High-pressure phase behavior of the binary system isobutane plus diamantane

Solid-liquid and vapor-liquid equilibria for the binary system isobutane diamantane were determined according to the synthetic method in the tempera ture range (320-530) K and the pressure range (0.3-10) MPa. Also, the three -phase curve solid diamantane-liquid-vapor was determined. The results show that the slope of this curve demonstrates a discontinuity, which can be ex plained by the existence of two solid modifications of diamantane. The two branches of this equilibrium intersect at the S-1-S-2 equilibrium line of d iamantane. The influence of the occurrence of two modifications of diamanta ne on isobaric solid-liquid equilibria is less distinct.