[812] THE USE OF ANILINE AS AN ABSORB- 

 ENT OF CYANOGEN IN GAS ANALYSIS 1 



IN a paper published in the "Comptes Rendus," 100, 

 1005, some time ago, Jaquemin proposed the use of aniline 

 as an absorbent for cyanogen in quantitative gas analysis, 

 without, however, giving details of any experiments as to the 

 trustworthiness of the method. The proposal is a surprising 

 one, considering that hydrogen cyanide is always formed in 

 the preparation of cyananiline; this fact is distinctly stated 

 by Hofmann, 2 who accounted for its production by certain 

 secondary reactions which he studied. It is also to be noted 

 that Jaquemin, in the same paper, describes a very satisfac- 

 tory method of preparing cyanogen gas in the wet way, and 

 that he probably employed the moist cyanogen in his experi- 

 ments with aniline. As the presence of water seems to favor 

 most of the reactions of cyanogen, there did not seem to be 

 any conclusive evidence that dry cyanogen would be totally 

 absorbed by aniline. At all events, it seemed worth while to 

 make the experiment with cyanogen prepared in the old way, 

 and at the same time to ascertain to what extent the develop- 

 ment of hydrocyanic acid would interfere with Jaquemin's 

 proposed method for gas analysis. For this purpose, cyano- 

 gen prepared from dry mercuric cyanide was brought into 

 contact with recently distilled aniline. The gas was, indeed, 

 absorbed rapidly and completely, nor did a bubble of gas 

 appear after twenty-four hours' standing. But as soon as car- 

 bon dioxide was passed in, the presence [813] of hydrocyanic 



1 Reprinted from Journal of the Chemical Society, 63, 812 (October, 1888). 



2 Hofmann, Annalen, 66, 129 (1848). 



