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. 07, 1976
Filed:
Aug. 29, 1973
Applicant:
Inventors:
Ben B Corson, Milwaukee, WI (US);
William T Gormley, Pittsburgh, PA (US);
Assignee:
Koppers Company, Inc., Pittsburgh, PA (US);
Attorneys:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
C07D / ;
U.S. Cl.
CPC ...
2603463 ; 260 / ;
Abstract
The delta-4 isomer of tetrahydrophthalic anhydride is isomerized in the presence of a catalytic amount of palladium and selected acid anhydrides that liquify the normally solid delta-4 isomer at a temperature below its melting point. This permits the isomerization to be effected at relatively low temperatures and in relatively short times to produce a mixture of isomers of tetrahydrophthalic anhydride that is in the liquid state at temperatures in the range of room temperature.