PHASE-EQUILIBRIA IN BINARY-MIXTURES OF PROPANE AND HEXACONTANE

This paper reports on the phase behaviour of binary mixtures of propan e with hexacontane (n-C60H122). The measurements cover a temperature r ange from about 310 K up to 430 K. Pressures up to 15 MPa were applied . In the binary propane + hexacontane, a three-phase equilibrium liqui d + liquid + vapour (l1 l2g) occurs in the near-critical region of pro pane. However, in this system the lower critical end point (LCEP) was hidden by solidification of hexacontane. The pressure temperature coor dinates of the upper critical end point were determined at 369.95 K an d 4.275 MPa. Because the three-phase equilibrium l1 l2 g is interrupte d by the three-phase equilibrium, solid hexacontane + liquid + vapour (s(B)l(g)), a Q-point solid hexacontane + liquid + liquid + vapour (s( B)l1 l(2)g) is present in this binary. Its pressure and temperature co ordinates were located at 352.0 K and 3.05 MPa.