Surfactants are widely used for academic and industrial purposes. For this reason, thermodynamic and physical properties of surfactant and cosurfactant mixtures can provide important information about the nature of the molecular interactions present. In this work, volumetric and transport data of surfactant binary mixtures of the ethanol + Igepal series (Igepal CO-520, Igepal CO-630, Igepal CO-720, and Igepal CA-720) were determined experimentally within a range of temperature of T = 293.15− 323.15 K, at atmospheric pressure. From these data, the following derivative properties have been calculated: the excess molar volume, viscosity deviation, and coefficient of thermal expansion. All of these mixtures showed that attractive intermolecular forces are dominant.

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Azeotropic mixtures can occur in alcohol and alkane systems because of their close boiling points and highly nonideal molecular force interactions, leading to vapor–liquid coexistence envelopes with a maximum pressure. For this reason, it could be interesting from an academic and industrial viewpoint to find the appropriate solvents for separation processes involving azeotropic mixtures. Protic ionic liquids (PILs) are presented as an interesting alternative. This work reports liquid–liquid equilibrium data for ternary systems of alkanes (n-pentane, n-hexane, n-heptane, or n-octane) + alcohol (methanol or ethanol) + PIL 2-hydroxyethanolamine formate (2-HEAF) at 298.15 K and atmospheric pressure (101.3 kPa). Distribution coefficient (D) and selectivity parameter (S) data were used to evaluate the extracting potential of ionic liquids in separating alcohol from alkanes. Tie-line data were correlated with the nonrandom two liquid (NRTL) activity coefficient model, presenting a mean global deviation error of 0.9818%.

Surfactants are widely used in industrial applications associated with several solvents. Therefore, it is worthy to know the nature of the molecular interactions present in surfactants and cosurfactant mixtures, whose thermodynamic and physical properties can provide important information from an academic and industrial viewpoint. In this work, density and viscosity data of binary mixtures of toluene + Igepal series (Igepal CO-520, Igepal CO-630, Igepal CO-720, or Igepal CA-720) were experimentally determined within a range of temperature T = 293.15–333.15 K and at an atmospheric pressure of 101.325 kPa. From these data, the following derivative properties have been evaluated: excess molar volume, viscosity deviation, thermal expansion coefficient, partial molar volume, and excess thermal expansion coefficient. It was observed that all these mixtures showed the prevalence of dispersion intermolecular forces.

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