Metal-free Photocatalytic Aerobic Oxidation of Biomass-based Furfural Derivatives to Prepare γ-butyrolactone

Efficient catalytic oxidative C–C bond cleavage with dioxygen is useful and challenging to prepare oxygenated fine chemicals from biomass. Herein, we report a catalytic strategy for the preparation of γ-butyrolactone (GBL) by photocatalytic oxidation of tetrahydrofurfuryl alcohol (THFA), tetrahydrofurfuric acid (THFCA), or other furfural derivatives at room temperature under visible-light irradiation. Metal-free mesoporous graphitic carbon nitride was used as the photocatalyst and O2 was used as the oxidant. The effects of various semiconductor catalysts, light sources with different wavelengths, and the reaction time on the photocatalytic oxidation of THFA to GBL were separately investigated. Furthermore, the reaction mechanism was investigated through serious control experiments and the reaction pathway was investigated through density functional theory (DFT) calculations.