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A better conversion enhancement of esterification between acetic acid and n-butanol was achieved in a catalytically active membrane reactor ( p CAMR) when compared to that in a traditional inert membrane reactor (IMR). This enhancement was attributed to a novel composite catalytically active membrane in which a highly porous catalytic layer was introduced. SEM images showed that the membrane consisted of three layers: the top layer was a highly porous catalytic layer with massive macrovoids and “sponge-like” pores, the middle layer was a dense polyvinyl alcohol selective layer, and the bottom layer was a porous polyethersulfone support layer. The preparation of a highly porous catalytic layer instead of a dense one in the composite membrane greatly decreased the overall mass transfer resistance of the reactor from 6.7 × 10 5 to 5.6 × 10 5 s/m, a value which is even comparable to that of IMR (5.1 × 10 5 s/m) where the additional catalytic layer was absent. The effects of operational parameters on the esterification-pervaporation coupling performance in p CAMR were systematically evaluated. Through a reasonable match between reaction rate and water removal rate, a genuine in-situ water removal at a molecular lever was realized. For comparison, coupling performances in an IMR and a catalytically active membrane reactor with a dense composite membrane ( d CAMR) were also investigated. Results showed that the coupling performance in p CAMR outperformed both IMR and d CAMR due to a combination of much lower overall mass transfer resistance and higher mass transfer driving force for water removal in p CAMR. After 45 h at 85 °C, the acid conversion in p CAMR reached almost completion, an approximately 43% of conversion enhancement was achieved when compared to equilibrium conversion. [ABSTRACT FROM AUTHOR]

Glycerol ketals are often considered as important bio-based diesel additives or perfume substances which could be synthesized from the acetalization of glycerol and cyclohexanone, however, acetalization is a typical example of reactions controlled by thermodynamic equilibrium. In this study, a catalytically active membrane was prepared by immersion phase inversion and was used for the conversion enhancement of present reaction by continuous removal of by-product water in a pervaporation membrane reactor. SEM images showed that a highly porous “sponge-like” catalytic layer immobilized with catalyst Zr(SO 4 ) 2 ·4H 2 O was uniformly coated on a polyvinyl alcohol/polyethersulfone pervaporation membrane. Synthesis performances in batch reactor, inert membrane reactor and catalytically active membrane reactor were compared, showing that no equilibrium limitation for glycerol conversion was observed in both the inert membrane reactor and catalytically active membrane reactor. The effect of various operational parameters on the synthesis performance in the catalytically active membrane reactor were investigated, showing that higher temperature and A/V ratio favored better enhancement in glycerol conversion since an acceleration of water removal rate was induced. Optimal catalyst loading and initial mole ratio was also determined for better synthesis performance. Under optimized conditions, the glycerol conversion reached 93% and a conversion enhancement of approximately 52% was achieved when compared to equilibrium conversion at 75 °C. [ABSTRACT FROM AUTHOR]