Hydrogen Phosphonate Research Articles

Efficient adsorption of thorium and cerium from Rosetta monazite concentrate using a novel phosphorylated Schiff-base adsorbent

(Pyridine-2,5-diylbis(azaneylylidene)) bis-(methaneylylidene)) bis(benzene-5,1,3-triyl) tetrakis (hydrogen phosphonate) (PZMB) was successfully synthesized for Th(IV) and Ce(IV) adsorption, the adsorption parameters evaluated and found to be pH 3.5, time 60 min, dose 0.15 g. Adsorption kinetics, isotherm, and thermodynamics studies. Adsorption kinetics studies show that adsorbent follow pseudo-second-order model while isotherm studies conclude that adsorption processes fitted Langmuir and D-R isotherm model. The maximum adsorption capacity of BZMB of Th(IV) and Ce(IV) are 366.4 and 244.53 mg/g respectively, Thermodynamic studies indicate both adsorption processes exhibited by the PZMB were endothermic, spontaneous and sorption occurs in a random manner.

Fabrication of an innovative phosphonate Schiff base adsorbent for molybdenum adsorption and its applications for molybdenum adsorption from spent hydrodesulfurization catalyst

AbstractBACKGROUNDTo investigate the recovery of molybdate from water and hydrodesulfurization catalysts, a novel synthesized phosphonate Schiff base, 4,4′‐(((2,2‐dimethylpropane‐1,3‐diyl) bis(azaneylylidene)) bis(methaneylylidene)) bis(2‐methoxyphenol) (HMI) and 4‐(((3‐((4‐(((S)‐hydroxyhydrophosphoryl)oxy)‐3‐methoxybenzylidene) amino)‐2,2‐dimethylpropyl)imino)methyl)‐2‐methoxyphenyl hydrogen phosphonate (HIMP), was utilized. This study aimed to assess the structural and property aspects of this synthesized compound using diverse characterizations, including FTIR, Thermogravimetric Analysis (TGA), mass spectrometry (GC–MS), fluorescence transfer spectra, scanning electron microscopy (SEM), and 1H‐NMR, 13C‐NMR, and 31P‐NMR.RESULTSThe study systematically examined several factors controlling molybdate recovery, including temperature, adsorbent dosage, pH, interaction time, and molybdate concentration using the batch technique. Optimal sorption effectiveness was achieved at pH 2, with an interaction time of 40 min, a 0.06 g adsorbent dose, at ambient temperature. The newly devised adsorbent exhibited an impressive adsorption capacity (Qe) of 372.54 mg of Mo per gram, with empirical data fitting the Langmuir and D‐R adsorption models. The kinetics of molybdate uptake followed second‐order kinetics. Thermodynamic aspects, including ΔG°, ΔS°, and ΔH°, were also investigated, providing appreciated perceptions into the energetic dynamics of the sorption process. Additionally, molybdate adsorption in the occurrence of other ions was explored, highlighting the selectivity of the modified phosphonate Schiff base for molybdate removal.CONCLUSIONThe study underscores the potential of the modified phosphonate Schiff base as a crucial adsorbent for molybdate elimination from both solutions and spent hydrodesulfurization catalysts. The findings offer important insights into the adsorption kinetics, thermodynamics, and selectivity of the adsorbent, enhancing our understanding of molybdate recovery processes and their broader applications. © 2024 Society of Chemical Industry (SCI).

Solubility of di-cyclohexylhydrogen phosphonate in supercritical carbon dioxide medium: Application towards the recovery of uranium from aqueous solution

Hydrogen phosphonates are di-esters of phosphonic acids and are widely employed as ligands for recovery of actinide species from different matrices. An alicyclic hydrogen phosphonate, namely, di-cyclohexylhydrogen phosphonate (DCyHeHP) is synthesized; its solubility in supercritical carbon dioxide medium is evaluated towards development of a supercritical fluid extraction (SFE) method for recovery of actinide species. The solubility experiments were carried out at three isotherms (313 K, 323 K, and 333 K) with pressure varying from 10 MPa − 20 MPa, using a dynamic flow method. The mole fraction solubility ranges from 0.2 × 10-3 to 102 × 10-3 in the investigated region. The experimental solubility data was modelled using five semi-empirical equations; Mendez-Santiago, Chrastil, del Valle, Adachi Lu and Sparks equations. The experimental data was found to be self-consistence based on Mendez-Santiago equation. The prediction ability of these models was compared using absolute average relative deviation (AARD) and corrected Akaike Information Criterion (AICc). Among the models employed in the present study, Adachi Lu equation found to better with an AARD and AICc value of 4.2% and 87.2 respectively. Based on the solubility data, SFE method was developed for the selective recovery of uranium from representative fission product elements from an aqueous solution using SCCO2 containing DCyHeHP.

Synthesis of Phosphachromones by Cyclized Coupling of Ethyl Hydrogen (Phenylethynyl)phosphonate with Arynes.

A straightforward and efficient strategy for the synthesis of phosphachromones has been reported via the insertion of arynes into P-O bonds. This operationally simple reaction is compatible with different functional groups, affording various phosphachromones by the simultaneous formation of C-P and C-O bonds in one step with moderate to good yields, and the Fries rearrangement involving phosphorus atoms is a key step in the reaction.

Ribbon-shaped supramolecular solvents: Synthesis, characterization and potential for making greener the microextraction of water organic pollutants

Liquid-liquid microextraction (LLME) techniques have experienced a tremendous growth over the last years but still face major challenges related to the use of more efficient and environmentally friendly solvents. Supramolecular solvents (SUPRASs) have proved outstanding efficiency in LLME, but many of the experimental conditions required for SUPRAS formation and/or application cannot be considered green or experimentally convenient. This paper was intended to make greener both SUPRAS formation and their application to the LLME of low-concentration organic pollutants in environmental waters. For this purpose, a variety of SUPRASs were produced at room temperature by simply mixing alkyl phosphonates (A6-12PO3H− and A6-12PO3−2) and tetrahexylammonium (He4N+) ions in aqueous media. Among them, the SUPRASs produced from decyl hydrogen phosphonate (DePO3H−) and He4N+ allowed, for the first time, the development of SUPRAS-based LLMEs where the SUPRAS previously synthesized was added to the liquid sample, instead of being formed in situ as usual, which was proved particularly advantageous for analyses involving large sample/SUPRAS volume ratios. At near equimolar amounts of DePO3H− and He4N+, the amphiphile arranged in the SUPRAS as planar ribbons consisting of water (21 ± 3%, w/v) and DePO3H− and He4N+ in the concentration range 1.0–1.4 M. The application of these SUPRASs to LLMEs was proved by extracting carcinogenic polycyclic aromatic hydrocarbons (CPAHs) from drinking (tap and bottled) and natural (river, reservoir and underground) water (recoveries between 84 and 117% with standard deviations varying between 1 and 14%). The developed method was simple (it only required the addition of 500 μL of SUPRAS to 75 mL of sample, stirring and centrifugation), sensitive (method quantitation limits were below the maximum allowed limits set by the EU; were 0.6–7.1 ng L−1) and selective (SUPRAS extracts were directly analyzed by liquid chromatography-fluorimetry). This research proves that SUPRASs can be operationally used in LLMEs similarly to conventional solvents, which should favor their routine application in high-sample throughput laboratories.

Synthesis and Preliminary Immunological Evaluation of a Pseudotetrasaccharide Related to a Repeating Unit of the Streptococcus pneumoniae Serotype 6A Capsular Polysaccharide.

2-Aminoethyl glycoside of the pseudotetrasaccharide α-d-Glcp-(1→3)-α-l-Rhap-(1→3)-d-Rib-ol-(5-P-2)-α-d-Galp corresponding to a repeating unit of the Streptococcus pneumoniae type 6A capsular polysaccharide has been synthesized. A suitably protected pseudotrisaccharide α-d-Glcp-(1→3)-α-l-Rhap-(1→3)-d-Rib-ol with a free 5-OH group in the ribitol moiety and a 2-OH derivative of 2-trifluoroacetamidoethyl α-d-galactopyranoside have been efficiently prepared and then connected via a phosphate bridge using the hydrogen phosphonate procedure. Preliminary immunological evaluation of this pseudotetrasaccharide and the previously synthesized pseudotetrasaccharide corresponding to a repeating unit of the capsular polysaccharide of S. pneumoniae serotype 6B has shown that they contain epitopes specifically recognized by anti-serogroup 6 antibodies and are able to model well the corresponding capsular polysaccharides. Conjugates of the synthetic pseudotetrasaccharides with bovine serum albumin were shown to be immunogenic in mice.

Isolation and Identification of Pseudo Seven-Coordinate Ru(III) Intermediate Completing the Catalytic Cycle of Ru-bda Type of Water Oxidation Catalysts

Isolation and Identification of Pseudo Seven-Coordinate Ru(III) Intermediate Completing the Catalytic Cycle of Ru-bda Type of Water Oxidation Catalysts

Study of flame retardancy, thermal and physical properties of rigid polyurethane foam based on recycled poly(ethylene terephthalate) using non-halogen flame retardant

Bis(2-hydroxyethyl) terephthalate (BHET) obtained from waste poly(ethylene terephthalate) bottles was used to synthesize polyurethane foams (B-PUF) and the fireproof B-PUF in the presence of nonhalogen flame retardant, namely, aluminum hydrogen phosphonate (AHP). Loading of 25 php AHP was needed for B-PUF/AHP to achieve UL-94 V-0 rating. The thermal stability of B-PUF was improved with the addition of AHP through the thermogravimetric analysis (TGA) results. In addition, other properties such as density and foam structure were also investigated. The outcomes of this study also confirmed that the B-PUF prepared from recycled PET not only were composed of a high percentage of waste poly(ethylene terephthalate), which could help reduce the amount of recycled polymer materials and improved waste management but also met the high demands for the fire safety of polymer applications.

α-Ketophosphonates in the Synthesis of α-iminophosphonates

The potentialities of condensation of α-ketophosphonates with primary amines for direct synthesis of α-iminophosphonates have been revealed. Diesters of α-ketophosphonic acids react with the primary amines by two competitive pathways: with a formation of α-iminophosphonates or a C-P bond cleavage resulting in a hydrogen phosphonate and an acylated amine. In many cases, the latter undesirable pathway is dominant, especially for more nucleophilic alkyl amines. Using metallic salts of α-ketophosphonates avoids the C-P bond cleavage, allowing direct preparation of α-phosphorylated imines by the reaction with primary amines. This strategy provides an atom economy single-stage synthesis of iminophosphonates – precursors of bio relevant phosphorus analogs of α-amino acids. Methyl sodium iminophosphonates, bearing aryl or heteryl substituents at the imino carbon atom exist in solutions at room temperature as an equilibrium mixture of Z- and E-isomers. A configuration of the C=N bond can be controlled by the solvent: changing the aprotic dipolar solvent DMSO-d6 by water or alcohols leads to the change from a predominant Z-isomer to almost an exclusive E-form. In contrast, diesters of the respective iminophosphonates exist in non-protic solvents predominantly in Econfiguration. The solvent effect on E-Z stereochemistry is demonstrated by DFT calculations.

CRYSTAL STRUCTURE OF TRIPHENYLTIN (IV) FORMATE POLYMER, (HCO2SnPh3)n

The title polymer [HCO2Sn(C6H5)3]n was isolated by serendipitous from reaction in ethanol 96 % between bis-(monocyclohexyl ammonium) 2-carboxyethyl hydrogen phosphonate, {(CyNH3)2[CO2CH2CH2PO2(OH)]} and triphenyltin chloride, SnPh3Cl. The polymer crystallizes in the monoclinic space group P21/n with Z = 4, a = 14.7091 (18) Å, b = 15.4133 (19) Å, c = 14.7639 (18) Å, β = 94.242 (2)° and V = 3338.0 (7) Å3. The structure consists of an infinite chain propagating along the crystallographic a-axis direction with bidentate formate anions. The O2SnC3 core is organized into a trans-trigonal bipyramidal like-arrangement.

CRYSTAL STRUCTURES OF TWO PHOSPHONATE SALTS: MONOCYCLOHEXYLAMMONIUM HYDROGEN PHOSPHONATE AND MONOCYCLOHEXYLAMMONIUM PHENYL PHOSPHONATE

Hydrogen phosphonate anions and monocyclohexylammonium cations interacting through hydrogen bonds conduct to the formation of a salt namely monocyclohexylammonium hydrogen phosphonate. In this structure, hydrogen phosphonate anions are linked by pairs through O—H···O hydrogen bonds leading to anionic dimers. Each dimer is connected to its two neighbours through cations via N—H···O hydrogen bonds leading to infinite chains which are then connected by N—H···O hydrogen bonds giving rise to a layered structure. The phenyl phosphonates form dimers that are connected through an expended hydrogen bonding network involving the cations into a layer.

Corrosion Protection of Mild Steel by a New Phosphonated Pyridines Inhibitor System in HCl Solution

The adsorption behavior and inhibition mechanism of (1, 4, 7-Tris [hydrogen (6-methylpyridin-2-yl) phosphonate] -1, 4, 7-triazacyclononane) (TPP) on the corrosion of mild steel in 1 M HCl were investigated by weight loss technique, potentiodynamic polarization, and electrochemical impedance spectroscopy (EIS) methods for different concentrations at 25°C. The results show that the inhibition efficiency values depend on the amount of immersion times and the concentration. A 90% efficiency is found at the highest concentration of the studied compound according to weight loss measurements. The adsorption of the investigated inhibitor on the mild steel surface was well supported using an AFM study. For the assignment of the absorption sites, we performed quantum chemical calculations with (DFT) method. The interaction between the inhibitor and iron surface were performed by molecular dynamic (MD) simulations. In this paper, experimental methods and results used to assess the efficiency of the studied compound are presented.

Electrochemical degradation of diazinon from aqueous media using graphite anode: Effect of parameters, mineralisation, reaction kinetic, degradation pathway and optimisation using central composite design

ABSTRACT In this study, the experimental data were collected in a laboratory-scale batch reactor equipped with a graphite electrode as anode and an SS316 electrode as a cathode. The central composite design (CCD) was selected for evaluation of the effect of different parameters (j = 1–8 mA/cm2, initial diazinon concentration = 30–90 mg/L, pH = 3–11, and electrolysis time = 30–90 min) and their interactions on the electrochemical degradation of the diazinon. The results showed that the degradation of diazinon and removal of COD reached 87.6% and 77.81%, respectively. The kinetic studies were indicative of the suitability of the pseudo-first-order kinetic (R2 > 0.98) for the explanation of data obtained from the degradation of diazinon and removal of COD on the graphite electrode. The AOS parameters in the outlet effluent of the electrochemical process with graphite anode were increased from −0.73 to +0.58, indicating the biodegradability of the diazinon by the electrochemical system. The intermediate produced during the electro-oxidation process were diazinon, O,O-diethyl O-(4-ethylpyrimidin-2-yl) phosphorothioate, O,O-diethyl O-(pyrimidin-2-yl) phosphorothioate, O-methyl O-(pyrimidin-2-yl) O-hydrogen phosphorothioate, O-(pyrimidin-2-yl) O-hydrogen phosphonothioate, pyrimidin-2-yl hydrogen phosphonate, 1,3-dioxan-2-ol, 1λ3,3 λ3-dioxine, and ethane-1,2-diol. Finally, diazinon was completely degraded using hydroxyl radicals produced by the electrochemical process and converted into CO2 and H2O products.

Thermal Properties and Fire Retardancy of Polypropylene/Wood Flour Composites Containing Eco-friendly Flame Retardants

Thermal properties and the flame retardancy of polypropylene/wood flour (PP-WF) composite were improved by adding aluminum hydrogen phosphonate (AHP) and triphenyl phosphate (TPP) flame retardants. PP-WF composites containing 30 wt% of AHP and 30 wt% of TPP achieved UL-94 HB standard with the horizontal burning rate of 20.8 mm/min and of 11.5 mm/min, respectively. Thermal properties of PP-WF composite with and without flame retardant, as well as the interaction between PP-WF and flame retardant were investigated through TGA analysis. The flame retardant mechanism is mainly in condensed phase for AHP and in gas phase for TPP. The residual char after the decomposition of PP-WF/AHP composite was analyzed by FTIR to understand how the formation of char affected on the flame retardancy and thermal stability PP-WF composite.

Synthesis, Characterization and Evaluation of Cytotoxic Activities of Novel Aziridinyl Phosphonic Acid Derivatives.

New aziridine 2-phosphonic acids were prepared by monohydrolysis of the aziridine 2-phosphonates that were obtained by the modified Gabriel-Cromwell reaction of vinyl phosphonate or α-tosylvinyl phosphonate with a primary amine or a chiral amine. The cellular cytotoxicity of these compounds was tested against the HCT-116 colorectal cancer cell lines and the CCD-18Co normal colon fibroblast lines using the MTT assay. Three of the synthesized phosphonic acid derivatives 2e (ethyl hydrogen {(2S)-1-[(1S)-1-(naphthalen-2-yl)ethyl]aziridin-2-yl}phosphonate), 2h (ethyl hydrogen (1-benzylaziridin-2-yl)phosphonate), and 2i (ethyl hydrogen (1-cyclohexylaziridin-2-yl)phosphonate) showed higher cytotoxicity than the reference cancer treatment agent etoposide. Cell death was through a robust induction of apoptosis even more effectively than etoposide, a well-known apoptosis inducing agent.

Fireproof behavior of polyurethane foam based on waste poly(ethylene terephthalate) using aluminum hydrogen phosphonate flame retardant

Poly(ethylene terephthalate) is a widely used polymer in the blow molding bottles, electron industry, texiile industry and can be recycled to synthesize new materials such as polyurethane foam (PUf) and unsaturated polyester (UP). One of them, PUf has many desirable properties such as low thermal conductivity, low density, excellent dimensional stability, high strength-to-weight ratio, low moisture permeability and low water absorption. However, PUf is a highly flammable material. In this study, aluminum hydrogen phosphonate (AHP) was synthesized in order to investigate their flame retarding performances for PUf. UL-94 V-1 was obtained at 15 phr loading of AHP. The incorporation of flame retardant increased the fireresistant property of PUf. In addition, other properties such as density, foam structure, and water and moisture absorption were also investigated.

Formation of Mono- and Polynuclear Luminescent Lanthanide Complexes based on the Coordination of Preorganized Phosphonated Pyridines.

A series of polynuclear assemblies based on ligand L (1,4,7-tris[hydrogen (6-methylpyridin-2-yl)phosphonate]-1,4,7-triazacyclononane) has been developed. The coordination properties of ligand L with LnIII (Ln = La, Eu, Tb, Yb, Lu) have been studied in water (pH = 7.0) and in D2O (pD = 7.0) by UV-absorption spectrometry, spectrofluorimetry, 1H and 31P NMR, DOSY, ESI-mass spectrometry, and X-ray diffraction. This nonadentate ligand forms highly stable mononuclear complexes in water and provides a very efficient shielding of the Ln cations, as emphasized by the very good luminescence properties of the Yb complex in D2O, especially regarding its lifetime (τD2O = 10.2 μs) and quantum yield (ϕD2O = 0.42%). In the presence of excess LnIII cation, polynuclar complexes of [(LnL)2Ln x] stoichiometry (x = 1 and x = 2) are observed in solution. In the solid state, a dinuclear complex of La could be isolated and structurally characterized by X-ray diffraction, unraveling the presence of strong hydrogen bonding interactions between a La(H2O)93+ cation and the [LaL]3- complex.

Tuning Intrinsic and Extrinsic Proton Conduction in Metal-Organic Frameworks by the Lanthanide Contraction.

Seven isomorphous lanthanide metal-organic frameworks in the PCMOF-5 family, [Ln(H5L)(H2O)n](H2O) (L = 1,2,4,5-tetrakis(phosphonomethyl)benzene, Ln = La, Ce, Pr, Nd, Sm, Eu, Gd) have been synthesized and characterized. This family contains 1-D water-filled channels lined with free hydrogen phosphonate groups and gives a very low activation energy pathway for proton transfer. The lanthanide contraction was employed to systematically vary the unit cell dimensions and tune the proton conducting pathways. LeBail fitting of the crystalline series shows that the crystallographic a-axis, along the channel, can be varied in increments less than 0.02 Å correspondingly shortening the proton transfer pathway. The proton conductivities for the La and Pr complexes were roughly an order of magnitude higher than other members of the series (10-3 S cm-1 versus 10-4 S cm-1). Single crystal structures of the high and low conducting members of the series (La, Pr for high and Ce for low) affirm the structural similarities extend beyond the unit cell parameters to positions of free acid groups and included water molecules. Scanning electron microscopy reveals marked differences in particle size of the different members of the Ln series owing to lattice strain effects induced by changing the lanthanide. Notably, the high conducting La and Pr complexes have the largest particle sizes. This result contradicts any notion that degradation of the MOF at grain boundaries is enabling the observed conductivity as proton conduction dominated by extrinsic pathways would be enabled by small particles (i.e., the La and Pr complexes would be the worst conductors). Proton conductivity measurements of a ball milled sample of the La complex corroborate this result.

Hydrogen bonds and van der Waals forces as tools for the construction of a herringbone pattern in the crystal structure of hexane-1,6-diaminium hexane-1,6-diyl bis-(hydrogen phospho-nate).

The asymmetric unit of the title salt, [H3N(CH2)6NH3][(HO)O2P(CH2)6PO2(OH)], consists of one half of a hexane-1,6-diaminium dication and one half of a hexane-1,6-diyl bis-(hydrogen phospho-nate) dianion. Both are located around different centres of inversion (Wyckoff sites: 2a and 2d) of the space group P21/c. The shape of the hexane-1,6-diaminium cation is best described as a double hook. Both aminium groups as well as the two attached CH2 groups are turned out from the plane of the central four C atoms. In contrast, all six C atoms of the dianion are almost in a plane. The hydrogen phospho-nate (-PO3H) groups of the anions and the aminium groups of the cations form two-dimensional O-H⋯ and O-H⋯N hydrogen-bonded networks parallel to the ac plane, built up from ten-membered and twelve-membered ring motifs with graph-set descriptors R33(10) and R54(12), respectively. These networks are linked by the alkyl-ene chains of the anions and cations. The resulting three-dimensional network shows a herringbone pattern, which resembles the parent structures 1,6-di-amino-hexane and hexane-1,6-di-phospho-nic acid.

Mediating Order and Modulating Porosity by Controlled Hydrolysis in a Phosphonate Monoester Metal–Organic Framework

A crystalline and permanently porous copper phosphonate monoester framework has been synthesized from a tetraaryl trigonal phosphonate monoester linker. This material has a surface area over 1000 m2 g-1 , as measured by N2 sorption, the highest reported for a phosphonate-based metal-organic framework (MOF). The monoesters result in hydrophobic pore surfaces that give a low heat of adsorption for CO2 and low calculated selectivity for CO2 over N2 and CH4 in binary mixtures. By careful manipulation of synthetic conditions, it is possible to selectively remove some of the monoesters lining the pore to form a hydrogen phosphonate while giving an isomorphous structure. This increases the affinity of the framework for CO2 giving higher ambient uptake, higher heat of adsorption, and much higher calculated selectivity for CO2 over both N2 and CH4 . Formation of the acid groups is noteworthy as complexation with the parent acid gives a different structure.