RESEARCH OF SOME AQUEOUS TWO-PHASE SYSTEMS BASED ON POLYETHYLENE GLYCOL-6000 AND CERTAIN ORGANIC ACID SALTS
The phase diagrams of aqueous two-phase systems of PEG-6000-organic salt, where are taken as salt sodium salts of citric and succinic acids, as well as optically active D-(+)-sodium tartrate and D-(+)-potassium sodium tartrate have been studied. By desalting capacity of these salts are in sequence: sodium succinate < sodium tartrate ≤ potassium sodium tartrate < sodium citrate. By the methods of refractometry and volumetry in a relatively wide concentration range of aqueous solutions of said salts have been studied. Their partial molar volumes in aqueous solutions have been determined. The equations of depending of the partial molar volumes of salt on their concentration in the solution have been obtained. It was shown that on the size of partial molar volumes these salts are placed in a row: sodium succinate < sodium tartrate ≤ sodium potassium tartrate < sodium citrate, which is in agreement with their desalting ability. The effect of urea, glucose and sucrose on the phase diagrams of aqueous two-phase system of PEG 6000-sodium citrate and PEG 6000-sodium succinate have been studied.