An Experimental Study of the pVTx Properties for Aqueous Solutions of Ammonia Focusing on the Maximum Density Region

An experimental study of the pressure–volume–temperature-composition (pV T x) properties for the aqueous solution of ammonia, namely NH3–H2O mixtures, has been conducted with the use of a constant-volume apparatus, especially focusing on the maximum density behavior, in the range of temperatures from 253 to 309 K, pressures from 0.47 to 16.93MPa, densities from 950 to 1007 kg ·m−3 and compositions from 0 to 0.1436 mole fraction of ammonia. The behavior of the maximum densities for the aqueous solution of ammonia has been investigated for the first time by the present experimental study, and the available equations of state do not represent the pVTx properties of the present measured data adequately near the maximum density region.