Grantee Research Project Results
Final Report: Atmospheric Chemistry of Volatile Organic Compounds and their Atmospheric Reaction Products
EPA Grant Number: R825252Title: Atmospheric Chemistry of Volatile Organic Compounds and their Atmospheric Reaction Products
Investigators: Atkinson, Roger , Tuazon, Ernesto C. , Arey, Janet
Institution: University of California - Riverside
EPA Project Officer: Hahn, Intaek
Project Period: November 1, 1996 through October 31, 1999 (Extended to October 31, 2000)
Project Amount: $387,254
RFA: Air Quality (1996) RFA Text | Recipients Lists
Research Category: Air Quality and Air Toxics , Air
Objective:
In this 3-year experimental program, we proposed to use the analytical methods available at the Air Pollution Research Center at the University of California, Riverside, to investigate the atmospheric chemistry of selected volatile organic compounds (VOCs) and of their reaction products. In particular, we proposed to use our PE SCIEX API III MS/MS direct air sampling, atmospheric pressure ionization tandem mass spectrometer (API-MS/MS) in conjunction with in situ Fourier transform infrared (FT-IR) spectroscopy, gas chromatography with flame ionization detection (GC-FID), gas chromatography with FTIR detection (GC-FTIR), combined gas chromatography-mass spectrometry (GC-MS), and product derivatization with GC-FID, GC-MS and GC-FTIR analyses to identify and quantify VOC reaction products. Specifically, during this 3-year experimental program we proposed to:? Study the products of the OH radical-initiated reactions of alkanes, including branched alkanes such as 2,2,4-trimethylpentane.
? Study the products of the gas-phase reactions of selected alkenes with OH radicals, NO3 radicals and O3.
? Investigate the atmospheric chemistry of hydroxycarbonyls formed from alkanes and alkenes. These experiments were to include rate constant measurements as well as product studies of a series of commercially-available and/or synthesized ?-, y-, o- and E- hydroxycarbonyls.
? Continue our investigation of the products of the gas-phase reactions of the OH radical with aromatic hydrocarbons in the presence and absence of NOx.
? Investigate the products formed from the atmospheric reactions of selected oxygenated compounds, including carbonyls, unsaturated dicarbonyls and phenolic compounds.
The experimental data obtained in this program was to provide critically important information concerning the products formed, and their yields, from the gas-phase reactions of selected VOCs and their first-generation reaction products with OH radicals, NO3 radicals and O3 under atmospheric conditions.
Summary/Accomplishments (Outputs/Outcomes):
The results of this project are summarized below by the VOC class investigated.1. Alkanes
Alkoxy radicals are formed from the OH radical-initiated reactions of alkanes and, therefore, one of our goals was to better understand the reactions of alkoxy radicals in the troposphere. As an extension of our earlier work on alkoxy radicals formed from the OH radical-initiated reactions of n-alkanes (Kwok, et al., Journal of Physical Chemistry 1996;100:214-219), we investigated the products of the reactions of the OH radical with cyclohexane (a cycloalkane) and 2,2,4-trimethylpentane (a branched alkane) and their deuterated analogs in the presence of NO, using gas chromatography and in situ API-MS to identify and quantify the reaction products.
Cyclohexane. Cyclohexanone and cyclohexyl nitrate (and their deuterated analogs) were identified and quantified, with formation yields of cyclohexanone and cyclohexyl nitrate from the cyclohexane reaction of 0.321 ? 0.035 and 0.165 ? 0.021, respectively, and with cyclohexanone-d10 and cyclohexyl nitrate-d11 formation yields from the cyclohexane-d12 reaction of 0.156 ? 0.017 and 0.210 ? 0.025, respectively. The remaining products must then arise from the decomposition and/or isomerization reactions of the intermediate cyclohexoxy radical. API-MS analyses of the cyclohexane and cyclohexane-d12 reactions showed the formation of cyclohexanone and cyclohexyl nitrate (and their deuterated analogs), together with ion peaks attributed to HC(O)CH2CH2CH2CH2CH2ONO2 (formed from reaction of NO with the HC(O)CH2CH2CH2CH2CH2O radical formed after decomposition of the cyclohexoxy radical) and HC(O)CH2CH(OH)CH2CH2CHO (formed after isomerization of the HC(O)CH2CH2CH2CH2CH2 radical). No evidence for isomerization of the cyclohexoxy radical was obtained from the API-MS analyses. The relative importance of the reactions of the cyclohexoxy radical are consistent with the reaction rates calculated as described by Atkinson (Journal of Physical Chemistry Reference Data 1997;26:215-290). In contrast to the reactions of the cyclohexoxy radical, where reaction with O2 and decomposition are competitive, it is predicted that for the cyclopentoxy and cycloheptoxy radicals formed from cyclopentane and cycloheptane, respectively, decomposition will dominate.
2,2,4-Trimethylpentane. Using in situ API-MS and API-MS/MS analyses in both positive and negative ion modes, the formation of hydroxynitrates of molecular weight 135, 177, and 191 (attributed to C4-, C7-, and C8-hydroxynitrates, respectively), hydroxycarbonyls of molecular weights 116, 130, and 144, and other products of molecular weight 128 (attributed to a C8-carbonyl) and 142 were observed. Using the API-MS in negative ion mode with NO2- as the reagent ions and 5-hydroxy-2-pentanone as an internal standard indicated that the molecular weight 116, 130, and 144 hydroxycarbonyl products account for 19 percent of the reaction products. The formation yields of acetone (0.58 ? 0.13) and 2-methylpropanal (0.28 ? 0.05) were measured by GC-FID from the 2,2,4-trimethylpentane reaction, together with upper limits to the formation yields of acetaldehyde (<0.04), 2,2-dimethylpropanal (<0.013) and 4,4-dimethyl-2-pentanone (<0.004). The products observed allow the detailed reactions subsequent to the initial OH radical reaction to be elucidated to a fairly complete extent.
2. Alkenes
Selected aspects of the atmospheric chemistry of alkenes were investigated, namely an investigation of the products and mechanisms of the OH and NO3 radical reactions of 1,3-butadiene, the simplest conjugated (and symmetric) diene; a study of 3-methyl-1-butene [(CH3)2CHCH=CH2] with a goal of measuring the fraction of the OH radical reaction proceeding by initial H-atom abstraction from the allylic C-H bond; and investigation of the formation of 1,2-hydroxycarbonyls from the reactions of OH radicals with selected alkenes in the presence and absence of NO.
3-Methyl-1-butene. While H-atom abstraction by OH radicals from the allylic C-H bonds of propene and 1-butene has been shown to be minor (estimated to be 3 percent and 7 percent, respectively, at 298 K and atmospheric pressure), use of C-H bond dissociation energy versus H-atom abstraction rate constant correlations suggests that H-atom abstraction from the allylic C-H bond in 3-methyl-1-butene could account for 30 percent of the overall reaction at 298 K. We therefore carried out a product study of the reaction of the OH radical with 3-methyl-1-butene in the presence of NO, with analyses of products by GC-FID, in situ FTIR absorption spectroscopy, and in situ API-MS. The products identified and quantified by GC-FID and in situ FT-IR absorption spectroscopy were HCHO, 2-methylpropanal, acetone, glycolaldehyde and methacrolein, with formation yields of 0.70 ? 0.06, 0.58 ? 0.08, 0.17 ? 0.02, 0.18 ? 0.03, and 0.033 ? 0.007, respectively. In addition, an IR absorption band due to organic nitrates was observed, consistent with API-MS observations of product ion peaks attributed to the -hydroxynitrates (CH3)2CHCH(ONO2)CH2OH and/or (CH3)2CHCH(OH)CH2ONO2 formed from the reactions of the corresponding -hydroxyalkyl peroxy radicals with NO. A formation yield of 0.15 for these nitrates was estimated using IR absorption band intensities for known organic nitrates. These products account for essentially all of the reacted 3-methyl-1-butene. Analysis of the potential reaction pathways involved shows that H-atom abstraction from the allylic C-H bond in 3-methyl-1-butene is a minor pathway which accounts for 5-10 percent of the overall OH radical reaction. The products observed from the OH radical addition pathway are consistent with the relative importance of the hydroxyalkoxy radical reactions predicted by the empirical estimation method proposed by Atkinson (Journal of Physical Chemistry Reference Data 1997;26:215-290).
1,3-Butadiene. Products were identified and quantified from the OH radical (in the presence of NO) and NO3 radical reactions with 1,3-butadiene using GC-FID, GC-MS, in situ FT-IR absorption spectroscopy and in situ API-MS, with the reactions of 1,3-butadiene-d6 also being studied using API-MS for product analyses. Acrolein, formaldehyde and furan were identified and quantified from the OH radical-initiated reaction with 1,3-butadiene, with formation yields of 0.58 ? 0.04, 0.62 ? 0.05, and 0.03-0.04, respectively. Organic nitrates were observed by FT-IR spectroscopy, with an estimated yield of 0.07 ? 0.03, and API-MS analyses indicated that these are mainly the hydroxynitrate HOCH2CH=CHCH2ONO2 and/or its isomers. API-MS analyses showed the formation of a hydroxycarbonyl of formula C4H6O2, most probably HOCH2CH=CHCHO and/or its isomers. The major products of the NO3 radical-initiated reaction were organic nitrates, and the API-MS analyses indicated the formation of unsaturated C4 hydroxycarbonyls, hydroxynitrates, carbonyl-nitrates and nitrooxyhydroperoxides, together with lower amounts of acrolein (molar yield of 0.04), HCHO (molar yield of 0.065) and furan (molar yield of 0.014) as obtained from GC-FID and in situ FT-IR analyses. The products observed from the OH radical and NO3 radical reactions with 1,3-butadiene are analogous to those we have previously reported on for the corresponding reactions of isoprene (Kwok, et al., Environmental Science and Technology 1995;29:2467-2469; International Journal of Chemical Kinetics 1996;28:925-934).
trans-2-Butene, trans-3-Hexene, 1-Butene and -Pinene. We observed that a number of hydroxyketones (but not 1,4-hydroxyketones) can be analyzed by gas chromatography without derivatization. Accordingly, we investigated the formation of 1,2-hydroxycarbonyls from the reactions of the OH radical with trans-2-butene, trans-3-hexene, 1-butene and -pinene in the presence and absence of NOx (forming OH radicals in the absence of NOx from the O3 reactions with the alkene being studied). The data obtained in the presence of NOx show that the intermediate 1,2-hydroxyalkoxy radicals decompose rather than reacting with O2 to form the 1,2-hydroxycarbonyls, and rate constant ratios kdecomposition/kO2 for the intermediate 1,2-hydroxyalkoxy radicals were derived, where kdecomposition and kO2 are the rate constants for the decomposition and reaction with O2 of the 1,2-hydroxyalkoxy radicals, respectively. In the absence of NOx, peroxy radical + peroxy radical reactions become important and we observed the formation of 1,2-hydroxycarbonyls and 1,2-diols under these conditions.
3. Aromatic Hydrocarbons
3-Hexene-2,5-dione is a potentially important product of the atmospheric photooxidation of certain aromatic hydrocarbons and fortunately is an unsaturated 1,4-dicarbonyl which can be analyzed by gas chromatography without prior derivatization. We have investigated the formation of 2,3-butanedione (biacetyl) and 3-hexene-2,5-dione (CH3C(O)CH=CHC(O)CH3) [and selected other products] from the reactions of the OH radical with p-xylene and 1,2,3- and 1,2,4-trimethylbenzene (in the presence of NO) as a function of the NO2 concentration, using GC-FID and GC-MS analyses. Formation yields have been measured using GC-FID for the formation of p-tolualdehyde, 2,5-dimethylphenol and 3-hexene-2,5-dione from p-xylene, 2,3-butanedione from 1,2,3-trimethylbenzene, and 2,3-butanedione and 3-hexene-2,5-dione from 1,2,4-trimethylbenzene. While the formation yields of p-tolualdehyde and 2,5-dimethylphenol from p-xylene showed no evidence for a dependence on the NO2 concentration (in agreement with an earlier (1991) study from this laboratory), the formation yields of ring-opened products from p-xylene and 1,2,3- and 1,2,4-trimethylbenzene decreased with increasing NO2 concentration. Furthermore, our formation yields for 3-hexene-2,5-dione were similar to those reported in previous studies for glyoxal (the expected co-product). Extrapolation of our product yields, obtained over the NO2 concentration range (0.5-13) x 1013 molecule cm-3, to NO2 concentrations representative of ambient indicates that, for example, in the presence of sufficient NO that peroxy radical + NO reactions dominate, the OH radical-initiated reaction of p-xylene leads to formation of (with percentage yields) p-tolualdehyde, 7 percent; p-methylbenzyl nitrate, 0.8 percent; 2,5-dimethylphenol, 13 percent; 3-hexene-2,5-dione + glyoxal, 32 percent; and 2-methyl-1,4-butendial + methylglyoxal, 12 percent, thus accounting for 65 percent of the reaction products. Similarly, we can account for 65-75 percent of the products from 1,2,3- and 1,2,4-trimethylbenzene under atmospheric conditions.
4. Oxygenated VOCs
We have carried out a number of studies of the atmospheric chemistry of oxygenated VOCs. These involved kinetic studies of the reactions of Cl atoms, OH radicals, NO3 radicals and O3 with various classes of oxygenated VOCs, and product studies of the reactions of OH radicals with esters, ethers and glycol ethers.
Acetates. The impetus for the study of the esters was provided by environmental chamber experiments to measure the ozone-forming potential of ethyl acetate, during which large yields of peroxyacetyl nitrate were observed together with low yields of acetaldehyde, inconsistent with previously expected reaction pathways of the intermediate alkoxy radicals. Products of the gas-phase reactions of the OH radical with ethyl acetate, isopropyl acetate and tert-butyl acetate in the presence of NO were investigated using in situ FT-IR spectroscopy and GC-FID. The products identified and their molar formation yields (corrected for secondary reactions with the OH radical) were: acetic acid (0.96 ? 0.08) from ethyl acetate; acetic acid (0.09 ? 0.03), acetic anhydride (0.76 ? 0.07) and acetone (0.24 ? 0.02) from isopropyl acetate; and acetic anhydride (0.49 ? 0.05) and acetone (0.20 ? 0.02) from tert-butyl acetate. Consideration of the potential reaction pathways of the intermediate alkoxy radicals leads to the conclusion that alkoxy radicals of structure RC(O)OCH() can undergo a rapid rearrangement and decomposition ( -ester rearrangement) to RC(O)OH plus O,
RC(O)OCH() RC(O)OH + O
presumably via a 5-membered ring transition state. However, our product data
provided no evidence for the analogous -ester rearrangement proceeding via a
6-membered transition state, although the possibility that this reaction could
occur was not ruled out.
Reactions of Alcohols and Ethers with the
NO3 Radical. While of minor importance as a
tropospheric loss process, rate constants for the reactions of the NO3 radical with alcohols and ethers are reported to be
approximately two orders of magnitude higher than those for the reactions of the
corresponding alkanes. We used a relative rate method to measure rate constants
for the gas-phase reactions of the NO3 radical with
methacrolein, a series of ethers, glycol ethers, alcohols, and chloroalkenes at
298 ? 2 K and atmospheric pressure of air. The rate constants determined (in
units of 10-16 cm3 molecule-1 s-1) were: methacrolein, 33 ? 10; diethyl ether,
31 ? 10; di-n-propyl ether, 49 ? 16; di-isopropyl ether, 40 ? 13; ethyl
tert-butyl ether, 45 ? 14; 1-methoxy-2-propanol, 15 ? 5; 2-butoxyethanol, 31 ?
11; 1-propanol, 21 ? 8; 2-propanol, 17 ? 6; 1-butanol, 27 ? 10; 2-butanol, 25 ?
8; 4-heptanol, 60 ? 20; cis-1,2- dichloroethene, 1.3 ? 1.3; 1,1-dichloroethene,
18 (with an uncertainty of a factor of 1.5); trichloroethene, 3.6 (with an
uncertainty of a factor of 1.6); tetrachloroethene, <1.8; and
3-chloropropene, 5.8 (with an uncertainty of a factor of 1.5). Carbonyl products
of the alcohol reactions arising after H-atom abstraction at the carbon atom to
which the -OH group is attached were observed, and rate constants for this
reaction pathway obtained. Significant discrepancies with the literature data
occurred for 2-propanol, ethyl tert-butyl ether and 3-chloropropene, with our
relative rate constants for these compounds being factors of 2, 2, and 8 lower,
respectively, than previously reported absolute rate constant
determinations.
Products and Mechanisms of OH Radical Reactions with Ethers and Glycol Ethers. We have used GC-FID and in situ API-MS to identify and quantify the products of the reactions of the OH radical with n-butyl methyl ether and with 2-isopropoxyethanol. The products identified and quantified were: from n-butyl methyl ether, methyl formate (0.51 ? 0.11), propanal (0.43 ? 0.06), butanal (0.045 ? 0.010), methyl butyrate, 0.016, and CH3C(O)CH2CH2OCH3 and/or CH3CH2C(O)CH2OCH3, 0.19 ? 0.04; and from 2-isopropoxyethanol, isopropyl formate, 0.57 ? 0.05, and 2-hydroxyethyl acetate, 0.44 ? 0.05. These product data were used together with literature data for the OH radical reactions with ethers and glycol ethers (including previous work from this laboratory) to assess the relative importance of decomposition, isomerization and reaction with O2 of the alkoxy radicals of structures ROC()< and ROCC()<, and to derive estimation methods to allow the rates of these alkoxy radical reactions to be calculated.
Reactions of Ethers with Cl Atoms and OH Radicals. We have used relative rate methods to determine the room temperature rate constants for the reactions of OH radicals and Cl atoms with di-n-propyl ether, di-n-propyl ether-d14, di-n-butyl ether and di-n-butyl ether-d18. The rate constants for the di-n-propyl ether and di-n-butyl ether reactions are in agreement with literature values, although our rate constant for the OH radical reaction with di-n-butyl ether is around 10-20% higher than most previous measurements. For both the OH radical and Cl atom reactions, we measured significant deuterium isotope effects, with values of kH/kD of 2.0 for the OH radical reactions and 1.3 for the Cl atom reactions. These deuterium isotope effects mean that for both the OH radical and Cl atom reactions, the rate-determining step involves H-atom abstraction.
Reactions of Aldehyes with OH and NO3 Radicals. We have measured rate constants for the gas-phase reactions of OH radicals and NO3 radicals with propanal, butanal, pentanal and hexanal at room temperature. The rate constants (in cm3 molecule-1 s-1 units) ranged from 2.02 x 10-11 for propanal to 3.17 x 10-11 for hexanal for the OH radical reactions and from 7.1 x 10-15 for propanal to 1.49 x 10-14 for hexanal for the NO3 radical reactions, and show (in agreement with the earlier literature of D'Anna and Nielsen, Journal of Chemical Society?Faraday Transactions 1997;93: 3479-3483) that the rate constants for the NO3 radical reactions increase markedly with increasing carbon number, in contrast to the OH radical reactions.
Reactions of Hydroxycarbonyls with OH and NO3 Radicals and O3. We have also measured rate constants for the reactions of OH radicals, NO3 radicals and O3 with the hydroxyketones 1-hydroxy-2-butanone, 3-hydroxy-2-butanone, 1-hydroxy-3-butanone, 1-hydroxy-2-methyl-3-butanone, 3-hydroxy-3-methyl-2-butanone and 4-hydroxy-3-hexanone at room temperature. The measured rate constants for the OH radical reactions (in units of 10-12 cm3 molecule-1 s-1) are: 1-hydroxy-2-butanone, 7.7 ? 1.7; 3-hydroxy-2-butanone, 10.3 ? 2.2; 1-hydroxy-3-butanone, 8.1 ? 1.8; 1-hydroxy-2-methyl-3-butanone, 16.2 ? 3.4; 3-hydroxy-3-methyl-2-butanone, 0.94 ? 0.37; and 4-hydroxy-3-hexanone, 15.1 ? 3.1, where the indicated errors include the estimated uncertainties in the rate constant for the reference compound. The NO3 radical and O3 reactions are slow, and the OH radical reactions will be the dominant atmospheric gas-phase loss process for these hydroxycarbonyls, with calculated lifetimes for the OH radical reactions of 0.7-1.5 days, apart from 3-hydroxy-3-methyl-2-butanone for which the calculated lifetime is 12 days due to reaction with OH radicals.
Reactions of Diols with the OH Radical. We used a relative rate method
to determine rate constants at 296 ? 2 K for the gas-phase reactions of OH
radicals with 1,2-butanediol, 2,3-butanediol, 1,3-butanediol and
2-methyl-2,4-pentanediol, of (in units of 10-12 cm3 molecule-1 s-1) 27.0 ? 5.6,
23.6 ? 6.3, 33.2 ? 6.8, and 27.7 ? 6.1, respectively, where the error limits
include the estimated overall uncertainty of ?20 percent in the rate constant
for the reference compound. GC-FID analyses showed the formation of
1-hydroxy-2-butanone from 1,2-butanediol, 3-hydroxy-2-butanone from
2,3-butanediol, 1-hydroxy-3-butanone from 1,3-butanediol, and
4-hydroxy-4-methyl-2-pentanone from 2-methyl-2,4-pentanediol, with formation
yields of 0.66 ? 0.11, 0.89 ? 0.09, 0.50 ? 0.09 and 0.47 ? 0.09, respectively,
where the indicated errors are the estimated overall uncertainties. These
hydroxyketone products are formed by initial H-atom abstraction from -CH(OH)-
groups, followed by reaction of the -hydroxyalkyl radicals with O2; for
example:
OH + CH3CH(OH)CH(OH)CH3 CH3 (OH)CH(OH)CH3 + H2O
CH3 (OH)CH(OH)CH3 + O2 CH3C(O)CH(OH)CH3 + HO2
Implications
The kinetic and product data obtained in this project significantly enhance our knowledge of the atmospheric chemistry of VOCs. To take two examples: (1) the product data on the ethers and glycol ethers has allowed a revised empirical estimation method for the atmospheric reactions of alkoxy radicals to be proposed, and predictions from this estimation method are in generally good agreement with experimental data obtained since this revised estimation method was proposed for several classes of VOCs; and (2) our product data for reactions of OH radicals with aromatic hydrocarbons now allows 65-75% of the reaction products to be quantified under atmospheric conditions.
Journal Articles on this Report : 13 Displayed | Download in RIS Format
Other project views: | All 27 publications | 13 publications in selected types | All 13 journal articles |
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Aschmann SM, Chew AA, Arey J, Atkinson R. Products of the gas-phase reaction of OH radicals with cyclohexane: Reactions of the cyclohexoxy radical. Journal of Physical Chemistry A 1997;101(43):8042-8048. |
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Aschmann SM, Atkinson R. Products of the gas-phase reactions of the OH radical with n-butyl methyl ether and 2-isopropoxyethanol: Reactions of ROC(O)< radicals. International Journal of Chemical Kinetics 1999;31(7):501-513. |
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Aschmann SM, Arey J, Atkinson R. Atmospheric chemistry of selected hydroxycarbonyls. Journal of Physical Chemistry A Molecules 2000;104(17):3998-4003. |
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Aschmann SM, Arey J, Atkinson R. Formation of β-hydroxycarbonyls from the OH radical-initiated reactions of selected alkenes. Environmental Science & Technology 2000;34(9):1702-1706. |
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Aschmann Sm, Arey J, Atkinson R. Products and mechanism of the reaction of OH radicals with 2,2,4-trimethylpentane in the presence of NO. Environmental Science and Technology 2002;36(4):625-632. |
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Atkinson R, Tuazon EC, Aschmann SM. Products of the gas-phase reaction of the OH radical with 3-methyl-1-butene in the presence of NO. International Journal of Chemical Kinetics 1998;30(8):577-587. |
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Bethel HL, Atkinson R, Arey J. Products of the gas-phase reactions of OH radicals with p-xylene and 1,2,3- and 1,2,4-trimethylbenzene: effect of NO2 concentration. Journal of Physical Chemistry A 2000;104(39):8922-8929. |
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Bethel HL, Atkinson R, Arey J. Kinetics and products of the reactions of selected diols with the OH radical. International Journal of Chemical Kinetics 2001;33(5):310-316. |
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Chew AA, Atkinson, Aschmann SM. Kinetics of the gas-phase reactions of NO3 radicals with a series of alcohols, glycol ethers, ethers, and chloroalkenes. Journal of the Chemical Society Faraday Transactions 1998;94(8):1083-1089. |
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Harry C, Atkinson R, Arey J. Rate constants for the reactions of OH radicals and Cl atoms with di-n-propyl ether and di-n-butyl ether and their deuterated analogs. International Journal of Chemical Kinetics 1999;31(6):425-431. |
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Papagni C, Arey J, Atkinson R. Rate constants for the gas-phase reactions of a series of C3—C6 aldehydes with OH and NO3 radicals. International Journal of Chemical Kinetics 2000;32(2):79-84. |
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Tuazon EC, Aschmann SM, Atkinson R, Carter WPL. The reactions of selected acetates with the OH radical in the presence of NO: Novel rearrangement of alkoxy radicals of structure RC(O)OCH(O)R. Journal of Physical Chemistry A 1998;102(13):2316-2321. |
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Tuazon EC, Alvarado A, Aschmann SM, Atkinson R, Arey J. Products of the gas-phase reactions of 1,3-butadiene with OH and NO3 radicals. Environmental Science and Technology 1999;33(20):3586-3595. |
R825252 (1998) R825252 (1999) R825252 (2000) R825252 (Final) |
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Supplemental Keywords:
hydroxyl radical, nitrate radical, ozone, atmospheric chemistry, kinetics, reaction products, reaction mechanisms., RFA, Scientific Discipline, Air, air toxics, Environmental Chemistry, tropospheric ozone, Atmospheric Sciences, exposure and effects, spectroscopic studies, VOCs, air quality data, air sampling, gas chromatography, chemical kinetics, atmospheric chemical cycles, alkenes, atmospheric monitoring, infrared spectroscopy, atmospheric reaction products, hydroxycarbonylsProgress and Final Reports:
Original AbstractThe perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.