Carbamoylmethylphosphine Oxide Research Articles

Characterization of CMPO and its radiolysis products by direct infusion ESI-MS

Direct infusion electrospray ionization mass spectrometry (ESI-MS) approaches were developed for rapid identification of impurity compounds formed from octylphenyl-(N,N-(diisobutyl)carbamoylmethyl) phosphine oxide (CMPO) during alpha and gamma irradiation experiments of this compound in dodecane. CMPO is an aggressive Lewis base, and produces extremely abundant metal complex ions in the ESI-MS analysis that make identification of low abundance compounds that are less nucleophilic challenging. Radiolysis products were identified using several approaches including restricting ion trapping so as to exclude the abundant natiated CMPO ions, extraction of acidic products using aqueous NaOH, and extraction of basic products using HNO3. These approaches generated protonated, natiated and deprotonated species derived from CMPO degradation products formed via radiolytic cleavages of several different bonds. Cleavages of the amide and methylene–phosphoryl bonds appear to be favored by both alpha and gamma irradiation, while alpha irradiation also appears to induce cleavage of the methylene–carbonyl bond. The degradation products observed are formed from recombination of the initially formed radicals with hydrogen, methyl, isopropyl and hydroxyl radicals that are derived either from CMPO, contacted aqueous nitric acid, or the dodecane solvent.

1,3-Bis[(diphenylphosphorylacetamido)methyl]benzene as reagent for extraction and sorption preconcentration of REE(III), U(VI), and Th(IV) from nitric acid solutions

The extraction of microamounts of REE(III), U(VI), and Th(IV) from HNO3 solutions in the form of complexes with a polyfunctional neutral organophosphorus compound, 1,3-bis[(diphenylphosphorylacetamido)-methyl]benzene, was studied. The influence exerted by the structure of the bridge binding two carbamoylmethyl-phosphine oxide fragments on the efficiency of the extraction of REE(III), U(VI), and Th(IV) and on the stoichiometry of the extractable complexes was analyzed. The possibility of recovering and concentrating REE(III), U(VI), and Th(IV) from nitric acid solutions with a complexing sorbent prepared by noncovalent immobilization of 1,3-bis[(diphenylphosphorylacetamido)methyl]benzene on the surface of carbon nanotubes was examined.

N-Tris[(2-aminoethyl)-2-(diphenylphosphoryl) acetamide)] — novel CMPO tripodand: synthesis, extraction studies and luminescent properties of lanthanide complexes

Abstract A ligand system containing three carbamoylmethylphosphine oxide (CMPO) moieties attached to a tripodal platform with a central nitrogen atom has been synthesized for metal complexation and extraction from neutral and nitric acid solutions. Liquid-liquid extractions performed for Ln(III), both from neutral and acidic media, show excellent extraction properties which exceeded those for the known mono- and di-CMPO derivatives as well as the related tripodands. A considerable enhancement of the DLn values was observed in the presence of IL ([bmim][Tf2N]) in the organic phase towards lanthanide ions from 3M HNO3 solutions. The protonation of the central amine nitrogen atom of the ligand 1 in the acidic media provides also the effective extraction of the perrhenate anionic complexes. The europium complexes formed by mono- and tris-CMPO ligands in the solid state, as well as Eu(III) and Tb(III) complexes generated in solutions, possess intensive luminescence at 300K

Aqueous Partitioning of Minor Actinides by Different Processes

Actinide partitioning is a proposed strategy for effective mitigation of the long-term hazards associated with high-level waste (HLW). Octyl-(phenyl)–N,N-diisobutyl carbamoyl methyl phosphine oxide (CMPO) and diphenyl–N,N-diisobutyl carbamoyl methyl phosphine oxide (DφCMPO) are amongst the promising extractants extensively studied since the 1980s for actinide partitioning from wastes of different origin. During the last two decades, substituted malonamide extractants such as N,N'-dimethyl-N,N'-dibutyl tetradecyl malonamide (DMDBTDMA) and N,N'-dimethyl-N,N'-dioctyl hexylethoxy malonamide (DMDOHEMA) have emerged as viable green alternatives to phosphine oxides. During the last decade, diglycolamide-based extractants such as N,N,N′,N′-tetraoctyl diglycolamide (TODGA) and N,N,N′,N′-tetra-2-ethylhexyl diglycolamide (TEHDGA) have received considerable attention due to overwhelmingly favourable extraction and stripping efficiencies of minor actinides from different types of transuranium (TRU) wastes. The focus of the present review is to carry out comparative evaluation of the key physical and chemical properties of these extractants for hydrometallurgical applications. Merits of flow sheets proposed for the separation and recovery of minor actinides from high-level wastes have also been discussed.

Influence of ionic liquids on actinides extraction by diphenyl(dibutyl)carbamoylmethylphosphine oxide in different solvents from nitric acid solution

Influence of ionic liquids (ILs) addition (1–50 wt%) on extraction efficiency of actinides by diphenyl(dibutyl)carbamoylmethylphosphine oxide (Ph2Bu2) from 3 M HNO3 has been studied. Am(III) distribution ratios in two-phase systems 0.1 M Ph2Bu2 in either DCE or CHCl3–3 M HNO3 depending on the nature of additional ionic liquids: imidazolium-based ILs: [C4mim][PF6], [C4mim][BF4] and phosphonium-based ILs: PPF6, PBF4 and PCl were determined. The highest value of Am(III) extraction ratio change (1040) was found on addition of PPF6 to Ph2Bu2 in CHCl3. Extraction of Pu(IV) and U(VI) by 0.001 M Ph2Bu2 in the presence of [C4mim][PF6] in DCE, CHCl3 or meta-nitrobenzotrifluoride (NBTF) have been investigated. The greatest enhancement of extraction efficiency was observed using CHCl3, the least polar studied solvent. Using a mixture of conventional solvent and ionic liquid as a solvent for extractant enables one to increase distribution ratios and reduce viscosity of organic phase as compared with ionic liquid viscosity. The marked increase of Am(III), Pu(IV) and U(VI) extraction extent by Ph2Bu2 on addition of ionic liquids to the extent of 10 wt% permit one essentially to diminish amounts considerably more expensive carbamoylmethylphosphine oxide(the general name is CMPO) used in TRUEX process.

Recent Advances in Extraction and Separation of Rare-Earth Metals Using Ionic Liquids

In the present review article, we summarize recent advances in extraction and separation of rare-earth metals using ionic liquids. Rare-earth metals have unique electronic and magnetic properties. In Japan, increasing amounts of rare-earth metals are being used every year in industries employing cutting-edge technology. Therefore, maintaining a stable supply of rare-earth metals is important. In recent times, extensive research has been carried out on the use of ionic liquids for the extraction of rare-earth metals; this is because the extraction ability and/or selectivity for rare-earth metals have been found to increase when using hydrophobic ionic liquids, which have potential applications in liquid–liquid extraction processes. In the octyl(phenyl)-N,N-diisobutyl carbamoylmethyl phosphine oxide (CMPO) extraction system using ionic liquids, the extraction ability was more than 103 times better than that when using n-dodecane; however, stripping of the extracted metal ions was difficult in the former case. In initial research on the extraction processes based on ionic liquids, industrial extractant PC-88A was employed as well as CMPO, but issues resulting from the low solubility of these extractants and their metal complexes remain to be addressed. To overcome this problem, a new extractant, N,N-dioctyldiglycol amic acid (DODGAA), which is highly soluble in the ionic liquids, has been synthesized. DODGAA shows better performance for the separation of rare-earth metals in ionic liquids than in n-dodecane. Furthermore, a liquid membrane system based on ionic liquids has been developed for the separation and recovery of rare-earth metals. The use of a liquid membrane system may help in reducing the amount of ionic liquids required for metal recovery.

Third phase formation in the extraction of nitric acid and metal ions by octyl(phenyl)-N,N-diisobutyl carbamoyl methyl phosphine oxide (OΦCMPO) based solvents

Formation of a third phase in the extraction of nitric acid and metal ions such as Th(IV), U(VI), La(III), Ce(III), and Gd(III) by OΦCMPO based solvents has been investigated under various conditions. The limiting organic concentrations (LOC) and critical aqueous concentrations (CAC) for third phase formation in the extraction of nitric acid by 0.2 M OΦCMPO + 1.2 M TBP in n-tetradecane and 0.2 M OΦCMPO + 1.2 M TBP in n-hexadecane were measured as a function of temperature. Extraction of nitric acid by these solvents as a function of equilibrium aqueous phase acidity at 303 K has been studied. Distribution of nitric acid between diluent-rich phase (DP) and third phase (TP) in the extraction of nitric acid by these solvents has also been studied as a function of equilibrium aqueous phase acidity at 303 K. Densities of diluent-rich phase, third phase, and aqueous phase have been measured as a function of equilibrium aqueous phase acidity at 303 K. Third phase formation in the extraction of Th(IV), U(VI), La(...

ChemInform Abstract: Steric Aspects of Selectivity of Organophosphorus Extractants.

This paper is devoted to the steric aspects of the efficiency and selectivity of extractants in the process of extraction of metal cations from acidic aqueous solution into a nonpolar phase. The extraction of uranium, plutonium, americium, and europium by tertiary carbamoylmethyl phosphine oxides and polydiphenylphosphinylmethyl benzenes have been studied. The separation factors of uranium and plutonium from americium are measured. Tertiary carbamoylmethyl phosphine oxides and diphenylphosphinylmethyl benzenes of the ortho type are characterized by unusually high separation factors. The diphenylphosphinylmethyl derivatives of benzene of the meta type do not possess a high selectivity in the process of separation of uranium and plutonium from americium, but are more efficient in extraction of americium.

Dimeric Capsules Formed by Tetra‐CMPO Derivatives of (Thia)Calix[4]arenes

Thiacalix[4]arene 2, calix[4]arene 3a and its tetraether fixed in the cone conformation 3b form homo- and heterodimeric capsules in apolar solvents, which are held together by a seam of NH...O=P hydrogen bonds between carbamoylmethyl phosphine oxide functions attached to their wide rim. Their internal volume of approximately 370 A(3) requires the inclusion of a suitable guest. Although neutral molecules such as adamantane (derivatives) or tetraethylammonium cations form kinetically stable complexes ((1)H- and (31)P-time scale), the included solvent is rapidly exchanged. The internal mobility of the included tetraethylammonium cation is distinctly higher (DeltaG=42.5 and 49.7 kJ mol(-1) for 3a and 3b) than that for similar capsules of tetraurea calix[4]arenes 1. Mixtures of 1 with 2, 3a, or 3b contain only the two homodimers but the heterodimerization occurs with the tetraloop tetraurea 6, which cannot form homodimers. Two dimers with cationic guests (2.(C(5)H(5))(2)Co(+).2 and 3a.Et(3)NH(+).H(2)O.3a) were confirmed by single-crystal X-ray analysis.

Functional magnetic nanoshells integrated nanosensor for trace analysis of environmental uranium contamination

Transuranic radionuclides such as uranium tend to be a pervasive environmental contaminant. It is absorbed through the intestine or a lung, deposited in the tissues, predominantly kidney and bone, and is carcinogenic. A novel nanosensor system has been developed for voltammetric tracing of environmental uranium contamination. The sensor consists of an organophosphorous ligand, ( t-butylphenyl)- N, N-di-(isobutyl) carbamoylmethylphosphineoxide (CMPO) functionalized superparamagnetic core–shell magnetic nanoparticles and magnet based electrodes. It exploits the natural affinity of uranium for phosphate molecules to fabricate a highly specific and reproducible sensor. The small dimension along with a dramatically increased contact surface has lead to a faster response and higher sensitivity. The system uses an external magnetic field gradient for preconcentration and removal of the analyte from the surrounding aqueous media. The redox properties of the analyte are exploited for enumeration of variables by electrochemical techniques such as square wave voltammetry. The detection limit of the system is observed to be in parts-per-billion (ppb) of the uranyl concentration.

Tetra-CMPO-derivatives of calix[4]arenes fixed in the 1,3-alternate conformation

Calix[4]arene derivatives fixed in the 1,3-alternate conformation and substituted at one side by four carbamoylmethylphosphine oxide (CMPO) residues were synthesised. Two CMPO groups are directly attached to the wide rim, while the second pair is bound to the narrow rim via a tri- or tetramethylene spacer. Similar compounds, in which two CMPO groups at the wide rim are combined with two picolinamide groups or two ionisable carboxylic groups at the narrow rim, were also prepared. Some of these calixarene derivatives were studied as extractants for lanthanides (La3+, Eu3+, Yb3+) and thorium (Th4+) from acidic solution into methylene chloride. For selected samples, stability constants in methanol were determined by spectrophotometric titrations. Three compounds (1b′, 13, 17) in the 1,3-alternate conformation and one intermediate in the cone conformation (18) were confirmed by a crystal structure.

Review: Solvent Systems Combining Neutral and Acidic Extractants for Separating Trivalent Lanthanides from the Transuranic Elements

This paper is a review of recent publications that have focused on combined extractant systems for separating trivalent actinides from the lanthanides. These mixed solvent systems combine an acidic extractant with a neutral extractant to achieve the actinide/lanthanide separation. Depending on the neutral extractant used, three categorizations of systems can be considered, including combinations of acidic extractants with 1) diamides, 2) carbamoylmethylphosphine oxides, and 3) polydentate nitrogen-donor ligands. This review of relevant publications indicates that, although there is significant potential for practical exploitation of mixed neutral/acidic extractant systems to achieve a single-step separation of trivalent actinides from acidic high-level waste solutions, the fundamental chemistry underlying these combined systems is not yet well understood. For example, although there is strong evidence suggesting that adducts form between the neutral and acidic extractants, the nature of these adducts generally is not known. Likewise, the structures of the mixed complexes formed between the metal ions and the two different extractants are not fully understood. Research into these basic phenomena likely will provide clues about how to design practical mixed-extractant systems that can be used to efficiently separate the transuranic elements from the lanthanides and other components of irradiated fuel.

Transport of americium(III) across SLM containing CMPO as the carrier extractant

The transport behaviour of Am3+ was investigated from nitric acid as well as from aqueous nitrate media under neutral pH conditions across PTFE flatsheet supports (0.45 micron) containing octyl,phenyl-N,N-di-iso-butyl carbamoylmethyl phosphine oxide (CMPO) as the carrier extractant. The effect of CMPO concentration and presence of tri-n-butyl phosphate (TBP) as phase modifier was studied. The results showed strong influence of hydrogen ion on Am(III) transport which was more pronounced in the presence of TBP. Acid transport data along with permeability coefficients for Am(III) transport are also presented.

Studies on the Recovery of Uranium from Phosphoric Acid Medium Using Synergistic Mixture of 2-Ethyl Hexyl Hydrogen 2-Ethyl Hexyl Phosphonate and Octyl(phenyl)-N,N-diisobutyl Carbamoyl Methyl Phosphine Oxide

This paper describes the extraction of uranium from aqueous phosphoric acid medium using 2-ethyl hexyl hydrogen 2-ethyl hexyl phosphonate (PC88A) and octyl (phenyl)-N,N-diisobutylcarbamoylmethylphosphine oxide (CMPO) individually as well as their synergistic mixture in different diluents. The extraction parameters such as variation in concentration of either of the extractants, concentration of H3PO4 and uranium in the aqueous phase are investigated to optimize the extraction conditions. Results indicate that the synergistic mixture, 0.9 M PC88A + 0.1 M CMPO in xylene, can be used for the extraction of uranium from the phosphoric acid medium. The loaded uranium from the synergistic organic phase can be stripped using 0.5 M solution of (NH4)2CO3. This synergistic mixture is used to recover uranium from a typical wet process phosphoric acid sample and the recovery is found to be better than 90%.

Complexation of N-alkyl(aryl)- and N,N-dialkylcarbamoylmethylphosphine oxides with the f-elements

Complexation of N-alkyl(aryl)carbamoylmethylphosphine oxides (CMPO) and their N, N-dialkyl analogs in neutral media was studied. N-Alkyl derivatives react with praseodymium and europium nitrates both in solution and in the individual state to give 1: 2 and 1: 3 complexes, depending on the ratio of the starting reagents; for N-aryl amides, 1: 3 complexes were obtained only. With the uranyl cation, both N-alkyl and N,N-dialkyl derivatives of CMPO form various 1: 1 complexes.

A novel facile synthesis of carbamoylmethylphosphine oxides in ionic liquids

A convenient access to carbamoylmethylphosphine oxides (CMPO) in up to 96% isolated yield is developed via direct amidation of diphenylphosphoryl acetic acid in an ionic liquid as a recyclable reaction medium in the presence of triphenyl phosphite. The influence of the nature of the amine and anion and cation structure in the ionic liquid on the reaction rate and yields of the products are also investigated. 1-Butyl-3-methylimidazolium bromide [bmim]Br and trihexyltetradecylphosphonium chloride [P(C 6H 13) 3(C 14H 29)]Cl proved to be the best media for carrying out this reaction.

Solvent extraction studies of Pu(IV) with CMPO in 1-octyl 3-methyl imidazolium hexa fluorophosphate (C8mimPF6) room temperature ionic liquid (RTIL)

Solvent extraction studies of Pu(IV) from aqueous nitric acid by carbamoyl methyl phosphine oxide (CMPO) in 1-octyl 3-methyl imidazolium hexa fluorophosphate (C8mimPF6) room temperature ionic liquid (RTIL) were carried out. It was inferred that the stoichiometry of the Pu(IV) species extracted into RTIL phase, through cation exchange mechanism, is [Pu(NO3)(CMPO)x]+3 where x varies from 1 to 2 under the experimental conditions used. Thermodynamic parameters showed the extraction to be favoured by negative enthalpy change, but counteracted by negative entropy change.

Cross-sensitive rare earth metal ion sensors based on extraction systems

Abstract A variety of new chemical sensors for determination of triple charged rare earth (RE) metal cations from lanthanum(III) to lutetium(III) (lanthanides) has been developed and studied. Well-known extractants—bidentate neutral organophosphorous compounds, such as methylene diphosphine dioxides and carbamoylmethylphosphine oxides and tetraoctyl-3-oxapentanediamide (TODGA) were used as neutral ligands in the polymeric sensor membranes. It was found that addition of certain substances that are called “anionic modifiers” in sensor terminology (tetra-bistrifluoromethylphenyl-borate (TFPB), chlorinated cobalt dicarbollide (CCD)) often results in increase of sensor sensitivity to lanthanides. Different sensors based on the extractants exhibit remarkable sensitivity to RE metal cations and their selectivity (cross-sensitivity) can be widely governed by changing the composition of the membranes. Chemical sensors based on the extractants show good promise for analysis of RE mixtures in complex solutions containing various other components. The developed sensors can be particularly interesting for the analysis of highly radioactive liquid waste (HLW).

CMPO-Functionalized C3-Symmetric Tripodal Ligands in Liquid/Liquid Extractions: Efficient, Selective Recognition of Pu(IV) with Low Affinity for 3+ Metal Ions

Structural modifications of carbamoylmethylphosphine oxide (CPMO)-functionalized triphenoxymethane platforms are described, and the influence of these changes on the ability of the ligand to extract actinides from simulated acidic nuclear waste streams has been evaluated. The ligand system has been shown to have excellent binding efficiency and a selectivity for An(IV) in comparison to the a simple monomeric CMPO ligand under analogous conditions. Both the extraction efficiency and selectivity are strongly dependent on the flexibility and electronic properties of the ligating units in the triphenoxymethane construct. The Tb(III) and Bi(III) nitrate complexes of tris-CMPO derivatives have been isolated, and their structures were elucidated by NMR, ESI FT-ICR MS, and X-ray analysis, providing information on the interactions between metal ions and the tris-CMPO molecules.

Removal of plutonium and americium from waste matrices by supercritical carbon dioxide extraction

The extraction of plutonium from tissue paper matrix was carried out using supercritical carbon dioxide (Sc-CO2). The removal of plutonium was also studied from other matrices such as teflon, glass and stainless steel. Initial experiments were carried out under subcritical conditions. Supercritical extraction conditions were also employed in some experiments for the recovery of plutonium from tissue paper matrix. Complete extraction of Pu(III) as well as Pu(IV) in their nitrate form from tissue paper was achieved for the first time using supercritical carbon dioxide modified with n-octyl(phenyl)-N,N-diisobutyl carbamoylmethyl phosphine oxide (φCMPO) in methanol. Pu(IV) was also completely removed from other matrices such as teflon, stainless steel and glass. Studies on the extraction of Am(III) using supercritical carbon dioxide modified with CMPO in methanol resulted in its complete recovery from tissue paper.