Comparison of Alkyl Phosphine Oxides in Polar and Non-Polar Diluents: Solvent Extraction, Spectroscopic, Conductivity and Theoretical Study

Trialkyl phosphine oxides (TOPO) are a common use class of extractants in hydrometallurgy. Organic diluent has a significant influence on the extraction properties of the system. In this work, we investigated the influence of two diluents – non-polar (octane) and with high polarity (<i>m</i>-nitrobenzotrifluoride (F-3)) on the extraction properties for a TOPO’s derivatives. It was shown that <i>f-</i>elements extraction in octane is higher than with F-3. The obtained experimental data were supported by quantum-chemical calculations to evaluate the thermodynamics of the extraction process. In addition, the differences of complex formation of extractants with <i>f</i>-elements were established using UV-visible spectrophotometry, NMR spectroscopy and electrical conductivity measurements of organic phases.