Iodate Option For Natural Gas Upgrading

Selective, low-temperature conversion of light alkanes to functionalized products other than olefins has been a long-standing challenge, one that has become more important with the recent boom in U.S. natural gas production. T. Brent Gunnoe of the University of Virginia described a new metal-free process in which simple iodate salts in combination with catalytic amounts of chloride selectively oxidize methane, ethane, and propane (J. Am. Chem. Soc. 2014, DOI: 10.1021/ja502657g). Gunnoe noted that the alkane conversions are better than 20% in protic solvents such as trifluoroacetic acid. The resulting trifluoromethyl esters can serve as precursors to alcohols. The reactions achieve 85% selectivity for monofunctionalized products over a range of temperatures and pressures suitable for industrial-scale production. “The successful functionalization of all three of the alkanes that are the primary components of natural gas is rare,” said Gunnoe, who is director of a DOE Energy Frontier Research Center that focuses on catalytic hydrocarbon functionalization. “While we do not yet have a definitive handle on the mechanism, we suspect the fact that a simple, inexpensive chloride salt can turn a known oxidant that normally works only poorly with alkanes into a very efficient reagent could be of substantial interest.”