Fe-Based Metal–Organic Frameworks for Highly Selective Photocatalytic Benzene Hydroxylation to Phenol

Abstract

Phenol is one of the most important chemicals in industry. One-step selective benzene hydroxylation is an attractive yet challenging method for phenol production, especially when such a reaction can be driven by solar energy. Herein, we reported that a highly selective benzene hydroxylation to phenol can be achieved over two Fe-based metal–organic frameworks [MIL-100(Fe) and MIL-68(Fe)] under visible light irradiations using hydrogen peroxide (H2O2) as an oxidant. An optimal benzene conversion of 30.6% was achieved with a H2O2:benzene ratio of 3:4 over MIL-100(Fe) after 24 h irradiations. ESR results and the kinetic studies suggested that a successful coupling of the photocatalysis of Fe–O clusters in Fe-based metal–organic frameworks (MOFs) with a Fenton-like route is involved in this benzene hydroxylation process. The comparison of the reaction over MIL-100(Fe) and MIL-68(Fe) reveals that the structure of MOFs significantly influences the photocatalytic efficiency. Because the composition and the struct...