Selective Oxidation of Biomass-Derived Alcohols and Aromatic and Aliphatic Alcohols to Aldehydes with O(2)/Air Using a RuO(2)-Supported Mn(3)O(4) Catalyst

[Image: see text] Selective catalytic oxidation of carbohydrate-derived 5-hydroxymethylfurfural, furfuryl alcohol, and various aromatic and aliphatic compounds to the corresponding aldehyde is a challenging task. The development of a sustainable heterogeneous catalyst is crucial in achieving high selectivity for the desired aldehyde, especially using O(2) or air. In this study, a RuO(2)-supported Mn(3)O(4) catalyst is reported for the selective oxidation reaction. Treatment of MnO(2) molecular sieves with RuCl(3) in aqueous formaldehyde solution gives a new type of RuO(2)-supported Mn(3)O(4) catalyst. Detailed catalyst characterization using powder X-ray diffraction, N(2) adsorption, scanning and transmission electron microscopes, diffuse reflectance UV–visible spectrometer, and X-ray photoelectron spectroscopy proves that the RuO(2) species are dispersed on the highly crystalline Mn(3)O(4) surface. This catalytic conversion process involves molecular oxygen or air (flow, 10 mL/min) as an oxidant. No external oxidizing reagent, additive, or cocatalyst is required to carry out this transformation. This oxidation protocol affords 2,5-diformylfuran, 2-formylfuran, and other aromatic and aliphatic aldehydes in good to excellent yield (70–99%). Moreover, the catalyst is easily recycled and reused without any loss in the catalytic activity.