Manganous-chromium oxide

Westheimer has also reviewed the induced oxidations by the Cr(VI)-As(III) couple of iodide, bromide and manganous ions vide supra). The induction factor of 0.5 for Mn(II) implies an intermediate tetravalent chromium species however, the factor of 2 for iodide points to a pentavalent chromium intermediate. Both... 

The oxidation of tartaric and glycollic acid by chromic acid also induces the oxidation of manganous ions. In the presence of higher concentrations of manganese(II) the rate of oxidation of the acids is diminished to about one-third of that in the absence of manganous ions. The decrease of the rate has been attributed to manganese(II) catalysis of the disproportionation of the intermediate valence states of chromium probably chromium(IV). 

In order to balance mineral intake, the following minerals were used in place of the usual mineral mix (% of diet) potassium chloride, 0.32 magnesium oxide, 0.084 manganous carbonate, 0.0123 ferric nitrate, 0.021 zinc carbonate, 0.0056 cupric carbonate, 0.0011 potassium iodate, 0.0004 sodium selenite, 0.00003 chromium potassium sulfate, 0.00193. 

They form more complicated ions with high oxidation states. For example, chromium forms the dichromate(vi) ion, Cr2072-, which contains chromium with a +6 oxidation state (Cr(vi)) and manganese forms the manganate(vu) ion, Mn04, which contains manganese with a +7 oxidation state (Mn(vn)). 

Chromium (VI) oxide Halogens/Halogenating agents Hydrogen peroxide Manganates (VII)... 

OXIDATION, REAGENTS Barium mangan-ate. Benzyl(triethyl)ammonium permanganate. Bispyridinesilver permanganate. Bis(trimethylsilyl)peroxide. t-Butyl hydroperoxide. t-Butyl hydroperoxide-Benzyltri-methylammonium tetrabromooxomolyb-dale. t-Butyl hydroperoxide-Bisoxobis-(2,4-pentadionato)molybdenum. t-Butyl hydroperoxide-Chromium carbonyl. t-Bu-tyl hydroperoxide-Dialkyl tartrate-Titan-ium(IV) isopropoxide. t-Butyl hydroper-... 

Oxidation of aromatic systems containing alkyl side-chains results in the formation of a carboxylic acid, irrespective of the length of the side-chain. The usual oxidizing agents are potassium permanganate [potassium manganate(VII)] or chromic acid [chromium(VI) acid]. For example, 1,4-dimethylbenzene is oxidized to benzene-1,4-dicarboxylic acid (tereph-thalic acid, 9), an important building block for polyesters. The oxidation of isopropylbenzene (cumene) to phenol is an important industrial process and is discussed in Chapter 4. 

Oxidation reactions in the hot zone are probably responsible for the large yield of Cr(VI) obtained in the positron decay of Mn to Cr in crystals of cesium permanganate (11). Manganous ion in solution yielded only chromic ion, whereas in crystals of MnCOs, 30% of the chromium recoils appeared as Cr(VI). This probably occurred as a result of reactions between chromium recoils and debris oxygen atoms or carbonate ions. 

The oxidation of diols having alcoholic groups of the same nature, for example, both alcoholic groups are primary, secondary, allylic, or benzylic, is usually carried out at both groups to yield dialdehydes [832] or diketones [552], Such reactions are achieved by chromium trioxide [582], barium manganate [832], dimethyl sulfoxide activated with acetic anhydride [1013], and others (equations 284 and 285). 

P.E. Childs and J.B. Wagner Jr., Chemical diffusion in wustite and chromium-doped manganous oxide, in G.R. Beltane and W.L. Worrell (Eds.), Heterogeneous Kinetics at Elevated Temperatures. Plenum Press, New York, 1970, pp. 269-342. 

Fio. 11. The rate constant logarithm aa a function of the temperature reciprocal in the oxidation of iso-octane over various catalysts 1—copper chromium, 2—copper chromite, 3—platinum, 4—copper aluminum and iron-aluminum, 6—silver manganate, 6—iron-chromium, 7—magnesium chromite, 8—copper chromium with addition of PbO. 

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