Experimental study of the density and derived partial molar volumes of complex ternary water + 1-propanol + Li2SO4 mixtures at temperatures from (303 to 448) K and pressures up to 40 MPa

Densities of complex ternary water + 1-propanol + Li2SO4 mixtures have been measured over the temperature range from (303 to 448) K and at pressures up to 40 MPa using the constant-volume piezometer immersed in a precision liquid thermostat. The measurements were performed for nine samples with concentrations of Li2SO4 from (0.00623 to 0.0274) mole fraction and concentrations of 1-propanol from (0.01553 to 0.05024) mole fraction. In this work the mole fraction of 1-propanol is given in the electrolyte (Li2SO4)-free solution. The combined expanded uncertainty of the density, pressure, temperature, and concentration measurements at the 95% confidence level with a coverage factor of k = 2 is estimated to be 0.06%, 0.05%, 20 mK, and 0.015%, respectively. Measured values of density for ternary mixtures were used to calculate partial molar volumes of alcohol (1-propanol), ( V ¯ 1 ), and salt (Li2SO4), ( V ¯ 2 ). The temperature and pressure dependences of the partial molar volumes were studied. The concentration dependences of the partial molar volumes were extrapolated to zero concentration (x1 → 0 in alcohol dilute mixture and x2 → 0 salt dilute mixture) to yield the partial molar volumes of alcohol ( V ¯ 1 0 ) and salt ( V ¯ 2 0 ) at infinite dilutions.