A quantum theory investigation on atmospheric oxidation mechanisms of acrylic acid by OH radical and its implication for atmospheric chemistry

2018 ◽  
Vol 25 (25) ◽  
pp. 24939-24950 ◽  
Author(s):  
Han Chu ◽  
Wenzhong Wu ◽  
Youxiang Shao ◽  
Yizhen Tang ◽  
Yunju Zhang ◽  
...  
Keyword(s):  
Quantum Theory ◽  
Acrylic Acid ◽  
Atmospheric Chemistry ◽  
Atmospheric Oxidation ◽  
Oh Radical ◽  
Oxidation Mechanisms

Atmospheric oxidation of fluoroalcohols initiated by ·OH radical in the presence of water and mineral dusts: Mechanism, kinetics, and risk assessment

2021 ◽  
Author(s):  
Feng-Yang Bai ◽  
Ming-Shuai Deng ◽  
Mei-Yan Chen ◽  
Lian Kong ◽  
Shuang Ni ◽  
...  
Keyword(s):  
Risk Assessment ◽  
Environmental Risks ◽  
Atmospheric Oxidation ◽  
Oh Radical ◽  
Mineral Dusts

The transport and formation of fluorinated compounds are greatly significant due to their possible environmental risks. In this work, the ·OH-mediated degradation of CF3CF2CF2CH2OH and CF3CHFCF2CH2OH in the existence of...

scholarly journals Theoretical Insights into the Electron Capture Behavior of H2SO4···N2O Complex: A DFT and Molecular Dynamics Study

Molecules ◽  
2018 ◽  
Vol 23 (9) ◽  
pp. 2349 ◽  
Author(s):  
Wei-Hua Wang ◽  
Wen-Ling Feng ◽  
Wen-Liang Wang ◽  
Ping Li
Keyword(s):  
Molecular Dynamics ◽  
Electron Capture ◽  
Atmospheric Chemistry ◽  
Density Functional ◽  
Molecular Complexes ◽  
Dft Method ◽  
Dynamics Simulation ◽  
Oh Radical ◽  
Before And After ◽  
Reduced Density

Both sulfuric acid (H2SO4) and nitrous oxide (N2O) play a central role in the atmospheric chemistry in regulating the global environment and climate changes. In this study, the interaction behavior between H2SO4 and N2O before and after electron capture has been explored using the density functional theory (DFT) method as well as molecular dynamics simulation. The intermolecular interactions have been characterized by atoms in molecules (AIM), natural bond orbital (NBO), and reduced density gradient (RDG) analyses, respectively. It was found that H2SO4 and N2O can form two transient molecular complexes via intermolecular H-bonds within a certain timescale. However, two molecular complexes can be transformed into OH radical, N2, and HSO4− species upon electron capture, providing an alternative formation source of OH radical in the atmosphere. Expectedly, the present findings not only can provide new insights into the transformation behavior of H2SO4 and N2O, but also can enable us to better understand the potential role of the free electron in driving the proceeding of the relevant reactions in the atmosphere.

Theoretical investigation on atmospheric oxidation of fluorene initiated by OH radical

2019 ◽  
Vol 669 ◽  
pp. 920-929 ◽  
Author(s):  
Zhezheng Ding ◽  
Yayi Yi ◽  
Qingzhu Zhang ◽  
Tao Zhuang
Keyword(s):  
Theoretical Investigation ◽  
Atmospheric Oxidation ◽  
Oh Radical

In situ measurement for tropospheric OH radical by Laser Induced Fluorescence technique during STORM campaign

2020 ◽  
Author(s):  
Fengyang Wang ◽  
Renzhi Hu ◽  
Pinhua Xie ◽  
Yihui Wang ◽  
Shengrong Lou ◽  
...  
Keyword(s):  
Atmospheric Chemistry ◽  
Photon Counting ◽  
Ambient Air ◽  
Laser Induced Fluorescence ◽  
Detection Sensitivity ◽  
Oh Radical ◽  
Fluorescence Technique ◽  
Radical Concentration ◽  
Mobile Observation

<p>Hydroxyl (OH) play an essential role in atmospheric chemistry. OH radical is an indicator of atmospheric oxidation and self-purification, which determines the removal of most trace gases in the atmosphere, such as CO, SO<sub>2</sub>, NO<sub>2</sub>, CH<sub>4</sub> and other volatile organic compounds (VOCs). A ground-based system for measurement of tropospheric OH radical by Laser Induced Fluorescence technique (AIOFM-LIF) was developed and integrated into a mobile observation platform for field observation. Ambient air expands through a 0.4 mm nozzle to low pressure. OH radical is irradiated by the 308 nm laser pulse at a repetition rate of 8.5 kHz, accompanying the release fluorescence of the A<sup>2</sup>Σ<sup>+</sup>(v’=0)—X<sup>2</sup>Π<sub>i</sub>(v’’=0) transition at 308 nm with the resultant fluorescence being detected by gated photon counting. The detection sensitivity of AIOFM-LIF system was calibrated by a portable standard OH radical source based on water photolysis-ozone actinometry. Following laboratory and field calibrations to characterise the instrument sensitivity, OH radical detection limits were (1.84±0.26) × 10<sup>5</sup> cm<sup>-3</sup> and (3.69±0.52) × 10<sup>5</sup> cm<sup>-3</sup> at night and noon, respectively. During “A comprehensive STudy of the Ozone foRmation Mechanism in Shenzhen” (STORM) campaign, AIOFM-LIF system was deployed in Shenzhen, China, and OH radical concentration was obtained validly except for the rainy days. Mean diurnal variation of HOx radical concentration was obtained, and the peak was 6.6×10<sup>6</sup> cm<sup>-3</sup> which appeared around 12:00 at noon. A general good agreement of OH radical concentration with j(O<sup>1</sup>D) was observed with a high correlation (R<sup>2</sup> =0.77), which illustrates that photolysis of ozone is an important source of OH radical during this campaign. A box model was applied to simulate the concentrations of OH at this field site, the primary production of OH radical was generally dominated by photolysis of O<sub>3</sub>, HONO, HCHO, while the other production was contributed by calculated species (OVOCs).</p>

Atmospheric chemistry of CF3CFCH2: Products and mechanisms of Cl atom and OH radical initiated oxidation

2008 ◽  
Vol 450 (4-6) ◽  
pp. 263-267 ◽  
Author(s):  
M.D. Hurley ◽  
T.J. Wallington ◽  
M.S. Javadi ◽  
O.J. Nielsen
Keyword(s):  
Atmospheric Chemistry ◽  
Oh Radical ◽  
Cl Atom

Atmospheric oxidation mechanism of polyfluorinated sulfonamides — A quantum chemical and kinetic study

2013 ◽  
Vol 91 (6) ◽  
pp. 472-478 ◽  
Author(s):  
Xiaoyan Sun ◽  
Lei Ding ◽  
Qingzhu Zhang ◽  
Wenxing Wang
Keyword(s):  
Rate Constants ◽  
Density Functional ◽  
Single Point ◽  
Oxidation Mechanism ◽  
Basis Set ◽  
Atmospheric Oxidation ◽  
Oh Radicals ◽  
Oh Radical ◽  
Orbital Theory ◽  
Point Energy

Polyfluorinated sulfonamides (FSAs, F(CF2)nSO2NR1R2) are present in the atmosphere and may serve as the source of perfluorocarboxylates (PFCAs, CF3(CF2)nCOO–) in remote locations through long-range atmospheric transport and oxidation. Density functional theory (DFT) molecular orbital theory calculations were carried out to investigate OH radical-initiated atmospheric oxidation of a series of sulfonamides, F(CF2)nSO2NR1R2 (n = 4, 6, 8). Geometry optimizations of the reactants as well as the intermediates, transition states, and products were performed at the MPWB1K level with the 6-31G+(d,p) basis set. Single-point energy calculations were carried out at the MPWB1K/6-311+G(3df,2p) level of theory. The OH radical-initiated reaction mechanism is given and confirms that the OH addition to the sulfone double bond producing perfluoroalkanesulfonic acid directly cannot occur in the general atmosphere. Canonical variational transition-state (CVT) theory with small curvature tunneling (SCT) contribution was used to predict the rate constants. The overall rate constants were determined, k(T) (N-EtFBSA + OH) = (3.21 × 10−12) exp(–584.19/T), k(T) (N-EtFHxSA + OH) = (3.21 × 10−12) exp(–543.24/T), and k(T) (N-EtFOSA + OH) = (2.17 × 10−12) exp(–504.96/T) cm3 molecule−1 s−1, over the possible atmospheric temperature range of 180–370 K, indicating that the length of the F(CF2)n group has no large effect on the reactivity of FSAs. Results show that the atmospheric lifetime of FSAs determined by OH radicals will be 20–40 days, which agrees well with the experimental values (20–50 days), 20 thus they may contribute to the burden of perfluorinated pollution in remote regions.

Atmospheric Chemistry of Perfluorinated Aldehyde Hydrates (n-CxF2x+1CH(OH)2,x= 1, 3, 4):  Hydration, Dehydration, and Kinetics and Mechanism of Cl Atom and OH Radical Initiated Oxidation

2006 ◽  
Vol 110 (32) ◽  
pp. 9854-9860 ◽  
Author(s):  
M. P. Sulbaek Andersen ◽  
A. Toft ◽  
O. J. Nielsen ◽  
M. D. Hurley ◽  
T. J. Wallington ◽  
...  
Keyword(s):  
Atmospheric Chemistry ◽  
Kinetics And Mechanism ◽  
Oh Radical ◽  
Cl Atom

scholarly journals Atmospheric chemistry of trans-CF<sub>3</sub>CH=CHF: products and mechanisms of hydroxyl radical and chlorine atom initiated oxidation

2008 ◽  
Vol 8 (1) ◽  
pp. 1069-1088
Author(s):  
M. S. Javadi ◽  
R. Søndergaard ◽  
O. J. Nielsen ◽  
M. D. Hurley ◽  
T. J. Wallington
Keyword(s):  
Environmental Impact ◽  
Hydroxyl Radical ◽  
Partial Pressure ◽  
Chlorine Atom ◽  
Atmospheric Chemistry ◽  
Oh Radical ◽  
Smog Chamber ◽  
O2 Partial Pressure ◽  
Cl Atom

Abstract. Smog chamber/FTIR techniques were used to study the products and mechanisms of OH radical and Cl atom initiated oxidation of trans-CF3CH=CHF in 700 Torr of N2/O2 diluent at 295±1 K. Hydroxyl radical initiated oxidation leads to the formation of CF3CHO and HC(O)F in yields which were indistinguishable from 100% and were not dependent on the O2 partial pressure. Chlorine atom initiated oxidation gives HC(O)F, CF3CHO, CF3C(O)Cl, and CF3C(O)CHFCl. The yields of CF3C(O)Cl and CF3C(O)CHFCl increased at the expense of HC(O)F and CF3CHO as the O2 partial pressure was increased over the range 5–700 Torr. The results are discussed with respect to the atmospheric chemistry and environmental impact of trans-CF3CH=CHF.

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