Process for the preparation of isocyanates

US8546605B2 · kind B2 · utility

Assignee

• BASF SE

Inventors

• Matthias Kloetzer · Kröppen, DE
• Eckhard Stroefer · Mannheim, DE
• Volker Krase · Schwarzheide, DE
• Andreas Schmidt · Schwarzheide, DE
• Peter Scherbel · Schwarzheide, DE

Key dates

• Filing date: Sep 5, 2006
• Grant date: Oct 1, 2013
• Expiry date: Jan 10, 2029

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C07C269/04
• WIPO field: Organic fine chemistry
• WIPO sector: Chemistry

Abstract

The invention provides a multistage process for continuously preparing organic, distillable polyisocyanates, preferably diisocyanates, more preferably aliphatic or cycloaliphatic diisocyanates, by reacting the corresponding organic polyamines with carbonic acid derivatives and alcohols to low molecular mass monomeric polyurethanes, and thermally cleaving said polyurethanes, in which at defined reaction stages the polyisocyanates prepared and unusable residues are separated off, and reusable by products and intermediates are recycled to upstream stages.