DIELECTRIC BEHAVIOR OF THE THYLFORMAMIDE-2-METHOXYETHANOL-1,2-DIMETHOXYETHANE TERNARY SOLVENT SYSTEM FROM -10-DEGREES-C TO -DEGREES-C(20)

The static relative permittivities, epsilon, and excess properties, ep silon(E), of the ternary mixtures N,N-dimethylformamide (DMF)-2-methox yethanol (ME)-1,2-dimethoxyethane (DME) have been measured at several temperatures in the range -10 to +20-degrees-C. This ternary system sh ows interesting properties for use as a mixed solvent and for electroa nalytical applications. The study of these mixtures should help to inc rease our understanding of the co-solvation of ionizable and inert sol utes. The behaviour of epsilon(E) is quite interesting because this qu antity assumes partly positive and partly negative values in the compo sition domain. As a consequence, there are mixtures which have epsilon (E) = 0, indicating ideal dielectric mixing behaviour. The excess prop erty is discussed in terms of the influence of specific interactions b etween components, the order and degree of packing in the mixtures and any other effects which produce long-range structure in these mixed l iquids.