AN AUTOMATED VOLUMOMETER - THERMODYNAMIC PROPERTIES OF 1,1-DICHLORO-2,2,2-TRIFLUOROETHANE (R123) FOR TEMPERATURES OF 278.15 TO 338.15-K AND PRESSURES OF 0.1 TO 380 MPA

An automated bellows volumometer is described which is capable of obtaining p-V-T data in the form of volume ratios for pressures up to 380 MPa. Volume ratios for 1,1-dichloro-2,2,2-trifluoroethane (R123) have been measured for six temperatures in the range of 278.15 to 338.15 K in the liquid phase. The accuracy of the volume ratios is estimated to be +/- 0.05 to 0.1% for the experimental temperatures up to 298.15 K and better than +/- 0.15% for temperatures above the normal boiling point of R123 (300.15 K). They agree with the literature data (which do not extend beyond 4 MPa) within the experimental uncertainty of those results. Isothermal compressibilities, isobaric expansivities, internal pressures, and isobaric molar heat capacities have been evaluated from the volumetric data. The pressure dependence of isobaric molar heat capacities obtained from the data generally agree with the pressure dependence of experimentally measured literature values within the latter's accuracy of +/- 0.4%.