Effect of ammonia and formic acid on the CH<sub>3</sub>O˙ + O<sub>2</sub> reaction: a quantum chemical investigation

Kumar, Amit; Mallick, Subhasish; Mishra, Brijesh Kumar; Kumar, Pradeep

doi:10.1039/c9cp04612g

Cited by 18 publications

(31 citation statements)

References 43 publications

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“…The calculated rate coefficients are nearly same even after the adjustment of the (see Fig. 10 ) and show negative temperature-dependent, such behavior has also been observed for similar reactions system in the literature 7 , 8 . The rate coefficient at different NH 3 concentration is shown in Fig.…”

Section: Resultssupporting

confidence: 81%

Effect of ammonia and water molecule on OH + CH3OH reaction under tropospheric condition

Ali

Balaganesh

Al-Odail

et al. 2021

Sci Rep

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The rate coefficients for OH + CH3OH and OH + CH3OH (+ X) (X = NH3, H2O) reactions were calculated using microcanonical, and canonical variational transition state theory (CVT) between 200 and 400 K based on potential energy surface constructed using CCSD(T)//M06-2X/6-311++G(3df,3pd). The results show that OH + CH3OH is dominated by the hydrogen atoms abstraction from CH3 position in both free and ammonia/water catalyzed ones. This result is in consistent with previous experimental and theoretical studies. The calculated rate coefficient for the OH + CH3OH (8.8 × 10−13 cm3 molecule−1 s−1), for OH + CH3OH (+ NH3) [1.9 × 10−21 cm3 molecule−1 s−1] and for OH + CH3OH (+ H2O) [8.1 × 10−16 cm3 molecule−1 s−1] at 300 K. The rate coefficient is at least 8 order magnitude [for OH + CH3OH(+ NH3) reaction] and 3 orders magnitude [OH + CH3OH (+ H2O)] are smaller than free OH + CH3OH reaction. Our calculations predict that the catalytic effect of single ammonia and water molecule on OH + CH3OH reaction has no effect under tropospheric conditions because the dominated ammonia and water-assisted reaction depends on ammonia and water concentration, respectively. As a result, the total effective reaction rate coefficients are smaller. The current study provides a comprehensive example of how basic and neutral catalysts effect the most important atmospheric prototype alcohol reactions.

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Section: Resultssupporting

confidence: 81%

Effect of ammonia and water molecule on OH + CH3OH reaction under tropospheric condition

Ali

Balaganesh

Al-Odail

et al. 2021

Sci Rep

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“…Most of the theoretical studies have focused on calculating the rate constants using a high-level ab initio methods and statistical rate theory [6][7][8][9]. Ellingson et al [9] proposed the rate constants for OH + CH 4 reaction and its 12 C/ 13 C kinetic isotopes effect using harmonic, hindered, and free rotor approaches. Their calculated rate constants were in good agreement with experimentally measurement values.…”

Section: Introductionmentioning

confidence: 99%

Effect of Water and Formic Acid on ·OH + CH4 Reaction: An Ab Initio/DFT Study

Ali

Muthiah

2022

Catalysts

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In this work, we used ab initio/DFT method coupled with statistical rate theory to answer the question of whether or not formic acid (HCOOH) and water molecules can catalyze the most important atmospheric and combustion prototype reaction, i.e., ·OH (OH radical) + CH4. The potential energy surface for ·OH + CH4 and ·OH + CH4 (+X) (X = HCOOH, H2O) reactions were calculated using the combination of hybrid-density functional theory and coupled-cluster theory with Pople basis set [(CCSD(T)/ 6-311++G(3df,3pd)//M06-2X/6-311++G(3df,3pd)]. The results of this study show that the catalytic effect of HCOOH (FA) and water molecules on the ·OH +CH4 reaction has a major impact when the concentration of FA and H2O is not included. In this situation the rate constants for the CH4 + HO···HCOOH (3 × 10−9 cm3 molecule−1 s−1) reaction is ~105 times and for CH4 + H2O···HO reaction (3 × 10−14 cm3 molecule−1 s−1 at 300 K) is ~20 times higher than ·OH +CH4 (~6 × 10−15 cm3 molecule−1 s−1). However, the total effective rate constants, which include the concentration of both species in the kinetic calculation has no effect under atmospheric condition. As a result, the total effective reaction rate constants are smaller. The rate constants when taking the account of the FA and water for CH4 + HO···HCOOH (4.1 × 10−22 cm3 molecule−1 s−1) is at least seven orders magnitude and for the CH4 + H2O···HO (7.6 × 10−17 cm3 molecule−1 s−1) is two orders magnitude smaller than ·OH +CH4 reaction. These results are also consistent with previous experimental and theoretical studies on similar reaction systems. This study helps to understand how FA and water molecules change the reaction kinetic under atmospheric conditions for ·OH +CH4 reaction.

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“…In the Earth's atmosphere, • CH 3 radical is formed by the oxidation of methane by several tropospheric oxidizing agents such as OH, NO 3 radicals and the Cl atom. The kinetics of a • CH 3 + O 2 reaction have been a key topic in combustion chemistry for the last five decades [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17]. The reaction mechanism behind • CH 3 oxidation is certainly an important part of the kinetic modeling of volatile organic compounds (VOCs).…”

Section: Introductionmentioning

confidence: 99%

“…The reaction mechanism behind • CH 3 oxidation is certainly an important part of the kinetic modeling of volatile organic compounds (VOCs). Several research groups have been proposed for the oxidation mechanism for the • CH 3 + O 2 reaction, as given below [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17];…”

Section: Introductionmentioning

confidence: 99%

“…• CH 3 can also be oxidized to form an oxygen-centered methoxy radical ( • CH 3 O) and an O atom via O-O breaking (R3) [11]. Many experimental and theoretical studies on the • CH 3 ••• 3 O 2 reaction system have been performed under atmospheric and combustion conditions [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17]. Several research groups have used various experimental techniques, such as flash photolysis, gas chromatography, and molecular modulation spectrometry, to monitor the decay of reactants or products.…”

Section: Introductionmentioning

confidence: 99%

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Catalytic Effect of CO2 and H2O Molecules on •CH3 + 3O2 Reaction

2022

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The methyl (•CH3) + 3O2 radical is an important reaction in both atmospheric and combustion processes. We investigated potential energy surfaces for the effect of CO2 and H2O molecules on a •CH3+ O2 system. The mechanism for three reaction systems, i.e., for •CH3 + 3O2, •CH3 + 3O2 (+CO2) and •CH3 + 3O2 (+H2O), were explored using ab initio/DFT methods [CCSD(T)//M062X/6-311++G(3df,3pd)] in combination with a Rice−Ramsperger−Kassel−Marcus (RRKM)/master-equation (ME) simulation between a temperature range of 500 to 1500 K and a pressure range of 0.0001 to 10 atm. When a CO2 and H2O molecule is introduced in a •CH3 + 3O2 reaction, the reactive complexes, intermediates, transition states and post complexes become thermodynamically more favorable. The calculated rate constant for the •CH3 + 3O2 (3 × 10−15 cm3 molecule−1 s−1 at 1000 K) is in good agreement with the previously reported experimentally measured values (~1 × 10−15 cm3 molecule−1 s−1 at 1000 K). The rate constant for the effect of CO2 (3 × 10−16 cm3 molecule−1 s−1 at 1000 K) and H2O (2 × 10−17 cm3 molecule−1 s−1 at 1000 K) is at least one–two-order magnitude smaller than the free reaction (3 × 10−15 cm3 molecule−1 s−1 at 1000 K). The effect of CO2 and H2O on •CH3 + 3O2 shows non-RRKM behavior, however, the effect on •CH3 + 3O2 shows RRKM behavior. Our results also demonstrate that a single CO2 and H2O molecule has the potential to accelerate a gas-phase reaction at temperature higher than >1300 K and slow the reaction at a lower temperature. The result is unique and observed for the first time.

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Effect of ammonia and formic acid on the CH₃O˙ + O₂ reaction: a quantum chemical investigation

Abstract: In the present work, the catalytic effect of ammonia and formic acid on the CH3O˙ + O2 reaction has been investigated employing the MN15L density functional.

Cited by 18 publications

References 43 publications

Effect of ammonia and water molecule on OH + CH3OH reaction under tropospheric condition

Effect of ammonia and water molecule on OH + CH3OH reaction under tropospheric condition

Effect of Water and Formic Acid on ·OH + CH4 Reaction: An Ab Initio/DFT Study

Catalytic Effect of CO2 and H2O Molecules on •CH3 + 3O2 Reaction

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Effect of ammonia and formic acid on the CH3O˙ + O2 reaction: a quantum chemical investigation

Abstract: In the present work, the catalytic effect of ammonia and formic acid on the CH3O˙ + O2 reaction has been investigated employing the MN15L density functional.

Cited by 18 publications

References 43 publications

Effect of ammonia and water molecule on OH + CH3OH reaction under tropospheric condition

Effect of ammonia and water molecule on OH + CH3OH reaction under tropospheric condition

Effect of Water and Formic Acid on ·OH + CH4 Reaction: An Ab Initio/DFT Study

Catalytic Effect of CO2 and H2O Molecules on •CH3 + 3O2 Reaction

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Effect of ammonia and formic acid on the CH₃O˙ + O₂ reaction: a quantum chemical investigation