### Abstract

The decomposition rate of benzylamine (C_{6}H_{5}CH_{2}NH_{2}) and the heat of formation of the benzyl radical (C_{6}H_{5}-CH_{2}) were determined in shock tube experiments combined with RRKM calculations. To obtain the decomposition rate of benzylamine, the NH_{2} mole fraction was measured using frequency-modulation absorption spectroscopy behind reflected shock waves. The initial slope of the NH_{2} concentration is directly proportional to the decomposition rate and the initial concentration of benzylamine. The rate expression for the decomposition reaction for the temperature range 1225-1599 K and the pressure range 1.19-1.47 bar is k_{1} = (5.49 × 10^{14})e^{-33110/[T(K)]} s^{-1} with an uncertainty of ±15%. To obtain the high-pressure-limit rate expression for benzylamine decomposition we performed RRKM calculations using the parameters obtained from the experimental data of this study and those of the VLPP study of Golden et al.^{4} The resulting high-pressure-limit rate for the temperature range 1000-1600 K is k_{∞} = (1.07 × 10^{16.0})e^{-36470/[T(K)]} s^{-1}. From the RRKM calculations, we determined the C-N bond dissociation energy of benzylamine at 0 K to be 305 ± 4 kJ mol^{-1}, and with this value and the thermochemical properties of benzylamine and NH_{2}, the heat of formation of the benzyl radical was calculated. The heat of formation of benzyl radical at 298 K is 210 ± 5 kJ mol^{-1}, which agrees with the result of Ellison et al.^{5} and the value recommended by Tsang^{6}.

Original language | English |
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Pages (from-to) | 6094-6098 |

Number of pages | 5 |

Journal | Journal of Physical Chemistry A |

Volume | 106 |

Issue number | 25 |

DOIs | |

Publication status | Published - 2002 Jun 27 |

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### All Science Journal Classification (ASJC) codes

- Physical and Theoretical Chemistry

### Cite this

*Journal of Physical Chemistry A*,

*106*(25), 6094-6098. https://doi.org/10.1021/jp020085l

}

*Journal of Physical Chemistry A*, vol. 106, no. 25, pp. 6094-6098. https://doi.org/10.1021/jp020085l

**A shock tube study of benzylamine decomposition : Overall rate coefficient and heat of formation of the benzyl radical.** / Song, Soonho; Golden, David M.; Hanson, Ronald K.; Bowman, Craig T.

Research output: Contribution to journal › Article

TY - JOUR

T1 - A shock tube study of benzylamine decomposition

T2 - Overall rate coefficient and heat of formation of the benzyl radical

AU - Song, Soonho

AU - Golden, David M.

AU - Hanson, Ronald K.

AU - Bowman, Craig T.

PY - 2002/6/27

Y1 - 2002/6/27

N2 - The decomposition rate of benzylamine (C6H5CH2NH2) and the heat of formation of the benzyl radical (C6H5-CH2) were determined in shock tube experiments combined with RRKM calculations. To obtain the decomposition rate of benzylamine, the NH2 mole fraction was measured using frequency-modulation absorption spectroscopy behind reflected shock waves. The initial slope of the NH2 concentration is directly proportional to the decomposition rate and the initial concentration of benzylamine. The rate expression for the decomposition reaction for the temperature range 1225-1599 K and the pressure range 1.19-1.47 bar is k1 = (5.49 × 1014)e-33110/[T(K)] s-1 with an uncertainty of ±15%. To obtain the high-pressure-limit rate expression for benzylamine decomposition we performed RRKM calculations using the parameters obtained from the experimental data of this study and those of the VLPP study of Golden et al.4 The resulting high-pressure-limit rate for the temperature range 1000-1600 K is k∞ = (1.07 × 1016.0)e-36470/[T(K)] s-1. From the RRKM calculations, we determined the C-N bond dissociation energy of benzylamine at 0 K to be 305 ± 4 kJ mol-1, and with this value and the thermochemical properties of benzylamine and NH2, the heat of formation of the benzyl radical was calculated. The heat of formation of benzyl radical at 298 K is 210 ± 5 kJ mol-1, which agrees with the result of Ellison et al.5 and the value recommended by Tsang6.

AB - The decomposition rate of benzylamine (C6H5CH2NH2) and the heat of formation of the benzyl radical (C6H5-CH2) were determined in shock tube experiments combined with RRKM calculations. To obtain the decomposition rate of benzylamine, the NH2 mole fraction was measured using frequency-modulation absorption spectroscopy behind reflected shock waves. The initial slope of the NH2 concentration is directly proportional to the decomposition rate and the initial concentration of benzylamine. The rate expression for the decomposition reaction for the temperature range 1225-1599 K and the pressure range 1.19-1.47 bar is k1 = (5.49 × 1014)e-33110/[T(K)] s-1 with an uncertainty of ±15%. To obtain the high-pressure-limit rate expression for benzylamine decomposition we performed RRKM calculations using the parameters obtained from the experimental data of this study and those of the VLPP study of Golden et al.4 The resulting high-pressure-limit rate for the temperature range 1000-1600 K is k∞ = (1.07 × 1016.0)e-36470/[T(K)] s-1. From the RRKM calculations, we determined the C-N bond dissociation energy of benzylamine at 0 K to be 305 ± 4 kJ mol-1, and with this value and the thermochemical properties of benzylamine and NH2, the heat of formation of the benzyl radical was calculated. The heat of formation of benzyl radical at 298 K is 210 ± 5 kJ mol-1, which agrees with the result of Ellison et al.5 and the value recommended by Tsang6.

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U2 - 10.1021/jp020085l

DO - 10.1021/jp020085l

M3 - Article

AN - SCOPUS:0037183055

VL - 106

SP - 6094

EP - 6098

JO - Journal of Physical Chemistry A

JF - Journal of Physical Chemistry A

SN - 1089-5639

IS - 25

ER -