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Ma Y, Fu Z, Guo HT, Liu M, Tao Z, Zhou CW. Theoretical and kinetic study of the H-atom abstraction reactions by Ḣ atom from alkyl cyclohexanes. Phys Chem Chem Phys 2024; 26:17631-17644. [PMID: 38864351 DOI: 10.1039/d4cp01117a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2024]
Abstract
Reaction kinetics of hydrogen atom abstraction from six alkyl cyclohexanes, methyl cyclohexane (MCH), ethyl cyclohexane (ECH), n-propyl cyclohexane (nPCH), iso-propyl cyclohexane (iPCH), sec-butyl cyclohexane (sBCH) and iso-butyl cyclohexane (iBCH), by the Ḣ atom are systematically studied in this work. The M06-2X method combined with the 6-311++G(d,p) basis set is used to perform geometry optimization, frequency analysis and zero-point energy calculations for all species. The intrinsic reaction coordinate (IRC) calculations are performed to confirm the transition states connecting the reactants and products correctly. One-dimensional hindered rotors are used to treat the low frequency torsional models with potentials scanned at the M06-2X/6-31G level of theory. Electronic single-point energy calculations for all reactants, transition states, and products are performed at the QCISD(T)/CBS level of theory. High-pressure limiting rate constants of 39 reaction channels are obtained using conventional transition state theory with asymmetric Eckart tunneling corrections in the temperature range 298.15-2000 K. Reaction rate rules for H-atom abstraction by the Ḣ atom from alkyl cyclohexanes on primary, secondary and tertiary carbon sites on both the side chain and ring are provided. The obtained rate constants are given by the Arrhenius expression in the temperature range 500-2000 K, which can be used for the combustion kinetics model development for alkyl cyclohexanes.
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Affiliation(s)
- Yang Ma
- School of Energy and Power Engineering, Beihang University, Beijing 100191, PR China.
| | - Zhaolin Fu
- Sinopec Research Institute of Petroleum Processing Co., Ltd., 18 Xueyuan Road, Haidian District, Beijing 100083, PR China
| | - Hao-Ting Guo
- School of Energy and Power Engineering, Beihang University, Beijing 100191, PR China.
| | - Mingxia Liu
- School of Energy and Power Engineering, Beihang University, Beijing 100191, PR China.
| | - Zhiping Tao
- Sinopec Research Institute of Petroleum Processing Co., Ltd., 18 Xueyuan Road, Haidian District, Beijing 100083, PR China
| | - Chong-Wen Zhou
- School of Energy and Power Engineering, Beihang University, Beijing 100191, PR China.
- Combustion Chemistry Centre, School of Biological and Chemical Sciences, MaREI, University of Galway, Galway H91 TK33, Ireland
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2
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Sun C, Xu B, Zeng Y. Pressure and temperature dependent kinetics and the reaction mechanism of Criegee intermediates with vinyl alcohol: a theoretical study. Phys Chem Chem Phys 2024; 26:9524-9533. [PMID: 38451236 DOI: 10.1039/d3cp06115a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/08/2024]
Abstract
Criegee intermediates (CIs), the key intermediates in the ozonolysis of olefins in atmosphere, have received much attention due to their high activity. The reaction mechanism of the most simple Criegee intermediate CH2OO with vinyl alcohol (VA) was investigated by using the HL//M06-2X/def2TZVP method. The temperature and pressure dependent rate constant and product branching ratio were calculated using the master equation method. For CH2OO + syn-VA, 1,4-insertion is the main reaction channel while for the CH2OO + anti-VA, cycloaddition and 1,2-insertion into the O-H bond are more favorable than the 1,4-insertion reaction. The 1,4-insertion or cycloaddition intermediates are stabilized collisionally at 300 K and 760 torr, and the dissociation products involving OH are formed at higher temperature and lower pressure. The rate constants of the CH2OO reaction with syn-VA and anti-VA both show negative temperature effects, and they are 2.95 × 10-11 and 2.07 × 10-13 cm3 molecule-1 s-1 at 300 K, respectively, and the former is agreement with the prediction in the literature.
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Affiliation(s)
- Cuihong Sun
- Shijiazhuang Key Laboratory of Low Carbon Energy Materials, Technology Innovation Center of HeBei for Heterocyclic Compound, College of Chemical Engineering, Shijiazhuang University, Shijiazhuang 050035, P. R. China
| | - Baoen Xu
- Shijiazhuang Key Laboratory of Low Carbon Energy Materials, Technology Innovation Center of HeBei for Heterocyclic Compound, College of Chemical Engineering, Shijiazhuang University, Shijiazhuang 050035, P. R. China
| | - Yanli Zeng
- College of Chemistry and Materials Science, Hebei Normal University, Shijiazhuang 050024, P.R. China.
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3
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Cho J, Rösch D, Tao Y, Osborn DL, Klippenstein SJ, Sheps L, Sivaramakrishnan R. Modeling-Experiment-Theory Analysis of Reactions Initiated from Cl + Methyl Formate. J Phys Chem A 2023; 127:9804-9819. [PMID: 37937747 DOI: 10.1021/acs.jpca.3c05085] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2023]
Abstract
Methyl formate (MF; CH3OCHO) is the smallest representative of esters, which are common components of biodiesel. The present study characterizes the thermal dissociation kinetics of the radicals formed by H atom abstraction from MF─CH3OCO and CH2OCHO─through a combination of modeling, experiment, and theory. For the experimental effort, excimer laser photolysis of Cl2 was used as a source of Cl atoms to initiate reactions with MF in the gas phase. Time-resolved species profiles of MF, Cl2, HCl, CO2, CH3, CH3Cl, CH2O, and CH2ClOCHO were measured and quantified using photoionization mass spectrometry at temperatures of 400-750 K and 10 Torr. The experimental data were simulated using a kinetic model, which was informed by ab initio-based theoretical kinetics calculations and included chlorine chemistry and secondary reactions of radical decomposition products. We calculated the rate coefficients for the H-abstraction reactions Cl + MF → HCl + CH3OCO (R1a) and Cl + MF → HCl + CH2OCHO (R1b): k1a,theory = 6.71 × 10-15·T1.14·exp(-606/T) cm3/molecule·s; k1b,theory = 4.67 × 10-18·T2.21·exp(-245/T) cm3/molecule·s over T = 200-2000 K. Electronic structure calculations indicate that the barriers to CH3OCO and CH2OCHO dissociation are 13.7 and 31.6 kcal/mol and lead to CH3 + CO2 (R3) and CH2O + HCO (R5), respectively. The master equation-based theoretical rate coefficients are k3,theory (P = ∞) = 2.94 × 109·T1.21·exp(-6209/T) s-1 and k5,theory (P = ∞) = 8.45 × 108·T1.39·exp(-15132/T) s-1 over T = 300-1500 K. The calculated branching fractions into R1a and R1b and the rate coefficient for R5 were validated by modeling of the experimental species time profiles and found to be in excellent agreement with theory. Additionally, we found that the bimolecular reactions CH2OCHO + Cl, CH2OCHO + Cl2, and CH3 + Cl2 were critical to accurately model the experimental data and constrain the kinetics of MF-radicals. Inclusion of the kinetic parameters determined in this study showed a significant impact on combustion simulations of larger methyl esters, which are considered as biodiesel surrogates.
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Affiliation(s)
- Jaeyoung Cho
- Chemical Sciences & Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Daniel Rösch
- Combustion Research Facility, Sandia National Laboratories, Livermore, California 94551-0969, United States
| | - Yujie Tao
- Chemical Sciences & Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - David L Osborn
- Combustion Research Facility, Sandia National Laboratories, Livermore, California 94551-0969, United States
| | - Stephen J Klippenstein
- Chemical Sciences & Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Leonid Sheps
- Combustion Research Facility, Sandia National Laboratories, Livermore, California 94551-0969, United States
| | - Raghu Sivaramakrishnan
- Chemical Sciences & Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
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4
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Li Y, Zhang RM, Xu X. Theoretical Kinetics studies of isoprene peroxy radical chemistry: The fate of Z-δ-(4-OH, 1-OO)-ISOPOO radical. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2023; 266:115553. [PMID: 37839188 DOI: 10.1016/j.ecoenv.2023.115553] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2023] [Revised: 09/19/2023] [Accepted: 10/05/2023] [Indexed: 10/17/2023]
Abstract
The OH radical recycling mechanism in isoprene oxidation is one of the most exciting topics in atmospheric chemistry, and the corresponding studies expand our understanding of oxidation mechanisms of volatile organic compounds in the troposphere and provide reliable evidence to improve and develop conventional atmospheric models. In this work, we performed a detailed theoretical kinetics study on the Z-δ-(4-OH, 1-OO)-ISOPOO radical chemistry, which is proposed as the heart of OH recycling in isoprene oxidation. With the full consideration of its accumulation and consumption channels, we studied and discussed the fate of Z-δ-(4-OH, 1-OO)-ISOPOO radical by solving the energy-resolved master equation over a broad range of conditions, including not only room temperatures but also high temperatures of a forest fire or low temperatures and pressures of the upper troposphere. We found non-negligible pressure dependence of its fate at combustion temperatures (up to two orders of magnitude) and demonstrated the significance of both the multi-structural torsional anharmonicity and tunneling for accurately calculating kinetics of the studied system. More interestingly, the tunneling effect on the phenomenological rate constants of the H-shift reaction channel is also found to be pressure-dependent due to the competition with the O2 loss reaction. In addition, our time evolution calculations revealed a two-stage behavior of critical species in this reaction system and estimated the shortest half-lives for the Z-δ-(4-OH, 1-OO)-ISOPOO radical at various temperatures, pressures and altitudes. This detailed kinetics study of Z-δ-(4-OH, 1-OO)-ISOPOO radical chemistry offers a typical example to deeply understand the core mechanism of OH recycling pathways in isoprene oxidation, and provides valuable insights for promoting the development of relevant atmospheric models.
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Affiliation(s)
- Yan Li
- Center for Combustion Energy, Department of Energy and Power Engineering, and Key Laboratory for Thermal Science and Power Engineering of Ministry of Education, Tsinghua University, Beijing 100084, China
| | - Rui Ming Zhang
- Center for Combustion Energy, Department of Energy and Power Engineering, and Key Laboratory for Thermal Science and Power Engineering of Ministry of Education, Tsinghua University, Beijing 100084, China
| | - Xuefei Xu
- Center for Combustion Energy, Department of Energy and Power Engineering, and Key Laboratory for Thermal Science and Power Engineering of Ministry of Education, Tsinghua University, Beijing 100084, China.
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5
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Xu R, Meisner J, Chang AM, Thompson KC, Martínez TJ. First principles reaction discovery: from the Schrodinger equation to experimental prediction for methane pyrolysis. Chem Sci 2023; 14:7447-7464. [PMID: 37449065 PMCID: PMC10337770 DOI: 10.1039/d3sc01202f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Accepted: 06/02/2023] [Indexed: 07/18/2023] Open
Abstract
Our recent success in exploiting graphical processing units (GPUs) to accelerate quantum chemistry computations led to the development of the ab initio nanoreactor, a computational framework for automatic reaction discovery and kinetic model construction. In this work, we apply the ab initio nanoreactor to methane pyrolysis, from automatic reaction discovery to path refinement and kinetic modeling. Elementary reactions occurring during methane pyrolysis are revealed using GPU-accelerated ab initio molecular dynamics simulations. Subsequently, these reaction paths are refined at a higher level of theory with optimized reactant, product, and transition state geometries. Reaction rate coefficients are calculated by transition state theory based on the optimized reaction paths. The discovered reactions lead to a kinetic model with 53 species and 134 reactions, which is validated against experimental data and simulations using literature kinetic models. We highlight the advantage of leveraging local brute force and Monte Carlo sensitivity analysis approaches for efficient identification of important reactions. Both sensitivity approaches can further improve the accuracy of the methane pyrolysis kinetic model. The results in this work demonstrate the power of the ab initio nanoreactor framework for computationally affordable systematic reaction discovery and accurate kinetic modeling.
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Affiliation(s)
- Rui Xu
- Department of Chemistry, The PULSE Institute, Stanford University Stanford CA 94305 USA
- SLAC National Accelerator Laboratory 2575 Sand Hill Road Menlo Park CA 94025 USA
| | - Jan Meisner
- Department of Chemistry, The PULSE Institute, Stanford University Stanford CA 94305 USA
- SLAC National Accelerator Laboratory 2575 Sand Hill Road Menlo Park CA 94025 USA
| | - Alexander M Chang
- Department of Chemistry, The PULSE Institute, Stanford University Stanford CA 94305 USA
- SLAC National Accelerator Laboratory 2575 Sand Hill Road Menlo Park CA 94025 USA
| | - Keiran C Thompson
- Department of Chemistry, The PULSE Institute, Stanford University Stanford CA 94305 USA
- SLAC National Accelerator Laboratory 2575 Sand Hill Road Menlo Park CA 94025 USA
| | - Todd J Martínez
- Department of Chemistry, The PULSE Institute, Stanford University Stanford CA 94305 USA
- SLAC National Accelerator Laboratory 2575 Sand Hill Road Menlo Park CA 94025 USA
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6
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Dana AG, Johnson MS, Allen JW, Sharma S, Raman S, Liu M, Gao CW, Grambow CA, Goldman MJ, Ranasinghe DS, Gillis RJ, Payne AM, Li Y, Dong X, Spiekermann KA, Wu H, Dames EE, Buras ZJ, Vandewiele NM, Yee NW, Merchant SS, Buesser B, Class CA, Goldsmith F, West RH, Green WH. Automated reaction kinetics and network exploration (Arkane): A statistical mechanics, thermodynamics, transition state theory, and master equation software. INT J CHEM KINET 2023. [DOI: 10.1002/kin.21637] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/05/2023]
Affiliation(s)
- Alon Grinberg Dana
- Department of Chemical Engineering Massachusetts Institute of Technology Cambridge Massachusetts USA
- The Wolfson Department of Chemical Engineering and Grand Technion Energy Program (GTEP) Technion – Israel Institute of Technology Haifa Israel
| | - Matthew S. Johnson
- Department of Chemical Engineering Massachusetts Institute of Technology Cambridge Massachusetts USA
| | - Joshua W. Allen
- Department of Chemical Engineering Massachusetts Institute of Technology Cambridge Massachusetts USA
| | - Sandeep Sharma
- Department of Chemistry University of Colorado Boulder CO USA
| | - Sumathy Raman
- Department of Chemical Engineering Massachusetts Institute of Technology Cambridge Massachusetts USA
| | - Mengjie Liu
- Department of Chemical Engineering Massachusetts Institute of Technology Cambridge Massachusetts USA
| | - Connie W. Gao
- Department of Chemical Engineering Massachusetts Institute of Technology Cambridge Massachusetts USA
| | - Colin A. Grambow
- Department of Chemical Engineering Massachusetts Institute of Technology Cambridge Massachusetts USA
| | - Mark J. Goldman
- Department of Chemical Engineering Massachusetts Institute of Technology Cambridge Massachusetts USA
| | - Duminda S. Ranasinghe
- Department of Chemical Engineering Massachusetts Institute of Technology Cambridge Massachusetts USA
| | - Ryan J. Gillis
- Department of Chemical Engineering Massachusetts Institute of Technology Cambridge Massachusetts USA
| | - A. Mark Payne
- Department of Chemical Engineering Massachusetts Institute of Technology Cambridge Massachusetts USA
| | - Yi‐Pei Li
- Department of Chemical Engineering National Taiwan University Taipei Taiwan
| | - Xiaorui Dong
- Department of Chemical Engineering Massachusetts Institute of Technology Cambridge Massachusetts USA
| | - Kevin A. Spiekermann
- Department of Chemical Engineering Massachusetts Institute of Technology Cambridge Massachusetts USA
| | - Haoyang Wu
- Department of Chemical Engineering Massachusetts Institute of Technology Cambridge Massachusetts USA
| | - Enoch E. Dames
- Department of Chemical Engineering Massachusetts Institute of Technology Cambridge Massachusetts USA
| | - Zachary J. Buras
- Department of Chemical Engineering Massachusetts Institute of Technology Cambridge Massachusetts USA
| | - Nick M. Vandewiele
- Department of Chemical Engineering Massachusetts Institute of Technology Cambridge Massachusetts USA
| | - Nathan W. Yee
- Department of Chemical Engineering Massachusetts Institute of Technology Cambridge Massachusetts USA
| | - Shamel S. Merchant
- Department of Chemical Engineering Massachusetts Institute of Technology Cambridge Massachusetts USA
| | - Beat Buesser
- Department of Chemical Engineering Massachusetts Institute of Technology Cambridge Massachusetts USA
| | - Caleb A. Class
- Department of Chemical Engineering Massachusetts Institute of Technology Cambridge Massachusetts USA
| | | | - Richard H. West
- Department of Chemical Engineering Northeastern University Boston Massachusetts USA
| | - William H. Green
- Department of Chemical Engineering Massachusetts Institute of Technology Cambridge Massachusetts USA
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7
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Cho J, Mulvihill CR, Klippenstein SJ, Sivaramakrishnan R. Bimolecular Peroxy Radical (RO 2) Reactions and Their Relevance in Radical Initiated Oxidation of Hydrocarbons. J Phys Chem A 2023; 127:300-315. [PMID: 36562763 DOI: 10.1021/acs.jpca.2c06960] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The kinetics of peroxy radical (RO2) reactions have been of long-standing interest in atmospheric and combustion chemistry. Nevertheless, the lack of kinetic studies at higher temperatures for their reactions with other radicals such as OH has precluded the inclusion of this class of reactions in detailed kinetics models developed for combustion applications. In this work, guided by the limited room-temperature experimental studies on selected alkyl-peroxy radicals and literature theoretical kinetics on the prototypical CH3O2 + OH system, we have performed parametric studies on the effect of uncertainties in the rate coefficients and branching ratios to potential product channels for RO2 + OH reactions at higher temperatures. Literature kinetics models were used to simulate autoignition delays, laminar flame speeds, and speciation profiles in flow and stirred reactors for a variety of common combustion-relevant fuels. Inclusion of RO2 + OH reactions was found to retard autoignition in fuel-lean (φ = 0.5) mixtures of ethane and dimethyl ether in air. The observed effects were noticeably more pronounced in ozone-enriched combustion of ethane and dimethyl ether. The simulations also examined the influence of ozone doping levels, pressures, and equivalence ratios for both ethane and dimethyl ether oxidation. Sensitivity and flux analyses revealed that the RO2 + OH reaction is a significant sink of RO2 radicals at the early stage of autoignition, affecting fuel oxidation through RO2 ↔ QOOH, RO2 ↔ alkene + HO2, or RO2 + HO2 ↔ ROOH + O2. Additionally, the kinetic stability of the trioxide formed from RO2 + OH reactions was investigated using master equation analyses. Last, we discuss other bimolecular reactions that are missing in literature kinetics models but are relevant to hydrocarbon oxidation initiated by external radical sources (plasma-enhanced, ozone-enriched combustion, etc.). The present simulations provide a strong motivation for better characterizing the bimolecular kinetics of peroxy radicals.
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Affiliation(s)
- Jaeyoung Cho
- Chemical Sciences & Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Clayton R Mulvihill
- Chemical Sciences & Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Stephen J Klippenstein
- Chemical Sciences & Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Raghu Sivaramakrishnan
- Chemical Sciences & Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
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8
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Couch DE, Mulvihill CR, Sivaramakrishnan R, Au K, Taatjes CA, Sheps L. Quantification of Key Peroxy and Hydroperoxide Intermediates in the Low-Temperature Oxidation of Dimethyl Ether. J Phys Chem A 2022; 126:9497-9509. [DOI: 10.1021/acs.jpca.2c06959] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- David E. Couch
- Combustion Research Facility, Sandia National Laboratories, Livermore, California94551, United States
| | - Clayton R. Mulvihill
- Chemical Sciences and Engineering, Argonne National Laboratory, Lemont, Illinois60439, United States
| | - Raghu Sivaramakrishnan
- Chemical Sciences and Engineering, Argonne National Laboratory, Lemont, Illinois60439, United States
| | - Kendrew Au
- Combustion Research Facility, Sandia National Laboratories, Livermore, California94551, United States
| | - Craig A. Taatjes
- Combustion Research Facility, Sandia National Laboratories, Livermore, California94551, United States
| | - Leonid Sheps
- Combustion Research Facility, Sandia National Laboratories, Livermore, California94551, United States
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9
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Ventura ON, Segovia M, Vega-Teijido M, Katz A, Kieninger M, Tasinato N, Salta Z. Correcting the Experimental Enthalpies of Formation of Some Members of the Biologically Significant Sulfenic Acids Family. J Phys Chem A 2022; 126:6091-6109. [PMID: 36044372 DOI: 10.1021/acs.jpca.2c04235] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Sulfenic acids are important intermediates in the oxidation of cysteine thiol groups in proteins by reactive oxygen species. The mechanism is influenced heavily by the presence of polar groups, other thiol groups, and solvent, all of which determines the need to compute precisely the energies involved in the process. Surprisingly, very scarce experimental information exists about a very basic property of sulfenic acids, the enthalpies of formation. In this Article, we use high level quantum chemical methods to derive the enthalpy of formation at 298.15 K of methane-, ethene-, ethyne-, and benzenesulfenic acids, the only ones for which some experimental information exists. The methods employed were tested against well-known experimental data of related species and extensive CCSD(T) calculations. Our best results consistently point out to a much lower enthalpy of formation of methanesulfenic acid, CH3SOH (ΔfH0(298.15K) = -35.1 ± 0.4 kcal mol-1), than the one reported in the NIST thermochemical data tables. The enthalpies of formation derived for ethynesulfenic acid, HC≡CSOH, +32.9 ± 1.0 kcal/mol, and benzenesulfenic acid, C6H5SOH, -2.6 ± 0.6 kcal mol-1, also differ markedly from the experimental values, while the enthalpy of formation of ethenesulfenic acid CH2CHSOH, not available experimentally, was calculated as -11.2 ± 0.7 kcal mol-1.
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Affiliation(s)
- Oscar N Ventura
- Computational Chemistry and Biology Group, CCBG, DETEMA, Facultad de Química, Universidad de la República, 11400 Montevideo, Uruguay
| | - Marc Segovia
- Computational Chemistry and Biology Group, CCBG, DETEMA, Facultad de Química, Universidad de la República, 11400 Montevideo, Uruguay
| | - Mauricio Vega-Teijido
- Computational Chemistry and Biology Group, CCBG, DETEMA, Facultad de Química, Universidad de la República, 11400 Montevideo, Uruguay
| | - Aline Katz
- Computational Chemistry and Biology Group, CCBG, DETEMA, Facultad de Química, Universidad de la República, 11400 Montevideo, Uruguay
| | - Martina Kieninger
- Computational Chemistry and Biology Group, CCBG, DETEMA, Facultad de Química, Universidad de la República, 11400 Montevideo, Uruguay
| | - Nicola Tasinato
- SMART Lab, Scuola Normale Superiore, piazza dei Cavalieri 7, 56126 Pisa, Italy
| | - Zoi Salta
- SMART Lab, Scuola Normale Superiore, piazza dei Cavalieri 7, 56126 Pisa, Italy
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10
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Salta Z, Vega-Teijido M, Katz A, Tasinato N, Barone V, Ventura ON. Dipolar 1,3-cycloaddition of thioformaldehyde S-methylide (CH 2 SCH 2 ) to ethylene and acetylene. A comparison with (valence) isoelectronic O 3 , SO 2 , CH 2 OO and CH 2 SO. J Comput Chem 2022; 43:1420-1433. [PMID: 35662073 DOI: 10.1002/jcc.26946] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Revised: 05/17/2022] [Accepted: 05/17/2022] [Indexed: 11/08/2022]
Abstract
Methods rooted in the density functional theory and in the coupled cluster ansatz were employed to investigate the cycloaddition reactions to ethylene and acetylene of 1,3-dipolar species including ozone and the derivatives issued from replacement of the central oxygen atom by the valence-isoelectronic sulfur atom, and/or of one or both terminal oxygen atoms by the isoelectronic CH2 group. This gives rise to five different 1,3-dipolar compounds, namely ozone itself (O3 ), sulfur dioxide (SO2 ), the simplest Criegee intermediate (CH2 OO), sulfine (CH2 SO), and thioformaldehyde S-methylide (CH2 SCH2 , TSM). The experimental and accurate theoretical data available for some of those molecules were employed to assess the accuracy of two last-generation composite methods employing conventional or explicitly correlated post-Hartree-Fock contributions (jun-Cheap and SVECV-f12, respectively), which were then applied to investigate the reactivity of TSM. The energy barriers provided by both composite methods are very close (the average values for the two composite methods are 7.1 and 8.3 kcal mol-1 for the addition to ethylene and acetylene, respectively) and comparable to those ruling the corresponding additions of ozone (4.0 and 7.7 kcal mol-1 , respectively). These and other evidences strongly suggest that, at least in the case of cycloadditions, the reactivity of TSM is similar to that of O3 and very different from that of SO2 .
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Affiliation(s)
- Zoi Salta
- SMART Lab, Scuola Normale Superiore, Pisa, Italy
| | - Mauricio Vega-Teijido
- Computational Chemistry and Biology Group, CCBG, DETEMA, Facultad de Química, Universidad de la República, Montevideo, Uruguay
| | - Aline Katz
- Computational Chemistry and Biology Group, CCBG, DETEMA, Facultad de Química, Universidad de la República, Montevideo, Uruguay
| | | | | | - Oscar N Ventura
- Computational Chemistry and Biology Group, CCBG, DETEMA, Facultad de Química, Universidad de la República, Montevideo, Uruguay
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11
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NAST: Nonadiabatic Statistical Theory Package for Predicting Kinetics of Spin-Dependent Processes. Top Curr Chem (Cham) 2022; 380:15. [PMID: 35201520 DOI: 10.1007/s41061-022-00366-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Accepted: 01/15/2022] [Indexed: 10/19/2022]
Abstract
We present a nonadiabatic statistical theory (NAST) package for predicting kinetics of spin-dependent processes, such as intersystem crossings, spin-forbidden unimolecular reactions, and spin crossovers. The NAST package can calculate the probabilities and rates of transitions between the electronic states of different spin multiplicities. Both the microcanonical (energy-dependent) and canonical (temperature-dependent) rate constants can be obtained. Quantum effects, including tunneling, zero-point vibrational energy, and reaction path interference, can be accounted for. In the limit of an adiabatic unimolecular reaction proceeding on a single electronic state, NAST reduces to the traditional transition state theory. Because NAST requires molecular properties at only a few points on potential energy surfaces, it can be applied to large molecular systems, used with accurate high-level electronic structure methods, and employed to study slow nonadiabatic processes. The essential NAST input data include the nuclear Hessian at the reactant minimum, as well as the nuclear Hessians, energy gradients, and spin-orbit coupling at the minimum energy crossing point (MECP) between two states. The additional computational tools included in the NAST package can be used to extract the required input data from the output files of electronic structure packages, calculate the effective Hessian at the MECP, and fit the reaction coordinate for more advanced NAST calculations. We describe the theory, its implementation, and three examples of application to different molecular systems.
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12
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Zhang RM, Chen W, Truhlar DG, Xu X. Master Equation Study of Hydrogen Abstraction from HCHO by OH Via a Chemically Activated Intermediate. Faraday Discuss 2022; 238:431-460. [DOI: 10.1039/d2fd00024e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The abstraction reaction of hydrogen from formaldehyde by OH radical plays an important role in formaldehyde oxidation. The reaction involves a bimolecular association to form a chemically activated hydrogen-bonded reaction...
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13
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Savee J, Sztáray B, Hemberger P, Zádor J, Bodi A, Osborn DL. Unimolecular isomerisation of 1,5-hexadiyne observed by threshold photoelectron photoion coincidence spectroscopy. Faraday Discuss 2022; 238:645-664. [DOI: 10.1039/d2fd00028h] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The unimolecular isomerisation of the prompt propargyl + propargyl "head-to-head" adduct, 1,5- hexadiyne, to fulvene and benzene by the 3,4-dimethylenecyclobut-1-ene (DMCB) intermediate (all C6H6) was studied in the high-pressure limit...
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14
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Klippenstein SJ. Spiers Memorial Lecture: theory of unimolecular reactions. Faraday Discuss 2022; 238:11-67. [DOI: 10.1039/d2fd00125j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
One hundred years ago, at an earlier Faraday Discussion meeting, Lindemann presented a mechanism that provides the foundation for contemplating the pressure dependence of unimolecular reactions. Since that time, our...
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15
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A theoretical study of β-hydroxybutenyl with O2 on the HOC4H6OO· potential energy surface. Theor Chem Acc 2021. [DOI: 10.1007/s00214-021-02842-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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16
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Rogers CO, Lockwood KS, Nguyen QLD, Labbe NJ. Diol isomer revealed as a source of methyl ketene from propionic acid unimolecular decomposition. INT J CHEM KINET 2021. [DOI: 10.1002/kin.21532] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Cory O. Rogers
- Department of Mechanical Engineering University of Colorado Boulder Boulder Colorado USA
| | - Katherine S. Lockwood
- Department of Mechanical Engineering University of Colorado Boulder Boulder Colorado USA
| | - Quynh L. D. Nguyen
- JILA Department of Physics University of Colorado Boulder Boulder Colorado USA
- National Institute of Standards and Technology Boulder Colorado USA
| | - Nicole J. Labbe
- Department of Mechanical Engineering University of Colorado Boulder Boulder Colorado USA
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17
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Sikes T, Banyon C, Schwind RA, Lynch PT, Comandini A, Sivaramakrishnan R, Tranter RS. Initiation reactions in the high temperature decomposition of styrene. Phys Chem Chem Phys 2021; 23:18432-18448. [PMID: 34612384 PMCID: PMC8409502 DOI: 10.1039/d1cp02437j] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The thermal decomposition of styrene was investigated in a combined experimental, theory and modeling study with particular emphasis placed on the initial dissociation reactions. Two sets of shock tube/time-of-flight mass spectrometry (TOF-MS) experiments were performed to identify reaction products and their order of appearance. One set of experiments was conducted with a miniature high repetition rate shock tube at the Advanced Light Source at Lawrence Berkeley National Laboratory using synchrotron vacuum ultraviolet photoionization. The other set of experiments was performed in a diaphragmless shock tube (DFST) using electron impact ionization. The datasets span 1660–2260 K and 0.5–12 atm. The results show a marked transition from aromatic products at low temperatures to polyacetylenes, up to C8H2, at high temperatures. The TOF-MS experiments were complemented by DFST/LS (laser schlieren densitometry) experiments covering 1800–2250 K and 60–240 Torr. These were particularly sensitive to the initial dissociation reactions. These reactions were investigated theoretically and revealed the dissociation of styrene to be a complex multichannel process with strong pressure and temperature dependencies that were evaluated with multi-well master equation simulations. Simulations of the LS data with a mechanism developed in this work are in excellent agreement with the experimental data. From these simulations, rate coefficients for the dissociation of styrene were obtained that are in good agreement with the theoretical predictions. The simulation results also provide fair predictions of the temperature and pressure dependencies of the products observed in the TOF-MS studies. Prior experimental studies of styrene pyrolysis concluded that the main products were benzene and acetylene. In contrast, this study finds that the majority of styrene dissociates to create five styryl radical isomers. Of these, α-styryl accounts for about 50% with the other isomers consuming approximately 20%. It was also found that C–C bond scission to phenyl and vinyl radicals consumes up to 25% of styrene. Finally the dissociation of styrene to benzene and vinylidene accounts for roughly 5% of styrene consumption. Comments are made on the apparent differences between the results of this work and prior literature. A combined theoretical and experimental study showing styrene primarily decomposes to styryl radicals + H.![]()
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Affiliation(s)
- Travis Sikes
- Chemical Sciences and Engineering Division, Argonne National Laboratory, 9700 South Cass Ave., Lemont, IL 60439, USA.
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18
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Chloro(4-methylpent-3-en-1-ynyl)carbene: IR spectrum, structure, photochemical transformations, and reactions with alkenes. Russ Chem Bull 2021. [DOI: 10.1007/s11172-021-3254-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
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19
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Ferhoune I, Guemini M, Rezgui Y. Effect of the Chemical Structure of Hydrocarbons on the Emissions of CO, CO2 and Soot Precursors Issued from Cyclohexane and Benzene Premixed Flames. KINETICS AND CATALYSIS 2021. [DOI: 10.1134/s0023158421040029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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20
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Zhao L, Lu W, Ahmed M, Zagidullin MV, Azyazov VN, Morozov AN, Mebel AM, Kaiser RI. Gas-phase synthesis of benzene via the propargyl radical self-reaction. SCIENCE ADVANCES 2021; 7:7/21/eabf0360. [PMID: 34020951 PMCID: PMC8139581 DOI: 10.1126/sciadv.abf0360] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Accepted: 03/31/2021] [Indexed: 06/01/2023]
Abstract
Polycyclic aromatic hydrocarbons (PAHs) have been invoked in fundamental molecular mass growth processes in our galaxy. We provide compelling evidence of the formation of the very first ringed aromatic and building block of PAHs-benzene-via the self-recombination of two resonantly stabilized propargyl (C3H3) radicals in dilute environments using isomer-selective synchrotron-based mass spectrometry coupled to theoretical calculations. Along with benzene, three other structural isomers (1,5-hexadiyne, fulvene, and 2-ethynyl-1,3-butadiene) and o-benzyne are detected, and their branching ratios are quantified experimentally and verified with the aid of computational fluid dynamics and kinetic simulations. These results uncover molecular growth pathways not only in interstellar, circumstellar, and solar systems environments but also in combustion systems, which help us gain a better understanding of the hydrocarbon chemistry of our universe.
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Affiliation(s)
- Long Zhao
- Department of Chemistry, University of Hawaii at Manoa, Honolulu, HI 96822, USA
| | - Wenchao Lu
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Musahid Ahmed
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.
| | | | - Valeriy N Azyazov
- Lebedev Physical Institute, Samara 443011, Russian Federation
- Samara National Research University, Samara 443086, Russian Federation
| | - Alexander N Morozov
- Department of Chemistry and Biochemistry, Florida International University, Miami, FL 33199, USA
| | - Alexander M Mebel
- Department of Chemistry and Biochemistry, Florida International University, Miami, FL 33199, USA.
| | - Ralf I Kaiser
- Department of Chemistry, University of Hawaii at Manoa, Honolulu, HI 96822, USA.
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21
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Zaleski DP, Sivaramakrishnan R, Weller HR, Seifert NA, Bross DH, Ruscic B, Moore KB, Elliott SN, Copan AV, Harding LB, Klippenstein SJ, Field RW, Prozument K. Substitution Reactions in the Pyrolysis of Acetone Revealed through a Modeling, Experiment, Theory Paradigm. J Am Chem Soc 2021; 143:3124-3142. [PMID: 33615780 DOI: 10.1021/jacs.0c11677] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The development of high-fidelity mechanisms for chemically reactive systems is a challenging process that requires the compilation of rate descriptions for a large and somewhat ill-defined set of reactions. The present unified combination of modeling, experiment, and theory provides a paradigm for improving such mechanism development efforts. Here we combine broadband rotational spectroscopy with detailed chemical modeling based on rate constants obtained from automated ab initio transition state theory-based master equation calculations and high-level thermochemical parametrizations. Broadband rotational spectroscopy offers quantitative and isomer-specific detection by which branching ratios of polar reaction products may be obtained. Using this technique, we observe and characterize products arising from H atom substitution reactions in the flash pyrolysis of acetone (CH3C(O)CH3) at a nominal temperature of 1800 K. The major product observed is ketene (CH2CO). Minor products identified include acetaldehyde (CH3CHO), propyne (CH3CCH), propene (CH2CHCH3), and water (HDO). Literature mechanisms for the pyrolysis of acetone do not adequately describe the minor products. The inclusion of a variety of substitution reactions, with rate constants and thermochemistry obtained from automated ab initio kinetics predictions and Active Thermochemical Tables analyses, demonstrates an important role for such processes. The pathway to acetaldehyde is shown to be a direct result of substitution of acetone's methyl group by a free H atom, while propene formation arises from OH substitution in the enol form of acetone by a free H atom.
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Affiliation(s)
- Daniel P Zaleski
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States.,Department of Chemistry, Colgate University, Hamilton, New York 13346, United States
| | - Raghu Sivaramakrishnan
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Hailey R Weller
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States.,Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, Tennessee 37235, United States
| | - Nathan A Seifert
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - David H Bross
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Branko Ruscic
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Kevin B Moore
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Sarah N Elliott
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Andreas V Copan
- Emmanuel College, Natural Sciences Department, Franklin Springs, Georgia 30639, United States
| | - Lawrence B Harding
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Stephen J Klippenstein
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Robert W Field
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Kirill Prozument
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
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22
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Agúndez M, Cabezas C, Tercero B, Marcelino N, Gallego JD, de Vicente P, Cernicharo J. Discovery of the propargyl radical (CH 2CCH) in TMC-1: one of the most abundant radicals ever found and a key species for cyclization to benzene in cold dark clouds. ASTRONOMY AND ASTROPHYSICS 2021; 647:L10. [PMID: 33850331 PMCID: PMC7610583 DOI: 10.1051/0004-6361/202140553] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
We present the first identification in interstellar space of the propargyl radical (CH2CCH). This species was observed in the cold dark cloud TMC-1 using the Yebes 40m telescope. The six strongest hyperfine components of the 20,2-10,1 rotational transition, lying at 37.46 GHz, were detected with signal-to-noise ratios in the range 4.6-12.3 σ. We derive a column density of 8.7 × 1013 cm-2 for CH2CCH, which translates to a fractional abundance relative to H2 of 8.7 × 10-9. This radical has a similar abundance to methyl acetylene, with an abundance ratio CH2CCH/CH3CCH close to one. The propargyl radical is thus one of the most abundant radicals detected in TMC-1, and it is probably the most abundant organic radical with a certain chemical complexity ever found in a cold dark cloud. We constructed a gas-phase chemical model and find calculated abundances that agree with, or fall two orders of magnitude below, the observed value depending on the poorly constrained low-temperature reactivity of CH2CCH with neutral atoms. According to the chemical model, the propargyl radical is essentially formed by the C + C2H4 reaction and by the dissociative recombination of C3Hn + ions with n = 4-6. The propargyl radical is believed to control the synthesis of the first aromatic ring in combustion processes, and it probably plays a key role in the synthesis of large organic molecules and cyclization processes to benzene in cold dark clouds.
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Affiliation(s)
- M. Agúndez
- Instituto de Física Fundamental, CSIC, Calle Serrano 123, E-28006 Madrid, Spain
| | - C. Cabezas
- Instituto de Física Fundamental, CSIC, Calle Serrano 123, E-28006 Madrid, Spain
| | - B. Tercero
- Observatorio Astronómico Nacional, IGN, Calle Alfonso XII 3, E-28014 Madrid, Spain
- Observatorio de Yebes, IGN, Cerro de la Palera s/n, E-19141 Yebes, Guadalajara, Spain
| | - N. Marcelino
- Instituto de Física Fundamental, CSIC, Calle Serrano 123, E-28006 Madrid, Spain
| | - J. D. Gallego
- Observatorio de Yebes, IGN, Cerro de la Palera s/n, E-19141 Yebes, Guadalajara, Spain
| | - P. de Vicente
- Observatorio de Yebes, IGN, Cerro de la Palera s/n, E-19141 Yebes, Guadalajara, Spain
| | - J. Cernicharo
- Instituto de Física Fundamental, CSIC, Calle Serrano 123, E-28006 Madrid, Spain
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23
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Chen W, Nguyen T, Lin M, Wang N, Matsui H. Experimental and theoretical studies on the reaction of H atom with C
3
H
6. INT J CHEM KINET 2020. [DOI: 10.1002/kin.21471] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Wei‐Yu Chen
- Department of Applied Chemistry National Chiao Tung University Hsinchu 30010 Taiwan
| | - Trong‐Nghia Nguyen
- Department of Applied Chemistry National Chiao Tung University Hsinchu 30010 Taiwan
- School of Chemical Engineering Hanoi University of Science and Technology Hanoi Vietnam
| | - Ming‐Chang Lin
- Department of Applied Chemistry National Chiao Tung University Hsinchu 30010 Taiwan
- Center for Emergent Functional Matter Science National Chiao Tung University Hsinchu 30010 Taiwan
| | - Niann‐Shiah Wang
- Department of Applied Chemistry National Chiao Tung University Hsinchu 30010 Taiwan
| | - Hiroyuki Matsui
- Department of Applied Chemistry National Chiao Tung University Hsinchu 30010 Taiwan
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24
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Vaghjiani GL, Sun H, Chambreau SD. Experimental and Theoretical Investigations of the Radical-Radical Reaction: N 2H 3 + NO 2. J Phys Chem A 2020; 124:10434-10446. [PMID: 33264012 DOI: 10.1021/acs.jpca.0c07985] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The N2H3 + NO2 reaction plays a key role during the early stages of hypergolic ignition between N2H4 and N2O4. Here for the first time, the reaction kinetics of N2H3 in excess NO2 was studied in 2.0 Torr of N2 and in the narrow temperature range 298-348 K in a pulsed photolysis flow-tube reactor coupled to a mass spectrometer. The temporal profile of the product, HONO, was determined by direct detection of the m/z +47 amu ion signal. For each chosen [NO2], the observed [HONO] trace was fitted to a biexponential kinetics expression, which yielded a value for the pseudo-first-order rate coefficient, k', for the reaction of N2H3 with NO2. The slope of the plot of k' versus [NO2] yielded a value for the observed bimolecular rate coefficient, kobs, which could be fitted to an Arrhenius expression of (2.36 ± 0.47) × 10-12 exp((520 ± 350)/T) cm3 molecule-1 s-1. The errors are 1σ and include estimated uncertainties in the NO2 concentration. The potential energy surface of N2H3 + NO2 was investigated by advanced ab initio quantum chemistry theories. It was found that the reaction occurs via a complex reaction mechanism, and all of the reaction channels have transition state energies below that of the entrance asymptote. The radical-radical addition forms the N2H3NO2 adducts, while roaming-mediated isomerization reactions yield the N2H3ONO isomers, which undergo rapid dissociation reactions to several sets of distinct products. The RRKM multiwell master equation simulations revealed that the major product channel involves the formation of trans-HONO and trans-N2H2 below 500 K and the formation of NO + NH2NHO above 500 K, which is nearly pressure independent. The pressure-dependent rate coefficients of the product channels were computed over a wide pressure-temperature range, which encompassed the experimental data.
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Affiliation(s)
- Ghanshyam L Vaghjiani
- In-Space Propulsion Branch, Air Force Research Laboratory, AFRL/RQRS, Edwards Air Force Base, California 93524, United States
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25
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Cao X, Gong C, Liu J, Ma H, Li Z, Wang J, Li X. Development of a detailed pyrolysis mechanism for C
1
–C
4
hydrocarbons under a wide range of temperature and pressure. INT J CHEM KINET 2020. [DOI: 10.1002/kin.21401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Xiaomei Cao
- College of Aeronautics and Astronautics Sichuan University Chengdu China
| | | | - Jianwen Liu
- Beijing Power Machinery Institute Beijing China
| | - Huimin Ma
- Beijing Power Machinery Institute Beijing China
| | - Zerong Li
- College of Chemistry Sichuan University Chengdu China
| | - Jingbo Wang
- College of Chemical Engineering Sichuan University Chengdu China
| | - Xiangyuan Li
- College of Chemical Engineering Sichuan University Chengdu China
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26
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Zhang RM, Xu X, Truhlar DG. Low-Pressure Limit of Competitive Unimolecular Reactions. J Am Chem Soc 2020; 142:16064-16071. [PMID: 32847352 DOI: 10.1021/jacs.0c07692] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Barker and Ortiz found unusual falloff effects in the flux coefficients of the competitive unimolecular reactions of 2-methylhexyl radicals, and they concluded that this might have important effects on the rate constants of reactions with higher thresholds. To study this effect, we carried out master equation calculations of the same reaction system to learn whether this effect shows up in measurable rate constants, and the answer is yes. We also studied specially designed mechanisms to reveal that the various reactive pathways connecting the reagents can have a large effect on the rate constants, causing them to be quite different than if the reactions proceeded independently, and that reactions with significantly higher barriers may nevertheless have larger rate constants. This provides a new perspective for interpreting and predicting the kinetics of competitive unimolecular reactions.
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Affiliation(s)
- Rui Ming Zhang
- Center for Combustion Energy, Department of Energy and Power Engineering, and Key Laboratory for Thermal Science and Power Engineering of Ministry of Education, Tsinghua University, Beijing 100084, China.,Department of Chemistry, Chemical Theory Center, and Minnesota Supercomputing Institute, University of Minnesota, Minneapolis, Minnesota 55455-0431, United States
| | - Xuefei Xu
- Center for Combustion Energy, Department of Energy and Power Engineering, and Key Laboratory for Thermal Science and Power Engineering of Ministry of Education, Tsinghua University, Beijing 100084, China
| | - Donald G Truhlar
- Department of Chemistry, Chemical Theory Center, and Minnesota Supercomputing Institute, University of Minnesota, Minneapolis, Minnesota 55455-0431, United States
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27
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Randazzo JB, Sivaramakrishnan R, Jasper AW, Sikes T, Lynch PT, Tranter RS. An experimental and theoretical study of the high temperature reactions of the four butyl radical isomers. Phys Chem Chem Phys 2020; 22:18304-18319. [PMID: 32785311 DOI: 10.1039/d0cp02404j] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The high temperature gas phase chemistry of the four butyl radical isomers (n-butyl, sec-butyl, iso-butyl, and tert-butyl) was investigated in a combined experimental and theoretical study. Organic nitrites were used as convenient and clean sources of each of the butyl radical isomers. Rate coefficients for dissociation of each nitrite were obtained experimentally and are at, or close to, the high pressure limit. Low pressure experiments were performed in a diaphragmless shock tube with laser schlieren densitometry at post-shock pressures of 65, 130, and 260 Torr and post-shock temperatures of 700-1000 K. Additional experiments were conducted with iso-butyl radicals at 805 K and 8.7 bar to elucidate changes in mechanism at higher pressures. These experiments were performed in a miniature shock tube with synchrotron-based photoionization mass spectrometry. The mass spectra confirmed that scission of the O-NO bond is the primary channel by which the precursors dissociate, but they also provided evidence of a minor channel (<7.7%) through HNO loss and formation of an aldehyde. These high pressure experiments were also used to determine the disproportionation/recombination ratio for iso-butyl radicals as 0.3. Reanalysis of the lower-temperature literature and the present data yielded rate constants for the disproportionation reaction, iso-butyl + iso-butyl = iso-butene + iso-butane. A chemical kinetics model was developed for the reactions of the butyl isomers that included new paths for highly energized adducts. These adducts are formed by the addition of H, CH3 or C2H5 to the butyl radicals. Accompanying theoretical investigations show that chemically activated pathways are competitive with stabilization of the adduct by collision under the conditions of the laser schlieren experiments. These calculations also show that at 10 bar and T < 1000 K stabilization is the only important reaction, but at higher temperatures, even at 10 bar, chemically activated product channels should also be considered. Branching fractions and rate coefficients are presented for these reactions. This study also highlights the importance of the radical structure for determining branching ratios for disproportionation and recombination of alkyl radicals, and these were facilitated by theoretical calculations of recombination rate coefficients for the four butyl radical isomers. The results reveal previously unknown features of butyl radical chemistry under conditions that are relevant to a wide range of applications and reaction mechanisms are presented that incorporate pressure dependent rate coefficients for the key steps.
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Affiliation(s)
- John B Randazzo
- Chemical Sciences and Engineering Division, Argonne National Laboratory, 9700 S. Cass Avenue, Lemont, IL 60439, USA.
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28
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Feng B, Sun C, Zhao W, Zhang S. A theoretical investigation on the atmospheric degradation of the radical: reactions with NO, NO 2, and NO 3. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2020; 22:1554-1565. [PMID: 32608429 DOI: 10.1039/d0em00112k] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The radical is the key intermediate in the atmospheric oxidation of benzaldehyde, and its further chemistry contributes to local air pollution. The reaction mechanisms of the radical with NO, NO2, and NO3 were studied by quantum chemistry calculations at the CCSD(T)/CBS//M06-2X/def2-TZVP level of theory. The explicit potential energy curves were provided in order to reveal the atmospheric fate of the radical comprehensively. The main products of the reaction of with NO are predicted to be , CO2 and NO2. The reaction of with NO2 is reversible, and its main product would be C6H5C(O)O2NO2 which was predicted to be more stable than PAN (peroxyacetyl nitrate) at room temperature. The decomposition of C6H5C(O)O2NO2 at different ambient temperatures would be a potential long-range transport source of NOx in the atmosphere. The predominant products of the reaction are predicted to be C6H5C(O)O2H, C6H5C(O)OH, O2 and O3, while HO˙ is of minor importance. So, the reaction of with would be an important source of ozone and carboxylic acids in the local atmosphere, and has less contribution to the regeneration of HO˙ radicals. The reaction of with NO3 should mainly produce , CO2, O2 and NO2, which might play an important role in atmospheric chemistry of peroxy radicals at night, but has less contribution to the night-time conversion of ( and RO˙) to ( and HO˙) in the local atmosphere. The results above are in good accordance with the reported experimental observations.
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Affiliation(s)
- Bo Feng
- School of Chemistry and Chemical Engineering, Key Laboratory of Cluster Science of Ministry of Education, Beijing Institute of Technology, South Zhongguancun Street # 5, Haidian District, Beijing, 100081, P. R. China.
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29
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Medeiros DJ, Robertson SH, Blitz MA, Seakins PW. Direct Trace Fitting of Experimental Data Using the Master Equation: Testing Theory and Experiments on the OH + C 2H 4 Reaction. J Phys Chem A 2020; 124:4015-4024. [PMID: 32353235 DOI: 10.1021/acs.jpca.0c02132] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Laser flash photolysis coupled with laser-induced fluorescence observation of OH has been used to observe the equilibration of OH + C2H4 ↔ HOC2H4 over the temperature range 563-723 K and pressures of bath gas (N2) from 58 to 250 Torr. The time-resolved OH traces have been directly and globally fitted with a master equation in order to extract ΔRH00, the binding energy of the HOC2H4 adduct, with respect to reagents. The global approach allows the role that OH abstraction plays at higher temperatures to be identified. The resultant value ofΔRH00, 111.8 kJ mol-1, is determined to be better than 2 kJ mol-1 and is in agreement with our ab initio calculations (carried out at the CCSD(T)/CBS//M06-2X/aug-cc-pVTZ level), 111.4 kJ mol-1, and other state of the art calculations. Parameters for the abstraction channel are also in good agreement with previous experimental studies. To effect this analysis, the MESMER master equation code was extended to directly incorporate secondary chemistry: diffusional loss from the observation region and reaction with the photolytic precursor. These extensions, which, among other things, resolve issues related to the merging of chemically significant and internal energy relaxation eigenvalues, are presented.
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Affiliation(s)
| | - S H Robertson
- Dassault Systèmes, 334 Science Park, Milton Road, Cambridge CB4 0WN, United Kingdom
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30
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Sun H, Vaghjiani GL, Law CK. Ab Initio Kinetics of Methylamine Radical Thermal Decomposition and H-Abstraction from Monomethylhydrazine by H-Atom. J Phys Chem A 2020; 124:3747-3753. [PMID: 32299215 DOI: 10.1021/acs.jpca.0c02389] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Methylamine radicals (CH3NH) and amino radicals (NH2) are major products in the early pyrolysis/ignition of monomethylhydrazine (CH3NHNH2). Ab initio kinetics of thermal decomposition of CH3NH radicals was analyzed by RRKM master equation simulations. It was found that β-scission of the methyl H-atom from CH3NH radicals is predominant and fast enough to induce subsequent H-abstraction reactions in CH3NHNH2 to trigger ignition. Consequently, the kinetics of H-abstraction reactions from CH3NHNH2 by H-atoms was further investigated. It was found that the energy barriers for abstraction of the central amine H-atom, two terminal amine H-atoms, and methyl H-atoms are 4.16, 2.95, 5.98, and 8.50 kcal mol-1, respectively. In units of cm3 molecule-1 s-1, the corresponding rate coefficients were found to be k8 = 9.63 × 10-20T2.596 exp(-154.2/T), k9 = 2.04 × 10-18T2.154 exp(104.1/T), k10 = 1.13 × 10-20T2.866 exp(-416.3/T), and k11 = 2.41 × 10-23T3.650 exp(-870.5/T), respectively, in the 290-2500 K temperature range. The results reveal that abstraction of the terminal amine H-atom to form trans-CH3NHNH radicals is the dominant channel among the different abstraction channels. At 298 K, the total theoretical H-abstraction rate coefficient, calculated with no adjustable parameters, is 8.16 × 10-13 cm3 molecule-1 s-1, which is in excellent agreement with Vaghjiani's experimental observation of (7.60 ± 1.14) × 10-13 cm3 molecule-1 s-1 ( J. Phys. Chem. A 1997, 101, 4167-4171, DOI: 10.1021/jp964044z).
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Affiliation(s)
- Hongyan Sun
- In-Space Propulsion Branch, Rocket Propulsion Division, Aerospace Systems Directorate, Air Force Research Laboratory, AFRL/RQRS, Edwards Air Force Base, California 93524, United States
| | - Ghanshyam L Vaghjiani
- In-Space Propulsion Branch, Rocket Propulsion Division, Aerospace Systems Directorate, Air Force Research Laboratory, AFRL/RQRS, Edwards Air Force Base, California 93524, United States
| | - Chung K Law
- Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, New Jersey 08544, United States
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31
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Mai TV, Lin KC, Huynh LK. Thermal unimolecular decomposition of ethyl 2‐furoate and its reactivity toward OH radicals: A theoretical study. INT J CHEM KINET 2020. [DOI: 10.1002/kin.21371] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- Tam V.‐T. Mai
- University of ScienceHo Chi Minh City Vietnam
- Vietnam National UniversityHo Chi Minh City Vietnam
- Molecular Science and Nano‐Materials LabInstitute for Computational Science and TechnologyHo Chi Minh City Vietnam
| | - Kuang C. Lin
- Department of Engineering and System ScienceNational Tsing Hua UniversityHsinchu City Taiwan
| | - Lam K. Huynh
- Vietnam National UniversityHo Chi Minh City Vietnam
- International UniversityHo Chi Minh City Vietnam
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32
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Mai TVT, Nguyen HT, Huynh LK. Atmospheric chemistry of the reaction between propylene carbonate and OH radical: An ab initio RRKM-based master equation study. Chem Phys Lett 2020. [DOI: 10.1016/j.cplett.2019.137020] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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33
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Sun Y, Zhou CW, Somers KP, Curran HJ. Ab Initio/Transition-State Theory Study of the Reactions of Ċ 5H 9 Species of Relevance to 1,3-Pentadiene, Part I: Potential Energy Surfaces, Thermochemistry, and High-Pressure Limiting Rate Constants. J Phys Chem A 2019; 123:9019-9052. [PMID: 31566374 DOI: 10.1021/acs.jpca.9b06628] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
In this study, the reactions of Ċ5H9 radicals are theoretically investigated, with a particular emphasis on hydrogen atom addition reactions to 1,3-pentadiene (C5H8) to form Ċ5H9 radicals, although the subsequent isomerization and decomposition reactions of the Ċ5H9 radicals are also of direct relevance to the radicals formed from the pyrolysis and oxidation of species including pentene and cyclopentane. Moreover, H-atom abstraction reactions by hydrogen atoms from 1,3-pentadiene are also investigated. The geometries and frequencies of 63 potential energy surface (PES) minima and 88 transition states are optimized at the ωB97XD/aug-cc-pVTZ level of theory. Spin-unrestricted open-shell single-point energies for all the species are calculated at the CCSD(T)/aug-cc-pVTZ level of theory with basis set corrections from MP2/aug-cc-pVXZ (where X = T and Q). A one-dimensional hindered rotor treatment is employed for torsional modes, with the M06-2X/6-311++G(D,P) method used to compute the potential energy as a function of the dihedral angle. The high-pressure limiting rate constants and the thermochemical properties for C5 species are calculated using the Master Equation System Solver (MESS) with conventional transition-state theory and comparisons made with existing available literature data. A hydrogen atom can add to the terminal carbon atom of 1,3-pentadiene to form the 2,4-Ċ5H9 radical and/or the internal carbon atoms to form 2,5-Ċ5H9, 1,4-Ċ5H9, and 1,3-Ċ5H9 radicals. Among the four entrance channels for Ḣ atom addition reactions, the formation of 2,4-Ċ5H9 and 1,3-Ċ5H9 radicals is more exothermic in comparison to the other Ċ5H9 isomers (2,5-Ċ5H9, 1,4-Ċ5H9) because of the resonantly stabilized allylic structure. Consequently, the formation of the former is generally dominant in terms of barrier heights. Ḣ atom addition reactions to 1,3-pentadiene are compared to available C3-C5 alkenes and dienes, with external addition calculated to be kinetically favored over internal addition. However, the correlation between heats of formation and energy barriers for Ḣ atom addition to 1,2-dienes is different from that for 1,3- and 1,4-dienes. Hydrogen atom addition and abstraction rate constants are also compared for 1,3-pentadiene, with addition found to be dominant. The subsequent unimolecular reactions on the Ċ5H9 PES are found to be highly complex with reactions taking place on a multiple-well multiple-channel PES. For clarity, the reaction mechanism and kinetics of each Ċ5H9 radical are discussed individually in terms of the computed enthalpy of the reaction and activation, the transition-state structure/reaction class, and also in terms of the combustion species for which the reactions are of potential importance. The reactions on the Ċ5H9 PES are divided into three reaction classes (H-shift isomerization, cycloaddition, and β-scission reactions), and the reactivity-structure-based estimation rules for energy barriers are derived for these three reaction classes and compared to literature results for alkyl radicals.
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Affiliation(s)
- Yanjin Sun
- Combustion Chemistry Centre, School of Chemistry, Martin Ryan Institute MaREI , National University of Ireland , Galway H91 TK33 , Ireland
| | - Chong-Wen Zhou
- Combustion Chemistry Centre, School of Chemistry, Martin Ryan Institute MaREI , National University of Ireland , Galway H91 TK33 , Ireland.,School of Energy and Power Engineering , Beihang University , Beijing 100191 , P. R. China
| | - Kieran P Somers
- Combustion Chemistry Centre, School of Chemistry, Martin Ryan Institute MaREI , National University of Ireland , Galway H91 TK33 , Ireland
| | - Henry J Curran
- Combustion Chemistry Centre, School of Chemistry, Martin Ryan Institute MaREI , National University of Ireland , Galway H91 TK33 , Ireland
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34
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Zádor J, Miller JA. Comment on "Influence of Multiple Conformations and Paths on Rate Constants and Product Branching Ratios. Thermal Decomposition of 1-Propanol Radicals". J Phys Chem A 2019; 123:1129-1130. [PMID: 30644751 DOI: 10.1021/acs.jpca.8b12016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Judit Zádor
- Combustion Research Facility, MS 9055 , Sandia National Laboratories , Livermore , California 94551-0969 , United States
| | - James A Miller
- Chemical Sciences and Engineering Division , Argonne National Laboratory , Argonne , Illinois 60439 , United States
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Gnanaprakasam M, Sandhiya L, Senthilkumar K. Mechanism and kinetics of the oxidation of dimethyl carbonate by hydroxyl radical in the atmosphere. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2019; 26:3357-3367. [PMID: 30511221 DOI: 10.1007/s11356-018-3831-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Accepted: 11/22/2018] [Indexed: 06/09/2023]
Abstract
The mechanism and kinetics for the reaction of dimethyl carbonate (DMC) with OH radical have been studied by using quantum chemical methods. Four reaction pathways were identified for the initial reaction. In the first two pathways, hydrogen atom abstraction is taking place and alkyl radical intermediate is formed with the energy barrier of 6.4 and 7.9 kcal/mol. In the third pathway, OH addition reaction to the carbonyl carbon (C2) atom of DMC and intermediate, I2, is formed with an energy barrier of 11.9 kcal/mol. In the fourth pathway, along with CH3O●, methyl hydrogen carbonate is formed. For this C-O bond breaking and O-H addition reaction, the energy barrier is 27 kcal/mol. The calculated enthalpy and Gibbs energy values show that the studied initial reactions are exothermic and exoergic except the OH addition reaction. For the initial reactions, the rate constants were calculated by using canonical variational transition state theory (CVT) with small curvature tunneling (SCT) correction over the temperature range of 278-1200 K. At 298 K, the calculated rate coefficient for the in-plane and out-of-plane hydrogen atom abstraction reaction pathway is 2.30 × 10-13 and 0.02 × 10-13 cm3 molecule-1 s-1. Further, the reaction between alkyl radical intermediate formed from the first pathway and O2 is studied. The reaction of alkyl peroxy radical intermediate with atmospheric oxidants, HO2, NO, and NO2 is also studied. It was found that the formic (methyl carbonic) anhydride is the end product formed from the atmospheric oxidation and secondary reactions of DMC.
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Affiliation(s)
| | - Lakshmanan Sandhiya
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX, USA
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36
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Sun C, Xu B, Lv L, Zhang S. Theoretical investigation on the reaction mechanism and kinetics of a Criegee intermediate with ethylene and acetylene. Phys Chem Chem Phys 2019; 21:16583-16590. [DOI: 10.1039/c9cp02644d] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The competition among the possible pathways, the branching ratios of the adduct and the decomposition products at different temperatures and pressures have been evaluated.
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Affiliation(s)
- Cuihong Sun
- College of Chemical Engineering
- Shijiazhuang University
- Shijiazhuang
- P. R. China
| | - Baoen Xu
- College of Chemical Engineering
- Shijiazhuang University
- Shijiazhuang
- P. R. China
| | - Liqiang Lv
- College of Chemical Engineering
- Shijiazhuang University
- Shijiazhuang
- P. R. China
| | - Shaowen Zhang
- School of Chemistry and Chemical Engineering
- Key Laboratory of Cluster Science of Ministry of Education
- Beijing Institute of Technology
- South Zhongguancun Street #5
- Beijing
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37
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Abstract
This work presents a detailed investigation into the isomerization and decomposition of HONO and HNO2.
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Affiliation(s)
- Xi Chen
- Department of Chemistry
- Brown University
- Providence
- USA
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38
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Chu TC, Buras ZJ, Oßwald P, Liu M, Goldman MJ, Green WH. Modeling of aromatics formation in fuel-rich methane oxy-combustion with an automatically generated pressure-dependent mechanism. Phys Chem Chem Phys 2019; 21:813-832. [DOI: 10.1039/c8cp06097e] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
An automatic generated mechanism for methane-rich combustion captures the chemistry from small molecules to three-ring aromatic species.
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Affiliation(s)
- Te-Chun Chu
- Massachusetts Institute of Technology
- Cambridge
- USA
| | | | - Patrick Oßwald
- Institute of Combustion Technology
- German Aerospace Center (DLR)
- D-70569 Stuttgart
- Germany
| | - Mengjie Liu
- Massachusetts Institute of Technology
- Cambridge
- USA
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39
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Sun C, Zhang S, Yue J, Zhang S. Theoretical Study on the Reaction Mechanism and Kinetics of Criegee Intermediate CH2OO with Acrolein. J Phys Chem A 2018; 122:8729-8737. [DOI: 10.1021/acs.jpca.8b06897] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Cuihong Sun
- College of Chemical Engineering, Shijiazhuang University, Shijiazhuang, 050035, P. R. China
- School of Chemistry and Chemical Engineering, Key Laboratory of Cluster Science of Ministry of Education, Beijing Institute of Technology, Beijing 100081, P. R. China
| | - Shaoyan Zhang
- College of Chemical Engineering, Shijiazhuang University, Shijiazhuang, 050035, P. R. China
| | - Junyong Yue
- School of Literature and Media, Shijiazhuang University, Shijiazhuang 050035, P. R. China
| | - Shaowen Zhang
- School of Chemistry and Chemical Engineering, Key Laboratory of Cluster Science of Ministry of Education, Beijing Institute of Technology, Beijing 100081, P. R. China
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40
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Yao Q, Cao XM, Zong WG, Sun XH, Li ZR, Li XY. Potential Energy Surface for Large Barrierless Reaction Systems: Application to the Kinetic Calculations of the Dissociation of Alkanes and the Reverse Recombination Reactions. J Phys Chem A 2018; 122:4869-4881. [PMID: 29757648 DOI: 10.1021/acs.jpca.8b00877] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The isodesmic reaction method is applied to calculate the potential energy surface (PES) along the reaction coordinates and the rate constants of the barrierless reactions for unimolecular dissociation reactions of alkanes to form two alkyl radicals and their reverse recombination reactions. The reaction class is divided into 10 subclasses depending upon the type of carbon atoms in the reaction centers. A correction scheme based on isodesmic reaction theory is proposed to correct the PESs at UB3LYP/6-31+G(d,p) level. To validate the accuracy of this scheme, a comparison of the PESs at B3LYP level and the corrected PESs with the PESs at CASPT2/aug-cc-pVTZ level is performed for 13 representative reactions, and it is found that the deviations of the PESs at B3LYP level are up to 35.18 kcal/mol and are reduced to within 2 kcal/mol after correction, indicating that the PESs for barrierless reactions in a subclass can be calculated meaningfully accurately at a low level of ab initio method using our correction scheme. High-pressure limit rate constants and pressure dependent rate constants of these reactions are calculated based on their corrected PESs and the results show the pressure dependence of the rate constants cannot be ignored, especially at high temperatures. Furthermore, the impact of molecular size on the pressure-dependent rate constants of decomposition reactions of alkanes and their reverse reactions has been studied. The present work provides an effective method to generate meaningfully accurate PESs for large molecular system.
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41
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Ghaderi N. Bimolecular Master Equations for a Single and Multiple Potential Wells with Analytic Solutions. J Phys Chem A 2018; 122:3506-3534. [DOI: 10.1021/acs.jpca.7b09244] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Nima Ghaderi
- Department of Physics, Beckman Institute, and Noyes Laboratory of Chemical Physics, California Institute of Technology, 1200 East California Boulevard, Pasadena, California 91125, United States
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42
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Affiliation(s)
- Jeffrey A. Manion
- Chemical Sciences Division; National Institute of Standards and Technology; Gaithersburg MD 20899-8320
| | - Iftikhar A. Awan
- Chemical Sciences Division; National Institute of Standards and Technology; Gaithersburg MD 20899-8320
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43
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Shannon R, Glowacki DR. A Simple “Boxed Molecular Kinetics” Approach To Accelerate Rare Events in the Stochastic Kinetic Master Equation. J Phys Chem A 2018; 122:1531-1541. [DOI: 10.1021/acs.jpca.7b12521] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Robin Shannon
- Mechanical Engineering, Stanford University, Stanford, California 94305, United States
- School of Chemistry, University of Bristol, Bristol, BS8 1TS, United Kingdom
| | - David R. Glowacki
- Mechanical Engineering, Stanford University, Stanford, California 94305, United States
- School of Chemistry, University of Bristol, Bristol, BS8 1TS, United Kingdom
- Department of Computer Science, University of Bristol, Bristol, BS8 1UB, United Kingdom
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44
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Winiberg FAF, Percival CJ, Shannon R, Khan MAH, Shallcross DE, Liu Y, Sander SP. Reaction kinetics of OH + HNO3 under conditions relevant to the upper troposphere/lower stratosphere. Phys Chem Chem Phys 2018; 20:24652-24664. [DOI: 10.1039/c8cp04193h] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Key upper atmosphere reaction of HNO3 + OH studied over extended pressure and temperature range using new alternative detection method.
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Affiliation(s)
| | - Carl J. Percival
- NASA Jet Propulsion Laboratory
- California Institute of Technology
- Pasadena
- USA
| | - Robin Shannon
- School of Chemistry
- Cantock's Close
- University of Bristol
- Bristol
- UK
| | - M. Anwar H. Khan
- School of Chemistry
- Cantock's Close
- University of Bristol
- Bristol
- UK
| | | | - Yingdi Liu
- NASA Jet Propulsion Laboratory
- California Institute of Technology
- Pasadena
- USA
| | - Stanley P. Sander
- NASA Jet Propulsion Laboratory
- California Institute of Technology
- Pasadena
- USA
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45
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Winter PM, Rheaume M, Cooksy AL. RRKM and master equation kinetic analysis of parallel addition reactions of isomeric radical intermediates in hydrocarbon flames. J Chem Phys 2017; 147:054306. [DOI: 10.1063/1.4996557] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Pierre M. Winter
- Department of Chemistry and Biochemistry, San Diego State University, 5500 Campanile Drive, San Diego, California 92182-1030, USA
| | - Michael Rheaume
- Department of Chemistry and Biochemistry, San Diego State University, 5500 Campanile Drive, San Diego, California 92182-1030, USA
| | - Andrew L. Cooksy
- Department of Chemistry and Biochemistry, San Diego State University, 5500 Campanile Drive, San Diego, California 92182-1030, USA
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46
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Lockhart JPA, Goldsmith CF, Randazzo JB, Ruscic B, Tranter RS. An Experimental and Theoretical Study of the Thermal Decomposition of C4H6 Isomers. J Phys Chem A 2017; 121:3827-3850. [PMID: 28440652 DOI: 10.1021/acs.jpca.7b01186] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- James P. A. Lockhart
- Chemical
Sciences and Engineering Division, Argonne National Laboratory, Argonne, Illinois, United States
| | | | - John B. Randazzo
- Chemical
Sciences and Engineering Division, Argonne National Laboratory, Argonne, Illinois, United States
| | - Branko Ruscic
- Chemical
Sciences and Engineering Division, Argonne National Laboratory, Argonne, Illinois, United States
- Computation
Institute, The University of Chicago, Chicago, Illinois, United States
| | - Robert S. Tranter
- Chemical
Sciences and Engineering Division, Argonne National Laboratory, Argonne, Illinois, United States
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47
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Sumiya Y, Taketsugu T, Maeda S. Full rate constant matrix contraction method for obtaining branching ratio of unimolecular decomposition. J Comput Chem 2016; 38:101-109. [PMID: 27796079 DOI: 10.1002/jcc.24526] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2016] [Revised: 10/05/2016] [Accepted: 10/12/2016] [Indexed: 11/06/2022]
Abstract
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 C3 H5 and C4 H5 . 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 C4 H5 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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Affiliation(s)
- Yosuke Sumiya
- Graduate School of Chemical Sciences and Engineering, Hokkaido University, Kita-ku, Sapporo, 060-8628, Japan
| | - Tetsuya Taketsugu
- Department of Chemistry, Faculty of Science, Hokkaido University, Kita-ku, Sapporo, 060-0810, Japan
| | - Satoshi Maeda
- Department of Chemistry, Faculty of Science, Hokkaido University, Kita-ku, Sapporo, 060-0810, Japan
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48
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Knezz SN, Waltz TA, Haenni BC, Burrmann NJ, McMahon RJ. Spectroscopy and Photochemistry of Triplet 1,3-Dimethylpropynylidene (MeC3Me). J Am Chem Soc 2016; 138:12596-604. [PMID: 27640734 DOI: 10.1021/jacs.6b07444] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Photolysis (λ > 472 nm) of 2-diazo-3-pentyne (11) affords triplet 1,3-dimethylpropynylidene (MeC3Me, (3)3), which was characterized spectroscopically in cryogenic matrices. The infrared, electronic absorption, and electron paramagnetic resonance spectra of MeC3Me ((3)3) are compared with those of the parent system (HC3H) to ascertain the effect of alkyl substituents on delocalized carbon chains of this type. Quantum chemical calculations (CCSD(T)/ANO1) predict an unsymmetrical equilibrium structure for triplet MeC3Me ((3)3), but they also reveal a very shallow potential energy surface. The experimental IR spectrum of triplet MeC3Me ((3)3) is best interpreted in terms of a quasilinear, axially symmetric structure. EPR spectra yield zero-field splitting parameters that are typical for triplet carbenes with axial symmetry (|D/hc| = 0.63 cm(-1), |E/hc| = ∼ 0 cm(-1)), while theoretical analysis suggests that the methyl substituents confer significant spin polarization to the carbon chain. Upon irradiation into the near-UV electronic absorption (λmax 350 nm), MeC3Me ((3)3) undergoes 1,2-hydrogen migration to yield pent-1-en-3-yne (4), a photochemical reaction that is typical of carbenes bearing a methyl substituent. This facile process apparently precludes photoisomerization to other interesting C5H6 isomers, in contrast to the rich photochemistry of the parent C3H2 system.
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Affiliation(s)
- Stephanie N Knezz
- Department of Chemistry, University of Wisconsin-Madison , 1101 University Avenue, Madison, Wisconsin 53706-1322, United States
| | - Terese A Waltz
- Department of Chemistry, University of Wisconsin-Madison , 1101 University Avenue, Madison, Wisconsin 53706-1322, United States
| | - Benjamin C Haenni
- Department of Chemistry, University of Wisconsin-Madison , 1101 University Avenue, Madison, Wisconsin 53706-1322, United States
| | - Nicola J Burrmann
- Department of Chemistry, University of Wisconsin-Madison , 1101 University Avenue, Madison, Wisconsin 53706-1322, United States
| | - Robert J McMahon
- Department of Chemistry, University of Wisconsin-Madison , 1101 University Avenue, Madison, Wisconsin 53706-1322, United States
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49
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Hickson KM, Wakelam V, Loison JC. Methylacetylene (CH3CCH) and propene (C3H6) formation in cold dense clouds: A case of dust grain chemistry. ACTA ACUST UNITED AC 2016. [DOI: 10.1016/j.molap.2016.03.001] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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50
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Sun C, Lv L, Zhang S. Theoretical investigation on the reaction mechanism and kinetics of benzyl alcohol with OH radical. Theor Chem Acc 2016. [DOI: 10.1007/s00214-016-1811-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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