Atmospheric chemistry of CH2BrCl: Kinetics and mechanism of the reaction of F atoms with CH2BrCl and fate of the CHBrClO. radical

Merete Bilde; Jens Sehested; Ole John Nielsen; Timothy J. Wallington

Atmospheric chemistry of CH₂BrCl: Kinetics and mechanism of the reaction of F atoms with CH₂BrCl and fate of the CHBrClO^. radical

Merete Bilde, Jens Sehested^*, Ole John Nielsen, Timothy J. Wallington

^*Corresponding author for this work

17 Citations (Scopus)

Abstract

The reaction of F atoms with CH₂BrCl was studied using a pulsed radiolysis technique and found to proceed via two channels: direct hydrogen abstraction and adduct formation. The adduct exists in equilibrium with F atoms and CH₂BrCl. The equilibrium constant K₄ = [Adduct]/([CH₂BrCl][F]) = (4.2 ± 1.0) × 10^-16 cm³molecule^-1. In 1000 mbar total pressure of SF₆ at 294 ± 2 K, the yield of the adduct is 68 ± 11% and the overall rate constant for reaction of F atoms with CH₂BrCl is k₄ (1000 mbar) = (3.6 ± 0.9) × 10^-11 cm³ molecule^-1 s^-1. The adduct reacts with NO with a rate constant of (2.09 ± 0.41) × 10^-11 cm³ molecule^-1 s^-1. The atmospheric fate of the alkoxy radical CHBrClO is Br atom elimination, which occurs at a rate estimated to be >2 × 10⁶ s^-1 in 700 Torr of air at 295 K. Relative rate techniques were used to measure k(Cl + CH₂BrCl) = (4.2 ± 0.5) × 10-¹³ and k(F + CH₂BrCl → CHBrCl + HF) = (1.2 ± 0.4) × 10^-11 cm³ molecule^-1 s^-1. These results are compared to the available literature data.

Original language	English
Journal	Journal of Physical Chemistry A
Volume	101
Issue number	30
Pages (from-to)	5477-5488
Number of pages	12
ISSN	1089-5639
Publication status	Published - 24 Jul 1997

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@article{d3f877ff715c42829977e2d7f6c60f9c,

title = "Atmospheric chemistry of CH2BrCl: Kinetics and mechanism of the reaction of F atoms with CH2BrCl and fate of the CHBrClO. radical",

abstract = "The reaction of F atoms with CH2BrCl was studied using a pulsed radiolysis technique and found to proceed via two channels: direct hydrogen abstraction and adduct formation. The adduct exists in equilibrium with F atoms and CH2BrCl. The equilibrium constant K4 = [Adduct]/([CH2BrCl][F]) = (4.2 ± 1.0) × 10-16 cm3molecule-1. In 1000 mbar total pressure of SF6 at 294 ± 2 K, the yield of the adduct is 68 ± 11% and the overall rate constant for reaction of F atoms with CH2BrCl is k4 (1000 mbar) = (3.6 ± 0.9) × 10-11 cm3 molecule-1 s-1. The adduct reacts with NO with a rate constant of (2.09 ± 0.41) × 10-11 cm3 molecule-1 s-1. The atmospheric fate of the alkoxy radical CHBrClO is Br atom elimination, which occurs at a rate estimated to be >2 × 106 s-1 in 700 Torr of air at 295 K. Relative rate techniques were used to measure k(Cl + CH2BrCl) = (4.2 ± 0.5) × 10-13 and k(F + CH2BrCl → CHBrCl + HF) = (1.2 ± 0.4) × 10-11 cm3 molecule-1 s-1. These results are compared to the available literature data.",

author = "Merete Bilde and Jens Sehested and Nielsen, {Ole John} and Wallington, {Timothy J.}",

year = "1997",

month = jul,

day = "24",

language = "English",

volume = "101",

pages = "5477--5488",

journal = "Journal of Physical Chemistry Part A: Molecules, Spectroscopy, Kinetics, Environment and General Theory",

issn = "1089-5639",

publisher = "American Chemical Society",

number = "30",

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TY - JOUR

T1 - Atmospheric chemistry of CH2BrCl

T2 - Kinetics and mechanism of the reaction of F atoms with CH2BrCl and fate of the CHBrClO. radical

AU - Bilde, Merete

AU - Sehested, Jens

AU - Nielsen, Ole John

AU - Wallington, Timothy J.

PY - 1997/7/24

Y1 - 1997/7/24

N2 - The reaction of F atoms with CH2BrCl was studied using a pulsed radiolysis technique and found to proceed via two channels: direct hydrogen abstraction and adduct formation. The adduct exists in equilibrium with F atoms and CH2BrCl. The equilibrium constant K4 = [Adduct]/([CH2BrCl][F]) = (4.2 ± 1.0) × 10-16 cm3molecule-1. In 1000 mbar total pressure of SF6 at 294 ± 2 K, the yield of the adduct is 68 ± 11% and the overall rate constant for reaction of F atoms with CH2BrCl is k4 (1000 mbar) = (3.6 ± 0.9) × 10-11 cm3 molecule-1 s-1. The adduct reacts with NO with a rate constant of (2.09 ± 0.41) × 10-11 cm3 molecule-1 s-1. The atmospheric fate of the alkoxy radical CHBrClO is Br atom elimination, which occurs at a rate estimated to be >2 × 106 s-1 in 700 Torr of air at 295 K. Relative rate techniques were used to measure k(Cl + CH2BrCl) = (4.2 ± 0.5) × 10-13 and k(F + CH2BrCl → CHBrCl + HF) = (1.2 ± 0.4) × 10-11 cm3 molecule-1 s-1. These results are compared to the available literature data.

AB - The reaction of F atoms with CH2BrCl was studied using a pulsed radiolysis technique and found to proceed via two channels: direct hydrogen abstraction and adduct formation. The adduct exists in equilibrium with F atoms and CH2BrCl. The equilibrium constant K4 = [Adduct]/([CH2BrCl][F]) = (4.2 ± 1.0) × 10-16 cm3molecule-1. In 1000 mbar total pressure of SF6 at 294 ± 2 K, the yield of the adduct is 68 ± 11% and the overall rate constant for reaction of F atoms with CH2BrCl is k4 (1000 mbar) = (3.6 ± 0.9) × 10-11 cm3 molecule-1 s-1. The adduct reacts with NO with a rate constant of (2.09 ± 0.41) × 10-11 cm3 molecule-1 s-1. The atmospheric fate of the alkoxy radical CHBrClO is Br atom elimination, which occurs at a rate estimated to be >2 × 106 s-1 in 700 Torr of air at 295 K. Relative rate techniques were used to measure k(Cl + CH2BrCl) = (4.2 ± 0.5) × 10-13 and k(F + CH2BrCl → CHBrCl + HF) = (1.2 ± 0.4) × 10-11 cm3 molecule-1 s-1. These results are compared to the available literature data.

UR - http://www.scopus.com/inward/record.url?scp=0031189103&partnerID=8YFLogxK

M3 - Journal article

AN - SCOPUS:0031189103

SN - 1089-5639

VL - 101

SP - 5477

EP - 5488

JO - Journal of Physical Chemistry Part A: Molecules, Spectroscopy, Kinetics, Environment and General Theory

JF - Journal of Physical Chemistry Part A: Molecules, Spectroscopy, Kinetics, Environment and General Theory

IS - 30

ER -

Atmospheric chemistry of CH₂BrCl: Kinetics and mechanism of the reaction of F atoms with CH₂BrCl and fate of the CHBrClO^. radical

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