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:
Jul. 27, 2010
Filed:
Jan. 09, 2008
Christian Münnich, Leverkusen, DE;
Ulrich Blaschke, Krefeld, DE;
Rob Eek, HongKong, CN;
Michael Prein, Krefeld, DE;
Raymond Audenaert, Hamme, BE;
Gert Tytgat, Duffel, BE;
Christian Münnich, Leverkusen, DE;
Ulrich Blaschke, Krefeld, DE;
Rob Eek, HongKong, CN;
Michael Prein, Krefeld, DE;
Raymond Audenaert, Hamme, BE;
Gert Tytgat, Duffel, BE;
Bayer Material Science AG, Leverkusen, DE;
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 time of the product mixture in the crystallization is more than 4 hours.