EXAFS Characterization of Pd Catalysts for Enantioselective Hydrogenation of α-Phenylcinnamic Acid: Pretreatment Effects and Thiol Adsorption

The effects of the pretreatment and Pd-distribution on the enantioselective hydrogenation of α-phenylcinnamic acid over cinchonidine-modified Pd/C and Pd/Al2O3 were studied by use of EXAFS techniques combined with thiol adsorption. It is suggested that the enhanced performance by the H2-pretreatment at 353 K is ascribed to the elimination of contaminants and/or H2O from Pd/C. The Pd–S CN is related to the Pd dispersion and the reactivity and diffusivity of thiols used.