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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] [What about the content of this article? (0)] [Affiliation(s)] [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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2
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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3
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Zou M, Liu T, Vansco MF, Sojdak CA, Markus CR, Almeida R, Au K, Sheps L, Osborn DL, Winiberg FAF, Percival CJ, Taatjes CA, Klippenstein SJ, Lester MI, Caravan RL. Bimolecular Reaction of Methyl-Ethyl-Substituted Criegee Intermediate with SO 2. J Phys Chem A 2023; 127:8994-9002. [PMID: 37870411 DOI: 10.1021/acs.jpca.3c04648] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2023]
Abstract
Methyl-ethyl-substituted Criegee intermediate (MECI) is a four-carbon carbonyl oxide that is formed in the ozonolysis of some asymmetric alkenes. MECI is structurally similar to the isoprene-derived methyl vinyl ketone oxide (MVK-oxide) but lacks resonance stabilization, making it a promising candidate to help us unravel the effects of size, structure, and resonance stabilization that influence the reactivity of atmospherically important, highly functionalized Criegee intermediates. We present experimental and theoretical results from the first bimolecular study of MECI in its reaction with SO2, a reaction that shows significant sensitivity to the Criegee intermediate structure. Using multiplexed photoionization mass spectrometry, we obtain a rate coefficient of (1.3 ± 0.3) × 10-10 cm3 s-1 (95% confidence limits, 298 K, 10 Torr) and demonstrate the formation of SO3 under our experimental conditions. Through high-level theory, we explore the effect of Criegee intermediate structure on the minimum energy pathways for their reactions with SO2 and obtain modified Arrhenius fits to our predictions for the reaction of both syn and anti conformers of MECI with SO2 (ksyn = 4.42 × 1011 T-7.80exp(-1401/T) cm3 s-1 and kanti = 1.26 × 1011 T-7.55exp(-1397/T) cm3 s-1). Our experimental and theoretical rate coefficients (which are in reasonable agreement at 298 K) show that the reaction of MECI with SO2 is significantly faster than MVK-oxide + SO2, demonstrating the substantial effect of resonance stabilization on Criegee intermediate reactivity.
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Affiliation(s)
- Meijun Zou
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, United States
| | - Tianlin Liu
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, United States
| | - Michael F Vansco
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Christopher A Sojdak
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, United States
| | - Charles R Markus
- NASA Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, California 91109, United States
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States
| | - Raybel Almeida
- Combustion Research Facility, Mailstop 9055, Sandia National Laboratories, Livermore, California 94551, United States
| | - Kendrew Au
- Combustion Research Facility, Mailstop 9055, Sandia National Laboratories, Livermore, California 94551, United States
| | - Leonid Sheps
- Combustion Research Facility, Mailstop 9055, Sandia National Laboratories, Livermore, California 94551, United States
| | - David L Osborn
- Combustion Research Facility, Mailstop 9055, Sandia National Laboratories, Livermore, California 94551, United States
- Department of Chemical Engineering, University of California, Davis, California 95616, United States
| | - Frank A F Winiberg
- NASA Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, California 91109, United States
| | - Carl J Percival
- NASA Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, California 91109, United States
| | - Craig A Taatjes
- Combustion Research Facility, Mailstop 9055, Sandia National Laboratories, Livermore, California 94551, United States
| | - Stephen J Klippenstein
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Marsha I Lester
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, United States
| | - Rebecca L Caravan
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
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4
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Liu T, Elliott SN, Zou M, Vansco MF, Sojdak CA, Markus CR, Almeida R, Au K, Sheps L, Osborn DL, Winiberg FAF, Percival CJ, Taatjes CA, Caravan RL, Klippenstein SJ, Lester MI. OH Roaming and Beyond in the Unimolecular Decay of the Methyl-Ethyl-Substituted Criegee Intermediate: Observations and Predictions. J Am Chem Soc 2023; 145:19405-19420. [PMID: 37623926 DOI: 10.1021/jacs.3c07126] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/26/2023]
Abstract
Alkene ozonolysis generates short-lived Criegee intermediates that are a significant source of hydroxyl (OH) radicals. This study demonstrates that roaming of the separating OH radicals can yield alternate hydroxycarbonyl products, thereby reducing the OH yield. Specifically, hydroxybutanone has been detected as a stable product arising from roaming in the unimolecular decay of the methyl-ethyl-substituted Criegee intermediate (MECI) under thermal flow cell conditions. The dynamical features of this novel multistage dissociation plus a roaming unimolecular decay process have also been examined with ab initio kinetics calculations. Experimentally, hydroxybutanone isomers are distinguished from the isomeric MECI by their higher ionization threshold and distinctive photoionization spectra. Moreover, the exponential rise of the hydroxybutanone kinetic time profile matches that for the unimolecular decay of MECI. A weaker methyl vinyl ketone (MVK) photoionization signal is also attributed to OH roaming. Complementary multireference electronic structure calculations have been utilized to map the unimolecular decay pathways for MECI, starting with 1,4 H atom transfer from a methyl or methylene group to the terminal oxygen, followed by roaming of the separating OH and butanonyl radicals in the long-range region of the potential. Roaming via reorientation and the addition of OH to the vinyl group of butanonyl is shown to yield hydroxybutanone, and subsequent C-O elongation and H-transfer can lead to MVK. A comprehensive theoretical kinetic analysis has been conducted to evaluate rate constants and branching yields (ca. 10-11%) for thermal unimolecular decay of MECI to conventional and roaming products under laboratory and atmospheric conditions, consistent with the estimated experimental yield (ca. 7%).
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Affiliation(s)
- Tianlin Liu
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, United States
| | - Sarah N Elliott
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Meijun Zou
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, United States
| | - Michael F Vansco
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Christopher A Sojdak
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, United States
| | - Charles R Markus
- NASA Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, California 91109, United States
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States
| | - Raybel Almeida
- Combustion Research Facility, Mailstop 9055, Sandia National Laboratories, Livermore, California 94551, United States
| | - Kendrew Au
- Combustion Research Facility, Mailstop 9055, Sandia National Laboratories, Livermore, California 94551, United States
| | - Leonid Sheps
- Combustion Research Facility, Mailstop 9055, Sandia National Laboratories, Livermore, California 94551, United States
| | - David L Osborn
- Combustion Research Facility, Mailstop 9055, Sandia National Laboratories, Livermore, California 94551, United States
- Department of Chemical Engineering, University of California, Davis, California 95616, United States
| | - Frank A F Winiberg
- NASA Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, California 91109, United States
| | - Carl J Percival
- NASA Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, California 91109, United States
| | - Craig A Taatjes
- Combustion Research Facility, Mailstop 9055, Sandia National Laboratories, Livermore, California 94551, United States
| | - Rebecca L Caravan
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Stephen J Klippenstein
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Marsha I Lester
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, United States
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5
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Choudhary H, Das L, Pelton JG, Sheps L, Simmons BA, Gladden JM, Singh S. Funneled Depolymerization of Ionic Liquid-Based Biorefinery "Heterogeneous" Lignin into Guaiacols over Reusable Palladium Catalyst. Chemistry 2023; 29:e202300330. [PMID: 36746778 DOI: 10.1002/chem.202300330] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Accepted: 02/03/2023] [Indexed: 02/08/2023]
Abstract
The efficient utilization of lignin, the direct source of renewable aromatics, into value-added renewable chemicals is an important step towards sustainable biorefinery practices. Nevertheless, owing to the random heterogeneous structure and limited solubility, lignin utilization has been primarily limited to burning for energy. The catalytic depolymerization of lignin has been proposed and demonstrated as a viable route to sustainable biorefinery, however, low yields and poor selectivity of products, high char formation, and limited to no recycling of transition-metal-based catalyst involved in lignin depolymerization demands attention to enable practical-scale lignocellulosic biorefineries. In this study, we demonstrate the catalytic depolymerization of ionic liquid-based biorefinery poplar lignin into guaiacols over a reusable zirconium phosphate supported palladium catalyst. The essence of the study lies in the high conversion (>80 %), minimum char formation (7-16 %), high yields of guaiacols (up to 200 mg / g of lignin), and catalyst reusability. Both solid residue, liquid stream, and gaseous products were thoroughly characterized using ICP-OES, PXRD, CHN analysis, GC-MS, GPC, and 2D NMR to understand the hydrogenolysis pathway.
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Affiliation(s)
- Hemant Choudhary
- Deconstruction Division, Joint BioEnergy Institute, Emeryville, California, United States
- Department of Biomaterials and Biomanufacturing, Sandia National Laboratories, Livermore, California, United States
| | - Lalitendu Das
- Deconstruction Division, Joint BioEnergy Institute, Emeryville, California, United States
- Department of Biomaterials and Biomanufacturing, Sandia National Laboratories, Livermore, California, United States
| | - Jeffrey G Pelton
- QB3 Institute, University of California, Berkeley, Berkeley, California, United States
| | - Leonid Sheps
- Combustion Research Facility, Sandia National Laboratories, Livermore, California, United States
| | - Blake A Simmons
- Deconstruction Division, Joint BioEnergy Institute, Emeryville, California, United States
- Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, California, United States
| | - John M Gladden
- Deconstruction Division, Joint BioEnergy Institute, Emeryville, California, United States
- Department of Biomaterials and Biomanufacturing, Sandia National Laboratories, Livermore, California, United States
| | - Seema Singh
- Deconstruction Division, Joint BioEnergy Institute, Emeryville, California, United States
- Department of Biomaterials and Biomanufacturing, Sandia National Laboratories, Livermore, California, United States
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6
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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7
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Robinson C, Onel L, Newman J, Lade R, Au K, Sheps L, Heard DE, Seakins PW, Blitz MA, Stone D. Unimolecular Kinetics of Stabilized CH 3CHOO Criegee Intermediates: syn-CH 3CHOO Decomposition and anti-CH 3CHOO Isomerization. J Phys Chem A 2022; 126:6984-6994. [PMID: 36146923 PMCID: PMC9549458 DOI: 10.1021/acs.jpca.2c05461] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Revised: 09/11/2022] [Indexed: 11/30/2022]
Abstract
The kinetics of the unimolecular decomposition of the stabilized Criegee intermediate syn-CH3CHOO has been investigated at temperatures between 297 and 331 K and pressures between 12 and 300 Torr using laser flash photolysis of CH3CHI2/O2/N2 gas mixtures coupled with time-resolved broadband UV absorption spectroscopy. Fits to experimental results using the Master Equation Solver for Multi-Energy well Reactions (MESMER) indicate that the barrier height to decomposition is 67.2 ± 1.3 kJ mol-1 and that there is a strong tunneling component to the decomposition reaction under atmospheric conditions. At 298 K and 760 Torr, MESMER simulations indicate a rate coefficient of 150-81+176 s-1 when tunneling effects are included but only 5-2+3 s-1 when tunneling is not considered in the model. MESMER simulations were also performed for the unimolecular isomerization of the stabilized Criegee intermediate anti-CH3CHOO to methyldioxirane, indicating a rate coefficient of 54-21+34 s-1 at 298 K and 760 Torr, which is not impacted by tunneling effects. Expressions to describe the unimolecular kinetics of syn- and anti-CH3CHOO are provided for use in atmospheric models, and atmospheric implications are discussed.
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Affiliation(s)
- Callum Robinson
- School
of Chemistry, University of Leeds, Woodhouse Lane, Leeds LS2 9JT, U.K.
| | - Lavinia Onel
- School
of Chemistry, University of Leeds, Woodhouse Lane, Leeds LS2 9JT, U.K.
| | - James Newman
- School
of Chemistry, University of Leeds, Woodhouse Lane, Leeds LS2 9JT, U.K.
| | - Rachel Lade
- School
of Chemistry, University of Leeds, Woodhouse Lane, Leeds LS2 9JT, U.K.
| | - Kendrew Au
- Combustion
Research Facility, Sandia National Laboratories, Livermore, California 94551, United States
| | - Leonid Sheps
- Combustion
Research Facility, Sandia National Laboratories, Livermore, California 94551, United States
| | - Dwayne E. Heard
- School
of Chemistry, University of Leeds, Woodhouse Lane, Leeds LS2 9JT, U.K.
| | - Paul W. Seakins
- School
of Chemistry, University of Leeds, Woodhouse Lane, Leeds LS2 9JT, U.K.
| | - Mark A. Blitz
- School
of Chemistry, University of Leeds, Woodhouse Lane, Leeds LS2 9JT, U.K.
- National
Centre for Atmospheric Science, School of Chemistry, University of Leeds, Woodhouse Lane, Leeds LS2 9JT, U.K.
| | - Daniel Stone
- School
of Chemistry, University of Leeds, Woodhouse Lane, Leeds LS2 9JT, U.K.
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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] [What about the content of this article? (0)] [Affiliation(s)] [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] [What about the content of this article? (0)] [Affiliation(s)] [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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Taatjes CA, Caravan RL, Winiberg FAF, Zuraski K, Au K, Sheps L, Osborn DL, Vereecken L, Percival CJ. Insertion products in the reaction of carbonyl oxide Criegee intermediates with acids: Chloro(hydroperoxy)methane formation from reaction of CH2OO with HCl and DCl. Mol Phys 2021. [DOI: 10.1080/00268976.2021.1975199] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Affiliation(s)
- Craig A. Taatjes
- Combustion Research Facility, Mailstop 9055, Sandia National Laboratories, Livermore, CA, USA
| | - Rebecca L. Caravan
- Combustion Research Facility, Mailstop 9055, Sandia National Laboratories, Livermore, CA, USA
- NASA Postdoctoral Program Fellow, NASA Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, IL, USA
| | - Frank A. F. Winiberg
- NASA Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
- California Institute of Technology, Pasadena, CA, USA
| | - Kristen Zuraski
- NASA Postdoctoral Program Fellow, NASA Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
| | - Kendrew Au
- Combustion Research Facility, Mailstop 9055, Sandia National Laboratories, Livermore, CA, USA
| | - Leonid Sheps
- Combustion Research Facility, Mailstop 9055, Sandia National Laboratories, Livermore, CA, USA
| | - David L. Osborn
- Combustion Research Facility, Mailstop 9055, Sandia National Laboratories, Livermore, CA, USA
- Department of Chemical Engineering, University of California, Davis, CA, USA
| | - Luc Vereecken
- Institute of Energy and Climate Research, Forschungszentrum Jülich GmbH, Jülich, Germany
| | - Carl J. Percival
- NASA Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
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11
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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12
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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13
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Doner AC, Davis MM, Koritzke AL, Christianson MG, Turney JM, Schaefer HF, Sheps L, Osborn DL, Taatjes CA, Rotavera B. Isomer‐dependent reaction mechanisms of cyclic ether intermediates:cis‐2,3‐dimethyloxirane andtrans‐2,3‐dimethyloxirane. INT J CHEM KINET 2020. [DOI: 10.1002/kin.21429] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Anna C. Doner
- Department of Chemistry University of Georgia Athens GA USA
| | - Matthew M. Davis
- Department of Chemistry University of Georgia Athens GA USA
- Center for Computational Quantum Chemistry University of Georgia Athens GA USA
| | | | | | - Justin M. Turney
- Center for Computational Quantum Chemistry University of Georgia Athens GA USA
| | - Henry F. Schaefer
- Department of Chemistry University of Georgia Athens GA USA
- Center for Computational Quantum Chemistry University of Georgia Athens GA USA
| | - Leonid Sheps
- Combustion Research Facility Sandia National Laboratories Livermore CA USA
| | - David L. Osborn
- Combustion Research Facility Sandia National Laboratories Livermore CA USA
| | - Craig A. Taatjes
- Combustion Research Facility Sandia National Laboratories Livermore CA USA
| | - Brandon Rotavera
- Department of Chemistry University of Georgia Athens GA USA
- College of Engineering University of Georgia Athens GA USA
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14
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Christianson MG, Doner AC, Davis MM, Koritzke AL, Turney JM, Schaefer HF, Sheps L, Osborn DL, Taatjes CA, Rotavera B. Reaction mechanisms of a cyclic ether intermediate: Ethyloxirane. INT J CHEM KINET 2020. [DOI: 10.1002/kin.21423] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
| | - Anna C. Doner
- Department of Chemistry University of Georgia Athens Georgia
| | - Matthew M. Davis
- Department of Chemistry University of Georgia Athens Georgia
- Center for Computational Quantum Chemistry University of Georgia Athens Georgia
| | | | - Justin M. Turney
- Center for Computational Quantum Chemistry University of Georgia Athens Georgia
| | - Henry F. Schaefer
- Department of Chemistry University of Georgia Athens Georgia
- Center for Computational Quantum Chemistry University of Georgia Athens Georgia
| | - Leonid Sheps
- Combustion Research Facility Sandia National Laboratories Livermore California
| | - David L. Osborn
- Combustion Research Facility Sandia National Laboratories Livermore California
| | - Craig A. Taatjes
- Combustion Research Facility Sandia National Laboratories Livermore California
| | - Brandon Rotavera
- Department of Chemistry University of Georgia Athens Georgia
- College of Engineering University of Georgia Athens Georgia
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15
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Affiliation(s)
- Leonid Sheps
- Combustion Research Facility, Sandia National Laboratories, Livermore, California 94551, United States
| | - Ivan Antonov
- Combustion Research Facility, Sandia National Laboratories, Livermore, California 94551, United States
| | - Kendrew Au
- Combustion Research Facility, Sandia National Laboratories, Livermore, California 94551, United States
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16
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Antonov I, Voronova K, Chen MW, Sztáray B, Hemberger P, Bodi A, Osborn DL, Sheps L. To Boldly Look Where No One Has Looked Before: Identifying the Primary Photoproducts of Acetylacetone. J Phys Chem A 2019; 123:5472-5490. [DOI: 10.1021/acs.jpca.9b04640] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Affiliation(s)
- Ivan Antonov
- Combustion Research Facility, Sandia National Laboratories, Livermore, California 94551, United States
| | - Krisztina Voronova
- Department of Chemistry, University of the Pacific, Stockton, California 95211, United States
| | - Ming-Wei Chen
- Combustion Research Facility, Sandia National Laboratories, Livermore, California 94551, United States
| | - Bálint Sztáray
- Department of Chemistry, University of the Pacific, Stockton, California 95211, United States
| | | | - Andras Bodi
- Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland
| | - 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
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17
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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18
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Caravan RL, Khan MAH, Zádor J, Sheps L, Antonov IO, Rotavera B, Ramasesha K, Au K, Chen MW, Rösch D, Osborn DL, Fittschen C, Schoemaecker C, Duncianu M, Grira A, Dusanter S, Tomas A, Percival CJ, Shallcross DE, Taatjes CA. The reaction of hydroxyl and methylperoxy radicals is not a major source of atmospheric methanol. Nat Commun 2018; 9:4343. [PMID: 30341291 PMCID: PMC6195545 DOI: 10.1038/s41467-018-06716-x] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2018] [Accepted: 08/05/2018] [Indexed: 11/18/2022] Open
Abstract
Methanol is a benchmark for understanding tropospheric oxidation, but is underpredicted by up to 100% in atmospheric models. Recent work has suggested this discrepancy can be reconciled by the rapid reaction of hydroxyl and methylperoxy radicals with a methanol branching fraction of 30%. However, for fractions below 15%, methanol underprediction is exacerbated. Theoretical investigations of this reaction are challenging because of intersystem crossing between singlet and triplet surfaces - ∼45% of reaction products are obtained via intersystem crossing of a pre-product complex - which demands experimental determinations of product branching. Here we report direct measurements of methanol from this reaction. A branching fraction below 15% is established, consequently highlighting a large gap in the understanding of global methanol sources. These results support the recent high-level theoretical work and substantially reduce its uncertainties.
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Affiliation(s)
- Rebecca L Caravan
- Combustion Research Facility, Mailstop 9055, Sandia National Laboratories, Livermore, CA, 94551, USA.
| | - M Anwar H Khan
- School of Chemistry, Cantock's Close, University of Bristol, Bristol, BS8 1TS, UK
| | - Judit Zádor
- Combustion Research Facility, Mailstop 9055, Sandia National Laboratories, Livermore, CA, 94551, USA
| | - Leonid Sheps
- Combustion Research Facility, Mailstop 9055, Sandia National Laboratories, Livermore, CA, 94551, USA
| | - Ivan O Antonov
- Combustion Research Facility, Mailstop 9055, Sandia National Laboratories, Livermore, CA, 94551, USA
| | - Brandon Rotavera
- Combustion Research Facility, Mailstop 9055, Sandia National Laboratories, Livermore, CA, 94551, USA
| | - Krupa Ramasesha
- Combustion Research Facility, Mailstop 9055, Sandia National Laboratories, Livermore, CA, 94551, USA
| | - Kendrew Au
- Combustion Research Facility, Mailstop 9055, Sandia National Laboratories, Livermore, CA, 94551, USA
| | - Ming-Wei Chen
- Combustion Research Facility, Mailstop 9055, Sandia National Laboratories, Livermore, CA, 94551, USA
| | - Daniel Rösch
- Combustion Research Facility, Mailstop 9055, Sandia National Laboratories, Livermore, CA, 94551, USA
| | - David L Osborn
- Combustion Research Facility, Mailstop 9055, Sandia National Laboratories, Livermore, CA, 94551, USA
| | - Christa Fittschen
- Université Lille, CNRS, UMR 8522-PC2A-Physicochimie des Processus de Combustion et de l'Atmosphère, 59000, Lille, France
| | - Coralie Schoemaecker
- Université Lille, CNRS, UMR 8522-PC2A-Physicochimie des Processus de Combustion et de l'Atmosphère, 59000, Lille, France
| | - Marius Duncianu
- IMT Lille Douai, Université Lille, Département Sciences de l'Atmosphère et Génie de l'Environnement (SAGE), 59000, Lille, France
| | - Asma Grira
- IMT Lille Douai, Université Lille, Département Sciences de l'Atmosphère et Génie de l'Environnement (SAGE), 59000, Lille, France
| | - Sebastien Dusanter
- IMT Lille Douai, Université Lille, Département Sciences de l'Atmosphère et Génie de l'Environnement (SAGE), 59000, Lille, France
| | - Alexandre Tomas
- IMT Lille Douai, Université Lille, Département Sciences de l'Atmosphère et Génie de l'Environnement (SAGE), 59000, Lille, France
| | - Carl J Percival
- Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA, 91109, USA
| | - Dudley E Shallcross
- School of Chemistry, Cantock's Close, University of Bristol, Bristol, BS8 1TS, UK.
| | - Craig A Taatjes
- Combustion Research Facility, Mailstop 9055, Sandia National Laboratories, Livermore, CA, 94551, USA.
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19
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Stone D, Au K, Sime S, Medeiros DJ, Blitz M, Seakins PW, Decker Z, Sheps L. Unimolecular decomposition kinetics of the stabilised Criegee intermediates CH 2OO and CD 2OO. Phys Chem Chem Phys 2018; 20:24940-24954. [PMID: 30238099 DOI: 10.1039/c8cp05332d] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Decomposition kinetics of stabilised CH2OO and CD2OO Criegee intermediates have been investigated as a function of temperature (450-650 K) and pressure (2-350 Torr) using flash photolysis coupled with time-resolved cavity-enhanced broadband UV absorption spectroscopy. Decomposition of CD2OO was observed to be faster than CH2OO under equivalent conditions. Production of OH radicals following CH2OO decomposition was also monitored using flash photolysis with laser-induced fluorescence (LIF), with results indicating direct production of OH in the v = 0 and v = 1 states in low yields. Master equation calculations performed using the Master Equation Solver for Multi-Energy well Reactions (MESMER) enabled fitting of the barriers for the decomposition of CH2OO and CD2OO to the experimental data. Parameterisations of the decomposition rate coefficients, calculated by MESMER, are provided for use in atmospheric models and implications of the results are discussed. For CH2OO, the MESMER fits require an increase in the calculated barrier height from 78.2 kJ mol-1 to 81.8 kJ mol-1 using a temperature-dependent exponential down model for collisional energy transfer with ΔEdown = 32.6(T/298 K)1.7 cm-1 in He. The low- and high-pressure limit rate coefficients are k1,0 = 3.2 × 10-4(T/298)-5.81exp(-12 770/T) cm3 s-1 and k1,∞ = 1.4 × 1013(T/298)0.06exp(-10 010/T) s-1, with median uncertainty of ∼12% over the range of experimental conditions used here. Extrapolation to atmospheric conditions yields k1(298 K, 760 Torr) = 1.1+1.5-1.1 × 10-3 s-1. For CD2OO, MESMER calculations result in ΔEdown = 39.6(T/298 K)1.3 cm-1 in He and a small decrease in the calculated barrier to decomposition from 81.0 kJ mol-1 to 80.1 kJ mol-1. The fitted rate coefficients for CD2OO are k2,0 = 5.2 × 10-5(T/298)-5.28exp(-11 610/T) cm3 s-1 and k2,∞ = 1.2 × 1013(T/298)0.06exp(-9800/T) s-1, with overall error of ∼6% over the present range of temperature and pressure. The extrapolated k2(298 K, 760 Torr) = 5.5+9.2-5.5 × 10-3 s-1. The master equation calculations for CH2OO indicate decomposition yields of 63.7% for H2 + CO2, 36.0% for H2O + CO and 0.3% for OH + HCO with no significant dependence on temperature between 400 and 1200 K or pressure between 1 and 3000 Torr.
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Affiliation(s)
- Daniel Stone
- School of Chemistry, University of Leeds, Leeds, LS2 9JT, UK.
| | - Kendrew Au
- Combustion Research Facility, Sandia National Laboratories, Livermore, CA 94551, USA.
| | - Samantha Sime
- School of Chemistry, University of Leeds, Leeds, LS2 9JT, UK.
| | | | - Mark Blitz
- School of Chemistry, University of Leeds, Leeds, LS2 9JT, UK.
| | - Paul W Seakins
- School of Chemistry, University of Leeds, Leeds, LS2 9JT, UK.
| | - Zachary Decker
- Combustion Research Facility, Sandia National Laboratories, Livermore, CA 94551, USA.
| | - Leonid Sheps
- Combustion Research Facility, Sandia National Laboratories, Livermore, CA 94551, USA.
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20
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Sheps L, Rotavera B, Eskola AJ, Osborn DL, Taatjes CA, Au K, Shallcross DE, Khan MAH, Percival CJ. The reaction of Criegee intermediate CH 2OO with water dimer: primary products and atmospheric impact. Phys Chem Chem Phys 2018; 19:21970-21979. [PMID: 28805226 DOI: 10.1039/c7cp03265j] [Citation(s) in RCA: 62] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The rapid reaction of the smallest Criegee intermediate, CH2OO, with water dimers is the dominant removal mechanism for CH2OO in the Earth's atmosphere, but its products are not well understood. This reaction was recently suggested as a significant source of the most abundant tropospheric organic acid, formic acid (HCOOH), which is consistently underpredicted by atmospheric models. However, using time-resolved measurements of reaction kinetics by UV absorption and product analysis by photoionization mass spectrometry, we show that the primary products of this reaction are formaldehyde and hydroxymethyl hydroperoxide (HMHP), with direct HCOOH yields of less than 10%. Incorporating our results into a global chemistry-transport model further reduces HCOOH levels by 10-90%, relative to previous modeling assumptions, which indicates that the reaction CH2OO + water dimer by itself cannot resolve the discrepancy between the measured and predicted HCOOH levels.
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Affiliation(s)
- Leonid Sheps
- Combustion Research Facility, Sandia National Laboratories, 7011 East Ave., MS 9055, Livermore, California 94551, USA.
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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22
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Assaf E, Sheps L, Whalley L, Heard D, Tomas A, Schoemaecker C, Fittschen C. The Reaction between CH 3O 2 and OH Radicals: Product Yields and Atmospheric Implications. Environ Sci Technol 2017; 51:2170-2177. [PMID: 28121426 DOI: 10.1021/acs.est.6b06265] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
The reaction between CH3O2 and OH radicals has been shown to be fast and to play an appreciable role for the removal of CH3O2 radials in remote environments such as the marine boundary layer. Two different experimental techniques have been used here to determine the products of this reaction. The HO2 yield has been obtained from simultaneous time-resolved measurements of the absolute concentration of CH3O2, OH, and HO2 radicals by cw-CRDS. The possible formation of a Criegee intermediate has been measured by broadband cavity enhanced UV absorption. A yield of ϕHO2 = (0.8 ± 0.2) and an upper limit for ϕCriegee = 0.05 has been determined for this reaction, suggesting a minor yield of methanol or stabilized trioxide as a product. The impact of this reaction on the composition of the remote marine boundary layer has been determined by implementing these findings into a box model utilizing the Master Chemical Mechanism v3.2, and constraining the model for conditions found at the Cape Verde Atmospheric Observatory in the remote tropical Atlantic Ocean. Inclusion of the CH3O2+OH reaction into the model results in up to 30% decrease in the CH3O2 radical concentration while the HO2 concentration increased by up to 20%. Production and destruction of O3 are also influenced by these changes, and the model indicates that taking into account the reaction between CH3O2 and OH leads to a 6% decrease of O3.
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Affiliation(s)
- Emmanuel Assaf
- Université Lille, CNRS, UMR 8522 - PC2A - Physicochimie des Processus de Combustion et de l'Atmosphère, F-59000 Lille, France
| | - Leonid Sheps
- Combustion Research Facility, Sandia National Laboratories , 7011 East Ave., Livermore, California 94551 United States
| | - Lisa Whalley
- School of Chemistry, University of Leeds , Woodhouse Lane, Leeds, LS2 9JT, U.K
- National Centre for Atmospheric Chemistry, University of Leeds , Woodhouse Lane, Leeds, LS2 9JT, U.K
| | - Dwayne Heard
- School of Chemistry, University of Leeds , Woodhouse Lane, Leeds, LS2 9JT, U.K
- National Centre for Atmospheric Chemistry, University of Leeds , Woodhouse Lane, Leeds, LS2 9JT, U.K
| | - Alexandre Tomas
- IMT Lille Douai, Université Lille, SAGE - Département Sciences de l'Atmosphère et Génie de l'Environnement, 59000 Lille, France
| | - Coralie Schoemaecker
- Université Lille, CNRS, UMR 8522 - PC2A - Physicochimie des Processus de Combustion et de l'Atmosphère, F-59000 Lille, France
| | - Christa Fittschen
- Université Lille, CNRS, UMR 8522 - PC2A - Physicochimie des Processus de Combustion et de l'Atmosphère, F-59000 Lille, France
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23
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Decker ZCJ, Au K, Vereecken L, Sheps L. Direct experimental probing and theoretical analysis of the reaction between the simplest Criegee intermediate CH2OO and isoprene. Phys Chem Chem Phys 2017; 19:8541-8551. [DOI: 10.1039/c6cp08602k] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The reaction of CH2OO with isoprene, the highest-emitted unsaturated compound on Earth, is similar to reactions with small singly-unsaturated alkenes.
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Affiliation(s)
- Z. C. J. Decker
- Combustion Research Facility
- Sandia National Laboratories
- Livermore
- USA
| | - K. Au
- Combustion Research Facility
- Sandia National Laboratories
- Livermore
- USA
| | - L. Vereecken
- Institute for Energy and Climate Research
- Forschungszentrum Jülich GmbH
- 52428 Jülich
- Germany
| | - L. Sheps
- Combustion Research Facility
- Sandia National Laboratories
- Livermore
- USA
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24
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Scheer AM, Eskola AJ, Osborn DL, Sheps L, Taatjes CA. Resonance Stabilization Effects on Ketone Autoxidation: Isomer-Specific Cyclic Ether and Ketohydroperoxide Formation in the Low-Temperature (400–625 K) Oxidation of Diethyl Ketone. J Phys Chem A 2016; 120:8625-8636. [DOI: 10.1021/acs.jpca.6b07370] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Adam M. Scheer
- Combustion Research Facility, Sandia National Laboratories, MS 9055, Livermore, California 94551, United States
| | - Arkke J. Eskola
- Combustion Research Facility, Sandia National Laboratories, MS 9055, Livermore, California 94551, United States
| | - David L. Osborn
- Combustion Research Facility, Sandia National Laboratories, MS 9055, Livermore, California 94551, United States
| | - Leonid Sheps
- Combustion Research Facility, Sandia National Laboratories, MS 9055, Livermore, California 94551, United States
| | - Craig A. Taatjes
- Combustion Research Facility, Sandia National Laboratories, MS 9055, Livermore, California 94551, United States
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25
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Antonov IO, Zádor J, Rotavera B, Papajak E, Osborn DL, Taatjes CA, Sheps L. Pressure-Dependent Competition among Reaction Pathways from First- and Second-O2 Additions in the Low-Temperature Oxidation of Tetrahydrofuran. J Phys Chem A 2016; 120:6582-95. [DOI: 10.1021/acs.jpca.6b05411] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Ivan O. Antonov
- Combustion
Research Facility, Sandia National Laboratories, Livermore, California 94551, United States
| | - Judit Zádor
- Combustion
Research Facility, Sandia National Laboratories, Livermore, California 94551, United States
| | - Brandon Rotavera
- Combustion
Research Facility, Sandia National Laboratories, Livermore, California 94551, United States
| | - Ewa Papajak
- 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
| | - Craig A. Taatjes
- Combustion
Research Facility, Sandia National Laboratories, Livermore, California 94551, United States
| | - Leonid Sheps
- Combustion
Research Facility, Sandia National Laboratories, Livermore, California 94551, United States
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26
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Burke MP, Goldsmith CF, Klippenstein SJ, Welz O, Huang H, Antonov IO, Savee JD, Osborn DL, Zádor J, Taatjes CA, Sheps L. Multiscale Informatics for Low-Temperature Propane Oxidation: Further Complexities in Studies of Complex Reactions. J Phys Chem A 2015; 119:7095-115. [DOI: 10.1021/acs.jpca.5b01003] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Michael P. Burke
- Department of Mechanical Engineering, Department
of Chemical Engineering, and Data Sciences Institute, Columbia University, New York, New York, United States
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Argonne, Illinois, United States
| | - C. Franklin Goldsmith
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Argonne, Illinois, United States
- School of Engineering, Brown University, Providence, Rhode Island, United States
| | - Stephen J. Klippenstein
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Argonne, Illinois, United States
| | - Oliver Welz
- Combustion Research Facility, Sandia National Laboratories, Livermore, California, United States
| | - Haifeng Huang
- Combustion Research Facility, Sandia National Laboratories, Livermore, California, United States
| | - Ivan O. Antonov
- Combustion Research Facility, Sandia National Laboratories, Livermore, California, United States
| | - John D. Savee
- Combustion Research Facility, Sandia National Laboratories, Livermore, California, United States
| | - David L. Osborn
- Combustion Research Facility, Sandia National Laboratories, Livermore, California, United States
| | - Judit Zádor
- Combustion Research Facility, Sandia National Laboratories, Livermore, California, United States
| | - Craig A. Taatjes
- Combustion Research Facility, Sandia National Laboratories, Livermore, California, United States
| | - Leonid Sheps
- Combustion Research Facility, Sandia National Laboratories, Livermore, California, United States
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27
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Welz O, Burke MP, Antonov IO, Goldsmith CF, Savee JD, Osborn DL, Taatjes CA, Klippenstein SJ, Sheps L. New Insights into Low-Temperature Oxidation of Propane from Synchrotron Photoionization Mass Spectrometry and Multiscale Informatics Modeling. J Phys Chem A 2015; 119:7116-29. [DOI: 10.1021/acs.jpca.5b01008] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Oliver Welz
- Combustion
Research Facility, Sandia National Laboratories, Livermore, California 94551, United States
| | - Michael P. Burke
- Chemical
Sciences and Engineering Division, Argonne National Laboratory, Argonne, Illinois 60493, United States
- Department
of Mechanical Engineering, Department of Chemical Engineering and
Data Sciences Institute, Columbia University, New York, New York 10027, United States
| | - Ivan O. Antonov
- Combustion
Research Facility, Sandia National Laboratories, Livermore, California 94551, United States
| | - C. Franklin Goldsmith
- Chemical
Sciences and Engineering Division, Argonne National Laboratory, Argonne, Illinois 60493, United States
| | - John D. Savee
- 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
| | - Craig A. Taatjes
- Combustion
Research Facility, Sandia National Laboratories, Livermore, California 94551, United States
| | - Stephen J. Klippenstein
- Chemical
Sciences and Engineering Division, Argonne National Laboratory, Argonne, Illinois 60493, United States
| | - Leonid Sheps
- Combustion
Research Facility, Sandia National Laboratories, Livermore, California 94551, United States
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28
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Antonov IO, Kwok J, Zádor J, Sheps L. A Combined Experimental and Theoretical Study of the Reaction OH + 2-Butene in the 400–800 K Temperature Range. J Phys Chem A 2015; 119:7742-52. [DOI: 10.1021/acs.jpca.5b01012] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Ivan O. Antonov
- Combustion
Research Facility, Mail Stop 9055, Sandia National Laboratories, Livermore, California 94551-0969, United States
| | - Justin Kwok
- 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
| | - Leonid Sheps
- Combustion
Research Facility, Mail Stop 9055, Sandia National Laboratories, Livermore, California 94551-0969, United States
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29
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Savee JD, Papajak E, Rotavera B, Huang H, Eskola AJ, Welz O, Sheps L, Taatjes CA, Zádor J, Osborn DL. Direct observation and kinetics of a hydroperoxyalkyl radical (QOOH). Science 2015; 347:643-6. [DOI: 10.1126/science.aaa1495] [Citation(s) in RCA: 108] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Oxidation of organic compounds in combustion and in Earth’s troposphere is mediated by reactive species formed by the addition of molecular oxygen (O2) to organic radicals. Among the most crucial and elusive of these intermediates are hydroperoxyalkyl radicals, often denoted “QOOH.” These species and their reactions with O2 are responsible for the radical chain branching that sustains autoignition and are implicated in tropospheric autoxidation that can form low-volatility, highly oxygenated organic aerosol precursors. We report direct observation and kinetics measurements of a QOOH intermediate in the oxidation of 1,3-cycloheptadiene, a molecule that offers insight into both resonance-stabilized and nonstabilized radical intermediates. The results establish that resonance stabilization dramatically changes QOOH reactivity and, hence, that oxidation of unsaturated organics can produce exceptionally long-lived QOOH intermediates.
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30
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Rotavera B, Zádor J, Welz O, Sheps L, Scheer AM, Savee JD, Akbar Ali M, Lee TS, Simmons BA, Osborn DL, Violi A, Taatjes CA. Photoionization mass spectrometric measurements of initial reaction pathways in low-temperature oxidation of 2,5-dimethylhexane. J Phys Chem A 2014; 118:10188-200. [PMID: 25234586 DOI: 10.1021/jp507811d] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Product formation from R + O2 reactions relevant to low-temperature autoignition chemistry was studied for 2,5-dimethylhexane, a symmetrically branched octane isomer, at 550 and 650 K using Cl-atom initiated oxidation and multiplexed photoionization mass spectrometry (MPIMS). Interpretation of time- and photon-energy-resolved mass spectra led to three specific results important to characterizing the initial oxidation steps: (1) quantified isomer-resolved branching ratios for HO2 + alkene channels; (2) 2,2,5,5-tetramethyltetrahydrofuran is formed in substantial yield from addition of O2 to tertiary 2,5-dimethylhex-2-yl followed by isomerization of the resulting ROO adduct to tertiary hydroperoxyalkyl (QOOH) and exhibits a positive dependence on temperature over the range covered leading to a higher flux relative to aggregate cyclic ether yield. The higher relative flux is explained by a 1,5-hydrogen atom shift reaction that converts the initial primary alkyl radical (2,5-dimethylhex-1-yl) to the tertiary alkyl radical 2,5-dimethylhex-2-yl, providing an additional source of tertiary alkyl radicals. Quantum-chemical and master-equation calculations of the unimolecular decomposition of the primary alkyl radical reveal that isomerization to the tertiary alkyl radical is the most favorable pathway, and is favored over O2-addition at 650 K under the conditions herein. The isomerization pathway to tertiary alkyl radicals therefore contributes an additional mechanism to 2,2,5,5-tetramethyltetrahydrofuran formation; (3) carbonyl species (acetone, propanal, and methylpropanal) consistent with β-scission of QOOH radicals were formed in significant yield, indicating unimolecular QOOH decomposition into carbonyl + alkene + OH.
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Affiliation(s)
- Brandon Rotavera
- Combustion Chemistry Department, Combustion Research Facility, Sandia National Laboratories , Livermore, California 94550-0969, United States
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31
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Osborn DL, Vogelhuber KM, Wren SW, Miller EM, Lu YJ, Case AS, Sheps L, McMahon RJ, Stanton JF, Harding LB, Ruscic B, Lineberger WC. Electronic States of the Quasilinear Molecule Propargylene (HCCCH) from Negative Ion Photoelectron Spectroscopy. J Am Chem Soc 2014; 136:10361-72. [DOI: 10.1021/ja5039984] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Affiliation(s)
- David L. Osborn
- Combustion Research Facility, Sandia National Laboratories, Livermore, California 94551-0969, United States
- JILA
and Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309-0440, United States
| | - Kristen M. Vogelhuber
- JILA
and Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309-0440, United States
| | - Scott W. Wren
- JILA
and Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309-0440, United States
| | - Elisa M. Miller
- JILA
and Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309-0440, United States
| | - Yu-Ju Lu
- JILA
and Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309-0440, United States
| | - Amanda S. Case
- JILA
and Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309-0440, United States
| | - Leonid Sheps
- Combustion Research Facility, Sandia National Laboratories, Livermore, California 94551-0969, United States
| | - Robert J. McMahon
- Department
of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706-1322, United States
| | - John F. Stanton
- Institute
for Theoretical Chemistry, Department of Chemistry and Biochemistry, The University of Texas at Austin, Austin, Texas 78712, United States
| | - Lawrence B. Harding
- Division
of Chemical Sciences and Engineering, Argonne National Laboratory, Argonne, Illinois 60439, United States
| | - Branko Ruscic
- Division
of Chemical Sciences and Engineering, Argonne National Laboratory, Argonne, Illinois 60439, United States
| | - W. Carl Lineberger
- JILA
and Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309-0440, United States
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32
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Welz O, Eskola AJ, Sheps L, Rotavera B, Savee JD, Scheer AM, Osborn DL, Lowe D, Murray Booth A, Xiao P, Anwar H Khan M, Percival CJ, Shallcross DE, Taatjes CA. Rate coefficients of C(1) and C(2) Criegee intermediate reactions with formic and acetic Acid near the collision limit: direct kinetics measurements and atmospheric implications. Angew Chem Int Ed Engl 2014; 53:4547-50. [PMID: 24668781 PMCID: PMC4499262 DOI: 10.1002/anie.201400964] [Citation(s) in RCA: 147] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2014] [Indexed: 11/17/2022]
Abstract
Rate coefficients are directly determined for the reactions of the Criegee intermediates (CI) CH2OO and CH3CHOO with the two simplest carboxylic acids, formic acid (HCOOH) and acetic acid (CH3COOH), employing two complementary techniques: multiplexed photoionization mass spectrometry and cavity-enhanced broadband ultraviolet absorption spectroscopy. The measured rate coefficients are in excess of 1×10−10 cm3 s−1, several orders of magnitude larger than those suggested from many previous alkene ozonolysis experiments and assumed in atmospheric modeling studies. These results suggest that the reaction with carboxylic acids is a substantially more important loss process for CIs than is presently assumed. Implementing these rate coefficients in global atmospheric models shows that reactions between CI and organic acids make a substantial contribution to removal of these acids in terrestrial equatorial areas and in other regions where high CI concentrations occur such as high northern latitudes, and implies that sources of acids in these areas are larger than previously recognized.
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Affiliation(s)
- Oliver Welz
- Combustion Research Facility, Sandia National Laboratories, Stop 9055, Livermore, CA 94551-0969 (USA)
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33
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Welz O, Eskola AJ, Sheps L, Rotavera B, Savee JD, Scheer AM, Osborn DL, Lowe D, Murray Booth A, Xiao P, Anwar H. Khan M, Percival CJ, Shallcross DE, Taatjes CA. Rate Coefficients of C1 and C2 Criegee Intermediate Reactions with Formic and Acetic Acid Near the Collision Limit: Direct Kinetics Measurements and Atmospheric Implications. Angew Chem Int Ed Engl 2014. [DOI: 10.1002/ange.201400964] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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34
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Abstract
Transient absorption probing of a Criegee intermediate acetaldehyde oxide reveals the UV spectra of the two possible conformers, syn- and anti-CH3CHOO, and enables direct measurements of conformer-dependent reactivity.
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Affiliation(s)
- Leonid Sheps
- Combustion Research Facility MS 9055
- Sandia National Laboratories
- Livermore, USA
| | | | - Kendrew Au
- Combustion Research Facility MS 9055
- Sandia National Laboratories
- Livermore, USA
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35
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Abstract
We present the time-resolved UV absorption spectrum of the B̃ ((1)A') ← X̃ ((1)A') electronic transition of formaldehyde oxide, CH2OO, produced by the reaction of CH2I radicals with O2. In contrast to its UV photodissociation action spectrum, the absorption spectrum of formaldehyde oxide extends to longer wavelengths and exhibits resolved vibrational structure on its low-energy side. Chemical kinetics measurements of its reactivity establish the identity of the absorbing species as CH2OO. Separate measurements of the initial CH2I radical concentration allow a determination of the absolute absorption cross section of CH2OO, with the value at the peak of the absorption band, 355 nm, of σabs = (3.6 ± 0.9) × 10(-17) cm(2). The difference between the absorption and action spectra likely arises from excitation to long-lived B̃ ((1)A') vibrational states that relax to lower electronic states by fluorescence or nonradiative processes, rather than by photodissociation.
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Affiliation(s)
- Leonid Sheps
- Combustion Research Facility, Sandia National Laboratories, Mail Stop 9055, Livermore, California 94551-0969, United States
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36
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Welz O, Zádor J, Savee JD, Sheps L, Osborn DL, Taatjes CA. Low-Temperature Combustion Chemistry of n-Butanol: Principal Oxidation Pathways of Hydroxybutyl Radicals. J Phys Chem A 2013; 117:11983-2001. [DOI: 10.1021/jp403792t] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Oliver Welz
- Combustion
Research Facility, Mailstop 9055, Sandia National Laboratories, Livermore, California 94551-0969, United States
| | - Judit Zádor
- Combustion
Research Facility, Mailstop 9055, Sandia National Laboratories, Livermore, California 94551-0969, United States
| | - John D. Savee
- Combustion
Research Facility, Mailstop 9055, Sandia National Laboratories, Livermore, California 94551-0969, United States
| | - Leonid Sheps
- Combustion
Research Facility, Mailstop 9055, Sandia National Laboratories, Livermore, California 94551-0969, United States
| | - David L. Osborn
- Combustion
Research Facility, Mailstop 9055, Sandia National Laboratories, Livermore, California 94551-0969, United States
| | - Craig A. Taatjes
- Combustion
Research Facility, Mailstop 9055, Sandia National Laboratories, Livermore, California 94551-0969, United States
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37
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Wren SW, Vogelhuber KM, Garver JM, Kato S, Sheps L, Bierbaum VM, Lineberger WC. C–H Bond Strengths and Acidities in Aromatic Systems: Effects of Nitrogen Incorporation in Mono-, Di-, and Triazines. J Am Chem Soc 2012; 134:6584-95. [DOI: 10.1021/ja209566q] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Scott W. Wren
- JILA and Department of Chemistry and Biochemistry, University of Colorado, 440 UCB, Boulder, Colorado
80309, United States
| | - Kristen M. Vogelhuber
- JILA and Department of Chemistry and Biochemistry, University of Colorado, 440 UCB, Boulder, Colorado
80309, United States
| | - John M. Garver
- JILA and Department of Chemistry and Biochemistry, University of Colorado, 440 UCB, Boulder, Colorado
80309, United States
| | - Shuji Kato
- JILA and Department of Chemistry and Biochemistry, University of Colorado, 440 UCB, Boulder, Colorado
80309, United States
| | - Leonid Sheps
- JILA and Department of Chemistry and Biochemistry, University of Colorado, 440 UCB, Boulder, Colorado
80309, United States
| | - Veronica M. Bierbaum
- JILA and Department of Chemistry and Biochemistry, University of Colorado, 440 UCB, Boulder, Colorado
80309, United States
| | - W. Carl Lineberger
- JILA and Department of Chemistry and Biochemistry, University of Colorado, 440 UCB, Boulder, Colorado
80309, United States
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38
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Case AS, Miller EM, Martin JP, Lu YJ, Sheps L, McCoy AB, Lineberger WC. Dynamic Mapping of CN Rotation Following Photoexcitation of ICN−. Angew Chem Int Ed Engl 2012. [DOI: 10.1002/ange.201108025] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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39
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Welz O, Zádor J, Savee JD, Ng MY, Meloni G, Fernandes RX, Sheps L, Simmons BA, Lee TS, Osborn DL, Taatjes CA. Low-temperature combustion chemistry of biofuels: pathways in the initial low-temperature (550 K-750 K) oxidation chemistry of isopentanol. Phys Chem Chem Phys 2012; 14:3112-27. [PMID: 22286869 DOI: 10.1039/c2cp23248k] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The branched C(5) alcohol isopentanol (3-methylbutan-1-ol) has shown promise as a potential biofuel both because of new advanced biochemical routes for its production and because of its combustion characteristics, in particular as a fuel for homogeneous-charge compression ignition (HCCI) or related strategies. In the present work, the fundamental autoignition chemistry of isopentanol is investigated by using the technique of pulsed-photolytic Cl-initiated oxidation and by analyzing the reacting mixture by time-resolved tunable synchrotron photoionization mass spectrometry in low-pressure (8 Torr) experiments in the 550-750 K temperature range. The mass-spectrometric experiments reveal a rich chemistry for the initial steps of isopentanol oxidation and give new insight into the low-temperature oxidation mechanism of medium-chain alcohols. Formation of isopentanal (3-methylbutanal) and unsaturated alcohols (including enols) associated with HO(2) production was observed. Cyclic ether channels are not observed, although such channels dominate OH formation in alkane oxidation. Rather, products are observed that correspond to formation of OH viaβ-C-C bond fission pathways of QOOH species derived from β- and γ-hydroxyisopentylperoxy (RO(2)) radicals. In these pathways, internal hydrogen abstraction in the RO(2)⇄ QOOH isomerization reaction takes place from either the -OH group or the C-H bond in α-position to the -OH group. These pathways should be broadly characteristic for longer-chain alcohol oxidation. Isomer-resolved branching ratios are deduced, showing evolution of the main products from 550 to 750 K, which can be qualitatively explained by the dominance of RO(2) chemistry at lower temperature and hydroxyisopentyl decomposition at higher temperature.
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Affiliation(s)
- Oliver Welz
- Combustion Research Facility, Mail Stop 9055, Sandia National Laboratories, Livermore, California 94551-0969, USA.
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40
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Miller EM, Sheps L, Lu YJ, Case AS, McCoy AB, Lineberger WC. New view of the ICN A continuum using photoelectron spectroscopy of ICN-. J Chem Phys 2012; 136:044313. [PMID: 22299877 DOI: 10.1063/1.3679170] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Negative-ion photoelectron spectroscopy of ICN(-) (X̃ (2)Σ(+)) reveals transitions to the ground electronic state (X̃ (1)Σ(+)) of ICN as well as the first five excited states ((3)Π(2), (3)Π(1), Π(0(-) ) (3), Π(0(+) ) (3), and (1)Π(1)) that make up the ICN A continuum. By starting from the equilibrium geometry of the anion, photoelectron spectroscopy characterizes the electronic structure of ICN at an elongated I-C bond length of 2.65 Å. Because of this bond elongation, the lowest three excited states of ICN ((3)Π(2), (3)Π(1), and Π(0(-) ) (3)) are resolved for the first time in the photoelectron spectrum. In addition, the spectrum has a structured peak that arises from the frequently studied conical intersection between the Π(0(+) ) (3) and (1)Π(1) states. The assignment of the spectrum is aided by MR-SO-CISD calculations of the potential energy surfaces for the anion and neutral ICN electronic states, along with calculations of the vibrational levels supported by these states. Through thermochemical cycles involving spectrally narrow transitions to the excited states of ICN, we determine the electron affinity, EA(ICN), to be 1.34(5) (+0.04∕-0.02) eV and the anion dissociation energy, D(0)(X̃ (2)Σ(+) I-CN(-)), to be 0.83 (+0.04/-0.02) eV.
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Affiliation(s)
- Elisa M Miller
- JILA, Department of Chemistry and Biochemistry, University of Colorado at Boulder, Boulder, Colorado 80309, USA
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Vogelhuber KM, Wren SW, Sheps L, Lineberger WC. The C-H bond dissociation energy of furan: photoelectron spectroscopy of the furanide anion. J Chem Phys 2011; 134:064302. [PMID: 21322675 DOI: 10.1063/1.3548873] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Using photoelectron spectroscopy, we interrogate the cyclic furanide anion (C(4)H(3)O(-)) to determine the electron affinity and vibrational structure of the neutral furanyl radical and the term energy of its first excited electronic state. We present the 364-nm photoelectron spectrum of the furanide anion and measure the electron affinity of the X̃(2)A(') ground state of the α-furanyl radical to be 1.853(4) eV. A Franck-Condon analysis of the well-resolved spectrum allows determination of the harmonic frequencies of three of the most active vibrational modes upon X̃(2)A(') ← X̃(1)A(') photodetachment: 855(25), 1064(25), and 1307(40) cm(-1). These modes are ring deformation vibrations, consistent with the intuitive picture of furanide anion photodetachment, where the excess electron is strongly localized on the α-carbon atom. In addition, the Ã(2)A('') excited state of the α-furanyl radical is observed 0.68(7) eV higher in energy than the X̃(2)A(') ground state. Through a thermochemical cycle involving the known gas-phase acidity of furan, the electron affinity of the furanyl radical yields the first experimental determination of the C-H(α) bond dissociation energy of furan (DH(298)(C(4)H(3)O-H(α))): 119.8(2) kcal mol(-1).
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Affiliation(s)
- Kristen M Vogelhuber
- JILA and Department of Chemistry and Biochemistry, University of Colorado, 440 UCB, Boulder, Colorado 80309, USA
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Sheps L, Miller EM, Horvath S, Thompson MA, Parson R, McCoy AB, Lineberger WC. Solvent-mediated charge redistribution in photodissociation of IBr(-) and IBr(-)(CO2). J Chem Phys 2011; 134:184311. [PMID: 21568510 DOI: 10.1063/1.3584203] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
A combined experimental and theoretical investigation of photodissociation dynamics of IBr(-) and IBr(-)(CO(2)) on the B ((2)Σ(1/2)(+)) excited electronic state is presented. Time-resolved photoelectron spectroscopy reveals that in bare IBr(-) prompt dissociation forms exclusively I∗ + Br(-). Compared to earlier dissociation studies of IBr(-) excited to the A' ((2)Π(1∕2)) state, the signal rise is delayed by 200 ± 20 fs. In the case of IBr(-)(CO(2)), the product distribution shows the existence of a second major (∼40%) dissociation pathway, Br∗ + I(-). In contrast to the primary product channel, the signal rise associated with this pathway shows only a 50 ± 20 fs delay. The altered product branching ratio indicates that the presence of one solvent-like CO(2) molecule dramatically affects the electronic structure of the dissociating IBr(-). We explore the origins of this phenomenon with classical trajectories, quantum wave packet studies, and MR-SO-CISD calculations of the six lowest-energy electronic states of IBr(-) and 36 lowest-energy states of IBr. We find that the CO(2) molecule provides sufficient solvation energy to bring the initially excited state close in energy to a lower-lying state. The splitting between these states and the time at which the crossing takes place depend on the location of the solvating CO(2) molecule.
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Affiliation(s)
- Leonid Sheps
- JILA, Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309, USA
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Sheps L, Miller EM, Horvath S, Thompson MA, Parson R, McCoy AB, Lineberger WC. Solvent-Mediated Electron Hopping: Long-Range Charge Transfer in IBr
−
(CO
2
) Photodissociation. Science 2010; 328:220-4. [DOI: 10.1126/science.1184616] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Affiliation(s)
- Leonid Sheps
- JILA, Department of Chemistry and Biochemistry, University of Colorado at Boulder, Boulder, CO 80309, USA
| | - Elisa M. Miller
- JILA, Department of Chemistry and Biochemistry, University of Colorado at Boulder, Boulder, CO 80309, USA
| | - Samantha Horvath
- Department of Chemistry, The Ohio State University, Columbus, OH 43210, USA
| | - Matthew A. Thompson
- JILA, Department of Chemistry and Biochemistry, University of Colorado at Boulder, Boulder, CO 80309, USA
| | - Robert Parson
- JILA, Department of Chemistry and Biochemistry, University of Colorado at Boulder, Boulder, CO 80309, USA
| | - Anne B. McCoy
- Department of Chemistry, The Ohio State University, Columbus, OH 43210, USA
| | - W. Carl Lineberger
- JILA, Department of Chemistry and Biochemistry, University of Colorado at Boulder, Boulder, CO 80309, USA
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Sheps L, Miller EM, Lineberger WC. Photoelectron spectroscopy of small IBr[sup −](CO[sub 2])[sub n] (n=0–3) cluster anions. J Chem Phys 2009; 131:064304. [DOI: 10.1063/1.3200941] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Sheps L, Crowther AC, Carrier SL, Crim FF. Time-Resolved Spectroscopic Study of the Reaction Cl + n-C5H12 → HCl + C5H11 in Solution. J Phys Chem A 2005; 110:3087-92. [PMID: 16509630 DOI: 10.1021/jp0543835] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We study the hydrogen abstraction reaction from pentane by chlorine radicals using four different experimental approaches. We use two different solvents (CH2Cl2 and CCl4) and two different chlorine atom sources (photodissociation of dissolved Cl2 and two-photon photolysis of the solvent) to investigate their effects on the recombination and reactivity of the chlorine radical. All four experimental schemes involve direct probing of the transient chlorine population via a charge transfer transition with a solvent molecule. In one of the four approaches, photolysis of Cl2 in dichloromethane, we also monitor the nascent reaction products (HCl) by transient vibrational spectroscopy. Probing both the reactants and the products provides a comprehensive view of this bimolecular reaction in solution. Between one-third and two-thirds of the chlorine radicals that initially escape the solvent cage undergo diffusive geminate recombination with their partner radical (either another chlorine atom or the solvent radical). The rest react with pentane with the bimolecular rate constants k(bi) = (9.5 +/- 0.7) x 10(9) M(-1) s(-1) in CH2Cl2 and k(bi) = (7.4 +/- 2) x 10(9) M(-1) s(-1) in CCl4. The recombination yield phi(rec) depends on both the chlorine atom precursor and the solvent and is larger in the more viscous carbon tetrachloride solutions. The bimolecular reaction rate k(bi) depends only on the solvent and is consistent with a nearly diffusion-limited reaction.
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Affiliation(s)
- Leonid Sheps
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
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Sheps L, Crowther AC, Elles CG, Crim FF. Recombination Dynamics and Hydrogen Abstraction Reactions of Chlorine Radicals in Solution. J Phys Chem A 2005; 109:4296-302. [PMID: 16833759 DOI: 10.1021/jp051072l] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We observe chlorine radical dynamics in solution following two-photon photolysis of the solvent, dichloromethane. In neat CH(2)Cl(2), one-third of the chlorine radicals undergo diffusive geminate recombination, and the rest abstract a hydrogen atom from the solvent with a bimolecular rate constant of (1.35 +/- 0.06) x 10(7) M(-1) s(-1). Upon addition of hydrogen-containing solutes, the chlorine atom decay becomes faster, reflecting the presence of a new reaction pathway. We study 16 different solutes that include alkanes (pentane, hexane, heptane, and their cyclic analogues), alcohols (methanol, ethanol, 1-propanol, 2-propanol, and 1-butanol), and chlorinated alkanes (cyclohexyl chloride, 1-chlorobutane, 2-chlorobutane, 1,2-dichlorobutane, and 1,4-dichlorobutane). Chlorine reactions with alkanes have diffusion-limited rate constants that do not depend on the molecular structure, indicating the absence of a potential barrier. Hydrogen abstraction from alcohols is slower than from alkanes and depends weakly on molecular structure, consistent with a small reaction barrier. Reactions with chlorinated alkanes are the slowest, and their rate constants depend strongly on the number and position of the chlorine substituents, signaling the importance of activation barriers to these reactions. The relative rate constants for the activation-controlled reactions agree very well with the predictions of the gas-phase structure-activity relationships.
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Affiliation(s)
- Leonid Sheps
- Department of Chemistry, University of Wisconsin, Madison, WI 53706, USA
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Heckscher MM, Sheps L, Bingemann D, Crim FF. Relaxation of the C–H stretching fundamental vibrations of CHI3, CH2I2, and CH3I in solution. J Chem Phys 2002. [DOI: 10.1063/1.1510668] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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