Ionic liquid coated sulfonated carbon/silica composites: novel heterogeneous catalysts for organic syntheses in water

Abstract

Ionic liquid coated sulfonic acid functionalized amorphous carbon/silica composites derived from a starch–glucose mixture were developed and their catalytic activities were evaluated for Knoevenagel condensation, reductive amination of aldehydes and ketones, and for Michael addition of indole to α,β-unsaturated ketones in aqueous medium. The catalyst prepared from starch–glucose mixture (3 : 1) [CSC-Star-Glu-IL2] showed the highest activity in water. The catalysts were characterized by FTIR, TGA, elemental analysis, and the most active was further characterized by XRD, SEM and TEM.