Solutions of three hydrocarbons in liquid methane

Abstract

The phase boundary of the liquid states of the system methane+hex-1-ene show an upper critical solution temperature at 133.8°K and a lower critical solution temperature at 179.6°K. Such behaviour has been found previously only for polymer solutions. Volumes of mixing of methane +i-pentane and methane+2-methyl pentane have been measured from 115 to 155°K. The contraction is so great that the apparent partial molar volume of methane is negative at high temperatures and infinite dilution. The excess free-energy of methane+2-methyl pentane has a maximum of +0.34 RT at 116°K, which is larger than that recently found for methane+propane.