Support effects of Cs/Al2O3 catalyzed aldol condensation of methyl acetate with formaldehyde

In this work, the support effects on vapor-phase aldol condensation of methyl acetate (MeOAc) with formaldehyde (HCHO) over cesium catalysts are understood by the employment of Al2O3 with different morphologies and crystal phases. The structural and electronic properties of these supported Cs catalysts are characterized by multiple techniques, such as XRD, HAADF-STEM, EDS-mapping, XPS, NH3-TPD and CO2-TPD. The Cs species are found to be highly dispersed on the Al2O3 surfaces, and their compositions vary with the identity of Al2O3. A combined catalyst characterization and testing results indicates a balance between acidic and basic sites, i.e., an acid-base synergy, for the production of MA: the excess acidic sites lead to the lower MA selectivity due to the promoted further condensation, while the excess basic sites with the lower MeOAc conversion due to the insufficient activated HCHO species. These insights could be valuable for the design and optimization of catalysts for this reaction.

Automated summary

The study explores the support effects of cesium catalysts on the vapor-phase aldol condensation of MeOAc with HCHO using Al2O3 with different morphologies and crystal phases. The research shows that a balance between acidic and basic sites is crucial for the production of MA in this reaction.