A study of 2-heptanone and 2-octanone as solvents for two-phase electrochemistry .2. Facilitated ion transfers

Transition metal ion (Cd2+, Co2+, Cu2+, Mn2+, Ni2+, Zn2+) transfer from water to methyl n-amyl ketone (2-heptanone) and methyl n-hexyl ketone (2-octanone) facilitated by nitrogen-containing ligands has been investigated by a.c. and d.c. voltammetry. For Cd2+ Cu2+ and Zn2+ in the presence of terpyridine as a ligand both facilitated and complex ion transfers are observed, while for the Co2+- and Ni2+-terpyridine systems only complex ion transfer takes place. The differences between the facilitated and complex ion transfers have been discussed in terms of the different mechanisms of the transfer reactions. This study shows that it is possible to use 2-heptanone and 2-octanone in electro-assisted solvent extraction and supported liquid membrane separation of metal ions, based on two-phase electrochemical principles. (C) 1997 Elsevier Science S.A.