One-pot cascade production of 2,5-diformylfuran from glucose over catalysts from renewable resources

Abstract

Lignocellulosic biomass is a potential sustainable feedstock to replace fossil fuels. Utilization of lignocellulosic biomass in a green and effective way is of great significance for sustainable development. The direct, one-pot, one-step catalytic conversion of glucose to 2,5-diformylfuran is a challenging task. In this work, Al(NO₃)₃ has been heterogeneously supported on porous carbon derived from Na-lignosulfonate or a mixture of Na-lignosulfonate and Na-polystyrene sulfonate via ice-templating, mild pyrolysis (350 and 450 °C) and H⁺ exchange techniques to obtain bifunctional carbocatalysts (Al(NO₃)₃@LH or Al(NO₃)₃@LH–PH). The catalysts were characterized by Fourier transform infrared (FT-IR), pyridine adsorption infrared (Py-IR), X-ray diffraction (XRD), X-ray photoelectron spectra (XPS), field emission scanning electron microscopy (FE-SEM), energy dispersive X-ray spectroscopy (EDS) and Brunauer–Emmett–Teller (BET) analyses. A novel one-step cascade method of producing DFF directly from glucose through the binary catalyst Al(NO₃)₃@LH or Al(NO₃)₃@LH–PH with AlBr₃ in 99% DFF yield without the need for a strong oxidant is described. Mechanistic studies show that the cascade conversion of glucose involves isomerization, dehydration and successive Kornblum-type oxidation. Moreover, the catalysts could be reused in consecutive runs, exhibiting a slightly lower activity in the synthesis of DFF from glucose.