Single-ion transfer Gibbs energies in binary mixtures of isodielectric protic ethylene glycol and dipolar aprotic N,N-dimethyl formamide

Abstract

Single-ion transfer Gibbs energies, Δ<i>G</i>^o_t(i) of some electrolytes like tetrapheny larsonium picrate, potassium tetraphenylborate, potassium picrate and potassium chloride from protic ethylene glycol to isodielectric mixtures of

ethylene glycol and dipolar aprotic DMF with 20,40 and 60 wt.% DMF compositions have been determined at 25°C by measuring solubility of the salts at 25°C and using the widely accepted TATB reference electrolyte assumption. The chemical effects of the transfer Gibbs energies of the ions, Δ<i>G</i>^o_t,_ch(i) have been obtained after correcting for the cavity effect, Δ<i>G</i>^o_t,_cav(i), estimated by the scaled particle theory, the ion-dipole interaction effects, Δ<i>G</i>^o_t,_(i-d)(i) , estimated by use of Kim formulations and ignoring Born -type electrostatic effect, Δ<i>G</i>^o_t,_Born(i) , since the solvent mixtures are isodielectric. The observed results on careful analysis reveal that increased cationophilicity, an ionophobiciity, dispersion interaction and aproticity of the solvent mixtures are guiding the solvation behaviour of the ions. The study also recognizes ‘solvophobic

solvation’ for the large organic ions in ethylene glycol and its mixtures similar to hydrophobic hydration &nbsp;in water and its mixtures with other cosolvents.