The initial density dependence of the viscosity of organic vapours: Cyclohexane and neopentane

Abstract

This paper presents new measurements on the viscosity of the vapours of cyclohexane and of neopentane from near room temperature to 630 K and for densities to 4.8 kg m −3 and 0.057 mol 1 −1 (cyclohexane) and to 5.0 kg m −3 and 0.069 mol 1 −1 (neopentane). Two all-quartz oscillating-disk viscometers with small gaps were used in the investigation. The data for cyclohexane and neopentane as well as earlier results for benzene show that the negative and positive values of the second viscosity virial coefficient B η, dependent on temperature represent the normal behaviour for all substances. The experimental data on the three hydrocarbons are suitable for the further development of the Rainwater-Friend theory concerning the transport properties of moderately dense gases in respect to their temperature range and their limitation to the Lennard-Jones 12-6 potential.