Density and Viscosity Measurements of n-Dodecane and Carbon Dioxide plus n-Dodecane at Temperatures from (298 to 548) K

A vibrating-wire apparatus was used to measure liquid density and viscosity simultaneously under high-temperature conditions. Densities and viscosities were measured along 11 isotherms at temperatures from (298.15 to 548.15) K and pressures up to 10 MPa for n-dodecane, and over a temperature range of (303.15 to 548.15) K and at equilibrium pressures up to about 6 MPa for carbon dioxide + n-dodecane. The estimated combined expanded uncertainties are 0.24 % for density and 2.2 % for viscosity with a confidence level of 0.95 (k = 2). In addition, experimental density and viscosity data were correlated with the modified Tait equation and Tait-Andrade equation, respectively, and comparisons with literature data were made. With regard to n-dodecane, the equations present both literature data and our experimental results with deviations almost within 0.2 % for density, and 3.0 % for viscosity. For simplicity, the experimental data of carbon dioxide + n-dodecane were correlated using these two Tait-like equations directly without considering the mole fraction of CO2. Both correlations describe our measured data of carbon dioxide + n-dodecane almost within 0.2 % for density and 1 % for viscosity.