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:
Jan. 13, 1981
Filed:
May. 23, 1979
Applicant:
Inventors:
Assignee:
Bayer Aktiengesellschaft, Leverkusen, DE;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
C07D / ;
U.S. Cl.
CPC ...
2603463 ; 260546 ; 2603466 ; 2603467 ;
Abstract
A process for the preparation of hexahydrophthalic acid anhydride which comprises hydrogenation .DELTA..sup.4 -tetrahydrophthalic acid anhydride in the liquid phase at a temperature of from 70.degree. to 150.degree. C. and at a pressure of from 30 to 200 bar in the presence of a catalyst selected from palladium, ruthenium, nickel or mixtures thereof arranged in a fixed bed, wherein the catalyst is applied to a carrier of alumina of which at least 20% by weight has been converted into lithium aluminium spinel and the liquid phase is a mixture of .DELTA..sup.4 -tetrahydrophthalic acid anhydride and hexahydrophthalic anhydride in a proportion by weight of from 1:1 to 1:100.