Netsu Sokutei, 35 (3), p. 148, (2008)



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

環境負荷の低いフッ素系有機溶媒を含む31種類の2成分溶液について,過剰モルエンタルピーと過剰モル体積を測定した。それらの結果からフッ素有機溶媒の熱力学的性質を明らかにした。その結果,ハイドロフルオロエーテルはアルカンのような無極性物質との溶解においては,熱的な不安定化が大きくなるために混合のエントロピー効果によってかろうじて溶解している程度である。むしろ,ハイドロフルオロエーテルは極性物質の方がよく溶解する。また,フルオロアルコールについても同様にアルコールのような極性物質を積極的に溶解することが明らかになった。 さらに,この研究の知見を応用し,工業技術的な課題である洗浄・乾燥技術の分野におけるシミ発生の防止対策を試みた結果についても参考に述べた
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 (HmE) and volumes (VmE) 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 HmE and VmE results for the binary mixtures containing HFE were in positive, except for the HmE of HFE + MEK system. HmE value for the TFE + water system showed endothermic mixing, except for the low TFE concentration range. On the other hand, VmE values for this system were negative over the whole range of concentration. HmE values for all the TFE + alcohol systems were exothermic and VmE values of these systems were in positive over the whole range of concentration. Excess partial molar enthalpy (Hm,iE,∞) and volume (Vm,iE,∞) 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.