Experimental study of the density and derived (excess, apparent, and partial molar volumes) properties of binary water + ethanol and ternary water + ethanol + lithium nitrate mixtures at temperatures from 298 K to 448 K and pressures up to 40 MPa

Abstract

Densities of binary water+ethanol and ternary water+ethanol+LiNO3 mixtures have been measured over the temperature range from 298K to 448K and at pressures up to 40MPa using the constant-volume piezometer immersed in a precision liquid thermostat. The measurements for water+ethanol mixture were made for four compositions of 0.0163, 0.0343, 0.0730, and 0.0946mol fraction of ethanol. The measurements for thernary water+ethanol+LiNO3 mixtures were performed in the same temperature and pressure ranges for twelve concentrations. 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%, 20mK, and 0.015%, respectively. The derived volumetric properties such as excess (VmE), apparent (VΦ), and partial (V¯2∞) molar volumes were calculated using the measured values of density for the binary water+ethanol mixture and for pure water and ethanol. The small and negative values of excess molar volume for the mixtures were found at all experimental temperatures, pressures, and over the entire concentration range. The excess molar volume minimum is found at concentration about 0.4mol fraction of 1-propanol. The concentration minimum of the derived apparent molar volumes VΦ near 2molkg−1 (dilute mixture) was observed.