SYNERGISTIC EXTRACTION OF EUROPIUM(III) WITH BENZOIC ACID AND THENOYLTRIFLUOROACETONE

ABSTRACT

The solvent extraction of europium(III) into solutions of thenoyltrifluoroacetone and benzoic acid in cyclohexane, carbon tetrachloride, benzene, chloroform, pentachloroethane, and tetrachloroethane has been measured at 25°C. It has been found that the extracted species involve two types of adducts, EuA₃· HB and EuA₃· 2HB where A denotes the TTA anion and HB the benzoic acid monomer. The magnitude of the adduct formation constants in different solvents has been correlated with the dimerization constants of benzoic acid in the solvents.     

钴镍协同萃取体系

评述了自１９６６年以来报道的有关钴镍协同萃取的文献．主要介绍了磷酸、羧酸以及磺酸类萃取剂与含氮螯合萃取剂或非螯合萃取剂组成的协同萃取体系．此外，对一些由胺类萃取剂加磺酸或羧酸类萃取剂加吡啶羧酸酯组成的协同萃取也作了简单介绍．讨论了这些协同萃取体系萃取钴镍的反应机理、特点及其潜在的应用价值．     

EXTRACTION OF URANYL IONS BY SYNERGISTIC MIXTURES OF THENOYLTRIFLUOROACETONE AND MACROCYCLIC DONORS

A linear polyether, 1, 13-bis[8-qulnoly]-l,4,7,10,13-pentaoxa-trldecane (K-5) and an aza-crown ether, 4,13-didodecyl-1,7,10,16-tetraoxadiazacyclooctadecane (K22DD) when combined with thenoyltrlfluoroacetone (HTTA) have been shown to exhibit a synergistic effect on the extraction of uranyl ion. The effects of the addition to the organic phase of K-5, K22DD, and tert-butylcyclohexyl-15-crown-5 (15-C-5) on the extraction of UO₂ ⁺² by HTTA in chloroform from 0.5 M NaNO₃ at 25°C have been measured. The results indicate the extraction is enhanced by the formation of an adduct, UO₂(TTA)₂S for K-5 and K22DD. No enhancement of the extraction was seen with the crown ether. The organic phase stability constants for both K-5 and K22DD were evaluated and found to be similar in magnitude. These results suggest that the major factor in the formation of the synergistic adduct is the presence of the nitrogen atom in the synergist.     

SYNERGISTIC EXTRACTION OF Eu(III) AND Am(III) BY THENOYLTRIFLUOROACETONE AND NEUTRAL DONOR EXTRACTANTS: (CARBAMOYLMETHYL)PHOSPHINE OXIDE AND 2,6-BIS((DIPHENYLPHOSPHINO)METHYL)PYRIDINE N,P, P-TRIOXIDE

ABSTRACT

Solvent extraction of Eu(III) and Am(III) from weakly acidic solutions with octyl(phenyl)-N, N-diisobutylcarbamoylmethylphosphine oxide (CMPO) and 2,6-bis((diphenylphosphino)methyl)pyridine N, P, P-trioxide (NOPOPO) in 1,2-dichloroethane was studied on a comparative basis. NOPOPO was found to exhibit unusually high extractability for Eu(III) and Am(III), probably due to its trifunctional nature, sufficient steric flexibility and basicity of the functional groups. Both CMPO and NOPOPO demonstrated synergistic effects in extraction of Eu(III) and Am(III) when used in combination with thenoyltrifluoroacetone (HTTA). However, the stoichiometry of the extracted species with CMPO/HTTA and NOPOPO/HTTA was different under similar experimental conditions. The extractant dependencies of the synergistic extractions suggest that the extracted species are the adduct complexes, M(ClO₄)(TTA)₂(CMPO)₂ and M(ClO₄)₂(TTA)(NOPOPO)₂, respectively. It was also observed that CMPO and CMPO/HTTA in dichloroethane extracted Eu(III) and Am(III) equally well, with very similar extraction constants. However, NOPOPO and NOPOPO/HTTA in dichloroethane demonstrated a slight preference for Eu(III) over Am(III), with the extraction constants for Eu(III) more than one order of magnitude higher than that for Am(III).     

INFLUENCE OF THE AMMONIUM SALT ANION ON THE SYNERGISTIC SOLVENT EXTRACTION OF LANTHANIDES WITH MIXTURES OF THENOYLTRDJLUOROACETONE AND TRIDECYLAMINE

ABSTRACT

The synergistic solvent extraction of Pr, Gd and Yb with mixtures of thenoyltnfluoroacetone ( HTTA) and primary ammonium salt ( tridecylammonium chloride or perchlorate, TDAH( C1, CI0) in dHhas been studied. The composition of the extracted species have been determined as Ln( TTA)₃ TDAHA( A= CI or CIO⁴ ) The values of the equilibrium constant K_{T. s} have been calculated. The influence of the ammonium salt anion on the extraction process has been discussed. The separation factors of the pairs Gd/ Pr and Yb/ Gd have been determined.     

EXTRACTION OF TRIVALENT LANTHANIDES AND ACTINIDES BY A SYNERGISTIC MIXTURE OF THENOYLTRIFLUOROACETONE AND A LINEAR POLYETHER

Abstract

Mixtures of a linear polyether, l,13-bis[8-quinolyl]-l,4,7,10,13-pentaoxatridecane, K-5, and thenoyltrifluoroacetone, HTTA, have been shown to exhibit synergistic character in the extraction of trivalent lanthanides and actinides. The effect of the addition of K-5 to the organic phase on the extractions of Ce(III), Eu(III), Tm(III), Am(III), Cm(III), Bk(III), and Cf(III) by HTTA in chloroform from 0.5M NaNO₃ at 25°C has been measured. These results indicate the extraction is enhanced by the formation of M(TTA)₃K-5 adduct in the organic phase. The organic phase stability constants for the formation of these synergistic species have been calculated for all the metals studied. The magnitude of these organic phase stability constants for K-5 are similar to other common neutral donors. The order of stability does not follow the normal trend based on charge-to-radius ratio, but follows a pattern based on size, with Am(III) being the most stable.     

SYNERGISTIC EXTRACTION OF LANTHANIDES(III) BY TRIOCTYLMETHYLAMMONIUM NITRATE AND TRIBUTYL PHOSPHATE

ABSTRACT

The synergistic action of tributyl phosphate in the extraction of La(III), Pr(III)Nd(III), Sm(III), Eu(III), Gd(III), Dy(III), Ho(III), Er(III)and Y(III) with trioc-tylmethylammonium nitrate was studied. The synergistic effect is diluent dependent. It is pronounced with a mixed dodecane/xylene diluent, and is weak with mixed heptane/xylene and hexane/xylene diluents as well as with pure xylene diluent. Two or three synergistic complexes are formed simultaneously in the organic phase. Their composition is (A₊)(Ln(N0₃)) ₄),.2B~), (A₊))(Ln(N0₃))J.3B"), and (A₊)) ₂) (Ln(N0₃)) ₅).BJ-) (Ln is a lanthanide(IM), A+ is a trioc-tylmethylammonium cation and B is a tributyl phosphate molecule). The stability of the synergistic complexes generally decreases with increasing atomic number of the lanthanides(III). The synergism enhaces the efficiency of the lanthanide(III) extraction with trioctylmethylammonium nitrate, but deteriorates its selectivity. The separation factors for the Pr(III)-Nd(III) and Eu(III)-Gd(III) pairs are gradually suppressed at increasing concentration of tributyl phosphate.     

KINETIC STUDIES OF THE SOLVENT EXTRACTION OF PLATINUM(II) WITH DIPHENYLTHIOUREA

The race of extraction of plaCinum(II) wich diphenylthiourea (DPTU) into chloroform has been evaluated as a function of [DPTU]₀, [Cl] and the solution pH at 25° C. The homogeneous chemical reaction:

PtCl^? ₃ + DPTU → PtC1₃(DPTU)^?

is considered to be the rate determining step with a rate constant of 17.2 M^-1s^-1 The role of tetraheptylammonium chloride (THA^?,C1), thiourea (TU), thiocyanate, and iodide in catalyzing the extraction is examined.     

RECENT ADVANCES IN THE SOLVENT EXTRACTION OF MERCURY(II) WITH CALIXARENES AND CROWN ETHERS

This work is focused on the recent advances, mainly achieved during the past ten years on the solvent extraction separation of mercury from aqueous solutions using macrocyclic ligands such as calix[n]arene derivatives and crown ethers.     

SOLVENT EXTRACTION EQUILIBRIA OF LEAD(II) WITH ACIDIC ORGANOPHOSPHATE AND PHOSPHONATE

Distribution equilibria of lead(II) in the extraction with di(2-ethylhexyl)phosphoric acid and 2-ethylhexyl 2-ethylhexylphosphonic acid in toluene from aqueous ammonium nitrate solutions were measured at 303 K to elucidate the concentration dependencies of the reactant species on the distribution ratio. It was found that lead(II) is extracted as the mononuclear complex, PbR₂2HR, with the former extrac-tant while it is extracted not only as the complex, PbR₂2HR, but also as the complex, Pb(NO₃)R;HR, accompanied by simultaneous transfer of nitrate anion with the latter ex-tractant. The extraction equilibrium constants of these complexes were evaluated as well as the stability constants of lead(II) -nitrato complexes, Pb(NO₃)⁺, Pb(NO₃)₂and Pb(NO₃)^? ₃.     

SOLVENT EXTRACTION OF Ni(ll) WITH THE ACTIVE COMPONENT OF LIX 54

ABSTRACT

The solvent extraction of Ni(II) with the active component of the commercial extractant Lix 54 in different synergic mixtures, using tri-n-octylphosphine oxide (TOPO), tri-n-laurylamine (TLA), di-(2-ethylhexyl)phosphoric acid (HDEHP), tributylphosphate (TBP) and 4-methylpyridine as synergic reagents is compared in this work, the highest synergic effects corresponding to the presence of TOPO and 4-methylpyridine. For this reason, the extraction of Ni(ll) from a 1.0 mol.dnr³ KN0₃media by the mixture of the active component of Lix 54 and 4-methylpyridine has been extensively studied in this work. The results have been treated both graphically and numerically in order to find a suitable chemical model of the species responsible for the extraction as well as their extraction constants.     

SYNERGISTIC SOLVENT EXTRACTION OF LANTHANIDES WITH MIXTURES OF 1-PHENYL-3-METHYL-4-BENZOYL-PYRAZOL-5-ONE AND ALIQUAT 336

The solvent extraction of Pr(III),Gd(III) and Yb(III) With 1-phenyl-3-methyl-4-benzoyl-pyrazol-5-one (HP) and Aliquat 336(QCl) in CCl₄.C₆H₆ and CHCl₃, has been studied.The composition of the extracted species has been determined as LnP₄ ^?.Q⁺ (Ln=Pr,Gd and Yb).The values of the equilibrium constants have been calculated. The extraction mechanism has been discussed.     

SOLVENT EXTRACTION OF MOLYBDENUM (VI) WITH LIX 63

The equilibrium and kinetics of the extraction of molybde-num(VI) with LIX 63 was investigated. The extraction of Mo(VI) is both favored by high acidity and high LIX 63 concentration. From the equilibrium studies, the extraction constant for the reaction was found to be log K_ex - 16.43. The rate of extraction is first ex order in both metal and extractant but decreases non-linearly with pH. The rate-determining step of the reaction was deduced to be the formation of a 1:1 complex between Mo(VI) and LIX 63 in the aqueous phase. A mechanism in which different Mo(VI) species react concurrently with the neutral ligand is proposed. The logarithmic values of the second order reaction rate constants (in M^?1 s^?1 units) involving each Mo(VI) species are as follows: molybdate - 2.30, bimolybdate - 5.82, and molybdic acid - 8.16. These results agree well with the results reported for other ligands.     

SOLVENT EXTRACTION EQUILIBRIA OF GALLIUM (III) WITH ACIDIC ORGANOPHOSPHORUS COMPOUNDS FROM AQUEOUS NITRATE MEDIA

A comparative investigation on the solvent extraction equilibria of gallium(III) from aqueous nitrate media was conducted with three kinds of acidic organophosphorus compounds, di (2-ethylhexyl) phosphoric acid (D2EHPA), 2-ethylhexyl 2-ethyl-hexylphosphonic acid (EHEHPA) and di (2,4,4'-trimethylpentyl) phosphinic acid (DTMPPA), in toluene at 303 K. It was found that gallium(III) is extracted as 1:4 metal:reagent complexes with D2EHPA and EHEHPA and as a 1:3 complex with DTMPPA in the region of low loading ratio while it is extracted as 1:3 complexes with all reagents at high loading ratio. The extraction equilibrium constants with these extractants were evaluated for the former complexes as follows: K_e = 2.3xl0^-2, 8.5xl0^-3 and 1.3xl0^-4 for D2EHPA, EHEHPA and DTMPPA respectively.     

SYNERGIC EXTRACTION OF COBALT(II) BY STRUCTURALLY RELATED CROWN ETHERS AND THENOYLTRIFLUOROACETONE

ABSTRACT

Cobalt (II) was extracted from perchlorate aqueous media by thenoyltrifluoroacetone (HTTA)alone and mixed with 12-Crown-4 (12C4) 15-Crown-5 (15C5) 18-Crown-6 (18C6)dibenzo-18-Crown-6 (Dbl8C6)dicyclohexyl-18-Crown-6 (Dchl8C6) or dicyclohexyl-24-Crown-8 (Dch24C8), in chloroform. The extraction constant of the chelate (K20) the extraction constant of the mixed species (K21), the synergic factor (S.F.) and the formation constant of the extracted adducts (β₂₁) were evaluated. The adduct stoichiometry was found to have the general formula Co(TTA)₂CE, irrespective of the crown ether (CE) used. It was found that no specific cavity size is required for the adduct formation. The synergic values K₂₁, S.F., and β₂₁as related to the crown ether took the order Dch24C8 > 18C6 > Dchl8C6 > 15C5 > Dbl8C6 > 12C4, which could be explained in terms of the crown ether basicity rather than the correspondence between the cavity size of the crown ether and the cobalt(II) crystal radii. The sequence 18C6 > Dchl8C6 > Dbl8C6 was interpreted in terms of the withdrawing ability of Dch and Db as substitutes in reducing the basic character of the adjacent crown ether oxygen donors.     

SOLVENT EXTRACTION OF COPPER (II) WITH AN ALDOXIME FROM HYDROCHLORIC AND HYDROBROMIC ACIDS

2-ethylhexanal oxime was synthesized to examine the selectivities for various metals in the extractions from hydrochloric acid. It was found to be highly selective for palladium(II) over platinum(II and IV) and other base metals including copper(II), zinc and aluminum, especially in the low concentration region of chloride ions.     

PALLADIUM WITH TRIOCTYLMETHYLAMMONIUM CHLORIDE SOLVENT EXTRACTION OF PALLADIUM(II) WITH TRIOCTYLMETHYLAMMONIUM CHLORIDE

Equilibrium distribution of palladium(II) was investigated in the solvent extraction with tri-octylmethylammonium chloride (QC1) in toluene from hydrochloric acid solutions at 303 K. The title extracting reagent extracted hydrochloric acid as the species of the types, QC1(HC1) (_n(n= 1,2), according to the similar extraction reactions as observed in the extraction of organic acids such as acetic acid and phenol with high-molecular-weight amines in the previous works. From the concentration dependencies of the reactant species on the distribution ratio and from the result of loading test, it was elucidated that palladium(II) is extracted as a mononuclear ion pair complex of the type, Q⁺;[PdCl]₃ (HCl)] in the very high concentration region of hydrochloric acid. The equilibrium constant of the extraction reaction was evaluated.     

SOLVENT EXTRACTION OF PALLADIUM(II) WITH A SULFUR-CONTAINING CARBOXYLIC ACID

The mechanism of solvent extraction of palladium (II) from aqueous ammonium chloride solution with α-butylthiolauric acid( α-BTLA = S) in toluene was investigated in terms of extraction equilibrium and kinetics at 303 K. From the results of extraction equilibrium, it was found that α-BTLA behaves as a solvating extractant for palladium(II) and that the extracted species is a 1:2 metal:reagent complex, PdCl₂S₂ The extraction rate of palladium(II) was measured in a batch-type vigorously stirred cell. The effects of the concentrations of palladium(I I), hydrogen ion, chloride ion and extractant on the extraction rate were quantitatively interpreted by a reaction mechanism where the parallel reactions of α-BTLA with PdCl₃(H₂0)- and PdCl₄ ^2- are the rate-determining steps.     

SOLVENT EXTRACTION OF LANTHANIDES WITH N-m-AND N-p-METHOXYBENZOYL-N-PHENYLHYDROXYLAMINE

The solvent extraction of lanthanides with N-o-methoxy-(o-MBPHA), N-m-methoxy- (m-MBPHA) and N-p-methoxybenzoyl-N-phenylhydroxylamine (p-MBPHA), respectively, in chloroform was studied. The selected lanthanides (Yb, Ho, Eu, Pr and La) were all found extract with m- and p-MBPHA as self-adducts of the form LnL-2HL, where L and HL denote the ligand anion and neutral ligand, respectively. The extraction constant and separation factors for the lanthanides with m- and p-MBPHA were evaluated.     

INVESTIGATION OF SOLVENT LOSSES IN THE SOLVENT EXTRACTION OF BORON

ABSTRACT

Solubility, adsorption onto mineral particles and entrainment of 2-chloro-4-(1,1,3,3-tetramethy1-buty1)-6-methylol-phenol (CTMP) in aqueous slurry phase are considered here.

The results show that, the solubility at equilibrium increased sharply with pH, but remained at only 16 parts per million (ppm) at pH 9. With regard to adsorption onto various mineral phases considered, the affinity for CTMP increases in the order quartz < clay minerals < carbonates. The adsorption is about 9 and 13?ppm for quartz and bentonite respectively. The entrainment at pH 9.2 is about 107 and 110 gm^-3 for bentonite and the Kirka slurry respectively