Experimental and computational studies of the phenyl radical reaction with propyne

Igor V. Tokmakov, Joonbum Park, Ming-Chang Lin*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

22 Scopus citations


The kinetics for the gas-phase reaction of phenyl radical with propyne has been measured by cavity ring-down spectrometry (CRDS), and the mechanism and initial product branching have been elucidated with the help of quantum chemical calculations. Absolute rate constants measured by the CRDS technique can be expressed by the following Arrhenius equation: (k/cm3 mol -1 s-1): kpropyne(T=301-428 K) = (3.68 ± 0.92) × 1011 exp[-(1685±80)/T]. The experiment is unable to distinguish between the possible reactive channels, but theory indicates that phenyl radicals preferably add to the unsaturated terminal carbon atom in propyne under our experimental conditions. Theoretical kinetic calculations, employing high-level G2M(RCC, RMP2) and G3 energetic and IRCMax (RCCSD(T)//B3LYP-DFT) molecular parameters, reproduce the total experimental rate constants within a factor of three. Calculated total and branching rate constants are provided for high-T kinetic modeling. Addition reactions of phenyl to C3H4 are estimated to be less important molecular-growth pathways in high-T conditions (T > 1000 K) in comparison to the C6H5+C2H2 reaction.

Original languageEnglish
Pages (from-to)2075-2085
Number of pages11
Issue number10
StatePublished - 1 Oct 2005


  • Ab initio calculations
  • Gas-phase reactions
  • Kinetics
  • Phenyl
  • Propyne

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