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. 25, 2001
Filed:
Dec. 13, 1999
Gerhard Fennhof, Willich, DE;
Hans-Josef Buysch, Krefeld, DE;
Gerd Fengler, Krefeld, DE;
Tony van Osselaer, Krefeld, DE;
Bayer Aktiengesellschaft, Leverkusen, DE;
Abstract
The present invention relates to a process for the continuous production of dihydroxydiphenylalkanes (bisphenols) by the reaction of fresh phenol, and of phenol obtained from the cracking of by-products, with isoalkenylphenol and ketone. In the course of this process, the reaction mixture is worked up by distillation and a high purity bisphenol is produced. The bottom products and distillates containing the by-products are cracked under basic conditions and optionally thereafter under acidic conditions. The cracked products, which substantially consist of isoalkenylphenol and phenol, are recycled, optionally after purification, with the phenol obtained during the purification of bisphenol, to the reaction to form bisphenol, and the residue obtained from cracking is disposed of.