Pd doped Co functionalized SBA-15 as an active magnetic catalyst for low temperature solventless additive-base-free selective oxidation of benzyl alcohol

Benzaldehyde as an important and versatile platform chemical for fine chemicals has been successfully synthesized via selective oxidation of benzyl alcohol using palladium doped cobalt-oxide based silica catalyst (Pd/CoMagSBA) prepared by a solvent-less ball-milling process. The developed catalysts demonstrate excellent reactant conversion and product selectivity (∼83.2 %) in solvent-less, additive-base-free and mild reaction conditions (70−90 °C, atmospheric pressure) as well as can be easily recycled by magnetic separation without any regeneration. Different Pd loading percentages, magnetic metal loading (cobalt oxide loading) percentages, and reaction temperatures have been investigated for optimization of efficient catalysis. The catalytic efficiency of Pd nanoparticles and the unique promotional synergism of Co nanoparticles drive the reaction efficiency of the benzaldehyde formation. The stable activity of the recovered catalysts has been observed in the repeated reaction runs. Parallel experiments have been conducted using different metallic catalysts (Pd/MnSBA, Pd/CuSBA and Pd/ZnSBA) to investigate the role of chemical configurations of the palladium and cobalt and their catalytic roles.