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Lin C, Hu R, Xie P, Zhang G, Liu X, Tong J, Liu W. A three-channel thermal dissociation cavity ring-down spectrometer for simultaneous measurement of ambient total peroxy nitrates, total alkyl nitrates, and NO 2. Talanta 2024; 270:125524. [PMID: 38128285 DOI: 10.1016/j.talanta.2023.125524] [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: 07/12/2023] [Revised: 11/27/2023] [Accepted: 12/04/2023] [Indexed: 12/23/2023]
Abstract
A newly constructed thermal dissociation cavity ring-down spectrometer (TD-CRDS) for the simultaneous measurement of ambient total peroxy nitrates (ΣPNs, RO2NO2), total alkyl nitrates (ΣANs, RONO2), and NO2 was presented in this work. ΣPNs and ΣANs were detected as NO2 with the CRDS instrument after thermal dissociation. PNs and ANs completely dissociated at 180 °C and 360 °C, with conversion efficiencies of 96 % and 99 %, respectively. The effects of NO2 and NO on measurement in different temperatures and two types of thermal dissociation inlet (TDI) were further explored. The influence of ambient NO2 and NO on PNs and ANs in the improved TDI (TDI-2) was significantly improved. To further enhance the measurement accuracy, the consistency of the observed NO2 in the three channels was tested, which achieved good agreement. The detection limits of the TD-CRDS instrument for NO2, ΣPNs, and ΣANs were determined as 6.5, 6.8, and 8.6 pptv (10 s, 1σ), respectively. Observations of PNs and ANs were conducted in a suburban site in Hefei, China, from September 2-30, 2021, using the TD-CRDS instrument, and the consecutive time series of PNs and ANs were derived, verifying the capability of the TD-CRDS instrument for continuous field observations of ΣPNs and ΣANs.
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Affiliation(s)
- Chuan Lin
- Key Laboratory of Environmental Optics and Technology, Anhui Institute of Optics and Fine Mechanics, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, 230031, China; University of Science and Technology of China, Hefei, 230027, China
| | - Renzhi Hu
- Key Laboratory of Environmental Optics and Technology, Anhui Institute of Optics and Fine Mechanics, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, 230031, China.
| | - Pinhua Xie
- Key Laboratory of Environmental Optics and Technology, Anhui Institute of Optics and Fine Mechanics, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, 230031, China; University of Science and Technology of China, Hefei, 230027, China; University of Chinese Academy of Sciences, Beijing, 100049, China.
| | - Guoxian Zhang
- Key Laboratory of Environmental Optics and Technology, Anhui Institute of Optics and Fine Mechanics, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, 230031, China
| | - Xiaoyan Liu
- College of Pharmacy, Anhui Medical University, Hefei, 230032, China
| | - Jinzhao Tong
- University of Science and Technology of China, Hefei, 230027, China
| | - Wenqing Liu
- Key Laboratory of Environmental Optics and Technology, Anhui Institute of Optics and Fine Mechanics, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, 230031, China
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2
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Troß J, Carter-Fenk K, Cole-Filipiak NC, Schrader P, Word M, McCaslin LM, Head-Gordon M, Ramasesha K. Excited-State Dynamics during Primary C-I Homolysis in Acetyl Iodide Revealed by Ultrafast Core-Level Spectroscopy. J Phys Chem A 2023; 127:4103-4114. [PMID: 37103479 DOI: 10.1021/acs.jpca.3c01414] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/28/2023]
Abstract
In typical carbonyl-containing molecules, bond dissociation events follow initial excitation to nπC═O* states. However, in acetyl iodide, the iodine atom gives rise to electronic states with mixed nπC═O* and nσC-I* character, leading to complex excited-state dynamics, ultimately resulting in dissociation. Using ultrafast extreme ultraviolet (XUV) transient absorption spectroscopy and quantum chemical calculations, we present an investigation of the primary photodissociation dynamics of acetyl iodide via time-resolved spectroscopy of core-to-valence transitions of the I atom after 266 nm excitation. The probed I 4d-to-valence transitions show features that evolve on sub-100-fs time scales, reporting on excited-state wavepacket evolution during dissociation. These features subsequently evolve to yield spectral signatures corresponding to free iodine atoms in their spin-orbit ground and excited states with a branching ratio of 1.1:1 following dissociation of the C-I bond. Calculations of the valence excitation spectrum via equation-of-motion coupled cluster with single and double substitutions (EOM-CCSD) show that initial excited states are of spin-mixed character. From the initially pumped spin-mixed state, we use a combination of time-dependent density functional theory (TDDFT)-driven nonadiabatic ab initio molecular dynamics and EOM-CCSD calculations of the N4,5 edge to reveal a sharp inflection point in the transient XUV signal that corresponds to rapid C-I homolysis. By examining the molecular orbitals involved in the core-level excitations at and around this inflection point, we are able to piece together a detailed picture of C-I bond photolysis in which d → σ* transitions give way to d → p excitations as the bond dissociates. We also report theoretical predictions of short-lived, weak 4d → 5d transitions in acetyl iodide, validated by weak bleaching in the experimental transient XUV spectra. This joint experimental-theoretical effort has thus unraveled the detailed electronic structure and dynamics of a strongly spin-orbit coupled system.
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Affiliation(s)
- Jan Troß
- Combustion Research Facility, Sandia National Laboratories, Livermore, California 94550, United States
| | - Kevin Carter-Fenk
- Kenneth S. Pitzer Center for Theoretical Chemistry, Department of Chemistry, University of California, Berkeley, California 94720, United States
| | - Neil C Cole-Filipiak
- Combustion Research Facility, Sandia National Laboratories, Livermore, California 94550, United States
| | - Paul Schrader
- Combustion Research Facility, Sandia National Laboratories, Livermore, California 94550, United States
| | - Mi'Kayla Word
- Combustion Research Facility, Sandia National Laboratories, Livermore, California 94550, United States
| | - Laura M McCaslin
- Combustion Research Facility, Sandia National Laboratories, Livermore, California 94550, United States
| | - Martin Head-Gordon
- Kenneth S. Pitzer Center for Theoretical Chemistry, Department of Chemistry, University of California, Berkeley, California 94720, United States
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Krupa Ramasesha
- Combustion Research Facility, Sandia National Laboratories, Livermore, California 94550, United States
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3
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Li Y, Wang Y, Zhang RM, He X, Xu X. Comprehensive Theoretical Study on Four Typical Intramolecular Hydrogen Shift Reactions of Peroxy Radicals: Multireference Character, Recommended Model Chemistry, and Kinetics. J Chem Theory Comput 2023. [PMID: 37164004 DOI: 10.1021/acs.jctc.3c00033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Intramolecular hydrogen shift reactions in peroxy radicals (RO2• → •QOOH) play key roles in the low-temperature combustion and in the atmospheric chemistry. In the present study, we found that a mild-to-moderate multireference character of a potential energy surface (PES) is widely present in four typical hydrogen shift reactions of peroxy radicals (RO2•, R = ethyl, vinyl, formyl methyl, and acetyl) by a systematic assessment based on the T1 diagnostic, %TAE diagnostic, M diagnostic, and contribution of the dominant configuration of the reference CASSCF wavefunction (C02). To assess the effects of these inherent multireference characters on electronic structure calculations, we compared the PESs of the four reactions calculated by the multireference method CASPT2 in the complete basis set (CBS) limit, single-reference method CCSD(T)-F12, and single-reference-based composite method WMS. The results showed that ignoring the multireference character will introduce a mean unsigned deviation (MUD) of 0.46-1.72 kcal/mol from CASPT2/CBS results by using the CCSD(T)-F12 method or a MUD of 0.49-1.37 kcal/mol by WMS for three RO2• reactions (R = vinyl, formyl methyl, and acetyl) with a stronger multireference character. Further tests by single-reference Kohn-Sham (KS) density functional theory methods showed even larger deviations. Therefore, we specifically developed a new hybrid meta-generalized gradient approximation (GGA) functional M06-HS for the four typical H-shift reactions of peroxy radicals based on the WMS results for the ethyl peroxy radical reaction and on the CASPT2/CBS results for the others. The M06-HS method has an averaged MUD of 0.34 kcal/mol over five tested basis sets against the benchmark PESs, performing best in the tested 38 KS functionals. Last, in a temperature range of 200-3000 K, with the new functional, we calculated the high-pressure-limit rate coefficients of these H-shift reactions by the multi-structural variational transition-state theory with the small-curvature tunneling approximation (MS-CVT/SCT) and the thermochemical properties of all of the involved key radicals by the multi-structural torsional (MS-T) anharmonicity approximation method.
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Affiliation(s)
- Yan Li
- Center for Combustion Energy, Department of Energy and Power Engineering, and Key Laboratory for Thermal Science and Power Engineering of Ministry of Education, Tsinghua University, Beijing 100084, China
| | - Ying Wang
- The National and Local Joint Engineering Laboratory of Animal Peptide Drug Development, College of Life Sciences, Hunan Normal University, Changsha 410081, Hunan, China
- Peptide and Small Molecule Drug R&D Platform, Furong Laboratory, Hunan Normal University, Changsha 410081, Hunan, China
| | - Rui Ming Zhang
- Center for Combustion Energy, Department of Energy and Power Engineering, and Key Laboratory for Thermal Science and Power Engineering of Ministry of Education, Tsinghua University, Beijing 100084, China
| | - Xiao He
- Shanghai Engineering Research Center of Molecular Therapeutics and New Drug Development, Shanghai Frontiers Science Center of Molecule Intelligent Syntheses, School of Chemistry and Molecular Engineering, East China Normal University, Shanghai 200062, China
- New York University-East China Normal University Center for Computational Chemistry, New York University Shanghai, Shanghai 200062, China
| | - Xuefei Xu
- Center for Combustion Energy, Department of Energy and Power Engineering, and Key Laboratory for Thermal Science and Power Engineering of Ministry of Education, Tsinghua University, Beijing 100084, China
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4
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Suresh P, Prasanna Kumari S, Krishna Reddy SM, Anthony SP, Thamotharan S, Selva Ganesan S. Radical directed regioselective functionalization of diverse alkene derivatives. NEW J CHEM 2022. [DOI: 10.1039/d2nj02824g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Regioselective vicinal difunctionalization of diverse alkene derivatives was successfully carried out using readily available carboxylic acids.
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Affiliation(s)
- Pavithira Suresh
- Department of Chemistry, School of Chemical and Biotechnology, SASTRA Deemed University, Thanjavur, 613401, Tamil Nadu, India
| | - Subramaniyan Prasanna Kumari
- Department of Chemistry, School of Chemical and Biotechnology, SASTRA Deemed University, Thanjavur, 613401, Tamil Nadu, India
| | | | - Savarimuthu Philip Anthony
- Department of Chemistry, School of Chemical and Biotechnology, SASTRA Deemed University, Thanjavur, 613401, Tamil Nadu, India
| | - Subbiah Thamotharan
- Biomolecular Crystallography Laboratory, Department of Bioinformatics, School of Chemical and Biotechnology, SASTRA Deemed University, Thanjavur, 613401, Tamil Nadu, India
| | - Subramaniapillai Selva Ganesan
- Department of Chemistry, School of Chemical and Biotechnology, SASTRA Deemed University, Thanjavur, 613401, Tamil Nadu, India
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5
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Zheng H, Zhang L, Zhang G, Gan Y, Xie M, Zhang S. UV-Induced Redox Conversion of Tellurite by Biacetyl. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021; 55:16646-16654. [PMID: 34889589 DOI: 10.1021/acs.est.1c05318] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Tellurium (Te) is a rare element of great value, but it exists mainly in the toxic form of tellurite (TeIV) in water. Effective approaches that are able to reduce the toxicity and recover Te from contaminated water are highly needed. Here, we developed a simple but effective way to reduce toxic TeIV to widely applicable elemental Te0. With the combination of ultraviolet (UV) and biacetyl (BD), the oxidation state of Te could be feasibly changed from IV to 0 or VI. The consumption of dissolved oxygen (DO) was a key factor in the redox conversion of TeIV. Under UV irradiation, BD was first cleaved to acetyl radicals, which could then combine with water molecules to form more reductive diol radicals or combine with DO to form strongly oxidative peroxide radicals. Even without deoxygenation, the UV/BD system could rapidly change from being oxidative to being reductive because of the fast depletion of DO. Owing to the high quantum yield of the acetyl radical, the reduction efficiency of the UV/BD system was about 1 order of magnitude higher than that of UV/sulfite and was more efficient than the commonly used biological methods. This work provides a proof of concept for the reduction of tellurite, which could have relevant implications for water treatment and resource recovery applications.
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Affiliation(s)
- Hongcen Zheng
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, China
| | - Li Zhang
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, China
| | - Guoyang Zhang
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, China
| | - Yonghai Gan
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, China
| | - Min Xie
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, China
| | - Shujuan Zhang
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, China
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6
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Doner AC, Davis MM, Koritzke AL, Christianson MG, Turney JM, Schaefer HF, Sheps L, Osborn DL, Taatjes CA, Rotavera B. Isomer‐dependent reaction mechanisms of cyclic ether intermediates:cis‐2,3‐dimethyloxirane andtrans‐2,3‐dimethyloxirane. INT J CHEM KINET 2020. [DOI: 10.1002/kin.21429] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Anna C. Doner
- Department of Chemistry University of Georgia Athens GA USA
| | - Matthew M. Davis
- Department of Chemistry University of Georgia Athens GA USA
- Center for Computational Quantum Chemistry University of Georgia Athens GA USA
| | | | | | - Justin M. Turney
- Center for Computational Quantum Chemistry University of Georgia Athens GA USA
| | - Henry F. Schaefer
- Department of Chemistry University of Georgia Athens GA USA
- Center for Computational Quantum Chemistry University of Georgia Athens GA USA
| | - Leonid Sheps
- Combustion Research Facility Sandia National Laboratories Livermore CA USA
| | - David L. Osborn
- Combustion Research Facility Sandia National Laboratories Livermore CA USA
| | - Craig A. Taatjes
- Combustion Research Facility Sandia National Laboratories Livermore CA USA
| | - Brandon Rotavera
- Department of Chemistry University of Georgia Athens GA USA
- College of Engineering University of Georgia Athens GA USA
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7
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Wu B, Zhang L, Wei S, Ou'Yang L, Yin R, Zhang S. Reduction of chromate with UV/diacetyl for the final effluent to be below the discharge limit. JOURNAL OF HAZARDOUS MATERIALS 2020; 389:121841. [PMID: 31848094 DOI: 10.1016/j.jhazmat.2019.121841] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2019] [Revised: 12/05/2019] [Accepted: 12/05/2019] [Indexed: 06/10/2023]
Abstract
Reduction of Cr(VI) to Cr(III) is helpful to lower the toxicity risk and also necessary for the removal of chromium from waste streams through alkaline precipitation. We compared the reduction of Cr(VI) in six UV systems with oxalic acid (OA), ethylenediaminetetraacetic acid (EDTA), salicylic acid (SA), hydroquinone (HQ), acetylacetone (AA) and diacetyl (BD) as chelating or non-chelating photo-activators. Overall, HQ, AA and BD were much more efficient than the carboxylic acids for the photo-reduction of Cr(VI). By introduction of UV to HQ system, the pseudo-first-order rate constant of Cr(VI) reduction at pH 5.1 was increased about 50 times. However, due to the formation of colloidal polymers, the UV/HQ treated solutions were dark in color and had a high turbidity (82 NTU). The effects of AA and BD on the photoreduction of Cr(VI) were similar. The UV/BD treated solution was colorless and clear with a turbidity lower than 1 NTU and a residual Cr less than 0.1 mg/L. The results demonstrate that UV/BD is a promising approach for the treatment of Cr(VI)-laden wastewater. The findings here also suggest that utilization of diketones in redox conversion of contaminants is a topic deserving further research.
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Affiliation(s)
- Bingdang Wu
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, 210023, China
| | - Li Zhang
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, 210023, China
| | - Shijie Wei
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, 210023, China
| | - Lixue Ou'Yang
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, 210023, China
| | - Ran Yin
- Department of Civil and Environmental Engineering, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong
| | - Shujuan Zhang
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, 210023, China.
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8
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Jin J, Chen Z, Song X, Wu B, Zhang G, Zhang S. Effects of acetylacetone on the thermal and photochemical conversion of benzoquinone in aqueous solution. CHEMOSPHERE 2019; 223:628-635. [PMID: 30798058 DOI: 10.1016/j.chemosphere.2019.02.080] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2018] [Revised: 01/08/2019] [Accepted: 02/13/2019] [Indexed: 06/09/2023]
Abstract
Quinones are components of electron transport chains in photosynthesis and respiration. Acetylacetone (AA), structurally similar to benzoquinone (BQ) for the presence of two identical carbonyl groups, has been reported as a quinone-like electron shuttle. Both BQ and AA are important chemicals in the aquatic environment. However, little information is known about their interactions if co-existed. We found here that AA significantly enhanced the conversion of BQ. By analyzing the evolution of chemical concentration, solution pH, dissolved oxygen, and the final products, the interactions between AA and BQ were elucidated. The reactions between BQ and AA generated oxygen but ultimately led to the reduction of solution pH and dissolved oxygen. The reactions proceeded faster under indoor lighting condition than in the dark. The formation of semiquinone radicals is believed as the primary step. The secondary AA-derived radicals might be strongly oxidative or reductive, depending on the concentration of dissolved oxygen. Insoluble humus was generated in the mixture of BQ and AA. These results suggest that the presence of AA might interfere with photosynthesis and respiration through the interactions with quinones.
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Affiliation(s)
- Jiyuan Jin
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, 210023, China
| | - Zhihao Chen
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, 210023, China
| | - Xiaojie Song
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, 210023, China
| | - Bingdang Wu
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, 210023, China
| | - Guoyang Zhang
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, 210023, China
| | - Shujuan Zhang
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, 210023, China.
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9
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Sebbar N, Bozzelli JW, Bockhorn H. Comparison of RC( O) OOH, RC( O)O OH and R(C O)OO H bond dissociation energies with RC OOH, RCO OH and RCOO H, R as phenyl, vinyl and alkyl groups. Chem Phys Lett 2015. [DOI: 10.1016/j.cplett.2015.03.040] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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10
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Groß CBM, Dillon TJ, Crowley JN. Pressure dependent OH yields in the reactions of CH3CO and HOCH2CO with O2. Phys Chem Chem Phys 2014; 16:10990-8. [DOI: 10.1039/c4cp01108b] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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11
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Auzmendi-Murua I, Bozzelli JW. Thermochemistry, Reaction Paths, and Kinetics on the Secondary Isooctane Radical Reaction with 3
O2. INT J CHEM KINET 2013. [DOI: 10.1002/kin.20825] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Itsaso Auzmendi-Murua
- Department of Chemistry and Chemical Engineering; New Jersey Institute of Technology; Newark NJ 07102
| | - Joseph W. Bozzelli
- Department of Chemistry and Chemical Engineering; New Jersey Institute of Technology; Newark NJ 07102
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12
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Allen JW, Goldsmith CF, Green WH. Automatic estimation of pressure-dependent rate coefficients. Phys Chem Chem Phys 2012; 14:1131-55. [DOI: 10.1039/c1cp22765c] [Citation(s) in RCA: 85] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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13
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Sebbar N, Bozzelli JW, Bockhorn H. Thermochemistry and Reaction Paths in the Oxidation Reaction of Benzoyl Radical: C6H5C•(═O). J Phys Chem A 2011; 115:11897-914. [DOI: 10.1021/jp2078067] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Nadia Sebbar
- Karlsruhe Institute of Technology, Engler-Bunte-Institut, Karlsruhe, Germany
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14
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Carr SA, Glowacki DR, Liang CH, Baeza-Romero MT, Blitz MA, Pilling MJ, Seakins PW. Experimental and Modeling Studies of the Pressure and Temperature Dependences of the Kinetics and the OH Yields in the Acetyl + O2 Reaction. J Phys Chem A 2011; 115:1069-85. [DOI: 10.1021/jp1099199] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Scott A. Carr
- School of Chemistry and ‡School of Earth and Environment, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - David R. Glowacki
- School of Chemistry and ‡School of Earth and Environment, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Chi-Hsiu Liang
- School of Chemistry and ‡School of Earth and Environment, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - M. Teresa Baeza-Romero
- School of Chemistry and ‡School of Earth and Environment, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Mark A. Blitz
- School of Chemistry and ‡School of Earth and Environment, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Michael J. Pilling
- School of Chemistry and ‡School of Earth and Environment, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Paul W. Seakins
- School of Chemistry and ‡School of Earth and Environment, University of Leeds, Leeds LS2 9JT, United Kingdom
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15
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Chen SY, Lee YP. Transient infrared absorption of t-CH3C(O)OO, c-CH3C(O)OO, and alpha-lactone recorded in gaseous reactions of CH3CO and O2. J Chem Phys 2010; 132:114303. [PMID: 20331293 DOI: 10.1063/1.3352315] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
A step-scan Fourier-transform infrared spectrometer coupled with a multipass absorption cell was utilized to monitor the transient species produced in gaseous reactions of CH(3)CO and O(2); IR absorption spectra of CH(3)C(O)OO and alpha-lactone were observed. Absorption bands with origins at 1851+/-1, 1372+/-2, 1169+/-6, and 1102+/-3 cm(-1) are attributed to t-CH(3)C(O)OO, and those at 1862+/-3, 1142+/-4, and 1078+/-6 cm(-1) are assigned to c-CH(3)C(O)OO. A weak band near 1960 cm(-1) is assigned to alpha-lactone, cyc-CH(2)C(=O)O, a coproduct of OH. These observed rotational contours agree satisfactorily with simulated bands based on predicted rotational parameters and dipole derivatives, and observed vibrational wavenumbers agree with harmonic vibrational wavenumbers predicted with B3LYP/aug-cc-pVDZ density-functional theory. The observed relative intensities indicate that t-CH(3)C(O)OO is more stable than c-CH(3)C(O)OO by 3+/-2 kJ mol(-1). Based on these observations, the branching ratio for the OH+alpha-lactone channel of the CH(3)CO+O(2) reaction is estimated to be 0.04+/-0.01 under 100 Torr of O(2) at 298 K. A simple kinetic model is employed to account for the decay of CH(3)C(O)OO.
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Affiliation(s)
- Sun-Yang Chen
- Department of Applied Chemistry, National Chiao Tung University, Hsinchu 30010, Taiwan
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16
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da Silva G, Cole JA, Bozzelli JW. Kinetics of the Cyclopentadienyl + Acetylene, Fulvenallene + H, and 1-Ethynylcyclopentadiene + H Reactions. J Phys Chem A 2010; 114:2275-83. [DOI: 10.1021/jp906835w] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Gabriel da Silva
- Department of Chemical and Biomolecular Engineering, The University of Melbourne, Victoria 3010, Australia, and Department of Chemistry and Environmental Science, New Jersey Institute of Technology, Newark, New Jersey 07102
| | - John A. Cole
- Department of Chemical and Biomolecular Engineering, The University of Melbourne, Victoria 3010, Australia, and Department of Chemistry and Environmental Science, New Jersey Institute of Technology, Newark, New Jersey 07102
| | - Joseph W. Bozzelli
- Department of Chemical and Biomolecular Engineering, The University of Melbourne, Victoria 3010, Australia, and Department of Chemistry and Environmental Science, New Jersey Institute of Technology, Newark, New Jersey 07102
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17
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Carr SA, Baeza-Romero MT, Blitz MA, Pilling MJ, Heard DE, Seakins PW. OH yields from the CH3CO+O2 reaction using an internal standard. Chem Phys Lett 2007. [DOI: 10.1016/j.cplett.2007.07.099] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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da Silva G, Chen CC, Bozzelli JW. Toluene Combustion: Reaction Paths, Thermochemical Properties, and Kinetic Analysis for the Methylphenyl Radical + O2 Reaction. J Phys Chem A 2007; 111:8663-76. [PMID: 17696501 DOI: 10.1021/jp068640x] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Aromatic compounds such as toluene and xylene are major components of many fuels. Accurate kinetic mechanisms for the combustion of toluene are, however, incomplete, as they do not accurately model experimental results such as strain rates and ignition times and consistently underpredict conversion. Current kinetic mechanisms for toluene combustion neglect the reactions of the methylphenyl radicals, and we believe that this is responsible, in part, for the shortcomings of these models. We also demonstrate how methylphenyl radical formation is important in the combustion and pyrolysis of other alkyl-substituted aromatic compounds such as xylene and trimethylbenzene. We have studied the oxidation reactions of the methylphenyl radicals with O2 using computational ab initio and density functional theory methods. A detailed reaction submechanism is presented for the 2-methylphenyl radical + O2 system, with 16 intermediates and products. For each species, enthalpies of formation are calculated using the computational methods G3 and G3B3, with isodesmic work reactions used to minimize computational errors. Transition states are calculated at the G3B3 level, yielding high-pressure limit elementary rate constants as a function of temperature. For the barrierless methylphenyl + O2 and methylphenoxy + O association reactions, rate constants are determined from variational transition state theory. Multichannel, multifrequency quantum Rice-Ramsperger-Kassel (qRRK) theory, with master equation analysis for falloff, provides rate constants as a function of temperature and pressure from 800 to 2400 K and 1 x 10(-4) to 1 x 10(3) atm. Analysis of our results shows that the dominant pathways for reaction of the three isomeric methylphenyl radicals is formation of methyloxepinoxy radicals and subsequent ring opening to methyl-dioxo-hexadienyl radicals. The next most important reaction pathway involves formation of methylphenoxy radicals + O in a chain branching process. At lower temperatures, the formation of stabilized methylphenylperoxy radicals becomes significant. A further important reaction channel is available only to the 2-methylphenyl isomer, where 6-methylene-2,4-cyclohexadiene-1-one (ortho-quinone methide, o-QM) is produced via an intramolecular hydrogen transfer from the methyl group to the peroxy radical in 2-methylphenylperoxy, with subsequent loss of OH. The decomposition of o-QM to benzene + CO reveals a potentially important new pathway for the conversion of toluene to benzene during combustion. A number of the important products of toluene combustion proposed in this study are known to be precursors of polyaromatic hydrocarbons that are involved in soot formation. Reactions leading to the important unsaturated oxygenated intermediates identified in this study, and the further reactions of these intermediates, are not included in current aromatic oxidation mechanisms.
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Affiliation(s)
- Gabriel da Silva
- Department of Chemistry and Environmental Science, New Jersey Institute of Technology, Newark, New Jersey 07102, USA
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19
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Kovács G, Zádor J, Farkas E, Nádasdi R, Szilágyi I, Dóbé S, Bérces T, Márta F, Lendvay G. Kinetics and mechanism of the reactions of CH3CO and CH3C(O)CH2 radicals with O2. Low-pressure discharge flow experiments and quantum chemical computations. Phys Chem Chem Phys 2007; 9:4142-54. [PMID: 17687464 DOI: 10.1039/b706216h] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The reactions CH(3)CO + O(2)--> products (1), CH(3)CO + O(2)--> OH +other products (1b) and CH(3)C(O)CH(2) + O(2)--> products (2) have been studied in isothermal discharge flow reactors with laser induced fluorescence monitoring of OH and CH(3)C(O)CH(2) radicals. The experiments have been performed at overall pressures between 1.33 and 10.91 mbar of helium and 298 +/- 1 K reaction temperature. OH formation has been found to be the dominant reaction channel for CH(3)CO + O(2): the branching ratio, Gamma(1b) = k(1b)/k(1), is close to unity at around 1 mbar, but decreases rapidly with increasing pressure. The rate constant of the overall reaction, k(2), has been found to be pressure dependent: the fall-off behaviour has been analysed in comparison with reported data. Electronic structure calculations have confirmed that at room temperature the reaction of CH(3)C(O)CH(2) with O(2) is essentially a recombination-type process. At high temperatures, the further reactions of the acetonyl-peroxyl adduct may yield OH radicals, but the most probable channel seems to be the O(2)-catalysed keto-enol transformation of acetonyl. Implications of the results for atmospheric modelling studies have been discussed.
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Affiliation(s)
- Gergely Kovács
- Chemical Research Center, Hungarian Academy of Sciences, Pusztaszeri út 59-67, H-1025 Budapest, Hungary
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20
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Maranzana A, Barker JR, Tonachini G. Master equation simulations of competing unimolecular and bimolecular reactions: application to OH production in the reaction of acetyl radical with O2. Phys Chem Chem Phys 2007; 9:4129-41. [PMID: 17687463 DOI: 10.1039/b705116f] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Master equation calculations were carried out to simulate the production of hydroxyl free radicals initiated by the reaction of acetyl free radicals (CH3(C=O).) with molecular oxygen. In particular, the competition between the unimolecular reactions and bimolecular reactions of vibrationally excited intermediates was modeled by using a single master equation. The vibrationally excited intermediates (isomers of acetylperoxyl radicals) result from the initial reaction of acetyl free radical with O2. The bimolecular reactions were modeled using a novel pseudo-first-order microcanonical rate constant approach. Stationary points on the multi-well, multi-channel potential energy surface (PES) were calculated at the DFT(B3LYP)/6-311G(2df,p) level of theory. Some additional calculations were carried out at the CASPT2(7,5)/6-31G(d) level of theory to investigate barrierless reactions and other features of the PES. The master equation simulations are in excellent agreement with the experimental OH yields measured in N2 or He buffer gas near 300 K, but they do not explain a recent report that the OH yields are independent of pressure in nearly pure O2 buffer gas.
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Affiliation(s)
- Andrea Maranzana
- Department of Atmospheric, Oceanic and Space Sciences, University of Michigan, 2455 Hayward Street, Ann Arbor, MI 48109-2143, USA
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21
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da Silva G, Bozzelli JW. Enthalpies of Formation, Bond Dissociation Energies, and Molecular Structures of the n-Aldehydes (Acetaldehyde, Propanal, Butanal, Pentanal, Hexanal, and Heptanal) and Their Radicals. J Phys Chem A 2006; 110:13058-67. [PMID: 17134166 DOI: 10.1021/jp063772b] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Aldehydes are important intermediates and products in a variety of combustion and gas-phase oxidation processes, such as in low-temperature combustion, in the atmosphere, and in interstellar media. Despite their importance, the enthalpies of formation and bond dissociation energies (BDEs) for the aldehydes are not accurately known. We have determined enthalpies of formation for acetaldehyde, propanal, and butanal from thermodynamic cycles, using experimentally measured reaction and formation enthalpies. All enthalpy values used for reference molecules and reactions were first verified to be accurate to within around 1 kcal mol-1 using high-level ab initio calculations. Enthalpies of formation were found to be -39.72 +/- 0.16 kcal mol-1 for acetaldehyde, -45.18 +/- 1.1 kcal mol-1 for propanal, and -49.27 +/- 0.16 kcal mol-1 for butanal. Enthalpies of formation for these three aldehydes, as well as for pentanal, hexanal, and heptanal, were calculated using the G3, G3B3, and CBS-APNO theoretical methods, in conjunction with bond-isodesmic work reactions. On the basis of the results of our thermodynamic cycles, theoretical calculations using isodesmic work reactions, and existing experimental measurements, we suggest that the best available formation enthalpies for the aldehydes acetaldehyde, propanal, butanal, pentanal, hexanal, and heptanal are -39.72, -45.18, -50.0, -54.61, -59.37, and -64.2 kcal mol-1, respectively. Our calculations also identify that the literature enthalpy of formation of crotonaldehyde is in error by as much as 1 kcal mol-1, and we suggest a value of -25.1 kcal mol-1, which we calculate using isodesmic work reactions. Bond energies for each of the bonds in the aldehydes up to pentanal were calculated at the CBS-APNO level. Analysis of the BDEs reveals the R-CH(2)CH=O to be the weakest bond in all aldehydes larger than acetaldehyde, due to formation of the resonantly stabilized vinoxy radical (vinyloxy radical/formyl methyl radical). It is proposed that the vinoxy radical as well as the more commonly considered formyl and acetyl radicals are important products of aldehyde combustion and oxidation, and the reaction pathways of the vinoxy, formyl, and acetyl radicals are discussed. Group additivity values for the carbon-oxygen-hydrogen groups common to the aldehydes are also determined. Internal rotor profiles and electrostatic potential surfaces are used to study the dipole induced dipole-dipole interaction in the synperiplanar conformation of propanal. It is proposed that the loss of this dipole-dipole interaction in RC(.-)HCH(2)CH=O radicals causes a ca. 1-2 kcal mol-1 decrease in the aldehyde C-H and C-C bond energies corresponding to RC(.-)HCH(2)CH=O radical formation.
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Affiliation(s)
- Gabriel da Silva
- Department of Chemistry and Environmental Science, New Jersey Institute of Technology, Newark, New Jersey 07102, USA
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22
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Bäcktorp C, Wass JRTJ, Panas I, Sköld M, Börje A, Nyman G. Theoretical Investigation of Linalool Oxidation. J Phys Chem A 2006; 110:12204-12. [PMID: 17078616 DOI: 10.1021/jp0603278] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
This study concerns the autoxidation of one of the most used fragrances in daily life, linalool (3,7-dimethyl-1,6-octadien-3-ol). It reacts with O2 to form hydroperoxides, which are known to be important contact allergens. Pathways for hydroperoxide formation are investigated by means of quantum mechanical electronic structure calculations. Optimized molecular geometries and harmonic vibrational frequencies are determined using density functional theory (DFT). Insight into how the addition of O2 to linalool occurs is obtained by establishing a theoretical framework and systematically investigating three smaller systems: propene, 2-methyl-2-butene, and 2-methyl-2-pentene. 2-Methyl-2-pentene was chosen as a model system and used to compare with linalool. This theoretical study characterizes the linalool-O2 biradical intermediate state, which constitutes a branching point for the further oxidation reactions pathways. Thus, the observed linalool oxidation product spectrum is discussed in terms of a direct reaction path, the ene-type mechanism, and the radical mechanism. The major hydroperoxide found in experiments is 7-hydroperoxy-3,7-dimethyl-octa-1,5-diene-3-ol, and the calculated results support this finding.
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Affiliation(s)
- Carina Bäcktorp
- Department of Chemistry, Physical Chemistry, Electrochemistry, Dermatochemistry and Skin Allergy, Göteborg University, SE-412 96 Göteborg, Sweden.
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23
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Le Crâne JP, Rayez MT, Rayez JC, Villenave E. A reinvestigation of the kinetics and the mechanism of the CH3C(O)O2 + HO2 reaction using both experimental and theoretical approaches. Phys Chem Chem Phys 2006; 8:2163-71. [PMID: 16751874 DOI: 10.1039/b518321a] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The kinetics and the mechanism of the reaction CH(3)C(O)O(2)+ HO(2) were reinvestigated at room temperature using two complementary approaches: one experimental, using flash photolysis/UV absorption technique and one theoretical, with quantum chemistry calculations performed using the density functional theory (DFT) method with the three-parameter hybrid functional B3LYP associated with the 6-31G(d,p) basis set. According to a recent paper reported by Hasson et al., [J. Phys. Chem., 2004, 108, 5979-5989] this reaction may proceed by three different channels: CH(3)C(O)O(2)+ HO(2)--> CH(3)C(O)OOH + O(2) (1a); CH(3)C(O)O(2)+ HO(2)--> CH(3)C(O)OH + O(3) (1b); CH(3)C(O)O(2)+ HO(2)--> CH(3)C(O)O + OH + O(2) (1c). In experiments, CH(3)C(O)O(2) and HO(2) radicals were generated using Cl-initiated oxidation of acetaldehyde and methanol, respectively, in the presence of oxygen. The addition of amounts of benzene in the system, forming hydroxycyclohexadienyl radicals in the presence of OH, allowed us to answer that channel (1c) is <10%. The rate constant k(1) of reaction (1) has been finally measured at (1.50 +/- 0.08) x 10(-11) cm(3) molecule(-1) s(-1) at 298 K, after having considered the combination of all the possible values for the branching ratios k(1a)/k(1,)k(1b)/k(1,)k(1c)/k(1) and has been compared to previous measurements. The branching ratio k(1b)/k(1), determined by measuring ozone in situ, was found to be equal to (20 +/- 1)%, a value consistent with the previous values reported in the literature. DFT calculations show that channel (1c) is also of minor importance: it was deduced unambiguously that the formation of CH(3)C(O)OOH + O(2) (X (3)Sigma(-)(g)) is the dominant product channel, followed by the second channel (1b) leading to CH(3)C(O)OH and singlet O(3) and, much less importantly, channel (1c) which corresponds to OH formation. These conclusions give a reliable explanation of the experimental observations of this work. In conclusion, the present study demonstrates that the CH(3)C(O)O(2)+ HO(2) is still predominantly a radical chain termination reaction in the tropospheric ozone chain formation processes.
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Affiliation(s)
- Jean-Paul Le Crâne
- Laboratoire de Physico-Chimie Moléculaire, CNRS UMR 5803, Université Bordeaux I, 33405, Talence Cedex, France.
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24
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Devolder P, Dusanter S, Lemoine B, Fittschen C. About the co-product of the OH radical in the reaction of acetyl with O2 below atmospheric pressure. Chem Phys Lett 2006. [DOI: 10.1016/j.cplett.2005.09.114] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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25
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Hou H, Li A, Hu H, Li Y, Li H, Wang B. Mechanistic and kinetic study of the CH3CO+O2 reaction. J Chem Phys 2005; 122:224304. [PMID: 15974665 DOI: 10.1063/1.1897375] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Potential-energy surface of the CH3CO + O2 reaction has been calculated by ab initio quantum chemistry methods. The geometries were optimized using the second-order Moller-Plesset theory (MP2) with the 6-311G(d,p) basis set and the coupled-cluster theory with single and double excitations (CCSD) with the correlation consistent polarized valence double zeta (cc-pVDZ) basis set. The relative energies were calculated using the Gaussian-3 second-order Moller-Plesset theory with the CCSD/cc-pVDZ geometries. Multireference self-consistent-field and MP2 methods were also employed using the 6-311G(d,p) and 6-311++G(3df,2p) basis sets. Both addition/elimination and direct abstraction mechanisms have been investigated. It was revealed that acetylperoxy radical [CH3C(O)OO] is the initial adduct and the formation of OH and alpha-lactone [CH2CO2(1A')] is the only energetically accessible decomposition channel. The other channels, e.g., abstraction, HO2 + CH2CO, O + CH3CO2, CO + CH3O2, and CO2 + CH3O, are negligible. Multichannel Rice-Ramsperger-Kassel-Marcus theory and transition state theory (E-resolved) were employed to calculate the overall and individual rate coefficients and the temperature and pressure dependences. Fairly good agreement between theory and experiments has been obtained without any adjustable parameters. It was concluded that at pressures below 3 Torr, OH and CH2CO2(1A') are the major nascent products of the oxidation of acetyl radicals, although CH2CO2(1A') might either undergo unimolecular decomposition to form the final products of CH2O + CO or react with OH and Cl to generate H2O and HCl. The acetylperoxy radicals formed by collisional stabilization are the major products at the elevated pressures. In atmosphere, the yield of acetylperoxy is nearly unity and the contribution of OH is only marginal.
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Affiliation(s)
- Hua Hou
- College of Chemistry and Molecular Sciences, Wuhan University, Wuhan, 430072, People's Republic of China
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26
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Hermans I, Nguyen TL, Jacobs PA, Peeters J. Autoxidation of Cyclohexane: Conventional Views Challenged by Theory and Experiment. Chemphyschem 2005; 6:637-45. [PMID: 15881579 DOI: 10.1002/cphc.200400211] [Citation(s) in RCA: 106] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
In spite of its industrial importance, the detailed reaction mechanism of cyclohexane autoxidation by O2 is still insufficiently known. Based on quantum chemical potential energy surfaces, rate coefficients of the primary and secondary chain propagation steps involving the cyclohexylperoxyl (CyOO) radical were evaluated using multiconformer transition-state theory. Including tunneling and hindered-internal-rotation effects, the rate coefficient for hydrogen-atom abstraction from cyclohexane (CyH) by CyOO was calculated to be k(T)= 1.46 x 10(-11) x exp(-17.8 kcal mol(-1)/ RT) cm3s(-1) (300-600K), close to the experimental data. A "Franck-Rabinowitch cage" reaction between the nascent cyclohexylhydroperoxide (CyOOH) and cyclohexyl radical, products from CyOO + CyH, is put forward as an initially important cyclohexanol (CyOH) formation channel. alphaH abstraction by CyOO. from cyclohexanone was calculated to be only about five times faster than that from CyH, too slow to explain all the observed side products. The a-hydrogen (alphaH) abstractions from CyOH and CyOOH by CyOO. are predicted to be about 10 and 40 times faster, respectively, than the CyOO. +CyH reaction. The very fast CyOO.+CyOOH reaction proceeds through the unstable Cy-alphaH .OOH radical that decomposes spontaneously into the ketone (Q=O) plus the OH radical; the "hot" .OH is found to produce the bulk of the alcohol via a second, "activated cage" reaction analogous to that above. It is thus shown how the very reactive CyOOH intermediate is the predominant source of ketone and alcohol, while it also leads to some side products. The alpha-hydroxycyclohexylperoxyl radical formed during the moderately fast oxidation of CyOH is shown to decompose fast into HO2 + cyclohexanone in a rapidly equilibrated reaction, which constitutes a smaller, second ketone source. These two fast cyclohexanone forming routes avoid the need for unfavorable molecular routes hitherto invoked as ketone sources. The theoretical predictions are supported and complemented by experimental findings. The newly proposed scheme is also largely applicable to the oxidation of other hydrocarbons, such as toluene, xylene, and ethylbenzene.
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Affiliation(s)
- Ive Hermans
- Department of Chemistry, KULeuven Celestijnenlaan 200F, 3001 Heverlee (Belgium).
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27
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Sebbarand N, Bockhorn H, Bozzelli JW. Thermochemical Properties, Rotation Barriers, and Group Additivity for Unsaturated Oxygenated Hydrocarbons and Radicals Resulting from Reaction of Vinyl and Phenyl Radical Systems with O2. J Phys Chem A 2005; 109:2233-53. [PMID: 16838995 DOI: 10.1021/jp046285+] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Oxidation of unsaturated and aromatic hydrocarbons in atmospheric and combustion processes results in formation of linear and cyclic unsaturated, oxygenated-hydrocarbon intermediates. The thermochemical parameters delatafH degrees 298, S degrees 298, and C(p)(f298)(T) for these intermediates are needed to understand their stability and reaction paths in further oxidation. These properties are not available for a majority of these unsaturated oxy-hydrocarbons and their corresponding radicals, even via group additivity methods. Enthalpy, entropy, and heat capacity of a series of 40 oxygenated and non-oxygenated molecules, or radicals corresponding to hydrogen atom loss from the parent stable molecules are determined in this study. Enthalpy (delatafH degrees 298 in kcal mol(-1)) is derived from the density function calculations at the B3LYP/6-311g(d,p) calculated enthalpy of reaction (delatafH degrees rxn,298) and by use of isodesmic (work) reactions. Estimation of error in enthalpy delatafH degrees 298, from use of computational chemistry coupled with work reactions analysis, is presented using comparisons between the calculated and literature enthalpies of reaction. Entropies (S degrees 298) and heat capacities (C(p)(f298)(T)) were calculated using the B3LYP/6-311G(d,p) determined frequencies and geometries. Potential barriers for internal rotors in each molecule were determined and used (in place of torsion frequencies) to calculate contributions to S and C(p)(T) from the hindered rotors. Twenty-six groups for use in group additivity (GA) are also developed.
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Affiliation(s)
- Nadia Sebbarand
- Institut für Technische Chemie and Polymerchemie, Universität Karlsruhe (TH), Kaiserstrasse 12, 76128 Karlsruhe, Germany
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28
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Sebbar N, Bozzelli JW, Bockhorn H. Enthalpy of formation and bond energies on unsaturated oxygenated hydrocarbons using G3MP2B3 calculation methods. INT J CHEM KINET 2005. [DOI: 10.1002/kin.20086] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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29
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Butkovskaya NI, Kukui A, Le Bras G. Branching Fractions for H2O Forming Channels of the Reaction of OH Radicals with Acetaldehyde. J Phys Chem A 2004. [DOI: 10.1021/jp036740m] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- N. I. Butkovskaya
- CNRS, Laboratoire de Combustion et Systèmes Réactifs, 1C Av. de la Recherche Scientifique, 45071 Orléans Cedex 2, France and CNRS, Service d'Aéronomie, Paris, France
| | - A. Kukui
- CNRS, Laboratoire de Combustion et Systèmes Réactifs, 1C Av. de la Recherche Scientifique, 45071 Orléans Cedex 2, France and CNRS, Service d'Aéronomie, Paris, France
| | - G. Le Bras
- CNRS, Laboratoire de Combustion et Systèmes Réactifs, 1C Av. de la Recherche Scientifique, 45071 Orléans Cedex 2, France and CNRS, Service d'Aéronomie, Paris, France
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30
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Zalyubovsky SJ, Glover BG, Miller TA. Cavity Ringdown Spectroscopy of the à − X̃ Electronic Transition of the CH3C(O)O2 Radical. J Phys Chem A 2003. [DOI: 10.1021/jp0305279] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Sergey J. Zalyubovsky
- Laser Spectroscopy Facility, Department of Chemistry, The Ohio State University, 120 W. 18th Avenue, Columbus, Ohio 43210
| | - Brent G. Glover
- Laser Spectroscopy Facility, Department of Chemistry, The Ohio State University, 120 W. 18th Avenue, Columbus, Ohio 43210
| | - Terry A. Miller
- Laser Spectroscopy Facility, Department of Chemistry, The Ohio State University, 120 W. 18th Avenue, Columbus, Ohio 43210
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31
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Lee J, Bozzelli JW. Thermochemical and Kinetic Analysis of the Formyl Methyl Radical + O2 Reaction System. J Phys Chem A 2003. [DOI: 10.1021/jp030001o] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Affiliation(s)
- Jongwoo Lee
- Department of Chemical Engineering and Chemistry, New Jersey Institute of Technology, Newark, New Jersey 07102
| | - Joseph W. Bozzelli
- Department of Chemical Engineering and Chemistry, New Jersey Institute of Technology, Newark, New Jersey 07102
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