AGGREGATION OF P,P' -DI( 2-ETHYLHEXYL) METHANEDIPHOSPHONIC ACID AND ITS Fe(III) COMPLEXES ∗

ABSTRACT

The aggregation of P,P' -di( 2-ethylhexyl) methanediphosphonic acid, H2DEH[ MDP] dissolved in deuterated toluene has been investigated by small angle neutron scattering ( SANS) The title compound was shown to exist in solution as a dimer under all conditions. Dimer formation is independent of the acidity of the aqueous solution with which the organic solution is pre-equilibrated. Solutions of H₂ DEH[ MDP] containing increasing amounts of Fe( lll) extracted from aqueous solutions in the acidity range from 0.1 to 5 M were also investigated. The SANS results confirm the tendency of H2DEH[ MDP] -Fe( III) species in aromatic diluents to form rod-like aggregates characteristic by a constant cross section and a length which increases with increasing amounts of metal in the organic phase. Particle growth is independent of the acidity of the aqueous solutions from which the metal is extracted. These results are important for understanding the chemistry underlying the solvent extraction behavior H₂DEH[ MDP] and its practical application in separation procedures.     

METAL EXTRACTION BY ALKYL SUBSTITUTED DIPHOSPHONIC ACIDS. PART 4 P,P′-DI(2-ETHYLHEXYL) BUTANEDIPHOSPHONIC ACID

ABSTRACT

As part of an ongoing investigation of the properties of dialkyl substituted diphosphonic acids as solvent extraction reagents for metal cations, we have studied the extraction of alkaline earth cations, Fe(III) and representative actinides (Am(III), U(VI) and Th(IV)) at tracer-level concentration by o-xylene solutions of P,P′-di(2-ethylhexyl) butanediphosphonic acid, H₂DEH[BuDP]. The extractant and acid dependencies of these metal ions exhibited significant differences from those of the previously investigated analogous extractants in which the two phosphonate groups are separated by a methylene or an ethylene bridge. The aggregation of H₂DEH[BuDP] was investigated in toluene at 25° C by vapor pressure osmometry. H₂DEH[BuDP] was found to exist predominantly as a trimeric species in the 0.1-0.005 molal concentration range. Osmometric measurements and infrared spectra indicate that Ca(II) is extracted into H₂DEH[BuDP] solutions with little disruption of the structure of the extractant. Iron(III) causes significant deprotonation of the ligand and dramatically changes the apparent aggregation number. A comparison of the extraction of Ca(II), Am(III) and Fe(III) by H₂DEH[BuDP] with data obtained using bis(2-ethylhexyl) phosphoric acid (HDEHP) or 2-ethylhexyl 2-ethylhexylphosphonic acid (HEH[EHP]) as the extractant indicates that H₂DEH[BuDP] has characteristics similar to these monofunctional analogs. Infrared spectra of the Ca(II) and Fe(III) salts of H₂DEH[BuDP] show a shift of both v_asym (POO?) and v_sym (POO?) to lower frequencies relative to their values in the sodium salt. This indicates a symmetrical interaction between the metal ion and the phosphonate groups through chelate and/or bridging interactions.     

SYNERGISM IN THE EXTRACTION OF ZINC(II)AND CADMIUM(II) WITH SOME LOWER FATTY ACIDS IN THE PRESENCE OF AMINES AND THEIR SEPARATIONS∗

Abstract

Synergism in the extraction of Zn(Il) and Cd(II)with chloroform solution of propionic, butyric and valeric acids in the presence of n-butylamine, dibutylamine, tributylamine, β-picoline, pyridine and quinoline is reported The effect of various parameters affecting extractions has been investigated The compositions of synergistic adduct extracted into the organic phase have been proposed on the basis of slope analysis method. In general the species have been represented as MA2.2HA.B (aliphatic amine system and MA₂.2HA.2B (heterocyclic amine system), where M = zn(Il)/CdII), HA = acid and B = amine. On the basis of extraction constant (K_ex) values the relative effectiveness of different amines as synergists has been compared. Based on the extraction data some separations of metal ions have also been reported with fairly high separation factor (β).     

THE EXTRACTION OF SELECTED ACTINIDES IN THE ( III) (IV) AND ( VI) OXIDATION STATES FROM HYDROCHLORIC ACID BY Oπ D( iB) CMPO: THE TRUEX-CHLORIDE PROCESS∗

The extraction of tetravalent Th, Np, and Pu and hexavalent U from hydrochloric acid was studied using octyl(phenyl)-N,N-diiso-butylcarbamoylmethylphosphine oxides, 0π D(iB)CMP0 or CMPO, dissolved in tetrachloroethylene (TCE). A 0·5 MCMPO solution in TCE was found to be an extremely effective extractant for the tetravalent actinides and U(VI) from moderate to concentrated HC1. Extractant dependencies of the distribution ratios of Th(IV), U(VI), and Pu(IV) were 3rd, 2nd, and 3rd power, respectively, indicating the following species: ThCl₄’3CMPO, UO₂Cl₂2CMP0, and PuCl₄»3CMPO. The distribution ratios of a variety of non-actinide elements, including selected alkali, alkaline earths, Al, transition and post-transition metal ions were also measured from 2 Mand 6 M_ HC1. Based on the distribution ratios of tri-, tetra-, and hexavalent actinides from chloride media, a generic actinide extraction/recovery process was developed for the removal of actinides from chloride salt wastes. The process is called TRUEX-Chloride.     

EFFECT OF SELECTED β-DIKETONES ON THE SYNERGICEXTRACTION OF COBALT(II) BY TRIPHENYL-PHOSPHINE OXIDE IN BENZENE

Abstract

Synergic extraction of Co(ll) by thenoyltrifluoroacetone (HTTA), Pivaroyltrilluoioacetone (HPvTA) or hexafiuoroacetylacetone (HHFA) mixed with triphenyiphosphine oxide (ph₃PO) in benzene from perchlorate media has been investigated. It ’ was found that in all the systems studied, Co(ll) is synergistically extracted as CoL₂.ph₃PO, where L stands for the different chelating ligands. The obtained equilibrum constants for the chelating and adduct systems indicated that: i- the weaker the acidity of the chelating ligand, the higher the overall aqueous phase formation constant of the metal chelate (β₂ ), ii- the sequence of the extraction constants (K_2,1 ) and the organic phase formation constants for the adduct ( β_2,1) as related to the chelating ligands is TTA> HFA > PvTA, iii- the stability of the adduct is related to both the structure and the pK_avalues of the chelating ligands.     

THE EXTRACTION OF CATIONIC RUTHENIUM COMPLEXES FROM AQUEOUS MEDIA BY α-TIN(IV) HYDROGEN PHOSPHATE

ABSTRACT

The ruthenium species [Ru(NH₃)₆]³⁺ was adsorbed by the surface of (α-Sn(HPO₄)₂.2H₂O [SnP]) α-tin(IV) hydrogen phosphate. The ruthenium(II)-containing cation [Ru(NH₃)₆]²⁺, however, has been directly intercalated into (SnP). Since the corresponding ruthenium(III) complex cation was not so intercalated, a new self-catalysed intercalation mechanism involving labile ammonia ligands from the ruthenium(II) has been proposed. At high loadings, guest ruthenium(II) species were oxidised to ruthenium(III).     

STUDIES ON THE RELATIONSHIP BETWEEN THE NETWORK STRUCTURE AND THE MECHANICAL PROPERTIES OF RUBBER VULCANIZATES (H) THE REINFORCEMENT OF ELASTOMERS BY CARBON BLACK FILLERS AND ITS CHARACTERIZATION

A satisfactory account of reinforcement of rubber through the application of the theory of elasticity forits vulcanizates with carbon black fillers has been obtained. A statistical theory of reinforcement by carbonblack fillers and its characterization was developed. Three methods for     

THE SYNERGISTIC SOLVENT EXTRACTION OF RADIUM FROM ALKALINE NITRATE MEDIA BY DICYCLOHEXANO-21-CROWN-7 COMBINED WITH 2-METHYL-2-HEPTYL NONANOIC ACID EQUtUBRIUM REACTIONS AND METAL ION COMPETITION∗

The equilibria in the solvent extraction of radium from aqueous sodium nitrate/sodium hydroxide solutions by toluene solutions of dicyclohexano-21-crown-7 (DC21C7). 2-methyl-2-heptylnonanioc acid (HMHN). and mixtures of the two reagents are examined. The mixed reagents are synergistic in the extraction of radium and selective for radium over other alkali and alkaline earth elements. The dependencies of the extraction on pH and reagent concentration were utilized in computer modeling to estimate the stochiometry of the extracted complexes and equilibria involved the extraction. Three organic-phase species were identified in the extraction under basic (pH 11-13) conditions. With A = MHN^?. B = DC21C7 and assuming NaA is a 10-fold aggregate they are. RaA₂B.NaA. Log K = 3.57: RaA NaA. Log K = 0.99: and B 2NaA. Log K = ? 0.41. The effect of the presence of various concentrations of sodium     

COBALT–NICKEL SEPARATION: THE EXTRACTION OF COBALT(II) AND NICKEL(II) WITH BIS(2-ETHYLHEXYL) PHOSPHINIC ACID (PIA-8) IN TOLUENE

The extraction behaviour of cobalt(II) and nickel(II) from sulfate solutions with bis(2-ethylhexyl) phosphinic acid (PIA-8) in toluene has been studied. Quantitative extraction of Co(II) was observed at pH 5.0–5.9 while that of Ni(II) at pH 6.8–7.0 with 0.03 M PIA-8 in toluene. The difference in pH_0.5 for Co(II) and Ni(II) was 1.9. The stoichiometry of the extracted species were determined by slope analysis method. The extraction reaction proceeds by cation exchange mechanism and the extracted species were Co · R₂(HR)₂ and Ni · R₂ · 2(HR)₂. Temperature dependance of the extraction equilibrium constants were determined to estimate the apparent thermodynamic functions (ΔG, ΔS and ΔH). The method was used for separation of cobalt(II) and nickel(II). Cobalt(II) was separated from nickel even at 1:20 (Co:Ni) ratio. The separation of cobalt(II) from nickel(II) was favoured with the increase in temperature.     

THE SWELLING BEHAVIOR OF (W/O)/W LIQUID SURFACTANT MEMBRANE (Ⅰ) ADSORPTION OF SURFACTANT AT THE INTERFACE AND THE SWELLING CAUSED BY EMULSIFICATION

The concept of effective concentration of surfaetant in membrane phase has been proposed,considering the high ad-sorption density of the surfactant at the droplet interfaces in LSM system.The effective concentration of surfactant,C_2,can be estimated by Eq.(7)—(9).The swelling caused by emulsification during the initial dispersion process was investigated.The swelling rate wasmeasured by a density method.A model for estimating the“Emulsification”swelling rate,F_(se),has been proposed,basedon a mechanism of swelling due to the entrainment of water resulted from the interracial turbulence and emulsification inthe initial dispersion process.It has been found that Eq.(26)gives excellent fit to the experimental data of Fujinawa,etal.and of the authors.     

EXTRACTION OF AMERICIUM(III) FROM CHLORIDE MEDIA BY OCTYL(PHENYL)-N,N-DIISOBUTYLCARBAMOYLMETHYLPHOSPHINE OXIDE∗

The extraction of Am(III) from chloride media was studied using octyl(phenyl)-N,N-diisobutylcarbamoylmethylphosphine oxide, Oπ D(iB)CMPO or CMPO, dissolved in tetrachloroethylene. Although the extraction of Am(III) by 0πD(iB)CMPO is many orders of magnitude weaker from chloride than nitrate media, the rapid Increase in the mean activity of chloride in HC1 and in most soluble chloride salts with concentration makes extraction from moderate to concentrated hydrochloric acid and/or concentrated Li, Mg, Ca, and Al chloride salt solutions practical. The stoichiometry of the extractable chloro complex was established by extractant dependency and loading experiments and found to be AmCl₃»3CMPO. Hydrochloric acid appears to be associated with the complex when extraction takes place at high HC1 concentrations. The mode of coordination of OπD(iB)CMPO to AmCl₃appears to be bidentate in marked constrast to its behavior in the corresponding nitrate system.     

KINETIC MODELING OF HYDROISOMERIZATION OF C\-8AROMATICS(Ⅰ)MODELING AND ESTIMATION OF RELATIVE RATE CONSTANTS BY THE WEI-PRATER METHOD

1 Introduetlon To date,most kinetie investigations ofC一aromaties hydroisomerization over bifunetionaleatalysts have been eoneerned with reaetjon meehanisms.R6bsehl巨ger et al.[,]studied thehydroisomerization kineties under sPecifie eonditions,and ProPose…     

EXTRACTION OF NEPTUNIUM AND PLUTONIUM NITRATES WITH n-OCTYL(PHENYL)-N,N-DIISOBUTYL-CARBAMOYLMETHYLPHOSPHINE OXIDE∗

Distribution equilibria of Np and Pu in various valence states and stripping of Np(V) were studied in a system involving 0.20 M n-octyl(phenyl)-N,N-diisobutylcarbamoylmethylphosphine oxide + 1.2 M tributyl phosphate in dodecane as a solvent. Np(V) is weakly extractable at <2 M nitric acid but more effectively extractable at >3 M nitric acid, due to the disproportionation of Np(V) to Np(IV) and Np(VI). Addition of nitrous acid to solutions containing Np(V) increases the over-all extractabllity of Np, due to its partial oxidation to Np(VI). This is also the case In the presence of oxalic acid, both at room temperature and at 40^°C. Both Np(IV) and Np(VI) are highly extractable, but the reduction of Np(V,VI) to Np(IV) is slow even with a reductant as strong as sodium formaldehyde sulfoxylate. Pu(IV) is highly extractable and its reduction to Pu(III) with sulfoxylate Is incomplete in the two-phase system if the aqueous phase contains >0.5 M nitric acid. Extracted Np(VI) can be stripped by reduction to Np(V). The stripping rate is, however, slow with nitrous acid as the reductant at low nitric acid concentration. The reduction of Np(VI) by hydrogen peroxide is fast, but is followed by further reduction to Np(IV). Sulfurous acid reduces Np(VI) rapidly and, if no iron is present, only to Np(V), but Fe(II) induces further reduction to Np(IV).     

LIQUID-LIQUID EXTRACTION OF Pa(V) AND Zr(IV) BY MIXTURES OF A β-DIKETOHE AND A SULPHOXIDE FROM HTDROCHLORIC ACID MEDIA

The species involved in the solvent extraction of zirconium(IV) from hydrochloric acid medium by mixtures of thenoyltrifluoroacetone (HTTA) and dipentyl sulphoxlde (DPSO) in benzene as the diluent seems to be Zr(OH) ₂(TTA)₂(DPSO). Extraction of protactinium(V) by mixtures of HTTA and DPSO exhibits synergism but the extent of synergism is not very appreciable.     

EFFECT OF CHAIN LENGTH OF ALKANE-1-HYDROXY-1, 1′-METHYLDIPHOSPHONIC ACIDS ON THE IRON (III) LIQUID–LIQUID EXTRACTION

ABSTRACT

(1-Hydroxy-1-phosphonohexadecyl) phosphonic acid (HPHPA) and (1-hydroxy-1-phosphonododecyl) phosphonic acid (HPDPA) were prepared by reaction of phosphorus trichloride with palmitic and lauric acids, respectively. After purification, these products were characterized by elemental microanalysis and by IR, ¹H, ³¹P?NMR spectroscopies. In this paper, we propose a tentative assignment for the shifts of those two ligands and their specific complexes with iron (III). A spectroscopic analysis has showed that coordination of iron (III) takes place via oxygen atoms. We also measured the extraction of Fe⁺³ by HPHPA and HPDPA from [CCl₄-Octanol (v/v: 90%/10%)] solutions. The complexes formed in the organic phase may be Fe[C₁₁ H₂₃C(OH)(PO₃H)₂]Cl, 3H₂O with HPDPA and Fe[C₁₅H₃₁C(OH) (PO₃H)₂]Cl, 3H₂O with HPHPA, respectively. HPHPA as ligand exhibits a stronger extracting power for Fe³⁺ and has a more hydrophobic character than HPDPA.     

THE MASS TRANSFER BEHAVIORS OF FE(Ⅲ), CO(Ⅱ) AND NI(Ⅱ) IN SULFURIC ACID WITH CYANEX302 BY USINGMICROPOROUS HOLLOW FIBER

In this paper the mass transfer behaviors of Fe(Ⅲ), Co(Ⅱ) and Ni(Ⅱ) with Cyanex302(bis(2,4,4- trimethylpentyl)monothiophosphinic acid) from sulfate medium by using hollow fiber membrane in counter-currently circulating operation were studied. The effect of acidity in aqueous solution and the extractant concentration on the mass transfer coefficient (Kw) was discussed. The reaction mechanism of membrane extraction was considered as a false one series reaCtion and the rate controlling step was membrane resistance. When the value of Kw arrived at 1.0 × 10-6 m/s, △pH:CoFe equaled tO 6.225, and △pH:NiFe was bigger than △p HCoFe.