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 gamma-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 O-2 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.

Automated summary

This study developed an efficient catalytic strategy using metal-free mesoporous graphitic carbon nitride as the photocatalyst and O-2 as the oxidant for the preparation of gamma-butyrolactone from tetrahydrofurfuryl alcohol and other furfural derivatives. The effects of various semiconductor catalysts, light sources, and reaction time were investigated, along with the reaction mechanism and pathway through control experiments and density functional theory calculations.