Preparation of hexamethylene 1,6-diisocyanate and/or isomeric diisocyanates where alkylene is of 6 carbon atoms

US4613466A · kind A · utility

Assignee

• BASF SE

Inventors

• Franz Merger · Bischofswerda, DE
• Gerhard Nestler · Ludwigshafen, DE
• Friedrich Towae · Ludwigshafen, DE
• Hans Hellbach · Bischofswerda, DE

Key dates

• Filing date: Jul 15, 1985
• Grant date: Sep 23, 1986
• Expiry date: Jul 15, 2005

Classification

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

Abstract

Hexamethylene 1,6-diisocyanate and/or isomeric aliphatic diisocyanates where alkylene is of 6 carbon atoms, preferably 2-methylpentamethylene 1,5-diisocyanate and/or 2-ethyltetramethylene 1,4-diisocyanate, are prepared by a process wherein the corresponding dialkylurethanes are vaporized, without decomposition, at from 220.degree. to 300.degree. C., advantageously under reduced pressure, the dialkylurethane vapors are subjected to thermal cleavage under reduced pressure, preferably from 0.1 to 200 mbar, and at above 300.degree. C., preferably from 310.degree. to 480.degree. C. The cleavage products are fractionally condensed with the product obtained in the first condensation stage consisting predominantly of the diisocyanates, while that obtained in the second condensation stage is the alcohol.