An empirical equation for the dielectric constant in aqueous and nonaqueous electrolyte mixtures

• New model with one parameter per ion/solvent computes dielectric constants.
• Dielectric constant is evaluated for salt solutions in water, methanol, or ethanol.
• New model is used for 9 two-solvent solutions of water, alkanols, or acetone.
• Dielectric constant is predicted in water/methanol/NaCl mixtures.
• General parameters are presented for mixtures with unavailable experimental data.

This work develops an empirical model to evaluate the dielectric constant of single or multi-solvents containing multiple ions, using only one adjustable parameter per ion. Correlations are performed for 35 salts in water, 9 in methanol, and 3 in ethanol. The dielectric constant of 9 two-solvent solutions (containing water, methanol, ethanol, 1-propanol, 2-propanol, or acetone) is predicted. In addition, predictions of the dielectric constant of a mixture containing water, methanol, and NaCl are presented. Besides the specific parameter for each ion, a general parameter for cations and another for anions, specific to the each solvent, are obtained. They are recommended for calculating the dielectric constant in solutions whose experimental data are unavailable in the literature.