PVA composite catalytic membranes for hyacinth flavour synthesis in a pervaporation membrane reactor

• Acetalization of glycerol and phenylacetaldehyde catalyzed by PVA/H-USY composite membranes.
• Effects of catalyst loading, polymer cross-linking and polymer acetylation on the membranes’ transport properties.
• Fitting of a diffusion-kinetic model to kinetic data assuming dependence of phenylacetaldehyde diffusivity on products concentration.
• Performance of a pervaporation assisted polymeric catalytic membrane reactor.

Composite catalytic membranes consisting of poly(vinyl alcohol) cross-linked with glutaraldehyde and H-USY zeolite dispersed into the polymeric matrix were prepared and used in the hyacinth flavour synthesis by acetalization of phenylacetaldehyde and glycerol.In order to study the effects of catalyst loading, polymer cross-linking and hydrophilic/hydrophobic balance in the catalytic behaviour of the prepared membranes, catalytic runs were performed in batch conditions and in a pervaparation assisted catalytic membrane reactor. It was found that polymer cross-linking strongly affects the membranes’ sorption and transport properties which seem to improve with the increase of catalyst loading. Results also evidence that permeation in membrane reactor was well accomplished with good selectivity to water.The catalytic membranes were characterized by measurement of thickness, water contact angles and swelling degree as well as by Fourier transform infrared spectroscopy (FTIR), atomic force microscopy (AFM) and scanning electron microscopy (SEM).

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