Temperature and Pressure Studies of the Reactions of CH₃O₂, HO₂, and 1,2-C₄H₉O₂ with NO₂

Abstract

A novel technique has been developed for the detection of peroxy radicals in order to study their kinetics with NO 2 . Peroxy radicals (RO 2 , where R = H, CH 3 and 1-,2-C 4 H 9 ) were produced by laser flash photolysis and were probed by

Slow photoelectron velocity-map imaging of cold tert-butyl peroxide

“…[1][2][3][4][5] Atmospheric reactions of alkyl peroxy radicals with NO result in the formation of tropospheric ozone, 6,7 motivating a large body of work studying the kinetics of reactions of alkyl peroxy radicals with nitroxides. [8][9][10] In the absence of nitroxide pollutants, alkyl peroxy radicals can undergo self-reactions, [11][12][13] addition to other species, 14 and unimolecular decomposition. 15,16 Many of these processes also play a role in low-temperature combustion of hydrocarbons, where alkyl peroxy radicals are an important class of reactive intermediates that exhibit complex, temperaturedependent chemistry.…”

Impact of temperature-dependent non-PAN peroxynitrate formation, RO2NO2, on nighttime atmospheric chemistry

“…Concentrations of HO 2 and RO 2 radicals, as well as of O 3 , NO 2 , and VOCs were measured and are compared to zerodimensional box model calculations, incorporating stateof-the-art oxidation schemes. The reaction of non-acyl RO 2 radicals with NO 2 forming RO 2 NO 2 and its backward reaction are implemented in the chemical mechanisms of cis-2-butene and trans-2-hexene by using literature values, 12,[16][17][18] and the implications of the findings on the nighttime atmospheric RO 2 chemistry are discussed. The newly introduced ozonolysis scheme and RO 2 isomerisation reactions, suggested by Novelli et al 10 for cis-2-butene and trans-2-hexene, as well as their temperature dependence are tested and model-measurement comparisons are used to improve the chemical mechanisms for these species.…”

“…Temperature-dependent rate coefficients for the formation and decomposition of different alkyl peroxynitrates, adopted from Jenkin et al12 Rate coefficients are given for ambient pressure (1013 hPa) and T = 276 K, 292 K, and 305 K Recommended by IUPAC 16. b Determined from isomeric mixtures formed from the reaction of chlorine with butane17,18 and recommended by Jenkin et al 12 c Determined from isomeric mixtures formed from the reaction of chlorine with hexane18 and recommended by Jenkin et al12 d Pressure-independent generic rate coefficient recommended by Jenkin et al…”

Mid-infrared quantum cascade laser spectroscopy probing of the kinetics of an atmospherically significant radical reaction, $$\hbox {CH}_{3}\hbox {O}_{2}+\hbox {NO}_{2}+\hbox {M}\rightarrow \hbox {CH}_{3}\hbox {O}_{2}\hbox {NO}_{2}+\hbox {M}$$ CH 3

“…36 Very recently, McKee et al, studied the kinetics of the reaction as well as equilibrium parameters for the process CH 3 O 2 + NO 2 ↔ CH 3 O 2 NO 2 by probing CH 3 O 2 radicals indirectly. 37 CH 3 O 2 was photolyzed to produce CH 3 O and OH radicals, and these secondary radicals were probed by laser induced fluorescence spectroscopic method. Figure 5 represents a typical decay profile for IR absorption of CH 3 O 2 radical at the probing wavelength (9.1 μm) in presence of NO 2 under the condition of a fast flow of the reaction gas mixture within the reactor.…”

“…Although kinetics of this reaction has been studied before by several methods, we report here the measurement of the same by direct IR absorption monitoring of CH 3 O 2 radical for the first time. [30][31][32][33][34][35][36][37] Recently, Lee and co-workers measured vibrational spectrum of various peroxy radicals in the mid-infrared by Step-Scan FTIR method at low spectral resolutions, but no kinetic data of those radicals were reported using this method. [38][39][40] We also have measured for the first time the infrared absorption cross-section of the peroxy radical near the band maximum of its O-O stretching fundamental.…”