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Standard Reactions for Comparative Rate Studies: Experiments on the Dehydrochlorination Reactions of 2 Chloropropane, Chlorocyclopentane and Chlorocyclohexane

Published

Author(s)

Iftikhar A. Awan, Donald R. Burgess Jr., Wing Tsang, Jeffrey A. Manion

Abstract

Single pulse shock tube studies of the thermal dehydrochlorination reactions (chlorocyclopentane → cyclopentene + HCl) and (chlorocyclohexane → cyclohexene + HCl) at temperatures of 843 to 1021 K and pressures of 1.4 to 2.4 bar have been carried out using the comparative rate technique. Rate constants have been measured relative to (2 chloropropane → propene + HCl) and the decyclization reactions of cyclohexene, 4-methylcyclohexene, and 4 vinylcyclohexene. Absolute rate constants have been derived using k(cyclohexene → ethene + butadiene) = 1.4x1015 exp( 33500/T) s 1. These data provide a self-consistent temperature scale of use in the comparison of chemical systems studied with different temperature standards. A combined analysis of the present results with literature data from lower temperature static studies leads to: k(2-chloropropane) = 10(13.98 ± 0.08) exp(-26225 ± 130) K/T) s 1; 590 K to 1020 K; 1 to 3 bar k(chlorocylopentane) = 10(13.65 ± 0.10) exp(-24570 ± 160) K /T) s 1; 590 K to 1020 K; 1 to 3 bar k(chlorocylohexane) = 10(14.33 ± 0.10)exp(-25950 ± 180) K/T) s 1; 590 K to 1020 K; 1 to 3 bar Taking systematic uncertainties into consideration, expanded standard uncertainties in these rate constants are estimated to be about 15% near 600 K rising to about 40% at 1000 K. At 2 bar and 1000 K the reactions are only slightly under their high pressure limits, but fall-off effects rapidly become significant at higher temperatures. On the basis of computational studies and RRKM/Master Equation modeling of these and reference dehydrochlorination reactions, reported in more detail in an accompanying article, the following high pressure limits have been derived:
Citation
International Journal of Chemical Kinetics

Keywords

2-chloropropane, chlorocyclopentane: chlorocyclohexane, kinetics, shock tube, dehydrochlorination

Citation

Awan, I. , Burgess Jr., D. , Tsang, W. and Manion, J. (2011), Standard Reactions for Comparative Rate Studies: Experiments on the Dehydrochlorination Reactions of 2 Chloropropane, Chlorocyclopentane and Chlorocyclohexane, International Journal of Chemical Kinetics, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=906900 (Accessed April 17, 2024)
Created November 22, 2011, Updated October 12, 2021