Activity and Kinetics of Ethanol-to-Acetone Conversion via Magnetic Induction Heating

The catalytic conversion of bioethanol to acetone offers a renewable alternative to the fossil-fuel-intensive cumene process but requires high temperatures (>400 °C) that drive catalyst deactivation. This study demonstrates that magnetically induced heating (MIH) enables substantial performance improvements over conventional furnace heating (CFH) for ethanol-to-acetone conversion using Fe2O3–ZnO catalysts. MIH achieved 68% acetone selectivity at operating temperatures about 60 °C lower than CFH. At 400 °C, MIH delivered 80% ethanol conversion with 68% acetone selectivity, while CFH provided 35% conversion and 60% selectivity, a 33.4% yield improvement, with carbonaceous deposition reduced by 40% after 15 h on stream. STEM imaging, VSM magnetometry, and XPS characterization confirm the catalyst’s spinel nanostructure, ferrimagnetic properties, and surface redox behavior under reaction conditions. Time-on-stream experiments reveal that MIH reduces coke deposition (3.05 wt % vs 5.05 wt % after 15 h), while postreaction XRD and XPS analysis of spent catalysts under both heating modalities show consistent phase transformation from γ-Fe2O3 to Fe3O4, indicating that MIH does not induce fundamentally different deactivation pathways but may offer kinetic advantages in coke resistance. Application of a static magnetic field (up to 160 mT) during regular heating produced no magnetic enhancement, confirming that the observed rate improvements originate from thermal rather than nonthermal magnetic effects. Similar apparent activation energies (Ea ≈165–174 kJ/mol for acetone production) and preserved water-inhibition kinetics confirm that the reaction mechanism remains unchanged across heating modalities. Instead, the 2.1–2.7-fold rate enhancement arises from localized thermal effects: transient temperature variations on catalyst particles near magnetic susceptors create microscale temperature gradients that increase reaction rates without altering the activation barrier. Kinetic analysis established ethanol dehydrogenation as the rate-determining step, with water exhibiting nonmonotonic effects, promoting acetone formation at low partial pressures (<0.03 atm) but inhibiting at high loadings through competitive site blocking. These findings demonstrate that electrified MIH offers a viable pathway toward decarbonizing acetone production from biomass feedstocks, achieving high selectivity at reduced operating temperatures through improved thermal management at the catalyst particle scale.