Liquid Phase Nitration of Benzene Catalyzed by a Novel Salt of Molybdovanadophosphoric Heteropolyacid

A highly efficient and reusable catalyst QA-HPMV was successfully prepared by the reaction of quinoline-2-formic acid (QA) with molybdovanadophosphoric heteropolyacid (H₄PMo₁₁VO₄₀, HPMV) for the nitration of benzene. The physical and chemical properties of the sample was characterized by X-ray diffraction analysis (XRD), Fourier transform infrared spectroscopy (FTIR), UV-Vis and thermogravimetric analysis (TG). The characterization results showed that the formed QA-HPMV retained the Keggin structure of HPMV. As a catalyst for benzene nitration, QA-HPMV showed good catalytic performance and the yield of nitrobenzene was 82.5% under the optimized reaction conditions. As a heterogeneous catalyst, QA-HPMV can be easily recycled from the reaction medium by filtering and remained highly catalytic performance even after five runs of recycling.

Keywords:
molybdovanadophosphoric heteropolyacid; solid acid; catalysis; benzene; liquid phase nitration