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Measurements of the viscosity and density versus temperature and pressure for the binary system methylcyclohexane + 2,2,4,4,6,8,8-heptamethylnonane
Claus Zéberg-Mikkelsen, Mohammed Barrouhou, Antoine Baylaucq, Christian Boned

Measurements of the viscosity and density of seven binary mixturescomposed of methylcyclohexane + 2,2,4,4,6,8,8-heptamethylnonane along with the pure compounds have been performed in the temperature range 293.15 – 353.15 K and up to 100 MPa. The viscosity was measured up to 100 MPa with a falling-body viscometer, except at 0.1 MPa where a classical capillary viscometer was used. The experimental uncertainty for the measured viscosities is 2%. The density was measured up to 60 MPa with a resonance densimeter and extrapolated with a Tait-type relationship up to 100 MPa. The accuracy of the reported densities is better than 1 kg m-3. On the basis of the obtained data, an analysis of the excess activation energy for viscous flow versus temperature, pressure, and composition has been performed, showing that the excess activation energy for viscous flow is positive with a maximum value of 700 J mol -1, corresponding to a weakly interlinking system. In addition, simple mixing laws (Grunberg – Nissan and Katti – Chaudhri) have been evaluated in order to analyse the possibility of estimating the viscosity of the binary system under consideration from the viscosity and density of the pure compounds.

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