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:
Oct. 29, 1991
Filed:
Dec. 26, 1990
Richard O Angus, Jr, Allentown, PA (US);
Khalil Yacoub, Allentown, PA (US);
Air Products and Chemicals, Inc., Allentown, PA (US);
Abstract
The present invention relates to compositions of matter corresponding to the formula: ##STR1## wherein R.sub.1 through R.sub.4, inclusive, are independently selected from a hydrogen atom, a linear or branched alkyl or alkoxy group having from 1 to about 8 carbon atoms, an alkenyl group having from 2 to about 8 carbon atoms, amino, cyano or R.sub.1 and R.sub.1, R.sub.1 and R.sub.2, R.sub.2 and R.sub.3 or R.sub.3 and R.sub.4 may together form part of a cyclohydrocarbyl ring. The subject 9,9-bis(3,4-dicarboxyphenyl)fluorene dianhydrides demonstrate utility as reactants in the preparation of polyimides used in the fabrication of membranes for separating gaseous mixtures into their respective components.
Data source: USPTO (United States Patent and Trademark Office) public patent records. Weekly synchronization. How IDiyas builds this profile