Potassium permanganate, reaction

Isothiochromanone is easily oxidized to its potassium permanganate. Reactions of this sulfone are shown in Scheme... 

Chakactkrisation of Unsaturatkd Aliphatic Hydrocarbons Unlike the saturated hydrocarbons, unsaturated aliphatic hydrocarbons are soluble in concentrated sulphuric acid and exhibit characteristic reactions with dUute potassium permanganate solution and with bromine. Nevertheless, no satisfactory derivatives have yet been developed for these hydrocarbons, and their characterisation must therefore be based upon a determination of their physical properties (boiling point, density and refractive index). The physical properties of a number of selected unsaturated hydrocarbons are collected in Table 111,11. 

A somewhat lower yield is obtained if all the potassium permanganate (150 g.) is added all at once and, furthermore, the reaction may become violent. Addition in three portions results in a more controllable reaction. 

Sahcylaldehyde is readily oxidized, however, to sahcyhc acid by reaction with solutions of potassium permanganate, or aqueous silver oxide suspension. 4-Hydroxybenzaldehyde can be oxidized to 4-hydroxybenzoic acid with aqueous silver nitrate (44). Organic peracids, in basic organic solvents, can also be used for these transformations into benzoic acids (45). Another type of oxidation is the reaction of sahcylaldehyde with alkaline potassium persulfate, which yields 2,5-dihydroxybenzaldehyde (46). 

The MauIg Color Reaction. The procedure for this test consists basically of three sequential treatments of lignified material with 1% potassium permanganate, 3% hydrochloric acid, and concentrated ammonium hydroxide. A red-purple color develops for hardwoods and a brown color... 

The brown crystalline manganese(III) acetate dihydrate is of considerable commercial importance because it is often used as the source material for other trivalent manganese compounds. It can be made by oxidation of manganese(II) acetate using chlorine or potassium permanganate, or by reaction of manganese(II) nitrate and acetic anhydride. 

Aqueous potassium permanganate solutions are not perfectiy thermodynamically stable at 25°C, because Mn02, not MnO is the thermodynamically stable form of manganese in water. Thus permanganate tends to oxidize water with the evolution of oxygen and the deposition of manganese dioxide, which acts to further catalyze the reaction. 

The kinetics of the reaction are relatively slow and permanganate solutions exhibit greatest stabiUty around a neutral pH. The decomposition rates increase below pH 3 or above pH 10. Potassium permanganate solutions are stable at elevated temperatures, up to approximately 3 N sodium hydroxide, above which decomposition into manganate occurs. 

Oxidation Reactions. Potassium permanganate is a versatile oxidizing agent characterized by a high standard electrode potential that can be used under a wide range of reaction conditions (100,133—141). The permanganate ion can participate in a reaction in any of three distinct redox couples. 

The use of sofid supports in conjunction with permanganate reactions leads to modification of the reactivity and selectivity of the oxidant. The use of an inert support, such as bentonite (see Clays), copper sulfate pentahydrate, molecular sieves (qv) (151), or sifica, results in an oxidant that does not react with alkenes, but can be used, for example, to convert alcohols to ketones (152). A sofid supported permanganate reagent, composed of copper sulfate pentahydrate and potassium permanganate (153), has been shown to readily convert secondary alcohols into ketones under mild conditions, and in contrast to traditional permanganate reactivity, the reagent does not react with double bonds (154). 

The acid chloride of i i7-nitromethane, CH2=N(C1)0 (mp —43°C, bp 2—3°C), is formed by fusion of nitromethane and picrylpyridinium chloride (36). It is hydroly2ed to nitro some thane, reduces potassium permanganate strongly, and exhibits no reactions characteristic of hydroxamic acids. 

The common treatment methods are acidification, neutralization, and incineration. When oxahc acid is heated slightly in sulfuric acid, it is converted to carbon monoxide, carbon dioxide, and water. Reaction with acid potassium permanganate converts it to carbon dioxide. Neutralization with alkahes, such as caustic soda, yields soluble oxalates. Neutralization with lime gives practically insoluble calcium oxalate, which can be safely disposed of, for instance, by incineration. 

Silver Permanganate. Silver permanganate [7783-98-4] AgMnO, is a violet soHd formed when a potassium permanganate solution is added to a silver nitrate solution. It decomposes upon heating, exposure to light, or by reaction with alcohol. 

---