Nolan and Clapham — The Utilisation of Blonomsthylaniline. 221 



ni-nitro tetryl; the nitration of a sulphuric acid solution of methyl phenyl 

 nitrosamine is distinguished by the ease and smoothness with which the reaction 

 proceeds, there being no difficult temperature control, such as is exijerienced in 

 the nitration of diniethylaniline. This is presumably in part due to the 

 exothermic nature of the reaction between methylaniline and nitrous acid. 



Our results further indicate that a satisfactory product cannot be effected 

 by the nitration of a sulphuiic acid solution of methylaniline containing 

 suiBcient nitrous acid to form the nitroso compound; in other words, the 

 preliminary isolation of the nitroso compound is necessary. Our results would 

 point to the fact that in sulphuric acid solution there is an equilibrium condition 

 between nitrous acid (or nitrosyl sulphuric acid), methylaniline, and methyl 

 phenyl nitrosamine, the equilibrium being preponderatingiy in the latter 

 direction. 



NO H OH 



CsHs - N + H2SO4 .^^ CcHs - N + 8 = 0. 



\ ^~ \ / 



CHs CH3 - N = 



Owing to the stable condition being that containing a preponderating amount 

 of methyl phenyl nitrosamine, the latter when dissolved in sulphuric acid is 

 dissociated only very slowly, and consequently can be nitrated to give a good 

 quality of tetryl, provided that reaction is carried out soon after solution of the 

 nitrosamine in sulphuric acid. When, however, the solution is allowed to stand 

 a considerable time, an appreciable amount of dissociation occurs, with the result 

 that the product gives rise on nitration to m-nitro tetryl, which is identified in 

 the form of its derivative oxy-tetryl in the waters obtained on washing the 

 product of nitration. Nitrosyl sidphuric acid acting on methylaniline in 

 sulphuric acid solution, or methyl phenyl nitrosamine dissolved in sulphuric 

 acid, gives rise to some p-nitroso methylaniline, but that this is not the cause of 

 the production of m-nitro tetryl is quite clearly established by our experiments 

 on the nitration of p-nitrosomethylaniline. 



In \dew of the above, it was thought that the most satisfactory method of 

 nitration of the nitrosamine might be to run it into a mixture of nitric acid and 

 sulphuric acid ; but under these conditions violent reaction ensued, accompanied 

 by charring at the point of entry of the nitrosamine. 



Experiment 1. — Nitration of Monometliylaniline (pure). 



Monomethylaniline (30 g.) was run into 97 per cent, sulphuric acid (300 g.), 

 with good mechanical stirring, the temperature being kept below 10° C. 

 92 per cent, nitric acid (111 g.) was warmed up to 45° C, and the sulphate 

 solution slowly added, the temperature being maintained between 50° and 55° C. 

 by means of external cooling. When about three-fourths of the sulphate solution 

 had been added, nitro body separated as an oil, which, unless vei'y vigorous 

 stirring was employed, either became a plastic material or formed into large 

 lumps. By vigorous agitation the material could, however, be obtained in a 

 semi-gramilar, semi-crystalline form. After all the sulphate solution had been 

 added, the mixture was maintained for one hour at 50-55° C. The mass was then 

 cooled to 20° C. and fitered. The acid tetryl was added to about 1-;^ litres of 

 ice cold water; it was then filtered, ground under water, filtered, washed, and 

 finally given three four-hour washings with water heated by injected steam. 

 In the first washing, when the temperature of the water reached 95° C, the whole 



