1
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Etz BD, Woodley CM, Shukla MK. Reaction mechanisms for methyl isocyanate (CH 3NCO) gas-phase degradation. JOURNAL OF HAZARDOUS MATERIALS 2024; 473:134628. [PMID: 38795480 DOI: 10.1016/j.jhazmat.2024.134628] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2024] [Revised: 05/04/2024] [Accepted: 05/14/2024] [Indexed: 05/28/2024]
Abstract
Methyl isocyanate (MIC) is a toxic chemical found in many commercial, industrial, and agricultural processes, and was the primary chemical involved in the Bhopal, India disaster of 1984. The atmospheric environmental chemical reactivity of MIC is relatively unknown with only proposed reaction channels, mainly involving OH-initiated reactions. The gas-phase degradation reaction pathways of MIC and its primary product, formyl isocyanate (FIC), were investigated with quantum mechanical (QM) calculations to assess the fate of the toxic chemical and its primary transformation products. Transition state energy barriers and reaction energetics were evaluated for thermolysis/pyrolysis-like reactions and bimolecular reactions initiated by relevant radicals (•OH and Cl•) to evaluate the potential energy surfaces and identify the primary reaction pathways and products. Thermolysis/pyrolysis of MIC requires high energy to initiate N-CH3 and C-H bond dissociation and is unlikely to dissociate except under extreme conditions. Bimolecular radical addition and H-abstraction reaction pathways are deemed the most kinetically and thermodynamically favorable mechanisms. The primary transformation products of MIC were identified as FIC, methylcarbamic acid, isocyanic acid (isocyanate radical), and carbon dioxide. The results of this work inform the gas-phase reaction channels of MIC and FIC reactivity and identify transformation products under various reaction conditions.
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Affiliation(s)
- Brian D Etz
- Oak Ridge Institute for Science and Education (ORISE), Oak Ridge, TN 37830, USA
| | - Christa M Woodley
- Environmental Laboratory, US Army Engineer Research and Development Center, 3909 Halls Ferry Road, Vicksburg, MS 39180, USA
| | - Manoj K Shukla
- Environmental Laboratory, US Army Engineer Research and Development Center, 3909 Halls Ferry Road, Vicksburg, MS 39180, USA.
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2
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Abeywardane K, Goldsmith CF. Accurate Enthalpies of Formation for PFAS from First-Principles: Combining Different Levels of Theory in a Generalized Thermochemical Hierarchy. ACS PHYSICAL CHEMISTRY AU 2024; 4:247-258. [PMID: 38800729 PMCID: PMC11117692 DOI: 10.1021/acsphyschemau.3c00056] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/25/2023] [Revised: 01/05/2024] [Accepted: 01/08/2024] [Indexed: 05/29/2024]
Abstract
The enthalpies of formation are computed for a large number of per- and poly fluoroalkyl substances (PFAS) using a connectivity-based hierarchy (CBH) approach. A combination of different electronic structure methods are used to provide the reference data in a hierarchical manner. The ANL0 method, in conjunction with the active thermochemical tables, provides enthalpies of formation for smaller species with subchemical accuracy. Coupled-cluster theory with explicit correlations are used to compute enthalpies of formation for intermediate species, based upon the ANL0 results. For the largest PFAS, including perfluorooctanoic acid (PFOA) and heptafluoropropylene oxide dimer acid (GenX), coupled-cluster theory with local correlations is used. The sequence of homodesmotic reactions proposed by the CBH are determined automatically by a new open-source code, AutoCBH. The results are the first reported enthalpies of formation for the majority of the species. A convergence analysis and global uncertainty quantification confirm that the enthalpies of formation at 0 K should be accurate to within ±5 kJ/mol. This new approach is not limited to PFAS, but can be applied to many chemical systems.
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Affiliation(s)
- Kento Abeywardane
- Chemical Engineering Group, School
of Engineering, Brown University, Providence, Rhode Island 02912, United States
| | - C. Franklin Goldsmith
- Chemical Engineering Group, School
of Engineering, Brown University, Providence, Rhode Island 02912, United States
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3
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Pang HW, Dong X, Johnson MS, Green WH. Subgraph Isomorphic Decision Tree to Predict Radical Thermochemistry with Bounded Uncertainty Estimation. J Phys Chem A 2024; 128:2891-2907. [PMID: 38536892 DOI: 10.1021/acs.jpca.4c00569] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/12/2024]
Abstract
Detailed chemical kinetic models offer valuable mechanistic insights into industrial applications. Automatic generation of reliable kinetic models requires fast and accurate radical thermochemistry estimation. Kineticists often prefer hydrogen bond increment (HBI) corrections from a closed-shell molecule to the corresponding radical for their interpretability, physical meaning, and facilitation of error cancellation as a relative quantity. Tree estimators, used due to limited data, currently rely on expert knowledge and manual construction, posing challenges in maintenance and improvement. In this work, we extend the subgraph isomorphic decision tree (SIDT) algorithm originally developed for rate estimation to estimate HBI corrections. We introduce a physics-aware splitting criterion, explore a bounded weighted uncertainty estimation method, and evaluate aleatoric uncertainty-based and model variance reduction-based prepruning methods. Moreover, we compile a data set of thermochemical parameters for 2210 radicals involving C, O, N, and H based on quantum chemical calculations from recently published works. We leverage the collected data set to train the SIDT model. Compared to existing empirical tree estimators, the SIDT model (1) offers an automatic approach to generating and extending the tree estimator for thermochemistry, (2) has better accuracy and R2, (3) provides significantly more realistic uncertainty estimates, and (4) has a tree structure much more advantageous in descent speed. Overall, the SIDT estimator marks a great leap in kinetic modeling, offering more precise, reliable, and scalable predictions for radical thermochemistry.
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Affiliation(s)
- Hao-Wei Pang
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Xiaorui Dong
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Matthew S Johnson
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - William H Green
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
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4
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Ram H, Sadej TP, Murphy CC, Mallo TJ, Westmoreland PR. Thermochemistry of Species in Gas-Phase Thermal Oxidation of C 2 to C 8 Perfluorinated Carboxylic Acids. J Phys Chem A 2024; 128:1313-1326. [PMID: 38335280 DOI: 10.1021/acs.jpca.3c06937] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/12/2024]
Abstract
New thermochemical properties, Cp°(T), H°(T), S°(T), and G°(T), are predicted for 123 species involved in the thermal destruction of perfluorinated carboxylic acids (PFCAs) using computational quantum chemistry and ideal-gas statistical mechanics. Relevant species were identified from the development of mechanisms for the pyrolysis and oxidation of PFCAs of C2 to C8 in length. Partition functions were obtained from the results of calculations at the G4 level for species up to C4 in length and M06-2X-D3(0)/def2-QZVPP for species C5 to C8 in length. The 1D hindered-rotor approximation was used to correct for torsional modes in the larger species. Ideal-gas thermochemistry was computed and fitted to 7-parameter NASA polynomials over a 200-2500 K temperature range, and the data are provided in standardized format. To gauge the effects of both method and basis set choice, enthalpies of formation at 0 K are calculated from various other density functionals (including B3LYP and ωB97XD), basis sets, and composite model chemistries (CBS-QB3). They are benchmarked against data from the Active Thermochemical Tables, high-level ANL0 calculations from the literature, and G4 calculations from this work. The effects of internal rotations and other anharmonicities are discussed, and bond dissociation energies and reaction equilibria provide mechanistic insights.
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Affiliation(s)
- Hrishikesh Ram
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina 27606, United States
| | - Thomas P Sadej
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina 27606, United States
| | - C Claire Murphy
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina 27606, United States
| | - Tim J Mallo
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina 27606, United States
| | - Phillip R Westmoreland
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina 27606, United States
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5
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Al-Kwradi M, Ali L, Altarawneh M. Predicting the Decomposition Mechanism of the Serine α-Amino Acid in the Gas Phase and Condensed Media. ACS OMEGA 2024; 9:8574-8584. [PMID: 38405454 PMCID: PMC10882666 DOI: 10.1021/acsomega.3c10496] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/29/2023] [Revised: 01/16/2024] [Accepted: 01/22/2024] [Indexed: 02/27/2024]
Abstract
Comprehending the nitrogen combustion chemistry during the thermal treatment of biomass demands acquiring a detailed mechanism for reaction pathways that dictate the degradation of amino acids. Serine (Ser) is an important α-amino acid that invariably exists in various categories of biomass, most notably algae. Based on density functional theory (DFT) coupled with kinetic modeling, this study presents a mechanistic overview of reactions that govern the fragmentation of the Ser compound in the gas phase as well as in the crystalline form. Thermokinetic parameters are computed for a large set of reactions and involved species. The initial decomposition of Ser is solely controlled by a dehydration channel that leads to the formation of a 2-aminoacrylic acid molecule. Decarboxylation and deamination routes are likely to be of negligible importance. The falloff window of the dehydration channel extends until the atmospheric pressure. Bimolecular reactions between two Ser compounds simulate the widely discussed cross-linking reactions that prevail in the condensed medium. It is demonstrated that the formation of the key experimentally observed products (NH3, CO2, and CO) may originate from direct bond fissions in the melted phase of Ser prior to evaporation. A constructed kinetic model (with 24 reactions) accounts for the primary steps in the degradation of the Ser molecule in the gas phase. These steps include dehydration, decarboxylation, deamination, and others. The kinetic model presents an onset decomposition temperature of 700 K with the complete conversion attained at ∼1090 K. Likewise, the model portrays the temperature-dependent increasing yields of CO2 and NH3. The results presented in this work offer a detailed analysis of the intricate chemical processes involved in nitrogen transformations, specifically in relation to amino acids. Amino acids play a crucial role as the primary nitrogen carriers in biomass, such as microalgae and protein-rich biomass.
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Affiliation(s)
- Mubarak Al-Kwradi
- Department of Chemical and Petroleum Engineering, United Arab Emirates University,, Sheikh Khalifa bin Zayed Street, Al-Ain 15551, United Arab Emirates
| | - Labeeb Ali
- Department of Chemical and Petroleum Engineering, United Arab Emirates University,, Sheikh Khalifa bin Zayed Street, Al-Ain 15551, United Arab Emirates
| | - Mohammednoor Altarawneh
- Department of Chemical and Petroleum Engineering, United Arab Emirates University,, Sheikh Khalifa bin Zayed Street, Al-Ain 15551, United Arab Emirates
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6
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Guo J, Tan N, Chen L, Tang S, Tang A. Reactions of Ethynyloxy Radical with Hydroperoxyl Radical: Bridging Theoretical Reaction Dynamics and Chemical Modeling of Combustion. Chemphyschem 2024; 25:e202300515. [PMID: 37991746 DOI: 10.1002/cphc.202300515] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2023] [Revised: 11/20/2023] [Accepted: 11/20/2023] [Indexed: 11/23/2023]
Abstract
A detailed and accurate combustion reaction mechanism is crucial for understanding the nature of fuel combustion. In this work, a theoretical study of reaction HCCO+HO2 using M06-2X/6-311++G(d,p) for geometry optimization and combined methods based on spin-unrestricted CCSD(T)/CBS level of theory with basis set extrapolation from MP2/aug-cc-pVnZ (n=T and Q) for energy calculations were performed. The temperature- and pressure-dependent rate coefficients at 300-2000 K and 0.01-100 atm, suitable for combustion conditions, were derived using the Rice-Ramsberger-Kassel-Marcus/Master-Equation approach. Furthermore, temperature-dependent thermochemistry data of key species for the HCCO+HO2 system has also been studied. Finally, an updated ketene model is developed by supplementing the most recent theoretical work and the theoretical work in this paper. This updated model was tested to simulate the speciation of ketene oxidation in available experimental research. It is shown that the updated model for predicting ketene oxidation exhibits a high level of agreement with experimental data across a wide range of species profiles. An analysis was conducted to identify the crucial reactions that influence ketene ignition. This paper's research findings are essential for enhancing the combustion mechanism of ketene and other hydrocarbons and oxygenated hydrocarbon fuels.
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Affiliation(s)
- Junjiang Guo
- School of Chemical Engineering, Guizhou Institute of Technology, Guiyang, Guizhou, 550003, P. R. China
- Guizhou Provincial Key Laboratory of Energy Chemistry, Guizhou Institute of Technology, Guiyang, Guizhou, 550003, P. R. China
| | - Ningxin Tan
- School of Chemical Engineering, Sichuan University, Chengdu, Sichuan, 610065, P. R. China
| | - Lijun Chen
- School of Chemical Engineering, Guizhou Institute of Technology, Guiyang, Guizhou, 550003, P. R. China
- Guizhou Provincial Key Laboratory of Energy Chemistry, Guizhou Institute of Technology, Guiyang, Guizhou, 550003, P. R. China
| | - Shiyun Tang
- School of Chemical Engineering, Guizhou Institute of Technology, Guiyang, Guizhou, 550003, P. R. China
- Guizhou Provincial Key Laboratory of Energy Chemistry, Guizhou Institute of Technology, Guiyang, Guizhou, 550003, P. R. China
| | - Anjiang Tang
- School of Chemical Engineering, Guizhou Institute of Technology, Guiyang, Guizhou, 550003, P. R. China
- Guizhou Provincial Key Laboratory of Energy Chemistry, Guizhou Institute of Technology, Guiyang, Guizhou, 550003, P. R. China
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7
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Sepulveda-Montaño LX, Galindo JF, Kuroda DG. Infrared Spectroscopy of Liquid Solutions as a Benchmarking Tool of Semiempirical QM Methods: The Case of GFN2-xTB. J Phys Chem B 2023; 127:7955-7963. [PMID: 37676972 DOI: 10.1021/acs.jpcb.3c03174] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/09/2023]
Abstract
The accurate description of large molecular systems has triggered the development of new computational methods. Due to the computational cost of modeling large systems, the methods usually require a trade-off between accuracy and speed. Therefore, benchmarking to test the accuracy and precision of the method is an important step in their development. The typical gold standard for evaluating these methods is isolated molecules, because of the low computational cost. However, the advent of high-performance computing has made it possible to benchmark computational methods using observables from more complex systems such as liquid solutions. To this end, infrared spectroscopy provides a suitable set of observables (i.e., vibrational transitions) for liquid systems. Here, IR spectroscopy observables are used to benchmark the predictions of the newly developed GFN2-xTB semiempirical method. Three different IR probes (i.e., N-methylacetamide, benzonitrile, and semiheavy water) in solution are selected for this purpose. The work presented here shows that GFN2-xTB predicts central frequencies with errors of less than 10% in all probes. In addition, the method captures detailed properties of the molecular environment such as weak interactions. Finally, the GFN2-xTB correctly assesses the vibrational solvatochromism for N-methylacetamide and semiheavy water but does not have the accuracy needed to properly describe benzonitrile. Overall, the results indicate not only that GFN2-xTB can be used to predict the central frequencies and their dependence on the molecular environment with reasonable accuracy but also that IR spectroscopy data of liquid solutions provide a suitable set of observables for the benchmarking of computational methods.
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Affiliation(s)
| | - Johan Fabian Galindo
- Department of Chemistry, Universidad Nacional de Colombia sede Bogotá, 111321 Bogotá, Colombia
| | - Daniel G Kuroda
- Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803, United States
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8
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Lemler PM, Craft CL, Pollok CH, Regan TP, Vaccaro PH. Isolated and solvated chiroptical behavior in conformationally flexible butanamines. Chirality 2023; 35:586-618. [PMID: 37550220 DOI: 10.1002/chir.23570] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2023] [Revised: 04/15/2023] [Accepted: 04/17/2023] [Indexed: 08/09/2023]
Abstract
The nonresonant optical activity of two highly flexible aliphatic amines, (2R)-3-methyl-2-butanamine (R-MBA) and (2R)-(3,3)-dimethyl-2-butanamine (R-DMBA), has been probed under isolated and solvated conditions to examine the roles of conformational isomerism and to explore the influence of extrinsic perturbations. The optical rotatory dispersion (ORD) measured in six solvents presented uniformly negative rotatory powers over the 320-590 nm region, with the long-wavelength magnitude of chiroptical response growing nearly monotonically as the dielectric constant of the surroundings diminished. The intrinsic specific optical rotation,α λ T (in deg dm-1 [g/mL]-1 ), extracted for ambient vapor-phase samples of R-MBA [-11.031(98) and -2.29 (11)] and R-DMBA [-9.434 (72) and -1.350 (48)] at 355 and 633 nm were best reproduced by counterintuitive solvents of high polarity (yet low polarizability) like acetonitrile and methanol. Attempts to interpret observed spectral signatures quantitatively relied on the linear-response frameworks of density-functional theory (B3LYP, cam-B3LYP, and dispersion-corrected analogs) and coupled-cluster theory (CCSD), with variants of the polarizable continuum model (PCM) deployed to account for the effects of implicit solvation. Building on the identification of several low-lying equilibrium geometries (nine for R-MBA and three for R-DMBA), ensemble-averaged ORD profiles were calculated at T = 300 K by means of the independent-conformer ansatz, which enabled response properties predicted for the optimized structure of each isomer to be combined through Boltzmann-weighted population fractions derived from corresponding relative internal-energy or free-energy values, the latter of which stemmed from composite CBS-APNO and G4 analyses. Although reasonable accord between theory and experiment was realized for the isolated (vapor-phase) species, the solution-phase results were less satisfactory and tended to degrade progressively as the solvent polarity increased. These trends were attributed to solvent-mediated changes in structural parameters and energy metrics for the transition states that separate and putatively isolate the equilibrium conformations supported by the ground electronic potential-energy surface, with the resulting displacement of barrier locations and/or decrease of barrier heights compromising the underlying premise of the independent-conformer ansatz.
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Affiliation(s)
- Paul M Lemler
- Department of Chemistry, Yale University, New Haven, Connecticut, USA
- Intel Corporation, Hillsboro, Oregon, USA
| | - Clayton L Craft
- Department of Chemistry, Yale University, New Haven, Connecticut, USA
- United States Air Force Research Laboratory, Rome, New York, USA
| | - Corina H Pollok
- Department of Chemistry, Yale University, New Haven, Connecticut, USA
- Organische Chemie II, Ruhr-Universität Bochum, Bochum, Germany
| | - Thomas P Regan
- Department of Chemistry, Yale University, New Haven, Connecticut, USA
| | - Patrick H Vaccaro
- Department of Chemistry, Yale University, New Haven, Connecticut, USA
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9
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Lockhart JPA, Bodipati B, Rizvi S. Investigating the Association Reactions of HOCH 2CO and HOCHCHO with O 2: A Quantum Computational and Master Equation Study. J Phys Chem A 2023; 127:4302-4316. [PMID: 37146175 DOI: 10.1021/acs.jpca.2c08163] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
Glycolaldehyde, HOCH2CHO, is an important multifunctional atmospheric trace gas formed in the oxidation of ethylene and isoprene and emitted directly from burning biomass. The initial step in the atmospheric photooxidation of HOCH2CHO yields HOCH2CO and HOCHCHO radicals; both of these radicals react rapidly with O2 in the troposphere. This study presents a comprehensive theoretical investigation of the HOCH2CO + O2 and HOCHCHO + O2 reactions using high-level quantum chemical calculations and energy-grained master equation simulations. The HOCH2CO + O2 reaction results in the formation of a HOCH2C(O)O2 radical, while the HOCHCHO + O2 reaction yields (HCO)2 + HO2. Density functional theory calculations have identified two open unimolecular pathways associated with the HOCH2C(O)O2 radical that yield HCOCOOH + OH or HCHO + CO2 + OH products; the former novel bimolecular product pathway has not been previously reported in the literature. Master equation simulations based on the potential energy surface calculated here for the HOCH2CO + O2 recombination reaction support experimental product yield data from the literature and indicate that, even at total pressures of 1 atm, the HOCH2CO + O2 reaction yields ∼11% OH at 298 K.
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Affiliation(s)
- J P A Lockhart
- Department of Chemistry, Adelphi University, One South Avenue, Garden City, New York 11530, United States
| | - B Bodipati
- Department of Chemistry, Adelphi University, One South Avenue, Garden City, New York 11530, United States
| | - S Rizvi
- Department of Chemistry, Adelphi University, One South Avenue, Garden City, New York 11530, United States
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10
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Lowe B, Cardona AL, Salas J, Bodi A, Mayer PM, Burgos Paci MA. Probing the pyrolysis of ethyl formate in the dilute gas phase by synchrotron radiation and theory. JOURNAL OF MASS SPECTROMETRY : JMS 2023; 58:e4901. [PMID: 36691327 DOI: 10.1002/jms.4901] [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: 10/31/2022] [Accepted: 01/02/2023] [Indexed: 06/17/2023]
Abstract
The thermal decomposition of the atmospheric constituent ethyl formate was studied by coupling flash pyrolysis with imaging photoelectron photoion coincidence (iPEPICO) spectroscopy using synchrotron vacuum ultraviolet (VUV) radiation at the Swiss Light Source (SLS). iPEPICO allows photoion mass-selected threshold photoelectron spectra (ms-TPES) to be obtained for pyrolysis products. By threshold photoionization and ion imaging, parent ions of neutral pyrolysis products and dissociative photoionization products could be distinguished, and multiple spectral carriers could be identified in several ms-TPES. The TPES and mass-selected TPES for ethyl formate are reported for the first time and appear to correspond to ionization of the lowest energy conformer having a cis (eclipsed) configuration of the O=C(H)-O-C(H2 )-CH3 and trans (staggered) configuration of the O=C(H)-O-C(H2 )-CH3 dihedral angles. We observed the following ethyl formate pyrolysis products: CH3 CH2 OH, CH3 CHO, C2 H6 , C2 H4 , HC(O)OH, CH2 O, CO2 , and CO, with HC(O)OH and C2 H4 pyrolyzing further, forming CO + H2 O and C2 H2 + H2 . The reaction paths and energetics leading to these products, together with the products of two homolytic bond cleavage reactions, CH3 CH2 O + CHO and CH3 CH2 + HC(O)O, were studied computationally at the M06-2X-GD3/aug-cc-pVTZ and SVECV-f12 levels of theory, complemented by further theoretical methods for comparison. The calculated reaction pathways were used to derive Arrhenius parameters for each reaction. The reaction rate constants and branching ratios are discussed in terms of the residence time and newly suggest carbon monoxide as a competitive primary fragmentation product at high temperatures.
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Affiliation(s)
- Bethany Lowe
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, Canada
| | - Alejandro L Cardona
- INFIQC - CONICET, Departamento fisicoquímica, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Juana Salas
- INFIQC - CONICET, Departamento fisicoquímica, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Andras Bodi
- Laboratory for Synchrotron Radiation and Femtochemistry, Paul Scherrer Institute, Villigen, Switzerland
| | - Paul M Mayer
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, Canada
| | - Maxi A Burgos Paci
- INFIQC - CONICET, Departamento fisicoquímica, Universidad Nacional de Córdoba, Córdoba, Argentina
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11
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Zhu S, Xiong Z, Zhou CW. An extensive theoretical study on the thermochemistry of aromatic compounds: from electronic structure to group additivity values. Phys Chem Chem Phys 2022; 24:18582-18599. [PMID: 35894127 DOI: 10.1039/d2cp01459a] [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
An extensive and reliable database of thermodynamic properties of C6-C12 aromatic molecules is constructed by using quantum chemistry calculations. There are 101 molecules in total, which cover a variety of structures including mono-substituted, di-substituted, and bi-cyclic aromatics which can be important intermediates in the combustion of alkylbenzenes. Based on the database, a consistent set of Benson group additive values (GAV) and non-nearest neighbor interactions (NNI) is developed to extend the applicability of Benson's group additivity method for aromatic molecules. Meanwhile, GAVs of existing groups are also updated to improve their accuracy. Geometry optimizations, and vibrational frequency calculations are conducted at the M06-2X/6-311++G(d,p) level of theory. Internal rotor potentials for lower-frequency modes are obtained at the M06-2X/6-31G level of theory. G3 and G4 compound methods are used to derive the 0 K enthalpies of formation via the atomization approach. The entropy and temperature-dependent heat capacity values of all species are calculated via the Master Equation System Solver (MESS) code. This work also provides an extensive literature comparison to validate the calculated results, and good agreement is observed with literature data. The correction terms beyond a group range are explored. The NNIs of di-substituted aromatics with substituents including OH, CHO, and CH3 groups are reported. Entropy reduction is observed in the molecules with two substituents in the ortho position, which mainly derives from the hindered internal rotations. In addition, ring strain corrections (RSC) of dicyclic aromatics are evaluated. The strain energies of molecules with a four-membered side ring are prominently large, as the bond length and bond angle distortions are severely restricted. Ring strain also plays a key role in the C-H bond strength associated with the benzylic carbons in dicyclic aromatics. The loss of a hydrogen atom can destroy the high ring-strain geometry leading to a large C-H bond energy.
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Affiliation(s)
- Shan Zhu
- School of Energy and Power Engineering, Beihang University, Beijing 100191, P. R. China.
| | - Zhuofan Xiong
- School of Energy and Power Engineering, Beihang University, Beijing 100191, P. R. China.
| | - Chong-Wen Zhou
- School of Energy and Power Engineering, Beihang University, Beijing 100191, P. R. China. .,Combustion Chemistry Centre, School of Chemistry, Ryan Institute, National University of Ireland, Galway H91TK33, Ireland
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12
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Otlyotov AA, Minenkov Y, Zaitsau DH, Zherikova KV, Verevkin SP. "In Vitro" and "In Vivo" Diagnostic Check for the Thermochemistry of Metal-Organic Compounds. Inorg Chem 2022; 61:10743-10755. [PMID: 35797430 DOI: 10.1021/acs.inorgchem.2c00959] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Volatile metal β-diketonates are of interest from both practical and theoretical perspectives (manufacturing of film materials, catalysis, and the nature of metal-ligand bonding). Knowledge of their reliable thermochemical properties is essential for effective applications. However, there is an unacceptable scattering of the available data on the enthalpies of formation. In this work, we proposed "in vitro" and "in vivo" diagnostic tools to verify the available enthalpies of formation in both the crystalline and gaseous states for metal tris-β-diketonates. The "in vitro" procedure involved high-level quantum-chemical calculations and was applied to define a consistent data set on the enthalpies of formation for iron(III) β-diketonates. This data set has provided the basis for "in vivo" structure-property-based diagnostics to evaluate the robustness of the thermochemical data for β-diketonate tris-complexes with metals other than iron.
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Affiliation(s)
- Arseniy A Otlyotov
- N. N. Semenov Federal Research Center for Chemical Physics RAS, Moscow 119991, Russian Federation
| | - Yury Minenkov
- N. N. Semenov Federal Research Center for Chemical Physics RAS, Moscow 119991, Russian Federation.,Joint Institute for High Temperatures, Russian Academy of Sciences, Moscow 125412, Russian Federation
| | - Dzmitry H Zaitsau
- Department of Physical Chemistry and Faculty of Interdisciplinary Research, Competence Centre CALOR, University of Rostock, 18059 Rostock, Germany
| | - Kseniya V Zherikova
- Nikolaev Institute of Inorganic Chemistry of Siberian Branch of Russian Academy of Sciences, Novosibirsk 630090, Russian Federation
| | - Sergey P Verevkin
- Department of Physical Chemistry and Faculty of Interdisciplinary Research, Competence Centre CALOR, University of Rostock, 18059 Rostock, Germany.,Department of Physical Chemistry, Kazan Federal University, Kazan 420008, Russian Federation
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13
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Lowe B, Cardona AL, Salas J, Bodi A, Burgos Paci MA, Mayer PM. Probing the pyrolysis of methyl formate in the dilute gas phase by synchrotron radiation and theory. JOURNAL OF MASS SPECTROMETRY : JMS 2022; 57:e4868. [PMID: 35698788 DOI: 10.1002/jms.4868] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2022] [Revised: 04/22/2022] [Accepted: 05/26/2022] [Indexed: 06/15/2023]
Abstract
The thermal dissociation of the atmospheric constituent methyl formate was probed by coupling pyrolysis with imaging photoelectron photoion coincidence spectroscopy (iPEPICO) using synchrotron VUV radiation at the Swiss Light Source (SLS). iPEPICO allows threshold photoelectron spectra to be obtained for pyrolysis products, distinguishing isomers and separating ionic and neutral dissociation pathways. In this work, the pyrolysis products of dilute methyl formate, CH3 OC(O)H, were elucidated to be CH3 OH + CO, 2 CH2 O and CH4 + CO2 as in part distinct from the dissociation of the radical cation (CH3 OH+• + CO and CH2 OH+ + HCO). Density functional theory, CCSD(T), and CBS-QB3 calculations were used to describe the experimentally observed reaction mechanisms, and the thermal decomposition kinetics and the competition between the reaction channels are addressed in a statistical model. One result of the theoretical model is that CH2 O formation was predicted to come directly from methyl formate at temperatures below 1200 K, while above 1800 K, it is formed primarily from the thermal decomposition of methanol.
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Affiliation(s)
- Bethany Lowe
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, Ontario, Canada
| | - Alejandro L Cardona
- INFIQC-CONICET, Departamento Fisicoquímica, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Juana Salas
- INFIQC-CONICET, Departamento Fisicoquímica, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Andras Bodi
- Laboratory for Synchrotron Radiation and Femtochemistry, Paul Scherrer Institute, Villigen, Switzerland
| | - Maxi A Burgos Paci
- INFIQC-CONICET, Departamento Fisicoquímica, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Paul M Mayer
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, Ontario, Canada
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14
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Giri BR, Farooq A, Szőri M, Roscoe JM. The kinetics of the reactions of Br atoms with the xylenes: an experimental and theoretical study. Phys Chem Chem Phys 2022; 24:4843-4858. [PMID: 35080539 DOI: 10.1039/d1cp03740d] [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
This work reports the temperature dependence of the rate coefficients for the reactions of atomic bromine with the xylenes that are determined experimentally and theoretically. The experiments were carried out in a Pyrex chamber equipped with fluorescent lamps to measure the rate coefficients at temperatures from 295 K to 346 K. Experiments were made at several concentrations of oxygen to assess its potential kinetic role under atmospheric conditions and to validate comparison of our rate coefficients with those obtained by others using air as the diluent. Br2 was used to generate Br atoms photolytically. The relative rate method was used to obtain the rate coefficients for the reactions of Br atoms with the xylenes. The reactions of Br with both toluene and diethyl ether (DEE) were used as reference reactions where the loss of the organic reactants was measured by gas chromatography. The rate coefficient for the reaction of Br with diethyl ether was also measured in the same way over the same temperature range with toluene as the reference reactant. The rate coefficients were independent of the concentration of O2. The experimentally determined temperature dependence of the rate coefficients of these reactions can be given in the units cm3 molecule-1 s-1 by: o-xylene + Br, log10(k) = (-10.03 ± 0.35) - (921 ± 110)/T; m-xylene + Br, log10(k) = (-10.78 ± 0.09) - (787 ± 92/T); p-xylene + Br, log10(k) = (-9.98 ± 0.39) - (956 ± 121)/T; diethyl ether + Br, log10(k) = (-7.69 ± 0.55) - (1700 ± 180)/T). This leads to the following rate coefficients, in the units of cm3 molecule-1 s-1, based on our experimental measurements: o-xylene + Br, k(298 K) = 7.53 × 10-14; m-xylene + Br, k(298 K) = 3.77 × 10-14; p-xylene + Br, k(298 K) = 6.43 × 10-14; diethyl ether + Br, k(298 K) = 4.02 × 10-14. Various ab initio methods including G3, G4, CCSD(T)/cc-pV(D,T)Z//MP2/aug-cc-pVDZ and CCSD(T)/cc-pV(D,T)Z//B3LYP/cc-pVTZ levels of theory were employed to gain detailed information about the kinetics as well as the thermochemical quantities. Among the ab initio methods, the G4 method performed remarkably well in describing the kinetics and thermochemistry of the xylenes + Br reaction system. Our theoretical calculations revealed that the reaction of Br atoms with the xylenes proceeds via a complex forming mechanism in an overall endothermic reaction. The rate determining step is the intramolecular rearrangement of the pre-reactive complex leading to the post-reactive complex. After lowering the relative energy of the corresponding transition state by less than 1.5 kJ mol-1 for this step in the reaction of each of the xylenes with Br, the calculated rate coefficients are in very good agreement with the experimental data.
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Affiliation(s)
- Binod R Giri
- King Abdullah University of Science and Technology (KAUST), Clean Combustion Research Center, Division of Physical Sciences and Engineering, Thuwal 23955-6900, Saudi Arabia.
| | - Aamir Farooq
- King Abdullah University of Science and Technology (KAUST), Clean Combustion Research Center, Division of Physical Sciences and Engineering, Thuwal 23955-6900, Saudi Arabia.
| | - Milán Szőri
- Institute of Chemistry, Faculty of Materials Science and Engineering, University of Miskolc, Egyetemváros A/4, H-3515 Miskolc, Hungary
| | - John M Roscoe
- Department of Chemistry, Acadia University, Wolfville, Nova Scotia, B4P 2R6, Canada.
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15
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Quantum-chemical calculations of physicochemical properties of high enthalpy 1,2,3,4- and 1,2,4,5-tetrazines annelated with polynitroderivatives of pyrrole and pyrazole. Comparison of different calculation methods. COMPUT THEOR CHEM 2022. [DOI: 10.1016/j.comptc.2022.113608] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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16
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Wang H, Guan J, Gao J, Li Y, Zhang J, Shan X, Wang Z. Discriminating between the dissociative photoionization and thermal decomposition products of ethylene glycol by synchrotron VUV photoionization mass spectrometry and theoretical calculations. Phys Chem Chem Phys 2022; 24:26915-26925. [DOI: 10.1039/d2cp03769f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Landscape of dissociative photoionization and thermal decompositions of ethylene glycol.
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Affiliation(s)
- Hong Wang
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, Anhui 230029, P. R. China
| | - Jiwen Guan
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, Anhui 230029, P. R. China
| | - Jiao Gao
- Dalian Institute of Chemical Physics, Dalian, 116023, P. R. China
| | - Yanbo Li
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, Anhui 230029, P. R. China
| | - Jinyang Zhang
- State Key Laboratory of Fire Science, University of Science and Technology of China, Hefei, Anhui 230026, P. R. China
| | - Xiaobin Shan
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, Anhui 230029, P. R. China
| | - Zhandong Wang
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, Anhui 230029, P. R. China
- State Key Laboratory of Fire Science, University of Science and Technology of China, Hefei, Anhui 230026, P. R. China
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17
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Farina DS, Sirumalla SK, Mazeau EJ, West RH. Extensive High-Accuracy Thermochemistry and Group Additivity Values for Halocarbon Combustion Modeling. Ind Eng Chem Res 2021. [DOI: 10.1021/acs.iecr.1c03076] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- David S. Farina
- Department of Chemical Engineering, Northeastern University, Boston, Massachusetts 02115, United States
| | - Sai Krishna Sirumalla
- Department of Chemical Engineering, Northeastern University, Boston, Massachusetts 02115, United States
| | - Emily J. Mazeau
- Department of Chemical Engineering, Northeastern University, Boston, Massachusetts 02115, United States
| | - Richard H. West
- Department of Chemical Engineering, Northeastern University, Boston, Massachusetts 02115, United States
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18
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Accidental Combustion Phenomena at Cryogenic Conditions. SAFETY 2021. [DOI: 10.3390/safety7040067] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
The presented state of the art can be intended as an overview of the current understandings and the remaining challenges on the phenomenological aspects involving systems operating at ultra-low temperature, which typically characterize the cryogenic fuels, i.e., liquefied natural gas and liquefied hydrogen. To this aim, thermodynamic, kinetic, and technological aspects were included and integrated. Either experimental or numerical techniques currently available for the evaluation of safety parameters and the overall reactivity of systems at cryogenic temperatures were discussed. The main advantages and disadvantages of different alternatives were compared. Theoretical background and suitable models were reported given possible implementation to the analyzed conditions. Attention was paid to models describing peculiar phenomena mainly relevant at cryogenic temperatures (e.g., para-to-ortho transformation and thermal stratification in case of accidental release) as well as critical aspects involving standard phenomena (e.g., ultra-low temperature combustion and evaporation rate).
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19
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Unknown Knowns: Case studies in uncertainties in the computation of thermochemical parameters. Chem Phys 2021. [DOI: 10.1016/j.chemphys.2021.111251] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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20
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Abstract
Bond dissociation energy (BDE) has been calculated for a series of compounds that contain N-O bonds. These structures encompass model N,N,O-trisubstituted hydroxylamines that include O-methoxy, O-acyl, and O-phenyl hydroxylamines. The calculations used three accurate composite methods, CBS-QB3, CBS-APNO, and G4 methods and the computationally more affordable M06-2X/6-311+G(3df,2p) density functional theory (DFT) functional. The calculated N-O single-bond BDEs are 5-15 kcal/mol higher than a generic N-O BDE of 48 kcal/mol quoted in the literature and in textbooks. The M06-2X DFT functional provides BDEs that are in excellent agreement with the higher-level composite methods. We also provided a comparison of the N-O BDE for pyridine-N-oxide to simple trialkylamine oxides. Based on an experimental BDE of 63.3 ± 0.5 kcal/mol for pyridine-N-oxide, our best estimate gives 56.7 ± 0.9 kcal/mol N-O BDE for trimethylamine-N-oxide and 59.0 ± 0.8 kcal/mol for triethylamine-N-oxide.
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Affiliation(s)
- Robert D Bach
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, United States
| | - H Bernhard Schlegel
- Department of Chemistry, Wayne State University, Detroit, Michigan 48202-3489, United States
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21
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Power J, Somers KP, Nagaraja SS, Curran HJ. Hierarchical Study of the Reactions of Hydrogen Atoms with Alkenes: A Theoretical Study of the Reactions of Hydrogen Atoms with C 2-C 4 Alkenes. J Phys Chem A 2021; 125:5124-5145. [PMID: 34100614 PMCID: PMC8279655 DOI: 10.1021/acs.jpca.1c03168] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
![]()
The present study
complements our previous studies of the reactions
of hydrogen atoms with C5 alkene species including 1- and
2-pentene and the branched isomers (2-methyl-1-butene, 2-methyl-2-butene,
and 3-methyl-1-butene), by studying the reactions of hydrogen atoms
with C2–C4 alkenes (ethylene, propene,
1- and 2-butene, and isobutene). The aim of the current work is to
develop a hierarchical set of rate constants for Ḣ atom addition
reactions to C2–C5 alkenes, both linear
and branched, which can be used in the development of chemical kinetic
models. High-pressure limiting and pressure-dependent rate constants
are calculated using the Rice–Ramsperger–Kassel–Marcus
(RRKM) theory and a one-dimensional master equation (ME). Rate constant
recommendations for Ḣ atom addition and abstraction reactions
in addition to alkyl radical decomposition reactions are also proposed
and provide a useful tool for use in mechanisms of larger alkenes
for which calculations do not exist. Additionally, validation of our
theoretical results with single-pulse shock-tube pyrolysis experiments
is carried out. An improvement in species mole fraction predictions
for alkene pyrolysis is observed, showing the relevance of the present
study.
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Affiliation(s)
- Jennifer Power
- Combustion Chemistry Centre, School of Chemistry, Ryan Institute, MaREI, National University of Ireland, Galway, Galway H91TK33, Ireland
| | - Kieran P Somers
- Combustion Chemistry Centre, School of Chemistry, Ryan Institute, MaREI, National University of Ireland, Galway, Galway H91TK33, Ireland
| | - Shashank S Nagaraja
- Combustion Chemistry Centre, School of Chemistry, Ryan Institute, MaREI, National University of Ireland, Galway, Galway H91TK33, Ireland
| | - Henry J Curran
- Combustion Chemistry Centre, School of Chemistry, Ryan Institute, MaREI, National University of Ireland, Galway, Galway H91TK33, Ireland
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22
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Chattopadhyay A, Gierczak T, Marshall P, Papadimitriou VC, Burkholder JB. Kinetic fall-off behavior for the Cl + Furan-2,5-dione (C 4H 2O 3, maleic anhydride) reaction. Phys Chem Chem Phys 2021; 23:4901-4911. [PMID: 33616582 DOI: 10.1039/d0cp06402e] [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
Rate coefficients, k, for the gas-phase Cl + Furan-2,5-dione (C4H2O3, maleic anhydride) reaction were measured over the 15-500 torr (He and N2 bath gas) pressure range at temperatures between 283 and 323 K. Kinetic measurements were performed using pulsed laser photolysis (PLP) to produce Cl atoms and atomic resonance fluorescence (RF) to monitor the Cl atom temporal profile. Complementary relative rate (RR) measurements were performed at 296 K and 620 torr pressure (syn. air) and found to be in good agreement with the absolute measurements. A Troe-type fall-off fit of the temperature and pressure dependence yielded the following rate coefficient parameters: ko(T) = (9.4 ± 0.5) × 10-29 (T/298)-6.3 cm6 molecule-2 s-1, k∞(T) = (3.4 ± 0.5) × 10-11 (T/298)-1.4 cm3 molecule-1 s-1. The formation of a Cl·C4H2O3 adduct intermediate was deduced from the Cl atom temporal profiles and an equilibrium constant, KP(T), for the Cl + C4H2O3 ↔ Cl·C4H2O3 reaction was determined. A third-law analysis yielded ΔH = -15.7 ± 0.4 kcal mol-1 with ΔS = -25.1 cal K-1 mol-1, where ΔS was derived from theoretical calculations at the B3LYP/6-311G(2d,p,d) level. In addition, the rate coefficient for the Cl·C4H2O3 + O2 reaction at 296 K was measured to be (2.83 ± 0.16) × 10-12 cm3 molecule-1 s-1, where the quoted uncertainty is the 2σ fit precision. Stable end-product molar yields of (83 ± 7), (188 ± 10), and (65 ± 10)% were measured for CO, CO2, and HC(O)Cl, respectively, in an air bath gas. An atmospheric degradation mechanism for C4H2O3 is proposed based on the observed product yields and theoretical calculations of ring-opening pathways and activation barrier energies at the CBS-QB3 level of theory.
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Affiliation(s)
- Aparajeo Chattopadhyay
- Chemical Sciences Laboratory, National Oceanic and Atmospheric Administration, 325 Broadway, Boulder, CO 80305-3327, USA. and Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO 80309, USA
| | - Tomasz Gierczak
- Chemical Sciences Laboratory, National Oceanic and Atmospheric Administration, 325 Broadway, Boulder, CO 80305-3327, USA. and Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO 80309, USA
| | - Paul Marshall
- Chemical Sciences Laboratory, National Oceanic and Atmospheric Administration, 325 Broadway, Boulder, CO 80305-3327, USA. and Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO 80309, USA and Department of Chemistry and Center for Advanced Scientific Computing and Modeling, University of North Texas, 1155 Union Circle #305070, Denton, Texas 76203, USA
| | - Vassileios C Papadimitriou
- Chemical Sciences Laboratory, National Oceanic and Atmospheric Administration, 325 Broadway, Boulder, CO 80305-3327, USA. and Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO 80309, USA
| | - James B Burkholder
- Chemical Sciences Laboratory, National Oceanic and Atmospheric Administration, 325 Broadway, Boulder, CO 80305-3327, USA.
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23
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Grabovskii SA, Grabovskaya YS, Antipin AV, Kabal’nova NN. Inhibiting Effect of 4-Hydroxy-2,5-Dimethylfuran-3-one on the Radical Chain Oxidation of Styrene. KINETICS AND CATALYSIS 2021. [DOI: 10.1134/s002315842101002x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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24
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Power J, Somers KP, Nagaraja SS, Wyrebak W, Curran HJ. Theoretical Study of the Reaction of Hydrogen Atoms with Three Pentene Isomers: 2-Methyl-1-butene, 2-Methyl-2-butene, and 3-Methyl-1-butene. J Phys Chem A 2020; 124:10649-10666. [PMID: 33320690 DOI: 10.1021/acs.jpca.0c06389] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
This paper presents a comprehensive potential energy surface (PES) for hydrogen atom addition to and abstraction from 2-methyl-1-butene, 2-methyl-2-butene, and 3-methyl-1-butene and the subsequent ß-scission and H atom transfer reactions. Thermochemical parameters for species on the Ċ5H11 potential energy surface (PES) were calculated as a function of temperature (298-2000 K), using a series of isodesmic reactions to determine the formation enthalpies. High-pressure limiting and pressure-dependent rate constants were calculated using Rice-Ramsperger-Kassel-Marcus theory with a one-dimensional master equation. A number of studies have highlighted the fact that C5 intermediate species play a role in polyaromatic hydrocarbon formation and that a fuel's chemical structure can be key in understanding the intermediate species formed during fuel decomposition. Rate constant recommendations for both Ḣ atom addition to, and H-atom abstraction by Ḣ atoms from, linear and branched alkenes have subsequently been proposed by incorporating our earlier work on 1- and 2-pentene, and these can be used in mechanisms of larger alkenes for which calculations do not exist. The current set of rate constants for the reactions of Ḣ atoms with both linear and branched C5 alkenes, including their chemically activated pathways, are the first available in the literature of any reasonable fidelity for combustion modeling and are important for gasoline mechanisms. Validation of our theoretical results with pyrolysis experiments of 2-methyl-1-butene, 2-methyl-2-butene, and 3-methyl-1-butene at 2 bar in a single pulse shock tube (SPST) were carried out, with satisfactory agreement observed.
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Affiliation(s)
- Jennifer Power
- Combustion Chemistry Centre, School of Chemistry & Ryan Institute, National University of Ireland Galway H91TK33, Ireland
| | - Kieran P Somers
- Combustion Chemistry Centre, School of Chemistry & Ryan Institute, National University of Ireland Galway H91TK33, Ireland
| | - Shashank S Nagaraja
- Combustion Chemistry Centre, School of Chemistry & Ryan Institute, National University of Ireland Galway H91TK33, Ireland
| | - Weronika Wyrebak
- Combustion Chemistry Centre, School of Chemistry & Ryan Institute, National University of Ireland Galway H91TK33, Ireland
| | - Henry J Curran
- Combustion Chemistry Centre, School of Chemistry & Ryan Institute, National University of Ireland Galway H91TK33, Ireland
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25
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Würmel J, Somers KP, Simmie JM. Ethyl lactate: a sinister molecule exhibiting high chemical diversity with potential as a “green” solvent. INT J CHEM KINET 2020. [DOI: 10.1002/kin.21456] [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)
| | - Kieran P. Somers
- School of Chemistry National University of Ireland Galway Ireland
| | - John M. Simmie
- School of Chemistry National University of Ireland Galway Ireland
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26
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Giri BR, Roscoe JM, Szőri M, Farooq A. A theoretical kinetic study on the reaction of atomic bromine with toluene. INT J CHEM KINET 2020. [DOI: 10.1002/kin.21451] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Binod Raj Giri
- Clean Combustion Research Center Division of Physical Sciences and Engineering King Abdullah University of Science and Technology (KAUST) Thuwal Saudi Arabia
| | - John M. Roscoe
- Department of Chemistry Acadia University Wolfville Nova Scotia Canada
| | - Milán Szőri
- Institute of Chemistry, Faculty of Materials Science and Engineering University of Miskolc Miskolc Hungary
| | - Aamir Farooq
- Clean Combustion Research Center Division of Physical Sciences and Engineering King Abdullah University of Science and Technology (KAUST) Thuwal Saudi Arabia
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27
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Pappijn CA, Vermeire FH, Van de Vijver R, Reyniers M, Marin GB, Van Geem KM. Bond additivity corrections for CBS‐QB3 calculated standard enthalpies of formation of H, C, O, N, and S containing species. INT J CHEM KINET 2020. [DOI: 10.1002/kin.21447] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Affiliation(s)
- Cato A.R. Pappijn
- Laboratory for Chemical Technology Ghent University Zwijnaarde Belgium
| | | | | | | | - Guy B. Marin
- Laboratory for Chemical Technology Ghent University Zwijnaarde Belgium
| | - Kevin M. Van Geem
- Laboratory for Chemical Technology Ghent University Zwijnaarde Belgium
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29
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Abstract
An innovative and informed methodology for the rational design and testing of anti-knock additives is reported. Interaction of the additives with OH● and HO2● is identified as the key reaction pathway by which non-metallic anti-knock additives are proposed to operate. Based on this mechanism, a set of generic design criteria for anti-knock additives is outlined. It is suggested that these additives should contain a weak X-H bond and form stable radical species after hydrogen atom abstraction. A set of molecular structural, thermodynamic, and kinetic quantities that pertain to the propensity of the additive to inhibit knock by this mechanism are identified and determined for a set of 12 phenolic model compounds. The series of structural analogues was carefully selected such that the physical thermodynamic and kinetic quantities could be systematically varied. The efficacy of these molecules as anti-knock additives was demonstrated through the determination of the research octane number (RON) and the derived cetane number(DCN), measured using an ignition quality tester (IQT), of a RON 95 gasoline treated with 1 mole % of the additive. The use of the IQT allows the anti-knock properties of potential additives to be studied on one tenth of the scale, compared to the analogous RON measurement. Using multiple linear regression, the relationship between DCN/RON and the theoretically determined quantities is studied. The overall methodology reported is proposed as an informed alternative to the non-directed experimental screening approach typically adopted in the development of fuel additives.
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30
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Lee J, Caster K, Maddaleno T, Donnellan Z, Selby TM, Goulay F. Kinetic study of the CN radical reaction with 2‐methylfuran. INT J CHEM KINET 2020. [DOI: 10.1002/kin.21403] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- James Lee
- C. Eugene Bennett Department of Chemistry West Virginia University Morgantown West Virginia
| | - Kacee Caster
- C. Eugene Bennett Department of Chemistry West Virginia University Morgantown West Virginia
| | - Trey Maddaleno
- C. Eugene Bennett Department of Chemistry West Virginia University Morgantown West Virginia
| | - Zachery Donnellan
- C. Eugene Bennett Department of Chemistry West Virginia University Morgantown West Virginia
| | - Talitha M. Selby
- Department of Mathematics and Natural Sciences University of Wisconsin‐Milwaukee West Bend Wisconsin
| | - Fabien Goulay
- C. Eugene Bennett Department of Chemistry West Virginia University Morgantown West Virginia
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31
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Li Y, Zhao Q, Zhang Y, Huang Z, Sarathy SM. A Systematic Theoretical Kinetics Analysis for the Waddington Mechanism in the Low-Temperature Oxidation of Butene and Butanol Isomers. J Phys Chem A 2020; 124:5646-5656. [PMID: 32574048 PMCID: PMC7467721 DOI: 10.1021/acs.jpca.0c03515] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
![]()
The
Waddington mechanism, or the Waddington-type reaction pathway,
is crucial for low-temperature oxidation of both alkenes and alcohols.
In this study, the Waddington mechanism in the oxidation chemistry
of butene and butanol isomers was systematically investigated. Fundamental
quantum chemical calculations were conducted for the rate constants
and thermodynamic properties of the reactions and species in this
mechanism. Calculations were performed using two different ab initio solvers: Gaussian 09 and Orca 4.0.0, and two different
kinetic solvers: PAPR and MultiWell, comprehensively. Temperature-
and pressure-dependent rate constants were performed based on the
transition state theory, associated with the Rice Ramsperger Kassel
Marcus and master equation theories. Temperature-dependent thermochemistry
(enthalpies of formation, entropy, and heat capacity) of all major
species was also conducted, based on the statistical thermodynamics.
Of the two types of reaction, dissociation reactions were significantly
faster than isomerization reactions, while the rate constants of both
reactions converged toward higher temperatures. In comparison, between
two ab initio solvers, the barrier height difference
among all isomerization and dissociation reactions was about 2 and
0.5 kcal/mol, respectively, resulting in less than 50%, and a factor
of 2–10 differences for the predicted rate coefficients of
the two reaction types, respectively. Comparing the two kinetic solvers,
the rate constants of the isomerization reactions showed less than
a 32% difference, while the rate of one dissociation reaction (P1
↔ WDT12) exhibited 1–2 orders of magnitude discrepancy.
Compared with results from the literature, both reaction rate coefficients
(R4 and R5 reaction systems) and species’ thermochemistry (all
closed shell molecules and open shell radicals R4 and R5) showed good
agreement with the corresponding values obtained from the literature.
All calculated results can be directly used for the chemical kinetic
model development of butene and butanol isomer oxidation.
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Affiliation(s)
- Yang Li
- King Abdullah University of Science and Technology, Clean Combustion Research Centre, Thuwal 23955, Saudi Arabia
| | - Qian Zhao
- State Key Laboratory of Multiphase Flows in Power Engineering, Xi'an Jiaotong University, Xi'an 710049, People's Republic of China
| | - Yingjia Zhang
- State Key Laboratory of Multiphase Flows in Power Engineering, Xi'an Jiaotong University, Xi'an 710049, People's Republic of China
| | - Zuohua Huang
- State Key Laboratory of Multiphase Flows in Power Engineering, Xi'an Jiaotong University, Xi'an 710049, People's Republic of China
| | - S Mani Sarathy
- King Abdullah University of Science and Technology, Clean Combustion Research Centre, Thuwal 23955, Saudi Arabia
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32
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Kwon H, Etz BD, Montgomery MJ, Messerly R, Shabnam S, Vyas S, van Duin ACT, McEnally CS, Pfefferle LD, Kim S, Xuan Y. Reactive Molecular Dynamics Simulations and Quantum Chemistry Calculations To Investigate Soot-Relevant Reaction Pathways for Hexylamine Isomers. J Phys Chem A 2020; 124:4290-4304. [PMID: 32364731 DOI: 10.1021/acs.jpca.0c03355] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Sooting tendencies of a series of nitrogen-containing hydrocarbons (NHCs) have been recently characterized experimentally using the yield sooting index (YSI) methodology. This work aims to identify soot-relevant reaction pathways for three selected C6H15N amines, namely, dipropylamine (DPA), diisopropylamine (DIPA), and 3,3-dimethylbutylamine (DMBA) using ReaxFF molecular dynamics (MD) simulations and quantum mechanical (QM) calculations and to interpret the experimentally observed trends. ReaxFF MD simulations are performed to determine the important intermediate species and radicals involved in the fuel decomposition and soot formation processes. QM calculations are employed to extensively search for chemical reactions involving these species and radicals based on the ReaxFF MD results and also to quantitatively characterize the potential energy surfaces. Specifically, ReaxFF simulations are carried out in the NVT ensemble at 1400, 1600, and 1800 K, where soot has been identified to form in the YSI experiment. These simulations account for the interactions among test fuel molecules and pre-existing radicals and intermediate species generated from rich methane combustion, using a recently proposed simulation framework. ReaxFF simulations predict that the reactivity of the amines decrease in the order DIPA > DPA > DMBA, independent of temperature. Both QM calculations and ReaxFF simulations predict that C2H4, C3H6, and C4H8 are the main nonaromatic soot precursors formed during the decomposition of DPA, DIPA, and DMBA, respectively, and the associated reaction pathways are identified for each amine. Both theoretical methods predict that sooting tendency increases in the order DPA, DIPA, and DMBA, consistent with the experimentally measured trend in YSI. This work demonstrates that sooting tendencies and soot-relevant reaction pathways of fuels with unknown chemical kinetics can be identified efficiently through combined ReaxFF and QM simulations. Overall, predictions from ReaxFF simulations and QM calculations are consistent, in terms of fuel reactivity, major intermediates, and major nonaromatic soot precursors.
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Affiliation(s)
- Hyunguk Kwon
- Department of Chemical Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Brian D Etz
- National Renewable Energy Laboratory, Golden, Colorado 80401, United States.,Department of Chemistry, Colorado School of Mines, Golden, Colorado 80401, United States
| | - Matthew J Montgomery
- Department of Chemical and Environmental Engineering, Yale University, New Haven, Connecticut 06520, United States
| | - Richard Messerly
- National Renewable Energy Laboratory, Golden, Colorado 80401, United States
| | - Sharmin Shabnam
- Department of Mechanical Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Shubham Vyas
- Department of Chemistry, Colorado School of Mines, Golden, Colorado 80401, United States
| | - Adri C T van Duin
- Department of Mechanical Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Charles S McEnally
- Department of Chemical and Environmental Engineering, Yale University, New Haven, Connecticut 06520, United States
| | - Lisa D Pfefferle
- Department of Chemical and Environmental Engineering, Yale University, New Haven, Connecticut 06520, United States
| | - Seonah Kim
- National Renewable Energy Laboratory, Golden, Colorado 80401, United States
| | - Yuan Xuan
- Department of Mechanical Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
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33
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Hudzik JM, Barekati-Goudarzi M, Khachatryan L, Bozzelli JW, Ruckenstein E, Asatryan R. OH-Initiated Reactions of para-Coumaryl Alcohol Relevant to the Lignin Pyrolysis. Part II. Kinetic Analysis. J Phys Chem A 2020; 124:4875-4904. [DOI: 10.1021/acs.jpca.9b11894] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Jason M. Hudzik
- Department of Chemistry and Environmental Science, New Jersey Institute of Technology, Newark, New Jersey 07102, United States
| | | | - Lavrent Khachatryan
- Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803, United States
| | - Joseph W. Bozzelli
- Department of Chemistry and Environmental Science, New Jersey Institute of Technology, Newark, New Jersey 07102, United States
| | - Eli Ruckenstein
- Department of Chemical and Biological Engineering, University at Buffalo, The State University of New York, Buffalo, New York 14226, United States
| | - Rubik Asatryan
- Department of Chemical and Biological Engineering, University at Buffalo, The State University of New York, Buffalo, New York 14226, United States
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34
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Liu P, Li Y, Sarathy SM, Roberts WL. Gas-to-Liquid Phase Transition of PAH at Flame Temperatures. J Phys Chem A 2020; 124:3896-3903. [PMID: 32345025 DOI: 10.1021/acs.jpca.0c01912] [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
Significant evidence has shown that soot can be formed from polycyclic aromatic hydrocarbon (PAH) in combustion environments, but the transition of high molecular PAH from the gas phase to soot in a liquid or solid state remains unclear. In this study, the relationships between the boiling points of various planar PAHs and their thermodynamic properties are systematically investigated, to find a satisfactory marker for the phase transition event. Temperature-dependent thermodynamic properties, including entropy, specific heat capacity, enthalpy, and Gibbs free energy, are simultaneously calculated for PAHs, using density functional theory and three composite compound methods. Comparison of the results indicates that the individual G3 method, plus an atomization reaction approach, produces the most accurate thermochemistry parameters. Compared to entropy, enthalpy, and Gibbs free energy, the specific heat capacity at 298 K is found to be a better marker for the boiling point of PAHs due to the observed linear correlation, predictable characteristics, and fidelity of accuracy as a function of temperature. The correlation equation Y = 10.996X + 122.111 is proposed (where Y is the boiling temperature (K) and X is Cp at 298 K (cal/K/mol)). The standard deviation is as low as 16.7 K when comparing the calculated boiling points and experimentally determined values for 25 different aromatic species ranging from benzene to ovalene (C32H14). The effects of carbon number, structural arrangement, and partial pressure on the boiling point of large planar PAH are discussed. The results reveal that the carbon number in large planar PAH is the dominant factor determining its boiling points. It is shown that PAHs containing about 60-65 carbon atoms are likely to exist as liquids in flames, although the partial pressure of such species is very low.
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Affiliation(s)
- Peng Liu
- King Abdullah University of Science and Technology (KAUST), Clean Combustion Research Center, Physical Sciences and Engineering Division, Thuwal 23955-6900, Saudi Arabia
| | - Yang Li
- King Abdullah University of Science and Technology (KAUST), Clean Combustion Research Center, Physical Sciences and Engineering Division, Thuwal 23955-6900, Saudi Arabia
| | - S Mani Sarathy
- King Abdullah University of Science and Technology (KAUST), Clean Combustion Research Center, Physical Sciences and Engineering Division, Thuwal 23955-6900, Saudi Arabia
| | - William L Roberts
- King Abdullah University of Science and Technology (KAUST), Clean Combustion Research Center, Physical Sciences and Engineering Division, Thuwal 23955-6900, Saudi Arabia
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35
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Affiliation(s)
- Robert D. Bach
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, United States
| | - H. Bernhard Schlegel
- Department of Chemistry, Wayne State University, Detroit, Michigan 48202-3489, United States
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36
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Grabovskii SA, Andriyashina NM, Grabovskaya YS, Antipin AV, Kabal'nova NN. Reactivity of 5‐aminouracil derivatives towards peroxyl radicals. J PHYS ORG CHEM 2020. [DOI: 10.1002/poc.4065] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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37
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Gao Y, You X. On the Prediction of Standard Enthalpy of Formation of C2-C4 Oxygenated Species. J Phys Chem A 2019; 123:11004-11011. [PMID: 31800247 DOI: 10.1021/acs.jpca.9b08516] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
In this study, to determine an efficient and accurate method for predicting standard enthalpy of formation (ΔfHo) of oxygenated species, we calculated ΔfHo for several typical C2-C4 oxygenated species using atomization and isodesmic reactions in combination with various quantum chemical methods, including six density functional theory methods, three compound methods, and CCSD(T)/CBS. Compared with experimental values, at the same quantum chemical level, ΔfHo values predicted by using isodesmic reactions are more accurate than those using atomization reactions. Comparing various quantum chemical methods when isodesmic reactions are used, the performance of G4 is the best with a mean unsigned deviation (MUE) of 0.3 kcal/mol and a standard deviation (SD) of 0.3 kcal/mol, while M06-2X can predict ΔfHo efficiently and accurately with an MUE of 0.6 kcal/mol and SD of 0.5 kcal/mol. Using the best methods we have found, we calculated the enthalpies of formation and other thermodynamic properties for dimethyl carbonate (DMC) and its associated species and then applied them in a DMC combustion model for predicting ignition delay times. Better agreement with the experiments is achieved when the newly computed thermodynamic properties are adopted.
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38
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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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39
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Gupta D, Cheikh Sid Ely S, Cooke IR, Guillaume T, Abdelkader Khedaoui O, Hearne TS, Hays BM, Sims IR. Low Temperature Kinetics of the Reaction Between Methanol and the CN Radical. J Phys Chem A 2019; 123:9995-10003. [DOI: 10.1021/acs.jpca.9b08472] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Divita Gupta
- Univ Rennes, CNRS, IPR (Institut de Physique de Rennes) - UMR 6251, F-35000 Rennes, France
| | - Sidaty Cheikh Sid Ely
- Univ Rennes, CNRS, IPR (Institut de Physique de Rennes) - UMR 6251, F-35000 Rennes, France
| | - Ilsa R. Cooke
- Univ Rennes, CNRS, IPR (Institut de Physique de Rennes) - UMR 6251, F-35000 Rennes, France
| | - Théo Guillaume
- Univ Rennes, CNRS, IPR (Institut de Physique de Rennes) - UMR 6251, F-35000 Rennes, France
| | | | - Thomas S. Hearne
- Univ Rennes, CNRS, IPR (Institut de Physique de Rennes) - UMR 6251, F-35000 Rennes, France
| | - Brian M. Hays
- Univ Rennes, CNRS, IPR (Institut de Physique de Rennes) - UMR 6251, F-35000 Rennes, France
| | - Ian R. Sims
- Univ Rennes, CNRS, IPR (Institut de Physique de Rennes) - UMR 6251, F-35000 Rennes, France
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40
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Power J, Somers KP, Zhou CW, Peukert S, Curran HJ. Theoretical, Experimental, and Modeling Study of the Reaction of Hydrogen Atoms with 1- and 2-Pentene. J Phys Chem A 2019; 123:8506-8526. [PMID: 31502844 DOI: 10.1021/acs.jpca.9b06378] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Alkyl radicals are prominent in combustion chemistry as they are formed by hydrocarbon decomposition or from a radical attack on hydrocarbons. Accurate determinations of the thermochemistry and kinetics of their unimolecular isomerization and decomposition reactions and related addition reactions of alkenes are therefore important in simulating the combustion chemistry of virtually all hydrocarbon fuels. In this work, a comprehensive potential energy surface (PES) for Ḣ-atom addition to and abstraction from 1- and 2-pentene, and the subsequent C-C and C-H β-scission reactions, and H-atom transfer reactions has been considered. Thermochemical values for the species on the Ċ5H11 PES were calculated as a function of temperature (298-2000 K), with enthalpies of formation determined using a network of isodesmic reactions. High-pressure limiting and pressure-dependent rate constants were calculated using the Rice-Ramsperger-Kassel-Marcus theory coupled with a one-dimensional master equation. As a validation of our theoretical results, hydrogen atomic resonance absorption spectrometry experiments were performed on the Ḣ-atom addition and abstraction reactions of 1- and 2-pentene. By incorporating our calculations into a detailed chemical kinetic model (AramcoMech 3.0), excellent agreement with these experiments is observed. The theoretical results are further validated via a comprehensive series of simulations of literature data. Our a priori model is found to reproduce important absolute species concentrations and product ratios reported therein.
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Affiliation(s)
- Jennifer Power
- Combustion Chemistry Centre, School of Chemistry & Ryan Institute , National University of Ireland , Galway H91TK33 , Ireland
| | - Kieran P Somers
- Combustion Chemistry Centre, School of Chemistry & Ryan Institute , National University of Ireland , Galway H91TK33 , Ireland
| | - Chong-Wen Zhou
- Combustion Chemistry Centre, School of Chemistry & Ryan Institute , National University of Ireland , Galway H91TK33 , Ireland.,School of Energy and Power Engineering , Beihang University , Beijing 100191 , P. R. China
| | - Sebastian Peukert
- Institute for Combustion and Gas Dynamics-Reactive Fluids , University of Duisburg-Essen , 47058 Duisburg , Germany
| | - Henry J Curran
- Combustion Chemistry Centre, School of Chemistry & Ryan Institute , National University of Ireland , Galway H91TK33 , Ireland
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41
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Ventura ON, Kieninger M, Salta Z, Kosmas AM, Barone V. Enthalpies of formation of the benzyloxyl, benzylperoxyl, hydroxyphenyl radicals and related species on the potential energy surface for the reaction of toluene with the hydroxyl radical. Theor Chem Acc 2019. [DOI: 10.1007/s00214-019-2500-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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42
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DFT study of antioxidant molecules from traditional Japanese and Chinese teas: comparing allylic and phenolic antiradical activity. Struct Chem 2019. [DOI: 10.1007/s11224-019-01411-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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43
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Caster KL, Donnellan ZN, Selby TM, Goulay F. Kinetic Investigations of the CH (X2Π) Radical Reaction with Cyclopentadiene. J Phys Chem A 2019; 123:5692-5703. [PMID: 31194547 DOI: 10.1021/acs.jpca.9b03813] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Kacee L. Caster
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, West Virginia 26506, United States
| | - Zachery N. Donnellan
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, West Virginia 26506, United States
| | - Talitha M. Selby
- Department of Mathematics and Natural Sciences, University of Wisconsin—Milwaukee, West Bend, Wisconsin 53095, United States
| | - F. Goulay
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, West Virginia 26506, United States
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44
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Nguyen HT, Mai TVT, Huynh LK. mHDFS-HoF: A generalized multilevel homodesmotic fragment-separation reaction based program for heat-of-formation calculation for acyclic hydrocarbons. J Comput Chem 2019; 40:1360-1373. [PMID: 30786057 DOI: 10.1002/jcc.25790] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Revised: 11/06/2018] [Accepted: 11/23/2018] [Indexed: 11/06/2022]
Abstract
Based on our modified classification of elemental species, a framework for automatic generation of multilevel Homodesmotic fragment-separation (mHDFS) reactions for chemical species was proposed. Combined the mHDFS framework with a database of heat of formation (HoF) and the calculated electronic structure data for the elemental mHD species, the mHDFS-HoF program was constructed in C/C++ language to calculate heat of formation for a species of interest on-the-fly. Using the electronic structure data calculated at CBS-QB3 level of theory for the elemental mHD species, applications and robustness of the code were discussed with several acyclic hydrocarbon systems including neutral and radical species. On-going work and extension to other systems were also discussed. The program and the supporting files can be freely downloaded at https://sites.google.com/view/mhdfs/. © 2019 Wiley Periodicals, Inc.
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Affiliation(s)
- Hieu Thanh Nguyen
- Molecular Science and Nano-Materials Laboratory, Institute for Computational Science and Technology, Ho Chi Minh city, Vietnam
| | - Tam Van-Thanh Mai
- Molecular Science and Nano-Materials Laboratory, Institute for Computational Science and Technology, Ho Chi Minh city, Vietnam.,Department of Theoretical and Physical Chemistry, University of Science, VNU-HCM, Ho Chi Minh city, Vietnam
| | - Lam Kim Huynh
- Chemical Engineering Department, International University, VNU-HCM, Vietnam
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45
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Park JJ, Han SY. Alternated Branching Ratios by Anomaly in Collision-Induced Dissociation of Proton-Bound Hoogsteen Base Pairs of 1-Methylcytosine with 1-Methylguanine and 9-Methylguanine. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2019; 30:846-854. [PMID: 30911905 DOI: 10.1007/s13361-019-02161-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2018] [Revised: 01/26/2019] [Accepted: 02/14/2019] [Indexed: 06/09/2023]
Abstract
A comparative study on the proton-bound complexes of 1-methylcytosine (1-mC) with 1-methylguanine (1-mG) and 9-methylguanine (9-mG), [1-mC:1-mG:H]+ and [1-mC:9-mG:H]+, respectively, was carried out using energy-resolved collision-induced dissociation (ER-CID) experiments in combination with quantum chemical calculations. In ER-CID experiments, the measured survival yields indicated an essentially identical stability for the two proton-bound complexes. In comparison with the lowest-energy structures and base-pairing energetics predicted at the B3LYP/6-311+G(2d,2p) theory level, both complexes produced in this study were suggested to be proton-bound Hoogsteen base pairs. Curiously, despite the similarity in structures, binding energetics, and potential energy surfaces predicted by the B3LYP theory, the fragment branching ratios exhibited an intriguing alternation between the two proton-bound Hoogsteen base pairs. The CID of [1-mC:1-mG:H]+ produced protonated cytosines, [1-mC:H]+, more abundantly than [1-mG:H]+, whereas that of [1-mC:9-mG:H]+ gave rise to a more pronounced production of protonated guanines, [9-mG:H]+. However, using the proton affinities of moieties predicted by the high-accuracy methods, including CBS-QB3 and the Guassian-4 theory, the anomaly known for [Cytosine:Guanine:H]+ (J. Am. Soc. Mass Spectrom. 29, 2368-2379 (2018)) successfully accounted for the alternated branching ratios. Thereby, the anomaly, more specifically, the production of proton-transferred fragments of O-protonated cytosines in the CID of proton-bound Hoogsteen base pairs, is indeed real, which is disclosed as the alternated branching ratios in the CID spectra of [1-mC:1-mG:H]+ and [1-mC:9-mG:H]+ in this study. Graphical Abstract .
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Affiliation(s)
- Jeong Ju Park
- Department of Nanochemistry, Gachon University, 1342 Seongnam-daero, Sujeong-gu, Seongnam-si, Gyeonggi-do, 13120, Republic of Korea
| | - Sang Yun Han
- Department of Nanochemistry, Gachon University, 1342 Seongnam-daero, Sujeong-gu, Seongnam-si, Gyeonggi-do, 13120, Republic of Korea.
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46
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Debnath S, Sengupta A, Raghavachari K. Eliminating Systematic Errors in DFT via Connectivity-Based Hierarchy: Accurate Bond Dissociation Energies of Biodiesel Methyl Esters. J Phys Chem A 2019; 123:3543-3550. [DOI: 10.1021/acs.jpca.9b01478] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Sibali Debnath
- Department of Chemistry, Indiana University, Bloomington, Indiana 47405, United States
| | - Arkajyoti Sengupta
- Department of Chemistry, Indiana University, Bloomington, Indiana 47405, United States
| | - Krishnan Raghavachari
- Department of Chemistry, Indiana University, Bloomington, Indiana 47405, United States
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47
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Lai L, Khanniche S, Green WH. Thermochemistry and Group Additivity Values for Fused Two-Ring Species and Radicals. J Phys Chem A 2019; 123:3418-3428. [DOI: 10.1021/acs.jpca.9b01065] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Lawrence Lai
- Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - Sarah Khanniche
- Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - William H. Green
- Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
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48
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Nielsen CBO, Pedersen AH, Hammerum S. Possible Intermediacy of Cyclopropane Complexes in the Isomerization of Aliphatic Amine Radical Cations. J Phys Chem A 2019; 123:1548-1557. [DOI: 10.1021/acs.jpca.8b10523] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Christian B. O. Nielsen
- Department of Chemistry, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen Ø, Denmark
| | - Anders H. Pedersen
- Department of Chemistry, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen Ø, Denmark
| | - Steen Hammerum
- Department of Chemistry, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen Ø, Denmark
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49
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Basis Set Effects in the Description of the Cl-O Bond in ClO and XClO/ClOX Isomers (X = H, O, and Cl) Using DFT and CCSD(T) Methods. J CHEM-NY 2019. [DOI: 10.1155/2019/4057848] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The performance of a group of density functional methods of progressive complexity for the description of the ClO bond in a series of chlorine oxides was investigated. The simplest ClO radical species and the two isomeric structures XClO/ClOX for each X = H, Cl, and O were studied using the PW91, TPSS, B3LYP, PBE0, M06, M06-2X, BMK, and B2PLYP functionals. Geometry optimizations and reaction enthalpies and enthalpies of formation for each species were calculated using Pople basis sets and the (aug)-cc-pVnZ Dunning sets, with n = D, T, Q, 5, and 6. For the calculation of enthalpies of formation, atomization and isodesmic reactions were employed. Both the precision of the methods with respect to the increase of the basis sets, as well as their accuracy, were gauged by comparing the results with the more accurate CCSD(T) calculations, performed using the same basis sets as for the DFT methods. The results obtained employing composite chemical methods (G4, CBS-QB3, and W1BD) were also used for the comparisons, as well as the experimental results when they are available. The results obtained show that error compensation is the key for successful description of molecular properties (geometries and energies) by carefully selecting the method and basis sets. In general, expansion of the one-electron basis set to the limit of completeness does not improve results at the DFT level, but just the opposite. The enthalpies of formation calculated at the CCSD(T)/aug-cc-pV6Z for the species considered are generally in agreement with experimental determinations and the most accurate theoretical values. Different sources of error in the calculations are discussed in detail.
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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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