DIELECTRIC-PROPERTIES OF METHANOL PLUS HEXANE CRITICAL MIXTURES WITHOUT AND WITH IONIC ADDITIVES

The electric permittivity and conductivity of methanol + hexane and me thanol + hexane + (CH3)(4)NCl mixtures were investigated in the vicini ty of consolute critical point. The properties of the investigated sys tem are similar to those of others phase separating mixtures. The obse rved low frequency dispersion was explained in terms of Maxwell-Wagner phenomena in a mixture with large concentration fluctuations. The gen eralised equations describing epsilon(t) and sigma(t) (epsilon is the electric permittivity, sigma -is the specific conductivity, t -is the reduced temperature) both in low and high frequencies were proposed an d tested for the title systems. Critical mixtures and microemulsions w ere found to be similar. The permittivity dispersion both for x < x(C) and x = x(C) is large (x is the mole fraction of methanol, x(C) is th e critical concentration) -as in ''water-in-oil'' emulsions, whereas i n the alcohol-rich systems, x > x(C), the dispersion is negligible -as in ''oil-in-water'' ones.