CaO-catalyzed synthesis of glycerol carbonate from glycerol and dimethyl carbonate: Isolation and characterization of an active Ca species

[Display omitted] ► CaO-catalyzed transesterification of DMC by glycerol was found to proceed in a homogeneous way when the molar ratio of DMC/glycerol less than 2. ► At the molar ratio of DMC/glycerol higher than 2, there is a considerable contribution of heterogenous catalyst. ► An active species was isolated from the reaction mixture and characterized as Ca(C 3H 7O 3)(OCO 2CH 3). The transesterification of dimethyl carbonate (DMC) with glycerol to produce glycerol carbonate was investigated in the presence of CaO under various reaction conditions. CaO was completely dissolved in the reaction mixture of glycerol and DMC in 5 min at 75 °C and at the molar ratio of glycerol/DMC/CaO of 1/2/0.01. The isolation and the characterization of the dissolved Ca species by means of TOF-SIMS, elemental analysis, and FT-IR revealed that an active species, Ca(C 3H 7O 3)(OCO 2CH 3) is generated from the interaction of CaO with glycerol and DMC. The mechanistic pathways to the formations of Ca(C 3H 7O 3)(OCO 2CH 3) and glycerol carbonate are discussed on the basis of experimental and spectroscopic results.