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Quintano MM, Rodrigues GLS, Chagas MA, Rocha WR. Revisiting the Tropospheric OH-Initiated Unimolecular Decomposition of Chlorpyrifos and Chlorpyrifos-Methyl: A Theoretical Perspective. J Phys Chem A 2020; 124:4280-4289. [PMID: 32374604 DOI: 10.1021/acs.jpca.0c02006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Based on density functional theory (DFT) electronic structure calculations with dispersion correction, we propose new reaction pathways in which no extra reaction step is necessary to account for the formation of 3,5,6-trichloro-2-pyridynol (TCP) within the process of tropospheric OH-initiated unimolecular decomposition of chlorpyrifos (CLP) and chlorpyrifos-methyl (CLPM). Chlorpyrifos and its analogous compound are among the most used organophosphorus pesticides worldwide, and their unimolecular decomposition in the troposphere is a dominant process of removal in the gas phase. The reaction pathways that we put forward have turned out to be the most exergonic ones among the three possible routes for the attack of the hydroxyl radical to the thiophosphoryl (P═S) bond of both CLP and CLPM. The results showed that the reaction is thermodynamically controlled with the formation of P-bonded adducts via a six-membered ring. The unimolecular decomposition of such reactive intermediates takes place with small energy barriers (less than 3 kcal mol-1) and is distinguished by hydrogen transfer to the nitrogen atom of the aromatic ring, resulting in the formation of 3,5,6-trichloro-2-pyridinol (TCP) and dialkyl phosphate radical (DAP·) product complexes in a single step.
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Affiliation(s)
- Mateus M Quintano
- Laboratory of Computational Studies on Molecular Systems, eCsMolab Department of Chemistry, ICEx, Federal University of Minas Gerais Pampulha, Belo Horizonte 31270-901, MG, Brazil
| | - Gabriel L S Rodrigues
- Laboratory of Computational Studies on Molecular Systems, eCsMolab Department of Chemistry, ICEx, Federal University of Minas Gerais Pampulha, Belo Horizonte 31270-901, MG, Brazil
| | - Marcelo A Chagas
- Laboratory of Computational Studies on Molecular Systems, eCsMolab Department of Chemistry, ICEx, Federal University of Minas Gerais Pampulha, Belo Horizonte 31270-901, MG, Brazil
| | - Willian R Rocha
- Laboratory of Computational Studies on Molecular Systems, eCsMolab Department of Chemistry, ICEx, Federal University of Minas Gerais Pampulha, Belo Horizonte 31270-901, MG, Brazil
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Saheb V. The mechanism and kinetics of the gas-phase reactions of OH radicals with O,O-diethyl methylphosphonothioate, (C2H5O)2P(S)CH3: Theoretical investigations. COMPUT THEOR CHEM 2019. [DOI: 10.1016/j.comptc.2019.05.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Clark KK, Mezyk SP, Abbott A, Kiddle JJ. Kinetic studies of the AOP radical-based oxidative and reductive destruction of pesticides and model compounds in water. CHEMOSPHERE 2018; 197:193-199. [PMID: 29351878 DOI: 10.1016/j.chemosphere.2017.12.190] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2017] [Revised: 12/26/2017] [Accepted: 12/30/2017] [Indexed: 06/07/2023]
Abstract
Absolute second-order rate constants for hydroxyl radical (HO) reaction with four organophosphorus pesticides, malathion, parathion, fenthion and ethion, and a suite of model compounds of structure (EtO)2P(S)-X (where X = Cl, F, SH, SEt, OCH2CF3, OEt, NH2, and CH3) were measured using electron pulse radiolysis and transient absorption techniques. Specific values were determined for these four pesticides as k = (3.89 ± 0.28) x 109, (2.20 ± 0.15) x 109, (2.02 ± 0.15) x 109 and (2.93 ± 0.10) x 109 M-1 s-1, respectively, at 20 ± 2 °C. The corresponding Brönsted plot for all these compounds demonstrated that the HO oxidation reaction mechanism for the pesticides was consistent with the model compounds, attributed to initial HO-adduct formation at the P(S) moiety. For malathion, steady-state 60Co radiolysis and 31P NMR analyses showed that hydroxyl radical-induced oxidation produces the far more potent isomalathion, but only with an efficiency of 4.9 ± 0.3%. Analogous kinetic measurements for the hydrated electron induced reduction of these pesticides gave specific rate constants of k = (3.38 ± 0.14) x 109, (1.38 ± 0.10) x 109, (1.19 ± 0.12) x 109 and (1.20 ± 0.06) x 109 M-1 s-1, respectively, for malathion, parathion, fenthion and ethion. Model compound measurements again supported a single reduction reaction mechanism, proposed to be electron addition at the PS bond to form the radical anion. These results demonstrate, for the first time, that the radical-based treatment of organophosphorus contaminated waters may present a potential toxicological risk if advanced oxidative processes are used.
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Affiliation(s)
- Kristin K Clark
- Department of Chemistry and Biochemistry, California State University at Long Beach, 1250 Bellflower Blvd., Long Beach, CA 90840, USA
| | - Stephen P Mezyk
- Department of Chemistry and Biochemistry, California State University at Long Beach, 1250 Bellflower Blvd., Long Beach, CA 90840, USA.
| | - Amberashley Abbott
- Department of Chemistry, Western Michigan University, 3425 Wood Hall, Kalamazoo, MI 49008, USA
| | - James J Kiddle
- Department of Chemistry, Western Michigan University, 3425 Wood Hall, Kalamazoo, MI 49008, USA.
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Liu C, Yang B, Zeng C. Kinetic studies of heterogeneous reactions of particulate phosmet and parathion with NO3 radicals. CHEMOSPHERE 2015; 119:1276-1280. [PMID: 25460772 DOI: 10.1016/j.chemosphere.2014.09.049] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2014] [Revised: 09/10/2014] [Accepted: 09/15/2014] [Indexed: 06/04/2023]
Abstract
Organophosphorous pesticides (OPPs) are ubiquitous pollutants in the atmospheric environment with adverse effects on human health. In this study, heterogeneous kinetics of particulate phosmet and parathion with NO3 radicals were investigated with a mixed-phase relative rate method. A vacuum ultraviolet photoionization aerosol time-of-flight mass spectrometer (VUV-ATOFMS) and an atmospheric gas analysis mass spectrometer were used to monitor online the decays of particulate OPPs and reference compound, respectively. Reactive uptake coefficients of NO3 radicals on phosmet and parathion particles were (0.12±0.03) and (0.14±0.04), respectively, calculated according to the measured OPPs loss ratios and the average NO3 concentrations. Additionally, the average effective rate constants for heterogeneous reactions of particulate phosmet and parathion with NO3 radicals measured under experimental conditions were (2.80±0.16)×10(-12) and (2.97±0.13)×10(-12) cm(3) molecule(-1) s(-1), respectively. The experimental results of these heterogeneous reactions in the aerosol state provide supplementary knowledge for kinetic behaviors of airborne OPPs particles.
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Affiliation(s)
- Changgeng Liu
- School of Resources and Environmental Engineering, Panzhihua University, Panzhihua 617000, China; Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
| | - Bo Yang
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Chenghua Zeng
- School of Resources and Environmental Engineering, Panzhihua University, Panzhihua 617000, China
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Muñoz A, Ródenas M, Borrás E, Vázquez M, Vera T. The gas-phase degradation of chlorpyrifos and chlorpyrifos-oxon towards OH radical under atmospheric conditions. CHEMOSPHERE 2014; 111:522-528. [PMID: 24997961 DOI: 10.1016/j.chemosphere.2014.04.087] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2013] [Revised: 04/24/2014] [Accepted: 04/27/2014] [Indexed: 06/03/2023]
Abstract
The OH initiated oxidation of chlorpyrifos (a widely used insecticide) and its photooxidation product chlorpyrifos-oxon were investigated at the large outdoor European Photoreactor (EUPHORE). The rate constants for reaction of chlorpyrifos and chlorpyrifos oxon with OH radicals were measured using a conventional relative rate method. The value of the OH reaction rate constants with chlorpyrifos and chlorpyrifos-oxon were determined to be k=(9.1±2.1)×10(-11)cm(3)molecule(-1)s(-1) and (1.7±0.9)×10(-11)cm(3)molecule(-1)s(-1) at 303±5K and atmospheric pressure. They gave an atmospheric lifetime in relation to the reaction with OH of approximately 2h and 11h for chlorpyrifos and chlorpyrifos-oxon, respectively. Photolysis was found to be unimportant relative to reaction with OH. The main products detected in the gas phase from the reaction of OH with chlorpyrifos were SO2, chlorpyrifos-oxon, 3,5,6-trichloro-2-pyridinol and diethylphosphate with molar yields of 17±5%, ∼10%, 8±4% and 30±9%, respectively.
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Affiliation(s)
- Amalia Muñoz
- EUPHORE, Instituto Universitario UMH-CEAM, C/Charles R. Darwin, 14, Parque Tecnológico, 46980 Paterna, Valencia, Spain.
| | - Milagros Ródenas
- EUPHORE, Instituto Universitario UMH-CEAM, C/Charles R. Darwin, 14, Parque Tecnológico, 46980 Paterna, Valencia, Spain
| | - Esther Borrás
- EUPHORE, Instituto Universitario UMH-CEAM, C/Charles R. Darwin, 14, Parque Tecnológico, 46980 Paterna, Valencia, Spain
| | - Mónica Vázquez
- EUPHORE, Instituto Universitario UMH-CEAM, C/Charles R. Darwin, 14, Parque Tecnológico, 46980 Paterna, Valencia, Spain
| | - Teresa Vera
- EUPHORE, Instituto Universitario UMH-CEAM, C/Charles R. Darwin, 14, Parque Tecnológico, 46980 Paterna, Valencia, Spain
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Aschmann SM, Atkinson R. Atmospheric chemistry of methyl and ethyl N,N,N',N'-tetramethylphosphorodiamidate and O,S-dimethyl methylphosphonothioate. J Phys Chem A 2013; 117:11038-48. [PMID: 24134801 DOI: 10.1021/jp407702w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Rate constants for the reactions of OH radicals with methyl N,N,N',N'-tetramethylphosphorodiamidate [CH3OP(O)[N(CH3)2]2; MTMPDA], ethyl N,N,N',N'-tetramethylphosphorodiamidate [C2H5OP(O)[N(CH3)2]2; ETMPDA], and O,S-dimethyl methylphosphonothioate [CH3OP(O)(CH3)SCH3; OSDMMP] have been measured over the temperature range 281-349 K at atmospheric pressure of air using a relative rate method. The rate expressions obtained were 4.96 × 10(-12) e((1058±71)/T) cm(3) molecule(-1) s(-1) (1.73 × 10(-10) cm(3) molecule(-1) s(-1) at 298 K) for OH + MTMPDA, 4.46 × 10(-12) e((1144±95)/T) cm(3) molecule(-1) s(-1) (2.07 × 10(-10) cm(3) molecule(-1) s(-1) at 298 K) for OH + ETMPDA, and 1.31 × 10(-13) e((1370±229)/T) cm(3) molecule(-1) s(-1) (1.30 × 10(-11) cm(3) molecule(-1) s(-1) at 298 K) for OH + OSDMMP. The rate constant for OH + OSDMMP was independent of O2 content over the range 2.1-71% O2 at 296 ± 2 K. In addition, rate constants for the reactions of NO3 radicals and O3 with MTMPDA, of (1.4 ± 0.1) × 10(-12) cm(3) molecule(-1) s(-1) and <3.5 × 10(-19) cm(3) molecule(-1) s(-1), respectively, were measured at 297 ± 2 K. Products of the OH radical- and, for MTMPDA, NO3 radical-initiated reactions were investigated using gas chromatography and in situ atmospheric pressure ionization mass spectrometry. A product of molecular weight 180 was observed from the OH and NO3 radical-initiated reactions of MTMPDA, and this is attributed to CH3OP(O)[N(CH3)2]N(CH3)CHO. Similarly, a product of molecular weight 194 was observed from the OH + ETMPDA reaction and attributed to C2H5OP(O)[N(CH3)2]N(CH3)CHO. Possible reaction mechanisms are discussed.
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Affiliation(s)
- Sara M Aschmann
- Air Pollution Research Center, University of California , Riverside, California 92521, United States
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Wang Y, Yang B, Zhang P, Zhang W, Liu C, Shu X, Shu J. Heterogeneous reactions of pirimiphos-methyl and pirimicarb with NO3 radicals. J Phys Chem A 2012; 116:10802-9. [PMID: 23083006 DOI: 10.1021/jp3071635] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Pirimiphos-methyl (PMM) and pirimicarb (PM) are two typical N,N-dialkyl substituted pyrimidine pesticides. The heterogeneous reactions of suspended PMM and PM particles with NO(3) radicals are investigated using an online aerosol time-of-flight mass spectrometer and a real-time atmospheric gas analysis mass spectrometer. Three products for PMM and five products for PM are observed and assigned with the aid of GC/MS. Phosphoric acid 2-diethylamino-6-methyl-4-pyrimidinyl dimethyl ester and 2-(dimethylamino)-5,6-dimethyl-4-hydroxy-pyrimidine are the main reaction products observed for PMM and PM, respectively. The effective rate constants for the reactions of PMM and PM particles with NO(3) radicals are (9.9 ± 0.3) × 10(-12) and (7.5 ± 0.3) × 10(-13) cm(3) molecule(-1) s(-1), respectively, obtained using a mixed-phase relative rate method. Geometries and energies of transition states (TS) and intermediates (IM) are obtained by DFT calculation to elucidate the detailed mechanism of the P═S group oxidation into the P═O group for PMM. The theoretical studies present the reasonable intermediates including the S-oxide and the diradical (IM1(a) and IM2(a)). The mechanism explanation may provide useful information for understanding the degradation mechanism of organothionophosphorus compounds in the environment.
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Affiliation(s)
- Youfeng Wang
- Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
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Sandhiya L, Kolandaivel P, Senthilkumar K. Reaction mechanism and kinetics of the atmospheric oxidation of 1,4-thioxane by NO3 — A theoretical study. CAN J CHEM 2012. [DOI: 10.1139/v2012-010] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Volatile organic compounds (VOCs) are emitted as pollutants into the atmosphere from many natural and artificial sources. The oxidation of VOCs by atmospheric species plays a key role in the degradation of VOCs. In the present investigation, the atmospheric degradation of a cyclic organosulfur compound, 1,4-thioxane, by an NO3• radical is studied. Pathways for the reaction of 1,4-thioxane with the NO3• radical were modeled through electronic structure calculations using density functional theory methods B3LYP, M06-2X, and MP2 with the 6–31G(d,p) basis set. The NO3•-initiated reaction of 1,4-thioxane was found to proceed in three ways: by single-hydrogen atom abstraction, by direct transfer of the O atom of NO3• to the S atom moiety of 1,4-thioxane, or by two-hydrogen atom transfer reactions leading to the formation of a peroxy radical intermediate, which further undergoes secondary reactions with other atmospheric species. Structures, energies, and vibrational frequencies obtained from M06-2X/6–31G(d,p) electronic structure calculations were subsequently used to perform canonical variational transition-state theory calculations to determine the rate constants over the temperature range of 278–350 K and to study the lifetime of 1,4-thioxane in the atmosphere. The rate constant calculated for the reaction of 1,4-thioxane with the NO3• radical is in good agreement with the available experimental data.
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Affiliation(s)
- L. Sandhiya
- Department of Physics, Bharathiar University, Coimbatore - 641 046, India
| | - P. Kolandaivel
- Department of Physics, Bharathiar University, Coimbatore - 641 046, India
| | - K. Senthilkumar
- Department of Physics, Bharathiar University, Coimbatore - 641 046, India
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9
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Theoretical studies on the reaction mechanism and kinetics of the atmospheric reactions of 1,4-thioxane with OH radical. Struct Chem 2012. [DOI: 10.1007/s11224-012-9955-8] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Muñoz A, Person AL, Calvé SL, Mellouki A, Borrás E, Daële V, Vera T. Studies on atmospheric degradation of diazinon in the EUPHORE simulation chamber. CHEMOSPHERE 2011; 85:724-730. [PMID: 21733545 DOI: 10.1016/j.chemosphere.2011.06.044] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2011] [Revised: 06/03/2011] [Accepted: 06/07/2011] [Indexed: 05/31/2023]
Abstract
The gas phase atmospheric degradation of diazinon has been investigated at the large outdoor European Photoreactor (EUPHORE) in Valencia, Spain. The rate constant for reaction of diazinon with OH radicals was measured using a conventional relative rate method with di-n-buthylether as reference compound being k = (3.5 ± 1.2) × 10⁻¹¹ cm³ molecule⁻¹ s⁻¹ at 302 ± 10 K and atmospheric pressure. The available evidence indicates that tropospheric degradation of diazinon is mainly controlled by reaction with OH radicals, and that the tropospheric lifetime with respect to the OH reaction is estimated to be around 4h whereas its lifetime with respect to the photolysis is higher than 1d under our conditions. Significant aerosol formation was observed following the reaction of diazinon with OH radicals, and the main carbon-containing products detected in the particle phase were hydroxydiazinon, hydroxydiazoxon and 2-isopropyl-6-methyl-pyrimidinyl-4-ol.
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Affiliation(s)
- Amalia Muñoz
- Instituto Universitario CEAM-UMH, C/Charles R. Darwin 14, Parque Tecnológico, 46980 Paterna, Valencia, Spain.
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Aschmann SM, Tuazon EC, Long WD, Atkinson R. Atmospheric chemistry of dichlorvos. J Phys Chem A 2011; 115:2756-64. [PMID: 21405039 DOI: 10.1021/jp112019s] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Dichlorvos [2,2-dichlorovinyl dimethyl phosphate, (CH(3)O)(2)P(O)OCH═CCl(2)] is a relatively volatile in-use insecticide. Rate constants for its reaction with OH radicals have been measured over the temperature range 296-348 K and atmospheric pressure of air using a relative rate method. The rate expression obtained was 3.53 × 10(-13) e((1367±239)/T) cm(3) molecule(-1) s(-1), with a 298 K rate constant of (3.5 ± 0.7) × 10(-11) cm(3) molecule(-1) s(-1), where the error in the 298 K rate constant is the estimated overall uncertainty. In addition, rate constants for the reactions of NO(3) radicals and O(3) with dichlorvos, of (2.5 ± 0.5) × 10(-13) cm(3) molecule(-1) s(-1) and (1.7 ± 1.0) × 10(-19) cm(3) molecule(-1) s(-1), respectively, were measured at 296 ± 2 K. Products of the OH and NO(3) radical-initiated reactions were investigated using in situ atmospheric pressure ionization mass spectrometry (API-MS) and (OH radical reaction only) in situ Fourier transform infrared (FT-IR) spectroscopy. For the OH radical reaction, the major initial products were CO, phosgene [C(O)Cl(2)] and dimethyl phosphate [(CH(3)O)(2)P(O)OH], with equal (to within ±10%) formation yields of CO and C(O)Cl(2). The API-MS analyses were consistent with formation of (CH(3)O)(2)P(O)OH from both the OH and NO(3) radical-initiated reactions. In the atmosphere, the dominant chemical loss processes for dichlorvos will be daytime reaction with OH radicals and nighttime reaction with NO(3) radicals, with an estimated lifetime of a few hours.
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Affiliation(s)
- Sara M Aschmann
- Air Pollution Research Center, University of California, Riverside, California 92521, United States
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Aschmann SM, Tuazon EC, Long WD, Atkinson R. Atmospheric Chemistry of Isopropyl Methyl Methylphosphonate and Dimethyl N,N-Dimethylphosphoroamidate. J Phys Chem A 2010; 114:3523-32. [DOI: 10.1021/jp911668h] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Sara M. Aschmann
- Air Pollution Research Center, Department of Environmental Sciences, and Department of Chemistry, University of California, Riverside, California 92521
| | - Ernesto C. Tuazon
- Air Pollution Research Center, Department of Environmental Sciences, and Department of Chemistry, University of California, Riverside, California 92521
| | - William D. Long
- Air Pollution Research Center, Department of Environmental Sciences, and Department of Chemistry, University of California, Riverside, California 92521
| | - Roger Atkinson
- Air Pollution Research Center, Department of Environmental Sciences, and Department of Chemistry, University of California, Riverside, California 92521
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Aschmann SM, Long WD, Atkinson R. Kinetics of the Gas-Phase Reactions of OH and NO3 Radicals and O3 with 1,4-Thioxane and 1,4-Dithiane. J Phys Chem A 2008; 112:13556-65. [DOI: 10.1021/jp8074018] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- Sara M. Aschmann
- Air Pollution Research Center, Department of Environmental Sciences and Department of Chemistry, University of California, Riverside, California 92521
| | - William D. Long
- Air Pollution Research Center, Department of Environmental Sciences and Department of Chemistry, University of California, Riverside, California 92521
| | - Roger Atkinson
- Air Pollution Research Center, Department of Environmental Sciences and Department of Chemistry, University of California, Riverside, California 92521
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Aschmann SM, Tuazon EC, Long WD, Atkinson R. Kinetics and Products of the Gas-Phase Reactions of Divinyl Sulfoxide with OH and NO3 Radicals and O3. J Phys Chem A 2008; 112:8723-30. [DOI: 10.1021/jp803223e] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- Sara M. Aschmann
- Air Pollution Research Center, University of California, Riverside, California 92521
| | - Ernesto C. Tuazon
- Air Pollution Research Center, University of California, Riverside, California 92521
| | - William D. Long
- Air Pollution Research Center, University of California, Riverside, California 92521
| | - Roger Atkinson
- Air Pollution Research Center, University of California, Riverside, California 92521
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Aschmann SM, Long WD, Atkinson R. Rate Constants for the Gas-Phase Reactions of OH Radicals with Dimethyl Phosphonate over the Temperature Range of 278−351 K and for a Series of Other Organophosphorus Compounds at ∼280 K. J Phys Chem A 2008; 112:4793-9. [DOI: 10.1021/jp800899y] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Sara M. Aschmann
- Air Pollution Research Center, University of California, Riverside, California 92521
| | - William D. Long
- Air Pollution Research Center, University of California, Riverside, California 92521
| | - Roger Atkinson
- Air Pollution Research Center, University of California, Riverside, California 92521
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Tuazon EC, Aschmann SM, Atkinson R. Products of the Gas-Phase Reactions of OH Radicals with (C2H5O)2P(S)CH3 and (C2H5O)3PS. J Phys Chem A 2007; 111:916-24. [PMID: 17266233 DOI: 10.1021/jp067274e] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Products of the gas-phase reactions of OH radicals with O,O-diethyl methylphosphonothioate [(C2H5O)2P(S)CH3, DEMPT] and O,O,O-triethyl phosphorothioate [(C2H5O)3PS, TEPT] have been investigated at room temperature and atmospheric pressure of air using in situ atmospheric pressure ionization mass spectrometry (API-MS) and, for the TEPT reaction, gas chromatography and in situ Fourier transform infrared (FT-IR) spectroscopy. Combined with products quantified previously by gas chromatography, the products observed were: from the DEMPT reaction, (C2H5O)2P(O)CH3 (21+/-4% yield) and C2H5OP(S)(CH3)OH or C2H5OP(O)(CH3)SH (presumed to be C2H5OP(O)(CH3)SH by analogy with the TEPT reaction); and from the TEPT reaction, (C2H5O)3PO (54-62% yield), SO2 (67+/-10% yield), CH3CHO (22-40% yield) and, tentatively, (C2H5O)2P(O)SH. The FT-IR analyses showed that the formation yields of HCHO, CO, CO2, peroxyacetyl nitrate [CH3C(O)OONO2], organic nitrates, and acetates from the TEPT reaction were <5%, 3+/-1%, <7%, <2%, 5+/-3%, and 3+/-2%, respectively. Possible reaction mechanisms are discussed.
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Affiliation(s)
- Ernesto C Tuazon
- Air Pollution Research Center, University of California, Riverside, California 92521, USA
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