Aerobic oxidation of 5-hydroxymethylfurfural to 2,5-diformylfuran on supported vanadium oxide catalysts: Structural effect and reaction mechanism

Abstract

The structure–activity relationship and reaction mechanism for selective oxidation of 5-hydroxymethylfurfural (HMF) to 2,5-diformylfuran (DFF) in toluene were studied on vanadium oxide domains on TiO2, Al2O3, Nb2O5, ZrO2, and MgO and with a wide range of VOx surface densities. The structures of these catalysts were characterized by X-ray diffraction (XRD), diffuse reflectance UV–vis spectroscopy (UV–vis DRS), and Raman spectroscopy, and their reducibility was probed by H2-temperature programmed reduction. The structures of the VOx domains evolved from monovanadate to polyvanadate structures with increasing the VOx surface densities, and finally to crystalline V2O5 clusters at surface densities above one-monolayer capacity. Within one-monolayer capacity, higher VOx surface densities and more reducible supports led to higher reducibility and reactivity of the VOx domains. The support surfaces covered with polyvanadates and V2O5 clusters and the supports with acidity favored the formation of DFF. The correlation between the reducibility and reactivity, together with the kinetic studies, suggests that the HMF oxidation to DFF proceeds via the redox mechanism involving the V5+/V4+ redox cycles and the reoxidation of V4+ to V5+ by O2 as the rate-determining step. These results may provide guidance for the design of more efficient catalysts for the HMF oxidation to synthesize DFF.

Catalytic Performance of Zeolite‐Supported Vanadia in the Aerobic Oxidation of 5‐hydroxymethylfurfural to 2,5‐diformylfuran

“…This is the first time that this kind of study of the leaching and homogeneous contribution of supported vanadium catalyst has been performed for this reaction 17. 32, 42…”

“…To overcome these drawbacks, UV Raman spectroscopy was employed 32. The excitation laser wavelength was selected to 244 nm to obtain a resonance Raman effect.…”

Metal Catalysts for the Efficient Transformation of Biomass‐derived HMF and Furfural to Value Added Chemicals

“…One of the most important oxidized products of HMF is FDCA, which has huge prospective in the production of bio‐based polymer analogous to polyethylene terephthalate (PET) and polybutylene terephthalate (PBT), as a substitute for the petroleum‐derived terephthalic acid . Moreover, the partially oxidized form of HMF, the 2,5‐diformylfuran (DFF) is also an important starting material used for the production of polymers, fungicides, pharmaceuticals and so on …”

Advances in selective catalytic transformation of ployols to value-added chemicals

“…It was demonstrated that Cu(NO3)2 facilitates the generation of V V species from VOSO4 and a V V /V IV redox cycle was involved. Recently, Liu and coworkers [104] also found that HMF oxidation to DFF proceeds via the redox mechanism involving V V /V IV redox cycles and the reoxidation of V IV to V V by O2 was the rate determining step.…”