GB1399407A - Process for the production of rho- and my-phenylenediamine - Google Patents

Abstract

1399407 p- and m-Phenylene diamines AKZO NV 30 March 1973 [1 April 1972] 15440/73 Heading C2C The invention comprises a process for the production of unsubstituted or substituted p- or m-phenylene diamines of the general formula in which X, X<SP>1</SP>, X<SP>11</SP> and X<SP>111</SP> may be the same or different from each other and A, B, C and D may be the same or different from each other, X, X<SP>1</SP>, X<SP>11</SP> and X<SP>111</SP> representing a chemical bond or a C 1 -C 6 alkylene group and A, B, C and D representing a hydrogen or halogen atom, a C 1 -C 6 alkyl group, an aromatic or heterocyclic group or a nitro, sulphonic acid, sulphonate, hydroxyl, alkoxy, cyano, amino, monoalkyl or monoalkylamino or monoarylamino, dialkylamino, phosphoric acid, phosphate, acyl or carboxylate group, in which the correspondingly substituted terephthalic or isophthalic acids of the general formulae in which the groups X, X<SP>1</SP>, X<SP>11</SP> and X<SP>111</SP> and A, B, C and D have the meanings indicated above are reacted with a dihydric or polyhydric alcohol or with a bisphenol or with mixtures thereof in the presence of catalysts to produce an oligomeric low molecular weight polymerization product, which product is reacted in a second stage of the process with ammonia which contains up to 15% by weight of water to produce a dicarboxylic acid diamide which is then subjected to Hofmann degradation in a third stage of the process. Suitable catalysts referred to above are, for example, the salts of lithium, calcium, zinc or manganese with weak carboxylic acids. Antimony trioxide has been found to be particularly suitable even in the absence of an esterification catalyst.