Measurement and correlation of the (p, ρ, T) relation of ethane II. Saturated-liquid and saturated-vapour densities and vapour pressures along the entire coexistence curve

Comprehensive and accurate measurements of the saturated-liquid and saturated-vapour densities together with the vapour pressure of pure ethane were carried out from the temperature T=91 K (triple-point temperature Tt=90.368 K) to 0.022 K below the critical temperature. Typical values of the total uncertainties of the measurements are: ±0.01% for the vapour pressures, ±0.015% for the saturated-liquid densities, and ±0.02% for the saturated-vapour densities. The critical parameters (Tc=305.322 K; , pc=4.8722 MPa) and the isothermal compressibilities in the critical region close to the phase boundary have also been determined from these measurements. Comparisons with experimental results of other workers are presented. Using the new data of this work, new correlation equations for the vapour pressure, the saturated-liquid density, and the saturated-vapour density have been developed.