VERFAHREN ZUR HERSTELLUNG VON TEREPHTHALSAEURE

摘要

A process for the continuous preparation of pure terephthalic acid by oxidation of p-xylene with molecular oxygen in acetic acid solvent comprising conducting the oxidation at a temperature of 205 DEG to 230 DEG C. in the presence of an oxidation catalyst comprising (a) a cobalt compound in an amount of at least 120 ppm and less than 200 ppm as cobalt based on the weight of solvent, (b) a manganese compound sufficient to provide a manganese to cobalt weight ratio of 0.5 to 1.5 and (c) a bromine compound selected from hydrogen bromide, cobalt bromide and manganese bromide in an amount of 200 to 1,000 ppm as bromine based on the weight of solvent, while the water content of the liquid phase of the reaction system is kept at 4 to 14 percent by weight.