A Waste-derived Lithium Metasilicate Basic Catalyst

Abstract

A mixed product of lithium metasilicate (74%) and minor proportions of calcium carbonate, lithium carbonate and calcium hydroxide was prepared by hydrothermal synthesis from waste green container glass in 4 M lithium hydroxide solution at 125 °C. The reaction product was characterised by powder X-ray diffraction and Fourier transform infrared spectroscopy. The lithium metasilicate product was found to be a successful heterogeneous catalyst for the Knoevenagel synthesis of ethyl trans-α-cyanocinnamate from benzaldehyde and ethyl cyanoacetate.