Quantum Chemical and Kinetics Study of the Thermal Gas Phase Decomposition of 2-Chloropropene

Abstract

A detailed theoretical study of the kinetics of the thermal decomposition of 2-chloropropene over the 600–1400 K temperature range has been done. The reaction takes place through the elimination of HCl with the concomitant formation of propyne or allene products. Relevant molecular properties of the reactant and transition states were calculated for each reaction channel at 14 levels of theory. From information provided by the BMK, MPWB1K, BB1K, M05-2X, and M06-2X functionals, specific for chemical kinetics studies, high-pressure limit rate coefficients of (5.8 ± 1.0) × 1014 exp[−(67.8 ± 0.4 kcal mol–1)/RT] s–1 and (1.1 ± 0.2) × 1014 exp[−(66.8 ± 0.5 kcal mol–1)/RT] s–1 were obtained for the propyne and allene channels, respectively. The pressure effect over the reaction was analyzed through the calculation of the low-pressure limit rate coefficients and falloff curves. An analysis of the branching ratio between the two channels as a function of pressure and temperature, based on these results and on computed specific rate coefficients, show that the propyne forming channel is predominant.