Solute-Solvent Interactions in Ion Pair Extraction of Tetraalkylammonium Iodides. II. The Effect of Hydration of Iodide in Organic Solvents on the Extraction Constant

Solubilities of tetraalkylammonium iodides Et4NI, Pr4NI, and Bu4NI in nitrobenzene, in water, and in their mutually saturated solvents, and of Pr4NI in 1,1-dichloroethane and in its water saturated solvent were measured at 25 °C. Conductances of Et4NI, Pr4NI, and Bu4NI in nitrobenzene and Bu4NI in 1,1-dichloroethane, 1,2-dichloroethane, and dichloromethane have also been measured at 25 °C. A small amount of water in organic solvents increases the solubilities of the salts roughly twice those in pure solvents and decreases the association constants around 15% while a small amount of organic solvent in water gives a slight effect. Effects of mutual saturation of water and organic solvent on extraction equilibria of R4NI were discussed in terms of the selective hydration of the iodide.