METHOD OF PRODUCING BISPHENOL A Russian patent published in 2011 - IPC C07C37/86 C07C39/16 C07C37/20 

FIELD: chemistry.

SUBSTANCE: present invention relates to a method of producing bisphenol A, which is a starting compound in producing epoxy or polycarbonate resin, involving: (A) a condensation reaction step, involving a reaction between acetone and excess phenol in the presence of an acid catalyst, (B) a concentration step, involving concentration of the reaction mixture obtained at the condensation reaction step, (C) a step for crystallisation and separation of solid/liquid phases, involving crystallisation of an adduct of bisphenol A and phenol by cooling the concentrated liquid obtained at the concentration step, and separation of the concentrated liquid into an adduct and mother liquid, (D) an isomerisation step, involving isomerisation of bis(hydroxyphenyl)propanes, different from bisphenol A, into bisphenol A, carried out by bringing all the mother liquid obtained at the step for crystallisation separation of the solid/liquid phases into contact with a strongly acidic cation-exchange resin, (E) an extraction step involving feeding through a circulation loop a portion of the isomerised liquid back to at least one step selected from (A) a condensation reaction step, (B) a concentration step and (C) a step for crystallisation and separation of the solid/liquid phases, while simultaneously extracting bisphenol A and phenol from the portion of the isomerised liquid, (F) an adduct decomposition step, involving removal of phenol from the adduct of bisphenol A and phenol and extraction of bisphenol A and (G) a granulation step, involving granulation of bisphenol A obtained at the adduct decomposition step. Concentration of water in the mother liquid, which contains bis(hydroxyphenyl)propanes, at the isomerisation step (D) is controlled by keeping it in the 0.2-0.9 wt % range.

EFFECT: method enables to prolong the service life of an isomerisation catalyst and efficiently obtain the desired product.

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