GB593576A - Improvement in manufacture of tetryl - Google Patents

Abstract

Tetryl is manufactured by passing a mixture of sulphuric acid (preferably 5-15 per cent), nitric acid (preferably 75-82 per cent) and water, preferably preheated to 140-160 DEG F., into a nitration apparatus, introducing a solution of dimethylaniline in sulphuric acid, the ratio of nitric acid to dimethylaniline being at least 7 : 1, preferably between 7 : 1 and 12 : 1, agitating the charge throughout the nitration process, maintaining the nitration temperature between 150 DEG and 180 DEG F. until at least two-thirds of the dimethylaniline solution has been added and not below 140 DEG F. during the remainder of the reaction, and thereafter recovering the tetryl, e.g. by cooling the charge and separating the crystallized tetryl by filtration, or by drowning the charge in water. The required nitration conditions may be achieved by (1) maintaining the temperature at 150-180 DEG F. throughout and feeding the dimethylaniline solution into the apparatus until a substantial portion of the nitric acid has been consumed, or (2) maintaining the temperature at 150-180 DEG F. and terminating the reaction by discontinuing the addition of dimethylaniline solution while an excess of nitric acid remains, or (3) maintaining the temperature at 150-180 DEG F. until about two-thirds of the dimethylaniline solution has been introduced and thereafter at 140-160 DEG F. The nitration mixture is advantageously maintained at 140-180 DEG F. for 10-30 minutes after the reaction is substantially complete. In an example, the acid mixture contains 10.5 per cent sulphuric acid, 78.5 per cent nitric acid and 11 per cent water and is preheated to 155 DEG F., the ratio of nitric acid to dimethylaniline is about 10 : 1, and the temperature is maintained at 160 DEG F. throughout the addition of the dimethylaniline solution and for 15 minutes thereafter.