Thermodynamics of aggregation of some tertiary n-alkylammonium picrates in benzene solutions

Abstract

The practical molal osmotic coefficients, molal activity coefficients and thermodynamic excess functions of tri-n-propylammonium picrate, tri-n-butylammonium picrate, tri-n-pentylammonium picrate in benzene solutions over the concentration range 0.005–0.25 mol kg^–1 were determined by vapour pressure osmometry. The non-ideal behaviour of the investigated systems was interpreted on the basis of an association model including an extended series of multimers. The heat of infinite dilution in terms of the standard enthalpy of the self-association reaction qB⇌Bq and molal concentration of oligomeric species was evaluated and compared with the excess enthalpy values.