Solvation of Ions in Aqueous Solutions of Hydrophobic Solutes
Abstract The self-diffusion of Na+, Et4N+ and I- in mixtures of water with n-propanol at 25 °C and with lert-butanol at 30 °C was measured as function of salt concentration and solvent composition. The limiting self-diffusion coefficients of the ions were used to compute the ionic radii. The influence of the composition of the solvent on the solvation of the ions is discussed. In aqueous solutions of both alcohols the effective ionic radii are reduced. The strongest influence is found for the same solvent composition for which the highest concentration of the alcohol clusters has been reported. Hydra-tion of the clusters of n-propanol causes a vanishing of the second hydration shell of Na+ and the first one of Et4N+ and I-. In the case of terf-butanol even the first hydration shell of Na+ is partially reduced.