Interfacial tensions of two-phase ternary systems

Sada, Eizô; Kito, Shigeharu; Yamashita, Mineo

doi:10.1021/je60067a026

Cited by 20 publications

(19 citation statements)

References 6 publications

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“…The phase diagrams of the ternary systems alcohol-waterbenzene were determined at 25°C with this technique (Lara et al, 1981b) and agree to within experimental error with those of Sada et al (1975), Ross and Patterson (1979) and Hermann et al (1978).…”

Section: Methodssupporting

confidence: 75%

Tar sand extractions with microemulsions: I‐the dissolution of light hydrocarbons by microemulsions using 2‐butoxyethanol and diethylmethylamine as cosurfactants

et al. 1983

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For oil sand extractions with microemulsions it is important to disperse large quantities of light hydrocarbons in an aqueous medium. Fundamental studies on the properties of 2‐butoxyethanol (BE) and diethylmethylamine (Et2McN) in water suggest that these two liquids could be more effective cosurfactants than the usual alcohols used for this purpose. The phase diagrams of microemulsions using BE and Et2MeN as cosurfactants, combined with typical ionic and non‐ionic surfactants and typical aliphatic and aromatic hydrocarbons, were therefore investigated and compared with microemulsions based on n‐butanol. Although the phase diagrams depend significantly on the nature of the surfactant and of the oil, the monophasic region generally increases with the cosurfactant in the order n‐butanol < Et2McN < BE. With the active mixture BE‐cetyltrimethylammonium bromide, temperature has little effect on the phase diagram and NaCl generally destabilizes the microemulsion.

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Section: Methodssupporting

confidence: 75%

Tar sand extractions with microemulsions: I‐the dissolution of light hydrocarbons by microemulsions using 2‐butoxyethanol and diethylmethylamine as cosurfactants

et al. 1983

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“…To conclude our study, we compared the behavior of our ternary system with other water–oil mixtures for which data are available in the literature. − TBA exhibits similar behavior regardless of the “oil” in the mixture (Figure A). Comparing our results with ternary systems of different hydrophobes as well as a different hydrotrope (isopropanol) shows the same trend.…”

Section: Resultsmentioning

confidence: 99%

Dual Action of Hydrotropes at the Water/Oil Interface

et al. 2017

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Hydrotropes are substances containing small amphiphilic molecules, which increase solubility of nonpolar (hydrophobic) substances in water. Hydrotropes may form dynamic clusters (less or about 1 ns lifetime) with water molecules; such clusters can be viewed as “pre-micelles” or as “micellar-like” structural fluctuations. We present the results of experimental and molecular dynamics (MD) simulation studies of interfacial phenomena and liquid–liquid equilibrium in the mixtures of water and cyclohexane with the addition of a typical nonionic hydrotrope, tertiary butanol. The interfacial tension between the aqueous and oil phases was measured by Wilhelmy plate and spinning drop methods with overlapping conditions in excellent agreement between techniques. The correlation length of the concentration fluctuations, which is proportional to the thickness of the interface near the liquid–liquid critical point, was measured by dynamic light scattering. In addition, we studied the interfacial tension and water–oil interfacial profiles by MD simulations of a model representing this ternary system. Both experimental and simulation studies consistently demonstrate a spectacular crossover between two limits in the behavior of the water–oil interfacial properties upon addition of the hydrotrope: at low concentrations the hydrotrope acts as a surfactant, decreasing the interfacial tension by adsorption of hydrotrope molecules on the interface, while at higher concentrations it acts as a cosolvent with the interfacial tension vanishing in accordance with a scaling power-law upon approach to the liquid–liquid critical point. It is found that the relation between the thickness of the interface and the interfacial tension follows a scaling law in the entire range of interfacial tensions, from a “sharp” interface in the absence of the hydrotrope to a “smooth” interface near the critical point. We also demonstrate the generic nature of the dual behavior of hydrotropes by comparing the studied ternary system with systems containing different hydrocarbons and hydrotropes.

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“…The overwhelming majority of the experimental data are obtained for a relatively narrow range of high values of interfacial tension (γ = 1–50 mN/m) that does not cover the near-critical region (γ < 0.1 mN/m). Notable exceptions here are refs, , in which the interfacial-tension data were obtained for ternary systems of water–ethanol–benzene, water–ethanol–hexane in a broader range of hydrotrope concentrations, and, especially, ref for water– tert -butanol–CHX, in which a dual action of TBA at the water–oil interface, resulting in crossover behavior of the interfacial tension, was demonstrated for the first time.…”

Section: Introductionmentioning

confidence: 88%

“…Hydrotropes in water–oil systems decrease the interfacial tension because of their adsorption at the interface between the two liquid phases. Experimental data on liquid–liquid interfacial tension in ternary systems with various hydrotropes are presented in many works. ,− Experimental data on interfacial tension are available for ternary systems in which hydrotropes are alcohols (methanol, ethanol, n -propanol, i -propanol, n -butanol, tert -butanol), ketones (acetone, methyl ethyl ketone), carboxylic acids (acetic acid, propionic acid). The overwhelming majority of the experimental data are obtained for a relatively narrow range of high values of interfacial tension (γ = 1–50 mN/m) that does not cover the near-critical region (γ < 0.1 mN/m).…”

Section: Introductionmentioning

confidence: 99%

Generic Nature of Interfacial Phenomena in Solutions of Nonionic Hydrotropes

et al. 2019

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Nonionic hydrotropes (low-molecular-weight amphiphiles) demonstrate striking dual actions in bulk solutions and interfaces, exhibiting both surfactant-like and co-solvent properties. We report on peculiar, strongly affected by this duality, liquid–liquid and air–liquid–liquid interfacial behavior in aqueous ternary systems, containing hydrotropes and hydrocarbons, in a broad range of compositions and at various temperatures. Phase diagrams of the studied systems, containing tertiary butanol (TBA), as a hydrotrope, are of Type 1: the hydrotrope, at the experimental conditions, is completely miscible with water and with all investigated hydrocarbons [cyclohexane (CHX), toluene (TOL), and n-decane (DEC)], whereas the ternary mixtures exhibit liquid–liquid phase separation terminated at corresponding critical points. The shape and location of the phase separation boundary are only weakly dependent on temperature and the hydrocarbon’s nature; however, the critical point in the water–TBA–DEC system is significantly shifted toward a higher TBA concentration. For the experimentally studied systems and for available data reported in the literature, we confirmed an apparently generic (for nonionic hydrotropes) phenomenon of a dual action at water–oil interfaces (earlier found in water–TBA–CHX [J. Phys. Chem. C 2017, 121, 16423]): at low concentrations, hydrotropes saturate the water–oil interface like a surfactant, whereas at higher concentrations they act as co-solvents, resulting in vanishing interfacial tension at the liquid–liquid critical point. We suggest a universal crossover function that accurately interpolates the two theoretically based limits of interfacial behavior. This crossover function also accounts for earlier deviations from Langmuir–von Szyszkowski limiting behavior in the water–TBA–DEC system, caused by lower solubility (relative to other studied hydrocarbons) of DEC in water. An intriguing correlation between the dual action of hydrotropes at the water–oil interface and the behavior of the liquid–air interfaces is also discussed.

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Interfacial tensions of two-phase ternary systems

Cited by 20 publications

References 6 publications

Tar sand extractions with microemulsions: I‐the dissolution of light hydrocarbons by microemulsions using 2‐butoxyethanol and diethylmethylamine as cosurfactants

Tar sand extractions with microemulsions: I‐the dissolution of light hydrocarbons by microemulsions using 2‐butoxyethanol and diethylmethylamine as cosurfactants

Dual Action of Hydrotropes at the Water/Oil Interface

Generic Nature of Interfacial Phenomena in Solutions of Nonionic Hydrotropes

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