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Fixation mechanism of ammoniacal copper wood preservatives Xie, Changshi 1994

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F I X A T I O N M E C H A N I S M  O F A M M O N I A C A L  C O P P E R  W O O D P R E S E R V A T I V E S b y C H A N G S H I X I E B.Sc. and M . S c . Nanjing University, P. R. of China, A T H E S I S  S U B M I T T E D  I N P A R T I A L  F U L F I L L M E N T  T H E R E Q U I R E M E N T F O R T H E D E G R E E M A S T E R  O F  O F  S C I E N C E  in F A C U L T Y  O F G R A D U A T E  S T U D I E S  (Department of W o o d  Science)  W e accept this thesis as c o n f o r m i n g to the required standard  T H E U N I V E R S I T Y O F B R I T I S H December, ©  1994  Changshi Xie,  1994  C O L U M B I A  1982 O F  In presenting this thesis in partial fulfilment  of the requirements for an advanced  degree at the University of British Columbia, I agree that the Library shall make it freely available for reference and study. I further agree that permission for extensive copying of this thesis for scholarly purposes may be granted by the head of my department  or  by his or  her  representatives.  It  is understood that  copying or  publication of this thesis for financial gain shall not be allowed without my written permission.  Department of The University of British Columbia Vancouver, Canada Date  DE-6 (2/88)  ABSTRACT T h i s thesis describes the first c o m p r e h e n s i v e study o f the c h e m i s t r y o f a m m o n i a c a l copper based w o o d preservatives, including the fixation o f copper a n d nitrogen in treated w o o d ; a n d the identification o f the cause o f the black color in treated Douglas-fir heartwood. T h e effects o f enhanced nitrogen content in a m m o n i a c a l copper solution treated w o o d o n the decay b y three rotting fungi w e r e  investigated.  Taxifolin, a Douglas-fir heartwood extractive was isolated a n d identified using ultraviolet ( U V ) , infrared (IR), nuclear magnetic resonance ( N M R ) a n d s p e c t r o m e t r y ( M S ) . It w a s c o n f i r m e d t h a t t a x i f o l i n r e a c t e d w i t h c o p p e r solutions to f o r m a b l a c k copper-nitrogen-taxifolin  mass  ammoniacal  complex.  Nitrogen fixation in a m m o n i u m hydroxide treated w o o d w a s studied through the r e a c t i o n o f a m m o n i u m h y d r o x i d e s o l u t i o n w i t h w o o d a n d its c o m p o n e n t s . It  was  f o u n d that carbonyl a n d carboxylic groups i n lignin a n d hemicelluloses c a n react w i t h a m m o n i a to fix nitrogen i n w o o d .  T h e fixation m e c h a n i s m of copper and nitrogen in ammoniacal copper  treated  w o o d was studied through the reaction o f vanillin, a lignin m o d e l c o m p o u n d , an a m m o n i a c a l copper solution. T h e green copper c o m p l e x f o r m e d  with  was  extensively studied using infrared (IR), electron spin resonance ( E S R )  elemental  analysis a n d X-ray single crystallography a n d identified to b e a vanillin-copper a m m o n i a complex. A n X-ray structural analysis o f a single crystal o f the  complex  e n a b l e d the structure to b e k n o w n . I n the c o m p l e x b o t h the m e t h o x y a n d  phenolic  o x y g e n a t o m s o f g u a i a c y l units w e r e c o o r d i n a t e d to the copper, together w i t h  ii  nitrogen f r o m a m m o n i a forming asix coordinated complex. This w a s  first  deterrriination o f acrystal structure o f copper-lignin m o d e l c o m p l e x w h i c h  m a y  describe important b o n d formations occurring during the fixation o f copper  and  nitrogen from ammoniacal copper w o o d  preservatives.  T h e effect o f enhanced nitrogen in a m m o n i a c a l copper treated w o o d o n the was studied. W o o d  treated with higher concentrations of a m m o n i u m  s o l u t i o n s h o w e d a n i n c r e a s e d d e c a y r e s i s t a n c e t o b o t h P. placenta e n h a n c e d r e s i s t a n c e t o T. versicolor  decay  hydroxide  a n d a slightly  f u n g u s . H o w e v e r , f o r G. trabeum  the  weight  losses of the a m m o n i u m hydroxide treated-wood was slightly increased relative the control. A m m o n i a c a l copper treated w o o d with l o w copper retention i n c r e a s e d d e c a y r e s i s t a n c e t o b o t h T. versicolor  a n d G. trabeum.  showed  T h e nitrogen in  the c o m p l e x c a n not be used b y fungi for their growth. H o w e v e r , the  ammoniacal  c o p p e r t r e a t e d w o o d w i t h l o w c o p p e r r e t e n t i o n w a s e a s i l y a t t a c k e d b y P. d u e to its a b i l i t y to f o r m i n s o l u b l e c o p p e r o x a l a t e i n c o p p e r t r e a t e d  iii  to  wood.  placenta  T A B L E  O F  C O N T E N T S  page A B S T R A C T  ii  T A B L E  iv  O F C O N T E N T S  L I S T O F T A B L E S  v i i i  LIST O F FIGURES  x  A C K N O W L E D G E M E N T  1.  2.  .  xii  I n t r o d u c t i o n  1  1.1  B l a c k color o f Douglas-fir h e a r t w o o d after treatment w i t h A C A  2  1.2  Fixation m e c h a n i s m of ammoniacal copper preservatives in w o o d  3  1.3  Impact of nitrogen retention in A C A treated w o o d  4  1.4  T h e objectives o f this study  5  B a c k g r o u n d  6  2.1  C h e m i c a l nature of w o o d  6  2.2  Biological deterioration of w o o d  7  2.3  A m m o n i a c a l copper preservatives  8  2.3.1  Role of a m m o n i a in improving preservative treatment  12  2.3.2  A m m o n i a c a l copper complexes  13  2.3.3  Reaction of a m m o n i a and ammoniacal copper w i t h w o o d a n d its c o m p o n e n t s  iv  J. solution  14  2.3.3.1  Reaction of a m m o n i a with w o o d components  14  2.3.3.2  Reaction of ammoniacal copper complex with cellulose.  15  2.3.4  Fixation of ammoniacal copper preservatives in wood.  2.3.5  E S R spectral analysis of w o o d treated with  16  ammoniacal  copper preservatives  2.4  2.5  .0  17  2.3.5.1  T h e principle of ESR.!...  17  2.3.5.2  E S R analysis of a m m o n i a c a l copper treated w o o d  19  E n h a n c e d nitrogen content in a m m o n i a c a l copper treated w o o d  23  2.4.1  Nitrogen requirement for fungal growth  23  2.4.2  Nitrogen content in a m m o n i a c a l copper treated w o o d  24  Black discoloration of Douglas-fir heartwood treated  with  ammoniacal copper preservatives  27  2.5.1  Importance of Douglas-fir w o o d species in B . C . Province  27  2.5.2  Treatability of Douglas-fir  27  2.5.3  Extractive chemistry of Douglas-fir  28  2.5.4  Effect o f the extractives o n w o o d properties  32  E x p e r i m e n t a l  3.1  34  Study o f extractives in Douglas-fir heartwood responsible development o f black discoloration w h e n treating with  for  ammoniacal  copper solution  34  3.1.1  Preliminary analysis of extractives  34  3.1.2  Isolation a n d identification o f the extractive reacting a m m o n i a c a l c o p p e r solution to p r o d u c e a b l a c k color  with 37  3.1.2.1  Isolation o f the extractives  37  3.1.2.2  Identification o f the isolated c o m p o u n d  40  3.1.2.2 3.2  3.3  Reactivity with copper solutions  4  1  Fixation chemistry of ammoniacal copper preservatives  4  2  3.2.1  Sample preparation  4  2  3.2.2  Sample treatment  4  4  3.2.3  Analysis methods  4  5  Nitrogen content in the a m m o n i a c a l copper treated w o o d  5  0  3.3.1  Sample preparation  5  0  3.3.2  Analysis of copper a n d nitrogen in treated blocks  5  1  3.3.3  Fungal exposure of tested block samples  .....52  Results and discussion  4.1  5  Study of extractives in Douglas-fir heartwood responsible development of black discoloration w h e n  tieating  with  for  ammoniacal  copper solution 4.1.1  5  Identification o f the extractive reacting with a m m o n i a c a l s o l u t i o n t o p r o d u c e ab l a c k c o l o r  6  copper 5  6  6  6  Fixation chemistry of ammoniacal copper preservative system  7  2  4.2.1  Reaction of a m m o n i u m hydroxide solution  7  2  4.2.1.1  W o o d  7  2  4.2.1.2  Cellulose  7  4  4.2.1.3  Holocellulose  7  4  4.2.1.4  Lignin  7  5  7  8  4.1.2  T h e nature of the chemical c o m p l e x  formed  between copper solution and taxifolin 4.2  6  4.2.2  Reaction of ammoniacal copper solution with w o o d  4.2.3  Reaction of a m m o n i u m hydroxide / ammoniacal vi  copper solution with a lignin m o d e l c o m p o u n d 4.2.3.1  79  Reaction of vanillin with a a m m o n i u m hydroxide solution  4.2.3.2 4.3  79  Reaction of vanillin with ammoniacal copper solution.. 82  W h e t h e r the enrichment of nitrogen in  ammoniacal-copper  preservative treated w o o d increases the d e c a y potential  100  4.3.1  W o o d treated with a m m o n i u m hydroxide solution  100  4.3.2  W o o d treated with a m m o n i u m hydroxide solution  104  5 .  C o n c l u s i o n  6.  R  7.  L i t e r a t u r e  e  c  o  109 m  m  e  n  d  a  t  i  o  n  ill 113  vii  L I S T O F  T A B L E S  2-1-1  Composition of A C A  11  2-1-2  T h e s u c c e s s i v e f o r m a t i o n c o n s t a n t f o r t h e c o p p e r (II) a n d n i c k e l (II) ions w i t h a m m o n i a as a l i g a n d  13  2- 1-3  C h e m i c a l composition o f six c o m m o n coniferous w o o d s  31  3 - 1-1  Crystallographic data  48  4- 1-1  A s s i g n m e n t o f absorption bands in I R spectrum o f the c o m p o u n d  4-1-2  C h e m i c a l shifts for the p r o t o n N M R s p e c t r u m o f the  isolated 60 c o m p o u n d  extracted from Douglas-fir heartwood  62  4-2-1  P e a k area ratio o f amide/salt against c a r b o n - h y d r o g e n sfretcliing  74  4-2-2  A t o m i c coordinates and B e q  85  4-2-3  Selected b o n d lengths (A) for vanillin-copper-ammonia complex  86  4-2-4  Selected b o n d angles (°) for vanillin-copper-ammonia complex  87  4-2-5  H y d r o g e n bonds and C - H  88  4-2-6  Assignment of m a i n absorption bands in I R spectra of vanillin and  4-2-7  4-3-1  4-3-2  0 interaction  copper-vanillin complex  93  T h e E S R parameters for copper-vanillin complex and copper solution a n d c o p p e r treated w o o d at r o o m t e m p e r a t u r e  97  N i t r o g e n content in the treated w o o d a n d p H values o f the solution  leachate  C o p p e r a n d nitrogen contents a n d weight losses o f the treated e x p o s e d t o P. placenta.  ,  viii  102 w o o d 107  4-3-2  C o p p e r a n d nitrogen contents a n d weight losses o f the treated e x p o s e d t o G. trabeum  4-3-3  ....  w o o d  '.  C o p p e r a n d nitrogen contents a n d weight losses o f the treated e x p o s e d t o T. versicolor  1 0 7  w o o d 1 0 7  ix  L I S T O F  2-1-1  2- 1-2  F I G U R E S  E n e r g y levels for a system with electron spin S=l/2 and nuclear 1=3/2 s h o w i n g the effects of magnetic field a n d the nuclear quadrupole m o m e n t R e l a t i o n b e t w e e n t h e m a g n e t i c p a r a m e t e r s g// a n d A / / f o r  spin 21  copper-treated  w o o d and copper solutions.  22  3- 1-1  Preliminary extraction procedure for isolation of extraneous c o m p o u n d s  4- 1-1  U V absorption s p e c t r u m o f a m e t h a n o l solution ( l x 10" ) o f the solid isolated f r o m acetone-extractive  4-1-2  4-1-3  5  white 58  F T I R spectra o f a) taxifolin f o r m a c e t o n e extractive, b) the b l a c k precipitate f o r m e d during the reaction o f taxifolin a n d a m m o n i a c a l copper solution  59  iH-NMR spectrum o f the white solid isolated f r o m in acetone-D  61  acetone-extractive  6  4-1-4  4-1-5  4-1-6  4-1-7  4-1-8  4-2-1  ..36  M a s s spectrum of the white solid isolated f r o m acetone from Douglas-fir Diagnostic m a s s spectral fragmentation f r o m the white extracted f r o m Douglas-fir heartwood  extract 63 solid 64  T h e m o l e c u l a r structure o f t a x i f o l i n (a) a n d the three p o s s i b l e 1:1 c o p p e r c o m p l e x e s s h o w i n g t h e t h r e e r e a c t i v e (b), (c) a n d (d) C h a n g e s i n the visible spectra o f taxifolin i n m e t h a n o l to w h i c h added a ammoniacal copper solution  65 was 67  T h e visible spectra o f taxifolin plus a) C C A solution, b) c o p p e r i n excess s o d i u m sulphate h y d r o x i d e , c) c o p p e r sulphate i n distilled w a t e r a n d d) 2 % a m m o n i u m h y d r o x i d e solution, 60 minutes after m i x i n g  68  I R s p e c t r a o f w o o d s a m p l e s b e f o r e (a) a n d after (b) t r e a t m e n t a m m o n i u m hydroxide solution  73  X  with  4-2-2  4-2-3  4-2-4  4-2-5  4-2-6  4-2-7  I R spectra o f holocellulose before a n d after a m m o n i u m h y d r o x i d e treatment  76  I R spectrum o f the solid obtained hydroxide treated holocellulose  77  from  the filtrate o f a m m o n i u m  GC-MS spectrum o f the reaction products o f vanillin with a m m o n i u m hydroxide  80  Perspective v i e w o f Cu(II)-bis(vanillinato)bis(ammonia) with the atomic numbering; 3 3 % probability thermal ellipsode are s h o w n for the n o n - h y d r o g e n atoms  84  Packing of Cu(II)-bis(vanillinato)bis(ammonia) in a monoclinic unit cell. T h e h y d r o g e n b o n d s are indicated b y thin lines  89  I R spectra o f vanillin a n d v a n i l l i n - c o p p e r c o m p l e x , a) vanillin, b) vanillin-copper complex  91  4-2-8  UV-visible spectrum o f a N u j o l m u l l o f the vanillin-copper c o m p l e x  92  4-2-9  E S R spectra o f v a n i l l i n - c o p p e r c o m p l e x , a) solid at r o o m b) in DMSO  solution at 1 1 5 K  temperature 96  4-3-1  W e i g h t losses for a m m o n i u m hydroxide treated w o o d  103  4-3-2  W e i g h t losses for a m m o n i a c a l copper treated w o o d  108  xi  A C K N O W L E D G E M E N T S  I w o u l d like to sincerely thank D r . J o h n N . R . R u d d i c k , m y supervisor, his patient guidance a n d encouragement throughout the course o f the w o r k a n d i n preparation o f this  for  research  thesis.  I w o u l d like to express m y appreciation to the m e m b e r s o f m y  thesis  committee, D r . L . Paszner, D r . G . H e r r i n g a n d D r . N . R i c h a r d s o n for their invaluable advice a n d support o n several aspects o f this I gratefully acknowledge the NSERC/Industrial  thesis. Chair in W o o d  preservation  for financial support. Finally, I w i s h to sincerely t h a n k m y wife Y i F e n g a n d m y s o n L e i for their patience a n d understanding over the past years.  xii  1  1.  I  N  T  R  O  D  U  C  T  I  O  W o o d is ar e m a r k a b l e m a t e r i a l o f g r e a t v a l u e a n d i m p o r t a n c e i n t h e  world  e c o n o m y . C a n a d a is the w o r l d ' s l e a d i n g e x p o r t e r o f forest p r o d u c t s . I n  1991  C a n a d i a n exports o f forest p r o d u c t s w e r e v a l u e d at $ 1 9 , 1 0 0 m i l l i o n . W i t h a trade s u r p l u s o f $ 1 8 . 1 b i l l i o n i n 1 9 9 1 , t h e f o r e s t i n d u s t r y w a s am a j o r c o n t r i b u t o r t o Canada's positive trade balance ( C a n a d a Y e a r B o o k , 1994). Clearly, the i n d u s t r y p l a y s am a j o r r o l e i n C a n a d a ' s e c o n o m i c  forest  activity.  W o o d is u s e d e x t e n s i v e l y as astructural m a t e r i a l i n the w o r l d . W h e n  w o o d  m a t e r i a l is i n u s e u n d e r c o n d i t i o n s w h e r e it b e c o m e s w e t , it is l i a b l e to d e c a y . has b e e n estimated that the a n n u a l loss i n C a n a d a due to the biological  It  destruction  o f t i m b e r is i n e x c e s s o f $ 5 0 0 m i l l i o n . D e c a y o f d o m e s t i c d w e l l i n g s a l o n e h a s  been  estimated to cost C a n a d i a n h o m e o w n e r s over $ 1 0 0 m i l l i o n a n n u a l l y ( R u d d i c k , 1980a). W i t h the p o p u l a t i o n i n C a n a d a continuing to increase, the d e m a n d w o o d s u p p l y w i l l continue to g r o w . O n e strategy designed to achieve a n s u p p l y o f w o o d f o r this g r o w t h is to i n c r e a s e the service life o f w o o d subject to d e c a y . C o n s e q u e n t l y , m o r e attention is b e i n g f o c u s e d o n  for adequate  products w o o d  preservation, since this c a n help conserve forests a n d provide e c o n o m i c a n d benefits (Wilkinson,  social  1979).  T h e vacuum-pressure impregnation of w o o d e n commodities preservatives, to e x t e n d their service life, has b e e n v e r y successful i n  with expanding  the use o f n o n d u r a b l e w o o d species s u c h as h e m - f i r [a c o m m e r c i a l m i x t u r e  of  w e s t e r n h e m l o c k (Tsuga heterophylla S a r g e . ) a n d a m a b i l i s f i r {Abies amabilis Forbes.)]. In C a n a d a the w o o d preservation industry treats 1.985 m i l l i o n cubic m e t e r s ( m ) o f w o o d e a c h year, w i t h 5 1 . 5 % g o i n g to c o n s u m e r l u m b e r , 2 1 . 3 % 3  pole p r o d u c t i o n a n d 2 4 . 1 % to industrial l u m b e r . T h e 1992 value o f this treated  to  N  2  l u m b e r w a s $ 5 4 7 million. T h e value o f the total v o l u m e o f treated w o o d  installed  i n C a n a d a i s i n e x c e s s o f $ 1 0 b i l l i o n ( S t e p h e n s et al, 1 9 9 4 ) . A m o n g t h e  w o o d  preservatives used in Canada, chromated-copper-arsenate (CCA),  a major  w a t e r b o r n e c h e m i c a l preservative, is w i d e l y u s e d to p r o t e c t the w o o d . H o w e v e r , i s r a r e l y u s e d f o r D o u g l a s - f i r {Pseudotsuga menziesii ( M i r b . ) F r a n c o ) o r  it  spruce  (Picea s p . ) h e a r t w o o d b e c a u s e o f p o o r p e n e t r a t i o n . Improved treatment of such refractory w o o d species can be achieved  b y  a m m o n i a c a l copper based w o o d preservatives. R u d d i c k (1980b) investigated  the  t r e a t a b i l i t y o f l o d g e p o l e p i n e (Pinus contorta D o u g l . ) h e a r t w o o d w i t h  ammoniacal  copper arsenate ( A C A ) and C C A .Analysis of preservative penetration  and  retention s h o w e d that both w e r e higher in the A C A treated l u m b e r than in that treated with C C A .H o w e v e r , with s o m e w o o d species with A C A treatment in an unpleasant dark color (Ruddick, 1979). This color reduces the  results  acceptability  o f c e r t a i n p r o d u c t s , e.g. d e c k i n g a n d f e n c i n g . In the formulations o f a m m o n i a c a l copper preservative system  developed,  c o p p e r is the b i o c i d e l y active c o m p o n e n t , b u t o t h e r c o - b i o c i d e s a r e a l s o i n c l u d e d , s u c h as arsenic i n A C A . Industrial c o n c e r n w i t h the toxicity a n d the cost o f arsenic (V) oxide has led to the replacement o f s o m e arsenic w i t h less toxic zinc i n the development of ammoniacal copper zinc arsenate (ACZA).  More  recently,  a m m o n i a c a l copper/quat ( A C Q ) a n d a m m o n i a c a l c o p p e r citrate ( C C ) h a v e commercialized. T h e y exhibit relatively l o w m a m m a l i a n toxicity a n d  been  l o w  environmental impact.  1.1  Black color of Douglas-fir heartwood after treatment with  ACA  It is w e l l k n o w n t h a t t h e A C A t r e a t m e n t o f c e r t a i n w o o d s p e c i e s , s u c h  as  D o u g l a s - f i r , results i n ad a r k e n i n g o f the w o o d d u r i n g treatment. T h e c a u s e o f this  3  d a r k e n i n g is m o s t l i k e l y r e l a t e d to a m m o n i u m h y d r o x i d e i n the p r e s e r v a t i v e s ,  since  treatment w i t h either copper or arsenic containing preservatives s u c h as C C A , does n o t g i v e t h i s r e a c t i o n . It m a y a l s o b e af u n c t i o n o f t h e h i g h p H o f t h e  treating  solution. Aliterature survey c o n f i r m e d that n o explanation has yet b e e n f o u n d for this d a r k e n i n g o f Douglas-fir after treatment w i t h a m m o n i a c a l  copper  p r e s e r v a t i v e s . It is n o t e v e n k n o w n , f o r e x a m p l e , w h i c h c o m p o n e n t i n D o u g l a s - f i r h e a r t w o o d is r e s p o n s i b l e f o r the d a r k c o l o r .  1.2  Fixation of ammoniacal copper preservative in wood T h e f i x a t i o n m e c h a n i s m o f a m m o n i a c a l c o p p e r preservatives is  not  u n d e r s t o o d . It h a s b e e n s u g g e s t e d t h a t t h e c u p r i a m m o n i u m i o n s i n s o l u t i o n  react  b y ion exchange with exchangeable protons in functional groups in wood, such c a r b o x y l i c a c i d g r o u p s ( K u p c h i n o v et al.,  1975). In addition, evaporation  as  of  a m m o n i a will result in the b r e a k d o w n o f the tetraminocupric complexes present  in  solution, thus f o r m i n g water-insoluble c o p p e r salts, s u c h as arsenate i n the c a s e  of  ACA  (Hartford, 1973). T o date, this p r o p o s e d fixation m e c h a n i s m has not  verified  been  experimentally.  R e c e n t l y , this h y p o t h e s i s w a s c h a l l e n g e d w h e n it w a s o b s e r v e d that A C A treated spruce poles retained the enhanced nitrogen levels, m o r e than two  years  a f t e r t r e a t m e n t . T h e n i t r o g e n m u s t t h e r e f o r e b e s t r o n g l y b o u n d i n t h e w o o d . It is possible that the a m m o n i a m a y react with the w o o d components i m p r e g n a t i o n , a l l o w i n g the nitrogen to b e fixed to the  during  wood.  A n u m b e r o f investigations o f the b o n d i n g o f copper c o m p l e x e s i n treated w o o d u s i n g e l e c t r o n s p i n r e s o n a n c e ( E S R ) h a v e b e e n r e p o r t e d ( R u d d i c k et al., 1 9 9 2 ; H u g h e s et al, 1 9 9 2 ) . I t w a s f o u n d t h a t c o p p e r - n i t r o g e n c o m p l e x e s w e r e  most  likely f o r m e d in a m m o n i a c a l copper treated wood. These complexes h a d a high  4  l e a c h i n g r e s i s t a n c e . B a s e d o n t h e a b o v e o b s e r v a t i o n s , ar e a c t i o n b e t w e e n  the  a m m o n i a a n d the copper in the preservative or the w o o d m a y be proposed results i n ac o m p l e x f o r m a t i o n , a n d b o u n d n i t r o g e n p r e s e n t i n treated  w h i c h  wood.  H o w e v e r , the f o r m o f this nitrogen fixed i n the w o o d a n d the nature o f the  copper-  nitrogen complexes in treated w o o d remain u n k n o w n .  1.3  The impact of nitrogen retention in ACA-treated wood T h e m a i n organisms responsible for deterioration o f w o o d are bacteria,  fungi a n d insects. In temperate regions o f Canada, the m o s t abundant significant organisms responsible for w o o d decay are fungi. Fungi, like  and other  organisms, require substantial amounts of nitrogen for synthesis o f protein a n d other cell constituents or p r o d u c t s s u c h as nucleoproteins, lipoproteins,  enzymes,  a n d chitin i n h y p h a l cell walls. W o o d - i n h a b i t i n g fungi are u n i q u e i n their ability to obtain their nitrogen needs f r o m the generally very small a m o u n t available in w o o d . T h e n i t r o g e n c o n t e n t o f w o o d r a n g e s f r o m 0.03 %a n d 0.1 %o f the  dry  w e i g h t o f w o o d ( A l l i s o n et al., 1 9 6 3 , C o w l i n g a n d M e r r i l l , 1 9 6 6 ) . M a n y f u n g i a r e able to use a m m o n i a , nitrates, nitrites, a n d u r e a as sole sources o f nitrogen.  Several  researchers have s h o w n that increasing the nitrogen content o f w o o d , frequently a d d i t i o n o f a n a m m o n i u m salt, i n c r e a s e s the rate o f d e c a y b y  b y  wood-destroying  f u n g i . A m m o n i u m is o f t e n the b e s t n i t r o g e n s o u r c e , b u t it m a y a f f e c t the m e d i a  p H  and, hence, growth responses (Zabel and Morrell, 1992). It w a s f o u n d t h a t t h e n i t r o g e n c o n t e n t i n A C A - t r e a t e d s p r u c e w o o d  was  m u c h higher than that i n untreated w o o d e v e n after t w o years o f outdoor storage.  It  w a s suggested that the nitrogen w a s strongly b o u n d in the w o o d . W h e t h e r fungi or bacteria are capable o f metabolizing the higher nitrogen content in the treated w o o d to p r o m o t e their g r o w t h is u n k n o w n .  a m m o n i a -  5  1.4  The  objectives of this study  B a s e d u p o n the limited knowledge o f the reactions o f a m m o n i a c a l solutions with w o o d , a n d the possible enhanced effect o f the a m m o n i a  copper  treatment  o n fungal activity, the following studies have b e e n planned.  (1) Determine the cause of the treated with  darkening of Douglas-fir heartwood when  ACA.  (2) Investigate the fixation mechanism of ammoniacal copper complexes in wood and  determine which wood component can  take part in the fixation  reaction.  (3) Establish whether enrichment of nitrogen in ammoniacal-copper preservative treated wood increases the decay potential.  6  2.  2.1  B  A  C  h  e  C  m  i  K  c  a  G  ln  a  R  t  u  O  r  eo  U  fw  N  o  o  D  d  W o o d is c o m p r i s e d p r i m a r i l y o f c e l l u l o s e ( 4 0 - 5 0 % ) a n d h e m i c e l l u l o s e 3 5 % ) a n d l i g n i n ( 1 5 - 3 5 % ) . T h e r e is a m i n o r a m o u n t o f e x t r a n e o u s m a t e r i a l s  (20(2-  10%) i n w o o d , m o s t l y i n the f o r m o f organic extractives s u c h as tannins, lignan, flavonoids, stilbenes, terpenoid, starch, lipids, pectins, alkaloids, proteins, fat a n d w a x e s a n d as w e l l as trace a m o u n t o f i n o r g a n i c m i n e r a l s  (0.1-1.0%).  C e l l u l o s e is the m o s t i m p o r t a n t c o m p o n e n t i n w o o d a n d it c o n s i s t s o f 1,4-|3linked glucopyranose sugar units having both intermolecular a n d intramolecular hydrogen bonding. T h e average cellulose chain length (or degree  of  p o l y m e r i z a t i o n ) is i n the 7 , 0 0 0 to 1 0 , 0 0 0 g l u c o s e u n i t r a n g e . C e l l u l o s e consists  of  a crystalline area where cellulose chains are arranged in an orderly three d i m e n s i o n a l crystal lattice as w e l l as a m o r p h o u s regions w h e r e the  cellulose  chains s h o w m u c h less orientation w i t h respect to e a c h other. T h e surfaces o f the microfibrils are surrounded b y hemicellulose. T h e hemicellulose a n d lignin are associated primarily w i t h the noncrystalline zones that occur within a n d  between  the microfibrils. Hemicelluloses are p o l y m e r s o f various pentose a n d h e x o s e sugar units. T h e m a j o r sugars in the p o l y m e r backbones are glucose, xylose,  mannose,  galactose, arabinose, rhamnose, a n d uronic acids. T h e chemistry o f  hemicelluloses  has b e e n w i d e l y studied, a n d has b e e n f o u n d to b e m u c h m o r e c o m p l e x  than  cellulose. Hemicelluloses differ f r o m cellulose in having short chain lengths,  and  side chains that are sometimes branched, a n d sugar m o n o m e r s other than glucose. Hemicellulose are either water or alkali soluble. In softwoods  the  galactoglucomannans and arabinoglucuronxylans predominate, while  in  7  h a r d w o o d s the arabinoglucuronoxylans a n d glucomannans are the m o s t occurring  frequently  structures.  T h e t h i r d m a j o r w o o d c o m p o n e n t , l i g n i n , is ar a n d o m t h r e e  dimensional  p o l y m e r o f two basic phenylpropane monomers. T h e phenypropane units  are  linked b y biphenyl, aryl-alkyl or ether linkages, a n d f o r m relatively stable  and  inactive p o l y m e r s that are resistant to hydrolysis. Lignin c a n be d i v i d e d into several classes according to the structural elements. G u a i a c y l lignin, w h i c h  occurs  i n a l m o s t a l l s o f t w o o d s , i s l a r g e l y ap o l y m e r i z a t i o n p r o d u c t o f c o n i f e r y l a l c o h o l . T h e g u a i a c y l - s y r i n g y l lignin, t y p i c a l o f h a r d w o o d s , is ac o p o l y m e r o f c o n i f e r y l a n d s i n a p y l a l c o h o l s , the ratio v a r y i n g f r o m 4:1 to 1:2 f o r the t w o  m o n o m e r i c  units. T h e c o n c e n t r a t i o n o f l i g n i n is h i g h e r i n the m i d d l e l a m e l l a t h a n i n the s e c o n d a r y w a l l . H o w e v e r , b e c a u s e o f the thickness o f the s e c o n d a r y w a l l , at least 7 0 % o f the l i g n i n i n s o f t w o o d s is l o c a t e d i n this r e g i o n . L i g n i n p r o v i d e s a n d strength. Lignin  stiffness  a l s o is av e r y d u r a b l e m a t e r i a l , a c t i n g as ab a r r i e r a g a i n s t  microbial attack o f the m o r e vulnerable carbohydrates in the cell wall. L i g n i n h a s b e e n p r o v e d t o b e am a j o r f i x a t i o n site f o r s o m e i n o r g a n i c preservative c o m p o n e n t s , s u c h as c o p p e r (Dahlgren, 1975). T h e a m o u n t , type location o f lignin w i t h i n the w o o d structure h a v e asignificant i m p a c t o n  and  the  fixation o f w o o d preservatives a n d thus the microbial susceptibility o f the  2.2  w o o d  wood.  Biological deterioration of wood W o o d , a s an a t u r a l l y p r o d u c e d o r g a n i c m a t e r i a l , m a y b e s u b j e c t t o  T h e principal agencies o f this destruction are bacteria, fungi a n d insects.  decay, In  general, the m a i n agencies o f biodeterioration o f w o o d in C a n a d a are fungi. N o t all fungi that colonize w o o d lead to degradation o f the structural c o m p o n e n t s ( / . e. d e c a y ) . S u c h m o u l d a n d s t a i n f u n g i g e n e r a l l y d o n o t c a u s e l o s s i n  8  strength. D e c a y fungi cause significant softening or w e a k e n i n g o f w o o d , often  to  the point that w o o d physical characteristics are completely destroyed. D e c a y  fungi  c a n be further classified as b r o w n rots a n d w h i t e rots (Nicholas, 1973; Z a b l e  and  Morrell, 1992). T h e b r o w n rots selectively attack the cellulose a n d o f the cell, w i t h little effect o n the l i g n i n ( B r a y a n d A n d r e w s , 1 9 2 4 ;  hemicellulose Campbell,  1952). W o o d seriously degraded b y these fungi will have an abnormally brownish color. W h i t e rot f u n g i h a v e the ability to degrade b o t h the lignin a n d  cellulose  components o f the cell (Kawase, 1962). T h e y sometimes have only a limited effect u p o n the c o l o r o f the w o o d b u t i n o t h e r c a s e s m a y g i v e it a b l e a c h e d o r w h i t i s h color. Soft-rot f u n g i are A s c o m y c o t i n a that attack w o o d that is v e r y w e t ( 8 0 - 1 0 0 MC)  and usually penetrate rather slowly. T h e y gradually degrade w o o d f r o m  %  the  surface. T h e y are similar to b r o w n rot f u n g i i n that o n l y degrade cellulose ( Z a b l e and Morrell,  2 . 3  1992).  A m m o n i a c a l  c o p p e r p r e s e r v a t i v e s  A m m o m a c a l w o o d preservatives have b e e n k n o w n since the beginning the century. In 1907 " A c z o l " w a s o n e o f the first to b e i n t r o d u c e d as  of  an  a m m o m a c a l solution o f c o p p e r a n d zinc salts w i t h p h e n o l ( H u n t a n d G a r r a t t , 1 9 6 7 ) . I n 1 9 4 0 the U n i v e r s i t y o f C a l i f o r n i ap a t e n t e d a n a m m o n i a c a l preservative called Chemonite®  w o o d  ( G o r d o n , 1940), w h i c h c o n t a i n e d c o p p e r salts to  p r o v i d e fungicidal action, a n d arsenic salts w h i c h f u n c t i o n e d as a fungicide as as a n insecticide. T h e salts w e r e dissolved i n a q u e o u s a m m o n i a a n d  the  preservative was fixed in the w o o d b y the precipitation o f water-insoluble a r s e n a t e as t h e v o l a t i l e a m m o n i a e v a p o r a t e d . It w a s first a m m o n i a c a l arsenite preservative ( A C A ) w h i c h w a s submitted to the A W P A  well  copper  copper  preservatives  c o m m i t t e e i n 1949 (Baechler, 1949): T h e first c o m m e r c i a l C h e m o n i t e ®  treating  9  plant w a s built i n 1935 to p r e s e r v e l u m b e r , ties, poles, a n d piles, m a i n l y o f w h i t e fir.Later in 1941, a Chemonite®  treating plant w a s built that processed  exclusively coastal Douglas-fir (Fritz,  almost  1947).  T h e c o m p o s i t i o n o f A C A is s h o w n i n table 2 - 1 - 1 . A C A w a s  originally  p r e p a r e d at the treating p l a n t b y m i x i n g the c o p p e r c h e m i c a l w i t h arsenic  trioxide  i n a m m o n i u m h y d r o x i d e , w h i c h w a s k n o w n as a m m o n i a c a l c o p p e r arsenite. In the m i d - 1 9 7 0 ' s , it w a s r e a l i z e d that d u r i n g the m i x i n g p r o c e s s , t h e a i r o x i d i z e d  the  arsenic to the pentavalent form. T h u s the n a m e w a s c h a n g e d to a m m o n i a c a l  copper  arsenate (Ruddick, 1982). F o l l o w i n g impregnation o f the A C A in the w o o d ,  the  a m m o n i a evaporates. This causes a b r e a k d o w n o f the chemical complexes  and  formation o f a water insoluble copper arsenate in the w o o d , w h i c h will not  be  w a s h e d o u t w h e n the treated w o o d is p l a c e d i n service. With the g r o w i n g pressure f r o m environmental groups o n  conventional  w o o d preservatives, ammonia-based preservatives s h o w considerable promise  for  further d e v e l o p m e n t to increase their versatility as w o o d preservatives. M o s t o f the f o r m u l a t i o n s d e v e l o p e d u s e c o p p e r as t h e a c t i v e c a t i o n b e c a u s e o f its e x c e l l e n t fungicidal action. Industry c o n c e r n w i t h the toxicity a n d leaching o f arsenic led to interest i n replacing s o m e o f the arsenic. Clarke a n d R a k (1974) f o u n d that addition o f zinc oxide to A C A e n h a n c e d arsenic fixation. In this formulation, percent o f the arsenic oxide w a s replaced b y zinc oxide. T h i s lead to of ammoniacal copper zinc arsenate (ACZA)  development  w h i c h w a s first i n t r o d u c e d to  Canadian Standards Association (CSA), but was never developed Subsequently a similar ACZA  further.  formulation w a s introduced in the U n i t e d States in  1 9 8 1 i n w h i c h the C u : Z n : A s ratio w a s 1:1:1 ( B e s t a n d C o l e m a n , 1 9 8 1 ) . I n the A W P A  fifty  a p p r o v e d the 1:1:1 f o r m u l a t i o n o f A C Z A  into the preservative  ( M o r g a m , 1989). M o r e recently, a m m o n i a c a l c o p p e r citrate ( C C ) a n d  1983 standard  ammoniacal  10  copper/quaternary a m m o r u u m compounds formulations ( A C Q ) have  been  developed w h i c h exhibit relatively l o w m a m m a l i a n toxicity and l o w  environmental  impact (Findlay and Richardson, 1983).  < T3  ©  as oo  ON  ci oo  ON  9  9  O X «•> cii  o X oo  9 o o  </->  I  IJg  13  Ov  o  X  o ON  o\  1^5  o  ON  o  9 u K x a §5  OV  O < o  c o a CO  0  1  o U  1 CA  o o< c4 cri  1 in  •  i  •ri oo' U") o  ui  o  + + oo ON  X © •  ON  ON  u  NO •>*•  O  vO  '**  O  °  Cl  ©  C)  O  ~-  12  2.3.1  Role of ammonia in improving preservative treatment T h e r e a s o n f o r the i n c r e a s e d p e n e t r a t i o n o f A C A t r e a t m e n t is n o t  well  k n o w n , b u t is b e l i e v e d to b e a s s o c i a t e d w i t h the a c t i o n o f a m m o n i a o n  the  c e l l u l o s e , w h i c h r e s u l t s i n a s e p a r a t i o n o f t h e h y d r o g e n b o n d i n g ( W i n a n d y et al., 1 9 8 9 ) . T h e r e f o r e , a m m o n i a is a n e x c e l l e n t s w e l l i n g agent. A m m o n i a is also c a p a b l e o f dissolving encrusting materials s u c h as fats, w a x e s , resins polygalacturonic acids (Hulme, 1979), thus enhancing preservative  and penetration,  especially in refractory species. C o n s i d e r a b l e effort has m a d e i n order to understand the effect o f a n h y d r o u s a m m o n i a o n various components o f the w o o d (Bariska a n d Popper, 1971 1975; R a k 1977). T h e s e studies indicated that a m m o n i a penetrated the  and amorphous  c e l l u l o s e first, t h e n the cellulose, h e m i c e l l u l o s e a n d lignin, a n d e v e n t u a l l y  the  c r y s t a l l i n e cellulose. W a t e r d o e s n o t enter the crystalline r e g i o n o f c e l l u l o s e a n d is s o r b e d o n l y b y t h e p a r a c r y s t a l l i n e r e g i o n o f c e l l u l o s e ( B a r i s k a et al., 1 9 6 9 ) . S c h u e r c h ( 1 9 6 4 ) p o i n t e d o u t that a m m o n i a is as u p e r i o r s o l v e n t f o r b o t h the  major  p o l y m e r systems -the phenolic lignin binder a n d the polysaccharide system in the c e l l w a l l . A l t h o u g h t h e l i g n i n is ab r a n c h e d a n d c r o s s l i n k e d p o l y m e r , w h e n p e n e t r a t e d b y a m m o n i a , it s w e l l s , b e c o m e s soft, b u t its m o l e c u l e s a r e n o t or completely separated. T h e hemicellulose m a y be deacetylated a n d  fully dissolved  acetamide  m a y b e f o r m e d d u r i n g t r e a t m e n t w i t h a m m o n i a . It w a s r e p o r t e d t h a t u r o n i c a c i d g r o u p s m a y b e c o n v e r t e d to a m m o n i u m salts or a m i d e s ( S c h u e r c h ,  1964)  Rak (1977) reported, i n his studies o f spruce, that the permeability spruce r o u n d w o o d in the radialdirection w a s i m p r o v e d using  of  ammoniacal  solutions o f i n o r g a n i c salts, c o m p a r e d w i t h a q u e o u s solutions. H e also n o t i c e d  that  the a m m o n i a c a l system penetrated spruce 1.7-1.8 times faster i n the radial direction than the acidic C C A ,while the permeability in the tangential  direction  13  w a s 3 . 8 t i m e s f a s t e r . T h ep e r m e a b i l i t y o f s p r u c e s a p w o o d t o a n a q u e o u s a m m o n i a c a l solution o f inorganic salts w a s f o u n d t o b e better t h a n a p l a i n w a t e r solution.  2.3.2  A m m o n i a c a l c o p p e r (II)  complexes  Addition o f a m m o n i u m hydroxide solution to a n aqueous solution o f the copper(II) ions results i n t h e setting u p o f a c o m p l e x equilibrium, involving t h e successive replacement o f coordinated water b y a m m o n i a according to the equation:  C u ( H 0 ) 2 + + nNH 2  6  3  o  Cu(NH ) (H 0) . 2+ + 3  n  2  6  n  n H  2  0  T h e successive f o r m a t i o n constants f o rt h e s e reactions a r e s h o w n i n T a b l e 2-1-2, together w i t h t h o s e f o rt h e N i ( H 0 ) 6 2  2  +  cation. F o rnickel(II) there is a  smooth  d e c r e a s e f r o m K I t o K 6 , w h e r e a s f o rcopper(II), K 6 i s z e r o a n dK 5 i s v e r y s m a l l , indicating a negligible tendency to take u p m o r e than four a m m o n i a  groups.  T a b l e 2 - 1 - 2 T h esuccessive f o r m a t i o n constant f o rt h e copper(II) a n d n i c k e l ( I I ) i o n s w i t h a m m o n i a a s a l i g a n d ( H a t h a w a y et al. 1 9 7 0 ) K i  K  2  K  1  3  K  1  4  K i  K 5  1 6  C 2+  12000  3000  800  120  0.3  -  i2+  500  150  50  15  5  1  U  N  T h e most c o m m o n copper-ammonia complex C u ( N H 3 ) 4 ( H 0 ) 2  2  h a s a  distorted octahedral configuration around themetal a t o m with the four nitrogen b o n d s ( C u - N = 2 . 0 3 - 2 . 0 6 A ) c l o s e s t t o t h e c o p p e r a t o m i n a p l a n e a n dt w o less strongly b o u n d w a t e r ligands ( C u - 0= 2.59-3.37 A ) , o n a n axis p e r p e n d i c u l a r t o  14  t h i s p l a n e ( E m e l e u s , 1 9 7 3 , M a z z i , 1 9 5 5 ) . C o p p e r (II) i o n s c a n a l s o  form  c o m p l e x e s w i t h a m i n e s s u c h as e m y l e n e d i a m i n e a n d pyridine.  2.3.3  Reaction of ammonia and ammoniacal copper with wood and its components.  2.3.3.1 Reaction of ammonia with wood components Treatment of w o o d with aqueous a m m o n i a causes substantial changes in w o o d p r o p e r t i e s , (e.g. of internal surface  m o r e h y g r o s c o p i c , s w e l l i n g to ah i g h d e g r e e a n d d o u b l i n g area).  M a h d a l i k et al. ( 1 9 7 1 ) s t u d i e d t h e c h a n g e s i n t h e c h e m i c a l p r o p e r t i e s o f t h e w o o d treated w i t h liquid a m m o n i a . T h e y f o u n d that the reaction o f a m m o n i a moist w o o d fixed m o r e nitrogen than w h e n oven dried w o o d was reacted.  with  T h e y  a l s o n o t e d t h a t t h e e x t r a c t i v e s o f o a k f i x e d an o t i c e a b l y g r e a t e r a m o u n t o f n i t r o g e n , t h a n the l i g n i n - p o l y s a c c h a r i d e c o m p o n e n t s . G a s e o u s a m m o n i a is r e t a i n e d i n large a m o u n t s b y c e l l u l o s e fiber. C o t t o n m a y o c c l u d e 1 1 5 t i m e s its v o l u m e o f g a s e o u s a m m o n i a . W h e n the a m m o n i a has evaporated, the cellulose a p p e a r e d to  be  unchanged chemically. A q u e o u s ammonia, even w h e n concentrated (23-28 % NH3), s e e m e d t o h a v e n o e f f e c t o n c e l l u l o s e ( H e u s e r , 1 9 4 6 ) . A q u e o u s a m m o n i a i s reported to r e d u c e cellulose microfibrils into m o r e e l e m e n t a r y fragments. A s a result of rupture o f physical a n d h y d r o g e n bonding b e t w e e n complexes  of  carbohydrate macromolecules. T h e cleavage of chemical bonds between middle lamella a n d the cell wall in the middle lamella w a s  the  observed.  Solar a n d M e l c e r (1978) h a v e reported experiments to e x a m i n e the physical and chemical changes in lignin w h e n w o o d was treated with aqueous  ammonia.  T h e y f o u n d that the total n u m b e r o f acidic groups in the lignin decreased b y third a n d the carboxyl group content was reduced b y one half during the  one  treatment.  15  T h e i n f r a r e d spectra s h o w e d a n increase i n the a b s o r p t i o n at 1 6 7 0 c m  -  w h i c h  1  was  interpreted as e v i d e n c e for the f o r m a t i o n o f a-keto groups i n the side c h a i n o f the l i g n i n p h e n y l p r o p a n e u n i t s , a s ar e s u l t o f h y d r o l y s i s o f b o n d i n g b e t w e e n l i g n i n a n d holocellulose. T h e b a n d at 1240 c m  -  1  decreased after treatment w i t h  a m m o n i a  solution, as ac o n s e q u e n c e o f h y d r o l y s i s o f C - 0 ester a n d ether b o n d s . i n f r a r e d s p e c t r a a l s o c o n t a i n e d al o w e r i n g o f t h e b a n d at 1 7 4 0 c m w i t h ad e c r e a s e i n the n u m b e r o f c a r b o x y l g r o u p s i n the l i g n i n  -  1  T h e  , consistent  samples.  K a p l u n o v a et al. ( 1 9 8 6 ) s t u d i e d t h e r e a c t i o n o f n i t r o l i g r i i n f r o m c o t t o n - s e e d husks with aqueous a m m o n i a . A t r o o m temperature the lignin reacted  with  a m m o n i a m a i n l y through the carbonyl a n d carboxyl groups, f o r m i n g imines  and  a m m o n i u m s a l t s . K o v a l ' c h u k et al. ( 1 9 7 2 ) r e a c t e d l i g n i n f r o m s u n f l o w e r h u s k s aqueous a m m o n i a solution. T h e infrared spectra s h o w e d that the carboxylic reacted w i t h a m m o n i u m i o n s to f o r m a m m o n i u m salts, w h i c h further  with groups  converted  into amides. T h e y also pointed out that P-diketone structure in lignin can react w i t h a m m o n i a a n d lead to the f o r m a t i o n o f  amines.  2.3.3.2 Reaction of ammoniacal copper complex with cellulose An aqueous solution of tetraamminecopper hydroxide, [Cu(NH3)4](OH)2, is ag o o d s o l v e n t f o r d i s s o l v i n g cellulose, a n d is w i d e l y u s e d f o r the d e t e r m i n a t i o n o f p u l p i n t h e p a p e r a n d p u l p i n d u s t r y . It is p r e p a r e d b y cupric oxide in excess a m m o n i u m hydroxide solution. T h e  viscosity dissolving  tetramminecopper  hydroxide can swell, peptize, a n d eventually disperse cellulose. T h e dispersion  of  c e l l u l o s e i n c u p r i a r n m o n i u m h y d r o x i d e is a c c o m p a n i e d b y ac h e m i c a l r e a c t i o n . T h e interaction o f the cupric ions in strong a m m o n i u m hydroxide solution  with  glycol-like h y d r o x y l groups to f o r m complexes, has b e e n reported extensively. B a s e d o n conductivity measurements. R e e v e s (1949) suggested that such  complex  16  formation was critically dependent o n the distances between the h y d r o x y l groups, w h i c h between hydroxyl groups on adjacent carbon atoms was dependent o n angles b e t w e e n the groups. C o m p l e x f o r m a t i o n o c c u r r e d m o s t readily at the cis  the true  p o s i t i o n ( 0 ° angles) a n d at 6 0 ° angle, b u t d i d n o t o c c u r at the angles o f 1 2 0 ° o r  180°. H i n o j o s a a n d his co-workers (1974) studied the interaction  of  tetraamminecopper ions with cellulose using electron spin resonance (ESR). f o u n d that the reaction between tetraarnminecopper ions a n d cellulose w a s  T h e y very  rapid a n d reversible. W h e n the concentration o f a m m o n i a w a s decreased in the cupric i o n - a m m o n i u m hydroxide-cellulose complexes, the E S R signal due  to  p a r a m a g n e t i c r e s o n a n c e o f the c o m p l e x d e c r e a s e d o r w a s lost. S i m i l a r results obtained w h e n potassium hydroxide was r e m o v e d f r o m the complexes  were  formed  w h e n copper sulphate dissolved in potassium hydroxide. It w a s c o n c l u d e d t h a t t h e r e a c t i o n o f t e f r a a n m i i n e c o p p e r i o n s w i t h h y d r o x y l groups o n the cellulose to f o r m c o m p l e x e s d e p e n d e d o n a n  adjacent  o p t i m u m  distance between o f the h y d r o x y l groups. Evidently, wetting o f cellulose w i t h solutions o f strong bases allowed the adjacent h y d r o x y l groups to  fibers favorable  positions to y i e l d this o p t i m u m arrangement. W h e n the base w a s r e m o v e d , occurred to give less favorable positions o f the h y d r o x y l groups for  rotation  complexing  w i t h c u p r i c i o n s ( H i n o j o s a et al., 1 9 7 4 ) ) .  2.3.4  Fixation of ammoniacal copper preservatives in wood A m m o n i a c a l copper preservatives have been examined b y H u l m e  (1979).  T h e fixation m e c h a n i s m of ammoniacal copper preservatives in w o o d has reported b y Eadie and Wallace (1962), Clarke and R a k (1974) and (1984). F o l l o w i n g the impregnation o f the a m m o n i a c a l copper  been  S u n d m a n  preservative  s o l u t i o n i n t o the w o o d , it h a s b e e n s u g g e s t e d that t e t r a a r m n i n e c o p e r i o n s r e a c t  b y  17  i o n e x c h a n g e w i t h functional groups i n the w o o d s u c h as c a r b o x y l i c ( K u p c h i n o v et ah,  groups  1975). In addition, the evaporation o f a m m o n i a causes  the  b r e a k d o w n o f the c o m p l e x e s i n solution to f o r m water-insoluble c o p p e r salts, s u c h as c o p p e r arsenate i n the case o f A C A (Hartford, 1973). T h e a b o v e mechanisms have not been verified  fixation  experimentally.  T h e generally accepted fixation theory for ammoniacal copper  preservatives  i n w o o d w a s c h a l l e n g e d i n the late 1970's, w h e n it w a s o b s e r v e d that  ACA-treated  spruce pole sections stored outdoors retained enhanced nitrogen levels, m o r e  than  t w o years after treatment ( R u d d i c k , 1979). A n analysis o f four z o n e s w a s m a d e ,  at  the surface (0 to 5m m ) , at the limit o f the c o p p e r penetration, the h e a r t w o o d just b e y o n d the limit o f the copper penetration, a n d the center o f the cross section. results s h o w e d that nitrogen level w a s greatly e n h a n c e d i n the ACA-treated  T h e  wood,  the nitrogen content a p p e a r i n g to b e related to the A C A retention. I n addition, there w a s evidence that the a m m o n i a h a d penetrated b e y o n d that achieved b y  the  copper. R e c e n t l y electron spin resonance ( E S R ) w a s u s e d to study the c o p p e r i n a m m o n i a c a l c o p p e r t r e a t e d w o o d ( R u d d i c k et al., 1 9 9 2 ; H u g h e s et al, 1 9 9 4 ) . f o u n d that the copper-nitrogen c o m p l e x e s w e r e f o r m e d i n the w o o d after with ammoniacal copper  2.3.5  ESR  T h e y  treatment  solution.  spectral analysis of wood treated with ammoniacal copper  preservatives. 2.3.5.1 The  principal of  ESR  T h e electron h a s as p i n q u a n t u m n u m b e r . I n the p r e s e n c e o f a n a p p l i e d m a g n e t i c field, different energy states arise f r o m the interaction o f a n u n p a i r e d electron spin m o m e n t with the magnetic field, resulting in the alignment o f the  18  electron spin m o m e n t relative to the applied field. Only electromagnetic with the frequency  radiation  (v) v = g p H / h  where  g for a free electron is 2.0023 P is the electron Bohn magneton H  is the applied field strength  h is Planck's constant  contains the right a m o u n t o f energy to p r o d u c e transitions b e t w e e n the g r o u n d a n d e x c i t e d e n e r g y states o f the e l e c t r o n . F o r that it g i v e s a n E S R signal. T h e p a i r e d electrons do not give an E S R signal since paired electrons have spins with  opposite  directions. U n p a i r e d electrons arise f r o m incompletely filled electron shells, e x a m p l e s are f o u n d i n the d-orbitals o f transition m e t a l i o n s e.g. C u  2  +  , Ni  m a n y 2  +  etc.  '  or the excited state m o l e c u l a r orbitals o f p a r a m a g n e t i c species s u c h as radicals. T h e interaction o f the magnetic m o m e n t o f those unpaired electrons with a radio frequency electromagnetic field in the m i c r o w a v e region a n d a simultaneously a p p l i e d static m a g n e t i c field leads to absorption o f e n e r g y b y the sample. t h e r e is af r e q u e n t i n t e r a c t i o n b e t w e e n t h i s u n p a i r e d e l e c t r o n a n d t h e  Further,  magnetic  m o m e n t o f n u c l e i i n t h e s a m p l e w h i c h g i v e s r i s e t o ah y p e r f i n e s t r u c t u r e i n t h e s p e c t r u m . A s ar e s u l t , an u c l e u s o f s p i n Ig i v e s r i s e t o a s p l i t t i n g o f E S R l i n e 2 1 + 1  into  components, all o f equal intensity separated b y the coupling constant A  (Fig. 2-1-1). Therefore, E S R results are usually reported i n terms o f a  spin  H a m i l t o n i a n a n d e x p r e s s e d a s t h e 'g' a n d ' A ' t e n s o r s , t h e p r i n c i p a l v a l u e s o f w h i c h in anisotropic spectra yield information about the molecular environment o f the unpaired electron responsible for the resonance a n d the nature o f the nucleus interacts  with.  it  19  2.3.5.2 E S R analysis of a m m o n i a c a l copper treated  w o o d  It is p o s s i b l e t o o b s e r v e t h e E S R s p e c t r u m o f C C A - o r A C A - t r e a t e d  wood,  s i n c e c o p p e r (II) is p a r a m a g n e t i c . T h i s a r i s e s b e c a u s e c o p p e r (II) c o n t a i n s  an  unpaired electron in the d -electronic configuration, in w h i c h the unpaired electron 9  o c c u p i e s t h e d 2-y2 o r b i t a l a n d a l l o t h e r d - o r b i t a l s a r e d o u b l y o c c u p i e d .  T h e  x  m a j o r i t y o f c o p p e r (II) c o m p l e x e s h a v e a d i s t o r t e d o c t a h e d r a l g e o m e t r y , w i t h two axial bonds being longer than those in the  the  plane.  T h e E S R spectral hyperfine structure results f r o m the interaction  of  u n p a i r e d e l e c t r o n w i t h t h e n u c l e u s . F o r c o p p e r (II) a n d its n u c l e a r s p i n v a l u e 1 = 3 / 2 , t h e E S R s p e c t r u m o f C u (II) c o m p o u n d s w i l l s h o w f o u r e q u a l l y  of  spaced  f e a t u r e s (21 + 1) d u e to the h y p e r f i n e interaction. A n e a r l y E S R s t u d y o f C C A t r e a t e d w o o d w a s c a r r i e d o u t b y P l a c k e t t et al ( 1 9 8 7 ) w h o u s e d r a d i a t a p i n e radiate)  {pines,  a n d extracted lignin i m p r e g n a t e d w i t h C C A a n d c o p p e r sulfate. T h e E S R  results indicated that hydrated Cu  2 +  ions w e r e residing i n fixed sites w i t h i n the  t i m b e r . M o r e d e t a i l e d w o r k b y R u d d i c k et al ( 1 9 9 2 ) a n d H u g h e s et al ( 1 9 9 2 ) f o c u s e d o n other c o p p e r species as w e l l as C C A . T h e c o p p e r sulphate  treated  w o o d e x h i b i t e d a h y p e r f i n e s t r u c t u r e a t l o w e r f i e l d , w h i c h s u g g e s t e d a d 2_ 2 x  v  g r o u n d state, i n w h i c h the c o p p e r w a s b o n d e d to f o u r (or six) o x y g e n a t o m s i n a square planar (or distorted octahedral) configuration. W o o d impregnated  with  copper acetate dissolved in either water or methanol gave similar spectra,  w h i c h  also c o m p a r e d w e l l to that o f c o p p e r sulphate treated w o o d . Clearly, i n these treatments any interaction with the substrate was independent o f the employed (Ruddick,  three  solvent  1992).  In ammoniacal-copper treated w o o d the copper ions h a d ahigher A / / value a n d l o w e r g// v a l u e t h a n t h o s e f o r t h e c o r r e s p o n d i n g a q u o c o p p e r i o n , r e s u l t i n g f r o m a n i n c r e a s e i n the e l e c t r o n d e n s i t y o n the c o p p e r , s i n c e n i t r o g e n is a m o r e  20  electron-rich atom than oxygen (Peisach and Blumberg, 1974). This supports hypothesis that in a m m o n i a c a l copper treated w o o d copper-nitrogen  the  bonded  c o m p l e x e s a r e f o r m e d i n t h e w o o d . H u g h e s et al ( 1 9 9 2 ) a l s o r e p o r t e d t h a t  the  c o p p e r - n i t r o g e n b o n d e d c o m p l e x e s i n w o o d h a d a h i g h l e a c h i n g r e s i s t a n c e . It h a s b e e n s h o w n that for a copper c o m p l e x possessing a square planar geometry is a n i n v e r s e d e p e n d e n c e o f A / / o n g// ( P e i s a c h a n d B l u m b e r g , 1 9 7 4 ) .  there  This  d e p e n d e n c e c a n help to identify the copper-ligand groups i n the c o p p e r  complexes  o f k n o w n structure. R u d d i c k ( 1 9 9 2 ) h a s c o m p i l e d g// a n d A / / f o r a series o f c o p p e r treated ponderosa pine samples a n d suggested that the E S R technique might e m p l o y e d to define the geometric relationship o f isostructural c o p p e r  be  complexes  f o r m e d in treated w o o d (Fig. 2-1-2). In the figure, complexes with four planar 2+  c o p p e r - o x y g e n b o n d i n g , e.g.  [Cu(H20)4]  , lie to the l o w e r right, w h i l e  the  corresponding molecules containing four copper-nitrogen bonds in a plane s m a l l e r v a l u e s o f g// a n d l a r g e r v a l u e s o f A / / a n d t h e s e c o m p l e x e s a r e l o c a t e d the u p p e r left o f the plot. T h e parameters for c o p p e r b o u n d to t w o nitrogen a n d t w o o x y g e n a t o m s lie b e t w e e n those o f the t w o  extremes.  have o n atoms  Fig. 2-1-1 E n e r g y levels for a system with electron spin S=l/2 a n d nuclear spin 1=3/2 s h o w i n g the effects o f magnetic field a n d the nuclear q u a d r u p o l e m o m e n t .  22  1 2  200  § 180  o i—i  °n On  f  o  o  9  Os  «  <  4  -  X  o  160 . 1 3 14 3  140 1  1  2.2  2.3  „  9) l . o  2.4  8//  F i g . 2-1-2 R e l a t i o n , b e t w e e n the m a g n e t i c p a r a m e t e r s g// a n d A / / f o r c o p p e r - t r e a t e d w o o d , A v i c e l a n d c o p p e r solutions. 1) W o o d treated with. C u S O ^ K k O i n w a t e r at r o o m t e m p e r a t u r e , 2) W o o d treated w i t h Cu(CH3COO)2 i n w a t e r at r o o m t e m p e r a t u r e , 3 ) W o o d treated w i t h Cu(CH3COO)2 i n m e t h a n o l at r o o m t e m p e r a t u r e , 4 ) W o o d t r e a t e d w i t h Q1CO3 i n N H 4 O H a t r o o m t e m p e r a t u r e , 5 ) A v i c e l t r e a t e d w i t h CUCO3 i n N H 4 O H a t r o o m t e m p e r a t u r e , 6 ) Q1CO3 i n N H 4 O H at 7 7 K , 7) W o o d treated w i t h [ C u ( e n ) 2 ] i n w a t e r at r o o m temperature, 8) W o o d treated with. [ C u ( e n ) 2 ] S 0 4 i n water at r o o m temperature, 9) W o o d treated w i t h C T S ™ i n w a t e r at. r o o m t e m p e r a t u r e , 10) A v i c e l t r e a t e d w i t h C T S ™ i n w a t e r at. r o o m temperature, 11) C u H D O in toluene at 7 7 K , 12) C T M ™ at 7 7 K , 13) W o o d treated w i t h C i i E L D O / a m i n e at 7 7 K , 14) C i u H D O / a m i n eat 7 7 K , 15) A v i c e l treated w i t h C u H D O / a m i n ei n water at r o o m temperature. * 2 +  *CuHDO - Bis-(N-cyclohcxyldia2criiurndioxy)-copper (II); cn - l,2-diarninc>ethane.  1  23  2.4  Enhanced nitrogen content in ammoniacal copper treated wood  2.4.1  Nitrogen requirement for fungal  growth  Like all living organisms, fungi have certain requirements for growth  and  survival. T h e major growth needs o f wood-inhabiting fungi are water: free  water  o n t h e s u r f a c e s o f c e l l l u m e n ; o x y g e n : a t m o s p h e r i c o x y g e n at ar e l a t i v e l y l o w f o r m o s t f u n g i ; af a v o r a b l e t e m p e r a t u r e r a n g e f r o m 1 5 t o 4 5 ° C f o r m o s t  w o o d -  i n h a b i t i n g f u n g i ; a d i g e s t i b l e s u b s t r a t e ( w o o d , etc.) p r o v i d e s e n e r g y  and  m e t a b o l i t e s f o r s y n t h e s i s v i a m e t a b o l i s m ; af a v o r a b l e p H r a n g e  3to 6 for  from  m o s t w o o d - i n h a b i t i n g fungi; nitrogen a n d micronutrients s u c h as vitamins essential e l e m e n t s s u c h as p h o s p h o r u s ( Z a b e l a n d M o r r e l l ,  level  and  1992).  Fungi require asubstantial a m o u n t o f nitrogen for the synthesis o f protein a n d other cell constituents or products s u c h as nucleoproteins,  lipoproteins,  e n z y m e s , a n d the c h i t i n i n h y p h a l - c e l l w a l l s . H o w e v e r , n i t r o g e n is p r e s e n t  in  relatively s m a l l a m o u n t s i n w o o d , c o m p r i s i n g b e t w e e n 0.03 % a n d 0.1 % o f the d r y w e i g h t o f w o o d ( A l l i s o n , et al., 1 9 6 3 ) . D i s t r i b u t i o n o f n i t r o g e n i n  w o o d  i n d i c a t e s ar e d u c t i o n i n n i t r o g e n c o n t e n t f r o m o u t e r t o i n n e r s a p w o o d , w i t h lowest amounts being found in heartwood. T h e pith section often  the  contains  relatively large a m o u n t s o f n i t r o g e n . Little is k n o w n c o n c e r n i n g the n a t u r e o f the nitrogenous materials in w o o d , principally because the small amounts present  are  commercially unimportant. B u t for wood-inhabiting microorganisms and insects that derive their nourishment primarily  from  w o o d itself, these s m a l l a m o u n t s  nitrogen are o f p a r a m o u n t importance. T h e capacity o f d e c a y fungi to nitrogen needs wholly  from  the l o w a m o u n t s a v a i l a b l e i n w o o d is e v e n  meet m o r e  surprising, because o f the prodigious n u m b e r o f spores released (nitrogen of about  3%).  of  content  24  A series o f studies o n the availabihty a n d roles o f nitrogen in deterioration (Cowling and Merril, 1966; Merril and Cowling, 1966;  w o o d C o w l i n g  1970) s h o w e d that decay fungi probably conserve nitrogen b y h y p h a l  autolysis  d u r i n g w h i c h n i t r o g e n is r e c y c l e d t o w a r d the h y p h a l tips. T h e c l o s e r e g u l a t i o n  of  the cellulose e n z y m e s y s t e m i n s o m e w o o d - d e c a y f u n g i m a y also serve to  conserve  nitrogen. Bacteria are often associated with fungi in the decay process a n d  m a y  play a n important interactive role in nitrogen cycling a n d fixation in nitrogen c y c l i n g a n d f i x a t i o n d u r i n g s o m e n a t u r a l w o o d - d e c a y p r o c e s s e s ( A h o et al., L a r s e n et ah, 1 9 7 8 ) . S e v e r a l r e s e a r c h e r s h a v e s h o w n t h a t i n c r e a s i n g t h e  1974;  nitrogen  content of wood, frequently b y addition of an a m m o n i u m chemical, increased  the  rate o f decay b y wood-destroying fungi (Findlay, 1934; A m b u r g e y a n d Johnson, 1978). Fungal nitrogen sources are quite varied a n d m a y be organic or inorganic in nature. In general, fungi do not metabolize all nitrogen sources with equal case. A f u n g u s m a y h a v e ar e q u i r e m e n t f o r n i t r o g e n i n a s p e c i f i c f o r m . F u n g i m a y  utilize  inorganic nitrogen i n the f o r m o f nitrates, nitrites or a m m o n i a , or organic  nitrogen  i n the f o r m o f a m i n o acids. A m m o n i a is o f t e n the b e s t n i t r o g e n s o u r c e . laboratory studies a m m o n i a m a y affect m e d i a p H a n d hence, growth  During  responses  (Zable a n d Morrell, 1992). Af e w fungi m a y b e able to obtain nitrogen v i a the direct utilization of atmospheric nitrogen (Smith,  2.4.2  1970).  Nitrogen content in ammoniacal copper treated wood R u d d i c k (1979) f o u n d that the nitrogen content i n ACA-treated  w o o d w a s m u c h higher than that i n untreated w o o d . In addition, the  spruce a m m o n i a  penetration w a s greater than that o f the preservative solution, resulting i n nitrogen enrichment in w o o d where no copper could be detected. These observations  are  25  very important a n d indicate that the addition o f nitrogenous materials to w o o d  m a y  i n c r e a s e its s u s c e p t i b i l i t y to d e c a y . T h e h i g h n i t r o g e n l e v e l s at s u r f a c e o f t h e treated w o o d are unlikely to be important, since the preservative retention will also b e h i g h a n d w i l l deter f u n g a l attack. H o w e v e r , at locations further f r o m surface, where an enhanced nitrogen level have b e e n observed, the  the  preservative  r e t e n t i o n is m u c h l o w e r t h a n that r e q u i r e d to p r e v e n t d e c a y . T h u s a n y extending to the inner area b e y o n d the treated zone, either b y d e e p  damage  checking  during weathering or b y mechanical damage, could expose w o o d with a high nitrogen content a n d a l o w preservative retention. S u c h a situation c o u l d lead to decay o f the exposed  wood.  A l k a l i treatment o f w o o d (e.g., s o d i u m h y d r o x i d e a n d  a m m o n i u m  hydroxide) increased the decay resistance in both the laboratory a n d the field studies, w h i c h has lead to suggestion o f a n alkali treatment as a n  alternative  m e t h o d o f w o o d p r o t e c t i o n . It h a s b e e n a s s u m e d t h a t t h e a l k a l i t r e a t m e n t  m a y  d e s t r o y t h i a m i n e ( D w i v e d i a n d A r n o l d , 1973), w h i c h is essential f o r f u n g a l growth. B u t H i g h l e y (1973) f o u n d that l o w decay o f ammonia-treated w o o d  was  not related to destruction o f thiamine i n w o o d . H e f o u n d that the p H  and  a m m o n i a c a l nitrogen content o f w o o d affected decay resistance, a n d  suggested  that after treatment w i t h a m m o n i a , toxic a m m o n i a c o m p o u n d s w e r e f o r m e d . A m b u r g e y a n d J o h n s o n (1978) reported that the increased decay resistance  of  a m m o n i u m hydroxide-treated w o o d m a y be d u e to factors that inhibit germination of  basidiospores. Recently, R u d d i c k (1992a) reported that soil-leached CCA-treated  mini-  stakes w e r e attacked b y d e c a y fungi, c a u s i n g considerable w e i g h t losses at g a u g e r e t e n t i o n s a b o v e t h o s e c o n s i d e r e d t o b e e f f e c t i v e . It w a s s u g g e s t e d t h a t t h i s  26  p h e n o m e n o n w a s linked to bacterial action o n the chemicals i n the w o o d . action caused a b r e a k d o w n o f the copper complexes, a n d m a d e t h e m  This  soluble.  27  2.5  Black discoloration of Douglas-fir wood treated with ammoniacal copper preservatives  2.5.1  Importance of Douglas-fir wood species in B.C. D o u g l a s - f i r (Pseudotsuga  menziesii  ( M i r b . ) Franco),  native in C a n a d a and  the N o r t h w e s t o f the U . S , is o n e o f the p r e d o m i n a n t c o m m e r c i a l t i m b e r s p e c i e s i n British C o l u m b i a , accounting for 14 per cent o f total cubic v o l u m e o f  softwood  p r o d u c t i o n i n 1 9 7 5 . It is t h e s t r o n g e s t c o m m e r c i a l s o f t w o o d i n C a n a d a b e i n g  used  extensively for structural purposes, s u c h as poles, pilling a n d bridge timber.  Much  o f the softwood p l y w o o d p r o d u c e d o n the Pacific C o a s t contains  Douglas-fir  veneers. T h e effective preservative treatment o f this h e a r t w o o d will therefore very important, particularly for s a w n w o o d  2.5.2  products.  Treatability of Douglas-fir D u r i n g the last t w o decades, v a c u u m - i m p r e g n a t e d s a w n w o o d has  b e c o m e (Tsuga-  acceptable in c o n s u m e r use. In western C a n a d a , the h e a r t w o o d o f h e m l o c k heterophylla  (Raf.) Sarg)  a m a b i l i s f i r (Abies spp) i s g e n e r a l l y r e g a r d e d a s  relatively e a s y to treat, w h i l e that o f D o u g l a s - f i r is c o n s i d e r e d to b e m o r e to treat.  be  B r a m h a l l (1966) reported that the permeability o f Douglas-fir  being difficult  heartwood  p r o d u c e d in British C o l u m b i a w a s extremely variable, with that g r o w n east o f the c o a s t a l r a n g e b e i n g r e f r a c t o r y , i.e., u n t r e a t a b l e , w h e r e a s t h a t f r o m V a n c o u v e r Island (coastal) w a s m u c h easier to pressure impregnate w i t h preservative.  This  observation was supported b y W e a v e r a n d Levi (1979). T h e reasons for the refractory nature o f Douglas-fir are not fully understood. Liese a n d B a u c h (1967) h a v e p r o p o s e d that the l o w p e r m e a b i l i t y o f the r a y cells is d u e to the  relatively  small proportion of ray tracheids. However, H a c k b a r t h and Liese (1975) reported that neither the n u m b e r n o r the area o f ray cells influenced the  preservative  28  penetration, a n drather increasing density a n dthe proportion o f latewood reduced preservative  both  absorption.  In general, the p r o b l e m o f treating refractory species h a s b e e n attacked b y three basic methods. There are: (1) T h e use o f enzymes, moulds, o r bacteria (biological) to enhance the permeability b y biological attack o f the pit structure; (2) incising, w h i c h m a k e s u s e o f t h e superior l o n g i t u d i n a l penetration to p r o d u c e  a  sheet o f treated w o o d to the depth o f the incision, a n d variation o f the treating conditions (physical); a n d (3) preservative type a n d formulation  (chemical).  T h e appropriate selection o f preservative or additives forformulation c a n increase the penetration o f w o o d . H e n c e , t h e p r o b l e m o f treating difficult-to treat species such as Douglas-fir has been attacked b y using preservatives  with  e n h a n c e d penetration characteristics (e.g. A C A ) a n d modifications o f these formulations. R u d d i c k (1989) investigated the treatability o f Douglas-fir with ACA  a n d C C A f o r compatible solution strength, a n d f o u n d that the penetration  and retention o f A C A were higher than those o f C C A . It i s w e l l k n o w n b y w o o d treaters t h a t t h e A C A t r e a t m e n t o f c e r t a i n  w o o d  species, s u c h as D o u g l a s - f i r , results i n a d a r k e n i n g o f t h e w o o d d u r i n g treatment. It has b e e n postulated that the darkening is related to the presence o f a m m o n i a i n ACA  solution since treatment with C C A ,w h i c h also contains copper a n d arsenic,  does n o t give this reaction (Ruddick,  2.5.3  1979).  Extractive chemistry o f Douglas-fir There are four chemical components present i n w o o d : cellulose,  lignin,  hemicellulose a n d extractives. Cellulose, the m a i n c o m p o n e n t i n w o o d , is a linear m a c r o m o l e c u l e c o m p o s e d o f (l-4)-P-D-glucopyranose. Ligriin is a c o m p l e x a n d h i g h molecular weight p o l y m e r built u p o n phenylpropane units, w h i c h are linked  29  b y b i p h e n y l , a r y l - a l k y l o r ether linkages. L i g n i n i n s o f t w o o d is c o m p o s e d  of  g u a i a c y l units, w h i l e that i n h a r d w o o d is b u i l t u p w i t h g u a i a c y l - s y r i n g y l units. Hemicelluloses are c o m p l e x mixtures of polysaccharides, a n d c o m p o s e d o f various sugar units, with shorter molecular chains a n d s o m e branching. Only  m i n o r  structural variations are f o u n d in the lignin a n d hemicelluloses o f different plants. A large variety of w o o d components, although usually representing a m i n o r fraction, are soluble in neutral organic solvents or water. T h e y are  called  extractives, largely comprised o f polyphenolic organic molecules. T h e compositions vary widely in different w o o d  extractive  species.  T h e structural constituents of Douglas-fir wood, n a m e l y  cellulose,  hemicellulose a n d lignin, o c c u r i n r o u g h l y the s a m e p r o p o r t i o n as i n other c o n i f e r o u s w o o d s . T h e c h e m i c a l c o m p o s i t i o n o f D o u g l a s - f i r w o o d is s h o w n Table 2-1-3 (Isenberg, 1980). F o r comparison, the table also includes data s e v e r a l s o f t w o o d s . F o s t e r et a / . ( 1 9 8 0 ) c h a r a c t e r i z e d t h e s a p w o o d a n d  in on  heartwood  extracts o f Douglas-fir, a n d f o u n d that the diethyl ether extractive (mg/g  oven-  dried extract-free w o o d basis) recovered f r o m the h e a r t w o o d w a s three times f r o m the  that  sapwood.  N o single, universal solvent will r e m o v e all o f the various c o m p o u n d s . In order to ensure that the extractives h a v e b e e n  extractive  quantitatively  r e m o v e d , a n u m b e r o f different solvents m u s t b e e m p l o y e d . Generally, to  separate  extractives, alcohol or acetone, ether a n d water are needed. A c e t o n e leaches the c o l o r i n g matter, tannins, w h i l e ether r e m o v e s oils, fats a n d resins. Cold leaches the soluble short-chained carbohydrates as w e l l as s o m e free acids salts. A c c o r d i n g l y , these three solvents w e r e u s e d i n this s t u d y to p r e p a r e containing the m a j o r  extractives.  out water and  fractions  30  Early w o r k o n the.isolation o fDouglas-fir extractives w a s concerned the oleoresins (Benson a n d McCarthy,  with  1 9 2 5 ) . T h eo l e o r e s i n c o l l e c t e d f r o m b o r i n g  the tree w a s distilled w i t h superheated steam at a temperature o f 150°C  f o rt h e  p u r p o s e o f s e p a r a t i n g t h e v o l a t i l e o i la n d r o s i n . T h e v o l a t i l e o i lc o n t a i n e d with small amounts o flimonene and terpineol (Schorger, 1917). A analysis o ft h eentire extractive fraction w a sm a d e b y Graham  ct-pinene  systematic  and Kurth  (1949).  T h e y investigated t h e ether, acetone, a n dcold-water extracts f r o m three  specimens  o f Douglas-fir heartwood. I n t h e ether extract, oleic, linoeic, lignoceric a n d abietic acids, phytosterol a n d tannin were found. T h e fatty acids were present both i nt h e f r e e a n dc o m b i n e d s t a t e s , w h e r e a s t h e r e s i n a c i d s w e r e i s o l a t e d o n l y a s t h e f r e e a c i d s . A p e n t a h y d r o x y f l a v a n o n e a n dc a t e c h o l t a n n i n w e r e i s o l a t e d f r o m t h e acetone extract. A p p r o x i m a t e l y 7 0 percent o ft h e c o l d water extract w a s a galactan. D i h y d r o q u e r c e t i n , a m a j o r D o u g l a s - f i r h e a r t w o o d p o l y p h e n o l , w a s first d e s c r i b e d b y P e w ( 1 9 4 8 ) . A s m a yb e e x p e c t e d , t h e h e a r t w o o d o f D o u g l a s - f i r contained higher amounts o fextractives (3.6%) than t h ecorresponding (1.3%) ( H a r v e y a n dT s u n e o , 1974). A b o u t a decade later B a r t o n a n d  sapwood Gardner  ( 1 9 5 8 , 1 9 6 3 )a n d H a n c o c k ( 1 9 5 7 ) d e s c r i b e d d e t a i l e d a n a l y t i c a l m e t h o d s f o rt h e d e t e r m i n a t i o n o f d i h y d r o q u e r c e t i n i n D o u g l a s - f i r . T h ed i h y d r o q u e r c e t i n c o n t e n t i n heartwood varied within a n d b e t w e e n trees o ft h e same species, ranging f r o m to 1.5 percent i nDouglas-fir. Within  zero  a tree a general pattern o f increasing  concentration with increasing distance f r o m t h epith w a s evident i nt h e heartwood. A leucoanthocyamidin w a s also f o u n d i nDouglas-fir w o o d . (1972) isolated  Rogers and Manville  (-)-d5-4-[r(R)-5 -dimethyl-3-oxohexyl]-cyclohexane-l-carboxylic ,  acid f r o m t h epetroleum ether extract f r o m Douglas-fir  wood.  31  15 •§  cs pi  OS  a #  *  < > 2  t" r-'  cs r»° cs  vo  •S.-3 2? 5! 13  o  cs  5  ft.  .a  o  Si,  .S D-  •a 4 £  T3> •a 3  1 E  32  2.5.4  Effect of the extractives on w o o d  properties  T h e effect o f the w o o d extractives o n the properties o f timber have  been  studied b y several researchers. F o r example, s o m e conifer w o o d species  often  d a r k e n d u r i n g s t o r a g e ( M i l l e r et al.,  T h e  1983, Evanta and Halvorson, 1962).  b e h a v i o u r o f c e r t a i n c l a s s e s o f e x t r a c t i v e s is s u f f i c i e n t l y w e l l k n o w n to p r e d i c t the type o f color changes. T h e polyphenols have received m o r e attention than types o f extractives. T h e tendency o f polyphenols to discolor u n d e r  other  different  c o n d i t i o n s is p a r t l y d e p e n d e n t o n the n u m b e r o f v i c i n a l h y d r o x y l g r o u p s (Hillis, 1 9 6 2 ) . W h e n w o o d is e x p o s e d to air o r sunlight, p o l y p h e n o l s d a r k e n , d u e  to  oxidation w h i c h p r o d u c e d d a r k - b r o w n products. F o r example, the formation o f the b r o w n c o l o r stain i n w e s t e r n h e m l o c k is t h o u g h t to result f r o m o x i d a t i v e  reactions  o f extractives. T h e extractive that is b e l i e v e d to b e the m a i n c a u s e o f the  color  stain is c a t e c h i n , w h i c h u n d e r g o e s a t w o - s t a g e e n z y m e - c a t a l y z e d f o l l o w e d b y c o n d e n s a t i o n ( K r e b e r , 1 9 9 4 ; A v r a m i d i s et al.,  oxidation,  1993)  Another property of polyphenols containing ortho-dihydroxy and vicinal t r i h y d r o x y g r o u p i n g s , is their ability to b i n d m e t a l i o n s to f o r m c h e l a t e s , w h i c h i n m a n y cases are dark colored. T h e degree of discoloration w h e n metal w o o d depends o n several factors. These  contarninates  include:  (1) T y p e a n d quantity o f p o l y p h e n o l s present. I n m a n y cases,  the  polyphenols containing trihydroxy groupings give a darker color with metals  than  those containing ortho-dihydroxy groupings (Tardif, 1959). (2) T h e p H o f the solutions. T a r d i f ( 1 9 5 9 ) f o u n d that the c o l o r reactions dilute solutions o f c o m m e r c i a l tannic a c i d w i t h several m e t a l s at l o w  of  concentration  are dependent o n the p H o f the solution. Ferric ion f o r m e d blue, m a u v e , red, a n d dark-red collocations b e t w e e n the p H ranges o f 2.0-5.0, 5.0-7.0, 7.0-11.0, greater than p H 11,  respectively.  and  33  (3) T h e type, c h e m i c a l state a n d quantity o f metal. T h e m o s t  important  metals were iron, a l u m i n u m , a n d copper. W i t h dilute solutions o f ions a n d the c o l o r is m o s t intense at a p H o f 4.5. W i t h s t r o n g e r i o n c o n c e n t r a t i o n , intense b l u e c o l o r is f o r m e d o v e r a w i d e p H r a n g e . C o p p e r f o r m e d tannate complexes,  while a l u m i n u m ions formed a bright-yellow  T r o u g h t o n a n d C h o w (1973) studied the heat-induced  tannin, the  dark-brown color.  color-intensity  c h a n g e i n D o u g l a s - f i r a n d f o u n d t h a t its e x t r a c t i v e s c o n t r i b u t e d s i g n i f i c a n t l y to c h a n g e . D i h y d r o q u e r c e t i n , w h e n h e a t e d p r o d u c e d a p o w e r f u l c h r o m o p h o r e . It also reported that d m y d r o q u e r c e t i n p o s s e s s e d s o m e f u n g i c i d a l effect, inhibiting g r o w t h o f the m o s t sensitive f u n g i at concentrations cent (Kennedy,  1956).  this was  completely  o f less t h a n 0.5  per  34  3.  EXPERIMENTAL  3.1  Study of extractives in Douglas-fir heartwood responsible for black color in ammoniacal copper treated wood  3.1.1 Preliminary analysis of extractives In this study three k i n d s o f solvents w e r e u s e d to find out w h e t h e r  the  extractives w e r e responsible for the discoloration, a n d i f so, w h i c h fraction o f Douglas-fir extractives was responsible for the reaction w h i c h p r o d u c e d the  dark  colour. Douglas-fir h e a r t w o o d m e a l w a s extracted w i t h different solvents to the extractive fractions (Fig. 3-1-1). In these experiments, the solvents,  obtain  acetone,  diethyl ether a n d water were used. Each fraction o f extractives was reacted a m m o n i a c a l c o p p e r solution to determine w h e t h e r colored c o m p l e x e s  with  were  f o r m e d . W h e n t h e r e a c t i o n w a s p o s i t i v e , /. e. d a r k c o l o u r e d m a t e r i a l s w e r e  formed,  this fraction w a s retained a n d processed to further separate the c o m p o n e n t s  to  determine w h i c h c o m p o u n d in the fraction was responsible for the reaction. Two  20 g r a m samples of Douglas-fir heartwood m e a l were  extracted  separately w i t h either 100 m l o f acetone or diethyl ether for 2 4 h o u r s at 2 0 ° C . t w o solutions w e r e filtered a n d c o n c e n t r a t e d u n d e r v a c u u m at 2 0 ° C . T h e w e r e dried u n d e r v a c u u m b e l o w 3 0 - 4 0 ° C to constant weight. T h e  T h e  residues  acetone-  extracted w o o d m e a l w a s extracted a g a i n w i t h 100 m l o f distilled w a t e r at  40°C  f o r 2 4 h o u r s . T h e extract w a s filtered a n d c o n c e n t r a t e d at 6 0 ° C u n d e r r e d u c e d p r e s s u r e to p r o d u c e athird  residue.  T h r e e r e s i d u e s o b t a i n e d w e r e t h e n s u b j e c t e d t o ar e a c t i o n w i t h copper  solutions.  ammoniacal  35  T h e test solutions w e r e p r e p a r e d as  follows:  (i)  2 % of acetone-extractive residue in methanol  (ii)  2 % o f ether-extractive residue in methanol.  (iii) 2 % o f w a t e r - e x t r a c t i v e r e s i d u e i n w a t e r . O n e m l of each solution was reacted with 1 m l of 1.5% (w/w) solution copper sulphate in a m m o n i u m hydroxide. U p o n addition o f the  of  ammoniacal  copper solution, only the acetone-extracted residue i n m e t h a n o l f o r m e d a  dark  colored precipitate. T h e ether-extract p r o d u c e d a light green color solution,  and  water-extracted residue f o r m e d a light b r o w n solution with a trace o f precipitate. This dark color m a y be caused b y the presence o f acetone-extractive residues the water-extracted  in  fraction.  B a s e d u p o n t h e s e o b s e r v a t i o n s , it w a s c o n c l u d e d that a c o m p o u n d  was  present i n the acetone-extract w h i c h reacted w i t h a m m o n i a c a l c o p p e r solution to produce a black precipitate. T h e subsequent experiments therefore focused o n chemicals present in the acetone  extractives.  the  Douglas-fir meal Acetone  Ether Water  Acetone extractives  Cu-NH3 Soln.  Dark brown precipitate  F i g . 3-1-1 extraneous  Water extractives  Cu-NH3 Soln.  Light brown suspension  Ether extractives  Cu-NH3 Soln.  Light green precipitate  Preliminary extraction procedure for isolation compounds  of  37  3.1.2  Isolation and identification of the extractive reacting with ammoniacal copper solutions to produce a black color B e c a u s e o f the positive response reaction o f the acetone extractive  mixture  w i t h a m m o n i a c a l c o p p e r solution, further experiments w e r e designed to isolate a n d identify the c o m p o n e n t i n this mixture w h i c h w a s believed to be responsible t h e b l a c k c o l o r o n w o o d after it w a s t r e a t e d w i t h a m m o n i a c a l c o p p e r  for  solution.  C o l u m n chromatography was used for preliminary purification o f the components f r o m crude acetone-extracts.  T h e c o m p o u n d isolated f r o m  Douglas-  firwas examined b y ultraviolet ( U V ) , fourier transform infrared  spectroscopy  (FTIR), proton nuclear magnetic resonance (H-NMR)  spectrometry  and mass  (MS).  3.1.2.1 I  s  o  l  a  t  i  o  no  ft  h  ee  x  t  r  a  c  t  i  v  e  Douglas-fir heartwood sawdust was prepared b y grinding u p thin chips  cut  f r o m h e a r t w o o d p i e c e s , u s i n g aW i l e y m i l l , u n t i l t h e s a w d u s t w o u l d p a s s t h r o u g h a 20 m e s h  screen.  Extraction with  acetone  A large glass flask w a s u s e d to extract 800 g r a m s o f w o o d m e a l dried basis) with 1200 m l o f acetone. Afresh supply o f solvent was  (oven-  introduced  into the flask every t w o days after filtering the extracted solutions. T h e  extracts  w e r e c o m b i n e d a n d c o n c e n t r a t e d u n d e r r e d u c e d p r e s s u r e t o av o l u m e o f 3 0 0 m l . A 10 m l aliquot f r o m the concentrated extract w a s dried to constant w e i g h t u n d e r v a c u u m at 4 0 ° C . T h e total calculated y i e l d o f acetone-extract w a s 2.42 p e r c e n t the oven-dried weight o f the w o o d . Silica gel  titin  layer chromatography ( T L C )  w a s u s e d to e x a m i n e the extracts u s i n g p e t r o l e u m ether : a c e t o n e 3:1 m i x t u r e  as  of  38  the developing agent. E x p o s i n g the plate u n d e r ultraviolet light revealed that a c e t o n e extract c o n t a i n e d a m i x t u r e o f at least six  the  compounds.  U p o n addition o f 150 m l o f distilled water to the concentrated  extract  solution, a niilky-white suspension was obtained. T h e residual acetone in the solution w a s r e m o v e d under reduced pressure, while m a m t a i n i n g the  temperature  b e l o w 4 5 ° C . I n o r d e r to separate the c o m p o u n d p r e s e n t i n the m i x t u r e , it  was  extracted with two solvents possessing quite different solubilizing capabilities. colloidal s u s p e n s i o n w a s first extracted f o u r t i m e s w i t h 50 m l aliquots  T h e  of  chloroform. T h e chloroform extract was recovered. T h e remaining water layer  was  further extracted with four, 50 m l portions o f diethyl ether solvent. U s i n g these two different solvents enabled the separation of the components in the  crude  extracts into chloroform a n d ether soluble fractions. B o t h the ether a n d chloroform solutions w e r e dried over anhydrous s o d i u m sulfate for 30 minutes a n d filtered, a n d concentrated u n d e r r e d u c e d pressure. T h e oil-like materials  then were  obtained f r o m the chloroform fraction. After r e m o v i n g diethyl ether f r o m the second fraction, petroleum ether  was  a d d e d to the r e s i d u e to s e r v e as a p r e c i p i t a t i n g agent. T h e m i x t u r e w a s set a s i d e to crystallize. After standing in the refrigerator for twenty-four hours, a light b r o w n solid w a s filtered off, w a s h e d w i t h p e t r o l e u m ether a n d d r i e d i n the o v e n at  103°C  for four hours. I n o r d e r to e x a m i n e w h i c h p a r t o f the f r a c t i o n is r e s p o n s i b l e f o r the darkened color in the treated heartwood, a solution was prepared f r o m r e s i d u e b y d i s s o l v i n g it i n m e t h a n o l . A m m o n i a c a l c o p p e r s o l u t i o n s w e r e  each then  a d d e d to the solution o f e a c h extract. Only the substance f r o m the ether fraction could react with c o p p e r - a m m o n i a solution a n d f o r m a dark colored precipitate. Further separation o f the crude solid f r o m the ether fraction w a s accomplished using c o l u m n chromatography.  b y  39  C o l u m n  chromatography  Elution c o l u m n chromatography with silica gel w a s used  in this phase  of  the experiment. A plug o f cotton w o o l was placed in the bottom o f the c o l u m n m m i n diameter a n d a layer o f s a n d w a s a d d e d o n top o f the p l u g to p r o v i d e  50  an  e v e n b a s e f o r the silica g e l c o l u m n . A m i x t u r e o f p e t r o l e u m ether a n d a c e t o n e (3 : 2) w a s c h o s e n as the eluting solvent b a s e d u p o n t r i a le x p e r i m e n t s to d e t e r m i n e m a x i m u m separation o f the  the  components.  T h e c o l u m n was p a c k e d b y adding silica gel slurry in the solvent mixture. After the c o l u m n h a d b e e n prepared, the solvent level w a s l o w e r e d to the top the silica gel c o l u m n b y draining solvent f r o m the b o t t o m o f the column.  of  T h e  m i x e d residue to be separated w a s dissolved i n acetone, a n d applied carefully to the top o f the silica gel c o l u m n . T h e c o l u m n w a s then eluted w i t h a 3:2 mixture p e t r o l e u m ether a n d acetone. I n o r d e r to accelerate the elution speed, l o w p r e s s u r e w a s a p p l i e d at the top o f the c o l u m n . T h e elution w a s  of  nitrogen  monitored  periodically b y thin-layer chromatography ( T L C ) o n silica gel using  petroleum  ether: a c e t o n e (3:2) as the d e v e l o p i n g solvent. T h e T L C results w e r e  observed  u n d e r U V light. T h e desired fractions containing o n l y the p r i m a r y p r o d u c t o n the T L C evaluation w e r e collected a n d consolidated. E v a p o r a t i o n o f the  based eluent  p r o d u c e d a c r e a m white solid, w h i c h was filtered a n d dried.  Product purification T h e white c o m p o u n d was dissolved in a 5 0 % ethanol-water solution (solid : solvent = 1:50). A c t i v a t e d c a r b o n w a s a d d e d to the solution, a n d the  mixture  refluxed for 30 minutes before immediately being filtered. T h e filtered cake w a s h e d three t i m e s w i t h 5 0 % w a r m ethanol solution. T h e filtrate w a s  was  concentrated  u n d e r v a c u u m to small v o l u m e a n d p l a c e d i n the refrigerator overnight for  40  crystallization. A cream-white needle-crystal solid was obtained w h i c h  was  r e c o v e r e d b y f i l t r a t i o n . It w a s d r i e d at 1 0 5 ° C i n t h e o v e n f o r 6 h o u r s .  3 . 1 . 2 . 2 I d e n t i f i c a t i o no f i s o l a t e d Melting  c o m p o u n d  point  The melting point was measured o n a 6545-J17 microscope equipped with T h o m a s m o d e l 40 hot stage melting M a s s spectrometry  apparatus.  ( M S )  The m a s s spectrum o f the white crystalline solid w a s obtained b y  M a s s  Spectrometry Center, Department of Chemistry, U B C . T h e mass spectrum  was  d e t e r m i n e d u s i n g c h e m i c a l ionization b y the addition o f a m m o n i a to the test sample. Ultraviolet spectrum ( U V ) The U V spectrum of the c o m p o u n d w a s recorded with a Varian Gary  3  S p e c t r o p h o t o m e t e r i n the r a n g e 4 0 0 to 8 0 0 n m . A solution c o n t a i n i n g 0.1 m g the isolated c o m p o u n d sample in 10 m l o f methanol was used for the  of  U V  measurement. Fourier transform infrared spectrum The FTIR  (FTIR)  spectrum o f the isolated c o m p o u n d was obtained with a Perkin-  Elmer 1600 Spectrophotometer over the range  4000 c m  -  1  to 500 c m  -  1  . A  pellet w a s m a d e b y m i x i n g the c o m p o u n d (1 m g ) w i t h p o t a s s i u m b r o m i d e  K B r (200  m g ) a n d c o m p r e s s i n g the resulting p o w d e r at 2 5 0 0 0 p s i i n a 1 c m d i a m e t e r pellet press. Nuclear magnetic resonance ( N M R ) spectrum The proton N M R spectrum o f the c o m p o u n d was obtained using a Bruker W H - 4 0 0 spectrometer, D e p a r t m e n t o f C h e m i s l r y , U B C . T h e c o m p o u n d (6 was dissolved in deutero-acetone in a 5 m m thin-walled N M R glass tube.  m g )  a  41  C h e m i c a l shifts w e r e reported i n p p m d o w n f i e l d f r o m the trimethylsilane ( T M S ) reference  3.1.2.3  standard.  Reactivity with copper  solutions  To determine under what conditions the dark coloured reaction products w e r e produced, 0.1034 g o f the purified white solid was dissolved in 100 m l methanol and aliquots reacted with 0.0034 M  of  c o p p e r solutions at different p H ' s .  T h e copper solutions w e r e copper sulphate in distilled water (pH=6);  copper  carbonate in C C A (pH=3); copper sulphate dissolved in 2 % a m m o n i u m hydroxide solution (pH=10.5); and copper sulphate in excess sodium hydroxide (pH=10). T h e reaction of 2 % a m m o n i u m hydroxide alone, was also  solution examined.  Since the reaction with copper sulphate in a m m o n i u m hydroxide p r o d u c e d a b l a c k precipitate, it w a s r e p e a t e d . A  14 m l aliquot o f a 1.5% a m m o n i a c a l  copper  sulphate solution w a s a d d e d to 304 m g (1.0 m m o l ) o f the w h i t e solid dissolved anhydrous methanol (20 ml). After four hours the original white solid w a s l o n g e r d e t e c t e d d u r i n g T L C a n a l y s i s . It i n d i c a t e d t h a t a l m o s t a l l w h i t e  in  no  solid  c o m p o u n d reacted with copper ions a n d f o r m e d the precipitate. T h e black precipitate w a s filtered, w a s h e d three t i m e s w i t h distilled w a t e r a n d o v e n d r i e d at 105 ° C (364 mg). T h e FTIR spectrum o f the black precipitate was  A UV-Visible  recorded.  spectral analysis i n the range 4 0 0 to 800 n m w a s  performed  o n solutions prepared b y combining 1 m l o f a 2 % methanol solution o f the solid, with 1 m l o f each copper  solution.  white  42  3.2  Fixation of ammoniacal copper preservative in wood  3.2.1 Sample preparation Sample for FTIR a.  analysis  W o o d  T h e b l o c k s ( 1 5 X 2 0 X 3 0 m m ) o f p o n d e r o s a p i n e (Pinusponderosa  Laws.)  sapwood were prepared f r o m kiln dried lumber. T h e blocks were soaked  in  distilled water under reduced pressure for 30 m i n , w h i c h r e m o v e d the air f r o m w o o d . T h e v a c u u m w a s released to the atmosphere to force the water to enter w o o d . B l o c k s w h i c h w e r e left to soak overnight for c o m p l e t e  the the  impregnation.  T h e b l o c k s w e r e m o u n t e d i n am i c r o t o m e i n o r d e r t o p r o d u c e 4 0 u j n t h i n earlywood sections, along the tangential surface. During nticrotoming water b r u s h e d o n the w o o d surface to a v o i d drying. T h e tlvin w o o d sections  was  were  f l a t t e n e d i n ap e t r i d i s h t o a l l o w t o a i r d r y . b. Cellulose: Pure cellulose p o w d e r  (Avicel™)  c. H o l o c e l l u l o s e : H o l o c e l l u l o s e ( a m i x t u r e o f c e l l u l o s e a n d w a s p r e p a r e d a c c o r d i n g to the f o l l o w i n g p r o c e d u r e (Paszner,  hemicellulose)  1994).  Ponderosa pine s a p w o o d samples w e r e cut into thin chips a n d g r o u n d with a W i l e y mill u n t i l the s a w d u s t w o u l d p a s s t h r o u g h a2 0 m e s h screen. A 10 g portion o f the w o o d m e a l was placed in a n extraction thimble, a n d covered with a c o n e s h a p e d filter paper. T h e thimble w a s p l a c e d i n aSoxhlet extractor, a n d  the  s a w d u s t w a s e x t r a c t e d w i t h a2:1 m i x t u r e o f e t h a n o l to b e n z e n e f o r 2 4 h o u r s . A 2 g sample o f air dried extractive free ponderosa pine w o o d m e a l w a s placed in a tube. T h e n 28 m l o f buffer solution a n d 12 m l o f 2 0 % s o d i u m chlorite  solution  w e r e a d d e d . T h e tube containing the m i x t u r e w a s p l a c e d i n aconstant  temperature  s h a k i n g i n c u b a t o r (at 5 0 ° C ) overnight. T h e c o n t e n t s o f t h e t u b e w e r e c o o l e d a n d t r a n s f e r r e d to am e d i u m tared, crucible. T h e solid w a s w a s h e d first w i t h 1 % acetic acid, a n d t h e n  porosity, with  43  acetone. T h e samples w e r e conditioned in the C T Hr o o m for 1 week, before  oven  d r y i n g at 105 ° C . d. K l a s o n lignin: Air-dried extractive-free ponderosa pine w o o d m e a l u s e d to prepare K l a s o n lignin (Paszner, 1994). T h e modification i n v o l v e d  was  the  s e c o n d a r y hydrolysis step. A f t e r dilution w i t h distilled water the concentration sulfuric acid w a s r e d u c e d to 3 % . T h e solution w a s autoclaved u n d e r  of  steam  p r e s s u r e o f 1.5 b a r at 1 2 7 . 5 ° C f o r o n e h o u r . T h e insoluble material w a s a l l o w e d to settle overnight, before  carefully  decanting through a m e d i u m porosity filtering crucible. T h e solid w a s w a s h e d  with  distilled w a t e r a n d o v e n d r i e d at 105 ° C . e. L i g n i n m o d e l c o m p o u n d s : L i g n i n i s a c o m p l e x a n d h i g h m o l e c u l a r w e i g h t p o l y m e r b u i l t u p o n p h e n y l p r o p a n e u n i t s . It is n o t p o s s i b l e to i s o l a t e l i g n i n from  w o o d without causing s o m e structural changes. In this study a lignin m o d e l  c o m p o u n d (vanillin) containing a n ortho-methoxyl p h e n o l w a s u s e d to investigate the potential reaction b e t w e e n guaiacyl groups c o m m o n l y in lignin a n d  a m m o n i u m  hydroxide/ammoniacal copper solution. Vanillin was purchased  from  Chemical C o m p a n y . A m m o n i u m hydroxide and copper sulphate  pentahydrate  were commercial chemicals supplied b y B D H .  Aldrich  44  3 . 2 . 2  S a m p l e  t r e a t m e n t  a. R e a c t i o n w i t h a m m o n i u m h y d r o x i d e W o o d sections, lignin, cellulose and holocellulose were soaked in a  5 %  a m m o n i u m hydroxide solution or 5 % o n a copper oxide basis (Copper sulphate) 1 0 % a m m o n i a solution f o r 1 h o u r , a n d filtered. T h e filtrite w a s airdried  in  before  testing. Vanillinwas dissolved in 5 % a m m o n i u m hydroxide solution under stirring for eight hours, after w h i c h the a m m o n i a w a s r e m o v e d to p r o d u c e a residue. residue was dissolved in chloroform for gas chromatograph-mass (GC-MS)  T h e  spectrometry  analysis.  b. R e a c t i o n w i t h a m m o n i a c a l c o p p e r  solution  V a n i l l i n(lg, 0.0066 m o l ) w a s dissolved i n 20 m l 5 % a m m o n i u m h y d r o x i d e solution. T w e n t y m l of an a m m o m a c a l copper solution (0.0030 m o l of copper sulphate i n 5 % a m m o n i u m h y d r o x i d e solution) w a s a d d e d to this, d r o p w i s e ,  with  stirring. E v a p o r a t i o n o f the a m m o n i a f r o m the v a n i l l i n - a m m o n i a c a l c o p p e r solution u n d e r r e d u c e d pressure at 40°C, p r o d u c e d a g r e e n crystalline precipitate. T h e green solid w a s filtered, a n d w a s h e d w i t h distilled water to r e m o v e  excess  a m m o n i u m hydroxide until the solution attained the p H o f the distilled water  ( p H  = 6). T h e g r e e n p o l y c r y s t a l l i n e solid w a s d r i e d u n d e r v a c u u m at 4 0 ° C , w a s h e d three times w i t h ether to r e m o v e u n r e a c t e d vanillin a n d finally v a c u u m d r i e d at r o o m temperature for eight hours. A single crystal of v a m l l i n - c o p p e r - a m m o m a complex was obtained through careful recrystalization in an ammoniacal  copper  solution. I n a s e c o n d e x p e r i m e n t , 0.1 g o f the g r e e n p o l y c r y s t a l l i n e  complex  dissolved i n 2 0 m l o f 5 % a m m o n i u m h y d r o x i d e solution w a s a d d e d to 3 0 m l 0.02 M  sodium ethylenediaminetetraacetate  (EDTA)  solution to r e m o v e the  of copper  45  ions f r o m the vanillin-copper-ammonia complex. T h e residue was extracted times w i t h diethyl ether. A white solid w a s obtained u p o n evaporating the  3.3.3  three ether.  Analysis methods a. F T I R  spectroscopy  T h e I R spectra were obtained with a Perkin-Elmer 1600 over the range 4 0 0 0 c m  -  1  Spectrophotometer  to 4 0 0 c m " . A K B r pellet w a s m a d e b y m i x i n g 1  c o m p o u n d (1 m g ) w i t h p o t a s s i u m b r o m i d e ( 2 0 0 m g ) a n d c o m p r e s s i n g the p o w d e r at 2 5 0 0 0 p s i i n a 1 c m d i a m e t e r pellet  resulting  press.  b. G a s C h r o m a t o g r a p h - M a s s Spectrometry T h e GC-MS  the  (GC-MS):  s y s t e m w a s a c q u i r e d u s i n g a n H P 5 8 9 0 series II  gas  c h r o m a t o g r a p h equipped with a V G Trio 1000 mass selective detector.  T h e  samples w e r e analyzed o n a 25 meter H P - 5 capillary c o l u m n (0.2 m m I D , 0.32 film). T h e injector s y s t e m w a s m a i n t a i n e d at 2 5 0 ° C , a n d the o v e n  u m  temperature  w a s h e l d at 5 0 ° C f o r 2 m i n , a n d t h e n p r o g r a m m e d to 3 0 0 ° C at a rate o f 13°c/rnin. T h e components were identified b y c o m p a r i n g the mass spectra with spectra  from  the available library.  c. E l e m e n t a l A n a l y s i s w a s p e r f o r m e d b y C a n a d i a n M i c r o a n a l y t i c a l S e r v i c e Ltd., Delta, B . C . .T h e elemental analysis o f the green vanillin-copper-ammonia c o m p l e x w a s f o u n d to be: C , 4 7 . 8 7 % ; H , 4 . 9 2 % ; N , 6 . 8 1 % ; C u ,  16.0%;  C  15.9%.  1  6  H  2  0  N O Cu 2  6  requires: C , 48.01%; H , 5.01%; N , 7.01%; C u ,  d. M a s s spectroscopy  (FAB):  T h e Fast a t o m b o m b a r d m e n t mass spectrum o f the green solid c o m p l e x o b t a i n e d o n a K r a t o s C o n c e p t II H Q M a s s s p e c t r o m e t e r . T h e M a s s  was  spectrometry  46  center, the D e p a r t m e n t o f Chemistry, U B C . T h e i o n source w a s 8 K V a n d rate w a s 3 to 10 sec/decade. T h e m a t r i x u s e d w a s  thioglycerol.  scan  47  e. E S R  spectroscopy  T h e E S R spectra w e r e r e c o r d e d o n aB r u k e r E S - 1 6 0 spectrometer  equipped  w i t h avariable t e m p e r a t u r e unit, o p e r a t i n g at af r e q u e n c y o f 9.60 G H Z ( X - b a n d ) and 50 K H Z field modulation.  f. E l e c t r o n i c s p e c t r u m : T h e e l e c t r o n s p e c t r u m ( 2 0 0 - 2 5 0 0 n m ) w a s o n aVarian Cary 5UV-Vis-Nir quartz  recorded  spectrophotometer o n Nujol mull sample  between  plates.  g . X-ray  structure  determination  T h e X-ray single crystal structure analysis was p e r f o r m e d using a R i g a k u AFC6S  diffractometer with graphite m o n o c h r o m a t e d Mo-Ka  radiation. T h e crystal  data a n d details o f the data collection are s u m m a r i z e d i n T a b l e 3-1-1. T h e  final  unit-cell parameters w e r e obtained b y least-squares o n the setting angles for  25  reflections w i t h 29 = 39.5-43.5°. T h e intensities o f three standard reflections, m e a s u r e d every 200 reflections throughout the data collection, s h o w e d only r a n d o m fluctuations. T h e data were processed using the crystal structure p r o g r a m teXsan a n d c o r r e c t e d f o r L o r e n t z a n d p o l a r i z a t i o n e f f e c t s , a n d (empirical, based o n azimuthal scans for three  small  analysis absorption  reflections).  T h e s t r u c t u r e a n a l y s i s w a s i n i t i a t e d i n t h e n o n c e n t r o s y m m e t r i c s p a c e g r o u p P2\ the basis o f the ^-statistics a n d the Patterson function. T h i s choice w a s  confirmed  b y subsequent calculations. T h e structure was solved b y conventional heavy methods, the coordinates o f the C u a t o m being determined f r o m the function a n d those of the remaining n o n - h y d r o g e n atoms f r o m difference Fourier syntheses.  on  atom  Patterson  subsequent  T h e non-hydrogen atoms were refined with  anisotropic thermal parameters. T h e hydrogen atoms were fixed in calculated positions w i t h N / C - H= 0.99  Aa  nd  - 1.2  ^bonded atom-  Aparallel refinement  of  48  t h e r n i r r o r - i r n a g e s t r u c t u r e g a v e s u b s t a n t i a l l y h i g h e r r e s i d u a l s , t h e R a n d Rw factors ratios being 1.062 a n d 1.070, respectively. Neutral a t o m scattering  factors  (Ibers a n d Hamilton, 1974) a n d anomalous dispersion corrections w e r e taken t h e International  Tables forX-Ray  Crystallography  from  ( C r e a g h a n d McAuley,1992).  Table 3-1-1 CrystallograpHic data  Compound Formula  a  (C H 0 )2Cu(NH )2 8  •  C  1 6  7  H  3  2 0  3  CuN O 2  6  Molecular weight  399.89  Crystal color, habit  green, prism  Crystal size, mm  0.20x0.25x0.30  Crystal system  Monoclinic  Space group  P2  a, A  5.4172(9)  b,A  15.452(2)  c,A  10.4595(9)  P,deg  99.72(1)  VA  863.0(2)  Z  2  Calc!dS/cm3  X  D  1.539  F(000)  414  Radiation  Mo  [i, cm"*  13,00  Transmission factor (relative)  0.86-1.00  Scan type  co-29  Scan range, deg i n co  1.37 + 0.35 tan 9  Scan speed, deg/min  32 (up to 8 seconds)  Data collection  +h, +k, ±1  2 9  max.  d e  S  70  Crystal decay, %  Negligible  Total reflections  4225  Total unique reflections  3910  ^- merge  0.067  Reflection with I S 3 a (I)  2172  Number of variables  225  R  0.043  Rw  0.042  gof  2.32  Max A / a (final cycle)  0.001  Residual density, e/A^  -0.27, 0.73  b  50  a  Temperature 294 K , Rigaku AFC6S diffractometer, M o K  a  (1 = 0.71069 A) radiation, graphite  monochromator, takeoff angle 6.0°, aperture 6.0 x 6.0 mm at a distance of 285 mm from the crystal, stationary background counts at each end of the scan (scan/background time ratio 2:1), a ( F ) = [5r(C + 4S)]/Lp (S = scan rate, C = scan count, B = normalized background count), function minimized Zw(|F |\FC\)2 where w = 4FpW(FQ2), R = Z | | F | - | F | | / E | f | , Rw = ( E ( ^ | - | F | ) / E w | F | ) , and gof = [E QF \-\F \) /(m-n)] . Values given for R, R , and gof are based on those reflections with IS 3a(Z). 2  2  0  2  0  w  C  0  W  2  0  c  w  b for Friedel mates Okl and 0k-I; these were not averaged  0  c  2  0  1 / 2  51  3.3  To determine whether the enrichment of nitrogen in ammoniacal-copper preservative treated wood increases the decay potential  3.3.1  Sample preparation: a. T h i r t y six p o n d e r o s a p i n e s a p w o o d b l o c k s ( 1 . 9 X 1 . 9 X 1 . 9 c m )  were  v a c u u m impregnated with a m m o n i u m hydroxide solutions with concentrations 1, 5 a n d 1 0 % ( A W P A  Standard E10-91/1992). After treatment, the blocks  r e m o v e d f r o m t h e s o l u t i o n a n d a i r d r i e d o n aw i r e s c r e e n f o r 4 w e e k s a t  were  ambient  r o o m temperature to evaporate before soil testing. B l o c k s i m p r e g n a t e d distilled water w e r e u s e d as  of  with  controls.  T w o blocks f r o m e a c h g r o u p w e r e g r o u n d to 30 m e s h sawdust. A5g sawdust sample o f each group was soaked with 50 m l o f distilled water for  24  hours. T h e p H values o f the solutions w e r e m e a s u r e d using a n O r i o n M o d e l p H  520  meter. b . S o u t h e r n y e l l o w p i n e (Pinus spp.) s a p w o o d w a f e r s ( 1 0 c m X 3 . 5 c m  0.3 c m ) w e r e v a c u u m treated w i t h a m m o n i a c a l c o p p e r solutions. T h e  treating  solutions were prepared b y dissolving copper sulphate containing 0.06% ( e x p r e s s e d a s C u O ) i n 1, 5 a n d 1 0 % a m m o n i u m h y d r o x i d e s o l u t i o n s .  X  copper  After  treatment the wafers w e r e sealed i n plastic bags for one w e e k to a l l o w for  wet  c h e m i c a l fixation at a m b i e n t temperature. T h e y w e r e t h e n r e m o v e d f r o m the  bags  a n d airdried at r o o m temperature for t w o w e e k s . W a f e r s treated w i t h distilled water w e r e u s e d as  controls.  L e a c h i n g test E i g h t e e n wafers treated to e a c h c o p p e r retention a n d a m m o n i u m h y d r o x i d e concentration w e r e submerged in jars containing 300 m l o f distilled water,  and  p l a c e d i n adesiccator. T h e d e s i c c a t o r w a s e v a c u a t e d f o r 2 0 m i n u s i n g a v a c u u m  52  p u m p , after w h i c h the jars w e r e r e m o v e d f r o m the desiccator. T h e blocks s u b m e r g e d p r i o r to r e m o v a l . A f t e r 6, 24, 4 8 h o u r s a n d thereafter at 4 8  remained  hour  i n t e r v a l s f o r ap e r i o d o f t w o w e e k s , t h e l e a c h w a t e r w a s r e m o v e d a n d r e p l a c e d w i t h fresh distilled water. A t the e n d o f this leaching p e r i o d all samples w e r e air dried. E a c h wafer was s a w e d into two pieces. O n e half was used for nitrogen  and  copper analysis, while the matching half was ovendried, w e i g h e d a n d e m p l o y e d a soil-block  in  investigation.  3.2.2 Analysis of copper and C o p p e r  nitrogen in treated wafers  analysis:  Analysis o f copper retention in the wafers  from  each group, before and  leaching was carried out using an X-ray fluorescence analyzer. E a c h wafer  after  was  ground into 30 micro m e s h sawdust. T h e sawdust was compressed in a sample h o l d e r u s i n g ah a n d p r e s s . T h e f i n a l a n a l y t i c a l r e s u l t w a s g i v e n i n t e r m s o f c o p p e r oxide i n test s a m p l e (kg/m ) using a n internal c o m m e r c i a l p r o g r a m 3  from  over 125 Nitrogen  developed  standards. analysis  Nitrogen analysis was p e r f o r m e d with the K j e d a h l technique using  the  Kjeltec A u t o 1030 nitrogen analyzer. T e s t p r o c e d u r e : 0.1 g o f t h e m i l l e d s a m p l e w a s p u t i n t o aK j e l d a h l d i g e s t i o n t u b e . T o t h e w o o d s a m p l e w a s a d d e d a h a l f o f a t a b l e t o f K j e d a h l c a t a l y s t (Q1SO4 a n d T i 0 2 ) . T h e t u b e s w e r e set o n the digestion r a c k i n the h e a t i n g m a n t l e . O n c e all 12 digestion t u b e s w e r e i n place, 5m l o f 9 8 % p u r e sulfuric a c i d w a s  carefully  a d d e d to e a c h tube. A f t e r the sulfuric acid h a d b e e n added, the samples  were  heated to about 4 0 0 ° C a n d the digestion a l l o w e d to p r o c e e d for t w o hours.  T h e  endpoint for digestion was identified b y the formation o f a clear lime-green liquid w h i c h showed no effervescence. T h e digestion tubes were then r e m o v e d  from  the  53  m e t a l mantle a n d a l l o w e d to cool to r o o m temperature prior to titration. A 0.01 M HQ  solution w a s u s e d to titrate the distilled solutions. T h e Kjedahl apparatus w a s calibrated b y analysis distilled water a n d  a m m o n i u m sulfate (500 p p m ) control prior to the analysis o f the test samples.  T h e  nitrogen content w a s calculated f r o m the equation: [VO1.HCI(1)-VO1.HCI(2)] X 0 . 0 1 4 0 1 %nitrogen mass o f sample (in grams) W h e r e : VO1. Q(1) w a s c o n s u m e d f o r s a m p l e . H  Vol.  H  C  1  (2) w a s c o n s u m e d for blank control.  0 . 0 1 4 0 1 w a s af a c t o r f o r n i t r o g e n .  3.3.3 Test Method T w o sets o f samples w e r e p r e p a r e d f o r asoil j a r experiment, w h i c h largely based o n the protocol described i n the A m e r i c a n W o o d Standard (AWPA  E10-91/1992).  ( 1 2 0 F : F r . C o o k e , Madison  M u r r . Madison  Preserver's  T h r e e fungi w e r e u s e d i n this study: t w o  rot fungi a n d one white rot fungus. T h e b r o w n rot fungi were 6 9 8 ) a n d Gloeophyllum  6 1 7 ) . P. placenta  trabeum  w a s  b r o w n  Postiaplacenta  ( 4 7 D P e r s . ex F r .  is a n i m p o r t a n t d e c a y f u n g u s i n t i m b e r i n N o r t h  A m e r i c a a n d is u s u a l l y i n c l u d e d i n laboratory evaluation o f preservatives i n N o r t h A m e r i c a a n d E u r o p e . It is p a r t i c u l a r l y t o l e r a n t t o c o p p e r a n d z i n c c o m p o u n d s . G . trabeum  is c o m m o n l y f o u n d i n a b o v e g r o u n d e x p o s u r e a n d is k n o w n to b e  to p h e n o l i c a n d a r s e n i c c o m p o u n d s . It is a l s o w i d e l y u s e d as aw o o d  tolerant  destroying  test o r g a n i s m . T h e white rot fungus e m p l o y e d i n the investigation w a s versicolor  isolated  Trametes  ( L . : F r . ) .It t o o i s a c o m m o n s t a n d a r d t e s t f u n g u s a n d i s f r e q u e n t l y from  h a r d w o o d products.  54  T h e fungi w e r e g r o w n f r o m isolates in storage using a m e d i u m consisting  of  2 % m a l t extract a n d 2 % agar in petri plates. T h e m e d i u m w a s p r e p a r e d b y dissolving 5 g o f malt extract a n d 5 g o f agar in 250 m l o f distilled water.  T h e  bottle containing the m e d i u m w a s stoppered a n d a u t o c l a v e d for 2 0 m i n at kPa. A f t e r sterilization, the bottle w a s a l l o w e d to cool to 'hand-hot'  103.4  temperature  a n d the culture m e d i u m p o u r e d into the petri plates. W h e n the m e d i u m  h a d  solidified a n d cooled, the plates w e r e inoculated with the fungi. A small plug  of  f u n g a l i n o c u l u m w a s r e m o v e d f r o m the o v e r g r o w n plate u s i n g a sterile  spatula,  a n d p l a c e d i n the center o f the m e d i u m i n a petri plate. T h e culture w a s  incubated  for two weeks before being  used.  Preparation o f soil jars a n d soil block incubation Soil p u r c h a s e d f r o m V a n t r o Soil Inc., V a n c o u v e r . B . C . w a s sifted t h r o u g h a U . S .# 5 s i e v e . T o d e t e r m i n e t h e m o i s t u r e c o n t e n t o f t h e s o i l , t h r e e s a m p l e s  were  t a k e n f r o m the b a g o f soil a n d w e i g h e d . T h e y w e r e p l a c e d i n a n o v e n at 103 ° C for 24 hours, a n d the moisture content was calculated f r o m the differences  between  the original a n d ovendried weights. T h e soil moisture content w a s adjusted to 5 0 % b y a d d i n g the r e q u i r e d a m o u n t o f water to the soil a n d m i x e d ( A W P A  40-  thoroughly  Standard E10-91/1992). T h e f e e d e r strips (3 X 2 5 X 6 0 m m ) w e r e p r e p a r e d  s a p w o o d for the b r o w n rot fungi a n d  from  from  ponderosa  pine  b i r c h (Betula alleghaniensis) s a p w o o d  f o r the w h i t e rot f u n g u s . T h e role o f the f e e d e r strip is to p r o v i d e essential nutrients for the f u n g u s to colonize the w o o d a n d soil. T h e glass jars of approximately 600 m l capacity were closed with a metal lid in w h i c h a central 5 m m hole h a d been drilled. T h e hole was covered with a  25  m m d i a m e t e r m i l l i p o r e filter, w h i c h w a s g l u e d to the inside o f the lid. T h e jars w e r e filled to a p p r o x i m a t e l y h a l f their d e p t h w i t h the p r e p a r e d soil. F e e d e r  strips  55  w e r e p l a c e d carefully o n the soil surface a n d w e r e p u s h e d lightly into the soil.  So  that the top e d g e r e m a i n e d slightly higher t h a n the surface o f the soil. T h e jars w e r e sealed w i t h plastic lids a n d s t e a m autoclave sterilized at 103.4 k P a for  one  hour. T h e y w e r e a l l o w e d to cool a n d the taken to a l a m i n a r f l o w b e n c h w h e r e lids w e r e replaced w i t h the metal lids w h i c h h a d b e e n sterilized b y  the  autoclave.  T h e f e e d e r strips w e r e i n o c u l a t e d at d i a g o n a l l y opposite c o r n e r s u s i n g m m diameter plugs of fungus, taken  from  cultures actively growing  6  o n malt  agar  i n petri plates. T h e jars w e r e i n c u b a t e d at 2 2 ° C i n a f u n g a l c h a m b e r f o r three w e e k s to allow the fungus to effectively colonize the feeder strips a n d established in the  b e c o m e  soil.  There are three m a i n methods o f sterilizing w o o d blocks, g a m m a radiation, s t e a m h e a t i n g a n d e t h y l e n e o x i d e treatment. S t e a m sterilization is e a s y to u s e  and  economical. H o w e v e r , the steam treatment m a y result in evaporation o f extractives or chemicals  from  the w o o d . T h e distribution o f preservatives in the treated  samples m a y also be affected. T h e h i g h temperature m a y also b r e a k d o w n organic preservatives. G a m m a sterilization does not affect  w o o d s o m e  preservative  contribution a n d compositions in the treated w o o d . In this experiment w e  used  g a m m a radiation to sterilize the w o o d block. T h e w o o d w a s sterilized b y  exposure  to 2.5 M r a d o f g a m m a irradiation. T h i s r e q u i r e d a p p r o x i m a t e l y 48 h o u r s  of  exposure. After three w e e k s o f incubation, the feeder strips w e r e c o v e r e d w i t h fungal hyphae. T h e jars w e r e placed o n a laminar f l o w b e n c h a n d the lids w e r e  r e m o v e d  to a l l o w t w o sterilized blocks to b e p l a c e d o n the feeder strip i n e a c h soil jar. T h e r e w e r e five replicates o f e a c h test variable. T h e test variables w e r e different a m m o n i a concentrations, presence or absence o f copper, a n d  three three  species o f fungi. T h e soil jars w e r e i n c u b a t e d f o r t w e l v e w e e k s at a p p r o x i m a t e l y 25 ° C .  56  4.0  RESULTS AND  DISCUSSION  4.1  Study of extractives in Douglas-fir heartwood which is responsible for black color when treating with ammoniacal copper solution.  4.1.1  Identification of the  extractive reacting with ammoniacal copper  solution to produce a black colour T h e preliminary experiments s h o w e d that the c h e m i c a l responsible for the dark reaction with a m m o m a c a l copper solutions w a s in the  acetone-extracted  fraction from Douglas-fir heartwood. Further solvent extraction together with silica gel c o l u m n c h r o m a t o g r a p h y separation o f the extract lead to the isolation a white solid which, w h e n dissolved in methanol, p r o d u c e d the characteristic reaction with a m m o m a c a l copper  of dark  solutions.  T h e identification o f the white solid w a s revealed to b e taxifolin t h r o u g h a combination of physical and spectroscopic  analyses.  T h e R f value for the w h i t e solid o n asilica gel plate, a n d a n eluting o f h e x a n e : a c e t o n e 2:3, w a s 0.54. T h e c r e a m - w h i t e crystals p r e p a r e d f r o m a c e t o n e extract m e l t e d w i t h d e c o m p o s i t i o n at 2 3 6 - 2 3 8 ° C , w h i c h  solution the  compared  f a v o r a b l y w i t h r e p o r t e d values for taxifolin at 2 3 7 ° C ( G r a h a m a n d K u r t h , and 240-242°C (Pew,  1949)  1948).  T h e U V s p e c t r u m i n F i g . 4 - 1 - 1 s h o w e d am a x i m u m a b s o r b a n c e a t 2 8 9  n m  a n d am i n i m u m a b s o r b a n c e at 2 4 9 n m , c o n s i s t e n t w i t h t h e s p e c t r u m o f t a x i f o l i n p u b l i s h e d b y A f t ( 1 9 6 1 ) a n d M a b r y et a / . ( 1 9 7 0 ) . T h e F T I R s p e c t r u m o f t h e isolated c o m p o u n d s h o w n in Fig. 4-l-2(a) contained several characteristic w h i c h are identified in table  4-1-1.  peaks,  57  T h e proton signal obtained in the nuclear magnetic resonance spectrum  of  the w h i t e s o l i d is s h o w n i n F i g . 4 - 1 - 3 . T h e c h e m i c a l shifts d e t e r m i n e d f r o m the proton-nuclear magnetic resonance spectrum o f the white solid based u p o n a s s i g n m e n t b y M a r b y et al.  the  ( 1 9 7 0 ) a n d b y H a r b o r n e et a / . ( 1 9 7 5 ) a n d s h o w n  T a b l e 4 - 1 - 2 , m a t c h e d t h o s e i d e n t i f i e d f o r t a x i f o l i n b y M a b r y et al ( 1 9 7 0 )  in  and  M b a f o r a n d F o m u m ( 1 9 8 9 ) . T h e m a s s s p e c t r u m o f the w h i t e s o l i d is s h o w n i n F i g . 4-1-4. T h e m/e fragment pattern o f the mass spectrum was c o m p a r e d with  that  r e p o r t e d b y A u d i e r (1966). T h e p e a k at m / e = 3 2 2 resulted f r o m ions p r o d u c e d the reaction between the molecule a n d the a m m o n i a used in the  b y  chemical  i o n i z a t i o n [ M + NFLi]" ". T h e p e a k o f m / e 3 0 5 is d u e to m o l e c u l e i o n [ M + H  ] .  1  +  T t h e m o l e c u l a r w e i g h t o f the w h i t e solid is 304. O t h e r m a s s f r a g m e n t s o b s e r v e d , m/e values o f 289, 153 a n d 123, arise f r o m cleavage reaction. T h e  at  cleavage  reactions a n d ionic species are illustrated in Fig. 4-1-5. T h u s , the c o m p o u n d w a s c o n f i r m e d to b e taxifolin (3,3',4',  5,7-  p e n t a h y d r o x y f l a v a v o n e ) , the structure o f w h i c h is s h o w n i n F i g 4 - l - 6 ( a ) . T a x i f o l i n is a m a j o r p h e n o l i c extractive i n D o u g l a s - f i r , b e i n g first isolated b y in 1948.  T h e average concentration o f taxifolin i n Douglas-fir w a s f o u n d to  P e w be  1%. G a r d n e r a n d B a r t o n (1960) investigated the distribution o f taxifolin in Douglas-fir a n d f o u n d that the content in Douglas-fir h e a r t w o o d  varied  c o n s i d e r a b l y , b o t h w i t h i n a tree a n d b e t w e e n trees. T h e v a r i a n c e r a n g e d f r o m zero to 1.5 p e r c e n t . W i t h i n trees, a g e n e r a l p a t t e r n o f i n c r e a s i n g c o n c e n t r a t i o n  with  i n c r e a s i n g distance f r o m the p i t h w a s e v i d e n t i n the h e a r t w o o d . T a x i f o l i n is soluble i n h o t w a t e r ( 1 3 . 5 % at 100 ° C ) a n d relatively insoluble i n c o l d w a t e r %  at 2 5 ° C ) .  quite (0.25  58  59  Fig. 4-1-2 F T I R spectra o f a) taxifolin isolated f r o m D o u g l a s - f i r h e a r t w o o d a n d b) the b l a c k precipitate f o r m e d during the reaction o f taxifolin a n d a m m o n i a c a l c o p p e r solution. Spectra w e r e collected as K B r discs.  60  Table 4-1-1. Assignment o f absorption bands in I R spectrum o f isolated compound  Wave-number ( c m )  Assignment  -1  3400  O - H stretching vibration  1640  C = 0 stretching vibration  1430-1510  C - H bending vibration/aromatic skeletal vibration  1359-1390  O - H in plane bending vibration  1000-1250  C - O - C stretching vibration  973  = C H out o f plane deformation  750-875  C - H out-of-plane bending vibration  680  C - C out-of-plane bending vibration  61  CM  <+-( o *-> o cd  in  B co a o -*-»  <D  O  cd  <u O  -a  0  •a O  ca  r-  s:  1 g  in.  ii.  s ~ in S3  to  2 « o <u o  o o  co  CD  ca  21 .5? §  Table 4-1-2. Chemical shifts for the proton nuclear magnetic resonance spectrum o f the compound extracted from Douglas-fir heartwood  Chemical shift  Proton  (ppm)  assignment  Taxifolin > b  c  a  A-ring 5.91  H-6  5.75-5.95  5.95  H-8  5.92  6.80  H-2'  6.75  7.02  H-5'  6.88  6.80  H-6'  6.75  4.95  H-2  4.96  4.55  H-3  4.97  B-ring  C-ring  a. Harborne et al, (1975); b. Marby et al, (1970) and c. Mbafor and Fomum (1989).  63  I t h  i. 1N2  G3  I  s  a  CTi CD  r 33  ••N3 :  ,  2  0  co  r i-33  1  ' CN] j  u r- CO  \ • J  CM S3  i CM t  /3  3 3  S3  CM J  S3  f S31  CD CO CO  r S3]  CD  1  00  =f  t  CD  CD  ' H i  !  CD  33 i  00 V • • N  CD  CD  A  iT.  r-  N CD ID  X LO IN  N CD CD  X  in  X CD  in CM  o *J +J o a «-< u c o +-»  CD O cd CD  -*-»  e o *l  •a *o  F i g . 4-1-5  Diagnostic mass spectral fragmentation from white solid from Douglas-fir heartwood.  extracted  65  Fig 4-1-6 The molecular structures of taxifolin (a) and the three possible 1:1 copper complexes (b), (c) and (d).  66  4.1.2  The  nature of the  chemical complex formed between copper  solutions and taxifolin. A d d i t i o n o f a m e t h a n o l solution o f the white solid to a m m o n i u m h y d r o x i d e p r o d u c e d ap a l e y e l l o w s o l u t i o n . S i m i l a r r e a c t i o n s w e r e r e c o r d e d w h e n  copper  sulphate i n either distilled water or i n excess s o d i u m h y d r o x i d e w a s a d d e d to  the  test solution. T h e C C A solution ( p H = 3 ) caused the taxifolin solution to turn dark y e l l o w a n d p r o d u c e d ay e l l o w  precipitate after ten minutes. W h e n  a m m o m a c a l  c o p p e r sulphate w a s a d d e d to the test solution, the colour c h a n g e d f r o m  light  y e l l o w t o d a r k b r o w n a n d ab l a c k s o l i d s l o w l y f o r m e d . I f t h e r e a c t i o n w a s  m a d e  sequentially, w i t h c o p p e r sulphate b e i n g a d d e d to the taxifolin s o l u t i o n first, a black p r o d u c t w a s f o r m e d o n l y w h e n the a m m o n i u m h y d r o x i d e w a s a d d e d to  the  mixture. T h e rate o f formation o f the black precipitate w a s slower than w h e n  an  ammoniacal copper sulphate solution was  used.  Confirmation o f the visual results w a s m a d e f r o m visible spectra recorded for each o f the solutions. W h e n the methanol solution o f taxifolin w a s m i x e d a m m o n i a c a l c o p p e r sulphate, a n a b s o r p t i o n a p p e a r e d at 5 8 0 n m after 2 0  minutes  (Fig.4-1-7) w h i c h increased with time. W h e n similar studies were m a d e with copper solutions, n o characteristic peaks w e r e observed (Fig. 4-1-8).  These  observations c o n f i r m e d that o n l y a m m o n i a c a l c o p p e r solutions o f c o p p e r salts reacted w i t h taxifolin to p r o d u c e the dark colour.  with  other  67  O C  60 min  ro  %—  o  X) CO  <D > _ro  V DC  400  500  600  700  Wavelength (nm)  Fig. 4-1-7  Changes in the visible spectra of taxifolin in methanol to which was added ammoniacal copper solution.  68  Fig. 4-1-8  T h e v i s i b l e s p e c t r a of t a x i f o l i n p l u s a ) C C A s o l u t i o n , b ) c o p p e r sulphate in excess s o d i u m h y d r o x i d e , c) c o p p e r sulphate i n distilled water, a n d d) 2 % a r n r n o n i u m h y d r o x i d e solution, 60 m i n u t e s after mixing. •  69  In flavonones,  c o p p e r c a n b e chelated at either the 3 - h y d r o x y a n d 4 - k e t o o r  hydroxy and 4-keto groups, fonriing a 6-membered  5-  or 5-membered ring (Fig.  6 b a n d c) (Jurd, 1962; S a k a m a t o a n d T a k a m u r a , 1978; T a k a m u r a a n d  Sakamato,  1978). In taxifolin the reactivity o f the proton o n the 5-hydroxy group  conjugated  w i t h b e n z e n e r i n g A , is greater t h a n that o n the 3 - h y d r o x y l g r o u p , so that  copper  c h e l a t i o n to the A r i n g is anticipated. T h i s reactivity o f the 5 - h y d r o x y l g r o u p confirmed b y Porter and Markham  4-1-  was  (1972) w h o demonstrated that metal ions  were  preferentially chelated at this p o s i t i o n i n d i h y d r o f l a v o n o l s . F o l l o w i n g initial c o m p l e x formation involving the 5-hydroxyl a n d the ketone groups, reaction the 3 - h y d r o x y l g r o u p c a n b e e l i m i n a t e d . H o w e v e r , f u r t h e r c o o r d i n a t i o n is t h r o u g h t h e 3' a n d 4' h y d r o x y l g r o u p s o f t a x i f o l i n ( F i g . 4 - l - 6 d ) . T h e  possible  3-hydroxyl  a n d 7-hydroxyl groups are either not involved in bonding, or participate intermolecular bonding, with the formation o f a polymeric  with  in  structure.  During reaction with ammoniacal copper sulphate solution, taxifolin a black complex, which was insoluble in both water and c o m m o n organic  formed solvents,  s u c h as diethyl ether, ethyl alcohol, c h l o r o f o r m a n d acetone. T h i s i m p l i e d that c o p p e r w a s strongly b o u n d to the taxifolin. T h e F T I R spectra o f the  the  taxifolin  extracted f r o m Douglas-fir heartwood a n d the reaction product f o r m e d  with  a m m o n i a c a l copper sulphate are s h o w n in F i g 4-l-2b. A n extremely b r o a d b a n d 3500 c m  -  1  suggested that s o m e o f the h y d r o x y l groups o n taxifolin m a y  be  involved in chelate formation or intermolecular H-bonding, in the copper T h e p e a k at 1 6 4 0 c m " c m  -  1  1  formation.  complex.  d u e to the k e t o n e b o n d i n g i n taxifolin w a s shifted to  in the black solid, confirming the involvement o f this group during  at  1600  complex  70  Two  questions r e m a i n e d u n a n s w e r e d . T h e y w e r e a) the role o f a m m o n i a i n  c o m p l e x formation a n d b) the nature o f the molecular structure o f the  copper  taxifolin complex. B a s e d o n the results o f similar reactions w i t h other  copper  containing solutions, the formation o f the black solid appeared to require the presence o f b o t h the c o p p e r a n d a m m o n i a , since other c o p p e r solutions failed to produce a black coloured product, even under alkaline conditions.  Similarly,  a m m o n i u m hydroxide alone did not cause a coloured reaction. Elemental  analysis  of the black solid confirmed the presence o f nitrogen. T h e a m m o n i a m a y  be  retained in the copper taxifolin product, either through the formation o f a dianimine c o m p l e x [Cu(NH3)2.taxifolin] or through the formation o f a n g r o u p t h r o u g h a reaction w i t h the taxifolin, w h i c h then chelated to the  imino copper.  H o w e v e r , since the - C = N stretching b a n d occurs in the s a m e region o f the s p e c t r a as the c a r b o n y l g r o u p , it w a s n o t p o s s i b l e to u s e the F T I R  FTIR  s p e c t r u m to  c o n f i r m this reaction. From  a review o f the literature o f the formation o f copper flavanoid  c o m p l e x e s , it is u n c l e a r w h e t h e r t h e r a t i o o f c o p p e r to t a x i f o l i n w o u l d b e 1:1 1 : 2 . D e t t y et al.  ( 1 9 5 5 ) h a v e r e p o r t e d t h a t c o p p e r f o r m e d a 1:1 c o m p l e x  d i h y d r o q u e r c e t i n (taxifolin) at p H 10.0 a n d a 1:2 c o m p l e x at p H o f Conversely, Takamura  or  with  6.5.  a n d S a k a m o t o ( 1 9 7 8 ) s u g g e s t e d that at a h i g h p H , the  f o r m a t i o n o f a 1:2 c o m p l e x is e x p e c t e d , a n d i d e n t i f i e d t h e m a g n i t u d e o f t h e in the m a x i m a i n absorption spectra. T h e y also noted that the  shifts  quercetin-copper(II)  system could not be properly characterised because o f catalytic oxidation  of  quercetin b y copper under alkaline conditions. Delaporte and M a c h e i x (1972)  have  r e p o r t e d that the r e d u c i n g c h a r a c t e r o f the f l a v a n o l s is e n h a n c e d b y a c t i v a t i o n  of  t h e h e t r e o c y c l i c r i n g , w h e n h y d r o x y l g r o u p s a r e i n t r o d u c e d at t h e 5 a n d 4' positions o f r i n g A a n d B , respectively. H o w e v e r , s u c h o x i d a t i o n is n o t  anticipated  71  in the taxifolin-copper complexes i n the current study, since the s a m e authors  have  o b s e r v e d that n o reduction occurs w h e n the heterocyclic g r o u p is h y d r o g e n a t e d the 2 a n d 3  at  positions.  T h e analytical results c o u l d n o t b e resolved to c o n f i r m a  coppentaxifolin  ratio o f either 1:1 o r 1:2, b u t w e r e m o r e c o n s i s t e n t w i t h a 3:2 c o m p l e x  containing  complexed nitrogen. T h e elemental analysis o f the black solid yielded the f o l l o w i n g results. F o u n d : C : 38.29, H : 3.48, N : 6.74, C u : 21.04. Calculated: C : 39.96, H : 3.35, N : 6.26, C u :21.12, based u p o n the  molecule  [Taxifolin]2.Cu3.(NH3)4.2H20. Further research is r e q u i r e d to better the black copper  complex.  characterize  72  4.2  Fixation mechanism of ammoniacal copper wood preservatives  4.2.1  Reaction with a m m o n i u m hydroxide  4.2.1.1  solution:  W o o d The effect o f a m m o n i u m hydroxide o n ponderosa pine s a p w o o d  treated  with a m m o n i u m hydroxide was observed b y c o m p a r i n g the F T I R spectra  of  section f r o m treated w o o d with those of untreated w o o d (Fig. 4-2-1). T h e peak 1730 cm  -  1  at  , due to c a r b o n y l or c a r b o x y l groups vibration, decreased i n intensity,  w h i l e that at 1654 c m  -  1  w h i c h represents amide functionality was slightly  after a m m o n i u m h y d r o x i d e treatment than for the untreated w o o d . T h i s indicate that the carbonyl a n d carboxyl groups in w o o d h a d reacted w i t h t o f o r m a m i d e c o m p o u n d s ( W a n g , et al.  1 9 6 7 ; K a p l u n o v a , et al.,  stronger  m a y a m m o n i a  1986).  In order to e x a m i n e the effect o f a m m o n i a concentration o n the  possible  formation o f amide compounds, three a m m o n i u m hydroxide solutions (5%, a n d 25%) w e r e reacted with w o o d , a n d the treated w o o d e x a m i n e d b y spectroscopy. T h e F T I R p e a k at 2 9 1 0 c m  -  1  1 0 %  FTIR  (carbon-hydrogen stretching vibration)  w a s u s e d a s a n i n t e r n a l s t a n d a r d ( O s t m e y e r , et al, 1 9 8 9 ) t o e n s u r e b e t w e e n  sample  stability. T o c o m p a r e the spectra o f different samples, the p e a k area ratio o f the p e a k at 1 6 5 4 c m  -  1  a n d that at 2 9 1 0 c m  -  1  was used. This reduced the influence  sample heterogeneity, w h i c h m a y p r o d u c e variations i n signal energy as well baseline errors. T h e peak base line was d r a w n f r o m the point o f transmittance one side o f the p e a k to the point o f transmittance o n the other side o f the ( O s t m e y e r , et al,  1989).  peak  of as on  73  74  T h e r e s u l t s o f t h e p e a k r a t i o ( a m i d e :C H ) a n a l y s i s a r e e x p r e s s e d i n T a b l e 4 - 2 - 1 .  Table 4-2-1  P e a k area ratio o f amide/salt against carbon-hydrogen A m m o n i a  Ratio (1654 c n r V 2 9 1 0  concentration  Control  0.42  5 %  0.68  1 0 %  0.73  2 5 %  0.91  T h e peak ratio increased with increasing a m m o n i a  cm-1)  concentration,  suggesting that the formation o f a m i d e c o m p o u n d s increased w i t h a m m o n i a  stretching  increasing  concentration.  4.2.1.2 Cellulose After soaking in a m m o n i u m hydroxide solution the FTIR spectrum o f the cellulose s h o w e d n o obvious change c o m p a r e d with untreated cellulose. suggested that after treating w i t h a m m o n i u m h y d r o x i d e solution, w h e n  This a m m o n i a  h a d e v a p o r a t e d , the c e l l u l o s e r e m a i n e d u n c h a n g e d c h e m i c a l l y . T h i s o b s e r v a t i o n is in g o o d agreement w i t h Heuser's observation (1946), w h o reported that  the  addition of aqueous ammonia, even in concentrated f o r m (23-28 per cent) to h a v e n o effect o n cellulose  seemed  chemically.  4.2.1.3 Holocellulose A f t e r t r e a t i n g w i t h a m m o n i u m h y d r o x i d e s o l u t i o n , ac o m p a r i s o n o f t h e FTIR  spectra o f the untreated a n d treated holocellulose (Fig. 4-2-2) s h o w e d  the p e a k s at 1 7 3 4 c m  -  1  and 1250 c m  -  1  disappeared. S i n c e the p e a k at 1734  that c n r  represented carbonyl or carboxyl groups i n holocellulose, the loss o f this p e a k  1  75  confirmed that the carboxyl ( - C O O H )  h a d reacted w i t h a m m o n i a to f o r m a n  amide  c o m p o u n d o r a n a m m o n i u m salt. T h e f o r m a t i o n o f a n a m m o n i u m salt w o u l d  result  in a shift o f the p e a k f r o m 1734 c m  -  1  to a p p r o x i m a t e l y 1600 c m  -  1  (Zhbankov,  1966; Bellamy, 1958). In addition, a portion o f the reacted hemicellulose  was  d i s s o l v e d i n a m m o n i u m h y d r o x i d e solution, since the intensities at p e a k s at  1250,  1165, and 1056 c m  1988).  -  w h i c h r e p r e s e n t h e m i c e l l u l o s e d e c r e a s e d . ( K u o et al,  1  T h e solid w h i c h w a s o b t a i n e d f r o m the filtrate o f treated holocellulose  after  evaporating under v a c u u m was examined b y FTIR. T h e spectrum (Fig. 4-2-3) s h o w e d a strong n e w p e a k at 1 6 7 0 c m  -  1  . T h i s b a n d corresponds to a m i n e  a m i d e b a n d . T h e intensity o f the p e a k at 1 4 0 2 c m - 1 d u e to C - N stretch,  and increased  in the spectrum. T h i s observation confirmed that a m m o n i a c a n react with carbonyl g r o u p s present i n hemicellulose to f o r m a m i d e functional g r o u p s i n w o o d . T h e loss of b a n d of 1250 cm  -  1  , w h i c h represents C - O - Cv i b r a t i o n m a y b e e x p l a i n e d b y  the  hydrolysis o f the ester under the alkali condition, resulting the rupture o f the C - O C  bonding.  4.2.1.4  Lignin W h e n the F T I R spectrum o f a m m o n i u m hydroxide treated lignin  c o m p a r e d w i t h that o f untreated lignin, the p e a k at 1730 c m  -  1  was  was eliminated  the a m m o n i u m h y d r o x i d e treatment. T h e anticipated p e a k at 1650 c m  -  1  , due  b y to  f o r m a t i o n o f a n a m i d e g r o u p , w a s n o t o b s e r v e d . O n e p o s s i b l e r e a s o n is that K l a s o n l i g n i n is less reactive a n d there is a n a b s e n c e o f h y d r o x y l a n d c a r b o n y l g r o u p s ( B r a u n s , 1 9 5 2 ) . A n o t h e r e x p l a n a t i o n is that the p e a k is n o t visible d u e to  overlap  b y the strong b e n z e n e r i n g v i b r a t i o n at 1 6 0 0 c m  difference  -  1  . However, no obvious  in the spectra w a s observed i n other frequencies after treating w i t h hydroxide  solution.  a m m o n i u m  2000  1500  1000  500  Wave numbers ( c m ) -1  Fig 4-2-2  IR spectra of holocellulose before (lower) and after (upper) ammonium  hydroxide treatment.  77  78  One question w h i c h m a y be raised concerning the interpretation o f the peak 1654 cm  -  1  , i n t e r m s o f a m i d e v i b r a t i o n , is that this r e g i o n o f the F T I R  v e r y c o m p l e x , a n d m a y contain a n unresolved p e a k d u e to the C - 0  at  s p e c t r u m is  stretching  frequency.  4.2.2  Reaction with a m m o n i a c a l copper  solutions  FTIR spectrum of a m m o m a c a l copper solution treated w o o d sample  was  s i m i l a r to t h a t o f a m m o n i u m h y d r o x i d e - t r e a t e d w o o d . It is k n o w n t h a t E S R spectral results have indicated that copper-nitrogen b o n d e d c o m p l e x e s are f o r m e d in a m m o m a c a l copper treated w o o d (Ruddick, 1992b). T h e position o f the absorption peaks s h o w e d n o substantial shift i n f r e q u e n c y for the c o p p e r  FTIR complex  c o m p a r e d with the a m m o n i u m hydroxide treated w o o d . T h e I R measurements not materially assist the identification o f the c o m p l e x  do  formation.  The FTIR spectrum of ammoniacal-copper treated cellulose showed  no  o b v i o u s c h a n g e , c o m p a r e d w i t h t h a t o f u n t r e a t e d c e l l u l o s e . It s u g g e s t e d t h a t reaction between cellulose and ammoniacal copper must be very weak. o b s e r v a t i o n i s i n a g r e e m e n t w i t h t h e E S R r e s u l t s ( R u d d i c k et al.,  This  1992b).  holocellulose a n d lignin were reacted with an a m m o n i a c a l copper solution, FTIR  spectra showed a similar pattern of a m m o n i u m  holocellulose or lignin.  hydroxide-treated  W h e n the  79  4.2.3  Reaction of ammonium hydroxide/ammoniacal copper solution with lignin model compound  4.2.3.1 Reaction of vanillin with ammonium hydroxide solution In order to better u n d e r s t a n d the reaction b e t w e e n w o o d a n d v a n i l l i n , al i g n i n m o d e l c o m p o u n d , w a s u s e d to c o n f i r m t h e a b o v e  a m m o n i a , reaction.  V a n i l l i n c o n t a i n s am e t h o x y p h e n o l w i t h a c a r b o n y l g r o u p . T h e r e a c t i o n p r o d u c t s A b o u t 1.5% of 4-hydroxy-3-methoxy-benzonitrile  were analyzed using GC-MS.  w a s i d e n t i f i e d i n t h e r e a c t i o n p r o d u c t s ( F i g . 4-2-4). T h i s m o l e c u l e c a n b e f r o m a n a m i d e b y r e m o v a l o f water ( M e r c k , 1983), as described b y the  R - C O N H  2  derived  equation.  H 0  -> R - C = N +  2  T h e o b s e r v a t i o n o f the nitrile c o m p o u n d , as o n e o f the r e a c t i o n p r o d u c t s , is strongly supportive o f the f o r m a t i o n o f s o m e a m i d e o r a m i n e c o m p o u n d d u e to reaction b e t w e e n ac a r b o n y l g r o u p i n w o o d a n d  the  a m m o n i a .  T h e above results suggested that the s o m e fixation o f nitrogen in a m m o n i u m hydroxide-treated w o o d m a y be achieved through the reaction  of  a m m o n i a with either carbonyl or carboxyl groups in hemicellulose a n d lignin in w o o d , w i t h the f o r m a t i o n o f a m i d e a n d i m i n e c o m p o u n d s , as w e l l as salts. T h e possible reactions m a y b e e x p r e s s e d as Wood-COOH  follows:  +NH4OH - > W o o d - C O O N H  W o o d - C O O N H  4  -> W o o d - C ^ N  4  +  + 2H 0 2  W o o d - C = 0 + NH4OH - > W o o d - C = N H +  H 0 2  H 0 2  a m m o n i u m  80  UG  LAB-BftSE  The TR10-1 GC-HS Data System lnstroKntHrioieeO  XIES 11  IOO-  193536 149 112  29  18.93  •/.rs  \  16,09 8- 1  1——i  i  i  i 10,  100-  i  v.  i— —i 1  93  i ™^  71591888 TIC 111  /.rs-  o |Hlti  11  £.0  8.0  18. e  •  1  12.8  i  i 14.1'  It.  lOOl  «°  20.0  18.0  ' 22.8  KBS  POE5 759 (11.325)  ' 24.8  " 26.8  28.8  48 Hits : 4B Searched 74752  134 149 150  186  44 5,  •/.rs •)  II  287  F:575 ' 8887:B'DO0HITRILE. 4-HYDROXY—3-HETHOXy-  255  1<36 150  •/.rs  «/z  0  15 26  150  38  280  258  CH-  HO' .wvvvvvvwvvvvv vV^\/v'.'Wv«'vwvWWv wWWW>)v l  Fig 4-2-4 GC-MS hydroxide.  l  • \-  W>MA)WvWW^VVWWWWVVWVV  spectrum of a reaction product of vanillin with  a m m o n i u m  81  A l t h o u g h carboxylic acids containing fewer than five carbon atoms soluble in water, m a n y other carboxylic acids, especially the lignin type  are  carboxylic  acids of high molecular weight, are not appreciably soluble in water (Preston Jin, 1991).  and  82  4.2.3.2 Reaction of vanillin with ammoniacal copper solution During reaction with an aqueous ammoniacal copper sulphate  solution,  vanillin f o r m e d ag r e e n water-insoluble c o m p l e x u p o n evaporation to  dryness.  This complex was insoluble in both water and c o m m o n organic solvents  although  it w a s f o u n d to b e slightly s o l u b l e i n D M S O .  was  T h e nature of the c o m p l e x  characterized using X-ray crystallography, FTIR  X-ray  structural  and E S R .  examination:  T h e s t r u c t u r e o f the c o m p l e x d e t e r m i n e d b y X - r a y c r y s t a l l o g r a p h y is c o m p r i s e d o f a c e n t r a l c o p p e r (II) i o n b o n d e d t o t w o v a n i l l i n a n d t w o  a m m o n i a  molecules. T h e perspective v i e w o f the c o m p l e x with n u m b e r i n g system  is  presented in F i g . 4-2-5. In the complex, both the m e t h o x y a n d phenolic  oxygen  a t o m s o f each guaiacyl unit coordinate to the copper, together with  nitrogen  f r o m t w o a m m o n i a m o l e c u l e s to f o r m asix c o o r d i n a t e d m o l e c u l e . T h e unit cell contains two symmetrically related complexes.  T h e atomic coordinates  equivalent isotropic thermal parameters are presented in Table 4-2-2,  and while  selected inter-atomic b o n d distance a n d angles are listed in T a b l e 4-2-3  and  4-2-4  respectively. The c o p p e r a t o m displays adistorted octahedral coordination.  T h e  C u - 0  ( p h e n o l i c o x y g e n a t o m s ) a t c a . 1 . 9 7 A a n d t h e N - 0 ( a m m o n i a n i t r o g e n ) a t ca. 2.02 A f o r m asquare plane a r o u n d the central copper. T h e very  distorted  o c t a h e d r a l c o n f i g u r a t i o n is c o m p l e t e d b y the C u - 0 ( m e t h o x y o x y g e n a t o m s ) ca  at  2.38 A w h i c h are c o o r d i n a t e d at a n angle a b o u t 7 5 ° to the p l a n e , at a greater  distance than the in-plane C u - 0 (phenolic) bonds. T h e C u - N b o n d lengths 2.014  of  a n d 2 . 0 3 4 A a r e t y p i c a l o f c o p p e r ( I I ) n i t r o g e n b o n d l e n g t h s ( C o u g h l i n , et  al., 1 9 8 4 ) . T h e p l a n a r C u - 0 b o n d l e n g t h s o f 1 . 9 7 2  and 1.969 Aand longer  axial  83  Cu-0  lengths of 2.371  and 2.388 A are consistent with those observed for  d i s t o r t e d o c t a h e d r a l s t r u c t u r e s ( H o b s o n et ah,  1973). T h e C u - 0  other  (hydroxyl)  d i s t a n c e s a r e s h o r t e r t h a n t h o s e o f C u - 0 ( m e t h o x y l ) . T h i s is d u e to the  difference  b e t w e e n the electron density o f h y d r o x y l o x y g e n (rather ionic) a n d that  of  m e t h o x y l o x y g e n (neutral). T h e differences b e t w e e n the two C u - N b o n d  lengths  a n d the t w o C u - 0 (phenolic) b o n d lengths w e r e not statistically  significant.  In each unit h y d r o g e n b o n d i n g occurs between the two adjacent  complexes  through the carbonyl and h y d r o x y l o x y g e n atoms a n d h y d r o g e n o n the T h e hydrogen b o n d distances and angles are given in Table 4-2-5.  a m m o n i a .  T h e  hydrogen-oxygen intermolecular b o n d distances are between 2.09-2.51 A . strong h y d r o g e n bonding arises  from  the d e r e a l i z a t i o n o f electron to  carbonyl o x y g e n f r o m the conjugated benzene ring, resulting in  This  the  greater  electronegativity o n the o x y g e n atoms. A packing d i a g r a m has b e e n depicted Fig.  in  4-2-6.  T h e structure clearly s h o w s that the a m m o n i a h a d not reacted with the vanillin. T h i s is c o n s i s t e n t w i t h the i n v e s t i g a t i o n o f the r e a c t i o n s o f the c o m p l e x EDTA,  during w h i c h the vanillin copper c o m p l e x was destroyed. T h e  solid p r o d u c e d w a s identified as vanillin b y F T I R  spectroscopy and  with white  GC-MS.  T h i s c o n f i r m e d that the nitrogen w a s not directly b o n d e d to vanillin, suggesting instead that t w o a m m o n i a ligands o f the tetrammine c o p p e r c o m p l e x are  replaced  b y copper-oxygen bonding f r o m hydroxyl and methoxyl groups in vanillin during the c o m p l e x  formation.  84  H 1 0  Fig, 4-2-5 Perspective v i e w of Cu(D)-bis(vanillmato)bis(aimn with the atomic numbering; 3 3 % probability thermal ellipsoid are s h o w n for the n o n hydrogen atoms.  T a b l e 4-2-2. A t o m i c c o o r d i n a t e s a n d  Beq  X  y  z  Cu(l)  0.4061(1)  0.4928  0.18895(5)  2.379(9)  0(1)  0.6304(8)  0.5725(3)  0.1165(4)  2.80(9)  0(2)  0.2368(6)  0.5015(4)  -0.0350(3)  3.77(8)  0(3)  0.2540(7)  0.6388(3)  -0.4857(3)  3.69(9)  0(4)  0.1811(7)  0.4135(3)  0.2620(4)  2.70(8)  0(5)  0.5863(6)  0.4777(3)  0.4125(3)  3.23(9)  0(6)  0.608(1)  0.3115(4)  0.8502(5)  6.9(2)  N(l)  0.1929(10)  0.5937(3)  0.2254(5)  2.9(1)  N(2)  0.6205(10)  0.3919(3)  0.1477(5)  3.0(1)  C(l)  0.5757(9)  0.5978(3)  -0.0045(5)  2.28(10)  C(2)  0.3687(9)  0.5618(3)  -0.0916(4)  2.4(1)  C(3)  0.3155(9)  0.5861(4)  -0.2192(4)  2.6(1)  C(4)  0.462(1)  0.6472(4)  -0.2666(6)  2.8(1)  C(5)  0.633(1)  0.6852(4)  -0.1848(5)  2.8(1)  C(6)  0.7153(10)  0.6617(4)  -0.0547(5)  2.8(1)  C(7)  0.413(1)  0.6722(4)  -0.4046(5)  2.8(1)  C(8)  0.0349(10)  0.4578(4)  -0.1109(6)  3.5(1)  C(9)  0.2341(8)  0.3858(3)  0.3832(4)  2.19(10)  C(10)  0.4560(9)  0.4177(3)  0.4688(4)  2.3(1)  C(ll)  0.5149(10)  0.3871(4)  0.5923(5)  2.7(1)  C(12)  0.365(1)  0.3260(4)  0.6405(6)  2.5(1)  C(13)  0.147(1)  0.2965(3)  0.5594(5)  2.8(1)  C(14)  0.0852(9)  0.3262(4)  0.4332(5)  2.6(1)  C(15)  0.427(1)  0.2928(5)  0.7706(6)  4.3(2)  C(16)  0.7862(8)  0.5172(3)  0.4816(6)  3.7(1)  A t o m  B  eq  86  Table 4-2-3. Selected bond lengths (A) for vanillin-copper-ammonia complex  A t o m  A t o m  Distance  A t o m  A t o m  Distance  Cu(l)  0(1)  1.969(4)  Cu(l)  0(2)  2.371(3)  Cu(l)  0(4)  1.972(4)  Cu(l)  0(5)  2.388(3)  Cu(l)  N(l)  2.014(5)  Cu(l)  N(2)  2.034(5)  0(1)  C(l)  1.310(6)  0(2)  C(2)  1.368(6)  0(2)  C(8)  1.410(6)  0(3)  C(7)  1.216(7)  0(4)  C(9)  1.322(6)  0(5)  C(10)  1.359(6)  0(5)  C(16)  1.343(6)  0(6)  C(15)  1.211(9)  C(l)  C(2)  1.433(7)  C(l)  C(6)  1.398(7)  C(2)  C(3)  1.369(6)  C(3)  C(4)  1.380(7)  C(4)  C(5)  1.394(9)  C(4)  C(7)  1.474(7)  C(5)  C(6)  1.391(7)  C(9)  C(10)  1.458(7)  C(9)  C(14)  1.383(7)  C(10)  C(ll)  1.363(7)  C(ll)  C(12)  1.394(7)  C(12)  C(13)  1.407(8)  C(12)  C(15)  1.439(9)  C(13)  C(14)  1.384(7)  87  Table 4-2-4 Selected bond angles (°) for vardllin-copper-ammonia complex  A t o m  A t o m  A t o m  Angle (°)  A t o m  A t o m  A t o m  Angle (°)  O(l)  Cu(l)  0(2)  75.2(2)  O(l)  Cu(l)  0(4)  179.7(2)  0(1)  Cu(l)  0(5)  105.1(1)  O(l)  Cu(l)  N(l)  90.0(2)  0(1)  Cu(l)  N(2)  89.2(2)  0(2)  Cu(l)  0(4)  104.9(2)  0(2)  Cu(l)  0(5)  177.2(2)  0(2)  Cu(l)  N(l)  90.3(2)  0(2)  Cu(l)  N(2)  88.5(2)  0(4)  Cu(l)  0(5)  74.8(1)  0(4)  Cu(l)  N(l)  89.8(2)  0(4)  Cu(l)  N(2)  91.0(2)  0(5)  Cu(l)  N(l)  92.5(2)  0(5)  Cu(l)  N(2)  88.8(2)  N(l)  Cu(l)  N(2)  178.7(2)  Cu(l)  0(1)  C(l)  120.3(3)  Cu(l)  0(2)  C(2)  108.8(3)  Cu(l)  0(2)  C(8)  131.5(3)  C(2)  0(2)  C(8)  119.6(4)  Cu(l)  0(4)  C(9)  121.6(3)  Cu(l)  0(5)  C(10)  109.5(3)  Cu(l)  0(5)  C(16)  129.9(3)  C(10)  0(5)  C(16)  120.6(4)  0(1)  C(l)  C(2)  121.6(4)  0(1)  C(l)  C(16)  121.7(5)  C(2)  C(l)  C(6)  116.8(4)  0(2)  C(2)  C(l)  113.5(4)  0(2)  C(2)  C(3)  124.7(4)  C(l)  C(2)  C(3)  121.8(5)  C(2)  C(3)  C(4)  119.9(5)  C(3)  C(4)  C(5)  120.3(5)  C(3)  C(4)  C(7)  120.7(6)  C(5)  C(4)  C(7)  119.0(5)  C(4)  C(5)  C(6)  120.0(5)  C(l)  C(6)  C(5)  121.2(5)  0(3)  C(7)  C(4)  124.2(6)  0(4)  C(9)  C(10)  120.1(4)  0(4)  C(9)  C(14)  122.1(4)  C(10)  C(9)  C(14)  117.7(4)  0(5)  C(10)  C(9)  113.6(4)  0(5)  C(10)  C(ll)  126.3(4)  C(9)  C(10)  C(ll)  120.1(5)  C(10)  C(ll)  C(12)  121.3(5)  C(ll)  C(12)  C(13)  118.8(5)  C(ll)  C(12)  C(15)  121.7(6)  C(13)  C(12)  C(15)  119.4(5)  C(12)  C(13)  CC(14)  120.7(5)  C(9)  C(14)  C(13)  121.2(5)  0(6)  C(15)  C(12)  126.7(7)  H y d r o g e n bonds (A) and C - H —O interactions  Table 4-2-5  B  A - H — B (• )  A  H  N(l)  H(2)  0(3)©  0.99  2.09  3.064(6)  169  N(l)  H(3)  O(l)©  0.99  2.13  3.085(8)  162  N(2)  H(5)  0(4)®  0.99  2.11  3.089(7)  171  N(2)  H(6)  0(6)©  0.99  2.40  3.341(8)  159  C(13)  H(15)  0(3)®  0.99  2.51  3.270(7)  133  C(16)  H(9)  0(3)®  0.99  2.52  3.127(6)  119  A-H  H  -B  A--B  Symmetry operation:, © x, y, 1+z; ® x-1, y, z; ® 1+x, y, z; ® x, y, z-1; ® -x, y-1/2, -z; ® 1+x, y, 1+z. '  89  Fig 4-2-6 T h e packing of Cu(II)-bis(vaniUinato)bis(aninionia) in a monoclinic cell. T h e h y d r o g e n b o n d s are indicated b y thin lines.  unit  <  Spectroscopic  FTIR  90  analysis  spectroscopy  T h e FTIR  spectra of the polycrystalline green solid a n d pure vanillin  c o m p a r e d in Fig. 4-2-7 and primary FTIR T a b l e 4 - 2 - 6 . T h e p e a k at 3 2 0 0 c m  -  1  was  vibrational assignments are present  in the spectrum o f pure vanillin  was  assigned as the O H stretching vibration. H o w e v e r , i n the s p e c t r u m o f complex,  n e w peaks appeared in the region of 3 2 0 0 - 3 4 0 0 c m  to N - H v i b r a t i o n . T h e p e a k w i t h a b r o a d s h o u l d e r at 7 3 0 c m "  -  1  in  the  , w h i c h were  1  due  in the spectrum  vanillin d u e to the phenolic O H out o f plane d e f o r m a t i o n w a s absent i n  the  s p e c t r u m o f the green solid. T h i s observation supported the conclusion that phenolic h y d r o x y l g r o u p was involved in the formation o f the copper  of  the  complex.  T h e s p e c t r u m o f the c o p p e r c o m p l e x also contains a n e w p e a k at 4 4 8 c m " .  This  w a s assigned to C u - N b o n d i n g ( H a t h a w a y a n d T o m l i n s o n , 1970). T h e p e a k  at  1  1150 cm" complex,  1  d u e to C - O - C b o n d i n g i n p u r e vanillin w a s shifted to 1120 c m consistent with the coordination of m e t h o x y l  1  in  oxygen.  T h e m a s s s p e c t r u m o f the g r e e n crystalline solid s h o w e d a p e a k at m / e w h i c h w a s assigned as a n (M-2NH3) + f r a g m e n t . F r o m  -  =  366  the m a s s spectrum  elemental analysis, the f o r m u l a o f the c o m p l e x c a n be expressed  and  as  [Cu(vanillin)2(NH )2]. 3  T h e electronic spectrum of a m u l l of the green solid (Fig. 4-2-8) s h o w s a b s o r p t i o n b a n d s at 5 9 0 n m ( 1 6 , 9 0 0 c m  -  1  ) and 770 nm.(13,000 cm" ), 1  w e r e a s s i g n e d as d - d e l e c t r o n transitions, as is t y p i c a l f o r the p r e s e n c e [CUO4N2] c h r o m o p h o r e s ( B u l l o c k et al.,  1974).  two w h i c h of  the  i  Fig 4-2-7  I R spectra o f vanillin a n d vanillin-copper c o m p l e x , a) V a r i i l l i n , b)  Vanillin-copper-ammonia  complex.  92  400  600  800  1000  Wavelength  Fig 4-2-8  U V - v i s i b l e spectrum o f a N u j o l m u l l o f the  1200  (nm)  vanillin-copper-complex.  1400  93  Table 4-2-6 Assignment of main absorption bands in IR spectra o f vanillin and copper-vanillin complex.  Copper-vanillin complex  Vanillin  cm-1  cm-1 3174  3050-3350  Assignment  O H stretching N H stretching  1654  1666  C = 0 stretching  1496  1509  Aromatic skittle vibration  1310  N H symmetric deformation  1120  1160  C - O - C antisym stretching  862  859  C H out plane deformation  730  O H out plane deformation  725, 652 449  N H rocking C u - N stretching  94  ESR  spectroscopy  At r o o m temperature, the polycrystalline p o w d e r e d sample o fthe green  solid  gives rise t oa nexchange n a r r o w e d anisotropic unresolved E S R spectrum  (Fig.  4 - 2 - 9 a ) , w h i c h d o e s n o t e x h i b i t h y p e r f i n e s p l i t t i n g , b u t p r o v i d e s g / / a n d g_|_, v a l u e s o f2 . 2 9 5 a n d 2 . 0 6 r e s p e c t i v e l y . T h e s p e c t r a o f p o l y c r y s t a l l i n e [Cu(vanillin)2(NH3)2] s h o w n oc h a n g e o v e r the t e m p e r a t u r e r a n g e 1 1 5 K t o 3 5 0 K , s u g g e s t i n g that t h e r e i s n of l u x i o n a l b e h a v i o r . X - r a y  crystallographic  s t u d y s h o w e d t h a t t h e c o o r d i n a t i o n a r o u n d t h e C u ( I I ) i o n i s a O2N2 s q u a r e with two o x y g e n donors f o r m i n g adistorted elongated octahedron; the  plane  elongation  a x i s i s a t 7 5 ° t o t h e O2N2 p l a n e . T h e o v e r a l l g e o m e t r y a r o u n d C u ( I I ) i o n i s s i m i l a r t othat i nCu(NH )2(CH C02)2 ( H a t h a w a y a n d T o m l i n s o n , 1 9 7 0 ) . 3  T h e  3  e l o n g a t i o n a x e s o f t h e t w o c r y s t a l l o g r a p h i c sites o fe l o n g a t e d  rhombic-octahedral  c o o r d i n a t i o n e n v i r o n m e n t o ft h e C u ( I I ) a r e n e a r l y a l i g n e d i nt h e c r y s t a l v e c t o r s a r e 8 °a p a r t ) . T h e a l i g n m e n t o ft h i s u n i q u e a x i s i nt h e  (the  coordination  s p h e r e o fc r y s t a l l o g r a p h i c a l l y r e l a t e d s i t e s m e a n s t h a t t h e o b s e r v e d g - v a l u e s i n the solid state c o r r e s p o n d t othe m o l e c u l a r axes ( H a t h w a y a n d Belling,  1970).  T h e s i g n i f i c a n c e o fthis r e s u l t i s t h a t t h e o b s e r v e d g - v a l u e s c a n b eu s e d t o i d e n t i f y t h i s t y p e o f b o n d i n g i n o t h e r s y s t e m s , e.g. C u ( I I ) f i x e d i n w o o d . T h e g v a l u e o f2 . 2 9 5 c o r r e s p o n d s t o t h e e l o n g a t e d O - C u - 0 a x i s a n d t h e m a g n i t u d e o f ( g / / - 2 ) / ( g j _ - 2 ) s u g g e s t s a g r o u n d s t a t e i n w h i c h t h e h o l e r e s i d e s i n t h e d 2_y2 x  orbital (Hathaway and T o m l i n s o n ,  1970).  T h e g r e e n c o m p l e x [Cu(vanillin)2(NH3)2] d i s s o l v e d s u f f i c i e n t l y i nD M S O  that  an E S R spectrum was observable. T h e E S R spectrum o fthe solution a t1 1 5 K i s s h o w n i nF i g . 4 - 2 - 9 b . A l t h o u g h t h e g / / a n d A / / f e a t u r e s a r e w e l l r e s o l v e d , t h e f e a t u r e s i nt h e p e r p e n d i c u l a r r e g i o n a r e l e s s r e s o l v e d . N o n e t h e l e s s , t h e  lineshape  i n that r e g i o n i s t y p i c a l o fa no r t h o r h o m b i c s y s t e m . T h e s p e c t r u m w a s  simulated  95  using the parameters given in T a b l e 4-2-7. T h e g-values agree well with from  those  t h e p u r e g r e e n p o w d e r . T h e A / / a n d g / / v a l u e s a r e t y p i c a l o f a CUO2N2O2  c h r o m o p h o r e (Peisach a n d B l u m b e r g , 1974; Pilbrow, 1990). A l l o f the  above  suggests that the c o m p l e x retains the structure [Cu(vanillin)2(NH3)2] in S u p p o r t for this w a s obtained DMSO  from  DMSO.  the electronic spectrum o f the c o m p l e x  w h i c h retained the features o f the m u l l  in  spectrum.  B a s e d o n t h e a b o v e a s s i g n m e n t t h a t t h e h o l e o c c u p i e s t h e d 2_y2 o r b i t a l , t h e n  the  , d 2 — > d 2_y2 i n  the  x  electronic s p e c t r u m c a n b e tentatively assigned as d ^ , d region 16.9 k K a n d the d  x  y  z  z  x  - > d 2_ 2 i n t h e r e g i o n 1 3 . 0 k K b y a n a l o g y x  3  with  y  C u ( N H ) 2 ( C H C 0 2 ) 2 (Hathaway and Tomlinson, 3  v  1970).  As s h o w n in table 4-2-7, the vanillin-copper c o m p l e x s h o w e d a m u c h  smaller  A// and a larger g// value than those of copper sulphate in a m m o n i u m  hydroxide  solution. This change in the spectral parameters o f the vanillin-copper  complex  is c o n s i s t e n t w i t h the r e p l a c e m e n t o f t w o o f the a m m o n i a l i g a n d s i n c o p p e r i o n s b y c o p p e r - o x y g e n b o n d i n g ( S e n e s i , et ah,  tetrammine  1989; Ruddick,  1992),  reflecting the s o m e w h a t m o r e ionic environment. W o o d treated with a n  aqueous  C u ( e n ) 2 S 0 4 solution has the largest A / / a n d smallest g//, indicating that  copper  c o m p l e x in the C u ( e n ) 2 S 0 2 treated w o o d has four equatorial  copper-nitrogen  d o n o r bonds (Farkas and Kurzak, 1990). E S R parameters of the vanillin-copper c o m p l e x is i n g o o d a g r e e m e n t w i t h that o f a m m o n i a c a l c o p p e r c a r b o n a t e w o o d (Ruddick, 1992), suggesting  the vanillin-copper c o m p l e x appears to  the s a m e configuration as c o p p e r i n the w o o d treated w i t h a m m o n i a c a l carbonate, in w h i c h two copper-oxygen and two copper-nitrogen bonds f o r m a plane.  treated have  copper  equatorial  96  Fig 4-2-9 in DMSO  E S R spectra o f vanillin-copper c o m p l e x a) solid at r o o m temperature, solution at 115 K .  b)  97  Table 4-2-7. T h e E S R parameters for vanillin-copper complex, solution a n d the copper treated w o o d at r o o m temperature.  // x 10- c m -  g//  A  4  C u S 0 i n N H O H 4  193  1  4  CuS0 inH 0 4  copper  g l  1  2.24  138  2.40  2.07  2  -  2.295  2.06  3  175  2.295  2.054  1  2  Vanillin-CopperA m m o n i a complex -insolid -inDMSO  (  g  x  x  gyy =  =  2.045, 2.063)  W o o d treated with C u C 0 / N H O H 3  4  4  [Cu(en) ]S0 2  4  in water  4  166  2.27  2.07  190  2.20  2.06  data f r o m Ajiboys a n d B r o w n ( 1 9 9 0 ) ; at r o o m temperature, at 115 K , DMSO = dimethyl sulfoxide, the parameters w e r e obtained b y a simulation o f the s p e c t r u m using the p r o g r a m C L P O W p r o v i d e d b y the Illinois E S R R e s e a r c h C e n t e r . * d a t a from R u d d i c k ( 1 9 9 2 ) . 1  2  3  98  Effect  of complex  formation  on wood  properties  A m m o n i a c a l copper solution readily formed awater insoluble  complex  w i t h vanillin, p r o v i d i n g s u p p o r t for the hypothesis that, d u r i n g fixation, a m m o n i a c a l c o p p e r preservatives react w i t h the guaiacyl units o n lignin to stable copper-nitrogen complexes.  f o r m  T h e formation of such complexes supports  finding of enhanced nitrogen content in a m m o n i a c a l copper treated  the  w o o d  o b s e r v e d b y R u d d i c k ( 1 9 7 9 ) . It m a y a l s o h e l p e x p l a i n t h e c h a n g e s w h i c h in the physical properties of the a m m o n i a c a l copper treated w o o d . T h e  occur water  insoluble c o p p e r c o m p l e x e s f o r m e d i n the treated w o o d w i l l b e e x p e c t e d to h i g h l y l e a c h r e s i s t a n t ( H u g h e s et al., 1 9 9 4 ; R u d d i c k , 1 9 9 2 ) , a n d m a y a l s o  be induce  water repellent properties in the w o o d (Jin and Preston, 1992). T h e formation cross-linked copper-lignin complexes in a m m o n i a c a l copper treated w o o d  of  m a y  also be responsible for the enhanced protection against photodegradation  ( H o n  and Chang,  during  1985), reported to o c c u r i n a m m o n i a c a l c o p p e r treated w o o d  a b o v e g r o u n d w e a t h e r i n g e x p o s u r e tests (Jin, A r c h e r a n d P r e s t o n ;  1991).  From the review o f the literature o n the formation o f c h a m m i n e c o m p o u n d s , it is c l e a r that after a m m o n i a e v a p o r a t i n g f r o m a c o p p e r  copper tetiaammine  carbonate solution, copper marnmine carbonate was precipitated (Tomlinson and H a t h a w a y , 1 9 6 8 ) . T h e e q u a t i o n is p r e s e n t  C u C 0  3  +4 N H  3  -> C u ( N H ) + 3  4  2  as  +C 0 " -> C u ( N H ) C 0 I +2 N B 2  3  3  2  3  3  T h e structure o f the m a m m i n e s h o w e d that two nitrogen atoms f r o m a m m o n i a m o l e c u l e s i n the d i a m m i n e carbonate c o m p l e x w e r e connected to central copper ion with other oxygen atoms f r o m the carbonate group.  T h e  geometry o f the d i a m m i n e w a s aplaner-square p y r a m i d ( T o m l i n s o n a n d  f  two the  99  H a t h a w a y , 1 9 6 8 ) , w h i c h is i n a g r e e m e n t w i t h the p r o p o s e d structure o f the  copper  complexes in a m m o n i a c a l copper treated w o o d f r o m E S R parameters (Ruddick, 1992b). A s indicated b y the a b o v e facts, the fixation o f c o p p e r a n d nitrogen includes the reaction o f c u p r i a m m o n i u m ions with Hgnin, f o r m i n g a c U a m m i n e complex.  100  4.3  Whether the enrichment of nitrogen in ammoniacal-copper preservative treated wood increases the decay potential  4.3.1  W o o d treated with a m m o n i u m hydroxide  solutions  T h e nitrogen contents in the samples for each treatment are listed in T a b l e 4-3-1. T h e nitrogen content increased with increasing a m m o n i a concentration in the treating solutions. N o t surprisingly the p H o f the leachate recovered  f r o m  blocks s h o w e d a n increase, although the magnitude o f the rise i n p H w a s small a n d the leachate remained slightly acid. T h e m e a n weight losses o f the w o o d  samples  treated w i t h a m m o n i u m h y d r o x i d e e x p o s e d to three different fungi w e r e  plotted  against the a m m o n i a concentration o f treating solutions (Fig. 4-3-1). Analysis variance (ANOVA)  of weight losses of blocks treated with different  concentration  o f a m m o n i u m h y d r o x i d e solutions s h o w e d that slight reduction i n w e i g h t loss s i g n i f i c a n t f o r T. versicolor  at the 0.05 level.  F o r G. trabeum  the A N O V A  that increases in weight losses with increasing a m m o n i a concentration  e x p o s e d t o P.  From  was  showed  were  significant at the 0.10 level. T h e w e i g h t losses w e r e s H g h t l y i n c r e a s e d N o losses were recorded for blocks treated with 5 % or 1 0 % a m m o n i a  of  mass  solutions  placenta.  the results it is c l e a r that the a m m o n i a t r e a t m e n t a f f e c t e d the  o f e a c h f u n g u s d i f f e r e n t l y . Postia placenta  w a s extremely sensitive to  a m m o n i a treatment. Since the blocks w e r e not leached, their p H w a s  the slightly  i n c r e a s e d b y t h e a m m o n i a t r e a t m e n t a s d e m o n s t r a t e d b y ar i s e i n t h e p H leachate f r o m selected blocks,  from  activity  of  4.99 i n the control samples to 6.31 for blocks  treated with 1 0 % a m m o n i u m hydroxide. This increase in the p H was considered b e t h e m o s t l i k e l y c a u s e o f i n h i b i t i o n o f t h e P. placenta  (Highley, 1973; Zabel  Morrell, 1992). T h e weight loss decreased immediately in the a m m o n i a  treated  to and  101  b l o c k s at the l o w e s t n i t r o g e n retention ( 0 . 4 1 0 % ) to a p p r o x i m a t e l y 1 5 % t h e r e a f t e r t o a l m o s t z e r o . T h i s s e n s i t i v i t y o f P . placenta  and  to a m m o n i u m h y d r o x i d e  t r e a t m e n t o f w o o d h a d b e e n n o t e d p r e v i o u s l y . R u d d i c k et al. ( 1 9 8 2 ) s t u d i e d effectiveness o f three preservatives for protecting B u r m e s e hardwoods.  the  T h e y  reported that soil blocks treated w i t h 5 % a m m o n i u m hydroxide, a n d leached fourteen days w i t h ten changes o f the water during that period w e r e not b y P. placenta.  N o e x p l a n a t i o n f o r t h i s s e n s i t i v i t y o f P . placenta  T h e w h i t e r o t f u n g u s , T. versicolor  was  was also affected b y the  decayed  offered. a m m o n i a  treatment i n that, at the l o w e s t a m m o n i a concentration, the w e i g h t loss  decreased  slightly f r o m about 3 5 % i n the control samples to 3 0 % . A s the a m m o n i a  content  increased to 5%, the w e i g h t loss w a s r e d u c e d to 2 5 % . T h i s suggested that o f T. versicolor  for  activity  w a s s o m e w h a t inhibited b y the change i n p H , but a p p e a r e d to  offset this i n h i b i t i o n as the a m m o n i a c o n t e n t is i n c r e a s e d , p r o b a b l y b y utilizing the a v a i l a b l e n i t r o g e n . T h i s s l i g h t r e d u c t i o n i n t h e a c t i v i t y o f T. versicolor a m m o n i u m h y d r o x i d e treated w o o d is c o n s i s t e n t w i t h o b s e r v a t i o n s p r e v i o u s l y b y R u d d i c k et al. ( 1 9 8 2 ) i n a t r o p i c a l h a r d w o o d . trabeum  in reported  Gloeophyllum  w a s affected b y the addition o f a m m o n i a to the w o o d . T h e w e i g h t losses  r e c o r d e d i n c r e a s e d slightly w i t h i n c r e a s i n g a m m o n i a content. T h i s r e s p o n s e is c o n s i s t e n t w i t h a p r e v i o u s s t u d y u t i l i z i n g a m m o n i a t r e a t e d h a r d w o o d s ( R u d d i c k et al,  1982), where weight losses were similar in a m m o n i a and water  treated  controls. T h e magnitude o f the weight losses w e r e m u c h greater than in the previous  study.  It s h o u l d b e n o t e d t h a t s i n c e t h e s a m p l e s w e r e n o t l e a c h e d b e f o r e  testing,  s o m e o f the r e s i d u a l a m m o n i u m - c h e m i c a l s m a y h a v e b e e n lost d u r i n g the test. A m b u r g e y a n d Johnson (1978) have studied the effect o f a m m o n i u m hydroxide thiamine and available micronutrients in pine sapwood during decay b y G .  o n  102  trabeum.  T h e y c o n c l u d e d that increasing d e c a y resistance m a y be d u e to  factors  w h i c h inhibit the germination o f basidiospores a n d not to tWarnine depletion C o n s i s t e n t w i t h t h i s s t u d y , G . trabeum  w a s able to g r o w o n w o o d treated  alone.  with  a m m o n i u m hydroxide.  Table 4-3-1 Nitrogen content in the treated w o o d a n d p H o f the leachate solutions Treatment  Control  N %  0.0505 (0.004)  p H  4.99  1 % N H a  0.4104 (0.002) 5.96  5% N H  3  a  0.5451  6.28  1 0 % N H  3  (0.08)  value  a  0.6277 (0.05) 6.31  Each value represents m e a n o f four replicates. N u m b e r s in parentheses represent standard deviation for the average nitrogen content. a  3  a  103  c  43  $ Q.  T3 O O  0> CU  o  -a E 0) 03  •a  o  co <u co co  O  o o  CO I  % sso| iqB.ieM  104  4.3.2  W o o d treated with a m m o n i a c a l copper  solution:  All three fungi g r e w well o n the water-treated control samples. T h e r e  was  s o m e o v e r g r o w t h o f t h e a m m o n i a c a l c o p p e r - t r e a t e d s a m p l e s b y b o t h T.  versicolor  a n d P. placenta.  replicates  T h e m e a n percent weight losses determined for the five  samples in each group, together with the nitrogen contents are presented i n Tables 2 to 4 a n d F i g . 4-3-2. T h e w e i g h t loss data for the a m m o m a c a l c o p p e r wafers w e r e subjected to aone w a y ANOVA  for each fungus. T h e  treated  statistical  analysis confirmed that increase in the m e a n weight losses o f wafers treated  with  a m m o n i a c a l copper solutions containing 1%, 5 % a n d 1 0 % a m m o n i u m hydroxide w e r e s i g n i f i c a n t a t t h e 0 . 0 5 l e v e l f o r P. placenta  a n d G. trabeum.  This  confirmed  that the weight losses o f wafers treated w i t h copper sulphate i n higher  a m m o n i a  concentrations were significantly greater than the corresponding data for  wafers  treated with solutions containing l o w a m m o n i a concentrations for these two N o m a s s loss was observed for any o f the a m m o n i a c a l copper treated e x p o s e d t o T.  fungi.  wafers  versicolor.  B a s e d u p o n t h e m a x i m u m w e i g h t l o s s e s a c h i e v e d , P. placenta readily tolerate the h i g h a m m o n i a content in the a m m o n i a c a l copper b l o c k s , w h i l e f u n g a l a c t i v i t y b y T. versicolor  a n d G. trabeum  was able  to  treated  was impaired. This  r e s u l t i s s o m e w h a t s u r p r i s i n g , g i v e n t h e s e n s i t i v i t y o f P . placenta  to  a m m o n i a  t r e a t e d w o o d . It is p o s s i b l e t h a t t h e a m m o n i a w a s m o s t l y c o m p l e x e d t o t h e  copper  w i t h arelatively s m a l l a m o u n t b e i n g c o m p l e x e d to the w o o d . T h e leaching o f the t r e a t e d w o o d w o u l d r e m o v e a n y f r e e a m m o n i u m salts. It h a s b e e n w e l l t h a t P. placenta  established  c a n detoxify copper treated w o o d b y the formation o f insoluble  c o p p e r o x a l a t e w h i c h h a s l i t t l e e f f e c t o n t h e f u n g a l g r o w t h ( S u t t e r et al., Murphy  and Levy, 1983). This release of oxalic acid could also react  1983;  with  105  a r n m o n i a p r e s e n t i n t h e w o o d , i n c l u d i n g t h a t c o m p l e x e d w i t h c o p p e r . It is  worth  noting that the color o f the w o o d c h a n g e d f r o m green to anatural b r o w n color, consistent w i t h areaction with the copper a m m o n i a c o m p l e x f o r m e d in the T h i s d i s t i n c t d i f f e r e n c e i n t h e b e h a v i o r o f P . placenta  to a m m o n i a a n d  wood.  ammoniacal  c o p p e r treated b l o c k s w o u l d s u g g e s t that the p r o d u c t i o n o f o x a l i c a c i d is  an  inducible reaction, w h i c h does not take place in the absence o f the copper. r e s e a r c h is n e e d e d to investigate this p h e n o m e n o n . A t the l o w e s t  Further  ammoniacal  copper treatment the weight loss o f the decayed blocks decreased  slightly  c o m p a r e d to the w a t e r control, b u t at h i g h e r a m m o n i a concentrations the  weight  losses increased. T h e weight losses for the blocks impregnated with copper in  1 0 %  a m m o n i u m h y d r o x i d e w e r e c o m p a r a b l e to the untreated w o o d . T h i s increase i n the fungal activity with increasing nitrogen content in the w o o d suggests that the o f t h e n i t r o g e n is u t i l i z i b l e b y P . p l a c e n t a . It r e m a i n s u n k n o w n w h e t h e r nitrogen being used arises f r o m the c o p p e r - a m m o n i a complexes or  form  the  from  a m m o n i a -  w o o d reaction products, s u c h as a m i d e s or imines. T h e w e i g h t losses f o r the a m m o n i a c a l c o p p e r treated w a f e r s at the a m m o n i a c o n c e n t r a t i o n e x p o s e d t o G. trabeum,  lowest  were very small. T h e reason for  this is that the c o p p e r c o n t e n t o f (0.6 - 0.8 k g / m ) is c l o s e to the t h r e s h o l d f o r this 3  fungus (0.42 k g / m ) reported b y R i c h a r d s o n (1991). N o n e t h e l e s s , as the  a m m o n i a  3  concentration o f the treating solution increases, the weight losses increase  to  almost 10%. This suggests that with increased a m m o n i a concentration in the t r e a t i n g s o l u t i o n , t h e a b i l i t y o f G. trabeum  to cause d e c a y w a s enhanced.  p r o b a b l e e x p l a n a t i o n f o r t h i s p h e n o m e n o n , i s t h a t G. trabeum  was able  m e t a b o l i z e the e x c e s s n i t r o g e n i n the w o o d . T h i s is c o n s i s t e n t w i t h  to  increased  decay f o u n d in a m m o n i a treated w o o d . A n alternative explanation m a y postulated, based u p o n the hypotheses that during treatment o f w o o d  O n e  be with  106  a m m o n i a c a l copper solutions, several copper c o m p l e x are formed, s o m e o f w h i c h c o n t a i n a m m o n i a . It h a s b e e n o b s e r v e d t h a t t h e d e p l e t i o n o f c o p p e r  preservative  f r o m a m m o n i a c a l copper treated w o o d can be reduced b y increasing the c o n t e n t o f t h e t r e a t i n g s o l u t i o n ( R u d d i c k , 1 9 9 2 b ) . It is n o t u n e x p e c t e d  a m m o n i a therefore,  that the efficacy o f the copper preservative will be influenced b y the nature o f the c o p p e r c o m p l e x e s p r e s e n t i n the w o o d . A s the a m m o n i a c o n t e n t is i n c r e a s e d , proportion of copper-ammonia complexes formed in wood, versus  precipitated  c o p p e r salts, w i l l b e increased. T h e increase i n the f o r m a t i o n o f less c o p p e r - a m m o n i a c o m p l e x e s m a y a l l o w t h e G. trabeum  the  soluble  to tolerate the c o p p e r to a  greater extent. A l t h o u g h T. versicolor  o v e r g r e w all test w o o d samples, n o w e i g h t losses  w e r e recorded for those containing a m m o m a c a l copper. T h e green color o f the w a f e r s w a s r e t a i n e d . T h u s w h i l e T. versicolor  was only partially affected  b y  a m m o n i a t r e a t m e n t o f w o o d , its l o w t o l e r a n c e t o c o p p e r p r e v e n t e d it f r o m u t i l i z i n g t h e e n h a n c e d n i t r o g e n . T h e d i s t i n c t l y d i f f e r e n t r e s p o n s e o f t h e w h i t e r o t f u n g u s T. versicolor  to a m m o n i a c a l c o p p e r treated w o o d , c o m p a r e d to that o f the b r o w n rot  f u n g i G. trabeum  a n d P. placenta,  both o f w h i c h appeared to s h o w  enhanced  decay with increasing nitrogen content, m a y be explained in part b y their different d e g r a d a t i v e c a p a c i t y f o r l i g n i n . It h a s b e e n p r o p o s e d i n t h e p r e v i o u s  chapter  4 . 2 . 3 . 2 t h a t t h e c o p p e r - a m m o n i a c o m p l e x e s a r e f o r m e d w i t h l i g n i n . It w o u l d therefore not be unexpected that white rot fungi w o u l d be affected b y c o m p l e x f o r m a t i o n to agreater extent than b r o w n rot fungi. Further are required to e x a m i n e this  phenomenon.  such investigations  107  Table 4-3-2 Copper and nitrogen contents and weight losses o f the treated wood samples exposed to P. placenta.  CuO kg/m  3  Control  Weight loss %  0.0423  60.14 (1.19)  0.06%CuO-l%NH  3  0.7146  0.2373  47.13 (7.18)  0.06%CuO-5%NH  3  0.7404  0.3298  50.98 (3.33)  0.7702  0.3401  59.90 (4.31)  0.06%CuO-10%NH 1  Nitrogen %  3  a  Standard deviation for the average weight loss given in parenthesis.  Table 4-3-3 Copper and nitrogen contents and weight losses o f the treated wood samples exposed to G. trabeum.  CuO kg/m Control  Nitrogen %  Weight loss %  0.0429  61.90 (4.5)  0.06%CuO-l%NH  3  0.7264  0.2460  2.52 (1.09)  0.06%CuO-5%NH  3  0.7594  0.3261  7.59 (4.0)  0.7842  0.3386  11.3 (4.51)  0.06%CuO-10%NH 1  3  3  a  Standard deviation for the average weight loss given in parenthesis.  Table 4-3-4 Copper and nitrogen contents and weight losses of the treated wood samples exposed to T. versicolor.  CuO kg/m Control  Nitrogen %  Weight loss %  0.0441  49.22 (2.47)  0.06%CuO-l%NH  3  0.6944  0.2234  2.18 (3.19)  0.06%CuO-5%NH  3  0.7516  0.3324  1.63 (2.81)  0.7838  0.3447  0.40(1.20)  0.06%CuO-10%NH a  3  3  Standard deviation for the average weight loss given in parenthesis.  a  108  IT)  (%) S S O | ILJBIBM  109  5.  CONCLUSIONS  m a y be  B a s e d u p o n all o f the observations i n this study, the following made.  1. T h e d a r k e n i n g o f D o u g l a s - f i r w o o d a f t e r t r e a t m e n t w i t h  conclusions  ammoniacal  copper solution results f r o m the formation o f a taxifolin-copper-ammonia complex. 2. L i g n i n a n d h e m i c e l l u l o s e p l a y a n i m p o r t a n t r o l e i n n i t r o g e n during the treatment of w o o d with a m m o n i a c a l copper based  fixation  preservatives.  3. T h e r e i s e v i d e n c e t o s u g g e s t t h a t a m m o n i a r e a c t s w i t h c a r b o n y l a n d carboxyl acid groups in wood, amide and imine compounds being formed. 4. V a n i l l i n , a l i g n i n m o d e l c o m p o u n d , r e a c t e d w i t h a m m o n i a c a l  copper  s o l u t i o n , f o r m i n g a stable, w a t e r - i n s o l u b l e , c o p p e r c o m p l e x . It w a s s u g g e s t e d  mat  ammoniacal copper ions can react with lignin and f o r m diammine copper lignin c o m p l e x in the  wood.  5. T h e c o m p l e x f o r m e d f r o m the r e a c t i o n o f v a n i l l i n w i t h  ammoniacal  c o p p e r solution w a s f o u n d to contain t w o a m m o n i a ligands a n d t w o  copper-  oxygen bonds in aplane with two copper-oxygen bonds f r o m the m e t h o x y l  group  f r o m vanillin in the axial direction. 6. O v e r t h e test p e r i o d u s e d a 5 % a m m o n i u m h y d r o x i d e s o l u t i o n c a n d e c a y b y P. placenta  t o a l m o s t z e r o . A l t h o u g h s l i g h t l y r e d u c e d , T.  reduce  versicolor  produced a2 2 % weight loss in w o o d treated with 1 0 % a m m o n i u m hydroxide solution. H o w e v e r , the a m m o n i u m hydroxide treated-wood w a s likely decayed G. trabeum  fungus.  7 . T r e a t m e n t o f w o o d w i t h a m m o n i a c a l c o p p e r s o l u t i o n s s h o w e d t h a t P. placenta  h a s t h e g r e a t e s t d e c a y c a p a c i t y d u e to its c o p p e r t o l e r a n c e , a n d b o t h G .  b y  110  trabeum  a n d T. versicolor  w e r e unable to cause significant weight losses i n  treated with a m m o n i a c a l copper containing 1 % a m m o n i a . A s the a m m o n i a i n c r e a s e d , t h e w e i g h t l o s s c a u s e d b y G. trabeum  increased.  wafers content  Ill  7.  RECOMMENDATIONS (1) I n this study the b l a c k color o f D o u g l a s - f i r w o o d after treatment  with  a m m o n i a c a l c o p p e r solution w a s identified as resulting f r o m the f o r m a t i o n o f a taxifolin-copper-ammonia complex. Further w o r k s h o u l d focus o n remedies to this discoloration. It w a s r e p o r t e d t h a t c h e m i c a l a n d p h y s i c a l m e a s u r e s w e r e t a k e n t o  r e m e d y  the b r o w n stain p r o b l e m o f western hemlock, white pine a n d Douglas-fir  ( H u l m e  a n d T h o m a s , 1 9 8 3 ; M i l l e r et al., 1 9 8 3 ) . T h e c a u s e o f t h e s t a i n i n w e s t e r n  hemlock  w a s identified to b e d u e to the oxidation a n d c o n d e n s a t i o n o f catechin, a p o l y p h e n o l i c e x t r a c t i v e i n w o o d , w h i c h h a s a s i m i l a r s t r u c t u r e to t a x i f o l i n . It  m a y  be possible to carry out similar experiments w i t h Douglas-fir. T h e proposed experiments w o u l d  be:  a. E x a m i n e w h e t h e r c h e m i c a l m o d i f i c a t i o n o f t a x i f o l i n c o u l d b e  achieved,  w h i c h c o u l d alter the structure a n d reduce the reactivity o f taxifolin w i t h ammoniacal copper  solution.  b. E v a l u a t e p h y s i c a l pretreatment, u s i n g s t e a m i n g at h i g h t e m p e r a t u r e  to  reduce the precursor content in w o o d .  (2) Vanillin w a s u s e d as al i g n i n m o d e l c o m p o u n d , to e x a m i n e the of w o o d with a m m o n i a c a l copper solution. T h e structure o f the c o m p l e x useful information o n the fixation m e c h a n i s m o f a m m o m a c a l copper  reaction provided  based  preservatives. In practice, ammoniacal copper preservative formulations  are  c o m p o s e d o f ac o p p e r salt a n d another active biocide s u c h as arsenate i n A C A , a n d quat i n A C Q . T h e i r fixation m e c h a n i s m s are expected to b e m o r e  complicated.  112  Further w o r k should study the fixation m e c h a n i s m s o f combinations a m m o m a c a l copper ions with other active  of  biocides.  (3) R u d d i c k ( 1 9 9 2 a ) r e p o r t e d that soil-leached C C A - t r e a t e d  rnini-stakes  w e r e a t t a c k e d b y f u n g i , c a u s i n g c o n s i d e r a b l e w e i g h t l o s s e s . It w a s e x p l a i n e d this depletion m a y b e l i n k e d to bacterial action o n the c h e m i c a l i n w o o d  exposed  to w a t e r l o g g e d soil conditions, causing a b r e a k d o w n o f the c o p p e r c o m p l e x e s m a k i n g t h e m soluble. T h e higher nitrogen content in the a m m o m a c a l  that  and  copper-  treated w o o d could provide an abundant nitrogen resource for such bacterial growth. Further w o r k should investigate whether the enhanced nitrogen content in the treated w o o d could promote decay in a m m o m a c a l copper solution w o o d , e x p o s e d to water-logged  treated  soil.  (4) It w a s s u g g e s t e d t h a t t r e a t m e n t w i t h a m m o n i a c a l c o p p e r c a u s e d t h e l o s s o f s o l u b l e p r o t e i n n i t r o g e n i n w o o d ( K i n g et ah,  preservatives  1974) w h i c h  affect fungal colonization o n the w o o d . T h e effect o f a m m o n i a c a l copper and a m m o n i u m hydroxide o n the content o f soluble protein nitrogen in should be  investigated.  m a y  solution w o o d  113  7.  L  I  T  E  R  A  T  U  R  E  A f t , H . ( 1 9 6 1 ) C h e r n i s t r y o f d i h y c h o q u e r c e t i n . I. A c e t a t e d e r i v a t i v e s . J . O r g a n i c Chern. 26:1958-1963. Aho, P . E . ,R J . Seidler, H J . Evans, a n d P . N . R a j u (1974) Distribution, enumeration, and identification of nitrogen-fixing bacteria associated with in living w h i t e fir trees. P h y t o p a t h o l o g y 64:1413-1420. Ajiboys, S J . and D . R . B r o w n . 1990. Electron spin resonance study o f copper (Il)-cellulose complexes. J. C h e r n . Soc. F a r a d a y Trans., 86(1):  decay  soluble 65-68.  Allison, F . P., R . M . M u r p h y a n d C . J. K l e i n (1963) Nitrogen requirements for the d e c o m p o s i t i o n o f various k i n d s o f finely g r o u n d w o o d s i n soil. S o i l Sci. 96:187190. A m b u r g e y , T . L .and B . R . Johnson (1978) Effect of a m m o n i u m hydroxide on tMamine and available micronutrients in ponderosa pine sapwood. Phytopathology 68:951-954. Audier, H.(1966) Etude des composes flavaniques par spectrometrie de mass. Bull. Soc. Chim. Fr. 9:2892-2899. A v r a m i d i e s , S., S. E l l i s a n d J. L i u (1993) T h e alleviation o f b r o w n stain i n h e m - f i r through manipulation of Idln-drying schedules. Forest Prod. J. 43(10):65-69. Baechler, R . H . (1949) Reports of preservatives committees. Proc. A m . Preserv. Assoc. 45:14-61. Bariska, M . , C . Skaar a n d R W . D a v i d s o n (1969) Studies o f the a m m o n i a system. W o o d Sci. 2(2):65-72.  W o o d  wood-anhydrous  Bariska, M . and R. Popper (1971) T h e behaviour of cotton cellulose and w o o d in a m m o n i a atmosphere. J. P o l y m . Sci. 36:199-212.  beech  Bariska, M . and R. Popper (1975) A m m o n i a sorption isotherms of w o o d cotton cellulose. W o o d Sci. Technol. 9:153-163.  and  Barton, G . M .and J.A.F. Gardner (1958) Determination of dihydroquercetin in Douglas-fir and western larch wood. Anal. Chern. 30(1):279-281.  114  Barton, G . M .and J.A.F. Gardner (1963) C o l o r precursors in Douglas-fir. Prod. J. 13(4):216-220.  Forest  Bellamy, L . (1958) T h e Infrared Spectra of C o m p l e x Molecules; J o h n W i l e y and Sons, N e w Y o r k . Benson, H . K . and D . F . M c C a r t h y(1925) Composition of oleoresin of Douglas-fir; Ind. E n g . C h e r n . 17(2): 193-194. B e s t , C W . a n d G . D . C o l e m a n ( 1 9 8 1 ) A W P A S t a n d a r d M - l l : A n e x a m p l e o f its use. Proc. A m e . W o o d Preserv. Assoc. 77:35-40. Bramhall, G . (1966) Permeability o f Douglas-fir heartwood f r o m various areas growth in B . C . B . C . L u m b e r m a n . 50(1):98-102. Brauns, F . E .(1952) T h e chemistry o f lignin A c a d e m i c Press Inc. N e w Y o r k andp230.  of  p56  B r a y , M . W . a n d T . M .A n d r e w s (1924) C h e m i c a l c h a n g e s o f g r o u n d w o o d d u r i n g decay. Ind. E n g . Chern., 16:139-39. B u l l o c k , J . L ,R . J . H o b s o n a n d D . C . P o v e y (1974) Substituted p h e n o l s as ligands. P a r t I V . S i x a n d f o u r - c o - o r d i n a t e c o p p e r (II) c o m p l e x e s w i t h m t r o g e n b a s e s . X - r a y crystal structure analysis of bis-(2-memoxy-4-mtrophenolato)bis(pyridine)copper (II). J . C h e r n . S o c . 19:2037-43. Campbell, W . G . (1952) T h e biological decomposition of w o o d in w o o d ( L . E . W i s e a n d E . C .J a h n , eds.). R e i n h o l d , N . Y . 1061-1116.  chemistry  C a n a d a Y e a r B o o k , (1994); C h a p t e r 2: Forests. Statistics C a n a d a , O t t a w a , p 5 0 p442. Clarke,M . R . and J.R. R a k (1974) N e w development of waterborne for forest products. Forest C h r o n . 50(3): 114.  and  preservatives  Cooper, P A . (1991b) Cation exchange adsorption of copper on wood. protection 1(1):9-14.  W o o d  Coughlin, P.K.., A . E .M a r t i n , J . C .D e w a n , E.I. W a t a n a b e , J . E .B u l k o w s k i , J . M . Jehn, a n d S.J. L i p p a r d(1984) Synthesis a n d structure o f the imidazolate-bridged dicopper(II) ion in two binucleating macrocycles. Inorg. Chern. 23:1004-1009.  115  C o w l i n g , E . B . a n d W . M e r r i l l ( 1 9 6 6 ) N i t r o g e n i n w o o d a n d its r o l e i n deterioration. C a n a d i a n Journal of B o t a n y 44:1533-1544. C o w l i n g , E . B . ( 1 9 7 0 ) N i t r o g e n i n forest trees a n d its r o l e i n w o o d Abstracts o f uppsala dissertation in Science. 164.  w o o d  deterioration.  Creagh, D . C . and W . J . M c A u l e y . (1992) International Tables for X - r a y Crystallography; V o l . C . K l u w e r A c a d e m i c Publishers, Boston, p 219-222. Dahlgren, S.E. (1975) Kinetics a n d m e c h a n i s m of fixation of w o o d species a n d preservatives, Part V . Effect o f w o o d species a n d preservative composition o n the leaching during storage. H o l z f o r s c h u n g 26(3):84-95. Delaporte, N . a n d J.-J.M a c h e i x (1972) D o s a g e oxydimetrique e n m i l i e u n o n aqueux composes phenoliques d'origine vegatale. A n a l . Chim. Acta. 59:279-284. Deity, W . E . ,B . O . H e s t o n a n d S . H . W e n d e r (1955) A m p h o t e r i c titration o f s o m e flavanoid c o m p o u n d s with cupric sulphate. J. A m e r . C h e m . Soc. 77:162-165. Dwivedi, B . K . and R . G .A r n o l d (1973) Chemistry of ttaamine degradation in food p r o d u c t s a n d m o d e l s y s t e m . Ar e v i e w . J. A g r i c . F o o d C h e m . 21:54-58. E a d i e . J . a n d E . M .W a l l a c e . ( 1 9 6 2 ) S o m e o b s e r v a t i o n s o n t h e f i x a t i o n o f c o p p e r a n d a r s e n i c mPinus sylvestris s a p w o o d . J . I n s t . W o o d S c i . 1 0 ( l l ) : 5 6 - 6 5 . Emeleus, H . J . a n d A . G .Sharpe (1973) M o d e r n aspects o f inorganic R o u t e d g e &K e g a n P a u l L t d , L o n d o n .  chemistry.  Farkas E . a n d B . K u r z a k . (1990) Potentiometric a n d spectroscopic studies o f binary and ternary copper(II) complexes of histidinehydroxamic acid. J. C o o r d . Chem. 22(2): 145-151. Findlay, D . M . a n d N . G . R i c h a r d s o n (1983) W o o d treatment composition. C a n Pat. 1,146,704. F i n d l a y , W . P . K . ( 1 9 3 4 ) S t u d i e s i n t h e p h y s i o l o g y o f w o o d - d e s t r o y i n g f u n g i . I. Effect o f nitrogen content o n the rate o f decay o f timber. A n n . B o t , L o n d o n , 48:108-117. Foster, D . O . ,D . F . Zinkel and A . H .C o n n e r (1980) Tall oil precursors of Douglasfir.T a p p i 63(12): 103-105.  116  F r i t z ,E . ( 1 9 4 7 ) D e v e l o p m e n t o f C h e m o n i t e a n d its service r e c o r d . P r o c . A m e r . W o o d Preserv. Assoc. 43:285-292. Gardner, J.A.F. a n d G . M .Barton (1960) T h e distribution o f dihydroquercetin i n Douglas-fir a n d western larch. Forest Prod. J. 10(3): 171-173. Gordon, A . (1940) Impregnating material for preserving wood. U . S . Pat. 2,194,827. Graham, H . M .a n d E . F .Kurth. (1949) Constituents o f extractives f r o m Douglasfir. I n d . E n g . C h e r n . 4 1 ( 2 ) : 4 0 9 - 4 1 4 Hackbarth, W . a n d W . Liese (1975) EinfluP v o n olzanatomischen Eigenschaften u n d T r a n k l o s u n g s - F a k t o r e n a n f d i e k e s s e l d m c k - T r a n k u n g v o n fichte. H o l z R o h Werkst. 33(12):451-455. Hancock, W . V .(1957)) T h e distribution o f dihydroquercetin a n d a l e u c o a n t h o c y a n i d i n i n a D o u g l a s - f i r tree. F o r . P r o d . J . 7 ( 1 0 ) : 3 3 5 - 3 5 8 . H a r b o r n e , J . B . ,T . J .M a b r y a n d H . M a r b y ( 1 9 7 5 ) T h e f l a v o n o i d s . A c a d e m i c P r e s s , N e w Y o r k . H a r t f o r d ,W . H .( 1 9 7 3 ) C h e m i c a l a n d p h y s i c a l properties o f w o o d preservatives a n d w o o d p r e s e r v a t i v e s y s t e m s . I n " W o o d D e t e r i o r a t i o n a n d Its P r e v e n t i o n b y Preservative Treatments". E d .b y D . D .Nicholas. Syracuse University Press, Syracuse, N . Y . H a r v e y , D . E .a n d T s u n e o , A . ( 1 9 7 4 ) D o u g l a s - f i r w o o d q u a l i t y s t u d i e s . P a r t II. E f f e c t o f a g e a n d s t i m u l a t e d g r o w t h o n fibril a n g l e a n d c h e m i c a l c o n s t i t u e n t s . W o o d Sci. Technol. 8:255-265 Hathaway, B . J .a n d D . E . Belling. (1970) T h e electronic properties a n d stereochemistry of mono-nuclear complexes o f the copper(II) ion. Coordin. Chern. Rev. 5:143-207. H a t h a w a y , B . J . a n d A . A . G . T o m l i n s o n ( 1 9 7 0 ) C o p p e r (II) a m m o n i a Coordin. Chern. Rev., 5:1-43.  complexes;  Heuser, E . (1946) T h e chemistry o f cellulose; J o h n W i l e y & Sons Inc, N e w  York  Highley, T . L .(1973) Source o f increased decay resistance i n sodium hydroxideand ammonia-treated wood. Phytopathology 63(1):57-61.  117  Hillis,W . E . (1962) " W o o d Extractives" A c a d e m i c Press; N e w  Y o r k .  Hinojosa, O ; J. C . A r t h u r Jr. a n d T . M a r e s (1974) E l e c t r o n spin resonance studies of interactions o f a m m o n i a , copper, a n d c u p r i a m m o n i a with cellulose; J. A p p l i e d Polym. Sci. 18:2509-2616. H o b s o n , R . J . ,M . F . C . L a d d a n d D . C . P o v e y . 1973. Substituted p h e n o l as (III): C r y s t a l a n d m o l e c u l a r s t r u c t u r e o f b i s ( 4 - f o r m y l - 2 - m e t h o x y l phenolato)bis(pyridine)copper(II). J. Cryst. M o l . Struct. 3:377-388.  ligands  Hon, D . N - S and S-T. Chang. 1985. Photoprotection of w o o d surfaces b y ion complexes. W o o d and Fiber Science 2:92-100.  w o o d -  Hughes, A.S., R.J.M u r p h y , J.F. Gibson, and J.A. Cornfield. (1992) Examination o f p r e s e r v a t i v e t r e a t e d pinus sylvestris u s i n g e l e c t r o n p a r a m a g n e t i c r e s o n a n c e . Internal. Res. G r o u p o n W o o d Pres., D o c u m e n t N o : I R G / W P / 3 7 1 0 . Hughes, A.S., R J . M u r p h y , J.F. Gibson, and J.A. Cornified. (1994) Electron paramagnetic resonance ( E S R ) spectroscopic analysis of copper based p r e s e r v a t i v e s i n Pinus sylvestris. H o l z f o r s c h u n g 4 8 : 9 1 - 9 8 . H u l m e , M . A . (1979) A m m o n i a c a l w o o d preservatives. R e c o r d o f the 1979 Conven. o f the British W o o d Preserv. Assoc. L o n d o n . 38-50.  A n n .  H u l m e , M . A . a n d J.F. T o m a s (1983) C o n t r o l o f b r o w n stain in eastern white with reducing agents. Forest Prod. J. 33(9): 17-20.  pine  Hunt, G . M .and G . E .Garratt (1967) W o o d Preservation. McGraw-Hill, L o n d o n , N e w Y o r k . Ibers J . A . a n d W . C . H a m i t o n (1974) International Tables for X - r a y Crystallography, V o l . I V ; T h e K y n o c h press, B i r m i n g h a m , U . K . p 99-102 149.  and  Isenberg, I.H. (1980) P u l p w o o d s o f the U n i t e d States a n d C a n a d a . V o l . IConifers. 3 r d . E d i t i o n . Inst. P a p e r c h e m . , A p p l e t o n , W i s . 219. Jin, L . ,K . J .A r c h e r a n d A l a n F . Preston. (1991) Surface characteristics o f w o o d treated w i t h v a r i o u s A A C ,A C Q a n d C C A f o r m u l a t i o n s after w e a t h e r i n g . Int. R e s . G r o u p o n W o o d Pres. Doc. N o . I R G / W P / 2 3 6 9 . Jin, La n d A l a n F . Preston (1992) C o m m e r c i a l development o f A C Q in the U n i t e d States. C a n a d i a n W o o d Preservation Association, Proceeding, 13:43-54.  118  Jurd, L . (1962) "The chernistry of flavonoid compounds", E d . T . A . Geissman, M a c M i l l a n Co., N e w York, N . Y . Kaplunova, T.S., Z . K . Saipov and K h . A . A b d u a z i m o v ; (1986) T h e reaction mtroligriin with ammonia. Chemistry of natural compounds. 211:786-788.  T h e of  Kawase, K . (1962) Chemical components of w o o d decayed under natural conditions a n d their properties. J. Fac. A g r . H o k k a i d o U n i v . 52:186-245. K e n n e d y , R . W . (1955) Fungicidal toxicity of certain extraneous components Douglas-fir heartwood. M.F.Thesis, Faculty of Forestry, U B C . King, B., T . A . O x l e y and K . D . L o n g (1974) Soluble nitrogen in w o o d and redistribution o n drying. M a t . u. Organi. 9:242-254.  of its  Koval'chuk, B . V . and Y u . N . Forostyan (1972) Transformation of hydrolysis lignin f r o m sunflower husks in aqueous ammonia. Chemistry of Natural C o m p o u n d s , p 369-371. K r e b e r , B . ( 1 9 9 4 ) A d v a n c e s i n the u n d e r s t a n d i n g o f h e m l o c k b r o w n stain. M a t . u. Orga. 28:17-37. K u o , M , J . F . M c C l e l l a n d , S. L u o , P , C h i e n , R . D . W a l k e r , a n d C . H s e ; ( 1 9 8 8 ) Infrared photoacoustic spectroscopy of wood. W o o d and Fiber Science 20(1) 132145. K u p c h i n o v , B.J., V . A . Belyi and A . P . N e s h i k (1975) Selective transfer o f metal complexes. Izbirateryi Perenos Trenii 50-54.  w o o d -  Larsen M J . ,M . F . Jurgensen and A . E .H a r v e y (1978) N fixation associated with w o o d decayed b y s o m e c o m m o n fungi in western M o n t a n a . C a n . J. o f Forest Res. 8:341-345. 2  Lewis, H . F . (1950) Significant chemical components of western hemlock, Douglas-fir, western red cedar, loblolly pine and black spruce. T a p p i 33(6):299301. Liese, W . a n d J.Bauch. (1967) O n anatomical causes o f the refractory behaviour spruce a n d Douglas-fir. J. Inst. W o o d Sci., 191 4(1):3-13. M a b r y , T . J . ,K . R . M a r k h a m a n d M . B . T h o m a s (1970) T h e systematic identification o f flavonoids, Springer-Verlag N e w Y o r k Inc.  of  119  M a h d a l i k , M . ;J . R a c a n . ; M . M l c o u s e k a n d O . L a b s k y ( 1 9 7 1 ) C h a n g e s o f s o m e physical, mechanical, a n d chemical properties o f w o o d treated with liquid ammonia. J. P o l y m . Sci.,Part C 36:251-263. Mazzi, F . (1955) T h e crystal structure o f cupric tetrammine sulfate monohydrate C u ( N H ) S 0 • H 0 . A c t a Cryst. 8:137-141. 3  4  4  2  Mbafor, J . T .a n d Z . T .F o m u m (1989) Isolation a n d characterization o f taxifolin 6C - g l u c o s i d e f r o m Garcinia epunctara. J . N a t . P r o d . 5 2 ( 2 ) : 4 1 7 - 4 1 9 . M e r r i l l ,W . a n d E . B . C o w l i n g ( 1 9 6 6 ) R o l e o f n i t r o g e n i n w o o d d e t e r i o r a t i o n . I V . R e l a t i o n s h i p o f n a t u r a l v a r i a t i o n i n n i t r o g e n c o n t e n t o f w o o d to its susceptibility to decay. Phytopathology 56:1324-1325. M i l l e r , D . J . , D . M .K n u t s o n a n d R . D . T o c h e r ( 1 9 8 3 ) C h e m i c a l b r o w n s t a i n i n g Douglas-fir sapwood. Forest Prod. J. 33(4):44-48. Morgan, J. (1989) T h e evaluation a n d commercialization o f a n e w preservative. Proc. A m e r i . W o o d P r e s e r v . Associ. 82:16-25.  o f  w o o d  Morrell, J J . (1989) C o p p e r tolerant fungi: a brief review o n their effects a n d distribution. Proc. A m e r . W o o d Preserv. Assoc. F - 4 C o m m i t t e e Report A p p e n d i x B:8-12. M u r p h y , R J . a n d J . F .L e v y (1983^) P r o d u c t i o n o f c o p p e r o x a l a t e b y s o m e tolerant fungi. Transactions British M y c o l o g i c a l Society 81(1): 165-168. N i c h o l a s , D . D . ( 1 9 7 3 ) W o o d deterioration a n d its p r e v e n t i n g b y treatment, Syracuse University Press p l 5 .  copper  preservative  O s t m e y e r , J . G . ;T J . E l d e r a n d J . E . W i n a n d y ( 1 9 8 9 ) S p e c t r o s c o p i c a n a l y s i s o f s o u t h e r n p i n e t r e a t e d w i t h c h r o m a t e d c o p p e r a r s e n a t e . II. D i f f u s e r e f l e c t a n c e fourier transform infrared spectroscopy ( D R I F T ) .J. W o o d Chern. Technol. 9(1) 105-122. Paszner, L . (1994) W o o d chemical analysis laboratory for W o o d  473.  P e i s a c h , J . a n d W . E . B l u m b e r g ( 1 9 7 4 ) S t r u c t u r a l i m p l i c a t i o n s d e r i v e d from t h e analysis o f electron paramagnetic resonance spectra o f natural a n d artificial copper proteins. A r c h B i o c h e m . Biophy. 165:691-708. P e w , J . C .( 1 9 4 8 ) A f l a v a n o n e 70(9):3031-3034  from  Douglas-fir heartwood. J. A m e r . C h e m . Soc.  120  Pilbrow, J.R. (1990) Transition ion electron paramagnetic resonance. Press. P20.  O x f o r d  Plackett, D . V . , E . W . A i n s c o u g h a n d A . M .B r o d i e (1987) T h e examination o f p r e s e r v a t i v e - t r e a t e d r a d i a t a p i n e u s i n g e l e c t r o n s p i n r e s o n a n c e s p e c t r o s c o p y . Int. Res. G r o u p o n W o o d Preserv., D o c u N o . I R G / W P / 3 4 2 3 . Porter, L . J .a n d K . R . M a r k h a m . (1972) A l u m i n u m c o m p l e x e s o f flavanones dihydroflavonols. Phytochemistry 11:1477-1478.  and  Preston, A . F .a n d L . Jin (1991) W o o d - c h e m i c a l interactions a n d their effect o n preservative performance. In "The chemistry of W o o d Preservation". E d i . b y R. T h o m p s o n . T h e R o y a l Society of Chemistry. U . K . p 88-100. Rak, J. (1977) S o m e factors affecting the treatability o f spruce r o u n d w o o d a m m o n i a c a l preservative solution. H o l z f o r u . Holzverwert 29(3):53-56.  with  R e e v e s , R . ( 1 9 4 9 ) C u p r a m m o m u m - g l y c o s i d e c o m p l e x e s . II. T h e a n g l e b e t w e e n hydroxyl groups o n adjacent carbon atoms. J. A m e r . C h e m . Soc. 71:212-214. Richardson, N . G . (1991) A m m o m a c a l copper/quaternary a m m o n i u m c o m p o u n d w o o d preservative system. Proc. C a n . W o o d Preserv. Assoc. 12:38-53. R o g e r s , I . H . a n d J . F . M a n v i l l e ( 1 9 7 2 ) J u v e n i l e h o r m o n e n i i m i c s i n c o n i f e r s . I. Isolation o f (-)-cis-4-[r(R)-5'-dimethyl-3-oxohexane-l-carboxylic acid f r o m Douglas-fir wood. C a n . J. C h e m . 50(ll):2380-2382. R u d d i c k , J . N . R . ( 1 9 7 9 ) T h e n i t r o g e n c o n t e n t o f A C A - t r e a t e dw o o d . M a t . u. O r g a . 14:301-312. Ruddick, J.N.R. (1980a) " W o o d preservation in C a n a d a " Proc. A m e r . Preserv. Assoc. 76:191-204.  W o o d  Ruddick, J.N.R. (1980b) Treatability of lodgepole pine lumber with A C A and CCA. Forest Prod. J. 30(2):28-32. R u d d i c k , J . N . R . , R . S . S m i t h a n d T . B y r n e (1982) L a b o r a t o r y d e c a y test o f B u r m e s s In a n d K a n y i n treated w i t h three w o o d preservatives. Internat. Res. G r . W o o d Preserv. D o c N o . I R G / W P / 3 2 1 0 . 9PP. R u d d i c k , J . N . R . ( 1 9 8 9 ) H e a r t w o o d t r e a t a b i l i t y ; I n " S e c o n d g r o w t h D o u g l a s - f i r : Its management and conversation for value"; Forintek C a n a d a Corp. Special Publication N o , SP-32:78-79.  121  Ruddick, J.N.R. (1992a) Bacterial depletion of copper f r o m C C A - t r e a t e d wood. Mat. u. Organi. 27(2): 125-146. Ruddick, J.N.R.(1992b) T h e fixation chemistry of copper based preservatives. Proc. C a n . woodPreserv. Assoc. 13:116-137.  w o o d  Ruddick, J.N.R., K . Y a m a m o t o , K . Baxter and F . G .Herring (1994) Electron spin resonance studies o n amine-copper(II) w o o d preservatives. J. W o o d C h e m . a n d Techol. (In press) Sakamoto M . and T a k a m u r a K . (1978) Consecutive determination of rutin and quercetinby spectrophotometric measurements. M i c r o c h e m . J. 23:374-383. Schorger, A . W . (1917) T h e oleresin o n Douglas-fir. J. A m e r . C h e m . 39:1040-1044.  S o c ,  Schuerch, C . (1964) Principles a n d Potential.... W o o d plasticization. Forest P r o d . J. 14(9):377-381. Senesi, N . , G . Sposito and G . R . Bradford. (1989) Iron, copper, a n d c o m p l e x a t i o n b y forest l e a f litter. F o r . Sci., 3 5 ( 4 ) : 1 0 4 0 - 1 0 5 7 .  manganese  Smith, W . H . (1970) Tree pathology: Ashort introduction. A c a d e m i c press, York. P. 150-174.  N e w  S o l a r R . a n d I. M e l c e r ( 1 9 7 8 ) P h y s i c o c h e m i c a l a n d c h e m i c a l c h a n g e s o f h o r n b e a m w o o d lignin in the process o f w o o d plasticization with a m m o n i a water solution. Cellulose chemistry and technology 12:615-619. Stephens, R . W . , G . E . B r u d e r m a n n , P.I. M o r r i s , M . S . H o l l i c k a n d J . D . C h a l m e r s ( 1 9 9 4 ) V a l u e a s s e s s m e n t o f t h e Canadian p r e s s u r e t r e a t e d w o o d i n d u s t r y . C a n a d i a n Forest Service Department of Natural Resources Canada. N o . 4Y002-0187/01-SQ. Sudman, C - E .(1984) Tests with ammoniacal copper and alkyl a m m o n i u m c o m p o u n d s as w o o d preservatives. I R G / W P / 3 2 9 9 . Sutter, H . P . E . B . G . Jones a n d O . W a l c h l i (1983) T h e m e c h a n i s m o f copper t o l e r a n c e i n Poriaplacenta ( F r . ) C k e . a n d Porta vailanti ( p e r s . ) F r . M a t e r i a l u . Organismen 18(4):241-262. Szymanski, H . A . (1964) I R theory and practice of infrared spectroscopy. press.  P l e n u m  122  Takamura K a n d M . S a k a m o t o (1978) Spectrophotometric studies o f flavanoidcopper(II) complexes in methanol solutions. Chern. a n d P h a r m . Bull. 26(8):22912297. Tardif, J . W . (1959) Problems in improving the brightness o f groundwood. A p p i t a 13:58-73.  eucalypt  Tomlinson, A.A.G. and B . J. H a t h a w a y (1968) T h e electronic properties and stereochemistry o f the copper(II) ion. Part I V . S o m e o U a m m i n e complexes. J. Chern. Soc. (A):2578-2583. T r o u g h t o n , G . E . a n d S. C h o w (1973) H e a t - i n d u c e d color-intensity c h a n g e coastal Douglas-fir a n d white spruce. W o o d a n d Fiber 4(4) 259-263. T h e M e r c k index (1983) 150.  in  10th Edition. M e r c k & C O . ,Inc. R a h w a y . N . J . U.S.A.  W a n g , P . Y . , H.I. B o l k e r , a n d C . B . P u r v e s (1967) U r o n i c acid ester groups i n softwoods a n d h a r d w o o d s . T a p p i 50(3): 123-124.  p  some  W e a v e r , F . W . a n d M . P . L e v i (1979) T h e treatability o f southern pine a n d Douglasfirh e a r t w o o d w i t h creosote, m o d i f i e d creosote^ c h r o m a t e d copper arsenate, a n d a m m o n i a c a l copper arsenate. Proc. A m e r . W o o d Preserv. Assoc. 75:176-187. Wilkinson, J. G . (1979) "Industrial T i m b e r preservation: T h e Importance T i m b e r Preservation" Associated Business Press, L o n d o n , p 3-24.  of  W i n a n d y , J . E . ;R . S . B o o n e , L . R . G j o v i k a n d P . L . P l a n t i n g a ( 1 9 8 9 ) A C A a n d C C A preservative treatment a n d r e d r y i n g effects o n b e n d i n g properties o f Douglas-fir. Proc. A m e r . W o o d Preserv. Assoc. 82:107-118. Zabel, R . A . and J.J.M o r r e l l(1992) W o o d Microbiology. A c a d e m i c Press N e w Y o r k . Z h b a n k o v , R . G . ( 1 9 6 6 ) T h e i n f r a r e d s p e c t r a o f c e l l u l o s e a n d its d e r i v a t i v e . Consultants Bureau, N e w Y o r k .  Inc.  

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