Oxidation regeneration

The ferric sulfide can be oxidized with air to produce sulfur and regenerate the ferric oxide. The reaction for ferric oxide regeneration is as follows ... 

PhI(OTFA)2, CH3CN, H2O, 82-90% yield or PhI(OH)OTs, CDCI3, it, 2 h, 74-98% yield. Mild oxidative regeneration of ketones occurs in good yields. 

In a more limited study, Johnson (1974) studied the —S—S— pairing in the oxidative regeneration of reduced lysozyme peptide 57-83. By limited proteolysis and fractionation of the resultant pep-... 

That conclusion is supported and extended by the virtually simultaneous publication of Teale and Benjamin (1976). These investigators studied the oxidative regeneration of bovine serum albumin, assaying the extent of refolding immunochemically. Their results showed clearly that some parts of the molecule fold faster than others. Two fragments of albumin were tested for oxidative regeneration in the same way. Substantial return of native structure was seen in both fragments. 

FlC. 9. Nonparallel regeneration of the functions for bilirubin binding and fatty acid binding in bovine plasma albumin. The oxidative regeneration of reduced albumin was carried out at protein concentrations of 1 ft,M at 25°C in 0.10 M Tris-chloride buffer, pH 8.0, containing 1 mM EDTA and 1 mM reduced and 0.10 mM oxidized glutathione (Johanson et al, 1977, 1981). 

The formation of carbon-carbon bonds by palladium-promoted reactions has been widely used in organic synthesis [114-116]. A major advantage is that most of these coupling reactions can be performed with catalytic amounts of palladium. Palladium(II)-catalyzed reactions, e.g., the Wacker process, are distinguished from palladium(O)-catalyzed reactions, e.g., the Heck reaction, since they require oxidative regeneration of the catalytically active palladium(II) species in a separate step [117]. Several groups have applied palladium-mediated and -catalyzed coupling reactions to the construction of the carbazole framework. 

The basic features are delineated in a fundamental review , where the alleged R2N=0+ species is reported to be generated in situ by a suitable primary oxidant from precursor R2N—O (i.e. TEMPO). The substrate to be oxidized, e.g. an alcohol, attacks the oxoammonium ion as a nucleophile (Scheme 15) , giving an adduct that, by a-elimination, yields the carbonyl end product, while the primary oxidant regenerates the reactive R2N=0+ ion from the reduced R2NO—H (viz. TEMPOH) in a catalytic cycle. 

A related problem is the reduction in support surface area. This is especially a problem in the case of titania, where the anatase polymorph is only stable under oxidative regeneration conditions from about 400°C to 750°C. The addition of Si, Zr and Ta as promoter elements may avoid or diminish surface collapse of the support oxide. 

Ozone is applied in three-phase systems where a selective ozone reaction, oxidation of residual compounds and/or enhancement of biodegradability is required. It can be used to treat drinking water and waste water, as well as gaseous or solid wastes. Especially in drinking water treatment full-scale applications are common, e. g. for particle removal and disinfection, while in waste water treatment sludge ozonation and the use of catalyst in AOP have been applied occasionally. Current research areas for three-phase ozonation include soil treatment and oxidative regeneration of adsorbers. Ozonation in water-solvent systems is seldom studied on the lab-scale and seems favorable only in special cases. In general, potential still exists for new developments and improvements in ozone applications for gas/watcr/solvent and gas/waler/solid systems. 

In the oxidation of compounds sorbed on adsorbents, the appropriate treatment scheme should be evaluated on the basis of the oxidants used for regeneration. Perhaps the direct ozonation of pollutants in water is more favorable than a two stage process of adsorption followed by oxidative regeneration. However, if the pollutants are present in small concentrations in water, the enrichment by adsorption followed by ozonation in the sorbed state might be advantageous. 

Redispersion of Metals after Oxidative Regeneration - Influence of Wetting. -... 

Oxidative regeneration of NAD(P)+ cofactors can be accomplished by two general routes, see Fig. 37. NAD(P)H might act as an electron donor for an excited photosensitizer, thereby regenerating NAD(P)+ by a reductive ET quenching mechanism (Fig. 37 a). Alternatively, the oxidized photoproduct formed in an... 

Due to the volatility of some of the chlorides present the temperature must be maintained below 400 °C, which limits the scope for accelerating the rate-limiting oxidative regeneration step by increasing the temperature [19], For the unsteady-state adsorptive Deacon process the catalyst composition had to be modified to reduce volatility and enhance the oxidative of the reaction phase. 

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