A THEORETICAL-STUDY OF THE CH3+C2H2 REACTION

The rate constants for the formation of various products in the CH3+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 CH3+C2H2 reaction is dominated by the addition-stabilization process producing CH3C2H2. Under high-temperature (T>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).