Densities and Volumetric Properties of Aqueous Solutions of {Water (1) + N-Methylurea (2)} Mixtures at Temperatures of 274.15–333.15 K and at Pressures up to 100 MPa

Abstract

Densities of the mixture {water (1) + N- methylurea (2)} in the concentration range to mole fraction x2 = 0.07071 (or to the solution molality concentration m2 = 4.22335 mol·kg–1) at atmospheric pressure in the temperature range from 274.15 to 333.15 K and compression k = ΔV/V0 at pressures to 100 MPa (10, 25, 50, 75, and 100) in the temperature range from 278.15 to 323.15 K (278.15, 288.15, 288.15, 308.15, 323.15) in the same concentration range were calculated in this study. The apparent molar volumes of N-methylurea Vϕ,2 and the partial molar volumes of both components V̅1 and V̅2 in the mixture, molar isothermal compressibilities KT,m, molar isobaric thermal expansions EP,m, and isochoric coefficients of thermal pressure β of the mixture were calculated. Moreover, volumetric measures for the infinitely dilute solution of N-methylurea solution were calculated: limiting partial molar volumes V̅2∞, the limiting partial molar isothermal compressibilities K̅T,2∞, and the limiting partial molar isobaric thermal expansions E̅P,2∞. The results obtained are discussed from the point of view of solute–solvent and solute–solute interactions.