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:
Aug. 28, 2018
Filed:
Oct. 02, 2017
The United States of Americas As Represented BY the Administrator of Nasa, Washington, DC (US);
Chun-Hua Chuang, Brecksville, OH (US);
Abstract
A method for preparing asymmetric 3,4'-(hexafluroisopropylidene) dipthalic anhydride (a-6FDA) and asymmetric 3,4′-(methylene)diphthalic anhydride (a-MDPA) from asymmetric 2,3,3′,4′-benzophenone dianhydride (a-BTDA). First, a-BTDA is converted to its corresponding N-alkyl or N-phenyl bisimides by reacting with either methylamine or aniline. The sequential addition of two trifluoromethyl (CF) groups to the carbonyl unit of a-BTDA produce the corresponding bisimides of asymmetric 6FDA, which is hydrolyzed to the asymmetric 6F-tetracarboxylic acid followed by cyclodehydration to obtain asymmetric 6F-dianhydride (a-6FDA). Separately, the carbonyl unit of bisimides of a-BTDA is reduced to a methylene unit to afford the corresponding bisimides of asymmetric 3,4′-(methylene)diphthalic anhydride, which is hydrolyzed to the asymmetric methylene tetracarboxylic acid followed by cyclodehydration to obtain 3,4′-(methylene)diphthalic anhydride (a-MDPA).
Data source: USPTO (United States Patent and Trademark Office) public patent records. Weekly synchronization. How IDiyas builds this profile