Method for preparing diisocyanates in the gas phase

US10040753B2 · kind B2 · utility

Assignee

• Covestro Deutschland AG · DE

Inventors

• Peter Lehner · Baytown, US
• Rainer Bruns · Leverkusen, DE
• Wolfgang Lorenz · Dormagen, DE

Key dates

• Filing date: Jun 7, 2016
• Grant date: Aug 7, 2018
• Expiry date: Jun 7, 2036

Classification

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

Abstract

Methods for the preparation of diisocyanates by the reaction of the corresponding primary diamines with phosgene in the gas phase are described, wherein the pressure in the diamine evaporation chamber during the transfer of the diamine into the gas phase is less than the pressure in the reaction chamber during the reaction to the diisocyanates, and wherein the pressure difference between the diamine evaporation chamber and the reaction chamber prior to the mixing of diamine and phosgene is overcome by a pressure-increasing element.