1
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Changala PB, McCarthy MC. Rotational Spectrum of the Phenoxy Radical. J Phys Chem Lett 2024:5063-5069. [PMID: 38701387 DOI: 10.1021/acs.jpclett.4c00962] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/05/2024]
Abstract
We report the hyperfine-resolved rotational spectrum of the gas-phase phenoxy radical in the 8-25 GHz frequency range using cavity Fourier transform microwave spectroscopy. A complete assignment of its complex but well-resolved fine and hyperfine splittings yielded a precisely determined set of rotational constants, spin-rotation parameters, and nuclear hyperfine coupling constants. These results are interpreted with support from high-level quantum chemical calculations to gain detailed insight into the distribution of the unpaired π electron in this prototypical resonance-stabilized radical. The accurate laboratory rest frequencies enable studies of the chemistry of phenoxy in both the laboratory and space. The prospects of extending the present experimental and theoretical techniques to investigate the rotational spectra of isotopic variants and structural isomers of phenoxy and other important gas-phase radical intermediates that are yet undetected at radio wavelengths are discussed.
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Affiliation(s)
- P Bryan Changala
- Center for Astrophysics | Harvard & Smithsonian Cambridge, Massachusetts 02138, United States
| | - Michael C McCarthy
- Center for Astrophysics | Harvard & Smithsonian Cambridge, Massachusetts 02138, United States
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2
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Fernholz C, Bodi A, Hemberger P. Threshold Photoelectron Spectrum of the Phenoxy Radical. J Phys Chem A 2022; 126:9022-9030. [DOI: 10.1021/acs.jpca.2c06670] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Christin Fernholz
- Laboratory for Synchtrotron Radiation and Femtochemistry, Paul Scherrer Institute, Forschungsstrasse 111, CH-5232Villigen, Switzerland
| | - Andras Bodi
- Laboratory for Synchtrotron Radiation and Femtochemistry, Paul Scherrer Institute, Forschungsstrasse 111, CH-5232Villigen, Switzerland
| | - Patrick Hemberger
- Laboratory for Synchtrotron Radiation and Femtochemistry, Paul Scherrer Institute, Forschungsstrasse 111, CH-5232Villigen, Switzerland
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3
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Puente‐Urbina A, Pan Z, Paunović V, Šot P, Hemberger P, van Bokhoven JA. Direct Evidence on the Mechanism of Methane Conversion under Non-oxidative Conditions over Iron-modified Silica: The Role of Propargyl Radicals Unveiled. Angew Chem Int Ed Engl 2021; 60:24002-24007. [PMID: 34459534 PMCID: PMC8596584 DOI: 10.1002/anie.202107553] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2021] [Indexed: 11/08/2022]
Abstract
Radical-mediated gas-phase reactions play an important role in the conversion of methane under non-oxidative conditions into olefins and aromatics over iron-modified silica catalysts. Herein, we use operando photoelectron photoion coincidence spectroscopy to disentangle the elusive C2+ radical intermediates participating in the complex gas-phase reaction network. Our experiments pinpoint different C2 -C5 radical species that allow for a stepwise growth of the hydrocarbon chains. Propargyl radicals (H2 C-C≡C-H) are identified as essential precursors for the formation of aromatics, which then contribute to the formation of heavier hydrocarbon products via hydrogen abstraction-acetylene addition routes (HACA mechanism). These results provide comprehensive mechanistic insights that are relevant for the development of methane valorization processes.
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Affiliation(s)
- Allen Puente‐Urbina
- Institute for Chemical and BioengineeringDepartment of Chemistry and Applied BiosciencesETH ZurichVladimir-Prelog-Weg 1–5/108093ZurichSwitzerland
| | - Zeyou Pan
- Institute for Chemical and BioengineeringDepartment of Chemistry and Applied BiosciencesETH ZurichVladimir-Prelog-Weg 1–5/108093ZurichSwitzerland
- Laboratory for Synchrotron Radiation and FemtochemistryPaul Scherrer InstituteForschungsstrasse 1115232VilligenSwitzerland
| | - Vladimir Paunović
- Institute for Chemical and BioengineeringDepartment of Chemistry and Applied BiosciencesETH ZurichVladimir-Prelog-Weg 1–5/108093ZurichSwitzerland
| | - Petr Šot
- Institute for Chemical and BioengineeringDepartment of Chemistry and Applied BiosciencesETH ZurichVladimir-Prelog-Weg 1–5/108093ZurichSwitzerland
- Laboratory of Inorganic ChemistryDepartment of Chemistry and Applied BiosciencesETH ZurichVladimir-Prelog-Weg 1–5/108093ZurichSwitzerland
| | - Patrick Hemberger
- Laboratory for Synchrotron Radiation and FemtochemistryPaul Scherrer InstituteForschungsstrasse 1115232VilligenSwitzerland
| | - Jeroen Anton van Bokhoven
- Institute for Chemical and BioengineeringDepartment of Chemistry and Applied BiosciencesETH ZurichVladimir-Prelog-Weg 1–5/108093ZurichSwitzerland
- Laboratory for Catalysis and Sustainable ChemistryPaul Scherrer InstituteForschungsstrasse 1115232VilligenSwitzerland
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4
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Puente‐Urbina A, Pan Z, Paunović V, Šot P, Hemberger P, Bokhoven JA. Direct Evidence on the Mechanism of Methane Conversion under Non‐oxidative Conditions over Iron‐modified Silica: The Role of Propargyl Radicals Unveiled. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202107553] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Allen Puente‐Urbina
- Institute for Chemical and Bioengineering Department of Chemistry and Applied Biosciences ETH Zurich Vladimir-Prelog-Weg 1–5/10 8093 Zurich Switzerland
| | - Zeyou Pan
- Institute for Chemical and Bioengineering Department of Chemistry and Applied Biosciences ETH Zurich Vladimir-Prelog-Weg 1–5/10 8093 Zurich Switzerland
- Laboratory for Synchrotron Radiation and Femtochemistry Paul Scherrer Institute Forschungsstrasse 111 5232 Villigen Switzerland
| | - Vladimir Paunović
- Institute for Chemical and Bioengineering Department of Chemistry and Applied Biosciences ETH Zurich Vladimir-Prelog-Weg 1–5/10 8093 Zurich Switzerland
| | - Petr Šot
- Institute for Chemical and Bioengineering Department of Chemistry and Applied Biosciences ETH Zurich Vladimir-Prelog-Weg 1–5/10 8093 Zurich Switzerland
- Laboratory of Inorganic Chemistry Department of Chemistry and Applied Biosciences ETH Zurich Vladimir-Prelog-Weg 1–5/10 8093 Zurich Switzerland
| | - Patrick Hemberger
- Laboratory for Synchrotron Radiation and Femtochemistry Paul Scherrer Institute Forschungsstrasse 111 5232 Villigen Switzerland
| | - Jeroen Anton Bokhoven
- Institute for Chemical and Bioengineering Department of Chemistry and Applied Biosciences ETH Zurich Vladimir-Prelog-Weg 1–5/10 8093 Zurich Switzerland
- Laboratory for Catalysis and Sustainable Chemistry Paul Scherrer Institute Forschungsstrasse 111 5232 Villigen Switzerland
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5
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Bertini S, Rahaman M, Dutta A, Schollhammer P, Rudnev AV, Gloaguen F, Broekmann P, Albrecht M. Oxo-functionalised mesoionic NHC nickel complexes for selective electrocatalytic reduction of CO 2 to formate. GREEN CHEMISTRY : AN INTERNATIONAL JOURNAL AND GREEN CHEMISTRY RESOURCE : GC 2021; 23:3365-3373. [PMID: 34093085 PMCID: PMC8111538 DOI: 10.1039/d1gc00388g] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Accepted: 04/12/2021] [Indexed: 06/12/2023]
Abstract
Strategies for the conversion of CO2 to valuable products are paramount for reducing the environmental risks associated with high levels of this greenhouse gas and offer unique opportunities for transforming waste into useful products. While catalysts based on nickel as an Earth-abundant metal for the sustainable reduction of CO2 are known, the vast majority produce predominantly CO as a product. Here, efficient and selective CO2 reduction to formate as a synthetically valuable product has been accomplished with novel nickel complexes containing a tailored C,O-bidentate chelating mesoionic carbene ligand. These nickel(ii) complexes are easily accessible and show excellent catalytic activity for electrochemical H+ reduction to H2 (from HOAc in MeCN), and CO2 reduction (from CO2-saturated MeOH/MeCN solution) with high faradaic efficiency to yield formate exclusively as an industrially and synthetically valuable product from CO2. The most active catalyst precursor features the 4,6-di-tert-butyl substituted phenolate triazolylidene ligand, tolerates different proton donors including water, and reaches an unprecedented faradaic efficiency of 83% for formate production, constituting the most active and selective Ni-based system known to date for converting CO2 into formate as an important commodity chemical.
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Affiliation(s)
- Simone Bertini
- Department of Chemistry, Biochemistry &Pharmacy, Universität Bern Freiestrasse 3 3012 Bern Switzerland
| | - Motiar Rahaman
- Department of Chemistry, Biochemistry &Pharmacy, Universität Bern Freiestrasse 3 3012 Bern Switzerland
| | - Abhijit Dutta
- Department of Chemistry, Biochemistry &Pharmacy, Universität Bern Freiestrasse 3 3012 Bern Switzerland
| | | | - Alexander V Rudnev
- Department of Chemistry, Biochemistry &Pharmacy, Universität Bern Freiestrasse 3 3012 Bern Switzerland
- A.N. Frumkin Institute of Physical Chemistry and Electrochemistry Russian Academy of Sciences Leninskii pr. 31 119071 Moscow Russia
| | - Fredric Gloaguen
- UMR 6521, CNRS, Université de Bretagne Occidentale CS 93837 29238 Brest France
| | - Peter Broekmann
- Department of Chemistry, Biochemistry &Pharmacy, Universität Bern Freiestrasse 3 3012 Bern Switzerland
| | - Martin Albrecht
- Department of Chemistry, Biochemistry &Pharmacy, Universität Bern Freiestrasse 3 3012 Bern Switzerland
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6
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Kim Y, Thomas AE, Robichaud DJ, Iisa K, St John PC, Etz BD, Fioroni GM, Dutta A, McCormick RL, Mukarakate C, Kim S. A perspective on biomass-derived biofuels: From catalyst design principles to fuel properties. JOURNAL OF HAZARDOUS MATERIALS 2020; 400:123198. [PMID: 32585513 DOI: 10.1016/j.jhazmat.2020.123198] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Revised: 06/05/2020] [Accepted: 06/09/2020] [Indexed: 05/24/2023]
Abstract
The hazards to health and the environment associated with the transportation sector include smog, particulate matter, and greenhouse gas emissions. Conversion of lignocellulosic biomass into biofuels has the potential to provide significant amounts of infrastructure-compatible liquid transportation fuels that reduce those hazardous materials. However, the development of these technologies is inefficient, due to: (i) the lack of a priori fuel property consideration, (ii) poor shared vocabulary between process chemists and fuel engineers, and (iii) modern and future engines operating outside the range of traditional autoignition metrics such as octane or cetane numbers. In this perspective, we describe an approach where we follow a "fuel-property first" design methodology with a sequence of (i) identifying the desirable fuel properties for modern engines, (ii) defining molecules capable of delivering those properties, and (iii) designing catalysts and processes that can produce those molecules from a candidate feedstock in a specific conversion process. Computational techniques need to be leveraged to minimize expenses and experimental efforts on low-promise options. This concept is illustrated with current research information available for biomass conversion to fuels via catalytic fast pyrolysis and hydrotreating; outstanding challenges and research tools necessary for a successful outcome are presented.
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Affiliation(s)
- Yeonjoon Kim
- National Renewable Energy Laboratory, Golden, CO 80401, United States
| | - Anna E Thomas
- National Renewable Energy Laboratory, Golden, CO 80401, United States
| | - David J Robichaud
- National Renewable Energy Laboratory, Golden, CO 80401, United States
| | - Kristiina Iisa
- National Renewable Energy Laboratory, Golden, CO 80401, United States
| | - Peter C St John
- National Renewable Energy Laboratory, Golden, CO 80401, United States
| | - Brian D Etz
- National Renewable Energy Laboratory, Golden, CO 80401, United States
| | - Gina M Fioroni
- National Renewable Energy Laboratory, Golden, CO 80401, United States
| | - Abhijit Dutta
- National Renewable Energy Laboratory, Golden, CO 80401, United States
| | | | - Calvin Mukarakate
- National Renewable Energy Laboratory, Golden, CO 80401, United States.
| | - Seonah Kim
- National Renewable Energy Laboratory, Golden, CO 80401, United States.
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7
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Wagner JP. An Intramolecular Hydrogen-Shift in a Peroxy Radical at Cryogenic Temperatures: The Reaction of 2-Hydroxyphenyl Radical with O 2. Chemistry 2020; 26:12119-12124. [PMID: 32427391 DOI: 10.1002/chem.202000980] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Indexed: 11/08/2022]
Abstract
Peroxy radical hydrogen-shifts are pivotal elementary reaction steps in the oxidation of small hydrocarbons in autoignition and the lower atmosphere. Although these reactions are typically associated with a substantial barrier, we demonstrate that the [1,5]H-shift in the peroxy species derived from the 2-hydroxyphenyl radical 1 is so facile that it even proceeds rapidly in an argon matrix at 35 K through a proton-coupled electron transfer mechanism. Hydrogen-bound complexes of o-benzoquinone are identified as the main reaction products by infrared spectroscopy although their formation through O-O bond scission is hampered by a barrier of 11.9 kcal mol-1 at the ROCCSD(T)/cc-pVTZ/UB3LYP/6-311G(d,p) level of theory.
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Affiliation(s)
- J Philipp Wagner
- Institut für Organische Chemie, Eberhard Karls Universität Tübingen, Auf der Morgenstelle 18, 72076, Tübingen, Germany
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8
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Pratali Maffei L, Pelucchi M, Faravelli T, Cavallotti C. Theoretical study of sensitive reactions in phenol decomposition. REACT CHEM ENG 2020. [DOI: 10.1039/c9re00418a] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The reactivity of phenol is of utmost importance in combustion systems.
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Affiliation(s)
- Luna Pratali Maffei
- CRECK Modeling Lab
- Department of Chemistry, Materials, and Chemical Engineering
- Politecnico di Milano
- Italy
| | - Matteo Pelucchi
- CRECK Modeling Lab
- Department of Chemistry, Materials, and Chemical Engineering
- Politecnico di Milano
- Italy
| | - Tiziano Faravelli
- CRECK Modeling Lab
- Department of Chemistry, Materials, and Chemical Engineering
- Politecnico di Milano
- Italy
| | - Carlo Cavallotti
- CRECK Modeling Lab
- Department of Chemistry, Materials, and Chemical Engineering
- Politecnico di Milano
- Italy
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9
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Reusch E, Holzmeier F, Gerlach M, Fischer I, Hemberger P. Decomposition of Picolyl Radicals at High Temperature: A Mass Selective Threshold Photoelectron Spectroscopy Study. Chemistry 2019; 25:16652-16659. [PMID: 31637775 PMCID: PMC6972682 DOI: 10.1002/chem.201903937] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Revised: 10/16/2019] [Indexed: 01/24/2023]
Abstract
The reaction products of the picolyl radicals at high temperature were characterized by mass-selective threshold photoelectron spectroscopy in the gas phase. Aminomethylpyridines were pyrolyzed to initially produce picolyl radicals (m/z=92). At higher temperatures further thermal reaction products are generated in the pyrolysis reactor. All compounds were identified by mass-selected threshold photoelectron spectroscopy and several hitherto unexplored reactive molecules were characterized. The mechanism for several dissociation pathways was outlined in computations. The spectrum of m/z=91, resulting from hydrogen loss of picolyl, shows four isomers, two ethynyl pyrroles with adiabatic ionization energies (IEad ) of 7.99 eV (2-ethynyl-1H-pyrrole) and 8.12 eV (3-ethynyl-1H-pyrrole), and two cyclopentadiene carbonitriles with IE's of 9.14 eV (cyclopenta-1,3-diene-1-carbonitrile) and 9.25 eV (cyclopenta-1,4-diene-1-carbonitrile). A second consecutive hydrogen loss forms the cyanocyclopentadienyl radical with IE's of 9.07 eV (T0 ) and 9.21 eV (S1 ). This compound dissociates further to acetylene and the cyanopropynyl radical (IE=9.35 eV). Furthermore, the cyclopentadienyl radical, penta-1,3-diyne, cyclopentadiene and propargyl were identified in the spectra. Computations indicate that dissociation of picolyl proceeds initially via a resonance-stabilized seven-membered ring.
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Affiliation(s)
- Engelbert Reusch
- Institute of Physical and Theoretical ChemistryUniversity of WürzburgAm Hubland Süd97074WürzburgGermany
| | - Fabian Holzmeier
- Dipartimento di FisicaPolitecnico di MilanoPiazza Leonardo da Vinci 3220133MilanoItaly
| | - Marius Gerlach
- Institute of Physical and Theoretical ChemistryUniversity of WürzburgAm Hubland Süd97074WürzburgGermany
| | - Ingo Fischer
- Institute of Physical and Theoretical ChemistryUniversity of WürzburgAm Hubland Süd97074WürzburgGermany
| | - Patrick Hemberger
- Laboratory for Femtochemistry and Synchrotron RadiationPaul Scherrer Institut (PSI)5232VilligenSwitzerland
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10
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Roohi H, Moghadam B. Decomposition mechanism of the phenylaminyl C6H5N H radical to propargyl and acetylene: A M06-2X, CBS-QB3 and G4 study. Chem Phys Lett 2019. [DOI: 10.1016/j.cplett.2019.06.018] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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11
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Sullivan EN, Nichols B, Neumark DM. Fast beam photofragment translational spectroscopy of the phenoxy radical at 225 nm, 290 nm, and 533 nm. Phys Chem Chem Phys 2019; 21:14270-14277. [PMID: 30566134 DOI: 10.1039/c8cp06818f] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Photodissociation of the phenoxy radical (C6H5O) is investigated using fast beam photofragment translational spectroscopy. Phenoxy radicals are generated through photodetachment of phenoxide anions (C6H5O-) at 532 nm. Following photoexcitation of the radicals at 225 nm (5.51 eV), 290 nm (4.27 eV), or 533 nm (2.33 eV), photofragments are collected in coincidence to determine their masses, translational energy, and scattering angle for each dissociation event. Two-body dissociation yields exclusively CO + C5H5, and three-body dissociation to CO + C2H2 + C3H3 and CO + C5H4 + H is also seen at the two higher energies. The translational energy distributions for two-body dissociation suggest that dissociation occurs via internal conversion to the ground electronic state followed by statistical dissociation. The absorption of an additional 532 nm photon in the photodetachment region provides some C6H5O radicals with an additional 2.33 eV of energy, leading to much of the two-body dissociation observed at 533 nm and the three-body dissociation at the two higher excitation energies.
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Affiliation(s)
- Erin N Sullivan
- Department of Chemistry, University of California, Berkeley, California 94720, USA.
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12
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Wu XK, Tang XF, Zhou XG, Liu SL. Dissociation dynamics of energy-selected ions using threshold photoelectron-photoion coincidence velocity imaging. CHINESE J CHEM PHYS 2019. [DOI: 10.1063/1674-0068/cjcp1811257] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Affiliation(s)
- Xiang-kun Wu
- Hefei National Laboratory for Physical Sciences at the Microscale, iChEM (Collaborative Innovation Center of Chemistry for Energy Materials), Department of Chemical Physics, University of Science and Technology of China, Hefei 230026, China
| | - Xiao-feng Tang
- Laboratory of Atmospheric Physico-Chemistry, Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Hefei 230031, China
| | - Xiao-guo Zhou
- Hefei National Laboratory for Physical Sciences at the Microscale, iChEM (Collaborative Innovation Center of Chemistry for Energy Materials), Department of Chemical Physics, University of Science and Technology of China, Hefei 230026, China
| | - Shi-lin Liu
- Hefei National Laboratory for Physical Sciences at the Microscale, iChEM (Collaborative Innovation Center of Chemistry for Energy Materials), Department of Chemical Physics, University of Science and Technology of China, Hefei 230026, China
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13
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Gerlach M, Bodi A, Hemberger P. Metamorphic meta isomer: carbon dioxide and ketenes are formed via retro-Diels–Alder reactions in the decomposition of meta-benzenediol. Phys Chem Chem Phys 2019; 21:19480-19487. [DOI: 10.1039/c9cp03519b] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Deoxygenation of the lignin model compound resorcinol was investigated using VUV synchrotron radiation: Formation of two reactive ketenes and decarboxylation are the dominating pathways, much different from the other two benzenediol isomers.
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Affiliation(s)
- Marius Gerlach
- Laboratory for Synchrotron Radiation and Femtochemistry
- Paul Scherrer Institute
- CH-5234 Villigen PSI
- Switzerland
| | - Andras Bodi
- Laboratory for Synchrotron Radiation and Femtochemistry
- Paul Scherrer Institute
- CH-5234 Villigen PSI
- Switzerland
| | - Patrick Hemberger
- Laboratory for Synchrotron Radiation and Femtochemistry
- Paul Scherrer Institute
- CH-5234 Villigen PSI
- Switzerland
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14
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Kroflič A, Huš M, Grilc M, Grgić I. Underappreciated and Complex Role of Nitrous Acid in Aromatic Nitration under Mild Environmental Conditions: The Case of Activated Methoxyphenols. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2018; 52:13756-13765. [PMID: 30388370 DOI: 10.1021/acs.est.8b01903] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Many ambiguities surround the possible mechanisms of colored and toxic nitrophenols formation in natural systems. Nitration of a biologically and environmentally relevant aromatic compound, guaiacol (2-methoxyphenol), under mild aqueous-phase conditions (ambient temperatures, pH 4.5) was investigated by a temperature-dependent experimental modeling coupled to extensive ab initio calculations to obtain the activation energies of the modeled reaction pathways. The importance of dark nonradical reactions is emphasized, involving nitrous (HNO2) and peroxynitrous (HOONO) acids. Oxidation by HOONO is shown to proceed via a nonradical pathway, possibly involving the nitronium ion (NO2+) formation. Using quantum chemical calculations at the MP2/6-31++g(d,p) level, NO2• is shown capable of abstracting a hydrogen atom from the phenolic group on the aromatic ring. In a protic solvent, the corresponding aryl radical can combine with HNO2 to yield OH• and, after a subsequent oxidation step, nitrated aromatic products. The demonstrated chemistry is especially important for understanding the aging of nighttime atmospheric deliquesced aerosol. The relevance should be further investigated in the atmospheric gaseous phase. The results of this study have direct implications for accurate modeling of the burden of toxic nitroaromatic pollutants, and the formation of atmospheric brown carbon and its associated influence on Earth's albedo and climate forcing.
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Affiliation(s)
- Ana Kroflič
- Department of Analytical Chemistry , National Institute of Chemistry , Hajdrihova 19 , SI-1000 Ljubljana , Slovenia
| | - Matej Huš
- Department of Physics , Chalmers University of Technology , Fysikgränd 3 , SE-412 96 Gothenburg , Sweden
- Department of Catalysis and Chemical Reaction Engineering , National Institute of Chemistry , Hajdrihova 19 , SI-1000 Ljubljana , Slovenia
| | - Miha Grilc
- Department of Catalysis and Chemical Reaction Engineering , National Institute of Chemistry , Hajdrihova 19 , SI-1000 Ljubljana , Slovenia
- Institute of Chemical Technology , Leipzig University , Linnéstraße 3 , DE-04103 Leipzig , Germany
| | - Irena Grgić
- Department of Analytical Chemistry , National Institute of Chemistry , Hajdrihova 19 , SI-1000 Ljubljana , Slovenia
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15
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Zhu GZ, Qian CH, Wang LS. Dipole-bound excited states and resonant photoelectron imaging of phenoxide and thiophenoxide anions. J Chem Phys 2018; 149:164301. [DOI: 10.1063/1.5049715] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Affiliation(s)
- Guo-Zhu Zhu
- Department of Chemistry, Brown University, Providence, Rhode Island 02912, USA
| | - Chen-Hui Qian
- Department of Chemistry, Brown University, Providence, Rhode Island 02912, USA
| | - Lai-Sheng Wang
- Department of Chemistry, Brown University, Providence, Rhode Island 02912, USA
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16
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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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17
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Understanding the mechanism of catalytic fast pyrolysis by unveiling reactive intermediates in heterogeneous catalysis. Nat Commun 2017; 8:15946. [PMID: 28660882 PMCID: PMC5493764 DOI: 10.1038/ncomms15946] [Citation(s) in RCA: 88] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Accepted: 05/08/2017] [Indexed: 12/27/2022] Open
Abstract
Catalytic fast pyrolysis is a promising way to convert lignin into fine chemicals and fuels, but current approaches lack selectivity and yield unsatisfactory conversion. Understanding the pyrolysis reaction mechanism at the molecular level may help to make this sustainable process more economic. Reactive intermediates are responsible for product branching and hold the key to unveiling these mechanisms, but are notoriously difficult to detect isomer-selectively. Here, we investigate the catalytic pyrolysis of guaiacol, a lignin model compound, using photoelectron photoion coincidence spectroscopy with synchrotron radiation, which allows for isomer-selective detection of reactive intermediates. In combination with ambient pressure pyrolysis, we identify fulvenone as the central reactive intermediate, generated by catalytic demethylation to catechol and subsequent dehydration. The fulvenone ketene is responsible for the phenol formation. This technique may open unique opportunities for isomer-resolved probing in catalysis, and holds the potential for achieving a mechanistic understanding of complex, real-life catalytic processes. The conversion of lignin by catalytic fast pyrolysis into useful fine chemicals is a promising route to fuel production, however selectivity and conversion are still not optimal. Here, the authors investigate the reaction mechanism by detection of reactive intermediates responsible for the formation of key products.
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Custodis VBF, Hemberger P, van Bokhoven JA. How Inter- and Intramolecular Reactions Dominate the Formation of Products in Lignin Pyrolysis. Chemistry 2017; 23:8658-8668. [DOI: 10.1002/chem.201700639] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2017] [Indexed: 11/10/2022]
Affiliation(s)
- Victoria B. F. Custodis
- Institute for Chemical and Bioengineering; Department of Chemistry and Applied Biosciences; 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
| | - Patrick Hemberger
- Laboratory for Femtochemistry and Synchrotron Radiation; Paul Scherrer Institute; CH-5232 Villigen-PSI Switzerland
| | - Jeroen A. van Bokhoven
- Institute for Chemical and Bioengineering; Department of Chemistry and Applied Biosciences; 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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Asatryan R, Bennadji H, Bozzelli JW, Ruckenstein E, Khachatryan L. Molecular Products and Fundamentally Based Reaction Pathways in the Gas-Phase Pyrolysis of the Lignin Model Compound p-Coumaryl Alcohol. J Phys Chem A 2017; 121:3352-3371. [PMID: 28406634 DOI: 10.1021/acs.jpca.7b01656] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The fractional pyrolysis of lignin model compound para-coumaryl alcohol (p-CMA) containing a propanoid side chain and a phenolic OH group was studied using the System for Thermal Diagnostic Studies at temperatures from 200 to 900 °C, in order to gain mechanistic insight into the role of large substituents in high-lignin feedstocks pyrolysis. Phenol and its simple derivatives p-cresol, ethyl-, propenyl-, and propyl-phenols were found to be the major products predominantly formed at low pyrolysis temperatures (<500 °C). A cryogenic trapping technique was employed combined with EPR spectroscopy to identify the open-shell intermediates registered at pyrolysis temperatures above 500 °C. These were characterized as radical mixtures primarily consisting of oxygen-linked conjugated radicals. A comprehensive potential energy surface analysis of p-CMA and p-CMA + H atom systems was performed using various DFT protocols to examine the possible role of concerted molecular eliminations and free-radical mechanisms in the formation of major products. Other significant unimolecular concerted reactions along with formation and decomposition of primary radicals are also described and evaluated. The calculations suggest that a set of the chemically activated secondary radical channels is relevant to the low temperature product formation under fractional pyrolysis conditions.
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Affiliation(s)
- Rubik Asatryan
- Department of Chemical and Biological Engineering, University at Buffalo, The State University of New York , Buffalo, New York 14226, United States
| | - Hayat Bennadji
- Department of Environmental Sciences, Louisiana State University , Baton Rouge, Louisiana 70808, United States
| | - Joseph W Bozzelli
- Department of Chemistry and Environmental Science, New Jersey Institute of Technology , Newark, New Jersey 07102, United States
| | - Eli Ruckenstein
- Department of Chemical and Biological Engineering, University at Buffalo, The State University of New York , Buffalo, New York 14226, United States
| | - Lavrent Khachatryan
- Department of Chemistry, Louisiana State University , Baton Rouge, Louisiana 70803, United States
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Liang S, Hemberger P, Levalois‐Grützmacher J, Grützmacher H, Gaan S. Probing Phosphorus Nitride (P≡N) and Other Elusive Species Formed upon Pyrolysis of Dimethyl Phosphoramidate. Chemistry 2017; 23:5595-5601. [DOI: 10.1002/chem.201700402] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2017] [Indexed: 11/05/2022]
Affiliation(s)
- Shuyu Liang
- Laboratory of Inorganic Chemistry ETH Zürich, Swiss Federal Institute of Technology Vladimir-Prelog-Weg 1-5/10 8093 Zürich Switzerland
- Additives and Chemistry, Advanced Fibers Empa, Swiss Federal Laboratories for Materials Science Lerchenfeldstrasse 5 9014 St. Gallen Switzerland
| | - Patrick Hemberger
- Laboratory for Femtochemistry and Synchrotron Radiation Paul Scherrer Institute WSLA/115 5232 Villigen-PSI Switzerland
| | - Joëlle Levalois‐Grützmacher
- Laboratory of Inorganic Chemistry ETH Zürich, Swiss Federal Institute of Technology Vladimir-Prelog-Weg 1-5/10 8093 Zürich Switzerland
| | - Hansjörg Grützmacher
- Laboratory of Inorganic Chemistry ETH Zürich, Swiss Federal Institute of Technology Vladimir-Prelog-Weg 1-5/10 8093 Zürich Switzerland
| | - Sabyasachi Gaan
- Additives and Chemistry, Advanced Fibers Empa, Swiss Federal Laboratories for Materials Science Lerchenfeldstrasse 5 9014 St. Gallen Switzerland
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Kotha RR, Nash JJ, Kenttämaa HI. An Oxygen‐
peri
‐Bridged Quinolinium Cation and Its Monoradical Counterpart. European J Org Chem 2017. [DOI: 10.1002/ejoc.201601572] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Raghavendhar R. Kotha
- Department of Chemistry Purdue University 560 Oval Drive 47907‐2084 West Lafayette IN USA
| | - John J. Nash
- Department of Chemistry Purdue University 560 Oval Drive 47907‐2084 West Lafayette IN USA
| | - Hilkka I. Kenttämaa
- Department of Chemistry Purdue University 560 Oval Drive 47907‐2084 West Lafayette IN USA
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22
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da Silva G. Mystery of 1-Vinylpropargyl Formation from Acetylene Addition to the Propargyl Radical: An Open-and-Shut Case. J Phys Chem A 2017; 121:2086-2095. [DOI: 10.1021/acs.jpca.6b12996] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Gabriel da Silva
- Department of Chemical and
Biomolecular Engineering, The University of Melbourne, Melbourne, Victoria 3010, Australia
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23
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Heringa MF, Slowik JG, Prévôt ASH, Baltensperger U, Hemberger P, Bodi A. Dissociative Ionization Mechanism and Appearance Energies in Adipic Acid Revealed by Imaging Photoelectron Photoion Coincidence, Selective Deuteration, and Calculations. J Phys Chem A 2016; 120:3397-405. [DOI: 10.1021/acs.jpca.6b00908] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Maarten F. Heringa
- Laboratory
of Atmospheric Chemistry, Paul Scherrer Institute, Villigen PSI, Switzerland
- Laboratory
for Synchrotron Radiation and Femtochemistry, Paul Scherrer Institute, Villigen
PSI, Switzerland
| | - Jay G. Slowik
- Laboratory
of Atmospheric Chemistry, Paul Scherrer Institute, Villigen PSI, Switzerland
| | - André S. H. Prévôt
- Laboratory
of Atmospheric Chemistry, Paul Scherrer Institute, Villigen PSI, Switzerland
| | - Urs Baltensperger
- Laboratory
of Atmospheric Chemistry, Paul Scherrer Institute, Villigen PSI, Switzerland
| | - Patrick Hemberger
- Laboratory
for Synchrotron Radiation and Femtochemistry, Paul Scherrer Institute, Villigen
PSI, Switzerland
| | - Andras Bodi
- Laboratory
for Synchrotron Radiation and Femtochemistry, Paul Scherrer Institute, Villigen
PSI, Switzerland
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24
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Holzmeier F, Wagner I, Fischer I, Bodi A, Hemberger P. Pyrolysis of 3-Methoxypyridine. Detection and Characterization of the Pyrrolyl Radical by Threshold Photoelectron Spectroscopy. J Phys Chem A 2016; 120:4702-10. [DOI: 10.1021/acs.jpca.5b10743] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Fabian Holzmeier
- Institute
of Physical and Theoretical Chemistry, University of Würzburg, Am Hubland D-97074, Germany
| | - Isabella Wagner
- Institute
of Physical and Theoretical Chemistry, University of Würzburg, Am Hubland D-97074, Germany
| | - Ingo Fischer
- Institute
of Physical and Theoretical Chemistry, University of Würzburg, Am Hubland D-97074, Germany
| | - Andras Bodi
- Molecular
Dynamics Group, Paul Scherrer Institut, CH-5232 Villigen
PSI, Switzerland
| | - Patrick Hemberger
- Molecular
Dynamics Group, Paul Scherrer Institut, CH-5232 Villigen
PSI, Switzerland
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