Thermodynamics of Dissociation of Strontium, Barium and Nickel Caproates in Water

The critical micellar concentration (CMC) and thermodynamic parameters (heat Delta H-d, free energy Delta G(d), and entropy Delta S-d, of dissociation) of aqueous solutions of strontium, barium and nickel caproates were determined by conductivity measurements. A Kraus and Bray-type expression was used to evaluate molecular conductance at infinite dilution and theromdynamic parameters. The results confirm that CMC remains unaffected by temperature in the range of 25-55 degrees C, and show that the dissociation of soaps is an exothermic reaction and nonspontaneous.