Potassium superoxide oxidation

Potassium superoxide is produced commercially by spraying molten potassium iato an air stream, which may be enriched with oxygen. Excess air is used to dissipate the heat of reaction and to maintain the temperature at ca 300°C. It can also be prepared ia a highly pure state by oxidizing potassium metal that is dissolved ia Hquid ammonia at —50° C. 

Potassium Superoxide. Potassium, mbidium, and cesium form superoxides, MO2, upon oxidation by oxygen or air. Sodium yields the peroxide, Na202 lithium yields the oxide, Li20, when oxidized under comparable conditions. Potassium superoxide [12030-88-5] KO2 liberates oxygen in contact with moisture and carbon dioxide (qv). This important property enables KO2 to serve as an oxygen source in self-contained breathing equipment. 

Solutions of potassium superoxide-crown ether in dimethyl sulphoxide have been shown to cause oxidation of the solvent to the sulphone75 such a reaction could possibly be used synthetically. In the presence of water the reaction probably proceeds as shown ... 

Unsymmetrical thiosulphinates and thiosulphonates are both oxidized by potassium superoxide in pyridine in the presence of 18-crown-6 ether to produce sulphinic and sulphonic acids and a disulphide, under mild conditions (equation 84)200,201. Sulphinic and sulphonic acids were produced from both the R and R substituents whilst the disulphide was derived only from the sulphenyl side of the reactant. Thus, the reaction mixture contained five products, making the reaction not synthetically useful. Pyrolysis of thiosulphinates also produces mixtures of products, one being the thiosulphonate again this is not a synthetically useful reaction202. 

In the presence of air, there is very slow oxidation, which forms a layer of potassium superoxide as follows ... 

It violently reacts with strong oxidants such as ammonium perchlorate (ignition in contact with copper pip ), alkaline chlorates (detonation by heating, impact or friction powdered copper), ammonium nitrate (detonation molten ammonium nitrate and powdered copper) and potassium superoxide (copper glows). 

A zinc/potassium chlorate mixture is explosive on impact or friction. With potassium superoxide the metal glows. The same thing happens when a mixture of zinc and titanium oxide is heated or when nitric acid vapour is in contact with melted zinc ( 400°C). 

Arsenic is violently oxidised by strong oxidants. This applies to potassium superoxide (incandescence of the element), dichlorine oxide (the released heat causes the chlorinated derivative to detonate), chromium (III) oxide Oncande-scence), potassium or silver nitrates (ignition), potassium permanganate or sodium peroxide (detonations). 

Dining the preparation by solid phase interaction of tetramethylammonium hydroxide and potassium superoxide [1] by tumbling for several days in a rotary evaporator flask, a violent explosion occurred [2], This may have been caused by ingress of grease or other organic material leading to contact with potassium superoxide, a powerful oxidant. 

Potassium superoxide must not be added to neat oxidation substrates, or ignition may occur, and weighing it out on filter paper is also hazardous. 

Impact sensitivities of mixtures of red phosphorus with various oxidants were determined in a direct drop-ball method, which indicated higher sensitivities than those determined with an indirect striker mechanism. Mixtures with silver chlorate were most sensitive, those with bromates, chlorates and chlorites were extremely sensitive, and mixtures with sodium peroxide and potassium superoxide were more sensitive than those with barium, calcium, magnesium, strontium or zinc peroxides. Mixtures with perchlorates or iodates had sensitivities comparable to those of unmixed explosives, such as lead azide, 3,5-dinitrobenzenediazonium-2-oxide etc. 

Xanthine oxidase, a widely used source of superoxide, has been frequently applied for the study of the effects of superoxide on DNA oxidation. Rozenberg-Arska et al. [30] have shown that xanthine oxidase plus excess iron induced chromosomal and plasmid DNA injury, which was supposedly mediated by hydroxyl radicals. Ito et al. [31] compared the inactivation of Bacillus subtilis transforming DNA by potassium superoxide and the xanthine xanthine oxidase system. It was found that xanthine oxidase but not K02 was a source of free radical mediated DNA inactivation apparently due to the conversion of superoxide to hydroxyl radicals in the presence of iron ions. Deno and Fridovich [32] also supposed that the single strand scission formation after exposure of DNA plasmid to xanthine oxidase was mediated by hydroxyl radical formation. Oxygen radicals produced by xanthine oxidase induced DNA strand breakage in promotable and nonpromotable JB6 mouse epidermal cells [33]. 

Nitrites, inorganic Nitrogen oxides (NOx) Oxygen Peracetic acid Perchloric acid solutions Potassium bromate Potassium chlorate Potassium dichloro-s-triazinetrione (potassium dichloroisocyanurate) Potassium dichromate Potassium percarbonate Potassium perchlorate Potassium permanganate Potassium peroxide Potassium persulfate Potassium superoxide n-Propyl nitrate... 

Reactions of potassium superoxide solubilized in apolar solvents with crown ethers (see Oxidation reactions, p. 356) are also frequently accompanied by elimination reactions. Thus, in DMSO solution, secondary alkyl bromides only yield olefins when treated with the K02 complex of dicyclohexyl-18-crown-6 (Johnson et al., 1978). Scully and Davis (1978) have studied the elimination of HC1 from N-chloramines with 18-crown-6-solubilized K02, KOH, and KOAc in ether solution (27). High yields of aldimines were obtained with K02,... 

Interaction of T with potassium superoxide in acetonitrile generates a sulfinyl oxide (32), which then breaks down to give thianthrene, its 5-oxide, and oxygen in equal amounts. In experiments with added diaryl-... 

Potassium reacts with oxygen or air forming three oxides potassium monoxide, KaO potassium peroxide, KaOa and potassium superoxide, KOa. The nature of the product depends on oxygen supply. In limited supply of oxygen potassium monoxide is formed, while in excess oxygen, superoxide is... 

Also, potassium superoxide (KO2) decomposes DMD in acetone solution to release singlet oxygen, as has been detected by the characteristic infrared chemiluminescence . Furthermore, a catalytic amount of n-Bu4NI decomposes TFD into oxygen gas and triflu-oroacetone in high yield . Analogous to the Caroate decomposition by ketones, also the catalytic decomposition of peroxynitrite by ketones, e.g. methyl pyruvate, is rationahzed in terms of peroxynitrite oxidation by in-situ-generated dioxirane. ... 

The stoichiometry of the oxidation appears to require the formation of potassium superoxide as one of the oxidation products, particularly at long reaction periods and high base concentrations. An oxidation of 3.00 mmoles of benzhydrol (0.12M) in the presence of 9.9 mmoles of potassium terf-butoxide (0.37M) in DMSO (80% )-ter -butyl alcohol (20%) absorbed 4.95 mmoles of oxygen in 27.7 minutes at 25°C. and yielded 2.2 mmoles of the benzophenone-DMSO adduct and 0.8 mmole of benzophenone. A precipitate formed (0.307 gram) which analyzed (23) as 103% (4.25 mmoles) potassium superoxide (K02). 

The data apparently require a free radical chain mechanism for the oxidation of benzhydrol. Potassium superoxide filtered from a completed oxidation completely removed the induction period for a fresh oxidation. Thus, potassium superoxide must either serve as an initiation of oxidation... 

The effect of the concentration of base requires that the formation of superoxide from peroxide is more rapid and occurs to a greater extent at the higher base concentrations. This conclusion is difficult to test, because both potassium peroxide and potassium superoxide are insoluble in the oxidation solvent and potassium superoxide precipitates from solution with as much as 35% by weight of potassium terf-butoxide or potassium hydroxide (which can be removed by extraction with tert-butyl... 

The major oxidation product isolated was anthracene, perhaps formed in part from the hydroperoxide (I). However, significant amounts of potassium superoxide accompanied the anthracene. This result suggests that the major source of anthracene involved the oxidation of the dianion. In pure DMSO in the presence of excess potassium tert-butoxide, a trace of oxygen converts 9,10-dihydroanthracene, 9,10-dihy-drophenanthrene, or acenaphthene to the hydrocarbon radical anions. These products are apparently formed in the oxidation of the hydrocarbon dianions. 

Oxidation of Potassium Peroxide. Determination of Potassium Superoxide. Potassium peroxide was prepared by the addition of a tert-butyl alcohol solution of 90% hydrogen peroxide to potassium tert-butoxide in DMSO or tert-butyl alcohol. Oxygen absorption was followed in the standard manner (20). Analysis of solid precipitates for potassium superoxide followed exactly the method of Seyb and Kleinberg (23). Potassium superoxide formed in the oxidation of benzhydrol was determined in a 15-ml. aliquot of the oxidation solution. To this aliquot 10 ml. of diethyl phthlate was added to prevent freezing of the solution. The mixture was cooled to 0°C., and 10 ml. of acetic acid-diethyl phthlate (4 to 1) added over a period of 30 minutes with stirring. The volume of the evolved oxygen was measured. 

POTASSIUM PEROXIDE Potassium superoxide Oxidizing Material, Solid, 1 3 0 2 W... 

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