Dielectric properties of aqueous potassium chloride solutions as a function of temperature

The complex dielectric constant of aqueous potassium chloride solutions, including high-concentration (4 M) solutions, was studied from 283 to 313 K in the microwave range (the region in which water has a maximal dispersion). The static dielectric constant and relaxation time (epsilon(s) and tau) of KCl solutions were studied as functions of temperature and concentration. In high-concentration solutions, epsilon(s) approximate to 40, as opposed to water, which has epsilon(s) approximate to 80. The epsilon(s) of concentrated solutions is in fact independent of temperature. The nonexistence of the initial structure of bulk water in these solutions is responsible for this effect. The time and activation parameters of dielectric relaxation in solutions were calculated. They confirm that K+ and Cl- ions destroy the hydrogen-bond network of water; this effect almost vanishes at about 313 K.