The ion exchange resin-catalyzed condn. of PhOH with Me(2)CO to (p-OHC(6)H(4))(2)CMe(2) (bisphenol A) under recycyling the mother liq. from crystn. of the product was studied under tab. conditions in 2 serially connected packed bed continuous reactors (80 cm(3) each). The reactor and process were math. modeled by differential mass and heat transport as well as reaction rate equations under steady state conditions. The calcd. data agreed well with the operational data from an industrial plant for bisphenol A synthesis.