Glycerol acetalization over highly ordered mesoporous molybdenum dioxide: Excellent catalytic performance, recyclability and water-tolerance

Highly ordered mesoporous molybdenum dioxide (meso-MoO₂) was successfully synthesized by a nano-replication method using a mesoporous silica template with 3D cubic Ia3d mesostructure. Structural analyses using X-ray diffraction, N₂ sorption, and electron microscopy indicated that the meso-MoO₂ material exhibited high surface area (106 m²/g), large pore volume (0.66 cm³/g), and well-defined mesopores. Under the optimized reaction conditions, the meso-MoO₂ catalyst showed excellent catalytic performances for the acetalization of glycerol with acetone (95.8% of glycerol conversion, and 97.8% of solketal selectivity) at 20 °C, due to its high surface area with large number of acid sites. During recycling, the meso-MoO₂ catalyst exhibited a slight decrease in activity; and after a simple regeneration at 350 °C, the catalytic performances could be completely recovered. More importantly, a partial hydrophobic treatment of the meso-MoO₂ catalyst dramatically enhanced the water-tolerance during the catalytic reaction.