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•Detailed kinetic mechanism of the OH-initiated oxidation of cyclopentadiene is computationally reported for T = 298 – 2000 K &P = 0.76 – 7600 Torr.•Kinetic discrepancies among literature data are resolved.•Reaction mechanism shift is observed with the dominance of OH-addition and H-abstraction channels at low and high temperatures, respectively.•U-shaped T-dependence and weakly positive P-dependence at low temperatures of the rate constants are observed.
This work computationally reports a detailed kinetic mechanism of the OH-initiated reaction of 1,3-cyclopentadiene (CPDN), a key intermediate during the oxidation processes of aromatic and acyclic compounds, in the wide range of T = 298 – 2000 K and P = 0.76 – 7600 Torr. The temperature- and pressure-dependent behaviors of the title reaction were simulated using the RRKM-based Master Equation rate model on the potential energy profile explored at M06-2X/aug-cc-pVTZ level. The model reveals that the OH-addition on Cα of CPDN to form adduct 5-hydroxycyclopent-2-en-1-yl dominates at low temperatures (e.g., T ≤ 1000 K at 760 Torr), while the direct H-abstraction channels from Cα and Cβ of CPDN become predominant at high temperatures (e.g., T > 1000 K at 760 Torr). The observed U-shaped temperature-dependent behaviors and slightly positive pressure dependence at low temperatures (e.g., T ≤ 1000 K &P = 760 Torr) of the total rate constants are described by a double modified Arrhenius expression as ktot(T) = 1.61 × 109 × T−6.67 × exp[-1627.6 K/T] + 3.87 × 10-17 × T2.08 × exp[-2519.9 K/T] (cm3/molecule/s) for T = 298 – 2000 K &P = 760 Torr. Discrepancies in ktotal(T, P) between the early calculations and measurements in low- and high-temperature regimes are also resolved. Also, the thermodynamically consistent mechanism is provided to advance modeling and simulation of any CPDN-related applications.