PEG-assisted synthesis of highly dispersed Cs/Zr-SiO2 catalyst for aldol condensation of methyl acetate with formaldehyde

The dispersion of active sites plays an imperative role in the promotion of catalytic performance on methyl acrylate synthesis via direct vaporous aldol condensation. Herein, a novel PEG-assisted impregnation method was proposed to synthesize Cs/Zr-SiO 2 catalyst with high dispersion of acid and base sites. A series of characterization techniques including NMR, TEM, physical N 2 adsorption isotherms, XRD, XPS, NH 3 -/CO 2 -TPD, and Py-IR were used to investigate the physico-chemical properties of these prepared catalyst series. The introduction of PEG improved the specific surface area, dispersion of active sites, and density of acid and base sites, resulting in superior catalytic performance of Cs/PEG@Zr-SiO 2 by comparison with that of Cs/SiO 2 and Cs/Zr-SiO 2 . The kinetic experiments revealed that the activation energy of aldol condensation was 80.8 kJ/mol over the Cs/PEG@Zr-SiO 2 catalyst. The deactivation behavior derived from carbon deposition was discovered, and the spent catalyst could be regenerated by simple thermal treatment.