STAGED CATALYST ADDITION FOR CATALYTIC LIQUID PHASE OXIDATION OF PSEUDOCUMENE TO TRIMELLITIC ACID

摘要

Reduced tendency for oxidation inhibition leading to formyl phthalic acids and methyl phthalic acids during liquid phase oxidation of 1,2,4-trimethylbenzene with molecular oxygen in the presence of acetic acid and catalysis provided by a source of bromine and staged use of two or more heavy metals is further reduced by staging addition of cobalt, manganese and cerium by maintaining a weight ratio of bromine to total metals above 1.0 in all stages and conducting the oxidation at a temperature in the range of 360 DEG -440 DEG F. with the last stage above 400 DEG F. At the same time reduced oxidation of acetic acid to oxides of carbon and water and reduced requirements for total metal and bromine sources are achieved without sacrifice of reaction time or yield and quality of trimellitic acid.