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:
Aug. 26, 2014
Filed:
Nov. 05, 2007
Hans-werner Michalczak, Herne, DE;
Stephan Kohlstruk, Duelmen, DE;
Manfred Kreczinski, Herne, DE;
Gerda Grund, Coesfeld, DE;
Rainer Lomoelder, Muenster, DE;
Hans-Werner Michalczak, Herne, DE;
Stephan Kohlstruk, Duelmen, DE;
Manfred Kreczinski, Herne, DE;
Gerda Grund, Coesfeld, DE;
Rainer Lomoelder, Muenster, DE;
Evonik Degussa GmbH, Essen, DE;
Abstract
The invention relates to a multi-stage process for the continuous, phosgene-free preparation of (cyclo)aliphatic diisocyanates that comprises the conversion of (cyclo)aliphatic diamines into the corresponding (cyclo)alkylene biscarbamates and the thermal cleaving of the latter into the (cyclo)alkylene diisocyanates and alcohol. The urea used in accordance with the invention and also the urea employed for the preparation of urea equivalents (e.g. alkyl carbonates, alkyl carbamates) as a possible precursor for the synthesis of the (cyclo)aliphatic biscarbamates is unconditioned.