ETHANE-1,2-DIOL WATER SOLVENT SYSTEM - RELATIVE PERMITTIVITY AS A FUNCTION OF TEMPERATURE AND BINARY COMPOSITION

Relative permittivity (epsilon) data for several aqueous binary mixtures of ethane-1,2-diol at various temperatures in the range -10 to + 80-degrees-C are presented. The experimental data were processed by empirical relations stating the dependence of epsilon on temperature and binary composition expressed as mole fraction of ethane-1,2-diol. The variation of epsilon with mole fraction is non-linear at the temperatures investigated. Ethane-1,2-diol behaves as a structure breaker, showing negative deviations in epsilon vs. composition curves. Minima occur in the excess function (epsilon(E)), and the magnitude of the deviations with respect to pure species seems to be influenced by the dipolarity, polarizability and any hydrogen-bonding tendency of the two cosolvents. These empirical patterns in dielectric behaviour were very useful in order to establish the stoichiometric ratio of the ethane-1,2-diol-water solvent-cosolvent adduct which is probably formed in solution.