Process for preparing polyisocyanates by the adiabatic phosgenation of primary amines

US8097751B2 · kind B2 · utility

Assignee

• Bayer MaterialScience AG · DE

Inventors

• Daniel Koch · Shanghai, CN
• Spotswood Miller · Friendswood, US
• Ricardo Serra · Krefeld, DE
• Dietmar Wastian · Dormagen, DE
• Jurgen Kirsch · Cologne, DE
• Gerhard Wegener · Mettmann, DE

Key dates

• Filing date: Jun 30, 2005
• Grant date: Jan 17, 2012
• Expiry date: Jan 22, 2029

Classification

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

Abstract

A two-stage process for the preparation of organic isocyanates by reacting primary amines with phosgene in which: a) in a first stage, amine and phosgene are reacted in an adiabatically managed reaction, in which the temperature of reaction is restricted to values between 100 and 220° C. by actively adjusting the absolute pressure in the reactor to values between 8 and 50 bar by decompression, and the temperature is held at values between 100 and 220° C. until the stoichiometric conversion of phosgene has reached at least 80%; and then b) in a second stage, the reaction mixture from a) is decompressed to an absolute pressure of 1 to 15 bar and the reaction mixture is reacted further at temperatures between 90 and 240° C., optionally with the introduction of heat.