4.46 GUN-COTTON AND NITRO-CELLULOSES. 



wood-pulp associated with various nitrates, an explosive which 

 has assumed some importance recently. 



6. In the following paragraphs we shall merely treat of 

 ordinary gun-cotton alone and when with water or nitrates, 

 these three substances being regarded as types. We shall, as 

 usual, regard them chiefly with reference to the degree of heat 

 liberated, the volume of gases, and the pressures developed. 



2. NlTRO-CELLULOSES : THEIR COMPOSITION. 



1. The nitrification of cellulose under its various forms (cotton, 

 paper, straw, wood-pulp, etc.) is accomplished by means of 

 nitric acid of various degrees of concentration, with or without 

 the addition of sulphuric acid, and working at different tempe- 

 ratures. The products are numerous, and they have been the 

 object of many researches. Here we shall content ourselves by 

 reproducing the results of the most recent experiments, namely, 

 those by Vieille l carried out at 11, in the presence of an excess 

 of acid sufficient to prevent the water formed by the reaction 

 modifying the composition to any appreciable extent. 



The highest nitrification is obtained with nitro-sulphuric 

 mixtures ; it corresponds sensibly to the formula of an ende- 

 canitric cellulose 



C 21 H 18 (N0 3 H) 11 9 . 



This is gun-cotton intended for military purposes. 



With nitric acid alone, corresponding to the composition 



(N0 3 H + |H 2 0), 



and when experimenting at 11, we obtain a decanitric cellulose ; 

 that is to say, less rich in acid 



C 24 H 20 (N0 3 H) 10 10 , 



a body which is completely soluble in acetic ether, but almost 

 insoluble in a mixture of alcohol and ether. This is still gun- 

 cotton. 



When the acid is rather more diluted 



(HN0 3 + -34H 2 0), 



it yields collodion cotton, the composition of which is very 

 similar to that of the enneanitric and octonitric celluloses 

 C 24 H 22 (N0 3 H) 9 11 , and 24 H 24 (N0 3 H) 8 11 , /y 



bodies which are soluble in acetic ether and in a mixture of 

 alcohol and ether. 



With the acid N0 3 H+ iH 2 0, a cellulose is obtained which 

 answers to the characteristics of a heptanitric compound 



1 " Comptes rendus des stances de 1'Academie des Sciences," torn. xcv. 

 p. 132. 1882. 



