Foams Stabilized by AquivionTM PFSA: Application to Interfacial Catalysis for Cascade Reactions

Foams are attractive platforms for engineering gas–liquid–solid catalytic microreactors with enhanced triphasic contact. In this study, the foaming properties of surface-active Aquivion TM perfluorosulfonic acid resin (Aquivion TM PFSA) are unraveled. Stable aqueous and non-aqueous foams are prepared driven by hydrogen bond interactions between Aquivion TM PFSA and protic solvents (e.g., benzyl alcohol, aniline, water). In light of these unique properties, a catalytic foam system for one-pot cascade deacetalization–hydrogenation reactions is designed. As proof of concept, benzaldehyde dimethyl acetal is converted into benzyl alcohol with 84% overall yield at room temperature in a foam system in the presence of Aquivion TM PFSA and Pd/SiO 2 catalysts, whereas the yield is halved in a non-foam system. The enhanced reaction efficiency is attributed to a marked increase in interfacial area of the foam system and preferential location of catalytic acid centers at the gas–liquid interface.