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:
Mar. 03, 1998
Filed:
Sep. 13, 1996
Robert E Hefner, Jr, Lake Jackson, TX (US);
David A Carr, Lake Jackson, TX (US);
The Dow Chemical Company, Midland, MI (US);
Abstract
A process for preparing a 4,4'-dihydroxy-alpha-alkylstilbene or 4,4'-dihydroxy-alpha,alpha'-dialkylstilbene which includes the steps of (A) reacting at a temperature of from -20.degree. C. to 20.degree. C. a mixture of: (1) at least one alpha-haloketone; (2) at least one compound containing one phenolic hydroxyl group or aromatic alkoxy group per molecule such that the mole ratio of phenolic hydroxyl group-containing or aromatic alkoxy group-containing compound(s):alpha-haloketone(s) is at least 0.1:1; and (3) either (a) at least one strong protonic acid or (b) at least one Lewis acid, or (c) any combination thereof; thereby forming a reaction product containing at least one halogen-containing bisphenol compound which, upon being dehydrohalogenated, forms a 4,4'-dihydroxy-alpha-alkylstilbene or 4,4'-dihydroxy-alpha, alpha'-dialkylstilbene; (B) reducing the acid content of the product resulting from step (A) to less than 10,000 ppm; (C) dehydrohalogenating the product obtained from step (B), thereby forming a dehydrohalogenated product containing 4,4'-dihydroxy-alpha-alkylstilbene or 4,4'-dihydroxy-alpha,alpha'-dialkylstilbene; (D) adding water to the product of step (C) in amounts sufficient to crystallize at least a portion of the, 4,4'-dihydroxy-alpha-alkylstilbene or 4,4'-dihydroxy-alpha,alpha'-dialkylstilbene and recovering the crystals and the remaining organic phase separately; (E) independently repeating steps (A), (B), and (C) to obtain a dehydrohalogenated product; (F) mixing at least a portion of organic phase obtained in step (D) with the product obtained in step (E); and (G) adding water to the mixture obtained in step (F) in amounts sufficient to crystallize at least a portion of the 4,4'-dihydroxy-alpha-alkylstilbene or 4,4'-dihydroxy-alpha,alpha'-dialkylstilbene and recovering the crystals.