Process for preparing organic monoisocyanates

US6664415B2 · kind B2 · utility

Assignee

• BAYER HEALTHCARE LLC · DE

Inventors

• Martin Brahm · Siegen, DE
• Lutz Schmalstieg · Neunburg vorm Wald, DE
• Ulrich Geron · Plaidt, DE
• Hans Behr · Stuttgart, DE
• Jörg Morawski · Leichlingen, DE

Key dates

• Filing date: Apr 30, 2001
• Grant date: Dec 16, 2003
• Expiry date: May 23, 2021

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C07C263/16
• WIPO field: Organic fine chemistry
• WIPO sector: Chemistry

Abstract

The present invention relates to a process for preparing a low boiling monoisocyanate having a boiling point of between 70 and 320° C. at standard pressure by reactingA) a high boiling isocyanate compound having a boiling point of at least 180° C. at standard pressure and an HC content of at least 50 ppm withB) a monoamine having a primary amino group,at a maximum reaction temperature of 180° C. and a molar ratio of isocyanate groups to amino groups of at least 4:1 to form a compound containing a biuret/urea group, simultaneously thermally decomposing this compound in situ to form a monoisocyanate corresponding to monoamine B) and removing the monoisocyanate by distillation, optionally under vacuum.