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Method to manufacture bisphenol A

  • US 5,198,591 A
  • Filed: 11/22/1991
  • Issued: 03/30/1993
  • Est. Priority Date: 11/24/1990
  • Status: Expired due to Fees
First Claim
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1. A process to obtain high-purity bisphenol A from a post-reaction mixture resulting from the step of synthesis from phenol and acetone, in the presence of a strong acid cation-exchanger catalyst, by way of crystallization and separation by distillation followed by recovery of bisphenol A from the step of thermal catalytic decomposition of by-products of the principal process technology in a multistage process, the by-products being selected from the group consisting of o,p isomers of bisphenol A, Dianin compound, trisphenols, polyphenols and colored substances, wherein unit (1) of the reaction system is the unit where the following reactions are conducted simultaneously:

  • reaction of phenol with acetone, reaction of phenol with recycled p-isopropenylphenol, and reactions of isomerizational rearrangement of bisphenol A isomers, at a temperature of about 60°

    -95°

    C. in the presence of a micro- and macroporous catalyst mixture, whereas the post-reaction mixture is cooled together with acetone and water to obtain a bisphenol-A/phenol slurry adduct in a phenolic solution in unit (2) and the bisphenol-A/phenol slurry adduct in a phenolic solution obtained in unit (2) is separated in unit (3) to obtain crystalline bisphenol-A/phenol adduct and phenol liquor I, whereafter the crystalline adduct is washed with phenolic solution and the crystalline bisphenol-A/phenol adduct obtained in unit (3) is dissolved in at least one of a portion of the phenol liquor I and a phenol liquor II in unit (4) and the mixture is cooled to obtain bisphenol-A/phenol adduct slurry in a phenolic solution, whereafter the slurry obtained in unit (4) is separated in unit (5) into crystalline bisphenol-A/phenol adduct and the phenol liquor II to be sent back to unit (3) while washing the crystalline bisphenol-A/phenol adduct with phenol solution, whereas the high-purity bisphenol A is separated in unit (6) by removing phenol from bisphenol-A/phenol adduct obtained in unit (5), phenol liquor I obtained in unit (3) is distilled in unit (7) by removing water and acetone and part of phenol therefrom, whereas dewartered phenol liquor is sent back to unit (1), whereafter part of the phenol liquor obtained in at least one of unit (3) and unit (7) is decomposed by thermal catalytic decomposition in unit (8) to obtain phenol-containing distillate, p-isopropenylphenol and the process by-products, while reactive components of the distillate obtained in unit (8) are rearranged catalytically in unit (9) leaving the p-isopropenylphenol contained therein substantially intact, and the rearranged distillate is sent back to unit (1) of the process of the invention.

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