Process for the preparation of isocyanates in the gas phase

US9365503B2 · kind B2 · utility

Assignee

• Covestro Deutschland AG · DE

Inventors

• Klaus Biskup · Leverkusen, DE
• Rainer Bruns · Leverkusen, DE
• Wolfgang Lorenz · Dormagen, DE
• Lars Padeken · Itzehoe, DE
• Bernd Pennemann · Moitzfeld, DE
• Fritz Pohl · Wittmund, DE
• Andreas Rausch · Regensburg, DE
• Friedhelm Steffens · Leverkusen, DE

Key dates

• Filing date: Dec 14, 2009
• Grant date: Jun 14, 2016
• Expiry date: Dec 14, 2029

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C07C263/10
• WIPO field: Organic fine chemistry
• WIPO sector: Chemistry

Abstract

Meta-toluene-diisocyanate is produced by reacting meta-toluenediamine with phosgene in the gas phase. The meta-toluenediamine to be vaporized for use in this phosgenation process must contain less than 0.5 wt. % of toluenediamine residue, a total of less than 0.2 wt. % of ammonia and cycloaliphatic amines, and less than 20 ppm of heavy metals. At least 0.1 wt. % of the liquid meta-toluenediamine being to be vaporized must not be vaporized. This non-vaporized content of the meta-toluenediamine must not be fed to the phosgenation reactor.