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:
Mar. 21, 1995
Filed:
Sep. 23, 1993
Applicant:
Inventors:
Sachio Asaoka, Yokohama, JP;
Noriyuki Yoneda, Tokyo, JP;
Kouji Sakashita, Tokyo, JP;
Tetsuo Maejima, Kiyose, JP;
Makoto Yasui, Yokohama, JP;
Akio Shindo, Yokohama, JP;
Assignee:
Chiyoda Corporation, Yokohama, JP;
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
C07C / ;
U.S. Cl.
CPC ...
568728 ; 568724 ; 568749 ;
Abstract
A high quality bisphenol A with a high purity and an excellent hue is produced from a crystalline adduct of bisphenol A and phenol by washing the adduct with specifically purified phenol, followed by decomposition of the washed adduct to separate bisphenol A. The purification is performed by a method including contacting raw material phenol with a strong-acid ion exchange resin to obtain treated phenol, and distilling the treated phenol.