Kinetic study of reaction C2H5+ HO2in a photolysis reactor with time-resolved Faraday rotation spectroscopy

Hongtao Zhong; Chao Yan; Chu C. Teng; Guoming Ma; Gerard Wysocki; Yiguang Ju

doi:10.1016/j.proci.2020.07.095

Kinetic study of reaction C₂H₅+ HO₂in a photolysis reactor with time-resolved Faraday rotation spectroscopy

Hongtao Zhong, Chao Yan, Chu C. Teng, Guoming Ma, Gerard Wysocki, Yiguang Ju

Research output: Contribution to journal › Conference article › peer-review

5 Scopus citations

Abstract

The rate constant and branching ratios of ethyl reaction with hydroperoxyl radical, C₂H₅ + HO₂ (1), a key radical-radical reaction for intermediate temperature combustion chemistry, were measured in situ for the first time in a photolysis Herriott cell by using mid-IR Faraday rotation spectroscopy (FRS) and UV-IR direct absorption spectroscopy (DAS). The microsecond time-resolved diagnostic technique enabled the direct rate measurements of the target reaction at 40 and 80 mbar and reduced the experimental uncertainty considerably. C₂H₅ and HO₂ radicals were generated by the photolysis of (COCl)₂/C₂H₅I/CH₃OH/O₂/He mixture at 266 nm. By direct measurements of the transient profiles of C₂H₅, HO₂ and OH concentrations, the overall rate constant for this reaction at 297 K was determined as k 1 (40 mbar) = (3.8 ± 0.8) × 10⁻¹¹ cu cm/molecule−s and k1 (80 mbar) = (4.1 ± 1.0) × 10⁻¹¹ cu cm/molecule−s . The direct observation of hydroxyl radical (OH) indicated that OH formation channel was the major channel with a branching ratio of 0.8 ± 0.1.

Original language	English (US)
Pages (from-to)	871-880
Number of pages	10
Journal	Proceedings of the Combustion Institute
Volume	38
Issue number	1
DOIs	https://doi.org/10.1016/j.proci.2020.07.095
State	Published - 2021
Event	38th International Symposium on Combustion, 2021 - Adelaide, Australia Duration: Jan 24 2021 → Jan 29 2021

All Science Journal Classification (ASJC) codes

General Chemical Engineering
Mechanical Engineering
Physical and Theoretical Chemistry

Keywords

Chemical kinetics
Faraday rotation spectroscopy
Hydroperoxyl radical
Radical-radical reaction
Rate constant

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10.1016/j.proci.2020.07.095

Cite this

@article{fc68b11577494104be8c48ee492cb0cb,

title = "Kinetic study of reaction C2H5+ HO2in a photolysis reactor with time-resolved Faraday rotation spectroscopy",

abstract = "The rate constant and branching ratios of ethyl reaction with hydroperoxyl radical, C2H5 + HO2 (1), a key radical-radical reaction for intermediate temperature combustion chemistry, were measured in situ for the first time in a photolysis Herriott cell by using mid-IR Faraday rotation spectroscopy (FRS) and UV-IR direct absorption spectroscopy (DAS). The microsecond time-resolved diagnostic technique enabled the direct rate measurements of the target reaction at 40 and 80 mbar and reduced the experimental uncertainty considerably. C2H5 and HO2 radicals were generated by the photolysis of (COCl)2/C2H5I/CH3OH/O2/He mixture at 266 nm. By direct measurements of the transient profiles of C2H5, HO2 and OH concentrations, the overall rate constant for this reaction at 297 K was determined as k 1 (40 mbar) = (3.8 ± 0.8) × 10−11 cu cm/molecule−s and k1 (80 mbar) = (4.1 ± 1.0) × 10−11 cu cm/molecule−s . The direct observation of hydroxyl radical (OH) indicated that OH formation channel was the major channel with a branching ratio of 0.8 ± 0.1.",

keywords = "Chemical kinetics, Faraday rotation spectroscopy, Hydroperoxyl radical, Radical-radical reaction, Rate constant",

author = "Hongtao Zhong and Chao Yan and Teng, {Chu C.} and Guoming Ma and Gerard Wysocki and Yiguang Ju",

note = "Funding Information: This work was supported by NSF grants CBET 1903362 and 1507358 . We acknowledge Dr. Stephen J. Klippenstein for helpful discussions. ; 38th International Symposium on Combustion, 2021 ; Conference date: 24-01-2021 Through 29-01-2021",

year = "2021",

doi = "10.1016/j.proci.2020.07.095",

language = "English (US)",

volume = "38",

pages = "871--880",

journal = "Proceedings of the Combustion Institute",

issn = "1540-7489",

publisher = "Elsevier Ltd",

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TY - JOUR

T1 - Kinetic study of reaction C2H5+ HO2in a photolysis reactor with time-resolved Faraday rotation spectroscopy

AU - Zhong, Hongtao

AU - Yan, Chao

AU - Teng, Chu C.

AU - Ma, Guoming

AU - Wysocki, Gerard

AU - Ju, Yiguang

N1 - Funding Information: This work was supported by NSF grants CBET 1903362 and 1507358 . We acknowledge Dr. Stephen J. Klippenstein for helpful discussions.

PY - 2021

Y1 - 2021

N2 - The rate constant and branching ratios of ethyl reaction with hydroperoxyl radical, C2H5 + HO2 (1), a key radical-radical reaction for intermediate temperature combustion chemistry, were measured in situ for the first time in a photolysis Herriott cell by using mid-IR Faraday rotation spectroscopy (FRS) and UV-IR direct absorption spectroscopy (DAS). The microsecond time-resolved diagnostic technique enabled the direct rate measurements of the target reaction at 40 and 80 mbar and reduced the experimental uncertainty considerably. C2H5 and HO2 radicals were generated by the photolysis of (COCl)2/C2H5I/CH3OH/O2/He mixture at 266 nm. By direct measurements of the transient profiles of C2H5, HO2 and OH concentrations, the overall rate constant for this reaction at 297 K was determined as k 1 (40 mbar) = (3.8 ± 0.8) × 10−11 cu cm/molecule−s and k1 (80 mbar) = (4.1 ± 1.0) × 10−11 cu cm/molecule−s . The direct observation of hydroxyl radical (OH) indicated that OH formation channel was the major channel with a branching ratio of 0.8 ± 0.1.

AB - The rate constant and branching ratios of ethyl reaction with hydroperoxyl radical, C2H5 + HO2 (1), a key radical-radical reaction for intermediate temperature combustion chemistry, were measured in situ for the first time in a photolysis Herriott cell by using mid-IR Faraday rotation spectroscopy (FRS) and UV-IR direct absorption spectroscopy (DAS). The microsecond time-resolved diagnostic technique enabled the direct rate measurements of the target reaction at 40 and 80 mbar and reduced the experimental uncertainty considerably. C2H5 and HO2 radicals were generated by the photolysis of (COCl)2/C2H5I/CH3OH/O2/He mixture at 266 nm. By direct measurements of the transient profiles of C2H5, HO2 and OH concentrations, the overall rate constant for this reaction at 297 K was determined as k 1 (40 mbar) = (3.8 ± 0.8) × 10−11 cu cm/molecule−s and k1 (80 mbar) = (4.1 ± 1.0) × 10−11 cu cm/molecule−s . The direct observation of hydroxyl radical (OH) indicated that OH formation channel was the major channel with a branching ratio of 0.8 ± 0.1.

KW - Chemical kinetics

KW - Faraday rotation spectroscopy

KW - Hydroperoxyl radical

KW - Radical-radical reaction

KW - Rate constant

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