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Zhang H, Wang J, Dong B, Xu F, Liu H, Zhang Q, Zong W, Shi X. New mechanism for the participation of aromatic oxidation products in atmospheric nucleation. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 917:170487. [PMID: 38296079 DOI: 10.1016/j.scitotenv.2024.170487] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2023] [Revised: 01/03/2024] [Accepted: 01/24/2024] [Indexed: 02/03/2024]
Abstract
Oxygenated organic molecules (OOMs) are recognized as important precursors for new particle formation (NPF) in the urban atmosphere. The paper theoretically studied the formation of OOMs by styrene oxidation processes initiated by OH radicals, focusing on the OOMs nucleation mechanism. The results found that in the presence of an H2SO4 molecule, lowly oxygenated organic molecules containing a benzene ring (LOMBs) can form stable clusters and grow to the scale of a critical nucleus through pi-pi stacking and OH hydrogen bonding. In addition, LOMBs are more readily generated in a styrene-oxidized system in the presence/absence of NOx than highly oxygenated organic molecules (HOMs). The reaction of OH radicals with other aromatics containing a branched chain on the benzene ring produces LOMBs to varying degrees, with pi-pi stacking playing an essential role. This result suggests that, in the presence of H2SO4 molecules, LOMBs may play a more significant role in promoting nucleation than HOMs. Our findings serve as a pivotal foundation for future investigations into the oxidation and nucleation processes of diverse aromatics in urban environments.
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Affiliation(s)
- Huidi Zhang
- College of Geography and Environment, Shandong Normal University, Jinan 250014, PR China
| | - Juanbao Wang
- College of Geography and Environment, Shandong Normal University, Jinan 250014, PR China
| | - Biao Dong
- College of Geography and Environment, Shandong Normal University, Jinan 250014, PR China
| | - Fei Xu
- Environment Research Institute, Shandong University, Qingdao 266237, PR China
| | - Houfeng Liu
- College of Geography and Environment, Shandong Normal University, Jinan 250014, PR China
| | - Qingzhu Zhang
- Environment Research Institute, Shandong University, Qingdao 266237, PR China
| | - Wansong Zong
- College of Geography and Environment, Shandong Normal University, Jinan 250014, PR China
| | - Xiangli Shi
- College of Geography and Environment, Shandong Normal University, Jinan 250014, PR China.
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Wu X, Yao X, Xie B, Wang P, Huo W, Zhu Y, Hou Q, Wu M, Wu Y, Zhang F. Unraveling the atmospheric oxidation mechanism and kinetics of naphthalene: Insights from theoretical exploration. CHEMOSPHERE 2024; 352:141356. [PMID: 38309603 DOI: 10.1016/j.chemosphere.2024.141356] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2023] [Revised: 01/28/2024] [Accepted: 01/31/2024] [Indexed: 02/05/2024]
Abstract
Naphthalene, the most abundant polycyclic aromatic hydrocarbon in the atmosphere, significantly influences OH consumption and secondary organic aerosol (SOA) formation. Naphthoquinone (NQ) is a significant contributor to ring-retaining SOA from naphthalene degradation, impacting the redox properties and toxicity of ambient particles. However, inconsistencies persist regarding concentrations of its isomers, 1,2-NQ and 1,4-NQ. In present work, our theoretical investigation into naphthalene's reaction with OH and subsequent oxygenation unveils their role in SOA formation. The reaction kinetics of initial OH and subsequent O2 oxidation was extensively studied using high-level quantum chemical methods (DLPNO-CCSD(T)/aug-ccpVQZ//M052x-D3/6-311++G(d,p)) combined with RRKM/master equation simulations. The reactions mainly proceed through electrophilic addition and abstraction from the aromatic ring. The total rate coefficient of naphthalene + OH at 300 K and 1 atm from our calculation (7.2 × 10-12 cm3 molecule-1 s-1) agrees well with previous measurements (∼1 × 10-11 cm3 molecule-1 s-1). The computed branching ratios facilitate accurate product yield determination. The largest yield of 1-hydroxynaphthalen-1-yl radical (add1) producing the major precursor of RO2 is computed to be 93.8 % in the ambient environment. Our calculated total rate coefficient (5.2 × 10-16 cm3 molecule-1 s-1) for add1 + O2 closely matches that of limited experimental data (8.0 × 10-16 cm3 molecule-1 s-1). Peroxy radicals (RO2) generated from add1 + O2 include 4-cis/trans-(1-hydroxynaphthalen-1-yl)-peroxy radical (add1-4OOadd-cis/trans, 66.0 %/17.5 %), 2-cis/trans-(1-hydroxynaphthalen-1-yl)-peroxy radical (add1-2OOadd-cis/trans, 10.3 %/6.3 %). Regarding the debated predominance of 1,4-NQ (corresponding to the parent RO2, i.e., add1-4OOadd-cis/trans) and 1,2-NQ (corresponding to the parent RO2, i.e., add1-2OOadd-cis/trans) in the atmosphere, our findings substantiate the dominance of 1,4-NQ. This study also indicates potential weakening of 1,4-NQ's dominance due to competition from decomposition reactions of add1-4OOadd-cis/trans and add1-2OOadd-cis/trans. Precise reaction kinetics data are essential for characterizing SOA transformation derived from naphthalene and assessing their climatic impacts within modeling frameworks.
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Affiliation(s)
- Xiaoqing Wu
- College of Information Engineering, China Jiliang University, Hangzhou, 310018, PR China; Science and Technology on Plasma Dymamics Lab, Aeronautics and Astronautics Engineering College, Air Force Engineering University, Xian, 710038, PR China.
| | - Xiaoxia Yao
- Science and Technology on Plasma Dymamics Lab, Aeronautics and Astronautics Engineering College, Air Force Engineering University, Xian, 710038, PR China.
| | - Binbin Xie
- Hangzhou Institute of Advanced Studies, Zhejiang Normal University, Hangzhou, 311231, PR China.
| | - Pengfei Wang
- National Institute of Extremely-Weak Magnetic Field Infrastructure, Hangzhou, 310051, PR China.
| | - Wanli Huo
- College of Information Engineering, China Jiliang University, Hangzhou, 310018, PR China.
| | - Yifei Zhu
- Institute of Aero-engine, School of Mechanical Engineering, Xi'an Jiaotong University, Xi'an, PR China.
| | - Qifeng Hou
- National Institute of Extremely-Weak Magnetic Field Infrastructure, Hangzhou, 310051, PR China.
| | - Mengqi Wu
- Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, Anhui, 230026, PR China; Hefei National Laboratory, University of Science and Technology of China, Hefei, Anhui, 230088, PR China.
| | - Yun Wu
- Science and Technology on Plasma Dymamics Lab, Aeronautics and Astronautics Engineering College, Air Force Engineering University, Xian, 710038, PR China.
| | - Feng Zhang
- Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, Anhui, 230026, PR China; Hefei National Laboratory, University of Science and Technology of China, Hefei, Anhui, 230088, PR China.
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Gaikwad S, Urban MW. Ring-and-Lock Interactions in Self-Healable Styrenic Copolymers. J Am Chem Soc 2023; 145:9693-9699. [PMID: 37068169 DOI: 10.1021/jacs.3c01199] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/19/2023]
Abstract
Commodity copolymers offer many useful applications, and their durability is critical in maintaining desired functions and retaining sustainability. These studies show that primarily alternating styrene/n-butyl acrylate [p(Sty/nBA)] copolymers self-heal without external intervention when monomer molar ratios are within the 45:55-53:47 range. This behavior is attributed to the favorable interchain interactions between aliphatic nBA side groups being sandwiched by aromatic rings forming ring-and-lock associations driven by pi-sigma-pi (π-σ-π) interactions. Guided by molecular dynamics (MD) simulations combined with spectroscopic and thermomechanical analysis, the ring-and-lock interchain van der Waals forces between π orbitals of aromatic rings and sigma components of aliphatic side groups are responsible for self-healing. Despite the frequent occurrence of these interactions in biological systems (proteins, nucleic acids, lipids, and polysaccharides), these largely unexplored weak and ubiquitous molecular forces between the soft acid aliphatic and soft base aromatic electrons may be valuable assets in the development of polymeric materials with sustainable properties.
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Affiliation(s)
- Samruddhi Gaikwad
- Department of Materials Science and Engineering, Clemson University, Clemson, South Carolina 29634, United States
| | - Marek W Urban
- Department of Materials Science and Engineering, Clemson University, Clemson, South Carolina 29634, United States
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Sun Y, Liu L, Li M, Chen X, Xu F. Theoretical investigation on the mechanisms and kinetics of OH/NO 3-initiated atmospheric oxidation of vanillin and vanillic acid. CHEMOSPHERE 2022; 288:132544. [PMID: 34648789 DOI: 10.1016/j.chemosphere.2021.132544] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Revised: 09/30/2021] [Accepted: 10/10/2021] [Indexed: 06/13/2023]
Abstract
Vanillin and vanillic acid are two kinds of lignin pyrolysis products that are generated by biomass combustion. The gas-phase oxidation mechanisms of vanillin and vanillic acid initiated by OH/NO3 radicals were investigated by using density functional theory (DFT) at M06-2X/6-311+G(3df,2p)//M06-2X/6-311+G(d,p) level. The initial reactions of vanillin and vanillic acid with OH/NO3 radicals can be divided into two patterns: OH/NO3 addition and H-atom abstraction. For vanillin reacted with OH radical, the OH addition mainly occurs at C2-position to produce highly chemically activated intermediate (IM2). The oxidation products 3,4-dihydroxy benzaldehyde, malealdehyde, methyl hydrogen oxalate, methylenemalonaldehyde, carbonyl and carbonyl compounds are formed by the subsequent reactions of IM2. H-atom abstracting from aldehyde group occurs more easily than from the other positions. In addition, vanillin reacting with NO3 radicals principally proceeds via NO3-addition at C1 sites and H-atom abstracting from OH group (C1) to generate HNO3. The primary reaction mechanisms of vanillic acid with OH/NO3 radicals were similar to vanillin. The Rice-Ramsperger-Kassel-Marcus (RRKM) theory was performed to calculate the rate constants of the significant elementary reactions. The total rate constants for OH-initiated oxidation of vanillin and vanillic acid are 5.72 × 10-12 and 5.40 × 10-12 cm3 molecule-1 s-1 at 298 K and 1 atm. The atmospheric lifetimes were predicted to be 48.56 h and 51.44 h, respectively. As a supplement, the kinetic calculations of NO3 radicals with two reactants were also discussed. This work investigates the atmospheric oxidation processes of vanillin and vanillic acid, and hopes to provide useful information for further experimental research.
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Affiliation(s)
- Yanhui Sun
- College of Environment and Safety Engineering, Qingdao University of Science and Technology, Qingdao, 266042, PR China.
| | - Lin Liu
- College of Environment and Safety Engineering, Qingdao University of Science and Technology, Qingdao, 266042, PR China
| | - Ming Li
- College of Environment and Safety Engineering, Qingdao University of Science and Technology, Qingdao, 266042, PR China
| | - Xiaoxiao Chen
- College of Environment and Safety Engineering, Qingdao University of Science and Technology, Qingdao, 266042, PR China
| | - Fei Xu
- Environment Research Institute, Shandong University, Qingdao, 266237, PR China
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