
%0 Journal Article
%A Clare, BW 
%A Singh, P 
%A Mangano, P 
%A Parker, AJ 
%A Muir, DM 
%T Hydrometallurgical thermodynamics. I. Effect of sulfate ion-pairing and ion-solvation on the copper-iron redox equilibrium in aqueous acetonitrile
%J Australian Journal of Chemistry
%D 1983/09/01
%V 36
%N 9
%P 1687-1694
%K 
%R https://doi.org/10.1071/CH9831687
%U https://www.publish.csiro.au/paper/CH9831687 
%X The copper-iron redox equilibrium is shifted to the right CuII+FeII&#8596;CuI+FeIII by strong ion-pairing of sulfate ion with FeIII and by specific solvation of CuI with acetonitrile. The equilibrium constant has been measured by direct e.m.f. and spectroscopic methods between pH 0-2 and found to be about 107 higher for practical solutions of sulfates in acetonitrile/water than that calculated for perchlorates in pure water. Enthalpies and free energies of transfer of these ions from water to acetonitrile/water show that the shift in equilibrium to Cul+FeIII in acetonitrile/water solution is strongly favoured by enthalpy changes associated with copper(I)-acetonitrile ion-solvation. Ion-pairing of sulfate ion with iron(III) results in an increase in entropy and a small shift of the equilibrium to the right. 
