Partial hydrogenation reactions over Pd-containing hybrid inorganic / polymeric catalytic membranes

Palladium nanoparticles (4.6 nm) were grown into a hybrid zirconia / polyvinyl alcohol matrix, to afford a contactor type catalytic membrane suitable for application to partial hydrogenation reactions in the liquid phase under smooth conditions. A Pd content as low as 0.3% weight allowed for the hydrogenation of C=C and C?C bonds within reasonable timeframes and satisfactory selectivity. Particularly, the partial hydrogenation reaction of 3-hexyn-1-ol to the cis-ene product could be achieved with no significant loss of catalytic performance over prolonged reaction period. The catalytic system showed significant benefits in terms of metal leaching, efficiency under mild reaction conditions, reusability, mechanical and chemical stability, use in hydrophilic solvents, with no need of regeneration steps.