Oxidation by atomic oxygen

The oxidation of alkenes by nitrous oxide on silver at 350°C has been studied from the viewpoint of structure effects on rate by Belousov, Mulik, and Rubanik (J40), and very good correlations of Type B have been found with ionization potentials and with the rate of oxidation by atomic oxygen (series 110 and 111). 

A. Namiki, XPS study on early stages of oxidation by atomic oxygen in silicon surfaces, Solid-State Electron. 33, 107, 1990. 

J. T. Roberts, R. J. Madix, Epoxidation of olefins on silver Conversion of norbomene to norbor-nene oxide by atomic oxygen on silver(llO), /. Am. Chem. Soc. 110 (1980) 8540. 

The initiation stage during the oxidation by atomic oxygen is a direct... 

This result calls into question mechanisms in which the reducing agent reacts directly with valence-band holes. Honda and coworkers proposed that formate is oxidized by atomic oxygen formed in the photoanodic oxidation of ZnO. 

Reduction by ethylene glycol competes with oxidation by atomic oxygen, setting up an equilibrium between Fe(lll) and Fe(ll). Reprinted with permission from Ref [89] ... 

Shibata M, Furuya N, Watanabe M. 1987. Electrocatalysis by ad-atoms. Part XXL Catal3ftic effects on the elementary steps in methanol oxidation by non-oxygen-adsorbing ad-atoms. J Electroanal Chem 229 385-394. 

The active enzyme abstracts a hydrogen atom stereospecifically from the intervening methylene group of a PUFA in a rate-limiting step, with the iron being reduced to Fe(II). The enzyme-alkyl radical complex is then oxidized by molecular oxygen to an enzyme-peroxy radical complex under aerobic conditions, before the electron is transferred from the ferrous atom to the peroxy group. Protonation and dissociation from... 

Regulation of the Methanol Oxidation by Extra Oxygen Atoms. ..242... 

However, 03 does not appear to react with CO below 523 K. Since CO is apparently oxidized by the oxygen atoms formed by the decomposition of ozone [the reverse of reaction (3.37)], the reaction must have a high activation energy (>120kJ/mol). This oxidation of CO by O atoms was thought to be rapid in the high-temperature range, but one must recall that it is a three-body recombination reaction. 

The 1,3,4-thiazaphospholes are colorless, yellow, or red crystalline solids <85AG125> the 2-phenyl derivative is a pale yellow liquid. They are not oxidized by atmospheric oxygen or sulfur <86PS(28)7i>. Dimethyl sulfate or trimethyloxonium tetrafluoroborate methylates the nitrogen atom <85AG125,... 

Two types of reaction are observed for thioketones that do not have parallels in ketone photochemistry. The first is photocyclization in thioketones with polycyclic aromatic groups (4.104), where the sulfur atom forms a new bond to the aromatic system. The second is photo-oxidation by singlet oxygen to give the corresponding carbonyl compound 4.10S), possibly via a 1,2,3-dioxathietane formed as a result of initial cycloaddition. 

This reaction comprises firstly of SH2 reaction on the iodine atom of ethyl iodoacetate by an ethyl radical, formed from triethylborane and molecular oxygen, to form a more stable Chester radical and ethyl iodide. Electrophilic addition of the a-ester radical to electron-rich aromatics (36) forms an adduct radical, and finally abstraction of a hydrogen atom from the adduct by the ethyl radical or oxidation by molecular oxygen generates ethyl arylacetate (37), as shown in eq. 5.20. Here, a nucleophilic ethyl radical does not react with electron-rich aromatics (36), while only an electrophilic a-ester radical reacts with electron-rich aromatics via SOMO-HOMO interaction. 

Excitation by the actinic radiation in the troposphere (290 < X < 420 nm, Figure 9.6b) induces dissociation to nitric oxide and atomic oxygen in their ground states ... 

Carboxin was much more readily photodegraded than oxycarboxin in pure water. The oxidation of the sulphur atom yielded the sulphoxide Va and the subsequent loss of the heterocyclic ring produced the oxanilic acid Vb (see Scheme 6). Humic substances enhanced the phototransformation of both fungicides. For carboxin, this enhancement is possibly related to the presence of the sulphur atom that might be oxidized by singlet oxygen or other photo-oxidants. 

Popov " studied the oxidation of CO by atomic oxygen, which was produced by the photodissociation of O2 in the Schumann-Runge region (X < 1750 A). The rate of formation of CO2 varied linearly with [O2] in the pressure range of 0.02-0.12 torr. The rate increased with [CO] at low CO pressures (< 0.02 torr)... 

The formation of a biradical, involving the addition of an oxygen atom to the double bond, is proposed to occur in the oxidation of acrylonitrile and crotononitrile by atomic oxygen( P). ... 

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