A study of the atmospheric reactions of 1,3-dichloropropene and other selected organochlorine compounds

Rate constants for the reactions of OH radicals and NO3 radicals with O,O-diethyl methylphosphonothioate [(C(2)H(5)O)(2)P(S)CH(3); DEMPT] and O,O,O-triethyl phosphorothioate [(C(2)H(5)O)(3)PS; TEPT] have been measured using relative rate methods at atmospheric pressure of air over the temperature range 296-348 K for the OH radical reactions and at 296 +/- 2 K for the NO(3) radical reactions. At 296 +/- 2 K, the rate constants obtained for the OH radical reactions (in units of 10(-11) cm(3) molecule(-1) s(-1)) were 20.4 +/- 0.8 and 7.92 +/- 0.27 for DEMPT and TEPT, respectively, and those for the NO(3) radical reactions (in units of 10(-15) cm(3) molecule(-1) s(-1)) were 2.01 +/- 0.20 and 1.03 +/- 0.10, respectively. Upper limits to the rate constants for the reactions of O(3) with DEMPT and TEPT of <6 x 10(-20) cm(3) molecule(-1) s(-1) were determined in each case. Rate constants for the OH radical reactions, measured relative to k(OH + alpha-pinene) = 1.21 x 10(-11) e(436/T) cm(3) molecule(-1) s(-1), resulted in the Arrhenius expressions k(OH + DEMPT) = 1.08 x 10(-11) e(871+/-25)/T cm(3) molecule(-1) s(-1) and k(OH + TEPT) = 8.21 x 10(-13) e(1353+/-49)/T cm(3) molecule(-1) s(-1) over the temperature range 296-348 K, where the indicated errors are two least-squares standard deviations and do not include the uncertainties in the reference rate constant. Diethyl methylphosphonate was identified and quantified from the OH radical and NO(3) radical reactions with DEMPT, with formation yields of 21 +/- 4%, independent of temperature, from the OH radical reaction and 62 +/- 11% from the NO(3) radical reaction at 296 +/- 2 K. Similarly, triethyl phosphate was identified and quantified from the OH radical and NO(3) radical reactions with TEPT, with formation yields of 56 +/- 9%, independent of temperature, from the OH radical reaction and 78 +/- 15% from the NO(3) radical reaction at 296 +/- 2 K.

The focus of this contract was to investigate selected aspects of the atmospheric chemistry of volatile organic compounds (VOCs) emitted into the atmosphere from energy-related sources as well as from biogenic sources. The classes of VOCs studied were polycyclic aromatic hydrocarbons (PAHs) and nitro-PAHs, the biogenic VOCs isoprene, 2-methyl-3-buten-2-ol and cis-3-hexen-1-ol, alkenes (including alkenes emitted from vegetation) and their oxygenated atmospheric reaction products, and a series of oxygenated carbonyl and hydroxycarbonyl compounds formed as atmospheric reaction products of aromatic hydrocarbons and other VOCs. Large volume reaction chambers were used to investigate the kinetics and/or products of photolysis and of the gas-phase reactions of these organic compounds with hydroxyl (OH) radicals, nitrate (NO3) radicals, and ozone (O3), using an array of analytical instrumentation to analyze the reactants and products (including gas chromatography, in situ Fourier transform infrared spectroscopy, and direct air sampling atmospheric pressure ionization tandem mass spectrometry). The following studies were carried out. The photolysis rates of 1- and 2-nitronaphthalene and of eleven isomeric methylnitronaphthalenes were measured indoors using blacklamp irradiation and outdoors using natural sunlight. Rate constants were measured for the gas-phase reactions of OH radicals, Cl atoms and NO3 radicals with naphthalene, 1- and 2-methylnaphthalene, 1- and 2-ethylnaphthalene and the ten dimethylnaphthalene isomers. Rate constants were measured for the gas-phase reactions of OH radicals with four unsaturated carbonyls and with a series of hydroxyaldehydes formed as atmospheric reaction products of other VOCs, and for the gas-phase reactions of O3 with a series of cycloalkenes. Products of the gas-phase reactions of OH radicals and O3 with a series of biogenically emitted VOCs were identified and quantified. Ambient atmospheric measurements of the concentrations of a number of PAHs, nitro-PAHs, nitrated polycyclic aromatic compounds and biogenic VOCs were carried out in the Los Angeles air basin. In addition to these laboratory and ambient field studies, two literature reviews of VOC atmospheric chemistry and of the kinetics of the reactions of OH radicals with alkanes were also carried out. This research has been reported in 15 peer-reviewed publications.

Rate constants for the gas-phase reactions of OH radical, NO(3) radical, and ozone with allyl alcohol (AAL) and allyl isocyanate (AIC) have been measured using relative rate methods at atmospheric pressure in purified air. The experimental Arrhenius expression obtained for the reaction of the OH radical with AAL is (1.68 +/- 0.89) x 10(-12) x exp(1100/T) cm(3) molecule(-1) s(-1), for T = 282-315 K; the Arrhenius expression for the reaction of OH radical with AIC is (1.94 +/- 1.04) x 10(-14) x exp(2207/T) cm(3) molecule(-1) s(-1), for T = 282-317 K, where the indicated errors are one least-squares standard deviation. All OH radical reaction rate constants have been measured relative to k(OH + alpha-pinene) and k(OH + 1,3,5-trimethylbenzene). The rate constant for the gas-phase reaction of OH radical with allyl alcohol-d(6) isotopomer (AAL-d(6)) has been measured at T = 298 K, and the value is 5.10 x 10(-11) cm(3) molecule(-1) s(-1). The kinetic isotope effect is small, with k(AAL)/k(AAL-d(6)) = 1.32. Rate constants for the gas-phase reactions of NO(3) radical with AAL [relative to k(NO(3) +methacrolein)] and O(3) [relative to k(O(3) + beta-pinene)] have been measured, and the values are 7.7 x 10(-15) cm(3) molecule(-1) s(-1) at T = 298 K and 1.6 x 10(-17) cm(3) molecule(-1) s(-1) at T = 296 K, respectively. Rate constants for the gas-phase reactions of NO(3) radical and O(3) with AIC have been measured, and the values are 9.4 x 10(-16) cm(3) molecule(-1) s(-1) at T = 299 K and 5.54 x 10(-18) cm(3) molecule(-1) s(-1) at T = 299 K, respectively. Multireference ab initio calculations at the MRMP2/6-311G(d,p) level have been carried out for reactions of OH radical with AAL and AIC. Results indicate that prereactive hydrogen bonded complexes form in the entrance channels for these reactions.

Products of the gas-phase reactions of O3 with cyclohexene and cyclohexene-d10 were investigated in the presence of OH radical scavengers by gas chromatography with flame ionization detection, combined gas chromatography−mass spectrometry, in situ Fourier transform infrared spectroscopy, and in situ atmospheric pressure ionization mass spectrometry (API-MS). Cyclohexane and cyclohexane-d12 were used as OH radical scavengers in the experiments using API-MS analyses to allow products formed from the O3 reactions with cyclohexene and cyclohexene-d10 to be differentiated from those from the reactions of OH radicals with cyclohexane and cyclohexane-d12. The gas-phase products observed from the reaction of O3 with cyclohexene in the presence of an OH radical scavenger were pentanal (23.6 ± 1.8%); OH radicals (54 ± 8%); formic acid (3.5% initial yield); glutaraldehyde [HC(O)CH2CH2CH2CHO]; adipaldehyde [HC(O)CH2CH2CH2CH2CHO], a C6H10O3 product attributed to the secondary ozonide; a C5H7O2(OOH) product, a molecular weight 130 hydroxydicarbonyl; and a molecular weight 116 carbonyl compound. Yields of pentanal-d10, OD radicals, and DC(O)OH from the reaction of O3 with cyclohexene-d10, of 16.4 ± 1.4%, 50 ± 7%, and 1.6% (initial), respectively, were obtained. Our data indicate that reactions of the Criegee intermediate to form pentanal (plus CO2) and an OH radical plus organic radical coproduct account for 78 ± 9% of the reaction pathways, with the organic radical coproduct reacting to form (in part) glutaraldehyde. Adipaldehyde can be formed from reaction of the thermalized Criegee intermediate (presumably the anti-intermediate) with water vapor. OH (or OD) radical formation yields were also measured from the reactions of O3 with propene (40 ± 6%), propene-d6 (27 ± 4%) α-pinene (86 ± 13%), and 2,3-dimethyl-2-butene (107 ± 16%).

A previous technique for the calculation of rate constants for the gas‐phase reactions of the OH radical with organic compounds has been updated and extended to include sulfur‐ and nitrogen‐containing compounds. The overall OH radical reaction rate constants are separated into individual processes involving (a) H‐atom abstraction from CH and OH bonds in saturated organics, (b) OH radical addition to &gt;CC&lt; and CC unsaturated bonds, (c) OH radical addition to aromatic rings, and (d) OH radical interaction with NH2, &gt;NH, &gt;N, SH, and S groups. During its development, this estimation technique has been tested against the available database, and only for 18 out of a total of ca. 300 organic compounds do the calculated and experimental room temperature rate constants disagree by more than a factor of 2. This suggests that this technique has utility in estimating OH radical reaction rate constants at room temperature and atmospheric pressure of air, and hence atmospheric lifetimes due to OH radical reaction, for organic compounds for which experimental data are not available. In addition, OH radical reaction rate constants can be estimated over the temperature range ca. 250–1000 K for those organic compounds which react via H‐atom abstraction from CH and OH bonds, and over the temperature range ca. 250–500 K for compounds containing &gt;CC&lt; bond systems.

Rate constants for the gas-phase reactions of the cyclic organosulfur compounds 1,4-thioxane and 1,4-dithiane with NO(3) radicals and O(3) have been measured at 296 +/- 2 K, and rate constants for their reactions with OH radicals have been measured over the temperature range 278-350 K. Relative rate methods were used to measure rate constants for the OH radical and NO(3) radical reactions. The OH radical reaction in the presence of NO(x) and, to a lesser extent, the NO(3) radical reaction were subject to secondary reactions leading to additional removal of 1,4-thioxane and/or 1,4-dithiane. The rate constants obtained for the NO(3) radical and O(3) reactions at 296 +/- 2 K were (5.1 +/- 1.1) x 10(-14) cm(3) molecule(-1) s(-1) and <2 x 10(-19) cm(3) molecule(-1) s(-1), respectively, for 1,4-thioxane and (5.9 +/- 1.8) x 10(-14) cm(3) molecule(-1) s(-1) and <2.5 x 10(-19) cm(3) molecule(-1) s(-1), respectively, for 1,4-dithiane. For the OH radical reactions, the temperature-dependent rate expressions obtained were k(OH + 1,4-thioxane) = 2.54 x 10(-12) e((619+/-51)/T) cm(3) molecule(-1) s(-1) (278-349 K) and k(OH + 1,4-dithiane) = 3.71 x 10(-12) e((621+/-163)/T) cm(3) molecule(-1) s(-1) (278-350 K), with 298 K rate constants of (2.03 +/- 0.41) x 10(-11) cm(3) molecule(-1) s(-1) for 1,4-thioxane and (2.98 +/- 0.75) x 10(-11) cm(3) molecule(-1) s(-1) for 1,4-dithiane. For the experimental conditions employed, aerosol formation from the OH radical-initiated reactions of both 1,4-thioxane and 1,4-dithiane was important, accounting for approximately 60% of the organosulfur compounds reacted in both the presence and absence of NO(x). The data obtained here for 1,4-thioxane and 1,4-dithiane are compared with literature data for the corresponding reactions of simple acyclic alkyl sulfides and ethers.

The gas-phase reactions of OH(X2Π) radicals with di-i-propoxymethane (DiPM) and di-sec-butoxymethane (DsBM) have been studied in argon in the temperature range 295–700 K at total pressures between 50 and 400 Torr. OH radicals were generated by excimer laser photolysis of H2O2 and were detected by laser-induced fluorescence. Within the investigated ranges, the reactions of OH(X2Π) radicals with DiPM and DsBM were found to be independent of total pressure. Weak dependencies of the rate coefficients on temperature were observed. Bimolecular rate coefficients for the reactions of OH(X2Π) with DiPM and DsBM at 298 K of kOH+DiPM=(3.47±0.20)×10-11 cm3 s-1 and kOH+DsBM=(4.25±0.13)×10-11 cm3 s-1, respectively, have been determined. In order to describe the kinetics of the reactions of OH radicals with DiPM and DsBM as well as analogous acetals, a structure activity relationship (SAR) technique established for other reactant classes has been modified and applied. Compared to the former SAR method, which does not yield satisfying results for oxygenated VOCs (volatile organic compounds), the present calculations lead to much better agreement with the experimental data for dialkylacetals of the type R–O–CH2–O–R.

Rate constants for the reactions of O3 and OH radicals with furan and thiophene have been determined at 298 ± 2 K. The rate constants obtained for the O3 reactions were (2.42 ± 0.28) × 10−18 cm3/molec·s for furan and &lt;6 ×10−20 cm3/molec·s for thiophene. The rate constants for the OH radical reactions, relative to a rate constant for the reaction of OH radicals with n‐hexane of (5.70 ± 0.09) × 10−12 cm3/molec·s, were determined to be (4.01 ± 0.30) × 10−11 cm3/molec·s for furan and (9.58 ± 0.38) × 10−12 cm3/molec·s for thiophene. There are to date no reported rate constant data for the reactions of OH radicals with furan and thiophene or for the reaction of O3 with furan. The data are compared and discussed with respect to those for other alkenes, dialkenes, and heteroatom containing organics.

Linalool [(CH3)2CCHCH2CH2C(CH3)(OH)CHCH2] is a terpene derivative emitted from vegetation, including orange blossoms and certain trees and vegetation in the Mediter ranean area. Linalool reacts rapidly in the gas phase in the troposphere with OH radicals, NO3 radicals, and O3, with a calculated lifetime due to these reactions of ∼1 h or less. The products of these gas-phase reactions have been studied in ∼6500−7900-L Teflon chambers using gas chro matography, in situ Fourier transform infrared absorption spectroscopy, and direct air sampling atmospheric pres sure ionization tandem mass spectrometry. The products identified and their formation yields are as follows: from the OH radical reaction, acetone, 0.505 ± 0.047; 6-methyl-5-hepten-2-one, 0.068 ± 0.006; 4-hydroxy-4-methyl-5-hexen-1-al (or its cyclized isomer), 0.46 ± 0.11; from the NO3 radical reaction, acetone, 0.225 ± 0.052; 4-hydroxy-4-methyl-5-hexen-1-al (or its cyclized isomer), 0.191 ± 0.051; and a non-quantified nitrooxycarbonyl; from the O3 reaction, acetone, 0.211 ± 0.024; 4-hydroxy-4-methyl-5-hexen-1-al (or its cyclized isomer), 0.85 ± 0.14; 5-ethenyldihydro-5-methyl-2(3H)-furanone, 0.126 ± 0.025; and HCHO, 0.36 ± 0.06. The formation routes to these products and the reaction mechanisms are discussed. Despite the complexity of linalool, a C10-hydroxydiene, the reaction products observed and quantified account for a significant fraction of the carbon reacted (especially for the OH radical and O3 reactions), with the carbon balances being 53 ± 8% for the OH radical reaction in the presence of NO, 20 ± 4% (plus the non-quantified, but anticipated to be major, nitrooxycarbonyl) for the NO3 radical reaction, and 78 ± 10% for the O3 reaction.

Using a relative rate method, rate constants have been measured for the gas-phase reactions of the volatile carbamates CH3NHC(O)OCH3, CH3NHC(O)OCH2CH3, CH3CH2NHC(O)OCH3 and CH3CH2NHC(O)OCH2CH3 and the lactates CH3CH(OH)C(O)OCH3, and CH3CH(OH)C(O)OCH2CH3 with the OH radical at 296 ± 2 K of (in units of 10-12 cm3 molecule-1 s-1) 4.3 ± 1.2, 8.3 ± 2.2, 10.5 ± 2.9, 14.4 ± 3.7, 2.8 ± 0.8, and 3.9 ± 1.1, respectively, where the error limits include the estimated overall uncertainties in the rate constants for the reference compounds. Rate constants were also measured for the reactions of the carbamates with NO3 radicals and O3, with respective NO3 radical and O3 reaction rate constants (in cm3 molecule-1 s-1 units) of CH3NHC(O)OCH3, (8.5 ± 3.2) × 10-16 and <4 × 10-20; CH3NHC(O)OCH2CH3, (9.4 ± 3.5) × 10-16 and <4 × 10-20; CH3CH2NHC(O)OCH3, (1.8 ± 0.8) × 10-15 and <6 × 10-20; and CH3CH2NHC(O)OCH2CH3, (2.6 ± 1.3) × 10-15 and <3 × 10-20. The OH radical reaction rate constants for the carbamates have been used to extend a previously developed estimation method to carbamates of the structure R1NHC(O)OR2 (where R1 and R2 are alkyl groups only), allowing OH radical reaction rate constants and hence tropospheric lifetimes to be calculated for carbamates used in agriculture for which experimental data are not available.

As the result of biogenic and anthropogenic activities, large quantities of chemical compounds are emitted into the troposphere. Alkanes, in general, and cycloalkanes are an important chemical class of hydrocarbons found in diesel, jet and gasoline, vehicle exhaust emissions, and ambient air in urban areas. In general, the primary atmospheric fate of organic compounds in the gas phase is the reaction with hydroxyl radicals (OH). The oxidation by Cl atoms has gained importance in the study of atmospheric reactions because they may exert some influence in the boundary layer, particularly in marine and coastal environments, and in the Arctic troposphere. The aim of this paper is to study of the atmospheric reactivity of methylcylohexanes with Cl atoms and OH radicals under atmospheric conditions (in air at room temperature and pressure). Relative kinetic techniques have been used to determine the rate coefficients for the reaction of Cl atoms and OH radicals with methylcyclohexane, cis-1,4-dimethylcyclohexane, trans-1,4-dimethylcyclohexane, and 1,3,5-trimethylcyclohexane at 298 ± 2K and 720 ± 5Torr of air by Fourier transform infrared) spectroscopy and gas chromatography-mass spectrometry (GC-MS) in two atmospheric simulation chambers. The products formed in the reaction under atmospheric conditions were investigated using a 200-L Teflon bag and employing the technique of solid-phase microextraction coupled to a GC-MS. The rate coefficients obtained for the reaction of Cl atoms with the studied compounds are the following ones (in units of 10(-10)cm(3)molecule(-1)s(-1)): (3.11 ± 0.16), (2.89 ± 0.16), (2.89 ± 0.26), and (2.61 ± 0.42), respectively. For the reactions with OH radicals the determined rate coefficients are (in units of 10(-11)cm(3)molecule(-1)s(-1)): (1.18 ± 0.12), (1.49 ± 0.16), (1.41 ± 0.15), and (1.77 ± 0.23), respectively. The reported error is twice the standard deviation. A detailed mechanism for ring-retaining product channels is proposed to justify the observed reaction products. The global tropospheric lifetimes estimated from the reported OH- and Cl-rate coefficients show that the main removal path for the investigated methylcyclohexanes is the reaction with OH radicals. But in marine environments, after sunrise, Cl reactions become more important in the tropospheric degradation. Thus, the estimated lifetimes range from 16 to 24h for the reactions of the OH radical (calculated with [OH] = 10(6)atomscm(-3)) and around 7-8h in the reactions with Cl atoms in marine environments (calculated with [Cl] = 1.3 × 10(5)atomscm(-3)). The reaction of Cl atoms and OH radicals and methylcylohexanes can proceed by H abstraction from the different positions.

The kinetics of the gas-phase reactions of OH radicals, NO3 radicals, and O3 with indan, indene, fluorene, and 9,10-dihydroanthracene have been studied at 297 ± 2 K and atmospheric pressure of air. The rate constants, or upper limits thereof, for the O3 reactions were (in cm3 molecule−1 s−1 units): indan, < 3 × 10−19; indene, (1.7 ± 0.5) × 10−16, fluorene, < 2 × 10−19; and 9,10-dihydroanthracene, (9.0 ± 2.0) × 10−19. Using a relative rate method, the rate constants for the OH radical and NO3 radical reactions, respectively, were (in cm3 molecule−1 s−1 units): indan, (1.9 ± 0.5) × 10−11 and (6.6 ± 2.0) × 10−15; indene, (7.8 ± 2.0) × 10−11 and (4.1 ± 1.5) × 10−12; fluorene, (1.6 ± 0.5) × 10−11 and (3.5 ± 1.2) × 10−14; and 9,10-dihydroanthracene, (2.3 ± 0.6) × 10−11 and (1.2 ± 0.4) × 10−12. These kinetic data were used to assess the relative contributions of the various reaction pathways. © 1997 John Wiley & Sons, Inc. Int J Chem Kinet 29: 299–309, 1997.

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Rate constants have been measured at 296 ± 2 K for the gas-phase reactions of camphor with OH radicals, NO3 radicals, and O3. Using relative rate methods, the rate constants for the OH radical and NO3 radical reactions were (4.6 ± 1.2) × 10−12 cm3 molecule−1 s−1 and <3 × 10−16 cm3 molecule−1 s−1, respectively, where the indicated error in the OH radical reaction rate constant includes the estimated overall uncertainty in the rate constant for the reference compound. An upper limit to the rate constant for the O3 reaction of <7 × 10−20 cm3 molecule−1 s−1 was also determined. The dominant tropospheric loss process for camphor is calculated to be by reaction with the OH radical. Acetone was identified and quantified as a product of the OH radical reaction by gas chromatography, with a formation yield of 0.29 ± 0.04. In situ atmospheric pressure ionization tandem mass spectrometry (API-MS) analyses indicated the formation of additional products of molecular weight 166 (dicarbonyl), 182 (hydroxydicarbonyl), 186, 187, 213 (carbonyl-nitrate), 229 (hydroxycarbonyl-nitrate), and 243. A reaction mechanism leading to the formation of acetone is presented, as are pathways for the formation of several of the additional products observed by API-MS. © 2000 John Wiley and Sons, Inc. Int J Chem Kinet 33: 56–63, 2001

Rate constants for the gas-phase reactions of OH radicals, NO3 radicals and O3 with the C7-carbonyl compounds 4-methylenehex-5-enal [CH2=CHC(=CH2)CH2CH2CHO], (3Z)- and (3E)-4-methylhexa-3,5-dienal [CH2=CHC(CH3)=CHCH2CHO] and 4-methylcyclohex-3-en-1-one, which are products of the atmospheric degradations of myrcene, Z- and E-ocimene and terpinolene, respectively, have been measured at 296 ± 2 K and atmospheric pressure of air using relative rate methods. The rate constants obtained (in cm3 molecule−1 s−1 units) were: for 4-methylenehex-5-enal, (1.55 ± 0.15) × 10−10, (4.75 ± 0.35) × 10−13 and (1.46 ± 0.12) × 10−17 for the OH radical, NO3 radical and O3 reactions, respectively; for (3Z)-4-methylhexa-3,5-dienal: (1.61 ± 0.35) × 10−10, (2.17 ± 0.30) × 10−12, and (4.13 ± 0.81) × 10−17 for the OH radical, NO3 radical and O3 reactions, respectively; for (3E)-4-methylhexa-3,5-dienal: (2.52 ± 0.65) × 10−10, (1.75 ± 0.27) × 10−12, and (5.36 ± 0.28) × 10−17 for the OH radical, NO3 radical and O3 reactions, respectively; and for 4-methylcyclohex-3-en-1-one: (1.10 ± 0.19) × 10−10, (1.81 ± 0.35) × 10−12, and (6.98 ± 0.40) × 10−17 for the OH radical, NO3 radical and O3 reactions, respectively. These carbonyl compounds are all reactive in the troposphere, with daytime reaction with the OH radical and nighttime reaction with the NO3 radical being predicted to dominate as loss processes and with estimated lifetimes of about an hour or less.