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. 10, 2007
Filed:
Jan. 13, 2004
Applicants:
Tatsuyuki Kumano, Okayama, JP;
Seiji Adachi, Okayama, JP;
Hiroshi Ogawa, Okayama, JP;
Inventors:
Assignee:
Mitsubishi Gas Chemical Company, Inc., Tokyo, JP;
Primary Examiner:
Int. Cl.
CPC ...
C07C 51/235 (2006.01);
U.S. Cl.
CPC ...
Abstract
In a method of producing pyromellitic acid by liquid-phase oxidizing 2,4,5-trimethylbenzaldehyde in a water solvent with molecular oxygen, a recrystallization mother liquor separated in a recrystallization step is recycled to the oxidation step after a part of the water solvent is removed. With this method, the loss of pyromellitic acid and the oxidation catalyst can be minimized and the burden of discharging the waste water is reduced without lowering the efficiency of the liquid-phase oxidation reaction.