Computational Study of the Reaction of CH2(X3B1) with CH3OH

Li, Jicun; Song, Xinli; Peng, Zhe; Hou, Hua; Wang, Baoshan

doi:10.1021/jp807598w

Cited by 6 publications

(6 citation statements)

References 29 publications

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“…Finally, we explored a pathway motivated by the result, shown in Table , that C−O bond activation in CH 2 OH has a relatively small barrier. This result led us to explore a DME formation pathway through CH 3 OCH 2 ; this is a known radical and has been shown to be a viable pathway in past . We find, however, the energy barrier for the rate limiting step of CH 3 OCH 2 formation to be quite high (1.89 eV).…”

Section: Resultsmentioning

confidence: 82%

Density Functional Studies of Methanol Decomposition on Subnanometer Pd Clusters

2009

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A density functional theory study of the decomposition of methanol on subnanometer palladium clusters (primarily Pd 4 ) is presented. Methanol dehydrogenation through C-H bond breaking to form hydroxymethyl (CH 2 OH) as the initial step, followed by steps involving formation of hydroxymethylene (CHOH), formyl (CHO), and carbon monoxide (CO), is found to be the most favorable reaction pathway. A competing dehydrogenation pathway with O-H bond breaking as the first step, followed by formation of methoxy (CH 3 O) and formaldehyde (CH 2 O), is slightly less favorable. In contrast, pathways involving C-O bond cleavage are much less energetically favorable, and no feasible pathways involving C-O bond formation to yield dimethyl ether (CH 3 OCH 3 ) are found. Comparisons of the results are made with methanol decomposition products adsorbed on more extended Pd surfaces; all reaction intermediates are found to bind slightly more strongly to the clusters than to the surfaces.

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Section: Resultsmentioning

confidence: 82%

Density Functional Studies of Methanol Decomposition on Subnanometer Pd Clusters

2009

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“…One can see that all six reaction channels involve significant barriers, so the variational effects might be negligible. 43 The conventional TST is employed. The detailed rate constants with the temperature for (R1)-(R6) are given in the Supporting Information.…”

Section: Resultsmentioning

confidence: 99%

“…So the TST can give reliable results based on little information, especially when the tunneling and variational effects are negligible. One can see that all six reaction channels involve significant barriers, so the variational effects might be negligible . The conventional TST is employed.…”

Section: Resultsmentioning

confidence: 99%

Theoretical Investigations on Removal Reactions of Ethenol by H Atom

Rao

Zeng²,

Huang³

et al. 2011

J. Phys. Chem. A

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Ethenol is a recently identified combustion intermediate. However, its chemistry remains unclear. In present work, the removal reactions of ethenol by H atom are investigated. The geometries of all species involved in the reaction are optimized at B3LYP/6-311++G(d,p), and their single point energies are extrapolated to the infinite-basis-set limit at the level CCSD(T). Energies are also calculated at G3B3, CBS-APNO, and CCSD(T)/6-311++G(3df, 2p) for comparison. A total of six elementary reactions, including four abstractions and two additions, with explicit transition states are investigated. The results show that the reactions are selective: for abstractions, the hydrogen atom, linked to the oxygen atom, is the most reactive; while for additions, the preferred carbon site is the head "CH(2)═". The rate constants are estimated in the temperature range 300-3000 K according to the conventional transition state theory with the Eckart tunneling model. The dominant channels are the two additions in the whole temperature range. The abstractions can be competitive at high temperature but still do not dominate. The calculated rate constants for the reverse reaction of (R6), syn-CH(2)═CHOH + H ↔ CH(3)·CHOH, are consistent with the available literature values. Finally, the Fukui functions are calculated to analyze the site reactivity.

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“…however, it is confirmed that difference of the magnitude of the rate parameters does not influence the evolution of [H] too much.Contribution of dehydration reaction of CH 3 OH by CH 2 may be one of the unique features of the CH 3 OH kinetic process 3. CH 2 + CH 3 OH reaction 17 was studied theoretically by Li et al26 This theoretical study suggests that the main product of reaction 17 is CH 3 + CH 3 O; this is in distinct contrast to the other dehydration reactions, eqs 11−16, 19, and 20, and the kinetic parameter fitted to this theoretical result is employed in the present model; however, the 1 CH 2 + CH 3 OH reaction, reaction 18, may dominate in the entire reactions of CH 2 + CH 3 OH at high temperature range, and the contribution of reaction 17 in the oxidation process may be minor. Although the estimated rate by Tsang 27 is much lower than that given by Li et al, the evolutions of [H] calculated by using these two rates do not show clear difference each other.…”

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confidence: 99%

Thermal Decomposition and Oxidation of CH₃OH

Lee

Matsui

et al. 2013

J. Phys. Chem. A

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Thermal decomposition of CH(3)OH diluted in Ar has been studied by monitoring H atoms behind reflected shock waves of 100 ppm CH(3)OH + Ar. The total decomposition rate k(1) for CH(3)OH + M → products obtained in this study is expressed as, ln(k(1)/cm(3) molecule(-1) s(-1)) = -(14.81 ± 1.22) - (38.86 ± 1.82) × 10(3)/T, over 1359-1644 K. The present result on k(1) is indicated to be substantially smaller than the extrapolation of the most of the previous experimental data but consistent with the published theoretical results [Faraday Discuss. 2002, 119, 191-205 and J. Phys. Chem. A 2007, 111, 3932-3950]. Oxidation of CH(3)OH has been studied also by monitoring H atoms behind shock waves of (0.35-100) ppm CH(3)OH + (100-400) ppm O(2) + Ar. For the low concentration CH(3)OH (below 10 ppm) + O(2) mixtures, the initial concentration of CH(3)OH is evaluated by comparing evolutions of H atoms in the same concentration of CH(3)OH with addition of 300 ppm H(2) diluted in Ar. The branching fraction for CH(3)OH + Ar → (1)CH(2) + H(2)O + Ar has been quantitatively evaluated from this comparative measurements with using recent experimental result on the yield of H atoms in the reaction of (1,3)CH(2) + O(2) [J. Phys. Chem. A 2012, 116, 9245-9254]; i.e., the branching fraction for the above reaction is evaluated as, φ(1a) = 0.20 ± 0.04 at T = 1880-2050 K, in the 1.3 and 3.5 ppm CH(3)OH + 100 ppm O(2) samples. An extended reaction mechanism for the pyrolysis and oxidation of CH(3)OH is constructed based on the results of the present study combined with the oxidation mechanism of natural gas [GRI-Mech 3.0]; evolution of H atoms can be predicted very well with this new reaction scheme over a wide concentration range for the pyrolysis (0.36-100 ppm CH(3)OH), and oxidation (0.36-100 ppm CH(3)OH + 100/400 ppm O(2)) of methanol.

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Computational Study of the Reaction of CH₂(X³B₁) with CH₃OH

Cited by 6 publications

References 29 publications

Density Functional Studies of Methanol Decomposition on Subnanometer Pd Clusters

Density Functional Studies of Methanol Decomposition on Subnanometer Pd Clusters

Theoretical Investigations on Removal Reactions of Ethenol by H Atom

Thermal Decomposition and Oxidation of CH₃OH

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Computational Study of the Reaction of CH2(X3B1) with CH3OH

Cited by 6 publications

References 29 publications

Density Functional Studies of Methanol Decomposition on Subnanometer Pd Clusters

Density Functional Studies of Methanol Decomposition on Subnanometer Pd Clusters

Theoretical Investigations on Removal Reactions of Ethenol by H Atom

Thermal Decomposition and Oxidation of CH3OH

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Product

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Computational Study of the Reaction of CH₂(X³B₁) with CH₃OH

Thermal Decomposition and Oxidation of CH₃OH