Influence of Al Oxides on Cs-SiO2 Catalysts for Vapor Phase Aldol Condensation of Methyl Acetate and Formaldehyde

A novel Al-promoted Cs-SiO2 catalyst was synthesized via impregnation methods and applied in the aldol condensation reaction of methyl acetate (Ma) with formaldehyde (FA) to synthesize methyl acrylate (MA). Promotion effects of Al oxides on Cs-SiO2 catalysts were systematically investigated. The physical–chemical properties of synthesized catalysts were characterized through XRD, FT-IR, EDS mapping, N2 physical adsorption, NH3-/CO2-TPD, Py-IR, XPS, solid-state MAS NMR, and TG. Subsequently, the catalytic performance of fabricated catalysts was evaluated in a fixed-bed microreactor. Reaction parameters, Cs2O and Al2O3 contents, as well as calcination temperature were optimized. The evaluation of catalytic stability was conducted under optimal reaction conditions. As a result, the introduction of Al species into Cs-SiO2 endowed the Al–Cs–SiO2 catalyst with superior catalytic performance and good reusability.