The present work deals with a measurement system for densities of compressed liquids over the temperature range of 263-473 K and pressure up to 70 MPa. The functionality of the installation is based on the usage of a commercial vibrating tube densimeter DMA HP. Calibration of the DMA HP cell was performed by two methods in which a vacuum, water, toluene, and aqueous solution of NaCl were used as calibration fluids. The density at high pressures of 2-pyrrolidone was measured in the range of 0.1-70 MPa at two different temperatures (308.15 and 323.15) K, and that of water-2-pyrrolidone mixture was measured in the entire composition range of the mixture liquid state in the range of 0.1-70 MPa at five different temperatures - from (278.15 to 323.15) K. Density data were fitted by Tait-type equation where the absolute average percentage deviation between measured and calculated densities was about 0.02%. These data were later used to calculate the excess molar volumes, V-m(E), partial molar volumes of water, V-1 and 2-pyrrolidone V-2, and to obtain the limiting partial molar volumes of components V-1(infinity). Structure-property relationships were analyzed, the effects of temperature and pressure on these properties were also discussed.
