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. 19, 1983
Filed:
Mar. 16, 1981
Jacques D Hanotier, Lasne Chapelle St. Lambert, BE;
Jacques F Dauby, Groot-Bijgaarden, BE;
Labofina, S.A., Brussels, BE;
Abstract
Disclosed is a process for the purification of a crude terephthalic acid product contaminated with up to 10% by weight of partially oxidized impurities including p-toluic acid and 4-carboxybenzaldehyde, comprising the steps of dissolving the crude product in water by heating up to a temperature at least about 5.degree. C. higher than necessary for having the resulting solution saturated with terephthalic acid; cooling the resulting solution down to a temperature not lower than about 185.degree. C. to precipitate purified crystals; recovering the purified crystals by solid-liquid separation at a temperature not lower than that used for the precipitation of the purified crystals; and washing the recovered crystals by contacting with water at a temperature which is at least as high as the temperature of the recovery step.