Peroxodisulfate oxidant

The kinetics formation of [Ni([9]aneN3)2]3+ have been studied in great detail. Inter alia, the volume of activation for peroxodisulfate oxidation of [Ni([9]aneN3)2]2+ has been determined (—25.8 2.3 cm3 mol 1),105 and the kinetics of this reaction have been determined as a function of peroxodisulfate concentration and temperature.106 The reaction is first-order in both reagents (second-order rate constant 1.13 mol dm 3 s 1 at 298 K), and the activation energy is 38 1.8 kJ mol-1. In mixed solvents, the rate is slower. 

Shepherd and Davies [26] have described a semiautomated version of the alkaline peroxodisulfate procedure for the determination of total dissolved organic nitrogen in seawater. These workers carried out experiments on a range of contaminated and clean seawaters using a version [27] of Koroleff s [24] alkaline peroxodisulfate oxidation technique. 

The activation volume for peroxodisulfate oxidation of [Fe(CN)5(pentylpz)] , 0 2cm moF suggests, as do the close-to-zero values for analogous reactions of [Fe(CN)6j" and of [Fe(diimine)(CN)4], compensation between intrinsic and solvational contributions." ... 

Activation volumes for dissociation, base hydrolysis, cyanide attack, and peroxodisulfate oxidation (see following pages) of iron(II)-diimine complexes are collected together in Table 9. 

Temperature and pressure effects on rate constants for [Fe(phen)3] +/[Fe(phen)3] + electron transfer in water and in acetonitrile have yielded activation parameters AF was discussed in relation to possible nonadiabaticity and solvation contributions. Solvation effects on AF° for [Fe(diimine)3] " " " " half-cells, related diimine/cyanide ternary systems (diimine = phen, bipy), and also [Fe(CN)6] and Fe aq/Fe aq, have been assessed. Initial state-transition state analyses for base hydrolysis and for peroxodisulfate oxidation for [Fe(diimine)3] +, [Fe(tsb)2] ", [Fe(cage)] " " in DMSO-water mixtures suggest that base hydrolysis is generally controlled by hydroxide (de)hydration, but that in peroxodisulfate oxidation solvation changes for both reactants are significant in determining the overall reactivity pattern. ... 

Reaction kinetics and mechanisms for oxidation of [Fe(diimine)2(CN)2], [Fe(diimine)(CN)4] (diimine = bipy or phen) (and indeed [Fe(CN)6] ) by peroxoanions such as (S20g, HSOs", P20g ) have been reviewed. Reactivity trends have been established, and initial state— transition state analyses carried out, for peroxodisulfate oxidation of [Fe(bipy)2(CN)2], [Fe(bipy)(CN)4] , and [Fe(Me2bsb)(CN)4] in DMSO—water mixtures. Whereas in base hydrolysis of iron(II)-diimine complexes reactivity trends in binary aqueous solvent mixtures are generally determined by hydroxide solvation, in these peroxodisulfate oxidations solvation changes for both partners affect the observed pattern. ... 

Kinetics of peroxodisulfate oxidation of [Fe(terpy)(CN)3] in water and in binary aqueous solvent mixtures have been analyzed, with the aid of measured solubilities of [Ph4As][Fe(terpy)(CN)3], to separate the initial state and transition state contributions to the observed reactivity trend. ... 

Peroxodisulfate oxidation of 3,14-dimethyl-4,7,10,13-tetraazadeca-3,13-diene-2,5-dionedioxima-toiron(II) proceeds by electron transfer within a preformed ion pair. " The electrochemistry of [Fe (dmgH)2(imH)2], with the kinetics of its autooxidation (catalyzed by Cu but inhibited by... 

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 neutral complexes Nil or NiL2B2 (B = py or ibipy) have been conveniently synthesized by reacting the quinone ligand and Ni(CO)4 in apolar solvents (n-pentane, n-hexane, benzene).1 0,1601 The use of anaerobic conditions gives the best results. In one case, that of Ni(C6H402)2, the complex was obtained by the peroxodisulfate oxidation of an aqueous solution of nickel(II) acetate and pyrocatechol. 

To remove the sulfate introduced during the peroxodisulfate oxidation, the crude product is dissolved in a minimum amount of 1 M hydrochloric acid ( 160 ml.) at 40°C., and barium chloride (3 g.) dissolved in a minimum amount of hot water is added. The solution is allowed to stand for 20-30 minutes, rewarmed to 50°C., and the barium sulfate filtered off on a medium-porosity sintered-glass filter. Concentrated hydrochloric acid (20 ml.) is added to the filtrate, which is cooled until precipitation is complete. The solid is recrystallized by dissolving it in a minimum amount of 0.1 M hydrochloric acid... 

The presence of Ir02 nanoparticles on the BDD surface causes a considerable decrease in the overpotential for oxygen evolution, in the inhibition of sulfate to peroxodisulfate oxidation, and in the modification of the mechanism of organic oxidation. 

Diphenylamine in aqueous Triton X-100 medium was applied to determine Ag in photographic print paper [3]. The catalytic effect of Ag on the peroxodisulfate oxidation of Brilliant Cresyl Blue with 1,10-phenanthroline as activator makes the basis of the determination of Ag in river water [4]. 

Kinetic spectrophotometric determination methods for Ag(I) were proposed, based on the strong catalytic effect of this ion on the controlled oxidation of various dyes, by measuring the rate of change of absorbance. Some recently published examples are Ag(I)-catalyzed peroxodisulfate oxidation of brilliant cresyl blue (33)104 or gallocyanine (34)105, both in the presence of 1,10-phenanthroline (35) and hexacyanoferrate (36) oxidation of indigo carmine (37)106. 

Kinetics of aquation, base hydrolysis, cyanide attack, and peroxodisul-fate oxidation have been investigated for the 4-methyl-1,10-phenanthroline complex [Fe(4Me phen)3]. The main interest here is that another demonstration is provided of the dominant role of solvation changes in determining activation volumes when heavily solvated ions, such as cyanide here, are involved. The minimal change in AF on going from water as solvent to 33% methanol is also ascribable to heavy and strongly preferential hydration of the cyanide. " In a similar vein, the zero activation volume for peroxodisulfate oxidation of the [Fe(bipy)(CN)4] anion, surely simple bimolecular outer-sphere electron transfer, can also be explained by balanc-... 

Rate-determining steps leading to I(IV) and I(III) are postulated, with subsequent rapid reduction of intermediate iodine species. An induction period followed by oxidation of the [Fe(phen)3] complex is a feature of the reaction of that complex with bromate ions. The rates of the corresponding reactions with CI2 and affected by Cl", Br", or hydrogen ion. The oxidations occur via the one-electron transfer steps and an analysis of the data and those for other metal ion reductants has been made using a Marcus theory approach. The kinetics of the peroxodisulfate oxidation of two [Fe(II)(a-diimine)3] complexes have been investigated in binary aqueous-solvent mixtures.The rate data have been dissected into initial and transition state energies. Comparisons between the relative contributions to these parameters for redox and substitution reactions remain a topic of interest. 

Hence for this oxidant and substrate, the sole reaction path is by initial ratedetermining dissociation/This situation parallels that reported for peroxodisulfate oxidation of the maleonitriledithiolato-cobalt(II) complex,and for peroxodiphosphate oxidation of low-spin iron(II) complexes/ Substitution processes also appear to play a small part in the complicated reaction mechanism for cerium(IV) oxidation of tris[2-pyridinal-a-methyl(methylimine)]iron(II), the low-spin iron(II) complex of the Schiff base 22, an aliphatic analog of 21/ ... 

For instance, peroxodisulfate oxidizes metiiane to alcohols in the absenee of a metal at 105-115°C. Metal complexes ean be used as mediators for such reactions which permits carrying out the reactions at lower reaction temperatures. - In the ease of cycloalkanes, strongly electrophilic and oxidizing transition-metal ions play an irreplaceable role in the initiation step. 

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