EXCESS VOLUMES AND ISENTROPIC COMPRESSIBILITIES OF PYRROLIDIN-2-ONE-ALKANOL (C-1-C-5) BINARY-MIXTURES

The velocity of sound, u, and excess volume, V-E, have been determined at 303.15 K for binary mixtures of pyrrolidin-2-one + n-alkanol (C-1- C-5) over the whole composition range. The isentropic compressibilitie s K-S and their excess values K-S(E) have been estimated and shown to be negative for all systems over the entire composition range and to v ary in the order methanol < ethanol < propanol < butanol < pentanol. T he V-E results have been used to estimate the excess partial molar vol umes of the components and have also been analysed in the light of Pri gogine-Flory-Patterson theory. An analysis of each of the three contri butions viz. interactional, free volume and P to V-E shows that the i nteractional contribution is positive for all systems except methanol which has a small negative interactional contribution. The free volume effect and P contribution are negative for all the mixtures. To expl ore the nature of the interactions, various thermodynamic parameters i .e. free volume, V-f, solvation number, S-n, Wada's constant W, and Ra o's constant, R, have been derived from the u and rho data. The behavi our of these parameters indicates the absence of any complex formation in the mixtures studied.