Mechanistic and Kinetic Approach on the Propargyl Radical (C(3)H(3)) with the Criegee Intermediate (CH(2)OO)

[Image: see text] The detailed reaction mechanism and kinetics of the C(3)H(3) + CH(2)OO system have been thoroughly investigated. The CBS-QB3 method in conjunction with the ME/vRRKM theory has been applied to figure out the potential energy surface and rate constants for the C(3)H(3) + CH(2)OO system. The C(3)H(3) + CH(2)OO reaction leading to the CH(2)-[cyc-CCHCHOO] + H product dominates compared to the others. Rate constants of the reaction are dependent on temperatures (300–2000 K) and pressures (1–76,000 Torr), for which the rate constant of the channel C(3)H(3) + CH(2)OO → CH(2)-[cyc-CCHCHOO] + H decreases at low pressures (1–76 Torr), but it increases with rising temperature if the pressure P ≥ 760 Torr. Rate constants of the three reaction channels C(3)H(3) + CH(2)OO → CHCCH(2)CHO + OH, C(3)H(3) + CH(2)OO → OCHCHCHCHO + H, and C(3)H(3) + CH(2)OO → CHCHCHO + CH(2)O fluctuate with temperatures. The branching ratio of the C(3)H(3) + CH(2)OO → CH(2)-[cyc-CCHCHOO] + H channel is the highest, accounting for 51–98.7% in the temperature range of 300–2000 K and 760 Torr pressure, while those of the channels forming the products PR10 (OCHCHCHCHO + H) and PR11 (CHCHCHO + CH(2)O) are the lowest, less than 0.1%, indicating that the contribution of these two reaction paths to the title reaction is insignificant. The proposed temperature- and pressure-dependent rate constants, together with the thermodynamic data of the species involved, can be confidently used for modeling CH(2)OO-related systems under atmospheric and combustion conditions.