Pressure and Temperature Dependence of the Reaction of Vinyl Radical with Alkenes III: Measured Rates and Predicted Product Distributions for Vinyl + Butene
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- 作者：C. Franklin Goldsmith ; Huzeifa Ismail ; William H. Green
- 刊名：Journal of Physical Chemistry A
- 出版年：2009
- 出版时间：November 26, 2009
- 年：2009
- 卷：113
- 期：47
- 页码：13357-13371
- 全文大小：574K
- 年卷期：v.113,no.47(November 26, 2009)
- ISSN：1520-5215
文摘
This work reports experimental and theoretical first-order rate constants for the reaction of vinyl radical with C4H8 alkenes: 1-butene, 2-butene, and isobutene. The experiments are performed over a temperature range of 300 to 700 K at 100 Torr. Vinyl radicals (H2C═CH) were generated by laser photolysis of vinyl iodide (C2H3I) at 266 nm, and time-resolved absorption spectroscopy was used to probe vinyl radicals at 423.2 and 475 nm. Weighted Arrhenius fits to the experimental rate coefficients for 1-butene (k1), 2-butene (k2), and isobutene (k3) yield k1 = (1.3 ± 0.3) × 10−12 cm3 molecules−1 s−1 exp[−(2200 ± 120) K/T]; k2 = (1.7 ± 0.3) × 10−12 cm3 molecules−1 s−1 exp[−(2610 ± 120) K/T]; and k3 = (1.0 ± 0.1) × 10−12 cm3 molecules−1 s−1 exp[−(2130 ± 50) K/T], respectively. C6H11 potential energy surfaces (PESs) for each system were calculated using the G3 method. RRKM/ME simulations were performed for each system to predict pressure-dependent rate coefficients and branching fractions for the major channels. A generic rate rule for vinyl addition to various alkenes is recommended; a similar rate rule for the abstraction of H atoms by vinyl from alkenes is also provided. Some of the vinyl addition reactions exhibit anomalous Evans−Polanyi plots similar to those reported for previous methyl addition reactions.