Patent ID: 6653513
Filing Date: 2003-11-25
Classification: B01J,C07C,Y02P

Abstract:
A process for producing bisphenol A, which comprises:reacting phenol with acetone in the presence of an acid ion-exchange resin as a catalyst and a cocatalyst consisting essentially of an alkyl mercaptan, wherein a concentration of an organosulfur compound in a crystallization starting material obtained by conducting the reaction under conditions that a reaction temperature is between 60 and 100Â° C., a phenol to acetone molar ratio is between 6 and 13 and an acetone to alkyl mercaptan molar ratio is between 13 and 25, distilling off unreacted acetone, by-product water and the alkyl mercaptan as the cocatalyst and further distilling off excess phenol is maintained at 200 weight ppm or less; separating the crystallization starting material into phenol adduct crystals and a crystallization mother liquor; and recycling the crystallization mother liquor, wherein a part or the whole of the crystallization mother liquor is isomerized and recycled into the crystallization starting material.