Oxidation process for preparing quinacridone pigments

摘要

The present invention relates to a process of preparing quinacridone by oxidizing a 6,13-dihydroquinacridone salt corresponding to the quinacridone pigment with hydrogen peroxide as the oxidizing agent in the presence of 2,7-anthraquinone disulfonic acid as catalyst. The inventive process is economical and environmentally friendly and yields high performance quinacridone pigments in a high yield.