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. 20, 2018
Filed:
May. 04, 2015
Covestro Deutschland Ag, Leverkusen, DE;
Karl-Heinz Köhler, Aachen-Brand, DE;
Ricarda Leiberich, Neu-Isenburg, DE;
Kaspar Hallenberger, Leverkusen, DE;
Korbinian Krämer, Köln, DE;
Florian Lipski, Ratingen, DE;
Henning Kahnis, Köln, DE;
Gabriel Denecker, Kalmthout, BE;
Johan Vanden Eynde, Zwijnaarde, BE;
Weerachanan Somhom, Uttaradit, TH;
COVESTRO DEUTSCHLAND AG, Leverkusen, DE;
Abstract
The invention concerns a method for producing diaryl carbonates from monophenols and phosgene or chloroformic acid aryl esters in the presence of at least one optionally substituted pyridine or the hydrochloride salt thereof as catalyst, and the recovery and reinjection thereof back into the method. The method is carried out at least partially in a liquid phase without the use of an additional solvent, the catalyst being separated by means of distillation and recovered.