Hydrogenation of benzaldehyde over palladium intercalated bentonite catalysts: Kinetic studies

Bentonite, a 2:1 type swellable phyllosilicate clay mineral having exchangeable inorganic cations in the interlamellar space to nullify their charge deficiency was used to generate palladium nanoparticles. It was found that 1% w/w palladium nanoparticles were generated in the interlamellar space using adsorption excess technique. The synthesized catalysts were characterized by using XRD, TEM, BET surface area analysis, and AAS. The modified clay catalysts were tested for their catalytic activity towards the hydrogenation of benzaldehyde to benzyl alcohol in liquid phase using a high-pressure reactor at various temperatures and pressures. High selectivity (100%) towards the desired product of benzyl alcohol was achieved with conversion over 80% in all cases. These results showed different hydrogen dependency for the reaction at various temperatures. The kinetics of the reaction was studied using Langmuir Hinshelwood single site model. The rate constant was determined using pseudo first-order kinetics and activation energy for benzaldehyde hydrogenation was calculated at various temperatures using Arrhenius equation and was found to decrease with increase in temperature.