Preparation Of Supported Ionic Liquid And Its Application In Catalytic Reaction

In recent years,supported ionic liquids have been central to many areas of chemistry.The supported ionic liquid material retains the unique physicochemical properties of the ionic liquid.At the same time,it also overcomes many of negative aspects of conventional ionic liquid,such as leaching,poor recovery and so on.They have been used as functional materials for supports of catalysts,stationary phases in separation technologies and electrodes in electrochemistry.A novel palladium immobilized on reduced graphene oxide(RGO)heterogeneous catalyst was prepared.The reduced graphene oxide was functionalized by an imidazolium-based ionic liquids containing polyethylene glycol monomethyl ether moieties.Characterization of the heterogeneous catalyst using X-ray photoelectron spectroscopy(XPS),thermogravimetric analyses(TGA),inductively coupled plasma mass spectrometry(ICP-MS)and transmission electron microscopy(TEM)confirmed the well-defined nature of the hybrid catalysts.The presence of a homogeneous distribution of palladium nanoparticles was established.The prepared catalyst was applied to the Suzuki-Miyaura coupling reaction of aryl bromide and phenylboronic acid,and its catalytic activity was investigated.These catalysts were proved to be efficient in Suzuki-Miyaura coupling reaction with green solvent at room temperature and the substrate scope was wide.TEM analysis of the catalyst,which was after the five run,confirmed that the palladium nanoparticles remained monodisperse mostly with a bigger diameter.XPS spectrum of catalyst after recovery was similar with the spectrum of fresh catalyst,even most of Pd? was reduced to metallic Pd.The catalyst exhibited good reusability and could be reused for five times without significant decrease in catalytic activity.The catalyst was also used to the hydrosilylation of phenylacetylene.The effects of the amount and type of supported ionic liquid palladium catalyst,silane reagents,additives and solvents on the reaction were investigated.The optimized conditions for the reaction proved to be the prepared Pd catalyst(Pd:0.05 mol%),Nal in MeCN at room temperature.The catalyst also exhibits good catalytic activity,selectivity and reusability with mild reaction condition and wide substrate range.