THERMODYNAMICS OF HIGH-TEMPERATURE ELECTROLYTE-SOLUTIONS - VAPOR-LIQUID-EQUILIBRIUM

Two procedures have been employed to calculate from experimental data the value at infinite dilution of the distribution ratio of electrolyt e between the liquid and vapour phases in equilibrium, K(D)infinity. F or aqueous NaCl and KCl, K(D)infinity shows the expected asymptotic be haviour when the critical point of the solvent is approached. The ther modynamic evidence suggests that in the range 573 to 643 K the values of K(D)infinity are dominated by a single species. The results were co mpared to the predictions of cluster theory. Theory indicates that ion s in the vapour phase are strongly associated into neutral clusters, t he dominant species changing with temperature. In this first report of our work we discuss various alternatives to resolve this apparent dis crepancy.