Studies on molecular interactions in aqueous and aqueous urea systems of paracetamol (N-(4-hydroxyphenyl) ethanamide)

Abstract

Density (d) and Ultrasonic velocity (U)have been measured in aqueous paracetamol and paracetamol + aqueous Urea in five different concentrations ranging from 0.01 M to 0.09 M at 0.02 M interval. Densities of these solutions were measured over the temperature range 298.15 K to 313.15 K at 5 K interval. The ultrasonic velocities (U) have been measured at 298.15 K only. Experimental density data have been used to estimate various important parameters, such as apparent molar volume (Vɸ), limiting apparent molar volume (Vɸ0), apparent molar expansibility (Eɸ) and limiting apparent molar expansibility (Eɸ0). Further, from the ultrasonic data, different thermo-acoustical parameters, such as isentropic compressibility (Ks), apparent molar isentropic compressibility (Ks, ɸ), acoustic impedance (Z), molar compressibility (W), internal pressure (πi), free volume (Vf), molar sound velocity (R), free length (Lf), relaxation time (τ), absorption co-efficient (α/f2) and solvation number (Sn) have been calculated and explained in the light of solute-solute and solute-solvent interactions.