GIBBS ENERGIES, ENTHALPIES AND ENTROPIES OF TRANSFER OF CATIONS FROM ACETONITRILE AND N,N-DIMETHYLFORMAMIDE INTO WATER

Gibbs energies of transfer from acetonitrile and NN-dimethylformamide into water for the cations Li+, Na+, K+, Rb+, Cs+, Ag+, Tl+, Ba2+, Cu2+, Zn2+, Cd2+, and Pb2+ have been calculated from reversible polarographic half-wave potentials on the basis of the bis(biphenyl)chromium assumption. Gibbs energies of transfer for Ag+ and Hg2+ were obtained from the potentials of the respective M/M(n+) (0.01 mol dm-3) electrodes. Good agreement was found with Gibbs energies of transfer obtained from the tetraphenylarsonium tetraphenylborate assumption. Reaction entropies for the systems M(n+)/M(Hg) and entropies of transfer have been derived from measurements of the temperature coefficents of the polarographic half-wave potentials vs. Ag/Ag+ (0.01 mol dm-3) electrodes kept at 25-degrees-C employing the assumption of a negligible thermal diffusion potential. Enthalpies of transfer were obtained from the Gibbs energies and the entropies of transfer.