Magnetic Nanoparticles with In Situ Surface Growing Polymeric Brushes as Reactive Pickering Interfacial Catalysts for Biphasic Reactions

The intensification of catalytic reaction and droplet manipulation in a liquid–liquid (L–L) biphasic system has been widely focused in this research. The surface engineering of magnetic materials offers a reasonable tactic for the design of magnetic Pickering interfacial catalysts (MPICs), which substantially bridges the gap of homogeneous and heterogeneous catalysis for promoting efficient and selective transformation of resources. In this study, we control the growth of organic base monomer brushes by surface-initiated reversible addition–fragmentation chain transfer (SIRAFT) polymerization to afford a magnetopolymeric nanocatalysts Fe3O4@PS-PM. The surface engineering strategy enables us to simply tune the surface wettability and active site content for the manipulation of emulsion catalysis. In a biphasic reaction system (i.e., transesterification and epoxidation), the catalytic performance of an emulsion system is more than twice that of an unemulsified system, which is attributed to the enhancement effect of the Pickering emulsion microenvironment. In addition, the inherent paramagnetism demonstrates that MPICs can be swiftly desorbed and recovered from the oil–water interface and showed attractive catalytic activity and stability over five runs. The practical surface engineering has promising prospects for construction and adjustment of magnetically separable PICs and enables accessible manipulation of green chemical transformation based on a versatile Pickering emulsion platform.