INCORPORATION OF QUINACRIDONE ADDITIVES DURING QUINACRIDONE PREPARATION

摘要

This invention relates to a process for the preparation ofquinacridone pigments by(a) heating a reaction mixture comprising(i) a 2,5-dianilinoterephthalic acid, a 2,5-dianilino- 3,6 -dihydroterephthalic acid, or a 2,5-dianilino-3,6-dioxo-1,4-cyclohexadiene-1,4-dicarboxylic acid;(ii) about 0.1 to about 15 percent by weight, based oncomponent (a)(i), of one or more sulfonyl-containingderivatives of 2,5-dianilinoterephthalic acid, 2,5-dianilino-3,6 -dihydroterephthalic acid, and/or 2,5-dianilino-3,6-dioxo-1,4-cyclohexadiene-1,4-dicarboxylic acid; and(iii) about 3 to about 20 parts by weight, per part of component(a)(i), of a dehydrating agent,with the proviso that if either component (a)(i) or component (a)(ii)is a 2,5-dianilino- 3,6 -dihydroterephthalic acid or derivative thereof,reaction step (a) additionally comprises an oxidation step;(b) drowning the reaction mixture from step (a) with a liquid in whichthe quinacridone pigment is substantially insoluble; and(c) isolating the quinacridone pigment.