OXIDATION OF SULFUR HEXAFLUORIDE,
AEROSPACE CORP EL SEGUNDO CALIF LAB OPERATIONS
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Although SF6 is extraordinarily inert toward oxygen, reaction can be initiated by the electrical explosion of extremely small masses of platinum into SF6 - O2 mixtures. It is shown that chemically trivial amounts of exploding metal can be effective initiators of the SF6 oxidation. Under our experimental conditions, the major reaction forms SOF4. Sulfuryl fluoride is a minor product, but thionyl fluoride is formed to a more significant extent. The data indicate that thionyl fluoride is formed by initial pyrolysis of SF6 to SF4, followed by rapid oxidation of the latter. The extreme slowness of the SF6 oxidation is demonstrated by the very small conversion of electrical to chemical energy and by the fact that the observed products are far from equilibrium, despite the initial attainment of temperatures above 5000K in a significant volume of the reactants. In contrast, endothermic oxidations of SF4 with either O2 or NO2 are very fast. Extremely efficient conversion of electrical to chemical energy is obtained when small metal masses are exploded in these gaseous mixtures. The predominant product is always SOF2, but minor amounts of SOF4, SO2F2, SO2, and SF6 form to different extents when reaction parameters are varied. SF5Cl oxidation reactions are also fast by comparison to SF6 oxidation, and the predominant product of SF5-Cl oxidation initiated by metal explosions is likewise SOF2.
- Inorganic Chemistry