Process for the preparation of aromatic polyamines

US4061678A · kind A · utility

Assignee

• BAYER HEALTHCARE LLC · DE

Inventors

• Hartmut Knofel · Odenthal, DE
• Gunther Ellendt · Krefeld, DE

Key dates

• Filing date: Dec 29, 1975
• Grant date: Dec 6, 1977
• Expiry date: Dec 29, 1995

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y02P20/582
• WIPO field: Organic fine chemistry
• WIPO sector: Chemistry

Abstract

The instant invention is directed to a novel process for the production of aromatic polyamines. The process of the invention comprises PA1 A. condensing an aromatic amine with formaldehyde in the presence of a hydrophobic solvent and in the absence of an acid catalyst to produce a pre-condensate mixture containing the corresponding N,N'-disubstituted aminals, PA1 B. removing substantially all the water from said pre-condensate mixture to produce a first organic phase, PA1 C. extracting said first organic phase with an aqueous solution containing an acid catalyst thereby producing a second organic phase and an aqueous pre-condensate phase which contains said aminals, PA1 D. subjecting said aqueous pre-condensate phase to a rearrangement reaction thereby producing an aqueous condensation mixture containing said aromatic polyamines, PA1 E. extracting said aqueous condensation mixture with a hydrophobic solvent to provide a solvent phase and an aqueous phase which comprises an aqueous solution containing the acid catalyst as an amine salt of said aromatic amine, and said aromatic polyamines, PA1 F. recovering aromatic polyamines from said solvent phase, and PA1 G. returning said aqueou…