1
|
Rodriguez R, Taatjes CA, Meloni G. Absolute Photoionization Cross Section and Dissociative Ionization Pathways of Alpha-Pinene. Chemphyschem 2024; 25:e202300891. [PMID: 38265929 DOI: 10.1002/cphc.202300891] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2023] [Revised: 01/12/2024] [Accepted: 01/22/2024] [Indexed: 01/26/2024]
Abstract
The absolute photoionization cross section of the monoterpenoid, alpha-pinene (AP), is presented together with the relative photoionization cross sections of its dissociative fragments for the first time. Experiments are performed via multiplexed vacuum ultraviolet (VUV) synchrotron photoionization (PI) mass spectrometry in the 8.0-11.0 eV energy range. Experimental work is conducted at the Advanced Light Source of the Lawrence Berkeley National Laboratory. Dissociative fragments were identified at m/z 121, 94, 93, 92, and 80. The photoionization cross section for the parent mass at 11.0 eV was determined to be 17±4 Mb with a total ionization cross section of 92±23 Mb at the same photon energy. Experimental appearance energies of dissociative ionization fragments and potential dissociative ionization pathways calculated at the G4 level of theory are presented as well.
Collapse
Affiliation(s)
- Ryan Rodriguez
- Department of Chemistry, University of San Francisco, San Francisco, CA 94117, USA
| | - Craig A Taatjes
- Combustion Research Facility, Sandia National Laboratories, Livermore, CA 94551, USA
| | - Giovanni Meloni
- Department of Chemistry, University of San Francisco, San Francisco, CA 94117, USA
- Department of Biological and Chemical Sciences, New York Institute of Technology, Old Westbury, NY 11568, USA
| |
Collapse
|
2
|
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] [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%).
Collapse
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
| |
Collapse
|
3
|
Doner AC, Dewey NS, Rotavera B. Unimolecular Reactions of 2-Methyloxetanyl and 2-Methyloxetanylperoxy Radicals. J Phys Chem A 2023; 127:6816-6829. [PMID: 37535464 PMCID: PMC10440797 DOI: 10.1021/acs.jpca.3c03918] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2023] [Revised: 07/17/2023] [Indexed: 08/05/2023]
Abstract
Alkyl-substituted cyclic ethers are intermediates formed in abundance during the low-temperature oxidation of hydrocarbons and biofuels via a chain-propagating step with ȮH. Subsequent reactions of cyclic ether radicals involve a competition between ring opening and reaction with O2, the latter of which enables pathways mediated by hydroperoxy-substituted carbon-centered radicals (Q̇OOH). Due to the resultant implications of competing unimolecular and bimolecular reactions on overall populations of ȮH, detailed insight into the chemical kinetics of cyclic ethers remains critical to high-fidelity numerical modeling of combustion. Cl-initiated oxidation experiments were conducted on 2-methyloxetane (an intermediate of n-butane oxidation) using multiplexed photoionization mass spectrometry (MPIMS), in tandem with calculations of stationary point energies on potential energy surfaces for unimolecular reactions of 2-methyloxetanyl and 2-methyloxetanylperoxy isomers. The potential energy surfaces were computed using the KinBot algorithm with stationary points calculated at the CCSD(T)-F12/cc-pVDZ-F12 level of theory. The experiments were conducted at 6 Torr and two temperatures (650 K and 800 K) under pseudo-first-order conditions to facilitate Ṙ + O2 reactions. Photoionization spectra were measured from 8.5 eV to 11.0 eV in 50-meV steps, and relative yields were quantified for species consistent with Ṙ → products and Q̇OOH → products. Species detected in the MPIMS experiments are linked to specific radicals of 2-methyloxetane. Species from Ṙ → products include methyl, ethene, formaldehyde, propene, ketene, 1,3-butadiene, and acrolein. Ion signals consistent with products from alkyl radical oxidation were detected, including for Q̇OOH-mediated species, which are also low-lying channels on their respective potential energy surfaces. In addition to species common to alkyl oxidation pathways, ring-opening reactions of Q̇OOH radicals derived from 2-methyloxetane produced ketohydroperoxide species (performic acid and 2-hydroperoxyacetaldehyde), which may impart additional chain-branching potential, and dicarbonyl species (3-oxobutanal and 2-methylpropanedial), which often serve as proxies for modeling reaction rates of ketohydroperoxides. The experimental and computational results underscore that reactions of cyclic ethers are inherently more complex than currently prescribed in chemical kinetic models utilized for combustion.
Collapse
Affiliation(s)
- Anna C. Doner
- University
of Georgia, Department of Chemistry, Athens, Georgia 30602, United States
| | - Nicholas S. Dewey
- University
of Georgia, Department of Chemistry, Athens, Georgia 30602, United States
| | - Brandon Rotavera
- University
of Georgia, Department of Chemistry, Athens, Georgia 30602, United States
- University
of Georgia, College of Engineering, Athens, Georgia 30602, United States
| |
Collapse
|
4
|
Zádor J, Martí C, Van de Vijver R, Johansen SL, Yang Y, Michelsen HA, Najm HN. Automated Reaction Kinetics of Gas-Phase Organic Species over Multiwell Potential Energy Surfaces. J Phys Chem A 2023; 127:565-588. [PMID: 36607817 DOI: 10.1021/acs.jpca.2c06558] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Automation of rate-coefficient calculations for gas-phase organic species became possible in recent years and has transformed how we explore these complicated systems computationally. Kinetics workflow tools bring rigor and speed and eliminate a large fraction of manual labor and related error sources. In this paper we give an overview of this quickly evolving field and illustrate, through five detailed examples, the capabilities of our own automated tool, KinBot. We bring examples from combustion and atmospheric chemistry of C-, H-, O-, and N-atom-containing species that are relevant to molecular weight growth and autoxidation processes. The examples shed light on the capabilities of automation and also highlight particular challenges associated with the various chemical systems that need to be addressed in future work.
Collapse
Affiliation(s)
- Judit Zádor
- Combustion Research Facility, Sandia National Laboratories, Livermore94550, California, United States
| | - Carles Martí
- Combustion Research Facility, Sandia National Laboratories, Livermore94550, California, United States
| | | | - Sommer L Johansen
- Combustion Research Facility, Sandia National Laboratories, Livermore94550, California, United States
| | - Yoona Yang
- Combustion Research Facility, Sandia National Laboratories, Livermore94550, California, United States
| | - Hope A Michelsen
- Department of Mechanical Engineering, University of Colorado Boulder, Boulder80309, Colorado, United States
| | - Habib N Najm
- Combustion Research Facility, Sandia National Laboratories, Livermore94550, California, United States
| |
Collapse
|
5
|
Li Y, Guan J, Wang H, Zhu L, Ye L, Wang Z. Predictive Combustion Kinetics of OH Radical Reactions with a C5 Unsaturated Alcohol: The Competitive H-Abstraction and OH-Addition Reactions of 2-Methyl-3-buten-2-ol. J Phys Chem A 2021; 125:10451-10462. [PMID: 34813343 DOI: 10.1021/acs.jpca.1c07623] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
2-Methyl-3-buten-2-ol (MBO232) is a potential biofuel and renewable fuel additive. In a combustion environment, the consumption of MBO232 is mainly through the reaction with a OH radical, one of the most important oxidants. Here, we predict the intricate reactions of MBO232 and OH radicals under a broad range of combustion conditions, that is, 230-2500 K and 0.01-1000 atm. The potential energy surfaces of H-abstraction and OH-addition have been investigated at the CCSD(T)/CBS//M06-2X/def2-TZVP level, and the rate constants were calculated via Rice-Ramsperger-Kassel-Marcus/master equation (RRKM/ME) theory. The decomposition reactions of the critical intermediates from the OH-addition reactions have also been studied. Our results show that OH-addition reactions are dominant below 850 K, while H-abstraction reactions, especially the channel-abstracting H atoms from the methyl groups, are more competitive at higher temperatures. We found that it is necessary to discriminate H atoms attached to the same C atom, as their abstraction rates can differ by up to 1 order of magnitude. The calculated results show good agreement with the reported experimental data. We have provided the modified Arrhenius expressions for rate constants of the dominant channels. The kinetic data determined in this work are of much value for constructing the combustion models of MBO232 and understanding the combustion kinetics and mechanism of other unsaturated alcohols.
Collapse
Affiliation(s)
- Yanbo Li
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, Anhui 230029, P. R. China
| | - Jiwen Guan
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, Anhui 230029, P. R. China
| | - Huanhuan Wang
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, Anhui 230029, P. R. China
| | - Long Zhu
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, Anhui 230029, P. R. China
| | - Lili Ye
- School of Chemical Engineering, Dalian University of Technology, Dalian, Liaoning 116024, P. R. China
| | - Zhandong Wang
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, Anhui 230029, P. R. China.,State Key Laboratory of Fire Science, University of Science and Technology of China, Hefei, Anhui 230026, P. R. China
| |
Collapse
|
6
|
Dai L, Lu Q, Zhou H, Shen F, Liu Z, Zhu W, Huang H. Tuning oxygenated functional groups on biochar for water pollution control: A critical review. JOURNAL OF HAZARDOUS MATERIALS 2021; 420:126547. [PMID: 34246863 DOI: 10.1016/j.jhazmat.2021.126547] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2021] [Revised: 06/28/2021] [Accepted: 06/28/2021] [Indexed: 06/13/2023]
Abstract
Biochar has attracted increasing attention in water pollution control, attributed to its various merits, e.g., tunable physico-chemical properties. The oxygenated functional groups (OFGs) on biochar are key active sites for removing pollutants from water through interfacial adsorption/redox reaction. However, there is still a lack of comprehensive knowledge and perspective on tuning OFGs on biochar for enhanced performance in water pollution control. Here, this review highlighted the mechanisms of biochar OFGs in water pollution control, analyzed the strategies and mechanisms for tuning OFGs on biochar, and investigated the performances of biochars with tuned OFGs in removing inorganic/organic pollutants via adsorption/redox reactions. Specifically, strategies for tuning OFGs on biochar are far more than the well-recognized ex-situ oxidation of pristine biochar. These strategies include in-situ low temperature preservation of hydroxyl and carboxyl, in-/ex-situ oxidation of biochar, and in-/ex-situ grafting of carboxyl on biochar via cycloaddition/acylation reaction. The resultant biochars showed enhanced performances in adsorption (mainly mediated by hydroxyl, carboxyl and ketone through surface complexation, H-bonding, and electrostatic attraction) and redox reaction (mainly mediated by redox-active hydroxyl and ketone). Finally, this review presented future directions on developing biochar with specially tuned surface OFGs as a sustainable high-performance adsorbent/carbocatalyst for water pollution control.
Collapse
Affiliation(s)
- Lichun Dai
- Key Laboratory of Development and Application of Rural Renewable Energy, Biogas Institute of Ministry of Agriculture and Rural Affairs, Chengdu 610041, China.
| | - Qian Lu
- Key Laboratory of Development and Application of Rural Renewable Energy, Biogas Institute of Ministry of Agriculture and Rural Affairs, Chengdu 610041, China
| | - Haiqin Zhou
- Key Laboratory of Development and Application of Rural Renewable Energy, Biogas Institute of Ministry of Agriculture and Rural Affairs, Chengdu 610041, China
| | - Fei Shen
- Institute of Ecological and Environmental Sciences, Sichuan Agricultural University, Chengdu 611130, China
| | - Zhengang Liu
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, 18 Shuangqing Road, Beijing 100085, China
| | - Wenkun Zhu
- State Key Laboratory of Environment-Friendly Energy Materials, National Co-Innovation Center for Nuclear Waste Disposal and Environmental Safety, Nuclear Waste and Environmental Safety Key Laboratory of Defense, School of National Defense Science & Technology, Southwest University of Science and Technology, Mianyang 621010, China.
| | - Huagang Huang
- College of Resources, Sichuan Agricultural University, Chengdu 611130, China
| |
Collapse
|
7
|
Giustini A, Aschi M, Park H, Meloni G. Theoretical and experimental study on the O( 3P) + 2,5-dimethylfuran reaction in the gas phase. Phys Chem Chem Phys 2021; 23:19424-19434. [PMID: 34296711 DOI: 10.1039/d1cp01724a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In this work we report a joint experimental and computational study on the 2,5-dimethylfuran oxidation reaction in the gas phase initiated by atomic oxygen O(3P). The experiments have been performed by using vacuum-ultraviolet synchrotron radiation at the Advanced Light Source (ALS) of the Lawrence Berkeley National Laboratory (LBNL), at a temperature of 550 K and a pressure of 8 Torr. The experimental data were supported by quantum-chemical calculations along with a kinetic model, also taking into account the possible involvement of different magnetic states, performed in the framework of the RRKM theory. Propyne, acetaldehyde, methylglyoxal, dimethylglyoxal, 3-penten-2-one, 2,5-dimethylfuran-3(2H)-one, and 1,2-diacetyl ethylene have been identified as the main primary products arising under the conditions of the experiment. Our computational model suggests that these species can be formed at the concentration and branching ratio experimentally observed only in the presence of a non-negligible fraction of non-thermalized intermediates.
Collapse
Affiliation(s)
- Andrea Giustini
- Dipartimento di Scienze Fisiche e Chimiche, Universita' degli Studi dell'Aquila, Via Vetoio, 67100 L'Aquila, Italy.
| | - Massimiliano Aschi
- Dipartimento di Scienze Fisiche e Chimiche, Universita' degli Studi dell'Aquila, Via Vetoio, 67100 L'Aquila, Italy.
| | - Heejune Park
- Department of Chemistry, University of San Francisco, 2130 Fulton St, San Francisco, 94117 California, USA.
| | - Giovanni Meloni
- Dipartimento di Scienze Fisiche e Chimiche, Universita' degli Studi dell'Aquila, Via Vetoio, 67100 L'Aquila, Italy. and Department of Chemistry, University of San Francisco, 2130 Fulton St, San Francisco, 94117 California, USA.
| |
Collapse
|
8
|
Study of the Synchrotron Photoionization Oxidation of Alpha-Angelica Lactone (AAL) Initiated by O( 3P) at 298, 550, and 700 K. Molecules 2021; 26:molecules26134070. [PMID: 34279410 PMCID: PMC8271512 DOI: 10.3390/molecules26134070] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2021] [Revised: 06/30/2021] [Accepted: 07/01/2021] [Indexed: 12/01/2022] Open
Abstract
In recent years, biofuels have been receiving significant attention because of their potential for decreasing carbon emissions and providing a long-term renewable solution to unsustainable fossil fuels. Currently, lactones are some of the alternatives being produced. Many lactones occur in a range of natural substances and have many advantages over bioethanol. In this study, the oxidation of alpha-angelica lactone initiated by ground-state atomic oxygen, O(3P), was studied at 298, 550, and 700 K using synchrotron radiation coupled with multiplexed photoionization mass spectrometry at the Lawrence Berkeley National Lab (LBNL). Photoionization spectra and kinetic time traces were measured to identify the primary products. Ketene, acetaldehyde, methyl vinyl ketone, methylglyoxal, dimethyl glyoxal, and 5-methyl-2,4-furandione were characterized as major reaction products, with ketene being the most abundant at all three temperatures. Possible reaction pathways for the formation of the observed primary products were computed using the CBS–QB3 composite method.
Collapse
|
9
|
Feng Y, Zhu J, Wang S, Yu L, He Z, Qian Y, Lu X. Theoretical and Experimental Study of 3-Pentanol Autoignition: Ab Initio Calculation, Shock Tube Experiments, and Kinetic Modeling. J Phys Chem A 2021; 125:5976-5989. [PMID: 34213330 DOI: 10.1021/acs.jpca.1c02713] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
3-Pentanol is a potential alternative fuel or a green fuel additive for modern engines. The H-abstraction reactions from 3-pentanol by H, CH3, HO2, and OH radicals are significant in the 3-pentanol oxidation process. However, corresponding rate constants are forced to rely on either analogy from sec-butanol or estimation from alkanes due to a lack of direct experimental and theoretical study. In this work, stationary points on the potential energy surfaces (PESs) were calculated with the high-level DLPNO-CCSD(T)/CBS(T-Q)//M06-2X/cc-pVTZ method, which is further used to benchmark against the CBS-QB3 method. Then, the high-pressure limit rate constants for target reactions, over a broad range of temperature (400-2000 K), were calculated with the phase-space theory and conventional transition state theory. A comparison was made between the calculated rate constants and the values available in Carbonnier et al. [ Proc. Combust. Inst. 2019, 37(1), 477-484]. The rate constants for the above H-abstraction reactions in the Carbonnier model were updated with the calculated results, followed by a modification based on the computed results of 3-pentanol + HO2 to obtain the revised model. Validation against the shock tube (ST) and the jet-stirred reactor (JSR) measurements from the literature proved the revised model an optimal one. Furthermore, using an ST, ignition delay times (IDTs) for the 3-pentanol/air mixtures were measured spanning a temperature range of 920-1450 K, pressures of 6, 10, and 20 bar, and equivalence ratios of 0.5, 1.0, and 1.5. Generally, IDTs decrease with increasing temperature and reflected shock pressure. Improved predictions to present experimental data were obtained by using the revised model as compared with the Carbonnier model. Finally, sensitivity analysis was conducted using the revised model to gain an in-depth comprehension of the 3-pentanol autoignition.
Collapse
Affiliation(s)
- Yuan Feng
- Key Laboratory for Power Machinery and Engineering of M. O. E, Shanghai Jiao Tong University, 200240 Shanghai, P. R. China
| | - Jizhen Zhu
- Key Laboratory for Power Machinery and Engineering of M. O. E, Shanghai Jiao Tong University, 200240 Shanghai, P. R. China
| | - Sixu Wang
- Key Laboratory for Power Machinery and Engineering of M. O. E, Shanghai Jiao Tong University, 200240 Shanghai, P. R. China
| | - Liang Yu
- Key Laboratory for Power Machinery and Engineering of M. O. E, Shanghai Jiao Tong University, 200240 Shanghai, P. R. China
| | - Zhuoyao He
- Key Laboratory for Power Machinery and Engineering of M. O. E, Shanghai Jiao Tong University, 200240 Shanghai, P. R. China
| | - Yong Qian
- Key Laboratory for Power Machinery and Engineering of M. O. E, Shanghai Jiao Tong University, 200240 Shanghai, P. R. China
| | - Xingcai Lu
- Key Laboratory for Power Machinery and Engineering of M. O. E, Shanghai Jiao Tong University, 200240 Shanghai, P. R. China
| |
Collapse
|
10
|
Elucidating the differences in oxidation of high-performance α- and β- diisobutylene biofuels via Synchrotron photoionization mass spectrometry. Sci Rep 2020; 10:21776. [PMID: 33311537 PMCID: PMC7733457 DOI: 10.1038/s41598-020-76462-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Accepted: 10/21/2020] [Indexed: 11/09/2022] Open
Abstract
Biofuels are a promising ecologically viable and renewable alternative to petroleum fuels, with the potential to reduce net greenhouse gas emissions. However, biomass sourced fuels are often produced as blends of hydrocarbons and their oxygenates. Such blending complicates the implementation of these fuels in combustion applications. Variations in a biofuel's composition will dictate combustion properties such as auto ignition temperature, reaction delay time, and reaction pathways. A handful of novel drop-in replacement biofuels for conventional transportation fuels have recently been down selected from a list of over 10,000 potential candidates as part of the U.S. Department of Energy's (DOE) Co-Optimization of Fuels and Engines (Co-Optima) initiative. Diisobutylene (DIB) is one such high-performing hydrocarbon which can readily be produced from the dehydration and dimerization of isobutanol, produced from the fermentation of biomass-derived sugars. The two most common isomers realized, from this process, are 2,4,4-trimethyl-1-pentene (α-DIB) and 2,4,4-trimethyl-2-pentene (β-DIB). Due to a difference in olefinic bond location, the α- and β- isomer exhibit dramatically different ignition temperatures at constant pressure and equivalence ratio. This may be attributed to different fragmentation pathways enabled by allylic versus vinylic carbons. For optimal implementation of these biofuel candidates, explicit identification of the intermediates formed during the combustion of each of the isomers is needed. To investigate the combustion pathways of these molecules, tunable vacuum ultraviolet (VUV) light (in the range 8.1-11.0 eV) available at the Lawrence Berkeley National Laboratory's Advanced Light Source (ALS) has been used in conjunction with a jet stirred reactor (JSR) and time-of-flight mass spectrometry to probe intermediates formed. Relative intensity curves for intermediate mass fragments produced during this process were obtained. Several important unique intermediates were identified at the lowest observable combustion temperature with static pressure of 93,325 Pa and for 1.5 s residence time. As this relatively short residence time is just after ignition, this study is targeted at the fuels' ignition events. Ignition characteristics for both isomers were found to be strongly dependent on the kinetics of C4 and C7 fragment production and decomposition, with the tert-butyl radical as a key intermediate species. However, the ignition of α-DIB exhibited larger concentrations of C4 compounds over C7, while the reverse was true for β-DIB. These identified species will allow for enhanced engineering modeling of fuel blending and engine design.
Collapse
|
11
|
Demireva M, Au K, Sheps L. Direct time-resolved detection and quantification of key reactive intermediates in diethyl ether oxidation at T = 450-600 K. Phys Chem Chem Phys 2020; 22:24649-24661. [PMID: 33099590 DOI: 10.1039/d0cp03861j] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
High-pressure multiplexed photoionization mass spectrometry (MPIMS) with tunable vacuum ultraviolet (VUV) ionization radiation from the Lawrence Berkeley Labs Advanced Light Source is used to investigate the oxidation of diethyl ether (DEE). Kinetics and photoionization (PI) spectra are simultaneously measured for the species formed. Several stable products from DEE oxidation are identified and quantified using reference PI cross-sections. In addition, we directly detect and quantify three key chemical intermediates: peroxy (ROO˙), hydroperoxyalkyl peroxy (˙OOQOOH), and ketohydroperoxide (HOOP[double bond, length as m-dash]O, KHP). These intermediates undergo dissociative ionization (DI) into smaller fragments, making their identification by mass spectrometry challenging. With the aid of quantum chemical calculations, we identify the DI channels of these key chemical species and quantify their time-resolved concentrations from the overall carbon atom balance at T = 450 K and P = 7500 torr. This allows the determination of the absolute PI cross-sections of ROO˙, ˙OOQOOH, and KHP into each DI channel directly from experiment. The PI cross-sections in turn enable the quantification of ROO˙, ˙OOQOOH, and KHP from DEE oxidation over a range of experimental conditions that reveal the effects of pressure, O2 concentration, and temperature on the competition among radical decomposition and second O2 addition pathways.
Collapse
Affiliation(s)
- Maria Demireva
- Combustion Research Facility, Sandia National Laboratories, Livermore, California 94551, USA.
| | | | | |
Collapse
|
12
|
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] [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
| |
Collapse
|
13
|
Kohse-Höinghaus K. Combustion in the future: The importance of chemistry. PROCEEDINGS OF THE COMBUSTION INSTITUTE. INTERNATIONAL SYMPOSIUM ON COMBUSTION 2020; 38:S1540-7489(20)30501-0. [PMID: 33013234 PMCID: PMC7518234 DOI: 10.1016/j.proci.2020.06.375] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/02/2019] [Revised: 05/18/2020] [Accepted: 06/28/2020] [Indexed: 06/11/2023]
Abstract
Combustion involves chemical reactions that are often highly exothermic. Combustion systems utilize the energy of chemical compounds released during this reactive process for transportation, to generate electric power, or to provide heat for various applications. Chemistry and combustion are interlinked in several ways. The outcome of a combustion process in terms of its energy and material balance, regarding the delivery of useful work as well as the generation of harmful emissions, depends sensitively on the molecular nature of the respective fuel. The design of efficient, low-emission combustion processes in compliance with air quality and climate goals suggests a closer inspection of the molecular properties and reactions of conventional, bio-derived, and synthetic fuels. Information about flammability, reaction intensity, and potentially hazardous combustion by-products is important also for safety considerations. Moreover, some of the compounds that serve as fuels can assume important roles in chemical energy storage and conversion. Combustion processes can furthermore be used to synthesize materials with attractive properties. A systematic understanding of the combustion behavior thus demands chemical knowledge. Desirable information includes properties of the thermodynamic states before and after the combustion reactions and relevant details about the dynamic processes that occur during the reactive transformations from the fuel and oxidizer to the products under the given boundary conditions. Combustion systems can be described, tailored, and improved by taking chemical knowledge into account. Combining theory, experiment, model development, simulation, and a systematic analysis of uncertainties enables qualitative or even quantitative predictions for many combustion situations of practical relevance. This article can highlight only a few of the numerous investigations on chemical processes for combustion and combustion-related science and applications, with a main focus on gas-phase reaction systems. It attempts to provide a snapshot of recent progress and a guide to exciting opportunities that drive such research beyond fossil combustion.
Collapse
Key Words
- 2M2B, 2-methyl-2-butene
- AFM, atomic force microscopy
- ALS, Advanced Light Source
- APCI, atmospheric pressure chemical ionization
- ARAS, atomic resonance absorption spectroscopy
- ATcT, Active Thermochemical Tables
- BC, black carbon
- BEV, battery electric vehicle
- BTL, biomass-to-liquid
- Biofuels
- CA, crank angle
- CCS, carbon capture and storage
- CEAS, cavity-enhanced absorption spectroscopy
- CFD, computational fluid dynamics
- CI, compression ignition
- CRDS, cavity ring-down spectroscopy
- CTL, coal-to-liquid
- Combustion
- Combustion chemistry
- Combustion diagnostics
- Combustion kinetics
- Combustion modeling
- Combustion synthesis
- DBE, di-n-butyl ether
- DCN, derived cetane number
- DEE, diethyl ether
- DFT, density functional theory
- DFWM, degenerate four-wave mixing
- DMC, dimethyl carbonate
- DME, dimethyl ether
- DMM, dimethoxy methane
- DRIFTS, diffuse reflectance infrared Fourier transform spectroscopy
- EGR, exhaust gas recirculation
- EI, electron ionization
- Emissions
- Energy
- Energy conversion
- FC, fuel cell
- FCEV, fuel cell electric vehicle
- FRET, fluorescence resonance energy transfer
- FT, Fischer-Tropsch
- FTIR, Fourier-transform infrared
- Fuels
- GC, gas chromatography
- GHG, greenhouse gas
- GTL, gas-to-liquid
- GW, global warming
- HAB, height above the burner
- HACA, hydrogen abstraction acetylene addition
- HCCI, homogeneous charge compression ignition
- HFO, heavy fuel oil
- HRTEM, high-resolution transmission electron microscopy
- IC, internal combustion
- ICEV, internal combustion engine vehicle
- IE, ionization energy
- IPCC, Intergovernmental Panel on Climate Change
- IR, infrared
- JSR, jet-stirred reactor
- KDE, kernel density estimation
- KHP, ketohydroperoxide
- LCA, lifecycle analysis
- LH2, liquid hydrogen
- LIF, laser-induced fluorescence
- LIGS, laser-induced grating spectroscopy
- LII, laser-induced incandescence
- LNG, liquefied natural gas
- LOHC, liquid organic hydrogen carrier
- LT, low-temperature
- LTC, low-temperature combustion
- MBMS, molecular-beam MS
- MDO, marine diesel oil
- MS, mass spectrometry
- MTO, methanol-to-olefins
- MVK, methyl vinyl ketone
- NOx, nitrogen oxides
- NTC, negative temperature coefficient
- OME, oxymethylene ether
- OTMS, Orbitrap MS
- PACT, predictive automated computational thermochemistry
- PAH, polycyclic aromatic hydrocarbon
- PDF, probability density function
- PEM, polymer electrolyte membrane
- PEPICO, photoelectron photoion coincidence
- PES, photoelectron spectrum/spectra
- PFR, plug-flow reactor
- PI, photoionization
- PIE, photoionization efficiency
- PIV, particle imaging velocimetry
- PLIF, planar laser-induced fluorescence
- PM, particulate matter
- PM10 PM2,5, sampled fractions with sizes up to ∼10 and ∼2,5 µm
- PRF, primary reference fuel
- QCL, quantum cascade laser
- RCCI, reactivity-controlled compression ignition
- RCM, rapid compression machine
- REMPI, resonance-enhanced multi-photon ionization
- RMG, reaction mechanism generator
- RON, research octane number
- Reaction mechanisms
- SI, spark ignition
- SIMS, secondary ion mass spectrometry
- SNG, synthetic natural gas
- SNR, signal-to-noise ratio
- SOA, secondary organic aerosol
- SOEC, solid-oxide electrolysis cell
- SOFC, solid-oxide fuel cell
- SOx, sulfur oxides
- STM, scanning tunneling microscopy
- SVO, straight vegetable oil
- Synthetic fuels
- TDLAS, tunable diode laser absorption spectroscopy
- TOF-MS, time-of-flight MS
- TPES, threshold photoelectron spectrum/spectra
- TPRF, toluene primary reference fuel
- TSI, threshold sooting index
- TiRe-LII, time-resolved LII
- UFP, ultrafine particle
- VOC, volatile organic compound
- VUV, vacuum ultraviolet
- WLTP, Worldwide Harmonized Light Vehicle Test Procedure
- XAS, X-ray absorption spectroscopy
- YSI, yield sooting index
Collapse
|
14
|
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] [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
| |
Collapse
|
15
|
Goldman MJ, Yee NW, Kroll JH, Green WH. Pressure-dependent kinetics of peroxy radicals formed in isobutanol combustion. Phys Chem Chem Phys 2020; 22:19802-19815. [PMID: 32844841 DOI: 10.1039/d0cp02872j] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Bio-derived isobutanol has been approved as a gasoline additive in the US, but our understanding of its combustion chemistry still has significant uncertainties. Detailed quantum calculations could improve model accuracy leading to better estimation of isobutanol's combustion properties and its environmental impacts. This work examines 47 molecules and 38 reactions involved in the first oxygen addition to isobutanol's three alkyl radicals located α, β, and γ to the hydroxide. Quantum calculations are mostly done at CCSD(T)-F12/cc-pVTZ-F12//B3LYP/CBSB7, with 1-D hindered rotor corrections obtained at B3LYP/6-31G(d). The resulting potential energy surfaces are the most comprehensive isobutanol peroxy networks published to date. Canonical transition state theory and a 1-D microcanonical master equation are used to derive high-pressure-limit and pressure-dependent rate coefficients, respectively. At all conditions studied, the recombination of γ-isobutanol radical with O2 forms HO2 + isobutanal. The recombination of β-isobutanol radical with O2 forms a stabilized hydroperoxy alkyl radical below 400 K, water + an alkoxy radical at higher temperatures, and HO2 + an alkene above 1200 K. The recombination of β-isobutanol radical with O2 results in a mixture of products between 700-1100 K, forming acetone + formaldehyde + OH at lower temperatures and forming HO2 + alkenes at higher temperatures. The barrier heights, high-pressure-limit rates, and pressure-dependent kinetics generally agree with the results from previous quantum chemistry calculations. Six reaction rates in this work deviate by over three orders of magnitude from kinetics in detailed models of isobutanol combustion, suggesting the rates calculated here can help improve modeling of isobutanol combustion and its environmental fate.
Collapse
Affiliation(s)
- Mark Jacob Goldman
- Department of Chemical Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue E17-504, Cambridge, MA 02139, USA.
| | | | | | | |
Collapse
|
16
|
Randazzo JB, Sivaramakrishnan R, Jasper AW, Sikes T, Lynch PT, Tranter RS. An experimental and theoretical study of the high temperature reactions of the four butyl radical isomers. Phys Chem Chem Phys 2020; 22:18304-18319. [PMID: 32785311 DOI: 10.1039/d0cp02404j] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The high temperature gas phase chemistry of the four butyl radical isomers (n-butyl, sec-butyl, iso-butyl, and tert-butyl) was investigated in a combined experimental and theoretical study. Organic nitrites were used as convenient and clean sources of each of the butyl radical isomers. Rate coefficients for dissociation of each nitrite were obtained experimentally and are at, or close to, the high pressure limit. Low pressure experiments were performed in a diaphragmless shock tube with laser schlieren densitometry at post-shock pressures of 65, 130, and 260 Torr and post-shock temperatures of 700-1000 K. Additional experiments were conducted with iso-butyl radicals at 805 K and 8.7 bar to elucidate changes in mechanism at higher pressures. These experiments were performed in a miniature shock tube with synchrotron-based photoionization mass spectrometry. The mass spectra confirmed that scission of the O-NO bond is the primary channel by which the precursors dissociate, but they also provided evidence of a minor channel (<7.7%) through HNO loss and formation of an aldehyde. These high pressure experiments were also used to determine the disproportionation/recombination ratio for iso-butyl radicals as 0.3. Reanalysis of the lower-temperature literature and the present data yielded rate constants for the disproportionation reaction, iso-butyl + iso-butyl = iso-butene + iso-butane. A chemical kinetics model was developed for the reactions of the butyl isomers that included new paths for highly energized adducts. These adducts are formed by the addition of H, CH3 or C2H5 to the butyl radicals. Accompanying theoretical investigations show that chemically activated pathways are competitive with stabilization of the adduct by collision under the conditions of the laser schlieren experiments. These calculations also show that at 10 bar and T < 1000 K stabilization is the only important reaction, but at higher temperatures, even at 10 bar, chemically activated product channels should also be considered. Branching fractions and rate coefficients are presented for these reactions. This study also highlights the importance of the radical structure for determining branching ratios for disproportionation and recombination of alkyl radicals, and these were facilitated by theoretical calculations of recombination rate coefficients for the four butyl radical isomers. The results reveal previously unknown features of butyl radical chemistry under conditions that are relevant to a wide range of applications and reaction mechanisms are presented that incorporate pressure dependent rate coefficients for the key steps.
Collapse
Affiliation(s)
- John B Randazzo
- Chemical Sciences and Engineering Division, Argonne National Laboratory, 9700 S. Cass Avenue, Lemont, IL 60439, USA.
| | | | | | | | | | | |
Collapse
|
17
|
Effect of the Ala234Asp replacement in mitochondrial branched-chain amino acid aminotransferase on the production of BCAAs and fusel alcohols in yeast. Appl Microbiol Biotechnol 2020; 104:7915-7925. [PMID: 32776205 DOI: 10.1007/s00253-020-10800-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Revised: 07/17/2020] [Accepted: 07/27/2020] [Indexed: 12/22/2022]
Abstract
In the yeast Saccharomyces cerevisiae, the mitochondrial branched-chain amino acid (BCAA) aminotransferase Bat1 plays an important role in the synthesis of BCAAs (valine, leucine, and isoleucine). Our upcoming study (Large et al. bioRχiv. 10.1101/2020.06.26.166157, Large et al. 2020) will show that the heterozygous tetraploid beer yeast strain, Wyeast 1056, which natively has a variant causing one amino acid substitution of Ala234Asp in Bat1 on one of the four chromosomes, produced higher levels of BCAA-derived fusel alcohols in the brewer's wort medium than a derived strain lacking this mutation. Here, we investigated the physiological role of the A234D variant Bat1 in S. cerevisiae. Both bat1∆ and bat1A234D cells exhibited the same phenotypes relative to the wild-type Bat1 strain-namely, a repressive growth rate in the logarithmic phase; decreases in intracellular valine and leucine content in the logarithmic and stationary growth phases, respectively; an increase in fusel alcohol content in culture medium; and a decrease in the carbon dioxide productivity. These results indicate that amino acid change from Ala to Asp at position 234 led to a functional impairment of Bat1, although homology modeling suggests that Asp234 in the variant Bat1 did not inhibit enzymatic activity directly. KEY POINTS: • Yeast cells expressing Bat1A234D exhibited a slower growth phenotype. • The Val and Leu levels were decreased in yeast cells expressing Bat1A234D. • The A234D substitution causes a loss-of-function in Bat1. • The A234D substitution in Bat1 increased fusel alcohol production in yeast cells.
Collapse
|
18
|
Li Y, Zhao Q, Zhang Y, Huang Z, Sarathy SM. A Systematic Theoretical Kinetics Analysis for the Waddington Mechanism in the Low-Temperature Oxidation of Butene and Butanol Isomers. J Phys Chem A 2020; 124:5646-5656. [PMID: 32574048 PMCID: PMC7467721 DOI: 10.1021/acs.jpca.0c03515] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
![]()
The
Waddington mechanism, or the Waddington-type reaction pathway,
is crucial for low-temperature oxidation of both alkenes and alcohols.
In this study, the Waddington mechanism in the oxidation chemistry
of butene and butanol isomers was systematically investigated. Fundamental
quantum chemical calculations were conducted for the rate constants
and thermodynamic properties of the reactions and species in this
mechanism. Calculations were performed using two different ab initio solvers: Gaussian 09 and Orca 4.0.0, and two different
kinetic solvers: PAPR and MultiWell, comprehensively. Temperature-
and pressure-dependent rate constants were performed based on the
transition state theory, associated with the Rice Ramsperger Kassel
Marcus and master equation theories. Temperature-dependent thermochemistry
(enthalpies of formation, entropy, and heat capacity) of all major
species was also conducted, based on the statistical thermodynamics.
Of the two types of reaction, dissociation reactions were significantly
faster than isomerization reactions, while the rate constants of both
reactions converged toward higher temperatures. In comparison, between
two ab initio solvers, the barrier height difference
among all isomerization and dissociation reactions was about 2 and
0.5 kcal/mol, respectively, resulting in less than 50%, and a factor
of 2–10 differences for the predicted rate coefficients of
the two reaction types, respectively. Comparing the two kinetic solvers,
the rate constants of the isomerization reactions showed less than
a 32% difference, while the rate of one dissociation reaction (P1
↔ WDT12) exhibited 1–2 orders of magnitude discrepancy.
Compared with results from the literature, both reaction rate coefficients
(R4 and R5 reaction systems) and species’ thermochemistry (all
closed shell molecules and open shell radicals R4 and R5) showed good
agreement with the corresponding values obtained from the literature.
All calculated results can be directly used for the chemical kinetic
model development of butene and butanol isomer oxidation.
Collapse
Affiliation(s)
- Yang Li
- King Abdullah University of Science and Technology, Clean Combustion Research Centre, Thuwal 23955, Saudi Arabia
| | - Qian Zhao
- State Key Laboratory of Multiphase Flows in Power Engineering, Xi'an Jiaotong University, Xi'an 710049, People's Republic of China
| | - Yingjia Zhang
- State Key Laboratory of Multiphase Flows in Power Engineering, Xi'an Jiaotong University, Xi'an 710049, People's Republic of China
| | - Zuohua Huang
- State Key Laboratory of Multiphase Flows in Power Engineering, Xi'an Jiaotong University, Xi'an 710049, People's Republic of China
| | - S Mani Sarathy
- King Abdullah University of Science and Technology, Clean Combustion Research Centre, Thuwal 23955, Saudi Arabia
| |
Collapse
|
19
|
Vansco MF, Caravan RL, Zuraski K, Winiberg FAF, Au K, Trongsiriwat N, Walsh PJ, Osborn DL, Percival CJ, Khan MAH, Shallcross DE, Taatjes CA, Lester MI. Experimental Evidence of Dioxole Unimolecular Decay Pathway for Isoprene-Derived Criegee Intermediates. J Phys Chem A 2020; 124:3542-3554. [PMID: 32255634 DOI: 10.1021/acs.jpca.0c02138] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Ozonolysis of isoprene, one of the most abundant volatile organic compounds emitted into the Earth's atmosphere, generates two four-carbon unsaturated Criegee intermediates, methyl vinyl ketone oxide (MVK-oxide) and methacrolein oxide (MACR-oxide). The extended conjugation between the vinyl substituent and carbonyl oxide groups of these Criegee intermediates facilitates rapid electrocyclic ring closures that form five-membered cyclic peroxides, known as dioxoles. This study reports the first experimental evidence of this novel decay pathway, which is predicted to be the dominant atmospheric sink for specific conformational forms of MVK-oxide (anti) and MACR-oxide (syn) with the vinyl substituent adjacent to the terminal O atom. The resulting dioxoles are predicted to undergo rapid unimolecular decay to oxygenated hydrocarbon radical products, including acetyl, vinoxy, formyl, and 2-methylvinoxy radicals. In the presence of O2, these radicals rapidly react to form peroxy radicals (ROO), which quickly decay via carbon-centered radical intermediates (QOOH) to stable carbonyl products that were identified in this work. The carbonyl products were detected under thermal conditions (298 K, 10 Torr He) using multiplexed photoionization mass spectrometry (MPIMS). The main products (and associated relative abundances) originating from unimolecular decay of anti-MVK-oxide and subsequent reaction with O2 are formaldehyde (88 ± 5%), ketene (9 ± 1%), and glyoxal (3 ± 1%). Those identified from the unimolecular decay of syn-MACR-oxide and subsequent reaction with O2 are acetaldehyde (37 ± 7%), vinyl alcohol (9 ± 1%), methylketene (2 ± 1%), and acrolein (52 ± 5%). In addition to the stable carbonyl products, the secondary peroxy chemistry also generates OH or HO2 radical coproducts.
Collapse
Affiliation(s)
- Michael F Vansco
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, United States
| | - Rebecca L Caravan
- NASA Postdoctoral Program, NASA Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, California 91109, United States.,Combustion Research Facility, Sandia National Laboratories, Mailstop 9055, Livermore, California 94551, United States.,Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Kristen Zuraski
- NASA Postdoctoral Program, NASA Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, California 91109, United States
| | - Frank A F Winiberg
- NASA Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, California 91109, United States.,California Institute of Technology, Pasadena, California 91125, United States
| | - Kendrew Au
- Combustion Research Facility, Sandia National Laboratories, Mailstop 9055, Livermore, California 94551, United States
| | - Nisalak Trongsiriwat
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, United States
| | - Patrick J Walsh
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, United States
| | - David L Osborn
- Combustion Research Facility, Sandia National Laboratories, Mailstop 9055, Livermore, California 94551, United States
| | - Carl J Percival
- NASA Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, California 91109, United States.,California Institute of Technology, Pasadena, California 91125, United States
| | - M Anwar H Khan
- School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, U.K
| | - Dudley E Shallcross
- School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, U.K
| | - Craig A Taatjes
- Combustion Research Facility, Sandia National Laboratories, Mailstop 9055, Livermore, California 94551, United States
| | - Marsha I Lester
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, United States
| |
Collapse
|
20
|
Giustini A, Meloni G. Synchrotron Photoionization Study of the Diisopropyl Ether Oxidation. Chemphyschem 2020; 21:927-937. [PMID: 32078232 DOI: 10.1002/cphc.201901134] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2019] [Revised: 02/13/2020] [Indexed: 11/08/2022]
Abstract
Scientific evidence has shown oxygenates help to reduce dangerous pollutants arising from burning fossil fuel in the automotive sector. For this reason, their use as additives has spread widely. The aim of this work consists in providing a comprehensive identification of the main primary oxidation products of diisopropyl ether (DIPE), one of the most promising among etheric oxygenates. The Cl-initiated oxidation of DIPE is examinated by using a vacuum ultraviolet (VUV) synchrotron radiation at the Advanced Light Source (ALS) of the Lawrence Berkeley National Laboratory (LBNL). Products are identified on the basis of their mass-to-charge ratio, shape of photoionization spectra, adiabatic ionization energies, and chemical kinetic profiles, at three different temperatures (298, 550, and 650 K). Acetone, propanal, propene, and isopropyl acetate have been identified as major reaction products. Acetone is the main primary product. Theoretical calculations using the composite CBS-QB3 method provided useful tools to validate the postulated reaction mechanisms leading to experimentally observed species. The formation of other species is also discussed.
Collapse
Affiliation(s)
- Andrea Giustini
- A. Giustini and Prof. G. Meloni, Department of Physical and Chemical Sciences, University of L'Aquila, L'Aquila, Italy
| | - Giovanni Meloni
- A. Giustini and Prof. G. Meloni, Department of Physical and Chemical Sciences, University of L'Aquila, L'Aquila, Italy.,Prof. G. Meloni, Department of Chemistry, University of San Francisco, San Francisco, California, 94117, United States
| |
Collapse
|
21
|
Xing L, Wang Z, Truhlar DG. Multistructural Anharmonicity Controls the Radical Generation Process in Biofuel Combustion. J Am Chem Soc 2019; 141:18531-18543. [PMID: 31637914 DOI: 10.1021/jacs.9b09194] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The OH radical plays an important role in combustion, and isopentanol (3-methylbutan-1-ol) is a promising sustainable fuel additive and second-generation biofuel. The abstractions of H atoms from fuel molecules are key initiation steps for chain branching in combustion chemistry. In comparison with the more frequently studied ethanol, isopentanol has a longer carbon chain that allows a greater number of products, and experimental work is unavailable for the branching fractions to the various products. However, the site-dependent kinetics of isopentanol with OH radicals are usually experimentally unavailable. Alcohol oxidation by OH is also important in the atmosphere, and in the present study we calculate the rate constants and branching fractions of the hydrogen abstraction reaction of isopentanol by OH radical in a broad temperature range of 298-2400 K, covering temperatures important for atmospheric chemistry and those important for combustion. The calculations are done by multipath variational transition state theory (MP-VTST). With a combination of electronic structure calculations, we determine previously missing thermochemical data. With MP-VTST, a multidimensional tunneling approximation, multiple-structure anharmonicity, and torsional potential anharmonicity, we carried out more realistic rate constant calculations than can be computed by conventional single-structure harmonic transition state theory or by the empirical relations that are currently used in atmospheric and combustion modeling. The roles of various factors in determining the rates are elucidated, and we show that recrossing, tunneling, and multiple structures are all essential for accurate work. We conclude that the multiple structure anharmonicity is the most important correction to conventional transition state theory for this reaction, although recrossing effects and tunneling are by no means insignificant and the tunneling depends significantly on the path. The thermodynamic and kinetics data determined in this work are indispensable for the gas-phase degradation of alcohols in the atmosphere and for the detailed understanding and prediction of ignition mechanisms of biofuels in combustion.
Collapse
Affiliation(s)
- Lili Xing
- Energy and Power Engineering Institute , Henan University of Science and Technology , Luoyang , Henan 471003 , China.,Department of Chemistry, Chemical Theory Center, and Minnesota Supercomputing Institute , University of Minnesota , Minnesota 55455-0431 , United States
| | - Zhandong Wang
- National Synchrotron Radiation Laboratory , University of Science and Technology of China , Hefei , Anhui 230029 , PR China
| | - Donald G Truhlar
- Department of Chemistry, Chemical Theory Center, and Minnesota Supercomputing Institute , University of Minnesota , Minnesota 55455-0431 , United States
| |
Collapse
|
22
|
Potter DG, Blitz MA, Seakins PW. A generic method for determining R + O2 rate parameters via OH regeneration. Chem Phys Lett 2019. [DOI: 10.1016/j.cplett.2019.06.014] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
|
23
|
Davis JC, Koritzke AL, Caravan RL, Antonov IO, Christianson MG, Doner AC, Osborn DL, Sheps L, Taatjes CA, Rotavera B. Influence of the Ether Functional Group on Ketohydroperoxide Formation in Cyclic Hydrocarbons: Tetrahydropyran and Cyclohexane. J Phys Chem A 2019; 123:3634-3646. [PMID: 30865470 DOI: 10.1021/acs.jpca.8b12510] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Photolytically initiated oxidation experiments were conducted on cyclohexane and tetrahydropyran using multiplexed photoionization mass spectrometry to assess the impact of the ether functional group in the latter species on reaction mechanisms relevant to autoignition. Pseudo-first-order conditions, with [O2]0:[R•]0 > 2000, were used to ensure that R• + O2 → products were the dominant reactions. Quasi-continuous, tunable vacuum ultraviolet light from a synchrotron was employed over the range 8.0-11.0 eV to measure photoionization spectra of the products at two pressures (10 and 1520 Torr) and three temperatures (500, 600, and 700 K). Photoionization spectra of ketohydroperoxides were measured in both species and were qualitatively identical, within the limit of experimental noise, to those of analogous species formed in n-butane oxidation. However, differences were noted in the temperature dependence of ketohydroperoxide formation between the two species. Whereas the yield from cyclohexane is evident up to 700 K, ketohydroperoxides in tetrahydropyran were not detected above 650 K. The difference indicates that reaction mechanisms change due to the ether group, likely affecting the requisite •QOOH + O2 addition step. Branching fractions of nine species from tetrahydropyran were quantified with the objective of determining the role of ring-opening reactions in diminishing ketohydroperoxide. The results indicate that products formed from unimolecular decomposition of R• and •QOOH radicals via concerted C-C and C-O β-scission are pronounced in tetrahydropyran and are insignificant in cyclohexane oxidation. The main conclusion drawn is that, under the conditions herein, ring-opening pathways reduce the already low steady-state concentration of •QOOH, which in the case of tetrahydropyran prevents •QOOH + O2 reactions necessary for ketohydroperoxide formation. Carbon balance calculations reveal that products from ring opening of both R• and •QOOH, at 700 K, account for >70% at 10 Torr and >55% at 1520 Torr. Three pathways are confirmed to contribute to the depletion of •QOOH in tetrahydropyran including (i) γ-•QOOH → pentanedial + •OH, (ii) γ-•QOOH → vinyl formate + ethene + •OH, and (iii) γ-•QOOH → 3-butenal + formaldehyde + •OH. Analogous mechanisms in cyclohexane oxidation leading to similar intermediates are compared and, on the basis of mass spectral results, confirm that no such ring-opening reactions occur. The implication from the comparison to cyclohexane is that the ether group in tetrahydropyran increases the propensity for ring-opening reactions and inhibits the formation of ketohydroperoxide isomers that precede chain-branching. On the contrary, the absence of such reactions in cyclohexane enables ketohydroperoxide formation up to 700 K and perhaps higher temperature.
Collapse
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
| | | |
Collapse
|
24
|
Parab PR, Heufer KA, Fernandes RX. Reaction kinetics of hydrogen atom abstraction from isopentanol by the H atom and HO 2˙ radical. Phys Chem Chem Phys 2018. [PMID: 29533404 DOI: 10.1039/c7cp08077h] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Isopentanol is a potential next-generation biofuel for future applications to Homogeneous Charge Compression Ignition (HCCI) engine concepts. To provide insights into the combustion behavior of isopentanol, especially to its auto-ignition behavior which is linked both to efficiency and pollutant formation in real combustion systems, detailed quantum chemical studies for crucial reactions are desired. H-Abstraction reaction rates from fuel molecules are key initiation steps for chain branching required for auto-ignition. In this study, rate constants are determined for the hydrogen atom abstraction reactions from isopentanol by the H atom and HO2˙ radical by implementing the CBS-QB3 composite method. For the treatment of the internal rotors, a Pitzer-Gwinn-like approximation is applied. On comparing the computed reaction energies, the highest exothermicity (ΔE = -46 kJ mol-1) is depicted for Hα abstraction by the H atom whereas the lowest endothermicity (ΔE = 29 kJ mol-1) is shown for the abstraction of Hα by the HO2˙ radical. The formation of hydrogen bonding is found to affect the kinetics of the H atom abstraction reactions by the HO2˙ radical. Further above 750 K, the calculated high pressure limit rate constants indicate that the total contribution from delta carbon sites (Cδ) is predominant for hydrogen atom abstraction by the H atom and HO2˙ radical.
Collapse
Affiliation(s)
- Prajakta Rajaram Parab
- Physico Chemical Fundamentals of Combustion, RWTH Aachen University, Templergraben 55, 52056 Aachen, Germany.
| | | | | |
Collapse
|
25
|
Jones PJ, Riser B, Zhang J. Flash Pyrolysis of t-Butyl Hydroperoxide and Di-t-butyl Peroxide: Evidence of Roaming in the Decomposition of Organic Hydroperoxides. J Phys Chem A 2017; 121:7846-7853. [PMID: 28956925 DOI: 10.1021/acs.jpca.7b07359] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Thermal decomposition of t-butyl hydroperoxide and di-t-butyl peroxide was investigated using flash pyrolysis (in a short reaction time of <100 μs) and vacuum-ultraviolet (λ = 118.2 nm) single-photon ionization time-of-flight mass spectrometry (VUV-SPI-TOFMS) at temperatures up to 1120 K and quantum computational methods. Acetone and methyl radical were detected as the predominant products in the initial decomposition of di-t-butyl peroxide via O-O bond fission. In the initial dissociation of t-butyl hydroperoxide, acetone, methyl radical, isobutylene, and isobutylene oxide products were identified. The novel detection of the unimolecular formation of isobutylene oxide, as supported by the computational study, was found to proceed via a roaming hydroxyl radical facilitated by a hydrogen-bonded intermediate. This new pathway could provide a new class of reactions to consider in the modeling of the low temperature oxidation of alkanes.
Collapse
Affiliation(s)
- Paul J Jones
- Department of Chemistry and ‡Air Pollution Research Center, University of California , Riverside, California 92521, United States
| | - Blake Riser
- Department of Chemistry and ‡Air Pollution Research Center, University of California , Riverside, California 92521, United States
| | - Jingsong Zhang
- Department of Chemistry and ‡Air Pollution Research Center, University of California , Riverside, California 92521, United States
| |
Collapse
|
26
|
DeVine JA, Weichman ML, Babin MC, Neumark DM. Slow photoelectron velocity-map imaging of cold tert-butyl peroxide. J Chem Phys 2017; 147:013915. [DOI: 10.1063/1.4979951] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Jessalyn A. DeVine
- Department of Chemistry, University of California, Berkeley, California 94720, USA
| | - Marissa L. Weichman
- Department of Chemistry, University of California, Berkeley, California 94720, USA
| | - Mark C. Babin
- Department of Chemistry, University of California, Berkeley, California 94720, USA
| | - Daniel M. Neumark
- Department of Chemistry, University of California, Berkeley, California 94720, USA
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| |
Collapse
|
27
|
Price C, Fathi Y, Meloni G. Absolute photoionization cross sections of two cyclic ketones: cyclopentanone and cyclohexanone. JOURNAL OF MASS SPECTROMETRY : JMS 2017; 52:259-270. [PMID: 28231419 DOI: 10.1002/jms.3923] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2017] [Revised: 02/15/2017] [Accepted: 02/17/2017] [Indexed: 06/06/2023]
Abstract
Absolute photoionization cross sections for cyclopentanone and cyclohexanone, as well as partial ionization cross sections for the dissociative ionized fragments, are presented in this investigation. Experiments are performed via a multiplexed photoionization mass spectrometer utilizing vacuum ultraviolet (VUV) synchrotron radiation supplied by the Advanced Light Source of Lawrence Berkeley National Laboratory. These results allow the quantification of these species that is relevant to investigate the kinetics and combustion reactions of potential biofuels. The CBS-QB3 calculated values for the adiabatic ionization energies agree well with the experimental values, and the identification of possible dissociative fragments is discussed for both systems. Copyright © 2017 John Wiley & Sons, Ltd.
Collapse
Affiliation(s)
- Chelsea Price
- Department of Chemistry, University of San Francisco, CA, 94117, USA
| | - Yasmin Fathi
- Department of Chemistry, University of San Francisco, CA, 94117, USA
| | - Giovanni Meloni
- Department of Chemistry, University of San Francisco, CA, 94117, USA
| |
Collapse
|
28
|
Fathi Y, Price C, Meloni G. Low-Temperature Synchrotron Photoionization Study of 2-Methyl-3-buten-2-ol (MBO) Oxidation Initiated by O( 3P) Atoms in the 298-650 K Range. J Phys Chem A 2017; 121:2936-2950. [PMID: 28363019 DOI: 10.1021/acs.jpca.6b12421] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
This work studies the oxidation of 2-methyl-3-buten-2-ol initiated by O(3P) atoms. The oxidation was investigated at room temperature, 550, and 650 K. Using the synchrotron radiation from the Advanced Light Source (ALS) of the Lawrence Berkley National Laboratory, reaction intermediates and products were studied by multiplexed photoionization mass spectrometry. Mass-to-charge ratios, kinetic time traces, photoionization spectra, and adiabatic ionization energies for each primary reaction species were obtained and used to characterize their identity. Using electronic structure calculations, potential energy surface scans of the different species produced throughout the oxidation were examined and presented in this paper to further validate the primary chemistry occurring. Branching fractions of primary products at all three temperatures were also provided. At room temperature only three primary products formed: ethenol (26.6%), acetaldehyde (4.2%), and acetone (53.4%). At 550 and 650 K the same primary products were observed in addition to propene (5.1%, 11.2%), ethenol (18.1%, 2.8%), acetaldehyde (8.9%, 5.7%), cyclobutene (1.6%, 10.8%), 1-butene (2.0%, 10.9%), trans-2-butene (3.2%, 23.1%), acetone (50.4%, 16.8%), 3-penten-2-one (1.0%, 11.5%), and 3-methyl-2-butenal (0.9%, 2.5%), where the first branching fraction value in parentheses corresponds to the 550 K data. At the highest temperature, a small amount of propyne (1.0%) was also observed.
Collapse
Affiliation(s)
- Yasmin Fathi
- Department of Chemistry, University of San Francisco , San Francisco, California 94117 United States
| | - Chelsea Price
- Department of Chemistry, University of San Francisco , San Francisco, California 94117 United States
| | - Giovanni Meloni
- Department of Chemistry, University of San Francisco , San Francisco, California 94117 United States
| |
Collapse
|
29
|
Winfough M, Yao R, Ng M, Catani K, Meloni G. Synchrotron Photoionization Investigation of the Oxidation of Ethyl tert-Butyl Ether. J Phys Chem A 2017; 121:1460-1469. [PMID: 28152311 DOI: 10.1021/acs.jpca.6b11507] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The oxidation of ethyl tert-butyl ether (ETBE), a widely used fuel oxygenated additive, is investigated using Cl atoms as initiators in the presence of oxygen. The reaction is carried out at 293, 550, and 700 K. Reaction products are probed by a multiplexed chemical kinetics photoionization mass spectrometer coupled with the synchrotron radiation produced at the Advanced Light Source (ALS) of the Lawrence Berkeley National Laboratory. Products are identified on the basis of mass-to-charge ratio, ionization energies, and shape of photoionization spectra. Reaction pathways are proposed together with detected primary products.
Collapse
Affiliation(s)
- Matthew Winfough
- Department of Chemistry, University of San Francisco , San Francisco, California 94117-1080, United States
| | - Rong Yao
- Department of Chemistry, University of San Francisco , San Francisco, California 94117-1080, United States
| | - Martin Ng
- Department of Chemistry, University of San Francisco , San Francisco, California 94117-1080, United States
| | - Katherine Catani
- Department of Chemistry, University of San Francisco , San Francisco, California 94117-1080, United States
| | - Giovanni Meloni
- Department of Chemistry, University of San Francisco , San Francisco, California 94117-1080, United States
| |
Collapse
|
30
|
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] [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
| |
Collapse
|
31
|
Parandaman A, Rajakumar B. Thermal Decomposition of 2-Pentanol: A Shock Tube Study and RRKM Calculations. J Phys Chem A 2016; 120:8024-8036. [DOI: 10.1021/acs.jpca.6b06386] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- A. Parandaman
- Department
of chemistry, Indian Institute of Technology Madras, Chennai 600036, India
| | - B. Rajakumar
- Department
of chemistry, Indian Institute of Technology Madras, Chennai 600036, India
| |
Collapse
|
32
|
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] [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
| |
Collapse
|
33
|
Kohse-Höinghaus K. Combustion Chemistry Diagnostics for Cleaner Processes. Chemistry 2016; 22:13390-401. [DOI: 10.1002/chem.201602676] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2016] [Indexed: 11/10/2022]
|
34
|
Muller G, Scheer A, Osborn DL, Taatjes CA, Meloni G. Low Temperature Chlorine-Initiated Oxidation of Small-Chain Methyl Esters: Quantification of Chain-Terminating HO2-Elimination Channels. J Phys Chem A 2016; 120:1677-90. [DOI: 10.1021/acs.jpca.6b00148] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Giel Muller
- University of San Francisco, San Francisco, California 94117, United States
| | - Adam Scheer
- Pacific Gas and Electric Company, 245 Market Street, San Francisco, California 94111, United States
| | - David L. Osborn
- Sandia National Laboratories, Livermore, California 94551, United States
| | - Craig A. Taatjes
- Sandia National Laboratories, Livermore, California 94551, United States
| | - Giovanni Meloni
- University of San Francisco, San Francisco, California 94117, United States
| |
Collapse
|
35
|
Ng MY, Bryan BM, Nelson J, Meloni G. Study of tert-Amyl Methyl Ether Low Temperature Oxidation Using Synchrotron Photoionization Mass Spectrometry. J Phys Chem A 2015. [PMID: 26200937 DOI: 10.1021/acs.jpca.5b05223] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
This paper examines the oxidation reaction of tert-amyl methyl ether (TAME), an oxygenated fuel additive, with chlorine radical initiators in the presence of oxygen. Data are collected at 298, 550, and 700 K. Reaction intermediates and products are probed by a multiplexed chemical kinetics synchrotron photoionization mass spectrometer (SPIMS) and characterized on the basis of the mass-to-charge ratio, ionization energy, and photoionization spectra. Branching fractions of primary products are obtained at the different reaction temperatures. CBS-QB3 computations are also carried out to study the potential energy surface of the investigated reactions to validate detected primary products.
Collapse
Affiliation(s)
- Martin Y Ng
- Department of Chemistry, University of San Francisco, San Francisco, California 94117, United States
| | - Brittany M Bryan
- Department of Chemistry, University of San Francisco, San Francisco, California 94117, United States
| | - Jordan Nelson
- Department of Chemistry, University of San Francisco, San Francisco, California 94117, United States
| | - Giovanni Meloni
- Department of Chemistry, University of San Francisco, San Francisco, California 94117, United States
| |
Collapse
|
36
|
Savee JD, Borkar S, Welz O, Sztáray B, Taatjes CA, Osborn DL. Multiplexed Photoionization Mass Spectrometry Investigation of the O(3P) + Propyne Reaction. J Phys Chem A 2015; 119:7388-403. [DOI: 10.1021/acs.jpca.5b00491] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- John D. Savee
- Combustion
Research Facility, Sandia National Laboratories, Mail Stop 9055, Livermore, California 94551-0969, United States
| | - Sampada Borkar
- Department
of Chemistry, University of the Pacific, Stockton, California 95211, United States
| | - Oliver Welz
- Combustion
Research Facility, Sandia National Laboratories, Mail Stop 9055, Livermore, California 94551-0969, United States
| | - Bálint Sztáray
- Department
of Chemistry, University of the Pacific, Stockton, California 95211, United States
| | - Craig A. Taatjes
- Combustion
Research Facility, Sandia National Laboratories, Mail Stop 9055, Livermore, California 94551-0969, United States
| | - David L. Osborn
- Combustion
Research Facility, Sandia National Laboratories, Mail Stop 9055, Livermore, California 94551-0969, United States
| |
Collapse
|
37
|
Scheer AM, Welz O, Vasu SS, Osborn DL, Taatjes CA. Low temperature (550-700 K) oxidation pathways of cyclic ketones: dominance of HO2-elimination channels yielding conjugated cyclic coproducts. Phys Chem Chem Phys 2015; 17:12124-34. [PMID: 25877515 DOI: 10.1039/c4cp06097k] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The low-temperature oxidation of three cyclic ketones, cyclopentanone (CPO; C5H8=O), cyclohexanone (CHO; C6H10=O), and 2-methyl-cyclopentanone (2-Me-CPO; CH3-C5H7=O), is studied between 550 and 700 K and at 4 or 8 Torr total pressure. Initial fuel radicals R are formed via fast H-abstraction from the ketones by laser-photolytically generated chlorine atoms. Intermediates and products from the subsequent reactions of these radicals in the presence of excess O2 are probed with time and isomeric resolution using multiplexed photoionization mass spectrometry with tunable synchrotron ionizing radiation. For CPO and CHO the dominant product channel in the R + O2 reactions is chain-terminating HO2-elimination yielding the conjugated cyclic coproducts 2-cyclopentenone and 2-cyclohexenone, respectively. Results on oxidation of 2-Me-CPO also show a dominant contribution from HO2-elimination. The photoionization spectrum of the co-product suggests formation of 2-methyl-2-cyclopentenone and/or 2-cyclohexenone, resulting from a rapid Dowd-Beckwith rearrangement, preceding addition to O2, of the initial (2-oxocyclopentyl)methyl radical to 3-oxocyclohexyl. Cyclic ethers, markers for hydroperoxyalkyl radicals (QOOH), key intermediates in chain-propagating and chain-branching low-temperature combustion pathways, are only minor products. The interpretation of the experimental results is supported by stationary point calculations on the potential energy surfaces of the associated R + O2 reactions at the CBS-QB3 level. The calculations indicate that HO2-elimination channels are energetically favored and product formation via QOOH is disfavored. The prominence of chain-terminating pathways linked with HO2 formation in low-temperature oxidation of cyclic ketones suggests little low-temperature reactivity of these species as fuels in internal combustion engines.
Collapse
Affiliation(s)
- Adam M Scheer
- Combustion Research Facility, Sandia National Laboratories, MS 9055, Livermore, CA 94551, USA.
| | | | | | | | | |
Collapse
|
38
|
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] [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
| |
Collapse
|
39
|
Dodson LG, Shen L, Savee JD, Eddingsaas NC, Welz O, Taatjes CA, Osborn DL, Sander SP, Okumura M. VUV photoionization cross sections of HO2, H2O2, and H2CO. J Phys Chem A 2015; 119:1279-91. [PMID: 25621533 DOI: 10.1021/jp508942a] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The absolute vacuum ultraviolet (VUV) photoionization spectra of the hydroperoxyl radical (HO2), hydrogen peroxide (H2O2), and formaldehyde (H2CO) have been measured from their first ionization thresholds to 12.008 eV. HO2, H2O2, and H2CO were generated from the oxidation of methanol initiated by pulsed-laser-photolysis of Cl2 in a low-pressure slow flow reactor. Reactants, intermediates, and products were detected by time-resolved multiplexed synchrotron photoionization mass spectrometry. Absolute concentrations were obtained from the time-dependent photoion signals by modeling the kinetics of the methanol oxidation chemistry. Photoionization cross sections were determined at several photon energies relative to the cross section of methanol, which was in turn determined relative to that of propene. These measurements were used to place relative photoionization spectra of HO2, H2O2, and H2CO on an absolute scale, resulting in absolute photoionization spectra.
Collapse
Affiliation(s)
- Leah G Dodson
- Division of Chemistry and Chemical Engineering and §NASA Jet Propulsion Laboratory, California Institute of Technology , Pasadena, California 91125, United States
| | | | | | | | | | | | | | | | | |
Collapse
|
40
|
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] [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.
Collapse
Affiliation(s)
- Brandon Rotavera
- Combustion Chemistry Department, Combustion Research Facility, Sandia National Laboratories , Livermore, California 94550-0969, United States
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
41
|
Auzmendi-Murua I, Bozzelli JW. Thermochemical Properties and Bond Dissociation Enthalpies of 3- to 5-Member Ring Cyclic Ether Hydroperoxides, Alcohols, and Peroxy Radicals: Cyclic Ether Radical + 3O2 Reaction Thermochemistry. J Phys Chem A 2014; 118:3147-67. [DOI: 10.1021/jp412590g] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Itsaso Auzmendi-Murua
- Department of Chemistry and
Chemical Engineering, New Jersey Institute of Technology, Newark, New Jersey 07102, United States
| | - Joseph W. Bozzelli
- Department of Chemistry and
Chemical Engineering, New Jersey Institute of Technology, Newark, New Jersey 07102, United States
| |
Collapse
|
42
|
Scheer AM, Welz O, Zádor J, Osborn DL, Taatjes CA. Low-temperature combustion chemistry of novel biofuels: resonance-stabilized QOOH in the oxidation of diethyl ketone. Phys Chem Chem Phys 2014; 16:13027-40. [DOI: 10.1039/c3cp55468f] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
43
|
Scheer AM, Welz O, Sasaki DY, Osborn DL, Taatjes CA. Facile Rearrangement of 3-Oxoalkyl Radicals is Evident in Low-Temperature Gas-Phase Oxidation of Ketones. J Am Chem Soc 2013; 135:14256-65. [DOI: 10.1021/ja405892y] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [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
| | - Oliver Welz
- Combustion Research
Facility, Sandia National Laboratories, MS 9055, Livermore, California 94551, United States
| | - Darryl Y. Sasaki
- Biological
and
Materials Science, Sandia National Laboratories, MS 9292, Livermore, California 94551, United States
| | - David L. Osborn
- 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
| |
Collapse
|
44
|
Savee JD, Lockyear JF, Borkar S, Eskola AJ, Welz O, Taatjes CA, Osborn DL. Note: Absolute photoionization cross-section of the vinyl radical. J Chem Phys 2013; 139:056101. [DOI: 10.1063/1.4817320] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
|
45
|
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] [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
| |
Collapse
|
46
|
Welz O, Klippenstein SJ, Harding LB, Taatjes CA, Zádor J. Unconventional Peroxy Chemistry in Alcohol Oxidation: The Water Elimination Pathway. J Phys Chem Lett 2013; 4:350-354. [PMID: 26281722 DOI: 10.1021/jz302004w] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Predictive simulation for designing efficient engines requires detailed modeling of combustion chemistry, for which the possibility of unknown pathways is a continual concern. Here, we characterize a low-lying water elimination pathway from key hydroperoxyalkyl (QOOH) radicals derived from alcohols. The corresponding saddle-point structure involves the interaction of radical and zwitterionic electronic states. This interaction presents extreme difficulties for electronic structure characterizations, but we demonstrate that these properties of this saddle point can be well captured by M06-2X and CCSD(T) methods. Experimental evidence for the existence and relevance of this pathway is shown in recently reported data on the low-temperature oxidation of isopentanol and isobutanol. In these systems, water elimination is a major pathway, and is likely ubiquitous in low-temperature alcohol oxidation. These findings will substantially alter current alcohol oxidation mechanisms. Moreover, the methods described will be useful for the more general phenomenon of interacting radical and zwitterionic states.
Collapse
Affiliation(s)
- Oliver Welz
- †Combustion Research Facility, Sandia National Laboratories, Livermore, California 94551-0969, United States
| | - Stephen J Klippenstein
- ‡Chemical Sciences and Engineering Division, Argonne National Laboratory, Argonne, Illinois 60439, United States
| | - Lawrence B Harding
- ‡Chemical Sciences and Engineering Division, Argonne National Laboratory, Argonne, Illinois 60439, United States
| | - Craig A Taatjes
- †Combustion Research Facility, Sandia National Laboratories, Livermore, California 94551-0969, United States
| | - Judit Zádor
- †Combustion Research Facility, Sandia National Laboratories, Livermore, California 94551-0969, United States
| |
Collapse
|
47
|
Zádor J, Huang H, Welz O, Zetterberg J, Osborn DL, Taatjes CA. Directly measuring reaction kinetics of ˙QOOH – a crucial but elusive intermediate in hydrocarbon autoignition. Phys Chem Chem Phys 2013; 15:10753-60. [DOI: 10.1039/c3cp51185e] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
48
|
Zhao L, Ye L, Zhang F, Zhang L. Thermal Decomposition of 1-Pentanol and Its Isomers: A Theoretical Study. J Phys Chem A 2012; 116:9238-44. [DOI: 10.1021/jp305885s] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Long Zhao
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei,
Anhui 230029, P. R. China
| | - Lili Ye
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei,
Anhui 230029, P. R. China
| | - Feng Zhang
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei,
Anhui 230029, P. R. China
| | - Lidong Zhang
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei,
Anhui 230029, P. R. China
| |
Collapse
|
49
|
Ray AW, Taatjes CA, Welz O, Osborn DL, Meloni G. Synchrotron photoionization measurements of OH-initiated cyclohexene oxidation: ring-preserving products in OH + cyclohexene and hydroxycyclohexyl + O2 reactions. J Phys Chem A 2012; 116:6720-30. [PMID: 22631211 DOI: 10.1021/jp3022437] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Earlier synchrotron photoionization mass spectrometry experiments suggested a prominent ring-opening channel in the OH-initiated oxidation of cyclohexene, based on comparison of product photoionization spectra with calculated spectra of possible isomers. The present work re-examines the OH + cyclohexene reaction, measuring the isomeric products of OH-initiated oxidation of partially and fully deuterated cyclohexene. In particular, the directly measured photoionization spectrum of 2-cyclohexen-1-ol differs substantially from the previously calculated Franck-Condon envelope, and the product spectrum can be fit with no contribution from ring-opening. Measurements of H(2)O(2) photolysis in the presence of C(6)D(10) establish that the addition-elimination product incorporates the hydrogen atom from the hydroxyl radical reactant and loses a hydrogen (a D atom in this case) from the ring. Investigation of OH + cyclohexene-4,4,5,5-d(4) confirms this result and allows mass discrimination of different abstraction pathways. Products of 2-hydroxycyclohexyl-d(10) reaction with O(2) are observed upon adding a large excess of O(2) to the OH + C(6)D(10) system.
Collapse
Affiliation(s)
- Amelia W Ray
- Department of Chemistry, University of San Francisco, San Francisco, California 94117, USA
| | | | | | | | | |
Collapse
|