Article
Chemistry, Multidisciplinary
Denisia M. Popolan-Vaida, Arkke J. Eskola, Brandon Rotavera, Jessica F. Lockyear, Zhandong Wang, S. Mani Sarathy, Rebecca L. Caravan, Judit Zador, Leonid Sheps, Arnas Lucassen, Kai Moshammer, Philippe Dagaut, David L. Osborn, Nils Hansen, Stephen R. Leone, Craig A. Taatjes
Summary: The decomposition of ketohydroperoxides (KHP) to formic acid and acetone was studied, revealing that the KHP concentration decreases with increasing temperature while formic acid and acetone products increase. Isotopologs observation suggests the involvement of the Korcek mechanism.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Article
Chemistry, Physical
Rajbeer Singh, Satyendra Pal
Summary: Energy-dependent partial differential ionization cross sections and integral cross sections for n-butane by electron impact corresponding to the formation of various major cations are calculated using a revisited Jain-Khare semiempirical formulation. Averaged energies of the secondary electrons are also derived. Ionization rate coefficients are evaluated as a function of temperature. The calculated partial and total ionization cross sections show satisfactory agreement with experimental and theoretical results.
JOURNAL OF PHYSICAL CHEMISTRY A
(2021)
Article
Thermodynamics
Jiabin Huang, Can Huang, Qifeng Hou, Mengqi Wu, Xiaoqing Wu, Yaogang Zhang, Guangjun Tian, Feng Zhang
Summary: In this study, the dissociative photoionization mechanism of KHP was investigated using quantum chemical calculations and experimental comparisons. The findings reveal potential biases in the collection of KHP signals and provide valuable insights for improving the quantification of KHP in analysis methods.
COMBUSTION AND FLAME
(2023)
Article
Thermodynamics
Samuel W. Hartness, Nicholas S. Dewey, Matthew G. Christianson, Alanna L. Koritzke, Anna C. Doner, Annabelle R. Webb, Brandon Rotavera
Summary: The degenerate chain-branching mechanisms of n-alkanes involve the formation of hydroperoxy-alkyl radicals ((Q)Over dotOOH) through (R)Over dot + O-2 reactions, leading to a competition between unimolecular decomposition and second-O-2-addition. The quantitative measurements of partially oxidized intermediates formed from (Q)Over dotOOH reactions provide critical constraints for accurate modeling of combustion chemistry. The influence of temperature and oxygen concentration on intermediates from the unimolecular decomposition of (Q)Over dotOOH was examined, and the O-2-dependence of species profiles was quantified.
PROCEEDINGS OF THE COMBUSTION INSTITUTE
(2023)
Article
Thermodynamics
Chao Peng, Chun Zou, Wenxiang Xia, Qianjin Lin, Jianghui Luo, Haiyang Shi, Lixin Lu, Shusen Wang
Summary: Pressurized oxy-fuel combustion is considered an advanced technique with lower cost and little decrease in efficiency compared to conventional PC systems without CO2 capture. Experimental and modeling work on n-butane ignition delay times under different conditions validates the updated chemical kinetic model Oxymech2.0 Plus, which shows improved prediction accuracy for butane combustion in O2 / CO2 atmospheres. The effects of equivalence ratios and CO2 concentrations on the ignition delay times of n-butane were analyzed.
COMBUSTION AND FLAME
(2021)
Article
Chemistry, Physical
Yanbo Li, Weiye Chen, Long Zhu, Huanhuan Wang, Jiwen Guan, Xiaobin Shan, Fuyi Liu, Zhandong Wang
Summary: The study focused on the photoionization and dissociation processes of BVOC MBO232, demonstrating a rare CH3 migration towards the cation. This phenomenon was explained through quantum chemistry calculations and molecular orbital analysis.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2021)
Article
Thermodynamics
Weiye Chen, Qiang Xu, Hao Lou, Qimei Di, Cheng Xie, Bingzhi Liu, Jiuzhong Yang, Herve Le Gall, L. S. Tran, Xudi Wang, Zongyu Xia, Olivier Herbinet, Frederique Battin-Leclerc, Zhandong Wang
Summary: Low temperature oxidation chemistry is important in the auto-ignition process of internal combustion engines. This study develops a variable pressure jet-stirred reactor (VPJSR) platform and probes intermediates using synchrotron vacuum ultraviolet photoionization mass spectrometry. The setup is validated by repeating experiments and shows good agreement with literature data. The VP-JSR system is valuable for studying fuel chemistry and guiding the development of reaction systems at high pressures.
COMBUSTION AND FLAME
(2022)
Article
Thermodynamics
Tongpo Yu, Qiang Xu, Hong Wang, Cheng Xie, Jiwen Guan, Xiaoguo Zhou, Zhandong Wang
Summary: An in-depth investigation of the thermal decomposition mechanism of n-pentyl nitrate was conducted through experimental and computational studies. Intermediate products and mechanisms were identified using synchrotron radiation vacuum ultraviolet photoionization and quantum chemical calculations. The results suggest that both bond fission and hydrogen migration play important roles in the pyrolysis of n-pentyl nitrate.
COMBUSTION AND FLAME
(2023)
Article
Thermodynamics
Wang Li, Jiu-Zhong Yang, Long Zhao, Dan Yu, Zhen-Yu Tian
Summary: The pyrolysis of n-propylamine (NPA) was studied using tunable synchrotron photoionization and molecular-beam mass spectrometry techniques. A comprehensive kinetic model with 405 species and 2668 reactions was developed. Results indicate that H-abstractions play a major role in NPA consumption, while reactions CH3 + CH3 = C2H5 + H and CH3CHCHNH2 + H = CH2CHCHNH2 + H-2 tend to have inhibiting effects on NPA consumption.
COMBUSTION AND FLAME
(2021)
Article
Chemistry, Physical
Anna C. Doner, Nicholas S. Dewey, Brandon Rotavera
Summary: Alkyl-substituted cyclic ethers are intermediates formed during low-temperature oxidation, and understanding their reactions is critical for numerical modeling of combustion. Cl-initiated oxidation experiments on 2-methyloxetane were conducted, revealing complex reactions including ring opening and formation of hydroperoxy-substituted carbon radicals. The results highlight the complexity of cyclic ethers and the need for improved chemical kinetic models for combustion.
JOURNAL OF PHYSICAL CHEMISTRY A
(2023)
Article
Chemistry, Physical
Domenik Schleier, Engelbert Reusch, Marius Gerlach, Tobias Preitschopf, Deb Pratim Mukhopadhyay, Nancy Fassheber, Gernot Friedrichs, Patrick Hemberger, Ingo Fischer
Summary: The reaction kinetics of different isomers of the methylallyl radical with molecular oxygen was studied, with findings on rate constants and pressure dependences.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2021)
Article
Chemistry, Physical
Yanbo Li, Jiwen Guan, Huanhuan Wang, Long Zhu, Lili Ye, Zhandong Wang
Summary: The reactions of 2-Methyl-3-buten-2-ol (MBO232) with OH radicals under various combustion conditions were studied. It was found that OH-addition reactions dominate at lower temperatures, while H-abstraction reactions are more competitive at higher temperatures, especially when abstracting H atoms from methyl groups. Discrimination of H atoms attached to the same C atom is necessary as their abstraction rates can differ significantly. The calculated results showed good agreement with experimental data and provided valuable kinetic data for building combustion models and understanding the combustion kinetics of unsaturated alcohols.
JOURNAL OF PHYSICAL CHEMISTRY A
(2021)
Article
Thermodynamics
Haodong Chen, Ruzheng Zhang, Handong Liao, Zhongkai Liu, Zhaoying Li, Feng Zhang, Jiuzhong Yang, Bin Yang
Summary: The chemical kinetics of plasma-assisted low-temperature oxidation of n-butane was studied using SVUV-PIMS and kinetic modeling. Species measurements were conducted in a flow reactor activated by a nanosecond discharge. Fuel-specific oxygenated species were identified and quantified. A kinetic model for n-C4H10 plasma was developed and well predicted the observed species. Electron-impact reactions and alkyl peroxy reactions were found to be the main sources and depletion routes for various species. However, the formation pathways of some detected species were incompletely described.
APPLICATIONS IN ENERGY AND COMBUSTION SCIENCE
(2023)
Article
Mechanics
Jesse W. Streicher, Ajay Krish, Ronald K. Hanson
Summary: The fast decomposition of nitrous oxide (N2O) into molecular nitrogen (N-2) and atomic oxygen (O) was studied to probe the N-2 + O and NO + O Zeldovich reactions. Experiments were conducted at temperatures ranging from 2000 to 6800 K and pressures ranging from 0.04 to 1.67 atm, with 1% and 5% N2O diluted in argon (Ar) or N-2. Infrared and ultraviolet laser absorption diagnostic systems were used to measure the concentrations of N2O and NO, and the results were used to infer the reaction rates.
Article
Chemistry, Multidisciplinary
Boyli Ghosh, Ambar Banerjee, Lisa Roy, Rabindra Nath Manna, Rounak Nath, Ankan Paul
Summary: This study investigates the mechanistic pathways of copper-promoted formation of aryl isocyanate from aryl aldehyde. The analysis suggests that the reaction proceeds through radical-based pathways, consistent with experimental findings. Copper salts play a role as an electron pool in this nitrogen transfer reaction.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Article
Energy & Fuels
Zachary Buras, Nils Hansen, Craig A. Taatjes, Leonid Sheps
Summary: Using chemical kinetic modeling and statistical analysis, this study examines the correlation between key chemical markers and fuel ignition properties. The feasibility of designing a fuel-screening platform based on small laboratory reactors is evaluated. Results show that first-stage ignition delay time and low-temperature heat release can be reliably predicted, but total ignition delay time prediction is less accurate.
Article
Chemistry, Multidisciplinary
Denisia M. Popolan-Vaida, Arkke J. Eskola, Brandon Rotavera, Jessica F. Lockyear, Zhandong Wang, S. Mani Sarathy, Rebecca L. Caravan, Judit Zador, Leonid Sheps, Arnas Lucassen, Kai Moshammer, Philippe Dagaut, David L. Osborn, Nils Hansen, Stephen R. Leone, Craig A. Taatjes
Summary: The decomposition of ketohydroperoxides (KHP) to formic acid and acetone was studied, revealing that the KHP concentration decreases with increasing temperature while formic acid and acetone products increase. Isotopologs observation suggests the involvement of the Korcek mechanism.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Article
Thermodynamics
David E. Couch, Goutham Kukkadapu, Angie J. Zhang, Ahren W. Jasper, Craig A. Taatjes, Nils Hansen
Summary: This study investigates the radical-radical reaction of phenyl (C6H5) and propargyl (C3H3) and finds that the propargyl radical reaction can contribute to the formation of polycyclic radicals related to soot inception. By conducting experiments and simulations, it is observed that the radical concentration is positively correlated with temperature under the conditions of 800-1600 K and 25 Torr pressure, and eliminating the radical reactions leads to a discrepancy between simulation and experiment.
PROCEEDINGS OF THE COMBUSTION INSTITUTE
(2023)
Article
Chemistry, Physical
David E. Couch, Clayton R. Mulvihill, Raghu Sivaramakrishnan, Kendrew Au, Craig A. Taatjes, Leonid Sheps
Summary: In this study, the mechanism of DME oxidation reaction was investigated experimentally and theoretically, revealing discrepancies between current models and experimental observations in terms of product formation rate and yield. By introducing new reaction pathways and adjusting rate coefficients, the predictive capability of the existing models can be improved.
JOURNAL OF PHYSICAL CHEMISTRY A
(2022)
Article
Chemistry, Physical
Oliver Welz, Mark Pfeifle, Patrick M. Plehiers, Rebecca Sure, Peter Deglmann
Summary: This study investigates the gas-phase reaction of isocyanates with the OH radical using quantum chemistry and transition state theory. The results show that OH addition to the aromatic ring of isocyanates is a major reaction pathway compared to OH addition to the isocyanate group.
JOURNAL OF PHYSICAL CHEMISTRY A
(2022)
Article
Chemistry, Physical
Daniel Rosch, Gregory H. Jones, Raybel Almeida, Rebecca L. Caravan, Aileen Hui, Amelia W. Ray, Carl J. Percival, Stanley P. Sander, Matthew D. Smarte, Frank A. F. Winiberg, Mitchio Okumura, David L. Osborn
Summary: The concentration of formic acid in Earth's troposphere is underestimated by chemical models. Phototautomerization of acetaldehyde to vinyl alcohol, followed by OH-initiated oxidation, is proposed as a missing source of formic acid. The reaction between OH and vinyl alcohol is influenced by the conformeric structure, with different theoretical studies reaching different conclusions. Our study uses mass spectrometry to show that the glycoaldehyde product channel dominates over formic acid production, supporting the role of conformer-dependent hydrogen bonding.
JOURNAL OF PHYSICAL CHEMISTRY A
(2023)
Article
Chemistry, Physical
Talitha M. Selby, Fabien Goulay, Satchin Soorkia, Amelia Ray, Ahren W. Jasper, Stephen J. Klippenstein, Alexander N. Morozov, Alexander M. Mebel, John D. Savee, Craig A. Taatjes, David L. Osborn
Summary: The mechanism of hydrocarbon ring growth in sooting environments is still debated. This study investigates the reaction between phenyl radical and propargyl radical and finds that at temperatures of 300-1000 K, two isomers, C9H8 and C9H7 + H, are formed. Further calculations and experiments suggest that the involvement of H atoms contributes to the formation of polycyclic aromatic hydrocarbon's second ring.
JOURNAL OF PHYSICAL CHEMISTRY A
(2023)
Article
Chemistry, Physical
Daniel Rosch, Yifei Xu, Hua Guo, Xixi Hu, David L. Osborn
Summary: We provide experimental evidence of a new photodissociation pathway of SO2, resulting in the production of S(P-3(j)) + O-2 X(S-3(g)-) with a yield of 2-4%. High-level ab initio calculations suggest that this pathway occurs through internal conversion from the excited state followed by isomerization to a transient SOO intermediate. Classical trajectory simulations qualitatively reproduce the experimental yields, indicating the significance of this unexpected photodissociation pathway in understanding Earth's geologic history and atmospheric evolution.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2023)
Article
Chemistry, Physical
Meijun Zou, Tianlin Liu, Michael F. Vansco, Christopher A. Sojdak, Charles R. Markus, Raybel Almeida, Kendrew Au, Leonid Sheps, David L. Osborn, Frank A. F. Winiberg, Carl J. Percival, Craig A. Taatjes, Stephen J. Klippenstein, Marsha I. Lester, Rebecca L. Caravan
Summary: Methyl-ethyl-substituted Criegee intermediate (MECI) is a carbonyl oxide formed in the ozonolysis of asymmetric alkenes. It lacks resonance stabilization and reacts faster with SO2 compared to MVK-oxide + SO2, indicating the significant influence of resonance stabilization on Criegee intermediate reactivity.
JOURNAL OF PHYSICAL CHEMISTRY A
(2023)
Article
Chemistry, Multidisciplinary
Tianlin Liu, Sarah N. Elliott, Meijun Zou, Michael F. Vansco, Christopher A. Sojdak, Charles R. Markus, Raybel Almeida, Kendrew Au, Leonid Sheps, David L. Osborn, Frank A. F. Winiberg, Carl J. Percival, Craig A. Taatjes, Rebecca L. Caravan, Stephen J. Klippenstein, Marsha I. Lester
Summary: Alkene ozonolysis can produce Criegee intermediates, which are important sources of hydroxyl radicals. This study shows that the roaming of separating hydroxyl radicals can result in the formation of alternate hydroxycarbonyl products, leading to a reduction in the yield of hydroxyl radicals. Experimental and theoretical analyses demonstrate that hydroxybutanone is a stable product formed from the roaming of the methyl-ethyl-substituted Criegee intermediate (MECI), and the dynamics of the multistage dissociation process have been investigated.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Chemistry, Physical
Daniel Rosch, Gregory H. Jones, Raybel Almeida, Rebecca L. Caravan, Aileen Hui, Amelia W. Ray, Carl J. Percival, Stanley P. Sander, Matthew D. Smarte, Frank A. F. Winiberg, Mitchio Okumura, David L. Osborn
Summary: The concentration of formic acid in Earth's troposphere is underestimated by chemical models compared to field observations. Phototautomerization of acetaldehyde to vinyl alcohol followed by OH-initiated oxidation of vinyl alcohol is proposed as a missing source of formic acid. The reaction pathway of OH addition is controlled by the conformeric structure of vinyl alcohol.
JOURNAL OF PHYSICAL CHEMISTRY A
(2023)
Article
Chemistry, Physical
Talitha M. Selby, Fabien Goulay, Satchin Soorkia, Amelia Ray, Ahren W. Jasper, Stephen J. Klippenstein, Alexander N. Morozov, Alexander M. Mebel, John D. Savee, Craig A. Taatjes, David L. Osborn
Summary: The reaction mechanism of hydrocarbon ring growth in sooting environments is still a topic of debate. This study focuses on the reaction between phenyl radical and propargyl radical, and investigates the effect of temperature on product formation. Experimental data and theoretical calculations suggest that as temperature increases, additional isomers are formed, potentially due to the contribution of hydrogen atom reactions.
JOURNAL OF PHYSICAL CHEMISTRY A
(2023)
Article
Chemistry, Multidisciplinary
Tianlin Liu, Sarah N. Elliott, Meijun Zou, Michael F. Vansco, Christopher A. Sojdak, Charles R. Markus, Raybel Almeida, Kendrew Au, Leonid Sheps, David L. Osborn, Frank A. F. Winiberg, Carl J. Percival, Craig A. Taatjes, Rebecca L. Caravan, Stephen J. Klippenstein, Marsha I. Lester
Summary: Alkene ozonolysis generates short-lived Criegee intermediates, which are a significant source of hydroxyl radicals. This study demonstrates that roaming of the separating OH radicals can yield alternate hydroxycarbonyl products, thereby reducing the OH yield. Specifically, hydroxybutanone has been detected as a stable product arising from roaming in the unimolecular decay of certain Criegee intermediates. The mechanism of hydroxybutanone formation has been investigated through theoretical calculations and experimental methods.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)