2006 Volume 7 Pages 1-9
Metal ion extractability in liquid-liquid extraction using spirobenzopyrans possessing a crown ether moiety was evaluated by molecular dynamics. It was found that a longer alkyl group attached to the spirobenzopyran ring results in greater stability in the organic phase. The same trend was observed for the model metal complex. When the crowned spirobenzopyran was complexed with an alkali metal ion, the steric energy in the aqueous phase was decreased. However, the energy was higher than that of the complex in the organic phase; as a result, the complex was more stable in the organic phase. In addition, the metal ion which forms the most stable complex depends on the ring size of the crown ether. The tendency was confirmed by the liquid-liquid extraction of alkali metal ion with the crowned spirobenzopyran. This indicates that it is possible to predict the properties of extraction reagents from their steric energy values calculated using molecular dynamics.
