Reference Correlation of the Viscosity of n-Propyl Alcohol from 153 to 618 K and up to 118 MPa

A reference correlation for the viscosity of n-propyl alcohol was developed based on carefully selected primary experimental data. The correlation, formulated as a function of temperature and density, covers the temperature range from 153–618 K and pressures up to 118 MPa. Comparison between the correlation and the experimental data showed an average absolute relative deviation of 1.01% and a bias of −0.18% for the data under pressure, while the values of 0.75% and +0.01% were observed for data close to 0.1 MPa. The expanded uncertainty (with coverage factor k = 2) of the reference correlation in the liquid phase was estimated to be 2.0% close to 0.1 MPa and 2.5% under pressure. In the supercritical region, the expanded uncertainty (k = 2) was estimated to be 4.2%. The uncertainty was estimated doubled relative to the nearby region when no primary data exist. In the gaseous phase, the expanded uncertainty (k = 2) was estimated to be 2.2% above 373 K and 4.6% below 373 K. The uncertainty in the critical region may be larger because of the lack of experimental data. Additionally, an empirical equation valid from 153–363 K and at pressures of 0.1 MPa was proposed, with an estimated expanded uncertainty of 2.0% (k = 2).