Substituent Effect on the Association Phenomenon of an Aqueous Solution of Benzylidene Substituted Aniline at Different Temperatures


Conductivity parameters of an aqueous solution of benzylidene substituted anilines (I-IV) have been determined at five different temperatures in the range of 283.15-318.15 ºK, through accurate conductance measurements. The obtained data were analyzed in accordance to Lee-Wheaton equation taking into account the activity of the electrolyte in the solution. The conductance measurement results were used to determine the association constants (KA) of ion-pairs, the mean distance between ions in solution, in addition to the molar conductance at infinite dilution (Λo¬) for the free ion in the solution. The dependence of (KA) values on the temperature has been examined by plotting Log KA against the reciprocal values of temperature (1/T), which showed linear relationship, where (KA) values decrease with increasing temperature. Moreover, the enthalpy (ΔH), Gibbs free energy (ΔG) and the entropy (ΔS) have been derived from this linear relationship.