Effect of temperature on pseudoternary system Tween-80–butanol–hexane–water

Phase diagrams of pseudoternary systems of Tween-80, butanol, hexane and water were constructed by a visual titration method. The cloud points (CPs) at various compositions were determined and the variations in the cloud points were analyzed on the basis of changes in the composition of the different components in the microemulsions. A quantitative model was established by using multiple regression analysis considering weight percent of emulsifier (surfactant + cosurfactant) and oil as independent variables. A lowering in the CP with increase in emulsifier content and decrease in oil content was observed. Addition of sodium chloride also depressed the CP significantly. Further, with the increase in temperature the turbid phase started separating to three different transparent zones. The upper layer was recognized as the oil-rich phase, middle layer was due to microemulsion and the lower layer was found to be a micellar system. Metal ions and colored organic substrates partitioned into these different phases, which provides scope for applications in metal ion preconcentration.

With increase in temperature, pseudoternary mixtures of Tween-80, butanol, hexane and water are transformed into a turbid system, which separates into three different transparent phases.Figure optionsDownload high-quality image (107 K)Download as PowerPoint slideResearch highlights
► A large Winsor IV domain consisting of micelles, reversed micelles and microemulsions.
► Addition of sodium chloride leads to formation of liquid crystalline phase.
► A quantitative cloud point-composition relationship is established.
► On heating mass transfer in turbid system leads to appearance of three phases.
► Preconcentration of organic and inorganic solutes could be achieved.