PURPOSE: To obtain an aromatic carboxylic acid useful as a raw material for synthetic fibers and plastics, etc., by oxidizing an aromatic hydrocarbon having an alkyl group in the liquid phase by application of ultrasonic waves to make it possible to carry out the reaction at a higher rate and a lower temperature.
CONSTITUTION: A mixed solution of a solvent and a catalyst is filled in a reactor 1 and heated with a heater 8, and an aromatic hydrocarbon having at least one alkyl group, e.g. p-xylene, or an oxidation intermediate thereof and a gas containing O2 are introduced thereinto when the temperature reaches the reaction temperature. Ultrasonic waves at ≥10kHz are applied from an ultrasonic vibrator 10 mounted on an ultrasonic generator 11 to carry out the oxidation reaction in the liquid phase and give the aimed compound. Since the ultrasonic generator 11 is incapable of withstanding high temperatures, the generator 11 is preferably cooled to 100°C or below by a cooler 9.
EFFECT: Fine mixing not found in ordinary stirring can be carried out, and the reaction rate can be increased at low temperatures due to activation of molecules by cavitation effect.
TATE SUSUMU
CHIBA AKIRA
MITSUBISHI GAS CHEMICAL CO
MIZUSHIMA AROMA KK