2832-30-6Relevant articles and documents
Process for the production of quinizarine derivatives which are disubstituted in the 5- and 8-positions by hydroxyl or chlorine
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, (2008/06/13)
The invention relates to a process for the production of 1,4,5,8-tetrahydroxyanthraquinone or 5,8-dichloro-1,4-dihydroxyanthraquinone by reacting phthalic anhydride with p-chlorophenol in oleum and in the presence of a boron catalyst, to give the quinizarine boron complex, and chlorinating this boron complex direct with a chlorinating agent, in the same reaction medium, to give the boron complex of dichloroquinizarine, and subsequently hydrolyzing this chlorinated boron complex to 1,4,5,8-tetrahydroxyanthraquinone or 5,8-dichloro-1,4-dihydroxyanthraquinone. The novel process is environmentally and economically more advantageous than the sum of each of the individual process steps.