Peroxydisulfate system

Chemiluminescence determination of chlorpheniramine by use of tris(l,10-phenanthroline)-ruthenium(II) peroxydisulfate system and sequential injection analysis Spec determination of the complex after reducing Ru (IV) to Ru(II)... 

The oxidation of />-toluenesulfonic acid to the corresponding alcohol and aldehyde was achieved using the Shilov system and when employing oxidants other than Pt(iv), including peroxydisulfate or phosphomolybdic acid, only moderate turnovers were observed (Equation (18)).28... 

Oxidation may be achieved in the presence of oxygen or air. Other suitable oxidants include sulfur, sodium polysulfide, iron (III) chloride, potassium ferro-cyanide (III) or potassium dichromate, peroxydisulfate or salts of aromatic nitro-sulfonic acids. An aqueous/alkaline medium is used in the presence of a high boiling organic solvent which is not miscible with water or which is almost immiscible with water. Cyclization with chlorosulfonic acid can be followed directly by oxidation with bromine to afford the thioindigo system, without separation of the intermediate. 

The DCO oxidant may be electrochemically recycled. If the expended oxidant is not recycled, then the cost of DCO is estimated to be 79.00/kg of carbon destroyed. If the peroxydisulfate is recycled, then the energy cost is 4.00/ kg of carbon destroyed. The total cost of a DCO system using recycled oxidant was estimated to be 10.40/kg of carbon destroyed. These estimates include the cost of oxidant at 0.73/lb, the cost of electricity at 0.06/kWh, labor costs at 120 per day, and capital costs of 100,000. The full-scale unit was estimated to treat 50 kg of carbon per day with an online availability of 80%. The estimates do not include the additional costs of working in a nuclear environment, pretreatment, or stabilization and disposal of the final product (D18455Y, pp. 4, 5 D20886Q, p. 14 D20844G, p. 37 D21204U, p. 2). 

In spite of the abundant work on synthetic, thermodynamic, structural, and spectroscopic aspects of mixed-valence compounds, the dynamic solution behavior toward external redox reagents has not been much addressed. When such compounds are unsymmetrical and valence-localized, several problems arise when a fully reduced dinuclear complex reacts with an oxidant. Haim pioneered a systematic study performed with different systems reacting with a common two-electron oxidant, peroxydisulfate (126). A relevant example is given by reaction (35) ... 

ECL is obtained from these systems only when the potential of the working electrode is sufficiently negative that reduction of the transition metal complex occurs. In all cases peroxydisulfate will also be reduced at this potential. However, the S2O8 which reacts at the electrode does not participate in the ECL mechanism. Rather, it is the reaction of the reduced form of M with S2O8 - that initiates the luminescence process. The first two steps of this reductive oxidation ECL mechanism have therefore been proposed to be (6) ... 

This complex has been widely used in sensing applications since both radical ions of the complex are relatively stable to decomposition reactions. Many systems using this chromophore exist in which ECL is produced at a single electrode via coreactant oxidation or reduction schemes as discussed in the first segment of this section [Eqs. (5) through (9)]. For example, the reduction product of the peroxydisulfate dianion, S2Og, can function as an oxidant in the ECL reaction by annihilation with the electrochemically generated Ru1+ to yield the MLCT excited state of the Ru(II) complex by the mechanism [24] ... 

M7) be slow in some accessible range of pH and reactant fluxes. One oxidant which fails to enhance the range of constraints over which a chlorite-iodide system will oscillate is peroxydisulfate. In spite of its highly favorable reduction potential (E° = 2.01 V), S2Og reacts too slowly with I" in reaction (M4) to be a useful oscillatory substrate. 

Toluene has been oxidized by the silver ion catalysed reaction with peroxy-disulfate. The reaction produces a mixture of bibenzyl, benzaldehyde and benzoic acids.299 Russian workers have described the conversion of 4-methoxy-toluene to the benzaldehyde by oxidation with peroxydisulfate in the presence of silver or copper ions and oxalic acid.300 The presence of copper salts in iron or copper catalysed peroxydisulfate oxidation is believed to suppress side-reactions.301 Phillips have patented a palladium(II)/tin(IV)/persulfate system for the oxidation of toluene derivatives.302 The reactions are carried out in carboxylic acid solvents (Figure 3.78). 

A procedure was developed for the determination of total and labile Cu and Fe in river surface water. It involved simultaneous solvent extraction of the metals as diethyldithio-carbamates (ddc) and tfac complexes. The complexes were extracted by isobutyl methyl ketone (ibmk) and the solution subjected to flame atomic absorption spectrometry. Variables such as pH, metal complex concentration, reaction time, ibmk volume and extraction time were optimized. Prior to the solvent extraction a microwave-assisted peroxydisulfate oxidation was used to break down the metallorganic matter complexes in the river surface waters . Trifluoroacetylacetone was used as a chelation agent for the extraction and quantitative determination of total Cr in sea water. The chelation reaction was conducted in a single aqueous phase medium. Both headspace and liquid phase extractions were studied and various detection techniques, such as capillary GC-ECD, EI-MS (electron-impact MS) and ICP-MS, were tested and compared. The LOD was 11-15 ngL Cr for all the systems examined. The method provided accurate results with EI-MS and ICP-MS, while significant bias was experienced with ECD °. ... 

A third type of polymers is polymerized methyl methacrylate or methacrylamide (768-773), Strubell (768) has carried out polymerization of methyl methacrylate with an ascorbic acid-benzoyl peroxide system. In an aqueous polymerization of methyl methacrylate, Misra and Gupta (770) used the redox system of potassium peroxydisulfate and ascorbic acid. A similar system was reported by Pattnaik et al. (773). 

These authors describe the polymerization of acrylonitrile (AN), in systems in which peroxydisulfate ions S2Og, already present in the electrolyte, are decomposed following the well known reaction25 ... 

DIC, DOC Freshwaters UV irradiation for improving oxidation with peroxydisulfate in acidic medium UV—Vis 0.05 mg L 1 (both analytes) Sequential injection system UV irradiation for DOC determination inline C02 diffusion tandem stream with sample/digestion mixture segments [424]... 

Nitrogen( total) Wastewaters from urban waste water treatment plant Microwave-assisted oxidation of nitrogen-containing compounds to nitrate with an alkaline peroxydisulfate solution UV-Vis 0.21 mg L 1 Flow injection system chamber-like de- [434] bubbler for removal of the gaseous species formed during in-line oxidation nitrate reduction to nitrite Griess-Ilosvay reaction... 

Phosphorus (total) Waste waters, effluents Microwave-assisted digestion with an acidic peroxydisulfate solution UV—Vis 0.09 mg L 1 Flow injection system on-line filtration two microporous polypropylene tubes as de-bubblers orthophosphate detected as phosphomolybdenum blue [439]... 

Chang et al. also reported on the intercalation of aniline into zirconium phosphate sulfophenylphosphonate (ZPS), an organo derivative of a-zirconium phosphate [70]. The hydrophilic (—SO3H) groups in ZPS promote swelling of ZPS, which served as a template for aniline. The aniline-ZPS system was then oxidized with ammonium peroxydisulfate to yield a polyaniline-ZPS composite. However, there is no X-ray evidence that has been provided to support the formation of an intercalated phase. 

Nevertheless, cobaltous ions form efficient redox initiating systems with peroxydisulfate ions. " Tertiary aromatic amines also participate in bimolecular reaction with organic peroxides. One of the unpaired electrons on the nitrogen atom transfers to the peroxide link, inducing decomposition. No nitrogen, however, is found in the polymer. It is therefore not a true redox type initiation and the amine acts more like a promoter of the decomposition. Two mechanisms were proposed to explain this reaction. The first one was offered by Homer et al... 

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