Kinetics and mechanism of the gas phase reaction of chlorine atoms with i-propanol

Yamanaka, T.; Kawasaki, Masahiro; Hurley, M. D.; Wallington, Timothy J.; Schneider, William F.; Bruce, J. Malcolm

doi:10.1039/b702933k

Cited by 16 publications

(15 citation statements)

References 22 publications

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“…In the present experiments with 110 mTorr of Cl 2 in 700 Torr of nitrogen, reactions − will be the dominant fate of the radicals produced by reaction . It has been observed in previous experiments using the chamber at Ford that α-chloro-alcohols such as CH 2 ClOH, CHCl 2 OH, CCl 3 OH, CH 3 CHClOH, CH 3 CClOHCH 3 , and CH 3 (CH 2 ) 2 CHClOH decompose heterogeneously in the chamber via elimination of HCl to give the corresponding carbonyl compounds on a time scale typically of a few minutes. Similar behavior was observed in the present study with the formation of i -butyraldehyde (complete within 5−10 min) on allowing reaction mixtures to stand in the dark.…”

Section: Resultsmentioning

confidence: 99%

Atmospheric Chemistry of i-Butanol

2010

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Smog chamber/FTIR techniques were used to determine rate constants of k(Cl + i-butanol) = (2.06 ± 0.40) × 10(-10), k(Cl + i-butyraldehyde) = (1.37 ± 0.08) × 10(-10), and k(OH + i-butanol) = (1.14 ± 0.17) × 10(-11) cm(3) molecule(-1) s(-1) in 700 Torr of N(2)/O(2) diluent at 296 ± 2K. The UV irradiation of i-butanol/Cl(2)/N(2) mixtures gave i-butyraldehyde in a molar yield of 53 ± 3%. The chlorine atom initiated oxidation of i-butanol in the absence of NO gave i-butyraldehyde in a molar yield of 48 ± 3%. The chlorine atom initiated oxidation of i-butanol in the presence of NO gave (molar yields): i-butyraldehyde (46 ± 3%), acetone (35 ± 3%), and formaldehyde (49 ± 3%). The OH radical initiated oxidation of i-butanol in the presence of NO gave acetone in a yield of 61 ± 4%. The reaction of chlorine atoms with i-butanol proceeds 51 ± 5% via attack on the α-position to give an α-hydroxy alkyl radical that reacts with O(2) to give i-butyraldehyde. The atmospheric fate of (CH(3))(2)C(O)CH(2)OH alkoxy radicals is decomposition to acetone and CH(2)OH radicals. The atmospheric fate of OCH(2)(CH(3))CHCH(2)OH alkoxy radicals is decomposition to formaldehyde and CH(3)CHCH(2)OH radicals. The results are consistent with, and serve to validate, the mechanism that has been assumed in the estimation of the photochemical ozone creation potential of i-butanol.

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Section: Resultsmentioning

confidence: 99%

Atmospheric Chemistry of i-Butanol

2010

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“…In the present experiments with 101−112 mTorr of Cl 2 in 700 Torr of nitrogen, it is expected that reactions − will be the dominant fate of the radicals produced by reaction of chlorine atoms with n -butanol. α-Chloro-alcohols such as CH 2 ClOH, CHCl 2 OH, CCl 3 OH, CH 3 CHClOH, and CH 3 CClOHCH 3 decompose heterogeneously in the chamber via elimination of HCl − to give the corresponding carbonyl compounds on a time scale typically of a few minutes. The decomposition of CH 3 CH 2 CH 2 CHClOH was complete within a few minutes and gave butyraldehyde, which provides a marker for reaction .…”

Section: Resultsmentioning

confidence: 99%

Atmospheric Chemistry ofn-Butanol: Kinetics, Mechanisms, and Products of Cl Atom and OH Radical Initiated Oxidation in the Presence and Absence of NO_x.

et al. 2009

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Smog chamber/FTIR techniques were used to determine rate constants of k(Cl+n-butanol) = (2.21 +/- 0.38) x 10(-10) and k(OH+n-butanol) = (8.86 +/- 0.85) x 10(-12) cm(3) molecule(-1) s(-1) in 700 Torr of N(2)/O(2) diluent at 296 +/- 2K. The sole primary product identified from the Cl atom initiated oxidation of n-butanol in the absence of NO was butyraldehyde (38 +/- 2%, molar yield). The primary products of the Cl atom initiated oxidation of n-butanol in the presence of NO were (molar yield) butyraldehyde (38 +/- 2%), propionaldehyde (23 +/- 3%), acetaldehyde (12 +/- 4%), and formaldehyde (33 +/- 3%). The substantially lower yields of propionaldehyde, acetaldehyde, and formaldehyde as primary products in experiments conducted in the absence of NO suggests that chemical activation is important in the atmospheric chemistry of CH(3)CH(2)CH(O)CH(2)OH and CH(3)CH(O)CH(2)CH(2)OH alkoxy radicals. The primary products of the OH radical initiated oxidation of n-butanol in the presence of NO were (molar yields) butyraldehyde (44 +/- 4%), propionaldehyde (19 +/- 2%), and acetaldehyde (12 +/- 3%). In all cases, the product yields were independent of oxygen concentration over the partial pressure range of 10-600 Torr. The yields of propionaldehyde, acetaldehyde, and formaldehyde quoted above were not corrected for secondary formation via oxidation of higher aldehydes and should be treated as upper limits. The reactions of Cl atoms and OH radicals with n-butanol proceed 38 +/- 2 and 44 +/- 4%, respectively, via attack on the alpha-position to give an alpha-hydroxy alkyl radical which reacts with O(2) to give butyraldehyde. The results are discussed with respect to the atmospheric chemistry of n-butanol.

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“…Within MCM v3.2, Cl kinetics and mechanisms are included only for alkanes. We added Cl kinetics and degradation mechanisms for methanol, ethanol, isopropanol, formaldehyde, acetone, ethyne, ethene, and toluene (Taatjes et al, 1999;Atkinson et al, 2006;Yamanaka et al, 2007;Kaiser and Wallington, 2010;Zhou et al, 2005;Yarwood et al, 1991), with the reaction rates given in Table S1. Concentrations for all alkanes and alcohols that were measured at the CalNex ground site were explicitly included (ethane, propane, n-butane, i-butane, n-pentane, i-pentane, hexane, nonane, decane, undecane, methanol, ethanol, and isopropanol).…”

Section: Modelingmentioning

confidence: 99%

“…The chemistry of Cl with alcohols was included with little modification of the model, because their reactions with Cl are well characterized and proceed by hydrogen abstraction leading to a radical species that is already explicitly included in the model. Radical yields for reaction of Cl with alcohols were taken from Taatjes et al (1999) and Yamanaka et al (2007). Other classes of compounds have complex reactions with Cl that are poorly understood.…”

Section: Modelingmentioning

confidence: 99%

Chlorine as a primary radical: evaluation of methods to understand its role in initiation of oxidative cycles

et al. 2014

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Abstract. The role of chlorine atoms (Cl) in atmospheric oxidation has been traditionally thought to be limited to the marine boundary layer, where they are produced through heterogeneous reactions involving sea salt. However, recent observation of photolytic Cl precursors (ClNO2 and Cl2) formed from anthropogenic pollution has expanded the potential importance of Cl to include coastal and continental urban areas. Measurements of ClNO2 in Los Angeles during CalNex (California Nexus – Research at the Nexus of Air Quality and Climate Change) showed it to be an important primary (first generation) radical source. Evolution of ratios of volatile organic compounds (VOCs) has been proposed as a method to quantify Cl oxidation, but we find no evidence from this approach for a significant role of Cl oxidation in Los Angeles. We use a box model with the Master Chemical Mechanism (MCM v3.2) chemistry scheme, constrained by observations in Los Angeles, to examine the Cl sensitivity of commonly used VOC ratios as a function of NOx and secondary radical production. Model results indicate VOC tracer ratios could not detect the influence of Cl unless the ratio of [OH] to [Cl] was less than 200 for at least a day. However, the model results also show that secondary (second generation) OH production resulting from Cl oxidation of VOCs is strongly influenced by NOx, and that this effect obscures the importance of Cl as a primary oxidant. Calculated concentrations of Cl showed a maximum in mid-morning due to a photolytic source from ClNO2 and loss primarily to reactions with VOCs. The [OH] to [Cl] ratio was below 200 for approximately 3 h in the morning, but Cl oxidation was not evident from the measured ratios of VOCs. Instead, model simulations show that secondary OH production causes VOC ratio evolution to follow that expected for OH oxidation, despite the significant input of primary Cl from ClNO2 photolysis in the morning. Even though OH is by far the dominant oxidant in Los Angeles, Cl atoms do play an important role in photochemistry there, constituting 9% of the primary radical source. Furthermore, Cl–VOC reactivity differs from that of OH, being more than an order of magnitude larger and dominated by VOCs, such as alkanes, that are less reactive toward OH. Primary Cl is also slightly more effective as a radical source than primary OH due to its greater propensity to initiate radical propagation chains via VOC reactions relative to chain termination via reaction with nitrogen oxides.

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Kinetics and mechanism of the gas phase reaction of chlorine atoms with i-propanol

Cited by 16 publications

References 22 publications

Atmospheric Chemistry of i-Butanol

Atmospheric Chemistry of i-Butanol

Atmospheric Chemistry ofn-Butanol: Kinetics, Mechanisms, and Products of Cl Atom and OH Radical Initiated Oxidation in the Presence and Absence of NO_x.

Chlorine as a primary radical: evaluation of methods to understand its role in initiation of oxidative cycles

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Kinetics and mechanism of the gas phase reaction of chlorine atoms with i-propanol

Cited by 16 publications

References 22 publications

Atmospheric Chemistry of i-Butanol

Atmospheric Chemistry of i-Butanol

Atmospheric Chemistry ofn-Butanol: Kinetics, Mechanisms, and Products of Cl Atom and OH Radical Initiated Oxidation in the Presence and Absence of NOx.

Chlorine as a primary radical: evaluation of methods to understand its role in initiation of oxidative cycles

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Atmospheric Chemistry ofn-Butanol: Kinetics, Mechanisms, and Products of Cl Atom and OH Radical Initiated Oxidation in the Presence and Absence of NO_x.