Selective Oxidation of Biomass-Derived Alcohols and Aromatic and Aliphatic Alcohols to Aldehydes with O₂/Air Using a RuO₂-Supported Mn₃O₄ Catalyst

Abstract

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.

Heterostructured manganese catalysts for the selective oxidation of 5‐hydroxymethylfurfural to 2,5‐diformylfuran

“…Among the solvents employed, MnOx−A−U in water as solvent afforded the lowest yield of DFF (9.6 %). Non‐polar solvent toluene gave a comparable yield of DFF (29.1 %) which was only 3.0 % lower than that obtained in ethanol under similar reaction condition, as toluene might facilitate the interaction between the active site in the catalyst and the substrate as proposed in the previous study . For comparison, we have also synthesized two different reported Mn‐based materials such as MnOx/P25 and Mn 0.5 +Co 0.5 according to their procedure and employed as catalysts under the optimised reaction conditions in the present study (Table S5).…”

“…As solvent plays an important role in the oxidation of HMF to DFF, various polar protic, polar aprotic and non‐polar solvents have been reported . The various solvents, such as water, methanol, acetone, ethyl acetate and toluene were used for the oxidation of HMF with MnOx−A−U, and the results are presented in Figure .…”

Catalytic Enhancement of Inductively Heated Fe3O4 Nanoparticles by Removal of Surface Ligands

“…The pyridine treated samples outperform as‐synthesized NPs thermally and inductively, increasing aldehyde yield by 4x, and demonstrating the benefits of removing capping ligands in induction heating catalysis (Table 1). Further improvements in conversion could likely be achieved using traditional promoters, solvents, and high‐pressure systems but are beyond the scope of this work [19a,d,27] . Comparatively, previous reports [19b,c] using Fe 3 O 4 as a dehydrogenation catalyst display low yields (1 %) at much higher temperatures (345 °C, via thermal heating), suggesting that the required amount of energy for initial activation of Fe 3 O 4 can be achieved at lower bulk temperatures by induction heating.…”

When sonochemistry meets heterogeneous photocatalysis: designing a sonophotoreactor towards sustainable selective oxidation

“…A characteristic paradigm for the latter conversion is the selective oxidation of biomassderived alcohols, such as aromatics and furanics, to their corresponding carbonyl counterparts (aldehydes and car-boxylic acids). [4][5][6][7][8] A promising and advantageous method towards the above-mentioned direction is the exploitation of the most available natural power source, sunlight. The utilization of light for catalytic reactions led to a research field known as photocatalysis.…”