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Belghiti A, Mahmoudi M, Catoire L, Diévart P. Reassessment of the High-Temperature Oxidation of Di Ethyl Ether through Ab Initio Calculations. J Phys Chem A 2024. [PMID: 39248814 DOI: 10.1021/acs.jpca.4c03356] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/10/2024]
Abstract
Recent investigations of diethyl ether (DEE) high-temperature pyrolysis and fuel-rich oxidation have highlighted the failure of existing kinetic models to describe experimental CO production. The DEE high-temperature pyrolysis and oxidation chemistry is thus investigated through ab initio calculations. Geometries, frequencies, and hindered-rotor potentials of reactants, products, and transition states of key reactions (fuel decomposition radical decomposition and H-abstraction reactions) are calculated with the B2PLYP-D3/def2-TZVPD method, whereas final energies are refined using CCSD(T)/aug-cc-pV(D,T)Z. Temperature- and pressure-dependent rate constants are then derived from either canonical transition state theory (CTST) or ME/RRKM analysis with the inclusion of tunneling effect and hindered-rotor corrections and compared to experimental measurements when available as well as to previously suggested values. This new information is then merged with a C0-C3 core chemistry model and a low-temperature chemistry DEE subset from the literature to propose a new kinetic model for the combustion of DEE. This model is tested successfully against a large database related to the high-temperature oxidation and pyrolysis chemistry of DEE, including ignition delay times, shock tube speciation data, time-resolved CO profiles, laminar flame speeds, flame structures, and jet-stirred reactor data.
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Affiliation(s)
- Asmae Belghiti
- Unité de Chimie et des Procédés (UCP), ENSTA Paris, Institut Polytechnique de Paris, 91120 Palaiseau, France
| | - Marwa Mahmoudi
- Unité de Chimie et des Procédés (UCP), ENSTA Paris, Institut Polytechnique de Paris, 91120 Palaiseau, France
| | - Laurent Catoire
- Unité de Chimie et des Procédés (UCP), ENSTA Paris, Institut Polytechnique de Paris, 91120 Palaiseau, France
- ICARE-CNRS, 1C, Avenue de la Recherche Scientifique, 45071 Orléans Cedex 2, France
| | - Pascal Diévart
- Unité de Chimie et des Procédés (UCP), ENSTA Paris, Institut Polytechnique de Paris, 91120 Palaiseau, France
- ICARE-CNRS, 1C, Avenue de la Recherche Scientifique, 45071 Orléans Cedex 2, France
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Carpenter BK, Ellison GB, Nimlos MR, Scheer AM. A Conical Intersection Influences the Ground State Rearrangement of Fulvene to Benzene. J Phys Chem A 2022; 126:1429-1447. [PMID: 35191307 DOI: 10.1021/acs.jpca.2c00038] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The rearrangement of fulvene to benzene is believed to play an important role in the formation of soot during hydrocarbon combustion. Previous work has identified two possible mechanisms for the rearrangement─a unimolecular path and a hydrogen-atom-assisted, bimolecular path. Computational results to date have suggested that the unimolecular mechanism faces a barrier of about 74 kcal/mol, which makes it unable to compete with the bimolecular mechanism under typical combustion conditions. This computed barrier is about 10 kcal/mol higher than the experimental value, which is an unusually large discrepancy for modern electronic structure theory. In the present work, we have reinvestigated the unimolecular mechanism computationally, and we have found a second transition state that is approximately 10 kcal/mol lower in energy than the previously identified one and, therefore, in excellent agreement with the experimental value. The existence of two transition states for the same rearrangement arises because there is a conical intersection between the two lowest singlet states which occurs in the vicinity of the reaction coordinates. The two possible paths around the cone on the lower adiabatic surface give rise to the two distinct saddle points. The lower barrier for the unimolecular mechanism now makes it competitive with the bimolecular one, according to our calculations. In support of this conclusion, we have reanalyzed some previous experimental results on anisole pyrolysis, which leads to benzene as a significant product and have shown that the unimolecular and bimolecular mechanisms for fulvene → benzene must be occurring competitively in that system. Finally, we have identified that similar conical intersections arise during the isomerizations of benzofulvene and isobenzofulvene to naphthalene.
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Affiliation(s)
- Barry K Carpenter
- School of Chemistry, Cardiff University, Main Building, Park PL, Cardiff CF10 3AT, U.K
| | - G Barney Ellison
- Department of Chemistry, University of Colorado, Boulder, Colorado 80309, United States
| | - Mark R Nimlos
- National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, Colorado 80401, United States
| | - Adam M Scheer
- Recurve Inc., 4014 South Lemay Avenue, Unit 22, Fort Collins, Colorado 80525, United States
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Sela P, Sakai Y, Choi HS, Herzler J, Fikri M, Schulz C, Peukert S. High-Temperature Unimolecular Decomposition of Diethyl Ether: Shock-Tube and Theory Studies. J Phys Chem A 2019; 123:6813-6827. [PMID: 31329437 DOI: 10.1021/acs.jpca.9b04186] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The unimolecular decomposition of diethyl ether (DEE; C2H5OC2H5) is considered to be initiated via a molecular elimination and a C-O and a C-C bond fission step: C2H5OC2H5 → C2H4 + C2H5OH (1), C2H5OC2H5 → C2H5 + C2H5O (2), and C2H5OC2H5 → CH3 + C2H5OCH2 (3). In this work, two shock-tube facilities were used to investigate these reactions via (a) time-resolved H-atom concentration measurements by H-ARAS (atomic resonance absorption spectrometry), (b) time-resolved DEE-concentration measurements by high repetition-rate time-of-flight mass spectrometry (HRR-TOF-MS), and (c) product-composition measurements via gas chromatography/MS (GC/MS) after quenching the test gas. The experiments were conducted at temperatures ranging from 1054 to 1505 K and at pressures between 1.2 and 2.5 bar. Initial DEE mole fractions between 0.4 and 9300 ppm were used to perform the kinetics experiments by H-ARAS (0.4 ppm), GC/MS (200-500 ppm), and HRR-TOF-MS (7850-9300 ppm). The rate constants, ktotal (ktotal = k1 + k2 + k3) derived from the GC/MS and HRR-TOF-MS experiments agree well with each other and can be described by the Arrhenius expression, ktotal(1054-1467 K; 1.3-2.5 bar) = 1012.81±0.22 exp(-240.27 ± 5.11 kJ mol-1/RT) s-1. From the H-ARAS experiments, overall rate constants for the bond fission channels, k2+3 = k2 + k3 have been extracted. The k2+3 data can be well described by the Arrhenius equation, k2+3(1299-1505 K; 1.3-2.5 bar) = 1014.43±0.33 exp(-283.27 ± 8.78 kJ mol-1/RT) s-1. A master-equation analysis was performed using CCSD(T)/aug-cc-pvtz//B3LYP/aug-cc-pvtz and CASPT2/aug-cc-pvtz//B3LYP/aug-cc-pvtz molecular properties and energies for the three primary thermal decomposition processes in DEE. The derived experimental data is very well reproduced by the simulations with the mechanism of this work. With regard to the branching ratios between bond fissions and elimination channels, uncertainties remain.
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Affiliation(s)
- Paul Sela
- IVG, Institute for Combustion and Gas Dynamics-Reactive Fluids and CENIDE, Center for Nanointegration Duisburg-Essen , University of Duisburg-Essen , 47048 Duisburg , Germany
| | - Yasuyuki Sakai
- Graduate School of Engineering , University of Fukui , Fukui 910-8507 , Japan
| | - Hang Seok Choi
- IVG, Institute for Combustion and Gas Dynamics-Reactive Fluids and CENIDE, Center for Nanointegration Duisburg-Essen , University of Duisburg-Essen , 47048 Duisburg , Germany
| | - Jürgen Herzler
- IVG, Institute for Combustion and Gas Dynamics-Reactive Fluids and CENIDE, Center for Nanointegration Duisburg-Essen , University of Duisburg-Essen , 47048 Duisburg , Germany
| | - Mustapha Fikri
- IVG, Institute for Combustion and Gas Dynamics-Reactive Fluids and CENIDE, Center for Nanointegration Duisburg-Essen , University of Duisburg-Essen , 47048 Duisburg , Germany
| | - Christof Schulz
- IVG, Institute for Combustion and Gas Dynamics-Reactive Fluids and CENIDE, Center for Nanointegration Duisburg-Essen , University of Duisburg-Essen , 47048 Duisburg , Germany
| | - Sebastian Peukert
- IVG, Institute for Combustion and Gas Dynamics-Reactive Fluids and CENIDE, Center for Nanointegration Duisburg-Essen , University of Duisburg-Essen , 47048 Duisburg , Germany
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Mebel AM, Kaiser RI. Formation of resonantly stabilised free radicals via the reactions of atomic carbon, dicarbon, and tricarbon with unsaturated hydrocarbons: theory and crossed molecular beams experiments. INT REV PHYS CHEM 2015. [DOI: 10.1080/0144235x.2015.1075280] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- Alexander M. Mebel
- Department of Chemistry and Biochemistry, Florida International University, Miami, FL 33199, USA
| | - Ralf I. Kaiser
- Department of Chemistry, University of Hawaii at Manoa, Honolulu, HI 96822, USA
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Tokoyama H, Yamakado H, Maeda S, Ohno K. Isomers of Benzene on Its Global Network of Reaction Pathways. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 2015. [DOI: 10.1246/bcsj.20150088] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
| | | | | | - Koichi Ohno
- Institute for Quantum Chemical Exploration
- Graduate School of Science, Tohoku University
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Tokoyama H, Yamakado H, Maeda S, Ohno K. Exploration of Isomers of Benzene by GRRM/SCC-DFTB. CHEM LETT 2014. [DOI: 10.1246/cl.140024] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
| | | | | | - Koichi Ohno
- Institute for Quantum Chemical Exploration
- Graduate School of Science, Tohoku University
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Hopf H, Markopoulos G. The chemistry of bisallenes. Beilstein J Org Chem 2012; 8:1936-98. [PMID: 23209534 PMCID: PMC3511034 DOI: 10.3762/bjoc.8.225] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2012] [Accepted: 10/13/2012] [Indexed: 11/23/2022] Open
Abstract
This review describes the preparation, structural properties and the use of bisallenes in organic synthesis for the first time. All classes of compounds containing at least two allene moieties are considered, starting from simple conjugated bisallenes and ending with allenes in which the two cumulenic units are connected by complex polycyclic ring systems, heteroatoms and/or heteroatom-containing tethers. Preparatively the bisallenes are especially useful in isomerization and cycloaddition reactions of all kinds leading to the respective target molecules with high atom economy and often in high yield. Bisallenes are hence substrates for generating molecular complexity in a small number of steps (high step economy).
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Affiliation(s)
- Henning Hopf
- Institute of Organic Chemistry, Technical University of Braunschweig, Hagenring 30, D-38106 Braunschweig, Germany, fax: +49-(0)531-391-5388
| | - Georgios Markopoulos
- Institute of Organic Chemistry, Technical University of Braunschweig, Hagenring 30, D-38106 Braunschweig, Germany, fax: +49-(0)531-391-5388
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Chapter 7 Pyrolysis of Hydrocarbons. ACTA ACUST UNITED AC 2010. [DOI: 10.1016/s0167-9244(09)02807-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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