Carbamoylmethylphosphine Oxide Research Articles

Silica extracts from fly ash modified via sol-gel methods and functionalized with CMPO for potential scavenging of rare earth elements La³⁺ and Ce³⁺

A mesoporous material was synthesized using silica extracts from fly ash and its properties were studied. Subsequently, it was functionalized with carbamoylmethylphosphine oxide (CMPO) to capture La3+ and Ce3+. The developed mesoporous material was obtained by the sol-gel method and was called Si-MMS (siliceous mesoporous materials), subsequently functionalized with APTMS (1-(2-aminoethyl)-3-aminopropyl trimethoxysilane) in a reflux system, which led to the synthesis of Si-MMS-APTMS. This derivative was modified with carbonyldiimidazole (CDI) and diethylphosphonoacetic acid, which finally resulted in the synthesis of Si-MMS-CMPO as the final product. The materials were characterized by DRIFT, XRD, SEM-EDS, TEM, XPS, elemental analysis and nitrogen isotherms at −196 °C, confirming that the synthesis and subsequent modification of the mesoporous structure was successful. Adsorption studies in batch systems indicated that the optimal pH for La3+ was 6, the Langmuir isotherm model and the non-linear Sips models were perfectly fitted and the best fitting kinetics is the Elovich model. For Ce3+ the optimal pH was 7.5, the non-linear Sips isotherm fit the best and the non-linear Pseudo-second order kinetics was the mechanism that best represents the adsorption. The maximum experimental adsorption capacity qe of La3+ was 17.00 mg g−1 and for Ce3+ was 30.09 mg g−1. In both cases, the rapid adsorption suggests an open porous matrix that facilitates the formation of chelates between the adsorbates and the phosphoryl group -PO32-.

Modulation of lanthanide luminescence by carbamoylmethylphosphine oxide ligand: A theoretical study

The antenna capacity of Phenacyldiphenylphosphine oxide (Phenac), combining C=O and P=O donor groups was established by theoretical examination of its chromophore properties, binding ability to encapsulate and stabilize lanthanide complexes and potential to sensitize the EuIII and TbIII luminescence in Eu(Phenac)2(NO3)3(H2O) (1), Eu(Phenac)2(NO3)3 (2), Eu(Phenac)3(NO3)3 (3) and Tb(Phenac)2(NO3)3(H2O) (4) complexes in vacuum, solution and solid phase. The ligand-centered singlet and triplet excited state energies, the rates and lifetimes for the rival nonradiative (S1→T1,2 intersystem crossing (ISC)) and radiative and nonradiative S1→S0 and T1→S0 relaxation were predicted by means of DFT/TDDFT/ωB97XD calculations. Similar relaxation paths were found for all complexes. The absorbed energy by Sn > 1(π-π*) states relaxed to T1min by major ISC mechanism S1→T2→T1. The long radiative lifetime of S1→S0 due to n(p(C)(O))π-π*,p(P) character facilitated the forward ISC process. The environment, Phenac's number and LnIII size affect the T1 energy ∼0.1 eV. The calculated (Phenac→EuIII) energy transfer rates suggested the most likely T1 → 5D1/5D0 channels for a population of emitting metal-centered states. The small Φ of EuIII and larger luminescence of TbIII were discussed and explained. The importance of the P=O and C=O groups for the coordination ability and absorption properties of Phenac has been elucidated.

Understanding the Complexation Behavior of Carbamoylphosphine Oxide Ligands with Representative f-Block Elements.

The complexation behavior of carbamoylmethylphosphine oxide ligands (CMPO), a bifunctional phosphine oxide, and their substituted derivatives with Ce(III), Eu(III), Th(IV), U(VI), and Am(III) was probed at the density functional theory (DFT) level. The enhanced extraction of trivalent rare earth elements by the 2-diphenylphosphinylethyl derivative over the conventional CMPO ligand is identified due to the availability of an additional P═O donor group in the former. In addition, the orbital and dispersive interactions play a vital role in the preference of Th(IV) over U(VI) during extraction using CMPO ligands. The better complexing ability of ligands having long alkyl chain substituents at the P atom is justified due to the observed enhanced dispersion interactions in these systems.

Using Metadynamics to Reveal Extractant Conformational Free Energy Landscapes.

Understanding the impact of extractant functionalization on metal-binding energetics in liquid-liquid extraction is essential to guide the development of better separation processes. Traditionally, computational extractant design uses electronic structure calculations on metal-ligand clusters to determine the metal-binding energy of the lowest energy state. Although highly accurate, this approach does not account for all of the relevant physics encountered under experimental conditions. Such methodologies often neglect entropic contributions such as temperature effects and ligand flexibility, in addition to approximating solvent-extractant interactions with implicit solvent models. In this study, we use classical molecular dynamics simulations with an advanced sampling method, metadynamics, to map out extractant molecule conformational free energies in the condensed phase. We generate the complete conformational landscape in solution for a family of bidentate malonamide-based extractants with different functionalizations of the headgroup and the side chains. In particular, we show how such alkyl functionalization reshapes the free energy landscape, affecting the free energy penalty of organizing the extractant into the cis-like metal-binding conformation from the trans-like conformation of the free extractant in solution. Specifically, functionalizing alkyl tails to the center of the headgroup has a greater influence on increasing molecular rigidity and disfavoring the binding conformation than functionalizing side chains. These findings are consistent with trends in metal-binding energetics based on experimentally reported distribution ratios. We also consider a different bidentate extractant molecule, carbamoylmethylphosphine oxide, and show how the choice of solvent can further reshape the conformational energetic landscape. This study demonstrates the feasibility of using molecular dynamics simulations with advanced sampling techniques to investigate extractant conformational energetics in solution, which, more broadly, will enable extractant design that accounts for entropic effects and explicit solvation.

Modified Diglycolamide Resin: Characterization and Potential Application for Rare Earth Element Recovery

Rare earth elements (REEs) are crucial for green energy applications due to their unique properties, but their extraction poses sustainability challenges because the global supply of REEs is concentrated in a few countries, particularly China, which produces 70% of the world’s REEs. To address this, the study investigated TK221, a modified extraction chromatographic resin featuring diglycolamide (DGA) and carbamoyl methyl phosphine oxide (CMPO), as a promising adsorbent for REE recovery. The elemental composition and functional groups of DGA and CMPO on the polystyrene-divinylbenzene (PS-DVB) support of TK221 were confirmed using scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDX), attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), and X-ray photoelectron spectroscopy (XPS). The adsorption kinetics of neodymium (Nd), yttrium (Y), cerium (Ce), and erbium (Er) followed the pseudo-second-order kinetic model and Langmuir isotherm, indicating monolayer chemisorption. Furthermore, iron (Fe) adsorption reached apparent equilibrium after 360 min, with consistent Fe adsorption observed at both 360 min and 1440 min. The inclusion of Fe in the study is due to its common presence as an impurity in most REE leachate solutions. The Fe adsorption isotherm results are better fitted with the Langmuir isotherm, implying chemisorption. Maximum adsorption capacities (qmax) of the resin were determined as follows: Nd (45.3 mg/g), Ce (43.1 mg/g), Er (35.1 mg/g), Y (15.6 mg/g), and Fe (12.3 mg/g). ATR-FTIR analysis after adsorption suggested that both C=O and P=O bands shifted from 1679 cm−1 to 1618 cm−1 and 1107 cm−1 to 1142 cm−1 for Y, and from 1679 cm−1 to 1607 cm−1 and 1107 cm−1 to 1135 cm−1 for Ce, implying possible coordination with REEs. These results suggest that TK221 has a huge potential as an alternative adsorbent for REE recovery, thus contributing to sustainable REE supply diversification.

Effect of bis(methylimidazolium) ionic liquid on the extraction of actinides and lanthanides with bis(carbamoylmethylphosphine oxide) extractant from nitric acid solutions

Abstract A novel bis(methylimidazolium) ionic liquid 3,3′-(pentane-1,5-diyl) bis(1-methylimidazolium) bis(trifluoromethanesulfonul)imide [C5(mim)2][Tf2N]2 has been synthesized. Its effect on the extraction of U(VI), Th(IV), Am(III), and lanthanides(III) from nitric acid solutions with a polydentate neutral bis(carbamoylmethylphosphine oxide) ligand L containing two bidentate fragments Ph2P(O)CH2C(O)NH–, interconnected by 4,7,10-trioxatridecane spacer through amide nitrogen atoms has been investigated. The efficiency of the extraction of metal ions with solutions of L in 1,2-dichloroethane (DCE) significantly increases in the presence of [C5(mim)2][Tf2N]2. A synergistic effect in the extraction of metal ions in this system has been explained with the high hydrophobicity of the Tf2N− anions, which are involved in the formation of extracted complexes as counterions. The value of the synergistic effect decreases with increasing acidity of the aqueous phase. The influence of the composition of the aqueous and organic phases on the efficiency of the extraction of metal ions into the organic phase is considered, and the stoichiometry of the extracted complexes is determined. The effect of the HTf2N coextraction with L on the extraction of metal ions in the L – [C5(mim)2][Tf2N]2 system is discussed. The synergistic effect in the extraction of Ln(III) from 3 M HNO3 solutions with the mixture of L and [C5(mim)2][Tf2N]2 in DCE is higher than that in the L – [C4mim][Tf2N] – DCE system.

Diphenyl(N-alkyl-N-diphenylphosphinylmethyl)carbamoylmethylphosphine Oxides: Synthesis and NMR Spectroscopy Study

Diphenyl(N-alkyl-N-diphenylphosphinylmethyl)carbamoylmethylphosphine Oxides: Synthesis and NMR Spectroscopy Study

Extraction of REE(III), U(VI), and Th(IV) with Modified Carbamoylmethylphosphine Oxides from Nitric Acid Solutions

Extraction of REE(III), U(VI), and Th(IV) with Modified Carbamoylmethylphosphine Oxides from Nitric Acid Solutions

Competing N vs. P(O),C(O)-coordination in complexes of mono- and bis-1,2,3-triazole ligands modified by carbamoylmethylphosphine oxide fragments with palladium(II), uranyl(II), and lanthanum(III): Solid and solution structures

Six new complexes [PdCl2(L1)2] (1), [PdCl2(L2)2]·2H2O (2), [PdCl2(L3)] (3), [UO2(L2)(NO3)2]·MeCN, (4), [(UO2)2(L3)(NO3)4] (5), [La(L2)2(NO3)3] (6) (L1 – 1-phenyl-4-propyl-1,2,3-triazole, L2, and L3 – mono- and bis-1,2,3-triazole ligands decorated with carbamoylmethylphosphine oxide (CMPO) fragments, respectively) were synthesized and characterized by elemental analysis and IR and Raman spectroscopy. The structures of complexes 1, 2, 4–6 have been determined by single-crystal X-ray crystallography. The ligands L2 and L3 display P(O),C(O) coordination mode with U(VI), and La(III), but N3 mode with Pd(II) in both solid state and solutions. Various intra- and intermolecular hydrogen bonding interactions involving nitrogen and hydrogen atoms of 1,2,3-triazole fragments were revealed in all studied crystalline complexes irrespective of whether triazole fragment coordinates to metal cation (1, 2) or not 4–6). The complex 1 displayed non-classical triazolyl CH…Cl– hydrogen bonding. These hydrogen bonds were also studied by QTAIM theory. Normal coordinate analysis of the vibrations at the DFT level was performed for the ligand L1 and its complex 1. Solution structure of all complexes has been investigated by IR and multinuclear (1H, 13C, and 31P) NMR spectroscopy. Extraction efficiency of Pd(II), U(VI), and La(III) from 3 M HNO3 into 1,2-dichloroethane using extractants L2 and L3 and the known CMPO extractant – Ph2P(O)CH2C(O)NBu2 is discussed in comparison with structure of the corresponding complexes in solutions.

Extraction of REE(III), U(VI), and Th(IV) from Nitric Acid Solutions with N-Akyl(aryl)carbamoylmethylphosphine Oxides in the Presence of an Ionic Liquid

Extraction of REE(III), U(VI), and Th(IV) from Nitric Acid Solutions with N-Akyl(aryl)carbamoylmethylphosphine Oxides in the Presence of an Ionic Liquid

Extraction of Rare Earth Elements(III) with Mixtures of Some New Tridentate Carbamoylmethylphosphine Oxides and 4-Benzoyl-3-methyl-1-phenyl-1H-pyrazol-5(4H)-one from Hydrochloric Acid Solutions

Extraction of Rare Earth Elements(III) with Mixtures of Some New Tridentate Carbamoylmethylphosphine Oxides and 4-Benzoyl-3-methyl-1-phenyl-1H-pyrazol-5(4H)-one from Hydrochloric Acid Solutions

XAS study of americium complexes with calixarene bearing carbamoylmethylphosphine oxide moieties

The local environment of a novel group of americium (Am3+) complexes with calix[4]arene bearing carbamoylmethylphosphine oxide moieties on the upper rim has been investigated by X-ray absorption spectroscopy. The complexes were obtained by the extraction of americium from aqueous nitric or 2-(1-adamantyl)sulfoacetic acids with the 1,2-dichloroethane solution of this ligand. The correlation of the structures of the obtained complexes with americium distribution coefficients in the corresponding extraction systems is revealed.

New Tridentate Carbamoylmethylphosphine Oxides: Synthesis and NMR Spectra

Amidation of diphenylphosphorylacetic acid gave tridentate ligands Ph2P(O)CH2CON(R)· CH2CH2P(O)Ph2 (R = Me, Bu, Oct) containing a phosphoryl group in the amide moiety. According to the 1H, 13C{1H}, and 31P{1H} NMR spectra, the synthesized compounds exist in CDCl3 solution as two conformers at the ratios of ~2.5 : 1 (R = Me), 2.6 : 1 (R = Bu), and 3.0:1 (R = Oct). These ratios do not change with temperature (heating or cooling).

Extraction of Rare Earth Elements(III) from Nitric Acid Solutions with Binary Extractants Based on Dialkylamino Derivatives of Carbamoylmethylphosphine Oxides and Dinonylnaphthalenesulfonic Acid

Interphase distribution of La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, and Y between aqueous HNO3 solutions and solutions of binary extractants obtained by reaction of equimolar amounts of dialkylamino derivatives of carbamoylmethylphosphine oxides and dinonylnaphthalenesulfonic acid in organic solvents has been studied. Stoichiometry of extracted complexes has been determined, effect of HNO3 concentration in aqueous phase and organic solvent nature on the efficiency of metal ion recovery into organic phase has been considered. On the formation of extractable REE(III) complexes, the cationic moiety of binary extractant provides coordination solvation of REE(III) ions, while anionic moiety offers their high hydrophobicity, which favors to the efficient transition of metal ions into organic phase.

Comparative evaluation of extraction of tetra- and hexa-valent neptunium ions by CMPO in a room temperature ionic liquid

ABSTRACT Solvent extraction studies were performed to understand the extraction behavior of Np4+ and NpO2 2+ from acidic feeds with CMPO (octyl (phenyl)-N,N-diisobutyl carbamoyl methyl phosphine oxide) dissolved in 1-butyl-3-methylimidazolium bis(trifluoromethane sulfonyl)imide, a water immiscible ionic liquid. Slope analyses on the distribution data revealed the extraction of ML2 type species, where M = Np4+ or NpO2 2+, and L = CMPO. Studies were also carried out with Pu4+ and UO2 2+ under identical conditions. The nature of the extracted species was found to vary with the nature of the ionic species.

Extraction of Rare Earth Elements from Hydrochloric Acid Solutions with Carbamoylmethylphosphine Oxides in the Presence of Quaternary Ammonium Dinonylnaphthalenesulfonates

Interphase distribution of La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, and Y between aqueous HCl solutions and solutions of carbamoylmethylphosphine oxides in the presence of binary extractants, quaternary ammonium dinonylnaphthalenesulfonates, has been studied. It has been shown that the efficiency of extraction of rare earth elements(III) (REE) with carbamoylmethylphosphine oxides increases considerably in the presence of binary extractant in organic phase. The stoichiometry of extracted complexes has been determined, effect of cation nature of the binary extractant, organic solvent, structure of carbamoylmethylphosphine oxides, and HCl concentration in aqueous phase on efficiency of REE(III) recovery into organic phase has been considered.

Extraction of lanthanides(III) from Perchlorate Solutions with Carbamoyl- and Phosphorylmethoxymethylphosphine Oxides and Tetrabutyldiglycolamide

ABSTRACT The solvent extraction of Ln(III) ions from perchlorate aqueous solutions into an organic phase containing neutral polyfunctional organophosphorus ligands R2P(O)CH2OCH2C(O)NBu2 R = Bu (I), R = Ph (II) and R2P(O)CH2OCH2P(O)R1 2 R = R1 = Bu (III); R = Bu, R1 = Ph (IV); R = R1 = Ph(V) has been studied. Their extraction behavior was compared with that of tetrabutyldiglycolamide (TBDGA), tetrabutylmethylenediphosphine dioxide (VI), P,P-dibutyl-P’P’-diphenylmethylenediphosphine dioxide (VII), tetraphenylmethylenediphosphine dioxide (VIII), dibutyl-N,N-dibutylcarbamoylmethylphosphine oxide (IX) and diphenyl-N,N-dibutylcarbamoylmethylphosphine oxide (X). The extraction equilibrium was investigated, and the equilibrium constants were calculated. It was found that the lanthanide(III) ions are extracted with the studied extractants from perchlorate solutions as LnL3(ClO4)3 complexes. In the NaClO4 media, TBDGA was found to possess a higher extraction efficiency towards Ln(III) ions than other neutral donor ligands studied. A successive replacement of the C(O)NBu2 groups in the diglycolamide extractant molecule by phosphoryl ones leads to a decrease in the extraction efficiency of Ln(III) ions. In the NaClO4 media, compounds II, IV and V with phenyl radicals at the P(O) group demonstrate a lower extraction efficiency towards Ln(III) ions than their butyl-substituted analogs. In contrast, phenyl-substituted diphosphine dioxides VIII, VII and carbamoylmethylphosphine oxide (X) extract Ln(III) ions more effectively than their butyl-substituted analogs VI and IX. The extraction of Ln(III) ions from HClO4 solutions is accompanied by HClO4 interaction with neutral donor extractants, which leads to a decrease of the free extractant concentration in the organic phase. By this reason, an increase in the HClO4 concentration higher than 0.1 M is accompanied by a decrease of the Ln(III) extraction with TBDGA. In the 3 M HClO4 system, diphosphine dioxide VIII outperforms TBDGA at the Ln(III) extraction.

Probing the absence of third phase formation during the extraction of trivalent metal ions in an ionic liquid medium

In contrast to molecular diluents, diglycolamide (T2EHDGA) and carbamoylmethyl-phosphine oxide (CMPO) extractants diluted in an ionic liquid diluent minimize aggregation upon nitric acid extraction and prevent third phase formation during the course of solvent extraction.

Extraction of REE(III), U(VI), and Th(IV) from Nitric Acid Solutions with Carbamoylmethylphosphine Oxides in the Presence of Dinonylnaphthalenesulfonic Acid

The extraction of REE(III), U(VI), and Th(IV) from nitric acid solutions with solutions of carbamoylmethylphosphine oxides (CMPOs) considerably increases in the presence of dinonylnaphthalenesulfonic acid. The stoichiometry of the extractable complexes was determined, and the influence of the aqueous phase composition, kind of organic diluent, and CMPO structure on the efficiency of the extraction of the metal ions was analyzed.

Carbamoylmethylphosphine oxide functionalised porous crosslinked polymers towards sequential separation of uranium (VI) and thorium (IV)

A new class of highly crosslinked porous polymeric materials with an ethylene glycol dimethacrylate (EGDMA) backbone appended with carbamoylmethylphosphineoxide (CMPO) ligands has been synthesized via precipitation polymerization. The polymers were characterized by CP-MAS NMR, FT-IR, DSC-TGA, SEM and elemental analysis. The polymers prepared in various porogens were evaluated by nitrogen adsorption/desorption experiments, which revealed the existence of large pore volume and surface areas. The ability of polymers to extract actinides (U, Th, Am) utilizing solid phase extraction (SPE) strategy by batch sorption methods as a function of nitric acid concentration are studied. The crosslinked polymers show - a good sorption ability towards U(VI), Th(IV) and Am(III); − selective extraction of U(VI) over Th(IV); and -high radiolytic stability towards gamma radiation. The effect of porogen on pore structure, sorption kinetics, metal loading, release behavior and recycling studies were also discussed. Sequential and selective separation of U(VI) and Th(IV) was demonstrated by extraction chromatography.