Process for the preparation of organic pigments

摘要

The prepn. of quinacridone pigments comprises: (a) heating a reaction mixt., at 80-145[deg]C, which consists of: (i) 2,5-dianilino-terephthalic acid or its deriv. having one or more substits. in at least one aniline ring; (ii) 2-10 pts. wt. per pt. wt. of component (a)(i) of a dehydrating agent; and (iii) 0.01-10 wt.%, relative to component (a)(i), of a non-iron salt; (b) drowning the reaction mixt. from step (a) by adding it to 3-15 pts. wt. of a liq. in which the pigment is largely insoluble; (c) isolating the quinacridone pigment; and opt. (d) conditioning the quinacridone pigment.