PURPOSE: To produce an anthraquinone compound from a para-substituted benzene and phthalic anhydride as raw materials.

CONSTITUTION: 1,4-Dimethylanthraquinone is produced from para xylene and phthalic anhydride in the presence of a heteropoly acid such as tungstophosphoric acid, tungstosilicic acid, phosphomolybdic acid or silicomolybdic acid as a catalyst. The method has such advantages that the process is simple and that installations for the production are not corroded and the method gives substituted anthraquinone compounds directly and efficiently without passing through anthraquinone.