The mechanism and rate constants for oxidation of indenyl radical C9H7 with molecular oxygen O2: a theoretical study
| Autor: | Valeriy N. Azyazov, A. R. Ghildina, A. M. Mebel, D. P. Porfiriev |
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| Rok vydání: | 2019 |
| Předmět: |
010304 chemical physics
Branching fraction Chemistry Radical Ab initio General Physics and Astronomy 02 engineering and technology 021001 nanoscience & nanotechnology Branching (polymer chemistry) 01 natural sciences Reaction rate Reaction rate constant 0103 physical sciences Potential energy surface Physical chemistry Molecular oxygen Physical and Theoretical Chemistry 0210 nano-technology |
| Zdroj: | Physical Chemistry Chemical Physics. 21:8915-8924 |
| ISSN: | 1463-9084 1463-9076 |
| DOI: | 10.1039/c9cp01122f |
| Popis: | Ab initio G3(MP2,CC)//B3LYP/6-311G(d,p) calculations have been carried out to map out the C9H7O2 potential energy surface in relation to the reaction of the 1-indenyl radical with molecular oxygen. The resulting energetics and molecular parameters of the species involved in the reaction have been then utilized in Rice–Ramsperger–Kassel–Marcus master equation calculations of temperature- and pressure-dependent reaction rate constants and product branching ratios. The results demonstrate that, while the reaction is insignificant at low temperatures, at higher temperatures, above 800 K or higher depending on the pressure, the prevailing reaction channel leads to the formation of the 1-H-inden-1-one + OH products via a 1,3-H shift from C to O in the initial association complex W1 accompanied by OH elimination through a high barrier of 25.6 kcal mol−1. The branching ratio of 1-H-inden-1-one + OH increases from ∼61% to ∼80% with temperature, whereas c-C6H4-CH2CHO + CO (32–12%) and coumarin + H (7–6%) are significant minor products. The total rate constant of the indenyl + O2 reaction leading to the bimolecular products is independent of pressure and exceeds 1.0 × 10−15 cm3 molecule−1 s−1 only at temperatures above 2000 K, reaching 6.7 × 10−15 cm3 molecule−1 s−1 at 2500 K. The indenyl + O2 reaction is concluded to be too slow to play a substantial role in oxidation of the five-member ring in indenyl and the present results corroborate the assertion that molecular oxygen is not an efficient oxidizer of five-member-ring radicals. |
| Databáze: | OpenAIRE |
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