PRODUCTION OF AROMATIC CARBOXYLIC ACID HAVING SULFONYL GROUP

PURPOSE:To obtain the subject compound for a raw material of a polymer excellent in heat resistance and moldability at a high selectivity and in a high yield by carrying out liquid phase oxidation of a specified aromatic compound using molecular oxygen in the presence of a Co-Mn-Br-based catalyst in a prescribed ratio based on the solvent. CONSTITUTION:In oxidation of an aromatic compound [e.g. bis[4-(4- methylphenylsulfonyl)phenyl]ether] represented by the formula (R1 and R2 are H or lower alkyl; (n) is integer of 0-4 in case R1 and R2 are not H) by molecular oxygen in a fatty carboxylic acid solvent, a Co-Mn-Br-based catalyst composed of a Co compound of 0.10-0.17 pts.wt. calculated as Co metal, an Mn compound of 0.0007-0.0018 pts.wt. calculated as Mn metal and a Br compound of >=0.0465 pts.wt. calculated as Br atom based on 100 pts.wt. solvent is used as a catalyst, thus efficiently producing the subject compound of high purity, i.e., at a high selectivity.