Application of compound models for estimating rate constants of hydrocarbon thermal cracking reactions: The neopentyl radical β-scission reaction

In this work, neopentyl radical β-scission reaction kinetics and energetics are investigated using quantum chemical G3 and Complete Basis Set (CBS) compound models. Experimental thermodynamic and kinetic data are employed to assess the accuracy of these calculations. The CBS model proves to have good agreement with the experimental data, indicating it is a good method for studying other hydrocarbon cracking reactions involving large species. A kinetic model of the reaction with pressure and temperature effects is proposed. For P ≤ P₀, k [s^-1] = 1.44 × 10¹² × P^0.29 × exp(-13890.20/T); for P > P₀, k[s ^-1] = 1.04 × 10¹⁴ × exp(-16075.80/T), where P is in the units of kPa, T in the units of Kelvin, and P₀ = 2.54 × 10⁶ × exp(-7536.55/T). These equations can be easily applied to different reaction conditions without performing additional costly calculations.