Ultrasonic and 31P NMR investigations of an acidic nuclear extractant with some monosubstituted benzenes

The ultrasonic velocity, density and viscosity of an acidic nuclear extractant namely di(2-ethylhexyl) phosphoric acid (D2EHPA) and its binary mixtures with three monosubstituted benzenes, viz., nitrobenzene, chlorobenzene and toluene were determined at temperature T = 303.15 K and at pressure p = 0.1 MPa. The experimental values were utilised to compute relaxation time, excess molar volume, excess Gibbs energy of activation of viscous flow, deviations in intermolecular free length, acoustic impedance, ultrasonic velocity and viscosity. The excess/deviation functions were fitted to fourth order Redlich-Kister type polynomial equation to estimate binary coefficients and standard errors between experimental and calculated data. The nature of these functions was utilised to speculate the nature of molecular interaction between component molecules of all studied binary mixtures. Furthermore, 31P NMR spectra of pure D2EHPA and its binary mixtures with the monosubstituted benzenes were used to assess molecular interactions between components of liquid mixtures at microscopic level and to corroborate with the results obtained from bulk properties of liquid mixtures.