Volume-related solvation and pair interaction parameters for dilute solutions of urea and tetramethylurea in ethylene glycol between 288.15 K and 328.15 K: A comparative analysis.

• Densities of urea and tetramethylurea solutions in ethylene glycol were measured at (288.15–328.15) K and p = 99.6 kPa. • Standard partial molar volumes and isobaric expansibilities and pair interaction coefficients for solutes were computed. • A structure packing of solvation complex becomes denser on going from TMU to U and, in a less degree, from EG to water. • Coefficients of solute – solute interactions are positive for U and negative for TMU in EG, decreasing with temperature. • Temperature has differentiating effect on trends of changing standard partial expansibility of U and TMU as solutes in EG. The densities of urea (U) and tetramethylurea (TMU) solutions in ethylene glycol (EG) at the solute molality range up to 1.5 mol·kg−1 were measured with the uncertainty of 0.03 kg·m−3 at T = (288.15, 298.15, 308.15, 318.15 and 328.15) K and p = 99.6 kPa using a vibrating-tube densimeter. The standard partial molar volumes and isobaric expansibilities as well as parameters of the solvent-induced solute–solute pair interactions for both ureas were calculated. The results were discussed in terms of hydrophilic and hydrophobic nature of U and TMU, respectively, and also on the background of the suggestion that EG, like liquid water, forms the hydrogen bond spatial network. [ABSTRACT FROM AUTHOR]