Process for producing aromatic carboxylic acid

摘要

There is disclosed a process for producing an aromatic carboxylic acid (e.g.iso-or-tere-phthalic acid) by liquid-phase oxidation of an alkyl-group-substituted aromatic compound (e.g. p-or-m-xylene) in acetic acid which comprises dehydrating water-containing acetic acid by azeotropic distillation in an azeotropic distillation dehydration tower to recycle the dehydrated acetic acid as the solvent, and suppressing the concentration of the alkyl-group-substituted aromatic compound in the entrainer (e.g. n-butyl acetate) which is fed at the top portion of the above tower, to at most 10% by weight by removing the above aromatic compound. The process makes it possible to proceed with efficient dehydration of water-containing acetic acid for a long period of time by preventing the separation efficiency between acetic acid and an azeotropic component from being deteriorated by the alkyl-group-substituted aromatic compound remaining in the azeotropic component.