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

Abstract

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 N₂ 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 °C.