Aerobic Oxidation of Methyl Glycolate by α-Fe₂O₃ for the Eco-Friendly Synthesis of Methyl Glyoxylate

Methyl glyoxylate (MGO) is an important reagent for value-added chemical and pharmaceutical synthesis, but it urgently requires an eco-friendly synthesis method. Aerobic oxidation of massively obtainable methyl glycolate (MG) is an ideal nonpetrochemical route for MGO production. Herein, α-Fe₂O₃ with a hydroxyl-deficient surface obtained by a precipitation method is discovered to be an enabling catalyst with a markedly lowered reaction activation energy (88.6 kJ mol^-1), achieving a high specific activity of 0.26 g_MGO m_cat^-2 h^-1. The MG conversion of 80-85% and 90-92% MGO selectivity are obtained at 220 °C and can maintain stability throughout 100 h test. Isotope-labeling experiments and theoretical calculations confirm that this reaction proceeds over α-Fe₂O₃ following the MvK mechanism. The hydroxyl-deficient surface provides a warranty for such unprecedented catalytic performance, which in nature offers highly reactive lattice oxygen and abundant accessible Fe sites, thereby benefiting MG adsorption/activation, and is conducive to water desorption due to enhanced hydrophobicity.