Method for producing isocyanates

US10280135B2 · kind B2 · utility

Assignee

• Covestro Deutschland AG · DE

Inventors

• Thomas Knauf · Dormagen, DE
• Dirk Manzel · Moers, DE
• Peter Plathen · Krefeld, DE
• Stefan Wershofen · Mönchengladbach, DE

Key dates

• Filing date: Sep 28, 2016
• Grant date: May 7, 2019
• Expiry date: Sep 28, 2036

Classification

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

Abstract

The invention relates to a continuously operated method for producing isocyanates by reacting the corresponding amines with phosgene. When changing the target production capacity starting from a starting state with a specified production capacity and ending with an end state with a different production capacity, the current excess phosgene at the time of the transition period between the starting state and the end state, the change of the amine mass flow beginning during said time, is at least equal to and preferably greater than the excess phosgene during the production period when the production capacity is in the starting state prior to the beginning of the transition period; and the average excess phosgene during the transition period is greater than the excess phosgene during the production period when the production capacity is in the starting state prior to the beginning of the transition period.