A theoretical study of the CH₃H-C₂H₂ reaction

The rate constants for the formation of various products in the CH ₃+C₂H₂ reaction have been computed by multichannel RRKM calculations using the molecular and transition-state parameters predicted by the BAC-MP4 method. The results of the calculations agree quantitatively with experimental data obtained under varying conditions: T=300-2200 K, P=30-2500 Torr. At low temperatures (T<1300 K), the CH ₃+C₂H₂ reaction is dominated by the addition-stabilization process producing CH₃C₂H ₂. Under high-temperature (7>1400 K) and atmospheric-pressure conditions, the reaction occurs primarily by the CH₃-for-H displacement process producing CH₃C₂H, a likely source of the C₃H₃ radical (which has recently been shown to be a key precursor of C₆H₆ in hydrocarbon combustion reactions).