Transfer energetics of some ions based on TATB assumption in some quasi-isodielectric ethylene carbonate + water mixtures

Abstract

Single-ion transfer free energies, △G<img src='http://www.niscair.res.in/jinfo/equation30.gif' border=0> (i), and entropies, △S<img src='http://www.niscair.res.in/jinfo/equation30.gif' border=0> (i), of some electrolytes from water to quasi-isodielectric aqueous mixtures of 10, 30. 50 and 70 weight per cent ethylene carbonate (EC) have been determined at 35°C, using the widely used tetraphenylarsonium tetraphenylborate [Pb₄AsPh₄B(TATB)] reference electrolyte (RE) assumption, from solubility and emf measurements at five equidistant temperatures ranging from 25° to 45° Analysis of △G<img src='http://www.niscair.res.in/jinfo/equation30.gif' border=0> (i) values of the ions as well as their chemical effects △G<img src='http://www.niscair.res.in/jinfo/equation30.gif' border=0>,_ch(i),as obtained after correcting for their cavity effect, estimated by the scaled particle theory (SPT) and the Born as well as ion-dipole type electrostatic effects, estimated by use of simple Born and Kim formulations respectively, reveals that cationophilicity, anionophobicity and/or predominant dispersion interactions of the solvent mixtures are guiding the solvation behaviour of the ions. But the analysis of the corresponding T△S<img src='http://www.niscair.res.in/jinfo/equation30.gif' border=0>,_ch(i),values in the light of Kundu <em>et al’s </em> four-step transfer process reveals that complex structural changes are guiding the entropic behaviour of these ions in these quasi-isodielectric EC-water mixtures.