Phase Behavior of 2-Butoxyethanols/Water/Oil Systems

Phase diagrams of 2-isobutoxyethanol (D)/water (W)/decane (O) system were studied at 2.0, 8.2, 15.0, 19.0, and 19.8 °C. The addition of O lowers the critical solution temperature of the D–W system from 26.2 to 2.0 °C, at which temperature the critical solution curve ends with the lower critical end point (Kc). On the other hand, the addition of W raises the critical solution temperature of the O–D system to 19.8 °C at which the critical solution curve ends with another critical end point (Lc). A three-phase region consisting of O, D, and W phases appears in a temperature range between the two critical end temperatures.