(654f) Propane Oxidative Dehydrogenation Catalyzed By Iodine, Bromine, and Halide Salts
When combinations of iodine and bromine were studied at low temperatures (350 °C), bromine radicals abstract H and break the C-H bond in propane to form propyl radicals that subsequently react with I2, Br2, or IBr to form propyl halides, which in turn, are easy to separate from alkanes and derivatize. At higher temperatures (500 °C), both iodine and bromine activate the C-H bond in propane and methane, forming propyl halides which subsequently undergo dehydrohalogenation to form propylene. Iodine-bromine mixtures significantly increased propane halogenation and dehydrohalogenation rates, compared to iodine alone. The mechanism in the gas-phase was modeled using a microkinetic model to interpret the experimental results. Mixtures of lithium iodide, lithium bromide, and lithium hydroxide were also investigated as catalysts and chemical looping agents for propane oxidative dehydrogenation with gaseous iodine and bromine as intermediates.
1 Upham, D. C., Gordon, M. J., Metiu, H. & McFarland, E. W. Halogen-Mediated Oxidative Dehydrogenation of Propane Using Iodine or Molten Lithium Iodide. Catalysis Letters 146, 744-754, doi:10.1007/s10562-016-1701-1 (2016).