Synthetic nano-clays to be used in the valorization of glycerol to glycerol carbonate

Abstract

Biodiesel production is accompanied by 10 wt.% of glycerol as a by-product. Thus, the use of glycerol as a renewable raw material could be an economical advantage to the process. The catalytic conversion of glycerol to a higher value-added product such as glyceryl carbonate is an attractive option. Glyceryl carbonate is considered a green substitute for important petroleum-derived compounds. In addition, it has numerous applications in the chemical, pharmaceutical and cosmetic industries. The transesterification reaction between glycerol and an alkyl carbonate is a sustainable alternative when solid catalysts such as mixed metal oxides derived from synthetic anionic nano-clays are evaluated, along with under mild reaction conditions and without solvent employment. The great interest in the use of these materials is due to the possibility of custom nano-design, accessibility control to active sites and very low cost synthesis. The Mg and Al oxides with Cu incorporated in different loads were synthesized by the coprecipitation method. The materials were characterized physicochemically by TPD-CO2, FTIR and XPS and evaluated in the reaction between glycerol and ethylene. All samples with Cu incorporated showed significant activity to selective glyceryl carbonate production. Those catalytic performances could be attributed to the strong basicity on the surface combined with the acid sites presence of the materials. The most active catalyst was oxide with 25% Cu content with 91.9% glycerol conversion and 99.2% selectivity to glyceryl carbonate.