Reactions of methylperoxy radicals with nitric oxide and nitrogen dioxide

Abstract

The photooxidation of CH3N2CH3 was studied at 25°in the presence of NO and N02. The reaction conditions were [CH3N2CH3] from 1.6 to 29.1 Torr, [02] from 2.3 to 30.7 Torr, h from 0.024 to 0.56 µ sec, and [NO] from 19 to 91 µ or [N02] from 31 to 142 µ. In most runs about 100 Torr of N2 was also present. Both 14N and 15N isotopes were used in the NO and N02, and the product peaks monitored mass spectrometrically. For some runs gas chromatography was also employed, and in some cases CH3I replaced CH3N2CH3 as a source of CH3 radicals. With either NO or N02 the major product of the reaction was CH30N02, though it appeared with an induction period in the NO studies. HCOOH was also produced with an induction period in both studies. Its presence strongly infers the production of CH20 as a primary product. The CH3Q2 radicals appear to react with the oxides of nitrogen via CH302 + NO -* CH302NO (10a), CH302 + NO -* CH20 + MONO (10b), CH302 + N02 -* CH20 + BONO, (12a), CH302 + N02 -* CH302N02 (12c), with kl0,/kl0 = 0.6 ± 0.1 and k12c/k12 = 0.75 ± 0.05, where kw = k20a + Ari0b and ki2 = k22a + ki2r.• There was no evidence for the reaction between CH302 and NO producing CHsO + N02, and it occurs <2% of the time. The CH302N0 molecule isomerizes to CH30N02 in a third-order reaction 2CH302N0 + 02 -»• 2CH3ON02 + 02 (11), with kn = 0.11 Torr-2 sec-1. CH302N02 apparently reacts rapidly with both N02 and NO, CH302N02 + NOz -CH3ON02 + NOs ( 14) and CH302N02 + NO -* CH3ONO + NOs (15). Of primary concern in the understanding of photo-mechanism by which nitric oxide is converted to nitrochemical smog formation is the elucidation of the gen dioxide in urban atmospheres. It is well known that the third-order reaction with oxygen (k = 7 X(1) Environmental Protection Agency Air Pollution Trainee.

The Photooxidation of 2-Bromoethanol

“…5 However, our results do not rule out the possibility of nitrate formation Typically nitrates do not show parent mass spectral peaks, the predominant high mass peak corresponding to NO2 + . Two methods have been reported 6 -7 for the synthesis of HO-C2H1ONO2.…”

“…A number of runs were done with either 36-140 mtorr of reactions of CH3O2 radicals, 5 (ID These peroxy compounds may revert to the nitrate, (HOC2-H4ONO2), which is probably the product observed. 5 However, our results do not rule out the possibility of nitrate formation Typically nitrates do not show parent mass spectral peaks, the predominant high mass peak corresponding to NO2 + .…”

Nitrogen dioxide catalyzed geometric isomerization of olefins. Isomerization kinetics of the 2-butenes and 2-pentenes

“…IT], } (5) [CIO + [TI0 eq 5 allowed the raw rate constants (kcis or ktrans) calculated using eq 3 to be corrected for the perturbing effects of reverse isomerization. To do this the raw values for kois and ktrans were used to calculate an initial set of Arrhenius parameters for these rate constants.…”

Photooxidation of Azomethane

“…The experimental apparatus and procedure were identical to those reported elsewhere (6). Reaction mixtures were photolyzed in a 500 cc spherical glass vessel at 25 + 2 "C. The reaction gases exited continuously through a capillary tube connected to 8 mm Pyrex tubing which led through a pinhole to a modified E.A.I.…”