Selective oxidation of tetrahydrofurfuryl alcohol to (S)-5-(hydroxymethyl)dihydrofuran-2(3H)-one by Ag-CeO_x/γ-Al₂O₃ catalyst

Tetrahydrofurfuryl alcohol (THFA) is a platform compound for green and sustainable development, and the conversion from THFA to high-value-added chemicals is a research hotspot at present. Herein, a scheme for the synthesis of (S)-5-(hydroxymethyl)dihydrofuran-2(3H)-one (2H-HBO) from THFA was proposed for the first time. The Ag-CeO_x/γ-Al₂O₃ catalyst was prepared by the impregnation method. The X-ray diffraction pattern indicates the presence of cerium oxide and silver metal nanoparticles with a fluorite structure on the surface of the γ-Al₂O₃ support. Scanning electron microscopy indicates that the support is encased with metal nanoparticles and the average particle size of the catalyst is 5–26 nm. Transmission electron microscopy indicates that Ag⁰ exists in a dispersed state. The CeO₂/Ce₂O₃ redox pair was formed on the outer surface of the vector. Energy dispersive spectroscopy demonstrated that the silver and cerium nanoparticles are relatively evenly distributed on the support. X-ray photoelectron spectroscopy demonstrated the presence of Ce³⁺/Ce⁴⁺ on the surface of the catalyst, confirming the presence of Ag⁰. NH₃-temperature programmed desorption and pyridine adsorption Fourier-transform infrared demonstrate the presence of 0.0708 mmol g⁻¹ L-acid and 0.0028 mmol g⁻¹ B-acid acid sites on the surface of the catalyst. GC–MS shows that the main oxidation product of aerobic oxidation of THFA is 2H-HBO with a yield of 87.8%. The reaction mechanism of 2H-HBO formation from ring-opening and then cyclization of THFA was revealed. We present a solvent-free, 100% conversion method of THFA. This study provides an efficient and novel scheme for realizing the high valorization of biomass derivatives.