Compound Celluloses 145 



available for analytical purposes, and will be found fully described 

 in J. Chem. Soc. 53, 889. 



As i mgr. of lignocellulose gives approximately 0*9 c.c. CO 2 

 under ordinary conditions, it will be seen that trustworthy results 

 can be obtained with very small quantities of substance ; and as 

 the entire operation takes only a very few minutes, the method is ex- 

 tremely useful for rapid approximate analyses of products obtained 

 in the course of investigation. 



() Nitric acid. In the interaction of nitric acid with the 

 fibre-substance, in presence of sulphuric acid, it has been 

 already shown that decomposition (oxidation) supervenes after 

 a few minutes' exposure. The acid (1*5 sp.gr.) alone attacks the 

 lignocellulose still more rapidly and energetically ; as the oxi- 

 dation is of a * wholesale ' character, its investigation would not 

 throw much light upon the constitution of the fibre-substance. 

 The acid of 1-43 sp.gr. acts more gradually; there is direct 

 combination in the first instance attended by deoxidation. A 

 yellow product is obtained differing but little in weight from 

 the original, and containing 2*0-2*5 P- c *- N. With the pro- 

 gress of the oxidation there is considerable disintegration of 

 the fibre-substance and conversion into soluble derivatives, 

 but of an ill-defined character. With the dilute acid, on the 

 other hand, a very gradual resolution ensues, and the reaction 

 has been carefully investigated. The main results determined 

 are these : the lignocellulose is entirely resolved into insoluble 

 cellulose (a) and soluble derivatives of the remaining groups, 

 with a proportion of acid (HNO 3 ) equal to 25 p.ct. of the fibre- 

 substance. The specific action of the acid takes place at any 

 dilution not exceeding 30 Aq : iHNO 3 (by weight), and any 

 temperature within the range 40-100. The most convenient 

 conditions are with the acid at 7-10 p.ct. HNO 3 and temperature 

 60-80. Under these conditions there is considerable evolution 

 of gas, and of very complex composition. 



The course of the reaction may be thus described. The 



L 



