scholarly journals Atmospheric sink of methyl chlorodifluoroacetate and ethyl chlorodifluoroacetate: temperature dependent rate coefficients, product distribution of their reactions with Cl atoms and CF2ClC(O)OH formation

RSC Advances ◽  
2016 ◽  
Vol 6 (57) ◽  
pp. 51834-51844
Author(s):  
María B. Blanco ◽  
Ian Barnes ◽  
Peter Wiesen ◽  
Mariano A. Teruel
Keyword(s):  
Relative Rate ◽  
Product Distribution ◽  
Rate Coefficients ◽  
Gas Phase Reactions ◽  
Temperature Dependent ◽  
Dependent Rate ◽  
P Rate ◽  
Distribution Studies ◽  
First Time ◽  
Cl Atoms

Rate coefficients as a function of temperature and product distribution studies have been performed for the first time for the gas-phase reactions of chlorine atoms with methyl chlorodifluoracetate (k1) and ethyl chlorodifluoroacetate (k2) using the relative rate technique.

scholarly journals Experimental and computational kinetics investigations for the reactions of Cl atoms with series of unsaturated ketones in gas phase

2017 ◽  
Author(s):  
Siripina Vijayakumar ◽  
Avinash Kumar ◽  
Balla Rajakuma
Keyword(s):  
Gas Phase ◽  
State Theory ◽  
Rate Coefficients ◽  
Gas Phase Reactions ◽  
Temperature Dependent ◽  
Unsaturated Ketones ◽  
Temperature Range ◽  
Computational Calculations ◽  
Temperature Rate ◽  
Cl Atoms

Abstract. Temperature dependent rate coefficients for the gas phase reactions of Cl atoms with 4-hexen-3-one and 5-hexen-2-one were measured over the temperature range of 298–363 K relative to 1-pentene, 1,3-butadiene and isoprene. Gas Chromatography (GC) was used to measure the concentrations of the organics. The derived temperature dependent Arrhenius expressions are k4-hexen-3-one+Cl (298–363 K) = (2.82 ± 1.76)×10−12exp [(1556 ± 438)/T] cm3 molecule−1 s−1 and k5-hexen-2-one+Cl (298–363 K) = (4.6 ± 2.4)×10−11exp[(646 ± 171)/T] cm3 molecule−1 s−1. The corresponding room temperature rate coefficients are (5.54 ± 0.41)×10−10 cm3 molecule−1 s−1 and (4.00 ± 0.37)×10−10 cm3 molecule−1 s−1 for the reactions of Cl atoms with 4-hexen-3-one and 5-hexen-2-one respectively. To understand the mechanism of Cl atom reactions with unsaturated ketones, computational calculations were performed for the reactions of Cl atoms with 4-hexen-3-one, 5-hexen-2-one and 3-penten-2-one over the temperature range of 275–400 K using Canonical Variational Transition state theory (CVT) with Small Curvature Tunneling (SCT) in combination with CCSD(T)/6-31+G(d, p)//MP2/6-311++G(d, p) level of theory. Atmospheric implications, reaction mechanism and feasibility of the title reactions are discussed in this manuscript.

Gas-phase ozonolysis of β-ocimene: Temperature dependent rate coefficients and product distribution

2016 ◽  
Vol 147 ◽  
pp. 46-54 ◽  
Author(s):  
Elizabeth Gaona-Colmán ◽  
María B. Blanco ◽  
Ian Barnes ◽  
Mariano A. Teruel
Keyword(s):  
Gas Phase ◽  
Product Distribution ◽  
Rate Coefficients ◽  
Temperature Dependent ◽  
Dependent Rate

scholarly journals Kinetics of the gas-phase reactions of OH radicals with alkanes and cycloalkanes

2003 ◽  
Vol 3 (6) ◽  
pp. 2233-2307 ◽  
Author(s):  
R. Atkinson
Keyword(s):  
Gas Phase ◽  
Rate Constants ◽  
Relative Rate ◽  
Oh Radicals ◽  
Gas Phase Reactions ◽  
Temperature Dependent ◽  
Temperature Range ◽  
Dependent Rate ◽  
Temperature Ranges ◽  
Kinetics Of

Abstract. The available database concerning rate constants for gas-phase reactions of the hydroxyl (OH) radical with alkanes through early 2003 is presented over the entire temperature range for which measurements have been made (~180-2000 K). Measurements made using relative rate methods are re-evaluated using recent rate data for the reference compound (generally recommendations from this review). In general, whenever more than one study has been carried out over an overlapping temperature range, recommended rate constants or temperature-dependent rate expressions are presented. The recommended 298 K rate constants, temperature-dependent parameters, and temperature ranges over which these recommendations are applicable are listed in Table 1.

scholarly journals Kinetics of the gas-phase reactions of OH radicals with alkanes and cycloalkanes

2003 ◽  
Vol 3 (4) ◽  
pp. 4183-4358 ◽  
Author(s):  
R. Atkinson
Keyword(s):  
Gas Phase ◽  
Rate Constants ◽  
Relative Rate ◽  
Oh Radicals ◽  
Reference Compound ◽  
Gas Phase Reactions ◽  
Temperature Dependent ◽  
Temperature Range ◽  
Dependent Rate ◽  
Kinetics Of

Abstract. The available database concerning rate constants for gas-phase reactions of the hydroxyl (OH) radical with alkanes through early 2003 is presented ove the entire temperature range for which measurements have been made (~180–2000 K). Measurements made using relative rate methods are re-evaluated using recent rate data for the reference compound (generally recommendations from this review). In general, whenever more than one study has been carried out over an overlapping temperature range, recommended rate constants or temperature-dependent rate expressions are presented.

scholarly journals Degradation of a series of fluorinated acrylates and methacrylates initiated by OH radicals at different temperatures

RSC Advances ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 4264-4273
Author(s):  
P. Lugo García ◽  
C. B. Rivela ◽  
R. G. Gibilisco ◽  
S. Salgado ◽  
P. Wiesen ◽  
...  
Keyword(s):  
Gas Phase ◽  
Rate Coefficients ◽  
Oh Radicals ◽  
Gas Phase Reactions ◽  
P Rate ◽  
Different Temperatures ◽  
First Time ◽  
Fluorinated Acrylates

Rate coefficients for the gas-phase reactions of OH radicals with a series of fluorinated acrylates and methacrylates have been measured for the first time as a function of temperature in the range 290–308 K.

scholarly journals Temperature dependent rate coefficients for the reactions of the hydroxyl radical with the atmospheric biogenics isoprene, <i>α</i>-pinene and Δ-3-carene

2017 ◽  
Author(s):  
Terry J. Dillon ◽  
Katrin Dulitz ◽  
Christoph M. B. Gross ◽  
John N. Crowley
Keyword(s):  
Cross Sections ◽  
Room Temperature ◽  
Relative Rate ◽  
Gas Pressure ◽  
Rate Coefficients ◽  
Absorption Cross ◽  
Temperature Dependent ◽  
Degradation Reactions ◽  
Dependent Rate ◽  
Accuracy And Precision

Abstract. Abstract. Pulsed laser methods for OH generation and detection were used to study atmospheric degradation reactions for three important biogenic gases: OH + isoprene (R1); OH + α-pinene (R2); and OH + Δ-3-carene (R3). Gas-phase rate coefficients were characterised by non-Arrhenius kinetics for all three reactions. For (R1), k1 (241–356 K) = (1.93 ± 0.08) × 10−11 exp (466 ± 12)/T cm3 molecule−1 s−1 was determined, with a room temperature value of k1 (297 K) = (9.3 ± 0.4) × 10−11 cm3 molecule−1 s−1, independent of bath-gas pressure (5–200 Torr) and composition (M = N2 or air). Accuracy and precision were enhanced by online optical monitoring of isoprene, with absolute concentrations obtained via an absorption cross-section, σisoprene = (1.28 ± 0.06) × 10−17 cm2 molecule−1 at λ = 184.95 nm, determined in this work. These results indicate that significant discrepancies between previous absolute and relative rate determinations of k1 result in part from σ values used to derive the isoprene concentration. Similar methods were used to determine rate coefficients (in 10−11 cm3 molecule−1 s−1) for (R2–R3): k2 (238–357 K) = (1.83 ± 0.04) × exp (330 ± 6)/T; and k3 (235–357 K) = (2.48 ± 0.14) × exp (357 ± 17)/T. This is the first temperature-dependent dataset for (R3) and enables the calculation of reliable atmospheric lifetimes with respect to OH removal for e.g. boreal forest springtime conditions. Room temperature values of k2 (296 K) = (5.4 ± 0.2) × 10−11 cm3 molecule−1 s−1 and k3 (297 K) = (8.1 ± 0.3) × 10−11 cm3 molecule−1 s−1 were independent of bath-gas pressure (7–200 Torr, N2 or air), and in good agreement with previously reported values. In the course of this work, 184.95 nm absorption cross-sections were determined: σ = (1.54 ± 0.08) × 10−17cm 2 molecule−1 for α-pinene and (2.40 ± 0.12) × 10−17  cm2 molecule−1 for Δ-3-carene.

scholarly journals NO<sub>3</sub> chemistry of wildfire emissions: a kinetic study of the gas-phase reactions of furans with the NO<sub>3</sub> radical

2021 ◽  
Author(s):  
Mike J. Newland ◽  
Yangang Ren ◽  
Max R. McGillen ◽  
Lisa Michelat ◽  
Véronique Daële ◽  
...  
Keyword(s):  
Biomass Burning ◽  
Reaction Rate ◽  
Relative Rate ◽  
Rate Coefficients ◽  
Nitrate Radical ◽  
Gas Phase Reactions ◽  
Removal Process ◽  
Order Of Magnitude ◽  
First Time ◽  
Substituted Furans

Abstract. Furans are emitted to the atmosphere during biomass burning from the pyrolysis of cellulose. They are one of the major contributing VOC classes to OH and NO3 reactivity in biomass burning plumes. The major removal process of furans from the atmosphere at night is reaction with the nitrate radical, NO3. Here we report a series of relative rate experiments in the 7300 L indoor simulation chamber at CNRS-ICARE, Orléans, using a number of different reference compounds to determine NO3 reaction rate coefficients for four furans, two furanones, and pyrrole. In the case of the two furanones, this is the first time that NO3 rate coefficients have been reported. The recommended values (cm3 molecule−1 s−1) are: furan (1.50 ± 0.23) × 10−12, 2-methylfuran (2.37 ± 0.55) × 10−11, 2,5-dimethylfuran (1.10 ± 0.33) × 10−10, furan-2-aldehyde (9.28 ± 2.3) × 10−14, 5-methyl-2(3H)-furanone (3.00 ± 0.45) × 10−12, 2(5H)-furanone < 1.410−16, and pyrrole (7.35 ± 2.06) × 10−11. The furan-2-aldehyde + NO3 reaction rate is found to be an order of magnitude lower than previously reported. We also recommend a faster rate for the α-terpinene+NO3 reaction ((2.70 ± 0.81) × 10−10 cm3 s−1). These experiments show that for furan, alkyl substituted furans, 5-methyl-2(3H)-furanone, and pyrrole, reaction with NO3 will be the dominant removal process at night, and may also contribute during the day. For 2(5H)-furanone, reaction with NO3 is not an important atmospheric sink.

scholarly journals Atmospheric fate of two relevant unsaturated ketoethers: kinetics, products and mechanisms for the reaction of hydroxyl radicals with (<i>E</i>)-4-methoxy-3-buten-2-one and 1-(<i>E</i>)-1-methoxy-2-methyl-1-penten-3-one

2020 ◽  
Author(s):  
Rodrigo Gastón Gibilisco ◽  
Ian Barnes ◽  
Iustinian Gabriel Bejan ◽  
Peter Wiesen
Keyword(s):  
Gas Phase ◽  
Hydroxyl Radicals ◽  
Relative Rate ◽  
Reaction Chamber ◽  
Oxidation Products ◽  
Rate Coefficients ◽  
Gas Phase Reactions ◽  
Ozone Formation Potential ◽  
Nitrogen Containing Compounds ◽  
First Time

Abstract. The kinetics of the gas-phase reactions of hydroxyl radicals with two unsaturated methoxy-ketones at (298 ± 3) K and 1 atm of synthetic air have been studied for the first time using the relative rate technique in an environmental reaction chamber by in situ FTIR spectrometry. The rate coefficients obtained using propene and isobutene as reference compounds were (in units of 10–10 cm3 molecule−1 s−1) as follows: k1(OH + (E)-4-methoxy-3-buten-2-one) = (1.42 ± 0.12), and k2(OH + 1-(E)-1-methoxy-2-methyl-1-penten-3-one) = (3.34 ± 0.43). In addition, quantification of the main oxidation products has been performed and degradation mechanisms for these reactions were developed. The formation products and kinetic data confirm that the reactions proceed mainly via an addition of the OH radical to the double bond. Gas phase products, identified and quantified from these reactions, are carbonyls like methyl formate, methyl glyoxal and 2,3-pentanedione and long-lived nitrogen containing compounds such as PAN and PPN. Atmospheric lifetimes and the ozone formation potential have been estimated and possible atmospheric implications assessed.

scholarly journals Gas-phase degradation of 2-butanethiol initiated by OH radicals and Cl atoms: kinetics, product yields and mechanism at 298 K and atmospheric pressure

RSC Advances ◽  
2019 ◽  
Vol 9 (39) ◽  
pp. 22618-22626
Author(s):  
Alejandro L. Cardona ◽  
Rodrigo G. Gibilisco ◽  
María B. Blanco ◽  
Peter Wiesen ◽  
Mariano Teruel
Keyword(s):  
Gas Phase ◽  
Atmospheric Pressure ◽  
Relative Rate ◽  
Product Distribution ◽  
Rate Coefficients ◽  
Oh Radicals ◽  
Product Yields ◽  
Cl Atoms ◽  
Relative Rate Coefficients

Relative rate coefficients and product distribution of the reaction of 2-butanethiol (2butSH) with OH radicals and Cl atoms were obtained at atmospheric pressure and 298 K.

scholarly journals Atmospheric sink of β-ocimene and camphene initiated by Cl atoms: kinetics and products at NOxfree-air

RSC Advances ◽  
2018 ◽  
Vol 8 (48) ◽  
pp. 27054-27063 ◽  
Author(s):  
Elizabeth Gaona-Colmán ◽  
María B. Blanco ◽  
Ian Barnes ◽  
Peter Wiesen ◽  
Mariano A. Teruel
Keyword(s):  
Gas Phase ◽  
Rate Coefficients ◽  
Gas Phase Reactions ◽  
P Rate ◽  
Cl Atoms

Rate coefficients for the gas-phase reactions of Cl atoms with β-ocimene and camphene were determined to be (in units of 10−10cm3per molecule per s) 5.5 ± 0.7 and 3.3 ± 0.4, respectively.

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