MECHANISTIC STUDIES ON THE EXTRACTION OF PALLADIUM )II) WITH 2-HYDHOXY-5-NONYLBENZOPHENONE OXIME (LIX 65N)

ABSTRACT

Mechanistic studies including equilibrium and kinetic aspects of palladium extraction from acidic chloride media with 2-hydroxy-5-nonylbenzophenone oxime (LIX 65N) in chloroform solution are reported. The extracted species was established to be PdL, and the extraction equilibrium constant K Tor the reaction:

Pd²+2HL(o)2PdL²(o)+2H+ was found to be 10 ^16.30The homogeneous chemical reaction PdCl₃+HLPdCl₂-L^minusH+ Cl^minus was established as The rate-determining step of the overall.reaction having a rate constant of 3.74x10 M-1s.     

EXTRACTION OF Ni(II) BY 5,8-DIETHYL-7-HYDROXY-DODECAN-6-OXIME DISSOLVED IN TOLUENE

ABSTRACT

The extraction of Ni(II) from 1.0 mol.dm^-3NaNO₃, by 5,8-diethyl-7-hydroxydodecan-6-oxime (DEHO), the active component of LIX 63, dissolved in toluene has been studied by distribution methods. The experimental data in the form of log D = f(pH) at several DEHO concentrations treated both graphically by curve fitting methods as well as numerically by means of the LETAGROP-DISTR program, may be explained assuming the formation of the metal species indicated in Table 1.     

INTERFACIAL ADSORPTION OF 2-HYDROXY-5-NONYLBENZOPHENONE OXIME IN STATIC AND VIGOROUSLY STIRRED DISTRIBUTION SYSTEMS

ABSTRACT

The interfacial adsorption of 2-hydroxy-5-nonylbenzo-phenone oxime (LIX65N) at a n-heptane/water interphase was examined under static and vigorously stirred conditions, varying the aqueous pH from 2 to 12. In static systems, the pH and the concentration dependences of the interfacial tension were analysed on the basis of the Gibbs equation. The acid dissociation equilibrium at the interface was evaluated. In vigorously stirred systems, the interfacial adsorption was observed as a reversible, reproducible decrease of the organic phase concentration in response to stirring. A Langmuir isotherm was applicable for the adsorption of neutral LIX65N in acidic condition. The greater adsorption of the anionic form of LIX65N occurring in alkaline condition required an alternative isotherm.     

SYNERGIC EXTRACTION OF Ni(II) BY MIXTURES OF 5,8-DIETHYL-7-HYDROYDODECAN-6-OXIME AND n-DODECANOIC ACID IN TOLUENE

The extraction of Ni(II) from nitrate medium by mixtures of the reagents 5,8-diethyl-7-hydroxydodecan-6-oxime (HL) and n-dode-canoic acid (HA) dissolved in toluene has been studied by distribution methods. The experimental data, treated by graphical methods as well as numerically with the LETAGROP-DISTR program, can be explained assuming the formation in the organic phase of the species NiNO³ L³ H², NiL² H²A² and NiL² HA. Equilibrium extraction constants are given.     

SOLVENT EXTRACTION EQUILIBRIUM OF NICKEL FROM AMMONIACAL SOLUTIONS BY LIX 64N

Equilibrium data for the solvent extraction of nickel from amraoniacal solutions by LIX 64N (10 vol%) dissolved in kerosene (15% aromatic content) are reported. The effect of NH3/aq) concentration, LIX 64N concentration, pH and temperature are shown. The stoichiometry of the Ni-active oxime in LIX 64N complex was ascertained by spectrophotometry studies. A mathematical mechanistic model was developed for the prediction of extraction distribution coefficients as a function of pH. The model predicts more accurate results at high pH values, as could be expected taking into consideration the assumptions made in developing the model.     

EXTRACTION OF COPPER BY LIX65N IN A VESSEL AND A MULTI-STAGE COLUMN UNDER STIRRED CONDITIONS

ABSTRACT

The extraction experiments of copper from aqueous solutions of copper sulfate by LIX65N-kerosene solutions were carried out at 25^°C in liquid-liquid dispersions. Both reaction rates of the forward and backward extractions were obtained in a stirred vessel, being combined with the equilibrium data. For a multistage column in continuous operation, the holdup data of the dispersed organic phase were correlated with the stirring speed, flow rates and LIX65N concentration. It was found that the extracted fraction of copper in the multi-stage column can be predicted from a stage-to-stage calculation using the extraction kinetics and the holdup obtained in the present work.     

SOLVENT EXTRACTION OF COPPER(II), NICKEL(II), AND COBALT(II) FROM SODIUM CHLORIDE SOLUTIONS BY OCTANAL OXIME

The extraction of divalent copper, nickel, and cobalt from sodium chloride solutions with octanal oxime (OCOX) was found to proceed by the following reaction:

The association of octanal oxime in toluene was taken into account in the modelling of the extraction reaction, and the formation constants for dimers and trimers were calculated using vapour-pressure osmometry. Stability constants for the formation of aqueous copper-chloro species were also calculated.     

瑞尼镍催化氢化4-(4-甲氧基苯基)-3-丁烯-2-酮选择性与pH值的关系

4 (4 甲氧基苯基 ) 3 丁烯 2 酮的乙醇溶液在不同的pH值条件下用瑞尼镍催化氢化 ,产物用气相色谱分析 ,研究瑞尼镍的催化选择性与反应介质pH值的关系。实验结果表明 ,在碱性和酸性条件下 ,瑞尼镍的氢化选择性降低 ,在中性条件下 ,瑞尼镍的选择性大于 99%     

THE EXTRACTION BY N.N'TETRABUTYLGLUTARAMIDES II. EXTRACTION OF U(VI), Pu(IV) AND SOME FISSION PRODUCTS

The extraction of U(VI) and Pu(IV) from aqueous nitrate solutions by N,N'-tetrabutylglutaramide (TBGA) has been investigated. At low acidities, the extraction takes place via the formation of respectively UO₂(NO₃)₂. TBGA and Pu(NO₃)₄. TBGA which seem to be linked with additionnal molecules of TBGA in the second coordination sphere of the metal. When the saturation of TBGA by UO₂ ²⁺solutions is reached, the uranyl complex reorganizes to give a polymer (UO₂(NO₃)₂ TBGA)_x.

At high acidities, the anionic complexes : [UO₂(NO₃)₃, ^?] [HTBGA⁺] and probably [HPu(NO₃)₆?] [HTBGA+] are observed.     

EXTRACTION AND SEPARATION OF ZIRCONIUM(IV) WITH 3-HYDROXY-2-METHYL-1-PHENYL-4-PYRIDONE

ABSTRACT The extraction of zirconium(IV) from aqueous hydrochloric, sulphuric and perchloric acid solutions with 3-hydroxy-2-methyl--1-phenyl-4-pyridone (HX) dissolved in chloroform is described. Perchlorate and thiocyanate ions show a synergistic effect on zirconium extraction with HX. The synergistic effect of thiocyanate is stronger than the effect of perchlorate.

The composition of the extracted zirconium(IV) complexes is studied and a simple and rapid method for the separation of zirconium from niobium is described.     

氢氧化镍超微粉的制备研究及微观结构分析

采用沉淀转化法制备了氢氧化镍超微粉 ,并对表面活性剂的浓度、pH值及转化温度等实验参数对氢氧化镍粉末组成和结构的影响作了较细致的研究。实验结果表明 :当转化温度为 60℃ ,表面活性剂浓度为 15ml·L- 1 ,pH值为 11.0～ 12 .0时 ,所得样品为球形 ,粒径约 2 0 0nm左右     

THE BEHAVIOUR-STRUCTURE RELATIONS IN THE EXTRACTION OF COBALT(II), NICKEL(II), COPPER(II) AND CALCIUM(II) BY KONOACIDIC ORGANOPHOSPHORUS EXTRACTANTS

The reaction stoichiometrics were studied in the extraction of Co(II), Ni(II), Cu(II) and Ca(II) by n-octyl, 1-methylheptyl and 2-ethylhexyl hydrogen styrylphosphonates and di-2-ethylhexylphosphoric acid and 2-ethylhexyl hydrogen 2-ethylhexylphosphonate. The ultraviolet-visible and infrared spectra were recorded for these extractants and their complexes with the above metals. Based on the experimental data, an empirical relationship was established between the structure of the extractants and the extracting behavior: pH_½ = ApKa + Bν_p=0 - c where pKa and ν_p=0 are the acid dissociation constant of the extractants and the characteristic frequency of infrared absorption for the P=0 group, respectively. The values of A, B and C depend on the extracted metals. The analysis of the relationship between the steric effect of substituting groups and extracting power seems to indicate that the steric effect has been implied in the coefficients A, B and C.     

EXTRACTION AND COMPLEX FORMATION OF PLUTONIUM(IV) WITH 1-PHENYL-2-METHYL-3-HYDROXY-4-PYRIDONE

Abstract

At a ionic strength of 1.0 and mineral acid concentrations of 0.1 to 1M, l-phenyl-2-methyl-3-hydroxy-4-pyridone (HX, 0.001 to 0.01M in chloroform) extracts plutonium(IV) effectively from nitrate solutions, somewhat less effectively from perchlorate solutions and markedly less effectively from chloride solutions. The extractant distributes between the phases in a monomeric form, as an undisso-ciated molecule and a cationic species. The stoichiometries of the complexes extracted from the respective ionic media are PuX₂(NO₃)₂, PuX₃(Clo₄)₂HX and PuX₂(Clo₄)₂.HX, and PuX₂Cl₂.     

THERMODYNAMIC STUDY OF THE EXTRACTION OF INDIUM(III) AND CADMIUM(II) BY CYANEX 301 FROM CONCENTRATED HCl MEDIA

ABSTRACT

The distribution equilibria of In(III) and Cd(II) between aqueous HCl solutions and kerosene containing Cyanex 301 (bis(2,4,4-trimethylpentyl) dithiophosphinic acid denoted hereafter HL) and 10 % (V/V) of n-decanol are investigated. In(III) and Cd(II) are extracted as InL₃ and CdL₂, respectively and a physico-chemical model is proposed for modelling the distribution data. In the final part of the paper, this, model is used to discuss the optimal conditions for separating indium and cadmium, previously co-extracted with Cyanex 301, by stripping in HCl media.     

IMPREGNATED RESINS CONTAINING DI-(2-ETHYLHEXYL) THIOPHOSPHORIC ACID FOR THE EXTRACTION OF PALLADIUM(II). I. PREPARATION AND STUDY OF THE RETENTION AND DISTRIBUTION OF THE EXTRACTANT ON THE RESIN.

ABSTRACT

Solvent impregnated resins containing di-(2-ethylhexyl) thiophosphoric acid(DEHTPA) were prepared by direct adsorption of the extractant onto Amberlite XAD2 using a dry impregnation method. The impregnated resins were characterized by means of potentiometnc titrations and specific surface area measurements, and a new method to determine DEHTPA content in the resin based on surface area measurements, is proposed. The distribution of DEHTPA between the aqueous phase and the resin phase was studied, and the data obtained     

EXTRACTION OF Ce(III) AND Eu(III) BY NITROBENZENE SOLUTIONS OF BIS-1,2-DICARBOLLYLCOBALTATE IN THE PRESENCE OF 18-CROWN-6

ABSTRACT

The extraction of Ce(III) and Eu(III) by nitrobenzene solutions of bis-l,2-dicarbollylcobaltate anions in the presence of 18-crown-6 from aqueous solutions of nitric acid has been investigated. Distribution ratios, the protonization and exchange extraction constants for the investigated systems has been determined. The calculated values of distribution ratios D have been compared with experimental ones.     

THE EXTRACTION OF NEPTUNIUM(V) BY METHYLTRIOCTYLAMMONIUM CHLORIDE AND 1-PHENYL-3-METHYL-4-BENZOYL-5-PYRAZOLONE

The synergistic effect of methyltrioctylammonium chloride (QCI) on the extraction of Np(V) by 1-phenyl-3-methyl-4-benzoyl-pyrazolone(HP) in benzene is studied over the pH range 2-6. This system extracts Np(V) better than any previously reported. The interaction of the extractants and monomer-dimer equilibria affect the distribution behavior of Np(V) in a complicated manner. Analysis of the results suggests that NpO₂ ⁺ (M⁺) is extracted as mixed dimers, (QMP₂QCl)_o and (QMP₂QP)_o.     

SOLVENT EXTRACTION OF METALS WITH 4-DINITROBENZOYL-2, 4-DIHYDRO-5-METHYL-2-PHENYL-3H-PYRAZOL-3-ONE (DMPP)

ABSTRACT

The mechanism of the extraction of copper (II), nickel (II), cobalt (II) and thorium (IV) from aqueous buffer media with 4-dinitrobenzoyl1-2, 4-dihydro-5-methyl-2-phenyl-311-pyrazol-3-one (DMPP) in benzene has been investigated. The values of log K^*where K^*refers to the extraction equilibrium Mn⁺+-nHL ? MD_n+ nH⁺are Cu(II)& lpar; + 0.3), Co(II) (?6.65), Ni(II) (?5.04) and Th(IV) ( + 6.1). Solid complexes synthesized have the composition CuL₂· 2H₂O, NiL₂· 2H₂O and ThL₄respectively (L = anion of the ligand). DMPP seems to be superior to the corresponding 4-benzoyland 4-nitrobenzoyl derivatives of 2,4-dihydro-5-methyl-2-phenyl1-3 H-pyrazol1-3-one (MPP) and also better than thenoyltrifluoroacetone, the popularly employed fluorinated β-dike tone in the system investigated.