scholarly journals Ab initio pressure-dependent reaction kinetics of methyl propanoate radicals

2015 ◽  
Vol 17 (46) ◽  
pp. 31061-31072 ◽  
Author(s):  
Ting Tan ◽  
Xueliang Yang ◽  
Yiguang Ju ◽  
Emily A. Carter
Keyword(s):  
Ab Initio ◽  
Master Equation ◽  
Reaction Kinetics ◽  
Unimolecular Dissociation ◽  
High Level ◽  
Kinetics Of ◽  
Methyl Propanoate

The unimolecular dissociation and isomerization kinetics of the three methyl propanoate (MP) radicals, CH3CH2C(O)OĊH2 (MP-m), CH3ĊHC(O)OCH3 (MP-α), and ĊH2CH2C(O)OCH3 (MP-β), are theoretically investigated using high-level ab initio methods and the Rice–Ramsperger–Kassel–Marcus (RRKM)/master equation (ME) theory.

Reaction Kinetics of CO + HO2→ Products:  Ab Initio Transition State Theory Study with Master Equation Modeling†

2007 ◽  
Vol 111 (19) ◽  
pp. 4031-4042 ◽  
Author(s):  
Xiaoqing You ◽  
Hai Wang ◽  
Elke Goos ◽  
Chih-Jen Sung ◽  
Stephen J. Klippenstein
Keyword(s):  
Transition State ◽  
Ab Initio ◽  
Master Equation ◽  
Reaction Kinetics ◽  
Transition State Theory ◽  
State Theory ◽  
Equation Modeling ◽  
Kinetics Of

Toward high-level theoretical studies on the reaction kinetics of PAHs growth based on HACA pathway: An ONIOM[G3(MP2,CC)//B3LYP:DFT] method developed

Fuel ◽  
2021 ◽  
Vol 301 ◽  
pp. 121052
Author(s):  
Chengcheng Ao ◽  
Shanshan Ruan ◽  
Wei He ◽  
Yi Liu ◽  
Chenliang He ◽  
...  
Keyword(s):  
Reaction Kinetics ◽  
Theoretical Studies ◽  
High Level ◽  
Kinetics Of

scholarly journals High-level ab initio studies of unimolecular dissociation of the ground-state N3 radical

2005 ◽  
Vol 122 (1) ◽  
pp. 014106 ◽  
Author(s):  
Peng Zhang ◽  
Keiji Morokuma ◽  
Alec M. Wodtke
Keyword(s):  
Ab Initio ◽  
Ground State ◽  
Unimolecular Dissociation ◽  
High Level

New Theoretical Insight into the Reaction Kinetics of Toluene and Hydroxyl Radicals

2020 ◽  
Author(s):  
Xiaoqing Wu ◽  
Can Huang ◽  
Shiyao Niu ◽  
Feng Zhang
Keyword(s):  
Reaction Kinetics ◽  
Quantum Chemical ◽  
Branching Ratios ◽  
Rate Coefficients ◽  
Total Rate ◽  
Barrier Heights ◽  
Reaction Channels ◽  
High Level ◽  
Kinetics Of ◽  
Insight Into

<p><a></a><a>Toluene’s removal mechanism in the atmosphere is mainly attributed to OH radical, which includes major OH-addition and minor H-abstraction reactions. The cresols and RO2 derived from OHadducts reacting to O2 have significant impacts on the generation of secondary organic aerosols (SOA) and O3. However, computed branching ratios of various OH-adducts at various theoretical levels are largely inconsistent, mainly because previously reported barrier heights of OH-addition reaction showed a strong method dependence. In the present study, we demonstrate that this reaction involves a nonnegligible anharmonic effect (during the process of OH moving to the benzene ring), which has been overlooked by previous studies. The reaction kinetics of toluene + OH was systematically studied by a high-level quantum chemical method (CCSD(T)-F12/cc-pVQZ-F12//B2PLYP-D3/6-311++G(d,p)) combined with RRKM/master equation simulations. The particle-in-a-box approximation was used to treat the anharmonicity in this system. The final total rate coefficient is calculated to be 2.60 × 10−12 cm3 molecule−1 s−1 at 300 K and 1 atm. The main products for toluene + OH are computed as ortho-adducts (50.8%), benzyl radical + H2O (21.1%), ipso-adduct (16.3%), para-adduct (6.1%), and meta-adduct (4.6%). Our results indicate that both high level quantum chemical calculations for the crucial barrier heights and appropriate treatments for the anharmonicity determine the accuracy of the final computed total rate coefficients and branching ratios. Further analysis on the branching ratios of various reaction channels provides insight into the atmosphere-initiated oxidation of toluene. </a></p>

New Theoretical Insight into the Reaction Kinetics of Toluene and Hydroxyl Radicals

2020 ◽  
Author(s):  
Xiaoqing Wu ◽  
Can Huang ◽  
Shiyao Niu ◽  
Feng Zhang
Keyword(s):  
Reaction Kinetics ◽  
Quantum Chemical ◽  
Branching Ratios ◽  
Rate Coefficients ◽  
Total Rate ◽  
Barrier Heights ◽  
Reaction Channels ◽  
High Level ◽  
Kinetics Of ◽  
Insight Into

<p><a></a><a>Toluene’s removal mechanism in the atmosphere is mainly attributed to OH radical, which includes major OH-addition and minor H-abstraction reactions. The cresols and RO2 derived from OHadducts reacting to O2 have significant impacts on the generation of secondary organic aerosols (SOA) and O3. However, computed branching ratios of various OH-adducts at various theoretical levels are largely inconsistent, mainly because previously reported barrier heights of OH-addition reaction showed a strong method dependence. In the present study, we demonstrate that this reaction involves a nonnegligible anharmonic effect (during the process of OH moving to the benzene ring), which has been overlooked by previous studies. The reaction kinetics of toluene + OH was systematically studied by a high-level quantum chemical method (CCSD(T)-F12/cc-pVQZ-F12//B2PLYP-D3/6-311++G(d,p)) combined with RRKM/master equation simulations. The particle-in-a-box approximation was used to treat the anharmonicity in this system. The final total rate coefficient is calculated to be 2.60 × 10−12 cm3 molecule−1 s−1 at 300 K and 1 atm. The main products for toluene + OH are computed as ortho-adducts (50.8%), benzyl radical + H2O (21.1%), ipso-adduct (16.3%), para-adduct (6.1%), and meta-adduct (4.6%). Our results indicate that both high level quantum chemical calculations for the crucial barrier heights and appropriate treatments for the anharmonicity determine the accuracy of the final computed total rate coefficients and branching ratios. Further analysis on the branching ratios of various reaction channels provides insight into the atmosphere-initiated oxidation of toluene. </a></p>

Ab initio calculation for isomerization reaction kinetics of nitrobenzene isomers

2019 ◽  
Vol 715 ◽  
pp. 244-251
Author(s):  
Zhongquan Gao ◽  
Meng Yang ◽  
Chenglong Tang ◽  
Feiyu Yang ◽  
Xiangshan Fan ◽  
...  
Keyword(s):  
Ab Initio ◽  
Reaction Kinetics ◽  
Ab Initio Calculation ◽  
Isomerization Reaction ◽  
Kinetics Of

Kinetics of O·− and O3·− in alkaline aqueous solutions

1997 ◽  
Vol 35 (4) ◽  
pp. 49-55 ◽  
Author(s):  
Mónica C. Gonzalez ◽  
Daniel O. Mártire
Keyword(s):  
Ab Initio ◽  
Reaction Kinetics ◽  
Computer Simulations ◽  
Reaction Mechanisms ◽  
Reaction Intermediates ◽  
Radical Ions ◽  
Decay Kinetics ◽  
First Order ◽  
Kinetics Of ◽  
Complete Interpretation

In aerated solutions containing molecular oxygen, O·− radicals effectively react with O2 yielding ozonide radical ions, O3·−. In the absence of O·− scavengers, O3·− mainly decays by unimolecular reaction yielding O·− and O2 and by further reaction with O·−. The decay rate of O3·− is therefore extremely sensitive to the presence of small quantities of ·− scavengers. In the present communication we have generated O3·− radicals by two different methods: photolysis of strong alkaline (pH &gt; 12.7) solutions of either H2O2 or S2O8=. A detailed kinetic study shows a first order decay of O3·− generated after photolysis of hydrogen peroxide, while a more complex kinetics is observed when O3·− is formed following photolysis of S2O8=. These observations indicate the involvement of different reaction mechanisms. In order to obtain a complete interpretation of the experimental data, ab-initio kinetic computer simulations were done. On one hand, the decay kinetics of O3·− generated from alkaline photolysis of H2O2 in the presence and absence of scavengers was well fitted by the ab-initio kinetic computer simulations. From the analysis of the mechanism, information on the reaction kinetics of the hydroxyl radicals with different substrates can be obtained. The possibility of retrieving information on the reaction kinetics and efficiency of these substrates as O·− and HO· scavengers, is exemplified for cyanide and carbonate ions. On the other hand, the decay kinetics of O3·− generated from alkaline photolysis of K2S2O8 can only be understood if the participation of reaction intermediates other than SO4.·−, O·− / HO·, and O2·− are considered. Alternative reaction mechanisms are discussed.

Ab initio kinetics studies of hydrogen atom abstraction from methyl propanoate

2016 ◽  
Vol 18 (6) ◽  
pp. 4594-4607 ◽  
Author(s):  
Ting Tan ◽  
Xueliang Yang ◽  
Yiguang Ju ◽  
Emily A. Carter
Keyword(s):  
Hydrogen Atom ◽  
Ab Initio ◽  
Hydrogen Abstraction ◽  
Hydrogen Atom Abstraction ◽  
Kinetics Studies ◽  
Kinetics Of ◽  
Methyl Propanoate

The kinetics of hydrogen abstraction by five radicals (H, CH3, O(3P), OH, and HO2) from a biodiesel surrogate, methyl propanoate (MP), is theoretically investigated.

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