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Xu Q, Zhang J, Liu B, Wang H, Xu G, Gao J, Wang Z, Guan J. Probing the Reaction of Propargyl Radical with Molecular Oxygen by Synchrotron VUV Photoionization Mass Spectrometry. J Phys Chem A 2024; 128:7105-7113. [PMID: 39151122 DOI: 10.1021/acs.jpca.4c03294] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/18/2024]
Abstract
Self-reaction of propargyl (C3H3) radical is the main pathway to benzene, the formation of which is the rate-controlling step toward the formation of polycyclic aromatic hydrocarbons (PAHs) and soot. Oxidation of C3H3 is a promising strategy to inhibit the formation of hazardous PAHs and soot. In the present study, we studied the C3H3 + O2 reaction from 650 to 1100 K in a laminar flow reactor and identified the intermediates and products by synchrotron VUV photoionization mass spectrometry. 2-Propynal, ethenone, formaldehyde, CO, CO2, C2H2, C2H4, and C3O2 were identified. Among them, 2-propynal, ethenone, and formaldehyde provided direct evidence for the branching reaction of C3H3 + O2 → HCCCHO + OH, C3H3 + O2 → H2CCO + CHO, and C3H3 + O2 → H2CO + CHCO, respectively. Potential energy surface calculation and mechanistic analysis of the C3O2 formations implied that C3H3 + O2 → CCCHO + H2O and C3H3 + O2 → HCCCO + H2O could occur, despite lacking direct observations of CCCHO and HCCCO radicals. The formation of ethenone and CO suggested the occurrence of the two CO elimination channels. We incorporated these validated reactions and the corresponding rate coefficients in the kinetic model of NUIGMech1.3, and the simulation showed obvious improvements toward the measured mole fractions of C3H3 and H2CCO, suggesting that the new C3H3 + O2 reaction channels were crucial in the overall combustion modeling of the important intermediate propyne (C3H4).
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Affiliation(s)
- Qiang Xu
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230029, Anhui, P. R. China
| | - Jinyang Zhang
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230029, Anhui, P. R. China
| | - Bingzhi Liu
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230029, Anhui, P. R. China
| | - Hong Wang
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230029, Anhui, P. R. China
| | - Guangxian Xu
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230029, Anhui, P. R. China
| | - Jiao Gao
- School of Pharmacy, Anhui Medical College, Hefei 230601, Anhui, P. R. China
| | - Zhandong Wang
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230029, Anhui, P. R. China
- State Key Laboratory of Fire Science, University of Science and Technology of China, Hefei 230026, Anhui, P. R. China
| | - Jiwen Guan
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230029, Anhui, P. R. China
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2
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Nixon CA. The Composition and Chemistry of Titan's Atmosphere. ACS EARTH & SPACE CHEMISTRY 2024; 8:406-456. [PMID: 38533193 PMCID: PMC10961852 DOI: 10.1021/acsearthspacechem.2c00041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Revised: 11/02/2023] [Accepted: 02/02/2024] [Indexed: 03/28/2024]
Abstract
In this review I summarize the current state of knowledge about the composition of Titan's atmosphere and our current understanding of the suggested chemistry that leads to that observed composition. I begin with our present knowledge of the atmospheric composition, garnered from a variety of measurements including Cassini-Huygens, the Atacama Large Millimeter/submillimeter Array, and other ground- and space-based telescopes. This review focuses on the typical vertical profiles of gases at low latitudes rather than global and temporal variations. The main body of the review presents a chemical description of how complex molecules are believed to arise from simpler species, considering all known "stable" molecules-those that have been uniquely identified in the neutral atmosphere. The last section of the review is devoted to the gaps in our present knowledge of Titan's chemical composition and how further work may fill those gaps.
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Affiliation(s)
- Conor A. Nixon
- Planetary Systems Laboratory, NASA Goddard Space Flight Center, 8800 Greenbelt Road, Greenbelt, Maryland 20771, United
States
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3
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Zhao L, Lu W, Ahmed M, Zagidullin MV, Azyazov VN, Morozov AN, Mebel AM, Kaiser RI. Gas-phase synthesis of benzene via the propargyl radical self-reaction. SCIENCE ADVANCES 2021; 7:7/21/eabf0360. [PMID: 34020951 PMCID: PMC8139581 DOI: 10.1126/sciadv.abf0360] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Accepted: 03/31/2021] [Indexed: 06/01/2023]
Abstract
Polycyclic aromatic hydrocarbons (PAHs) have been invoked in fundamental molecular mass growth processes in our galaxy. We provide compelling evidence of the formation of the very first ringed aromatic and building block of PAHs-benzene-via the self-recombination of two resonantly stabilized propargyl (C3H3) radicals in dilute environments using isomer-selective synchrotron-based mass spectrometry coupled to theoretical calculations. Along with benzene, three other structural isomers (1,5-hexadiyne, fulvene, and 2-ethynyl-1,3-butadiene) and o-benzyne are detected, and their branching ratios are quantified experimentally and verified with the aid of computational fluid dynamics and kinetic simulations. These results uncover molecular growth pathways not only in interstellar, circumstellar, and solar systems environments but also in combustion systems, which help us gain a better understanding of the hydrocarbon chemistry of our universe.
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Affiliation(s)
- Long Zhao
- Department of Chemistry, University of Hawaii at Manoa, Honolulu, HI 96822, USA
| | - Wenchao Lu
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Musahid Ahmed
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.
| | | | - Valeriy N Azyazov
- Lebedev Physical Institute, Samara 443011, Russian Federation
- Samara National Research University, Samara 443086, Russian Federation
| | - Alexander N Morozov
- Department of Chemistry and Biochemistry, Florida International University, Miami, FL 33199, USA
| | - Alexander M Mebel
- Department of Chemistry and Biochemistry, Florida International University, Miami, FL 33199, USA.
| | - Ralf I Kaiser
- Department of Chemistry, University of Hawaii at Manoa, Honolulu, HI 96822, USA.
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4
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Pham TV, Tue Trang HT. Combination Reactions of Propargyl Radical with Hydroxyl Radical and the Isomerization and Dissociation of trans-Propenal. J Phys Chem A 2020; 124:6144-6157. [PMID: 32634312 DOI: 10.1021/acs.jpca.0c05106] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Ab initio investigation for the ground-electronic potential energy surface (PES) of the CH2CCH + OH combination and the trans-CH2CHCHO isomerization and decomposition has been performed at the UCCSD(T)/CBS(TQ5)//M06-2X/aug-cc-pVTZ level of theory. Thermal and microcanonical rate constants, as well as branching ratios in the 300-2000 K temperature range have been predicted based on optimized structures and vibrational frequencies of species involved using statistical theoretical VRC-TST and RRKM master equation computations. The calculated results are in good agreement with the prior reported data, particularly as an accurate scaling of the energy barriers was carried out. Based on the view of PES and kinetic-predicted values, the reaction paths leading to C2H2 + CO + H2, CH3CH + CO, C2H4 + CO, C2H3 + HCO, and C3H3O + H are the prevailing product channels for the C3H3 + OH bimolecular reaction under the considered 300-2000 K temperature range. Among those products, CH3CH + CO is the most dominant one in the low-temperature condition; however, C2H2 + CO + H2 becomes the most favorable product in the high-temperature region. Alternatively, the C3H4O dissociation processes leading to C2H2 + CO + H2, C2H3 + HCO, C2H4 + CO, and CH2C + CH2O constitute the major paths, in which, C2H2 + CO + H2 is the most critical one with the ∼62% and ∼59% branching ratios at E = 148 and 182 kcal/mol, respectively. The overall second-order rate constants of the bimolecular reaction C3H3 + OH → products obtained at the pressure 760 Torr (Ar) can be illustrated by the modified Arrhenius expression of k(T) = 1.36 × 10-13T1.26 exp[(-1.12 ± 0.43 kcal mol-1)/RT] and/or k(T) = 3.77 × 1017T-7.58 exp[(-18.82 ± 0.20 kcal mol-1)/RT] cm3 molecule-1 s-1, covering the temperature range of 300-1300 and/or 1300-2000 K, respectively. The total high-pressure limit rate constant for the C3H3 + OH → CH2CCHOH barrierless processes is in good agreement with the k(T) = 8.30 × 10-10 T-0.1 cm3 molecule-1 s-1 literature data. Moreover, microcanonical rate constants for the C3H4O isomerization and dissociation are in excellent accordance with the previously predicted values given by Chin and Lee. The present study supplies a thorough insight into the mechanisms and kinetics of the C3H3 + OH combination as well as the C3H4O multistep isomerization/dissociation pathways.
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Affiliation(s)
- Tien V Pham
- School of Chemical Engineering, Hanoi University of Science and Technology, Hanoi, Vietnam
| | - Hoang T Tue Trang
- Department of Chemistry, Hanoi Architectural University, Hanoi, Vietnam
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5
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Colazzo L, Casarin M, Sambi M, Sedona F. On-Surface Photochemistry of Pre-Ordered 1-Methyl-2-phenyl-acetylenes: C-H Bond Activation and Intermolecular Coupling on Highly Oriented Pyrolytic Graphite. Chemphyschem 2019; 20:2317-2321. [PMID: 31245897 DOI: 10.1002/cphc.201900382] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Revised: 06/03/2019] [Indexed: 11/08/2022]
Abstract
In this contribution we report on light-induced metal-free coupling of propynylbenzene molecular units on highly oriented pyrolytic graphite. The reaction occurs within the self-assembled monolayer and leads to the generation of covalently coupled 1,5-hexadiyne and para-terphenyl derivatives under topological control. Such photochemical uncatalysed pathway represents an original approach in the field of topological C-C coupling at the solid/liquid interface and provides new insight into the low temperature formation of aromatic compounds at the surface of carbonaceous supports.
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Affiliation(s)
- Luciano Colazzo
- Center for Quantum Nanoscience, Institute for Basic Science (IBS), Seoul, 03760, Republic of Korea.,Department of Physics, Ewha Womans University, Seoul, 03760, Republic of Korea
| | - Maurizio Casarin
- Dipartimento di Scienze Chimiche, Università di Padova, Via Marzolo 1, 35131, Padova, Italy.,CNR-ICMATE, Via Marzolo 1, 35131, Padova, Italy
| | - Mauro Sambi
- Dipartimento di Scienze Chimiche, Università di Padova, Via Marzolo 1, 35131, Padova, Italy.,Consorzio INSTM, Unità di Ricerca di Padova, Via Marzolo 1, 35131, Padova, Italy
| | - Francesco Sedona
- Dipartimento di Scienze Chimiche, Università di Padova, Via Marzolo 1, 35131, Padova, Italy
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6
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Sztáray B, Voronova K, Torma KG, Covert KJ, Bodi A, Hemberger P, Gerber T, Osborn DL. CRF-PEPICO: Double velocity map imaging photoelectron photoion coincidence spectroscopy for reaction kinetics studies. J Chem Phys 2017; 147:013944. [DOI: 10.1063/1.4984304] [Citation(s) in RCA: 89] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Bálint Sztáray
- Department of Chemistry, University of the Pacific, Stockton, California 95211, USA
| | - Krisztina Voronova
- Department of Chemistry, University of the Pacific, Stockton, California 95211, USA
| | - Krisztián G. Torma
- Department of Chemistry, University of the Pacific, Stockton, California 95211, USA
| | - Kyle J. Covert
- Department of Chemistry, University of the Pacific, Stockton, California 95211, USA
| | - Andras Bodi
- Laboratory for Femtochemistry and Synchrotron Radiation, Paul Scherrer Institute (PSI), CH-5232 Villigen, Switzerland
| | - Patrick Hemberger
- Laboratory for Femtochemistry and Synchrotron Radiation, Paul Scherrer Institute (PSI), CH-5232 Villigen, Switzerland
| | - Thomas Gerber
- Laboratory for Femtochemistry and Synchrotron Radiation, Paul Scherrer Institute (PSI), CH-5232 Villigen, Switzerland
| | - David L. Osborn
- Combustion Research Facility, Sandia National Laboratories, Livermore, California 94551, USA
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7
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Chang CH, Nesbitt DJ. High resolution spectroscopy of jet cooled phenyl radical: The ν1 and ν2 a1 symmetry C–H stretching modes. J Chem Phys 2016; 145:044304. [DOI: 10.1063/1.4955295] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Chih-Hsuan Chang
- JILA, National Institute of Standards and Technology, University of Colorado, Boulder, Colorado 80309, USA and Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309, USA
| | - David J. Nesbitt
- JILA, National Institute of Standards and Technology, University of Colorado, Boulder, Colorado 80309, USA and Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309, USA
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8
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Kerisit N, Rouxel C, Colombel-Rouen S, Toupet L, Guillemin JC, Trolez Y. Synthesis, Chemistry, and Photochemistry of Methylcyanobutadiyne in the Context of Space Science. J Org Chem 2016; 81:3560-7. [DOI: 10.1021/acs.joc.6b00205] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Nicolas Kerisit
- Ecole Nationale
Supérieure de Chimie de Rennes, UMR 6226, CNRS, 11 allée de Beaulieu, CS
50837, 35708 Rennes cedex
7, France
| | - Cédric Rouxel
- Ecole Nationale
Supérieure de Chimie de Rennes, UMR 6226, CNRS, 11 allée de Beaulieu, CS
50837, 35708 Rennes cedex
7, France
| | - Sophie Colombel-Rouen
- Ecole Nationale
Supérieure de Chimie de Rennes, UMR 6226, CNRS, 11 allée de Beaulieu, CS
50837, 35708 Rennes cedex
7, France
| | - Loïc Toupet
- Institut de Physique
de Rennes, UMR 6251, CNRS, Université de Rennes 1, 263 avenue du Général
Leclerc, 35042 Rennes cedex, France
| | - Jean-Claude Guillemin
- Ecole Nationale
Supérieure de Chimie de Rennes, UMR 6226, CNRS, 11 allée de Beaulieu, CS
50837, 35708 Rennes cedex
7, France
| | - Yann Trolez
- Ecole Nationale
Supérieure de Chimie de Rennes, UMR 6226, CNRS, 11 allée de Beaulieu, CS
50837, 35708 Rennes cedex
7, France
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9
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Chang CH, Nesbitt DJ. Sub-Doppler infrared spectroscopy of propargyl radical (H2CCCH) in a slit supersonic expansion. J Chem Phys 2015; 142:244313. [DOI: 10.1063/1.4922931] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Affiliation(s)
- Chih-Hsuan Chang
- JILA, National Institute of Standards and Technology, University of Colorado, Boulder, Colorado 80309, USA and Department of Chemistry and Biochemistry, University of Colorado at Boulder, Boulder, Colorado 80309, USA
| | - David J. Nesbitt
- JILA, National Institute of Standards and Technology, University of Colorado, Boulder, Colorado 80309, USA and Department of Chemistry and Biochemistry, University of Colorado at Boulder, Boulder, Colorado 80309, USA
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10
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Knyazev VD, Popov KV. Kinetics of the Self Reaction of Cyclopentadienyl Radicals. J Phys Chem A 2015; 119:7418-29. [DOI: 10.1021/acs.jpca.5b00644] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Vadim D. Knyazev
- Research Center for Chemical
Kinetics, Department of Chemistry, The Catholic University of America, Washington, District of Columbia 20064, United States
| | - Konstantin V. Popov
- Research Center for Chemical
Kinetics, Department of Chemistry, The Catholic University of America, Washington, District of Columbia 20064, United States
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11
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Sharath N, Reddy KPJ, Arunan E. Thermal Decomposition of Propargyl Alcohol: Single Pulse Shock Tube Experimental and ab Initio Theoretical Study. J Phys Chem A 2014; 118:5927-38. [DOI: 10.1021/jp505145j] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- N. Sharath
- Department of Aerospace Engineering and ‡Department of Inorganic and Physical
Chemistry, Indian Institute of Science, 560 012 Bangalore, India
| | - K. P. J. Reddy
- Department of Aerospace Engineering and ‡Department of Inorganic and Physical
Chemistry, Indian Institute of Science, 560 012 Bangalore, India
| | - E. Arunan
- Department of Aerospace Engineering and ‡Department of Inorganic and Physical
Chemistry, Indian Institute of Science, 560 012 Bangalore, India
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12
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Kerisit N, Toupet L, Trolez Y, Guillemin JC. Methylcyanobutadiyne: Synthesis, X-ray Structure and Photochemistry; Towards an Explanation of Its Formation in the Interstellar Medium. Chemistry 2013; 19:17683-6. [DOI: 10.1002/chem.201303377] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2013] [Indexed: 11/07/2022]
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13
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Moradi CP, Morrison AM, Klippenstein SJ, Goldsmith CF, Douberly GE. Propargyl + O2 Reaction in Helium Droplets: Entrance Channel Barrier or Not? J Phys Chem A 2013; 117:13626-35. [DOI: 10.1021/jp407652f] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Christopher P. Moradi
- Department
of Chemistry, University of Georgia, Athens, Georgia 30602, United States
| | - Alexander M. Morrison
- Department
of Chemistry, University of Georgia, Athens, Georgia 30602, United States
| | - Stephen J. Klippenstein
- Chemical
Sciences and Engineering Division, Argonne National Laboratory, Argonne, Illinois 60439, United States
| | - C. Franklin Goldsmith
- Chemical
Sciences and Engineering Division, Argonne National Laboratory, Argonne, Illinois 60439, United States
| | - Gary E. Douberly
- Department
of Chemistry, University of Georgia, Athens, Georgia 30602, United States
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14
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Matsugi A, Suma K, Miyoshi A. Kinetics and Mechanisms of the Allyl + Allyl and Allyl + Propargyl Recombination Reactions. J Phys Chem A 2011; 115:7610-24. [DOI: 10.1021/jp203520j] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Akira Matsugi
- Department of Chemical System Engineering, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
| | - Kohsuke Suma
- Department of Chemical System Engineering, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
| | - Akira Miyoshi
- Department of Chemical System Engineering, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
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15
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Castiglioni L, Vukovic S, Crider PE, Lester WA, Neumark DM. Intramolecular competition in the photodissociation of C3D3 radicals at 248 and 193 nm. Phys Chem Chem Phys 2010; 12:10714-22. [DOI: 10.1039/c0cp00380h] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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16
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Jochnowitz EB, Zhang X, Nimlos MR, Flowers BA, Stanton JF, Ellison GB. Infrared Spectrum of the Propargyl Peroxyl Radical, HC≡C—CH2OO X̃ 2A′′. J Phys Chem A 2009; 114:1498-507. [DOI: 10.1021/jp907806g] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Evan B. Jochnowitz
- Department of Chemistry & Biochemistry, University of Colorado, Boulder, Colorado 80309-0215, Institute for Physical Chemistry, University of Basel, Klingelbergstrasse 80, CH-4056 Basel, Switzerland, Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, California 91109-8099, National Renewable Energy Laboratory, 1617 Cole Boulevard, Golden, Colorado 80401, Earth and Environmental Sciences Division, Los Alamos National Laboratory, Mail Stop D462, Los Alamos, New
| | - Xu Zhang
- Department of Chemistry & Biochemistry, University of Colorado, Boulder, Colorado 80309-0215, Institute for Physical Chemistry, University of Basel, Klingelbergstrasse 80, CH-4056 Basel, Switzerland, Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, California 91109-8099, National Renewable Energy Laboratory, 1617 Cole Boulevard, Golden, Colorado 80401, Earth and Environmental Sciences Division, Los Alamos National Laboratory, Mail Stop D462, Los Alamos, New
| | - Mark R. Nimlos
- Department of Chemistry & Biochemistry, University of Colorado, Boulder, Colorado 80309-0215, Institute for Physical Chemistry, University of Basel, Klingelbergstrasse 80, CH-4056 Basel, Switzerland, Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, California 91109-8099, National Renewable Energy Laboratory, 1617 Cole Boulevard, Golden, Colorado 80401, Earth and Environmental Sciences Division, Los Alamos National Laboratory, Mail Stop D462, Los Alamos, New
| | - Bradley A. Flowers
- Department of Chemistry & Biochemistry, University of Colorado, Boulder, Colorado 80309-0215, Institute for Physical Chemistry, University of Basel, Klingelbergstrasse 80, CH-4056 Basel, Switzerland, Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, California 91109-8099, National Renewable Energy Laboratory, 1617 Cole Boulevard, Golden, Colorado 80401, Earth and Environmental Sciences Division, Los Alamos National Laboratory, Mail Stop D462, Los Alamos, New
| | - John F. Stanton
- Department of Chemistry & Biochemistry, University of Colorado, Boulder, Colorado 80309-0215, Institute for Physical Chemistry, University of Basel, Klingelbergstrasse 80, CH-4056 Basel, Switzerland, Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, California 91109-8099, National Renewable Energy Laboratory, 1617 Cole Boulevard, Golden, Colorado 80401, Earth and Environmental Sciences Division, Los Alamos National Laboratory, Mail Stop D462, Los Alamos, New
| | - G. Barney Ellison
- Department of Chemistry & Biochemistry, University of Colorado, Boulder, Colorado 80309-0215, Institute for Physical Chemistry, University of Basel, Klingelbergstrasse 80, CH-4056 Basel, Switzerland, Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, California 91109-8099, National Renewable Energy Laboratory, 1617 Cole Boulevard, Golden, Colorado 80401, Earth and Environmental Sciences Division, Los Alamos National Laboratory, Mail Stop D462, Los Alamos, New
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17
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Vasiliou A, Nimlos MR, Daily JW, Ellison GB. Thermal Decomposition of Furan Generates Propargyl Radicals. J Phys Chem A 2009; 113:8540-7. [DOI: 10.1021/jp903401h] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- AnGayle Vasiliou
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309-0215, National Renewable Energy Laboratory, 1617 Cole Boulevard, Golden, Colorado 80401, and Center for Combustion and Environmental Research, Department of Mechanical Engineering, University of Colorado at Boulder, Boulder, Colorado 80309-0427
| | - Mark R. Nimlos
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309-0215, National Renewable Energy Laboratory, 1617 Cole Boulevard, Golden, Colorado 80401, and Center for Combustion and Environmental Research, Department of Mechanical Engineering, University of Colorado at Boulder, Boulder, Colorado 80309-0427
| | - John W. Daily
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309-0215, National Renewable Energy Laboratory, 1617 Cole Boulevard, Golden, Colorado 80401, and Center for Combustion and Environmental Research, Department of Mechanical Engineering, University of Colorado at Boulder, Boulder, Colorado 80309-0427
| | - G. Barney Ellison
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309-0215, National Renewable Energy Laboratory, 1617 Cole Boulevard, Golden, Colorado 80401, and Center for Combustion and Environmental Research, Department of Mechanical Engineering, University of Colorado at Boulder, Boulder, Colorado 80309-0427
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18
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Crider PE, Castiglioni L, Kautzman KE, Neumark DM. Photodissociation of the propargyl and propynyl (C3D3) radicals at 248 and 193 nm. J Chem Phys 2009; 130:044310. [DOI: 10.1063/1.3067705] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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19
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Ismail H, Abel PR, Green WH, Fahr A, Jusinski LE, Knepp AM, Zádor J, Meloni G, Selby TM, Osborn DL, Taatjes CA. Temperature-Dependent Kinetics of the Vinyl Radical (C2H3) Self-Reaction. J Phys Chem A 2009; 113:1278-86. [DOI: 10.1021/jp8096132] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Huzeifa Ismail
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
| | | | | | - Askar Fahr
- Department of Chemistry, Howard University, Washington, D.C. 20059
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Selby TM, Meloni G, Goulay F, Leone SR, Fahr A, Taatjes CA, Osborn DL. Synchrotron Photoionization Mass Spectrometry Measurements of Kinetics and Product Formation in the Allyl Radical (H2CCHCH2) Self-Reaction. J Phys Chem A 2008; 112:9366-73. [DOI: 10.1021/jp802330k] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Talitha M. Selby
- Sandia National Laboratories, Combustion Research Facility, MS 9055, Livermore, California 94551-0969, Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, and Department of Chemistry, Howard University, Washington, D.C. 20059
| | - Giovanni Meloni
- Sandia National Laboratories, Combustion Research Facility, MS 9055, Livermore, California 94551-0969, Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, and Department of Chemistry, Howard University, Washington, D.C. 20059
| | - Fabien Goulay
- Sandia National Laboratories, Combustion Research Facility, MS 9055, Livermore, California 94551-0969, Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, and Department of Chemistry, Howard University, Washington, D.C. 20059
| | - Stephen R. Leone
- Sandia National Laboratories, Combustion Research Facility, MS 9055, Livermore, California 94551-0969, Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, and Department of Chemistry, Howard University, Washington, D.C. 20059
| | - Askar Fahr
- Sandia National Laboratories, Combustion Research Facility, MS 9055, Livermore, California 94551-0969, Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, and Department of Chemistry, Howard University, Washington, D.C. 20059
| | - Craig A. Taatjes
- Sandia National Laboratories, Combustion Research Facility, MS 9055, Livermore, California 94551-0969, Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, and Department of Chemistry, Howard University, Washington, D.C. 20059
| | - David L. Osborn
- Sandia National Laboratories, Combustion Research Facility, MS 9055, Livermore, California 94551-0969, Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, and Department of Chemistry, Howard University, Washington, D.C. 20059
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22
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Gu X, Kaiser RI, Mebel AM. Chemistry of energetically activated cumulenes - from allene (H2CCCH2) to hexapentaene (H2CCCCCCH2). Chemphyschem 2008; 9:350-69. [PMID: 18275046 DOI: 10.1002/cphc.200700609] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
During the last decade, experimental and theoretical studies on the unimolecular decomposition of cumulenes (H(2)C(n)H(2)) from propadiene (H(2)CCCH(2)) to hexapentaene (H(2)CCCCCCH(2)) have received considerable attention due to the importance of these carbon-bearing molecules in combustion flames, chemical vapor deposition processes, atmospheric chemistry, and the chemistry of the interstellar medium. Cumulenes and their substituted counterparts also have significant technical potential as elements for molecular machines (nanomechanics), molecular wires (nano-electronics), nonlinear optics, and molecular sensors. In this review, we present a systematic overview of the stability, formation, and unimolecular decomposition of chemically, photo-chemically, and thermally activated small to medium-sized cumulenes in extreme environments. By concentrating on reactions under gas phase thermal conditions (pyrolysis) and on molecular beam experiments conducted under single-collision conditions (crossed beam and photodissociation studies), a comprehensive picture on the unimolecular decomposition dynamics of cumulenes transpires.
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Affiliation(s)
- Xibin Gu
- Department of Chemistry, University of Hawai'i at Manoa, Honolulu, HI 96822, USA
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23
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Georgievskii Y, Miller JA, Klippenstein SJ. Association rate constants for reactions between resonance-stabilized radicals: C3H3 + C3H3, C3H3 + C3H5, and C3H5 + C3H5. Phys Chem Chem Phys 2007; 9:4259-68. [PMID: 17687474 DOI: 10.1039/b703261g] [Citation(s) in RCA: 124] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Reactions between resonance-stabilized radicals play an important role in combustion chemistry. The theoretical prediction of rate coefficients and product distributions for such reactions is complicated by the fact that the initial complex-formation steps and some dissociation steps are barrierless. In this paper direct variable reaction coordinate transition state theory (VRC-TST) is used to predict accurately the association rate constants for the self and cross reactions of propargyl and allyl radicals. For each reaction, a set of multifaceted dividing surfaces is used to account for the multiple possible addition channels. Because of their resonant nature the geometric relaxation of the radicals is important. Here, the effect of this relaxation is explicitly calculated with the UB3LYP/cc-pvdz method for each mutual orientation encountered in the configurational integrals over the transition state dividing surfaces. The final energies are obtained from CASPT2/cc-pvdz calculations with all pi-orbitals in the active space. Evaluations along the minimum energy path suggest that basis set corrections are negligible. The VRC-TST approach was also used to calculate the association rate constant and the corresponding number of states for the C(6)H(5) + H --> C(6)H(6) exit channel of the C(3)H(3) + C(3)H(3) reaction, which is also barrierless. For this reaction, the interaction energies were evaluated with the CASPT2(2e,2o)/cc-pvdz method and a 1-D correction is included on the basis of CAS+1+2+QC/aug-cc-pvtz calculations for the CH(3) + H reference system. For the C(3)H(3) + C(3)H(3) reaction, the VRC-TST results for the energy and angular momentum resolved numbers of states in the entrance channels and in the C(6)H(5) + H exit channel are incorporated in a master equation simulation to determine the temperature and pressure dependence of the phenomenological rate coefficients. The rate constants for the C(3)H(3) + C(3)H(3) and C(3)H(5) + C(3)H(5) self-reactions compare favorably with the available experimental data. To our knowledge there are no experimental rate data for the C(3)H(3) + C(3)H(5) reaction.
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Affiliation(s)
- Yuri Georgievskii
- Combustion Research Facility, Sandia National Laboratories, Livermore, CA 94551-0969, USA
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24
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Goulay F, Osborn DL, Taatjes CA, Zou P, Meloni G, Leone SR. Direct detection of polyynes formation from the reaction of ethynyl radical (C2H) with propyne (CH3–CCH) and allene (CH2CCH2). Phys Chem Chem Phys 2007; 9:4291-300. [PMID: 17687477 DOI: 10.1039/b614502g] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The reactions of the ethynyl radical (C(2)H) with propyne and allene are studied at room temperature using an apparatus that combines the tunability of the vacuum ultraviolet radiation of the Advanced Light Source at Lawrence Berkeley National Laboratory with time-resolved mass spectrometry. The C(2)H radical is prepared by 193-nm photolysis of CF(3)CCH and the mass spectrum of the reacting mixture is monitored in time using synchrotron-photoionization with a dual-sector mass spectrometer. Analysis using photoionization efficiency curves allows the isomer-specific detection of individual polyynes of chemical formula C(5)H(4) produced by both reactions. The product branching ratios are estimated for each isomer. The reaction of propyne with ethynyl gives 50-70% diacetylene (H-C[triple bond]C-C[triple bond]C-H) and 50-30% C(5)H(4), with a C(5)H(4)-isomer distribution of 15-20% ethynylallene (CH(2)=C=CH-C[triple bond]CH) and 85-80% methyldiacetylene (CH(3)-C[triple bond]C-C[triple bond]CH). The reaction of allene with ethynyl gives 35-45% ethynylallene, 20-25% methyldiacetylene and 45-30% 1,4-pentadiyne (HC[triple bond]C-CH(2)-C[triple bond]CH). Diacetylene is most likely not produced by this reaction; an upper limit of 30% on the branching fraction to diacetylene can be derived from the present experiment. The mechanisms of polyynes formation by these reactions as well as the implications for Titan's atmospheric chemistry are discussed.
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Affiliation(s)
- Fabien Goulay
- Departments of Chemistry and Physics, and Lawrence Berkeley National Laboratory, University of California, Berkeley, CA 94720, USA
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25
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Miller CH, Tang W, Tranter RS, Brezinsky K. Shock tube pyrolysis of 1,2,4,5-hexatetraene. J Phys Chem A 2006; 110:3605-13. [PMID: 16526641 DOI: 10.1021/jp055990v] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
1,2,4,5-Hexatetraene (1245HT) is, according to theory, a key intermediate to benzene from propargyl radicals in a variety of flames; however, it has only been experimentally observed once in previous studies of the C3H3 + C3H3 reaction. To determine if it is indeed an intermediate to benzene formation, 1245HT was synthesized, via a Grignard reaction, and pyrolysized in a single-pulse shock tube at two nominal pressures of 22 and 40 bar over a temperature range from 540 to 1180 K. At temperatures T < 700 K, 1245HT converts efficiently to 3,4-dimethylenecyclobutene (34DMCB) with a rate constant of k = 10(10.16) x exp(-23.4 kcal/RT), which is in good agreement with the one calculated by Miller and Klippenstein. At higher temperatures, various C6H6 isomers were generated, which is consistent with theory and earlier experimental studies. Thus, the current work strongly supports the theory that 1245HT plays a bridging role in forming benzene from propargyl radicals. RRKM modeling of the current data set has also been carried out with the Miller-Klippenstein potential. It was found that the theory gives reasonably good predictions of the experimental observations of 1245HT, 1,5-hexadiyne (15HD), and 34DMCB in the current study and in our earlier studies of 15HD pyrolysis and propargyl recombination; however, there is considerable discrepancy between experiment and theory for the isomerization route of 1,2-hexadien-5-yne (12HD5Y) --> 2-ethynyl-1,3-butadiene (2E13BD) --> fulvene.
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Affiliation(s)
- Cheryl H Miller
- Department of Mechanical Engineering, University of Illinois at Chicago, 842 West Taylor Street, M/C 251, Chicago, IL 60607, USA
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26
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DeSain JD, Jusinski LE, Taatjes CA. Ultraviolet photochemistry of trichlorovinylsilane and allyltrichlorosilane: vinyl radical (HCCH2) and allyl radical (H2CCHCH2) production in 193 nm photolysis. Phys Chem Chem Phys 2006; 8:2240-8. [PMID: 16688306 DOI: 10.1039/b600755d] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The absolute gas phase ultraviolet absorption spectra of trichlorovinylsilane and allyltrichlorosilane have been measured from 191 to 220 nm. Over this region the absorption spectra of both species are broad and relatively featureless, and their cross sections increase with decreasing wavelength. The electronic transitions of trichlorovinylsilane were calculated by ab initio quantum chemical methods and the observed absorption bands assigned to the A(1)A''<-- X[combining tilde](1)A'' transition. The maximum absorption cross section in the region, at 191 nm, is sigma = (8.50 +/- 0.06) x 10(-18) cm(2) for trichlorovinylsilane and sigma = (2.10 +/- 0.02) x 10(-17) cm(2) for allyltrichlorosilane. The vinyl radical and the allyl radical are formed promptly from the 193 nm photolysis of their respective trichlorosilane precursors. By comparison of the transient visible absorption and the 1315 nm I atom absorption from 266 nm photolysis of vinyl iodide and allyl iodide, the absorption cross sections at 404 nm of vinyl radical ((2.9 +/- 0.4) x 10(-19) cm(2)) and allyl radical ((3.6 +/- 0.8) x 10(-19) cm(2)) were derived. These cross sections are in significant disagreement with literature values derived from kinetic modeling of allyl or vinyl radical self-reactions. Using these cross sections, the vinyl radical yield from trichlorovinylsilane was determined to be phi = (0.9 +/- 0.2) per 193 nm photon absorbed, and the allyl radical yield from allyltrichlorosilane phi = (0.7 +/- 0.2) per 193 nm photon absorbed.
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Affiliation(s)
- John D DeSain
- The Aerospace Corporation, El Segundo, CA 90245-4691, USA.
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27
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Tang W, Tranter RS, Brezinsky K. Isomeric Product Distributions from the Self-Reaction of Propargyl Radicals. J Phys Chem A 2005; 109:6056-65. [PMID: 16833941 DOI: 10.1021/jp050640u] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We have investigated the isomeric C6H6 product distributions of the self-reaction of propargyl (C3H3) radicals at two nominal pressures of 25 and 50 bar over the temperature range 720-1350 K. Experiments were performed using propargyl iodide as the radical precursor in a high-pressure single-pulse shock tube with a residence time of 1.6-2.0 ms. The relative yields of the C6H6 products are strongly temperature dependent, and the main products are 1,5-hexadiyne (15HD), 1,2-hexadiene-5-yne (12HD5Y), 3,4-dimethylenecyclobutene (34DMCB), 2-ethynyl-1,3-butadiene (2E13BD), fulvene, and benzene, with the minor products being cis- and trans-1,3-hexadiene-5-yne (13HD5Y). 1,2,4,5-Hexatetraene (1245HT) was observed below 750 K but the concentrations were too low to be quantified. The experimentally determined entry branching ratios are: 44% 15HD, 38% 12HD5Y, and 18% 1245HT, which is efficiently converted to 34DMCB. Following the initial recombination step, various C6H6 isomers are formed by thermal rearrangement. The experimentally observed concentrations for the C6H6 species are in good agreement with earlier experiments on 15HD thermal rearrangement.
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Affiliation(s)
- Weiyong Tang
- Department of Mechanical Engineering, University of Illinois at Chicago, 842 West Taylor Street, M/C 251, Chicago, Illinois, 60607, USA
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28
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Portnov A, Bespechansky E, Ganot Y, Rosenwaks S, Bar I. Determining the vibrational pattern via overtone cold spectra: C-H methyl stretches of propyne. J Chem Phys 2005; 122:224316. [PMID: 15974677 DOI: 10.1063/1.1930832] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Vibrationally mediated photodissociation and photoacoustic (PA) spectroscopy were employed for studying the intramolecular dynamics of propyne initially excited to the first through fourth overtone of methyl C-H stretching modes. Room-temperature PA and jet-cooled action spectra, monitoring the absorption of the parent and the yield of the ensuing H photofragments, respectively, were obtained. The PA spectra exhibit mainly broad features, while the action spectra, due to inhomogeneous structure reduction, expose multiple peaks of recognizable shapes in the differing overtone manifolds. Symmetric rotor simulations of the band contours of the action spectra allowed retrieving of band origins and linewidths. The linewidths of the bands in each manifold enabled estimates for energy redistribution times out of the corresponding states to the bath states, the times ranging from 18+/-6 ps for two quanta of C-H excitation to subpicosecond for five quanta. The data were also analyzed in terms of a normal-mode model and a joint local-/normal-mode model. These models enabled determination of harmonic frequencies, anharmonicities, and interaction parameters reproducing the observed data in all monitored regions and provided spectral assignments. The measured Doppler profiles were well fitted by Gaussians with widths suggesting low average translational energies for the released H photofragments. These low energies and their similarities to those for dissociation of propyne isotopomers preexcited to acetylenic C-H stretches were ascribed to an indirect dissociation process occurring after internal conversion to the ground electronic state and isomerization to allene.
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Affiliation(s)
- Alex Portnov
- Department of Physics, Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel
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Fahr A, Laufer AH. UV-Absorption Spectra of the Radical Transients Generated from the 193-nm Photolysis of Allene, Propyne, and 2-Butyne. J Phys Chem A 2005; 109:2534-9. [PMID: 16833555 DOI: 10.1021/jp0406058] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The 193-nm photochemistry of allene (H2C=C=CH2), propyne (H3C-C[triple bond]CH), and 2-butyne (H3C-C[triple bond]C-CH3) has been examined, and the UV spectral region between 220 and 350 nm has been surveyed for UV-absorption detection of transient species generated from the photolysis of these molecules. Time-resolved UV-absorption spectroscopy was used for detection of transient absorption. Gas chromatographic/mass spectroscopic (GC/MS) analysis of the photolyzed samples were employed for identification of the final photodissociation products. An emphasis of the study has been on the examination of possibilities of formation of different C3H3 isomeric radicals, that is, propargyl (H2CCCH) or propynyl (H3CCC), from the 193-nm photolysis of these molecules. Survey of the UV spectral region, following the 193-nm photolysis of dilute mixtures of allene/He resulted in detection of a strong absorption band around 230 nm and a weaker band in the 320-nm region with a relative intensity of about 8:1. The time-resolved absorption traces after the photolysis event show an instantaneous rise, followed by a simple decay. The spectral features, observed in this work, following 193-nm photolysis of allene are in good agreement with the previously reported spectrum of H2CCCH radical in the 240- and 320-nm regions and are believed to originate primarily from propargyl radicals. In comparison, the spectra obtained from the 193-nm photolysis of dilute mixtures of HCCCH3/He and CH3CCCH3/He were nearly identical, consisting of two relatively broad bands centered at about 240- and 320-nm regions with a relative intensity of about 2:1, respectively. In addition, the time-resolved absorption traces after photolysis of propyne and 2-butyne samples, both in the 240 and 320 nm regions, indicated an instant rise followed by an additional slower absorption rise. The distinct differences between the results of allene with those of propyne and 2-butyne suggest the observed absorption features following 193-nm photolysis of these molecules are likely to be composite with contributions from a number of transient species other than propargyl radicals. Propyne and 2-butyne are structurally similar. The methyl (CH3) and propynyl (CH3C[triple bond]C) radicals are likely to be among the photodissociation products of 2-butyne, and similarly, propynyl is likely to be a photodissociation product of propyne. GC/MS product analysis of photolyzed 2-butyne/He mixtures indicates the formation of C2H6 (formed from the combination of CH3 radicals), and a number of C6H6 and C4H6 isomers formed from self- and cross reactions of C3H3 and CH3 radicals, including 1,5-hexadiyne and 2,4-hexadyine, that are potential products of combination reactions of propargyl as well as propynyl radicals.
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Affiliation(s)
- Askar Fahr
- Department of Chemistry, American University, Washington DC 20016-8014, USA.
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30
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Yu HG, Muckerman JT. Ab Initio and Direct Dynamics Studies of the Reaction of Singlet Methylene with Acetylene and the Lifetime of the Cyclopropene Complex. J Phys Chem A 2005; 109:1890-6. [PMID: 16833521 DOI: 10.1021/jp045049w] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The energetics of the (1)CH(2) + C(2)H(2) --> H + C(3)H(3) reaction are accurately calculated using an extrapolated coupled-cluster/complete basis set (CBS) method based on the cc-pVDZ, cc-pVTZ, and cc-pVQZ basis sets. The reaction enthalpy (0 K) is predicted to be -20.33 kcal/mol. This reaction has no classical barrier in either the entrance or exit channel. However, there are several stable intermediates-cyclopropene (c-C(3)H(4)), allene (CH(2)CCH(2)), and propyne (CH(3)CCH)-along the minimum energy path. These intermediates with zero-point energy corrections lie below the reactants by 87.11 (c-C(3)H(4)), 109.69 (CH(2)CCH(2)), and 110.78 kcal/mol (CH(3)CCH). The vibrationally adiabatic ground-state (VAG) barrier height for c-C(3)H(4) isomerization to allene is obtained as 45.2 kcal/mol, and to propyne as 37.2 kcal/mol. In addition, the (1)CH(2) + C(2)H(2) reaction is investigated utilizing the dual-level "scaling all correlation" (SAC) ab initio method of Truhlar et al., i.e., the UCCSD(SAC)/cc-pVDZ theory. Results show that the reaction occurs via long-lived complexes. The lifetime of the cyclopropene intermediate is obtained as 3.2 +/- 0.4 ps. It is found that the intermediate propyne can be formed directly from reactants through the insertion of (1)CH(2) into a C-H bond of C(2)H(2). However, compared to the major mechanism in which the propyne is produced through a ring-opening of the cyclopropene complex, this reaction pathway is much less favorable. Finally, the theoretical thermal rate constant exhibits a negative temperature dependence, which is in excellent agreement with the previous results. The temperature dependence is consistent with the earlier RRKM results but weaker than the experimental observations at high temperatures.
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Affiliation(s)
- Hua-Gen Yu
- Department of Chemistry, Brookhaven National Laboratory, Upton, New York 11973-5000, USA
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31
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Davis HF, Shu J, Peterka DS, Ahmed M. Crossed beams study of the reaction 1CH2+C2H2→C3H3+H. J Chem Phys 2004; 121:6254-7. [PMID: 15446918 DOI: 10.1063/1.1785152] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The reaction of electronically excited singlet methylene (1CH2) with acetylene (C2H2) was studied using the method of crossed molecular beams at a mean collision energy of 3.0 kcal/mol. The angular and velocity distributions of the propargyl radical (C3H3) products were measured using single photon ionization (9.6 eV) at the advanced light source. The measured distributions indicate that the mechanism involves formation of a long-lived C3H4 complex followed by simple C-H bond fission producing C3H3+H. This work, which is the first crossed beams study of a reaction involving an electronically excited polyatomic molecule, demonstrates the feasibility of crossed molecular beam studies of reactions involving 1CH2.
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Affiliation(s)
- H Floyd Davis
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853-1301, USA
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Tranter RS, Tang W, Anderson KB, Brezinsky K. Shock Tube Study of Thermal Rearrangement of 1,5-Hexadiyne over Wide Temperature and Pressure Regime. J Phys Chem A 2004. [DOI: 10.1021/jp037310z] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Robert S. Tranter
- Departments of Mechanical Engineering and Chemical Engineering, University of Illinois at Chicago, 842 West Taylor Street, M/C 251, Chicago, Illinois 60607, and Chemistry Division, Argonne National Laboratory, Argonne, Illinois 60439
| | - Weiyong Tang
- Departments of Mechanical Engineering and Chemical Engineering, University of Illinois at Chicago, 842 West Taylor Street, M/C 251, Chicago, Illinois 60607, and Chemistry Division, Argonne National Laboratory, Argonne, Illinois 60439
| | - Ken B. Anderson
- Departments of Mechanical Engineering and Chemical Engineering, University of Illinois at Chicago, 842 West Taylor Street, M/C 251, Chicago, Illinois 60607, and Chemistry Division, Argonne National Laboratory, Argonne, Illinois 60439
| | - Kenneth Brezinsky
- Departments of Mechanical Engineering and Chemical Engineering, University of Illinois at Chicago, 842 West Taylor Street, M/C 251, Chicago, Illinois 60607, and Chemistry Division, Argonne National Laboratory, Argonne, Illinois 60439
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33
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Qadiri RH, Feltham EJ, Hendrik Nahler N, Pérez Garcı́a R, Ashfold MNR. Propyne and allene photolysis at 193.3 nm and at 121.6 nm. J Chem Phys 2003. [DOI: 10.1063/1.1627761] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
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34
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Howe PT, Fahr A. Pressure and Temperature Effects on Product Channels of the Propargyl (HC⋮CCH2) Combination Reaction and the Formation of the “First Ring”. J Phys Chem A 2003. [DOI: 10.1021/jp0307497] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Affiliation(s)
- Pui-Teng Howe
- Department of Chemistry, American University, Washington, D.C., 20016-8014
| | - Askar Fahr
- Physical and Chemical Properties Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899
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35
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Shafir EV, Slagle IR, Knyazev VD. Kinetics and Products of the Self-Reaction of Propargyl Radicals. J Phys Chem A 2003. [DOI: 10.1021/jp035648n] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Eugene V. Shafir
- Research Center for Chemical Kinetics, Department of Chemistry, The Catholic University of America, Washington, DC 20064
| | - Irene R. Slagle
- Research Center for Chemical Kinetics, Department of Chemistry, The Catholic University of America, Washington, DC 20064
| | - Vadim D. Knyazev
- Research Center for Chemical Kinetics, Department of Chemistry, The Catholic University of America, Washington, DC 20064
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36
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Giri BR, Hippler H, Olzmann M, Unterreiner AN. The rate coefficient of the C3H3 + C3H3reaction from UV absorption measurements after photolysis of dipropargyl oxalate. Phys Chem Chem Phys 2003. [DOI: 10.1039/b308518j] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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