title: Selective monooxidation of light alkanes using chloride and iodate.
abstract: We describe an efficient system for the direct partial oxidation of methane, ethane, and propane using iodate salts with catalytic amounts of chloride in protic solvents. In HTFA (TFA = trifluoroacetate), >20% methane conversion with >85% selectivity for MeTFA have been achieved. The addition of substoichiometric amounts of chloride is essential, and for methane the conversion increases from <1% in the absence of chloride to >20%. The reaction also proceeds in aqueous HTFA as well as acetic acid to afford methyl acetate. (13)C labeling experiments showed that less than 2% of methane is overoxidized to (13)CO2 at 15% conversion of (13)CH4. The system is selective for higher alkanes: 30% ethane conversion with 98% selectivity for EtTFA and 19% propane conversion that is selective for mixtures of the mono- and difunctionalized TFA esters. Studies of methane conversion using a series of iodine-based reagents [I2, ICl, ICl3, I(TFA)3, I2O4, I2O5, (IO2)2S2O7, (IO)2SO4] indicated that the chloride enhancement is not limited to iodate.
authors.affiliation: Department of Chemistry, University of Virginia , Charlottesville, Virginia 22904, United States.
authors.forename: George C
authors.initials: GC
authors.lastname: Fortman
authors.forename: Nicholas C
authors.initials: NC
authors.lastname: Boaz
authors.forename: Dominik
authors.initials: D
authors.lastname: Munz
authors.forename: Michael M
authors.initials: MM
authors.lastname: Konnick
authors.forename: Roy A
authors.initials: RA
authors.lastname: Periana
authors.forename: John T
authors.initials: JT
authors.lastname: Groves
authors.forename: T Brent
authors.initials: TB
authors.lastname: Gunnoe