Chitosan-modified Pd(II)-d-penicillamine: preparation, characterization, and catalyst application

A new derivative of chitosan was prepared via a chemical modification process which included chemical bonding of chitosan with d-penicillamine and anchoring of Pd(II) to the chitosan-d-penicillamine. Chitosan-modified Pd(II)-d-penicillamine was characterized by FT-IR, CHNS analysis, flame absorption atomic spectroscopy, energy dispersive X-ray spectroscopy, X-ray diffraction pattern and thermal gravimetric analysis. The importance of biopolymers in the catalytic transformation led us to use the synthesized compound as a catalyst in the oxidation reaction of benzyl alcohol to benzoic acid. High yield and excellent selectivity was achieved for the selective oxidation of benzyl alcohol in H₂O at room temperature using H₂O₂ as a green oxidant during 24 h. The reaction has some advantages such as green and mild reaction conditions, high yield, excellent selectivity, green oxidant and short reaction conditions. Also, the catalyst is a stable compound and the recovered catalyst is usable for 4 times without any significant decrease in the yield.