## Abstract

The kinetics of C_{6}H_{5} reactions with n-C_{n}H_{2n+2} (n = 3, 4, 6, 8) have been studied by the pulsed laser photolysis/mass spectrometric method using C_{6}H_{5}COCH_{3} as the phenyl precursor at temperatures between 494 and 1051 K. The rate constants were determined by kinetic modeling of the absolute yields of C_{6}H_{6} at each temperature. Another major product C_{6}H_{5}CH_{3} formed by the recombination of C_{6}H_{5} and CH_{3} could also be quantitatively modeled using the known rate constant for the reaction. A weighted least-squares analysis of the four sets of data gave k (C_{3}H_{8}) = (1.96 ± 0.15) × 10^{11} exp[-(1938 ± 56)/T], and k (n-C_{4}H_{10}) = (2.65 ± 0.23) × 10^{11} exp[-(1950 ± 55)/T], k (n-C_{6}H_{14}) = (4.56 ± 0.21) × 10^{11} exp[-(1735 ± 55)/T], and k (n-C_{8}H_{18}) = (4.31 ± 0.39) × 10^{11} exp[-(1415 ± 65)/T] cm^{3} mol^{-1} s^{-1} for the temperature range studied. For the butane and hexane reactions, we have also applied the CRDS technique to extend our temperature range down to 297 K; the results obtained by the decay of C_{6}H_{5} with CRDS agree fully with those determined by absolute product yield measurements with PLP/MS. Weighted least-squares analyses of these two sets of data gave rise to k (n-C_{4}H_{10}) = (2.70 ± 0.15) × 10^{11} exp[-(1880 ± 127)/T] and k (n-C_{6}H_{14}) = (4.81 ± 0.30) × 10^{11} exp[-(1780 ± 133)/T] cm^{3} mol^{-1} s^{-1} for the temperature range 297-1046 K. From the absolute rate constants for the two larger molecular reactions (C_{6}H_{5} + n-C_{6}H_{14} and n-C_{8}H_{18}), we derived the rate constant for H-abstraction from a secondary C-H bond, k_{s-CH} = (4.19 ± 0.24) × 10^{10} exp[-(1770 ± 48)/T] cm^{3} mol^{-1} s^{-1}.

Original language | English |
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Pages (from-to) | 49-56 |

Number of pages | 8 |

Journal | International Journal of Chemical Kinetics |

Volume | 36 |

Issue number | 1 |

DOIs | |

State | Published - 1 Jan 2004 |