Near-IR kinetic spectroscopy (IRKS) of the HO2 and C2H5O2 self and cross reactions

Aaron C. Noell; Leah S. Alconcel; D. J. Robichaud; Mitchio Okumura; S. P. Sander

Near-IR kinetic spectroscopy (IRKS) of the HO₂ and C₂H₅O₂ self and cross reactions

Aaron C. Noell^*, Leah S. Alconcel, D. J. Robichaud, Mitchio Okumura, S. P. Sander

^*Corresponding author for this work

Metallurgy and Materials

Research output: Chapter in Book/Report/Conference proceeding › Conference contribution

Abstract

Peroxy radical (RO₂) chemistry is central to the oxidation of volatile organic carbon in the troposphere. Kinetic studies of their reactions are rendered difficult by competing self- and cross-reactions, especially the poorly characterized secondary production of HO₂ from RO₂ self-reactions. In this experiment C₂H₅O₂ and HO₂, were generated by pulsed laser photolysis and monitored simultaneously and independently using UV absorption and wavelength modulation near-IR spectroscopies. Their self- and cross-reactions were investigated over a wide range of relative concentrations, at T=221-296 K and p=50-200 Torr. The Arrhenius expression for the cross reaction rate constant is k₂(T) = (5.58±1.80) × 10^-13 exp(672±74) cm³ molecules^-1 s^-1, and is in general agreement with previous studies. The high sensitivity for HO₂ detection led to the first direct measurement of the branching fraction to the radical channel in the C₂H₅O₂ self-reaction. The result, α = 0.24±0.05 is less than half that reported in the literature.

Original language	English
Title of host publication	American Chemical Society - 235th National Meeting, Abstracts of Scientific Papers
Publication status	Published - 2008
Event	235th National Meeting of the American Chemical Society, ACS 2008 - New Orleans, LA, United States Duration: 6 Apr 2008 → 10 Apr 2008

Publication series

Name	ACS National Meeting Book of Abstracts
ISSN (Print)	0065-7727

Conference

Conference	235th National Meeting of the American Chemical Society, ACS 2008
Country/Territory	United States
City	New Orleans, LA
Period	6/04/08 → 10/04/08

ASJC Scopus subject areas

General Chemistry
General Chemical Engineering

Cite this

@inproceedings{0c0f46b20cb740a4b9e1c0cd2e61200d,

title = "Near-IR kinetic spectroscopy (IRKS) of the HO2 and C2H5O2 self and cross reactions",

abstract = "Peroxy radical (RO2) chemistry is central to the oxidation of volatile organic carbon in the troposphere. Kinetic studies of their reactions are rendered difficult by competing self- and cross-reactions, especially the poorly characterized secondary production of HO2 from RO2 self-reactions. In this experiment C2H5O2 and HO2, were generated by pulsed laser photolysis and monitored simultaneously and independently using UV absorption and wavelength modulation near-IR spectroscopies. Their self- and cross-reactions were investigated over a wide range of relative concentrations, at T=221-296 K and p=50-200 Torr. The Arrhenius expression for the cross reaction rate constant is k2(T) = (5.58±1.80) × 10-13 exp(672±74) cm3 molecules-1 s-1, and is in general agreement with previous studies. The high sensitivity for HO2 detection led to the first direct measurement of the branching fraction to the radical channel in the C2H5O2 self-reaction. The result, α = 0.24±0.05 is less than half that reported in the literature.",

author = "Noell, {Aaron C.} and Alconcel, {Leah S.} and Robichaud, {D. J.} and Mitchio Okumura and Sander, {S. P.}",

year = "2008",

language = "English",

isbn = "9780841269859",

series = "ACS National Meeting Book of Abstracts",

booktitle = "American Chemical Society - 235th National Meeting, Abstracts of Scientific Papers",

note = "235th National Meeting of the American Chemical Society, ACS 2008 ; Conference date: 06-04-2008 Through 10-04-2008",

}

Noell, AC, Alconcel, LS, Robichaud, DJ, Okumura, M & Sander, SP 2008, Near-IR kinetic spectroscopy (IRKS) of the HO₂ and C₂H₅O₂ self and cross reactions. in American Chemical Society - 235th National Meeting, Abstracts of Scientific Papers. ACS National Meeting Book of Abstracts, 235th National Meeting of the American Chemical Society, ACS 2008, New Orleans, LA, United States, 6/04/08.

TY - GEN

T1 - Near-IR kinetic spectroscopy (IRKS) of the HO2 and C2H5O2 self and cross reactions

AU - Noell, Aaron C.

AU - Alconcel, Leah S.

AU - Robichaud, D. J.

AU - Okumura, Mitchio

AU - Sander, S. P.

PY - 2008

Y1 - 2008

N2 - Peroxy radical (RO2) chemistry is central to the oxidation of volatile organic carbon in the troposphere. Kinetic studies of their reactions are rendered difficult by competing self- and cross-reactions, especially the poorly characterized secondary production of HO2 from RO2 self-reactions. In this experiment C2H5O2 and HO2, were generated by pulsed laser photolysis and monitored simultaneously and independently using UV absorption and wavelength modulation near-IR spectroscopies. Their self- and cross-reactions were investigated over a wide range of relative concentrations, at T=221-296 K and p=50-200 Torr. The Arrhenius expression for the cross reaction rate constant is k2(T) = (5.58±1.80) × 10-13 exp(672±74) cm3 molecules-1 s-1, and is in general agreement with previous studies. The high sensitivity for HO2 detection led to the first direct measurement of the branching fraction to the radical channel in the C2H5O2 self-reaction. The result, α = 0.24±0.05 is less than half that reported in the literature.

AB - Peroxy radical (RO2) chemistry is central to the oxidation of volatile organic carbon in the troposphere. Kinetic studies of their reactions are rendered difficult by competing self- and cross-reactions, especially the poorly characterized secondary production of HO2 from RO2 self-reactions. In this experiment C2H5O2 and HO2, were generated by pulsed laser photolysis and monitored simultaneously and independently using UV absorption and wavelength modulation near-IR spectroscopies. Their self- and cross-reactions were investigated over a wide range of relative concentrations, at T=221-296 K and p=50-200 Torr. The Arrhenius expression for the cross reaction rate constant is k2(T) = (5.58±1.80) × 10-13 exp(672±74) cm3 molecules-1 s-1, and is in general agreement with previous studies. The high sensitivity for HO2 detection led to the first direct measurement of the branching fraction to the radical channel in the C2H5O2 self-reaction. The result, α = 0.24±0.05 is less than half that reported in the literature.

UR - http://www.scopus.com/inward/record.url?scp=77955609547&partnerID=8YFLogxK

M3 - Conference contribution

AN - SCOPUS:77955609547

SN - 9780841269859

T3 - ACS National Meeting Book of Abstracts

BT - American Chemical Society - 235th National Meeting, Abstracts of Scientific Papers

T2 - 235th National Meeting of the American Chemical Society, ACS 2008

Y2 - 6 April 2008 through 10 April 2008

ER -