Process for the production of quinizarine derivatives which are disubstituted in the 5- and 8-positions by hydroxyl or chlorine

A process for the production of 5,8-dichloro- or 5,8-dihydroxyquinizarine by reacting phthalic anhydride with p-chlorophenol, which process comprises reacting p-chlorophenol and phthalic anhydride in the stoichiometric ratio of 1:1 to 1:1.5 in oleum in the presence of B.sub.2 O.sub.3, H.sub.3 BO.sub.3 or boron halide, wherein oleum and phthalic anhydride are used in the weight ratio of 1:1 to 4:1 and boron compound, calculated as boron trioxide, and phthalic anhydride are used in the weight ratio of 1:2 to 1:4, carrying out the reaction in the temprature range from 180.degree. to 220.degree. C. either continuously or discontinuously, subsequently adding 50 to 70% oleum and/or chlorosulfonic acid to the reaction medium in an amount at least twice that of the oleum employed at the start of the reaction and chlorinating the boron complex of 1,4-dihydroxyanthraquinone obtained as intermediate, direct with isolation, without a chlorinating agent, in the same reaction medium and in the temperature range from 20.degree. to 150.degree. C., and either hydrolyzing the chlorinated product by diluting the acid medium in the temperature range from 70.degree. to 110.degree. C. and isolating the 5,8-dichloroquinizarine thereby obtained or by diluting the acid medium to a concentration of 80% H.sub.2 SO.sub.4 to 25% oleum, in the temperature range from 140.degree. to 220.degree. C. and isolating the 5,8-dihydroxyquinizarine thereby obtained.