IMPROVED OXIDATION BY THE METHOD OF WITTEN-HERCULES FOR THE PREPARATION OF DIMETHYLTEREPHTHALATE

The invention relates to a method for the oxidation ofp-xylene and methyl ester of the p-toluic acid withoxygen-containing gases by the Witten-Hercules method for theproduction of dimethylterephthalate in at least two consecutivestages and in the presence of a catalyst. Part of the p-xylene isoxidated in at least one partial stage rich in p-xylene as well asany optional circulation products having oxidable component fromsubsequent stages of the dimethylterephthalate method in thepresence of from 5 to 30 mass % methyl ester of the p-toluic acidcompared with the oxidable mixture in the partial stage, and/or inat least a subsequent partial stage rich in methyl ester of thep-toluic acid, methyl ester of the p-toluic acid, and/or p-toluicacid, and optionally cirulation products are oxidated in thepresence of from 2 to 30 mass % of xylene compared with the sum ofthe methyl ester of the p-toluic acid and p-toluic acid.14 claims, 2 figures