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Huynh HN, McNeill VF. Heterogeneous Chemistry of CaCO 3 Aerosols with HNO 3 and HCl. J Phys Chem A 2020; 124:3886-3895. [PMID: 32324406 DOI: 10.1021/acs.jpca.9b11691] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Calcite (CaCO3) aerosols often serve as an idealized proxy for calcium-rich mineral dust. Their use has also previously been proposed for stratospheric solar radiation management (SSRM). Little is known about the heterogeneous chemistry of calcite aerosols with trace gases HNO3 and HCl and therefore their potential impact on stratospheric ozone (O3). Here we report the results of an experimental study of the uptake of HNO3 and HCl onto submicron CaCO3 particles in two different flow reactors. Products and reaction kinetics were observed by impacting aerosolized CaCO3 onto ZnSe windows, exposing them to the reagent gases at a wide range of concentrations, at 296 K and under dry conditions, and analyzing the particles before and after trace gas exposure using Fourier transform infrared spectroscopy (FTIR). A Ca(OH)(HCO3) termination layer was detected in the form of a HCO3- peak in the FTIR spectra, indicating a hydrated surface even under dry conditions. The results demonstrate the reaction of HNO3 with Ca(OH)(HCO3) to produce Ca(NO3)2, water, and CO2. HCl reacted with Ca(OH)(HCO3) to produce CaCl2 and also water and CO2. The depletion of the Ca(OH)(HCO3)/Ca(CO3) signal due to reaction with HNO3 or HCl followed pseudo-first-order kinetics. From the FTIR analysis, the reactive uptake coefficient for HNO3 was determined to be in the range of 0.013 ≤ γHNO3 ≤ 0.14, and that for HCl was 0.0011 ≤ γHCl ≤ 0.012 within the reported uncertainty. The reaction of HCl with airborne CaCO3 aerosols was also studied in an aerosol flow tube coupled with a quadrupole chemical ionization mass spectrometer (CIMS) under similar conditions to the FTIR study, and γHCl was determined to be 0.013 ± 0.001. Following previous modeling studies, these results suggest that the reactions of HCl and HNO3 with calcite in the stratosphere could ameliorate the potential for stratospheric solar radiation management to lead to stratospheric ozone depletion.
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Affiliation(s)
- Han N Huynh
- Department of Chemical Engineering, Columbia University, New York, New York 10027, United States
| | - V Faye McNeill
- Department of Chemical Engineering, Columbia University, New York, New York 10027, United States
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2
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Pfrang C, Rastogi K, Cabrera-Martinez ER, Seddon AM, Dicko C, Labrador A, Plivelic TS, Cowieson N, Squires AM. Complex three-dimensional self-assembly in proxies for atmospheric aerosols. Nat Commun 2017; 8:1724. [PMID: 29170428 PMCID: PMC5701067 DOI: 10.1038/s41467-017-01918-1] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2017] [Accepted: 10/25/2017] [Indexed: 01/23/2023] Open
Abstract
Aerosols are significant to the Earth’s climate, with nearly all atmospheric aerosols containing organic compounds that often contain both hydrophilic and hydrophobic parts. However, the nature of how these compounds are arranged within an aerosol droplet remains unknown. Here we demonstrate that fatty acids in proxies for atmospheric aerosols self-assemble into highly ordered three-dimensional nanostructures that may have implications for environmentally important processes. Acoustically trapped droplets of oleic acid/sodium oleate mixtures in sodium chloride solution are analysed by simultaneous synchrotron small-angle X-ray scattering and Raman spectroscopy in a controlled gas-phase environment. We demonstrate that the droplets contained crystal-like lyotropic phases including hexagonal and cubic close-packed arrangements of spherical and cylindrical micelles, and stacks of bilayers, whose structures responded to atmospherically relevant humidity changes and chemical reactions. Further experiments show that self-assembly reduces the rate of the reaction of the fatty acid with ozone, and that lyotropic-phase formation also occurs in more complex mixtures more closely resembling compositions of atmospheric aerosols. We suggest that lyotropic-phase formation likely occurs in the atmosphere, with potential implications for radiative forcing, residence times and other aerosol characteristics. Nearly all atmospheric aerosols contain surface-active organic compounds; however, the nature of how they arrange remains poorly understood. Here, the authors show that fatty acids in atmospheric aerosol proxies self-assemble into highly ordered, viscous 3D nanostructures that undergo changes upon exposure to humidity and ozone.
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Affiliation(s)
- C Pfrang
- Department of Chemistry, University of Reading, Whiteknights Campus, PO Box 224, Reading, RG6 6AD, UK.
| | - K Rastogi
- Department of Chemistry, University of Reading, Whiteknights Campus, PO Box 224, Reading, RG6 6AD, UK
| | - E R Cabrera-Martinez
- Department of Chemistry, University of Reading, Whiteknights Campus, PO Box 224, Reading, RG6 6AD, UK
| | - A M Seddon
- H.H. Wills Physics Laboratory, University of Bristol, Tyndall Avenue, Bristol, BS8 1TL, UK.,Bristol Centre for Functional Nanomaterials, H.H. Wills Physics Laboratory, University of Bristol, Tyndall Avenue, Bristol, BS8 1TL, UK
| | - C Dicko
- Pure and Applied Biochemistry, Chemical Center, University of Lund, Naturvetarvägen 14, 22241, Lund, Sweden
| | - A Labrador
- MAX IV Laboratory, University of Lund, PO Box 188, 22100, Lund, Sweden
| | - T S Plivelic
- MAX IV Laboratory, University of Lund, PO Box 188, 22100, Lund, Sweden
| | - N Cowieson
- Diamond Light Source, Harwell Science & Innovation Campus, Didcot, OX11 0DE, UK
| | - A M Squires
- Department of Chemistry, University of Reading, Whiteknights Campus, PO Box 224, Reading, RG6 6AD, UK. .,Department of Chemistry, University of Bath, Claverton Down, Bath, BA2 7AY, UK.
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3
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Aregahegn KZ, Shemesh D, Gerber RB, Finlayson-Pitts BJ. Photochemistry of Thin Solid Films of the Neonicotinoid Imidacloprid on Surfaces. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2017; 51:2660-2668. [PMID: 27989110 DOI: 10.1021/acs.est.6b04842] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Imidacloprid (IMD) is the most widely used neonicotinoid insecticide found on environmental surfaces and in water. Analysis of surface-bound IMD photolysis products was performed using attenuated total reflectance Fourier transfer infrared (ATR-FTIR) analysis, electrospray ionization (ESI-MS), direct analysis in real time mass spectrometry (DART-MS), and transmission FTIR for gas-phase products. Photolysis quantum yields (ϕ) for loss of IMD were determined to be (1.6 ± 0.6) × 10-3 (1s) at 305 nm and (8.5 ± 2.1) × 10-3 (1s) at 254 nm. The major product is the imidacloprid urea derivative (IMD-UR, 84% yield), with smaller amounts of the desnitro-imidacloprid (DN-IMD, 16% yield) product, and gaseous nitrous oxide (N2O). Theoretical calculations show that the first step of the main mechanism is the photodissociation of NO2, which then recombines with the ground electronic state of IMD radical to form IMD-UR and N2O in a thermally driven process. The photolytic lifetime of IMD at a solar zenith angle of 35° is calculated to be 16 h, indicating the significant reaction of IMD over the course of a day. Desnitro-imidacloprid has been identified by others as having increased binding to target receptors compared to IMD, suggesting that photolysis on environmental surfaces increases toxicity.
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Affiliation(s)
- Kifle Z Aregahegn
- Department of Chemistry, University of California , Irvine, California 92697, United States
| | - Dorit Shemesh
- Department of Physical Chemistry and the Fritz Haber Research Center, The Hebrew University , Jerusalem 91904, Israel
| | - R Benny Gerber
- Department of Chemistry, University of California , Irvine, California 92697, United States
- Department of Physical Chemistry and the Fritz Haber Research Center, The Hebrew University , Jerusalem 91904, Israel
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4
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Chapleski RC, Zhang Y, Troya D, Morris JR. Heterogeneous chemistry and reaction dynamics of the atmospheric oxidants, O3, NO3, and OH, on organic surfaces. Chem Soc Rev 2016; 45:3731-46. [DOI: 10.1039/c5cs00375j] [Citation(s) in RCA: 75] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Heterogeneous chemistry of the most important atmospheric oxidants, O3, NO3, and OH, plays a central role in regulating atmospheric gas concentrations, processing aerosols, and aging materials.
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Affiliation(s)
| | - Yafen Zhang
- Department of Chemistry
- Virginia Tech
- Blacksburg
- USA
| | - Diego Troya
- Department of Chemistry
- Virginia Tech
- Blacksburg
- USA
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5
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Nah T, Zhang H, Worton DR, Ruehl CR, Kirk BB, Goldstein AH, Leone SR, Wilson KR. Isomeric Product Detection in the Heterogeneous Reaction of Hydroxyl Radicals with Aerosol Composed of Branched and Linear Unsaturated Organic Molecules. J Phys Chem A 2014; 118:11555-71. [DOI: 10.1021/jp508378z] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
| | | | - David R. Worton
- Aerosol Dynamics Inc., Berkeley, California 94710, United States
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6
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Nah T, Kessler SH, Daumit KE, Kroll JH, Leone SR, Wilson KR. Influence of Molecular Structure and Chemical Functionality on the Heterogeneous OH-Initiated Oxidation of Unsaturated Organic Particles. J Phys Chem A 2014; 118:4106-19. [DOI: 10.1021/jp502666g] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Theodora Nah
- Department
of Chemistry, University of California, Berkeley, California 94720, United States
- Chemical
Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Sean H. Kessler
- Department
of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Kelly E. Daumit
- Department
of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Jesse H. Kroll
- Department
of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
- Department
of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Stephen R. Leone
- Department
of Chemistry, University of California, Berkeley, California 94720, United States
- Chemical
Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
- Department
of Physics, University of California, Berkeley, California 94720, United States
| | - Kevin R. Wilson
- Chemical
Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
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7
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Kidd C, Perraud V, Finlayson-Pitts BJ. New insights into secondary organic aerosol from the ozonolysis of α-pinene from combined infrared spectroscopy and mass spectrometry measurements. Phys Chem Chem Phys 2014; 16:22706-16. [DOI: 10.1039/c4cp03405h] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Thermograms of desorbing species from size-fractionated SOA.
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Affiliation(s)
- Carla Kidd
- Department of Chemistry
- University of California
- Irvine, USA
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8
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Dilbeck CW, Finlayson-Pitts BJ. Hydroxyl radical oxidation of phospholipid-coated NaCl particles. Phys Chem Chem Phys 2013; 15:9833-44. [PMID: 23676928 DOI: 10.1039/c3cp51237a] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Biological organic compounds mixed with NaCl and other inorganic compounds in sea-salt aerosol particles react in air with oxidants such as ozone and hydroxyl (OH) radicals. Laboratory studies of model systems can provide insight into these reactions. We report here studies of the kinetics and mechanism of oxidation of unsaturated 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) on NaCl by gas phase OH in air at room temperature and 1 atm pressure using diffuse reflection infrared Fourier transform spectrometry (DRIFTS) and matrix-assisted laser desorption/ionization-time-of-flight-mass spectrometry (MALDI-TOF-MS) to identify possible structures of surface-bound reaction products. For comparison, some studies were also carried out on the saturated 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) on NaCl. The calculated concentration of hydroxyl radicals, generated by photolysis of isopropyl nitrite, was (1.6-6.4) × 10(8) radicals cm(-3). Surface-bound aldehydes, ketones, organic nitrates and nitrate ions were identified as products of these reactions and structures of potential products were proposed based on mechanistic considerations combined with the MALDI-TOF-MS and DRIFTS spectra. The loss rate of vinyl hydrogen, =C-H, at 3008 cm(-1) was used to obtain a lower limit for the rate constant (k1) for addition of OH to the double bond, k1 > (3 ± 1) × 10(-13) cm(3) molecule(-1) s(-1) (1s), corresponding to a reaction probability of γ(add) > (4 ± 1) × 10(-3) (1s). Assuming that abstraction from -CH2- groups in POPC is the same as for DPPC, the percentage of the reaction that occurs by addition is ~80%. This is similar to the percent addition predicted using structure-reactivity relationships for gas-phase reactions. Decreasing the amount of POPC relative to NaCl resulted in more nitrate ion formation and less relative loss of POPC, and increasing the OH concentration resulted in a more rapid loss of POPC and faster product formation. These studies suggest that under atmospheric conditions with an OH concentration of 5 × 10(6) radicals cm(-3), the lifetime of POPC with respect to OH is <6 days.
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Affiliation(s)
- Christopher W Dilbeck
- Department of Chemistry, University of California Irvine, Irvine, CA 92697-2025, USA
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9
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Huang J, Lee M, Lucero A, Kim J. Organic-Inorganic Hybrid Nano-laminates Fabricated by Ozone-assisted Molecular-atomic Layer Deposition. ACTA ACUST UNITED AC 2013. [DOI: 10.1002/cvde.201207041] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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10
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Nah T, Kessler SH, Daumit KE, Kroll JH, Leone SR, Wilson KR. OH-initiated oxidation of sub-micron unsaturated fatty acid particles. Phys Chem Chem Phys 2013; 15:18649-63. [DOI: 10.1039/c3cp52655k] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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11
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King KL, Paterson G, Rossi GE, Iljina M, Westacott RE, Costen ML, McKendrick KG. Inelastic scattering of OH radicals from organic liquids: isolating the thermal desorption channel. Phys Chem Chem Phys 2013; 15:12852-63. [DOI: 10.1039/c3cp51708j] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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12
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Moussa SG, Stern AC, Raff JD, Dilbeck CW, Tobias DJ, Finlayson-Pitts BJ. Experimental and theoretical studies of the interaction of gas phase nitric acid and water with a self-assembled monolayer. Phys Chem Chem Phys 2013; 15:448-58. [DOI: 10.1039/c2cp42405c] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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13
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Slade JH, Knopf DA. Heterogeneous OH oxidation of biomass burning organic aerosol surrogate compounds: assessment of volatilisation products and the role of OH concentration on the reactive uptake kinetics. Phys Chem Chem Phys 2013; 15:5898-915. [DOI: 10.1039/c3cp44695f] [Citation(s) in RCA: 99] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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14
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Dilbeck CW, Finlayson-Pitts BJ. Heterogeneous oxidation of a phosphocholine on synthetic sea salt by ozone at room temperature. Phys Chem Chem Phys 2012; 15:1990-2002. [PMID: 23258195 DOI: 10.1039/c2cp43665e] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The ozonolysis of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) adsorbed on salt mixtures as models for sea-salt particles was studied in real time using diffuse reflection infrared Fourier transform spectrometry (DRIFTS) at room temperature with and without added water vapor. The salt substrates were a mixture of MgCl(2)·6H(2)O with NaCl or a commercially available synthetic sea salt. Ozone concentrations ranged from (0.25 to 3.9) × 10(13) molecules cm(-3) (0.1-1.6 ppm). The major products identified by FTIR and confirmed using matrix-assisted laser desorption/ionization (MALDI) mass spectrometry were the secondary ozonide (SOZ) and a phospholipid aldehyde and carboxylic acid formed by scission of the double bond. The reaction probabilities for the two substrates were similar, γ = (6-7) × 10(-7), with an estimated overall uncertainty of a factor of two. The presence of water vapor decreased the yield of SOZ relative to the products formed by C[double bond, length as m-dash]C scission, but also increased the availability of the double bond for reaction, particularly on the less hygroscopic commercial sea-salt substrate. Thus, water not only affects the mechanisms and products, but also the structure of the phospholipid on the salt in a manner that affects its reactivity. The results of these studies suggest that the reactivity and products of oxidation of unsaturated phospholipids on sea-salt particles in air will be very sensitive to the nature and phase of the substrate, the amount of water present, and whether there is phase separation between the organics and the inorganic salt mixture.
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Affiliation(s)
- Christopher W Dilbeck
- Department of Chemistry, University of California Irvine, Irvine, CA 92697-2025, USA
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15
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Nishino N, Finlayson-Pitts BJ. Thermal and photochemical reactions of NO2 on chromium(iii) oxide surfaces at atmospheric pressure. Phys Chem Chem Phys 2012; 14:15840-8. [DOI: 10.1039/c2cp42292a] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Noriko Nishino
- Department of Chemistry, University of California, Irvine, California 92697-2025, USA
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16
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Xiao S, Bertram AK. Reactive uptake kinetics of NO3 on multicomponent and multiphase organic mixtures containing unsaturated and saturated organics. Phys Chem Chem Phys 2011; 13:6628-36. [PMID: 21369605 DOI: 10.1039/c0cp02682d] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
We investigated the reactive uptake of NO(3) (an important night-time oxidant in the atmosphere) on binary mixtures containing an unsaturated organic (methyl oleate) and saturated molecules (diethyl sebacate, dioctyl sebacate, and squalane) which we call matrix molecules. These studies were carried out to better understand the reactivity of unsaturated organics in multicomponent and multiphase atmospheric particles. For liquid binary mixtures the reactivity of methyl oleate depended on the matrix molecule. Assuming a bulk reaction, H(matrix)√(D(matrix)k(oleate)) varied by a factor of 2.7, and assuming a surface reaction H(matrix)(S)K(matrix)(S)k(oleate)(S) varied by a factor of 3.6, where H(matrix)√(D(matrix)k(oleate) and H(matrix)(S)K(matrix)(S)k(oleate)(S) are constants extracted from the data using the resistor model. For solid-liquid mixtures, the reactive uptake coefficient depended on exposure time: the uptake decreased by a factor of 10 after exposure to NO(3) for approximately 90 min. By assuming either a bulk or surface reaction, the atmospheric lifetime of methyl oleate in different matrices was estimated for moderately polluted atmospheric conditions. For all liquid mixtures, the lifetime was in the order of a few minutes (with an upper limit of 35 min). These lifetimes can be used as lower limits to the lifetimes in semi-solid mixtures. Our studies emphasize that the lifetime of unsaturated organics (similar to methyl oleate) is likely short if the particle matrix is in a liquid state.
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Affiliation(s)
- S Xiao
- Department of Chemistry, University of British Columbia, Vancouver, British Columbia, Canada
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17
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Waring C, Bagot PAJ, Costen ML, McKendrick KG. Reactive Scattering as a Chemically Specific Analytical Probe of Liquid Surfaces. J Phys Chem Lett 2011; 2:12-18. [PMID: 26295207 DOI: 10.1021/jz1013032] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
In this Perspective, we highlight some recent progress in the reactive scattering of "chemical probe" species such as atoms or small radicals from liquid surfaces. We emphasize in particular the evolution of this area from purely dynamical studies of the scattering mechanism. The mechanistic understanding that has now been gained is sufficiently mature to allow the same methods to be used as an effective analytical tool. The use of this approach to measure liquid-surface composition and structure is illustrated through the scattering of O((3)P) atoms from a common, imidazolium-based family of ionic liquids.
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Affiliation(s)
- Carla Waring
- School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, U.K
| | - Paul A J Bagot
- School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, U.K
| | - Matthew L Costen
- School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, U.K
| | - Kenneth G McKendrick
- School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, U.K
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18
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Iannone R, Xiao S, Bertram AK. Potentially important nighttime heterogeneous chemistry: NO3 with aldehydes and N2O5 with alcohols. Phys Chem Chem Phys 2011; 13:10214-23. [DOI: 10.1039/c1cp20294d] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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19
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Waring C, King KL, Bagot PAJ, Costen ML, McKendrick KG. Collision dynamics and reactive uptake of OH radicals at liquid surfaces of atmospheric interest. Phys Chem Chem Phys 2011; 13:8457-69. [DOI: 10.1039/c0cp02734k] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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20
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Raff JD, Szanyi J, Finlayson-Pitts BJ. Thermal and photochemical oxidation of self-assembled monolayers on alumina particles exposed to nitrogen dioxide. Phys Chem Chem Phys 2011; 13:604-11. [DOI: 10.1039/c0cp01041c] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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21
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Raff JD, Finlayson-Pitts BJ. Hydroxyl radical quantum yields from isopropyl nitrite photolysis in air. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2010; 44:8150-8155. [PMID: 20879762 DOI: 10.1021/es102218d] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Alkyl nitrites photolyze in air to yield alkoxy radicals and NO which, through secondary reactions, generate OH radicals. This photochemistry is important in the atmosphere and in laboratory studies where nitrites are often used as a source of OH. The overall quantum yield for hydroxyl radical formation from irradiation of isopropyl nitrite (i-C(3)H(7)ONO) between 300 and 425 nm in 1 atm air at 296 ± 2 K is reported for the first time. The OH radical was scavenged by reaction with CF(3)CF═CF(2) and the formation of CF(3)CFO and CF(2)O monitored as a function of time using Fourier transform infrared spectrometry. The quantum yield was found to be 0.54 ± 0.07 (2σ) and is independent of whether or not NO was added (up to 3 × 10(14) molecules cm(-3)) prior to photolysis to increase NO concentrations above those due to the photolysis of the nitrite. Ultraviolet-visible and infrared cross sections of i-C(3)H(7)ONO are also reported. These data on the OH quantum yields as well as the UV-visible and infrared cross sections for isopropyl nitrite are critical for quantitatively interpreting the results of laboratory studies where i-C(3)H(7)ONO is employed as an OH source as well as for assessing the role of alkyl nitrites in the chemistry of the troposphere.
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Affiliation(s)
- Jonathan D Raff
- Department of Chemistry, University of California, Irvine, California 92697-2025, USA
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