Amphiphilic Graft Copolymer-Templated Pd Nanoparticles: A Highly Recyclable Catalyst for Greener Mizoroki–Heck Reaction

We report easily recyclable Pd nanoparticle (PdNP) catalysts embedded within an amphiphilic graft copolymer designed with dual functionality: high dispersion stability and facile isolation via centrifugation. The graft copolymer, synthesized through the reaction of poly(styrene-alt-maleic anhydride) with amine-terminated polyether, effectively controlled the Pd nucleation and growth of PdNPs via mild reduction with methanol. This process yielded uniform, catalytically active PdNPs integrated within the copolymer matrix. The amphiphilic polyether chains ensured dispersion stability, whereas the carboxylate moieties served as Pd-coordination sites. This polymer facilitated both the hybridization of Pd with the polymer chains and the interparticle interactions required for centrifugal precipitation. Compared with conventional heterogeneous Pd catalysts, this catalyst enabled the Mizoroki–Heck reaction at lower temperatures using butanol as a safer solvent, resulting in a 34.2% reduction in Global Warming Potential (GWP) and a 47.3% reduction in the total primary energy demand compared to the conventional DMF system. The catalyst achieved a turn over number (TON) of 64.3 and a turnover frequency (TOF) of 3.22 h−1. The excellent recoverability of rare Pd without loss of activity, combined with the results of a life cycle assessment, demonstrates a practical approach to recyclable heterogeneous catalysis with a reduced environmental footprint.