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:
Apr. 30, 1996
Filed:
Mar. 31, 1995
Applicant:
Inventors:
Willis T Schwartz, Grand Island, NY (US);
Frank J Dinan, Tonawanda, NY (US);
Jeffrey S Stults, West Lafayette, IN (US);
Assignee:
Occidental Chemical Corporation, Niagara Falls, NY (US);
Attorneys:
Primary Examiner:
Int. Cl.
CPC ...
C07D / ; C07D / ;
U.S. Cl.
CPC ...
549234 ; 549359 ;
Abstract
Crude mixtures of dioxydiphthalic anhydride containing alkali metal salts are purified by treating the crude mixture with an alkanol, such as n-butanol, to form the dioxydiphthalic acid diester; removing the insoluble alkali metal salts by filtration; removing the excess alkanol; and reconverting the dioxydiphthalic acid diester to dioxydiphthalic anhydride.