Ru/TiO2-photocatalysed synthesis of γ-butyrolactone from a furfural derivative under mild conditions

Synthesis of γ -butyrolactone (GBL) from renewable biomass resources under mild reaction condition with catalysis is attractive but challenging. Herein, we report the photocatalytic oxidation of the biomass-based furfural derivative tetrahydrofurfuryl alcohol (THFAL) to prepare GBL under light irradiation (365 nm) in air at room temperature. Utilising Ru/TiO 2 as the photocatalyst and air as the oxidant, a GBL yield as high as 73 % was achieved. The reaction mechanism was studied rigorously by performing photocatalyst performance evaluation, material characterisation, free-radical quenching reactions and electron spin resonance (ESR). In situ diffuse reflectance infrared Fourier transform spectroscopy was employed to detect intermediate products and elucidate the mechanism at the molecular level. Based on the in-situ monitoring results, we propose a pathway for the oxidation decarbonylation of THFAL to produce CO 2 and GBL.