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

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.

2017 ◽  
Author(s):  
Siripina Vijayakumar ◽  
Avinash Kumar ◽  
Balla Rajakuma

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.


2016 ◽  
Vol 147 ◽  
pp. 46-54 ◽  
Author(s):  
Elizabeth Gaona-Colmán ◽  
María B. Blanco ◽  
Ian Barnes ◽  
Mariano A. Teruel

2003 ◽  
Vol 3 (6) ◽  
pp. 2233-2307 ◽  
Author(s):  
R. Atkinson

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.


2003 ◽  
Vol 3 (4) ◽  
pp. 4183-4358 ◽  
Author(s):  
R. Atkinson

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.


RSC Advances ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 4264-4273
Author(s):  
P. Lugo García ◽  
C. B. Rivela ◽  
R. G. Gibilisco ◽  
S. Salgado ◽  
P. Wiesen ◽  
...  

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.


2017 ◽  
Author(s):  
Terry J. Dillon ◽  
Katrin Dulitz ◽  
Christoph M. B. Gross ◽  
John N. Crowley

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.


2021 ◽  
Author(s):  
Mike J. Newland ◽  
Yangang Ren ◽  
Max R. McGillen ◽  
Lisa Michelat ◽  
Véronique Daële ◽  
...  

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.


RSC Advances ◽  
2019 ◽  
Vol 9 (39) ◽  
pp. 22618-22626
Author(s):  
Alejandro L. Cardona ◽  
Rodrigo G. Gibilisco ◽  
María B. Blanco ◽  
Peter Wiesen ◽  
Mariano Teruel

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.


RSC Advances ◽  
2018 ◽  
Vol 8 (48) ◽  
pp. 27054-27063 ◽  
Author(s):  
Elizabeth Gaona-Colmán ◽  
María B. Blanco ◽  
Ian Barnes ◽  
Peter Wiesen ◽  
Mariano A. Teruel

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.


RSC Advances ◽  
2017 ◽  
Vol 7 (5) ◽  
pp. 2733-2744 ◽  
Author(s):  
Elizabeth Gaona-Colmán ◽  
María B. Blanco ◽  
Ian Barnes ◽  
Peter Wiesen ◽  
Mariano A. Teruel

Gas-phase rate coefficients for the reactions of OH and O3 with camphene have been measured over the temperature range 288–311 K using the relative rate method.


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