MOLECULAR DYNAMICS SIMULATION OF INTERFACIAL ADSORPTION OF 2-HYDROXY OXIME AT HEPTANE/WATER INTERFACE

Interfacial adsorptivities of three 2-hydroxy oximes with nonyl group in heptane/water system were simulated by means of the molecular mechanics (MM) and molecular dynamics (MD) calculations. The simulations demonstrated that a 2-hydroxy oxime molecule was fluctuating between the interface and the heptane phase, and the adsorbed molecule at the interface had an oriented configuration in which the hydroxy oxime group, which can coordinate to a metal ion, was in the aqueous phase and the hydrophobic nonyl group was in the organic phase. These results gave an insight into the explanation of the experimental results that the complexation rate constants of the adsorbed ligand with Ni(ll) ion were comparable with those in the bulk aqueous phase. The adsorption energies of the extractants were estimated from the difference between the solvation energies at the interface and in the organic phase.