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

Published

November 23, 2011

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

Pub Type

Journals

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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 October 10, 2024)