Preparation, characterization and catalytic activity of MMT-clay exchanged sulphonic acid functionalized ionic liquid for transesterification of β-ketoesters

A novel solid acid catalyst 2 was prepared by ion exchange of sulphonic acid functionalized ionic liquid into clay interlayers as a new organic–inorganic hybrid catalytic system. The ionic tag of the imidazolium supported sulphonic acid 1 assists in the pillaring process and enhances the organophilicity of catalyst 2 in the interlayers of clay. The catalytic activity of catalyst 2 as a recyclable solid Bronsted acid has been tested for the chemoselective transesterification of ethyl/methyl β-ketoesters with various alcohols in good yields with high TON/TOF.