1
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Mao C, Zhao K, Loong CFJ, Song D, Lisak G. A New Discovery on the Potential Stability of Ion-Selective Membranes: The Poison from Tetrahydrofuran. ACS Sens 2024. [PMID: 39115965 DOI: 10.1021/acssensors.4c01673] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/10/2024]
Abstract
Ion-selective electrodes (ISEs) have widespread use in the fields of clinical and environmental analyses. Tetrahydrofuran (THF) is the most used solvent for the preparation of modern ISEs, equipped with ion-selective membranes (ISMs). Until now, the influence of impurities in THF toward potentiometric instability of ion-selective membrane based ISEs was probably associated with the presence of either residual water or peroxide. To address this issue, most literature recommends redistilling THF prior to use in the preparation of the potentiometric membranes. Current study reveals that the actual THF impurity that is responsible for potential instability in the ISM includes products from the oxidation of THF, which contains the hydroxyl group and possibly carbonyl group with a boiling point of above 200 °C. The density functional theory calculation supported pathway of the chemical reaction of THF oxidation, hence, the chemical structure of the uncertain impurities was predicted. The underlying reason for the deteriorating potential stability of the ISEs is proposed as the significant hydrophilicity of these impurities that affect the partitioning of the ion sensing components in the membrane, thus enhancing the leaching of the membrane components from the membrane phase. This finding explains why redistillation of aged THF is advised.
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Affiliation(s)
- Canwei Mao
- Residues and Resource Reclamation Centre (R3C), Nanyang Environment and Water Research Institute, Nanyang Technological University, 1 Cleantech Loop, CleanTech One, 637141 Singapore
| | - Ke Zhao
- Residues and Resource Reclamation Centre (R3C), Nanyang Environment and Water Research Institute, Nanyang Technological University, 1 Cleantech Loop, CleanTech One, 637141 Singapore
- School of Civil and Environmental Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798 Singapore
| | - Cyrus Foo Jit Loong
- Residues and Resource Reclamation Centre (R3C), Nanyang Environment and Water Research Institute, Nanyang Technological University, 1 Cleantech Loop, CleanTech One, 637141 Singapore
| | - Dean Song
- Tobacco Research Institute, Chinese Academy of Agricultural Sciences, Qingdao 266101, China
| | - Grzegorz Lisak
- Residues and Resource Reclamation Centre (R3C), Nanyang Environment and Water Research Institute, Nanyang Technological University, 1 Cleantech Loop, CleanTech One, 637141 Singapore
- School of Civil and Environmental Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798 Singapore
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2
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Demireva M, Au K, Hansen N, Sheps L. Time-resolved quantification of key species and mechanistic insights in low-temperature tetrahydrofuran oxidation. Phys Chem Chem Phys 2024; 26:10357-10368. [PMID: 38502092 DOI: 10.1039/d3cp06227a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/20/2024]
Abstract
We investigate the kinetics and report the time-resolved concentrations of key chemical species in the oxidation of tetrahydrofuran (THF) at 7500 torr and 450-675 K. Experiments are carried out using high-pressure multiplexed photoionization mass spectrometry (MPIMS) combined with tunable vacuum ultraviolet radiation from the Berkely Lab Advanced Light Source. Intermediates and products are quantified using reference photoionization (PI) cross sections, when available, and constrained by a global carbon balance tracking approach at all experimental temperatures simultaneously for the species without reference cross sections. From carbon balancing, we determine time-resolved concentrations for the ROO˙ and ˙OOQOOH radical intermediates, butanedial, and the combined concentration of ketohydroperoxide (KHP) and unsaturated hydroperoxide (UHP) products stemming from the ˙QOOH + O2 reaction. Furthermore, we quantify a product that we tentatively assign as fumaraldehyde, which arises from UHP decomposition via H2O or ˙OH + H loss. The experimentally derived species concentrations are compared with model predictions using the most recent literature THF oxidation mechanism of Fenard et al., (Combust. Flame, 2018, 191, 252-269). Our results indicate that the literature mechanism significantly overestimates THF consumption and the UHP + KHP concentration at our conditions. The model predictions are sensitive to the rate coefficient for the ROO˙ isomerization to ˙QOOH, which is the gateway for radical chain propagating and branching pathways. Comparisons with our recent results for cyclopentane (Demireva et al., Combust. Flame, 2023, 257, 112506) provide insights into the effect of the ether group on reactivity and highlight the need to determine accurate rate coefficients of ROO˙ isomerization and subsequent reactions.
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Affiliation(s)
- Maria Demireva
- Combustion Research Facility, Sandia National Laboratories, Livermore, California 94551, USA.
| | - Kendrew Au
- Combustion Research Facility, Sandia National Laboratories, Livermore, California 94551, USA.
| | - Nils Hansen
- Combustion Research Facility, Sandia National Laboratories, Livermore, California 94551, USA.
| | - Leonid Sheps
- Combustion Research Facility, Sandia National Laboratories, Livermore, California 94551, USA.
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3
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Cho J, Rösch D, Tao Y, Osborn DL, Klippenstein SJ, Sheps L, Sivaramakrishnan R. Modeling-Experiment-Theory Analysis of Reactions Initiated from Cl + Methyl Formate. J Phys Chem A 2023; 127:9804-9819. [PMID: 37937747 DOI: 10.1021/acs.jpca.3c05085] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2023]
Abstract
Methyl formate (MF; CH3OCHO) is the smallest representative of esters, which are common components of biodiesel. The present study characterizes the thermal dissociation kinetics of the radicals formed by H atom abstraction from MF─CH3OCO and CH2OCHO─through a combination of modeling, experiment, and theory. For the experimental effort, excimer laser photolysis of Cl2 was used as a source of Cl atoms to initiate reactions with MF in the gas phase. Time-resolved species profiles of MF, Cl2, HCl, CO2, CH3, CH3Cl, CH2O, and CH2ClOCHO were measured and quantified using photoionization mass spectrometry at temperatures of 400-750 K and 10 Torr. The experimental data were simulated using a kinetic model, which was informed by ab initio-based theoretical kinetics calculations and included chlorine chemistry and secondary reactions of radical decomposition products. We calculated the rate coefficients for the H-abstraction reactions Cl + MF → HCl + CH3OCO (R1a) and Cl + MF → HCl + CH2OCHO (R1b): k1a,theory = 6.71 × 10-15·T1.14·exp(-606/T) cm3/molecule·s; k1b,theory = 4.67 × 10-18·T2.21·exp(-245/T) cm3/molecule·s over T = 200-2000 K. Electronic structure calculations indicate that the barriers to CH3OCO and CH2OCHO dissociation are 13.7 and 31.6 kcal/mol and lead to CH3 + CO2 (R3) and CH2O + HCO (R5), respectively. The master equation-based theoretical rate coefficients are k3,theory (P = ∞) = 2.94 × 109·T1.21·exp(-6209/T) s-1 and k5,theory (P = ∞) = 8.45 × 108·T1.39·exp(-15132/T) s-1 over T = 300-1500 K. The calculated branching fractions into R1a and R1b and the rate coefficient for R5 were validated by modeling of the experimental species time profiles and found to be in excellent agreement with theory. Additionally, we found that the bimolecular reactions CH2OCHO + Cl, CH2OCHO + Cl2, and CH3 + Cl2 were critical to accurately model the experimental data and constrain the kinetics of MF-radicals. Inclusion of the kinetic parameters determined in this study showed a significant impact on combustion simulations of larger methyl esters, which are considered as biodiesel surrogates.
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Affiliation(s)
- Jaeyoung Cho
- Chemical Sciences & Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Daniel Rösch
- Combustion Research Facility, Sandia National Laboratories, Livermore, California 94551-0969, United States
| | - Yujie Tao
- Chemical Sciences & Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - David L Osborn
- Combustion Research Facility, Sandia National Laboratories, Livermore, California 94551-0969, United States
| | - Stephen J Klippenstein
- Chemical Sciences & Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Leonid Sheps
- Combustion Research Facility, Sandia National Laboratories, Livermore, California 94551-0969, United States
| | - Raghu Sivaramakrishnan
- Chemical Sciences & Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
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4
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Pham TV, Trang HTT. Mechanistic and Kinetic Approach on the Propargyl Radical (C 3H 3) with the Criegee Intermediate (CH 2OO). ACS OMEGA 2023; 8:16859-16868. [PMID: 37214685 PMCID: PMC10193399 DOI: 10.1021/acsomega.3c00491] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Accepted: 04/20/2023] [Indexed: 05/24/2023]
Abstract
The detailed reaction mechanism and kinetics of the C3H3 + CH2OO system have been thoroughly investigated. The CBS-QB3 method in conjunction with the ME/vRRKM theory has been applied to figure out the potential energy surface and rate constants for the C3H3 + CH2OO system. The C3H3 + CH2OO reaction leading to the CH2-[cyc-CCHCHOO] + H product dominates compared to the others. Rate constants of the reaction are dependent on temperatures (300-2000 K) and pressures (1-76,000 Torr), for which the rate constant of the channel C3H3 + CH2OO → CH2-[cyc-CCHCHOO] + H decreases at low pressures (1-76 Torr), but it increases with rising temperature if the pressure P ≥ 760 Torr. Rate constants of the three reaction channels C3H3 + CH2OO → CHCCH2CHO + OH, C3H3 + CH2OO → OCHCHCHCHO + H, and C3H3 + CH2OO → CHCHCHO + CH2O fluctuate with temperatures. The branching ratio of the C3H3 + CH2OO → CH2-[cyc-CCHCHOO] + H channel is the highest, accounting for 51-98.7% in the temperature range of 300-2000 K and 760 Torr pressure, while those of the channels forming the products PR10 (OCHCHCHCHO + H) and PR11 (CHCHCHO + CH2O) are the lowest, less than 0.1%, indicating that the contribution of these two reaction paths to the title reaction is insignificant. The proposed temperature- and pressure-dependent rate constants, together with the thermodynamic data of the species involved, can be confidently used for modeling CH2OO-related systems under atmospheric and combustion conditions.
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Affiliation(s)
- Tien V. Pham
- School
of Chemical Engineering, Hanoi University
of Science and Technology, Hanoi 100000, Vietnam
| | - Hoang T. T. Trang
- Department
of Chemistry, Hanoi Architectural University, Hanoi 100000, Vietnam
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5
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Doner AC, Zádor J, Rotavera B. Unimolecular Reactions of 2,4-Dimethyloxetanyl Radicals. J Phys Chem A 2023; 127:2591-2600. [PMID: 36898134 PMCID: PMC10041641 DOI: 10.1021/acs.jpca.2c08290] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/12/2023]
Abstract
Alkyl-substituted oxetanes are cyclic ethers formed via unimolecular reactions of QOOH radicals produced via a six-membered transition state in the preceding isomerization step of organic peroxy radicals, ROO. Owing to radical isomer-specific formation pathways, cyclic ethers are unambiguous proxies for inferring QOOH reaction rates. Therefore, accounting for subsequent oxidation of cyclic ethers is important in order to accurately determine rates for QOOH → products. Cyclic ethers can react via unimolecular reaction (ring-opening) or via bimolecular reaction with O2 to form cyclic ether-peroxy adducts. The computations herein provide reaction mechanisms and theoretical rate coefficients for the former type in order to determine competing pathways for the cyclic ether radicals. Rate coefficients of unimolecular reactions of 2,4-dimethyloxetanyl radicals were computed using master equation modeling from 0.01 to 100 atm and from 300 to 1000 K. Coupled-cluster methods were utilized for stationary-point energy calculations, and uncertainties in the computed rate coefficients were accounted for using variation in barrier heights and in well depths. The potential energy surfaces reveal accessible channels to several species via crossover reactions, such as 2-methyltetrahydrofuran-5-yl and pentanonyl isomers. For the range of temperature over which 2,4-dimethyloxetane forms during n-pentane oxidation, the following are the major channels: 2,4-dimethyloxetan-1-yl → acetaldehyde + allyl, 2,4-dimethyloxetan-2-yl → propene + acetyl, and 2,4-dimethyloxetan-3-yl → 3-butenal + methyl, or, 1-penten-3-yl-4-ol. Well-skipping reactions were significant in a number of channels and also exhibited a markedly different pressure dependence. The calculations show that rate coefficients for ring-opening are approximately an order of magnitude lower for the tertiary 2,4-dimethyloxetanyl radicals than for the primary and secondary 2,4-dimethyloxetanyl radicals. Unlike for reactions of the corresponding ROO radicals, however, unimolecular rate coefficients are independent of the stereochemistry. Moreover, rate coefficients of cyclic ether radical ring-opening are of the same order of magnitude as O2 addition, underscoring the point that a competing network of reactions is necessary to include for accurate chemical kinetics modeling of species profiles for cyclic ethers.
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Affiliation(s)
| | - Judit Zádor
- Combustion Research Facility, Sandia National Laboratories, Livermore, California 94550, United States
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6
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Zádor J, Martí C, Van de Vijver R, Johansen SL, Yang Y, Michelsen HA, Najm HN. Automated Reaction Kinetics of Gas-Phase Organic Species over Multiwell Potential Energy Surfaces. J Phys Chem A 2023; 127:565-588. [PMID: 36607817 DOI: 10.1021/acs.jpca.2c06558] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Automation of rate-coefficient calculations for gas-phase organic species became possible in recent years and has transformed how we explore these complicated systems computationally. Kinetics workflow tools bring rigor and speed and eliminate a large fraction of manual labor and related error sources. In this paper we give an overview of this quickly evolving field and illustrate, through five detailed examples, the capabilities of our own automated tool, KinBot. We bring examples from combustion and atmospheric chemistry of C-, H-, O-, and N-atom-containing species that are relevant to molecular weight growth and autoxidation processes. The examples shed light on the capabilities of automation and also highlight particular challenges associated with the various chemical systems that need to be addressed in future work.
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Affiliation(s)
- Judit Zádor
- Combustion Research Facility, Sandia National Laboratories, Livermore94550, California, United States
| | - Carles Martí
- Combustion Research Facility, Sandia National Laboratories, Livermore94550, California, United States
| | | | - Sommer L Johansen
- Combustion Research Facility, Sandia National Laboratories, Livermore94550, California, United States
| | - Yoona Yang
- Combustion Research Facility, Sandia National Laboratories, Livermore94550, California, United States
| | - Hope A Michelsen
- Department of Mechanical Engineering, University of Colorado Boulder, Boulder80309, Colorado, United States
| | - Habib N Najm
- Combustion Research Facility, Sandia National Laboratories, Livermore94550, California, United States
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7
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Couch DE, Mulvihill CR, Sivaramakrishnan R, Au K, Taatjes CA, Sheps L. Quantification of Key Peroxy and Hydroperoxide Intermediates in the Low-Temperature Oxidation of Dimethyl Ether. J Phys Chem A 2022; 126:9497-9509. [DOI: 10.1021/acs.jpca.2c06959] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- David E. Couch
- Combustion Research Facility, Sandia National Laboratories, Livermore, California94551, United States
| | - Clayton R. Mulvihill
- Chemical Sciences and Engineering, Argonne National Laboratory, Lemont, Illinois60439, United States
| | - Raghu Sivaramakrishnan
- Chemical Sciences and Engineering, Argonne National Laboratory, Lemont, Illinois60439, United States
| | - Kendrew Au
- Combustion Research Facility, Sandia National Laboratories, Livermore, California94551, United States
| | - Craig A. Taatjes
- Combustion Research Facility, Sandia National Laboratories, Livermore, California94551, United States
| | - Leonid Sheps
- Combustion Research Facility, Sandia National Laboratories, Livermore, California94551, United States
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8
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Popolan‐Vaida DM, Eskola AJ, Rotavera B, Lockyear JF, Wang Z, Sarathy SM, Caravan RL, Zádor J, Sheps L, Lucassen A, Moshammer K, Dagaut P, Osborn DL, Hansen N, Leone SR, Taatjes CA. Formation of Organic Acids and Carbonyl Compounds in
n
‐Butane Oxidation via γ‐Ketohydroperoxide Decomposition. Angew Chem Int Ed Engl 2022; 61:e202209168. [DOI: 10.1002/anie.202209168] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Indexed: 11/10/2022]
Affiliation(s)
- Denisia M. Popolan‐Vaida
- Department of Chemistry and Physics University of California, Berkeley Berkeley CA 94720 USA
- Department of Chemistry University of Central Florida Orlando FL 32816 USA
| | - Arkke J. Eskola
- Combustion Research Facility Sandia National Laboratories Livermore CA 94551 USA
- Department of Chemistry University of Helsinki 00014 Helsinki Finland
| | - Brandon Rotavera
- Combustion Research Facility Sandia National Laboratories Livermore CA 94551 USA
- Department of Chemistry and College of Engineering University of Georgia Athens GA 30602 USA
| | - Jessica F. Lockyear
- Department of Chemistry and Physics University of California, Berkeley Berkeley CA 94720 USA
| | - Zhandong Wang
- King Abdullah University of Science and Technology (KAUST) Clean Combustion Research Center (CCRC) Thuwal 23955-6900 Saudi Arabia
- National Synchrotron Radiation Laboratory University of Science and Technology of China Hefei Anhui 230029 P. R. China
| | - S. Mani Sarathy
- King Abdullah University of Science and Technology (KAUST) Clean Combustion Research Center (CCRC) Thuwal 23955-6900 Saudi Arabia
| | - Rebecca L. Caravan
- Combustion Research Facility Sandia National Laboratories Livermore CA 94551 USA
- Chemical Sciences and Engineering Division Argonne National Laboratory Lemont IL 60439 USA
| | - Judit Zádor
- Combustion Research Facility Sandia National Laboratories Livermore CA 94551 USA
| | - Leonid Sheps
- Combustion Research Facility Sandia National Laboratories Livermore CA 94551 USA
| | - Arnas Lucassen
- Combustion Research Facility Sandia National Laboratories Livermore CA 94551 USA
- Physikalisch-Technische Bundesanstalt 38116 Braunschweig Germany
| | - Kai Moshammer
- Combustion Research Facility Sandia National Laboratories Livermore CA 94551 USA
- Physikalisch-Technische Bundesanstalt 38116 Braunschweig Germany
| | - Philippe Dagaut
- Centre National de la Recherche Scientifique (CNRS) INSIS ICARE 45071 Orléans Cedex 2 France
| | - David L. Osborn
- Combustion Research Facility Sandia National Laboratories Livermore CA 94551 USA
| | - Nils Hansen
- Combustion Research Facility Sandia National Laboratories Livermore CA 94551 USA
| | - Stephen R. Leone
- Department of Chemistry and Physics University of California, Berkeley Berkeley CA 94720 USA
| | - Craig A. Taatjes
- Combustion Research Facility Sandia National Laboratories Livermore CA 94551 USA
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9
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Popolan-Vaida DM, Eskola AJ, Rotavera B, Lockyear JF, Wang Z, Sarathy SM, Caravan RL, Zádor J, Sheps L, Lucassen A, Moshammer K, Dagaut P, Osborn DL, Hansen N, Leone SR, Taatjes CA. Formation of Organic Acids and Carbonyl Compounds in n‐Butane Oxidation via γ‐Ketohydroperoxide Decomposition. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202209168] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
| | - Arkke J. Eskola
- University of Helsinki City Centre Campus: Helsingin Yliopisto Chemistry 00014 Helsinki FINLAND
| | | | - Jessica F. Lockyear
- University of California Berkeley College of Chemistry Chemistry 94720 Berkeley UNITED STATES
| | - Zhandong Wang
- University of Science and Technology of China Chemistry 230029 Hefei CHINA
| | - S. Mani Sarathy
- King Abdullah University of Science and Technology Clean Combustion Research Center 23955-6900 Thuwal SAUDI ARABIA
| | - Rebecca L. Caravan
- Argonne National Laboratory Chemical Sciences and Engineering Division 60439 Lemont UNITED STATES
| | - Judit Zádor
- Sandia National Laboratories California Combustion Research Facility 94551 Livermore UNITED STATES
| | - Leonid Sheps
- Sandia National Laboratories California Combustion Research Facility 94551 Livermore UNITED STATES
| | - Arnas Lucassen
- Physikalisch-Technische Bundesanstalt Prevention of Ignition Sources 38116 Braunschweig GERMANY
| | - Kai Moshammer
- Physikalisch-Technische Bundesanstalt Prevention of Ignition Sources 38116 Braunschweig GERMANY
| | - Philippe Dagaut
- Centre National de la Recherche Scientifique INSIS, ICARE 45071 Orléans Cedex FRANCE
| | - David L. Osborn
- Sandia National Laboratories California Combustion Research Facility 94551 Livermore UNITED STATES
| | - Nils Hansen
- Sandia National Laboratories California Combustion Research Facility 94551 Livermore UNITED STATES
| | - Stephen R. Leone
- University of California Berkeley College of Chemistry Chemistry 94720 Berkeley UNITED STATES
| | - Craig A. Taatjes
- Sandia National Laboratories California Combustion Research Facility 94551 Livermore UNITED STATES
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10
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Doner A, Zádor J, Rotavera B. Stereoisomer-dependent unimolecular kinetics of 2,4-dimethyloxetane peroxy radicals. Faraday Discuss 2022; 238:295-319. [DOI: 10.1039/d2fd00029f] [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
2,4,dimethyloxetane is an important cyclic ether intermediate that is produced from hydroperoxyalkyl (QOOH) radicals in low-temperature combustion of n-pentane. However, reaction mechanisms and rates of consumption pathways remain unclear. In...
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11
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Illés Á, Rózsa ZB, Thangaraj R, Décsiné Gombos E, Dóbé S, Giri BR, Szőri M. An experimental and theoretical kinetic study of the reactions of hydroxyl radicals with tetrahydrofuran and two deuterated tetrahydrofurans. Chem Phys Lett 2021. [DOI: 10.1016/j.cplett.2021.138698] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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12
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Sheps L, Dewyer AL, Demireva M, Zádor J. Quantitative Detection of Products and Radical Intermediates in Low-Temperature Oxidation of Cyclopentane. J Phys Chem A 2021; 125:4467-4479. [PMID: 34006098 DOI: 10.1021/acs.jpca.1c02001] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We present a combined experimental and theoretical investigation of the autoignition chemistry of a prototypical cyclic hydrocarbon, cyclopentane. Experiments using a high-pressure photolysis reactor coupled to time-resolved synchrotron VUV photoionization mass spectrometry directly probe the short-lived radical intermediates and products in cyclopentane oxidation reactions. We detect key peroxy radical intermediates ROO and OOQOOH, as well as several hydroperoxides, formed by second O2 addition. Automated quantum chemical calculations map out the R + O2 + O2 reaction channels and demonstrate that the detected intermediates belong to the dominant radical chain-branching pathway: ROO (+ O2) → γ-QOOH + O2 → γ-OOQOOH → products. ROO, OOQOOH, and hydroperoxide products of second-O2 addition undergo extensive dissociative ionization, making their experimental assignment challenging. We use photoionization dynamics calculations to aid in their characterization and report the absolute photoionization spectra of isomerically pure ROO and γ-OOQOOH. A global statistical fit of the observed kinetics enables reliable quantification of the time-resolved concentrations of these elusive, yet critical species, paving the way for detailed comparisons with theoretical predictions from master-equation-based models.
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Affiliation(s)
- Leonid Sheps
- Combustion Research Facility, Mail Stop 9055, Sandia National Laboratories, Livermore, California 94551-0969, United States
| | - Amanda L Dewyer
- Combustion Research Facility, Mail Stop 9055, Sandia National Laboratories, Livermore, California 94551-0969, United States
| | - Maria Demireva
- Combustion Research Facility, Mail Stop 9055, Sandia National Laboratories, Livermore, California 94551-0969, United States
| | - Judit Zádor
- Combustion Research Facility, Mail Stop 9055, Sandia National Laboratories, Livermore, California 94551-0969, United States
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13
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Demireva M, Au K, Sheps L. Direct time-resolved detection and quantification of key reactive intermediates in diethyl ether oxidation at T = 450-600 K. Phys Chem Chem Phys 2020; 22:24649-24661. [PMID: 33099590 DOI: 10.1039/d0cp03861j] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
High-pressure multiplexed photoionization mass spectrometry (MPIMS) with tunable vacuum ultraviolet (VUV) ionization radiation from the Lawrence Berkeley Labs Advanced Light Source is used to investigate the oxidation of diethyl ether (DEE). Kinetics and photoionization (PI) spectra are simultaneously measured for the species formed. Several stable products from DEE oxidation are identified and quantified using reference PI cross-sections. In addition, we directly detect and quantify three key chemical intermediates: peroxy (ROO˙), hydroperoxyalkyl peroxy (˙OOQOOH), and ketohydroperoxide (HOOP[double bond, length as m-dash]O, KHP). These intermediates undergo dissociative ionization (DI) into smaller fragments, making their identification by mass spectrometry challenging. With the aid of quantum chemical calculations, we identify the DI channels of these key chemical species and quantify their time-resolved concentrations from the overall carbon atom balance at T = 450 K and P = 7500 torr. This allows the determination of the absolute PI cross-sections of ROO˙, ˙OOQOOH, and KHP into each DI channel directly from experiment. The PI cross-sections in turn enable the quantification of ROO˙, ˙OOQOOH, and KHP from DEE oxidation over a range of experimental conditions that reveal the effects of pressure, O2 concentration, and temperature on the competition among radical decomposition and second O2 addition pathways.
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Affiliation(s)
- Maria Demireva
- Combustion Research Facility, Sandia National Laboratories, Livermore, California 94551, USA.
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14
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Li Y, Cao Z. Mechanisms and kinetics of the low-temperature oxidation of 2-methylfuran: insight from DFT calculations and kinetic simulations. Phys Chem Chem Phys 2020; 22:3290-3303. [PMID: 31970347 DOI: 10.1039/c9cp05937g] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The low-temperature oxidation (LTO) mechanisms of the 2-methylfuran (2-MF) biofuel and the corresponding thermodynamic and kinetic properties have been explored by density functional theory (DFT) and composite G4 methodologies as well as kinetic simulations. The O2 addition to the main furylCH2 radical from the methyl dehydrogenation in 2-MF forms three peroxide radicals PO1, PO2, and PO3 with the energy barriers of 15.1, 19.3, and 20.6 kcal mol-1 and the reaction ΔG of -8.2, 5.7, and -0.1 kcal mol-1 (298 K and 1 atm), respectively. Through hydrogen transfer followed by dehydroxylation, these nascent products evolve into stable aldehydes and cyclic ketones, which may further decompose into smaller species under the action of OH. Calculations and simulations show that the product P1 from the dehydroxylation of PO1 has a dominant population (higher than 96%) among the final products, although the temperature and pressure may influence the species profiles and rate constants to some extent. Based on the G4-calibrated thermodynamic parameters, the temperature and pressure dependence of the rate constants and the two- and three-parameter Arrhenius coefficients for all reactions considered here have been determined by using the transition state theory (TST) and Rice-Ramsperger-Kassel-Marcus (RRKM) methods. The present results provide a comprehensive understanding of the mechanisms and kinetics of the LTO process of the 2-MF biofuel.
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Affiliation(s)
- Yuanyuan Li
- State Key Laboratory of Physical Chemistry of Solid Surfaces and Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, China.
| | - Zexing Cao
- State Key Laboratory of Physical Chemistry of Solid Surfaces and Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, China.
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15
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Hansen N, Moshammer K, Jasper AW. Isomer-Selective Detection of Keto-Hydroperoxides in the Low-Temperature Oxidation of Tetrahydrofuran. J Phys Chem A 2019; 123:8274-8284. [PMID: 31483667 DOI: 10.1021/acs.jpca.9b07017] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Keto-hydroperoxides (KHPs) are reactive, partially oxidized intermediates that play a central role in chain-branching reactions during the gas-phase low-temperature oxidation of hydrocarbons and oxygenated species. Although multiple isomeric forms of the KHP intermediate are possible in complex oxidation environments when multiple reactant radicals exist that contain nonequivalent O2 addition sites, isomer-resolved data of KHPs have not been reported. In this work, we provide partially isomer-resolved detection and quantification of the KHPs that form during the low-temperature oxidation of tetrahydrofuran (THF, cycl.-O-CH2CH2CH2CH2-). We describe how these short-lived KHPs were detected, identified, and quantified using integrated experimental and theoretical approaches. The experimental approaches were based on direct molecular-beam sampling from a jet-stirred reactor operated at near-atmospheric pressure and at temperatures between 500 and 700 K, followed by mass spectrometry with single-photon ionization via tunable synchrotron-generated vacuum-ultraviolet radiation, and the identification of fragmentation patterns. The interpretation of the experiments was guided by theoretical calculations of ionization thresholds, fragment appearance energies, and photoionization cross sections. On the basis of the experimentally observed and theoretically calculated ionization and fragment appearance energies, KHP isomers could be distinguished as originating from H-abstraction reactions from either the α-C adjacent to the O atom or the β-C atoms. Temperature-dependent concentration profiles of the partially resolved isomeric KHP intermediates were determined in the range of 500-700 K, and the results indicate that the observed KHP isomers are formed overwhelmingly (∼99%) from the α-C THF radical. Comparisons of the partially isomer-resolved quantification of the KHPs to up-to-date kinetic modeling results reveal new opportunities for the development of a next-generation THF oxidation mechanism.
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Affiliation(s)
- Nils Hansen
- Combustion Research Facility , Sandia National Laboratories , Livermore , California 94551 , United States
| | - Kai Moshammer
- Physikalisch-Technische Bundesanstalt , Bundesallee 100 , 38116 Braunschweig , Germany
| | - Ahren W Jasper
- Chemical Sciences and Engineering Division , Argonne National Laboratory , Lemont , Illinois 60439 , United States
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16
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Davis JC, Koritzke AL, Caravan RL, Antonov IO, Christianson MG, Doner AC, Osborn DL, Sheps L, Taatjes CA, Rotavera B. Influence of the Ether Functional Group on Ketohydroperoxide Formation in Cyclic Hydrocarbons: Tetrahydropyran and Cyclohexane. J Phys Chem A 2019; 123:3634-3646. [PMID: 30865470 DOI: 10.1021/acs.jpca.8b12510] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Photolytically initiated oxidation experiments were conducted on cyclohexane and tetrahydropyran using multiplexed photoionization mass spectrometry to assess the impact of the ether functional group in the latter species on reaction mechanisms relevant to autoignition. Pseudo-first-order conditions, with [O2]0:[R•]0 > 2000, were used to ensure that R• + O2 → products were the dominant reactions. Quasi-continuous, tunable vacuum ultraviolet light from a synchrotron was employed over the range 8.0-11.0 eV to measure photoionization spectra of the products at two pressures (10 and 1520 Torr) and three temperatures (500, 600, and 700 K). Photoionization spectra of ketohydroperoxides were measured in both species and were qualitatively identical, within the limit of experimental noise, to those of analogous species formed in n-butane oxidation. However, differences were noted in the temperature dependence of ketohydroperoxide formation between the two species. Whereas the yield from cyclohexane is evident up to 700 K, ketohydroperoxides in tetrahydropyran were not detected above 650 K. The difference indicates that reaction mechanisms change due to the ether group, likely affecting the requisite •QOOH + O2 addition step. Branching fractions of nine species from tetrahydropyran were quantified with the objective of determining the role of ring-opening reactions in diminishing ketohydroperoxide. The results indicate that products formed from unimolecular decomposition of R• and •QOOH radicals via concerted C-C and C-O β-scission are pronounced in tetrahydropyran and are insignificant in cyclohexane oxidation. The main conclusion drawn is that, under the conditions herein, ring-opening pathways reduce the already low steady-state concentration of •QOOH, which in the case of tetrahydropyran prevents •QOOH + O2 reactions necessary for ketohydroperoxide formation. Carbon balance calculations reveal that products from ring opening of both R• and •QOOH, at 700 K, account for >70% at 10 Torr and >55% at 1520 Torr. Three pathways are confirmed to contribute to the depletion of •QOOH in tetrahydropyran including (i) γ-•QOOH → pentanedial + •OH, (ii) γ-•QOOH → vinyl formate + ethene + •OH, and (iii) γ-•QOOH → 3-butenal + formaldehyde + •OH. Analogous mechanisms in cyclohexane oxidation leading to similar intermediates are compared and, on the basis of mass spectral results, confirm that no such ring-opening reactions occur. The implication from the comparison to cyclohexane is that the ether group in tetrahydropyran increases the propensity for ring-opening reactions and inhibits the formation of ketohydroperoxide isomers that precede chain-branching. On the contrary, the absence of such reactions in cyclohexane enables ketohydroperoxide formation up to 700 K and perhaps higher temperature.
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Affiliation(s)
| | | | - Rebecca L Caravan
- Combustion Research Facility , Sandia National Laboratories , Livermore , California 94551 , United States
| | - Ivan O Antonov
- Combustion Research Facility , Sandia National Laboratories , Livermore , California 94551 , United States
| | | | | | - David L Osborn
- Combustion Research Facility , Sandia National Laboratories , Livermore , California 94551 , United States
| | - Leonid Sheps
- Combustion Research Facility , Sandia National Laboratories , Livermore , California 94551 , United States
| | - Craig A Taatjes
- Combustion Research Facility , Sandia National Laboratories , Livermore , California 94551 , United States
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17
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Tu Y, Wang JB, Li XY. Theoretical study of hydrogen abstraction by small radicals from cyclohexane-carbonyl-hydroperoxide. Theor Chem Acc 2019. [DOI: 10.1007/s00214-019-2426-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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18
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Telfah H, Reza MA, Alam J, Paul AC, Liu J. Direct Observation of Tetrahydrofuranyl and Tetrahydropyranyl Peroxy Radicals via Cavity Ring-Down Spectroscopy. J Phys Chem Lett 2018; 9:4475-4480. [PMID: 30037233 DOI: 10.1021/acs.jpclett.8b01721] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Room-temperature cavity ring-down (CRD) spectra of the à ← X̃ electronic transition of tetrahydrofuranyl peroxy (THFOO•) and tetrahydropyranyl peroxy (THPOO•) radicals were recorded. The peroxy radicals were produced by Cl-initiated oxidation of tetrahydrofuran and tetrahydropyran. Quantum chemical calculations of the lowest-energy conformers of all regioisomers of these two peroxy radicals have been carried out to aid the spectral simulation. Conformational identification and vibrational assignment were achieved by comparing the experimentally obtained spectra to the simulated ones. The absence of α-THPOO• absorption peaks in the CRD spectrum is attributed to ring opening due to its weak Cα'O bond.
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Affiliation(s)
- Hamzeh Telfah
- Department of Chemistry , University of Louisville , Louisville , Kentucky 40292 , United States
| | - Md Asmaul Reza
- Department of Chemistry , University of Louisville , Louisville , Kentucky 40292 , United States
| | - Jahangir Alam
- Department of Chemistry , University of Louisville , Louisville , Kentucky 40292 , United States
| | - Anam C Paul
- Department of Chemistry , University of Louisville , Louisville , Kentucky 40292 , United States
| | - Jinjun Liu
- Department of Chemistry , University of Louisville , Louisville , Kentucky 40292 , United States
- Conn Center for Renewable Energy Research , University of Louisville , Louisville , Kentucky 40292 , United States
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19
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Middaugh JE, Buras ZJ, Matrat M, Chu TC, Kim YS, Alecu IM, Vasiliou AK, Goldsmith CF, Green WH. A combined photoionization time-of-flight mass spectrometry and laser absorption spectrometry flash photolysis apparatus for simultaneous determination of reaction rates and product branching. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2018; 89:074102. [PMID: 30068092 DOI: 10.1063/1.5024399] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Accepted: 07/04/2018] [Indexed: 06/08/2023]
Abstract
In recent years, predictions of product branching for reactions of consequence to both combustion and atmospheric chemistry have outpaced validating experiments. An apparatus is described that aims to fill this void by combining several well-known experimental techniques into one: flash photolysis for radical generation, multiple-pass laser absorption spectrometry (LAS) for overall kinetics measurements, and time-resolved photoionization time-of-flight mass spectrometry (PI TOF-MS) for product branching quantification. The sensitivity of both the LAS and PI TOF-MS detection techniques is shown to be suitable for experiments with initial photolytically generated radical concentrations of ∼1 × 1012 molecules cm-3. As it is fast (μs time resolution) and non-intrusive, LAS is preferred for accurate kinetics (time-dependence) measurements. By contrast, PI TOF-MS is preferred for product quantification because it provides a near-complete picture of the reactor composition in a single mass spectrum. The value of simultaneous LAS and PI TOF-MS detection is demonstrated for the chemically interesting phenyl radical + propene system.
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Affiliation(s)
- Joshua E Middaugh
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Zachary J Buras
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Mickael Matrat
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Te-Chun Chu
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Young-Seok Kim
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Ionut M Alecu
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - AnGayle K Vasiliou
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - C Franklin Goldsmith
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - William H Green
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
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20
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Recent Trends in the Production, Combustion and Modeling of Furan-Based Fuels. ENERGIES 2018. [DOI: 10.3390/en11030512] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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21
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Eskola AJ, Antonov IO, Sheps L, Savee JD, Osborn DL, Taatjes CA. Time-resolved measurements of product formation in the low-temperature (550-675 K) oxidation of neopentane: a probe to investigate chain-branching mechanism. Phys Chem Chem Phys 2017; 19:13731-13745. [PMID: 28503692 DOI: 10.1039/c7cp01366c] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Product formation, in particular ketohydroperoxide formation and decomposition, were investigated in time-resolved, Cl-atom initiated neopentane oxidation experiments in the temperature range 550-675 K using a photoionization time-of-flight mass spectrometer. Ionization light was provided either by Advanced Light Source tunable synchrotron radiation or ∼10.2 eV fixed energy radiation from a H2-discharge lamp. Experiments were performed both at 1-2 atm pressure using a high-pressure reactor and also at ∼9 Torr pressure employing a low-pressure reactor for comparison. Because of the highly symmetric structure of neopentane, ketohydroperoxide signal can be attributed to a 3-hydroperoxy-2,2-dimethylpropanal isomer, i.e. from a γ-ketohydroperoxide (γ-KHP). The photoionization spectra of the γ-KHP measured at low- and high pressures and varying oxygen concentrations agree well with each other, further supporting they originate from the single isomer. Measurements performed in this work also suggest that the "Korcek" mechanism may play an important role in the decomposition of 3-hydroperoxy-2,2-dimethylpropanal, especially at lower temperatures. However, at higher temperatures where γ-KHP decomposition to hydroxyl radical and oxy-radical dominates, oxidation of the oxy-radical yields a new important channel leading to acetone, carbon monoxide, and OH radical. Starting from the initial neopentyl + O2 reaction, this channel releases altogether three OH radicals. A strongly temperature-dependent reaction product is observed at m/z = 100, likely attributable to 2,2-dimethylpropanedial.
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Affiliation(s)
- Arkke J Eskola
- Combustion Research Facility, Sandia National Laboratories, 7011 East Avenue, MS 9055, Livermore, California 94551, USA.
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