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. 26, 1999
Filed:
Feb. 17, 1998
Mitsui Chemicals, Inc., Tokyo, JP;
Abstract
A process for producing purified terephthalic acid capable of controlling the transmittance of the purified terephthalic acid product promptly in a simple procedure without necessitating to alter the condition of the oxidation of paraxylene to thereby permit a minute control of the process and to allow to obtain a purified terephthalic acid product with a low and constant impurity level within a certain range, which process comprises hydrogenating a crude terephthalic acid resulting from a liquid phase oxidation of paraxylene in a hydrogenation reactor 6 in the presence of a hydrogenation catalyst, followed by precipitation of the crystals 8, a solid/liquid separation 11, re-slurrying 14 of the separated crystals in water and a further solid/liquid separation 16, to obtain a purified terephthalic acid; observing the transmittance of the resulting purified terephthalic acid; and controlling the temperature of the washing water so as to maintain the observed transmittance within a predetermined range.
Data source: USPTO (United States Patent and Trademark Office) public patent records. Weekly synchronization. How IDiyas builds this profile