Thermochemistry and Kinetics of the Thermal Decomposition of 1‐Chlorohexane

A theoretical kinetic study of the thermal decomposition of 1‐chlorohexane in gas phase between 600 and 1000 K was performed. Transition‐state theory and unimolecular reaction rate theory were combined with molecular information provided by quantum chemical calculations. Particularly, the B3LYP, BMK, M05–2X, and M06–2X formulations of the density functional theory (DFT) and the high‐level ab initio methods G3B3 and G4 were employed. The possible reaction channels for the thermal decomposition of 1‐chlorohexane were investigated, and the reaction takes place through the elimination of HCl with the formation of 1‐hexene. The derived high‐pressure limit rate coefficients are k _∞(600–1000 K) = (8 ± 5) × 10¹³ exp[‐((56.7 ± 0.4) kcal mol⁻¹/RT )] s⁻¹. The pressure effect over the reaction was analyzed from the calculation of the low‐pressure limit rate coefficients and the falloff curves. In addition, the standard enthalpies of formation at 298 K of −46.9 ± 1.5 kcal mol⁻¹ for 1‐chlorohexane and 5.8 ± 1.5 kcal mol⁻¹ for C₆H₁₃ radical were derived from isodesmic and isogiric reactions at high levels of theory.