A method for the production of pure, well crystallized hexa nitro diphenyl amine

摘要

2,4,6,21,41,61-Hexanitrodiphenylamine is prepared by nitrating 2,4-dinitrodiphenylamine with a nitrating acid having besides nitric acid a water content by weight of at most 25 per cent, preferably approximately 20 per cent, and a sulphuric acid content, if any, of at most 20 per cent by weight to form 2,4,21,41-tetranitrodiphenylamine, which is then nitrated with a mixture of 95 to 98 per cent concentration by weight nitric acid and sulphuric acid in which the ratio by weight HNO3 : H2SO4 is at least 3 : 1 and preferably not more than 6 : 1, e.g. approximately 5 : 1. The quantity of acid for the nitration of 2,4,21,41-tetranitrodiphenylamine may be approximately five-fold by weight as compared with the weight of the tetranitrodiphenylamine. The residual acid remaining from the second nitration, the water content of which has been brought to between approximately 20 and 25 per cent may be used for the first nitration step. Both nitration steps may be carried out at a temperature below approximately 35 DEG C., e.g. between 25 DEG and 30 DEG C. In the example, the nitrating acid in the first stage comprises by weight 65 per cent nitric acid, 14 per cent sulphuric acid, and 21 per cent water, and in the second stage a mixture of concentrated sulphuric and nitric acids both of 96 per cent concentration by weight may be used. Specifications 605,694 and 683,968, [Group III], are referred to.