Liquid Catalysts Supported through Physisorption or via Electrostatic Interaction

4 Ionic Liquid Catalysts Supported through Physisorption or via Electrostatic Interaction 

A second and somewhat simpler approach that can be applied to obtain supported ionic liquid catalyst systems involves the treatment of a solid, porous carrier material by a substantial amount of a catalytically active ionic liquid, allowing the reaction to take place in the dispersed phase. In these systems the ionic liquid phase can itself act as the catalytically active component or it may contain other dissolved compounds or reagents, for example, transition metal complexes, which function as the catalytically active species (i.e. generating SILP catalysts). Importantly, the ionic liquid catalyst phase in these SILP catalyst systems are confined to the carrier surface only by weak van der Waals interactions and capillary forces interacting in the pores of the support. In special cases electrostatic attachment of the ionic liquid phase may also be applied. Usually, the catalysts are prepared by traditional impregnation techniques, where a volatile solvent is used initially to reduce viscosity for the impregnation process and is finally removed by evaporation leaving the ionic catalyst solution dispersed on the support. 

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