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Standard reactions for comparative rate studies: Experiments on the dehydrochlorination reactions of 2‐chloropropane, chlorocyclopentane, and chlorocyclohexane
Author(s) -
Awan Iftikhar A.,
Burgess Jr. Donald R.,
Tsang Wing,
Manion Jeffrey A.
Publication year - 2012
Publication title -
international journal of chemical kinetics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.341
H-Index - 68
eISSN - 1097-4601
pISSN - 0538-8066
DOI - 10.1002/kin.20566
Subject(s) - chemistry , cyclohexene , bar (unit) , reaction rate constant , propene , shock tube , thermodynamics , cyclopentene , rrkm theory , computational chemistry , analytical chemistry (journal) , kinetics , organic chemistry , shock wave , catalysis , physics , quantum mechanics , meteorology
Single pulse shock tube studies of the thermal dehydrochlorination reactions (chlorocyclopentane → cyclopentene + HCl) and (chlorocyclohexane → cyclohexene + HCl) at temperatures of 843–1021 K and pressures of 1.4–2.4 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) = 1.4 × 10 15 exp(−33,500/ 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 the literature data from lower temperature static studies leads to k (2‐chloropropane) = 10 (13.98±0.08) exp(−26, 225 ± 130) K/ T ) s −1 ; 590–1020 K; 1–3 bark (chlorocylopentane) = 10 (13.65 ± 0.10) exp(−24,570 ± 160) K/T) s −1 ; 590–1020 K; 1–3 bark (chlorocylohexane) = 10 (14.33 ± 0.10) exp(−25,950 ± 180) K/T) s −1 ; 590–1020 K; 1–3 bar Including systematic uncertainties, expanded standard uncertainties are estimated to be about 15% near 600 K rising to about 25% at 1000 K. At 2 bar and 1000 K, the reactions are only slightly under their high‐pressure limits, but falloff effects rapidly become significant at higher temperatures. On the basis of computational studies and Rice–Ramsperger–Kassel–Marcus (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: k ∞ (2‐chloropropane) = 5.74 × 10 9 T 1.37 exp(−25,680/T) s −1 ; 600–1600 Kk ∞ (chlorocylopentane) = 7.65 × 10 7 T 1.75 exp(−23,320/T) s −1 ; 600–1600 Kk ∞ (chlorocylohexane) = 8.25 × 10 9 T 1.34 exp(−25,010/T) s −1 ; 600–1600 K © 2011 Wiley Periodicals, Inc. * This article is a U.S. Government work and, as such, is in the public domain of the United States of America. Int J Chem Kinet 44: 351–368, 2012