Mixtures Of HTTA Research Articles

Thermodynamics of the extraction of Eu3+ with thenoyltrifluoroacetone, triphenylarsine oxide and other phosphine oxides

Extraction of Eu3+ from 0.1M aqueous perchlorate medium by thenoyltrifluoroacetone (HTTA) and by mixtures of HTTA and tributylphosphate (TBP), HTTA and triphenylphosphine oxide (TPPO), HTTA and trioctylphosphine oxide (TOPO) and HTTA and triphenylarsine oxide (TPAsO) has been studied at various temperatures allowing for the elucidation of the mechanism of extraction in each case and a comparison between the various bases.

2,2′-Dipyridyl and 1,10-phenanthroline in the synergetic extraction of Eu3+

The thermodynamics of the extraction of Eu3+ by thenoyltrifluoroacetone (HTTA) and by mixtures of HTTA and bidentate amine bases such as 2,2′-dipyridyl (Dipy) and 1,10-phenanthroline (Phen) in benzene from an aqueous phase fixed to 0.1M ionic strength (NaClO4), pH 3.9, has been investigated. Phenanthroline forms both the Eu(TTA)3·Phen and Eu(TTA)3·2Phen species, which are much stronger than the dipyridyl complexes. The diluent effect on the extraction is also studied.

Thermodynamics of the extraction of Co2+ by htenoyltrifluoroacetone, 8-hydroxyquinoline and phenanthroline

The extraction of Co2+ from aqueous 0.1M acetate buffer by thenoyltrifluoroacetone (HTTA) and 8-hydroxyquinoline (HQ) and by a mixture of HTTA+phen and HQ+phen in benzene has been studied at various temperatures allowing for elucidation of the thermodynamics of extraction in the cases investigated.

LUMINESCENCE STUDY OF Eu( III) COMPLEXES EXTRACTED IN THE ORGANIC PHASE

ABSTRACT Luminescence lifetimes have been measured for Eu(III) extracted into benzene solutions. The extrac-tants were HDEHP, HTTA, and mixtures of HTTA with crown ethers, TBP, and TOPO. The results were consistent with no residual hydration for Eu(DEHP)3, and three molecules of hydration for Eu(TTA) 3,. The Eu(TTA) 3,-(TOPO)„ n (n = 1,2) complexes have one water molecule or less. The hydration numbers from the luminescence lifetimes compare well with the values from Karl Fischer titrations. The hydration of the crown ether complexes can be related to the degree of steric hindrance by the aliphatic or aromatic groups attached to the crown ethers.

Liquid-liquid extraction of thorium/IV/ with LIX-54 and its mixtures

Solvent extraction of thorium/IV/ by a commercially available chelating extractant LIX-54 /a β-diketone derivative/ /HA/ and its mixtures with tri-n-butyl phosphate /TBP/, thenoyltrifluoroacetone /HTTA/ and tri-n-octyl phosphineoxide /TOPO/ in benzene as the diluent have been studied. Quantitative extraction of thorium/IV/ by the mixture of 10% LIX-54 and 0.1M TOPO was noticed at pH 2.8. Influence of various concentrations of HTTA and TOPO in their mixtures with LIX-54 on the extraction of the same metal ion has been investigated and pronounced synergism was observed. Slope analyses determination shows the extracted species to be possibly of the type [Th/TTA/2/A/2] in case of extraction by mixtures of HTTA and LIX-54. Slopes of the linear plots were computed employing regression analysis, and variance in results has been shown.

Some studies on synergic extraction of mixed ligand species of uranium(VI)

The extraction of U(VI) by mixtures of HTTA and TBP from aqueous thiocyanate medium has been studied. From the data obtained it was observed that the predominant uranium species extracted, causing synergic enhancement in the extraction of U(VI), is UO2(SCN)TTA · 2TBP when benzene and cyclohexane are used as diluents, and that at a very low concentration of TBP the contribution of additional species, viz. UO2(TTA)2 · TBP becomes significant. With chloroform as diluent, however, both of these species are contributing to the synergic enhancement. The extraction of a quaternary uranium species, UO2(SCN)TTA · 2TBP, involving the participation of the aqueous anion is thus established. Equilibrium constants for the various extraction equilibria involved are calculated.

TEMPERATURE EFFECT ON THE SYNERGISTIC SOLVENT EXTRACT ION OF LANTHANOIDES

ABSTRACT The synergistic solvent extraction of Pr, Gd and Yd with mixtures of HTTA and Aliquat 336 in CCl4C6H6 and CHCl3 at 288,298,308 and 318 K has been studied. The values of the equilibrium constants as well as the values of the thermodynamic parameters have been calculated.

Synergic extraction of uranyl perchlorate by the ternary system of AAC species composed of HTTA-HPMBP-(C6H5)4AsCl

A new ternary synergic extract system composed of two chelate extract ligands and one ion association ligand, namely AAC species, was studied. Uranyl perchlorate was extracted by the binary system of thenoyltrifluoroacetone (HTTA) and of 1-phenyl-3-methyl-4-benzoylpyrazol-5-one (HPMBP) with tetraphenylarsonium chloride [(C6H5)4AsCl] in chloroform solution. It was found that synergic effect occurred during the extraction of uranyl perchlorate with the chloroform solution of a mixture of HTTA, HPMBP and (C6H5)4 AsCl and the principle of minimum density of electric charge plays an important role. The formation of a ternary complex (C6H5)4AsUO2(ClO4)(TTA)-(PMBP) was confirmed by the slope method, and the perchlorate was determined by the methylene blue spectrophotometric method. The equilibrium constant was calculated to be log βA1A2C = 5.52.

Synergism in the extraction of lanthanides, copper and thorium in presence ofhtta and antipyrine

Synergism in the extraction of lanthanum, europium, lutetium, copper and thorium has been studied using a mixture ofhtta and 2,3-dimethyl, 1-phenyl pyrazol-5-one (antipyrine). Synergism was observed in all the cases except copper. The nature of extracted species has been determined on the basis of log-log plots and the equilibrium constants for the adducts have been evaluated. Antipyrine has been found to be a good donor comparable in strength to other alkylphosphorus donors.

Spectrophotometric studies on the formation of adducts involved in the extraction of U(VI) by mixtures of HTTA with some neutral extractants

The adduct formation of UO2 (tta)2 with the neutral donorstbp, dbbp andtopo, in benzene, was investigated spectrophotometrically and it was found that each of these donors form a 1∶1 adduct with UO2 (tta)2. It was also shown spectrophotometrically that the adduct UO2(tta)2·S can also be formed, in the organic medium according to the equilibrium, UO2(NO3)2. 2S+2htta+S⇌UO2(tta)2.S+2(HNO3.S)

Synergistic Extraction of Trivalent Actinides by Mixtures of Thenoyltrifluoroacetone and Neutral Oxo Donors

Abstract The synergistic extraction of trivalent actinides Am, Cm, Bk, and Cf has been studied by mixtures of HTTA and TOPO as well as DOSO in xylene at 30°C. HTTA-S (TOPO, DOSO) interaction corrections have been applied to calculate the “free” S concentrations in the organic phase. In the extraction of trivalent actinides, the third-power dependence on [HTTA]org at a fixed [S]org has been observed only after applying this correction. The synergistic species M(TTA)3.S and M(TTA)3.2S were found to be extracted into the organic phase whose stability constants (β1, β2, and K 2) have been evaluated. Extraction by HTTA + S(S = TOPO, DOSO, TBP, TBTP) shows the order of extraction to be Tm > Cf > Bk > Eu > Pm > Am > Cm for the trivalent ions. The Am/Cm separation factor with the synergistic mixtures is ∼3 whereas with HTTA alone it is ∼6 when they are extracted from the chloroacetate buffer.

Synergistic extraction of hexavalent actinides by HTTA and neutral donors—I: U(VI)-HTTA-TBP-benzene system

The synergistic extraction of U(VI) from aqueous nitric acid by mixtures of HTTA and TBP was studied to establish the presence of mixed ligand species, using a method-developed in this laboratory. The results obtained by this method were corroborated with the conventional extraction studies. It was established that the species UO 2(NO 3)(TTA)TBP reported in the literature was not involved in the synergistic extraction and that the only species responsible for synergism was UO 2(TTA) 2·TBP. Equilibrium constants for various equilibria involved are calculated.

Synergistic Extraction of Np(IV) by Mixtures of HTTA and TBP in Chloroform

Abstract Extraction of Np(IV) from perchloric acid medium by chloroform solutions of HTTA and TBP was studied. The species Np(TTA)4TBP was found to be mainly responsible for the observed synergism. Equilibrium constants for the extraction equilibria involved were obtained.

Synergistic Extraction of Pu(IV) by Mixtures of HTTA with TBP and DBBP

Abstract The synergistic extraction of Pu(IV) from perchloric acid medium by mixtures of thenoyltrifluoroacetone (HTTA) and the neutral donors tri-n-butylphos-phate (TBP)and dibutyl butylphosphonate (DBBP) using benzene and cyclo-hexane as diluents was investigated by different solvent extraction methods. With TBP, the adduct responsible for synergism was found to be Pu(TTA)4 TBP. With DBBP, in addition to Pu(TTA)4 DBBP, it was indicated that more species containing perchlorate ion are involved in the extraction. The adduct formation of Pu(TTA)4 with DBBP in benzene was also investigated by spectrophotometry. The equilibrium constants for several equilibria involved were obtained.

Synergistic extraction of hexavalent actinides by HTTA and neutral donors-II

Synergistic extraction studies on Np(VI) and Pu(VI) have been carried out as a part of the programme on the synergistic extraction of hexavalent actinides. Extraction of Np(VI) and Pu(VI) were carried out by mixtures of HTTA and TBP in benzene from aqueous perchlorate and nitrate media. Equilibrium constant values for the various reaction equilibria involved were calculated from the data obtained by using slope-ratio as well as Job’s method. The extraction of Np(VI) by the synergistic mixture from 1M nitric acid indicated that the species NpO2 (TTA) (NO3). TBP was not involved in the extraction. The log values of KA, KAB and βAB were −1.5, 2.92 and 4.43, respectively for Np(VI) and −1.63, 2.50 and 4.13 respectively for Pu(VI).

Thermodynamic studies of TOPO adducts of europium and terbium tris-TTA chelates

Solvent extraction of Tb 3+ and Eu 3+ from an aqueous phase of 0.1 M ionic strength (NA +, HClO 4) and pH = 3.4 with thenoyltrifluoroacetone, HTTA, in benzene and by mixtures of HTTA and trioctylphosphine oxide, TOPO were made at different temperatures. The thermodynamic data obtained explain the mechanism of formation of the species Eu(TTA) 3 (TOPO), Eu(TTA) 3(TOPO) 2, Tb(TTA) 3(TOPO) and Tb(TTA) 3(TOPO) 2.

Spectrophotometric studies on the formation of adducts between U(TTA) 4 and some neutral donors

Formation of adducts of U(TTA) 4 with neutral donors TOPO, DBBP and TIOTP in benzene medium was studied by spectrophotometry and it was shown that each of these donors forms only 1:1 adduct with U(TTA) 4. The adduct formation constants were evaluated from the spectral changes and were found to be 1.7 × 10 6 (TOPO) 1.1 × 10 4 (DBBP) and 11 (TIOTP). The studies indicated that these adducts are involved in the synergistic extraction of U(IV) by mixtures of HTTA and neutral donors. The extraction equilibrium constants were calculated. The spectra indicated that the adduct formation results in the increase of coordination number of the U(IV) from 8 to 9.

Synergistic Extraction of Th(IV) by Mixtures of HTTA and TBP in Benzene

Extraction of Th(IV) from dilute perchloric acid medium by mixtures of HTTA and TBP in benzene medium was studied. The species Th(TTA)/sub 4/ TBP was found responsible for the observed synergism. Equilibrium constants for the extraction equilibria involved are log K/sub A/ = 2.25, log K/sub AB/=6.88, and log ..beta../sub AB/= 4.63. 2 figures, 4 tables.

Studies on synergistic extraction of thorium by mixtures of HTTA and TBP

Synergistic extraction of Th(IV) from perchlorate medium by mixtures of HTTA and TBP was studied. These studies include the effect of the ionic strength, temperature and the diluents on the extraction. Ionic strength was found to influence the extraction of Th(TTA)4 and Th(TTA)4·TBP whereas the adduct formation in the organic phase was almost unaffected. Increase of temperature resulted in a decrease of the extraction of Th(IV). The stability of the adduct was found to decrease in the order, cyclohexane > benzene > chloroform.

Spectrophotometric studies on the formation of adducts involved in synergistic extraction of uranium(IV) by mixtures of HTTA and neutral donors

Formation of adducts between U(TTA)4 and several neutral donors was studied by spectrophotometry and it was shown that each of the neutral donors forms only 1∶1 adduct with U(TTA)4. The adduct formation constants with some neutral donors were determined for benzene and chloroform media. As these adducts are involved in the synergistic extraction of U(IV) from aqueous media by mixtures of HTTA and neutral donors dissolved in organic solvents, the extraction equilibrium constants were estimated, The adduct formation was found to result in an increase of the co-ordination number of U(IV) from 8 in U(TTA)4 to 9 in the adducts it forms with the neutral donors. Similar absorption spectral studies with U(DBM)4 revealed that it forms much weaker adducts than the corresponding ones with U(TTA)4.