56 Cellulose 



followed by copious washing. Failure to remove the acid, 

 even the last traces, results in disintegration or ' tendering ' of 

 the fabric on drying. 



(b} Decompositions of Cellulose by Oxidants. It 

 has been already pointed out that cellulose is comparatively 

 resistant to the action of oxidants ; that most of the processes 

 for isolating or purifying (bleaching) cellulose depend, per 

 contra^ upon the use of oxidising agents, which readily attack 

 the 'impurities' with which it is combined or mixed in raw 

 fibrous materials. The cellulose resists the action of these 

 oxidising agents, and, further, withstands in a high degree the 

 action of atmospheric oxygen. It is this general inertness of 

 the compound which marks it out for the unique part which it 

 plays in the vegetable world and in the arts. 



It must be again noted that this high degree of resistance to 

 hydrolysis (alkaline) and oxidation belongs only to cotton cellulose 

 and to the group of which it is the type, and which includes the 

 celluloses of flax, rhea, and hemp. A large number of celluloses, 

 on the other hand, are distinguished by considerable reactivity, 

 due to the presence of * free ' CO groups, and are therefore more 

 or less easily hydrolysed and oxidised. The ' celluloses ' of the 

 cereal straws and esparto grass are of this type, and hence the 

 relative inferiority of papers into the composition of which they 

 enter. (J. Chem. Soc. 1894,472.) 



On the other hand, we have now to study those processes 

 of oxidation to which it yields more or less readily. 



A. OXIDATION IN ACID SOLUTIONS. (i) Nitric acid 

 (i*i-i*3 sp.gr.) attacks cellulose at 80-100, at first slowly, 

 then more rapidly, but tending to a limit at which the action 

 again becomes very slow. This limit corresponds with the 

 formation of a characteristic product of oxidation oxycellulose. 

 This substance, which is white and flocculent, when thrown 

 upon a filter and washed with water, combines with the latter to 

 form a gelatinous hydrate. It requires, therefore, to be rapidly 



