Process for preparation of anthraquinones and fluorenones

Abstract

A process is disclosed for producing cyclized aromatic compounds by the liquid-phase air oxidation of 2-methyl-substituted biphenyls and diphenylmethanes in an acetic acid medium in the presence of a cobalt-manganese-bromine catalyst or a zirconium-cobalt-manganese-bromine catalyst wherein the mole ratio of cobalt-to-manganese is about 1.0:0.1 to about 1.0:10.0 and the ratio of zirconium-to-cobalt is about 0.005:1.0 to about 0.20:1.0, and mole ratio of bromine to total metals of said cobalt-manganese-bromine catalyst or zirconium-cobalt-manganese-bromine catalyst is from about 0.2:1.0 to about 20.0:1.0, which process comprises conducting the reaction in a batch process at a temperature of from 75.degree. C. to about 250.degree. C. at a pressure of from 1 to 100 atmospheres, or continuously in two stages comprising a first-stage reaction at a temperature of about 75.degree. C. to about 200.degree. C. and a second-stage reaction at a temperature of about 150.degree. C. to about 250.degree. C. and recycling the cobalt-manganese catalyst or the zircnium-cobalt-manganese catalyst by oxalate precipitation of the catalyst at temperatures of about 110.degree. C. to about 200.degree. C. prior to the separation of mother liquor and using about 0.25 to about 2.5 moles of oxalic acid per mole of cobalt and manganese or mole of zirconium-cobalt-manganese and continuously recycling the recovered catalyst metals to the oxidation stages. The products of this novel process, anthraquinones and fluorenones, are useful for the manufacture of dyestuffs and pharmaceuticals.