Aerobic oxidation of benzyl alcohol: Influence from catalysts basicity, acidity, and preparation methods

Abstract

The effect of catalyst preparation method and metal precursors on the catalyst basicity were studied in Pd catalysts supported on magnetic SBA-15 for benzyl alcohol oxidation (BzOH) to benzaldehyde (BzH). The reaction was carried out in an environmentally friendly condition, i.e, in the absence of additive and solvent, at low temperature (95 °C) in the presence of oxygen. Various techniques such as ball milling and impregnation as well as different precursors such as nitrate and chloride of palladium were applied for catalyst preparation. Among them, MPM-2 catalyst which was prepared by nitrate precursor and physical hand mixing, exhibited the most optimized basicity. The intensity of 2.9 × 10−10 of total basicity was measured by CO2-TPD experiment. The catalysts showed 50 % of BzOH conversion and 95 % of selectivity towards BzH after 3.5 h. The activation energy of the reaction was significantly decreased and reached 17.6 kJ.mol-1.