Heterogeneous synthesis of glycerol carbonate from glycerol and dimethyl carbonate catalyzed by LiCl/CaO

In this article, a CaO-based catalyst was prepared by impregnating chloride salts on CaO to develop a highly efficient heterogeneous catalyst for the synthesis of glycerol carbonate (GC) from glycerol and dimethyl carbonate. LiCl/CaO exhibited a high catalytic activity under moderate reaction conditions. The effects of the LiCl loadings, the amount of catalyst and the calcination temperature on the catalytic activity were investigated. The highest yield of 94.19% glycerol carbonate was obtained at 65 °C on CaO loaded with 10% LiCl after 1 h, and the catalyst had high stability in reusing work. Scanning electron microscopy (SEM), X-ray diffraction (XRD), BET, CO₂-TPD, XPS and thermalgravity (TG) were used to characterize the prepared catalyst. It was found that the high catalytic activity of CaO after modification with LiCl is associated with the structural aspects and the amount of basicity of the catalyst. The Li₂O₂ species, which is a strong basic site that is formed by the substitution of the Ca²⁺ in CaO lattice by Li⁺, has great activity for transesterification.