Silica Gel Supported Dual Acidic Ionic Liquid as a Recyclable and Efficient Catalyst for Esterification and Acetalization Reactions

A supported dual acidic ionic liquid was prepared via anchoring 3-sulfobutyl-1-(3-propyltriethoxysilane) imidazolium hydrogen sulfate onto common silica gel by covalent bond. The novel immobilized acidic ionic liquid illustrated high catalytic activity in esterification and acetalization reactions. The products could be separated by simple decantation and the recovered catalyst could be recycled without remarkable loss of catalytic activity even after eight runs for esterification and six runs for acetalization.