Highly selective Sn/HZSM-5 catalyst for ethane ammoxidation to acetonitrile and ethylene

Abstract The ammoxidation of ethane over the conventional metal oxide and Co/zeolite catalysts faces the challenge of inadequate selectivity owing to the formation of CO2, N2, and NOx. Here we report that Sn modified ZSM-5 catalyst is highly selective for ethane ammoxidation. The C- and N-based acetonitrile selectivities are up to 80% and 70% over the Sn/HZSM-5, but they are below 60% and 20%, over the Co/HZSM-5. We suggested that the Sn (IV) cations are the critical active sites for acetonitrile formation, and the presence of nanosized SnOx particles favors CO2 formation. Transient kinetics analysis suggested that ethane ammoxidation over the Sn/HZSM-5 follows the same reaction pathways as that over the Co/HZSM-5. However, the surface abundancy of the reaction intermediates over these two catalysts is different, which could be the reason for the enhanced selectivity over the Sn (IV) cations in contrast to the Co (II) cations in the ZSM-5 zeolite.