Potassium compounds superoxide

The relevant properties of peroxide and superoxide salts are given in Table 4 (see Peroxides and peroxide compounds, inorganic). Potassium peroxide is difficult to prepare and lithium superoxide is very unstable. The ozonides, MO3, of the alkah metals contain a very high percentage of oxygen, but are only stable below room temperature (see Ozone). 

The carbon dioxide generated by the personnel in the artificial atmosphere of submarines and spacecraft must be removed from the air and the oxygen recovered. Submarine design teams have investigated the use of potassium superoxide, K02, as an air purifier because this compound reacts with carbon dioxide and releases oxygen (Fig. 4.16) ... 

The principal product of the reaction of the alkali metals with oxygen varies systematically down the group (Fig. 14.15). Ionic compounds formed from cations and anions of similar radius are commonly found to he more stable than those formed from ions with markedly different radii. Such is the case here. Lithium forms mainly the oxide, Li20. Sodium, which has a larger cation, forms predominantly the very pale yellow sodium peroxide, Na202. Potassium, with an even bigger cation, forms mainly the superoxide, K02, which contains the superoxide ion, O,. ... 

Underneath this layer of superoxide a layer of oxide KgO is formed. The interaction between potassium and its superoxide is violent and causes the metal to combust the intermediate layer acts as a protection. Contact between both compounds happens when the metal is cut. This slow oxidation is avoided by keeping potassium under anhydrous xylene. It is possible that many dangerous reactions may be in fact due to the exceptional reactivity of the superoxide. 

Potassium metal prepared by the old process of distilling an intimate mixture of the carbonate and carbon contained some carbonylpotassium (actually potassium benzenehexoxide), and several explosions with old samples of potassium may have involved this compound (or, perhaps more likely, potassium superoxide). 

Metals react with nonmetals. These reactions are oxidation-reduction reactions. (See Chapters 4 and 18). Oxidation of the metal occurs in conjunction with reduction of the nonmetal. In most cases, only simple compounds will form. For example, oxygen, 02, reacts with nearly all metals to form oxides (compounds containing O2-). Exceptions are the reaction with sodium where sodium peroxide, Na202, forms and the reaction with potassium, rubidium, and cesium where the superoxides, K02, Rb02, and Cs02 form. 

Mine Safety Appliances Co. (MSA) manufactures potassium superoxide in the United States for use in self-contained breathing equipment. There are several published uses for potassium superoxide in organic chemistry, e.g., for oxidizing aromatic compounds and for initiating anionic polymerization. 

The chemical bond between the superoxide ion, OJ, and the metal ion is ionic in nature. Melting points of potassium, rubidium and cesium superoxide have been determined, and in keeping with the ionic nature of the compounds, the melting temperatures arc high, in the order of 400°C. 

Potassium superoxide, K02, is a particularly valuable compound because of its use in spacecraft and in self-contained breathing devices to remove moisture and C02 from exhaled air, generating oxygen in the process ... 

In peroxides, the oxidation number of oxygen IS -1, and in superoxides, it is -5. The only common superoxides are those of hydrogen and the alkali metals from potassium through francium. Peroxides occur with hydrogen, sodium, barium, and chromium, and in these compounds, each of these elements exists in its highest oxidation state. 

Diphenylhydrazine is oxidized to diphenylnitrosamine (50%) by potassium superoxide. The same reagent also oxidizes 1-methyl-1-phenylhydrazine, but here the nitrosamine is a minor product the major reaction is deamination. A better meAod of oxidative deamination of some 1,1-disubstituted hydrazines and hydrazinium salts is reaction with nitrous acid. Thus, several hydrazinium salts MezRN NHi X were deaminated to the tertiary amine by treatment with nitrous acid. The method has also been used to deaminate IV-aminoheterocyclic compounds for example, some 1,2,3-triazoles are conveniently prepared by deamination of the corresponding 1-aminotriazoles with nitrous acid. °... 

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