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:
Jun. 16, 2009
Filed:
Jun. 07, 2004
Shinichi Nagao, Okayama, JP;
Masato Inari, Okayama, JP;
Jitsuo Oishi, Okayama, JP;
Kenji Nakaya, Okayama, JP;
Hiroshi Machida, Okayama, JP;
Shinichi Nagao, Okayama, JP;
Masato Inari, Okayama, JP;
Jitsuo Oishi, Okayama, JP;
Kenji Nakaya, Okayama, JP;
Hiroshi Machida, Okayama, JP;
Mitsubishi Gas Chemical Company, Inc., Tokyo, JP;
Abstract
A process for producing a high purity aromatic polycarboxylic acid (APA) by purification of a crude APA comprises: (I) aging a slurry of the crude APA in a first dispersion medium at 180 to 300° C. for 10 minutes or longer under stirring; (II) introducing the aged slurry of the APA into a column for substituting dispersion media, bringing the slurry into contact with a second dispersion medium and separating the resultant fluid into a fluid of the first dispersion medium containing impurities and a slurry of the second dispersion medium containing crystals of the high purity APA; and (III) separating the crystals of the high purity APA from the slurry of the second dispersion medium. A high purity APA having excellent hue and particle diameter can be industrially advantageously produced while the construction of the process is simplified and the consumption of energy is decreased.