Process for removing 1,4-naphthoquinone from phthalic anhydride

US4145353A · kind A · utility

Assignee

• BAYER HEALTHCARE LLC · DE

Inventors

• Norbert Schenk
• Paul Losacker · Leichlingen, DE
• Manfred Martin

Key dates

• Filing date: Nov 10, 1977
• Grant date: Mar 20, 1979
• Expiry date: Nov 10, 1997

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C07C51/573
• WIPO field: Organic fine chemistry
• WIPO sector: Chemistry

Abstract

A process for removing 1,4-naphthoquinone from phthalic anhydride has now been found, which is characterized in that phthalic anhydride containing 1,4-naphthoquinone, or mixtures containing phthalic anhydride and also containing 1,4-naphthoquinone, are subjected to a heat treatment at temperatures from 200 .degree. to 300.degree. C. in the presence of 1,4,4a,9a-tetrahydroanthraquinone.