Transesterification processes by combination of reactive distillation and pervaporation

The development of a reactive distillation process for the production of n-butyl acetate by transesterification of methyl acetate with n-butanol is presented. Thermodynamic aspects of the quaternary system n-butyl acetate–n-butanol–methyl acetate–methanol are discussed and UNIQUAC interaction parameters derived using the Dortmund Data Bank (DDB) are given. The reaction kinetics of the heterogeneously by a strongly acidic ion-exchange resin (Amberlyst 15) catalyzed reaction has been investigated and the kinetic constants for a pseudohomogeneous kinetic model are presented. Pervaporation experiments using Pervap 2255 membranes have been conducted for the separation of the methanol–methyl acetate binary mixture which forms the distillate stream of the reactive distillation column. Reactive distillation experiments have been performed using the structured catalytic packings Katapak-S (Sulzer Chemtech) and Katapak-SP (type SP 11, Sulzer Chemtech). Important operating conditions (reflux ratio, total feed rate) have been varied experimentally. The experimental results are presented in comparison with simulation results. An equilibrium stage model for the modeling of the distillation is capable of describing the composition profiles quantitatively. Finally, a new process, combining reactive distillation with pervaporation, has been developed and investigated by means of simulation studies. It has been shown that the combination of reactive distillation with pervaporation is favorable since conversions close to 100% can be obtained with a reasonable size of the reactive section.