Bubble pressure measurements for the (1,1,1,2-tetrafluoroethane plus 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 center dot 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. (c) 2006 Elsevier Ltd. All rights reserved.