Ammoxidation of ethylene to acetonitrile over vanadium and molybdenum supported zeolite catalysts prepared by solid-state ion exchange

Abstract

This work reports on the investigation of the influence of the parent zeolite topology (MFI, MOR and USY) on the ammoxidation of ethylene to acetonitrile over vanadium and molybdenum oxide supported zeolite catalysts. The physico-chemical properties were investigated by several characterization techniques such as XRD, N2-adsorption, 27Al MAS NMR, TEM, XPS, DR UV–vis, Raman and DRIFT spectroscopies and H2-TPR. From the catalytic results, V and Mo oxide species in USY and MOR zeolites led to less active catalysts when compared to MFI structure. These results suggest that the catalytic performances depend strongly on the zeolite structure and thus, the size of the formed metal oxide particles. The catalytic activity and selectivity are controlled by the porous structure and the chemical state of V and Mo species. The extent of dispersion and reducibility of supported M-Ox (MV or Mo) species are governed by the chemical identity of the support as detected by TPR analysis and optical absorption spectroscopy. The good catalytic performance of MFI-type zeolite might be related to the high dispersion of metal oxide species and to the internal pore space which permits an effective accessibility of the reactants.