Article pubs.acs.org/jced
Liquid−Liquid Equilibria for the Ternary Systems of Perfluorohexane + Methyl Nonafluorobutyl Ether + Toluene, + 1,4-Dioxane, or + Dimethylformamide at 298.15 K Ki Won Eum,† Hyemin Gu,† Tae Gyu Lee,‡ Jaehoon Choe,§ Kabsoo Lee,∥ and Kwang Ho Song*,†,‡ †
Department of Chemical & Biological Engineering, Korea University, Seoul 136-713, Korea Green School, Korea University, Seoul 136-713, Korea § LG Chem Research Park, Daejeon 305-380, Korea ∥ Department of Health & Environment, Kimpo College, Gyenggi-do 415-761, Korea ‡
ABSTRACT: Equilibrium tie-line data were determined for a fluorous biphasic systems at 298.15 K. Two phase mixtures were used, consisting of a perfluorinated solvent phase using a mixture of two fluorinated solvents (methyl nonafluorobutyl ether and perfluorohexane) as well as an organic solvent phase in which the organic solvents studied were toluene, 1,4dioxane, and dimethylformamide, respectively. Nonrandom two liquid models applied to the four ternary systems produced interaction parameters that were well-correlated with the equilibrium composition. These parameters enabled the prediction of liquid−liquid equilibrium systems containing methyl nonafluorobutyl ether and perfluorohexane. The ability to manipulate fluorous biphasic systems composed of perfluorohexane and an organic solvent with the addition of methyl nonafluorobutyl ether was examined.
1. INTRODUCTION Fluorinated solvents, mostly perfluorinated alkanes, perfluorinated dialkyl ethers, and perfluorinated trialkyl amines, have become increasingly popular in many areas of research. They have been used as solvents for fluorous reagents and fluorous substrates, as an alternative media to toxic chlorinated solvents. Fluorinated solvents become miscible with organic solvents at elevated temperatures; however, their extraordinarily high hydrophobicity causes them to form a bilayer with many organic solvents at lower temperatures. The use of a biphasic system allows easy product separation and recycling of the fluorocarbon tagged homogeneous catalysts, since fluorocarbon tagged catalysts are totally soluble in the fluorinated solvent phase, and a nonfluorous organic phase contains reactants and products with limited solubility in the fluorous phase.1 Fluorous/organic biphasic systems based on hydrofluoroethers (HFEs) with fluorocarbons have been introduced.2,3 HFEs were developed as alternatives to ozone-depleting compounds, such as chlorofluorocarbons and hydrochlorofluorocarbons, and have been used to replace many other solvents due to their zero ozone depleting potential and favorable physical and chemical properties, including low surface tension, nonflammability, and excellent solvating ability. Because HFEs have a fluoroalkyl group on one side of the ether oxygen and an alkyl group on the other, they can dissolve both fluorous compounds and organic solvents. The miscibility and mutual solubility of HFEs with an organic solvent can be adjusted by adding a fluorocarbon. In this study, ternary liquid−liquid equilibria (LLE) for methyl nonafluorobutyl ether + perfluorohexane + organic solvent such as toluene, 1,4-dioxane, and dimethylformamide © 2013 American Chemical Society
were studied as a mixture. Tie lines were measured for the ternary systems. The results of the measurements were correlated using the nonrandom two-liquid (NRTL) model.4
2. EXPERIMENTAL SECTION Toluene (99.9 %) was obtained from Avantor Performance Materials (Phillipsburg, NJ, USA). 1,4-Dioxane (99 %) and N,N-dimethylformamide (99.8 %) were obtained from SigmaAldrich (St. Louis, MO, USA). Methyl nonafluorobutyl ether (99 %, HFE-7100) and perfluorohexane (98 %, FC-72) were obtained from 3M (St. Paul, MN, USA). Perfluoro(methylcyclohexane) (94 %) was obtained from Alfa Aesar, Heysham, England. The purity of chemicals was checked by gas chromatograph, and all chemicals were used without further purification. The ternary mixture samples were weighed on a Mettler AB304S balance with the estimated uncertainty of
