Potassium permanganate, reaction with hydrochloric acid

A. 2-Methyl-2-nitropro]f)ane. To a well-stirred suspension of 650 g. (4.11 moles) of potassium permanganate in 3 1. of water, contained in a 5-1. three-necked flask fitted with a reflux condenser, a mechanical stirrer, a thermometer, and a 250-ml. dropping funnel, is added dropwise and with stirring over a 10-minute period, 100 g. (1.37 moles) of i-butylamine (Note 1). When the addition is complete, the reaction mixture is heated to 55° over a period of approximately 2 hours, and then the reaction mixture is maintained at 55° with continuous stirring for 3 hours. The dropping funnel and reflux condenser are replaced by a stopper and a still head fitted for steam distillation and the product is steam distilled from the reaction mixture (Note 2). The liquid product is separated from the denser water layer and then diluted with 250 ml. of ether and washed successively with two 50-ml. portions of aqueous 2M hydrochloric acid and with 50 ml. of water. After the ethereal solution has been dried over anhydrous magnesium sulfate, the solution is fractionally distilled at atmospheric pressure to remove the ether. The residual crude product (Note 3) amounts to 106-128 g. and is sufficiently pure for use in the next step. In a typical run, distillation of 124 g. of the crude product afforded 110 g. (78%) of the pure 2-methyl-2-nitrobutane as a colorless liquid, b.p. 127-128°, d 1.3992. The material slowly solidifies on standing to a waxy solid, m.p. 25-26° (Note 4). 

Acetyl-n-valeric acid has been prepared by the oxidation of 1-methylcyclohexene with potassium permanganate 5 by the oxidation of 2-methylcyclohexanone with chromic oxide and sulfuric acid 6 by the reaction of methylzinc iodide on the ethyl ester of adipic acid chloride and saponification of the ethyl ester of 5-acetyl-w-valeric acid so obtained 7 by the saponification of the ethyl ester of diacetylvaleric acid 2 and through the hydrolysis of ethyl a-acetyl-6-cyanovalerate with boiling 20% hydrochloric acid.3... 

The syringyl nucleus (4) in hardwood lignin is converted to the methoxycatechol structure (5) by treatment with potassium permanganate and hydrochloric acid and thence to a methoxy-o-quinone (6) following reaction with ammonium hydroxide. 

Synthesis and Reactivity Chlorine was first prepared by the Swedish chemist K.W. Scheele in 1774 using the reaction of manganese dioxide with hydrochloric acid. Erroneously, he thought that it was a compound of oxygen, and ultimately it was named and identified as an element by Sir Humphry Davy in 1810. The reaction of hydrochloric acid with potassium permanganate provides a second convenient route to small quantities of chlorine. 

Ferrous salts can be determined with potassium permanganate in sulfuric acid medium (see standardization. Sect. 20.1.1.2). The reaction may also be achieved in hydrochloric acid medium after the addition of a manganous sulfate (dissolved in... 

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... 

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. 

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