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. 03, 2001
Filed:
Mar. 30, 1999
Hiroyuki Kuwahara, Kitakyushu, JP;
Yuji Arifuku, Kitakyushu, JP;
Kazuyoshi Horibe, Kitakyushu, JP;
Nobumasa Noma, Fukuoka-ken, JP;
Masakazu Takeuchi, Yukuhashi, JP;
Haruki Kawano, Tokai, JP;
Nippon Steel Chemical Co., Ltd., Tokyo, JP;
Abstract
This invention relates to a process for purifying benzoic acid continuously to a purity of 99.9% or more by introducing crystals of crude benzoic acid with a bulk density of 0.2 g/cm,or more and an average particle diameter of 0.3 mm or more into a continuous crystallization apparatus equipped with a stirrer and a heating device from the upper portion of the apparatus, effecting counter-current contact of the falling crystals of crude benzoic acid with the melt generated by heating with the heating device, withdrawing the purified benzoic acid as melt from the lower portion of the apparatus, and withdrawing the mother liquor from the upper portion of the apparatus. The process makes it possible to prepare high-purity benzoic acid continuously in a relatively simple apparatus at high efficiency.