Studies on the effect of cholera substitution in the oxine molecule on the extraction of cadmium [II] into n-butanol

Extraction studies were undertaken with cadmium [II] in the presence of oxine and its chloro derivatives to derive information on the effect of substitution in the oxine molecule. Oxine, 5-chlorooxine and 5, 7-dichlorooxine form complexes with cadmium in the pH range7.9-8.4, 7 .8-8.2 and 7.0-7.6 respectively which was extract into n-butanol giving fairly intense yellow colour. The extracting species are found to be monomeric in cadmium in all the systems. pH dependence of log D plots revealed the release of two protons in the process of extraction. The optimum pH for extraction of cadmium chelates of 5-chlorooxine and 5, 7-dichlorooxine have drifted towards lower side when compared with that of cadmium. [Il]-oxine chelate. Bathochromic shifts were observed in the case of cadmium [II]-chlorooxine systems. The values of the conditional extraction constants suggest that the order of efficacy of extraction is as follows : Oxine < 5-chlorooxine < 5,7-dichlorooxine

Self adduct formation in the extraction of uranium [VI] chelate of 8-quinolinol

Tremendous amount of work has been done on the metal chelate system in which any one kind of ligand is involved in chelation. The effect of such factors as ligand basicities, sizes of chelate rings, steric factors and metal ion acidity have been evaluated in the formation of a chelate from the aquated metal ion and the chelating agent. The extraction of coordination - unsaturated chelates can, in some cases, be favoured by the use of an excess of chelating agent. Despite the contributions from several authors to the formation of uranium oxinate complexes, it is interesting that the composition and other characteristics of the extracting uranium-oxine system are not established with certainty. The present study attempts to throw more light on these aspects

Studies on the extraction of vanadium [V] -dihalooxinate complexes

The formation and extraction of vanadium [V]-5,7-dihalooxinate complexes were investigated. The optimum pH for the extraction of both the complexes was found to be 2.5 - 4.5. Polymerisation studies revealed that the complex contains monomeric vanadium. The extracting species is found to have vanadium: reagent: alcohol in the ratio 1:2:1. Thus the species was assumed to be an ester as VO [OR] L2 [L being the anion of reagent]. The conditional extraction constants were determined. The similarities and differences of these ligands in their behaviour of complex formation and extraction were discussed at the end