Gibbs energies, enthalpies and entropies of transfer of cations from acetonitrile and N,N-dimethylformamide into water

Abstract

Gibbs energies of transfer from acetonitrile and N,N-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/Mⁿ⁺(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 Mⁿ⁺/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 °C employing the assumption of a negligible thermal diffusion potential. Enthalpies of transfer were obtained from the Gibbs energies and the entropies of transfer.