Simultaneous Viscosity and Density Measurements and Modeling on Liquid Undecane, Dodecane, Tridecane, and Tetradecane up to 50 MPa

In this study, simultaneous experimental measurements of dynamic viscosity and density of four Newtonian liquids (undecane, dodecane, tridecane, and tetradecane) were performed in the pressure range from 1.99 to 50.01 MPa, along five isotherms between 298.15 and 353.16 K. The dynamic viscosity and density were determined using the capillary flow technique and a vibrating tube densimeter, respectively. The viability of the methods used was verified through the experimental measurements of the viscosity and density of ethanol and its comparison with data published in the international literature, resulting a maximum deviation of 1.25% for viscosity and 0.58% for density. The relative combined expanded uncertainty (k = 2) for the experimental measurements was estimated to be 1.4% and 0.2% for dynamic viscosity and density data, respectively, considering the impurities of the chemical compounds. Also, two empirical models were used to represent the experimental data reported in this work; for the dynamic viscosity, a maximum deviation of 0.5% was found, while, for density, a maximum deviation of 0.11% was obtained. From density data and using the empirical model, the isothermal compressibility and isobaric thermal expansivity were evaluated under the reported conditions.