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. 11, 1994
Filed:
Jun. 04, 1993
Applicant:
Inventors:
Assignee:
Sumikin Chemical Co., Tokyo, JP;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
C07C / ;
U.S. Cl.
CPC ...
562488 ;
Abstract
There is disclosed a mass production process of 1,4,5,8-naphthalene tetracarboxylic acid with high collection efficiency. In the presence of an alkaline metallic catalyst, 1,3-butadiene was added to the ethyl radicals of ethyl-p-xylene, and cyclized to 1,4,5,8-tetramethyl-1,2,3,4-tetrahydronaphthalene which was further dehydrogenated and oxidized to obtain 1,4,5,8-naphthalene tetracarboxylic acid, so that a constant supply of inexpensive 1,4,5,8-naphthalene tetracarboxylic acid can be achieved as an intermediate raw material for dye, pigment, resins, or the like.