Synergistic effects of organophosphorus compounds on the extraction of copper from aqueous nitrate medium with N-(thioacetyl)benzamide into toluene

Department of Chemistry, The University of Burdwan, Burdwan-713 104, West Bengal, India
E-mail : basu_sukalyan@yahoo.co.in
Manuscript received 23 September 2010, revised 09 March 2011, accepted 23 March 2011

The extraction behaviour of CuII from an aqueous nitrate medium employing (N-thioacetyl) benzamide (HL) in toluene has been investigated In presence of several organophosphorus donors like, tri-octyl phosphine oxide (TOPO), tri-butyl phosphine oxide (TBPO) and tri-phenyl phosphine oxide (TPPO) at pH 5.0. The synergism was found in presence of neutral donors due to the formation of the adduct [Cu(L)₂.(S)] in toluene (S denotes neutral donor). The overall equilibrium constant for each of the three ternary complexes and also for binary system were calculated from extraction data. It Is found that the extent of extraction of Cu^ll In organic: phase both as the binary complex as well as ternary complex Increase with increase in temperature. The temperature dependence of the equilibrium constants were Investigated In order to evaluate the thermodynamic: parameters like enthalpy (ΔH⁰), entropy (ΔS⁰ ) and free energy (ΔG⁰). Extraction mechanism was supported by IR spectra of ternary adduct.