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Chlorination Chemistry. 2. Rate Coefficients, Reaction Mechanism, and Spectrum of the Chlorine Adduct of Allene



D B. Atkinson, Jeffrey W. Hudgens


Cavity ring-down (CRD) spectroscopy and ab initio calculations have determined the reaction rate coefficients, mechanism, and thermochemistry relevant to the addition of a chlorine atom to allene. Chlorine atoms were produced by laser photolysis at 351 nm and the addition reaction products were probed at a variable delay by CRD spectroscopy using a second laser pulse. Ab initio results indicate that the only product is the 2-chloroallyl (C3H4Cl) radical. We measured the continuum spectrum of the 2-chloroallyl radical between 238 and 252 nm and determined the absorption cross-section, ς240(C3H4Cl) = (2.5 ± 0.5) x 10-17 cm2. By fitting the C3H4Cl absorption data to complex kinetic mechanisms, rate coefficients at 298 K were found to be k(Cl + C3H4; 656 Pa, N2) = (1.61 ± 0.27) x 10-10 cm3 molec-1 s-1, k(Cl + C3H4; 670 Pa, He) = (1.34 ± 0.24) x 10-10 cm3 molec-1 s-1, and k(Cl + C3H4; 1330 Pa, He) = (1.75 ± 0.25) x 10-11 cm3 molec-1 s-1. The recombination reaction displayed no pressure dependence between 434 Pa and 1347 Pa in N2 buffer giving k(C3H4Cl + C3H4Cl) = (3.7 ± 1.0) x 10-11 cm3 molec-1 s-1. A study of the addition reaction of 2-chloroallyl radical and oxygen molecule determined ς240 (C3H4ClO2) = (3.6 ± 0.7) x 10-18 cm2 and k(O2 + C3H4Cl, 705 Pa N2) = (3.5 ± 0.5) x 10^-13^ cm3 molec-1 s-1. Quoted uncertainties denote two standard deviations and include the propagated uncertainties of absorption cross-sections.
Journal of Physical Chemistry A
No. 4


2-chloroallyl radical, 2-chloroallyl radical+O<sub>2</sub> reaction, cavity ring-down spectroscopy, Cl+ O<sub>2</sub> reaction, reaction rate coefficient, self-reaction rate coefficient


Atkinson, D. and Hudgens, J. (2000), Chlorination Chemistry. 2. Rate Coefficients, Reaction Mechanism, and Spectrum of the Chlorine Adduct of Allene, Journal of Physical Chemistry A, [online], (Accessed May 22, 2024)


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Created January 11, 2000, Updated October 12, 2021