment.  I n g e n e r a l , the c h l o r i t i n g treatments c o u l d be  completed w i t h i n f o u r hours.  Complete removal o f the l i g n i n caused  a marked l o s s o f h e m i c e l l u l o s e which j u s t i f i e d Jayme's i n s i s t e n c e t h a t the t e n a c i o u s l i g n i n be l e f t Civ)  i n the h o l o c e l l u l o s e .  Development o f m e t h y l a t i o n and i t s a p p l i c a t i o n t o the d e t e r -  m i n a t i o n of the s t r u c t u r e of c e l l u l o s e . A f t e r a p o l y s a c c h a r i d e has been i s o l a t e d the next step i s t o i n v e s t i g a t e i t s fundamental s t r u c t u r e .  P o l y s a c c h a r i d e s are  systems b u i l t up from simple sugars and sugar d e r i v a t i v e s , are  l i n k e d g l y c o s i d i c a l l y i . e . the l i n k a g e between the  sugars i s an a c e t a l t y p e . c h e m i s t was the  and is  individual  T h e r e f o r e the main problem o f the sugar  t o l o c a t e which h y d r o x y l i n a sugar i s l i n k e d t o  a l d e h y d i c h y d r o x y l g r o u p i n g of another sugar. One  the  which  o f the b e s t methods used f o r l o c a t i n g the p o s i t i o n o f  linkage i s methylation.  W i t h t h i s procedure one  attempts t o  r e p l a c e the hydrogen i n the h y d r o x y l groups n o t i n v o l v e d i n the l i n k a g e by a m e t h y l group.  Then on h y d r o l y s i s the g l y c o s i d i c  ages would be broken and f r e e h y d r o x y l groups would be l e f t  link-  i n the  sugar m o l e c u l e , which would i n d i c a t e the p o s i t i o n o f the g l y c o s i d i c l i n k a g e , s i n c e the methoxyl groups most o r d i n a r y r e a g e n t s .  Then the methylated sugar d e r i v a t i v e i s  i d e n t i f i e d and the p o i n t of l i n k a g e The f i r s t  determined.  attempt t o prepare a l k y l a t e d sugars was made by  F u r d i e and I r v i n e ( 1 5 ) . and an a l k y l i o d i d e  are r e s i s t a n t t o the a c t i o n o f  These i n v e s t i g a t o r s used d r y s i l v e r oxide  as a l k y l a t i n g agents.  Since the s i l v e r oxide has  s t r o n g o x i d i z i n g p r o p e r t i e s the methyl g l y c o s i d e s of the sugars have  10. to  be used.  The method has several, f a i l i n g s such as the use o f  expensive r e a g e n t s , the n e c e s s i t y f o r f i n d i n g a s u i t a b l e for  the sugar i n the i n i t i a l  solvent  stages o f the r e a c t i o n and f i n a l l y the  m i x t u r e o f unchanged and p a r t l y a l k y l a t e d m a t e r i a l r e s u l t i n g from the r e a c t i o n i s complex and d i f f i c u l t t o s e p a r a t e .  A l t h o u g h the method  i s used i n some cases t o g i v e a c o m p l e t e l y m e t h y l a t e d p r o d u c t , s i n c e t h e p a r t i a l l y m e t h y l a t e d m a t e r i a l s are s o l u b l e i n methyl i o d i d e , i t i s n o t g e n e r a l l y a p p l i c a b l e a t the p r e s e n t time. a l k y l a t i n g sugars was  f i r s t used by Denham and Woodhouse (16) i n  1913 when t h e y m e t h y l a t e d c e l l u l o s e . of  methylating cellulose  They attempted v a r i o u s methods  and found t h a t m e t h y l a t i o n c o u l d be  b y the a c t i o n of d i m e t h y l s u l f a t e  [ ( C H ^ SO^j  i t had been impregnated w i t h 15 p e r c e n t NaOH. of  Another method f o r  efected  on the c e l l u l o s e  after  They used an excess  each r e a g e n t and found t h a t the r e a c t i o n proceeded i n s t a g e s .  t r e a t i n g the c e l l u l o s e  By  a l t e r n a t e l y w i t h a l k a l i and d i m e t h y l s u l f a t e  t h e y o b t a i n e d a mixture o f methylated sugars, from which they i s o l a t e d a compound approximating a t r i m e t h y l g l u c o s e .  L a t e r Denham (17)  attempted t o prepare a h i g h l y methylated c e l l u l o s e by r e p i t i t i o n s of the procedure, which c o n s i s t e d of t r e a t i n g c o t t o n , which had been soaked i n sodium h y d r o x i d e , w i t h d i m e t h y l s u l f a t e . p r o d u c t c o n t a i n i n g 44.6 p e r c e n t methoxyl t r i m e t h y l g l u c o s e i s 45.6  per c e n t ) .  He o b t a i n e d a  (the t h e o r e t i c a l v a l u e f o r  A slow r a t e of i n c r e a s e o f  methoxyl was n o t e d i n the f i n a l stages o f the m e t h y l a t i o n , an i n d i c a t i o n t h a t the l i m i t had been n e a r l y reached. of  The f i b r o u s s t r u c t u r e  c e l l u l o s e was found t o p e r s i s t i n h i g h l y methylated p r e p a r a t i o n s . Haworth (18), a p p l i e d the method t o v a r i o u s sugars and  sugar d e r i v a t i v e s . to  He found t h a t t h e r e was no d e t r i m e n t a l e f f e c t  the i n t r o d u c t i o n of a l k a l i .  From h i s experiments he a l s o n o t e d  t h a t d u r i n g the a l k y l a t i o n an a c i d medium should be avoided^  due  11. since the a c i d would cause h y d r o l y s i s of the g l y c o s i d i c l i n k a g e s and t h a t a s t r o n g l y a l k a l i n e medium s h o u l d be avoided t o exclude the poss i b i l i t y of the f o r m a t i o n of complex e n o l i c d e r i v a t i v e s and He used an excess o f the a l k y l a t i n g agents q u a n t i t y ) and m a i n t a i n e d A slight  a slight  ( t h r e e times  a l k a l i n i t y throughout  resins.  theoretical the r e a c t i o n .  a l k a l i n i t y i s a l s o d e s i r e d at the end of the r e a c t i o n t o  d e s t r o y any excess d i m e t h y l s u l f a t e . I r v i n e , H i r s t and co-workers (19, 20, 21) c o n t i n u e d Denham's work on c o t t o n c e l l u l o s e  and suggested  a probable  structure f o r c e l l -  u l o s e based on the 2.3.6. t r i m e t h y l glucose o b t a i n e d from the ation.  S i n c e the f r e e h y d r o x y l s were p r e s e n t i n the one  methyl-  and f i v e  p o s i t i o n s , i n d i c a t i o n s were t h a t these p o s i t i o n s were p r o t e c t e d from methylation.  They deduced t h a t c e l l u l o s e was  i n which p o s i t i o n s one glucose residues.  a d e r i v a t i v e of glucose  and f i v e are s u b s t i t u t e d by one or more anhydro-  However t h e i r deductions are based on a 1-4 i n -  t e r n a l l i n k a g e i n the glucose molecule  so t h a t a c c o r d i n g t o p r e s e n t  day i d e a s i n which the l i n k a g e i s pyranose v a r i o u s sugar" molecules  are a t the one  " F i g u r e 4.  (1-5) the bonds between  and f o u r p o s i t i o n s .  2).  2.3.6. T r i m e t h y l Glucose  The m e t h y l a t i o n technique p l a y e d an important r o l e i n the e l u c i d a t i o n of the s t r u c t u r e of c e l l u l o s e  and has been u s e f u l i n  determining the s t r u c t u r e of other p o l y s a c c h a r i d e s .  12. PURPOSE OF STUDY The cellulose.  o b j e c t o f t h i s r e s e a r c h i s t o methjilate spruce  Since  the h e m i c e l l u l o s e s  present  holo-  i n the h o l o c e l l u l o s e  are s o l u b l e i n a l k a l i the p o s s i b i l i t y e x i s t s t h a t these components w i l l be e x t r a c t e d by the m e t h y l a t i o n  liquor.  F o r t h i s r e a s o n the  methoxyl c o n t e n t s and y i e l d s o f b o t h the i n s o l u b l e r e s i d u e s o l u b l e m a t e r i a l are t o be determined a f t e r the f i r s t  and  the  methylation.  A comparison i s t o be made between the r a t e o f m e t h y l a t i o n  of  the  i n s o l u b l e m a t e r i a l and the e x t r a c t i v e - f r e e spruce wood. EXPERIMENTAL ( i ) Preparation  o f wood sample.  A sample of S i t k a Spruce ( P i c e a S i t c h e n s i s ) heartwood obtained  was  from the F o r e s t Products L a b o r a t o r y at the U n i v e r s i t y of  B r i t i s h Columbia.  The  sample was  cut i n t o small blocks  ground i n t o a f i n e sawdust i n a W i l e y M i l l . would pass through a 40 mesh screen but not  and  then  The m a t e r i a l , which a 60 mesh screen,  was  then c o l l e c t e d . Batches of the  sawdust (150 grams each) were e x t r a c t e d f o r  10 hours i n a S o x h e l t  e x t r a c t o r w i t h 1250  benzene mixture (1-2)  u n t i l 600  mis.  o f an e t h y l a l c o h o l -  grams of the e x t r a c t i v e - f r e e m a t e r i a l  were p r e p a r e d . A q u a n t i t a t i v e determination sample was  of the e x t r a c t i v e s i n the wood  made i n the f o l l o w i n g manner. Samples o f the  grams each) were e x t r a c t e d i n a S o x h e l t an e t h y l alcohol-benzene mixture (1-2)  sawdust (2  e x t r a c t o r w i t h 200 mis. f o r 8 hours.  The  extractor  f l a s k , the weight o f which had been determined, v/as removed and s o l v e n t evaporated o f f u s i n g a steam b a t h .  The  f l a s k was  an oven at 100°to 105°C f o r an hour and then weighed.  of  the  d r i e d i n -_  The  difference  13.. i n weight was  r e c o r d e d . The percentage  alcohol-benzene  soluble  m a t e r i a l on a m o i s t u r e - f r e e b a s i s was found t o be 1.51% 10.03%. ( i i ) M e t h y l a t i o n o f the e x t r a c t i v e f r e e spruce wood. A p r e l i m i n a r y i n v e s t i g a t i o n was made on the e x t r a c t i v e f r e e spruce sawdust t© f i n d out where l o s s e s o f m a t e r i a l would occur and t o become f a m i l i a r w i t h the technique o f m e t h y l a t i o n as applied to cellulosio-type materials. A 25 gram sample of the a i r - d r i e d e x t r a c t i v e - f r e e and 250 mis, of H^p which was  sawdust  were p l a c e d i n a t h r e e necked round bottom f l a s k ,  f i t t e d w i t h a g l a s s s t i r r e r and two graduated  dropping  f u n n e l s , one o f which c o n t a i n e d 30% sodium hydroxide s o l u t i o n the other d i m e t h y l s u l f a t e [(CH ) S0^. 3  o u s l y u n t i l the procedure was  %  The mixture was  completed.  and  stirred vigor-  Ten m i s . o f the sodium  hydroxide s o l u t i o n were added and t h e n b o t h r e a g e n t s were added dropwise  (approximately 1 ml. per minute) u n t i l 166 m i s . of HaOH and  m i s . o f [ ( C H ^ S O ^ j h a d been added over a p e r i o d of 2 hours.  The  150 temp-  e r a t u r e was m a i n t a i n e d at 25°C d u r i n g the r e a c t i o n by the use o f a water b a t h .  A s l i g h t a l k a l i n i t y was m a i n t a i n e d throughout the r e -  a c t i o n and p e r s i s t e d at the end of the r e a c t i o n . o f the r e a g e n t s the temperature  o f the water b a t h was  and m a i n t a i n e d a t t h i s temperature remaining  ?i  v  r a i s e d t o 50° C  f o r one h a l f hour t o d e s t r o y any  H  A s m a l l sample was removed and t h i s sample  t h e n washed w i t h water, d i l u t e sample was  acetic  was  a c i d and f i n a l l y w i t h water.  t h e n oven-dried f o r one hour a t 100°C.  o f the m a t e r i a l was procedure  addition  j(CH ) S0 ]. The mixture was t h e n f i l t e r e d w i t h s u c t i o n and  washed w i t h water.  The  A f t e r the  The  remainder  r e t u r n e d t o the t h r e e necked f l a s k and the above  r e p e a t e d u n t i l a t o t a l o f seven m e t h y l a t i o n s had been made. The methoxyl content of each sample from the above pro-  cedures was  then determined.  However b e f o r e d e t e r m i n a t i o n s were  14. made on the methylated wood samples, the methoxyl content o f v a n i l l i n £20.4%) was determined.  The technique was a p p l i e d t o v a n i l l i n  until  r e s u l t s , which were accurate and which c o u l d be d u p l i c a t e d , were obtained.  Clark's  whereby the ether  methoxyl procedure (22) i s a v o l u m e t r i c  method  i s treated with constant-boiling, hydriodic  under an atmosphere o f CO.^.  acid  The f o l l o w i n g r e a c t i o n t a k e s p l a c e ;  R0CH + HI — » ROH -V CH^I 3  The  v o l a t i l e i o d i d e i s c o l l e c t e d i n an a c e t i c a c i d s o l u t i o n o f  CHjCOOK t o which a l i t t l e  Br  i s added.  t  The f o l l o w i n g  reactions  t h e n occur; CH I  Br^  3  IBr + 2 Br  t  The  CH Br + IBr 3  * 3 H^O « — > HIOj + 5 HBr  s o l u t i o n c o n t a i n i n g the i o d i c a c i d i s washed i n t o a f l a s k con-  t a i n i n g a l i t t l e CH COONa, the excess B r ^ i s removed w i t h HCOOH, 3  EI  i s added, the s o l u t i o n i s a c i d i f i e d w i t h H SO  I,  t i t r a t e d w i t h F a S 0,.  1  lf  and the l i b e r a t e d  The f o l l o w i n g m o d i f i c a t i o n s  of Clark's  procedure were made; a g e l a t i n capsule was used t o h o l d the sample i n s t e a d o f a c i g a r e t t e paper and the scrubbing s o l u t i o n c o n s i s t e d o f a mixture o f e q u a l p o r t i o n s  o f 5 p e r c e n t aqueous Fa^S^O^ and 5 p e r  c e n t CdSO. i n s t e a d o f water.  T  The c o n s t a n t b o i l i n g HI used was p r e -  p a r e d f o l l o w i n g C l a r k ' s method The mined. The  (23).  methoxyl c o n t e n t s o f the wood samples were then  deter-  The r e s u l t s are t a b u l a t e d i n Table 1 and p l o t t e d i n F i g u r e  values given  are the average o f two d e t e r m i n a t i o n s u n l e s s  5.  stated  otherwise. The m e t h y l a t e d spruce sawdust s t i l l r e t a i n e d the f i b r o u s appearance o f the unmethylated m a t e r i a l b u t was y e l l o w as opposed t o the t a n c o l o u r o f the o r i g i n a l  sample.  15. %  E x t r a c t i v e f r e e spruce wood ' After 1st methylation A f t e r 2nd m e t h y l a t i o n A f t e r 3rd methylation A f t e r 4th methylation A f t e r 5th methylation A f t e r 6th methylation A f t e r 7th methylation  GMe 5.0 19.3 24.1 25.0 25.8 26.8 27.2 28.0  t 0.4%  t  0.5% 0.2%  t  + ±  t  ±  *  0.3% 0.2% 0.1% 0.1%  x Average of 6 d e t e r m i n a t i o n s x* Average of 4 d e t e r m i n a t i o n s Table 1. S u c c e s s i v e M e t h y l a t i o n of E x t r a c t i v e - f r e e Spruce Wood. ( i i i ) P r e p a r a t i o n of c h l o r i t e  holocellulose.  A sample of 100 grams o f the extractive-fr§e spruce wood was  p l a c e d i n a 6 - l i t r e erlenmeyer  acetic  a c i d (10 mis.)  flask.  and sodium c h l o r i t e  Water (3200 m i s . ) , g l a c i a l (NaClO^) (30 grams) were  added i n t h a t o r d e r s i n c e a s l i g h t l y a c i d medium i s e s s e n t i a l . 125 ml. erlenmeyer t u r e was  was  i n v e r t e d i n t o the neck o f the f l a s k .  A  The mix-  heated a t 70° t o 80°C f o r one hour at the end of which time  10 m i s . g l a c i a l a c e t i c a c i d and 30 grams MeC10t were added and the h e a t i n g c o n t i n u e d f o r another hour.  Two  more p o r t i o n s o f the r e -  agents were added at h o u r l y i n t e r v a l s .  A t the end o f the four-hour  h e a t i n g p e r i o d the r e a c t i o n mixture was  c o o l e d i n an i c e bath,  t e r e d w i t h s u c t i o n , washed w i t h i c e water and acetone.  The  fil-  air^-dried  p r o d u c t was white i n c o l o u r and r e t a i n e d the f i b r o u s appearance o f t h e spruce sawdust.  Four batches of the m a t e r i a l were p r e p a r e d .  Civ) M e t h y l a t i o n o f c h l o r i t e  holocellulose.  Twenty-five gram-batches of a i r - d r i e d c h l o r i t e were methylated f o l l o w i n g the procedure  holocellulose  used f o r the m e t h y l a t i o n o f  t h e spruce meal. A t the s t a r t of the m e t h y l a t i o n i t was  n o t i c e d t h a t the  h o l o c e l l u l o s e t u r n e d r e d when i t came i n t o c o n t a c t w i t h the FaOH  5PR,Ut£  HoLOCCLLAJLoSb  SPRUCE  I o  I  \  I  %  1  1  VAJOOT>  i  J  a ^ K & WUM&ESL or s u e cess we NSTHYUVOOWS  -«  7  16. solution.  T h i s o c c u r r e d only w i t h the unmethylated m a t e r i a l .  The  o n l y other d i f f e r e n c e from the m e t h y l a t i o n o f spruce wood was a t the f i n a l stage. mixture  When the water b a t h temperature was r a i s e d t o 50°C the  foamed e x c e s s i v e l y r e s u l t i n g i n the l o s s o f m a t e r i a l .  the a d d i t i o n o f acetone  c o u l d n o t h i n d e r the foaming.  The  was then m o d i f i e d so t h a t i n s t e a d o f s t i r r i n g the mixture  Even  procedure f o r one  h a l f hour a t 50°C, s t i r r i n g was c o n t i n u e d f o r two t o three hours a f t e r the  a d d i t i o n o f the reagents  at a b a t h temperature o f 2 5 ° C -  A l s o as  the  amount o f m a t e r i a l t o be methylated, was s m a l l e r w i t h each suc-  c e e d i n g m e t h y l a t i o n the amounts o f reagents rased were a d j u s t e d accordingly. The determined  s o l i d r e s i d u e was weighed and the methoxyl content was  on samples from each m e t h y l a t i o n .  The samples f o r methoxyl  d e t e r m i n a t i o n were d r i e d i n an Abderhalden d r y i n g p i s t o l . are t a b u l a t e d i n Table 2 and Table 3.  The r e s u l t s  The v a l u e s f o r percentage  methoxyl from T a b l e 3 are p l o t t e d i n F i g u r e 5.  A l l v a l u e r g i v e n are  t h e average o f two d e t e r m i n a t i o n s u n l e s s s t a t e d otherwise.  1st  Product %  Batch Batch Batch Batch Batch  1 2 3 4 5  17.4 16.6 17.0 16.6 16.8  Methylation Yield moisture f r e e basis** (Me Lost * 0 * 0.2 13.2 t 0.2 13.9 ? 0 i 0 13.5  x One d e t e r m i n a t i o n  . >  2nd M e t h y l a t i o n , Yield moisture % OMe free basis  22.2X  22.2 23.8  * 0.4 i 0.2  lost.  Table 2. M e t h y l a t i o n o f h o l o c e l l u l o s e (22 grams o f m o i s t u r e - f r e e m a t e r i a l used)  15.8 16.0 15.2  17.  % Chlorite Holocellulose After 1st methylation A f t e r 2nd m e t h y l a t i o n A f t e r 3rd methylation A f t e r 4 t h methylakiea A f t e r 5th methylation A f t e r 6th methylation A f t e r 7th methylation * One d e t e r m i n a t i o n l o s t .  Y i e l d on a bone d r y b a s i s  OMe  1.46 17.0 22.2 25.3 25.8 29.4 30.5 31.5  t 0.1 t 0.2  * *  ±  0.4  i  0.3  *  0.1  *  :  '  —  13.2 grams 16.0 13.5 12.7 12.3 11.9 12.6 ' ~  Table 3. S u c c e s s i v e M e t h y l a t i o n o f H o l o c e l l u l o s e (Batch (22 grams o f m o i s t u r e - f r e e m a t e r i a l used) The methylated m a t e r i a l a f t e r the f i r s t a t i o n s was  3)  and second methyl-  white and f i b r o u s but a f t e r three m e t h y l a t i o n s the mater-  i a l became creamy i n c o l o u r although i t s t i l l r e t a i n e d i t s f i b r o u s structure. (v) Treatment of m e t h y l a t i o n  liquor.  S i n c e the g r e a t e s t l o s s o f m a t e r i a l o c c u r r e d d u r i n g the f i r s t m e t h y l a t i o n a d e t e r m i n a t i o n was to  made on the m e t h y l a t i o n  liquor  a s c e r t a i n the amount o f m a t e r i a l p r e s e n t . The  l i q u o r was  f i r s t d i a l y s e d f o r 48 hours t o remove i n -  organic m a t e r i a l present. d i a l y s i s was  The  volume o f l i q u i d p r e s e n t  after  noted.  A p o r t i o n of t h i s l i q u i d was  then reduced  i n volume by  e v a p o r a t i n g under reduced p r e s s u r e a t 50° t o 55°C. An a l i q u o t of t h i s c o n c e n t r a t e was  t h e n evaporated  to dryness i n an oven r e g u l a t e d to  g i v e a constant temperature of 65°C. a f t e r the e v a p o r a t i o n . m a t e r i a l was  A reddish-brown f i l m was  left  The weight and methoxyl content of the  then determined.  The r e s u l t s are g i v e n i n Table  4.  % OMe Batch 2 26.6 t Batch 3 25.7 » Batch 4 *0ne d e t e r m i n a t i o n l o s t .  Yield 4.8 grams 5.8 5.8  0.2  Table 4. M a t e r i a l , from F i r s t M e t h y l a t i o n L i q u o r .  DISCUSSION Before the r e s u l t s are d i s c u s s e d i t would be a d v i s a b l e t o say a few words w i t h r e g a r d t o the methoxyl d e t e r m i n a t i o n s . methoxyl content of the sample i n c r e a s e d i t was o f bromine i n the r e c e i v i n g s o l u t i o n was t h e m e t h y l i o d i d e formed. bromine was  As the  found t h a t the amount  i n s u f f i c i e n t to react with  Low methoxyl v a l u e s r e s u l t e d s i n c e no  p r e s e n t t o r e a c t w i t h the methyl i o d i d e and prevent i t s  escape i n t o the atmosphere.  I t i s t h e r e f o r e recommended t h a t the  amount of bromine i n the r e c e i v e r s be i n c r e a s e d so t h a t the m e t h y l i o d i d e from samples w i t h h i g h methoxyl v a l u e s can be One  of the purposes of t h i s r e s e a r c h was  t o determine i f a  l i n k a g e e x i s t s between the c e l l u l o s e and h e m i c d l u l o s e F o r t h i s r e a s o n h o l o c e l l u l o s e was  methylated.  handled.  fractions.  However, m e t h y l a t i o n  r e q u i r e s an a l k a l i n e medium, so t h a t most o f the h e m i c e l l u l o s e s are e x t r a c t e d d u r i n g the f i r s t m e t h y l a t i o n .  Therefore under the  ex-  p e r i m e n t a l c o n d i t i o n s used i t would be i m p o s s i b l e t o determine ages i n v o l v e d between the two f r a c t i o n s i n h o l o c e l l u l o s e .  As  linka  r e s u l t of the a l k a l i n e c o n d i t i o n s of the r e a c t i o n h e m i c e l l u l o s e s are g r a d u a l l y e x t r a c t e d from the h o l o c e l l u l o s e .  I f linkages d i d exist  between the two f r a c t i o n s they c o u l d n o t be d e t e c t e d s i n c e , b e i n g i n s o l u t i o n , the h e m i c e l l u l o s e s are more s u s c e p t i b l e t o m e t h y l a t i o n so t h a t the h y d r o x y l groups i n v o l v e d i n the l i n k a g e would p r o b a b l y methylated.  be  I n a d d i t i o n w i t h the removal o f the h e m i c e l l u l o s e s , the  19. hydroxyl groups of the alpha-cellulose would be more exposed to the a l k y l a t i n g agents.  Further attempts to e s t a b l i s h the presence of a  cellulose-hemicellulose linkage would require the absence of aqueous solutions since i t has been shown that after the c h l o r i t i n g t r e a t ment small portions of the hemicelluloses could be extracted with water. As a r e s u l t of the methylation the holocellulose was s p l i t i n t o two f r a c t i o n s ; i ) the insoluble residue and i i ) the material soluble  i n the methylation l i q u o r .  The problem now at hand i s t o  determine the composition of these two f r a c t i o n s .  The f i r s t step  required to solve t h i s problem i s to completely methylate each f r a c tion.  Therefore the insoluble residue was methylated, the conditions  being kept approximately the same f o r each run u n t i l a t o t a l of seven methylations had been made.  The methylation was stopped at t h i s point  since no more time was available.  However the methylation curve i s  l e v e l l i n g out at t h i s stage which would indicate that a completely methylated condition had nearly been obtained.  Further methylation  may give a product with a higher methoxyl content but t h i s would be due to extraction of sugar residues with the r e s u l t that more hydroxyl groups would be available f o r methylation. The r e s u l t s i n Table 2 indicate providing experimental cond i t i o n s are not varied, that the methylation proceeds i n stages since approximately the same methoxyl content i s attained i n the various batches after one and two methylations.  Some hydroxyl groups are  more favourably situated than others with the r e s u l t that they are methylated during the f i r s t methylation.  On the second methylation  hydroxyl groups l e s s favourably situated would be methylated and with continued methylation hydroxyl groups even less available would be  20. methylated.  The methoxyl content i n c r e a s e s r a p i d l y a t f i r s t b u t oh  c o n t i n u e d m e t h y l a t i o n remains p r a c t i c a l l y c o n s t a n t .  Free hydroxyl  groups may s t i l l be p r e s e n t i n the methylated m a t e r i a l b u t these groups may be u n a v a i l a b l e t o m e t h y l a t i o n . The It  q u e s t i o n a r i s e s as t o what the i n s o l u b l e r e s i d u e i s .  i s obvious from the methoxyl content o b t a i n e d a f t e r seven  methyla-  t i o n s t h a t the i n s o l u b l e r e s i d u e o b t a i n e d i s n o t c e l l u l o s e s i n c e c e l l u l o s e can be methylated t o a methoxyl content o f 45.6 p e r c e n t . T h i s v a l u e c a n be a t t a i n e d a f t e r three s u c c e s s i v e treatments o f c e l l u l o s e w i t h d i m e t h y l s u l f a t e and c a u s t i c soda ( 2 4 ) . Another p o s s i b i l i t y i s t h a t t h i s m a t e r i a l i s methylated alpha-cellulose.  A t the end o f the seventh m e t h y l a t i o n o f the h o l o -  c e l l u l o s e r e s i d u e the methoxyl c o n t e n t i s 31.5 p e r c e n t .  However  w i t h c o n t i n u e d m e t h y l a t i o n i t may be p o s s i b l e t o reach-the maximum methoxyl c o n t e n t (37.3%) o f S i t k a Spruce a l p h a - c e l l u l o s e as was accomplished by B e l l (25) a f t e r twelve m e t h y l a t i o n s . s o l i d r e s i d u e c o n s i s t s o f methylated  I n t h i s case the  a l p h a - c e l l u l o s e , which g i v e s on  h y d r o l y s i s w i t h methyl a l c o h o l and d r y hydrogen c h l o r i d e a p o r t i o n r e s i s t a n t t o h y d r o l y s i s (OMe 27.8%) and a p o r t i o n which g i v e s 2.3.6. t r i m e t h y l methyl glueoside |*2Ee* s m a l l amount o f d i m e t h y l methyl T  g l u c o s i d e ( 2 5 ) . T h i s l a s t p o r t i o n Besembles c o t t o n c e l l u l o s e . did  f u r t h e r work on the " r e s i s t a n t p o r t i o n " .  He methylated  Bell  this  m a t e r i a l as c o m p l e t e l y as p o s s i b l e and e v e n t u a l l y on h y d r o l y s i s i s o l a t e d v a r i o u s methyl d e r i v a t i v e s o f glucose ( c h i e f l y d i m e t h y l ) . The methoxyl v a l u e s o b t a i n e d from the m e t h y l a t i o n o f h o l o c e l l u l o s e were compared w i t h those from the m e t h y l a t i o n of the e x t r a c t i v e - f r e e spruce.  Although the e x t r a c t i v e - f r e e spruce wood has  a h i g h e r i n i t i a l methoxyl content due t o the presence  of l i g n i n ,  21. which has a methoxyl content o f about 15 p e r c e n t , the h o l o c e l l u l o s e r e s i d u e a c q u i r e s a h i g h e r methoxyl content w i t h succeeding  methylations  s i n c e w i t h the removal o f l i g n i n and h e m i c e l l u l o s e s more h y d r o x y l groups are a v a i l a b l e f o r e t h e r f o r m a t i o n .  The i n c r e a s e d a v a i l a b i l i t y  o f the h y d r o x y l groups i s due n o t o n l y t o severance  of possible l i n k -  ages but t o the removal o f m a t e r i a l which would h i n d e r the p e n e t r a t i o n of the a l k y l a t i n g agents.  However an examination  of Figure 5 reveals  a s i m i l a r i t y between t h e two c u r v e s , which i n d i c a t e s t h a t the h o l o c e l l u l o s e r e s i d u e resembles the o r i g i n a l wood.  I n a d d i t i o n the  m e t h y l a t i o n curve f o r h o l o c e l l u l o s e seems t o be l e v e l l i n g o u t . is  This  an i n d i c a t i o n t h a t complete m e t h y l a t i o n has almost been o b t a i n e d .  F u r t h e r m e t h y l a t i o n may r e s u l t i n a h i g h e r methoxyl content b u t t h i s would be the r e s u l t o f e x t r a c t i o n o f more o f the carbohydrate m a t e r i a l . The  i n s o l u b l e r e s i d u e can t h e r e f o r e be c o n s i d e r e d t o be an i n t e r -  mediate between a l p h a - c e l l u l o s e and the o r i g i n a l wood.  Future work  toward e l u c i d a t i o n o f the s t r u c t u r e o f t h i s r e s i d u e would r e q u i r e h y d r o l y s i s , by use o f methanol and hydrogen c h l o r i d e o f the r e s i d u e and i d e n t i f i c a t i o n o f the methylated  sugars  present.  A p o i n t t o be c o n s i d e r e d i n t h i s i n s t a n c e i s the a d v i s a b i l i t y o f complete m e t h y l a t i o n .  The t o t a l amount o f carbohydrate  m a t e r i a l l o s t i n c r e a s e s w i t h each m e t h y l a t i o n , s i n c e at a c e r t a i n stage i n m e t h y l a t i o n , the methylated  c e l l u l o s e becomes s o l u b l e i n  water and s i n c e h e m i c e l l u l o s e s m a t e r i a l s t i l l r e t a i n e d i n t h i s r e s i d u e w i l l be l o s t w i t h succeeding m e t h y l a t i o n .  As a r e s u l t o f t h i s l o s s  more h y d r o x y l groups are a v a i l a b l e f o r m e t h y l a t i o n .  T h e r e f o r e the  methoxyl value w i l l r i s e a f t e r each s t e p so t h a t a c t u a l l y i t cannot be d e f i n i t e l y e s t a b l i s h e d when m e t h y l a t i o n i s complete.  I t may be ad-  v i s a b l e t o h y d r o l y z e the m a t e r i a l on hand a f t e r each m e t h y l a t i o n step and then determine the methylated  sugar  derivatives.  22. The next matter to be considered i s the material present i n the methylation liquor, which represents about twenty per cent of the o r i g i n a l material.  Two  approaches could be made i n attempts to  i d e n t i f y the various sugar derivatives present.  The p a r t i a l l y methyl-  ated material could be hydrolyzed by treatment with methyl alcohol and dry hydrogen chloride and then the components i d e n t i f i e d or the material could be methylated to completion and then hydrolyzed as above• In either case a complex mixture of methylated sugars w i l l result.  P a r t i t i o n chromatography seems to be the best t o o l available  f o r the i d e n t i f i c a t i o n of the compounds present i n the mixture. Before the methylated sugars can be properly i d e n t i f i e d c e r t a i n data are required:  such as information concerning proper solvents or  developing reagents and detecting reagents as well as information pertaining to the various methylated sugars needed f o r comparison. A great deal of work has been done i n the l a s t decade on the sugars and t h e i r methylated derivatives (26 to 31) so that s u f f i c i e n t data should be present to enable a successful application of the technique.  23 BIBLIOGRAPHY 1.  R i t t e r , Geo. J . , and K u r t h , E . p., Ind. Eng. Chem. 25, 1250-3 (1933) .  2.  Wise, L o u i s E . , Pulp & Paper Mag. Can., 50 Mo. 3 179-86 (1949).  3.  Wise, L o u i s E . , and R a t l i f f , E . K., A n a l . Chem. 19, 459-62 (1947).  4.  Schmidt, E r i c h , and Graumann, E r i c h , B e r . 54 B 1860-73 (1921). C. A. 16, 273.  5.  Schmidt, E r i c h ,  and Duysen, F r a n z , B e r . 54 B 3241-4 (1921).  C. A. 16, 949. 6.  Schmidt, E r i c h , Tang, Yuan C h i , and Jandebauer, Wilhelm, Naturw i s s e n s c h a f t e n 18 734 (1930) C. A. 24, 5334.  7.  Schmidt, E r i c h , Tang, Yuan C h i , and Jandebauer, Wilhelm, C e l l u losechemie 12, 201-12 (1931) C. A. 26, 1772.  8.  Tang, Yuan C h i , and Wang, H s i o h - L i , C e l l u l o s e c h e m i e 16, 57-64 (1935) C. A. 29, 8323.  9.  K u r t h , E . F., and R i t t e r , Geo. J . , J . Am. Chem. S o c . 56, 2720-3 (1934) .  10.  Van Beckum, Wm. G., and R i t t e r , Geo. J . , Paper Trade J . 104 No. 19, 49-50 (1937).  11.  Thomas, Berwyn B., Paper Ind. and Paper World 26 Mo. 10, 1281-4 (1945) C. A. 39, 1982 . 7  12.  Wise, L o u i s E . , Murphy, M., and D'Addieco, A. A., Paper Trade J . , 122 No. 2, 35-43 (1946); Tech. A s s o c . Papers 29 210 (1946).  13.  Jayme, G., C e l l u l o s e c h e m , 20 43-9 (1942) C. A. 37, 7 6 6 .  14.  Wise, L o u i s E . , | h d ^ B n g i ^ C h e i u • A h a l V 'Edi. 17, 63-4 (1945).  15.  P u r d i e , T., and I r v i n e , J . C , J . Chem. Soc. 1021 (1903).  ?  24. 16.  Denham, W. S., and Woodhouse, H., J . Chem. Soc. 103, 1735-42 (1913).  17.  Denham, W. S., J . Chem. Soc. 119, 77-81 (1921).  18.  Haworth, W. N., J . Chem. Soc. 107, 8-16 (1915).  19.  Irvine, J . C , and H i r s t , E. L., J . Chem. Soc. 121, 1585 (1922).  20.  Irvine, J . C , and H i r s t , E . L., J . Chem. Soc. 123, 518-32 (1923).  2,1.  Haworth, W. N., H i r s t , E . L., and Thomas, H. A., J . Chem. Soc. 821, (1931).  22.  Clark, E . P., J . Assoc. O f f i c i a l Agr. Chem. 15, 136-40 (1932).  23.  Clark, E . P., Ind. and Eng. Chem. A n a l y t i c a l E d i t i o n 10, 677 (1938).  24.  Wise, Louis E., Wood Chemistry (1946) Page 235.  25.  B e l l , David J . , Biochem. J . 26, 590-7 (1932).  26.  B e l l , D. J . , Ann. Rev. Biochem. 18, 87-96 (1949).  27.  Brown, F., H i r s t , E. L., Hough, L., Jones, J . K. N., and Wadman, W. H., Nature 161, 720 (1948).  28.  Hough, L., Jones, J . K. 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