Process for separation of naphthoquinone and phthalic acid

摘要

Naphthoquinone having a purity of higher than 95% is separated from an aqueous slurry of naphthoquinone and phthalic acid prepared by contacting, with an aqueous medium, a reaction mixture gas containing naphthoquinone and phthalic anhydride formed by a catalytic vapor phase oxidation of naphthalene. An extraction of naphthoquinone is carried out with a chain or cyclic saturated hydrocarbon at 60 DEG to 110 DEG C. under the condition adjusting pH to 1.2 to 5 and substantially dissolving phthalic acid in the aqueous phase and leaving resinous materials as a bottom.