For a fundamental study on the development of novel extraction divalent metal, the extraction behaviour of copper(II), cobalt(II) and nickel(II) is studied with salicylideneaniline (SAN). The phenol group in the Schiff base moiety leads to a large increase in the percentage of transition metal ions. SAN has both good reactivity towards metal ions and solubility in organic solvents. The solvent extraction of copper(II), cobalt(II) and nickel(II) with salicylideneaniline from sulphate media is studied with the following parameters: pH, concentration of the extractant and the nature of diluent. The stoichiometry coefficients of the extracted species are determined by the slope analysis method. The extraction reaction proceeds by cation exchange mechanism and the extracted species are: CuL2HL, CoL2HL and NiL2. The extaction constants are evaluated for the different diluents. Under suitable conditions of pH, the solvent extraction of cobalt(II) and nickel(II) in different diluents leads to third phase formatio...

Liquid–liquid extraction of Cu(II), Co(II) and Ni(II) with salicylidèneaniline from sulphate media

This paper highlights the results of investigations carried out on the extraction of lanthanoids such as Nd(III), Eu(III) and Tm(III) from nitrate solutions into chloroform with 3-phenyl-4-(4-fluorobenzoyl)-5-isoxazolone (HFBPI) in the presence and absence of various crown ethers (CE): 18-crown-6 (18C6), dicyclohexano-18-crown-6 (DC18C6), benzo-18-crown-6 (B18C6) and dibenzo-18-crown-6 (DB18C6). The results demonstrated that these trivalent metal ions were extracted into chloroform as Ln(FBPI) 3 with HFBPI alone and as Ln(FBPI) 3 .CE in the presence of a CE. The equilibrium constants of the above extracted complexes deduced by a non-linear regression analysis were found to increase monotonically with a decrease in ionic radii of these metal ions. The addition of a CE to the metal chelate system significantly improves the extraction efficiency of these metal ions. The complexation strength of trivalent lanthanoids with various CEs follows the order: DC18C6 > 18C6 > B18C6 > DB18C6. Solid complexes of Eu(III) with HFBPI alone and with mixtures of HFBPI and various crown ethers have been isolated and characterised by IR and 1 H NMR spectral data to further clarify the nature of the extracted complexes.

Crown ethers as synergists in the extraction of trivalent lanthanoids with 3-phenyl-4-(4-fluorobenzoyl)-5-isoxazolone

Synergistic solvent extraction of trivalent lanthanides such as Nd, Eu and Tm has been studied using mixtures of 3-phenyl-4-benzoyl-5-isoxazolone (HPBI) and 18-crown-6; 15-crown-5, benzo-15-crown-5, or dibenzo-18-crown-6. The results demonstrate that these trivalent metal ions are extracted into chloroform as Ln(PBI)3 with HPBI alone and as Ln(PBI) 3. CE in the presence of crown ethers (CE). The equilibrium constants of the above species are found to increase monotonically with the decreasing ionic radii of these trivalent lanthanides. The addition of a crown ether to the metal chelate system significantly enhances the extractability of these trivalent metal ions.

Synergistic solvent extraction of trivalent lanthanides with mixtures of 3-phenyl-4-benzoyl-5-isoxazolone and crown ethers

Steric effects of polymethylene chain of 4-acylbis(pyrazolones) on the solvent extraction of trivalent lanthanoids: synergistic effect with mono and bifunctional neutral organophosphorus extractants

The synergistic solvent extraction of Pr,Gd and Yb with mixtures of 1-phenyl-3-methyl-4-benzoyl-pyrazol-5-one(HP) and a crovm ether benzo-15-crown-5(B15C5 or S) in CCl4,C6H6 and CHC13 has been studied.The composition of the extracted species has been determined as LnP,,nS where LnP3 nS where Lv =Pr, Gd and Yb and n=1 or 2.Mixed complexes LnP3.S have been found when C6H6 and CHC13 were used as diluents and both LnP3.S and LnP3.2S - when CC14 was used.The influence of the diluents on the extraction process has been discussed.

Synergistic extraction of lanthanides with mixtures of 1-phen1l-3-methyl-4-benzoyl-pyrazol-5-one and eenzo-15- crown-5

Solvent extraction studies have been carried out on aqueous complexes of La(Ill), Eu(III) and Lu(III) with macrocyclic ligands DAPDA (1,7-diaza-4,10,13-tri-oxacyclopentadecane-N,N’-diacetic acid) and DACDA (1, 10-diaza-4,7,13,16-tetraoxacyclooctadecane-N,N’-diacetic acid) using TTA (thenoyltrifluoroacetone) as the extractant in chloroform and nitrobenzene. EDDA (ethylenediamine-N,N’-diacetic acid), a non-cyclic polyaminopolycarboxylic acid, was also included for comparison purposes These results, along with our earlier work in benzene medium, have been used to elucidate the nature of extracted species. It appears that nitrobenzene, a diluent of high dielectric constant, favors the extraction of ion pairs instead of the mixed complexes observed earlier using the relatively inert diluent, benzene.

V. K. Manchanda

Papers

The effect of the diluent on the extraction of lanthanide complexes of macrocyclic ionophores