The Role of Radicals in the Conversion of Trifluoromethane in the Flame of Methane–Oxygen Mixtures

The mechanism of CF3H transformation in the flame of methane–oxygen mixtures of various compositions was calculated from the available experimental data on the concentrations of intermediates, taking into account only those elementary reactions whose kinetic parameters are known. In the flame of a CH4/O2 mixture, CF3H is destroyed in reactions with H, O, and OH without being regenerated, which disproves the classical (and still existing) ideas about the molecular mechanism of the transformation of initial reagents in the flame. In a rich mixture, the transformation mainly proceeds due to the reactions of CF3H, CF3, СF2, and COF2 with atomic hydrogen, competing with the stage of branching of the reaction chains that inhibit the combustion of methane in oxygen. In a stoichiometric and especially in a lean mixture, the role of oxidative processes involving O and OH increases, and the inhibition effect weakens. The resulting scheme qualitatively describes the entire known experimental picture observed during the combustion of CH4/O2/CF3H mixtures.