Catalytic activity and characterization of V_2O_5/γ-Al_2O_3 for ammoxidation of m-xylene system

摘要

An ammoxidation of m-xylene was evaluated in a fixed-bed reactor using V_2O_5 on various oxides. Catalysts were prepared by wet impregnation method. At first, the loading of V_2O_5 was varied from 5 wt% to 20 wt% on γ-Al_2O_3 support to estimate the most effective amount of V_2O_5. Second, the effect of catalyst supports was examined at 10 wt% loading of V_2O_5. V_2O_5/TiO_2 and V_2O_5/SiO_2 catalysts were employed to compare the ammoxidation reaction with V_2O_5/ γ-Al_2O_3. Most catalytic activity was observed when γ-Al_2O_3 was used as a support. Careful characterization was followed by physicochemical techniques, such as BET measurement, X-ray diffraction (XRD), Raman spectroscopy and temperature-programmed reduction (TPR). The results provided the clue that monolayer V_2O_5 was favorably dispersed on the surface of γ-Al_3_O, up to 10 wt%, which led to the highest yield of isophthalonitrile (IPN).