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Ab initio calculations and RRKM/Master Equation modeling of chloroalkanes → alkenes + HCl reactions for use in comparative rate studies

Authors

  • Donald R. Burgess Jr.,

    1. Chemical and Biochemical Reference Data Division, National Institute of Standards and Technology, Gaithersburg, MD 20899-8380
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  • Jeffrey A. Manion

    Corresponding author
    1. Chemical and Biochemical Reference Data Division, National Institute of Standards and Technology, Gaithersburg, MD 20899-8380
    • Chemical and Biochemical Reference Data Division, National Institute of Standards and Technology, Gaithersburg, MD 20899-8380
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Abstract

This paper reports computations that were done in conjunction with an experimental study, reported in an accompanying paper, involving single pulse shock tube measurements of the thermal decomposition of 2-chloropropane, chlorocyclopentane, and chorocyclohexane. The overall aim of the combined work is to provide a well-defined, self-consistent, and reliable set of rate constants for those species over an extended temperature range for use as reference reactions in comparative rate studies. To provide additional validation of the results for the compounds of direct interest, the dehydrochlorination reactions of the related compounds chloroethane, 1-chloropropane, and 2-chlorobutane are also considered. The present work reviews and summarizes the literature information regarding the molecular properties, thermochemistry, and chemical kinetic data for the above six alkyl chlorides. Quantum chemical methods are used to compute the structure and energies of reactants, products, and transition states and the fundamental nature of these types of reaction (four-centered “semi-ion pair” transition states) is discussed. The experimental and theoretical results are compared in detail, and uncertainties are assessed. The computations are used, in conjunction with experimentally determined rate constants, to develop Rice–Ramsperger–Kassel–Marcus (RRKM)/Master Equation models and thereby allow extrapolation of the experimental data over an extended range of temperatures. © 2011 Wiley Periodicals, Inc.* Int J Chem Kinet 44: 369–385, 2012

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