Catalysis Letters, Vol.149, No.9, 2408-2414, 2019
Highly Selective Visible-Light Photocatalytic Benzene Hydroxylation to Phenol Using a New Heterogeneous Photocatalyst UiO-66-NH2-SA-V
A new heterogeneous catalyst UiO-66-NH2-SA-V was prepared by the vanadium oxyacetylacetonate anchored on the Schiff base UiO-66-NH2-SA with chemical bonds. The liquid-phase oxidation of benzene to phenol over UiO-66-NH2-SA-V as a heterogeneous photocatalyst was studied under visible light. A mixed solvent of acetonitrile and acetic acid was chosen as the preferred solvent and hydrogen peroxide was chosen as an ecofriendly oxidant. Under optimized conditions, the photocatalyst showed benzene conversion of 15.3% at a phenol selectivity of 100%, giving no dihydroxylated byproducts. The synthesized material was characterized by scanning electron microscopy, transmission electron microscopy, FT-IR, X-ray powder diffraction and nitrogen adsorption-desorption. The effects of different parameters on the catalytic performance of UiO-66-NH2-SA-V were investigated. The anchor effect of vanadium oxyacetylacetonate stabilized and inhibited the leak of vanadium, leading to good catalytic recyclability with almost unchanged catalytic efficiency after five recycling tests in the acid reaction condition. The excellent catalytic performance of UiO-66-NH2-SA-V was due to the integration of vanadium species with high catalytic activity and the UiO-66-NH2 support in their interaction with the benzene substrate. [GRAPHICS] .