Phase Equilibrium and Distribution Ratio of Sodium between Versatic Acid 10 and Aqueous Solution Containing Sodium

In order to study the phase equilibrium and the behavior of sodium between aqueous solution containing sodium and versatic acid 10 without diluent, the equilibrium of the H2O-NaNO3-VA10 system, the H2O-NaOH-NaNO3-VA10 system and the H2O-NaOH-VA10 system were investigated at 298 K.In the case of aqueous solution containing NaOH, the logarithmic distribution ratio, logDNa, increases approximately linearly with pH in the range of 5.5 to 6.8, then decreases through a maximum value and finally approaches DNa=1 at a pH value of nearly 8. On the other hand, sodium is hardly extracted by versatic acid 10 from aqueous solution without NaOH in the region of pH values below 4.The liquidus surface and tie lines between organic and aqueous phases were constructed on a composition tetrahedron of the H2O-NaOH-NaNO3-VA10 system. It is found that sodium is concentrated in the organic phase more than in the aqueous phase. It seems that the organic phase is equilibrated with the aqueous phase which liquidus surface extends towards the direction of two components of NaOH and NaNO3.