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García-Ruiz P, Salas I, Casanova E, Bilbao R, Alzueta MU. Experimental and Modeling High-Pressure Study of Ammonia-Methane Oxidation in a Flow Reactor. ENERGY & FUELS : AN AMERICAN CHEMICAL SOCIETY JOURNAL 2024; 38:1399-1415. [PMID: 38264622 PMCID: PMC10804275 DOI: 10.1021/acs.energyfuels.3c03959] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/11/2023] [Revised: 12/21/2023] [Accepted: 12/21/2023] [Indexed: 01/25/2024]
Abstract
The present work deals with an experimental and modeling analysis of the oxidation of ammonia-methane mixtures at high pressure (up to 40 bar) in the 550-1250 K temperature range using a quartz tubular reactor and argon as a diluent. The impact of temperature, pressure, oxygen stoichiometry, and CH4/NH3 ratio has been analyzed on the concentrations of NH3, NO2, N2O, NO, N2, HCN, CH4, CO, and CO2 obtained as main products of the ammonia-methane mixture oxidation. The main results obtained indicate that increasing either the pressure, CH4/NH3 ratio, or stoichiometry results in a shift of NH3 and CH4 conversion to lower temperatures. The effect of pressure is particularly significant in the low range of pressures studied. The main products of ammonia oxidation are N2, NO, and N2O while NO2 concentrations are below the detection limit for all of the conditions considered. The N2O formation is favored by increasing the CH4/NH3 ratio and stoichiometry. The experimental results are simulated and interpreted in terms of an updated detailed chemical kinetic mechanism, which, in general, is able to describe well the conversion of both NH3 and CH4 under almost all of the studied conditions. Nevertheless, some discrepancies are found between the experimental results and model calculations.
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Affiliation(s)
- Pedro García-Ruiz
- Department of Chemical and
Environmental Engineering, Aragón Institute of Engineering
Research (I3A), University of Zaragoza, 50018 Zaragoza, Spain
| | - Iris Salas
- Department of Chemical and
Environmental Engineering, Aragón Institute of Engineering
Research (I3A), University of Zaragoza, 50018 Zaragoza, Spain
| | - Eva Casanova
- Department of Chemical and
Environmental Engineering, Aragón Institute of Engineering
Research (I3A), University of Zaragoza, 50018 Zaragoza, Spain
| | - Rafael Bilbao
- Department of Chemical and
Environmental Engineering, Aragón Institute of Engineering
Research (I3A), University of Zaragoza, 50018 Zaragoza, Spain
| | - María U. Alzueta
- Department of Chemical and
Environmental Engineering, Aragón Institute of Engineering
Research (I3A), University of Zaragoza, 50018 Zaragoza, Spain
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Abstract
Combustion is a reactive oxidation process that releases energy bound in chemical compounds used as fuels─energy that is needed for power generation, transportation, heating, and industrial purposes. Because of greenhouse gas and local pollutant emissions associated with fossil fuels, combustion science and applications are challenged to abandon conventional pathways and to adapt toward the demand of future carbon neutrality. For the design of efficient, low-emission processes, understanding the details of the relevant chemical transformations is essential. Comprehensive knowledge gained from decades of fossil-fuel combustion research includes general principles for establishing and validating reaction mechanisms and process models, relying on both theory and experiments with a suite of analytic monitoring and sensing techniques. Such knowledge can be advantageously applied and extended to configure, analyze, and control new systems using different, nonfossil, potentially zero-carbon fuels. Understanding the impact of combustion and its links with chemistry needs some background. The introduction therefore combines information on exemplary cultural and technological achievements using combustion and on nature and effects of combustion emissions. Subsequently, the methodology of combustion chemistry research is described. A major part is devoted to fuels, followed by a discussion of selected combustion applications, illustrating the chemical information needed for the future.
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Jupp AR. Evidence for the encounter complex in frustrated Lewis pair chemistry. Dalton Trans 2022; 51:10681-10689. [PMID: 35412552 DOI: 10.1039/d2dt00655c] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Frustrated Lewis Pairs (FLPs) are combinations of bulky Lewis acids and bases that can carry out small-molecule activation and catalysis. Mechanistically, the reaction of the acid, base and substrate involves the collision of three distinct molecules, and so the pre-association of the acid and base to form an encounter complex has been proposed. This article will examine the evidence for the formation of this encounter complex, focusing on the archetypal main-group combinations P(tBu)3/B(C6F5)3 and PMes3/B(C6F5)3 (Mes = mesityl), and includes quantum chemical calculations, molecular dynamics simulations, NMR spectroscopic measurements and neutron scattering. Furthermore, the recent discovery that the associated acid and base can absorb a photon to promote single-electron transfer has enabled the encounter complex to also be studied by UV-Vis spectroscopy, EPR spectroscopy, transient absorption spectroscopy, and resonance Raman spectroscopy. These data all support the notion that the encounter complex is only weakly held together and in low concentration in solution. The insights that these studies provide underpin the exciting transformations that can be promoted by FLPs. Finally, some observations and unanswered questions are provided to prompt further study in this field.
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Affiliation(s)
- Andrew R Jupp
- School of Chemistry, University of Birmingham, Edgbaston, Birmingham, West Midlands, B15 2TT, UK.
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Burke MP, Meng Q, Sabaitis C. Dissociation-Induced Depletion of High-Energy Reactant Molecules as a Mechanism for Pressure-Dependent Rate Constants for Bimolecular Reactions. Faraday Discuss 2022; 238:355-379. [DOI: 10.1039/d2fd00054g] [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
In 1922, Lindemann proposed the now-well-known mechanism for pressure-dependent rate constants for unimolecular reactions: reactant molecules with sufficiently high energies dissociate more quickly than collisions can reestablish the Boltzmann distribution...
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Klippenstein SJ. Spiers Memorial Lecture: theory of unimolecular reactions. Faraday Discuss 2022; 238:11-67. [DOI: 10.1039/d2fd00125j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
One hundred years ago, at an earlier Faraday Discussion meeting, Lindemann presented a mechanism that provides the foundation for contemplating the pressure dependence of unimolecular reactions. Since that time, our...
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Lei L, Burke MP. Understanding and Representing the Distinct Kinetics Induced by Reactive Collisions of Rovibrationally Excited Ephemeral Complexes across Reactive Collider Mole Fractions and Pressures. J Phys Chem A 2020; 124:10937-10953. [DOI: 10.1021/acs.jpca.0c08690] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Lei Lei
- Department of Mechanical Engineering, Columbia University, New York, New York 10027, United States
| | - Michael P. Burke
- Department of Mechanical Engineering, Columbia University, New York, New York 10027, United States
- Department of Chemical Engineering, Data Science Institute, Columbia University, New York, New York 10027, United States
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Affiliation(s)
- William H. Green
- Department of Chemical Engineering Massachusetts Institute of Technology Cambridge Massachusetts USA
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8
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Water Catalysis of the Reaction of Methanol with OH Radical in the Atmosphere is Negligible. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202001065] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Bertels LW, Newcomb LB, Alaghemandi M, Green JR, Head-Gordon M. Benchmarking the Performance of the ReaxFF Reactive Force Field on Hydrogen Combustion Systems. J Phys Chem A 2020; 124:5631-5645. [DOI: 10.1021/acs.jpca.0c02734] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Affiliation(s)
- Luke W. Bertels
- Department of Chemistry, University of California, Berkeley, California 94720, United States
| | - Lucas B. Newcomb
- Department of Chemistry, University of Massachusetts Boston, Boston, Massachusetts 02125, United States
| | - Mohammad Alaghemandi
- Department of Chemistry, University of Massachusetts Boston, Boston, Massachusetts 02125, United States
| | - Jason R. Green
- Department of Chemistry, University of Massachusetts Boston, Boston, Massachusetts 02125, United States
- Department of Physics, University of Massachusetts Boston, Boston, Massachusetts 02125, United States
| | - Martin Head-Gordon
- Department of Chemistry, University of California, Berkeley, California 94720, United States
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
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Frank I, Siekmann D. First‐Principles Simulation of Highly Reactive Systems: Immediacy on a Femtosecond Time Scale. ChemistrySelect 2020. [DOI: 10.1002/slct.202000574] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Irmgard Frank
- Universität Hannover Theoretische Chemie, Callinstr. 3 A 30167 Hannover Germany
| | - Dirk Siekmann
- Universität Hannover Theoretische Chemie, Callinstr. 3 A 30167 Hannover Germany
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Wu J, Gao LG, Varga Z, Xu X, Ren W, Truhlar DG. Water Catalysis of the Reaction of Methanol with OH Radical in the Atmosphere is Negligible. Angew Chem Int Ed Engl 2020; 59:10826-10830. [DOI: 10.1002/anie.202001065] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Revised: 02/23/2020] [Indexed: 11/07/2022]
Affiliation(s)
- Junjun Wu
- Department of Mechanical and Automation Engineering & Shenzhen Research Institute The Chinese University of Hong Kong New Territories Hong Kong SAR China
| | - Lu Gem Gao
- Center for Combustion Energy Department of Energy and Power Engineering Key Laboratory for Thermal Science and Power Engineering of Ministry of Education Tsinghua University Beijing China
| | - Zoltan Varga
- Department of Chemistry, Chemical Theory Center and Supercomputing Institute University of Minnesota Minneapolis USA
| | - Xuefei Xu
- Center for Combustion Energy Department of Energy and Power Engineering Key Laboratory for Thermal Science and Power Engineering of Ministry of Education Tsinghua University Beijing China
| | - Wei Ren
- Department of Mechanical and Automation Engineering & Shenzhen Research Institute The Chinese University of Hong Kong New Territories Hong Kong SAR China
| | - Donald G. Truhlar
- Department of Chemistry, Chemical Theory Center and Supercomputing Institute University of Minnesota Minneapolis USA
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Robertson C, Ismail I, Habershon S. Traversing Dense Networks of Elementary Chemical Reactions to Predict Minimum‐Energy Reaction Mechanisms. CHEMSYSTEMSCHEM 2019. [DOI: 10.1002/syst.201900047] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Christopher Robertson
- Department of Chemistry and Centre for Scientific Computing University of Warwick Coventry CV4 7AL United Kingdom
| | - Idil Ismail
- Department of Chemistry and Centre for Scientific Computing University of Warwick Coventry CV4 7AL United Kingdom
| | - Scott Habershon
- Department of Chemistry and Centre for Scientific Computing University of Warwick Coventry CV4 7AL United Kingdom
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Nagy T, Tóth J, Ladics T. Automatic kinetic model generation and selection based on concentration versus time curves. INT J CHEM KINET 2019. [DOI: 10.1002/kin.21335] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- Tibor Nagy
- Institute of Materials and Environmental ChemistryResearch Centre for Natural SciencesHungarian Academy of SciencesBudapest Hungary
- Laboratory for Chemical KineticsEötvös Loránd UniversityBudapest Hungary
| | - János Tóth
- Laboratory for Chemical KineticsEötvös Loránd UniversityBudapest Hungary
- Department of Mathematical AnalysisBudapest University of Technology and EconomicsBudapest Hungary
| | - Tamás Ladics
- Department of Science and EngineeringJohn von Neumann UniversityKecskemét Hungary
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Jasper AW, Sivaramakrishnan R, Klippenstein SJ. Nonthermal rate constants for CH 4 * + X → CH 3 + HX, X = H, O, OH, and O 2. J Chem Phys 2019; 150:114112. [PMID: 30902010 DOI: 10.1063/1.5090394] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Quasiclassical trajectories are used to compute nonthermal rate constants, k*, for abstraction reactions involving highly-excited methane CH4 * and the radicals H, O, OH, and O2. Several temperatures and internal energies of methane, Evib, are considered, and significant nonthermal rate enhancements for large Evib are found. Specifically, when CH4 * is internally excited close to its dissociation threshold (Evib ≈ D0 = 104 kcal/mol), its reactivity with H, O, and OH is shown to be collision-rate-limited and to approach that of comparably-sized radicals, such as CH3, with k* > 10-10 cm3 molecule-1 s-1. Rate constants this large are more typically associated with barrierless reactions, and at 1000 K, this represents a nonthermal rate enhancement, k*/k, of more than two orders of magnitude relative to thermal rate constants k. We show that large nonthermal rate constants persist even after significant internal cooling, with k*/k > 10 down to Evib ≈ D0/4. The competition between collisional cooling and nonthermal reactivity is studied using a simple model, and nonthermal reactions are shown to account for up to 35%-50% of the fate of the products of H + CH3 = CH4 * under conditions of practical relevance to combustion. Finally, the accuracy of an effective temperature model for estimating k* from k is quantified.
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Affiliation(s)
- Ahren W Jasper
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - Raghu Sivaramakrishnan
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - Stephen J Klippenstein
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Argonne, Illinois 60439, USA
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Chen E, Yang Q, Dufour-Décieux V, Sing-Long CA, Freitas R, Reed EJ. Transferable Kinetic Monte Carlo Models with Thousands of Reactions Learned from Molecular Dynamics Simulations. J Phys Chem A 2019; 123:1874-1881. [DOI: 10.1021/acs.jpca.8b09947] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Enze Chen
- Institute for Computational and Mathematical Engineering, Stanford University, Stanford, California 94305, United States
| | - Qian Yang
- Computer Science and Engineering Department, University of Connecticut, Storrs, Connecticut 06269, United States
| | - Vincent Dufour-Décieux
- Department of Materials Science and Engineering, Stanford University, Stanford, California 94305, United States
| | - Carlos A. Sing-Long
- Institute for Mathematical and Computational Engineering, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Rodrigo Freitas
- Department of Materials Science and Engineering, Stanford University, Stanford, California 94305, United States
| | - Evan J. Reed
- Department of Materials Science and Engineering, Stanford University, Stanford, California 94305, United States
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16
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Lei L, Burke MP. Bath Gas Mixture Effects on Multichannel Reactions: Insights and Representations for Systems beyond Single-Channel Reactions. J Phys Chem A 2018; 123:631-649. [DOI: 10.1021/acs.jpca.8b10581] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Lei Lei
- Department of Mechanical Engineering, Columbia University, New York, New York 10027, United States
| | - Michael P. Burke
- Department of Mechanical Engineering, Department of Chemical Engineering, Data Science Institute, Columbia University, New York, New York 10027, United States
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Cavallotti C, Pelucchi M, Georgievskii Y, Klippenstein SJ. EStokTP: Electronic Structure to Temperature- and Pressure-Dependent Rate Constants—A Code for Automatically Predicting the Thermal Kinetics of Reactions. J Chem Theory Comput 2018; 15:1122-1145. [DOI: 10.1021/acs.jctc.8b00701] [Citation(s) in RCA: 57] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- C. Cavallotti
- Department of Chemistry, Materials and Chemical Engineering “G. Natta”, Politecnico di Milano, Milan, Italy
| | - M. Pelucchi
- Department of Chemistry, Materials and Chemical Engineering “G. Natta”, Politecnico di Milano, Milan, Italy
| | - Y. Georgievskii
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Argonne, Illinois 60439, United States
| | - S. J. Klippenstein
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Argonne, Illinois 60439, United States
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