ETHYL ALCOHOL FROM WOOD WASTE. 
31 
A similar increase in formic acid is shown in the curve for series lb 
on page 50. 
As no data were available in the literature on the decomposition 
of pentoses under the conditions that obtained in these experiments, 
a number of autoclave cooks were made in which both pure dextrose 
and pure xylose in sulphuric-acid solutions were used. The solu- 
tions were made in such a way that the concentrations of sugar 
would be comparable to those obtained in the regular runs, and the 
data from these cooks are given in the two following tables : 
Solution of 0.: 
of a gram of xylose in 100 c. c. of 0.5 per cent sulphlric acid, heated to 112 pounds in 20 
minutes. Held at 112 pounds for 15 minutes. 
Original xylose grams. . 
Residual reducing sugars do 
Residual reducing sugars, per cent of original 
Acetic acid grams. . 
Formic acid do 
' 1. 
I,. 
0. 4000 
0. 4000 
.2268 
.2044 
56.7 
51.15 
None. 
None. 
.0232 
.0280 
•in. 
0. 4000 
.2056 
51.4 
None. 
Solution of 4 grams of dextrose in 100 c. c. of 0.5 per cent sulphuric acid, heated to 112 pounds in 20 minutes. 
I, held at 118 pounds for 15 minutes; II, held at 112 to 116 pounds for 15 minutes. 
I. 
II. 
III. 
Original dextrose grams. . 
Residual reducing sugars do 
1.000 
1.072 
.0046 
.0926 
2.000 
1.472 
.0070 
.0766 
Formic acid do 
In addition to the above two series, one cook was made on an 
aqueous solution of dextrose instead of a sulphuric-acid solution and 
with the following results : 
Aqueous solution of 4 grams of dextrose in 100 c. c. of solution, heated to 112 pounds in 20 minutes. Held 
at 112 pounds for 15 min utes. Reducing sugar 0.1891 gr. cu.=0.09685xi0X4=3.874 grams of dextrose 
per 100 c. c. 
Acetic. 
Formic. 
Total. 
0. 70 c. c. 
.70 c. c. 
. 00406 g. 
0.25 c. c. 
.25 c. c. 
.0011 g. 
0.95 c. c. 
.95 c. c. 
The above data confirm the experimental results obtained in cooks 
in the series mentioned and are also extremely interesting, as it is 
found that approximately 50 per cent of xylose was decomposed 
under the conditions used, even in a solution containing only 0.8 of 
a gram per 100 c. c. of 0-5 per cent sulphuric acid. Furthermore, 
only formic acid is produced, with no acetic acid whatever. A dex- 
trose solution having five times the concentration of dextrose showed 
on an average 64 per cent of the original dextrose remaining; and, 
although formic acid was the main constituent of the total volatile 
acid, some acetic acid was formed. 
