Alternative Oxidants for the Catalytic Oxidative Coupling of Methane

The catalytic oxidative coupling of methane (OCM) to C₂ hydrocarbons with oxygen (O₂ -OCM) has garnered renewed worldwide interest in the past decade due to the emergence of enormous new shale gas resources. However, the C₂ selectivity of typical OCM processes is significantly challenged by overoxidation to CO_x products. Other gaseous reagents such as N₂ O, CO₂ , and S₂ have been investigated to a far lesser extent as alternative, milder oxidants to replace O₂ . Although several authoritative review articles have summarized OCM research progress in depth, recent oxidative coupling developments using alternative oxidants (X-OCM) have not been overviewed in detail. In this perspective, we review and analyze OCM research results reporting the implementation of N₂ O, CO₂ , S₂ , and other non-O₂ oxidants, highlighting the unique chemistries of these systems and their advantages/challenges compared to O₂ -OCM. Current outlook and potential areas for future study are also discussed.