Method for producing bisphenol-A

US6414198B1 · kind B1 · utility

Assignee

• BAYER HEALTHCARE LLC · DE

Inventors

• Rolf Lanze · Krefeld, DE
• Rainer Neumann · Krefeld, DE
• Steffen Kuhling · Meerbusch, DE
• Frieder Heydenreich · Düsseldorf, DE
• Tony van Osselaer · Krefeld, DE

Key dates

• Filing date: Jun 21, 2001
• Grant date: Jul 2, 2002
• Expiry date: Jun 21, 2021

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C07C37/74
• WIPO field: Organic fine chemistry
• WIPO sector: Chemistry

Abstract

A process of preparing bisphenol A having low residual contents of oxygen and phenol is described. The process involves: (a) melting mixed crystals of bisphenol A and phenol under a nitrogen atmosphere at a temperature of 100&deg; C. to 120&deg; C.; (b) feeding continuously the melt formed in step (a) into the top of a distillation unit under conditions of 120&deg; C. to <160&deg; C. and a pressure of >80 mbar to 200 mbar; (c) feeding contemporaneously with step (b) nitrogen into the bottom of the distillation unit; (d) allowing the melted feed material and the nitrogen feed to contact each other within the distillation unit, thereby forming a concentrated melt material having (i) a phenol content reduced to 10 to 25 wt. %, and (ii) a reduced oxygen content (e.g., an oxygen content of <1 ppm); and (e) optionally passing a stream of nitrogen through the concentrated melt material under conditions of at least atmospheric pressure, 180&deg; C. to 220&deg; C. and a nitrogen partial pressure of 1 to 1.5 bar, thereby removing residual phenol from the concentrated melt material (e.g., resulting in a phenol content of <50 ppm). The melted material having reduced oxygen and phenol contents …