Surface hydroxyl engineering induced construction of isolated Zr sites for selective methyl methacrylate production

Abstract Significant attention is paid to methyl methacrylate (MMA) synthesis via direct aldol reaction on supported Cs‐based catalysts; however, the structure of active sites is still unclear. Herein, the structural sensitivity of Zr sites toward MMA production through aldol condensation of methyl propionate with formaldehyde on Cs/Zr/SiO 2 was identified, which was affected by surface hydroxyl groups on SiO 2 . Isolated hydroxyl groups were discovered to induce the formation of well‐defined Zr sites, which facilitated MMA formation, while the dimeric Zr species led to the generation of undesired methylacrolein (MAL) byproduct. It was demonstrated that a higher proportion of medium and strong Lewis acid sites could suppress MAL production through sequential H‐transfer hydrogenolysis and condensation reaction. As a result, the selectivity and formation rate of MMA could be promoted by ~30% and ~2.5 folds after Zr site modification. Therefore, the local structure of active components is critical to the regulation of catalytic performance in MMA production.