SOLUBILITY OF POTASSIUM SULFATE IN AQUEOUS SOLUTIONS OF POLYETHYLENE GLYCOL

A.P. Krasnopyorova, G.D. Yuhno, L.T. Lebedeva

Kharkov National University of V.N. Karazin, Svobody square 4, Kharkov, Ukraine
e-mail:alla.p.krasnopyorova@univer.kharkov.ua

Researches of solubility of salts in the mixed solvents is very important for development of salting-out theory, for example salting-out and developments of practical recommendations for lead through of processes of selective extraction and rectification. When choosing the extraction system it is important to know the degree of transition of substance from one phase in other, which can be estimated from data of solubility.
Presented work is a continuation of systematic researches of solubility of salts in aqueous solutions of PEG.
Solubility of potassium sulfate in aqueous solutions of polyethylene glycol - 3000 (PEG-3000) and polyethylene glycol - 4000 (PEG-4000) studied at 293.15 K. For thermo stating an air thermostat has been used. Equilibrium in the systems was set during 3 days.

Fig. Dependence of solubility K2SO4 from composition of solvent: 1-water-PEG-3000; 2 –water-PEG-4000

The concentration of potassium sulfate in equilibrium saturated solution was determined by flaming emission spectrometry and roentgen fluorescent analysis. The bottom phases were analyzed by RFA method on the diffract meter DRON-3. The survey of roentgenogram of the ground phases was performed under the layer of equilibrium solution in order to avoid decomposition of crystal solvates. Comparing received roentgenograms and roentgenograms of clean potassium sulfate reached a conclusion, that the ground phase in all of examples of the system is a potassium sulfate.
Researches of solubility of potassium sulfate in the mixed solvents show, that dependence of solubility on composition of solvent carry a difficult character. Solubility of potassium sulfate in aqueous solutions of polyethylene glycol depends on the row of factors where determining influence is rendered by intermolecular interaction in the mixed water – polyethylene glycol solvent.