1
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Morgan KM, Baraban JH. Thermochemical Studies of Small Carbohydrates. J Org Chem 2024; 89:1769-1776. [PMID: 38227766 PMCID: PMC10845155 DOI: 10.1021/acs.joc.3c02465] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2023] [Revised: 12/14/2023] [Accepted: 12/28/2023] [Indexed: 01/18/2024]
Abstract
Despite their prevalence in biomass and importance in biochemistry, there is still much to be learned about simple carbohydrates. Gas-phase calculations are reported here on two trioses and three tetroses. For aldotetroses, both the open-chain and furanose forms are considered. Enthalpies of reduction to polyols are calculated at the CBS-APNO level of theory, and comparisons to simple aldehydes and ketones are made. Heats of formation are calculated in two ways with overall good agreement. The heat of formation of glyceraldehyde obtained from modified HEAT calculations is also reported. Finally, calculated bond energies are presented, and the influence of the structure on the bond energies is discussed.
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Affiliation(s)
- Kathleen M. Morgan
- Department
of Chemistry, Xavier University of Louisiana, 1 Drexel Drive, New Orleans, Louisiana 70125, United States
| | - Joshua H. Baraban
- Department
of Chemistry, Ben-Gurion University of the
Negev, Beer Sheva 841051, Israel
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2
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Legg HN, Narkin KM, McCunn LR, Parish CA, Song X. Experimental and Theoretical Study of Oxolan-3-one Thermal Decomposition. J Phys Chem A 2022; 126:7084-7093. [PMID: 36194512 DOI: 10.1021/acs.jpca.2c03254] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The thermal decomposition of oxolan-3-one, a common component of the bio-oil formed during biomass pyrolysis, has been studied using ab initio calculations and experiments employing pulsed gas-phase pyrolysis with matrix-isolation FTIR product detection. Four pathways for unimolecular decomposition were predicted using computational methods. The dominant reaction channel led to carbon monoxide, formaldehyde, and ethylene, all of which were observed experimentally. The other channels led to an assortment of products including ketene, water, propyne, and acetylene, which were all confirmed in the matrix-isolation FTIR spectra. There is also evidence for the production of substituted ketenes in pyrolysis, most likely hydroxyketene and methylketene.
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Affiliation(s)
- Heather N Legg
- Department of Chemistry, Marshall University, 1 John Marshall Drive, Huntington, West Virginia25755, United States
| | - Kathryn M Narkin
- Department of Chemistry, Marshall University, 1 John Marshall Drive, Huntington, West Virginia25755, United States
| | - Laura R McCunn
- Department of Chemistry, Marshall University, 1 John Marshall Drive, Huntington, West Virginia25755, United States
| | - Carol A Parish
- Department of Chemistry, University of Richmond Gottwald Center for the Sciences, Richmond, Virginia23173, United States
| | - Xinli Song
- Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan, Hubei430071, China
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3
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Wang H, Guan J, Gao J, Li Y, Zhang J, Shan X, Wang Z. Discriminating between the dissociative photoionization and thermal decomposition products of ethylene glycol by synchrotron VUV photoionization mass spectrometry and theoretical calculations. Phys Chem Chem Phys 2022; 24:26915-26925. [DOI: 10.1039/d2cp03769f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Landscape of dissociative photoionization and thermal decompositions of ethylene glycol.
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Affiliation(s)
- Hong Wang
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, Anhui 230029, P. R. China
| | - Jiwen Guan
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, Anhui 230029, P. R. China
| | - Jiao Gao
- Dalian Institute of Chemical Physics, Dalian, 116023, P. R. China
| | - Yanbo Li
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, Anhui 230029, P. R. China
| | - Jinyang Zhang
- State Key Laboratory of Fire Science, University of Science and Technology of China, Hefei, Anhui 230026, P. R. China
| | - Xiaobin Shan
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, Anhui 230029, P. R. China
| | - Zhandong Wang
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, Anhui 230029, P. R. China
- State Key Laboratory of Fire Science, University of Science and Technology of China, Hefei, Anhui 230026, P. R. China
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4
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Sadiek I, Friedrichs G, Sakai Y. Ab Initio and RRKM/Master Equation Analysis of the Photolysis and Thermal Unimolecular Decomposition of Bromoacetaldehyde. J Phys Chem A 2021; 125:8282-8293. [PMID: 34498882 DOI: 10.1021/acs.jpca.1c04347] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Bromoacetaldehyde (BrCH2CHO) is a major stable brominated organic intermediate of the bromine-ethylene addition reaction during the arctic bromine explosion events. Similar to acetaldehyde, which has been recently identified as a source of organic acids in the troposphere, it may be subjected to photo-tautomerization initially forming brominated vinyl compounds. In this study, we investigate the unimolecular reactions of BrCH2CHO under both photolytic and thermal conditions using high-level quantum chemical calculations and Rice-Ramsperger-Kassel-Marcus (RRKM)/master equation analysis. The unimolecular decomposition of BrCH2CHO takes place through 14 dissociation and isomerization channels along a potential energy surface involving eight wells. Under the assumption of singlet ground-state potential energy surface-dominated photodynamics, the primary photodissociation yields of BrCH2CHO are investigated under both collision-free and collision energy transfer conditions. At atmospheric pressure and under tropospheric actinic flux conditions at ground level, depending on the assumed collisional energy transfer parameter, 150 cm-1 < ⟨ΔEdown⟩ < 450 cm-1, 78-33% of BrCH2CHO undergoes direct photodissociation instead of collisional deactivation at an excitation wavelength of 320 nm. This is significantly higher than the 14% reported for acetaldehyde, hence indicating a strong effect of bromine substitution on the product photolysis yield that is related to additional favorable Br and HBr forming dissociation channels. In contrast to the overall photodissociation quantum yield, the relative branching fractions of the photodissociation products are less dependent on the collisional energy transfer parameter. For a representative value of ⟨ΔEdown⟩ = 300 cm-1 and an excitation wavelength of 320 nm, with 27% for C-C bond fission, 11% for C-Br bond fission, 7% for HBr elimination, and only below 2% each for a consecutive O-Br fission reaction and the photo-tautomerization channel yielding brominated vinyl alcohol, the photodissociation is markedly different from the acetaldehyde case. Finally, as brominated halogenated compounds are of interest for flame inhibition purposes, thermal multichannel unimolecular rate constants were calculated for temperatures in the range from 500 to 2000 K. At a temperature of 2000 K and ambient pressure, the two main reaction channels are the C-Br and C-C bond fissions, contributing 35 and 43% to the total reaction flux, respectively.
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Affiliation(s)
- Ibrahim Sadiek
- Institute of Physical Chemistry, University of Kiel, 24118 Kiel, Germany.,Leibniz Institute for Plasma Science and Technology (INP), 17489 Greifswald, Germany
| | - Gernot Friedrichs
- Institute of Physical Chemistry, University of Kiel, 24118 Kiel, Germany.,KMS Kiel Marine Science-Centre for Interdisciplinary Marine Sciences, University of Kiel, 24118 Kiel, Germany
| | - Yasuyuki Sakai
- Department of Mechanical Systems Engineering, Ibaraki University, Hitachi 316-8511, Ibaraki, Japan
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5
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Kleimeier NF, Kaiser RI. Interstellar Enolization-Acetaldehyde (CH 3 CHO) and Vinyl Alcohol (H 2 CCH(OH)) as a Case Study. Chemphyschem 2021; 22:1229-1236. [PMID: 33913232 DOI: 10.1002/cphc.202100111] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Revised: 04/16/2021] [Indexed: 11/11/2022]
Abstract
Owing to the unique conditions in cold molecular clouds, enols-the thermodynamically less stable tautomers of aldehydes and ketones-do not undergo tautomerization to their more stable tautomers in the gas phase because they cannot overcome tautomerization barriers at the low temperatures. Laboratory studies of interstellar analog ices have demonstrated the formation of several keto-enol tautomer pairs in astrochemically relevant ice mixtures over the last years. However, so far only one of them, acetaldehyde-vinyl alcohol, has been detected in deep space. Due to their reactivity with electrophiles, enols can play a crucial role in our understanding of the molecular complexity in the interstellar medium and in comets and meteorites. To study the enolization of aldehydes in interstellar ices by interaction with galactic cosmic rays (GCRs), we irradiated acetaldehyde ices with energetic electrons as proxies of secondary electrons generated in the track of GCRs while penetrating interstellar ices. The results indicate that GCRs can induce enolization of acetaldehyde and that intra- as well as intermolecular processes are relevant. Therefore, enols should be ubiquitous in the interstellar medium and could be searched for using radio telescopes such as ALMA. Once enols are detected and abundances are established, they can serve as tracers for the non-equilibrium chemistry in interstellar ices thus eventually constraining fundamental reaction mechanisms deep inside interstellar ices.
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Affiliation(s)
- N Fabian Kleimeier
- Department of Chemistry and W. M. Keck Research Laboratory in Astrochemistry, University of Hawai'i at Manoa, 2545 McCarthy Mall, Honolulu, HI, 96822, USA
| | - Ralf I Kaiser
- Department of Chemistry and W. M. Keck Research Laboratory in Astrochemistry, University of Hawai'i at Manoa, 2545 McCarthy Mall, Honolulu, HI, 96822, USA
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6
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Zaleski DP, Sivaramakrishnan R, Weller HR, Seifert NA, Bross DH, Ruscic B, Moore KB, Elliott SN, Copan AV, Harding LB, Klippenstein SJ, Field RW, Prozument K. Substitution Reactions in the Pyrolysis of Acetone Revealed through a Modeling, Experiment, Theory Paradigm. J Am Chem Soc 2021; 143:3124-3142. [PMID: 33615780 DOI: 10.1021/jacs.0c11677] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The development of high-fidelity mechanisms for chemically reactive systems is a challenging process that requires the compilation of rate descriptions for a large and somewhat ill-defined set of reactions. The present unified combination of modeling, experiment, and theory provides a paradigm for improving such mechanism development efforts. Here we combine broadband rotational spectroscopy with detailed chemical modeling based on rate constants obtained from automated ab initio transition state theory-based master equation calculations and high-level thermochemical parametrizations. Broadband rotational spectroscopy offers quantitative and isomer-specific detection by which branching ratios of polar reaction products may be obtained. Using this technique, we observe and characterize products arising from H atom substitution reactions in the flash pyrolysis of acetone (CH3C(O)CH3) at a nominal temperature of 1800 K. The major product observed is ketene (CH2CO). Minor products identified include acetaldehyde (CH3CHO), propyne (CH3CCH), propene (CH2CHCH3), and water (HDO). Literature mechanisms for the pyrolysis of acetone do not adequately describe the minor products. The inclusion of a variety of substitution reactions, with rate constants and thermochemistry obtained from automated ab initio kinetics predictions and Active Thermochemical Tables analyses, demonstrates an important role for such processes. The pathway to acetaldehyde is shown to be a direct result of substitution of acetone's methyl group by a free H atom, while propene formation arises from OH substitution in the enol form of acetone by a free H atom.
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Affiliation(s)
- Daniel P Zaleski
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States.,Department of Chemistry, Colgate University, Hamilton, New York 13346, United States
| | - Raghu Sivaramakrishnan
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Hailey R Weller
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States.,Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, Tennessee 37235, United States
| | - Nathan A Seifert
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - David H Bross
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Branko Ruscic
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Kevin B Moore
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Sarah N Elliott
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Andreas V Copan
- Emmanuel College, Natural Sciences Department, Franklin Springs, Georgia 30639, United States
| | - Lawrence B Harding
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Stephen J Klippenstein
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Robert W Field
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Kirill Prozument
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
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7
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Kleimeier NF, Turner AM, Fortenberry RC, Kaiser RI. On the Formation of the Popcorn Flavorant 2,3-Butanedione (CH 3 COCOCH 3 ) in Acetaldehyde-Containing Interstellar Ices. Chemphyschem 2020; 21:1531-1540. [PMID: 32458552 DOI: 10.1002/cphc.202000116] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Revised: 05/25/2020] [Indexed: 11/06/2022]
Abstract
Acetaldehyde (CH3 CHO) is ubiquitous throughout the interstellar medium and has been observed in cold molecular clouds, star forming regions, and in meteorites such as Murchison. As the simplest methyl-bearing aldehyde, acetaldehyde constitutes a critical precursor to prebiotic molecules such as the sugar deoxyribose and amino acids via the Strecker synthesis. In this study, we reveal the first laboratory detection of 2,3-butanedione (diacetyl, CH3 COCOCH3 ) - a butter and popcorn flavorant - synthesized within acetaldehyde-based interstellar analog ices exposed to ionizing radiation at 5 K. Detailed isotopic substitution experiments combined with tunable vacuum ultraviolet (VUV) photoionization of the subliming molecules demonstrate that 2,3-butanedione is formed predominantly via the barrier-less radical-radical reaction of two acetyl radicals (CH3 ĊO). These processes are of fundamental importance for a detailed understanding of how complex organic molecules (COMs) are synthesized in deep space thus constraining the molecular structures and complexity of molecules forming in extraterrestrial ices containing acetaldehyde through a vigorous galactic cosmic ray driven non-equilibrium chemistry.
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Affiliation(s)
- N Fabian Kleimeier
- Department of Chemistry and W. M. Keck Research Laboratory in Astrochemistry, University of Hawai'i at Manoa 2545 McCarthy Mall, Honolulu, HI, 96822, USA
| | - Andrew M Turner
- Department of Chemistry and W. M. Keck Research Laboratory in Astrochemistry, University of Hawai'i at Manoa 2545 McCarthy Mall, Honolulu, HI, 96822, USA
| | - Ryan C Fortenberry
- Department of Chemistry & Biochemistry, University of Mississippi, 322 Coulter Hall, University, MS, 38677-1848, USA
| | - Ralf I Kaiser
- Department of Chemistry and W. M. Keck Research Laboratory in Astrochemistry, University of Hawai'i at Manoa 2545 McCarthy Mall, Honolulu, HI, 96822, USA
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8
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Brown GJ, Ellis MJ, Martin TD, McCunn LR. Vibrational Bands of the 2-Butyn-1-yl Radical. J Phys Chem A 2020; 124:4081-4086. [PMID: 32347722 DOI: 10.1021/acs.jpca.0c02218] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The 2-butyn-1-yl radical is an isomer of C4H5 and is structurally similar to the propargyl radical, which is the simplest resonance-stabilized hydrocarbon radical. The C4H5 radical is likely to be important to astrochemistry and combustion, similar to propargyl, yet little research has been done on its spectroscopic properties. In this work, seven vibrational bands of the 2-butyn-1-yl radical are reported. The radical was formed by pyrolysis of 1-bromo-2-butyne at 800 K and isolated in a low-temperature argon matrix. The experimentally observed frequencies and intensities of the seven vibrational bands were found to be consistent with QCISD predictions from the literature and with new B3LYP calculations in this work.
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Affiliation(s)
- Glenna J Brown
- Department of Chemistry, Marshall University, 1 John Marshall Drive, Huntington, West Virginia 25755, United States
| | - Martha J Ellis
- Department of Chemistry, Marshall University, 1 John Marshall Drive, Huntington, West Virginia 25755, United States
| | - Thaddeus D Martin
- Department of Chemistry, Marshall University, 1 John Marshall Drive, Huntington, West Virginia 25755, United States
| | - Laura R McCunn
- Department of Chemistry, Marshall University, 1 John Marshall Drive, Huntington, West Virginia 25755, United States
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9
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Hemberger P, van Bokhoven JA, Pérez-Ramírez J, Bodi A. New analytical tools for advanced mechanistic studies in catalysis: photoionization and photoelectron photoion coincidence spectroscopy. Catal Sci Technol 2020. [DOI: 10.1039/c9cy02587a] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
How can we detect reactive and elusive intermediates in catalysis to unveil reaction mechanisms? In this mini review, we discuss novel photoionization tools to support this quest.
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Affiliation(s)
- Patrick Hemberger
- Laboratory for Synchrotron Radiation and Femtochemistry
- Paul Scherrer Institute
- CH-5232 Villigen PSI
- Switzerland
| | - Jeroen A. van Bokhoven
- Laboratory for Catalysis and Sustainable Chemistry
- Paul Scherrer Institute
- CH-5232 Villigen PSI
- Switzerland
- Institute for Chemical and Bioengineering
| | - Javier Pérez-Ramírez
- Institute for Chemical and Bioengineering
- Department of Chemistry and Applied Biosciences
- ETH Zurich
- Zurich
- Switzerland
| | - Andras Bodi
- Laboratory for Synchrotron Radiation and Femtochemistry
- Paul Scherrer Institute
- CH-5232 Villigen PSI
- Switzerland
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10
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Han YC. Quasiclassical trajectory calculations of CD3CHO dissociation to CD2H + DCO on a global potential energy surface. JOURNAL OF THEORETICAL & COMPUTATIONAL CHEMISTRY 2018. [DOI: 10.1142/s0219633618500475] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
We present a quasiclassical trajectory study of the photodissociation of CD3CHO based on a global ab initio-based potential energy surface. Calculations are performed at the total energy corresponding to the photolysis wavelength of 280[Formula: see text]nm. In addition to the major radical and molecular products, CD[Formula: see text] and CD3H [Formula: see text] CO, respectively, this paper focuses on the unusual radical channel CD2H [Formula: see text] DCO, which requires a D/H exchange process before the conventional C–C bond cleavage. Five D/H exchange mechanisms are reported, which are related to the isomerizations from acetaldehyde to vinyl alcohol and back, to oxirane and back, and to the intermediate (CD–CHD–OD) and back. These D/H exchange mechanisms are in good agreement with the experimental findings [Heazlewood BR, Maccarone AT, Andrews DU, Osborn DL, Harding LB, Klippenstein SJ, Jordan MJT, Kable SH, Nat Chem 3:443, 2011].
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Affiliation(s)
- Yong-Chang Han
- Department of Physics, Dalian University of Technology, Dalian 116024, P. R. China
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11
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Saheb V, Zokaie M. Multichannel Gas-Phase Unimolecular Decomposition of Acetone: Theoretical Kinetic Studies. J Phys Chem A 2018; 122:5895-5904. [DOI: 10.1021/acs.jpca.8b02423] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Vahid Saheb
- Department of Chemistry, Shahid Bahonar University of Kerman, Kerman 76169-14111, Iran
| | - Meymanat Zokaie
- Department of Chemistry, Shahid Bahonar University of Kerman, Kerman 76169-14111, Iran
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12
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Ormond TK, Baraban JH, Porterfield JP, Scheer AM, Hemberger P, Troy TP, Ahmed M, Nimlos MR, Robichaud DJ, Daily JW, Ellison GB. Thermal Decompositions of the Lignin Model Compounds: Salicylaldehyde and Catechol. J Phys Chem A 2018; 122:5911-5924. [DOI: 10.1021/acs.jpca.8b03201] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
- Thomas K. Ormond
- National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, Colorado 80401, United States
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309-0215, United States
| | - Joshua H. Baraban
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309-0215, United States
| | - Jessica P. Porterfield
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309-0215, United States
| | - Adam M. Scheer
- Combustion Research Facility, Sandia National Laboratory, PO Box 969, Livermore, California 94551-0969, United States
| | - Patrick Hemberger
- Laboratory for Femtochemistry and Synchrotron Radiation, Paul Scherrer Institute, CH-5234 Villigen-PSI, Switzerland
| | - Tyler P. Troy
- Chemical Sciences Division, Lawrence Berkeley National Laboratories, Berkeley, California 94720, United States
| | - Musahid Ahmed
- Chemical Sciences Division, Lawrence Berkeley National Laboratories, Berkeley, California 94720, United States
| | - Mark R. Nimlos
- National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, Colorado 80401, United States
| | - David J. Robichaud
- National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, Colorado 80401, United States
| | - John W. Daily
- Center for Combustion and Environmental Research, Department of Mechanical Engineering, University of Colorado, Boulder, Colorado 80309-0427, United States
| | - G. Barney Ellison
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309-0215, United States
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13
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Zhao L, Kaiser RI, Xu B, Ablikim U, Ahmed M, Zagidullin MV, Azyazov VN, Howlader AH, Wnuk SF, Mebel AM. VUV Photoionization Study of the Formation of the Simplest Polycyclic Aromatic Hydrocarbon: Naphthalene (C 10H 8). J Phys Chem Lett 2018; 9:2620-2626. [PMID: 29717871 DOI: 10.1021/acs.jpclett.8b01020] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The formation of the simplest polycyclic aromatic hydrocarbon (PAH), naphthalene (C10H8), was explored in a high-temperature chemical reactor under combustion-like conditions in the phenyl (C6H5)-vinylacetylene (C4H4) system. The products were probed utilizing tunable vacuum ultraviolet light by scanning the photoionization efficiency (PIE) curve at a mass-to-charge m/ z = 128 (C10H8+) of molecules entrained in a molecular beam. The data fitting with PIE reference curves of naphthalene, 4-phenylvinylacetylene (C6H5CCC2H3), and trans-1-phenylvinylacetylene (C6H5CHCHCCH) indicates that the isomers were generated with branching ratios of 43.5±9.0 : 6.5±1.0 : 50.0±10.0%. Kinetics simulations agree nicely with the experimental findings with naphthalene synthesized via the hydrogen abstraction-vinylacetylene addition (HAVA) pathway and through hydrogen-assisted isomerization of phenylvinylacetylenes. The HAVA route to naphthalene at elevated temperatures represents an alternative pathway to the hydrogen abstraction-acetylene addition (HACA) forming naphthalene in flames and circumstellar envelopes, whereas in cold molecular clouds, HAVA synthesizes naphthalene via a barrierless bimolecular route.
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Affiliation(s)
- Long Zhao
- Department of Chemistry , University of Hawaii at Manoa , Honolulu , Hawaii 96822 , United States
| | - Ralf I Kaiser
- Department of Chemistry , University of Hawaii at Manoa , Honolulu , Hawaii 96822 , United States
| | - Bo Xu
- Chemical Sciences Division , Lawrence Berkeley National Laboratory , Berkeley , California 94720 , United States
| | - Utuq Ablikim
- Chemical Sciences Division , Lawrence Berkeley National Laboratory , Berkeley , California 94720 , United States
| | - Musahid Ahmed
- Chemical Sciences Division , Lawrence Berkeley National Laboratory , Berkeley , California 94720 , United States
| | - Marsel V Zagidullin
- Samara National Research University , Samara 443086 , Russia
- Lebedev Physical Institute , Samara 443011 , Russia
| | - Valeriy N Azyazov
- Samara National Research University , Samara 443086 , Russia
- Lebedev Physical Institute , Samara 443011 , Russia
| | - A Hasan Howlader
- Department of Chemistry and Biochemistry , Florida International University , Miami , Florida 33199 , United States
| | - Stanislaw F Wnuk
- Department of Chemistry and Biochemistry , Florida International University , Miami , Florida 33199 , United States
| | - Alexander M Mebel
- Department of Chemistry and Biochemistry , Florida International University , Miami , Florida 33199 , United States
- Samara National Research University , Samara 443086 , Russia
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14
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Saheb V, Hashemi SR, Hosseini SMA. Theoretical Studies on the Kinetics of Multi-Channel Gas-Phase Unimolecular Decomposition of Acetaldehyde. J Phys Chem A 2017; 121:6887-6895. [PMID: 28825298 DOI: 10.1021/acs.jpca.7b04771] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Theoretical kinetic studies are performed on the multichannel thermal decomposition of acetaldehyde. The geometries of the stationary points on the potential energy surface of the reaction are optimized at the MP2(full)/6-311++G(2d,2p) level of theory. More accurate energies are obtained by single point energy calculations at the CCSD(T,full)/augh-cc-pVTZ+2df, CBS-Q and G4 levels of theory. Here, by application of steady-state approximation to the thermally activated species CH3CHO* and CH2CHOH* and performance of statistical mechanical manipulations, expressions for the rate constants for different product channels are derived. Special attempts are made to compute accurate energy-specific rate coefficients for different channels by using semiclassical transition state theory. It is found that the isomerization of CH3CHO to the enol-form CH2CHOH plays a significant role in the unimolecular reaction of CH3CHO. The possible products of the reaction are formed via unimolecular decomposition of CH3CHO and CH2CHOH. The computed rate coefficients reveal that the dominant channel at low temperatures and high pressures is the formation of CH2CHOH due to the low barrier height for CH3CHO → CH2CHOH isomerization process. However, at high temperatures, the product channel CH3 + CHO becomes dominant.
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Affiliation(s)
- Vahid Saheb
- Department of Chemistry, Shahid Bahonar University of Kerman , Kerman 76169, Iran
| | - S Rasoul Hashemi
- Department of Chemistry, Shahid Bahonar University of Kerman , Kerman 76169, Iran
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15
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Couch DE, Buckingham GT, Baraban JH, Porterfield JP, Wooldridge LA, Ellison GB, Kapteyn HC, Murnane MM, Peters WK. Tabletop Femtosecond VUV Photoionization and PEPICO Detection of Microreactor Pyrolysis Products. J Phys Chem A 2017; 121:5280-5289. [DOI: 10.1021/acs.jpca.7b02821] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- David E. Couch
- JILA and Department of Physics, University of Colorado, Boulder, Colorado 80309, United States
| | - Grant T. Buckingham
- Department
of Chemistry, University of Colorado, Boulder, Colorado 80309, United States
| | - Joshua H. Baraban
- Department
of Chemistry, University of Colorado, Boulder, Colorado 80309, United States
| | | | - Laura A. Wooldridge
- JILA and Department of Physics, University of Colorado, Boulder, Colorado 80309, United States
| | - G. Barney Ellison
- Department
of Chemistry, University of Colorado, Boulder, Colorado 80309, United States
| | - Henry C. Kapteyn
- JILA and Department of Physics, University of Colorado, Boulder, Colorado 80309, United States
| | - Margaret M. Murnane
- JILA and Department of Physics, University of Colorado, Boulder, Colorado 80309, United States
| | - William K. Peters
- JILA and Department of Physics, University of Colorado, Boulder, Colorado 80309, United States
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16
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Vasiliou AK, Anderson DE, Cowell TW, Kong J, Melhado WF, Phillips MD, Whitman JC. Thermal Decomposition Mechanism for Ethanethiol. J Phys Chem A 2017; 121:4953-4960. [PMID: 28558212 DOI: 10.1021/acs.jpca.7b02629] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The thermal decomposition of ethanethiol was studied using a 1 mm × 2 cm pulsed silicon carbide microtubular reactor, CH3CH2SH + Δ → Products. Unlike previous studies these experiments were able to identify the initial ethanethiol decomposition products. Ethanethiol was entrained in either an Ar or a He carrier gas, passed through a heated (300-1700 K) SiC microtubular reactor (roughly ≤100 μs residence time) and exited into a vacuum chamber. Within one reactor diameter the gas cools to less than 50 K rotationally, and all reactions cease. The resultant molecular beam was probed by photoionization mass spectroscopy and IR spectroscopy. Ethanethiol was found to undergo unimolecular decomposition by three pathways: CH3CH2SH → (1) CH3CH2 + SH, (2) CH3 + H2C═S, and (3) H2C═CH2 + H2S. The experimental findings are in good agreement with electronic structure calculations.
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Affiliation(s)
- AnGayle K Vasiliou
- Department of Chemistry and Biochemistry, Middlebury College , Middlebury, Vermont 05753, United States
| | - Daniel E Anderson
- Department of Chemistry and Biochemistry, Middlebury College , Middlebury, Vermont 05753, United States
| | - Thomas W Cowell
- Department of Chemistry and Biochemistry, Middlebury College , Middlebury, Vermont 05753, United States
| | - Jessica Kong
- Department of Chemistry and Biochemistry, Middlebury College , Middlebury, Vermont 05753, United States
| | - William F Melhado
- Department of Chemistry and Biochemistry, Middlebury College , Middlebury, Vermont 05753, United States
| | - Margaret D Phillips
- Department of Chemistry and Biochemistry, Middlebury College , Middlebury, Vermont 05753, United States
| | - Jared C Whitman
- Department of Chemistry and Biochemistry, Middlebury College , Middlebury, Vermont 05753, United States
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17
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Porterfield JP, Bross DH, Ruscic B, Thorpe JH, Nguyen TL, Baraban JH, Stanton JF, Daily JW, Ellison GB. Thermal Decomposition of Potential Ester Biofuels. Part I: Methyl Acetate and Methyl Butanoate. J Phys Chem A 2017; 121:4658-4677. [PMID: 28517940 DOI: 10.1021/acs.jpca.7b02639] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Two methyl esters were examined as models for the pyrolysis of biofuels. Dilute samples (0.06-0.13%) of methyl acetate (CH3COOCH3) and methyl butanoate (CH3CH2CH2COOCH3) were entrained in (He, Ar) carrier gas and decomposed in a set of flash-pyrolysis microreactors. The pyrolysis products resulting from the methyl esters were detected and identified by vacuum ultraviolet photoionization mass spectrometry. Complementary product identification was provided by matrix infrared absorption spectroscopy. Pyrolysis pressures in the pulsed microreactor were about 20 Torr and residence times through the reactors were roughly 25-150 μs. Reactor temperatures of 300-1600 K were explored. Decomposition of CH3COOCH3 commences at 1000 K, and the initial products are (CH2═C═O and CH3OH). As the microreactor is heated to 1300 K, a mixture of CH2═C═O and CH3OH, CH3, CH2═O, H, CO, and CO2 appears. The thermal cracking of CH3CH2CH2COOCH3 begins at 800 K with the formation of CH3CH2CH═C═O and CH3OH. By 1300 K, the pyrolysis of methyl butanoate yields a complex mixture of CH3CH2CH═C═O, CH3OH, CH3, CH2═O, CO, CO2, CH3CH═CH2, CH2CHCH2, CH2═C═CH2, HCCCH2, CH2═C═C═O, CH2═CH2, HC≡CH, and CH2═C═O. On the basis of the results from the thermal cracking of methyl acetate and methyl butanoate, we predict several important decomposition channels for the pyrolysis of fatty acid methyl esters, R-CH2-COOCH3. The lowest-energy fragmentation will be a 4-center elimination of methanol to form the ketene RCH═C═O. At higher temperatures, concerted fragmentation to radicals will ensue to produce a mixture of species: (RCH2 + CO2 + CH3) and (RCH2 + CO + CH2═O + H). Thermal cracking of the β C-C bond of the methyl ester will generate the radicals (R and H) as well as CH2═C═O + CH2═O. The thermochemistry of methyl acetate and its fragmentation products were obtained via the Active Thermochemical Tables (ATcT) approach, resulting in ΔfH298(CH3COOCH3) = -98.7 ± 0.2 kcal mol-1, ΔfH298(CH3CO2) = -45.7 ± 0.3 kcal mol-1, and ΔfH298(COOCH3) = -38.3 ± 0.4 kcal mol-1.
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Affiliation(s)
| | - David H Bross
- Chemical Sciences and Engineering Division, Argonne National Laboratory , Argonne, Illinois 60439, United States
| | - Branko Ruscic
- Chemical Sciences and Engineering Division, Argonne National Laboratory , Argonne, Illinois 60439, United States.,Computation Institute, The University of Chicago , Chicago, Illinois 60637, United States
| | - James H Thorpe
- Department of Chemistry, University of Texas , Austin, Texas 78712, United States
| | - Thanh Lam Nguyen
- Department of Chemistry, University of Texas , Austin, Texas 78712, United States
| | | | - John F Stanton
- Department of Chemistry, University of Texas , Austin, Texas 78712, United States.,Department of Chemistry, University of Florida , Gainesville, Florida 32611, United States
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18
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Wang Y, Tang Y, Shao Y. Theoretical investigation on the reaction of Methylidyne Radical (CH) with acetaldehyde (CH 3 CHO). COMPUT THEOR CHEM 2017. [DOI: 10.1016/j.comptc.2017.01.029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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19
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Buckingham GT, Porterfield JP, Kostko O, Troy TP, Ahmed M, Robichaud DJ, Nimlos MR, Daily JW, Ellison GB. The thermal decomposition of the benzyl radical in a heated micro-reactor. II. Pyrolysis of the tropyl radical. J Chem Phys 2016; 145:014305. [DOI: 10.1063/1.4954895] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Grant T. Buckingham
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309-0215, USA
- National Bioenergy Center, National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden Colorado 80401, USA
| | - Jessica P. Porterfield
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309-0215, USA
| | - Oleg Kostko
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Tyler P. Troy
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Musahid Ahmed
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - David J. Robichaud
- National Bioenergy Center, National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden Colorado 80401, USA
| | - Mark R. Nimlos
- National Bioenergy Center, National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden Colorado 80401, USA
| | - John W. Daily
- Department of Mechanical Engineering, Center for Combustion and Environmental Research, University of Colorado, Boulder, Colorado 80309-0427, USA
| | - G. Barney Ellison
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309-0215, USA
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20
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Kostko O, Bandyopadhyay B, Ahmed M. Vacuum Ultraviolet Photoionization of Complex Chemical Systems. Annu Rev Phys Chem 2016; 67:19-40. [DOI: 10.1146/annurev-physchem-040215-112553] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Oleg Kostko
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720;
| | - Biswajit Bandyopadhyay
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720;
| | - Musahid Ahmed
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720;
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21
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Arruda MS, Medina A, Sousa JN, Mendes LAV, Marinho RRT, Prudente FV. Communication: Protonation process of formic acid from the ionization and fragmentation of dimers induced by synchrotron radiation in the valence region. J Chem Phys 2016; 144:141101. [PMID: 27083700 DOI: 10.1063/1.4945807] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The ionization and fragmentation of monomers of organic molecules have been extensively studied in the gas phase using mass spectroscopy. In the spectra of these molecules it is possible to identify the presence of protonated cations, which have a mass-to-charge ratio one unit larger than the parent ion. In this work, we investigate this protonation process as a result of dimers photofragmentation. Experimental photoionization and photofragmentation results of doubly deuterated formic acid (DCOOD) in the gas phase by photons in the vacuum ultraviolet region are presented. The experiment was performed by using a time-of-flight mass spectrometer installed at the Brazilian Synchrotron Light Laboratory and spectra for different pressure values in the experimental chamber were obtained. The coupled cluster approach with single and double substitutions was employed to assist the experimental analysis. Results indicate that protonated formic acid ions are originated from dimer dissociation, and the threshold photoionization of (DCOOD)⋅D(+) is also determined.
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Affiliation(s)
- Manuela S Arruda
- Instituto de Física, Universidade Federal da Bahia, 40170-115 Salvador, BA, Brazil
| | - Aline Medina
- Instituto de Física, Universidade Federal da Bahia, 40170-115 Salvador, BA, Brazil
| | - Josenilton N Sousa
- Instituto de Física, Universidade Federal da Bahia, 40170-115 Salvador, BA, Brazil
| | - Luiz A V Mendes
- Instituto de Física, Universidade Federal da Bahia, 40170-115 Salvador, BA, Brazil
| | - Ricardo R T Marinho
- Instituto de Física, Universidade Federal da Bahia, 40170-115 Salvador, BA, Brazil
| | - Frederico V Prudente
- Instituto de Física, Universidade Federal da Bahia, 40170-115 Salvador, BA, Brazil
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22
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Porterfield JP, Baraban JH, Troy TP, Ahmed M, McCarthy MC, Morgan KM, Daily JW, Nguyen TL, Stanton JF, Ellison GB. Pyrolysis of the Simplest Carbohydrate, Glycolaldehyde (CHO−CH2OH), and Glyoxal in a Heated Microreactor. J Phys Chem A 2016; 120:2161-72. [DOI: 10.1021/acs.jpca.6b00652] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
| | | | - Tyler P. Troy
- Chemical
Sciences Division, Lawrence Berkeley National Laboratories, Berkeley, California 94720, United States
| | - Musahid Ahmed
- Chemical
Sciences Division, Lawrence Berkeley National Laboratories, Berkeley, California 94720, United States
| | - Michael C. McCarthy
- Harvard-Smithsonian Center for Astrophysics, Cambridge, Massachusetts 02138, United States
| | - Kathleen M. Morgan
- Department
of Chemistry, Xavier University of Louisiana, New Orleans, Louisiana 70125-1098, United States
| | | | - Thanh Lam Nguyen
- Department
of Chemistry, University of Texas at Austin, Austin, Texas 78712, United States
| | - John F. Stanton
- Department
of Chemistry, University of Texas at Austin, Austin, Texas 78712, United States
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23
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Urness KN, Guan Q, Troy TP, Ahmed M, Daily JW, Ellison GB, Simmie JM. Pyrolysis Pathways of the Furanic Ether 2-Methoxyfuran. J Phys Chem A 2015; 119:9962-77. [PMID: 26351733 DOI: 10.1021/acs.jpca.5b06779] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Substituted furans, including furanic ethers, derived from nonedible biomass have been proposed as second-generation biofuels. In order to use these molecules as fuels, it is important to understand how they break apart thermally. In this work, a series of experiments were conducted to study the unimolecular and low-pressure bimolecular decomposition mechanisms of the smallest furanic ether, 2-methoxyfuran. Electronic structure (CBS-QB3) calculations indicate this substituted furan has an unusually weak O-CH3 bond, approximately 190 kJ mol(-1) (45 kcal mol(-1)); thus, the primary decomposition pathway is through bond scission resulting in CH3 and 2-furanyloxy (O-C4H3O) radicals. Final products from the ring opening of the furanyloxy radical include 2 CO, HC≡CH, and H. The decomposition of methoxyfuran is studied over a range of concentrations (0.0025-0.1%) in helium or argon in a heated silicon carbide (SiC) microtubular flow reactor (0.66-1 mm i.d., 2.5-3.5 cm long) with reactor wall temperatures from 300 to 1300 K. Inlet pressures to the reactor are 150-1500 Torr, and the gas mixture emerges as a skimmed molecular beam at a pressure of approximately 10 μTorr. Products formed at early pyrolysis times (100 μs) are detected by 118.2 nm (10.487 eV) photoionization mass spectrometry (PIMS), tunable synchrotron VUV PIMS, and matrix infrared absorption spectroscopy. Secondary products resulting from H or CH3 addition to the parent and reaction with 2-furanyloxy were also observed and include CH2═CH-CHO, CH3-CH═CH-CHO, CH3-CO-CH═CH2, and furanones; under the conditions in the reactor, we estimate these reactions contribute to at most 1-3% of total methoxyfuran decomposition. This work also includes observation and characterization of an allylic lactone radical, 2-furanyloxy (O-C4H3O), with the assignment of several intense vibrational bands in an Ar matrix, an estimate of the ionization threshold, and photoionization efficiency. A pressure-dependent kinetic mechanism is also developed to model the decomposition behavior of methoxyfuran and provide pathways for the minor bimolecular reaction channels that are observed experimentally.
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Affiliation(s)
- Kimberly N Urness
- Department of Mechanical Engineering, University of Colorado , Boulder, Colorado 80309-0427, United States
| | - Qi Guan
- Department of Mechanical Engineering, University of Colorado , Boulder, Colorado 80309-0427, United States
| | - Tyler P Troy
- Chemical Sciences Division, Lawrence Berkeley National Laboratory , MS 6R-2100, Berkeley, California 94720, United States
| | - Musahid Ahmed
- Chemical Sciences Division, Lawrence Berkeley National Laboratory , MS 6R-2100, Berkeley, California 94720, United States
| | - John W Daily
- Department of Mechanical Engineering, University of Colorado , Boulder, Colorado 80309-0427, United States
| | - G Barney Ellison
- Department of Chemistry and Biochemistry, University of Colorado , Boulder, Colorado 80309-0215, United States
| | - John M Simmie
- Combustion Chemistry Centre, School of Chemistry, National University of Ireland , Galway, Ireland
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24
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Wright EM, Warner BJ, Foreman HE, McCunn LR, Urness KN. Pyrolysis Reactions of 3-Oxetanone. J Phys Chem A 2015; 119:7966-72. [PMID: 26103787 DOI: 10.1021/acs.jpca.5b04565] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The pyrolysis products of gas-phase 3-oxetanone were identified via matrix-isolation Fourier transform infrared spectroscopy and photoionization mass spectrometry. Pyrolysis was conducted in a hyperthermal nozzle at temperatures from 100 to 1200 °C with the dissociation onset observed at ∼600 °C. The ring strain in the cyclic structure of 3-oxetanone causes the molecule to decompose at relatively low temperatures. Previously, only one dissociation channel, producing formaldehyde and ketene, was considered as significant in photolysis. This study presents the first experimental measurements of the thermal decomposition of 3-oxetanone demonstrating an additional dissociation channel that forms ethylene oxide and carbon monoxide. Major products include formaldehyde, ketene, carbon monoxide, ethylene oxide, ethylene, and methyl radical. The first four products stem from initial decomposition of 3-oxetanone, while the additional products, ethylene and methyl radical, are believed to be due to further reactions involving ethylene oxide.
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Affiliation(s)
- Emily M Wright
- Department of Chemistry, Marshall University, One John Marshall Drive, Huntington, West Virginia 25755, United States.,Department of Mechanical Engineering, University of Colorado, Boulder, Colorado 80309, United States
| | - Brian J Warner
- Department of Chemistry, Marshall University, One John Marshall Drive, Huntington, West Virginia 25755, United States.,Department of Mechanical Engineering, University of Colorado, Boulder, Colorado 80309, United States
| | - Hannah E Foreman
- Department of Chemistry, Marshall University, One John Marshall Drive, Huntington, West Virginia 25755, United States.,Department of Mechanical Engineering, University of Colorado, Boulder, Colorado 80309, United States
| | - Laura R McCunn
- Department of Chemistry, Marshall University, One John Marshall Drive, Huntington, West Virginia 25755, United States.,Department of Mechanical Engineering, University of Colorado, Boulder, Colorado 80309, United States
| | - Kimberly N Urness
- Department of Chemistry, Marshall University, One John Marshall Drive, Huntington, West Virginia 25755, United States.,Department of Mechanical Engineering, University of Colorado, Boulder, Colorado 80309, United States
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25
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Prozument K, Barratt Park G, Shaver RG, Vasiliou AK, Oldham JM, David DE, Muenter JS, Stanton JF, Suits AG, Barney Ellison G, Field RW. Chirped-Pulse millimeter-Wave spectroscopy for dynamics and kinetics studies of pyrolysis reactions. Phys Chem Chem Phys 2015; 16:15739-15751. [PMID: 24756159 DOI: 10.1039/c3cp55352c] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A Chirped-Pulse millimeter-Wave (CPmmW) spectrometer is applied to the study of chemical reaction products that result from pyrolysis in a Chen nozzle heated to 1000-1800 K. Millimeter-wave rotational spectroscopy unambiguously determines, for each polar reaction product, the species, the conformers, relative concentrations, conversion percentage from precursor to each product, and, in some cases, vibrational state population distributions. A chirped-pulse spectrometer can, within the frequency range of a single chirp, sample spectral regions of up to ∼10 GHz and simultaneously detect many reaction products. Here we introduce a modification to the CPmmW technique in which multiple chirps of different spectral content are applied to a molecular beam pulse that contains the pyrolysis reaction products. This technique allows for controlled allocation of its sensitivity to specific molecular transitions and effectively doubles the bandwidth of the spectrometer. As an example, the pyrolysis reaction of ethyl nitrite, CH3CH2ONO, is studied, and CH3CHO, H2CO, and HNO products are simultaneously observed and quantified, exploiting the multi-chirp CPmmW technique. Rotational and vibrational temperatures of some product molecules are determined. Subsequent to supersonic expansion from the heated nozzle, acetaldehyde molecules display a rotational temperature of 4 ± 1 K. Vibrational temperatures are found to be controlled by the collisional cooling in the expansion, and to be both species- and vibrational mode-dependent. Rotational transitions of vibrationally excited formaldehyde in levels ν4, 2ν4, 3ν4, ν2, ν3, and ν6 are observed and effective vibrational temperatures for modes 2, 3, 4, and 6 are determined and discussed.
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Affiliation(s)
- Kirill Prozument
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Ave, Cambridge, MA 02139, USA. and Department of Chemistry, Wayne State University, 5101 Cass Ave, Detroit, MI 48202, USA
| | - G Barratt Park
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Ave, Cambridge, MA 02139, USA.
| | - Rachel G Shaver
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Ave, Cambridge, MA 02139, USA.
| | - AnGayle K Vasiliou
- Department of Chemistry and Biochemistry, Middlebury College, 276 Bicentennial Way, Middlebury, VT 05753, USA
| | - James M Oldham
- Department of Chemistry, Wayne State University, 5101 Cass Ave, Detroit, MI 48202, USA
| | - Donald E David
- Department of Chemistry and Biochemistry, University of Colorado at Boulder, Cristol Chemistry 58, Boulder, CO 80309, USA
| | - John S Muenter
- Department of Chemistry, University of Rochester, 120 Trustee Road, Rochester, NY 14627, USA
| | - John F Stanton
- Department of Chemistry, The University of Texas at Austin, 1 University Station A5300, Austin, TX 78712-0165, USA
| | - Arthur G Suits
- Department of Chemistry, Wayne State University, 5101 Cass Ave, Detroit, MI 48202, USA
| | - G Barney Ellison
- Department of Chemistry and Biochemistry, University of Colorado at Boulder, Cristol Chemistry 58, Boulder, CO 80309, USA
| | - Robert W Field
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Ave, Cambridge, MA 02139, USA.
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26
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Sivaramakrishnan R, Michael JV, Harding LB, Klippenstein SJ. Resolving Some Paradoxes in the Thermal Decomposition Mechanism of Acetaldehyde. J Phys Chem A 2015; 119:7724-33. [DOI: 10.1021/acs.jpca.5b01032] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Raghu Sivaramakrishnan
- Chemical Sciences & Engineering Division, Argonne National Laboratory, Argonne, Illinois 60439, United States
| | - Joe V. Michael
- Chemical Sciences & Engineering Division, Argonne National Laboratory, Argonne, Illinois 60439, United States
| | - Lawrence B. Harding
- Chemical Sciences & Engineering Division, Argonne National Laboratory, Argonne, Illinois 60439, United States
| | - Stephen J. Klippenstein
- Chemical Sciences & Engineering Division, Argonne National Laboratory, Argonne, Illinois 60439, United States
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27
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Warner BJ, Wright EM, Foreman HE, Wellman CD, McCunn LR. Products from pyrolysis of gas-phase propionaldehyde. J Phys Chem A 2015; 119:14-23. [PMID: 25526259 DOI: 10.1021/jp5077802] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A hyperthermal nozzle was utilized to study the thermal decomposition of propionaldehyde, CH3CH2CHO, over a temperature range of 1073-1600 K. Products were identified with two detection methods: matrix-isolation Fourier transform infrared spectroscopy and photoionization mass spectrometry. Evidence was observed for four reactions during the breakdown of propionaldehyde: α-C-C bond scission yielding CH3CH2, CO, and H, an elimination reaction forming methylketene and H2, an isomerization pathway leading to propyne via the elimination of H2O, and a β-C-C bond scission channel forming methyl radical and (•)CH2CHO. The products identified during this experiment were CO, HCO, CH3CH2, CH3CH═C═O, H2O, CH3C≡CH, CH3, H2C═C═O, CH2CH2, CH3CH═CH2, HC≡CH, CH2CCH, H2CO, C4H2, C4H4, and CH3CHO. The first eight products result from primary or bimolecular reactions involving propionaldehyde while the remaining products occur from reactions including the initial pyrolysis products. While the pyrolysis of propionaldehyde involves reactions similar to those observed for acetaldehyde and butyraldehyde in recent studies, there are a few unique products observed which highlight the need for further study of the pyrolysis mechanism.
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Affiliation(s)
- Brian J Warner
- Department of Chemistry, Marshall University , One John Marshall Drive, Huntington, West Virginia 25755, United States
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28
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Prozument K, Suleimanov YV, Buesser B, Oldham JM, Green WH, Suits AG, Field RW. A Signature of Roaming Dynamics in the Thermal Decomposition of Ethyl Nitrite: Chirped-Pulse Rotational Spectroscopy and Kinetic Modeling. J Phys Chem Lett 2014; 5:3641-3648. [PMID: 26278732 DOI: 10.1021/jz501758p] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Chirped-pulse (CP) Fourier transform rotational spectroscopy is uniquely suited for near-universal quantitative detection and structural characterization of mixtures that contain multiple molecular and radical species. In this work, we employ CP spectroscopy to measure product branching and extract information about the reaction mechanism, guided by kinetic modeling. Pyrolysis of ethyl nitrite, CH3CH2ONO, is studied in a Chen type flash pyrolysis reactor at temperatures of 1000-1800 K. The branching between HNO, CH2O, and CH3CHO products is measured and compared to the kinetic models generated by the Reaction Mechanism Generator software. We find that roaming CH3CH2ONO → CH3CHO + HNO plays an important role in the thermal decomposition of ethyl nitrite, with its rate, at 1000 K, comparable to that of the radical elimination channel CH3CH2ONO → CH3CH2O + NO. HNO is a signature of roaming in this system.
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Affiliation(s)
| | | | - Beat Buesser
- §IBM Research, Smarter Cities Technology Centre, Dublin 15, Ireland
| | - James M Oldham
- ∥Department of Chemistry, Wayne State University, Detroit, Michigan 48202, United States
| | | | - Arthur G Suits
- ∥Department of Chemistry, Wayne State University, Detroit, Michigan 48202, United States
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29
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Guan Q, Urness KN, Ormond TK, David DE, Barney Ellison G, Daily JW. The properties of a micro-reactor for the study of the unimolecular decomposition of large molecules. INT REV PHYS CHEM 2014. [DOI: 10.1080/0144235x.2014.967951] [Citation(s) in RCA: 94] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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30
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Kidwell NM, Vaquero-Vara V, Ormond TK, Buckingham GT, Zhang D, Mehta-Hurt DN, McCaslin L, Nimlos MR, Daily JW, Dian BC, Stanton JF, Ellison GB, Zwier TS. Chirped-Pulse Fourier Transform Microwave Spectroscopy Coupled with a Flash Pyrolysis Microreactor: Structural Determination of the Reactive Intermediate Cyclopentadienone. J Phys Chem Lett 2014; 5:2201-2207. [PMID: 26279534 DOI: 10.1021/jz5010895] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Chirped-pulse Fourier transform microwave spectroscopy (CP-FTMW) is combined with a flash pyrolysis (hyperthermal) microreactor as a novel method to investigate the molecular structure of cyclopentadienone (C5H4═O), a key reactive intermediate in biomass decomposition and aromatic oxidation. Samples of C5H4═O were generated cleanly from the pyrolysis of o-phenylene sulfite and cooled in a supersonic expansion. The (13)C isotopic species were observed in natural abundance in both C5H4═O and in C5D4═O samples, allowing precise measurement of the heavy atom positions in C5H4═O. The eight isotopomers include: C5H4═O, C5D4═O, and the singly (13)C isotopomers with (13)C substitution at the C1, C2, and C3 positions. Microwave spectra were interpreted by CCSD(T) ab initio electronic structure calculations and an re molecular structure for C5H4═O was found. Comparisons of the structure of this "anti-aromatic" molecule are made with those of comparable organic molecules, and it is concluded that the disfavoring of the "anti-aromatic" zwitterionic resonance structure is consistent with a more pronounced C═C/C-C bond alternation.
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Affiliation(s)
- Nathanael M Kidwell
- †Department of Chemistry, Purdue University, West Lafayette, Indiana 47907-2084, United States
| | - Vanesa Vaquero-Vara
- †Department of Chemistry, Purdue University, West Lafayette, Indiana 47907-2084, United States
| | - Thomas K Ormond
- ‡National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, Colorado 80401, United States
- ∥Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309-0215, United States
| | - Grant T Buckingham
- ‡National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, Colorado 80401, United States
- ∥Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309-0215, United States
| | - Di Zhang
- †Department of Chemistry, Purdue University, West Lafayette, Indiana 47907-2084, United States
| | - Deepali N Mehta-Hurt
- †Department of Chemistry, Purdue University, West Lafayette, Indiana 47907-2084, United States
| | - Laura McCaslin
- ¶Institute of Theoretical Chemistry, Department of Chemistry, University of Texas, Austin, Texas 78712, United States
| | - Mark R Nimlos
- ‡National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, Colorado 80401, United States
| | - John W Daily
- ⊥Center for Combustion and Environmental Research, Department of Mechanical Engineering, University of Colorado, Boulder, Colorado 80309-0427, United States
| | - Brian C Dian
- †Department of Chemistry, Purdue University, West Lafayette, Indiana 47907-2084, United States
| | - John F Stanton
- ¶Institute of Theoretical Chemistry, Department of Chemistry, University of Texas, Austin, Texas 78712, United States
| | - G Barney Ellison
- ∥Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309-0215, United States
| | - Timothy S Zwier
- †Department of Chemistry, Purdue University, West Lafayette, Indiana 47907-2084, United States
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Custodis VBF, Hemberger P, Ma Z, van Bokhoven JA. Mechanism of Fast Pyrolysis of Lignin: Studying Model Compounds. J Phys Chem B 2014; 118:8524-31. [DOI: 10.1021/jp5036579] [Citation(s) in RCA: 106] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Victoria B. F. Custodis
- Department
of Chemistry and Applied Biosciences, Institute for Chemical and Bioengineering, ETH Zurich, HCI E 127, Vladimir-Prelog-Weg 1, 8093 Zurich, Switzerland
| | - Patrick Hemberger
- Molecular
Dynamics Group, Paul Scherrer Institute, CH-5232 Villigen-PSI, Switzerland
| | - Zhiqiang Ma
- Department
of Chemistry and Applied Biosciences, Institute for Chemical and Bioengineering, ETH Zurich, HCI E 127, Vladimir-Prelog-Weg 1, 8093 Zurich, Switzerland
| | - Jeroen A. van Bokhoven
- Department
of Chemistry and Applied Biosciences, Institute for Chemical and Bioengineering, ETH Zurich, HCI E 127, Vladimir-Prelog-Weg 1, 8093 Zurich, Switzerland
- Laboratory
for Catalysis and Sustainable Chemistry, Paul Scherrer Institute, WLGA 135, 5232 Villigen, Switzerland
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Urness KN, Guan Q, Golan A, Daily JW, Nimlos MR, Stanton JF, Ahmed M, Ellison GB. Pyrolysis of furan in a microreactor. J Chem Phys 2014; 139:124305. [PMID: 24089765 DOI: 10.1063/1.4821600] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
A silicon carbide microtubular reactor has been used to measure branching ratios in the thermal decomposition of furan, C4H4O. The pyrolysis experiments are carried out by passing a dilute mixture of furan (approximately 0.01%) entrained in a stream of helium through the heated reactor. The SiC reactor (0.66 mm i.d., 2 mm o.d., 2.5 cm long) operates with continuous flow. Experiments were performed with a reactor inlet pressure of 100-300 Torr and a wall temperature between 1200 and 1600 K; characteristic residence times in the reactor are 60-150 μs. The unimolecular decomposition pathway of furan is confirmed to be: furan (+ M) ⇌ α-carbene or β-carbene. The α-carbene fragments to CH2=C=O + HC≡CH while the β-carbene isomerizes to CH2=C=CHCHO. The formyl allene can isomerize to CO + CH3C≡CH or it can fragment to H + CO + HCCCH2. Tunable synchrotron radiation photoionization mass spectrometry is used to monitor the products and to measure the branching ratio of the two carbenes as well as the ratio of [HCCCH2]/[CH3C≡CH]. The results of these pyrolysis experiments demonstrate a preference for 80%-90% of furan decomposition to occur via the β-carbene. For reactor temperatures of 1200-1400 K, no propargyl radicals are formed. As the temperature rises to 1500-1600 K, at most 10% of the decomposition of CH2=C=CHCHO produces H + CO + HCCCH2 radicals. Thermodynamic conditions in the reactor have been modeled by computational fluid dynamics and the experimental results are compared to the predictions of three furan pyrolysis mechanisms. Uncertainty in the pressure-dependency of the initiation reaction rates is a possible a source of discrepancy between experimental results and theoretical predictions.
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Affiliation(s)
- Kimberly N Urness
- Center for Combustion and Environmental Research, Department of Mechanical Engineering, University of Colorado at Boulder, Boulder, Colorado 80309-0427, USA
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Hatten CD, Kaskey KR, Warner BJ, Wright EM, McCunn LR. Thermal decomposition products of butyraldehyde. J Chem Phys 2013; 139:214303. [DOI: 10.1063/1.4832898] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Vasiliou AK, Kim JH, Ormond TK, Piech KM, Urness KN, Scheer AM, Robichaud DJ, Mukarakate C, Nimlos MR, Daily JW, Guan Q, Carstensen HH, Ellison GB. Biomass pyrolysis: Thermal decomposition mechanisms of furfural and benzaldehyde. J Chem Phys 2013; 139:104310. [DOI: 10.1063/1.4819788] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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