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:
Dec. 24, 1996
Filed:
Jan. 03, 1996
Hiroshi Machida, Okayama-ken, JP;
Mitsubishi Gas Chemical Company, Inc., Tokyo, JP;
Abstract
A process for producing 2,6-naphthalenedicarboxylic acid (NDCA) is disclosed. This process comprises oxidizing a 2,6-dialkylnaphthalene with a gas containing molecular oxygen in a solvent containing a lower aliphatic carboxylic acid in the presence of a catalyst comprising heavy metal compounds and a bromine compound, and is characterized in that an ester mixture containing dimethyl 2,6-naphthalenedicarboxylate (NDCM) is added to the oxidation reaction. The low boiling distillate, the high boiling still residue, and the residue of the mother liquor after recrystallization, occurring during purification of the crude NDCM, are also used as additives to the oxidation reaction. According to the present invention, NDCA with large particle size and bulk density can be obtained. Therefore, solid-liquid separation of the crystals, drying of the separated crystals and transportation of the dried crystals are made easier.