Metal ion catalyzed oxidation

For a review of metal ion-catalyzed oxidative cleavage of alcohols, see Trahanovsky, W.S. Methods Free-Radical Chem. 1973, 4, 133. For a review of the oxidation of aldehydes and ketones, see Verter, H.S. in Zabicky The Chemistry of the Carbonyl Group, pt. 2 Wiley NY, 1970, p. 71. 

Hong, J., Lee, E., Carter, J. C, Masse, J. A., and Oksanen, D. A. (2004), Antioxidant-accelerated oxidative degradation A case study of transistion metal ion catalyzed oxidation in formulation, Pharm. Dev. Tech., 9(2), 171-179. 

As mentioned above, in metal ion-catalyzed oxidations many polymer-metal complexes have been found to exhibit high catalytic efficiency in comparison with their low-molecular-weight analogs. Table 12 summarizes the catalytic activity of the Cu complexes of synthetic polymers. It is noteworthy that high efficiency is observed for complexes composed of simple synthetic polymers arch as poly-(ethyleneimine), poly(vinylpyridine) and poly(acrylic add). 

If photographic materials are processed by developing solutions containing heavy metal ions, in particular iron(III) or copper ions, stains often occur. The addition of an inositolpolyphosphoric add to a color-developing solution complexes iron(III) ion, thereby preventing stain.86 In addition, aerial fog caused by heavy-metal ion catalyzed oxidation of the p-phenylenediamine color devel-... 

Stadtman, E.R. Metal ion catalyzed oxidation of proteins biochemical mechanism and biological consequences. Free Radical Biol. Med. 1990, 9, 315. 

In principle, the above selectivity problems can be avoided in suitably designed homogeneous metal-ion-catalyzed oxidation procedures. Transition metals, particularly those whose most stable oxidation states differ by 2e", often promote nonradical pathways even in the presence of dioxygen [6]. Moreover, since metal-carbon bond strengths parallel those of C-H bonds and because of steric factors, the preferential functionalization of primary C-H bonds becomes possible [7]. As a bonus, metal-ion catalyzed reactions usually operate at low temperatures (-100 °C or below) [8]. 

Metal ion-catalyzed oxidation of n-butane at 440-450 K and 50 atm is an important industrial process which gives acetic and formic acids along with low yields of methyl... 

It is difficult to estimate what the rate of the metal ion catalyzed oxidative deamination reaction of amino acids would be in natural waters. Hamilton and Revesz (30) found that the rate of oxidation of alanine in the presence of pyridoxal and manganese ions was inhibited by EDTA. Since metal ions in natural waters can be complexed by a variety of organic and inorganic compounds, their effectiveness in catalyzing the oxidative deamination of amino acids may be reduced. Also, the fraction of dissolved amino acids which would be complexed by metal ions at the pH and metal ion and amino acid concentrations found in natural waters must be considered. At neutral pH, where the amino group of the amino acid is protonated, the fraction of the amino acid that would be in the form of the metal ion complex depends upon the equilibrium constant for the formation of the complex and the pK of the amino proton of the amino acid. The reactions for the formation of the Cu2+-alanine complexes can be written as... 

The rate constant for the metal ion catalyzed oxidative deamination of an amino acid when only a fraction of the amino acid is chelated is given by... 

Belisario MA, Di Domenico C, Pelagalli A, Della MR, Staiano N. Metal-ion catalyzed oxidation affects fibrinogen activity on platelet aggregation and adhesion. Biochimie 1997 79 449-55. 

E. R. Stadtman, Metal Ion-Catalyzed Oxidation of Proteins Biochemical Mechanism and Biological Consequences (R), Free Radicals in Biology Medicine 9 (1990), 315—325. 

Brimblecombe, P., and D. J. Spedding (1974a). The reaction of the metal ion catalyzed oxidation in aqueous solution. Chemosphere 1, 29-32. 

B) The elementary reaetions in the reaetion mechanism represent the various reactions involved in the oxidation of SO2 to H2SO4 in three main reaction pathways, namely, (i) direct oxidation of SO2, (ii) metal-ion-catalyzed oxidation of SO2 to H2SO4, and (iii) photochemical oxidation of SO2 to H2SO4 hy means of oxidants such as hydroxyl radical and ozone. Once formed, the H2SO4 will react readily with NH3 to form the ammonium sulfate haze crystals. All three of these reaction pathways are operative in the DUV (193-nm and 248-nm) exposure tools, and the interplay between them as they react with photons and ultimately with NH3, as well as the concentration of the reactants at each point in time, are responsible for the progressive growth nature of these haze crystals. 

Traces of metals are present in most polymers as a result of processing in stainless steel reaction vessels, being transported in metal containers and shaping in metal moulds or rolling between metal rollers. Many metal ions catalyze oxidation by accelerating decomposition of hydroperoxides at room temperature. Observation of plastics materials in museums suggests that copper is a highly effective catalyst for semi-synthetic materials such as cellulose nitrate and... 

However, the limit for the use of DMC in industrial practice was in its preparation, far from eco-friendly, that involved the reaction of methanol with phosgene. Among the alternative phosgene-free routes to DMC considered in the last two decades, the most attractive is the metal ion-catalyzed oxidative carbonylation of methanol, set up by EniChem in 1983 (2). This technology is now currently used in the industry for the production of DMC. 

In addition, many of the organosulfur compounds and organometallic compounds used in rubber compounds as vulcanization accelerators are known to have antioxidant activity. Mercaptobenzimidazole and its zinc salt have been shown to have antioxidant activity. In addition, mercaptobenzimidazole, when combined with other known antioxidants, has been shown to have a synergistic effect in oxidation prevention when metal ion catalyzed oxidation is prevalent. Also, metal and amine salts of dialkyldithio-carbarnates have been shown to have antioxidant action. 

The metal ion catalyzed oxidation of aldehydes to carboxylic acids has been extensively studied and a free-radical chain mechanism is now firmly established. The acylperoxy radical intermediate has been utilized for converting olefins to epoxides. 

Buffle, j., and A. E. Martell Metal Ion Catalyzed Oxidation of o-Dihydroxy Aromatic Compounds by Oxygen. 1. Inorgan. Chem. 16, 2221 (1977). 

The reaction is actually a group of reactions that have some common ingredients. Generally, a BZ reaction is the metal-ion-catalyzed oxidation of certain carboxylic acids by bromate (Br03 ) ions. A common catalyst is the cerium(IV) ion, Ce. One example of an overall reaction is... 

This section covers metal ion catalyzed oxidative cleavage of DNA and polydeoxyribonucleotides. Table 21 gives detailed data on rate, specificity and mechanism in a range of systems. 

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