(p. 179) In distilling for furfural by the usual methods of boiling cellulosic products with condensing acids, the furfural is accompanied by volatile acids, also products of decomposition of the cellulosic complex. A series of distillations was carried out with dilute sulphuric acids of varying concentration from 10-50 H_{2}SO_{4} : 90-50 H_{2}O by weight, using barley straw as a typical cellulosic material. The distillates were collected in successive fractions, and the furfural and volatile acid determined. The results are given in the form of curves. The aggregate yields were as follows:-- Concentration of acid (H_{2}SO_{4}) p.ct. 10 15 20 30 40 50 Furfural yield p.ct. of straw 2.0 2.0 4.4 10.1 11.5 11.0 Volatile acid (calculated as acetic acid) p.ct. of straw 1.7 1.9 3.1 4.3 6.3 14.8 With acids up to 20 p.ct. H_{2}SO_{4} both products are formed concurrently and in nearly equal quantity. With the 30 p.ct. acid there is a great increase in the total furfural, and with the 40 p.ct. acid it reaches nearly the maximum obtainable with HCl of 1.06 s.g. (Tollens), in this case 12.4 p.ct. The volatile acid increases, but in less ratio; it is also produced concurrently. With 50 p.ct. H_{2}SO_{4} the conditions are changed. The total furfural is rapidly formed, whereas the volatile acid continues to be formed long after the aldehyde ceases to come over. Moreover, whereas in the previous cases it was mainly acetic acid, it is now mainly formic acid. The method was then extended to a typical series of celluloses, heated with the more concentrated acid (40-50 p.ct. H_{2}SO_{4}), with the following results: __________________________________________________ | | | | | | | Volatile acid | | | |_________________| | | | | | | | | Acetic | Formic | |________________________|_______|________|________| | | | | | | Swedish filter-paper | 0.3 | 2.7 | 17.2 | | Esparto cellulose | 12.4 | 3.2 | 16.6 | | Bleached cotton | trace | 3.1 | 13.2 | | Raw cotton (American) | -- | 5.0 | 9.4 | | Jute cellulose | 5.2 | 4.9 | 22.7 | | Beech (wood) cellulose | 6.4 | 3.5 14.6 | |________________________|_______|________|________| The tendency in the hexoses and their polyanhydrides to split off one carbon atom in the oxidised form, throws some light on the furfurane type of condensation, which is represented in the lignocelluloses. We are still without any evidence as to the possible transition of the hexoses to benzenoid compounds. Such transitions would be more easily explained on the assumption that the celluloses are composed in part of polyanhydrides of the ketoses. SPIRITUS AUS CELLULOSE UND HOLZ.