Method for producing isocyanates

US9695115B2 · kind B2 · utility

Assignee

• Covestro Deutschland AG · DE

Inventors

• Rainer Bruns · Leverkusen, DE
• Wolfgang Lorenz · Dormagen, DE
• Andreas Rausch · Regensburg, DE
• Stefan Wershofen · Mönchengladbach, DE
• Tim Loddenkemper · Dormagen, DE

Key dates

• Filing date: Sep 7, 2016
• Grant date: Jul 4, 2017
• Expiry date: Sep 7, 2036

Classification

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

Abstract

The invention relates to a method for preparing isocyanates by phosgenating the corresponding amines, wherein low-boiling secondary components, excess phosgene, and the co-product hydrogen chloride are separated from the crude liquid isocyanate stream, which is obtained after the phosgenation has occurred, within a maximum of 60 minutes, and wherein the crude liquid isocyanate stream is not exposed to temperatures above 250° C. until said separation.