Figure 1. — Chromatogram of cellulose pyrolyzed at 300° C. (Lipska and Wodley 1968). 

 The peaks are (1) fixed gases; (2) aoetaldehyde ; (4) furan; (5) propionaldehyde; 

 (6) acetone; (9) 2 } 3-butanedione; (10) water; (13) acetol; (14) methyl formate +; 

 (16) furfural +; (19) propionic acid; (20) formic acid; (23) acetic acid; (24) 

 furfuryl alcohol; (25) butyrolactone ; (28) cyclohexanone; and (29) tigaldehyde . 



ISOLATION OF THE CHEMICAL COMPONENTS OF 

 WESTERN COTTONWOOD 



Western Cottonwood (Populus trichocarpa) was selected for this study for several 

 reasons. It is currently considered a low-grade western hardwood of little utility but 

 may have future commercial value. The chemical investigations have been limited to 

 certain commercial and biological aspects (Mehring and Schramm 1949; Butin 1960; 

 Mojeika and Sergeera 1957). There has been some reported work dealing with the plenyl 

 glucosides found in the bark (Loeschcke and Franchsen 1964; Pearl and Larson 1965) and 

 some information has also been available on the polysaccharides of the related species, 

 Populus tremuloides and Populus grandidentata (Jones, Purves, and Timell 1961; Thompson 

 and Wise 1952). This work will greatly increase our knowledge about this potential raw 

 material. Selection of western cottonwood simplifies the investigation procedures be- 

 cause hemicelluloses found in the plant consist mainly of xylan. Another advantage in 

 using this wood is the low content of extraneous materials, especially ash. This helps 

 insure isolation of the carbohydrates in a nearly pure form. 



The chemical analysis and isolation of the polysaccharide component of cottonwood 

 were carried out mainly by McGinnis 5 and are reported elsewhere in more detail 

 (Shafizadeh and McGinnis 1971). Further analysis of the inorganic materials was carried 

 out by this author. 



A heartwood sample of the cottonwood was analyzed to provide the cell wall 

 polysaccharides and the other components shown in the following tabulation. Hydrolysis 



5 McGinnis, op. cit. 



4 



