Phase equilibria are reported for the following four systems: 1,2-dichloroethane (CASRN 107-06-2) + trans-1,2-dichloroethylene (CASRN 156-60-5) at 30 degrees C and 80 degrees C; 1-octene (CASRN 111-66-0) + 2-methyl thiophene (CASRN 554-14-3) at 100 degrees C and 140 degrees C; 2-ethyl thiophene (CASRN 872-55-9) + 2,2,4-trimethylpentane (CASRN 540-84-1) at 100 degrees C and 140 degrees C; cyclopropanecarbonitrile (CASRN 5500-21-0) + water (CASRN 7732-18-5) at 100 degrees C and 135 degrees C. The system pressure and temperature were measured at several charge compositions along a given isotherm for each system. Equilibrium vapor- and liquid-phase compositions were derived from the measured PTx data using the Soave equation of state to represent the vapor phase and the NRTL activity coefficient model to represent the liquid phase. Two liquid phases are present with the cyclopropanecarbonitrile + water system at 100 degrees C. Vapor-liquid-liquid equilibrium data were measured at this condition. Multiple samples were withdrawn and analyzed from each equilibrium phase. A second liquid phase is not present with this system at 135 degrees C. PTxy measurements were performed at this temperature in order to better define the azeotropic composition. Multiple samples were withdrawn and analyzed from the equilibrium vapor and liquid phases at three liquid compositions near the azeotrope.