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. 23, 2001
Filed:
Nov. 12, 1999
Bayer Aktiengesellschaft, Leverkusen, DE;
Abstract
The present invention relates to a process for the continuous production of dihydroxydiarylalkanes (bisphenols) by the reaction of fresh phenol, phenol and isoalkenylphenol from the decomposition of by-products, and ketone. In this process the bulk of the bisphenol is recovered from the reaction mixture by crystallization and the mother liquor obtained is freed from phenol by distillation. The phenol is returned to the reaction and the bottoms obtained during the distillation are decomposed in a reactive rectification after addition of a basic catalyst. The phenol and isoalkenylphenol leaving at the top are led back into the reaction; the bottoms from the first reactive column are acidified and in a second reactive rectification, in the presence of an acid catalyst, are further decomposed into phenol, which distils off and is reused in the reaction, and bottoms, which are disposed of.