Solidification and viscosity of iso-pentane/n-pentane mixtures at low temperatures and high pressure

It is found that mixtures between iso- and n-pentane have a minimum in the melting line for a composition of 5 : 1 iso/n-pentane. At ambient pressure, this liquid transforms from a viscous fluid to a clear solid between ∼95 K and ∼85 K. We report measurements of the solidification line and approximate viscosity values of this mixture up to 3 kbar in the temperature range 90–130 K using the 'blocked capillary' technique. The results suggest that the 5 : 1 iso/n-pentane mixture may have important applications as a cryogenic hydraulic liquid as well as a pressure transmitting medium in low temperature research.