Influence of substitution in the aromatic ring on the behaviour of thermodynamic properties of pyrrolidin-2-one and aromatic hydrocarbons

Abstract The excess volume, V E and velocity of sound, u have been measured for the mixtures of pyrrolidin-2-one and aromatic hydrocarbons ( o -xylene, m -xylene, p -xylene and ethylbenzene) over the entire range of composition at 303.15 K. V E values are negative for all the mixtures and vary in the order: o -xylene>ethylbenzene> m -xylene> p -xylene. The results have been analysed by using the well-known Prigogine–Flory–Patterson theory. Molar isentropic compressibility K S and its excess values K S E have been obtained from the ultrasonic velocity data in combination with density values (calculated from excess volume). The K S E is negative for all the systems over the entire range of composition and vary in the order o -xylene> m -xylene>ethylbenzene> p -xylene. The partial and apparent quantities have also been estimated. The results are compared and discussed to gain insight into the interactions between the respective components.