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:
Jun. 03, 2008
Filed:
Jul. 19, 2007
Chun-hua Chuang, Brecksville, OH (US);
Chun-Hua Chuang, Brecksville, OH (US);
The United States of America as represented by the Secretary of the Navy, Washington, DC (US);
Abstract
This invention relates to the compositions and processes for preparing 2,3,3',4′-tetramethylbenzophenone and asymmetrical dianhydrides such as 2,3,3′,4′ benzophenone dianhydride (a-BTDA), and 3,4′-(hexafluoroisopropylidene)diphthalic anhydride (a-6FDA). a-BTDA is prepared by Suzuki coupling with catalysts from a mixed anhydride of 3,4-dimethylbenzoic acid and 2,3-dimethylbenzoic acid with a respective 2,3-dimethylphenylboronic acid and 3,4-dimethyl phenylboronic acid to form 2,3,3′,4′-tetramethylbenzophenone which is oxidized to 2,3,3′,4′-benzophenonetetracarboxylic acid followed by cyclodehydration to obtain a-BTDA. The a-6FDA was prepared by nucleophilic trifluoromethylation of 2,3,3′,4′-tetramethylbenzophenone with trifluoromethyltrimethylsilane to form 3,4′-(trifluoromethylmethanol) bis(o-xylene) which is converted to 3,4′-(hexafluoroisopropylidene-bis(o-xylene). The 3,4′-(hexafluoroisopropylidene)-bis(o-xylene) is oxidized to the corresponding tetraacid followed by cyclodehydration to yield a-6FDA.