Potassium manganate, oxidation

Silanes are very sensitive to attack by alkalis and will even react with water made alkaline by contact with glass this reaction is in marked contrast to the reactions shown by alkanes. Unlike alkanes, silanes are found to have marked reducing properties and will reduce, for example, potassium manganate(VII) to manganeseflV) oxide, and iron(III) to iron(II). 

The product is a solid yellow hydrated oxide. If prepared by a method in the absence of water, a black anhydrous product is obtained. Germanium(II) oxide is stable in air at room temperature but is readily oxidised when heated in air or when treated at room temperature with, for example, nitric acid, hydrogen peroxide, or potassium manganate(VII). When heated in the absence of air it disproportionates at 800 K ... 

Oxygen can be produced by certain reactions in solution, for example the oxidation of hydrogen peroxide by potassium manganate(VII) acidified with sulphuric acid ... 

This oxide is obtained by adding potassium manganate(VII) to concentrated sulphuric acid, when it appears as a dark coloured oil which readily decomposes (explosively on heating) to manganese(IV) oxide and oxygen ... 

Excess standard acid is added, and the excess (after disappearance of the solid oxide) is estimated by titration with standard potassium manganate(VII). 

The raw potassium manganate(VI) from the secondary roaster or the Hquid-phase oxidizer contains a fair amount of insoluble material such as unreacted MnO and ore gangue. In most continuous processes, these insolubles are removed by sedimentation using thickeners or filtration and are disposed of as waste. 

The Stock Oxidation-Number System. Stock sought to correct many nomenclature difficulties by introducing Roman numerals in parentheses to indicate the state(s) of oxidation, eg, titanium(II) chloride for TiCl2, iron(II) oxide for FeO, titanium(III) chloride for TiCl, iron(III) oxide for Fe203, titanium(IV) chloride for TiCl, and iron(II,III) oxide for Fe O. In this system, only the termination -ate is used for anions, followed by Roman numerals in parentheses. Examples are potassium manganate(IV) for K2Mn02, potassium tetrachloroplatinate(II) for K PtCl, and sodium hexacyanoferrate(III) for Na3Fe(CN)3. Thus a set of prefixes and terminations becomes uimecessary. 

When heated with potassium hydroxide, manganese(IV) oxide partially decomposes to manganese(lll) oxide and potassium manganate ... 

Potassium manganate obtained above is oxidized to the permanganate either by electrolysis or by chemical oxidation. Electrolytic oxidation is more common. Electrolytic cells have cathodes made of iron rods and nickel-plated anodes. Potassium manganate melt is extracted with water prior to its electrolysis and then electrolyzed at a cell voltage of 2.3V and current of about 1,400 amp. Permanganate is produced at the anode and water is reduced to gaseous hydrogen and hydroxyl ions at the cathode ... 

The vendor claims that using ozone to treat a 1-acre site contaminated with 1 part per million (ppm) trichloroethene (TCE) would cost approximately 269,000. This estimate assumes 20 ft of thickness. Treating the same site using alternative oxidants would be less expensive. Hydrogen peroxide would cost about 201,000, sodium manganate would cost about 187,000, and potassium manganate would cost about 136,000 (D203816, p. 6). 

Preparation of Potassium Manganate. Melt a mixture of 1 g of potassium hydroxide, 2 g of potassium carbonate, and 3 g of potassium nitrate in an iron crucible on a gas burner. While stirring the liquid mixture with an iron wire, add 1 g of powdered manga-nese(IV) oxide in small portions. Continue the heating while stirring until the substance becomes thick. After it cools, treat the melt in the crucible with a small amount of water. Pour off the transparent solution into a small flask and close it with a stopper keep the substance remaining in the crucible for the following experiment. What is the colour of the solution What substance colours it Write the equation of the reaction. 

Diethyl ketone was either purchased from the Eastman Kodak Company and redistilled, or prepared by passing propionic acid slowly over a mixture of manganous oxide and clay plate chips in a tube furnace at 420-440° 3 the apparatus was similar to one described in Organic Syntheses When prepared by this method the ketone was distilled, dried over potassium carbonate, and redistilled b.p. 100-101°. 

Following the initial report by Reichstein and Griissner 1 on the oxidation of 26 to 27, a number of other methods using potassium permanganate or related manganese salts (such as potassium manganate) as the oxidant, under a variety of different conditions, appeared.114,115,... 

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