Process for the purification of phosphorus pentasulphide by distillation under vacuum
AssigneeSaffa S.p.A.
InventorPietro Molla
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Abstract
Process for the purification of phosphorus pentasulphide by means of distillation under vacuum at a residual pressure of about 6 mmHg and carried out according to a "thermal profile" comprising, immediately before and immediately after the liquid-vapor-liquid double passage of state, two stationary stages wherein said pentasulphide is maintained in the liquid state at a temperature very close to the boiling temperature of the pentasulphide itself.
Claims3
Process for the purification of phosphorous pentasulfide by means of distillation in which the phosphorous pentasulfide is liquified by heating at a temperature below its boiling point temperature, the liquified phosphorous pentasulfide is evaporated under reduced pressure at a temperature between 365.degree. and 380.degree. C., and the vapors of phosphorous pentasulfide are condensed by cooling, characterized in that the liquification, evaporation and condensation of the phosphorous pentasulfide are carried out at a residual pressure of about 6 mmHg, and the phosphorous pentasulfide both prior to and after the evaporation is heated and cooled respectively at a temperature between 315.degree. and 350.degree. C.
Dependencies are inferred from the claim text.