DESIGN OF A HIGH-PRESSURE EBULLIOMETER, WITH VAPOR-LIQUID-EQUILIBRIUMRESULTS FOR THE SYSTEMS CHF2CL-CH3 AND CF3-CH2F+CH2F2(CF3)

We describe the design and operation of a new high-pressure metal ebul liometer which can operate at pressures to at least 3 MPa in the range 220-400 K. Infinite-dilution activity coefficients are presented for the system CHF2Cl+CF3-CH3 at 275 K and for the system CF3-CH2F+CH2F2 a t 260, 280, and 300 K. The Wilson activity coefficient model and a vir ial coefficient model are applied to these systems, and the phase equi librium conditions are calculated. The results are shown to agree well with predicted and with published measured values. The excess enthalp y is calculated and compared with results from a Peng-Robinson equatio n of state. Vapor densities on the dew curves are given.