Temperature dependence of the rates of reaction of trifluoroacetic acid with Criegee intermediates

Rabi Chhantyal Pun; Max McGillen; JM Beames; Anwar Khan; Carl J Percival; Dudley Shallcross; Andrew Orr-Ewing

doi:10.1002/ange.201703700

Temperature dependence of the rates of reaction of trifluoroacetic acid with Criegee intermediates

Rabi Chhantyal Pun, Max McGillen, JM Beames, Anwar Khan, Carl J Percival, Dudley Shallcross, Andrew Orr-Ewing

Research output: Contribution to journal › Article (Academic Journal) › peer-review

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Abstract

The rate coefficients for gas-phase reaction of trifluoroacetic acid (TFA) with two Criegee intermediates, formaldehyde oxide and acetone oxide, decrease with increasing temperature in the range 240 – 340 K. The rate coefficients k(CH₂OO + CF₃COOH) = (3.4 +/- 0.3) x 10^-10 cm³ s^-1 and k((CH₃)₂COO + CF₃COOH) = (6.1 +/- 0.2) x 10^-10 cm³ s^-1 at 294 K exceed estimates for collision-limited values, suggesting rate enhancement by capture mechanisms because of the large permanent dipole moments of the two reactants. The observed temperature dependence is attributed to competitive stabilization of a pre-reactive complex. Fits to a model incorporating this complex formation give k [cm³ s^-1] = (3.8 +/- 2.6) x 10^-18 T² exp((1620 +/- 180)/T) + 2.5 x 10^-10 and k [cm³ s^-1] = (4.9 +/- 4.1) x 10^-18 T² exp((1620 +/- 230)/T) + 5.2 x 10^-10 for the CH₂OO + CF₃COOH and (CH₃)₂COO + CF₃COOH reactions, respectively. The consequences are explored for removal of TFA from the atmosphere by reaction with biogenic Criegee intermediates.

Original language	English
Pages (from-to)	9172-9175
Number of pages	4
Journal	Angewandte Chemie - International Edition
Volume	129
Issue number	31
Early online date	29 Jun 2017
DOIs	https://doi.org/10.1002/ange.201703700
Publication status	Published - 24 Jul 2017

Research Groups and Themes

Physical & Theoretical

Keywords

KINETICS
Reactive Intermediates
Atmospheric Chemistry;
Criegee Biradical
Zwitterion
TFA

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10.1002/ange.201703700

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Kinetic Studies of Reactive Intermediates from the Oxidation of Atmospheric Alkenes
Orr-Ewing, A. J. (Principal Investigator)
1/04/17 → 30/09/20
Project: Research
HOMER: Fellowship - Max McGillen
Shallcross, D. E. (Principal Investigator)
4/04/16 → 3/04/18
Project: Research
Gas phase studies of the kinetics of Criegee Intermediates
Shallcross, D. E. (Principal Investigator) & Orr-Ewing, A. J. (Co-Principal Investigator)
30/06/13 → 31/12/16
Project: Research

Professor Andrew J Orr-Ewing
- A.Orr-Ewingbristol.acuk
- School of Chemistry - Professor
Person: Academic , Member
Professor Dudley E Shallcross
- D.E.Shallcrossbristol.acuk
- School of Chemistry - Professor of Atmospheric Chemistry
- Cabot Institute for the Environment
- Atmospheric Chemistry
Person: Academic , Member

Cite this

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title = "Temperature dependence of the rates of reaction of trifluoroacetic acid with Criegee intermediates",

abstract = "The rate coefficients for gas-phase reaction of trifluoroacetic acid (TFA) with two Criegee intermediates, formaldehyde oxide and acetone oxide, decrease with increasing temperature in the range 240 – 340 K. The rate coefficients k(CH2OO + CF3COOH) = (3.4 +/- 0.3) x 10-10 cm3 s-1 and k((CH3)2COO + CF3COOH) = (6.1 +/- 0.2) x 10-10 cm3 s-1 at 294 K exceed estimates for collision-limited values, suggesting rate enhancement by capture mechanisms because of the large permanent dipole moments of the two reactants. The observed temperature dependence is attributed to competitive stabilization of a pre-reactive complex. Fits to a model incorporating this complex formation give k [cm3 s-1] = (3.8 +/- 2.6) x 10-18 T2 exp((1620 +/- 180)/T) + 2.5 x 10-10 and k [cm3 s-1] = (4.9 +/- 4.1) x 10-18 T2 exp((1620 +/- 230)/T) + 5.2 x 10-10 for the CH2OO + CF3COOH and (CH3)2COO + CF3COOH reactions, respectively. The consequences are explored for removal of TFA from the atmosphere by reaction with biogenic Criegee intermediates.",

keywords = "KINETICS, Reactive Intermediates, Atmospheric Chemistry;, Criegee Biradical , Zwitterion, TFA",

author = "\{Chhantyal Pun\}, Rabi and Max McGillen and JM Beames and Anwar Khan and Percival, \{Carl J\} and Dudley Shallcross and Andrew Orr-Ewing",

year = "2017",

month = jul,

day = "24",

doi = "10.1002/ange.201703700",

language = "English",

volume = "129",

pages = "9172--9175",

journal = "Angewandte Chemie - International Edition",

issn = "1433-7851",

publisher = "John Wiley \& Sons, Ltd.",

number = "31",

}

TY - JOUR

T1 - Temperature dependence of the rates of reaction of trifluoroacetic acid with Criegee intermediates

AU - Chhantyal Pun, Rabi

AU - McGillen, Max

AU - Beames, JM

AU - Khan, Anwar

AU - Percival, Carl J

AU - Shallcross, Dudley

AU - Orr-Ewing, Andrew

PY - 2017/7/24

Y1 - 2017/7/24

N2 - The rate coefficients for gas-phase reaction of trifluoroacetic acid (TFA) with two Criegee intermediates, formaldehyde oxide and acetone oxide, decrease with increasing temperature in the range 240 – 340 K. The rate coefficients k(CH2OO + CF3COOH) = (3.4 +/- 0.3) x 10-10 cm3 s-1 and k((CH3)2COO + CF3COOH) = (6.1 +/- 0.2) x 10-10 cm3 s-1 at 294 K exceed estimates for collision-limited values, suggesting rate enhancement by capture mechanisms because of the large permanent dipole moments of the two reactants. The observed temperature dependence is attributed to competitive stabilization of a pre-reactive complex. Fits to a model incorporating this complex formation give k [cm3 s-1] = (3.8 +/- 2.6) x 10-18 T2 exp((1620 +/- 180)/T) + 2.5 x 10-10 and k [cm3 s-1] = (4.9 +/- 4.1) x 10-18 T2 exp((1620 +/- 230)/T) + 5.2 x 10-10 for the CH2OO + CF3COOH and (CH3)2COO + CF3COOH reactions, respectively. The consequences are explored for removal of TFA from the atmosphere by reaction with biogenic Criegee intermediates.

AB - The rate coefficients for gas-phase reaction of trifluoroacetic acid (TFA) with two Criegee intermediates, formaldehyde oxide and acetone oxide, decrease with increasing temperature in the range 240 – 340 K. The rate coefficients k(CH2OO + CF3COOH) = (3.4 +/- 0.3) x 10-10 cm3 s-1 and k((CH3)2COO + CF3COOH) = (6.1 +/- 0.2) x 10-10 cm3 s-1 at 294 K exceed estimates for collision-limited values, suggesting rate enhancement by capture mechanisms because of the large permanent dipole moments of the two reactants. The observed temperature dependence is attributed to competitive stabilization of a pre-reactive complex. Fits to a model incorporating this complex formation give k [cm3 s-1] = (3.8 +/- 2.6) x 10-18 T2 exp((1620 +/- 180)/T) + 2.5 x 10-10 and k [cm3 s-1] = (4.9 +/- 4.1) x 10-18 T2 exp((1620 +/- 230)/T) + 5.2 x 10-10 for the CH2OO + CF3COOH and (CH3)2COO + CF3COOH reactions, respectively. The consequences are explored for removal of TFA from the atmosphere by reaction with biogenic Criegee intermediates.

KW - KINETICS

KW - Reactive Intermediates

KW - Atmospheric Chemistry;

KW - Criegee Biradical

KW - Zwitterion

KW - TFA

U2 - 10.1002/ange.201703700

DO - 10.1002/ange.201703700

M3 - Article (Academic Journal)

SN - 1433-7851

VL - 129

SP - 9172

EP - 9175

JO - Angewandte Chemie - International Edition

JF - Angewandte Chemie - International Edition

IS - 31

ER -

Temperature dependence of the rates of reaction of trifluoroacetic acid with Criegee intermediates

Abstract

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Keywords

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Projects

Kinetic Studies of Reactive Intermediates from the Oxidation of Atmospheric Alkenes

HOMER: Fellowship - Max McGillen

Gas phase studies of the kinetics of Criegee Intermediates

Profiles

Professor Andrew J Orr-Ewing

Professor Dudley E Shallcross

Cite this