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. 2023 May 3;8(19):16859-16868.
doi: 10.1021/acsomega.3c00491. eCollection 2023 May 16.

Mechanistic and Kinetic Approach on the Propargyl Radical (C3H3) with the Criegee Intermediate (CH2OO)

Tien V Pham  1 , Hoang T T Trang  2
Affiliations

Mechanistic and Kinetic Approach on the Propargyl Radical (C3H3) with the Criegee Intermediate (CH2OO)

Tien V Pham et al. ACS Omega. .

Abstract

The detailed reaction mechanism and kinetics of the C3H3 + CH2OO 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 C3H3 + CH2OO system. The C3H3 + CH2OO reaction leading to the CH2-[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 C3H3 + CH2OO → CH2-[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 C3H3 + CH2OO → CHCCH2CHO + OH, C3H3 + CH2OO → OCHCHCHCHO + H, and C3H3 + CH2OO → CHCHCHO + CH2O fluctuate with temperatures. The branching ratio of the C3H3 + CH2OO → CH2-[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 + CH2O) 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 CH2OO-related systems under atmospheric and combustion conditions.

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Conflict of interest statement

The authors declare no competing financial interest.

Figures

Figure 1
Figure 1
Simplified potential energy surface for the C3H3 + CH2O2 reaction leading to various products. Energies (in units of kcal/mol) calculated at the CBS-QB3 level.
Figure 2
Figure 2
Plot of rate constants of the C3H3 + CH2OO system calculated at P = 1 Torr (Ar) in the temperature range of 300–2000 K.
Figure 3
Figure 3
Plot of rate constants of the C3H3 + CH2OO system calculated at P = 7.6 Torr (Ar) in the temperature range of 300–2000 K.
Figure 4
Figure 4
Plot of rate constants of the C3H3 + CH2OO system calculated at P = 76 Torr (Ar) in the temperature range of 300–2000 K.
Figure 5
Figure 5
Plot of rate constants of the C3H3 + CH2OO system calculated at P = 760 Torr (Ar) in the temperature range of 300–2000 K.
Figure 6
Figure 6
Plot of rate constants of the C3H3 + CH2OO system calculated at P = 7600 Torr (Ar) in the temperature range of 300–2000 K.
Figure 7
Figure 7
Plot of rate constants of the C3H3 + CH2OO system calculated at P = 76,000 Torr (Ar) in the temperature range of 300–2000 K.
Figure 8
Figure 8
Branching ratios of the C3H3 + CH2OO system calculated at P = 760 Torr (Ar) in the temperature range of 300–2000 K.
See this image and copyright information in PMC

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