Effect of Preparation Method on the Catalytic Property of Calcined Ca-Al Hydrotalcite for the Synthesis of Ethyl Methyl Carbonate

Calcined Ca-Al hydrotalcites were prepared by a clean method (CaAl-1) and coprecipitation (CaAl-2), respectively. Effects of preparation methods on the structure and catalytic property of calcined Ca-Al hydrotalcites were investigated. The samples were characterized by X-ray diffraction (XRD), inductively coupled plasma optical emission spectroscopy (ICP-AES), X-ray photoelectron spectroscopy (XPS), thermogravimetric (TG), CO2-programmed temperature desorption method (CO2-TPD), low-temperature N-2 adsorption-desorption, and the Hammett indicator method. Compared with CaAl-2, CaAl-1 had a higher specific surface area and surface alkali density, which makes it have relatively higher catalytic activity for transesterification synthesis of ethyl methyl carbonate (EMC). Also, a 50.6% yield of EMC was obtained in the presence of 1.5% CaAl-1 at 100 degrees C in 1 h. Moreover, the catalytic activity of CaAl-1 showed no remarkable change after five runs.