Vapor phase condensation of methyl acetate with formaldehyde to preparing methyl acrylate over cesium supported SBA-15 catalyst

• Cesium ion-containing catalyst showed high catalytic activity.
• The Si–O–Cs species acts as a potentially catalytically active site.
• The suitable strength of Lewis acid–base favors aldol condensation reaction.
• The deactivated catalyst was completely regenerated by calcination.

A cesium ion-containing catalyst, on an SBA-15 mesoporous molecular support, was prepared by the impregnation method and applied to the aldol condensation of methyl acetate with formaldehyde. The catalyst showed high catalytic activity in the condensation reaction. XRD characterization indicated that the cesium nitrate below 5 wt% loading was highly dispersed on the SBA-15 support. FT-IR and XPS results confirmed that a Si–O–Cs species was formed on the surface of the catalyst. Pyridine-IR verified that an L-acid site existed on the surface. The NH3-TPD and CO2-TPD results indicated that weak Lewis acid–base pairs were loaded on the surface, and these weak acid–base active sites might favor the aldol condensation reaction. The 5Cs/SBA-15 catalyst demonstrated the highest (48.4%) conversion of methyl acetate reported and 95.0% selectivity for methyl acrylate. The deactivated catalyst was completely regenerated by calcination. The catalyst was regenerated nine times with a total operation time of more than 60 h, and the initial conversion of methyl acetate and the selectivity for methyl acrylate did not change. The high catalytic activity was mainly due to the suitable strength of weak acid–base properties, which were rooted in the Si–O–Cs species on the surface of the support.

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