On the redox reactions between allyl radicals and NOx

Dapeng Liu; Binod Giri; Milán Szőri; Béla Viskolcz; Et Touhami Essbar; Aamir Farooq

doi:10.1016/j.proci.2020.06.331

On the redox reactions between allyl radicals and NOx

Dapeng Liu, Binod Giri, Milán Szőri, Béla Viskolcz, Et Touhami Essbar, Aamir Farooq

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Abstract

NOx mitigation is a central focus of combustion technologies with increasingly stringent emission regulations. NOx can also enhance the autoignition of hydrocarbon fuels and can promote soot oxidation. The reaction between allyl radical (C3H5) and NOx plays an important role in the oxidation kinetics of propene. In this work, we measured the absolute rate coefficients for the redox reaction between C3H5 and NOx over the temperature range of 1000-1252 K and pressure range of 1.5-5.0 bar using a shock tube and UV laser absorption technique. We produced C3H5 by shock heating of C3H5I behind reflected shock waves. Using a Ti:Sapphire laser system with frequency quadrupling, we monitored the kinetics of C3H5 at 220 nm. Unlike low-temperature chemistry, the two target reactions, C3H5 + NO → products (R1) and C3H5 + NO2 → products (R2), exhibited a strong positive temperature dependence for this radical-radical type reaction. However, these reactions did not show any pressure dependence over the pressure range of 1.5-5.0 bar, indicating that the measured rate coefficients are close to the high-pressure limit. The measured values of the rate coefficients resulted in the following Arrhenius expressions (in unit of cm3/molecule/s):k1 (C3H5 + NO) = 1.49 × 10-10exp (-6083.6K/T)(1017-1252 K) k2 (C3H5 + NO2) = 1.71 × 10-10exp (-3675.7K/T)(1062-1250 K) To our knowledge, these are the first high-temperature measurements of allyl + NOx reactions. The reported data will be highly useful in understanding the interaction of NOx with resonantly stabilized radicals as well as the mutual sensitization effect of NOx on hydrocarbon fuels.

Original language	English (US)
Journal	Proceedings of the Combustion Institute
DOIs	https://doi.org/10.1016/j.proci.2020.06.331
State	Published - Sep 11 2020

Bibliographical note

KAUST Repository Item: Exported on 2020-10-01
Acknowledged KAUST grant number(s): GINOP-2.3.4-15-2016-00004
Acknowledgements: We acknowledge the funding from the Office of Sponsored Research at King Abdullah University of Science and Technology (KAUST). M. Szőri thanks the support from GINOP-2.3.4-15-2016-00004.

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10.1016/j.proci.2020.06.331

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title = "On the redox reactions between allyl radicals and NOx",

abstract = "NOx mitigation is a central focus of combustion technologies with increasingly stringent emission regulations. NOx can also enhance the autoignition of hydrocarbon fuels and can promote soot oxidation. The reaction between allyl radical (C3H5) and NOx plays an important role in the oxidation kinetics of propene. In this work, we measured the absolute rate coefficients for the redox reaction between C3H5 and NOx over the temperature range of 1000-1252 K and pressure range of 1.5-5.0 bar using a shock tube and UV laser absorption technique. We produced C3H5 by shock heating of C3H5I behind reflected shock waves. Using a Ti:Sapphire laser system with frequency quadrupling, we monitored the kinetics of C3H5 at 220 nm. Unlike low-temperature chemistry, the two target reactions, C3H5 + NO → products (R1) and C3H5 + NO2 → products (R2), exhibited a strong positive temperature dependence for this radical-radical type reaction. However, these reactions did not show any pressure dependence over the pressure range of 1.5-5.0 bar, indicating that the measured rate coefficients are close to the high-pressure limit. The measured values of the rate coefficients resulted in the following Arrhenius expressions (in unit of cm3/molecule/s):k1 (C3H5 + NO) = 1.49 × 10-10exp (-6083.6K/T)(1017-1252 K) k2 (C3H5 + NO2) = 1.71 × 10-10exp (-3675.7K/T)(1062-1250 K) To our knowledge, these are the first high-temperature measurements of allyl + NOx reactions. The reported data will be highly useful in understanding the interaction of NOx with resonantly stabilized radicals as well as the mutual sensitization effect of NOx on hydrocarbon fuels.",

author = "Dapeng Liu and Binod Giri and Mil{\'a}n Sz{\H o}ri and B{\'e}la Viskolcz and Essbar, {Et Touhami} and Aamir Farooq",

note = "KAUST Repository Item: Exported on 2020-10-01 Acknowledged KAUST grant number(s): GINOP-2.3.4-15-2016-00004 Acknowledgements: We acknowledge the funding from the Office of Sponsored Research at King Abdullah University of Science and Technology (KAUST). M. Sz{\H o}ri thanks the support from GINOP-2.3.4-15-2016-00004.",

year = "2020",

month = sep,

day = "11",

doi = "10.1016/j.proci.2020.06.331",

language = "English (US)",

journal = "Proceedings of the Combustion Institute",

issn = "1540-7489",

publisher = "Elsevier",

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T1 - On the redox reactions between allyl radicals and NOx

AU - Liu, Dapeng

AU - Giri, Binod

AU - Szőri, Milán

AU - Viskolcz, Béla

AU - Essbar, Et Touhami

AU - Farooq, Aamir

N1 - KAUST Repository Item: Exported on 2020-10-01 Acknowledged KAUST grant number(s): GINOP-2.3.4-15-2016-00004 Acknowledgements: We acknowledge the funding from the Office of Sponsored Research at King Abdullah University of Science and Technology (KAUST). M. Szőri thanks the support from GINOP-2.3.4-15-2016-00004.

PY - 2020/9/11

Y1 - 2020/9/11

N2 - NOx mitigation is a central focus of combustion technologies with increasingly stringent emission regulations. NOx can also enhance the autoignition of hydrocarbon fuels and can promote soot oxidation. The reaction between allyl radical (C3H5) and NOx plays an important role in the oxidation kinetics of propene. In this work, we measured the absolute rate coefficients for the redox reaction between C3H5 and NOx over the temperature range of 1000-1252 K and pressure range of 1.5-5.0 bar using a shock tube and UV laser absorption technique. We produced C3H5 by shock heating of C3H5I behind reflected shock waves. Using a Ti:Sapphire laser system with frequency quadrupling, we monitored the kinetics of C3H5 at 220 nm. Unlike low-temperature chemistry, the two target reactions, C3H5 + NO → products (R1) and C3H5 + NO2 → products (R2), exhibited a strong positive temperature dependence for this radical-radical type reaction. However, these reactions did not show any pressure dependence over the pressure range of 1.5-5.0 bar, indicating that the measured rate coefficients are close to the high-pressure limit. The measured values of the rate coefficients resulted in the following Arrhenius expressions (in unit of cm3/molecule/s):k1 (C3H5 + NO) = 1.49 × 10-10exp (-6083.6K/T)(1017-1252 K) k2 (C3H5 + NO2) = 1.71 × 10-10exp (-3675.7K/T)(1062-1250 K) To our knowledge, these are the first high-temperature measurements of allyl + NOx reactions. The reported data will be highly useful in understanding the interaction of NOx with resonantly stabilized radicals as well as the mutual sensitization effect of NOx on hydrocarbon fuels.

AB - NOx mitigation is a central focus of combustion technologies with increasingly stringent emission regulations. NOx can also enhance the autoignition of hydrocarbon fuels and can promote soot oxidation. The reaction between allyl radical (C3H5) and NOx plays an important role in the oxidation kinetics of propene. In this work, we measured the absolute rate coefficients for the redox reaction between C3H5 and NOx over the temperature range of 1000-1252 K and pressure range of 1.5-5.0 bar using a shock tube and UV laser absorption technique. We produced C3H5 by shock heating of C3H5I behind reflected shock waves. Using a Ti:Sapphire laser system with frequency quadrupling, we monitored the kinetics of C3H5 at 220 nm. Unlike low-temperature chemistry, the two target reactions, C3H5 + NO → products (R1) and C3H5 + NO2 → products (R2), exhibited a strong positive temperature dependence for this radical-radical type reaction. However, these reactions did not show any pressure dependence over the pressure range of 1.5-5.0 bar, indicating that the measured rate coefficients are close to the high-pressure limit. The measured values of the rate coefficients resulted in the following Arrhenius expressions (in unit of cm3/molecule/s):k1 (C3H5 + NO) = 1.49 × 10-10exp (-6083.6K/T)(1017-1252 K) k2 (C3H5 + NO2) = 1.71 × 10-10exp (-3675.7K/T)(1062-1250 K) To our knowledge, these are the first high-temperature measurements of allyl + NOx reactions. The reported data will be highly useful in understanding the interaction of NOx with resonantly stabilized radicals as well as the mutual sensitization effect of NOx on hydrocarbon fuels.

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U2 - 10.1016/j.proci.2020.06.331

DO - 10.1016/j.proci.2020.06.331

M3 - Article

SN - 1540-7489

JO - Proceedings of the Combustion Institute

JF - Proceedings of the Combustion Institute

ER -

On the redox reactions between allyl radicals and NOx

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