Solvation of halide ions and the iodine molecule in binary mixtures of water + oxydipropionitrile application to extraction

In water-rich mixtures, the addition of oxydipropionitrile (ODPN) does not alter the solvation of halide ions, they are preferentially solvated by water. In ODPN-rich media, the addition of water to the poor solvent increases the solvation of halide ions by forming hydrogen bonds with water molecules. The iodine molecule is solvated mainly by ODPN and addition of water to the solvent has little influence. The triiodide complex, a highly polarisable species behaves in the same way as the iodine molecule. On demixing, the halide ions are solvated in a similar way in the water-rich phase and very differently in the solvent-rich phase. Advantage is taken of this property to extract cationic complexes quantitatively from their aqueous solutions with ODPN.