Kinetic Investigations of the Reaction of Phenyl Radicals
with Ethyl Acetate in the Gas Phase: An Experimental and Computational
Study
Koushik Mondal
B. Rajakumar
10.1021/acs.jpca.0c03872.s001
https://acs.figshare.com/articles/journal_contribution/Kinetic_Investigations_of_the_Reaction_of_Phenyl_Radicals_with_Ethyl_Acetate_in_the_Gas_Phase_An_Experimental_and_Computational_Study/12588147
Cavity
ring-down spectroscopy (CRDS) was employed to investigate
the kinetics of the reaction between phenyl radicals (C<sub>6</sub>H<sub>5</sub><sup>•</sup>) and ethyl acetate (EtOAc) in the
gas phase. Nitrosobenzene (C<sub>6</sub>H<sub>5</sub>NO) was used
as the radical precursor to generate C<sub>6</sub>H<sub>5</sub><sup>•</sup> at 248 nm, and the generated radicals were subsequently
probed at 504.8 nm. The rate coefficients were investigated experimentally
in the temperature range of 258–358 K with an interval of 20
K and at a total pressure of 55 Torr in the nitrogen atmosphere. The
obtained Arrhenius expression for the title reaction (C<sub>6</sub>H<sub>5</sub><sup>•</sup> + EtOAc) in the temperature range
of 258–358 K was <i>k</i><sub>phenyl + EtOAc</sub><sup>Expt – (258 – 358 K)</sup> = (9.33 ± 0.11) × 10<sup>–16</sup> exp[(883.7 ±
181.0)/<i>T</i>] cm<sup>3</sup> molecule<sup>–1</sup> s<sup>–1</sup>, and the rate coefficient at room temperature
(298 K) was <i>k</i><sub>phenyl + EtOAc</sub><sup>Expt – 298 K</sup> = (2.20 ± 0.12) × 10<sup>–14</sup> cm<sup>3</sup> molecule<sup>–1</sup> s<sup>–1</sup>. Negligible effects
of pressure and photolysis laser fluence were found on the experimentally
measured rate coefficients. To complement our experimental findings,
rate coefficients of the title reaction were computationally investigated
employing the canonical variational transition-state theory with small
curvature tunnelling (CVT/SCT) at the CCSD(T)/cc-pVDZ//B3LYP/6-31+G(d,p)
level of theory in the temperature range of 200–400 K. The
temperature-dependent rate coefficient in the studied temperature
range was obtained to be <i>k</i><sub>phenyl + EtOAc</sub><sup>Theory – (200 – 400 K)</sup> = (7.68 ± 0.12) × 10<sup>–17</sup> exp[(1731.6
± 216.0)/<i>T</i>] cm<sup>3</sup> molecule<sup>–1</sup> s<sup>–1</sup>, and the rate coefficient at 298 K was obtained
as <i>k</i><sub>phenyl + EtOAc</sub><sup>Theory – 298 K</sup> =
2.45 × 10<sup>–14</sup> cm<sup>3</sup> molecule<sup>–1</sup> s<sup>–1</sup>. Both the experimentally measured and computed
rate coefficients show good agreement at 298 K. A negative temperature
dependency was observed for both the experimentally measured and computed
rate coefficients. A detailed discussion of the thermochemical parameters
and branching ratios of the title reaction are also presented in this
Article.
2020-06-30 11:35:44
C 6 H 5
title reaction
rate coefficients
CRDS
photolysis laser fluence
temperature-dependent rate coefficient
temperature range
cm
CCSD
rate coefficients show
CVT
rate coefficient
298 K
phenyl
molecule
Computational Study Cavity ring-dow...
canonical variational transition-st...