“…In recent years, ionic liquids (ILs) have attracted extensive research interest as clean catalysts and excellent solvents due to their unique physical and chemical properties, such as negligible vapour pressure, remarkable solubility, high thermal stability and effortless reusability. [8][9][10][11][12] Till now, some acidic ionic liquids have been successfully used in esterication, [13][14][15] alkylation, [16][17][18] acetalization, 19,20 ketalization, 21 hydration, 22,23 etc., which have showed high catalytic activity and selectivity. In 2001, Deng et al reported their early work on the acetalization and ketalization using acidic chloroaluminate ILs as catalyst with high conversion and selectivity.…”