Intensification of isoamyl acetate production: transport properties of silica membranes

Fuel ethanol production by fermentation generates isoamyl alcohol as by-product. Its conversion to isoamyl acetate is an alternative to obtain a higher value product. An intensified reaction–pervaporation process is an attractive option compared to conventional distillation. The design of this process requires the characterization of the transport properties of the membrane used. Xerogel type ceramic membranes were prepared by dip-coating and analyzed by using Brunauer-Emmett-Teller method, fourier transform infrared spectroscopy, and scanning electron microscopy–energy dispersive spectrometer methods. Their hydrophilic and microporous character was confirmed. Using quaternary mixtures of the esterification process, a membrane was evaluated for water separation in a laboratory scale pervaporation unit. A special experimental protocol for membrane evaluation was proposed for the multicomponent reactive mixture. Experimental membrane flux and selectivity were determined and used to correlate three basic mass transport models. Among them, the most suitable and reliable was the thermodynamic Fick model, which can be used for reaction-pervaporation process design and simulation.