Process for the preparation of asymmetrical N-phenyl-N'-substituted para-phenylene diamines

US4210602A · kind A · utility

Assignee

• Akzona Incorporated · US

Inventors

• Manfred Bergfeld · Zell am Harmersbach, DE
• Hans Zengel · Kleinwallstadt, DE

Key dates

• Filing date: Feb 23, 1979
• Grant date: Jul 1, 1980
• Expiry date: Feb 23, 1999

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C07C213/02
• WIPO field: Organic fine chemistry
• WIPO sector: Chemistry

Abstract

An improved process for the preparation of asymmetrical N-phenyl-N'-substituted para-phenylene diamines by the reductive alkylation of para-nitroso-diphenylhydroxylamine with an aldehyde or a ketone in the presence of hydrogen and a hydrogenation catalyst is disclosed. The improvement comprises utilizing as the hydrogenation catalyst (1) one member selected the group consisting of palladium and platinum sulfide, in an amount less than 1%, by weight, based on the weight of para-nitroso-diphenylhydroxylamine, and (2) activated carbon with a specific surface area of at least 700 square meters per gram and an ash content of less than 7.5%, by weight.