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:
Dec. 30, 2025
Filed:
Sep. 23, 2020
Covestro Intellectual Property Gmbh & Co. KG, Leverkusen, DE;
Michael Merkel, Düsseldorf, DE;
Martin Ehrig, Leverkusen, DE;
Manfred Kobylka, Burscheid, DE;
Peter Lehner, Mülheim an der Ruhr, DE;
Tim Loddenkemper, Dormagen, DE;
Martin Schiffhauer, Düsseldorf, DE;
Covestro Deutschland AG, Leverkusen, DE;
Abstract
The present invention relates to a process for distillative purification of a crude isocyanate obtained by phosgenation of the corresponding amine in a distillation apparatus under vacuum to obtain the corresponding isocyanate, characterized in that at least one liquid ring compressor is used to generate the vacuum in the distillation apparatus, a particular operating liquid is used for the at least one liquid ring compressor, the pressure p on the suction side of the at least one liquid ring compressor is 10 to 200 mbar(a), the operating temperature of the at least one liquid ring compressor is −17° C. to +15° C. and the operating liquid at the exit from the at least one liquid ring compressor has an AC value of less than 35 000 ppm, to a corresponding use of at least one liquid ring compressor for generating a vacuum in an apparatus for distillation of a crude isocyanate and to a corresponding process for operating a liquid ring compressor for providing the vacuum for distillative purification of an isocyanate obtained by phosgenation of the corresponding amine in a distillation apparatus to obtain the corresponding isocyanate.