ETHYL, ALCOHOL FROM WOOD WASTE. 



41 



fermentable sugars increases. As a result the total yield is not 

 appreciably lessened and the alcohol yield remains practically con- 

 stant. 



In this series is seen again the importance of complete data; that 

 is, data on total sugars, percentage of total sugars fermentable, and 

 alcohol yields. All of these are necessary for a proper interpretation 

 of the results, especially in an experiment like this, in which there is 

 an apparent neutralization of two factors that vary in different ways. 



A study of these two variables — namely, the ratio of water to wood 

 and of acid to wood — shows that they are not mutually dependent, 



SHORTLEAF 



iS^FtUCI: 



,^. 



*"* 



SHO 



SPRUCE 



45 50 55 60 65 



%0F TOTAL SUGARS. FERMENTABLE 



14 16 18 20 22 45 50 55 60 65 70 



YIELD OF TOTAL SUGARS IN % 

 OF DRY WEIGHT OF WOOD 



Fig. 9.— Series V and Va, showing variation in yields of total sugar and percentage of total sugars that is 

 fermentable with varying concentrations of sulphuric acid for spruce and shortleaf pine. 



that the acidity of the solution used for hydrolysis is of minor or no 

 importance, but that the concentration of the catalytic agent ex- 

 pressed in percentage of dry wood is the decisive factor. As stated 

 previously, Simonsen expressed all of his results in total sugar. When 

 such long cooking periods are used (two hours in his work on variable 

 No. 3 — the influence of the amount of water present and of the acid 

 concentration), it is not surprising that he found variable sugar 

 yields with a constant amount of acid and varying amounts of water, 

 or varying " acidities," as he called them. ' The decomposition prod- 

 ucts so obtained would be largely reducing agents, formic and 

 lsevulinic acids, which would show high sugar yields. Practically 

 always, especially in the above work on cellulose, Simonsen used 

 amounts of water which were technically not feasible. Neuman 

 realized the technical importance of decreasing the ratio of water to 

 wood, but carried it no further than 3 to 1 — 300 per cent of water. 



