Solvent extraction of alkylphosphoric acid derivatives between water and immiscible organic solvents

The distribution constants of di-n-octyl, di(2-ethylhexyl), dibenzyl, di-n-hexyl and di-n-butylphosphoric acids between water and a variety of organic solvents, as well as the dimerization constants in the organic phase, have been correlated with the solvatochromic parameters of the solvent. The dimerization of the phosphoric acid derivatives in the organic phase is taken into account and the global process, that is to say extraction and dimerization, is included in the Leggett equation. The proposed equations can be used to select the more appropriate diluent to extract several metal ions from aqueous solutions using the mentioned phosphoric acids.