Interactions of rhodium carbonyl compounds supported on inorganic oxides with CO, H2 and propylene

Abstract

RhCl(CO)(PPh3)2, RhH(CO)(PPh3)3, and [RhClfCO)2]2 were supported on silica gel, γ-alumina, titania.and magensia in 3 to 5 wt % to study the interactions of rhodium carbonyl with the surface of inorganic oxides When trans-RhCI(CO)(PPh3)2 was supported on the surface of silica gel, cis-RhCl(CO) (PPh3)2 species was detected via the splitting of the CO infra red stretching band of trans-RhCI (CO)(PPh3)2. With other supports, same phenomenon was observed but with the different pattern of intensities of the splitted CO stretching bands. RhH(CO)(PPh3)3 was easily decarbonylated, after interacting with the surface of silica gel, γ-alumina, and titania. However, [RhCl(CO)2]2 was decarbonylated on the surface of inorganic oxides mentioned above and most of supported [RhCl(CO)2]2 converted to a stable surface carbonyl species [M-OH-RhCI(CO)2; M = Si, Al, Ti]. Diffuse reflectance infrared spectroscopy (DRS) was used to study the interactions of 5 wt % RhCl(CO)(PPh3)2 supported on silica gel with H2, CO and/or propylene at various temperatures. The result indicated that the surface intermediates formed from the interaction of RhCl(CO)(PPh3)2 with CO, H2 and C3H6 were not identical to the corresponding liquid-phase intermediates of RhCl(CO)(PPh3)2 in the presence of solvent. © 1987 Korean Institute of Chemical Engineering.