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:
Feb. 20, 2001
Filed:
Oct. 15, 1999
Applicant:
Inventors:
Assignee:
Ube Industries, Ltd., Yamaguchi, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
C07C 6/976 ;
U.S. Cl.
CPC ...
C07C 6/976 ;
Abstract
A tetraester of 3,3′,4,4′-biphenyltetracarboxylic acid is advantageously prepared by a process composed of a step of dimerizing an o-phthalic diester in the presence of a catalyst comprising a powdery palladium salt having a specific surface area of at least 0.5 m,/g and a basic bidentate ligand compound and one or more steps of continuing the dimerization after supplemental addition of at least one of the powdery palladium salt and the basic bidentate ligand compound.