Process for preparing methylenedianiline and methylenebis(phenyl isocyanate)

US6831192B2 · kind B2 · utility

Assignee

• BASF SE

Inventors

• Eckhard Ströfer · Mannheim, DE
• Jan Jacobs · Hoogerheide, NL
• Wilfried Seyfert · Bad Dürkheim, DE
• Hans Volkmar Schwarz · Waterloo, BE
• Olaf Schweers · Ludwigshafen, DE
• Volker Scharr · Senftenberg - Zły Komorow, DE
• Ulrich Penzel · Lauscha, DE

Key dates

• Filing date: May 21, 2002
• Grant date: Dec 14, 2004
• Expiry date: May 21, 2022

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C07C263/10
• WIPO field: Organic fine chemistry
• WIPO sector: Chemistry

Abstract

A process for preparing methylenedianiline by reacting aniline with formaldehyde in the presence of acid catalysts comprising, in a semicontinuous process, introducing aniline with or without acid catalyst, feeding formaldehyde with or without acid catalyst through a mixing element into a circuit in which aniline with or without acid catalyst and with or without previously added formaldehyde is circulated and, after feeding in at least 50% of the total amount of formaldehyde to be fed in, heating the reaction mixture to a temperature above 75° C.In addition, the invention relates to a process for preparing polyisocyanates by phosgenation of amines obtainable in this manner and to the polyisocyanates obtainable by this process.