The synthesis of glycerol carbonate from glycerol and CO2 over La2O2CO3-ZnO catalysts

The transformation of CO2 and glycerol into glycerol carbonate was carried out by using acetonitrile as coupling agent over La2O2CO3-ZnO in the present work. A series of La-Zn mixed oxide catalysts with different molar ratios were prepared and calcined at different temperatures. The catalysts were characterized by N-2 physisorption, XRD, XPS, FT-infrared spectroscopy and temperature-programmed desorption of CO2. The results revealed that the formation of La2O2CO3 improved the surface basicity which then favors the CO2 activation and the carbonate yield was shown to be correlated with the amount of moderately basic sites. The XPS measurement demonstrated that La2O2CO3 favored the electron transfer from zinc atoms to lanthanum atoms or oxygen atoms which then favors the activation of glycerol. The synergism between ZnO and La2O2CO3 is responsible for the high catalytic activities of the La-Zn catalysts. The best result was obtained on the catalyst with molar ratio of La : Zn = 1 : 4 and calcination at 500 degrees C.