Method for diisocyanate recovery from distillation residues with bitumen

US12139447B2 · kind B2 · utility

Assignee

• Covestro Deutschland AG · DE

Inventors

• Anna-Marie Zorn · Ettlingen, DE
• Thomas Guttmann · Langenfeld, DE
• Claudine Stoye · Cologne, DE
• Sascha Tadjbach · Moitzfeld, DE
• Thomas Voigt · Export, US
• Irene Cristina Latorre Martinez · Leverkusen, DE
• Joerg Morawski · Leverkusen, DE

Key dates

• Filing date: Jul 15, 2019
• Grant date: Nov 12, 2024
• Expiry date: Jul 11, 2041

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C07C2602/10
• WIPO field: Chemical engineering
• WIPO sector: Chemistry

Abstract

The invention relates to a method for recovering a diisocyanate which is solid at room temperature from a distillation residue from a process for producing the diisocyanate, comprising the following steps: (i) mixing the distillation residue with a bitumen such that a mixture is obtained which contains 70 to 90 wt % of the distillation residue and 10 to 30 wt % of the bitumen, each in relation to the mixture, (ii) distilling the mixture in a thin-film evaporator or a falling film evaporator to obtain a sump discharge and a gaseous product stream, (iii) condensing the gaseous product stream and obtaining a solid containing the diisocyanate which is solid at room temperature. The invention further relates to the use of a thin-film evaporator or falling film evaporator, to a composition containing the diisocyanate which is solid at room temperature, and to a method for producing an elastomer from this composition and to the elastomer itself.