Manganese complexes oxalates

A PRP -1 (Hamilton Reno, NV) reversed phase column was coated with cetylpyridinium and eluted with tetramethylammonium salicylate acetoni-trile water.89 The separation was comparable to that observed on conventional ion exchange. Coated phases were also used to separate oxalate complexes of manganese, cobalt, copper, and zinc.90 Reversed phase silica supports were coated with poly(N-ethyl-4-vinylpyridinium bromide), poly(dimethydiallylammonium chloride), poly(hexamethyleneguanidinium... 

Reaction 5. Another aspect of the reaction chemistry of Mn(III) is demonstrated by the classic kinetic studies of the decomposition chemistry of manganese (III) oxalate complexes (35, 36). These studies derive from an earlier discussion of the synthesis of manganese (III)-oxalate compounds (37). A similar set of kinetic and synthetic investigations, have been summarized for the manganese (III )-malonate complexes (38, 39). Both sets of studies confirm that Mn(III) has a particularly strong... 

The oxalate [Mn(C204)3], like the catecholate [Mn(cat)3] compounds, can be readily oxidized to Mn state. Otherwise, oxalate can form polymers and the combination of phosphate and oxalate in fomting hybrid framework materials has been also explored. Several hydroxycarboxylates exist as monomers or polymers and the first mononuclear manganese citrate complex, (NH4)4[Mn(C6H507)2], has been recently isolated and crystallographically characterized. ... 

Manganese ions interfere (oxidized to permanganate) as do also mercury(II) salts, molybdates, and vanadates, which give blue to violet compounds with the reagent in acid solution. The influence of molybdates can be eliminated by the addition of saturated oxalic acid solution thereby forming the complex H2[Mo03(C204)]. 

Various chemical extraction techniques have been introduced in order to selectively remove metals from the different adsorption or complexation sites of natural sediments (e.g., Tessier et al, 1979 Erel et al, 1990 Leleyter et al., 1999). It is, for example, shown by Leleyter et al. (1999) that between 20% and 60% of REE in various suspended river sediments are removed by successive extractions by water, by Mg(N03)2 (exchangeable fraction), sodium actetate (acid-soluble fraction), NH2OH - - HCl (manganese oxide dissolution) ammonium oxalate (iron oxide dissolution) and a mixture of H2O2 + HNO3 (oxidizable fraction). The complexity of... 

Method 13 describes the generation of amorphous manganese oxide (AMO) materials that are made by the complexation of oxalic acid with KMn04. This reaction is done at SO C and leads to an amorphous gray black powder. The chemical and physical properties of AMO are very different than all the other materials listed in Table IV. K+ ions are incorporated into AMO due to reduction of Mn + ions. Analytical data suggest that some unreacted oxalic acid is incorporated into the AMO powder. This suggests that some Mn4- ions are reduced to Mn3+ creating a mixed valent species, as is the case for OL-1,... 

The reaction between permanganate ion and oxalic acid is complex and proceeds slowly even at elevated temperature unless manganese(II) is present as a catalyst. Thus, when the first few milliliters of standard permanganate are added to a hot solution of oxalic acid, several seconds are required before the color of the permanganate ion disappears. As the concentration of manganese(ll) builds up, however. the reaction proceeds more and more rapidly as a result of autocatalysis. 

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