Kinetic study of adductive crystallization of bisphenol-A

Kinetics of adductive crystallization of bisphenol-A (BPA) from a pure phenolic solution was investigated by model fitting to experimental data. BPA is an organic compound with vast applications in manufacturing of epoxy resins and polycarbonates; and adductive crystallization is used in industry to separate BPA from the reaction mixture of BPA synthesis. Using kinetic equations and mass and population balances the adductive crystallization process of BPA was modeled. Solid and liquid information was obtained from a set of crystallization experiments carried out under a cooling program. A genetic algorithm was applied to optimize the kinetic parameters of nucleation and growth rate equations. The nucleation rate equation for crystallization of BPA–phenol adduct from a pure synthetic solution was B0=8.75×1017 exp(−10900/RT)(ΔC)2.8MT1.17, where B0 is the nucleation rate, ΔC is the supersaturation, and MT is the slurry density. The growth rate equation suggested was G = 5.72 × 1013 exp(−10400/RT)(ΔC)2.7, where G is the growth rate of adduct particles. Fitting model predictions to experimental data demanded no addition of agglomeration terms to population balance equation which suggests an insignificant mechanism of agglomeration in particle enlargement. The nucleation and growth rate equations obtained in this study may be used to enhance the product quality of BPA plants.