Catalytic studies of aminated MCM-41-tethered rhodium complexes for 1-hexene hydroformylation

Abstract

Rhodium complexes have been tethered to silicate MCM-41 via an amine ligand. X-ray diffraction (XRD) and N 2 adsorption–desorption studies illustrate that the resultant materials maintain the mesoporous structural ordering of MCM-41, but exhibit reduced pore sizes, total pore volumes and BET surface areas. Comparative catalytic studies have been performed of the aminated MCM-41-tethered rhodium complexes and the corresponding untethered rhodium complexes in 1-hexene hydroformylation at 80 °C and 195–1950 kPa (H 2/CO=1). The tethered PPh 3-free rhodium complex has disadvantage over the corresponding untethered one in catalytic activity and selectivity except for n/ i aldehyde ratio. The tethered PPh 3-containing rhodium complex has advantage over the corresponding untethered one in catalytic activity and selectivity except for n/ i aldehyde ratio. Excess PPh 3 added enhances obviously the performances of the tethered PPh 3-containing rhodium complex in all aspects. The effects of total reaction pressure and donor ligands on the catalytic properties are dealt with.