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Process for preparing and recovering 4,4'-dihydroxy-alpha-alkylstilbene or 4,4'-dihydroxy-alpha, alpha'dialkylstilbene

  • US 5,723,693 A
  • Filed: 09/13/1996
  • Issued: 03/03/1998
  • Est. Priority Date: 09/13/1996
  • Status: Expired due to Fees
First Claim
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1. A process for preparing a 4,4'"'"'-dihydroxy-alpha-alkylstilbene or 4,4'"'"'-dihydroxy-alpha,alpha'"'"'-dialkylstilbene which comprises:

  • (A) reacting at a temperature of from -20°

    C. to 20°

    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;

    such that the mole ratio of phenolic hydroxyl group-containing or aromatic alkoxy group-containing compound(s);

    alpha-haloketone(s);

    strong protonic acid(s) or Lewis acid(s) or combination thereof is from 0.1;

    1;

    0.0026 to 20;

    1;

    8;

    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 mater 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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