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Wang H, Guan J, Gao J, Zhang J, Xu Q, Xu G, Jiang L, Xing L, Truhlar DG, Wang Z. Direct Observation of Covalently Bound Clusters in Resonantly Stabilized Radical Reactions and Implications for Carbonaceous Particle Growth. J Am Chem Soc 2024; 146:13571-13579. [PMID: 38710105 DOI: 10.1021/jacs.4c03417] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/08/2024]
Abstract
Based on quantum mechanically guided experiments that observed elusive intermediates in the domain of inception that lies between large molecules and soot particles, we provide a new mechanism for the formation of carbonaceous particles from gas-phase molecular precursors. We investigated the clustering behavior of resonantly stabilized radicals (RSRs) and their interactions with unsaturated hydrocarbons through a combination of gas-phase reaction experiments and theoretical calculations. Our research directly observed a sequence of covalently bound clusters (CBCs) as key intermediates in the evolution from small RSRs, such as benzyl (C7H7), indenyl (C9H7), 1-methylnaphthyl (1-C11H9), and 2-methylnaphthyl (2-C11H9), to large polycyclic aromatic hydrocarbons (PAHs) consisting of 28 to 55 carbons. We found that hydrogen abstraction and RSR addition drive the formation and growth of CBCs, leading to progressive H-losses, the generation of large PAHs and PAH radicals, and the formation of white smoke (incipient carbonaceous particles). This mechanism of progressive H-losses from CBCs (PHLCBC) elucidates the crucial relationship among RSRs, CBCs, and PAHs, and this study provides an unprecedentedly seamless path of observed assembly from small RSRs to large nanoparticles. Understanding the PHLCBC mechanism over a wide temperature range may enhance the accuracy of multiscale models of soot formation, guide the synthesis of carbonaceous nanomaterials, and deepen our understanding of the origin and evolution of carbon within our galaxy.
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Affiliation(s)
- Hong Wang
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230029, Anhui, P. R. China
| | - Jiwen Guan
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230029, Anhui, P. R. China
| | - Jiao Gao
- Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, P. R. China
| | - Jinyang Zhang
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230029, Anhui, P. R. China
| | - Qiang Xu
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230029, Anhui, P. R. China
| | - Guangxian Xu
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230029, Anhui, P. R. China
| | - Ling Jiang
- Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, P. R. China
| | - Lili Xing
- Energy and Power Engineering Institute, Henan University of Science and Technology, Luoyang 471003, Henan, P. R. China
| | - Donald G Truhlar
- Department of Chemistry, Chemical Theory Center, and Minnesota Supercomputing Institute, University of Minnesota, Minneapolis, Minnesota 55455-0431, United States
| | - Zhandong Wang
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230029, Anhui, P. R. China
- State Key Laboratory of Fire Science, University of Science and Technology of China, Hefei 230026, Anhui, P. R. China
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2
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Matsugi A, Suzuki S. Ring Growth Mechanism in the Reaction between Fulvenallenyl and Cyclopentadienyl Radicals. J Phys Chem A 2024; 128:1327-1338. [PMID: 38351621 DOI: 10.1021/acs.jpca.3c07441] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/23/2024]
Abstract
Recombination between resonance-stabilized hydrocarbon radicals is an important class of reactions that contribute to molecular growth chemistry in combustion. In the present study, the ring growth mechanism in the reaction between fulvenallenyl (C7H5) and cyclopentadienyl (C5H5) radicals is investigated computationally. The reaction pathways are explored by quantum chemical calculations, and the phenomenological and steady-state rate constants are determined by solving the multiple-well master equations. The primary reaction routes following the recombination between the two radicals are found to be as follows: formation of the adducts, isomerization by hydrogen shift reactions, cyclization to form tricyclic compounds, and their isomerization and dissociation reactions, leading to the formation of acenaphthylene. The overall process can be approximately represented as C7H5 + C5H5 → acenaphthylene + 2H with the bimolecular rate constant of about 4 × 10-12 cm3 molecule-1 s-1. A reaction mechanism consisting of 20 reactions, including the formation, isomerization, and dissociation processes of major intermediate species, is proposed for use in kinetic modeling.
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Affiliation(s)
- Akira Matsugi
- Research Institute of Science for Safety and Sustainability, National Institute of Advanced Industrial Science and Technology (AIST), 16-1 Onogawa, Tsukuba 305-8569, Japan
| | - Shunsuke Suzuki
- Research Institute for Energy Conversion, National Institute of Advanced Industrial Science and Technology (AIST), 1-2-1 Namiki, Tsukuba 305-8564, Japan
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He C, Kaiser RI, Lu W, Ahmed M, Pivovarov PS, Kuznetsov OV, Zagidullin MV, Mebel AM. Unconventional Pathway in the Gas-Phase Synthesis of 9H-Fluorene (C 13 H 10 ) via the Radical-Radical Reaction of Benzyl (C 7 H 7 ) with Phenyl (C 6 H 5 ). Angew Chem Int Ed Engl 2023; 62:e202216972. [PMID: 36524679 DOI: 10.1002/anie.202216972] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2022] [Revised: 12/16/2022] [Accepted: 12/16/2022] [Indexed: 12/23/2022]
Abstract
The simplest polycyclic aromatic hydrocarbon (PAH) carrying a five-membered ring-9H-fluorene (C13 H10 )-is produced isomer-specifically in the gas phase by reacting benzyl (C7 H7 ⋅) with phenyl (C6 H5 ⋅) radicals in a pyrolytic reactor coupled with single photon ionization mass spectrometry. The unconventional mechanism of reaction is supported by theoretical calculations, which first produces diphenylmethane and unexpected 1-(6-methylenecyclohexa-2,4-dienyl)benzene intermediates (C13 H12 ) accessed via addition of the phenyl radical to the ortho position of the benzyl radical. These findings offer convincing evidence for molecular mass growth processes defying conventional wisdom that radical-radical reactions are initiated through recombination at their radical centers. The structure of 9H-fluorene acts as a molecular building block for complex curved nanostructures like fullerenes and nanobowls providing fundamental insights into the hydrocarbon evolution in high temperature settings.
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Affiliation(s)
- Chao He
- Department of Chemistry, University of Hawai'i at Mānoa, Honolulu, HI-96822, USA
| | - Ralf I Kaiser
- Department of Chemistry, University of Hawai'i at Mānoa, Honolulu, HI-96822, USA
| | - Wenchao Lu
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA-94720, USA
| | - Musahid Ahmed
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA-94720, USA
| | - Pavel S Pivovarov
- Samara National Research University, Samara, 443086, Russian Federation
| | - Oleg V Kuznetsov
- Samara National Research University, Samara, 443086, Russian Federation
| | | | - Alexander M Mebel
- Department of Chemistry and Biochemistry, Florida International University, Miami, FL-33199, USA
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Hellmuth M, Chen B, Bariki C, Cai L, Cameron F, Wildenberg A, Huang C, Faller S, Ren Y, Beeckmann J, Leonhard K, Heufer KA, Hansen N, Pitsch H. A Comparative Study on the Combustion Chemistry of Two Bio-hybrid Fuels: 1,3-Dioxane and 1,3-Dioxolane. J Phys Chem A 2023; 127:286-299. [PMID: 36580040 DOI: 10.1021/acs.jpca.2c06576] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Bio-hybrid fuels are a promising solution to accomplish a carbon-neutral and low-emission future for the transportation sector. Two potential candidates are the heterocyclic acetals 1,3-dioxane (C4H8O2) and 1,3-dioxolane (C3H6O2), which can be produced from the combination of biobased feedstocks, carbon dioxide, and renewable electricity. In this work, comprehensive experimental and numerical investigations of 1,3-dioxane and 1,3-dioxolane were performed to support their application in internal combustion engines. Ignition delay times and laminar flame speeds were measured to reveal the combustion chemistry on the macroscale, while speciation measurements in a jet-stirred reactor and ethylene-based counterflow diffusion flames provided insights into combustion chemistry and pollutant formation on the microscale. Comparing the experimental and numerical data using either available or proposed kinetic models revealed that the combustion chemistry and pollutant formation differ substantially between 1,3-dioxane and 1,3-dioxolane, although their molecular structures are similar. For example, 1,3-dioxane showed higher reactivity in the low-temperature regime (500-800 K), while 1,3-dioxolane addition to ethylene increased polycyclic aromatic hydrocarbons and soot formation in high-temperature (>800 K) counterflow diffusion flames. Reaction pathway analyses were performed to examine and explain the differences between these two bio-hybrid fuels, which originate from the chemical bond dissociation energies in their molecular structures.
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Affiliation(s)
- Maximilian Hellmuth
- Institute for Combustion Technology, RWTH Aachen University, 52056Aachen, Germany
| | - Bingjie Chen
- Institute for Combustion Technology, RWTH Aachen University, 52056Aachen, Germany
| | - Chaimae Bariki
- Institute for Combustion Technology, RWTH Aachen University, 52056Aachen, Germany
| | - Liming Cai
- School for Automotive Studies, Tongji University, 201804Shanghai, China
| | - Florence Cameron
- Institute for Combustion Technology, RWTH Aachen University, 52056Aachen, Germany
| | - Alina Wildenberg
- Chair of High Pressure Gas Dynamics, Shock Wave Laboratory, RWTH Aachen University, 52056Aachen, Germany
| | - Can Huang
- Institute of Technical Thermodynamics, RWTH Aachen University, 52056Aachen, Germany
| | - Sebastian Faller
- Institute for Combustion Technology, RWTH Aachen University, 52056Aachen, Germany
| | - Yihua Ren
- Institute for Combustion Technology, RWTH Aachen University, 52056Aachen, Germany
| | - Joachim Beeckmann
- Institute for Combustion Technology, RWTH Aachen University, 52056Aachen, Germany
| | - Kai Leonhard
- Institute of Technical Thermodynamics, RWTH Aachen University, 52056Aachen, Germany
| | - Karl Alexander Heufer
- Chair of High Pressure Gas Dynamics, Shock Wave Laboratory, RWTH Aachen University, 52056Aachen, Germany
| | - Nils Hansen
- Combustion Research Facility, Sandia National Laboratories, Livermore, California94551, United States
| | - Heinz Pitsch
- Institute for Combustion Technology, RWTH Aachen University, 52056Aachen, Germany
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The Accuracy of Semi-Empirical Quantum Chemistry Methods on Soot Formation Simulation. Int J Mol Sci 2022; 23:ijms232113371. [DOI: 10.3390/ijms232113371] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Revised: 10/29/2022] [Accepted: 10/30/2022] [Indexed: 11/06/2022] Open
Abstract
Soot molecules are hazardous compounds threatening human health. Computational chemistry provides efficient tools for studying them. However, accurate quantum chemistry calculation is costly for the simulation of large-size soot molecules and high-throughput calculations. Semi-empirical (SE) quantum chemistry methods are optional choices for balancing computational costs. In this work, we validated the performances of several widely used SE methods in the description of soot formation. Our benchmark study focuses on, but is not limited to, the validation of the performances of SE methods on reactive and non-reactive MD trajectory calculations. We also examined the accuracy of SE methods of predicting soot precursor structures and energy profiles along intrinsic reaction coordinate(s) (IRC). Finally, we discussed the spin density predicted by SE methods. The SE methods validated include AM1, PM6, PM7, GFN2-xTB, DFTB2, with or without spin-polarization, and DFTB3. We found that the shape of MD trajectory profiles, the relative energy, and molecular structures predicted by SE methods are qualitatively correct. We suggest that SE methods can be used in massive reaction soot formation event sampling and primary reaction mechanism generation. Yet, they cannot be used to provide quantitatively accurate data, such as thermodynamic and reaction kinetics ones.
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Gao H, Tang H. Temperature Effect on Formation of Polycyclic Aromatic Hydrocarbons in Acetylene Pyrolysis. ChemistrySelect 2022. [DOI: 10.1002/slct.202201893] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- He Gao
- College of Energy and Power Engineering Nanjing University of Aeronautics and Astronautics 29-Yudao St. Nanjing 210016, Jiangsu Province China
| | - Hao Tang
- College of Energy and Power Engineering Nanjing University of Aeronautics and Astronautics 29-Yudao St. Nanjing 210016, Jiangsu Province China
- Aero-engine Thermal Environment and Structure Key Laboratory of Ministry of Industry and Information Technology Nanjing University of Aeronautics and Astronautics Nanjing 210016, Jiangsu Province China
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Zhou Z, Yang J, Yuan W, Wang Z, Pan Y, Qi F. Probing combustion and catalysis intermediates by synchrotron vacuum ultraviolet photoionization molecular-beam mass spectrometry: recent progress and future opportunities. Phys Chem Chem Phys 2022; 24:21567-21577. [DOI: 10.1039/d2cp02899a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Soft photoionization molecular-beam mass spectrometry (PI MBMS) with synchrotron vacuum ultraviolet light (SVUV) has has a significant development and broad applications in recent decades. Particularly, the tunability of SVUV enables...
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