Continuous countercurrent extraction process for removing water- soluble impurities from water immiscible polymer solutions

摘要

There is disclosed a continuous countercurrent extraction process for removing tertiary amine hydrochloride impurities which are soluble in water from a water immiscible polymer solution of a halogenated aromatic polyester which has a viscosity of at least about 10 poise and a density greater than about 1.0 gm/cc. This process comprises (a) introducing the polymer solution at the top of an extraction column and introducing water at the bottom of the column to form a two phase mixture, and (b) mechanically agitating the mixture in a particularly defined manner in order to extract the water-soluble impurities from the polymer solution and economically recover the tertiary amine hydrochloride.