Method for manufacture of high-purity phthalic anhydride

摘要

A method for the manufacture of high-purity phthalic anhydride, which comprises exposing crude phthalic anhydride obtained by vapor-phase catalytic oxidation of ortho-xylene to contact with a gas containing molecular oxygen at an elevated temperature in the presence of an alkali metal salt of at least one carboxylic acid selected from the group consisting of maleic acid, succinic acid and benzoic acid, and optionally a manganese-containing alloy, and subsequently subjecting the resultant reaction mixture to distillation.