To obtain an aromatic dicarboxylic acid excellent in quality and color tone of polymerization while extremely preventing combustion loss of acetic acid as a reaction solvent.
An alkyl aromatic hydrocarbon (e.g. p-xylene) is oxidized in an acetic acid solvent in the presence of a catalyst containing cobalt, manganese and bromine in a liquid phase at 140-180°C to give the objective aromatic carboxylic acid. Preferably, the amount of the cobalt compound is 400-3,000wt. ppm calculated as cobalt metal based on the acetic acid solvent, the amount of the manganese component is 0.001-0.4 by the atomic ratio to cobalt and the amount of the bromine component is 0.1-5.0 by the atomic ratio to cobalt. A condensable component discharged from a reactor in the reaction is condensed and removed to give an oxidizing exhaust gas, which is partially supplied to a liquid phase of the reactor. The reaction pressure is preferably raised more than the pressure in which the oxidizing exhaust gas is neither circulated nor supplied, by using air as a molecular oxygen-containing gas.
KOMATANI TAKASHI
FUKUDA KATSUNORI
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