Fluid Phase Equilibria, Vol.282, No.1, 51-57, 2009
Study on ion-solvent interactions of alkali metal salts in pure methanol and its binary mixtures with ethane-1,2-diol by a conductometric technique
Electrolytic conductivities of some sodium salts (Nal, NaSCN, CH3COONa) have been studied in 0, 25, 50 and 75 mass% ethane-1,2-diol + methyl alcohol mixtures at 293.15,298.15 and 303.15 K. The limiting molar conductivity (Lambda degrees), the association constant (K-A) and the distance of closest approach of ion (R) have been evaluated using the Fuoss conductance equation (1978). The association constant (K-A) decreases with temperature while it tends to decrease in the order: 0 mass% > 25 mass% > 50 mass% > 75 mass% ethane-1,2-diol + methyl alcohol mixtures. Thermodynamic parameters Delta H degrees, Delta G degrees and Delta S degrees along with the Walden products (Lambda degrees eta) are obtained and discussed. The results have been interpreted in terms of ion-solvent interactions and structural changes in the mixed solvents. (C) 2009 Published by Elsevier B.V.