Crystallization processes for producing bisphenols

US7763757B2 · kind B2 · utility

Assignee

• Bayer MaterialScience AG · DE

Inventors

• Christian Münnich · Leverkusen, DE
• Ulrich Blaschke · Krefeld, DE
• Rob Eek · Bergen op Zoom, NL
• Michael Prein · Brasschaat, BE
• Raymond Audenaert · Hamme, BE
• Gert Tytgat · Duffel, BE

Key dates

• Filing date: Jan 9, 2008
• Grant date: Jul 27, 2010
• Expiry date: Jul 31, 2028

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C07C37/84
• WIPO field: Organic fine chemistry
• WIPO sector: Chemistry

Abstract

Processes for producing bisphenols (e.g., bisphenol A (BPA)) having a purity greater than 99.7% are described, such processes including reacting a phenol and acetone in the presence of an acidic catalyst to form a product mixture comprising a bisphenol; removing at least a portion of the bisphenol from the product mixture in the form of a bisphenol/phenol adduct by crystallization, filtration and washing to provide bisphenol/phenol adduct crystals; and removing at least a portion of the phenol from the bisphenol/phenol adduct crystals to provide the bisphenol having a purity of more than 99.7%; wherein the crystallization comprises continuous suspension crystallization and is carried out in at least three crystallization devices arranged such that the product mixture is first cooled in a first stage of the crystallization to a temperature of 50 to 70° C. in a first crystallization device and a second crystallization device connected in parallel, and subsequently cooled in a second stage of the crystallization to a temperature of 40 to 50° C. in a third crystallization device connected downstream in series to the first and second crystallization devices, and wherein a total dwell ti…