difluoroethane (HFC152a) in pentaerythritol tetranonanoate, pentaerythritol tetra-2-ethylbutanoate, and pentaerythritol tetra-2-ethylhexanoate have been measured at temperatures between 303 and 363 K and pressures between 0.07 and 2.1 MPa. Henry's constant and the activity coefficient for HFCs at infinite dilution were derived for measurements below 0.34 MPa. The measurements were made by an isochoric method with an uncertainty of <2% for Henry's constant and <3% at high pressure. Within the investigated temperature range, solubilities for HFCs in pentaerythritol tetraalkyl esters decrease in the following order: HFC152a > HFC134a > HFC32 > HFC125 > HFC143a. The experimental data have been correlated with a Flory-Huggins model with an extended temperature dependence, which is able to describe the data with a deviation from measured data of <2.7%.

Solubilities of five different hydrofluorocarbons (HFCs) in a pentaerythritol tetrapentanoate ester (95% purity) have been measured at temperatures between 303.15 and 363.15 K and pressures between 0.05 and 1.9 MPa. Henry's constant and the activity coefficient for HFCs at infinite dilution were derived for measurements below 0.26 MPa. The measurements were made with an isochoric method with an uncertainty of less than 2% for Henry's constant and less than 3% at high pressure. Within the investigated temperature range, solubilities for HFCs decrease in the following order:  HFC152a > HFC134a > HFC32 > HFC125 > HFC143a. The experimental data have been correlated with a Flory−Huggins model with an extended temperature dependence, which is able to describe the data with a deviation from measured data of less than 2%.

The solubility of I , I , I , 2,2-pentafluoroethane (HFC125), I , I , 1,2-tetrafluoroethane (HFCI34a). 1. 1, 1 -trifluoroethane (HFC143a) and 1 ,I -difluoroethane (HFCI 52a) in four well-known hydrocarbons have been measured at temperatures between 293.15 and 363.15 K and pressures between 0.05 and 2 MPa. Henry's constant, and the activity coefficient for HFCs at infinite dilution, have been derived for measurements below 0.28 MPa. The measurements were made with an isochoric method and their uncertainty is less than 2% for Henry's constant and less than 3% at high pressure. For several mixtures, the experimental data have been correlated with the UN/QUAC method and binary interaction parameters have been derived, resulting in a deviation from the data of less than 4%.

A method for calculating the vapor−liquid equilibria of mixtures between hydrofluorocarbons and lubricant oils is presented. A cubic equation of state is used (Sako, T.; et al. J. Appl. Polym. Sci. 1989, 38, 1839), containing three parameters:  the attractive one, a, the volume parameter, b, and the number of external degrees of freedom per molecule, c. To allow calculation of the parameters of the high molecular weight components, whose critical constants and vapor pressure are unknown, a group-contribution approach is developed for a, b, and c. The extension to mixtures is achieved by applying Huron−Vidal mixing rules. A modified Uniquac model is used to evaluate infinite-pressure activity coefficients. With the proposed method, the density of pure heavy components (such as n-hexadecane and pentaerythritol esters) is predicted as a function of temperature. Vapor−liquid equilibria calculations are presented for binary mixtures between several hydrofluorocarbons and pentaerythritol esters or hexadecane; a comparison with the results obtained by available models is also outlined.

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