Phthalic Anhydride → Phthalic Acid

Participants

Reaction Conditions

Reaction Steps

A reaction mixture gas containing 5.0 wt. parts of phthalic anhydride and 2.4 wt. parts of naphthoquinone which was formed by a catalytic vapor phase oxidation, was cooled to 180° C. by a gas cooler and was introduced into the mother liquor (pH of 1.9) to obtain an aqueous slurry of naphthoquinone and phthalic acid. The slurry (pH 1.7) was heated to 85° C. to dissolve all of phthalic acid. Naphthoquinone was extracted from the slurry of naphthoquinone in a counter-current extraction with 8.0 wt. parts of xylene. The xylene phase was washed with hot water and concentrated and dried at 70° C. under a vacuum of 60 Torr to obtain 2.4 wt. parts of naphthoquinone having a purity of 96.7%.

Provenance & Evidence