Ion pairing in protic and aprotic solvents of intermediate dielectric constant at 25°C

Abstract

The conductances of tetramethylammonium and tetrahexylammonium perchlorates in acetonitrile and of tetramethylammonium and tetraethylammonium perchlorates in methanol have been measured at 25°C. These data combined with other literature data allow an analysis of the association behaviour of perchlorate salts with cations of different sizes in the isodielectric solvents methanol and acetonitrile. The association constants found in methanol differ in magnitude and in cation dependence from those in acetonitrile. These results are discussed in terms of the influence of ion-solvent interactions on ion pairing.