New efficient and recyclable catalysts for the synthesis of di- and tri-glycerol carbonates

Multifunctional monomers based on glycerol carbonate are employed in the chemical industry for the production of polyurethanes and polycarbonates. To avoid the use of toxic phosgene as carboxylating reagent, eco-friendly routes have been developed using alternative agents. In this paper, a series of binary and ternary oxides have been tested as catalysts in the synthesis of diglycerolether dicarbonate (DGDC) and diglycerol tricarbonate (DGTC) using dimethyl carbonate (DMC) and urea as carboxylating agents. The recovery and reuse of the catalysts are discussed. In the best reaction conditions, using mixed oxides La:Ca = 1:1 as catalysts, the yields of DGDC and DGTC were >90 (pure isolated compounds) and 19.9%, respectively.