Radiotracer Study of the Effects of Organophosphorus Donors on the Extraction of Iron(III) with 2-Hydroxy-N-phenylbenzamide in n-Butanol

摘要

The behavior of Fe(III) in extraction from an aqueous chloride medium with 2-hydroxy-N-phenylbenzamide (HA) in n-butanol in the presence of several organophosphorus donors like trioctyl-phosphine oxide, triphenylphosphine oxide, and tributyl phosphate at pH 2.0 was studied using radiotracer technique. The overall equilibrium constants for each of the three ternary extraction systems and for the binary extraction system were calculated. The temperature dependences of the equilibrium constants were examined to evaluate the thermodynamic functions like enthalpy ((DELTA)H~(0)), entropy ((DELTA)S~(0)), and free energy ((DELTA)G~(0)). It was found that the extent of Fe(III) extraction into the organic phase both as the binary complex [FeA_(2)Cl(H_(2)O)] and as the ternary complex [FeA_(2)Cl(S)] increases with temperature.