T. V. Healy
Aug 1, 1963
Citations
0
Influential Citations
48
Citations
Journal
Nuclear Science and Engineering
Abstract
Thenoyl trifluoroacetone (HTTA) was used as the acid in combination with neutral organophosphates (S) to demonstrate a strong (synergistic) enhancement of extraction of metaliic species. This enhancement using HTTA is exhibited by many metal species and is much larger (up to 10/sup 8/) than that obtained with the dialkyl phosphoric acids (up to 10/sup 2/). This effect is increased as S is changed from the neutral alkyl phosphates, through phosphonates, to the phosphine oxides. Examples of synergism with HTTA and S are also given where S, the neutral additive, contains no phosphorus and is an amide, alcohol, or ketone. Tracer work has established the composition of over 30 extracting species containing di, tri, and tetravalent metals of the general formula M(TTA) S where x is the valency of M, and y varies between 1 and 3. Confirmation of these formulas was, in a number of instances, obtained by ultraviolet spectrophotometry on tenth molar solutions and by analysis of anhydrous microcrystalline solids isolated from solution. Stability constants were also ascertained for many of these synergistic species. Infrared work indicates the likelihood of some of the chelate ligands becoming monodentate in the synergistic species with direct bonding of S to the metal.more » If an excess of neutral ester S is added to a synergistic system, antisynergism, that is the reverse of synergism, occurs and decreases of 10/sup 8/ in extraction coefficient can occur. The degree of antisynergism depends on the quantity and nature of S. S could be an alcohol, amide, ketone, ether, ester (including organophosphorus esters) or, in fact, a so called inert diluent such as benzene or chloroform. The cause of these very large antisynergistic effects is bound up with the water content of the neutral additive S and of the diluent. There is ultraviolet spectral evidence that the anhydrous species is destroyed with formation of a hydrated TTA species. (auth)« less