Green synthesis of glycerol carbonate using efficient mixed oxide catalysts

Abstract

The transcarbonation reaction of glycerol (Gly) with diethyl carbonate (DEC) was investigated to synthetise glycerol carbonate (GC) using two major types of basic catalysts: conventional carbonates (K2CO3 and Na2CO3) and, for the first time in this context, metal oxides (CaO, MgO, MgO/CaO and KNO3/CaO) calcined at 700 or 900 °C. The introduction of metal oxides as catalysts represents a novel approach for this type of transcarbonation reaction. Analyses showed that the mixed CaO based metal oxides have a porous structure suitable for the transcarbonatation reaction and higher BET surface areas compared to single CaO oxide. Two different loadings of each catalyst (5 and 10% mass related to Gly) were used with 2:1 molar excess of DEC to produce GC during 3 hours at 110 °C under mechanical stirring (500 rpm). The results showed the interest of using mixed oxides (MgO/CaO or KNO3/CaO) calcined at the appropriate temperature, to obtain GC yields and selectivity higher than 90% without byproducts formation.