Ionic liquid catalyzed solvent-free synthesis of chalcone and its derivatives under mild conditions

An ionic liquid (IL) catalyzed solvent-free process was developed for the direct synthesis of chalcone and its derivatives by using substituted acetophenones and benzaldehydes via aldol reaction under mild conditions. A series of acidic and basic ILs were selected and screened. The influences of cations and reaction conditions on product yield and selectivity were systematically investigated. The [Bmim]OH was identified as the optimal IL, with the highest yield and selectivity reaching up to 96.7% and 100%, respectively. A reaction mechanism-based kinetic model was established and regressed with experimental data, revealing the β -Hydroxylketone dehydrolysis with activation barrier of 37.8 kJ·mol −1 was observed as the rate-controlling step.