SELF-DIFFUSION IN WATER ALCOHOL SYSTEMS .3. 1-PROPANOL WATER SOLUTIONS OF NAI

Self-diffusion coefficients of water and of 1-propanol have been determined in the salt free mixtures and in NaI solutions at 25.0 +/- 0.01-degrees-C. Assuming perfect slipping boundary conditions, hydrodynamic radii of both components have been calculated. Their values have indicated that diffusing units of water and of 1-propanol are not the single molecules. In aqueous solutions, below 20 mol % of alcohol clusters has been found. In alcohol-rich mixtures, above 50 mol % PA, motions of water molecules are strongly correlated with those of alcohol ones, which indicates that a water molecule is able to coordinate up to four alcohol molecules. In NaI solutions because of a preferential hydration of sodium ions such a phenomenon does not occur.