Separation manganese

Pirs and Magee have used the resin Amberlite IRA-400 in the chloride form to separate manganese, technetium, and rhenium. Manganese is easily separated by... 

An interesting reaction in which emeraldine is formed was observed by Caro [16]. If aqueous solution of free aniline is oxidised with potassium permanganate, and filtered from the separated manganese dioxide, the filtrate is a yellowish liquid, from which ether takes up a yellow amorphous eompound. This latter is converted into a green salt of emeraldine by mere contact with acids. A substance possessing the properties of emeraldine is formed simultaneously with quinone by oxidation of paramido-diphenylamine. A larger yield is obtained if this base is oxidised with an equivalent of aniline, and in this case quinone is not formed [17]. On further oxidation emeraldine yields a darker coloured compound, but it is doubtful if this is aniline black. The formation of emeraldine from paraphenylenediamine and diphenylamine leads to the supposition that it is a phenylated indamiue of the formula ... 

Sodium hydroxide quantitatively precipitates traces of Mn as Mn02aq., with Fe(lII), La, or Mg as carrier. Manganese can also be separated as Mn02aq. by treatment with excess of ammonia in the presence of H2O2. This method enables one to separate manganese from Ti, V, and other metals which form soluble peroxide complexes. 

As in the two-phase system, Mn(III) porphyrin is easily reduced by the conjugated Rh(III) complex in the presence of formate. In ethanol, complex 12 is capable of epoxidizing a-pinene with turnovers in the range of 300/h. The complex is much more stable under the applied reaction conditions than separate manganese porphyrin and rhodium bipyridine complexes and showed only a 10-20% loss of catalyst after 3h as followed by uv-vis spectroscopy. Further studies are being carried out to determine the scope and efficiency of this catalyst. 

Added reducing agent (reductant) and separated manganese dioxide (oxidant)... 

Suspend in a round-bottomed flask 1 g. of the substance in 75-80 ml. of boihng water to which about 0 -5 g. of sodium carbonate crystals have been added, and introduce slowly 4 g. of finely-powdered potassium permanganate. Heat under reflux until the purple colour of the permanganate has disappeared (1-4 hours). Allow the mixture to cool and carefully acidify with dilute sulphuric acid. Heat the mixture under reflux for a further 30 minutes and then cool. Remove any excess of manganese dioxide by the addition of a little sodium bisulphite. Filter the precipitated acid and recrystallise it from a suitable solvent (e.g., benzene, alcohol, dilute alcohol or water). If the acid does not separate from the solution, extract it with ether, benzene or carbon tetrachloride. 

Seaweeds. The eadiest successful manufacture of iodine started in 1817 using certain varieties of seaweeds. The seaweed was dried, burned, and the ash lixiviated to obtain iodine and potassium and sodium salts. The first process used was known as the kelp, or native, process. The name kelp, initially apphed to the ash of the seaweed, has been extended to include the seaweed itself. About 20 t of fresh seaweed was used to produce 5 t of air-dried product containing a mean of 0.38 wt % iodine in the form of iodides of alkah metals. The ash obtained after burning the dried seaweed contains about 1.5 wt % iodine. Chemical separation of the iodine was performed by lixiviation of the burned kelp, followed by soHd-Hquid separation and water evaporation. After separating sodium and potassium chloride, and sodium carbonate, the mother Hquor containing iodine as iodide was treated with sulfuric acid and manganese dioxide to oxidize the iodide to free iodine, which was sublimed and condensed in earthenware pipes (57). 

Eigure 3 is a flow diagram which gives an example of the commercial practice of the Dynamit Nobel process (73). -Xylene, air, and catalyst are fed continuously to the oxidation reactor where they are joined with recycle methyl -toluate. Typically, the catalyst is a cobalt salt, but cobalt and manganese are also used in combination. Titanium or other expensive metallurgy is not required because bromine and acetic acid are not used. The oxidation reactor is maintained at 140—180°C and 500—800 kPa (5—8 atm). The heat of reaction is removed by vaporization of water and excess -xylene these are condensed, water is separated, and -xylene is returned continuously (72,74). Cooling coils can also be used (70). 

The use of the Hquid-phase process in acetic acid with the cobalt— manganese—bromine system as explained in the tetephthaUc acid section is also possible (149). This process has been used by Amoco Chemical to produce pyromellitic acid, and facUities remain in place to do so again in the future. As with all hquid-phase oxidations of this type, yields ate high. A separate dehydration step would be needed to yield the dianhydtide. 

Concentration limits of the diphosphate-ion, admissible to determination of magnesium and cobalt, manganese and cobalt, zinc and cobalt by spectrophotometric method with application of the l-(2-pyridylazo)-resorcinol (PAR) are presented. Exceeding maintenance of the diphosphate-ion higher admissible supposes a preliminary its separation on the anionite in the H+-form. The optimum conditions of cobalt determination and amount of the PAR, necessary for its full fastening are established on foundation of dependence of optical density of the cobalt complex with PAR from concentration Co + and pH (buffer solutions citrate-ammoniac and acetate-ammoniac). 

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