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:
Jul. 17, 1990
Filed:
Aug. 31, 1989
Applicant:
Inventors:
Yakudo Tachibana, Tokyo, JP;
Kazuhiko Tate, Tokyo, JP;
Toshifumi Suzuki, Tokyo, JP;
Kouji Chiba, Miura, JP;
Assignee:
NKK Corporation, Tokyo, JP;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
C07C / ; C07C / ; C07C / ;
U.S. Cl.
CPC ...
562481 ; 562423 ; 562482 ; 562483 ; 562486 ; 562488 ;
Abstract
A method of manufacturing an alkali metal salt of 2,3,6,7-naphthalenetetracarboxylic acid. Either a sodium salt or a mixture of sodium salt and potassium salt of at least one naphthalenecarboxylic acid selected form the group consisting of naphthoic acids and naphthalenepolycarboxylic acids is heated to an elevated temperature in an inert gas atmosphere in the presence of a Henkel reaction catalyst and halogenated sodium.