Potassium permanganate-Copper

Several references have appeared on the use of solid-phase oxidants. Solid potassium permanganate-copper sulphate mixtures oxidize secondary alcohols to ketones in high yield, and pyridinium chromate or chromic acid on silica gel are described as convenient off-the-shelf reagents for oxidation of both primary and secondary alcohols. Anhydrous chromium trioxide-celite effects similar transformations only when ether is present as co-solvent. An excellent review, with over 400 references, on supported oxidants covers the use of silver carbonate-celite, chromium trioxide-pyridine-celite, ozone-silica, chromyl chloride-silica, chromium trioxide-graphite, manganese dioxide-carbon, and potassium permanganate-molecular sieve. 

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 electrolytic oxidation of quinoxaline at a copper anode gives pyrazine-2,3-dicarboxylic acid in excellent yield. A similar conversion may be effected with alkaline potassium permanganate, and a list of quinoxaline derivatives which can be oxidized with potassium... 

Some of the substances you work with in general chemistry can be identified at least tentatively by their color. Gaseous nitrogen dioxide has a brown color vapors of bromine and iodine are red and violet, respectively. A water solution of copper sulfate is blue, and a solution of potassium permanganate is purple (Figure 1.14). 

The standardisation of thiosulphate solutions may be effected with potassium iodate, potassium dichromate, copper and iodine as primary standards, or with potassium permanganate or cerium)IV) sulphate as secondary standards. Owing to the volatility of iodine and the difficulty of preparation of perfectly pure iodine, this method is not a suitable one for beginners. If, however, a standard solution of iodine (see Sections 10.112 and 10.113) is available, this maybe used for the standardisation of thiosulphate solutions. 

Phase-transfer catalysed oxidation of sulphoxides to sulphones using copper(II) permanganate or a mixture of potassium permanganate and copper(II) sulphate is also possible156. In this case hexane is used as the solvent for the organic phase and the reaction is carried out under reflux for 24 hours. Sulphones are prepared by this method in quantitative yields and the mechanism proposed is given in equation (51). 

Colour - A striking feature of transition-metal compounds is their colour. Whether it is the pale blue or pink hues of copper(ii) sulfate and cobalt(ii) chloride, or the intense purple of potassium permanganate, these colours tend to be associated most commonly with transition-metal compounds. It is rare for compounds of main group metals to be highly coloured. 

Methyldichlorosilane (CH3SiHCl2) combusts spontaneously in the presence of potassium permanganate, lead oxide and dioxide, copper (II) oxide and silver oxide, even when they are in an atmosphere of inert gas. 

The pure material is not ignited by impact, but it is in presence of potassium permanganate or lead(II),(IV) oxide [1], or by copper oxide or silver oxide, even under an inert gas [2],... 

In a review of the course and mechanism of the catalytic decomposition of ammonium perchlorate, the considerable effects of metal oxides in reducing the explosion temperature of the salt are described [1], Solymosi s previous work had shown reductions from 440° to about 270° by dichromium trioxide, to 260° by 10 mol% of cadmium oxide and to 200°C by 0.2% of zinc oxide. The effect of various concentrations of copper chromite , copper oxide, iron oxide and potassium permanganate on the catalysed combustion of the propellant salt was studied [2], Similar studies on the effects of compounds of 11 metals and potassium dichromate in particular, have been reported [3], Presence of calcium carbonate or calcium oxide has a stabilising effect on the salt, either alone or in admixture with polystyrene [4],... 

The effect of inorganic additives upon ignition delay in anilinium nitrate-red finning nitric acid systems was examined. The insoluble compounds copper(I) chloride, potassium permanganate, sodium pentacyanonitrosylferrate and vanadium(V) oxide were moderately effective promoters, while the soluble ammonium or sodium metavanadates were very effective, producing vigorous ignition. 

Bis(benzene)chromium dichromate, 3851 Calcium chromate, 3926 Copper chromate oxide, 4223 Dibismuth dichromium nonaoxide, 0232 Lead chromate, 4243 Lithium chromate, 4236 Magnesium permanganate, 4691 Potassium dichromate, 4248 Potassium permanganate, 4647 Sodium dichromate, 4250 Sodium molybdate, 4713 Sodium permanganate, 4703 Zinc permanganate, 4710... 

Oxidation of methylpyridines in 60-80 % sulphuric acid at a lead dioxide anode leads to the pyridinecarboxylic acid [213]. The sulphuric acid concentration is critical and little of the product is formed in dilute sulphuric acid [214]. In these reactions, electron loss from the n-system is driven by concerted cleavage of a carbon-hydrogen bond in the methyl substituent. This leaves a pyridylmethyl radical, which is then further oxidised to the acid, fhe procedure is run on a technical scale in a divided cell to give the pyridinecarboxylic acid in 80 % yields [215]. Oxida-tionof quinoline under the same conditions leads to pyridine-2,3-dicarboxylic acid [214, 216]. 3-HaIoquino ines afford the 5-halopyridine-2,3-dicarboxylic acid [217]. Quinoxaline is converted to pyrazine-2,3-dicarboxylic acid by oxidation at a copper anode in aqueous sodium hydroxide containing potassium permanganate [218]. 

Burns produced by phosphorus are very dangerous If white phosphorus gets on your skin, immediately remove it and wash the burnt spot with a 2% silver nitrate, copper sulphate, or potassium permanganate solution. After carrying out experiments with white or red phosphorus, immerse the laboratory ware for some time in a 10% copper sulphate solution, after which wash it in the usual way. 

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