Metal-doped M-NH4-PW catalyst with enhanced electron transfer for formaldehyde-propylene condensation to 4-methyl-1,3-dioxane

Abstract

Recognizing and modifying the acid property-dependent catalytic characteristics of catalysts are of great importance for Prins condensation reaction. Herein, a series of metal-doped M-NH4-PW catalysts (M=Pt, Fe, Ir, Ru) are successfully synthesized for Prins condensation reaction of formaldehyde and propylene to produce 4-methyl-1,3-dioxane. Our findings demonstrate that the catalytic performance of M-NH4-PW catalysts is influenced by the chemical nature of metal site properties with different electron transfer abilities. Specifically, the new Lewis acid decorated by Pt metal on 4-H site is more favorable for the selective adsorption of formaldehyde and activation of its CO bond. Additionally, the synergistic effect between Pt metal sites and nearby O in [PW12O40]3− promotes the formation of CC bonds between protonated formaldehyde and propylene. Consequently, the Pt-NH4-PW catalyst exhibits high conversion (> 80 %) and simultaneous selectivity towards 4-methyl-1,3-dioxane selectivity (65 %). This strategy may provide valuable insights for developing efficient multifunctional catalysts for Prins condensation reactions.