Effect of bivalent cation inorganic salts on isobaric vapor-liquid equilibrium of methyl acetate-methanol system

The salt effect of four inorganic salts, namely; zinc nitrate, calcium nitrate, magnesium nitrate and magnesium chloride on the vapor liquid equilibria of the binary methyl acetate-methanol system was investigated using a modified Othmer still at 1atm. The salting out effect of methyl acetate was studied at different salt concentrations. For a salt concentration of 5wt%, it was found that zinc nitrate gives better salting out effect than calcium and magnesium nitrate. Magnesium chloride also shows a salting out effect, but could not eliminate the azeotrope completely, even at higher salt concentrations. It is observed that the bivalent cation salts (ZnNO<inf>3</inf>, CaNO<inf>3</inf>, MgNO<inf>3</inf> and MgCl<inf>2</inf>) had greater salting out effect than univalent cation salts (LiNO<inf>3</inf>,LiCl) reported earlier. Further, salting out coefficients were calculated using the scaled particle theory. The experimental vapor-liquid equilibrium data with the salts was compared with that calculated using the scaled particle theory, but only qualitative agreement was observed.