Bubble pressure measurements for the (1,1,1,2-tetrafluoroethane + triethylene glycol dimethyl ether) system

A computer-operated static apparatus has been used for the measurement of the bubble pressures of the (1,1,1,2-tetrafluoroethane + triethylene glycol dimethyl ether) system at temperatures between (283 and 323) K in the composition range where the first component is prevailing, i.e., mainly for a mole fraction in the liquid phase greater than 0.7. The chosen ranges cover the most interesting conditions for the technical applications of such a mixture in refrigeration plants. The obtained experimental data constitute a set of 125 points distributed along five isotherms. The data have been correlated using a Wilson model for the activity coefficient, reaching satisfactory results; in fact the average absolute value of the relative deviation of the experimental bubble pressure from the model is 0.16 · 10−2. At high temperatures, the mixtures with low content of triethylene glycol dimethyl ether show positive deviations from Raoult’s law, whereas the other cases are characterized by negative deviations.