Manganese Catalyzed Partial Oxidation of Light Alkanes
- Univ. of Virginia, Charlottesville, VA (United States)
- California Institute of Technology (CalTech), Pasadena, CA (United States)
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
- Princeton Univ., NJ (United States)
- Argonne National Lab. (ANL), Lemont, IL (United States)
- San Rafael, CA (United States)
The catalytic partial oxidation of methane is achieved at low temperatures (<200 °C) using manganese oxides and manganese salts in mixtures of trifluoroacetic acid and trifluoroacetic anhydride. Dioxygen is used as the in situ terminal oxidant. For Mn oxides (e.g., MnO2, Mn2O3, and Mn3O4), we studied stoichiometric methane partial oxidation in HTFA (TFA = trifluoroacetate). Using a Mn trifluoroacetate salt, at 180 °C and under 25 psig of methane, product selectivity for the mono-oxidized product methyl trifluoroacetate (MeTFA) is observed to be >90% at ~35% methane conversion at approximately 6 turnovers. Under our catalytic methane oxidation reaction conditions, MeTFA is stable against overoxidation, which explains the likely high selectivity at conversions >15%. Using combined experimental studies and DFT calculations, a mechanism involving soluble and molecular Mn species in the catalytic cycle is proposed. The proposed reaction pathway involves initial activation of MnII by dioxygen, cleavage of a methane C–H bond by a MnIII hydroxo intermediate, rebound of the methyl radical to generate MeTFA, and finally regeneration of the starting MnII complex. Also, this process is shown to be applicable to the oxidation of ethane, favoring the mono-oxidized product ethyl trifluoroacetate (EtTFA) and reaching ~46% conversion.
- Research Organization:
- Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
- Sponsoring Organization:
- National Science Foundation (NSF); USDOE Office of Energy Efficiency and Renewable Energy (EERE), Energy Efficiency Office. Advanced Manufacturing Office
- Grant/Contract Number:
- AC02-06CH11357; AC05-00OR22725
- OSTI ID:
- 1883785
- Journal Information:
- ACS Catalysis, Journal Name: ACS Catalysis Journal Issue: 9 Vol. 12; ISSN 2155-5435
- Publisher:
- American Chemical Society (ACS)Copyright Statement
- Country of Publication:
- United States
- Language:
- English
Similar Records
Selective Monooxidation of Light Alkanes Using Chloride and Iodate
Aerobic Partial Oxidation of Alkanes Using Photodriven Iron Catalysis
Selective Photo‐Oxygenation of Light Alkanes Using Iodine Oxides and Chloride
Journal Article
·
Tue May 27 20:00:00 EDT 2014
· Journal of the American Chemical Society
·
OSTI ID:1607836
Aerobic Partial Oxidation of Alkanes Using Photodriven Iron Catalysis
Journal Article
·
Mon Dec 27 19:00:00 EST 2021
· Inorganic Chemistry
·
OSTI ID:2377743
Selective Photo‐Oxygenation of Light Alkanes Using Iodine Oxides and Chloride
Journal Article
·
Tue Sep 24 20:00:00 EDT 2019
· ChemCatChem
·
OSTI ID:1571528