ETHYL ALCOHOL FROM WOOD WASTE. 



59 



The reason for these marked differences between the evergreens 

 and the deciduous trees must reside in their chemical composition 

 rather than in any physical or structural differences and, no doubt, 

 may be ascribed primarily to differences in cellulose content. As a 

 class, the deciduous trees contain less cellulose and more lignin and 

 wood gums than the coniferous species. The gums, such as xylan 

 and araban, are in part converted into the respective pentose sugars. 

 This accounts for the comparatively high total sugar yields and also 

 for the comparatively small portion of the sugar that is fermentable. 

 Those constituents, lignin and gums, which make the hardwoods as a 

 class, and especially beech, birch, and maple, desirable in destructive 

 distillation, bring about a different result in alcohol production, and 

 it is questionable whether commercial recovery would be possible 

 from any of those species alone that are mentioned in the above table. 

 If mixed in small amounts with coniferous waste, the broad-leaved 

 species will not interfere with the production of sugar and alcohol 

 from the coniferous waste, in spite of the large amounts of acetic and 

 formic acids produced. In fact, it is when the recovery of these acids 

 .is considered in conjunction with the alcohol process that hardwood 

 waste utilization appears possible if the waste is available in sufficient 

 quantity. 



Ordinary destructive distillation practice recovers 180 pounds of 

 crude acetate of lime per cord of wood. Under good conditions this 

 may be brought up to 200 or 220 pounds per cord. 



The following table shows the amounts of acetic and formic acid 

 produced from beech, birch, and maple, the three species commonly 

 distilled : 



Cook No. 



Species. 



Acetic acid 

 (per cent 

 of original 

 dry wood). 



Formic 



acid (per 



cent of 



original 



dry wood). 



Total vola- 

 tile acid ' 

 (per cent 

 of original 



dry wood). 



7G 





4.800 

 4.700 

 3.770 



0.445 

 .706 

 .512 



5.245 



62 



Birch 



5 406 



73 





4.282 









The amounts of acetic acid produced, as shown in the above table, 

 are equal to or greater than the amounts produced by the destructive- 

 distillation process; and, aside from the technical value of the facts 

 disclosed, additional light is thrown on the difference in chemical 

 composition of those woods and woods of the coniferous species. 



SOURCE OF FERMENTABLE SUGAR. 



As previously outlined, the source of the fermentable sugar ob- 

 tained from the hydrolysis of wood has long been a mooted question. 

 Cellulose and materials higher in cellulose than wood, however, have 



