Synergistic extraction of americium(III) with 2-thenoyltrifluoroacetone and crown ethers

Extracton, of Am³⁺ in benzene with 2-thenoyltrifluoroacetone (HTTA) and crown ethers (CEs) such as 15-crown-5, 18-crown-6, dicyclohexano-18-crown-6, dibenzo-18-crown-6, dicyclohexano-24-crown-8, and dibenzo-24-crown-8 was investigated. Synergistic effect by CE was observed regardless of the kind of CE examined. The extracted species was found to be Am(TTA)₃(CE), and adduct formation constants between Am(TTA)₃ and CE in the organic phase were determined. The sequence of constant could not be explained only by basicity of CE and the steric effect of CE should be taken into account to elucidate the adduct complex formation.     

Synergistic effect of 3,5-dichlorophenol and trioctylphosphine oxide on the extraction of vanadium(V) with 2-methyl-8-quinolinol derivatives.

The extraction of vanadium(V) with 2-methyl-8-quinolinol derivatives (HA), such as 2-methyl-8-quinolinol (HMQ), 2-methyl-5-butyloxymethyl-8-quinolinol (HMO4Q), and 2-methyl-5-hexyloxymethyl-8-quinolinol (HMO6Q), from a weakly acidic solution into chloroform was studied in both the absence and presence of 3,5-dichlorophenol (Hdcp) and trioctylphosphine oxide (TOPO) as the synergists. Vanadium(V) was extracted with HA as VO(OH)(A)2 in the absence of synergists, and its extractability increased with an increase in the hydrophobicity of HA. Vanadium(V) was quantitatively extracted from the lower pH region upon the addition of Hdcp and TOPO as VO(OH)(A)2 x Hdcp and VO2(A)(TOPO), respectively. The enhancement of the synergistic effect of Hdcp on the extraction of vanadium(V) with HA increased in the following order: HMQ < HMO4Q < HMO6Q, as opposed to that of TOPO. This result was ascribable to the difference in the mechanisms of the occurrence of the synergistic effect by Hdcp and TOPO.     

Solvent extraction of U(VI) by trioctylphosphine oxide using a room-temperature ionic liquid

The unique physical and chemical properties of room-temperature ionic liquids(RTILs) have recently received increasing attention as solvent alternatives for possible application in the field of nuclear industry, particularly in liquid-liquid separations of radioactive nuclides. We investigated solvent extraction of U(VI) from aqueous solutions into a commonly used ionic liquid 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide([C4mim][NTf2]) using trioctylphosphine oxide(TOPO) as an extractant. The effects of contact time, TOPO concentration, acidity, and nitrate ions on the U(VI) extraction are discussed in detail. The extraction mechanism was proposed based on slope analysis and UV-Vis measurement. The results clearly show that TOPO/[C4mim][NTf2] provides a highly efficient extraction of U(VI) from aqueous solution under near-neutral conditions. When the TOPO concentration was 10 mmol/L, the extraction of 1 mmol/L U(VI) was almost complete( 97%). Both the extraction efficiency and distribution coefficient were much larger than in conventional organic solvents such as dichloromethane. Slope analysis confirmed that three TOPO molecules in [C4mim][NTf2] bound with one U(VI) ion and one nitrate ion was also involved in the complexation and formed the final extracted species of [UO2(NO3)(TOPO)3]+. Such a complex suggests that extraction occurs by a cation-exchange mode, which was subsequently evidenced by the fact that the concentration of C4mim+ in the aqueous phase increased linearly with the extraction percent of U(VI) recorded by UV-Vis measurement.     

Synergistic effect of heterocyclic bidentate amines on the extraction of thorium(IV) with 2-thenoyltrifluoroacetone

The synergistic effect on the extraction of thorium(IV) was found by the combination of 2-thenoyltrifluoroacetone (Htta) and 1,10-phenanthroline (phen) or 4,7-diphenyl-1,10-phenanthroline (dpp) as a neutral bidentate ligand. Especially in the presence of dpp (1·10^–3M) in benzene, the distribution ratio of thorium(IV) increased by a factor of about 300. Such synergistic enhancement of the extraction was ascribed to the formation of the adduct complex of Th(tta)₄(phen) and Th(tta)₄(dpp) in the organic phase. The extraction constant and the adduct formation constant were determined and discussed.     

Selective extraction of the transplutonium and rare-earth elements by trioctylphosphine oxide

In the studies of nuclear reactions of heavy ions with heavy nuclei it is often necessary to determine the yields of TPE. Trioctylphosphine oxide (TOPO) has high selectivity with respect to trivalent TPE and rare earths. The possibility of using target or catcher materials as salting-out agents in the extraction of TPE with TOPO from solutions containing DTPA and lactic acid was investigated. The influence of the concentration of Pb, Bi, Cu, Ni, nitric acid and TOPO on the distribution coefficients was established. The advantages of application of the method for the extraction chromatographic separation of TPE and rare earths from the other elements produced in the interaction of ions with heavy elements are shown.     

Synergic extraction of lanthanoid(III) with 2-thenoyltrifluoroacetone and triphenylarsine oxide in benzene

The synergic extraction of La(III), Eu(III), and Lu(III) with 2-thenoyltrifluoroacetone (Htta) and triphenylarsine oxide (tpao) in benzene has been studied. The extractability of lanthanoids, Ln(III), is significantly affected by the association of Htta with tpao in the organic phase. The associated species is Htta·tpao and the association constant is determined as 10^1.63. The intrinsic extraction equilibrium of Ln(III) is analyzed using the free concentration of Htta and tpao. The synergic enhancement is ascribable to the formation of the adduct complexes shown as Ln(tta)₃tpao and Ln(tta)₃(tpao)₂ in the present extraction system. The adduct formation constants determined are very large as expected from the high basicity of tpao.     

磷酸三丁酯萃取苯酚的研究

溶剂萃取法处理含酚废水一般选用醋酸丁酯.甲基异丁基酮和异丙醚等N,N,-二甲基庚基乙酰胺(N503)萃取酚已得到实际应用,但酮类水溶性较大,醋酸丁酯等萃取酚的分配系数不及取代酰胺类,常用萃取剂磷酸三丁酯(TBP)也具有良好的萃取脱酚性能,已有磷类萃取剂萃取酚的报道.本文考虑了TBP萃取苯酚的性能,通过在不同温度下分配比的测定,求得萃取反应的热力学函数.用斜率法.连续变量法研究了萃合物的组成,并根据IR和1H NMR讨论了萃取过程与萃合物的结构.     

Liquid-liquid extraction of lead(II) with tributyl phosphate

Tributyl phosphate [30% solution in isobutyl methyl ketone (IBMK)] is used for the quantitative extraction of microgram amounts of lead from 3M hydrochloric acid containing lithium chloride (2M) as salting-out agent. It is then stripped from the organic phase with water and determined colorimetrically as its orange-red complex with 4-(2-pyridylazo)resorcinol at 520 nm. TBP alone cannot quantitatively extract lead in the absence of salting-out agents. The IBMK used as diluent does not extract lead under the conditions used. The period of equilibration needed is 5 min. Lead can be extracted in the presence of up to 100 times as much of certain other ions. The method is found to be applicable to analysis of gun-metal.     

Kinetics of zinc(II) cloride extraction with tributyl phosphate

The equilibrium and rate of solvent extraction of zinc chloride complexes from HCl solutions into benzene solutions of tributyl phosphate (TBP) have been studied. The extracted species are discussed in the light of the results. The extraction was found to be first order with respect to both Zn(II) and TBP, and zero order for HCl. The rate-controlling steps are discussed and the rate constants for these reactions are calculated.     

Investigation of radiochemical conversions in extraction systems based on tributyl phosphate

The use of halogenated organic compounds under the effect of ionizing radiation requires a comprehensive knowledge of their radiation stability. There is little experimental evidence on the radiolysis of fluorine-containing organic compounds in the literature, while a theoretical generalization enabling one to predict the main radiolysis pathways is completely lacking. This paper is concerned with the identification of stable radiolysis products of trichloromethyl-1,1,2-trifluoro-2,2-dichloroethyl ether (C₃F₃Cl₅ O), γ-irradiated separately and the extraction system based on tributyl phosphate. Practically all the C₃F₃Cl₅O radiolysis products were identified with the aid of gas-liquid chromatography, GC-MS, IR, UV and NMR spectroscopy and elemental analysis. Upon C₃F₃Cl₅O radiolysis, the formation of CCl₄, Cl₂, COCl₂, C₂ Cl₆, freons of various composition and long-chained ethers like CFCl₂−CF₂−O−CCl₂−CCl₃ takes place. The identification of radiolysis products allows to draw well-founded conclusions on the mechanism of C₃F₃Cl₅O radiolysis, representing a wide class of chlorine- and fluorine-containing organic compounds.     

Studies on extraction of indium by tributyl phosphate from thiocyanate solutions

Indium can be quantitatively separated from a large number of elements which are usually associated with it, by extraction with 15% tributyl phosphate solution in kerosene from hydrochloric acid (pH 1)/0.5M potassium thiocyanate medium and stripping with 6M nitric acid. The equilibration takes 20 min.     

Liquid-liquid extraction of arsenic(III) with diluted tributyl phosphate

A 40% tributyl phosphate solution in xylene was used for the quantitative extraction of arsenic(III) from 4M hydrochloric acid/2M lithium chloride. It was stripped from the organic phase with water and determined volumetrically with potassium bromate. The period of equilibration was 3 min. Arsenic was extracted in presence of copper, cobalt, nickel, tin, bismuth, iron, cadmium and other elements which are usually associated with it in sulphide minerals and alloys.     

The use of trioctylphosphine oxide for solvent extraction recovery and purification of transplutonium elements

Extraction of trivalent curium, berkelium, californium, einsteinium, and europium with trioctylphosphine oxide (TOPO) from nitric acid solutions as well as extraction of curium and cerium from lactic acid solutions containing DTPA depending on aluminium nitrate concentration have been studied. The distribution of cobalt, nickel, chromium, iron, aluminium, titanium, zirconium, and niobium ions has been studied and coefficients of berkelium purification from the elements studied have been determined under the conditions of extraction-chromatographic recovery of berkelium. The influence of weighed amounts of the same impurities on the yield of berkelium in its extraction-chromatographic separation has been studied. Some examples of the practical application of the extraction-chromatographic techniques using TOPO are given.     

Solvent extraction of gallium(III) with 2-thenoyltrifluoroacetone

Gallium can be quantitatively extracted at trace levels with 2-thenoyltrifluoroacetone in xylene at pH 4.5-6.0. Gallium is determined in the organic phase photometrically by complexation with Rhodamine B. The system conforms to Beer's law (at 565 nm) in the concentration range 2-59 mug ml . The complex is stable for 24 hr. Salting-out agents have no effect on the extraction. Gallium can be extracted and determined in a single extraction in presence of many elements associated with it, such as indium, thallium and aluminium.     

In situ electro-oxidation and liquid-liquid extraction of cerium(IV) from nitric acid medium using tributyl phosphate and 2-ethylhexyl hydrogen 2-ethylhexyl phosphonate

The process of in situ electro-oxidation of Ce(III) to Ce(IV) followed by its extraction into the organic phase has been investigated for its applicability in the separation of Ce from nitrate medium. Solvent extraction of cerium from nitric acid after its electro-oxidation to fourth valency state was carried out using tributyl phosphate (TBP) and 2-ethylhexyl hydrogen 2-ethylhexyl phosphonate (KSM-17, equivalent to PC-88A). The efficiency of the extractants at different aqueous phase nitric acid concentrations and different electrode potentials were determined. Various reducing agents such as hydroxylamine hydrochloride, sodium nitrite, ferrous sulphate as well as complexing agents like EDTA, oxalic acid etc, were studied as strippants for the back extraction of cerium from the loaded organic phase. The method developed for the extraction of cerium was further extended to the partitioning of cerium from Ce-Am mixture obtained during the KSM-17 based extraction chromatographic elemental fractionation of PUREX High Activity Waste (HAW) solutions. Recovery of Ce obtained in the extraction experiments by batch as well as by continuous flow organic phase was >95% with good radiochemical purity.     

Behavior of nitrite forms of nitrosylruthenium on extraction and back extraction of heterometalic Ru/Zn complexes with trioctylphosphine oxide

The state of ruthenium in conjugated phases upon extraction of trans-[Ru(¹⁵NO)(¹⁵NO₂)₄(OH)]^2? complex with tri-n-octylphosphine oxide (TOPO) in the presence of Zn²⁺ and subsequent back extraction with H¹⁵NO₃ and NH₃(concd.) solutions was studied by ¹⁵N NMR. Binuclear complexes [Ru(NO)(NO₂)_5?n (μ-NO₂) _n?1(μ-OH)Zn(TOPO) _n ] and [Ru(NO)(NO₂)_4?n (ONO)(μ-NO₂) _n?1(μ-OH)Zn(TOPO) _n ], where n = 2, 3, are predominant forms in extract. Kinetic restrictions for ruthenium extraction with TOPO solution in hexane and its back extraction with aqueous solutions of nitric acid and ammonia are eliminated in the absence of direct coordination of extractant to ruthenium. fac-Dinitronitrosyl forms [Ru(NO)(H₂O)₃(NO₂)₂]⁺, [Ru(NO)(H₂O)₂(NO₂)₂(NO₃)]⁰ (3 and 6 M HNO₃) and [Ru(NO)(H₂O)(NO₂)₂(NO₃)₂]^? (6 M HNO₃) prevail in nitric acid back extracts. Equilibrium constant at ambient temperature (0.05 ± 0.01) was assessed for the coordination of second nitrate ion to nitrosylruthenium dinitronitrato complex. Complex species [Ru(NO)(NO₂)₄(OH)]^2? and [Ru(NO)(NO₂)₃(ONO)(OH)]^2? prevail in ammonia back extract.     

Extraction-chromatographic separation of uranium from long-lived fission products using tributyl phosphate

Extraction-chromatographic separation of uranium from fission products was performed using undiluted tributyl phosphate sorbed on Chromosorb W as a stationary phase, and nitric acid (1: 3) as a mobile phase. Most of the fission products that contributed greatly to the radiation level of the sample passed through the column; this effected considerable decontamination. Uranium retained on the column was quantitatively recovered by elution with water.     

Reversed-phase extraction chromatography of Germanium(IV) with tributyl phosphate on silica gel

Germanium(IV) can be separated by reversed-phase extraction chromatography with TBP as stationary phase on a column of silica gel, with 6M hydrochloric acid as the mobile phase, and stripped with various eluents. Germanium can thus be separated (by selective extraction) from those elements which are not extractable with TBP, and (by selective stripping) from elements that are extractable.     

Selective extraction and spectrophotometric determination of titanium(IV) with 2-thenoyltrifluoroacetone

A new rapid method is suggested for simultaneous extraction and spectrophotometric determination of titanium with 2-thenoyltrifluoroacetone (TTA). The greenish-yellow chelate of titanium(IV)-TTA can be extracted with isoamvl alcohol-benzene and measured at 430 mm. The extraction can be carried out in presence of Al, Cr(III), Th, Zr, Mo, W, borate, phosphate, citrate, tartrate and EDTA.