Rhodium Catalyzed Hydeoformylation of Ethylene

摘要

Hydroformylation of alkenes is an important chemical process, and usually uses homogeneous catalysts composed of rhodium, cobalt, and other transition metal complexes. Heterogeneous hydroformylation is a promising process from a practical point of view. It is also interesting to elucidate the mechanism of CO hydrogenation, because it involves common processes such as CO insertion, and uncommon process such as CO dissociation. We previously described highly selective catalysts to form oxygenated compounds by CO hydrogenation and hydroformylation of ethylene over cobalt catalysts, and found that high dispersion of cobalt is essential for the formation of oxygenated compounds (1-7). We also reported the effects of particle size and the modification of Rh/SiO_2 in the CO hydrogenation (8-11). In this paper, we examine two aspects of rhodium catalysts to clarify the mechanism of CO hydrogenation and the hydroformylation. One is the effect of particle size of rhodium in the hydroformylation of ethylene, and the other is the effect of the modification of Rh/SiO_2 on the reaction. C_2H_4 + CO + H_2 -> C_2H_5CHO + C_2H_6 1)