Conductometric study of calcium(II), strontium(II), and barium(II) perchlorates in methanol-ethylene glycol mixtures

The ion-association constants, K1A, of an ion pair, M 2+ClO4- (M=Ca, Sr, Ba), have been determined by conductometric measurements in methanol-ethylene glycol mixtures of 0, 20, 40, 60, 80, and 100 wt% of ethylene glycol at 5, 15, 25, 35, and 45°C. The conductometric data were treated by an improved Fuoss and Edelson method. The thermodynamic functions of ΔH1A and ΔS1A have also been determined at 25 °C from the temperature dependence of K 1A. In 60-80 wt% of ethylene glycol the K1A values of these metal Perchlorates are similar to each other, since the characteristics of individual metal ions are probably depressed by the strong solvations of those cations. The results are discussed while considering the cation solvation and structure of a bulk solvent. © 1990 The Chemical Society of Japan.