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:
Sep. 04, 1990
Filed:
Mar. 09, 1989
Mitsui Toatsu Chemicals, Inc., Tokyo, JP;
Abstract
A method for preparing high-purity bisphenol A which comprises a principal process comprising a first reaction step for reacting phenol with acetone, a first concentration adjusting step, a first crystallization step for precipitating crystals of the adduct of bisphenol A with phenol, a first separation step for separating a solution containing the crystals of the adduct into the crystals and the mother liquor and a phenol removing step for removing phenol from the crystals of the adduct; and a sub-process comprising a second reaction step for reacting p-isopropenylphenol with phenol, a second concentration adjusting step, a second crystallization step, a second separation step for separating a solution containing the second any crystals of the adduct into the second any crystals and the second mother liquor and a cleaving step, the first mother liquor from the principal process being fed to the sub-process and the second any crystals of the adduct from the sub-process being fed to the principal process, is herein provided. In addition, a method for preparing high-purity bisphenol A which comprises a principal process comprising a first reaction/catalyst removing step for reacting phenol with acetone and removing the catalyst, a crystallization step for precipitating the adduct of bisphenol A with phenol, a solid-liquid separation step for separating the reaction solution into the crystals of the adduct and the mother liquor and a phenol removing step for removing phenol from the adduct crystals; and a sub-process comprising a second reaction/catalyst removing step for reacting p-isopropenylphenol with phenol and removing the catalyst, a second phenol removing step, a distillation step for separating bisphenol A and low boiling and high boiling substances and a cleaving step, the mother liquor from the principal process being fed to the sub-process and the distilled bisphenol A from the sub-process being fed to the principal process, is also herein provided.