Abstract: A method for separating difluoromethane from a mixture of difluoromethane and at least one impurity, the method involving extractively distilling the mixture using dichloromethane as an extractive agent to recover a product stream of purified difluoromethane having a concentration of impurity lower than that of the mixture.

Abstract: A method for separating difluoromethane from a mixture of said difluoromethane and at least one impurity, said method comprising extractively distilling said mixture using dichloromethane as the extractive agent to recover a product stream of purified difluoromethane having a concentration of said impurity lower than that of said mixture.

Abstract: The invention generally relates to a process for the purification of a component of a binary azeotrope in which the composition of the azeotrope changes by about 10 mole percent with pressure comprising:(a) subjecting a binary azeotrope to a distillation step in which most of one of the binary components is removed as distillate (distillate 1) with the bottoms (bottoms 1) enriched in the other component;(b) subjecting distillate 1 to at least one additional distillation step conducted at a different pressure in which most of the component recovered as bottoms 1 is removed as distillate 2 with the bottoms 2 enriched in the component enriched in distillate 1;(c) optionally repeating step (b) as many times as desired; and(d) recovering the desired purified component.The invention is particularly useful in the purification of pentafluoroethane in a pentafluoroethane/chloropentafluoroethane azeotrope.