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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.

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