Synergistic systems solvent extraction

The new features are detailed in this review most using diamide as a model system and illustrated with published data on other extractant systems. Figure 7.1 summarizes the structure of the different extractants cited in this chapter. The mixture of extractants as synergistic systems and extractants, such as the N-polydentate ligands BTP (39, 40), BTBP (41, 42), or bis-malonamide (43), will not be treated here. These extractants have low solubility in alkane and are generally used in chlorinated solvent or octanol or diamide/alkane solution to enhance their solubility. 

Preston, J. S. du Preez, A. C. Solvent extraction of nickel from acidic solutions using synergistic mixtures containing pyridinecarboxylate esters. 3. Systems based on arylsulphonic acids. J. Chem. Technol. Biotechnol. 1998, 71, 43-50. 

These equations do not provide complete definition of the reactions that may be of significance in particular solvent extraction systems. For example, HTTA can exist as a keto, an enol, and a keto-hydrate species. The metal combines with the enol form, which usually is the dominant one in organic solvents (e.g., K = [HTTA]en i/[HTTA]]jet = 6 in wet benzene). The kinetics of the keto -> enol reaction are not fast although it seems to be catalyzed by the presence of a reagent such as TBP or TOPO. Such reagents react with the enol form in drier solvents but cannot compete with water in wetter ones. HTTA TBP and TBP H2O species also are present in these synergistic systems. However, if extraction into only one solvent (e.g., benzene) is considered, these effects are constant and need not be considered in a simple analysis. 

Watanabe, M., Mirvaliev, R., Tachimori, S. et al. 2004. Selective extraction of americium(III) over macroscopic concentration of lanthanides(III) by synergistic system of TPEN and D2EHPA in 1-octanol. Solvent Extr. Ion Exch. 22 (3) 377-390. 

Cordier, P.Y., Francois, N., Boubals, N., Madic, C., Hudson, M.J., Liljenzin, J.O. 1999. Synergistic systems for the selective extraction of trivalent actinides from mixtures of trivalent actinides and lanthanides. ISEC 99 Conference on Solvent Extraction for the 21st Century, July, Barcelona, Spain. 

Andersson, S., Ekberg, C., Foreman, M.R.S., Hudson, M.J., Liljenzin, J.O., Nilsson, M., Skamemark, G., Saphiu, K. 2003. Extraction behavior of the synergistic system 2,6-bis-(benzoxazolyl)-4-dodecyloxylpyridine and 2-bromodecanoic acid using Am and Eu as radioactive tracers. Solvent Extraction and Ion Exchange 21(5) 621-636. 

Bond, A. H., Dietz, M. L., and Chiarizia, R. (2000) Incorporating Size Selectivity into Synergistic Solvent Extraction A Review of Crown Ether-Containing Systems, Ind. Eng. Chem. Res., 39(10), 3442-3464. 

Yang ZF, Guha AK, and Sirkar KK. Simultaneous and synergistic extraction of cationic and anionic heavy metaUic species by a mixed solvent extraction system and a novel contained hquid membrane device. Indust Eng Chem Res, 1996 35(11) 4214-4220. 

Synergistic mixtures. A solvent extraction system is said to be synergistic when the distribution coefficient obtained frcm a mixture of extractants is greater than the sum of distribution coefficients of each extractant alone. Such systems are usually... 

As explained above, in this section, we review results concerning extraction systems in which the molecular solvent has been replaced by an IL phase, using a molecular well-known ligand for the extraction, and we include synergistic systems of the form M /HX/ZOL+LO/DL. 

C. Y. Cheng, Solvent extraction of nickel and cobalt with synergistic systems consisting of carboxylic acid and aliphatic hydroxy oxime . Hydrometallurgy, 84 (2006), 109-117. 

Barnard, K.R. and Turner, N.L. (2011) The effect of temperature on hydroxyoxime stability in the LIX 63 - Versatic 10 - tributyl phosphate synergistic solvent extraction system under synthetic nickel laterite conditions Hydrometallurgy 109 245-251... 

The solvent extraction reaction chemistry in specific medium, extractants, pH, diluents, and in synergistic systems are discussed in relation to the transfer of the rare earth extractable complex from the aqueous phase to the organic phase. 

C.E Baes, Jr, W.J. McDotvell, S.A. Bryan, The Interpretation of Equilibriunz Data from Synergistic Solvent Extraction systems, Soh. Extr. Ion Exch., 5, 1—28 (1987). 

Extraction behaviour of the synergistic system 2,6-bis-(benzoxazolyl)-4-dodecyloxylpyridine and 2-bromodecanoic acid using Am and Eu as radioactive tracers. Solvent Extr. Ion Exch., 21, 621 -636. 

In the simplest cases, the solvent may consist of one specified component, although in fact in a steady-state cyclic process it is highly unlikely that the solvent will ever come back to the initial composition at time zero. Rather, perhaps, one can say that make-up will entail addition of one material only. Again, clearly this need not be a pure compound, but its composition should be consistent. The single solvent offers limited scope for manipulating the system since it alone must meet all process and operational requirements. In other words, it must satisfy all aspects that will lead to an overall viable system. These aspects include selectivity, capacity, solubility, mass transfer, phase separation, costs, among others. The solvent is, therefore, a mixture components. The solvent components are extractant, (ii) diluent, (iii) modifier, and (iv) synergist. 

Moyer, B.A., McDowell, W.J., Ontko, R.J., Bryan, S.A., Case, G.N. Complexation of strontium in the synergistic extraction system dicyclohexano-18-crown-6, versatic acid, carbon tetrachloride. Solvent Extr. Ion Exch. (1986), 4(1), 83-93. 

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