2000 Volume 26 Issue 4 Pages 511-516
Using three kinds of novel β-diketone of different alkyl-chain length (1-phenyl-1, 3-octanedione, 1-phenyl-1, 3-tetradecanedione and 1-phenyl-1, 3-icosanedione) and four kinds of neutral phosphorus compounds of different alkyl-chain length (tri-n-butylphosphine oxide, tri-n-octylphosphine oxide), tri -n-butyl phosp ate and tris (2-ethylhexyl) phosphate, the extraction equilibrium of lithium was investigated, and the synergistic effect of these extraction systems was examined, in order to determine the optimum extraction system for lithium.
It is found that lithium is synergistically extracted by the mixture of β-diketone and neutral phosphorus compounds, and that the ability of lithium extraction with the synergistic reagent of trialkylphosphine oxide is higher than that with tri-alkylphosphate. However, the effect of alkyl-chain length of β-diketone on the extraction equilibrium constants is negligibly small. These results are confirmed by molecular modeling of the extractants and synergistic reagents.