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A series of Zr-Cs/SiO2 catalysts were synthesized using a simple impregnation method to trigger the vapor aldol condensation of methyl acetate with formaldehyde. The effects of zirconium precursor, textural structure, and acid–base properties on the catalytic activity were systematically investigated via various characterization techniques, such as the physical N2 adsorption, XRD, FT-IR, NH3-/CO2-TPD, Py-IR, XPS, TEM, solid-state NMR, UV–vis spectra, and in situ DRIFTS. The introduction of the Zr component increased the specific surface area and regulated the ratio between the acid and base site density, which was conducive to the improvement of the catalytic performance. The superior MA selectivity of 93.5% with a yield of 44.9% was achieved under the optimal condition. The in situ DRIFTS experiments revealed that the Lewis acid sites played a crucial role in reactant adsorption, while the kinetic studies confirmed that the activation energy of this aldol condensation was 65.0 kJ/mol. The best catalyst showed satisfied regeneration behavior during the 450 h time-on-stream test, rendering potential for industrial applications.
Deng et al. (Mon,) studied this question.