High Ethylene‐Yield Oxidative Dehydrogenation of Ethane Using Sulfur Vapor as a “Soft” Oxidant

Abstract

AbstractEthylene remains one of the most valuable chemical feedstocks. Currently the industrial conversion of ethane to ethylene is achieved largely by steam cracking. The catalytic, highly exothermic oxidative dehydrogenation (ODH) of ethane with O2 is a challenging alternative that has been extensively studied on the laboratory scale. Here we investigate the possibility of using disulfur (S2) vapor as a thermodynamically “soft” oxidant for catalytically converting ethane to ethylene (“SODH”). Investigating a series of four catalysts we report a maximum ethylene yield of 76 % over an earth‐abundant FeSx‐based catalyst (maximum 90.2 % C2H4 selectivity at 820 °C). Yield and selectivity are stable for 50 hours on stream. The SODH rate law is 1st order in ethane and order in S2, supporting a proposed Mars van Krevelen‐like mechanism at temperatures <700 °C. Furthermore, conversion and selectivity become insensitive to catalyst identity at temperatures >860 °C, suggesting the intrusion of radical pathways.