Microwave-assisted synthesis of solketal from glycerol and acetone

Abstract

Herein, microwave-assisted synthesis of solketal from glycerol and acetone in the presence of montmorillonite modified with aqueous solution of 0.25 mol/l HCl (0.25M HCl/MM) was demonstrated. The reaction was studied in a methanol solution at an acetone/glycerol molar ratio of 2.45–7.53, a catalyst concentration of 1.2–2.8 wt.% (based on the mass of loaded glycerol), and 30–56 °C. Solketal was shown to be the major product with 96.1–99.2 % selectivity. The maximum solketal yield of 91.3 % with 98.6 % selectivity was obtained in 15 min of the reaction at an acetone/glycerol molar ratio of 7.53, a catalyst loading of 2.3 wt.% and 56 °C. The catalytic properties of 0.25M HCl/MM in the reaction under MW heating and thermal conventional heating were compared. It was found that the yield of solketal in the MW-assisted synthesis is 2 times higher compared to the process with conventional heating.