Use of Microwave Irradiation to Synthesize Solketal from Glycerol and Acetone

It has been shown that solketal can be synthesized from glycerol and acetone irradiation in the presence of montmorillonite (MM) modified with an aqueous solution of 0.25 mol/L of HCl (0.25M HCl/MM). The reaction has been 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 glycerol weight), and 30–56°C. It has been shown that solketal is the major product with a selectivity of 96.1–99.2%. The maximum solketal yield of 91.3% with a 98.6% selectivity is obtained within 15 min of reaction at an acetone/glycerol molar ratio of 7.53, a catalyst loading of 2.3 wt % (based on glycerol weight), and 56°C. The catalytic properties of 0.25M HCl/MM in the reaction under microwave and thermal heating conditions have been compared. It has been shown that the solketal yield in the reaction under MW irradiation is 2 times higher than that in the process with thermal heating.