Zusammenfassung
In this study, liq.-liq. equil. measurements were performed for different ternary, water (or brine)/decane or dodecane/mono-propylene glycol ether (C3P1) or di-propylene glycol ether (C3P2) systems in order to build the so-called fish phase diagrams (temp. as a function of surfactant for a given polar-apolar solvent mixt.) and to compare them to the well-known water (or brine)/decane or ...
Zusammenfassung
In this study, liq.-liq. equil. measurements were performed for different ternary, water (or brine)/decane or dodecane/mono-propylene glycol ether (C3P1) or di-propylene glycol ether (C3P2) systems in order to build the so-called fish phase diagrams (temp. as a function of surfactant for a given polar-apolar solvent mixt.) and to compare them to the well-known water (or brine)/decane or dodecane/ethylene glycol mono-Bu ether (C4E1) phase diagrams. The study is motivated by the lower toxicity of the CxPy compared to the corresponding CxEy. Toxicity is of particular importance for any use of such mols. in the environment. Like in the presence of C4E1, the formation of Winsor type I → III → II phase transitions with increasing temp. was obsd. for the CxPy systems. The LCST (Lower Crit. Soln. Temp.) and UCST (Upper Crit. Soln. Temp.) of the newly studied systems were detd. The values of the γ0 parameter (in mole fraction), the min. value of surfactant needed to form Winsor III, increased in comparison to the C4E1 systems. The value of ~γ (in mole fraction), min. value of surfactant needed to reach Winsor IV from Winsor III, was comparable using C4E1 and C3P1, and lower in the presence of C3P2. The substitution of decane by dodecane led to a stronger water affinity of C4E1 and C3P2 as greater values of the LCST and UCST have been obsd. in the presence of dodecane. By contrast, a lower hydration of C4E1 and C3P1 was found when increasing the NaCl content in brine. It can be concluded that less toxic C3P1 and C3P2 can be envisaged as a substitute of the contested C4E1 to formulate microemulsions and particularly Winsor III systems.