GB805860A - Improvements in or relating to the preparation of sulfur hexafluoride - Google Patents

Abstract

Sulphur hexafluoride, together with biproduct chloride, is prepared by interacting sulphur, chlorine and an inorganic binary fluoride of any element of Groups I-V and VIa of the Periodic Table at a temperature of at least 400 DEG C., e.g. 400-1000 DEG C., at atmospheric or superatmospheric pressure, preferably with shaking or stirring and in the absence of water. The reaction time may be 1-24 hours, usually 2-8 hours. The reaction is generally carried out in an autoclave of, for example, nickel iron and molybdenum, the autoclave being cooled at the end of the reaction and sulphur hexafluoride removed therefrom as a gas. The sulphur hexafluoride may be purified by an alkaline scrubbing followed by distillation. Fluorides specified are those of hydrogen, lithium, sodium, potassium, rubidium, cesium, copper, silver, gold, beryllium, magnesium, calcium, strontium, barium, zinc, cadmium, mercury, scandium, boron, aluminium, gallium, thallium, titanium, zirconium, silicon, germanium, tin, lead, vanadium, nitrogen, phosphorus, arsenic, antimony, bismuth, chromium and tungsten. Phosphorus and arsenic may be tri- or penta-valent, and chromium tetra- or hexa-valent. A sulphide of iron or copper, e.g. copper disulphide, may be used as a source of sulphur, and sulphur monochloride as a source both of sulphur and chlorine. 1-50 per cent of a catalyst, e.g. a perfluoro saturated monocarboxylic acid, PCl3, PCl5, SbCl5, CrCl2, CrCl3, FeF2, FeF3, FeCl2 and FeCl3, may be present. Specification 758,477, [Group IV (b)], is referred to.