Oxygen, migration

For the oxygen migration test for oxirene participation to be valid, it must be shown (80ZN(B)1040) that intermolecular oxygen transfer does not occur, and that oxygen scrambling... 

As rust accumulates, oxygen migration is reduced through the corrosion product layer. Regions below the rust layer become oxygen depleted. An oxygen concentration cell then develops. Corrosion naturally becomes concentrated into small regions beneath the rust, and tubercles are born. 

The simplest example of oxygen spillover is found in the adsorption of oxygen on carbon. The spillover oxygen migrates from the basal carbon (donor) to carbon atoms exposed at steps between layers of the graphite surface, where it reacts with the edge carbons (acceptor).71 In this case the donor and acceptor phase consist of the same material with different surface properties. 

The carbocations generated by non-Kolbe electrolysis can rearrange by alkyl, phenyl or oxygen migration. The migratory aptitudes of different alkyl groups have been studied in the rearrangement of a-hydroxy carboxylic acids (Eq. 34) [323]. 

Stereochemical features of 130 favor formation of a sulfurane dication 131 by treatment with concentrated sulfuric acid.132,133 The sulfuranyl dication 133 is postulated to be involved in the 1,5-oxygen migration observed in the reaction of monosulfoxide 132 with trifluoroacetic acid (Scheme 50).82... 

Pyrroline-A-oxide (258) is isomerized into y-lactam (259) in the presence of lithium diisopropylamine (LDA) (470) and sodium trityl (471). In these reactions, deprotonation at C3 occurs, leading to carbanion (260). Then oxygen migration from Ni to C2 takes place via intermediate formation of oxaziridine... 

Photochemistry of (2-nitrophenyl)diazomethane 70 has been studied by excitation at 350 nm in argon matrix isolation system54. That shows that at 10 K, 2-nitroso-benzaldehyde is formed by intramolecular oxygen migration from (2-nitrophenyl) carbene... 

A bis(dithia-dication) dimer has been proposed" " as an intermediate in the remote oxygen migration reactions of l,4-bis(methylthio)benzene and its derivatives (see... 

Several recent studies have shown the ease of oxygen migration to tin, OH groups from hydroxylic ligands 235) [Eq. (29)] as well as oxygen from nitro groups becoming bonded to tin (79) ... 

Light-catalyzed isomerization of azoxy derivatives to o-hydroxyazo-derivatives by exposure to sunlight, whereby the oxygen migrates from the nitrogen atom to which it is attached to the nucleus which is attached to the other nitrogen atom, seems to proceed via an intramolecular mechanism LXXVII I LXXX.12... 

Fig. 17. Scheme of the active oxygen migration through bulk diffusion in Bi2Mo,0 2/... 

A recently described oxygen migration reaction could proceed via a transition state incorporating a new chelate ring, but the actual mechanism is obscure (Scheme 69).177... 

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