Ion-pair and triple-ion formation of some tetraalkylammonium iodides in n-hexanol and its binary mixtures with o-toluidine

The electrolytic conductivity of the tetraalkylammonium iodides, R4NI (R = butyl to heptyl), has been studied in (0.00, 0.25, 0.50 and 0.75) mass fraction of o-toluidine (C7H9N) in n-hexanol (C6H14O) at T = 298.15 K. The limiting molar conductance Lambda(0), association constants K-A and the co-sphere diameter R for ion-pair formation in 0.00 and 0.25 mass fraction of solvent mixture have been evaluated using the Fuoss-equation. However, the deviation of the conductometric curves (Lambda versus c(1/2)) from linearity for the electrolytes at 0.50 and 0.75 mass fraction of o-toluidine (C7H9N) in n-hexanol (C6H14O) indicates triple ion formation, and therefore the corresponding conductance data have been analyzed by the Fuoss-Kraus theory of triple ions. The observed values of the molar conductivity are explained by the ion-pairs (M+ + X- <-> MX) and triple-ions (2M(+) + X- <-> M2X+, M+ + 2X(-) <-> MX2-) formation. From the investigations, the following trend in conductance of the solvated salts has been observed: [GRAPHICS] (C) 2010 Elsevier Ltd. All rights reserved.