Topological investigations of the molecular species and molecular interactions that characterize pyrrolidin-2-one + lower alkanol mixtures

Abstract

Molar excess volumes, V E, molar excess enthalpies, H E, and speeds of sound data, u, of pyrrolidin-2-one ( i) + ethanol or propan-1-ol or propan-2-ol or butan-1-ol ( j) binary mixtures have been determined over entire composition range at 308.15 K. The observed speeds of sound data have been utilized to predict excess isentropic compressibilities, κ S E of the investigated binary mixtures. The observed excess thermodynamic properties V E, H E and κ S E have been analyzed in terms of Graph theory. The analysis of V E data by the Graph theory suggests that pyrrolidin-2-one exists mainly as a mixture of cyclic and open dimer; ethanol as a mixture of dimer and trimer; butan-1-ol and propan-2-ol as mixture of monomer and dimer and propan-1-ol as a dimer in the pure state, and their mixtures contain 1:1 molecular complex. The IR studies lend additional credence to the nature and extent of interactions for the proposed molecular entities in the mixtures. Also, it has been observed that V E, H E and κ S E values predicted by the Graph theory compare well to with their corresponding experimental values.