Oxidation by peroxodisulfate

The peroxomonophosphate (PMS) oxidation of L-ascorbic acid (H2A), oxidation of indole, and the /H 50-tetraphenylporphyrin-FeCl3 (TPP)-catalysed oxidations of indole " and indole-3-acetic acid in HjO-MeCN are effected easily compared to the corresponding oxidations by peroxodisulfate. The catalysed reactions of indole and indole-3-acetic acid are of fractional order in both substrate and catalyst. The rate of oxidation of H2A is retarded by H" " ions. The rates of oxidation of indole and catalysed oxidation of indole 3-acetic acid decrease with increasing percentage of MeCN. 

The lower temperature treatment exhibited a lower elimination rate compared to that obtained at 70 C. The results obtained indicate that at low temperatures the peroxodisulfate produced on the BDD surface is not activated and the organic species are not oxidized by peroxodisulfate. 

In general, peroxomonosulfates have fewer uses in organic chemistry than peroxodisulfates. However, the triple salt is used for oxidizing ketones (qv) to dioxiranes (7) (71,72), which in turn are useful oxidants in organic chemistry. Acetone in water is oxidized by triple salt to dimethyldioxirane, which in turn oxidizes alkenes to epoxides, polycycHc aromatic hydrocarbons to oxides and diones, amines to nitro compounds, sulfides to sulfoxides, phosphines to phosphine oxides, and alkanes to alcohols or carbonyl compounds. 

The oxidation of 2-carboxyphenylacetic acid by peroxodisulfate ion is catalysed by Ag(I). The kinetics of the oxidation of tetrahydrofurfuryl alcohol by ditelluratocup-rate(III) and by ditelluratoargentateCin) in alkaline media have been studied. 

V, in acetonitrile with respect to the ferrocene/ferrocinium couple. " " Peroxodisulfate oxidation of [Fe(ttcn)2] does not give the Fe + complex the major product is [Fe(ttcn)(ttcn-1-oxide)]. Oxidation by lead dioxide does however yield [Fe(ttcn)2]. " The Fe—S bond... 

The best characterized positive oxidation state is AUV). Astatate ions may be formed by oxidation of At by peroxodisulf te, the ceric ion. or periodate ... 

The Mn(II)-catalysed oxidation of glucose by peroxodisulfate ions occurs via a radical-chain mechanism.26 Kinetics of oxidation of thiodiglycollic acid by (trans-cyclohexane-l,2-diaminc-/V, N, N, /V -tetraacetatolmanganateilJI) have been investigated.27 Oxidations of ketoses and aldoses by manganese(IV) in sulfuric acid media have a first-order dependence on sugar and fractional-order dependence on oxidant.28 A mechanism has been proposed for the oxidation of L-malic acid by Mn(III) pyrophosphate in aqueous acid, involving complex formation and radicals.29... 

Unsaturated 1,4-diketones are available from the corresponding nitro ketones by adsorption on silica gel," oxidation with peroxodisulfate or reduction with ascorbic acid (equation 38). 

The use of microwaves in the acceleration of digestion and colour development in the determination of total Kjeldahl nitrogen in soil has been examined [1]. Visual method based on the colour development of indothymol blue formed between ammonia and thymol has recently been developed for the determination of ammonia-nitrogen in environmental waters [2]. UV photo-oxidation of reduced forms of nitrogen to nitrate by peroxodisulfate can make a basis for the determination of total nitrogen in urban and industrial waste waters [3]. 

Pulse radiolysis shows that the pyrimidine radical cations are fairly strong acids and rapidly deprotonate at a heteroatom [reaction (98)]. As protonation/deprotonation reactions at heteroatoms are easily reversible, the radical cations are regenerated upon reprotonation. Deprotonation at carbon or reaction with water yields the final free-radical products [reactions (99) - (101)]. It is noted that in thymidine [23] and 5 -thymidylic acid [104] the allylic thymine radical is observed by EPR and there is very little question that its precursor is the thymine radical cation. The identification of the C(6)-OH-5-yl radical by EPR supports the view [100] that reaction with water competes with the deprotonation at methyl. Due to the ready oxidation of the (reducing) C(5)-OH-6-yl by peroxodisulfate, this type of radical is only observed at low peroxodisulfate concentrations in these systems, i.e. the (oxidizing) C(6)-OH-5-yl radicals are correspondingly enriched under conditions favourable to a chain reaction [22]. In the case of 1,3-dimethyluracil the interesting characteristics of... 

Simek ° reported that a solution of nickel(II) dimethylglyoximate in 1-2 mol dm KOH was easily oxidized by hypoiodite, hypobromite and peroxodisulfate to a solution containing a nickel(IV) complex. The complex K2[Ni (DMG)3] (DMG = dimethylglyoximate) has been prepared in aqueous alkaline medium from nickel(II) and DMG in the presence of two-electron oxidants such as CI2, OX (X = C1, Br, I), S2O8 or higher valent oxides of nickel. 

S Nishida, M Kimura. Kinetic studies of the oxidation reaction of arsenic (III) to arsenic (V) by peroxodisulfate ion in aqueous alkaline media. J Chem Soc Dalton Trans 2 357-360, 1989. 

Since in situ PEDT polymers are quite insoluble in most commonly used solvents, in situ PEDT cannot be easily made into a processable, coatable solution. However, an industrially usefiil form of oxidized PEDT can be made by aqueous oxidative polymerization of the EDT monomer in the presence of a template polymer, usually polystyrene sulfonic acid (PSS or PSSA). PSS is a commercially available water-soluble polymer and can thus serve as a good dispersant for aqueous PEDT. Polymerization with the oxidant sodium peroxodisulfate yields a PEDT PSS-complex in its conductive, cationic form (Figure 10.5). 

Several years ago we proposed a first structure model of the metallic core [28]. For this purpose, we examined seven different PAni powders that showed different conductivities and different dispersabil-ities. They were all prepared by principally the same procedure (water solution of aniline-p-toluene-sulfonate, which is oxidized by potassium peroxodisulfate), with identical monomer-oxidant ratios, but slightly differing reaction parameters. ... 

An acid-catalyzed pathway has been identified in the oxidation of iron (II) by peroxodisulfate by studying this well-characterized reaction over a wider acidity range. The oxidation of nitrilotriacetatocobalt(II) by this reagent has also been examined. Many reactions of peroxodisulfate are catalyzed by metal ions, through the formation of their higher oxidation states. However, doubts have been expressed over previous work that assigns this mechanism to the catalysis by Cu(II) of the malic acid-peroxodisulfate reaction. 

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