Scalable and recyclable all-organic colloidal cascade catalyst

Chen C, Janoszka N, Wong CK, Gramse C, Weberskirch R, Gröschel AH

Abstract

We report on the synthesis of core‐shell microparticles (CSMs) with an acid catalyst in the core and a base catalyst in the shell by surfactant‐free emulsion polymerization (SFEP). The organocatalytic monomers were separately copolymerized in three synthetic steps allowing the spatial separation of incompatible acid and base catalysts within the CSMs. Importantly, a protected and thermo‐decomposable sulfonate monomer was used as acid source to circumvent the neutralization of the base catalyst during shell formation, which was key to obtain stable, catalytically active CSMs. The catalysts showed excellent performance in an established one‐pot model cascade reaction in various solvents (also water) that involves an acid‐catalyzed deacetalization followed by a base‐catalyzed Knoevenagel condensation. The CSMs are easily recycled, modified, and their synthesis is scalable, which makes them promising candidates for organocatalytic applications.