Thermodynamic Properties of Binary Mixtures Containing Several Kinds of Organic Fluorine Compounds

Abstract

 A number of fluorinated organic compounds has been synthesized and utilized as the alternative solvent to the chlorofluorocarbons. In order to discuss the solvent performance of hydrofluoroether (HFE) and trifluoroethanol (TFE) in aspect of the thermodynamic properties, excess molar enthalpies (H_m^E) and volumes (V_m^E) have been determined for binary mixtures containing them at 298.15 K using a home-made twin conduction type of flow microcalorimater equipped with a pair of precision cylinder pumps and Anton-Paar vibrating tube densimeter. The first component liquid of HFE-356mec (CF₃CHFCF₂OCH₃), HFE-347pc-f (CHF₂CF₂OCH₂CF₃) and HFE-449 (C₄F₉OCH₃) and TFE, and the second component liquid of several different types of organic solvents were distilled with 1m packed column.
 The H_m^E and V_m^E results for the binary mixtures containing HFE were in positive, except for the H_m^E of HFE ＋ MEK system. H_m^E value for the TFE ＋ water system showed endothermic mixing, except for the low TFE concentration range. On the other hand, V_m^E values for this system were negative over the whole range of concentration. H_m^E values for all the TFE ＋ alcohol systems were exothermic and V_m^E values of these systems were in positive over the whole range of concentration. Excess partial molar enthalpy (H_m,i^E,∞) and volume (V_m,i^E,∞) at infinite dilution were also estimated. These results were discussed qualitatively from the viewpoint of the difference in intermolecular interactions between the pure component liquids and the mixtures. HFE and TFE are expected to be a good solvent especially for the polar solvent materials in the cleaning technology of electronic industries.