Potassium permanganate reagent

Bromocresol Green — Bromophenol Blue — Potassium Permanganate Reagent... 

Bromocresol Green—Bromophenol Blue—Potassium Permanganate Reagent 229... 

Assay The initial sample is dissolved in a mixture of hot sulfuric acid and ammonium sulfate. After the dissolution is complete, the mixture is allowed to cool, and diluted with water. The suspension is then filtered, and neutralized with ammonium hydroxide. This filtrate is reduced in a Jones reductor (making use of a zinc amalgam), and then titrated with 0.1 N potassium permanganate volumetric reagent. Under these conditions, each mL of 0.1 N potassium permanganate reagent is equivalent to 7.988 mg of TiOj. 

Potassium permanganate reagent Dissolve 3 g of potassium permanganate in a mixture of 15 ml of concentrated phosphoric acid and 70 ml of water and dilute with water to 100 ml. 

Dilute 0 5 ml of the sample to 5 ml with water, add 2 0 ml of the potassium permanganate reagent, allow to stand for ten minutes and add 2 0 ml of the oxalic acid reagent. To the colourless solution add 5 ml of Schiff s reagent, allow to stand at a temperature between 15° and 30° and examine after thirty minutes. 

The analytical reagent grade is suitable for most purposes. The commercial substance may be purifled by shaking for 3 hours with three portions of potassium permanganate solution (5 g. per litre), twice for 6 hours with mercury, and Anally with a solution of mercuric sulphate (2-5 g. per litre). It is then dried over anhydrous calcium chloride, and fractionated from a water bath at 55-65°. The pure compound boils at 46-5°/760 mm. 

Potassium permanganate test. Dissolve 0 -2 g. or 0 -2 ml. of the substance in 2 ml. of water or in 2 ml. of acetone (which gives a negative test with the reagent), and add 2 per cent, potassium permanganate solution dropwise. The test is negative if no more than 3 drops of the reagent are decolourised. 

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). 

Both technical- and reagent-grade phosphoms pentoxide is typically >99% P O q. Phosphoms pentoxide sublimes near 360°C at atmospheric pressure. Lower oxides, which may account for <0.3% (as P40 ) in technical-grade material, are present at <0.02% in reagent-grade phosphoms pentoxide. Lower oxides are detected by decolorization of a dilute potassium permanganate solution (Table 11). 

Separated polyols are detected by a variety of reagents, including ammoniacal silver nitrate (175), concentrated sulfuric acid, potassium permanganate (163), lead tetraacetate, and potassium teUuratocuprate (176). A mixture of sodium metaperiodate and potassium permanganate can be used to detect as htde as 5—8 ).tg of mannitol or erythritol (177). 

Chemical Treatment. Some organic compounds are attacked by chemical reagents such as potassium permanganate, sodium hydroxide, calcium hypochlorite, and o2one (29,30). 

Chlorate Analysis. Chlorate ion concentration is determined by reaction with a reducing agent. Ferrous sulfate is preferred for quaHty control (111), but other reagents, such as arsenious acid, stannous chloride, and potassium iodide, have also been used (112). When ferrous sulfate is used, a measured excess of the reagent is added to a strong hydrochloric acid solution of the chlorate for reduction, after which the excess ferrous sulfate is titrated with an oxidant, usually potassium permanganate or potassium dichromate. 

Oxidation. Oxidation is one of the main chemical methods to treat and decompose dyes in wastewater. The oxidation agents used ate chlorine, bleach, ozone, hydrogen peroxide, Fenton s reagent, and potassium permanganate. 

Since osmium tetroxide is expensive and toxic, alternate reagents were also explored. This has led to the use of potassium permanganate by two different groups. ... 

The immediate outcome of the Hantzsch synthesis is the dihydropyridine which requires a subsequent oxidation step to generate the pyridine core. Classically, this has been accomplished with nitric acid. Alternative reagents include oxygen, sodium nitrite, ferric nitrate/cupric nitrate, bromine/sodium acetate, chromium trioxide, sulfur, potassium permanganate, chloranil, DDQ, Pd/C and DBU. More recently, ceric ammonium nitrate (CAN) has been found to be an efficient reagent to carry out this transformation. When 100 was treated with 2 equivalents of CAN in aqueous acetone, the reaction to 101 was complete in 10 minutes at room temperature and in excellent yield. 

Heterocyclic compounds that have water bound covalently across a C=N bond behave as secondary alcohols. When subjected to very gentle oxidative conditions, they are converted into the corresponding 0x0 compounds. Potassium permanganate in 0. IN sodium hydroxide at room temperature has been used to oxidize 2- and 6-hydroxypteri-dine to 2,4- and 6,7-dihydroxypteridine, respectively. In contrast, 4-hydroxypteridine was not attacked by this reagent even at 100°. Hydrogen peroxide in acid solution was used to oxidize quinazoline quinazoline 3-oxide 1,3,5-, 1,3,7-, and 1,3,8-triazanaphthalene and pteridine (which hydrate across the 3,4-double bond in the... 

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