Magnetically Induced Iron-Catalyzed Hydrodeoxygenation of Benzylic Esters and Polyesters.

The selective hydrodeoxygenation of benzylic esters with molecular hydrogen (H2) provides a synthetic approach to methyl-substituted aromatic compounds used widely as intermediates and products in the chemical and pharmaceutical industries in accordance with green chemistry principles. In particular, it can open novel pathways for the use of biomass-derived substrates or waste plastics as chemical feedstocks. We present here an efficient catalytic approach focusing on the use of earth abundant iron in the form of iron carbide nanoparticles (ICNPs) activated by magnetic induction, allowing the reaction to proceed at pressures of only 3 bar of H2. The activity of the ICNPs responds in real time to on/off switches of the alternating current magnetic field (ACMF, 350 kHz, 70 mT), mimicking the use of intermittent renewable electricity, and the magnetic properties of the ICNPs allow for their easy separation and reuse. The reaction proceeds with higher yield and selectivities at global temperatures more than 130 °C below thermal activation, leading to at least four times higher energy efficiency. The method was successfully applied to a range of synthetic targets and to the selective depolymerization of real polyester (PET) products.