Impact of supported ionic liquids on supported Pt catalysts

Abstract

Silica supported platinum catalysts coated with a thin film of 1-butyl-2,3-dimethyl-imidazolium trifluoromethane sulfonate (BDiMIm) were investigated with respect to the interaction of the ionic liquid with the oxide support and the metal clusters. IR, inelastic neutron scattering and NMR spectroscopy indicate that the vibrations of the imidazolium ring of ionic liquid are less restricted when supported on SiO₂, while the viscosity of the supported ionic liquid increased. The presence of Pt particles enhances the electron density of the ionic liquid at the nitrogen atom inducing higher basicity. The coverage of the catalyst surface and the metal particles by the ionic liquid protects the metal against oxidation. The catalysts are active and stable for hydrogenation of ethene.