Rational synergetic insight of Cs-Nb/Al2O3 toward promoted catalytic performance in aldol condensation of formaldehyde and methyl propionate

Acid-base properties and support effects are known to be instrumental in the formation of methyl methacrylate (MMA) upon the aldol condensation involving formaldehyde (FA) and methyl propionate (MP). In this work, four different alumina-supported Cs-Nb catalysts were fabricated and employed for the aldol condensation of FA and MP. It was noticed that Al2O3-B 2 O 3-B prepared by co-precipitation exhibited superior catalytic activity on account of its highest surface area and porosity as well as the highest content of Br & Oslash;nsted acid and five-coordinated Al. The comparison of integration manner revealed that closer proximity affords keener synergetic interaction, thereby multiplying catalytic performance. Furthermore, the association from acid-base characteristics to catalytic activity was established. Strikingly, the cutting-edge 10Cs-10Nb-Al2O3-B 2 O 3-B catalyst presented a single-pass lifetime of 150 h. The rational synergism in favor of lessening the energetic barriers for the processes of enolization and C-C bond formation was further verified by DFT calculations.