MOLECULAR-DYNAMICS STUDIES ON THE STRUCTURE OF METHANOL-WATER SOLUTIONS OF NACL

Molecular dynamics simulations of NaCl solutions in water and in two methanol-water mixtures with methanol concentrations of 10 and 90 mol% at room temperature have been performed. Three-site flexible models of water and of methanol have been applied. The structural properties of the systems have been discussed on the basis of radial and angular distribution functions, the orientation of the solvent molecules and their geometrical arrangement in the solvation shells of ions. A preferential solvation of ions has been found. In the methanol-deficit mixture cations and anions are preferentially solvated by methanol molecules. In the methanol-rich system no preferential solvation of cations has been found, but the anions are solvated only by the methanol molecules.