Persulphate oxidation

Siher(Il) oxide, AgO, is a black solid, Ag Ag 02, obtained by anodic or persulphate oxidation of an AgNOs solution. Continued anodic oxidation gives impure Ag203. Argentates, e.g. K.AgO, containing silver(I) are known. 

The longest established silver(III) complexes are the red to brown bi-guanides, like the ethylene bis(biguanide) shown in Figure 4.14 persulphate oxidation of Ag+ in the presence of this ligand gives a silver(III) complex with essentially square planar coordination. 

Cu(II) also catalyses the persulphate oxidation of numerous substrates, for example that of oxalate-ion with a rate law ... 

As mentioned above, many variants of the Dohrmann total organic carbon analyser are available, ranging from low-cost non-automated analysers based on sample combustion in a platinum boat (DC8JA) or using persulphate oxidation/ultraviolet irradiation (DC 88) to top-of-range fully automated and computerized systems based on combustion in a ceramic tube (DC 90) or combined simultaneous persulphate-ultraviolet oxidation (DC 180). Only one of these systems, the DC 180, is discussed below in any detail. 

In the reactor combined UV persulphate oxidation ensures quantitative total organic carbon recovery. The resulting carbon dioxide with entrained water goes through a gas/liquid separator, a water trap and drier before it... 

OIC Analytical instruments produce the fully computerized model 700 total organic carbon analyser. This is applicable to soils and sediments. Persulphate oxidation at 90-100°C non-dispersive infrared spectroscopy is... 

The persulphate oxidation technique [25] has been applied to estuarine sediments. Organic carbon was determined at lOg kg-1 in bay and estuarine sediments with a coefficient of variation of about 10%. 

With the preformed ammonium persulphate, oxidation of sulphides to both sulphoxides and sulphones has been observed [e.g. 6, 7] whereas, when Oxone is used in conjunction with a quaternary ammonium salt, oxidation can be selectively stopped at the sulphoxide stage [6-8]. It has been recorded that electron-deficient aryl sulphides, e.g. di(4-nitrophenyl)sulphide, are not readily oxidized. 

Morgan. L. B. Transient molecular species occuring in persulphate oxidations. Trans. Faraday Soc. 42, 169—183 (1946). 

Rossi, G. and M. Savarese. 1997. On-line determination of total nitrogen in natural sea water samples by alkaline persulphate oxidation. Mar. Pollut. Bull. 35 174—175. 

Yield of Coupling Products from Kolbe and Persulphate Oxidation of t-BuCH(R)COO in Aqueous Medium0... 

The role of [Mn(bpy)3]2+ as an oxidation catalyst suggests the possible involvement of Mn(III) complexes, but no successful synthesis of [Mnibpyls] salts has yet been reported. Electrochemical studies indicate that [Mn(bpy)3]2+ salts undergo an irreversible oxidation at moderately positive potentials (403, 646). In the presence of water, the product of the oxidation is the dimeric complex ion [(bpy)2Mn02Mn(bpy)2] (646), which is also obtained from persulphate oxidation of [Mn(bpy)3] + (687). 

One simple example of much-preferred para attack is in the Elbs persulphate oxidation of phenol. The reaction is usually written as the combination of a phenoxy radical (414) with the radical anion (415), but it could be phenoxide ion undergoing electrophilic substitution in any event, para attack is favoured over ortho attack by a factor of about 20 1.335... 

With persulphate as oxidant, it is necessary to add a small amount of Ag(I) or Co(II) ions to catalyse the reaction. The oxidation of manganese with periodate or persulphate is carried out in sulphuric acid or nitric acid, or in a mixture of the two. The concentration of the acid affects the rate of oxidation of Mn(ll). With KIO4, higher concentrations of H2SO4 and HNO3 can be used than with (NH4)2S208. Periodate oxidation yields a more stable solution of Mn04 than does persulphate oxidation. 

Turbidity (AgCl) caused by traces of chloride present during silver-catalysed persulphate oxidation is prevented by the addition of a little mercury(II) sulphate [a stable complex, HgCL, is formed in the presence of Hg(ll)]. The mechanism and the conditions of Mn(ll) oxidation by persulphate in the presence of Ag(I) ions have been studied [11]. 

Sharp, I.H., 1973a. Total organic carbon in sea water — comparison of measurements using persulphate oxidation and high temperature combustion. Mar. Chem., 1 211— 229. 

Dissolved organic carbon was analysed using a Skalar 12 instrument. The method is based on UV-persulphate oxidation and described in detail in Appendix 4. The DOC of every sample was measured as a routine analysis. 

The quantitative reliability of inductively coupled plasma high-resolution mass spectrometry for phosphorus determinations was judged by comparing it to the standard total filterable phosphorus method (Gooper et al., 1999). That method includes a persulphate oxidation step to convert all forms of phosphorus to phosphate, which is then suitable for the molybdenum blue reaction. Using the same set of standards, calibration curves for both methods were developed over a range of 0-200 pg P/1. Fig-... 

A persulphate oxidizing agent for the decomposition of organic material containing N and P is commercially available (Oxisolv, Merck). 

Detennination of total and organic phosphorus by add persulphate oxidation... 

Die methodology of alkaline, borate buffered persulphate oxidation (Korolejf, 1977), is also applicable to the decomposition of suspended sUicon.Die procedure given here is similar to that for total phosphorus (see Section 10.2.14), i.e., the sample is autoclaved with per-oxodisulphate at pH 9.7 in the beginning and at about 5 at the end of the oxidation. Silicate is then determined according to Section 10.2.11. 

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