The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Nov. 22, 2011
Filed:
Sep. 30, 2010
Wolfgang Lorenz, Dormagen, DE;
Lars Padeken, Dusseldorf, DE;
Bernd Pennemann, Bergisch Gladbach, DE;
Friedhelm Steffens, Leverkusen, DE;
Lothar Weismantel, Bergisch Gladbach, DE;
Wolfgang Lorenz, Dormagen, DE;
Lars Padeken, Dusseldorf, DE;
Bernd Pennemann, Bergisch Gladbach, DE;
Friedhelm Steffens, Leverkusen, DE;
Lothar Weismantel, Bergisch Gladbach, DE;
Bayer MaterialScience AG, Leverkusen, DE;
Abstract
The present invention relates to a process for the preparation of toluene-diisocyanate. In this process, toluenediamine is reacted with phosgene to give crude toluene-diisocyanate, the crude toluene-diisocyanate is purified by distillation, the distillation residue formed during the distillation is hydrolysed at temperatures of less than 230° C. under absolute pressures of less than 30 bar, and the toluenediamine formed by this process is subsequently recycled into the reaction of toluenediamine and phosgene.