Hydrothermal Glucose Modified C/V-SiO2 as a Reusable Heterogeneous Catalyst for Benzene Oxidation to Phenol by O2

The C/V-SiO2 samples were synthesized by the hydrothermal treatment of aqueous glucose and V-SiO2 that was pre-prepared by a sol-gel process. The samples were characterized by XRD, XPS, EPR, FT-IR, SEM, N-2 adsorption-desorption. The results showed that in the hydrothermal process the V-SiO2 was covered by a rod-like carbonization material, and a small portion of V5+ species was reduced to V4+. The activity of the C/V-SiO2 in benzene hydroxylation with O-2 was tested. The leaching of V from the C/V-SiO2 during the reaction was restrained because the surface of the V-SiO2 was covered with the carbonization material. The phenol selectivity of 100% and benzene conversion of 10.8% over C/V(3.9)-SiO2 were obtained, and the catalytic performance did not decreased after being recycled three times. The leaching of V from the C/V-SiO2 was restrained in the hydroxylation of benzene with O-2 because the surface of V-SiO2 was covered with the carbonization material.