Viscosity measurement of n-dodecane and n-hexane and their binary mixtures at combined high pressure and ambient and sub-ambient temperatures of 20oC and 5oC

We report the measurement of the viscosity of pure n-dodecane and n-hexane and their binary mixtures under combined conditions of high pressure up to 200 MPa and at ambient and sub-ambient temperatures of 20oC and 5oC. Using a thermostatically controlled falling sinker-type viscometer, reproducible and reliable viscosity data were obtained from terminal velocity sinker fall times. Liquid viscosities were found to increase exponentially with both rising pressure and reducing temperature according to the Barus equation. The Tait equation was used to determine compressed density and the Grunberg and Nissan equation used to predict the viscosity of mixtures. Additionally, pressure and thermal freezing were found to also occur with increasing pressure and lowering temperature.