Process for the manufacture of 4,4'-diphenyl-methane diisocyanate and a mixture of diphenyl-methane diisocyanate isomers containing a small amount of uretdiones and hydrolyzable chlorine

US4294666A · kind A · utility

Assignee

• BASF SE

Inventors

• Hans J. Astheimer · Schifferstadt, DE
• Horst Brandtstaedter · Ludwigshafen, DE
• Rainer Ohlinger · Hannover, DE
• Willy van Pee · Neukirchen-Vluyn, DE
• Jaak Van Steen · Wuustwezel, BE
• Friedrich Sauer · Grünstadt, DE
• Rudolf Schmidt · Giengen an der Brenz, DE
• Siegfried Krueger · Speyer, DE

Key dates

• Filing date: Aug 15, 1980
• Grant date: Oct 13, 1981
• Expiry date: Aug 15, 2000

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C07C263/20
• WIPO field: Organic fine chemistry
• WIPO sector: Chemistry

Abstract

A process for the manufacture of 4,4'-diphenylmethane diisocyanate and a mixture of diphenylmethane diisocyanate isomers containing a controllable amount of uretdione and hydrolizable chlorine which comprises feeding crude MDI to an evaporator, condensing a head fraction in two stages in the presence of an inert gas, feeding the first stage condensate to a distillation column, producing a mixture of diphenylmethane diisocyanate isomers as an overhead, producing 4,4'-diphenylmethane diisocyanate as a side draw, and condensing each of the overhead and side draw in two stages in the presence of an inert gas.