Estimation of properties of dialkylorganophosphorus acidic extractants in two-phase liquid systems

The distribution, dimerization and dissociation constants of dialkylorganop hosphorus acidic extractants XYP(O)OH affecting their behaviour in the two- phase liquid systems involving 'dry' solvents have been correlated with the properties of solutes and solvents in accordance with the Kamlet and Taft and Leggett models. It has been demonstrated that dialkyl derivatives of ph osphoric, phosphonic and phosphinic acids could be regarded as members of t he same family of acidic extractants. As a result, the distribution, dimeri zation and dissociation constants as well as the products of these constant s can be estimated from the appropriate statistically valid correlations in volving the molar intrinsic volumes and Kabatchnik constants of considered acids and solvatochromic parameters pi*, alpha and beta of 'dry' solvents. Both compared models are adequate for the analysis and estimation of equili brium constants of dialkylorganosphosphorus acids; however, the Leggett mod el has been found as more convenient than the Kamlet and Taft model. (C) 20 00 Elsevier Science B.V. All rights reserved.