A reusable and highly active heterogeneous catalyst of the type Mg1+xCa1-xO2 has been developed and thermally treated at 850 degrees C for 6h. The catalytic activity was investigated during the transesterification of glycerol with dimethyl carbonate to synthesize the valuable glycerol carbonate. A typical Mg1,2Ca0.8O2 mixed oxides catalyst was characterized by BET surface area, surface base amount, CO2-TPD, XRD and FTIR, and its microstructure was studied by the aid of scanning and transmission electron microscopy. The investigated characteristics gave a clear insight into the catalytic performance of the catalyst. Over 0.30g of this catalyst, glycerol conversion was almost complete and the yield of glycerol carbonate was 100% under atmospheric pressure. The best reaction conditions are: molar ratio of glycerol/DMC of 1:2, reaction temperature of 70 degrees C and 90 min of reaction time. The transesterification results showed that the synergism interaction between Ca and Mg species in the catalyst structure was the reason for its high activity. (C) 2013 Elsevier B.V. All rights reserved.