3.1 ABSTRACT The intermolecular interactions in the N-methylformamide with acetophenone, cyclic ketones (cyclopentanone and cyclohexanone) binary liquid systems are studied in combined experimental and computational methodology. The speed of sound (u), density (ρ) and viscosity ( ) values are measured for binary mixtures of N-methylformamide with ketones over the entire range of mole fraction at temperatures T= (303.15 to 318.15) K, at atmospheric pressure. From the experimental results, the values of excess molar volume ( ), excess isentropic compressibility (κsE), deviation in viscosity (η) and excess Gibbs free energy of activation of viscous flow ( ) are evaluated. The experimental results indicate the intermolecular association between the binary liquid …show more content…
The appropriate combination of dissociation of the components due to the addition of the second component, the existence of weak forces between unlike molecules and differences in sizes and shapes of the components affects the sign and magnitude of the excess isentropic compressibilities [32].
The values in liquid mixtures depends on the molecular structure of component liquids, and influenced by other factors like dipole-dipole interactions, hydrogen bonding, and charge transfer interactions and or complex formation.
An examination of data in Table 4 cause that the factors causes for negative excess isentropic compressibilities were dominant in the binary mixtures of N-methylformamide with ketones at (303.15 to 318.15) K.
The observed negative values indicate that dipole-dipole interaction between unlike molecules is stronger than N-methylformamide- N-methylformamide or ketone-ketone interactions in all the systems under study [33].
The algebraic values fall in the order cyclopentanone > cyclohexanone >