PROCESS FOR CLEANING 1,1,1,2-TETRAFLUOROETHANE FROM UNSATURATED HALOGENATED IMPURITIES Russian patent published in 1995 - IPC

FIELD: in the production of flurochlorosubstituted hydrocarbons. SUBSTANCE: R-134a is cleaned from unsaturated halogenated impurities (R-1113, R-1123, R-1243 and R-1225) by passing contaminated R-134a with the total amount of the impurities mentioned above of not greater than 10,000 ppm through a layer of carbon at 253-323 K at a pressure not greater than the pressure of saturated R-124a vapors at the given temperature. The specific flow rate of the gas being cleaned is not greater than 0,35 kg/(mm²·s). The total amount of impurities after the cleaning operation does not exceed 10 ppm. To make the process more efficient, before absorption begins R-134a which contains no impurities of unsaturated halogen hydrocarbons is passed through a layer or adsorbent. The absorbent is carbon of sulfur-potassium activation with an ultimate volume of sorption space of 0,50-0,80 cm³/g. The adsorbent is regenerated at 473 to 523 K and at a pressure of 2·10^-4 to 0.15 MPa. In this case, the absorbed products become completely desorbed. The number of sorption cycles is determined by mechanical strength of carbons. EFFECT: more efficient cleaning process. 2 tbl