ROLE OF ADDUCTS IN THE SOLVENT EXTRACTION OF METAL CHELATES

The number of water molecules and organic solvent adducts associated with extracted metal chelates in both aqueous and nonaqueous phases have been determined for several systems: 8-hydroxyquinoline, acetylacetone, benzohydroxamic acid, diethyldithiocarbamates, and dithizone. The central metal ions were UO(,2)('2+), VO(,2)H('2), Fe('3+), Cu('2+) and Mn('2+), with chloroform, nitrobenzene, benzene, carbon tetrachloride, 1-butanol, 1-hexanol, nitromethane and 1-octanol as organic phases.;%E = 0.16V - 86.7;In those systems where complete data was obtainable, it was found that the total number of adducts and the ratio of water to organic adducts changed during the extraction process. Correlations were made between the ionic charge to chelate volume ratio and the adducts number. Measurements were made on the number of adducts as a function of pH and extraction correlations made.;Attempts have also been made to study the interactions of the organic adducts with the chelates before extraction takes place by the vapor pressure technique.;The following empirical correlation, where E is the percent of the chelate extracted and V is the hydrodynamic volume, was found to be valid for the vanadium(V) benzohydroxamic acid system in all of the solvents tested.