Über das Phasenverhalten ternärer Systeme des Typs H2O-Öl-Nichtionisches Tensid

This paper deals with the change of the phase diagram of ternary systems of the type H₂O-oil-nonionic surfactant with temperature, in particular, with the question regarding the reasons for the separation of such mixtures into three phases. It is shown that the phase behavior is mainly determined by the interplay between the lower miscibility gap between oil and surfactant with the upper miscibility gap between H₂O and surfactant. From systematic investigations with dodecane, octane, cyclohexane and toluene as oils with ?simple“ alkylpolyethyleneglycolethers C_iE_j as surfactants, ten qualitative rules are derived concerning the dependence of the position and the width of the three-phase temperature interval on the hydrophobicity of the oil and the amphiphilicity of the surfactant. The rules permit the choice of the appropriate surfactant for application in chemical engineering. Finally, the phase behavior with mixtures of oils and mixtures of surfactants, resp., is studied.