Microwave-Assisted Selective Oxidation of 1-Phenyl Ethanol in Water Catalyzed by Metal Nanoparticles Immobilized onto Supported Ionic Liquidlike Phases

Abstract

The catalytic activity of metal nanometallic particles (MeNPs) immobilized and stabilized onto supported ionic liquidlike phases is evaluated to develop Au- and Pd-based oxidation catalytic systems. Under similar conditions, AuNPs behave as more active catalysts than PdNPs. In these systems, the polymer support is not only an inert matrix. Indeed, the polymer is designed to play a pivotal role. The polymeric backbone adequately modified with ionic liquidlike moieties (supported ionic liquidlike phases, SILLPs) actively plays several roles, facilitating the stabilization of the metal nanoparticles, controlling the easy accessibility of the reagents/substrates to the active sites, and providing specific microenvironments for an efficient and selective absorption of the microwave electromagnetic irradiation. The structure of these supports can be tuned to adjust the catalytic efficiency of the MeNP–SILLP composites. For this purpose, the Taguchi methods represent, as shown here, a very valuable tool. In the search for more environmentally friendly conditions, the oxidation reactions could be performed by combining microwave heating (as energy source), water (as solvent), and hydrogen peroxide (as a benign oxidant), achieving a more sustainable process.