Extraction behaviour

Thenoyltrifluoroacetone(TTA), C4H3S,CO,CH2,COCF3. This is a crystalline solid, m.p. 43 °C it is, of course, a /1-diketone, and the trifluoromethyl group increases the acidity of the enol form so that extractions at low pH values are feasible. The reactivity of TTA is similar to that of acetylacetone it is generally used as a 0.1-0.5 M solution in benzene or toluene. The difference in extraction behaviour of hafnium and zirconium, and also among lanthanides and actinides, is especially noteworthy. 

V. H. Aprahamian and D. G. Demopoulos, The Solution Chemistry and Solvent Extraction Behaviour of copper, iron, nickel, zinc, lead, tin, Ag, arsenic, antimony, bismuth, selenium and tellurium in Acid Chloride Solutions Reviewed from the Standpoint of PGM Refining, Mineral Processing and Extractive Metallurgy Review, Vol. 14, p. 143,1995. 

Heise and Litz [26] investigated the extraction behaviour of surfactants (LAS, NPEO and cationics) from sand comparing Soxhlet extraction, accelerated solvent extraction (ASE) and microwave-assisted extraction. Fractionation of the three surfactant types anionic, non-ionic and cationic, was accomplished by column chromatography with aluminium oxide. Soxhlet extraction and ASE of spiked sand with methanol—stored during 7 days prior to extraction—gave similar recoveries for both LAS and NPEO with values between 88 and 116%. Less efficient extraction was achieved by microwave extraction (79% for NPEO). 

Solvent Extraction Behaviour of the Transition Elements. I. Order and Degree of Fractionation of the Rare-Earths. J. physic. Chem. 57, 294 (1953) -... 

Structurally related compounds demonstrate different extraction behaviours in a ternary liquid-liquid extraction system composed of methylene chloride, chloroform and methyl ter/.-butyl ether. In investigations for finding proper internal standards, one should take into account the extraction liquid used for extraction of both analyte and internal standard. 

Separation based on valency change.—The easy oxidation of Ce3 to Ce4+ permits its isolation from other rare earths. The separation of cerium is usually performed by selective leaching with acids, or by complete dissolution [129, 130] followed by hydrolysis. The solvent extraction behaviour of Ce(N03)4 has been extensively studied. Among the various extractants, alcohols, ethers, organic and inorganic acids, ketones etc., TBP proved to be most advantageous in large scale operations [131,132]. 

Spjuth, L., Liljenzin, J-O., Hudson, MJ. et al. 2000. Comparison of extraction behaviour and basicity of some substituted malonamides. Solvent Extr. Ion Exch. 18 (1) 1-23. 

Phal, D.G. Kannan, S. Ramakrishna, V.V. Patil, S.K. Studies on the solvent extraction behaviour of Pu(IV) from sulfuric acid medium into di-2-ethylhexylphosphoric acid (HDEHP), J. Radioanal. Nucl. Chem. 152 (1991) 137-150. 

Fujii, T., Aoki, K., Yamana, H. 2006. Effect of nitric acid distribution on extraction behaviour of trivalent/-elements in a TRUEX system. Solvent Extraction and Ion Exchange 24(3) 347-357. 

Pattern Recognition. In recent years, pattern recognition, an efficient computational method for the analysis of multivariant data, was developed (8). The pattern recognition processing of the influence of various structure factors of some organophosphorus compounds on their extraction behaviour of uranium is described. 

When combination of different extractants, together with a diluent, are employed for the metal ion extraction it is essential to know various intermolecular interactions that take place between them in order to successfully apply the law of mass action to these systems. These include (i) self-association, (ii) association with the diluent and (iii) association between different extractants. While the first two influence the extraction behaviour involving even a single extractant, all of them influence synergism markedly. Some of the representative data are discussed below which enable one to understand the extent of such interactions. 

It can be seen on figure 3, that extraction pressures between 600 and 850 bar give the best results. After an extraction time of one hour, which is a minimum for production plants, an extraction yield of 90% at 700 bar and 80% at 600 bar was obtained. To reach 90% at 500 bar 3 hours are necessary, which is too long for an economical production of a cheap product like coriander extract. The extraction behaviours of nutmeg and mace are similar but the viscosity of extract is higher for nutmeg and lower for mace compared to coriander extract. 

From the results of Figure 14.3, interestingly, the protein extraction behaviour by dilinoleyl phosphoric acid (DLIPA) is distinct from the result obtained by DOLPA, in spite of the similar hydrophobic chain. The oleyl and linoleyl groups are unsaturated C18 chains. The former has one unsaturated cis-double bond at the position between C9 and CIO, while the latter has two at the position between C9 and CIO and between C12 and Cl 3. The two double bonds in the hydrophobic part of the surfactant DLIPA provide some inflexibility in the chain, which can lead to steric hindrance and to solvation by the organic phase (Figure 14.5). 

On the protein extraction behaviour using reverse micelles, the protein-surfactant interaction between charged protein surfaces and surfactant headgroups is a dominant factor in distinguishing the target proteins. In particular, some researchers have suggested that a protein can be extracted as a hydrophobic ion complex between a protein and surfactant molecules [6,7,12-15]. Therefore, an intrinsic factor of proteins also gives considerable modulation in the extraction behaviour, in which the environmental factors were maintained. 

Figure 14.10 shows the extraction behaviours of N-cytc and G-cytc by DOLPA reverse micelles. 

FIGURE 14.10. Extraction behaviour of N-cytc and G-cytc into the organic phase containing DOLPA. The amount of depleted proteins from aqueous solution (open symbols) and extracted proteins in the surfactant solution (closed symbols) were estimated by the decrease and increase in the protein concentration during the extraction operation, respectively [19]. 

In this section, we will introduce the extraction behaviour of DNAs from an aqueous solution into an organic phase using reverse micelles, and show some important... 

Each transuranic element has many valencies and their behaviour in aqueous solution is very complicated because of disproportionation reactions. As stated above, the ion-exchange and solvent-extraction behaviours of transuranics are dependent on their valency state. Therefore valency control is very important in their analysis (Katz et al., 1986). Additional references discussing this problem include Karkisch (1989), Diamond et al. (1954), Stevenson and Nervik (1961), Abuzwidaet al. (1987), Bemabee et al. (1980), Budnitz (1973), Chu (1971), Fukai et al. (1976), Hampson and Tennaut (1973), Hindman (1986), Holm et al. (1979), Irlweck and Veselsky (1975), Jiang et al. (1986), Johns (1975), Scott and Teynolds (1975), Sekine et al. (1987). 

Pathak, P.N., Kumbhare, L.B., and Manchanda, V.K., Stmctural effects in NJV-dialkyl amides on their extraction behaviour towards uranium and thorium. Solv. Extr. Ion Exch., 2001, 19 105-126. 

Weak-acid resins generally extract metal ions only at a pH value of 3 or more. At high pH values, where the carboxylic acid functional group is predominantly ionized, the metal-extraction behaviour of a weak-acid resin parallels that of a strong-acid resin. The weak-acid resins tend to be more selective than strong-acid resins, however, and practical separations of metals are possible. In certain interactions between metal ions and weak-acid resins it is difficult to determine whether the interaction is purely electrostatic or whether chemical bonds are formed. In particular, there is strong evidence that Ag" and Cu + form complexes with carboxylic acid groups. Copper, in... 

When more them one solute is involved in the consideration of the process design, the situation becomes much more complex since the extraction behaviours of the different solutes will usually be interdependent. In the case of irradiated thermal reactor fuels the solvent extraction process will be dealing with uranium containing up to ca. 4% of fission products and other actinides. These will have only a minor effect on uranium distribution so that a single-solute model may be adequate for process design. However, in some cases nitric acid extraction may compete with U02 extraction and a two-solute model may be needed. In the case of breeder reactor fuels the uranium may contain perhaps 20% of plutonium or thorium. Neptunium or protactinium levels in such fuels may also not be negligible and, under these circumstances, the single-solute... 

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