1
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Azizova LR, Kulik TV, Palianytsia BB, Ilchenko MM, Telbiz GM, Balu AM, Tarnavskiy S, Luque R, Roldan A, Kartel MT. The Role of Surface Complexes in Ketene Formation from Fatty Acids via Pyrolysis over Silica: from Platform Molecules to Waste Biomass. J Am Chem Soc 2023; 145:26592-26610. [PMID: 38047620 PMCID: PMC10722514 DOI: 10.1021/jacs.3c06966] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2023] [Revised: 11/02/2023] [Accepted: 11/06/2023] [Indexed: 12/05/2023]
Abstract
Fatty acids (FA) are the main constituents of lipids and oil crop waste, considered to be a promising 2G biomass that can be converted into ketenes via catalytic pyrolysis. Ketenes are appraised as promising synthons for the pharmaceutical, polymer, and chemical industries. Progress in the thermal conversion of short- and long-chain fatty acids into ketenes requires a deep understanding of their interaction mechanisms with the nanoscale oxide catalysts. In this work, the interactions of fatty acids with silica are investigated using a wide range of experimental and computational techniques (TPD MS, DFT, FTIR, in situ IR, equilibrium adsorption, and thermogravimetry). The adsorption isotherms of linear and branched fatty acids C1-C6 on the silica surface from aqueous solution have been obtained. The relative quantities of different types of surface complexes, as well as kinetic parameters of their decomposition, were calculated. The formation of surface complexes with a coordination bond between the carbonyl oxygens and silicon atoms in the surface-active center, which becomes pentacoordinate, was confirmed by DFT calculations, in good agreement with the IR feature at ∼1680 cm 1. Interestingly, ketenes release relate to these complexes' decomposition as confirmed by the thermal evolution of the absorption band (1680 cm-1) synchronously with the TPD peak of the ketene molecular ion. The established regularities of the ketenezation are also observed for the silica-induced pyrolysis of glyceryl trimyristate and real waste, rapeseed meals.
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Affiliation(s)
- Liana R. Azizova
- School
of Dentistry, Cardiff University, Heath Park, Cardiff CF14 4XY, U.K.
- Chuiko
Institute of Surface Chemistry, National
Academy of Science of Ukraine, Kyiv 03164, Ukraine
| | - Tetiana V. Kulik
- Chuiko
Institute of Surface Chemistry, National
Academy of Science of Ukraine, Kyiv 03164, Ukraine
- Cardiff
Catalysis Institute, School of Chemistry, Cardiff University, Main Building, Park Place, Cardiff CF10 3AT, U.K.
| | - Borys B. Palianytsia
- Chuiko
Institute of Surface Chemistry, National
Academy of Science of Ukraine, Kyiv 03164, Ukraine
- Departamento
de Química Orgánica, Universidad
de Córdoba, Campus de Rabanales, Edificio Marie Curie (C-3), Ctra Nnal IV-A,
Km 396, Cordoba E14014, Spain
| | - Mykola M. Ilchenko
- Institute
of Molecular Biology and Genetics, National Academy of Science of
Ukraine, 150 Zabolotnogo Str., Kyiv 03680, Ukraine
| | - German M. Telbiz
- National
Academy of Science of Ukraine, L. V. Pisarzhevsky
Institute of Physical Chemistry, Nauky Av. 31, Kyiv 03039, Ukraine
| | - Alina M. Balu
- Departamento
de Química Orgánica, Universidad
de Córdoba, Campus de Rabanales, Edificio Marie Curie (C-3), Ctra Nnal IV-A,
Km 396, Cordoba E14014, Spain
| | - Sergiy Tarnavskiy
- Institute
of Molecular Biology and Genetics, National Academy of Science of
Ukraine, 150 Zabolotnogo Str., Kyiv 03680, Ukraine
| | - Rafael Luque
- Universitá
degli studi Mediterranea di Reggio Calabria (UNIRC), DICEAM, Via Zehender
(giá via Graziella), Loc. Feo di Vito, I89122 Reggio Calabria, Italy
- Universidad
ECOTEC, Km. 13.5 Samborondón, Samborondón EC092302, Ecuador
| | - Alberto Roldan
- Cardiff
Catalysis Institute, School of Chemistry, Cardiff University, Main Building, Park Place, Cardiff CF10 3AT, U.K.
| | - Mykola T. Kartel
- Chuiko
Institute of Surface Chemistry, National
Academy of Science of Ukraine, Kyiv 03164, Ukraine
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2
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Hemberger P, Pan Z, Wu X, Zhang Z, Kanayama K, Bodi A. Photoion Mass-Selected Threshold Photoelectron Spectroscopy to Detect Reactive Intermediates in Catalysis: From Instrumentation and Examples to Peculiarities and a Database. THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2023; 127:16751-16763. [PMID: 37670794 PMCID: PMC10476201 DOI: 10.1021/acs.jpcc.3c03120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2023] [Revised: 08/04/2023] [Indexed: 09/07/2023]
Abstract
Photoion mass-selected threshold photoelectron spectroscopy (ms-TPES) is a synchrotron-based, universal, sensitive, and multiplexed detection tool applied in the areas of catalysis, combustion, and gas-phase reactions. Isomer-selective vibrational fingerprints in the ms-TPES of stable and reactive intermediates allow for unequivocal assignment of spectral carriers. Case studies are presented on heterogeneous catalysis, revealing the role of ketenes in the methanol-to-olefins process, the catalytic pyrolysis mechanism of lignin model compounds, and the radical chemistry upon C-H activation in oxyhalogenation. These studies demonstrate the potential of ms-TPES as an analytical technique for elucidating complex reaction mechanisms. We examine the robustness of ms-TPES assignments and address sampling effects, especially the temperature dependence of ms-TPES due to rovibrational broadening. Data acquisition approaches and the Stark shift from the extraction field are also considered to arrive at general recommendations. Finally, the PhotoElectron PhotoIon Spectral Compendium (https://pepisco.psi.ch), a spectral database hosted at Paul Scherrer Institute to support assignment, is introduced.
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Affiliation(s)
| | - Zeyou Pan
- Paul
Scherrer Institute, Villigen 5232, Switzerland
| | - Xiangkun Wu
- Paul
Scherrer Institute, Villigen 5232, Switzerland
| | - Zihao Zhang
- Paul
Scherrer Institute, Villigen 5232, Switzerland
| | - Keisuke Kanayama
- Paul
Scherrer Institute, Villigen 5232, Switzerland
- Institute
of Fluid Science, Tohoku University 2-1-1 Katahira, Aoba, Sendai 980-8577, Miyagi, Japan
- Graduate
School of Engineering, Tohoku University, 6-6 Aramaki Aza Aoba, Aoba, Sendai 980-8579, Miyagi, Japan
| | - Andras Bodi
- Paul
Scherrer Institute, Villigen 5232, Switzerland
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3
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Pan Z, Puente-Urbina A, Batool SR, Bodi A, Wu X, Zhang Z, van Bokhoven JA, Hemberger P. Tuning the zeolite acidity enables selectivity control by suppressing ketene formation in lignin catalytic pyrolysis. Nat Commun 2023; 14:4512. [PMID: 37500623 PMCID: PMC10374901 DOI: 10.1038/s41467-023-40179-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Accepted: 07/12/2023] [Indexed: 07/29/2023] Open
Abstract
Unveiling catalytic mechanisms at a molecular level aids rational catalyst design and selectivity control for process optimization. In this study, we find that the Brønsted acid site density of the zeolite catalyst efficiently controls the guaiacol catalytic pyrolysis mechanism. Guaiacol demethylation to catechol initiates the reaction, as evidenced by the detected methyl radicals. The mechanism branches to form either fulvenone (c-C5H4 = C = O), a reactive ketene intermediate, by catechol dehydration, or phenol by acid-catalyzed dehydroxylation. At high Brønsted acid site density, fulvenone formation is inhibited due to surface coordination configuration of its precursor, catechol. By quantifying reactive intermediates and products utilizing operando photoelectron photoion coincidence spectroscopy, we find evidence that ketene suppression is responsible for the fivefold phenol selectivity increase. Complementary fulvenone reaction pathway calculations, along with 29Si NMR-MAS spectroscopy results corroborate the mechanism. The proposed, flexible operando approach is applicable to a broad variety of heterogeneous catalytic reactions.
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Affiliation(s)
- Zeyou Pan
- Paul Scherrer Institute, Forschungsstrasse 111, CH-5232, Villigen PSI, Switzerland
- Institute for Chemical and Bioengineering, Department of Chemistry and Applied Biosciences, ETH Zurich, 8093, Zurich, Switzerland
| | - Allen Puente-Urbina
- Institute for Chemical and Bioengineering, Department of Chemistry and Applied Biosciences, ETH Zurich, 8093, Zurich, Switzerland
- Renewable Resources and Enabling Sciences Center, National Renewable Energy Laboratory, Golden, CO, 80401, USA
| | - Syeda Rabia Batool
- Institute for Chemical and Bioengineering, Department of Chemistry and Applied Biosciences, ETH Zurich, 8093, Zurich, Switzerland
| | - Andras Bodi
- Paul Scherrer Institute, Forschungsstrasse 111, CH-5232, Villigen PSI, Switzerland
| | - Xiangkun Wu
- Paul Scherrer Institute, Forschungsstrasse 111, CH-5232, Villigen PSI, Switzerland
| | - Zihao Zhang
- Paul Scherrer Institute, Forschungsstrasse 111, CH-5232, Villigen PSI, Switzerland
| | - Jeroen A van Bokhoven
- Paul Scherrer Institute, Forschungsstrasse 111, CH-5232, Villigen PSI, Switzerland.
- Institute for Chemical and Bioengineering, Department of Chemistry and Applied Biosciences, ETH Zurich, 8093, Zurich, Switzerland.
| | - Patrick Hemberger
- Paul Scherrer Institute, Forschungsstrasse 111, CH-5232, Villigen PSI, Switzerland.
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4
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Pan Z, Bodi A, van Bokhoven JA, Hemberger P. Operando PEPICO unveils the catalytic fast pyrolysis mechanism of the three methoxyphenol isomers. Phys Chem Chem Phys 2022; 24:21786-21793. [PMID: 36082786 PMCID: PMC9491049 DOI: 10.1039/d2cp02741k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The development of lignin valorization processes such as catalytic fast pyrolysis (CFP) to produce fine chemicals and fuels leads to a more sustainable future. The implementation of CFP is enabled by understanding the chemistry of lignin constituents, which, however, requires thorough mechanistic investigations by detecting reactive species. In this contribution, we investigate the CFP of the three methoxyphenol (MP) isomers over H-ZSM-5 utilizing vacuum ultraviolet synchrotron radiation and operando photoelectron photoion coincidence (PEPICO) spectroscopy. All isomers demethylate at first to yield benzenediols, from which dehydroxylation reactions proceed to produce phenol and benzene. Additional pathways to form benzene proceed over cyclopentadiene, methylcyclopentadiene, and fulvene intermediates. The detection of trace amounts of methanol in the product stream suggests a demethoxylation reaction to yield phenol. Guaiacol (2- or ortho-MP) exhibits slightly higher reactivity compared to 3-MP and 4-MP, due to the formation of the fulvenone ketene, which opens additional routes to benzene and phenol. When compared to benzenediol catalytic pyrolysis, the additional methyl group in MP leads to high conversion at lower reactor temperatures, which is mostly owed to the lower H3C–O vs. H–O bond energy and the possibility to demethoxylate to produce phenol. Demethylation, demethoxylation and fulvenone ketene formation determine the reactivity of methoxyphenols over H-ZSM-5 to yield phenols, benzene and toluene. Intermediates are isomer-selectively detected utilizing threshold photoelectron spectroscopy.![]()
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Affiliation(s)
- Zeyou Pan
- Paul Scherrer Institute, 5232 Villigen, Switzerland. .,Institute for Chemical and Bioengineering, Department of Chemistry and Applied Biosciences, ETH Zurich, 8093 Zurich, Switzerland
| | - Andras Bodi
- Paul Scherrer Institute, 5232 Villigen, Switzerland.
| | - Jeroen A van Bokhoven
- Paul Scherrer Institute, 5232 Villigen, Switzerland. .,Institute for Chemical and Bioengineering, Department of Chemistry and Applied Biosciences, ETH Zurich, 8093 Zurich, Switzerland
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5
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Gong X, Çağlayan M, Ye Y, Liu K, Gascon J, Dutta Chowdhury A. First-Generation Organic Reaction Intermediates in Zeolite Chemistry and Catalysis. Chem Rev 2022; 122:14275-14345. [PMID: 35947790 DOI: 10.1021/acs.chemrev.2c00076] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Zeolite chemistry and catalysis are expected to play a decisive role in the next decade(s) to build a more decentralized renewable feedstock-dependent sustainable society owing to the increased scrutiny over carbon emissions. Therefore, the lack of fundamental and mechanistic understanding of these processes is a critical "technical bottleneck" that must be eliminated to maximize economic value and minimize waste. We have identified, considering this objective, that the chemistry related to the first-generation reaction intermediates (i.e., carbocations, radicals, carbenes, ketenes, and carbanions) in zeolite chemistry and catalysis is highly underdeveloped or undervalued compared to other catalysis streams (e.g., homogeneous catalysis). This limitation can often be attributed to the technological restrictions to detect such "short-lived and highly reactive" intermediates at the interface (gas-solid/solid-liquid); however, the recent rise of sophisticated spectroscopic/analytical techniques (including under in situ/operando conditions) and modern data analysis methods collectively compete to unravel the impact of these organic intermediates. This comprehensive review summarizes the state-of-the-art first-generation organic reaction intermediates in zeolite chemistry and catalysis and evaluates their existing challenges and future prospects, to contribute significantly to the "circular carbon economy" initiatives.
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Affiliation(s)
- Xuan Gong
- College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072, Hubei P. R. China
| | - Mustafa Çağlayan
- KAUST Catalysis Center (KCC), King Abdullah University of Science and Technology (KAUST), Thuwal 23955, Saudi Arabia
| | - Yiru Ye
- College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072, Hubei P. R. China
| | - Kun Liu
- College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072, Hubei P. R. China
| | - Jorge Gascon
- KAUST Catalysis Center (KCC), King Abdullah University of Science and Technology (KAUST), Thuwal 23955, Saudi Arabia
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6
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Hemberger P, Wu X, Pan Z, Bodi A. Continuous Pyrolysis Microreactors: Hot Sources with Little Cooling? New Insights Utilizing Cation Velocity Map Imaging and Threshold Photoelectron Spectroscopy. J Phys Chem A 2022; 126:2196-2210. [PMID: 35316066 DOI: 10.1021/acs.jpca.2c00766] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Resistively heated silicon carbide microreactors are widely applied as continuous sources to selectively prepare elusive and reactive intermediates with astrochemical, catalytic, or combustion relevance to measure their photoelectron spectrum. These reactors also provide deep mechanistic insights into uni- and bimolecular chemistry. However, the sampling conditions and effects have not been fully characterized. We use cation velocity map imaging to measure the velocity distribution of the molecular beam signal and to quantify the scattered, rethermalized background sample. Although translational cooling is efficient in the adiabatic expansion from the reactor, the breakdown diagrams of methane and chlorobenzene confirm that the molecular beam component exhibits a rovibrational temperature comparable with that of the reactor. Thus, rovibrational cooling is practically absent in the expansion from the microreactor. The high rovibrational temperature also affects the threshold photoelectron spectrum of both benzene and the allyl radical in the molecular beam, but to different degrees. While the extreme broadening of the benzene TPES suggests a complex ionization mechanism, the allyl TPES is in fact consistent with an internal temperature close to that of the reactor. The background, room-temperature spectra of both are superbly reproduced by Franck-Condon simulations at 300 K. On the one hand, this leads us to suggest that room-temperature reference spectra should be used in species identification. On the other hand, analysis of the allyl iodide pyrolysis data shows that iodine atoms often recombine to form molecular iodine on the chamber surfaces. Such sampling effects may distort the chemical composition of the scattered background with respect to the molecular beam signal emanating directly from the reactor. This must be considered in quantitative analyses and kinetic modeling.
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Affiliation(s)
- Patrick Hemberger
- Paul Scherrer Insitute, Forschungsstrasse 111, CH-5232 Villigen PSI, Switzerland
| | - Xiangkun Wu
- Paul Scherrer Insitute, Forschungsstrasse 111, CH-5232 Villigen PSI, Switzerland
| | - Zeyou Pan
- Paul Scherrer Insitute, Forschungsstrasse 111, CH-5232 Villigen PSI, Switzerland
| | - Andras Bodi
- Paul Scherrer Insitute, Forschungsstrasse 111, CH-5232 Villigen PSI, Switzerland
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7
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Pan Z, Bodi A, van Bokhoven JA, Hemberger P. On the absolute photoionization cross section and threshold photoelectron spectrum of two reactive ketenes in lignin valorization: fulvenone and 2-carbonyl cyclohexadienone. Phys Chem Chem Phys 2022; 24:3655-3663. [PMID: 35080222 PMCID: PMC8827046 DOI: 10.1039/d1cp05206c] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
We report the absolute photoionization cross section (PICS) of fulvenone and 2-carbonyl cyclohexadienone, two crucial ketene intermediates in lignin pyrolysis, combustion and organic synthesis. Both species were generated in situ by pyrolyzing salicylamide and dectected via imaging photoelectron photoion coincidence spectroscopy. In a deamination reaction, salicylamide loses ammonia yielding 2-carbonyl cyclohexadienone, a ketoketene, which further decarbonylates at higher pyrolysis temperatures to form fulvenone. We recorded the threshold photoelectron spectrum of the ketoketene and assigned the ground state (X̃+2A′′ ← X̃1A′) and excited state (Ã+2A′ ← X̃1A′) bands with the help of Franck–Condon simulations. Adiabatic ionization energies are 8.35 ± 0.01 and 9.19 ± 0.01 eV. In a minor reaction channel, the ketoketene isomerizes to benzpropiolactone, which decomposes subsequently to benzyne by CO2 loss. Potential energy surface and RRKM rate constant calculations agree with our experimental observations that the decarbonylation to fulvenone outcompetes the decarboxylation to benzyne by almost two orders of magnitude. The absolute PICS of fulvenone at 10.48 eV was determined to be 18.8 ± 3.8 Mb using NH3 as a calibrant. The PICS of 2-carbonyl cyclohexadienone was found to be 21.5 ± 8.6 Mb at 9 eV. Our PICS measument will enable the quantification of reactive ketenes in lignin valorization and combustion processes using photoionization techniques and provide advanced mechanistic and kinetics insights to aid the bottom-up optimization of such processes. The absolute photoionization cross section (PICS) of these crucial ketene intermediates supports their quantification in lignin pyrolysis, combustion and organic synthesis.![]()
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Affiliation(s)
- Zeyou Pan
- Zeyou Pan, Andras Bodi, Jeroen A. van Bokhoven and Patrick Hemberger, Paul Scherrer Institute, 5232 Villigen, Switzerland. .,Zeyou Pan and Jeroen A. van Bokhoven, Institute for Chemical and Bioengineering, Department of Chemistry and Applied Biosciences, ETH Zurich, 8093 Zurich, Switzerland
| | - Andras Bodi
- Zeyou Pan, Andras Bodi, Jeroen A. van Bokhoven and Patrick Hemberger, Paul Scherrer Institute, 5232 Villigen, Switzerland.
| | - Jeroen A van Bokhoven
- Zeyou Pan, Andras Bodi, Jeroen A. van Bokhoven and Patrick Hemberger, Paul Scherrer Institute, 5232 Villigen, Switzerland. .,Zeyou Pan and Jeroen A. van Bokhoven, Institute for Chemical and Bioengineering, Department of Chemistry and Applied Biosciences, ETH Zurich, 8093 Zurich, Switzerland
| | - Patrick Hemberger
- Zeyou Pan, Andras Bodi, Jeroen A. van Bokhoven and Patrick Hemberger, Paul Scherrer Institute, 5232 Villigen, Switzerland.
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8
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Savee J, Sztáray B, Hemberger P, Zádor J, Bodi A, Osborn DL. Unimolecular isomerisation of 1,5-hexadiyne observed by threshold photoelectron photoion coincidence spectroscopy. Faraday Discuss 2022; 238:645-664. [DOI: 10.1039/d2fd00028h] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The unimolecular isomerisation of the prompt propargyl + propargyl "head-to-head" adduct, 1,5- hexadiyne, to fulvene and benzene by the 3,4-dimethylenecyclobut-1-ene (DMCB) intermediate (all C6H6) was studied in the high-pressure limit...
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9
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Gerlach M, Monninger S, Schleier D, Hemberger P, Goettel JT, Braunschweig H, Fischer I. Photoelectron Photoion Coincidence Spectroscopy of NCl 3 and NCl 2. Chemphyschem 2021; 22:2164-2167. [PMID: 34390518 PMCID: PMC8596423 DOI: 10.1002/cphc.202100537] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Revised: 08/10/2021] [Indexed: 12/02/2022]
Abstract
We investigate NCl3 and the NCl2 radical by photoelectron‐photoion coincidence spectroscopy using synchrotron radiation. The mass selected threshold photoelectron spectrum (ms‐TPES) of NCl3 is broad and unstructured due to the large geometry change. An ionization energy of 9.7±0.1 eV is estimated from the spectrum and supported by computations. NCl2 is generated by photolysis at 213 nm from NCl3 and its ms‐TPES shows an extended vibrational progression with a 90 meV spacing that is assigned to the symmetric N−Cl stretching mode in the cation. An adiabatic ionization energy of 9.94 ± 0.02 eV is determined.
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Affiliation(s)
- Marius Gerlach
- Institute of Physical and Theoretical Chemistry, University of Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Sophie Monninger
- Institute of Physical and Theoretical Chemistry, University of Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Domenik Schleier
- Institute of Physical and Theoretical Chemistry, University of Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Patrick Hemberger
- Laboratory for Synchrotron Radiation and Femtochemistry, Paul Scherrer Institut (PSI), 5232, Villigen, Switzerland
| | - James T Goettel
- Institute of Inorganic Chemistry and Institute for Sustainable Chemistry and Catalysis with Boron, University of Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Holger Braunschweig
- Institute of Inorganic Chemistry and Institute for Sustainable Chemistry and Catalysis with Boron, University of Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Ingo Fischer
- Institute of Physical and Theoretical Chemistry, University of Würzburg, Am Hubland, 97074, Würzburg, Germany
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10
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Genossar N, Ormond TK, Baraban JH. The matrix infrared spectra of fulvenone (C5H4=C=O) and its thermal decomposition products. Mol Phys 2021. [DOI: 10.1080/00268976.2021.1961907] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Affiliation(s)
- N. Genossar
- Department of Chemistry, Ben-Gurion University of the Negev, Beer Sheva, Israel
- Israel Atomic Energy Commission, Tel Aviv, Israel
| | - T. K. Ormond
- National Renewable Energy Laboratory, Golden, CO, USA
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, CO, USA
| | - J. H. Baraban
- Department of Chemistry, Ben-Gurion University of the Negev, Beer Sheva, Israel
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, CO, USA
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11
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Reva I, Jesus AJL, Nunes CM, Roque JPL, Fausto R. UV-Induced Photochemistry of 1,3-Benzoxazole, 2-Isocyanophenol, and 2-Cyanophenol Isolated in Low-Temperature Ar Matrixes. J Org Chem 2021; 86:6126-6137. [PMID: 33872502 DOI: 10.1021/acs.joc.0c02970] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The monomers of 1,3-benzoxazole isolated in a cryogenic argon matrix were characterized by infrared spectroscopy. The photochemistry of matrix-isolated 1,3-benzoxazole, induced by excitation with a frequency-tunable narrowband UV light, was investigated. Irradiation at 233 nm resulted in a nearly quantitative conversion of 1,3-benzoxazole into 2-isocyanophenol. The individual photochemical behavior of the in situ produced 2-isocyanophenol was studied upon excitations at 290 nm, where 1,3-benzoxazole does not react. The photochemistry of isomeric matrix-isolated 2-cyanophenol was also studied. The photoreactions of 2-substituted (cyano- or isocyano-) phenols were found to have many similarities: (i) OH bond cleavage, yielding a 2-substituted (cyano- or isocyano-) phenoxyl radical and an H-atom, (ii) recombination of the detached H-atom, resulting in an oxo tautomer, and (iii) decomposition leading to fulvenone, together with HCN and HNC. In another photoprocess, 2-cyanophenol undergoes a [1,5] H-shift from the hydroxyl group to the cyano group yielding isomeric ketenimine. The analogous [1,5] H-shift from the hydroxyl group to the isocyano group must have also occurred in 2-isocyanophenol; however, the resulting nitrile ylide isomer is kinetically unstable and collapses to benzoxazole. All photoproducts were characterized by comparing their observed infrared spectra with those computed at the B3LYP/6-311++G(d,p) level. The mechanistic analysis of the photochemistry occurring in the family of the title compounds is presented.
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Affiliation(s)
- Igor Reva
- University of Coimbra, CQC, Department of Chemistry, Coimbra 3004-535, Portugal.,University of Coimbra, CIEPQPF, Department of Chemical Engineering, Coimbra 3030-790, Portugal
| | - A J Lopes Jesus
- University of Coimbra, CQC, Faculty of Pharmacy, Coimbra 3004-295, Portugal
| | - Cláudio M Nunes
- University of Coimbra, CQC, Department of Chemistry, Coimbra 3004-535, Portugal
| | - José P L Roque
- University of Coimbra, CQC, Department of Chemistry, Coimbra 3004-535, Portugal
| | - Rui Fausto
- University of Coimbra, CQC, Department of Chemistry, Coimbra 3004-535, Portugal
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12
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Wu X, Zhou X, Bjelić S, Hemberger P, Bodi A. Valence Photoionization and Energetics of Vanillin, a Sustainable Feedstock Candidate. J Phys Chem A 2021; 125:3327-3340. [PMID: 33872037 DOI: 10.1021/acs.jpca.1c00876] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We studied the valence photoionization of vanillin by photoelectron photoion coincidence spectroscopy in the 8.20-19.80 eV photon energy range. Vertical ionization energies by EOM-IP-CCSD calculations reproduce the photoelectron spectral features. Composite method calculations and Franck-Condon simulation of the weak, ground-state band yield the adiabatic ionization energy of the most stable vanillin conformer as 8.306(20) eV. The lowest energy dissociative photoionization channels correspond to hydrogen atom, carbon monoxide, and methyl losses, which form the dominant C8H7O3+ (m/z 151) and the less intense C7H8O2+ (m/z 124) and C7H5O3+ (m/z 137) fragment ions in parallel dissociation channels at modeled 0 K appearance energies of 10.13(1), 10.40(3), and 10.58(10) eV, respectively. On the basis of the breakdown diagram, we explore the energetics of sequential methyl and carbon monoxide loss channels, which dominate the fragmentation mechanism at higher photon energies. The 0 K appearance energy for sequential CO loss from the m/z 151 fragment to C7H7O2+ (m/z 123) is 12.99(10) eV, and for sequential CH3 loss from the m/z 123 fragment to C6H4O2+ (m/z 108), it is 15.40(20) eV based on the model. Finally, we review the thermochemistry of the bi- and trifunctionalized benzene derivatives guaiacol, hydroxybenzaldehyde, anisaldehyde, and vanillin. On the basis of isodesmic functional group exchange reactions, we propose new enthalpies of formations, among them ΔfH°298K(vanillin, g) = -383.5 ± 2.9 kJ mol-1. These mechanistic insights and ab initio thermochemistry results will support analytical works to study lignin conversion involving vanillin.
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Affiliation(s)
- Xiangkun Wu
- Paul Scherrer Institute, 5232 Villigen, Switzerland.,Hefei National Laboratory for Physical Sciences at the Microscale, Department of Chemical Physics, University of Science and Technology of China, Hefei 230026, China
| | - Xiaoguo Zhou
- Hefei National Laboratory for Physical Sciences at the Microscale, Department of Chemical Physics, University of Science and Technology of China, Hefei 230026, China
| | - Saša Bjelić
- Paul Scherrer Institute, 5232 Villigen, Switzerland
| | | | - Andras Bodi
- Paul Scherrer Institute, 5232 Villigen, Switzerland
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Bouwman J, Hrodmarsson HR, Ellison GB, Bodi A, Hemberger P. Five Birds with One Stone: Photoelectron Photoion Coincidence Unveils Rich Phthalide Pyrolysis Chemistry. J Phys Chem A 2021; 125:1738-1746. [PMID: 33616395 DOI: 10.1021/acs.jpca.1c00149] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Phthalide pyrolysis has been assumed to be a clean fulvenallene source. We show that this is only true at low temperatures, and the C7H6 isomers 1-, 2-, and 5-ethynylcyclopentadiene are also formed at high pyrolysis temperatures. Photoion mass-selected threshold photoelectron spectra are analyzed with the help of (time-dependent) density functional theory, (TD-)DFT, and equation-of-motion ionization potential coupled cluster, EOM-IP-CCSD, calculations, as well as Franck-Condon simulations of partly overlapping bands, to determine ionization energies. The fulvenallene ionization energy is confirmed at 8.23 ± 0.01 eV, and the ionization energies of 1-, 2 and 5-ethynylcyclopentadiene are newly determined at 8.27 ± 0.01, 8.49 ± 0.01 and 8.76 ± 0.02 eV, respectively. Excited state features in the photoelectron spectrum, in particular the Ã+ 2A' band of 1-ethynylcyclopentadiene, are shown to be practical to isomer-selectively detect species when the ground-state band is congested. At high pyrolysis temperatures, the C7H6 isomers may lose a hydrogen atom and yield the fulvenallenyl radical. Its ionization energy is confirmed at 8.20 ± 0.01 eV. The vibrational fingerprint of the first triplet fulvenallenyl cation state is also revealed and yields an ionization energy of 8.33 ± 0.02 eV. Further triplet cation states are identified and modeled in the 10-11 eV range. A reaction mechanism is proposed based on potential energy surface calculations. Based on a simplified reactor model, we show that the C7H6 isomer distribution is far from thermal equilibrium in the reactor, presumably because irreversible H loss competes efficiently with isomerization.
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Affiliation(s)
- Jordy Bouwman
- Laboratory for Astrophysics, Leiden Observatory, Leiden University, PO Box 9513, 2300 RA Leiden, The Netherlands
| | - Helgi R Hrodmarsson
- Laboratory for Astrophysics, Leiden Observatory, Leiden University, PO Box 9513, 2300 RA Leiden, The Netherlands
| | - G Barney Ellison
- Department of Chemistry and Biochemistry, University of Colorado Boulder, Boulder, Colorado 80309-0215, United States
| | - Andras Bodi
- Laboratory for Synchrotron Radiation and Femtochemistry, Paul Scherrer Institute, 5232 Villigen, Switzerland
| | - Patrick Hemberger
- Laboratory for Synchrotron Radiation and Femtochemistry, Paul Scherrer Institute, 5232 Villigen, Switzerland
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Pan Z, Puente-Urbina A, Bodi A, van Bokhoven JA, Hemberger P. Isomer-dependent catalytic pyrolysis mechanism of the lignin model compounds catechol, resorcinol and hydroquinone. Chem Sci 2021; 12:3161-3169. [PMID: 34164083 PMCID: PMC8179379 DOI: 10.1039/d1sc00654a] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Accepted: 02/05/2021] [Indexed: 12/26/2022] Open
Abstract
The catalytic pyrolysis mechanism of the initial lignin depolymerization products will help us develop biomass valorization strategies. How does isomerism influence reactivity, product formation, selectivities, and side reactions? By using imaging photoelectron photoion coincidence (iPEPICO) spectroscopy with synchrotron radiation, we reveal initial, short-lived reactive intermediates driving benzenediol catalytic pyrolysis over H-ZSM-5 catalyst. The detailed reaction mechanism unveils new pathways leading to the most important products and intermediates. Thanks to the two vicinal hydroxyl groups, catechol (o-benzenediol) is readily dehydrated to form fulvenone, a reactive ketene intermediate, and exhibits the highest reactivity. Fulvenone is hydrogenated on the catalyst surface to phenol or is decarbonylated to produce cyclopentadiene. Hydroquinone (p-benzenediol) mostly dehydrogenates to produce p-benzoquinone. Resorcinol, m-benzenediol, is the most stable isomer, because dehydration and dehydrogenation both involve biradicals owing to the meta position of the hydroxyl groups and are unfavorable. The three isomers may also interconvert in a minor reaction channel, which yields small amounts of cyclopentadiene and phenol via dehydroxylation and decarbonylation. We propose a generalized reaction mechanism for benzenediols in lignin catalytic pyrolysis and provide detailed mechanistic insights on how isomerism influences conversion and product formation. The mechanism accounts for processes ranging from decomposition reactions to molecular growth by initial polycyclic aromatic hydrocarbon (PAH) formation steps to yield, e.g., naphthalene. The latter involves a Diels-Alder dimerization of cyclopentadiene, isomerization, and dehydrogenation.
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Affiliation(s)
- Zeyou Pan
- Laboratory for Synchrotron Radiation and Femtochemistry, Paul Scherrer Institute 5232 Villigen Switzerland
- Institute for Chemical and Bioengineering, Department of Chemistry and Applied Biosciences, ETH Zurich 8093 Zurich Switzerland
| | - Allen Puente-Urbina
- Institute for Chemical and Bioengineering, Department of Chemistry and Applied Biosciences, ETH Zurich 8093 Zurich Switzerland
| | - Andras Bodi
- Laboratory for Synchrotron Radiation and Femtochemistry, Paul Scherrer Institute 5232 Villigen Switzerland
| | - Jeroen A van Bokhoven
- Institute for Chemical and Bioengineering, Department of Chemistry and Applied Biosciences, ETH Zurich 8093 Zurich Switzerland
- Laboratory for Catalysis and Sustainable Chemistry, Paul Scherrer Institute 5232 Villigen Switzerland
| | - Patrick Hemberger
- Laboratory for Synchrotron Radiation and Femtochemistry, Paul Scherrer Institute 5232 Villigen Switzerland
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