Synthesis of Pd/XC-72 catalysts by a facile glutamate-mediated method for solvent-free selective oxidation of dl-sec-phenethylalcohol

Abstract

Nanoscale palladium (Pd) catalysts supported on XC-72 using a facile one-pot method with glutamate as an additive were synthesized. We found that small Pd nanoparticles with the average size of 3.2 nm dispersed on the surface of XC-72 were prepared through the addition of a certain amount of glutamate into the precursor solution. As a comparison, Pd/XC-72 catalysts were prepared using the formaldehyde reduction method and impregnation method respectively. The catalytic activities of these catalysts for solvent-free oxidation of DL-sec-phenethylalcohol with molecular oxygen were also studied. The catalytic activity of Pd/XC-72 by the glutamate-mediated method was the highest, and the DL-sec-phenethylalcohol conversion was ca. 99% at 403 K in 5 h. The characterization of TEM, XRD, FT-IR, and TGA suggested that the glutamate-mediated method resulted in small Pd nanoparticles size and small amounts of residual glutamate, and thus enhanced the oxidation of alcohols.