Ethane-1,2-diol–water solvent system: relative permittivity as a function of temperature and binary composition

Abstract

Relative permittivity (ε) data for several aqueous binary mixtures of ethane-1,2-diol at various temperatures in the range –10 to +80 °C are presented. The experimental data were processed by empirical relations stating the dependence of ε on temperature and binary composition expressed as mole fraction of ethane-1,2-diol. The variation of ε with mole fraction is non-linear at the temperatures investigated. Ethane-1,2-diol behaves as a structure breaker, showing negative deviations in ε vs. composition curves.

Minima occur in the excess function (ε^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.