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:
Mar. 17, 1992
Filed:
Jun. 27, 1990
Applicant:
Inventors:
Juergen K Holzhauer, Naperville, IL (US);
George E Kuhlmann, Naperville, IL (US);
Assignee:
Amoco Corporation, Chicago, IL (US);
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
C07C / ;
U.S. Cl.
CPC ...
562487 ; 562485 ; 562486 ;
Abstract
Aromatic dicarboxylic acids, specifically 4,4'-dicarboxydiphenyl ether, terephthalic acid, 4,4'-carboxybis(benzoic acid) and the like, are purified by dissolving the crude acid in a monocarboxylic acid anhydride, purifying the resulting solution, and recovering a purified acid product therefrom.