Calculation of the activity coefficients at infinite dilution in binary aqueous systems of pyridine and its derivatives

Abstract

The activity coefficients at infinite dilution of binary mixtures formed by water and pyridine and its derivatives (2-methylpyridine, 3-ethylpyridine, 2,4,6-trimethylpyridine) have been calculated using the NRTLmKW model. The calculation have been performed for experimental isothermal data measured at T=353.15K in a very narrow range of concentration using the ebulliometric method. The calculated activity coefficients have been compared with the activity coefficients at infinite dilution obtained directly from the measured vapour pressures. The obtained results have been fully discussed from the point of view of intermolecular interactions in the solutions and some recommendations have been made on the use of the NRTLmKW model for such calculation.