METHOD FOR PRODUCING AROMATIC CARBOXYLIC ACID

摘要

PURPOSE: Provided is a method for producing aromatic carboxylic acid by which aliphatic carboxylic acids can efficiently be separated and collected from by-products such as water and alcohols unnecessary to the reaction even when a column height of a distillation column is low and a drainage treatment is simplified by combining distillation with a membrane separation. CONSTITUTION: The method comprises the steps of (i) generating the aromatic carboxylic acid under a high temperature and pressure by carrying out a liquid-phase oxidation of an alkyl aromatic compound with an oxygen-containing gas in a reaction solvent containing the aliphatic carboxylic acids in an oxidation reactor(1) in the presence of an oxidation catalyst into the distillation column(2), (ii) refluxing the fraction containing the reaction solvent into the oxidation reactor(1), (iii) cooling the exhaust gas exhausted from the distillation column(2) at a condenser(3) to generate a condensed water, and (iv) carrying out the membrane separation of the condensed water at a membrane separation device(8) to make water and methanol permeate into a permeated liquid side(15) and to concentrate the aliphatic carboxylic acids to a concentrated liquid side(14) and collect the aliphatic carboxylic acids.