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:
Sep. 06, 1994
Filed:
Aug. 06, 1993
Applicant:
Inventors:
Norbert Schon, Krefeld, DE;
Hans-Josef Buysch, Krefeld, DE;
Paul Wagner, Dusseldorf, DE;
Reinhard Langer, Krefeld, DE;
Assignee:
Bayer Aktiengesellschaft, Leverkusen, DE;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
C07C / ;
U.S. Cl.
CPC ...
558274 ; 558270 ; 203 38 ;
Abstract
Diaryl carbonates are prepared from dialkyl carbonates and phenolic compounds by transesterification in the presence of a transesterification catalyst at 60.degree.-320.degree. C. in an apparatus composed of two columns in a continuous procedure. In the first column, the starting materials form essentially the associated alkyl aryl carbonate, from which, in the second column, the diaryl carbonate is produced by further transesterification and disproportionation.