Prediction of pKa Values of Extractant Using Novel Quantitative Structure–Property Relationship Models

The dissociation equilibrium constant (p K a ) of an extractant is one of the main factors determining the reactive extraction behavior. A quantitative structure–property relationship (QSPR) was investigated for predicting the p K a of some pure extractants and the apparent basicity (p K a,B ) of three typical mixture solvents, trioctylamine (TOA)/hexane, TOA/1-octanol, and TOA/methyl isobutyl ketone (MIBK). Novel QSPR models for the p K a of a pure extractant and the p K a,B of a mixture solvent were set up. The novel QSPR models include the concentration of extractant in the solvent and three kinds of molecular connectivity indices of extractant and diluent. The calculated values from the models of the pure extractant and mixture solvents show good consistency with experimental values.