Direct Conversion of Methyl–Ethyl-Ketone into Olefins Precursors of Fuels and Chemicals over Supported Cu Catalysts

Abstract

As global demand for light olefins continues to increase, driven by expanding plastics production and the need for jet fuel precursors, biomass-derived oxygenates such as methyl-ethyl-ketone (MEK) have emerged as promising intermediates for olefin production. This study investigates the selective hydrodeoxygenation of MEK to butene over copper catalysts supported on Al2O3, SiO2, and SiO2–Al2O3, each offering distinct acid characteristics. Among the catalysts evaluated, 10Cu/SiO2–Al2O3 achieved the highest olefin selectivity (97.6%) while maintaining a high MEK conversion level (>80%) due to its acidity and favorable metal–support interactions. Further studies revealed that at temperatures above 210 °C, the reaction pathway progressively shifts from hydrodeoxygenation toward aldol-condensation, producing undesired carboxylic acids and ketones, while simultaneously accelerating deactivation through hard-coke formation. A scaled-up experiment using a 100 g catalyst batch demonstrated that 10Cu/SiO2–Al2O3 operated at 210 °C (1 atm, w8 h space velocity = 0.8 h–1, PMEK = 12%) sustains high conversion (∼90%) and olefin selectivity (94–97%) for more than 140 h, with full recovery of activity and selectivity after mild oxidative regeneration. These results establish 10Cu/SiO2–Al2O3 as a robust and scalable catalyst for MEK hydrodeoxygenation, offering mechanistic insight into activity, selectivity, and deactivation pathways critical for industrial implementation.