Process for the production of diurethanes and their use for the production of diisocyanates

US5744633A · kind A · utility

Assignee

• BAYER HEALTHCARE LLC · DE

Inventors

• Oswald Wilmes · Recklinghausen, DE
• Eberhard Konig · Kronberg, DE
• Klaus Nachtkamp · Cologne, DE
• Ernst Kysela · Bensberg, DE

Key dates

• Filing date: Dec 2, 1994
• Grant date: Apr 28, 1998
• Expiry date: Dec 2, 2014

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C07C269/04
• WIPO field: Organic fine chemistry
• WIPO sector: Chemistry

Abstract

A new process for the production of high purity (cyclo)aliphatic diurethanes from (cyclo)aliphatic diamines, alcohols and urea in a multistep reaction in which (1) urea is reacted with alcohol with elimination of ammonia, (2) diamine is then introduced into the reaction mixture, optionally in the form of a solution in alcohol, and reacted with continuous release of ammonia and (3) the reaction mixture is freed from volatile components by distillation. The diurethanes produced by this process are useful as starting materials for the production of the corresponding diisocyanates by thermal urethane cleavage.