146 Cellulose 



lignocellulose is changed in colour to a bright yellow which 

 gradually changes to lemon yellow, and after some hours' diges- 

 tion, to white. If the digestion be interrupted at the yellow 

 stage, the fibre washed and digested with boiling alcohol, a 

 bright yellow solution is obtained ; and on driving off the 

 alcohol a gummy body is left, characterised by great instability, 

 reducing Fehling's solution in the cold, yielding furfural on 

 boiling with acids, and progressively decomposed on heating at 

 100 (in presence of water) with evolution of gaseous products. 

 The substance retains from 1-2 p.ct. N, but in a very un- 

 stable form, being entirely split off on heating with water. 

 This ill-defined product we may term, for obvious reasons, the 

 intermediate body. These results will be appreciated from 

 the following statement of the final products of the decom- 

 position. 



Lignocellulose and Dilute Nitric Acid. 



r /^ 



Svlid products : Cellulose o Oxalic acid Intermediate 



63-66 p.ct. 4'0-5*5 p.ct. body, 5*3-5*8 

 Volatile acid: Acetic acid, 14-18 p.ct. 



Gaseous products : From H NO z From fibre-substance 



N 2 O 4 . N 2 O 2 . N 2 O. N 2 . HCN CO,. CO. HCN 

 (Representing about 50 p. ct. 

 of the N of the HNO a ) 



The most notable features of the decomposition are 

 (i) As regards the HNO 3 (#) The reaction depends upon 

 the presence of nitrous acid ; the addition of urea entirely 

 arrests the specific action of the acid, and it then behaves 

 exactly as the non-oxidising mineral acids, (b) The direct 

 deoxidation of nitric acid never proceeds beyond the formation 

 of NO ; the presence of N 2 O indicates the formation of a 

 hydroxime, and its decomposition by further reaction with 

 nitrous acid. The formation of HCN also appears to result froro 

 the dehydration of a product of this nature, and this conclu- 

 sion is confirmed by the observation that HCN appears in 



