2000 Progress Report: Atmospheric Chemistry of Volatile Organic Compounds and their Atmospheric Reaction Products

EPA Grant Number: R825252
Title: Atmospheric Chemistry of Volatile Organic Compounds and their Atmospheric Reaction Products
Investigators: Atkinson, Roger , Arey, Janet , Tuazon, Ernesto C.
Institution: University of California - Riverside
EPA Project Officer: Shapiro, Paul
Project Period: November 1, 1996 through October 31, 1999 (Extended to October 31, 2000)
Project Period Covered by this Report: November 1, 1999 through 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 (FTIR) 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 will include rate constant measurements as well as product studies of a series of commercially-available and/or synthesized -, -, -, and -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 to be obtained in this program will 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.

Progress Summary:

During the fourth year, no-cost extension of this project, we have completed the studies discussed below.

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 percetn of the products from 1,2,3- and 1,2,4-trimethylbenzene under atmospheric conditions. A manuscript describing this study has been published in the Journal of Physical Chemistry A.

Oxygenated VOCs.
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

A manuscript describing this study is "in-press" in the International Journal of Chemical Kinetics.

Future Activities:

Prepare and submit the final report for the grant.


Journal Articles on this Report : 12 Displayed | Download in RIS Format

Other project views: All 27 publications 13 publications in selected types All 13 journal articles
Type Citation Project Document Sources
Journal Article 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. R825252 (1998)
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  • Abstract: American Chemical Society Publications Abstract
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  • Journal Article 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. R825252 (1998)
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  • Abstract: InterScience Abstract
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  • Journal Article Aschmann SM, Arey J, Atkinson R. Atmospheric chemistry of selected hydroxycarbonyls. Journal of Physical Chemistry A Molecules 2000;104(17):3998-4003. R825252 (1998)
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  • Full-text: American Chemical Society Full Text
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  • Abstract: American Chemical Society Abstract
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  • Journal Article 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. R825252 (1998)
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  • Abstract: American Chemical Society Publications Abstract
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  • Journal Article 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. R825252 (1998)
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  • Abstract from PubMed
  • Journal Article 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. R825252 (1998)
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    R826371C007 (Final)
  • Abstract: American Chemical Society Abstract
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  • Journal Article 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. R825252 (1998)
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    R826371C007 (Final)
  • Abstract: InterScience Abstract
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  • Journal Article 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. R825252 (1998)
    R825252 (1999)
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  • Abstract: RSC Publishing Abstract
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  • Journal Article 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. R825252 (1998)
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  • Abstract: InterScience Abstract
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  • Journal Article 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. R825252 (1998)
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  • Abstract: InterScience Abstract
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  • Journal Article 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. R825252 (1998)
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  • Abstract: American Chemical Society Publications Abstract
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  • Journal Article 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)
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    R825252 (Final)
  • Abstract: American Chemical Society Publications Abstract
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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, gas chromatography, air sampling, air quality data, chemical kinetics, atmospheric chemical cycles, alkenes, infrared spectroscopy, atmospheric monitoring, atmospheric reaction products, hydroxycarbonyls

    Progress and Final Reports:

    Original Abstract
  • 1997
  • 1998 Progress Report
  • 1999 Progress Report
  • Final Report