A laser flash photolysis/IR diode laser absorption study of the reaction of chlorine atoms with selected alkanes

✍ Scribed by Hai-Bo Qian; David Turton; Paul W. Seakins; Michael J. Pilling

• Publisher: John Wiley and Sons
• Year: 2002
• Tongue: English
• Weight: 223 KB
• Volume: 34
• Category: Article
• ISSN: 0538-8066
• DOI: 10.1002/kin.10025

✦ Synopsis

Abstract

A high‐resolution IR diode laser in conjunction with a Herriot multiple reflection flow‐cell has been used to directly determine the rate coefficients for simple alkanes with Cl atoms at room temperature (298 K). The following results were obtained: k(Cl + n‐butane) = (1.91 ± 0.10) × 10^−10^ cm^3^ molecule^−1^ s^−1^, k(Cl + n‐pentane) = (2.46 ± 0.12) × 10^−10^ cm^3^ molecule^−1^ s^−1^, k(Cl + iso‐pentane) = (1.94 ± 0.10) × 10^−10^ cm^3^ molecule^−1^ s^−1^, k(Cl + neopentane) = (1.01 ± 0.05) × 10^−10^ cm^3^ molecule^−1^ s^−1^, k(Cl + n‐hexane) = (3.44 ± 0.17) × 10^−10^ cm^3^ molecule^−1^ s^−1^ where the error limits are ±1σ. These values have been used in conjunction with our own previous measurements on Cl + ethane and literature values on Cl + propane and Cl + iso‐butane to generate a structure activity relationship (SAR) for Cl atom abstraction reactions based on direct measurements. The resulting best fit parameters are k~p~ = (2.61 ± 0.12) × 10^−11^ cm^3^ molecule^−1^ s^−1^, k~s~ = (8.40 ± 0.60) × 10^−11^ cm^3^ molecule^−1^ s^−1^, k~t~ = (5.90 ± 0.30) × 10^−11^ cm^3^ molecule^−1^ s^−1^, with f( CH~2~^^) = f ( CH~2~^^) = f (C) = f = 0.85 ± 0.06. Tests were carried out to investigate the potential interference from production of excited state HCl(v = 1) in the Cl + alkane reactions. There is some evidence for HCl(v = 1) production in the reaction of Cl with shape n‐hexane. © 2001 John Wiley & Sons, Inc. Int J Chem Kinet 34: 86–94, 2002