Highly active zinc oxide-supported lithium oxide catalyst for solvent-free Knoevenagel condensation

Li2O/ZnO catalyst was prepared by wet impregnation method and characterized by XRD, SEM, EDX, FTIR, BET surface area and UV-Vis diffuse reflectance spectroscopy. This study revealed a decrease in average particle size and change in the shape of the particles when Li2O was supported on ZnO. The activity of ZnO-supported lithium oxide catalyst was tested for Knoevenagel condensation of a variety of aromatic aldehydes with malononitrile and ethyl cyanoacetate at room temperature under solvent-free condition. The reaction was completed in a very short time with yields above 90% and the catalyst presented excellent reusability without any loss in the activity. Novel lithium oxide supported on zinc oxide catalyst was synthesized and analysed using several techniques. Lithium doping decreases the particle size, and band gap energy and increases the surface area and basic properties of the catalyst. The olefin derivatives were obtained in a very short reaction time under the solvent free condition at room temperature in a green protocol.