Liquid Viscosities of Cyclohexane, Cyclohexane plus Tetradecane, and Cyclohexane plus Benzene from (313 to 393) K and Pressures Up to 60 MPa

Liquid viscosities of pure cyclohexane and of the cyclohexane + tetradecane and cyclohexane + benzene systems at four different compositions were measured using a rolling-ball viscometer from (313.2 to 393.2) K and pressures Lip to 60 MPa with an estimated experimental uncertainty in the measured viscosity data of 2 %. A comparison between our measured viscosities and those reported by others authors for cyclohexane was established with the hard-sphere scheme given by Assael et al. [Int. J. Thermophys. 1992, 13, 269-281]. The comparison showed an average relative deviation of 2.3%. The measured mixture viscosity data were regressed with the correlations of Grunberg-Nissan (GN) and Katti-Chaudhri (KC), and a liquid viscosity model based on Eyring's theory coupled with a cubic equation of state (ET-EoS), all of them using a single temperature-independent binary interaction parameter to describe the whole eta, T, p, x surface of study. Results of the representation with the GN, KC, and ET-EoS viscosity models yielded, respectively, average relative deviations of (3.4, 3.8, and 3.5) % for the cyclohexane + tetradecane system and of (3.1, 3.0, and 4.0) % for the cyclohexane + benzene system, showing that these viscosity models are capable of representing satisfactorily the experimental viscosity behavior of these systems over the whole temperature, pressure, and composition range studied. Furthermore, two viscosity approaches with a physical and theoretical background (the hard-sphere scheme and the free-volume model) were used for modeling the viscosities of the two binary systems studied. Results Of the modeling with the hard-sphere and free-volume viscosity models yielded, respectively, average relative deviations of (4.0 and 26.1) % for the cyclohexane + tetradecane and of (7.3 and 4.8) % for the cyclohexane + benzene system.