Laboratory studies of the ·OH‐initiated photooxidation of ethyl‐n‐butyl ether and di‐n‐butyl ether

Oxygenated compounds such as ethers and alcohols are used as gasoline additives and industrial solvents. However, despite their widespread use, the atmospheric reaction mechanisms of some of these compounds are unknown. This study examines the ^·OH‐initiated gas‐phase removal mechanisms of ethyl‐n‐butyl ether (ENBE) and di‐n‐butyl ether (DNBE) utilizing gas chromatography–mass spectrometry techniques. The primary products and molar yields from the hydroxyl‐radical–initiated photooxidation of ENBE in the presence of nitric oxide were acetaldehyde (0.173 ± 0.012), ethyl formate (0.219 ± 0.033), butyraldehyde (0.076 ± 0.004), butyl formate (0.241 ± 0.009), butyl acetate (0.032 ± 0.001), and ethyl butyrate (0.0044 ± 0.0006). From the calculated molar yields, approximately 45.5% of the reacted carbon were recovered. The primary products and molar yields from the DNBE and hydroxyl radical reaction in the presence of nitric oxide were propionaldehyde (0.379 ± 0.022), butyraldehyde (0.119 ± 0.003), butyl formate (0.410 ± 0.009), and butyl butyrate (0.019 ± 0.001). Approximately 47.7% of the reacted DNBE were recovered. The chemical mechanisms are presented to explain the formation of these products. In addition, the importance of the isomerization and nitrate/nitrite formation pathways in the reactions of large ethers are discussed. © 2001 John Wiley & Sons, Inc. Int J Chem Kinet 33: 328–341, 2001     

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

Using relative rate methods, rate constants for the gas‐phase 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 have been measured at 296 ± 2 K and atmospheric pressure of air. The rate constants obtained (in cm³ molecule⁻¹ s⁻¹ units) were: OH radical reactions, di‐n‐propyl ether, (2.18 ± 0.17) × 10⁻¹¹; di‐n‐propyl ether‐d₁₄, (1.13 ± 0.06) × 10⁻¹¹; di‐n‐butyl ether, (3.30 ± 0.25) × 10⁻¹¹; and di‐n‐butyl ether‐d₁₈, (1.49 ± 0.12) × 10⁻¹¹; Cl atom reactions, di‐n‐propyl ether, (3.83 ± 0.05) × 10⁻¹⁰; di‐n‐propyl ether‐d₁₄, (2.84 ± 0.31) × 10⁻¹⁰; di‐n‐butyl ether, (5.15 ± 0.05) × 10⁻¹⁰; and di‐n‐butyl ether‐d₁₈, (4.03 ± 0.06) × 10⁻¹⁰. The rate constants for the di‐n‐propyl ether and di‐n‐butyl ether reactions are in agreement with literature data, and the deuterium isotope effects are consistent with H‐atom abstraction being the rate‐determining steps for both the OH radical and Cl atom reactions. © 1999 John Wiley & Sons, Inc. Int J Chem Kinet 31: 425–431, 1999     

Products of the gas‐phase photooxidation reactions of 1‐propanol with OH radicals

An experimental investigation of the hydroxyl radical initiated gas‐phase photooxidation of 1‐propanol in the presence of NO was carried out in a reaction chamber using gas chromatography mass spectrometry. The products identified in the OH radical reactions of 1‐propanol were propionaldehyde and acetaldehyde, with corresponding formation yields of 0.719 ± 0.058 and 0.184 ± 0.030, respectively. Errors represent ±2σ. The experimental product yields were compared to predictions made using chemical mechanisms. © 1999 John Wiley & Sons, Inc. Int J Chem Kinet 31: 810–818, 1999     

Products of the gas‐phase reactions of the OH radical with n‐butyl methyl ether and 2‐isopropoxyethanol: Reactions of ROC(Ȯ) < radicals

The products of the gas‐phase reactions of the OH radical with n‐butyl methyl ether and 2‐isopropoxyethanol in the presence of NO have been investigated at 298 ± 2 K and 740 Torr total pressure of air by gas chromatography and in situ atmospheric pressure ionization tandem mass spectrometry. The products observed from n‐butyl methyl ether were methyl formate, propanal, butanal, methyl butyrate, and CH₃C(O)CH₂CH₂OCH₃ and/or CH₃CH₂C(O)CH₂OCH₃, with molar formation yields of 0.51 ± 0.11, 0.43 ± 0.06, 0.045 ± 0.010, ∼0.016, and 0.19 ± 0.04, respectively. Additional products of molecular weight 118, 149 and 165 were observed by API‐MS/MS analyses, with those of molecular weight 149 and 165 being identified as organic nitrates. The products observed and quantified from 2‐isopropoxyethanol were isopropyl formate and 2‐hydroxyethyl acetate, with molar formation yields of 0.57 ± 0.05 and 0.44 ± 0.05, respectively. For both compounds, the majority of the reaction products and reaction pathways are accounted for, and detailed reaction mechanisms are presented. The results of this product study are combined with previous literature product data to investigate the tropospheric reactions of R₁R₂C(Ȯ)OR radicals formed from ethers and glycol ethers, leading to a revised estimation method for the calculation of reaction rates of alkoxy radicals. © 1999 John Wiley & Sons, Inc. Int J Chem Kinet 31: 501–513, 1999     

Rate constants for the gas‐phase reactions of Cl atoms with a series of ethers

The laser photolysis–resonance fluorescence technique has been used to determine the absolute rate coefficient for the Cl atom reaction with a series of ethers, at room temperature (298 ± 2) K and in the pressure range 15–60 Torr. The rate coefficients obtained (in units of cm³ molecule⁻¹ s⁻¹) are dimethyl ether (1.3 ± 0.2) × 10⁻¹⁰, diethyl ether (2.5 ± 0.3) × 10⁻¹⁰, di‐n‐propyl ether (3.6 ± 0.4) × 10⁻¹⁰, di‐n‐butyl ether (4.5 ± 0.5) × 10⁻¹⁰, di‐isopropyl ether (1.6 ± 0.2) × 10⁻¹⁰, methyl tert‐butyl ether (1.4 ± 0.2) × 10⁻¹⁰, and ethyl tert‐butyl ether (1.5 ± 0.2) × 10⁻¹⁰. The results are discussed in terms of structure–reactivity relationship. © 2000 John Wiley & Sons, Inc. Int J Chem Kinet 32: 105–110, 2000     

Kinetics and Products of the Reactions of Ethyl and n‐Propyl Nitrates with OH Radicals

The kinetics of the reactions of ethyl (1) and n‐propyl (2) nitrates with OH radicals has been studied using a low‐pressure flow tube reactor combined with a quadrupole mass spectrometer. The rate constants of the title reactions were determined under pseudo–first‐order conditions from kinetics of OH consumption in high excess of nitrates. The overall rate constants, k₁ = 1.14 × 10^?13 (T/298)^2.45 exp(193/T) and k₂ = 3.00 × 10^?13 (T/298)^2.50 exp(205/T) cm³ molecule^?1 s^?1 (with conservative 15% uncertainty), were determined at a total pressure of 1 Torr of helium over the temperature range (248–500) and (263–500) K, respectively. The yields of the carbonyl compounds, acetaldehyde and propanal, resulting from the abstraction by OH of an α‐hydrogen atom in ethyl and n‐propyl nitrates, followed by α‐substituted alkyl radical decomposition, were determined at T = 300 K to be 0.77 ± 0.12 and 0.22 ± 0.04, respectively.     

Kinetics and mechanism of the atmospheric oxidation of tertiary amyl methyl ether

Tertiary-amyl methyl ether (TAME) is proposed for use as an additive to increase the oxygen content of gasoline as stipulated in the 1990 Clean Air Amendments. The present experiments have been performed to examine the kinetics and mechanisms of the atmospheric removal of TAME. The kinetics of the reaction of OH with TAME was examined by using a relative rate technique in which photolysis of methyl nitrite or nitrous acid was used as the source of OH. The OH rate constant for TAME and two major products (t-amyl formate and methyl acetate) were measured and yields for ten products were determined as primary products from the reaction. Values determined for the rate constants for the reaction with OH were 5.48 × 10^?12 (TAME), 1.75 × 10^?12 (t-amyl formate), and 3.85 × 10^?13 cm³ molec^?1 s^?1 (methyl acetate) at 298 ± 2 K. The primary products (with corrected yields where required) from the OH + TAME that have been observed include (1) t-amyl formate (0.366), methyl acetate (0.349), acetaldehyde (0.43, corrected), acetone (0.036), formaldehyde (0.549), t-amyl alcohol (0.026), 3-methyoxy-3-methyl-butanal (0.044, corrected), t-amyloxy methyl nitrate (0.029), 3-methyoxy-3-methyl-2-butyl nitrate (0.010), and 2-methoxy-2-methyl butyl nitrate (0.004). Mechanisms leading to these products involve OH abstraction from each of the four different hydrogen atoms of TAME. © 1995 John Wiley & Sons, Inc.     

The production of organic nitrates from atmospheric oxidation of ethers and glycol ethers

The production of organic nitrates from OH reaction (in the presence of NO) with methoxy propane, 1‐methoxy‐2‐propanol, ethoxy butane, and 2‐butoxyethanol was studied. The measured total organic nitrate yields were 1.8 (±0.4)%, 0.98 (±0.2)%, 7.7 (±2)%, and 9.6 (±1)%, respectively. The total organic nitrate yield for methoxypropane is 26% of that (7.0%) for n‐butane. The organic nitrate yield for ethoxy butane is 55% of that (14%) for n‐hexane. The peroxy radicals produced from OH reaction with the methylene groups α to the ether linkage have an organic nitrate branching ratio (k_3b/k₃) value ∼50% of those in analogous n‐alkanes. On the other hand, k_3b/k₃ values for peroxy radical functional groups not adjacent to the ether linkage (in γ and δ positions) are on average 1.7 times greater than for the analogous n‐alkyl peroxy radicals. The organic nitrate formation yield for 1‐methoxy‐2‐propanol is almost half that of methoxy propane, while for 2‐butoxyethanol it is 21% greater than that of butoxyethane. Our data lead us to the conclusion that the ether linkage imparts an inductive effect that decreases the value of k_3b/k₃ for peroxy radicals adjacent to it, yet has a stabilizing effect, from the additional vibrational modes for those peroxy radicals not adjacent to it, increasing their k_3b/k₃ values. The effect of both the  O and OH groups in these molecules and the importance of their position relative to the peroxy group are discussed in this paper. © 2005 Wiley Periodicals, Inc. Int J Chem Kinet 37: 686–699, 2005     

Kinetics and mechanism of the atmospheric oxidation of Ethyl tertiary butyl ether

Ethyl tertiary butyl ether (ETBE) is being proposed as an additive for use in reformulated gasolines. In this study, experiments were performed to examine the kinetics and mechanism of the atmospheric removal of ETBE. The kinetics of the reaction of ETBE with OH radicals were examined by using a relative rate technique with the photolysis of methyl nitrite to generate OH radicals. With n-hexane as the reference compound, a value of (9.73 ± 0.33) × 10^?12 cm³ molecule^?1 s^?1 was obtained for the rate constant. The OH rate constant for t-butyl acetate, a product of the oxidation of ETBE, was (4.4 ± 0.4) × 10^?13 cm³ molecule^?1 s^?1 at 298 K. The primary products and molar yields for the OH reaction with ETBE in the presence of NO_x were t-butyl formate (0.64 ± 0.03), t-butyl acetate (0.13 ± 0.01), ethyl acetate (0.043 ± 0.003), acetaldehyde (0.16 ± 0.01), acetone (0.019 ± 0.002), and formaldehyde (0.53 ± 0.04). Under the described reaction conditions, the formation of t-butyl nitrite was also observed. From these molar yields, approximately 98% of the reacted ETBE could be accounted for by paths leading to these products. Chemical mechanisms to explain the formation of these products are presented.     

Atmospheric chemistry of isopropyl formate and tert‐butyl formate

Formates are produced in the atmosphere as a result of the oxidation of a number of species, notably dialkyl ethers and vinyl ethers. This work describes experiments to define the oxidation mechanisms of isopropyl formate, HC(O)OCH(CH₃)₂, and tert‐butyl formate, HC(O)OC(CH₃)₃. Product distributions are reported from both Cl‐ and OH‐initiated oxidation, and reaction mechanisms are proposed to account for the observed products. The proposed mechanisms include examples of the α‐ester rearrangement reaction, novel isomerization pathways, and chemically activated intermediates. The atmospheric oxidation of isopropyl formate by OH radicals gives the following products (molar yields): acetic formic anhydride (43%), acetone (43%), and HCOOH (15–20%). The OH radical initiated oxidation of tert‐butyl formate gives acetone, formaldehyde, and CO₂ as major products. IR absorption cross sections were derived for two acylperoxy nitrates derived from the title compounds. Rate coefficients are derived for the kinetics of the reactions of isopropyl formate with OH (2.4 ± 0.6) × 10^?12, and with Cl (1.75 ± 0.35) × 10^?11, and for tert‐butyl formate with Cl (1.45 ± 0.30) × 10^?11 cm³ molecule^?1 s^?1. Simple group additivity rules fail to explain the observed distribution of sites of H‐atom abstraction for simple formates. © 2010 Wiley Periodicals, Inc. Int J Chem Kinet 42: 479–498, 2010     

Di­propyl 3,6‐di­phenyl‐1,2‐di­hydro‐1,2,4,5‐tetrazine‐1,2‐di­carboxyl­ate

The title compound, C₂₂H₂₄N₄O₄, was prepared from propyl chloro­formate and 3,6‐di­phenyl‐1,2‐di­hydro‐s‐tetrazine. This reaction yields the title compound rather than di­propyl 3,6‐di­phenyl‐1,4‐di­hydro‐s‐tetrazine‐1,4‐di­carboxyl­ate. The 2,3‐di­aza­buta­diene group in the central six‐membered ring is not planar; the C=N double‐bond length is 1.285 (2) Å, and the average N—N single‐bond length is 1.401 (3) Å, indicating a lack of conjugation. The ring has a twist conformation, in which adjacent N atoms lie 0.3268 (17) Å from the plane of the ring. The mol­ecule has twofold crystallographic symmetry.     

Products of the gas-phase reaction of methyl tert-butyl ether with the OH radical in the presence of NOx

The products of the reaction of the hydroxyl (OH) radical with methyl tert-butyl ether (MTBE) in NO_x-air systems were identified and measured by Fourier transform infrared absorption spectroscopy and gas chromatography. The products observed, and their yields, were as follows: t-butyl formate, 76 ± 7%; formaldehyde, 37%; methyl acetate, 17 ± 2%, and acetone, 2.1 ± 0.9%, where the stated error limits represent both random (two standard deviations) and estimated systematic uncertainties. These products account for ca. 95% of the MTBE carbon reacted. Infrared absorption bands which may be due to small amounts of organic nitrate formation were observed, but organic nitrate yields could not be quantified. These data allow a chemical mechanism for the reaction of MTBE with the OH radical in the presence of NO_x to be formulated.     

The production of organic nitrates from various anthropogenic volatile organic compounds

Production of organic nitrates from OH reaction with cyclohexane, cyclohexene, n‐butane, 1‐bromopropane, and p‐xylene in the presence of NO was studied. The total organic nitrate yields for cyclohexane and n‐butane were determined to be 17 ± 4 and 7 ± 2% respectively, which is in good agreement with previous determinations. Total yields for cyclohexene, 1‐bromopropane, and p‐xylene were 2.5 ± 0.5, 1.2 ± 0.3, and 3.2 ± 0.7 respectively. The yield for cyclohexene was five times smaller than that for cyclohexane. The 1‐bromopropane yield is three times smaller that that for n‐propane, but similar to that for propene, indicating that the effect of Br substitution in the reactant may be similar to that for OH substitution. The only nitrooxy product detected for p‐xylene was 4‐methylbenzylnitrate, which was formed following H abstraction from either methyl group. No organic nitrate was detected for peroxy radicals produced from OH addition to the ring, which accounts for 90% of the OH oxidation of p‐xylene. The calculated k_3b/k₃ value for p‐methyl benzyl peroxy radicals (0.32) was slightly smaller than for n‐octyl peroxy radicals (0.39). These data imply that substituent inductive effects impact the k_3b/k₃ ratios. We found no significant difference in the k_3b/k₃ ratios for primary vs. secondary peroxy radicals of the same carbon chain. © 2005 Wiley Periodicals, Inc. Int J Chem Kinet 37: 675–685, 2005     

Formation of alkyl nitrates from the reaction of branched and cyclic alkyl peroxy radicals with NO

The yields of C₅ and C₆ alkyl nitrates from neopentane, 2-methylbutane, 2-methylpentane, 3-methylpentane, and cyclohexane have been measured in irradiated CH₃ONONO-alkane-air mixtures at 298 ± 2 K and 735-torr total pressure. Additionally, OH radical rate constants for neopentyl nitrate, 3-nitro-2-methylbutane, 2-nitro-2-methylpentane, 2-nitro-3-methylpentane, and cyclohexyl nitrate, relative to that for n-butane, have been determined at 298 ± 2 K. Using a rate constant for the reaction of OH radicals with n-butane of 2.58 × 10^?12 cm³ molecule^?1 s^?1, these OH radical rate constants are (in units of 10^?12 cm³ molecule^?1 s^?1): neopentyl nitrate, 0.87 ± 0.21; cyclohexyl nitrate, 3.35 ± 0.36; 3-nitro-2-methylbutane, 1.75 ± 0.06; 2-nitro-2-methylpentane, 1.75 ± 0.22; and 2-nitro-3-methylpentane, 3.07 ± 0.08. After accounting for consumption of the alkyl nitrates by OH radical reaction and for the yields of the individual alkyl peroxy radicals formed in the reaction of OH radicals with the alkanes studied, the alkyl nitrate yields (which reflect the fraction of the individual RO₂ radicals reacting with NO to form RONO₂) determined were: neopentyl nitrate, 0.0513 ± 0.0053; cyclohexyl nitrate, 0.160 ± 0.015; 3-nitro-2-methylbutane, 0.109 ± 0.003; 2-nitro-2methylbutane, 0.0533 ± 0.0022; 2-nitro-2-methylpentane, 0.0350 ± 0.0096; 3- + 4-nitro-2-methylpentane, 0.165 ± 0.016; and 2-nitro-3-methylpentane, 0.140 ± 0.014. These results are discussed and compared with previous literature values for the alkyl nitrates formed from primary and secondary alkyl peroxy radicals generated from a series of n-alkanes.     

The hydroxyl radical reaction rate constant and atmospheric transformation products of 2‐propoxyethanol

The relative rate technique has been used to measure the hydroxyl radical (OH) reaction rate constant of 2‐propoxyethanol (2PEOH, CH₃CH₂CH₂OCH₂CH₂(OH)). 2PEOH reacts with OH with a bimolecular rate constant of (21.4 ± 6.0) × 10⁻¹² cm³molecule⁻¹s⁻¹ at 297 ± 3 K and 1 atm total pressure, which is a little larger than previously reported [1]. Assuming an average OH concentration of 1 × 10⁶ molecules cm⁻³, an atmospheric lifetime of 13 h is calculated for 2PEOH. In order to more clearly define this hydroxy ether's atmospheric reaction mechanism, an investigation into the OH + 2PEOH reaction products was also conducted. The OH + 2PEOH reaction products and yields observed were: propyl formate (PF, 47 ± 2%, CH₃CH₂CH₂OC(O)H), 2 propoxyethanal (CH₃CH₂CH₂OCH₂C(O)H 15 ± 1%), and 2‐ethyl‐1,3‐dioxolane (5.4 ± 0.4%). The 2PEOH reaction mechanism is discussed in light of current understanding of oxygenated hydrocarbon atmospheric chemistry. The findings reported here can be related to other structurally similar alcohols and may impact regulatory tools such as ground‐level ozone‐forming potential calculations (incremental reactivity) [2]. © 1999 John Wiley & Sons, Inc. Int J Chem Kinet 31: 315–322, 1999     

Bildung und Molekülstruktur von [{(CH3)3Si}3C(nC3H7)In(μ‐OH)]3

Formation and Structure of [{(CH₃)₃Si}₃C(ⁿC₃H₇)In(μ‐OH)]₃ The title compound has been prepared in low yield by the reaction of [(THF)₂LiC(SiMe₃)₃]₂with humid di(n‐propyl) indium bromide and purified by sublimation at 110–115 °C/10^–3 hPa. This organo indium hydroxo compound forms a trimer via In–OH–In bridges and crystallizes in the triclinic space group P 1 with two trimers and one toluene molecule per unitcell. The In₃O₃ heterocycle has chair‐, the n‐propyl ligand has trans‐conformation, respectively.     

The photooxidation of methyl tertiary butyl ether

Methyl tertiary butyl ether (MTBE) has been proposed and is being used as an additive to increase the octane of gasoline without the use of tetraethyl lead and alkylbenzenes. The present experiments have been performed to examine the kinetics and mechanisms of the atmospheric removal of MTBE. The kinetics of the reaction of OH with MTBE was examined by using a relative rate technique in which photolysis of methyl nitrite was used as the source of OH. With n-butane as the reference compound a value of (2.99 ± 0.12) × 10^?12 cm³ molecule^?1 s^?1 at a temperature of 298 K was obtained for the rate constant. The products (and product yields) for the OH reaction with MTBE in the presence of NO_x were also determined and found to be t-butyl formate (0.68 ± 0.05), methyl acetate (0.14 ± 0.02), acetone (0.026 ± 0.003), t-butanol (0.062 ± 0.009), and formaldehyde (0.48 ± 0.05) in mols/mol MTBE converted. The OH rate constant for the major product formed, t-butyl formate was also measured and found to be (7.37 ± 0.05) × 10^?13 cm³ molecule^?1 s^?1. Mechanisms to rationalize the formation of the products are presented.     

Rate constants of the gas‐phase reactions of OH radicals with trans‐2‐hexenal,trans‐2‐octenal,and trans‐2‐nonenal

The rate constants of the gas‐phase reaction of OH radicals with trans‐2‐hexenal, trans‐2‐octenal, and trans‐2‐nonenal were determined at 298 ± 2 K and atmospheric pressure using the relative rate technique. Two reference compounds were selected for each rate constant determination. The relative rates of OH + trans‐2‐hexenal versus OH + 2‐methyl‐2‐butene and β‐pinene were 0.452 ± 0.054 and 0.530 ± 0.036, respectively. These results yielded an average rate constant for OH + trans‐2‐hexenal of (39.3 ± 1.7) × 10^?12 cm³ molecule^?1 s^?1. The relative rates of OH+trans‐2‐octenal versus the OH reaction with butanal and β‐pinene were 1.65 ± 0.08 and 0.527 ± 0.032, yielding an average rate constant for OH + trans‐2‐octenal of (40.5 ± 2.5) × 10^?12 cm³ molecule^?1 s^?1. The relative rates of OH+trans‐2‐nonenal versus OH+ butanal and OH + trans‐2‐hexenal were 1.77 ± 0.08 and 1.09 ± 0.06, resulting in an average rate constant for OH + trans‐2‐nonenal of (43.5 ± 3.0) × 10^?12 cm³ molecule^?1 s^?1. In all cases, the errors represent 2σ (95% confidential level) and the calculated rate constants do not include the error associated with the rate constant of the OH reaction with the reference compounds. The rate constants for the hydroxyl radical reactions of a series of trans‐2‐aldehydes were compared with the values estimated using the structure activity relationship. © 2009 Wiley Periodicals, Inc. Int J Chem Kinet 41: 483–489, 2009     

Kinetics and mechanism of the reactions of n‐butanal and n‐pentanal with chlorine atoms

The kinetics and mechanism of the reaction of chlorine atoms with n‐butanal and n‐pentanal have been investigated in a 142‐L reaction cell coupled to a Fourier transform infrared (FTIR) spectrometer at 298 ± 2 K and at 800 ± 3 Torr. The rate coefficients for Cl + n‐butanal and Cl + n‐pentanal were measured using the relative rate technique with isopropanol and ethene as the reference compounds. The yield of acyl radicals was determined by measuring yields of acid chloride and carbon monoxide products from the reaction of Cl + aldehyde in the absence of oxygen. The rate coefficients for Cl + n‐butanal and Cl + n‐pentanal are (1.63 ± 0.59) × 10^?10 cm³ molecule^?1 s^{? 1} and (2.37 ± 0.82) × 10^?10 cm³ molecule^?1 s^?1, respectively. The yields of acyl radicals from the reactions are 0.66 ± 0.04 for n‐butanal and 0.45 ± 0.04 for n‐pentanal. Under ambient conditions, the acyl radicals generated will react almost exclusively with oxygen. Mechanistic implications of these measurements are discussed. © 2008 Wiley Periodicals, Inc. Int J Chem Kinet 41: 133–141, 2009     

Extent of H-atom abstraction from the reaction of the OH radical with 1-butene under atmospheric conditions

Products of the reaction of OH radicals with 1-butene have been investigated in the presence of NO in one atmosphere of air at room temperature using gas chromatography and in situ long pathlength Fourier transform infrared absorption spectroscopy. The major product observed was propionaldehyde, with a formation yield (after allowing for its subsequent loss processes) of 0.94 ± 0.12. Minor yields of organic nitrates (RONO₂) and of peroxypropionyl nitrate, a secondary product arising from propionaldehyde, were also observed. However, none of the products expected from the reactions subsequent to H-atom abstraction from 1-butene by OH radicals were observed, allowing an upper limit of 10% for this process to be derived. These data are compared with the available literature results and the implications are discussed.