Method for continuous production of dihydroxydiarylalkanes

US6307111A · kind A · utility

Assignee

• BAYER HEALTHCARE LLC · DE

Inventors

• Gerhard Fennhoff · Willich, DE
• Hans-Josef Buysch · Krefeld, DE
• Gerd Fengler · Krefeld, DE

Key dates

• Filing date: Nov 12, 1999
• Grant date: Oct 23, 2001
• Expiry date: Nov 12, 2019

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y02P20/10
• WIPO field: Organic fine chemistry
• WIPO sector: Chemistry

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.