Highly Dispersed ZrO2 Modified Cs/SiO2-Based Catalyst via Ligand–Assisted Strategy for Aldol Condensation of Methyl Acetate with Formaldehyde

AbstractA kind of highly dispersed ZrO2 modified Cs/SiO2-based catalyst was prepared via ligand–assisted impregnation strategy. The catalyst was then used to the aldol condensation reaction of methyl acetate (MAc) with formaldehyde (FA) to produce methyl acrylate (MA). The effect of highly dispersed ZrO2 promotion on Cs/SiO2 catalyst selectivity and activity was studied as well. Various techniques such as XRD, FT-IR, TEM, XPS, NH3-TPD, CO2-TPD, N2 physical adsorption, and solid-state MAS NMR were used to characterize the structural features, Cs species states, and acid–base properties of these catalysts. The use of Zr(acac)4 as a zirconium source for modifying Cs/SiO2 could be considered optimal for ligand-assisted impregnation. By modifying the highly dispersed ZrO2, more Cs–O–Si species and a suitable balance of acid–base sites were formed in the Zr–Cs/SiO2 catalyst. As a result, the catalyst showed significant improvements in selectivity and yield of MA under optimized reaction conditions. This study is beneficial for the development and optimization of catalysts for aldol condensation and provides a reference for future industrial applications.