Process for the preparation of 2,2'-dichloro-hydrazobenzene

US4217307A · kind A · utility

Assignee

• Hoechst GmbH · DE

Inventors

• Siegfried Planker · Bocholt, DE
• Konrad Baessler · Frankfurt am Main, DE
• Otto Fuchs · Frankfurt am Main, DE

Key dates

• Filing date: Jul 25, 1978
• Grant date: Aug 12, 1980
• Expiry date: Jul 25, 1998

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C07C241/02
• WIPO field: Organic fine chemistry
• WIPO sector: Chemistry

Abstract

The catalytic hydrogenation of o-nitro-chlorobenzene in aqueous alkali metal hydroxide solution with addition of an aromatic non-watermiscible solvent at an elevated temperature and under pressure using a noble metal catalyst and a polycyclic quinone as a co-catalyst leads to high and well-reproducible yields of 2,2'-dichloro-hydrazobenzene when the quinone is a derivative of anthraquinone, especially a hydroxy-anthraquinone. The product is obtained in so high a quality that it can be transformed without isolation or purification into 3,3'-dichlorobenzidine.