Process for preparing 4-aminodiphenylamine

US6414192B1 · kind B1 · utility

Assignee

• BAYER HEALTHCARE LLC · DE

Inventors

• Michael Schelhaas
• Carl Casser · Neunburg vorm Wald, DE
• Dietmar Bielefeldt · Ratingen, DE
• Pieter Ooms · Krefeld, DE
• Joachim Haider
• Manfred Jautelat · Burscheid, DE
• Christian Laue · Monheim, DE
• Henry Giera · Wittlich, DE

Key dates

• Filing date: Nov 6, 2001
• Grant date: Jul 2, 2002
• Expiry date: Nov 6, 2021

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C07C209/38
• WIPO field: Organic fine chemistry
• WIPO sector: Chemistry

Abstract

The invention provides a process for preparing 4-aminodiphenylamine, an important starting product for synthesizing antioxidants and stabilizers in the rubber and polymer industry, by hydrogenating nitrosobenzene with hydrogen in the presence of a proton acid as catalyst and in the presence of a hydrogenating catalyst, optionally in the presence of an inert organic solvent and thermally decomposing the 4-ADPA ammonium salt produced in this way, wherein 4-ADPA is obtained.4-aminodiphenylamine is produced in good yields and high purity by the process according to the present invention. Furthermore, no effluent is produced, which makes the process particularly economic and ecological.