Reaction Kinetics, Mechanisms and Catalysis, vol.136, no.1, pp.267-286, 2023 (SCI-Expanded)
Oxidation of glucose was investigated over bimetallic oxide catalysts with H2O2 at 70–90 °C in ethanol and water under atmospheric pressure. Bimetallic oxides, contain Zn, Ce, Al, Mg, Sr and Fe were synthesized with co-precipitation methods. Screening of these oxides were proceeded in ethanol and the most effective one was tested in a more natural solvent water for 6 h. Effects of crystal structure, calcination, metal loading, reaction time and temperature on catalytic activity and product selectivities were investigated. Glucose conversion reactions were also performed with and without O2 source as comparison. The most active and selective catalyst in ethanol at 70 °C was found as Mg–Al–cal (62% glucose conversion and 10.2% formic acid selectivity). Metal loadings (Cu/V) to Mg–Al–cal lowered the catalytic activity significantly. Mg–Al–cal, tested in water at 90 °C, provided almost 95% of organic acid (formic and acetic acid) selectivity with 38% conversion. Deactivation of Mg–Al–cal by product adsorption was also investigated by the addition of formic acid in ethanol at 70 °C. In the presence of formic acid, the catalyst exhibited 50% of glucose conversion and 78% of total organic acid selectivity (levulinic acid + lactic acid + formic acid) without using O2 source. Graphical abstract: [Figure not available: see fulltext.]