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 AquivionTM perfluorosulfonic acid resin (AquivionTM PFSA) are unraveled. Stable aqueous and non‐aqueous foams are prepared driven by hydrogen bond interactions between AquivionTM 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 AquivionTM PFSA and Pd/SiO2 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. AquivionTM PFSA, a family of perfluorosulfonic acid resins, could stabilize aqueous and non‐aqueous foams. When combined with Pd/SiO2, an aqueous foam is designed for the cascade deacetalization–hydrogenation reaction of benzaldehyde dimethyl acetal to benzyl alcohol with 84% yield, whereas it is halved without foam. This difference is attributed to both higher interfacial area and location of acid centers at the gas–liquid interface.