Catalytic hydrogenation of cyclohexene: liquid-phase reaction on rhodium

Abstract

The turnover rate v_t for the liquid-phase hydrogenation of cyclohexene on Al₂O₃-supported clusters of rhodium containing ca. 12 atoms was found to be the same as that on supported rhodium clusters containing 150 atoms or more. The smallest rhodium clusters were examined by chemisorption of H₂ and CO, by infrared spectroscopy of adsorbed CO, and by extended X-ray absorption fine structure, which indicated an average coordination number of five for the first shell. The results show that ligand effects for metallic clusters containing only a few atoms have no observable effect on the measured rate of the structure-insensitive reaction under study.