Ternary Liquid – Liquid Equilibria: Hexamethyldisiloxane – Dimethyl Sulfoxide – Methyl Ethyl Ketone (-Diethyl Ketone)

New experimental solubilities and tie line data for ternary mixtures containing two completely miscible binaries and one nonmiscible binary as part of a program to determine the thermodynamic properties of a series of ternary and binary systems with HMDS [1–3] are given. Hexamethyldisiloxane 99.5%, NMR grade, 2-butanone 99.5%, HPLC grade (MEK), 3-pentanone 99% (DEK) and dimethyl sulfoxide 99.9%, HPLC grade were purchased from Sigma-Aldrich and used without further purification. The refraction indices were measured with refractometer R-L3 and agreed well with data published in literature [4]. The binodal curve of the ternary systems was determined by Bancroft’s method [5]. The HMDS – ketone ratios used for preparation of solutions, as well as a limiting amount of DMSO soluble in the individual ternary systems at 293.15 and 303.15 ± 0.03 K, are listed in Table 1. The experimental errors were within 0.01 weight %. The concentration of components in conjugate phases determined by graphoanalytical method has been described in [5,6]. This method is based on characteristic properties of the tie lines. The tie line is located in heterogeneous surface area and terminates in points on the binodal curve [7].