Promoting effect of Al on tethered ligand-modified Rh/SiO2 catalysts for ethylene hydroformylation

• A new catalyst was prepared by doping Al to a tethered phosphine modified Rh/SiO2.
• The activity of the catalyst was increased about 4-fold after Al doping.
• Al enhances the number of exposed Rh atoms and the amount of active species.
• Al changes the acidity of the surface and interacts with the tethered phosphine.

A Rh/SiO2 catalyst with excellent activity and stability for ethylene hydroformylation was developed by modifying with tethered diphenylphosphinopropyl and doped with an Al promoter. The catalyst was characterized by means of N2 adsorption/desorption isotherms, transmission electron microscope, NH3 temperature programmed desorption, Fourier transform infrared spectroscopy and solid-state nuclear magnetic resonance. Experimental results showed that the existence of the Al promoter inhibited the growth of Rh particles, increased the number of exposed Rh atoms, changed the acidity of the catalyst surface, promoted in situ formation of active species that were similar to their corresponding homogeneous counterparts, and enhanced electron density of the P atom in the phosphine ligand.

Figure optionsDownload high-quality image (174 K)Download as PowerPoint slide