Gas-phase reaction of halon 1301 (CBrF3) with methane

Nonoxidative gas-phase reaction of halon 1301 (CBrF3) with methane in a nitrogen bath was investigated using a tubular plug flow reactor. Experiments were performed at atmospheric pressure, over a range of temperatures (673-1053 K) and residence times.(0.1-2.0 s). Compared to the thermal decomposition of CBrF3, the addition of CH4 to the reacting stream results in a substantial increase in the conversion of CBrF3, with conversion levels rising with increasing content of CH4. Generally, the conversion of both reactants increases with temperature or residence time. At high temperatures and an equal-molar CBrF3/CH4 feed stream, the proportion of CBrF3 converted is always greater than that of CH4. In addition to HBr and HF, the major products of the reaction were CHF3, CH3Br, and C2H2F2, while minor products include C2H4, C2H2, C2H3Br, CHBrF2, C2F6, C2H3F3, C2HBrF2, C2H3F, C2HF5, C6H5F, C6H5BrF, CH2Br2, and Hz Coke formation was observed above 960 K. A reaction mechanism for prediction of major and important minor species is presented and discussed. The reaction kinetics can be represented (at low conversion) by a second-order global reaction scheme with the following rate parameters: k(global) = 3.41 x 10(15) (cm(3).mol(-1).s(-1)) exp(-180.2 (kJ.mol(-1))/RT).