A shock tube study of the reaction NH2 + CH4 → NH3 + CH3 and comparison with transition state theory

Golden, David M.; Hanson, Ronald K.; Bowman, Craig T.; Senosiain, Juan P.; Musgrave, Charles B.; Friedrichs, Gernot

doi:10.1002/kin.10131

Cited by 30 publications

(24 citation statements)

References 16 publications

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“…Later, the Wagner group 49,50 extended the database to higher temperatures (600-1000 K) by using an isothermal discharge flow reactor where NH2 were produced by the reaction of NH 3 with fluorine atoms. The use of shock tube finally enabled accessing experimental rate constants for temperatures ranging from 1600 to 2200 K, with hydrazine 51 or methylamine 52 9 for the two reactions. dotted, and dash-dotted lines denote the present theoretical predictions, the predictions of Mebel and Lin 53 , Song et al 52 and Siddique et al 54 , respectively.…”

Section: Ch4/c2h6 + Nh2mentioning

confidence: 99%

“…The use of shock tube finally enabled accessing experimental rate constants for temperatures ranging from 1600 to 2200 K, with hydrazine 51 or methylamine 52 9 for the two reactions. dotted, and dash-dotted lines denote the present theoretical predictions, the predictions of Mebel and Lin 53 , Song et al 52 and Siddique et al 54 , respectively. Symbols depict experimental data.…”

Section: Ch4/c2h6 + Nh2mentioning

confidence: 99%

“…Symbols depict experimental data. 54 (CBS-QB3), and the value in braces is from Song et al 52 . 3 Scaled harmonic vibrational frequencies in cm -1 , italic values are associated to hindered internal rotors 4 Rotational constants in cm -1…”

Section: Ch4/c2h6 + Nh2mentioning

confidence: 99%

“…Mebel and Lin53 first investigated the potential energy surface of the CH4/C2H6 + NH2 reactions based on G2M energetics. Song et al52 combined their high temperature data with QCISD(T)/6-311++G(3df,2p)//QCISD/6-311G(d,p) theoretical calculations to recommend a rate constant expression for the reaction CH4 + NH2. Recently, Siddique et al54 performed CBS-QB3 calculations to access the rate constants of a series of n-alkanes with NH2.Saddle points properties (Table8) for the two title reactions have been calculated withRCCSD[T]/CBS//M06-2x/aug-cc-pVTZ methods.…”

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confidence: 99%

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Contributions of Experimental Data Obtained in Concentrated Mixtures to Kinetic Studies: Application to Monomethylhydrazine Pyrolysis

Diévart

Catoire

2020

J. Phys. Chem. A

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Experimental, numerical and theoretical studies are performed to understand the explosive thermal decomposition of monomethylhydrazine/argon mixtures. Ignition delays of concentrated MMH/Ar mixtures (20-30%) have been measured behind a reflected shock wave around 1000 K and 1 atm.Although several detailed chemical kinetic models have predictive abilities for diluted and highly diluted mixtures, none of them showed predictive for concentrated mixtures. A new kinetic model is proposed, in which numerous rate constants and thermochemical data are reassessed based on theoretical calculations, with the purpose to determine whether,or to what extent, trends derived from diluted or highly diluted MMH/Ar mixtures can explain observations in concentrated MMH mixtures. The present kinetic model is found to predict speciation experimental profiles in diluted MMH/Ar mixtures and is a significant improvement in predicting theinduction delays of concentrated MMH/Ar mixtures.

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Section: Ch4/c2h6 + Nh2mentioning

confidence: 99%

Section: Ch4/c2h6 + Nh2mentioning

confidence: 99%

Section: Ch4/c2h6 + Nh2mentioning

confidence: 99%

mentioning

confidence: 99%

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Contributions of Experimental Data Obtained in Concentrated Mixtures to Kinetic Studies: Application to Monomethylhydrazine Pyrolysis

Diévart

Catoire

2020

J. Phys. Chem. A

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“…Proton tunneling is estimated by way of the WKB approximation. The WKB tunneling calculation has been used in describing tunneling in chemical reactions involving enolization of 2‐methylacetophenone, H shift in silacetylene and Phenylhydroxycarbene, γ H abstraction in ketones, rearrangement reactions of cyclopropylcarbenes, proton “ring walks” in benzenium ions, mercapto and selocarbenes, and NH 2 radical reactions with methane.…”

Section: Methodsmentioning

confidence: 99%

The photochemistry of the self‐healing chromophore Disperse Orange 11

Westfall

Dirk

2012

J of Physical Organic Chem

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Recent interest in the self‐healing ability of the laser dye 1‐amino‐2‐methylanthraquinone, Disperse Orange 11, has lead us to investigate the possible alternative mechanisms of action, either intramolecular proton transfer (PT) or twisted intramolecular charge transfer (TICT) formation. AMPAC semiempirical PM3 CI (all single excited configurations) potential energy surfaces searches have been conducted with either reaction mechanism. Based purely on the potential energy surface results, no state, S0, T1, or S1, seems especially likely to be kinetically favorable for PT. The T1 state is favorable thermodynamically for PT. However, the S1 state TICT reaction is both thermodynamically favorable and kinetically preferred over all PT reactions. There is also a favorable T1 TICT reaction, but much slower kinetically on the triplet surface than S1 TICT. The Wentzel–Kramers–Brillouin (WKB) method has been used to ascertain proton tunneling contributions to PT. Even with proton tunneling, S1 TICT is still more highly favored, though proton tunneling could make the T1 PT reaction competitive depending on the rate of intersystem crossing. We also examine spectroscopic properties of PT transfer and TICT reaction path entities in comparison with published experimental evidence. However, this comparison leads to ambiguous findings that suggest that electronic spectral properties alone will not fully clarify the mechanism. Overall, results suggest that the TICT mechanism is the most likely for optical damage and self‐repair for Disperse Orange 11, and might be considered for the damage and repair mechanisms for other organic solid state laser materials. Copyright © 2012 John Wiley & Sons, Ltd.

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A theoretical kinetic study of the reactions of NH₂ radicals with methanol and ethanol and their implications in kinetic modeling

Giri

Shrestha

V.‐T.

et al. 2022

Int J of Chemical Kinetics

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Amino (NH2) radicals play a central role in the pyrolysis and oxidation of ammonia. Several reports in the literature highlight the importance of the reactions of NH2 radicals with fuel in NH3‐dual‐fuel combustion. Therefore, we investigated the reactions of NH2 radicals with methanol (CH3OH) and ethanol (C2H5OH) theoretically. We explored the various reaction pathways by exploiting CCSD(T)/cc‐pV(T, Q)Z//M06‐2X/aug‐cc‐pVTZ level of theory. The reaction proceeds via complex formation at the entrance and exit channels in an overall exothermic process. We used canonical transition state theory to obtain the high‐pressure limiting rate coefficients for various channels over the temperature range of 300–2000 K. We discerned the role of various channels in the potential energy surface (PES) of NH2 + CH3OH/C2H5OH reactions. For both reactions, the hydrogen abstraction pathway at the OH‐site of alcohols plays a minor role in the entire T‐range investigated. By including the title reactions into an extensive kinetic model, we demonstrated that the reaction of NH2 radicals with alcohols plays a paramount role in accurately predicting the low‐temperature oxidation kinetics of NH3‐alcohols dual fuel systems (e.g., shortening the ignition delay time). On the contrary, these reactions have negligible importance for high‐temperature oxidation kinetics of NH3‐alcohol blends (e.g., not affecting the laminar flame speed). In addition, we calculated the rate coefficients for NH2 + CH4 = CH3 + NH3 reaction that are in excellent agreement with the experimental data.

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A shock tube study of the reaction NH₂ + CH₄ → NH₃ + CH₃ and comparison with transition state theory

Cited by 30 publications

References 16 publications

Contributions of Experimental Data Obtained in Concentrated Mixtures to Kinetic Studies: Application to Monomethylhydrazine Pyrolysis

Contributions of Experimental Data Obtained in Concentrated Mixtures to Kinetic Studies: Application to Monomethylhydrazine Pyrolysis

The photochemistry of the self‐healing chromophore Disperse Orange 11

A theoretical kinetic study of the reactions of NH₂ radicals with methanol and ethanol and their implications in kinetic modeling

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A shock tube study of the reaction NH2 + CH4 → NH3 + CH3 and comparison with transition state theory

Cited by 30 publications

References 16 publications

Contributions of Experimental Data Obtained in Concentrated Mixtures to Kinetic Studies: Application to Monomethylhydrazine Pyrolysis

Contributions of Experimental Data Obtained in Concentrated Mixtures to Kinetic Studies: Application to Monomethylhydrazine Pyrolysis

The photochemistry of the self‐healing chromophore Disperse Orange 11

A theoretical kinetic study of the reactions of NH2 radicals with methanol and ethanol and their implications in kinetic modeling

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A shock tube study of the reaction NH₂ + CH₄ → NH₃ + CH₃ and comparison with transition state theory

A theoretical kinetic study of the reactions of NH₂ radicals with methanol and ethanol and their implications in kinetic modeling