Atmospheric chemical reaction mechanism and kinetics of 1,2-bis(2,4,6-tribromophenoxy)ethane initiated by OH radical: a computational study

Qi, Yu; Xie, Hong-Bin; Li, Tianchi; Ma, Fangfang; Fu, Zihao; Wang, Zhongyu; Li, Chao; Fu, Zhiqiang; Xia, Dao-Cheng; Chen, Jingwen

doi:10.1039/c6ra26700a

Cited by 15 publications

(15 citation statements)

References 55 publications

(74 reference statements)

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“…Reactants and transition states may have multiple conformers. Previous studies found that the involvement of multiconformers can more precisely predict the reaction kinetics, compared to single-conformer approximation. ,,,− A so-called single-conformer approximation implies that only one conformer for reactant and transition state was used in studying reaction mechanism and kinetics. − ,,,,,− ,− Here, multiconformer approximation was considered in the crucial reaction steps. The crucial reaction steps are determined by a kinetics analysis based on single-conformer approximation (details in the SI).…”

Section: Introductionmentioning

confidence: 99%

Atmospheric Chemistry of Allylic Radicals from Isoprene: A Successive Cyclization-Driven Autoxidation Mechanism

Guo

Xia

et al. 2021

Environ. Sci. Technol.

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The atmospheric chemistry of isoprene has broad implications for regional air quality and the global climate. Allylic radicals, taking 13−17% yield in the isoprene oxidation by • Cl, can contribute as much as 3.6−4.9% to all possible formed intermediates in local regions at daytime. Considering the large quantity of isoprene emission, the chemistry of the allylic radicals is therefore highly desirable. Here, we investigated the atmospheric oxidation mechanism of the allylic radicals using quantum chemical calculations and kinetics modeling. The results indicate that the allylic radicals can barrierlessly combine with O 2 to form peroxy radicals (RO 2• ). Under ≤100 ppt NO and ≤50 ppt HO 2• conditions, the formed RO 2 • mainly undergo two times "successive cyclization and O 2 addition" to finally form the product fragments 2-alkoxy-acetaldehyde (C 2 H 3 O 2• ) and 3-hydroperoxy-2-oxopropanal (C 3 H 4 O 4 ). The presented reaction illustrates a novel successive cyclization-driven autoxidation mechanism. The formed 3-hydroperoxy-2-oxopropanal product is a new isomer of the atmospheric C 3 H 4 O 4 family and a potential aqueous-phase secondary organic aerosol precursor. Under >100 ppt NO condition, NO can mediate the cyclization-driven autoxidation process to form C 5 H 7 NO 3 , C 5 H 7 NO 7 , and alkoxy radical-related products. The proposed novel autoxidation mechanism advances our current understanding of the atmospheric chemistry of both isoprene and RO 2• .

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Section: Introductionmentioning

confidence: 99%

Atmospheric Chemistry of Allylic Radicals from Isoprene: A Successive Cyclization-Driven Autoxidation Mechanism

Guo

Xia

et al. 2021

Environ. Sci. Technol.

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“…Density functional theory (DFT) methods represent a viable alternative for elucidating the kinetics and mechanisms of atmospheric chemistry processes, due to their excellent performance‐to‐cost ratio . Thus far, many functionals have been developed, each with merits and drawbacks.…”

Section: Introductionmentioning

confidence: 99%

“…• OH addition reactions play a pivotal role in the atmospheric transformation of a number of phenyl and substituted phenyl‐based persistent and toxic organic pollutants, such as polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), and polybrominated diphenyl ethers (PBDEs) . Consequently, the mechanisms and rate constants ( k OH ) of atmospheric • OH addition reactions are of great significance to determining their environmental risk.…”

Section: Introductionmentioning

confidence: 99%

“…Quantum chemical methods have been proven to be an effective tool for obtaining mechanistic information and k OH values via calculating thermodynamic parameters along reaction pathways and the reaction activation free energy (Δ G ‡ ) of various pathways . Generally, reliable computation of the thermodynamic parameters along reaction pathways and Δ G ‡ values requires high‐level treatment of the electron correlation by methods such as coupled cluster theory with singles and doubles including perturbative triples CCSD(T) .…”

Section: Introductionmentioning

confidence: 99%

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Benchmarking of DFT functionals for the kinetics and mechanisms of atmospheric addition reactions of OH radicals with phenyl and substituted phenyl‐based organic pollutants

Xie

Chen

2017

Int J of Quantum Chemistry

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•OH addition reactions play a pivotal role in the atmospheric transformation of a number of phenyl and substituted phenyl‐based persistent and toxic organic pollutants. Here, we screened appropriate DFT functionals to predict reaction mechanisms and rate constants (kOH) of the •OH additions by taking benzene and substituted benzenes (C6H5F, C6H5Cl, C6H5Br, C6H5CH3, C6H5OH) as model compounds. By comparing the kOH values calculated with DFT methods to experimental values, we found that the ωB97 functional is the best among the 18 functionals considered (using the basis sets 6‐31 + G(d,p) for optimizations and 6‐311++G(3df,2pd) for single point energy calculations) in the temperature range of 230‐330 K. In addition, we found that some other functionals performed well in specific conditions, e.g., BMKD3 is good for benzene, halogenated benzenes and C6H5CH3, and CAM‐B3LYP is good for the reaction of C6H5OH at room temperature. Based on the diversity of the electronic structures of the selected model compounds and the frequent occurrence of certain substituents (CH3, OH, F, Cl, and Br) in the target compounds, the functionals recommended here can be used for future study of the reaction mechanisms and kOH values for •OH addition to phenyl and substituted phenyl‐based persistent and toxic organic pollutants.

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“…39 Previous studies had revealed that the estimated OH values of some compounds by AOPWIN beyond its domain were significantly lower than the calculated values quantum chemical methods. 11,40 This suggested that the potential risk of LCMs in atmosphere might be underestimated. Therefore, in order to accurately assess the fate and transport of LCMs in the atmosphere, it is better to investigate their transformation kinetics rather than using the AOPWIN modeled gaseous kinetics.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Atmospheric Fate and Risk Investigation of Typical Liquid Crystal Monomers

Huang

Zhang

et al. 2021

ACS Sustainable Chem. Eng.

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Liquid crystal monomers (LCMs), widely used in liquid crystal displays, have been recognized as a class of potential emerging pollutants in the environment. However, their atmospheric fate and toxicity involved in the atmospheric transformation have been rarely investigated. Herein, we employed quantum chemical calculation and computational toxicology to systematically investigate the • OH-initiated oxidation kinetics and mechanism of three LCMs (4-cyanophenyl 4-ethylbenzoate (CEB), 4-cyano-3-fluorophenyl 4-ethylbenzoate (CEB-F), and 4cyano-3,5-difluorophenyl 4-ethylbenzoate (CEB-2F)) in the atmosphere, and the toxicity of CEB-2F (as an example) during transformation. The calculated gaseous rate constants and half-lives for CEB, CEB-F, and CEB-2F at 298 K were in the range of (0.9−1.4) × 10 −12 cm 3 molecule −1 s −1 and 5.7−8.9 days, respectively, suggesting that these LCMs had atmospheric persistence and long-range transport potential. The transformation products (TPs) of CEB-2F were found to be similar to those experimentally determined in • OH oxidation of particulate LCMs. Furthermore, some TPs were predicted to exhibit enhanced toxicity compared with the parent LCM, indicating that much attention should be also paid to their risks besides the original LCMs. These results would be helpful for the LCM regulation and provide guidance on their development and safe application.

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Atmospheric chemical reaction mechanism and kinetics of 1,2-bis(2,4,6-tribromophenoxy)ethane initiated by OH radical: a computational study

Abstract: The mechanism and kinetics of OH-initiated oxidation of BTBPE, an alternative of PBDEs, were investigated.

Cited by 15 publications

References 55 publications

Atmospheric Chemistry of Allylic Radicals from Isoprene: A Successive Cyclization-Driven Autoxidation Mechanism

Atmospheric Chemistry of Allylic Radicals from Isoprene: A Successive Cyclization-Driven Autoxidation Mechanism

Benchmarking of DFT functionals for the kinetics and mechanisms of atmospheric addition reactions of OH radicals with phenyl and substituted phenyl‐based organic pollutants

Atmospheric Fate and Risk Investigation of Typical Liquid Crystal Monomers

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