OH-initiated oxidation of benzene - Part II. Influence of elevated NOx concentrations

B Klotz; R Volkamer; MD Hurley; Mads Peter Sulbæk Andersen; OJ Nielsen; I Barnes; T Imamura; K Wirtz; KH Becker; U Platt; TJ Wallington; N Washida

doi:10.1039/b204398j

OH-initiated oxidation of benzene - Part II. Influence of elevated NOx concentrations

B Klotz, R Volkamer, MD Hurley, Mads Peter Sulbæk Andersen, OJ Nielsen, I Barnes, T Imamura, K Wirtz, KH Becker, U Platt, TJ Wallington, N Washida

Kemisk Institut

52 Citationer (Scopus)

Abstract

The present work represents a continuation of part I of this series of papers, in which we investigated the phenol yields in the OH-initiated oxidation of benzene under conditions of low to moderate concentrations of NOx, to elevated NOx levels. The products of the OH-initiated oxidation of benzene in 700 760 Torr of N-2/O-2 diluent at 297 +/- 4 K were investigated in 3 different photochemical reaction chambers. In situ spectroscopic techniques were employed for the detection of products, and the initial concentrations of benzene, NOx, and O-2 were widely varied (by factors of 6300, 1500, and 13, respectively). In contrast to results from previous studies, a pronounced dependence of the product distribution on the NOx concentration was observed. The phenol yield decreases from approximately 50-60% in the presence of low concentrations (10 000 ppb) NOx concentrations. In the presence of high concentrations of NOx, the phenol yield increases with increasing O-2 partial pressure. The rate constant of the reaction of hydroxycyclohexadienyl peroxyl radicals with NO was determined to be (1.7 +/- 0.6) x 10(-11) cm(3) molecule(-1) s(-1). This reaction leads to the formation of E, E-2,4-hexadienedial as the main identiable product (29 +/- 16. The reaction of the hydroxycyclohexadienyl radical with NO2 gave phenol (5.9 +/- 3.4 and E,E-2,4-hexadienedial (3.4 +/- 1.9, no other products could be identified. The residual FTIR product spectra indicate the formation of unknown nitrates or other nitrogen-containing species in high yield. The results from the present work also show that experimental studies aimed at establishing/verifying chemical mechanisms for aromatic hydrocarbons must be performed using NOx levels which are representative of those found in the atmosphere.

Originalsprog	Udefineret/Ukendt
Tidsskrift	Physical Chemistry Chemical Physics
Vol/bind	4
Udgave nummer	18
Sider (fra-til)	4399-4411
Antal sider	13
ISSN	1463-9076
DOI	https://doi.org/10.1039/b204398j
Status	Udgivet - 2002

Adgang til dokumentet

10.1039/b204398j

Citationsformater

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title = "OH-initiated oxidation of benzene - Part II. Influence of elevated NOx concentrations",

abstract = "The present work represents a continuation of part I of this series of papers, in which we investigated the phenol yields in the OH-initiated oxidation of benzene under conditions of low to moderate concentrations of NOx, to elevated NOx levels. The products of the OH-initiated oxidation of benzene in 700 760 Torr of N-2/O-2 diluent at 297 +/- 4 K were investigated in 3 different photochemical reaction chambers. In situ spectroscopic techniques were employed for the detection of products, and the initial concentrations of benzene, NOx, and O-2 were widely varied (by factors of 6300, 1500, and 13, respectively). In contrast to results from previous studies, a pronounced dependence of the product distribution on the NOx concentration was observed. The phenol yield decreases from approximately 50-60% in the presence of low concentrations (10 000 ppb) NOx concentrations. In the presence of high concentrations of NOx, the phenol yield increases with increasing O-2 partial pressure. The rate constant of the reaction of hydroxycyclohexadienyl peroxyl radicals with NO was determined to be (1.7 +/- 0.6) x 10(-11) cm(3) molecule(-1) s(-1). This reaction leads to the formation of E, E-2,4-hexadienedial as the main identiable product (29 +/- 16. The reaction of the hydroxycyclohexadienyl radical with NO2 gave phenol (5.9 +/- 3.4 and E,E-2,4-hexadienedial (3.4 +/- 1.9, no other products could be identified. The residual FTIR product spectra indicate the formation of unknown nitrates or other nitrogen-containing species in high yield. The results from the present work also show that experimental studies aimed at establishing/verifying chemical mechanisms for aromatic hydrocarbons must be performed using NOx levels which are representative of those found in the atmosphere.",

author = "B Klotz and R Volkamer and MD Hurley and Andersen, {Mads Peter Sulb{\ae}k} and OJ Nielsen and I Barnes and T Imamura and K Wirtz and KH Becker and U Platt and TJ Wallington and N Washida",

year = "2002",

doi = "10.1039/b204398j",

language = "Udefineret/Ukendt",

volume = "4",

pages = "4399--4411",

journal = "Physical Chemistry Chemical Physics",

issn = "1463-9076",

publisher = "Royal Society of Chemistry",

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TY - JOUR

T1 - OH-initiated oxidation of benzene - Part II. Influence of elevated NOx concentrations

AU - Klotz, B

AU - Volkamer, R

AU - Hurley, MD

AU - Andersen, Mads Peter Sulbæk

AU - Nielsen, OJ

AU - Barnes, I

AU - Imamura, T

AU - Wirtz, K

AU - Becker, KH

AU - Platt, U

AU - Wallington, TJ

AU - Washida, N

PY - 2002

Y1 - 2002

N2 - The present work represents a continuation of part I of this series of papers, in which we investigated the phenol yields in the OH-initiated oxidation of benzene under conditions of low to moderate concentrations of NOx, to elevated NOx levels. The products of the OH-initiated oxidation of benzene in 700 760 Torr of N-2/O-2 diluent at 297 +/- 4 K were investigated in 3 different photochemical reaction chambers. In situ spectroscopic techniques were employed for the detection of products, and the initial concentrations of benzene, NOx, and O-2 were widely varied (by factors of 6300, 1500, and 13, respectively). In contrast to results from previous studies, a pronounced dependence of the product distribution on the NOx concentration was observed. The phenol yield decreases from approximately 50-60% in the presence of low concentrations (10 000 ppb) NOx concentrations. In the presence of high concentrations of NOx, the phenol yield increases with increasing O-2 partial pressure. The rate constant of the reaction of hydroxycyclohexadienyl peroxyl radicals with NO was determined to be (1.7 +/- 0.6) x 10(-11) cm(3) molecule(-1) s(-1). This reaction leads to the formation of E, E-2,4-hexadienedial as the main identiable product (29 +/- 16. The reaction of the hydroxycyclohexadienyl radical with NO2 gave phenol (5.9 +/- 3.4 and E,E-2,4-hexadienedial (3.4 +/- 1.9, no other products could be identified. The residual FTIR product spectra indicate the formation of unknown nitrates or other nitrogen-containing species in high yield. The results from the present work also show that experimental studies aimed at establishing/verifying chemical mechanisms for aromatic hydrocarbons must be performed using NOx levels which are representative of those found in the atmosphere.

AB - The present work represents a continuation of part I of this series of papers, in which we investigated the phenol yields in the OH-initiated oxidation of benzene under conditions of low to moderate concentrations of NOx, to elevated NOx levels. The products of the OH-initiated oxidation of benzene in 700 760 Torr of N-2/O-2 diluent at 297 +/- 4 K were investigated in 3 different photochemical reaction chambers. In situ spectroscopic techniques were employed for the detection of products, and the initial concentrations of benzene, NOx, and O-2 were widely varied (by factors of 6300, 1500, and 13, respectively). In contrast to results from previous studies, a pronounced dependence of the product distribution on the NOx concentration was observed. The phenol yield decreases from approximately 50-60% in the presence of low concentrations (10 000 ppb) NOx concentrations. In the presence of high concentrations of NOx, the phenol yield increases with increasing O-2 partial pressure. The rate constant of the reaction of hydroxycyclohexadienyl peroxyl radicals with NO was determined to be (1.7 +/- 0.6) x 10(-11) cm(3) molecule(-1) s(-1). This reaction leads to the formation of E, E-2,4-hexadienedial as the main identiable product (29 +/- 16. The reaction of the hydroxycyclohexadienyl radical with NO2 gave phenol (5.9 +/- 3.4 and E,E-2,4-hexadienedial (3.4 +/- 1.9, no other products could be identified. The residual FTIR product spectra indicate the formation of unknown nitrates or other nitrogen-containing species in high yield. The results from the present work also show that experimental studies aimed at establishing/verifying chemical mechanisms for aromatic hydrocarbons must be performed using NOx levels which are representative of those found in the atmosphere.

U2 - 10.1039/b204398j

DO - 10.1039/b204398j

M3 - Tidsskriftartikel

SN - 1463-9076

VL - 4

SP - 4399

EP - 4411

JO - Physical Chemistry Chemical Physics

JF - Physical Chemistry Chemical Physics

IS - 18

ER -