40 Cellulose 



and cotton immersed in this at a temperature not exceeding 

 10 C. for 24 hours : 100 parts of cellulose yield about 175 of 

 cellulose nitrate. The hexa-nitrate so prepared is insoluble 

 in alcohol, ether, or mixtures of both, in glacial acetic acid 

 or methyl alcohol. Acetone dissolves it very slowly. This is 

 the most explosive gun cotton. It ignites at 160-170 C. 

 According to Eder the mixtures of nitre and sulphuric acid do 

 not give this nitrate. Ordinary gun cotton may contain as 

 much as 12 p.ct of nitrates soluble in ether-alcohol. The 

 hexa-nitrate seems to be the only one quite insoluble in ether- 

 alcohol. 



Penta-nitrate, C^H^C^NC^. This composition has 

 been very commonly ascribed to gun cotton. It is difficult, if 

 not impossible, to prepare it in a state of purity by the direct 

 action of the acid on cellulose. The best method is the one 

 devised by Eder, making use of the property discovered by De 

 Vrij, that gun cotton (hexa-nitrate) dissolves in nitric acid at 

 about 80 or 90 C., and is precipitated, as the penta-nitrate, by 

 concentrated sulphuric acid after cooling to o C. ; after mix- 

 ing with a larger volume of water, and washing the precipitate 

 with water and then with alcohol, it is then dissolved in ether- 

 alcohol, and again precipitated with water, when it is obtained 

 pure. 



This nitrate is insoluble in alcohol, but dissolves readily in 

 ether-alcohol, and slightly in acetic acid. Strong potash solu- 

 tion converts this nitrate into the di-nitrate C 12 H 18 O 8 (NO 3 )2. 



The tetra- and tri-nitrates (collodion pyroxyline) are 

 generally formed together when cellulose is treated with a more 

 dilute nitric acid, and at a higher temperature, and for a much 

 shorter time (13-20 minutes), than in the formation of the 

 hexa-nitrate. It is not possible to separate them, as they are 

 soluble to the same extent in ether-alcohol, acetic ether, acetic 

 acid, or wood spirit. 



