SUBJECTS manganates

Early work of Dhar established that oxidation of oxalic acid by chromic acid occurs readily, but some of his kinetic data are unreliable as the substrate itself acted as the source of hydrogen ions. The reaction is first-order in oxidant and is subject to strong manganous ion catalysis (as opposed to the customary retardation), the catalysed reaction being zero-order in chromic acid. This observation is related to those found in the manganous-ion catalysed oxidations of several organic compounds discussed at the end of this section. 

The electronic properties of chiral catalysts were examined. Condensation of the optically active 1,2-diphenylethylenediamine with appropriate C5(5 )-substituted terf-butyl salicylaldehyde derivatives followed by complexation with mangane-se(III) center led to the corresponding catalysts 12a-12e. Then three model substrates, 2,2-dimethylchromene, cA-(3-methylstyrene, and cA-2,2-dimethyl-3-hexene, were subjected to enantioselective expoxidation catalyzed by 5-substituted... 

Manganate(VI) has also been the subject of research as in, for example, BaMn04 by Guerchais and co-workers (132) as well as Baran and Aymonino (35). This substance has a baryte structure with the MnOl" ions laying on lattice... 

Traces of chlorine are evolved but no manganate was found in the residue. J. G. Fowler and J. Grant found that only oxides which can form unstable higher oxides (Mn02, CrgOg, FcgOg, CuO) act catalytically. They confirmed the results of Hodgkinson and Lowndes. Some further researches on the subject have appeared since. ... 

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