Dielectric constants of binary mixtures of MIBK, an extractant used in nuclear energy industry, with six apolar solvents i.e. benzene, dioxane, cyclohexane, carbon tetrachloride, p-xylene and n-heptane have been measured at 455 kHz. The data are used to evaluate the Eyring's structural parameter, G*, in these systems to assess the nature of non-specific solute-solvent interaction. The value of G* is found to be influenced by the nature of the solvent.