Bifunctional Extractants Research Articles

Evidence of Supramolecular Origin of Selectivity in Solvent Extraction of Bifunctional Amidophosphonate Extractants with Different Configurations

ABSTRACT Extraction mechanisms of two bifunctional extractants which differ only by the grafting of an alkyl chain between their two functions were investigated at molecular and supramolecular scales to investigate the origin of their very different separation factors toward uranium and zirconium. Investigation of the complex structure with spectroscopic analysis (Fourier Transform Infra-Red (FTIR), ElectroSpray Ionization Mass Spectroscopy (ESI-MS) and Extended X-Ray Absorption Fine Structure (EXAFS)) demonstrated that alkylation does not affect the chelation mechanism of uranium and zirconium. Stoichiometries of complexes remain identical for both extractants: UO2L2(NO3)2 and zirconium polynuclear complexes are formed after extraction into the organic phase. The origin of selectivity was therefore investigated by considering the supramolecular self-assembly of the two bifunctional molecules. Small-Angle X ray and Neutrons Scattering (SAXS and SANS) showed that the highest separation factors between U and Zr are obtained when smaller aggregates are formed. The results of this study therefore suggests that the selectivity is controlled by the supramolecular self-assembly of the two extractant molecules. Thanks to a smaller packing parameter, the non-alkylated molecule forms bigger aggregates analogous to reverse micelles that can extract additional polar species in their polar core through a solubilization effect, thus decreasing the separation factor between uranium and zirconium.

Aggregation of Bifunctional Extractants Used for Uranium(VI) Separation.

DEHCNPB (butyl-N,N-di(2-ethylhexyl)carbamoyl-nonylphosphonate) is an amido-phosphonic acid that has remarkable properties for the separation of uranium from wet phosphoric acid. Despite previous studies, a detailed description of the DEHCNPB organic solutions at the supramolecular and molecular scales is missing. In the present work, we use classical Molecular Dynamics (MD) combined with SANS and SAXS experimental data in order to describe the aggregation of the bifunctional extractant DEHCNPB as well as the speciation of uranium(VI) in such systems. We provide a fine description of the molecular species in the organic solution and of the interactions within the aggregates formed, shedding light on solvent extraction mechanisms. Without uranium, the organic phase is highly composed of dimers and trimers H-bonded through phosphonate functions and without water molecules. With uranium, two to three extractant molecules coordinate directly the uranyl cation by their phosphonate groups. Uranyl is not fully dehydrated in this organic solution, and the amide groups of the extractants are found to form H-bonds with the water molecules bound to uranyl. These H-bond networks around the metallic cation stabilize the complexes and facilitate the extraction. These results underline the importance of considering weak interactions in the understanding of extraction processes and demonstrate how molecular simulations provide essential insights into such complex organic phase chemistry with a high number of species.

SYNTHESIS AND PROPERTIES OF METAL-COMPLEX CATALYSTS BASED ON OIL METALLOPORPHYRINS

The study of the properties and use of natural metalloporphyrins in the development of new highly selective methods for the oxygenation of hydrocarbons at moderate temperatures is an urgent problem. The present work is devoted to the extraction of metalloporphyrins from oil residues and the creation on their basis of effective catalytic systems for the oxidation of alkenes. The separation of metalloporphyrins from oil residues was carried out using new bifunctional organic extractants having the nature of keto-alcohols and providing a greater degree of extraction of porphyrins in comparison with the known traditionally used extractants. The results of a study of a number of new bifunctional organic reagents as extractants for the selective extraction of oil porphyrins from asphaltenes are presented, their spectral characteristics are studied, the dependence of the degree of extraction on the mass ratio of the extractant and the crude oil is revealed. The best results were obtained with a mass ratio of 1:30. The isolated mixture of metalloporphyrins is first subjected to demetallization with hydrochloric acid (pH=1–2), turning into a mixture of porphyrins, then, to obtain individual metal porphyrin complexes, the required transition metal ions are introduced into the porphyrin ring by treating the mixture with these metal salts. It was shown that the yield of synthesized oil porphyrins is 42–85 %, depending on the nature of the metal. The composition and structure of the synthesized oil metalloporphyrins containing iron, cobalt, nickel, manganese are established by modern methods of physico-chemical analysis. The catalytic properties of synthesized metalloporphyrins in the epoxidation of unsaturated alkenes have been investigated. Their dioxide adducts were obtained, and a mechanism was proposed for the oxidation of alkenes with the formation of oxinoid structures as a result of the decomposition of the oxygen complexes of metal porphyrins

Separation of palladium and europium upon extraction with phosphorylated calix[4]- and thiacalix[4]arenes from nitric acid and carbonate solutions

Separate and concurrent extraction of palladium and europium from nitric acid and carbonate solutions with calix[4]- and thiacalix[4]arenes, their phosphorylated derivatives, and mixtures have been carried out. Charge state of sulfur and oxygen donor atoms in the extractants have been studied by XPS, XES, and quantum chemical calculations. It has been experimentally confirmed that the electronic structure of substituents at PO group has no effect of on the charge state of sulfur atoms in phosphorylated thiacalixarenes and assumption on the possible electronic effect of bridging sulfur atoms on the charge state of phosphoryl oxygen in bifunctional extractants has been made. These results substantiate the method of combined extraction of Pd and Eu from nitric acid solutions and their separation with factor 2 × 103 upon carbonate back extraction of europium and are of interest for simplified (Purex) and promising (Carbex) processes.

Extraction of palladium with thiacalix[4]arenes from nitric acid nitrate-nitrite solutions

Calix[4]arene 1, thiacalix[4]arenes 2(LH4), and calix[4]arenethioether 3 were compared in palladium extraction from nitric acid solutions; DPd for 2 was shown to be 2–3 orders of magnitude larger than for 1 at pH > 3 (comparable with 3) because of cation-exchange and coordination extraction of palladium. It was shown by extraction methods and IR spectroscopy that thiacalixarenes 2 extract complex species [PdnLmH4 − 2n] (m = 1, n = 1 and 2) and [(PdA2)nLmH4] (A = m = 1, n = 1–4) from nitric acid solutions at pH 3. Extraction constants for these palladium species that satisfactorily describe experimental data were calculated. As distinct from 3, thiacalixarenes 2 are promising for the combined extraction of palladium and silver from alkaline solutions and the selective extraction of fission palladium from nitric acid solutions. Phosphorylated at the upper rim thiacalixarenes 2 can be considered as bifunctional extractants for the separation of fission radionuclides.

Recovery of rare earth elements from simulated fluorescent powder using bifunctional ionic liquid extractants (Bif‐ILEs)

AbstractBACKGROUND:Numerous high purity ammonium‐type ionic liquid extractants have been prepared for engineering purposes. Bifunctional ionic liquid extractants (Bif‐ILEs) have been widely applied to separate and extract rare earths and metal ions with high extraction efficiencies and selectivities. In the present study, new Bif‐ILEs [A336][P204] and [A336][P507] have been used to extract rare earths from a simulated solution of a fluorescent powder in a high concentration of Al(NO3)3.RESULTS:Bif‐ILEs were prepared from Aliquat336 (A336) and the commercial organophosphorus acid extractants, P204 and P507. These extractants [A336][P204] and [A336][P507] have similar characteristics to neutral organophosphorus extractants. When these Bif‐ILEs were used to extract RE(III) from a simulated waste fluorescent powder system a third phase appeared which could be eliminated by the addition of 10% isopropanol modifier. The coexisting Al2O3in the fluorescent powder was changed to a salting‐out agent (Al(NO3)3) in the extraction process and promoted the extraction efficiency of RE(III). Using a countercurrent extraction process at a phase ratioVo:Vw= 4:1 and pH = 0.56, the RE(III) recovery reached 95.2% in 5–7 stages. Finally, the extractabilities of these bifunctional extractants were compared with the neutral organophosphorus extractants P350, TBP and Cyanex923 at different concentrations, initial pHs and temperatures.CONCLUSIONS:By comparison with other neutral organophosphorus extractants, Bif‐ILEs [A336][P204] and [A336][P507] can be considered efficient potential extractants for separating and recycling REEs and Al2O3from waste fluorescent powder. Copyright © 2011 Society of Chemical Industry

Extraction chromatography of thorium ion by solid phase impregnated resins containing bi-functional organic extractants</p> </p>

Extraction chromatography of thorium ion by solid phase impregnated resins containing bi-functional organic extractants</p> </p>

Extraction of Copper(II) from Chloride Systems with Individual and Mixed Extractants

Extraction of copper(II) and zinc(II) from acidic chloride solutions with individual extractants, binary mixtures of two extractants and bifunctional extractants is discussed. Neutral pyridine type extractants with electron withdrawing substituents can be used for copper recovery from concentrated chloride solutions. Stripping can be accomplished with water. Binary mixtures containing a basic or solvating extractant and a chelating extractant permit the recovery of copper(II) and zinc(II) from acidic chloride solutions with the change from a chloride to a sulphate system. The method is also suitable for separating copper(II) from zinc(II) at the extraction, scrubbing or stripping stage. The use of ALAMINE 336 and LIX 54 is proposed when iron(III) is absent or ACORGA CLX 50 and LIX 54 when Fe(III) is present in the aqueous feed. KELEX 100 and LIX 26 can be considered as bifunctional extractants and can be used to recover both copper(II) and zinc(II) from acidic chloride solutions in the absence of iron(III) and to separate these metal ions at the extraction, scrubbing or stripping stage.

Bi-Functional Organophosphorus Extractants and Computational Modeling for Copper(II) and Zinc(II) Extraction.

Novel bi-functional extractants, which possess two phosphonic groups on both sides of the extractants, have been synthesized for the separation of Zn(II) and Cu(II). The separation properties and extractability of the novel extractants were investigated using the liquid-liquid extraction technique. These bi-functional extractants provide a high selectivity towards Zn(II) over Cu(II) compared to that of monoacidic phosphorus extractant as an analog. We discussed the extraction behavior of the bi-functional extractants with a computational modeling by means of semi-empirical molecular orbital methods. The calculation suggests that the length of the spacer is one of the decisive factors to enhance the selectivity in the bi-functional extractants. The high separation ability for the bi-functional extractants was related to the high energy difference in the heat of formation calculated by computational modeling. The computational simulation was found to be very useful for the design of novel extractants and prediction of their separation performance.

Development and Computational Modeling of Novel Bifunctional Organophosphorus Extractants for Lanthanoid Separation

Novel organophosphorus extractants, which have two functional groups in the molecular structure, have been developed for the separation of lanthanoids using the liquid-liquid extraction technique. The separation efficiency and extractability of the novel extractants were investigated for nine lanthanoids. These bifunctional extractants have an extremely high extractability to all the lanthanoids compared to those of commercially available organophosphorus extractants. Two isomers having an identical chemical formulation show significantly different behaviors in lanthanoid extraction. This means that the extraction and separation abilities are quite sensitive to the structure of the spacer connecting the two functional groups. We also discuss the experimental results with a computational modeling by means of molecular mechanics and semiempirical molecular orbital methods. The novel molecular mechanics (MM) calculation program MOMEC enables us to analyze the stable conformation of a series of lanthanoid complexes. The calculation suggests that the structural effect of the spacer is one of the decisive factors for enhancing selectivity and extractability in lanthanoid extraction.

Solvent extracted and extraction chromatographically adsorbed complexes of bifunctional extractants with f-elements

The IR spectra of the solvent extracted and extraction chromatographically adsorbed complexes of HNO3, Nd(III), Th(IV) and U(VI) with bifunctional extractants dihexyl N,N-diethylcarbamoylmethylophosphonate (CMP) and octyl (phenyl)-N,N-diisobutylcarbamoyl-methylphosphine oxide (CMPO) have been recorded. The shifts in the P=0 and C=0 streching frequencies have been interpreted. The nitrate ions bound with metal ions were found to be bidentate. The nature of binding of the extractant to the metal ions in the solvent extracted and extraction chromatographically adsorbed complexes were found to be similar.

DILUENT EFFECTS IN THE EXTRACTION OF AMINE FROM NITRIC ACID SOLUTIONS BY SELECTED CARBAMOYLPHOSPHORYL EXTRACTANTS AND RELATED MONOFUNCTIONAL COMPOUNDS*

ABSTRACT The extraction of Am(III) from nitric acid solutions by a series of bifunctional extractants containing the carbamoylphosphoryl moiety and of monofunctional extractants containing the P=O donor group, has been investigated using a number of different diluents. In some diluents, such as chloroform, dichloroethane and nitrobenzene, the existence of an apparently anomalous order of Am(III) extraction (that is higher metal extraction for lower basicity of the extractant) has been confirmed with phenyl substituted carbamoylmethylphosphine oxides. No evidence of anomalies was found in other diluents, for example carbon tetrachloride, tetrachloroethylene and o-xylene. While it seems unlikely that the “anomalous aryl strengthening” effect, recently reported in the soviet literature, can account for the extraction behavior of Am(III) by the bifunctional extractants and diluents investigated in this work, the apparent anomalies have been simply explained by strong solvation effects between the diluent and the very basic extractants.

Carbamoylmethylphosphoryl Compounds: Ch-Acidity and Basicity

Abstract Carbamoylmethylphosphoryl compounds (CMP) are used as neutral bifunctional extractants. However, little is known about acid-base properties of these compounds. We have studied CH-acidity and basicity of selected CMP, RR′P(O)CH2C(O)NEt2 with R,R′ = Alk, Alk2N, Ar, AlkO, and also H-complexes of CMP with HNO3.

Carbamoylmethylphosphoryl Compounds: Ch-Acidity and Basicity

Abstract Carbamoylmethylphosphoryl compounds (CMP) are used as neutral bifunctional extractants. However, little is known about acid-base properties of these compounds. We have studied CH-acidity and basicity of selected CMP, RR′P(O)CH2C(O)NEt2 with R,R′ = Alk, Alk2N, Ar, AlkO, and also H-complexes of CMP with HNO3.

INFRARED STUDIES OF BIFUNCTIONAL EXTRACTANTS*

ABSTRACT The infrared spectra of a series of neutral bifunctional extractants were examined. The carbonyl and phosphoryl stretching regions were monitored for changes as nitric or hydrocloric acid was extracted and as Nd(III) or Sm(III) was extracted. It was found that the phosphoryl group is the primary site of extraction as was predicted from solvent extraction measurements. Upon heavy loading of the metal ion in the organic phase, the extractant OφD(iB)CMP0 (octyl(phenyl)-diisobutylcarbamoylmethylphosphine oxide) can behave as a bidentate ligand as does the analogous di-hexyl-N,N-diethylcarbamoylmethylphosphonate solid state complex. The tendency for the carbonyl oxygen to form a bond directly to the metal ion is enhanced in chloride media at low acidity. The spectra of mixtures of 0φD(iB)CMP0 with the phase modifier TBP indicate no interaction between the two extractants and TBP does not appear to be part of the primary metal-extractant complex.

VARIATIONS IN THE SOLVENT EXTRACTION BEHAVIOR OF BIFONCTIONAL PHOSPHORUS-BASED COMPOUNDS MODIFIED WITH TBP

The solvent extraction of americium from nitric acid by several modified bifunctional extractants in CCl/sub 4/ has been investigated. For all the compounds examined, addition of a modifier such as tributylphosphate (TBP) enhances distribution ratios at high aqueous acidities. The effect of the modifier at lower acidities varies depending on the basicity of the bifunctional extractant. While the most basic extractants show significantly reduced distribution ratios from lower acid solutions upon TBP addition, for the less basic compounds only slight reductions or, in some cases, even moderate increases in extraction are observed. Studies of the effect of modifier basicity on extraction behavior with modifiers fall within the range of variations observed for diluent effects with extractants of this type. Increases in high acid distribution ratios upon TBP addition to an extractant as simple as trioctylphophine oxide indicate that this modification of extraction behavior may be of general use for a wide range of neutral extractants. 21 references, 3 figures, 1 table.

APPLICATION OF LANTHANIDE INDUCED SHIFTS FOR THE DETERMINATION OF SOLUTION STRUCTURES OF METAL ION - EXTRACTANT COMPLEXES

Abstract An analysis of the induced shifts in the nuclear magnetic resonance spectra of extractants complexed to paramagnetic lanthanide ions has been carried out. The complexes of a number of monofunctional and bifunctional extractants have been examined and assigned solution structures by minimizing the differences between the observed shifts and those calculated using a computer analysis in which the potential configurations of the complexes were generated. Complexes of monofunctional extractants were calculated to have coordination geometries quite similar to those observed in related compounds by crystallographic techniques. For the bifunctional extractants, differentiation between monodentate and bidentate coordination seems possible

THE EXTRACTION OF Am(III) FROM NITRIC ACID BY OCTYL(PHENYL)-N,N-DIISOBUTYLCARBAMOYLMETHYLPHOSPHINE OXIDE - TRI-n-BUTYL PHOSPHATE MIXTURES

Abstract The extraction behavior of Am(III) from nitric acid by octy1(phenyl)-N,N-diisobutylcarbamoyl methyphosphine oxides, OØD[IB]CMPO, in the presence of tributylphosphate, TBP, has been studied using diethylbenzene, decalin, and normal aliphatic hydrocarbon diluents. Relative to ØD[IB]CMPO alone, mixtures of TBP and OØD[IB]CMPO show a slight enhancement in the extraction of Am(III) from nitric acid solution above 2 M and a moderate decrease in extraction for lower acid concentrations. The net effect of TBP addition to OØD[IB]CMPO (as well as other selected carbamoyl methylphosphoryl extractants) is a relative insensitivity of the distribution ratio of Am(III) to HNO3 concentration in the range of 0.5 M to 6 M and facilitated stripping of Am(III) with dilute acid. Since a continuous variation study of Am(III) extraction using mixtures of ØOD[IB]CMPO and TBP at a fixed total concentration revealed no evidence of a mixed complex, the TBP appears to be behaving primarily as a phase modifier The most significant benefit gained from addition of TBP to ØD[IB]CMPO is the increased metal ion loading capacity and extractant compatibility with alicyclic and aliphatic diluents. The use of TBP to overcome phase compatibility with other bifunctional extractants of the carbamoylmethylphosphoryl type and the use of other phase modifiers with ØD[IB]CMPO have also been investigated.

ChemInform Abstract: POLYAMINO ALCOHOLS AS BIFUNCTIONAL EXTRACTANTS FOR COPPER(II)

Chemischer InformationsdienstVolume 15, Issue 1 Physical Inorganic Chemistry ChemInform Abstract: POLYAMINO ALCOHOLS AS BIFUNCTIONAL EXTRACTANTS FOR COPPER(II) U. DINJUS, U. DINJUSSearch for more papers by this authorH.-H. + HOERHOLD, H.-H. + HOERHOLDSearch for more papers by this authorJ. KLEE, J. KLEESearch for more papers by this authorE. UHLIG, E. UHLIGSearch for more papers by this author U. DINJUS, U. DINJUSSearch for more papers by this authorH.-H. + HOERHOLD, H.-H. + HOERHOLDSearch for more papers by this authorJ. KLEE, J. KLEESearch for more papers by this authorE. UHLIG, E. UHLIGSearch for more papers by this author First published: January 3, 1984 https://doi.org/10.1002/chin.198401019Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume15, Issue1January 3, 1984 RelatedInformation

Approaches Toward Synthesizing Novel Extractant Systems: Polymeric Bifunctional Extractants with Synergistic Possibilities

Abstract The synthesis of a monoarylphosphinic acid-diarylphosphine oxide extractant system supported on macroporous polystyrene beads is reported. The bifunctional resin was used in separate zinc and copper(I1) ion extraction studies. Results wth both metals show an excellent extent of extraction under low loading conditions and solution pH of 1–2; at equivalent meta1:resin concentrations, the resin absorbs 50% of the metalin solution. Comparison with lower absorption values reported in the literature for similar systems suggests the possibility of a synergisticextraction due to cooperation between the acid and oxide moieties.