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. 11, 2000
Filed:
Jun. 17, 1998
Applicant:
Inventors:
Shinji Ando, Tokyo, JP;
Toru Matsuura, Yokohama, JP;
Shigekuni Sasaki, Iruma, JP;
Fumio Yamamoto, Katsuta, JP;
Assignee:
Nippon Telegraph and Telephone Corp., Tokyo, JP;
Attorneys:
Primary Examiner:
Int. Cl.
CPC ...
C07D / ;
U.S. Cl.
CPC ...
549239 ; 558420 ; 562484 ;
Abstract
A method for preparing aromatic compounds including 1,4-difluoropyromellitic dianhydride represented by formula (12): ##STR1## and 1,4-difluoropyromellitic acid represented by formula (15): ##STR2## by dehydrating or hydrolyzing and dehydrating precursors.