Persulfate anion

Water-soluble peroxide salts, such as ammonium or sodium persulfate, are the usual initiators. The initiating species is the sulfate radical anion generated from either the thermal or redox cleavage of the persulfate anion. The thermal dissociation of the persulfate anion, which is a first-order process at constant temperature (106), can be greatly accelerated by the addition of certain reducing agents or small amounts of polyvalent metal salts, or both (87). By using redox initiator systems, rapid polymerizations are possible at much lower temperatures (25—60°C) than are practical with a thermally initiated system (75—90°C). 

M.F. de Oliveira, R.J. Mortimer, and N.R. Stradiotto, Voltammetric determination of persulfate anions using an electrode modified with a Prussian blue film. Microchem. J. 64, 155-159 (2000). 

Studies into oxidative dimerization have shown that only the persulfate anion is of synthetic value in these reactions. Reaction pH is also crucial with reactions proceeding fastest when a pH of 7.2-9.4 is maintained. " The reaction medium becomes more acidic as the oxidation progresses and needs either buffering or the slow addition of alkali throughout the reaction. If the reaction medium is allowed to become acidic then the starting nitroalkane is regenerated and the Nef reaction predominates. 

N02-dG was achieved by the selective photodissociation of persulfate anions that generate 003 and N02 by one-electron oxidation of bicarbonate and nitrite anions in solution. " The 03 site-selectively generates G(—H) in the 11-mer that combines with N02 to yield the 8-N02-dG-adducted strand in 3% following HPLC purification. The nitrated 11-mer was stable at 4°C for 4 days, but depuri-nated at room temperature at pH 7 with a half-life of 20 h. " ... 

We have investigated the reactions of the COs " radicals with double-stranded DNA by laser flash photolysis techniques [15]. In these time-re-solved experiments, the COs radicals were generated by one-electron oxidation of HCOs by sulfate radical anions, SO4 the latter were derived from the photodissociation of persulfate anions, S20s initiated by 308-nm XeCl excimer laser pulse excitation. In air-equilibrated buffer solution containing the self-complementary oligonucleotide duplex d(AACGCGAATTCGCGTT), 208 , and an excess of HCO3., the decay of the CO3 radical anion absorption band at 600 nm is associated with the concomitant formation of the characteristic narrow absorption band of the G(-H) radicals near 310 nm. 

Diene substrate latices were prepared by seeding techniques following the scheme shown in Figure 1. Persulfate anion was the initiator, and an alkyl aryl sulfonate was the emulsifier. Reaction time varied between 13 and 33 hours. Since all the substrates were prepared by similar techniques, the volumetric swell index and gel gravimetric data (toluene) varied little with particle size. Small differences in swell and gel characteristics should not be a variable in this study because of the polarity of the grafting monomer mixture and rapidity of the graft reactions. 

A commonly used reactant in eel investigation is the persulfate anion S2Oi- [120,121], This strong two-electron oxidant is known [122,123] to react in two steps ... 

The photoinduced dissociation of persulfate anions [23] using light above 300 nm in wavelength is yet another method for generating reactive radical intermediates that can oxidize DNA [14, 32-35] ... 

Persulfate anion has the formula S2O7. Persulfates of sodium, Na2S207 [7775-27-1] ... 

Besides the excellent features of RU4POM as an OEC, its good performance in light driven water oxidation with [Ru(bpy)3] " as the photosensitizer is also ascribable to fast reaction kinetics of the electron transfer from the catalyst to the photogenerated oxidant (6). This was investigated by using [Ru(bpy)3], photochemically generated by [Ru(bpy)3] in the presence of persulfate anions [106]. In a typical nanosecond... 

The temperature dependence of the rate of persulfate anion reduction at the minimum of the polarization curve suggests that the activation energy dependst strongly on the nature of the cation and can even become negative in Cs solutions. Such behavior can be accounted for only by a preequilibrium with a negative enthalpy increment, the absolute value of which exceeds that of the true energy. Such a preequilibrium is provided by the formation of an ion pair on the surface. ... 

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