ETHYL ALCOHOL FROM WOOD WASTE. 43 



In cook No. 30, with an original ratio of water to wood equal to 

 1 to 1, the ratio increased to 1.62 to 1, an increase of 62 per cent. In 

 cook No. 34, with an original ratio of 1.25 to 1, the ratio increased to 

 1.86 to 1, an increased of 61 per cent, which was practically identical 

 with that of cook No. 30. In both cooks the yields of total sugars, 

 percentages of total sugars fermentable, and yields of alcohol were 

 practically identical, as shown in the table of results on series IV, 

 page 36. It seems, therefore, that if there is sufficient water to 

 insure a good mixture of the catalytic agent with the wood, both the 

 water and acidity of the solution added are without effect; and that, 

 of these two variables, the only one affecting the yields is the con- 

 centration of the catalytic agent based on the amount of dry wood 

 present. 



Increasing the concentration of the catalytic agent caused increased 

 yields of total sugars up to about 1.5 per cent of sulphuric acid; then 

 the yields begin to decrease, although the portion of the sugars that 

 is fermentable increased without a break in the curve. The increase 

 in the amount of sugars fermentable is sufficient to offset the decrease 

 in total sugars, and consequently the resulting alcohol yield is prac- 

 tically constant. The explanation of this condition, as shown on 

 pages 30 to 33, is that the nonfermentable sugars (the pentoses) are 

 the more unstable under the conditions used, and pentose decompo- 

 sition takes place with increasing amounts of the catalytic agent. 

 This pentose decomposition accounts for a decrease of the total 

 sugar yield and an increase of the fermentable sugars, especially if 

 there is little or no hexose decomposition; and the result is a practi- 

 cally constant alcohol yield similar to that obtained. As in the 

 inversion of cane sugar in the presence of an acid, here also the speed 

 of the reaction is probably determined by a combination of the 

 catalytic effects of both the hydrogen ions and the non-ionized acid; 

 moreover, the increased amounts of sugar formed with increased 

 acid concentration may in part be a result of the non-ionized molecule. 

 However, this is not the full explanation of the conditions observed. 

 If it were, the 4 per cent acid series should give yields as much 

 greater than those of the 2.5 per cent acid as the 2.5 per cent acid 

 yields are greater than those of the 1 per cent; but this is not the 

 case. 



The above discussion has been limited entirely to the results of the 

 experiments on spruce. Only two cooks were made on shortleaf 

 pine, and these were insufficient to warrant any conclusions, especially 

 in view of the complex nature of the raw material. 



