METHOD OF PURIFYING PHOSPHORUS TRICHLORIDE Russian patent published in 2012 - IPC C01B25/10 

FIELD: chemistry.

SUBSTANCE: invention can be used to produce semiconductor compounds. Phosphorus trichloride undergoes gas-phase thermal treatment at temperature 350-450°C on inorganic oxide sorbents modified with rare-earth elements. The obtained vapour is condensed and the condensate undergoes rectification purification. Further, the liquid rectificate undergoes microfiltration at temperature -85 - (-90°C) on polymer microfilters with pore size in the range of 0.2-0.5 mcm. The filtrate is evaporated in bubble free boiling conditions and the vapour phase is purified through microfiltration at temperature 75 - 95°C. The inorganic oxide sorbents used are sorbents based on aluminium oxide and silicon oxide, modified with rare-earth elements.

EFFECT: method provides fine purification of phosphorus trichloride and enables to obtain a product containing impurities of several elements, eg, aluminium, gallium, iron, selenium and sulphur, each in amount of 1×10^-7 - 10^-8 wt %.

3 cl, 3 ex