Preferential solvation of some silver(I) salts in iso‐dielectric mixtures of methanol and N‐Methyl‐2‐pyrrolidinone at 30°

Abstract

The solvation behavior of various silver(I) salts, viz. silver (I) iodate, bromate and sulfate in iso‐dielectric solvent mixtures of methanol and N‐methyl‐2‐pyrrolidinone (NMP) has been investigated using Gibbs transfer energies and solvent transport number measurements. The Gibbs transfer energies of the salts were split into their individual ionic contributions using both negligible liquid junction potential method (nLJP) and the reference electrolyte method using tetraphenylarsonium tetraphenylborate (TATB). The results show a significant hetero‐selective solvation of all salts beyond XNMP = 0.5 with silver ion being selectively solvated by NMP and the anions by methanol.

Ion-Solvation Behavior of Some Copper(II) Salts in Isodielectric Solvent Mixtures of Methanol and N-Methyl-2-pyrrolidinone at 30 °C

“…For this purpose the ∆ t G°o f the reference electrolyte, tetraphenylarsonium tetraphenylborate is split equally between the cation (Ph 4 As + ) and anion (BPh 4 -) (eq 6) for reasons discussed previously (Kundu and Parker, 1980). The standard Gibbs transfer energy of copper(II) ion, ∆ t G°(Cu 2+ ) (on the basis of the TATB method) was calculated by utilizing the ∆ t G°of iodate ion determined earlier (Varadarajan et al, 1997) on the same method and combining it with ∆ t G°[Cu(IO 3 ) 2 ] according to the equation…”

“…The standard Gibbs transfer energy of copper(II) ion, ∆ t G°(Cu 2+ ) (on the basis of the TATB method) was calcu-lated by utilizing the ∆ t G°of iodate ion determined earlier (Varadarajan et al, 1997) on the same method and combining it with ∆ t G°[Cu(IO 3 ) 2 ] according to the equation The standard Gibbs transfer energies of the anions HCOOand C 6 H 5 COOwere then evaluated using the relation where X -) HCOOand C 6 H 5 COO -…”

“…It is, therefore, of interest to study the opposing effects of these interactions on the preferential solvation of various ions in these mixtures. In earlier work from this laboratory, the selective solvation of silver(I) salts in methanol + NMP mixtures had been reported (Varadarajan et al, 1997). In continuation of the above studies, the present work studies the solvation behavior of copper(II) iodate, copper(II) formate, and copper(II) benzoate by standard Gibbs transfer energy measurements of the salts and the corresponding ions and the solvent transport numbers for various salts over the complete range of solvent compositions.…”