144 Cellulose 



The oxycelluloses obtained were soluble in alkaline solutions 

 and in nitric acid (i'43 sp.gr.). Under these more severe con- 

 ditions there is an increasing evolution of gas, and from (4) 

 75 c.c. were collected. 



In the process of oxidising with chromic acid in presence of a 

 hydrolysing acid (H 2 SO 4 ), acetic acid is formed. Oxidised by its 

 own weight of CrO 3 in presence of excess of normal sulphuric acid, 

 the fibre- substance yields from 12-13 p.ct. C 2 H 4 O 2 . 



It is evident that chromic acid oxidations of the fibre-sub- 

 stance can be controlled within any prescribed limits. From 

 the investigations, of which the above are typical series of 

 experiments, it was concluded 



(i) That the keto R. hexene groups yield most readily to 

 the action, and may in fact be selectively attacked and elimi- 

 nated ; (2) that with a net loss of weight of 10 p.ct. the ligno- 

 cellulose is converted into an oxycellulose containing 42-43 

 p.ct. carbon, and yielding the same percentage of furfural (HC1 

 distillation) as the original fibre. The furfural-yielding com- 

 plex is not, therefore, radically affected by the treatment. (3) 

 As the amount of oxygen expended (CrO 3 deoxidised) is rela- 

 tively small approximately i mol. per unit weight C 12 H 18 O 9 

 of lignocellulose and would appear to be chiefly consumed 

 in oxidising the portion passing into solution, the relatively 

 large reduction in carbon percentage of the insoluble residue is 

 due to simultaneous fixation of water. (4) It appears, in fact, 

 that the furfural- yielding complex is by such action converted 

 into an oxycellulose. 



Chromic Acid and Sulphuric Acid (Cone.). When the ligno- 

 celluloses are dissolved in concentrated sulphuric acid, the addition 

 of chromic acid determines complete combustion of the carbon to 

 gaseous products CO 2 and CO. The proportion of CO formed is 

 usually very small. As both gases, however, have the same mole- 

 cular volume, a determination of the total gas evolved gives by 

 calculation the carbon contents of the substance. The method is 



