Direct investigations on the thermal unimolecular isomerization reaction of 1-pentyl radicals

Miyoshi, Akira; Widjaja, Jemmy; Yamauchi, Noboru; Koshi, Mitsuo; Matsui, Hiroyuki

doi:10.1016/s1540-7489(02)80158-4

Cited by 20 publications

(51 citation statements)

References 33 publications

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“…Unlike the threeor four-member ring isomerization that has an energy barrier close or higher than the C−C or C−H bond cleavage process [19,20], the lower energy barrier of the 1,4 H-atom shift isomerization in 1-pentyl would be an important competing channel with the decomposition reactions. Jitariu et al's theoretical calculation of the 1,4 H-atom shift isomerization in the 1-pentyl radical [21] confirmed the result from Miyoshi et al [10]. FIG.…”

Section: Introductionsupporting

confidence: 55%

“…The dissociation and isomerization reactions of the 1pentyl radical on the electronic ground state have been studied for decades experimentally [3−12] and theoretically [11, 13−18]. The allylic C−C bond cleavage to yield ethene (C 2 H 4 ) and n-propyl radical (n-C 3 H 7 ) product would be the main dissociation channel in the thermal decomposition of the 1-pentyl because of the low bond energy and dissociation energy barrier, and the n-propyl radical could further decompose to the ethene and methyl radical products [9,10]. Miyoshi et al observed isomerization of the 1-pentyl radical to the 2-pentyl radical via a 1,4 H-atom shift with a fivemember ring transition state firstly, and in their Rice-Ramsperger-Kassel-Marcus (RRKM)/master-equation analyses estimated an energy barrier of this fivemember ring isomerization lower than that of the C−C or C−H bond fission of 1-pentyl [10].…”

Section: Introductionmentioning

confidence: 99%

“…The allylic C−C bond cleavage to yield ethene (C 2 H 4 ) and n-propyl radical (n-C 3 H 7 ) product would be the main dissociation channel in the thermal decomposition of the 1-pentyl because of the low bond energy and dissociation energy barrier, and the n-propyl radical could further decompose to the ethene and methyl radical products [9,10]. Miyoshi et al observed isomerization of the 1-pentyl radical to the 2-pentyl radical via a 1,4 H-atom shift with a fivemember ring transition state firstly, and in their Rice-Ramsperger-Kassel-Marcus (RRKM)/master-equation analyses estimated an energy barrier of this fivemember ring isomerization lower than that of the C−C or C−H bond fission of 1-pentyl [10]. Unlike the threeor four-member ring isomerization that has an energy barrier close or higher than the C−C or C−H bond cleavage process [19,20], the lower energy barrier of the 1,4 H-atom shift isomerization in 1-pentyl would be an important competing channel with the decomposition reactions.…”

Section: Introductionmentioning

confidence: 99%

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Ultraviolet photodissociation dynamics of 1-pentyl radical

Sun

Song

Zhang

2018

Chinese Journal of Chemical Physics

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The ultraviolet (UV) photodissociation of jet-cooled 1-pentyl radical is investigated in the wavelength region of 236−254 nm using the high-n Rydberg-atom time-of-flight (HRTOF) technique. The H-atom photofragment yield spectrum of the 1-pentyl radical shows a broad UV absorption feature peaking near 245 nm, similar to the 2p z →3s absorption bands of ethyl and n-propyl. The center-of-mass translational energy distribution, P (E T), of the H+C 5 H 10 product channel is bimodal, with a slow peak at ∼5 kcal/mol and a fast peak at ∼50 kcal/mol. The fraction of the average translational energy release in the total available energy, ⟨f T ⟩, is 0.30, with those of the slow and fast components being 0.13 and 0.58, respectively. The slow component has an isotropic product angular distribution, while the fast component is anisotropic with an anisotropy parameter ∼0.4. The bimodal translational energy and angular distributions of the H+C 5 H 10 products indicate two H-atom elimination channels in the photodissociation of 1-pentyl: (i) a direct, prompt dissociation from the electronic excited state and/or the repulsive part of the ground electronic state potential energy surface; and (ii) a unimolecular dissociation of internally hot radical in the ground electronic state after internal conversion from the electronic excited state.

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Section: Introductionsupporting

confidence: 55%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Ultraviolet photodissociation dynamics of 1-pentyl radical

Sun

Song

Zhang

2018

Chinese Journal of Chemical Physics

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“…The 1,4-hydrogen shift isomerization reaction of 1-pentyl radical is a prototype for an important class of reaction in the combustion of hydrocarbons. Alkyl isomerization reactions have been investigated both experimentally [1][2][3] and computationally. 4 The first direct measurement of the 1,4-hydrogen shift isomerization of 1-pentyl was reported in 2002 by Miyoshi et al 2 Hydrogen shift reactions are expected to be dominated by tunneling contributions at 500 K and below.…”

Section: Introductionmentioning

confidence: 99%

Multi-structural variational transition state theory. Kinetics of the 1,4-hydrogen shift isomerization of the pentyl radical with torsional anharmonicity

2011

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“…Hydrocarbon radicals play important roles in combustion reactions. Their unimolecular decomposition has therefore been widely studied . In this study, we at first applied the present f ‐RCMC method to C 3 H 5 .…”

Section: Resultsmentioning

confidence: 99%

Full rate constant matrix contraction method for obtaining branching ratio of unimolecular decomposition

2016

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The branching ratio of unimolecular decomposition can be evaluated by solving the rate equations. Recent advances in automated reaction path search methods have enabled efficient construction of the rate equations based on quantum chemical calculations. However, it is still difficult to solve the rate equations composed of hundreds or more elementary steps. This problem is especially serious when elementary steps that occur in highly different timescales coexist. In this article, we introduce an efficient approach to obtain the branching ratio from a given set of rate equations. It has been derived from a recently proposed rate constant matrix contraction (RCMC) method, and termed full-RCMC (f-RCMC). The f-RCMC gives the branching ratio without solving the rate equations. Its performance was tested numerically for unimolecular decomposition of C H and C H . Branching ratios obtained by the f-RCMC precisely reproduced the values obtained by numerically solving the rate equations. It took about 95 h to solve the rate equations of C H consisting of 234 elementary steps. In contrast, the f-RCMC gave the branching ratio in less than 1 s. The f-RCMC would thus be an efficient alternative of the conventional kinetic simulation approach. © 2016 Wiley Periodicals, Inc.

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Direct investigations on the thermal unimolecular isomerization reaction of 1-pentyl radicals

Cited by 20 publications

References 33 publications

Ultraviolet photodissociation dynamics of 1-pentyl radical

Ultraviolet photodissociation dynamics of 1-pentyl radical

Multi-structural variational transition state theory. Kinetics of the 1,4-hydrogen shift isomerization of the pentyl radical with torsional anharmonicity

Full rate constant matrix contraction method for obtaining branching ratio of unimolecular decomposition

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