Diisobutylcarbamoylmethylphosphine Oxide Research Articles

Hydrofluorocarbon Diluent for CMPO Without Third Phase Formation: Extraction of Uranium(VI) and Lanthanide(III) Ions

ABSTRACT The extraction behaviors of trivalent lanthanides (La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu) and hexavalent uranium with octylphenyl(,-diisobutylcarbamoylmethyl)phosphine oxide (CMPO) from a nitric acid medium were studied using hydrofluorocarbon (1,1,1,2,2,3,4,5,5,5- decafluoropentane: HFC-43) as a nonflammable diluent. It was revealed that HFC-43 exhibits high solubility of CMPO even in the absence of tributylphosphate (TBP), which has typically been necessary to prevent third-phase formation in the conventional TRUEX process using -dodecane as a diluent. Distribution ratios have been studied as a function of aqueous HNO concentrations, CMPO concentrations, and ionic radii of lanthanide(III) ions. The stoichiometry of the extracted coordination complex was examined based on the slope analysis, and it was determined that two to three CMPO molecules are coordinated to one lanthanide or uranium ion. The feasibility of the process is indicated by the distribution ratio, which is comparable to the conventional system using -dodecane as diluent. In addition, the safety benefits of applying the nonflammable solvent HFC to the TRUEX process are also presented.

31P NMR study of the activated radioprotection mechanism of octylphenyl-N,N-diisobutylcarbamoylmethyl phosphine oxide (CMPO) and analogues.

We report a 31P NMR investigation into the activated radioprotection mechanism of octylphenyl-N,N-diisobutyl-carbamoylmethyl phosphine oxide (CMPO) and analogues in the presence of a gamma radiation field. CMPO exhibits significantly enhanced radiation resistance in the presence of high nitric acid concentrations, compared to other ligands proposed for recovery of the trivalent actinides from spent nuclear fuel. The fundamental mechanism behind this activated radioprotection has been investigated using 31P NMR and other supporting analytical techniques (GCMS and LCMS) in conjunction with systematic gamma irradiation studies, covering solvent system formulation and structural effects through the use of the CMPO analogues, dioctylphenylphospine oxide (DOPPO) and trioctylphosphine oxide (TOPO). These experiments have demonstrated that the acid-dependent, radioprotection mechanism requires a protonated phenyl-phosphine oxide motif to activate. Further, contacting these three ligand loaded organic phases with a range of mineral acids (nitric, sulfuric, hydrochloric, and perchloric acids) shows specificity for nitric acid (HNO3), and the formation of a distinct [ligand·HNO3] complex for CMPO and DOPPO, as identified by 31P NMR, and predicted by DFT calculations. We propose that this complex is capable of sequential n-dodecane excited state quenching through the conjugated aromatic functionalities on the constituent CMPO and DOPPO molecules.

Polyacrylonitrile based composite materials with extracting agents containing chemically bonded CMPO groups for separation of actinoids

Composite materials made from polyacrylonitrile binding polymer and solid extracting agents with functional groups of diphenyl-carbamoylmethylphosphine oxide bonded to a platform of calix[4]arenes and cobalt bis(dicarbollide) cluster anion were tested for application in column chromatography. They exhibited high affinity for americium, plutonium, uranium, and europium ions in nitric acid solutions. However, europium distribution isotherm in 3 M HNO3 indicated low capacity and unsatisfactory employment of the functional groups. Similar material with octyl(phenyl)-N,N′-diisobutylcarbamoylmethylphosphine oxide extracting agent had both high affinity and uptake capacity.

Inside Cover: Interfacial Complexation Reactions of Sr2+ with Octyl(phenyl)‐N,N‐diisobutylcarbamoylmethylphosphine Oxide for Understanding Its Extraction in Reprocessing Spent Nuclear Fuels (Chem. Eur. J. 47/2011)

Inside Cover: Interfacial Complexation Reactions of Sr²⁺ with Octyl(phenyl)‐<i>N</i>,<i>N</i>‐diisobutylcarbamoylmethylphosphine Oxide for Understanding Its Extraction in Reprocessing Spent Nuclear Fuels (Chem. Eur. J. 47/2011)

Interfacial Complexation Reactions of Sr2+ with Octyl(phenyl)‐N,N‐diisobutylcarbamoylmethylphosphine Oxide for Understanding Its Extraction in Reprocessing Spent Nuclear Fuels

The complexation reactions between strontium (Sr(2+)) and octyl(phenyl)-N,N-diisobutylcarbamoylmethylphosphine oxide (CMPO) were studied at the aqueous|1,2-dichloroethane (w|DCE) and aqueous|room-temperature ionic liquid (w|RTIL) microinterfaces, in order to understand its extraction in reprocessing spent nuclear fuels, remediation of environmental contamination, and potential radiological isotope feed stock for (90)Y from its isotope (90)Sr in fission byproducts. The stoichiometry (or metal to ligand ratios) and overall complexation constant (β) for these reactions at these two interfaces are described herein. Two stoichiometries at the w|DCE interface were discovered, that is, [Sr(CMPO)(2)](2+) and [Sr(CMPO)(3)](2+) with β values of 4.5×10(19) and 5.5×10(25), respectively. Only one stoichiometry was observed at the w|RTIL interface: [Sr(CMPO)(3)](2+) with β equal to 1.5×10(34). The larger complexation constant for [Sr(CMPO)(3)](2+) at the w|RTIL interface than those found at the w|DCE interface supported the previous observation of a greater distribution ratio in the aqueous-RTIL metal extraction than that in the aqueous-alkane processing. The kinetics of the reactions at the w|RTIL interface was slow. The stoichiometries at the w|DCE interface were confirmed using biphasic electrospray ionization mass spectrometry (BESI-MS) as well as direct injection of Sr(2+) and CMPO mixture by means of a "shaking flask" experiment to conventional ESI-MS.

Study of europium and selected actinides uptake on composite material CMPO-PAN

Modified CMPO-PAN production was used and the resulting composite material was tested for purposes of extraction chromatography. A commercially available extraction agent octyl(phenyl)-N,N′-diisobutylcarbamoylmethylphosphine oxide (CMPO) and polyacrylonitrile (PAN) were used. The europium uptake kinetics by composite material was studied in two different nitric acid solutions. The dependences of weight distribution coefficients (Dg) of europium, americium, plutonium, uranium, and neptunium on nitric acid concentration (0.01–5 mol L−1) in the presence of sodium nitrate (0.1 mol L−1) were determined. High Dg-values were found in 0.1–5 M nitric acid for all elements tested. Increase in europium and americium Dg-values with decrease in nitric acid concentration (bellow 0.1 mol L−1) was observed. This behaviour in diluted nitric acid solutions differs from the behaviour of the similar materials with another support. CMPO-PAN composite material was compared with commercially available TRU Resin. Dg-values of the tested elements in all solutions used were higher for CMPO-PAN than for TRU Resin. The retention of the studied elements on CMPO-PAN in hydrochloric acid was made as a screening study.

Effect of Nitric Acid Distribution on Extraction Behavior of Trivalent F‐Elements in a TRUEX System

The extraction characteristics of nitric acid with a typical TRUEX (transuranic elements extraction) solvent, the mixture of octyl(phenyl)‐N,N‐ diisobutylcarbamoylmethylphosphine oxide and tri‐n‐butyl phosphate dissolved in n‐dodecane, were studied. From the extraction results of lanthanum, the concentration of CMPO, which was not bound to metal ions or nitric acid, were estimated. The estimated concentration was appropriate in comparison with the extraction results of nitric acid. The applicability of the determined effective CMPO concentration to the formulation of the distribution equilibrium of other f‐elements was confirmed.

Leakage of Octyl(Phenyl)-N,N-Di-Isobutylcarbamoylmethylphosphine Oxide from a Macroporous Silica-Based Chelating Polymeric Adsorption Material and its Recovery by Some Selected Porous Adsorbents

The leakage behaviour of a neutral chelating agent, i.e. octyl(phenyl)- N,N-di-isobutylcarbamoylmethylphosphine oxide (CMPO), from its macroporous silica-based (CMPO/SiO2-P) extraction resin (a novel polymeric adsorption material developed in the MAREC process) and the recovery of CMPO by some selected polymer- and silica-based porous adsorbents were investigated by column operation in 0.01 M HNO3 at 25°C or 50°C. The concentration of CMPO in the effluent leaking from CMPO/SiO2-P was determined as ca. 48 ppm at 25°C and ca. 37 ppm at 50°C. The corresponding elution volumes and the amounts of CMPO leaking were 8700.9 BV/g and 239.3 mg/g at 25°C and 11 842.9 BV/g and 359.4 mg/g at 50°C, respectively. The adsorption experiment showed that a polymer-based porous material, SEPABEADS® SP-825, was capable of recovering CMPO effectively from 0.01 M HNO3. Its adsorption ability towards CMPO was considerably greater than those of macroporous silica-based SiO2-P particles, polymer-based Amberlite™ XAD-7 and activated carbon. The bed volume and the amount of CMPO adsorbed by SEPABEADS® SP-825 at the breakthrough point at 25°C were 13 549.2 BV/g and 498.7 mg/g, respectively, thereby demonstrating that SEPABEADS® SP-825 was promising for the recovery of CMPO from Am(III)- and Cm(III)-containing solutions in the MAREC process.

PREDICTION OF BREAKTHROUGH CURVE OF METAL ION ON EXTRACTION CHROMATOGRAPHIC COLUMN

ABSTRACT A mathematical model to predict the breakthrough curve of metal ion on an extraction chromatographic column was proposed. This model, which is the extension of that proposed in the previous paper (12), consists of the mass transfer equation of metal ion into a polymer gel impregnated with an extractant and the mass balance equation of chromatographic column. SDB (styrene-divinylbenzene copolymer) gels impregnated with CMP (dihexyl-N,N'-diethylcarbamoylmethylphosphonate), CMPO (octyl(phenyl)N,N'-diisobutylcarbamoylmethylphosphine oxide) and the equimolar mixture of CMP and CMPO were prepared. The column experiments for the extraction of Ce(III) from an aqueous solution containing nitrate ion were carried out. The predicted breakthrough curves of Ce(III) for the gels impregnated with CMP and the mixture of CMP and CMPO were in good agreement with the experimental ones. That for the gel impregnated with CMPO, however, overestimated the experimental data. This is due to adhesion among gel particles which is caused by the deliquescence of CMPO and not attributable to the mathematical model. These results suggest that the proposed model is applicable to the prediction of breakthrough curve and available as a design tool of extraction chromatographic column.

Partitioning of Actinides from High Level Waste of PUREX Origin Using Octylphenyl-N,N'-diisobutylcarbamoylmethyl Phosphine Oxide (CMPO)-Based Supported Liquid Membrane

The present studies deal with the application of the supported liquid membrane (SLM) technique for partitioning of actinides from high level waste of PUREX origin. The process uses a solution of octylphenyl-N,N'-diisobutylcarbamoylmethyl phosphine oxide (CMPO) in n-dodecane as a carrier with a polytetrafluoroethylene support and a mixture of citric acid, formic acid, and hydrazine hydrate as the receiving phase. The studies involve the investigation of such parameters as carrier concentration in SLM, acidity of the feed, and the feed composition. The studies indicated good transport of actinides like neptunium, americium, and plutonium across the membrane from nitric acid medium. A high concentration of uranium in the feed retards the transport of americium, suggesting the need for prior removal of uranium from the waste. The separation of actinides from uranium-lean simulated samples as well as actual high level waste has been found to be feasible using the above technique.

Degradation, Cleanup, and Reusability of Octylphenyl- N, N′-diisobutylcarbamoylmethyl Phosphine Oxide (CMPO) during Partitioning of Minor Actinides from High Level Waste (HLW) Solutions

ABSTRACT The radiolytic degradation of the extractant mixture 0.2 M octylphenyl-N,N′-diiso-butylcaibamoylmethyl phosphine oxide (CMPO) + 1.2 M tributyl phosphate in n- dodecane [to be utilized for the partitioning of minor actinides from high level waste (HLW) solutions of PUREX origin] has been investigated in contact with 3 M HNO3 or synthetic pressurized heavy water reactors (PHWR)-HLW solution under dynamic conditions. The distribution ratios of Am, Zr, Fe, and Ru with the irradiated extractant mixture at varying doses have been determined under various aqueous phase conditions and correlated with the formation of degradation products. Various cycles ofloading the extractant mixture with Am from PHWR-HLW, irradiating at a fixed gamma dose, and then primary and secondary clean-up of the solvent has been carried out to illustrate its reusability during partitioning of minor actinides from actual HLW solutions. The degradation products of CMPO have been identified by employing GC and GC-MS techniques.

Recovery of plutonium and americium from laboratory acidic waste solutions using tri- n-octylamine and octylphenyl- N- N- diisobutylcarbamoylmethylphosphine oxide

Plutonium from acidic waste solutions has been recovered quantitatively using tri- n-octylamine (TnOA) in xylene and americium using a mixture of octylphenyl- N- N- diisobutylcarbamoylmethylphosphine oxide (CMPO) and TBP in dodecane by extraction and extraction chromatographic methods. The Pu( IV) TnOA species extracted into the organic phase from higher nitric acid concentrations has been confirmed as (R 3NH) 2Pu(NO 3) 6 (where R 3N = TnOA by employing slope analysis as well as spectrophotometric studies.

NMR study of chemical species extracted and ligand-exchange reaction in the lanthanide(III)(NO3)3CMPO system

Abstract Octyl(phenyl)- N , N -diisobutylcarbamoylmethylphosphine oxide (CMPO) is used in the TRUEX process. 31 P and 13 C NMR measurements were carried out to study the behavior of coordination of Ln(III)CMPO complexes and the ligand exchange reaction for Eu(III) and Gd(III)CMPO systems. It was found that CMPO molecules locate in the equatorial region with respect to the magnetic axis of the Ln III ions and they coordinate to the central Ln III ions in a bidentate manner with Ln III ··· O  P and Ln III ··· O  C. Although several isomers for Ln(III)CMPO complexes co-exist in CDCl 3 , a rapid intramolecular interconversion occurs at room temperature. The numbers of CMPO molecules coordinated to Eu III and Gd III ion were estimated to be 3 and 2, respectively, in CDCl 3 solution. The kinetic parameters, ΔH * and ΔS * for the ligand exchange reactions were evaluated. These ligand exchange reactions seem to proceed through a dissociative (D) mechanism.

SOLVENT EXTRACTION OF NEPTUNIUM BY n-OCTYL(PHENYL)-N,N- DIISOBUTYLCARBAMOYLMETHYLPHOSPHINE OXIDE FROM NITRIC ACID SOLUTION CONTAINING HYDROGEN PEROXIDE

ABSTRACT Solvent extraction of Np with n -octyl ( pheny1) -N, N -diisobutylcarbamoylmethylphosphine oxide (CMPO) from HNO3 solution containing H2O2 was studied from the aspect of extraction rate. Neptunium initially in the pentavalent oxidation state can be extracted by CMPO even without the addition any redox agents, but the distribution is rather low. The H2O2 was found to enhance the distribution ratio. The extraction rate was almost proportional to the 1.5-power of H2O2 concentration. The dependence of the extraction rate on HNO3 concentration was also examined. Reduction of Np(V) with H2O2 occurs rapidly in the presence of CMPO. The extraction rate is not strongly affected by the presence of tri-n-butylphosphate in the organic phase. As a diluent, decalin gives a greater extraction rate than n-dodecane.

Effect of TBP on Solvent Extraction of Np(V) with n-Octyl(pheny1)-N, N-Diisobutylcarbamoylmethylphosphine Oxide

Solvent extraction of Np(V) from nitric acid solution by n-octyl(phenyl)N-N diisobutylcarbamoylmethylphosphine oxide (CMPO) in the presence and absence of tri-n-butyl phosphate (TBP) has been studied using decalin and n-dodecane as diluents. Without the TBP, Np(V) can be extracted using CMPO in decalin with extraction equation: The maximum Np(V) distribution ratio using 0.65 M CMPO in decalin from 2 M nitric acid is 4. The net effect of TBP to CMPO at 2M nitric acid is slight suppression of Np(V) distribution ratio. However, at low CMPO concentration (0.2 M≥) after the Np(V) distribution ratio reaches the minimum value, the distribution ratio gradually increases as the TBP concentration increases. No synergistic interaction of CMPO and TBP has been observed.

Synergistic Extraction Studies Using n-Octyl(Phenyl) N,N-Diisobutylcarbamoyl-Methylphosphine Oxide

Abstract The effectiveness of n-octyl(phenyl)-N,N′-diisobutylcarbamoyl-methylphosphine oxide, CMPO, as a neutral extractant for the trivalent actinides and lanthanides from strong acid media has been well established. This investigation characterized the use of CMPO as a synergistic agent in the extraction of Am(III) and Eu(III) by thenoyltrifluoroacetone (HTTA). The distributions of the metal ions were measured using radiotracer techniques as functions of HTTA concentration, CMPO concentration and pH. The results show that the presence of CMPO enhances the extraction of Eu(III) and Am(III) by 108. The synergistic adduct was M(TTA)3·CMPO with no indication of higher complexes being formed. Unlike previous studies, the extraction of Eu(III) was more strongly enhanced than that of Am(III). The results showed little, if any, enhancement in the extraction efficiency due to the bidentate nature of the CMPO.

BEHAVIOR OF AMERICIUM IN THE STRIP STAGES OF THE TRUEX PROCESS

ABSTRACT The TRUEX (TRansUranium Extraction) process, recently developed at Argonne National Laboratory, separates and concentrates transuranium elements from acidic nuclear wastes. It is based on the use of the neutral extractant octyl(phenyl)–N,N–diisobutylcarbamoylmethylphosphine oxide (CMPO). CMPO Is combined with tributylphosphate (TBP) and a diluent to formulate the TRUEX process solvent. An attractive feature of the TRUEX process is that it allows the separation of americium from plutonium by using two different strip solutions. A detailed knowledge of the chemistry of americium in the stripping stages is essential for a successful Am/Pu separation. In this work the distribution ratio of Am(III) between TRUEX process solvent and diluted nitric acid has been measured in up to six successive strip experiments. The behavior of americlum during stripping has been correlated to the purity of the CMPO and the composition of the feed solution. With simulated waste solutions and with SX-grade CMPO, it is p...

EXTRACTION OF METAL NITRATES WITH OCTYL(PHENYL)-N,N-DIISOBUTYL- CARBAMOYLMETHYL PHOSPHINE OXIDES IN ALKANE DILUENTS AT HIGH SOLVENT LOADING∗

ABSTRACT Metal nitrates solvated by octyl(phenyl)–N,N–diisobutylcar-bamoylphosphine oxides exhibit a limited solubility in many alkane diluents even in the presence of a modifier such as tributyl phosphate. The solubility is a nonmonotonous function of the aqueous nitric acid concentration. The solubility of Nd(III) nitrate strongly increases with temperature, branching of the diluent molecule, and the concentration and the molecular weight of a trialkyl phosphate modifier. The solubility also increases when tributyl phosphate is replaced by dibutyl butylphosphonate. Increasing molecular size of n-alkane diluents and branching of the octyl group in the phosphine oxide molecule strongly suppress the solubility. With the n-octyl(phenyl) –N,N–diisobutylcarbamoyl-methylphosphine oxide extractant, the solubility of solvated Nd(III) nitrate is unlimited In the mixed isoparaffinic diluent Isopar–L, and the solvent can be loaded up to a metal to extractant ratio of 1/2. Empirical equations were derived which desc...

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.