Design of Glycerol-Based Solvents for the Immobilization of Palladium Nanocatalysts: A Hydrogenation Study

Twenty-one green solvents, including glycerol-derived ethers, and their eutectic mixtures with two renewable ammonium salts, were used for the straightforward synthesis, stabilization, and immobilization of palladium nanoparticles (Pd NPs). The nature of the solvent allows tuning of the characteristics and properties of resulting catalytic systems in terms of particle size and morphology, stability, reactivity, and recoverability. Pd NPs immobilized in glycerol-based solvents were applied in the catalytic hydrogenation of alkenes, alkynes, and carbonyl compounds, as well as in the selective semihydrogenation of alkynes to alkenes. The optimal experimental parameters and the influence on the reactivity of the physicochemical properties of solvent, mainly the viscosity, were studied. Moreover, the most active and recoverable catalytic system, Pd NPs/N00Cl-100, was fully characterized both in the liquid phase and in the solid state, and its deactivation upon recovery was analyzed.

Automated summary

Twenty-one green solvents, including glycerol-derived ethers, were used for the synthesis and immobilization of palladium nanoparticles (Pd NPs) in catalytic reactions. The choice of solvent allowed tuning of the properties of resulting catalytic systems, and Pd NPs immobilized in glycerol-based solvents showed promising results in hydrogenation and selective semihydrogenation reactions. The influence of solvent properties, particularly viscosity, on reactivity was studied, leading to the identification of the most active catalytic system.