C-C bond fission pathways of chloroalkenyl alkoxy radicals Academic Article uri icon

abstract

  • Density-functional theory and ab initio molecular orbital calculations have been employed to determine the structures and energetics of the chloroalkenyl alkoxy radicals arising from Cl-initiated reactions of isoprene as well as the transition states and products of their decomposition reactions. Geometry optimizations of the various species were performed at the Becke three parameter LeeYangParr (B3LYP)/6-31G(d,p) level, and single-point energies were computed using second-order MllerPlesset and coupled-cluster theory with single and double excitations including perturbative corrections for the triple excitations. The activation and reaction energies of CC bond scission of the alkoxy radicals are in the ranges of 1225 and 322kcalmol1, respectively. Using the obtained activation barriers and transition state structures, we have calculated the high-pressure limit decomposition rates of the chloroalkenyl alkoxy radicals using transition state theory, ranging from 1105 to 2104s1. The results indicate that CC bond decomposition of the chloroalkenyl alkoxy radicals is rather slow and likely plays a minor role in the Cl-isoprene reactions. Implications of the present results on the formation yields of methyl vinyl ketone, methacrolein, and 1-chloro-3-methyl-3-buten-2-one are discussed.

published proceedings

  • JOURNAL OF CHEMICAL PHYSICS

author list (cited authors)

  • Zhang, D., Zhang, R. Y., & Allen, D. T.

citation count

  • 11

complete list of authors

  • Zhang, D||Zhang, RY||Allen, DT

publication date

  • January 2003