Enhancement of esterification conversion using novel composite catalytically active pervaporation membranes

A catalytically active pervaporation membrane with a novel composite structure has been prepared by using the immersion phase inversion method. SEM images show its structure containing three layers: the top layer is a porous catalytic layer, the middle layer is the dense PVA selective layer and the bottom layer is the commercially available PES support layer. Esterification reaction of acetic acid and n-butanol is used as a model reaction to test its performance. Batch reaction results show that its catalytic activity is comparable to that of catalyst beads. The result of esterification reactions in pervaporation membrane reactors (PVMRs) shows that the acetic acid conversion reaches 91.4% in 20 h at 85 °C by using the catalytically active membrane, while the equilibrium conversion is around 71.9% under the same condition. The increase of temperature also facilitates the enhancement of acetic acid conversion. The catalytic activity and structure stability of the catalytically active membrane are further confirmed by consecutive experiments and SEM analyses.