Table 1 .--Comparison of ehav from cottonwood and its components 



Component : 



Composition 

 percent 





Char formed 



(percent) 







: Neat 



: ZnCl 2 







NaOH 





\ A 1 ! B 2 



: A j B 





A 



B 





Cel lulose 



44 



6 2.6 



33 14 



.5 



22 



9 



7 



Xylan 



21 



6 1.3 



27 5 



.7 



31 



6 



5 



Milled wood lignin 



32 



45 14.4 



45 14 



.4 



45 



14 



A 



Sum of char from components 18.3 34.6 30.6 



Actual organic char from wood 19.0 35 . 30 . 



Difference -.7 -.4 .6 



Error (percent) 3.7 1.1 3.2 



1 



Residue at 450° C. from TGA minus treatment in percent. 

 2 Net char at 450° C. X percent the component makes up of whole wood. 



The effects of 5 percent NaOH on the pyrolysis of cottonwood can be seen on DTA as 

 being generally made up of the combined effect of alkali on cellulose and xylan. The 

 net process was exothermic after water loss (fig. 16). A slight dip occurred in the 

 DTA trace at about 240° C. and corresponds to the endotherm at that temperature on the 

 DTA of cellulose treated with alkali (fig. 6). The TGA shows a char which was equal 

 to the weighted chars from the alkali treated components (table 7) . 



The volatile products from the pyrolysis of wood were qualified and quantified 

 using previously described methods. Milled wood lignin was studied by pyrolysis gas 

 chromatography so that any major peaks from this component could be identified on the 

 chromatogram of wood . 



The pyrolysis of milled wood lignin gave four major peaks on the chromatogram (fig. 

 17). In addition to fixed gases, these peaks appeared to be methanol (L^), acetic acid 

 (L 2 ) , and the largest peak, (L3) , which is unidentified. Kitao and Watanabe (1967) 

 identified several products from the pyrolysis of beech milled wood lignin. Three 

 major peaks, presumably of low molecular weight, were not identified in the paper, but 

 they could certainly be methanol, ethanal, and acetic acid. The products they did 

 identify formed relatively minor peaks except for a combined peak of tranisoeugenol and 

 pyrogallol-1 , 3-dimethylether . Possibly this is the major peak labeled L3 on the 

 chromatograms , but, due to differences in columns and wood species, little can be said 

 concerning the identity of the peak. It should be noted that the same peak, (L3), 

 appears in all the chromatograms of wood and is greatly reduced by ZnCl2 treatment 

 (figs. 17 and 18). The possibility of using this pyrolysis procedure to quantify lignin 

 content should be investigated to see if this time-consuming procedure could be automated. 



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