Method for synthesis of aliphatic isocyanates from aromatic isocyanates

US6924385B2 · kind B2 · utility

Assignee

• Degussa AG · DE

Inventors

• Christian Lettmann · Coesfeld, DE
• Stephan Kohlstruk · Marl, DE
• Guido Stochniol · Haltern am See, DE
• Emmanouil Spyrou · Schermbeck, DE

Key dates

• Filing date: Dec 31, 2002
• Grant date: Aug 2, 2005
• Expiry date: Dec 31, 2022

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C07C263/04
• WIPO field: Organic fine chemistry
• WIPO sector: Chemistry

Abstract

The invention relates to a method for synthesis of aliphatic isocyanates from aromatic isocyanates in substantially 3 stages. In particular, the invention relates to a method for synthesis of bis{4-isocyanatocyclohexyl}methane (H12MDI) from bis{4-isocyanatophenyl}methane (MDI). More especially, the invention relates to a method for synthesis of H12MDI with a trans-trans isomer content of <30%, preferably of <20%, particularly preferably of 5 to 15%.