Cascade Synthesis of Glycidol via Glycerol Transesterification With Dimethyl Carbonate Over Mixed Metal Oxide

ABSTRACT The present study reports the development and application of a mixed metal oxide catalyst comprising Sr:Cu:Al in a molar ratio of 2:4:4 for the one‐pot synthesis of glycidol (GD), along with a process for its subsequent separation. A series of alkali and alkaline earth metals (Na, Mg, Ca, Sr, Ba, Cs, and Rb), were incorporated into Cu─Al catalysts via the coprecipitation method to evaluate their catalytic performance in the one‐pot GD synthesis. The synthesized catalysts were characterized using Brunauer–Emmett–Teller (BET) surface area analysis, x‐ray diffraction (XRD), x‐ray photoelectron spectroscopy (XPS), field emission scanning electron microscopy (FESEM), high‐resolution transmission electron microscopy (HR‐TEM), and Fourier‐transform infrared spectroscopy (FTIR). Among the evaluated catalysts, the Sr─Cu─Al (2:4:4) mixed oxide catalyst demonstrated optimal activity, achieving 66% selective GD formation with 78% glycerol conversion. Optimized reaction conditions for selective GD formation involved the use of Sr‐doped Cu–Al (2‐4‐4) catalyst at 140 °C, with a reaction time of “One‐step synthesis of glycidol from glycerol in gas‐phase fixed‐bed continuous flow reactor over alkali metal promoted aluminosilicate zeolite catalyst” 90 min and a catalyst loading of 100 mg. The formation of by‐products, including GDcarbonate, glycerol mono‐carbonate, and glycerol tri‐carbonate, was attributed to the presence of pendent hydroxyl groups and was confirmed through GC–MS. GD was successfully isolated from the reaction mixture by vacuum distillation.