3D hierarchical flower-like MgO catalysts for dimethyl carbonate production from the transesterification of propylene carbonate with methanol

This study aimed to optimize the catalytic activity of MgO for dimethyl carbonate (DMC) production via the transesterification of propylene carbonate (PC) with methanol. MgO catalysts were prepared via precipitation under various basic conditions. The well-defined, 3D hierarchical, flower-like MgO catalyst, synthesized using K 2 CO 3 as the precipitant at 80 °C and calcined at 500 °C for 5 h, exhibited superior activity compared with commercial MgO and catalysts with other morphologies. It achieved a PC conversion of 73.4%, DMC selectivity of 95.3%, and DMC yield of 72.8%. The enhanced performance was attributed to the unique flower-like structure, which consisted of assembled flakes formed by primary nanocrystalline MgO. This architecture provided a complex pore structure and a high specific surface area (83.21 m 2 .g –1 ), facilitating the reactant transport to the catalyst surface. Furthermore, the small MgO crystallite size (5.8 nm) resulted in a higher proportion of surface defects of acidic and basic sites (10.79 and 2.65 mmol.g –1 ) for adsorbing and activating PC and methanol. These results demonstrate that the synergistic effects of the complex hierarchical pore structure and the appropriate number of acid-base sites in the flower-like MgO catalyst play key roles in enhancing DMC production.