Process for preparing 4-aminodiphenylamines

USRE44175E1 · kind E1 · reissue

Inventors

• Roger Keranen Rains · Broadview Heights, US
• Ralph Albert Genetti · Copley, US
• Edward Albert Lambers · Somerville, US
• Antonius Johannes van Hengstum · Deventer, NL

Key dates

• Filing date: Apr 21, 2010
• Grant date: Apr 23, 2013
• Expiry date: Apr 21, 2030

Classification

• Technology area (CPC —): General

Abstract

A process for preparing an optionally substituted 4-aminodiphenylamine comprising reacting an optionally substituted aniline and an optionally substituted nitrobenzene in the presence of water and a base while controlling the water content so as to ensure a molar ratio of water to the base charged of not less than about 4:1 at the start of the coupling reaction and not less than about 0.6:1 at the end of the coupling reaction to produce 4-nitrodiphenylamine and/or 4-nitrosodiphenylamine and/or salts thereof. The coupling reaction is followed by a hydrogenation reaction where the coupling reaction product is hydrogenated in the presence of a hydrogenation catalyst and added water so as to ensure a molar ratio of total water to base of at least about 4:1 at the end of hydrogenation. Aqueous and organic phases are obtained and the optionally substituted 4-aminodiphenylamine recovered from the organic phase.