Catalytic synthesis of glycerol carbonate from biomass-based glycerol and dimethyl carbonate over Li-La2O3 catalysts

The trans-esterffication of glycerol and dimethyl carbonate (DMC) for the synthesis of glycerol carbonate was investigated over a series of Li-La2O3 catalysts with different Li contents under mild reaction conditions. Li-La2O3 catalysts were prepared by simple precipitation and impregnation methods, and characterized using ICP, XRD, BET, XPS, CO2-TPD and TEM techniques. It was found that the basicity of La2O3 was obviously changed and the interaction between Li and La2O3 occurred after doping Li component, and the catalytic activity of Li-La2O3 was highly relevant to the strength and content of basic sites on the catalysts. Li doping influenced the crystal phase growth of La2O3, and also changed the exposed crystal planes of the Li-La2O3 catalysts. The highest catalytic performance was obtained over 3.50Li-La2O3 catalyst calcined at 600 degrees C for 5 h. The glycerol conversion of 94.4% and glycerol carbonate selectivity of 92.1% were obtained over this catalyst under the proper reaction conditions of 85 degrees C, 3 h, and the molar ratio of glycerol and DMC being 1/3 with using 0.1 g 3.50Li-La2O3 catalyst.