The solubilization of an aliphatic hydroxyoxime by dinonylnaphthalene sulfonic acid reversed micelles

Vapor pressure osmometry (VPO) was used to investigate the aggregation behavior of dinonylnaphthalene sulfonic acid (HDNNS), 5,8-diethyl-7-hydroxy-6-dodecanone oxime (HL, the active reagent in the commercial metal extractant LIX63), and their mixtures in hexane at 37°C. The results indicate that HDNNS is present as a heptamer in the concentration range of 1.0×10^-3-1.5×10^-1 mol dm^-3. In the case of the hydroxyoxime, the aggregation yields a mixture of monomers, dimers and trimers for the reagent range of 1.25×10^-3-1.0×10^-1 mol dm^-3. In a hexane solution containing 1.O×10^-2 mol dm^-3 HL and variable concentrations of HDNNS, the VPO data suggest that HDNNS reversed micelles solubilize the hydroxyoxime to give mixed reversed micelles, which may be represented as (HDNNS)₇·sHL, where 7 ≥ s ≥ 0.6 for 2×10^-3 mol dm^-3 ≤ [HDNNS]_T ≤ 1.5×10^-1 mol dm^-3.