Efficient Oxidation of Benzyl Alcohol to Benzaldehyde with Hydrogen Peroxide Mediated by Palladium Chloride Impregnated on Aluminium Oxide-Pillared Clay

Abstract

Aldehydes, such as benzaldehyde, are very important in many industries and can be prepared from alcohols. In this research, aluminium oxide-pillared bentonite (Al-PILC) was prepared by inserting aluminium (III) chloride into the interlayers and calcination. Then PdCl₂ was impregnated into Al-PILC and calcined to produce Pd/Al-PILC. The synthesized clay and raw clay were characterized by X-ray diffraction (XRD) and N₂ adsorption-desorption (Brunauer-Emmett-Teller; BET) techniques. From the characterization, XRD pattern exhibited the characteristic peaks of montmorillonite at 2θ of 7° and 22°. Additionally, the N₂ adsorption-desorption isotherm of Pd/Al-PILC indicated mesoporous structure and BET specific surface area was 102 m²/g. The catalytic activity of Pd/Al-PILC was investigated for the oxidation of benzyl alcohol with H₂O₂ furnishing benzaldehyde. In the optimum condition, 82% of benzaldehyde was produced via the reaction of benzyl alcohol and H₂O₂ in the presence of a catalytic amount of Pd/Al-PILC in refluxing acetonitrile for 3 h under mild reaction conditions.