Theoretical and kinetic modeling study of chloromethane (CH₃Cl) pyrolysis and oxidation

This work presents a comprehensive kinetic modeling study of the pyrolysis and oxidation of chloromethane. Theoretical calculations were performed for the decomposition reaction CH₃Cl + M = CH₃ + Cl + M and for a set of relevant H‐abstraction reactions (CH₃Cl + R, R = Cl, Ḣ, ȮH, HȮ₂, O2, Ö, ĊH₃, Ċ2H3, Ċ₂H₅; CH₄ + Cl, C₂H₆ + Cl, C₂H₄ + Cl, C₂H₂ + Cl). Comparison with previous experimental or theoretical determinations, when available, proved the appropriateness of the adopted protocols and the accuracy of the calculated rate constants. Previously developed subsets for CH₃Cl and HCl/Cl₂ were updated with the theoretical rate constants and combined with the CRECK C₁–C₃ mechanism, yielding a kinetic mechanism consisting of 143 species and 2347 reactions. The validation was performed through comparison with all the pyrolysis and oxidation measurements available for pure CH₃Cl and its mixtures with CH₄, H₂, and CO/H₂O. The kinetic discussion highlights the role of key reaction steps that have been theoretically investigated in this work and in previous efforts and sheds light on additional reaction pathways needing better assessments.