Design, Preparation, and Characterization of a Novel IL-Based Catalyst, [(Et3N)2SO][HSO4]2, as an Efficient and Recyclable Catalyst in Biginelli Reaction under Solvent-Free Conditions

Abstract

A novel dicationic Brönsted acidic ionic liquid, [(Et3N)2SO][HSO4]2, was prepared and characterized using FT-IR, 1H NMR, 13C NMR, and MS and evaluated as a catalyst in the Biginelli reaction. The advantages of this method include novelty in terms of the ionic liquid, together with high efficiency, easy workup procedure and purification, convenient operation, and environmentally benign reaction conditions. Also, the catalyst can be easily separated from the reaction mixture and reused in five consecutive cycles without significant loss in catalytic activity.