Organic Diluents Research Articles

Chemical and mechanistic modelling of green solvent extraction of metallic species with 4-acylpyrazolones

Solvent extraction chemistry of metals needs the use of suitable organic ligands like 4-acylpyrazolones to coordinate the studied cation, to make it soluble in an organic phase and then allow its phase transfer from the aqueous phase. The competitive solvent extraction test of almost 25 metal ions by one powerful ligand, i.e. 3-methyl-1-phenyl-4-(4-trifluoromethylbenzoyl)-pyrazol-5-one diluted in one ionic liquid ([C1Cnim+][Tf2N−]) has been conducted to get a snapshot of its efficacy. Effect of diluents on the liquid–liquid extraction of 4f-ions with a series of chelating ligands of 4-acylpyrazolones family (∼5) is presented comparing ionic liquids and typical organic diluents: 14 in number. In addition, the solvent extraction of 12 refractory metals with a series of chelating extractants is investigated in five diluents: four 4-acylpyrazolones with different radicals. The solvent extraction stoichiometry of MoO42− and Zr4+ is studied in detail using molecular and ionic diluent for comparative purposes through slope analysis method. Ethylene glycol is used to develop a non-aqueous process for Gd3+ switchable extraction, i.e. boost of two immiscible organic phases. Furthermore, EPR, NMR, IR and DTA-TG-MS spectroscopies have been used to study the extracted d- and f-species in the obtained organic extracts in ionic liquid solutions.

Utilizing environment-friendly eugenol as a diluent with trioctylamine for the reactive extraction of aqueous levulinic acid

This paper focuses on the reactive extraction of levulinic acid (LA) from aqueous solution by reactive extraction. This goal is achieved using eugenol, a green alternative in the industry, as a solvent in the liquid-liquid equilibrium (LLE) measurements for the ternary system of LA + Eugenol + H2O and quaternary systems of LA + Eugenol/ Methanol (MeOH) + H2O + Tri-n-octylamine (TOA) at T = 293.15 K. Additionally, the distribution coefficients (KD) were calculated for LA using the two diluents. Also, the ability of different diluents with TOA, in the extraction of LA were compared. The distribution coefficient of eugenol with TOA (KD = 9.44) is compared with other organic diluents which indicated that eugenol is a suitable option. MeOH, being the shortest chain alcohol, also turned out to be a diluent that could be utilized for extraction of LA with TOA. Furthermore, the Non-Random Two-Liquid (NRTL) excess Gibbs energy model was applied to correlate the measured phase equilibria. The obtained parameters were further validated using a decanter model.

Electrochemical CO2 Reduction in Deep Eutectic Solvent: Effect of Water and Organic Diluents

Electrochemical CO₂ Reduction in Deep Eutectic Solvent: Effect of Water and Organic Diluents

Reactive extraction of muconic acid by hydrophobic phosphonium ionic liquids - Experimental, modelling and optimisation with Artificial Neural Networks

Muconic acid is a six-carbon dicarboxylic acid with conjugated double bonds that finds extensive use in the food (additive), chemical (production of adipic acid, monomer for functional resins and bio-plastics), and pharmaceutical sectors. The biosynthesis of muconic acid has been the subject of recent industrial and scientific attention. However, because of its low concentration in aqueous solutions and high purity requirement, downstream separation presents a significant problem. Artificial Neural Networks and Differential Evolution were used to optimize process parameters for the recovery of muconic acid from aqueous streams in a system with n-heptane as an organic diluent and ionic liquids as extractants. The system using 120 g/L tri-hexyl-tetra-decyl-phosphonium decanoate dissolved in n-heptane, pH of the aqueous phase 3, 20 min contact time, and 45 °C temperature assured a muconic acid extraction efficiency of 99,24 %. Low stripping efficiency compared to extraction efficiency was observed for the optimum conditions on the extraction step (120 g/L ionic liquids dissolved in heptane). However, re-extraction efficiencies obtained for the recycled organic phase in three consecutive stages were close to the first extraction stage. The mechanism analysis proved that the analysed phosphonium ionic liquids (PILSs) extracts only undissociated molecules of muconic acid through H-bonding.

Extraction Equilibria in the Samarium Nitrate–Nitric Acid–Water–Di(2-ethylhexyl)phosphoric Acid–Organic Diluent System

Extraction Equilibria in the Samarium Nitrate–Nitric Acid–Water–Di(2-ethylhexyl)phosphoric Acid–Organic Diluent System

Eco-Friendly Approach for the Recovery of Lactic Acid by Complex Extraction.

To meet the growing demand for high-purity lactic acid (LA) for biocompatible and biodegradable polymers, LA recovery by green techniques has been attracting the attention. This study focuses on the evaluation of vegetable oils as organic phase diluents in complex extraction of LA with an aliphatic tertiary amine extractant, trioctylamine (TOA). Eight vegetable oils were tested, and their performances were evaluated individually and compared with those obtained using 1-octanol. Extraction yields with these oils were similar; however, efficiencies with safflower oil (SFO) were slightly higher than those obtained with other oils tested. Efficiency with SFO + TOA varied inversely with temperature and pH; however, it increased with higher LA and TOA concentrations. Within the ranges of parameters investigated, the highest yield in SFO was 66% and was achieved at the highest TOA (1.0 M) and LA (1.5 M) concentrations. The efficiency obtained in 1-octanol under the identical conditions was 76%. Thus, the yields obtained with SFO + TOA and 1-octanol + TOA were comparable under most of the conditions tested, especially at the higher LA concentrations, which is preferred for commercial production. Following that, >99% of the LA was transferred from the organic phase to the (second) aqueous phase using NaOH (1.0 M) as a stripping agent. The organic phase was tested in subsequent extractions, and yields comparable to those obtained in the first uses were achieved. This study demonstrated that vegetable oils have the potential to be used as organic phase diluents during complex extraction of LA.

Regulating the absorption and solid regeneration performance of a novel anhydrous solid–liquid phase change absorbent for carbon capture

The solid–liquid biphasic solvent has great energy-saving potential, but its absorption rate and solid regeneration performance need to be improved. In this study, a new solid–liquid biphasic solvent was proposed using 1,3-diaminopropane (DAP) as the main absorbent, 2-amino-2-methyl-1-propanol (AMP) and piperazine (PZ) as the absorption enhancer, and n-propanol (NPA) as the organic diluent and regeneration promoter. AMP and PZ could boost the CO2 absorption and thus shorten the absorption saturation time from 120 min to 80 and 60 min, and further reduce the regeneration energy to 1.30 and 1.35 GJ·t−1 CO2 as well. They were much lower than the reported biphasic absorbents and only 34.2 % and 35.6 % of the 3.80 GJ·t−1 CO2 produced by 5 M MEA. Moreover, adding a small amount of NPA to the lower phase could significantly increase the desorption efficiency to 84.5 %, whereas no CO2 was desorbed without the help of NPA. Experimental and theoretical analysis indicated that during CO2 absorption, the DAP-NPA system absorbed CO2 to produce DAPCOO- and protonated DAP. Adding AMP or PZ to the system enhanced product coupling by replacing DAPCOO- with a small amount of AMPCOO- or PZCOO-, thereby accelerating the reaction. Furthermore, during regeneration, NPA would weaken the hydrogen bonding between the products and promote the CO2 desorption and the regeneration of solid products. This work developed a promising solid–liquid biphasic solvent with good comprehensive performance.

Nanoporous hypercrosslinked polymers as cost-effective catalysts to significantly promote the CO2 absorption performance of water-lean solvents for post-combustion CO2 capture

In most cases, the slow CO2 sorption kinetics of water-lean solvents—which include low-volatile organic diluents—are the limiting factor when it comes to post-combustion CO2 capture. This study offers a solution by suggesting the use of catalysts based on nanoporous hypercrosslinked polymers (HCPs) to improve the removal efficiency of water-lean solvents based on diethanolamine (DEA) and to increase CO2 mass transfer. Simple and inexpensive monomers were used to prepare three HCPs: HCP-C, HCP-S, and HCP-B, which stand for benzene, polystyrene, and carbazole, respectively. Blends of DEA and Glycerol (Gly) were used to disperse these polymers. Addition of 0.5 wt% HCP to a solvent mixture of 20% DEA and 30% Gly considerably boosts removal efficiency and increases the amount of CO₂ that can be absorbed until the breakthrough point by as much as 3000%, according to the results. Additionally, various gas flow rates, DEA concentrations, and glycerol concentrations were also investigated to determine the HCP-C catalytic effect on the CO2 absorption. A volumetric overall mass transfer coefficient enhancement of up to 319 % is possible in the investigated ranges when using HCP-C, according to the findings. Moreover, a possible catalytic mechanism was suggested.

Bioderived Pickering Emulsion Based on Chitosan/Trialkyl Phosphine Oxides Applied to Selective Recovery of Rare Earth Elements.

A novel biobased pickering emulsion (PE) material was prepared by the encapsulation of Cyanex 923 (Cy923) into chitosan (CS) to selectively recover rare earth elements (REEs) from the aqueous phase. The preparation of PE was optimized through sequentially applying a 23 full factorial design, followed by a 33 Box-Behnken design varying the Cy923 content, CS concentration, and pH of CS. The material was characterized by Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), optical microscopy, rheological, compositional, and stability measurements. The resultant material was evaluated in the removal of yttrium by pH influence, nitrate concentration, kinetics, equilibrium isotherms, reusability, and a comparison with liquid-liquid (L-L) extraction and tested in a real scenario to extract Y from a fluorescent lamp powder waste. In addition, the selectivity of PE for REE was investigated with Y/Ca, Gd/Ca, and La/Ni systems. PE extracts REE at 1 ≤ pH ≤ 5 at nitrate concentrations up to 2 mol/L. The kinetics and equilibrium studies showed reaction times <5 min and a maximum sorption capacity of 89.98 mg/g. Compared with L-L extraction, PE consumed 48% less Cy923 without using organic diluents. PE showed a remarkable selectivity for REE in the systems evaluated, showing separation factors of 22.62, 9.35, and 504.64 for the blends Y/Ca, Gd/Ca/Mg, and La/Ni, respectively. PE showed excellent selectivity extracting Y from a real aqueous liquor from the fluorescent lamp powder. PE demonstrates to be an effective and sustainable alternative for REE recovering due to its excellent efficiency in harsh conditions, favorable green chemistry metrics, and use of a biopolymer material in its composition avoiding the use of organic solvents used in L-L extraction.

New Sustainable Solvent Extraction Pathways for Rare Earth Metals via Oximes Molecules.

A study on the synergistic extraction of Eu(III) ions with a series of chelating ligands and determination of the process parameters is presented by employing ionic liquids and typical organic diluents. The investigations of the liquid-liquid extraction, commonly applied in the separation science of 4f and 5f-ions acidic chelating compounds, 4-benzoyl-3-methyl-1-phenyl-2-pyrazolin-5-one (HP), 4-benzoyl-3-phenyl-5-isoxazolone (HPBI), and 2-thenoyltrifluoroacetone (HTTA) alone and in combination with two synergistic agents, meso-hexamethylpropyleneamine oxime (S2: HM-PAO) and its bis-imine precursor (S1: pre-HM-PAO), are presented. The interaction between the two extractants (acidic/neutral) in deuterochloroform was studied using 1H, 13C, and 1H-1H NOESY experiments. Several conclusions are given highlighting the role of the ionic diluent in complexation processes and selectivity with an employment of the two synergistic agents for various metal s-, p-, d-, and f-cations in the Periodic table, with almost 25 metal ions. The objective was to optimize a system for 4f-ions solvent extraction based on the new oxime molecules with β-diketone/isoxazolone/pyrazolone partnership. As detailed above, slight enhancements of extraction efficiencies were obtained either by using basic synergistic agents such as HM-PAO and/or using pre-HM-PAO. A competitive solvent extraction test of nearly 18 f-ions by various ligands (HTTA, S1, S2, and HPBI) and the two mixtures HTTA-S1 and HTTA-S2 diluted in ILs or organic diluents was also conducted in order to evaluate the switchable diluent impact. Additionally, electron paramagnetic resonance (EPR) spectroscopy was used to study the established chemical species with Cu2+ cations in the obtained organic extracts involving the two synergistic molecules.

Synergistic Extraction of Lanthanides(III) from Acidic Aqueous Solutions with Mixtures of Bis(Diphenylcarbamoylmethylphosphine Oxide) Ligands and Dinonylnaphtalene Sulfonic Acid

ABSTRACT The extraction of lanthanides(III) from aqueous nitric acid solutions with mixtures of bis(diphenylcarbamoylmethylphosphine oxides) (L) and dinonylnaphthalene sulfonic acid (HDNNS) in organic diluents is studied. It is established that the efficiency of extraction of Ln(III) ions increases significantly when HDNNS is added to the organic phase containing L. The synergistic effect arises due to the higher hydrophobicity of the extractable Ln(III) complexes formed by the L ligand and DNNS− anions compared to those containing NO3 − ions as counteranions. The stoichiometry of the extracted complexes is determined, and the influence of the composition of the aqueous phase, the nature of the organic solvent, and the structure of the bis-CMPO ligands on the efficiency of the extraction of metal ions into the organic phase is considered. The synergistic effect during the extraction of Ln(III) from aqueous nitric acid solutions with mixtures of L and HDNNS weakens with increasing the acidity of the aqueous phase; however, it also holds in acidic media.

Extraction of cadmium from aqueous solutions by emulsion liquid membrane (ELM) using three different carriers dissolved in a 70:30 ratio of sunflower oil to kerosene

This study explores the use of novel green emulation liquid membranes (GELMs) for the simultaneous extraction and stripping of Cd (II) from aqueous solutions. A solute is transported through the membrane due to the presence of the carrier and then concentrated in the internal phase. Soybean, sunflower, corn, and canola oils were used to form green substitutes to petroleum-based organic diluents for use as GELMs. Bis-(2-ethylhexyl) phosphate (D2EHPA), tri-butyl- phosphate (TBP), and trioctylamine (TOA) were the extractants, span 80 was the emulsifier, and HCl or H2SO4 was used as the stripping agent. The best conditions for maximum extraction efficiency (98.68%), stripping efficiency (97.14%), and lowest membrane breakage (0.9%) were achieved using a mixture of sunflower oil and kerosene in the ratio of 70:30. The other optimum values of the variables were: 2% (v/v) Span 80, 10 min emulsification time, 12700 rpm emulsification speed, 400 rpm of agitation speed, 5% (v/v) D2EHPA, an external phase pH was 3.5, an internal phase of 0.25 M HCl, and 5:1 of the treat ratio (external phase to emulsion) at 10 min contact time. The synthesized membrane was reused eight times, with approximately the same efficiency and no significant breakage during the first seven cycles.

The Aptness of Organic Diluents with Tri‐n‐Butyl Phosphate for Liquid‐Liquid Equilibria of Acrylic Acid

AbstractSeparation of carboxylic acids from downstream is a bottleneck in the chemical industry since it takes nearly 30–50 % of the overall production cost. In view of this, an attempt was made for the extraction of acrylic acid from aqueous solution with tri‐n‐butyl phosphate dissolved in organic diluents like benzene, toluene, xylene, hexane, and petroleum ether. The results are explained in terms of distribution coefficient (σ), extraction efficacy (η%), equilibrium complexation constant (Kε), loading ratio (ϕ), and coextraction of water. At lower concentration of acrylic acid and higher concentration of tri‐n‐butyl phosphate for the acrylic acid‐tri‐n‐butyl phosphate system, maximum extraction efficacy and distribution coefficient for benzene was found as 88.60 % and 7.772, respectively. Coextraction of water in the extract phase and law of mass action were discussed, too. Diffusivity of acrylic acid to the interface of extract (organic) and raffinate (aqueous) phases was calculated using the Wilke‐Chang equation and Reddy‐Doraiswamy equation. In view of designing a continuous extraction column, the number of theoretical stages and minimum solvent‐to‐feed ratio were also determined.

Evaluation of the remaining spent extraction solvent in vermiculite after leaching tests via PIXE analysis

The spent extraction solvent, primarily comprising tributyl phosphate (TBP) and normal dodecane, is waste product generated by the solvent extraction of plutonium and uranium to develop the plutonium–uranium redox-extraction process. The spent solvent should be appropriately treated for disposal or storage. One treatment option for storing the spent solvent is the adsorption of the liquid into vermiculite. The organic liquid is trapped between the vermiculite layers. Our previous experiments on the adsorption of spent solvent into vermiculite have shown that some parts of the loaded solvent gradually leaked from the vermiculite. Therefore, the elution behavior of the loaded solvent into organic diluents, such as hexane or acetone, were evaluated to investigate the adsorption mechanism and capacity. Some loaded solvents easily leaked into the diluent, whereas some remained inside the particle, even after the leaching test. The difference in behavior might be attributed to different adsorption mechanisms, and the amount of the remaining solvent is the adsorption capacity for safely storing the solvent. This study evaluated the vermiculite adsorption capacity via the remaining solvent after washing with diluents, such as ethanol or distilled water. The remaining solvent was analyzed using particle-induced X-ray emission (PIXE) on phosphorous (P) contained in the TBP. PIXE analysis quantitatively analyzed the trace amounts of residual TBP, and n-dodecane and TBP were suggested to be adsorbed to vermiculite by different mechanisms.

Mutual Solubilities between Ethylene Glycol and Organic Diluents: Gas Chromatography and NMR.

In this work, the mutual solubilities of sets of organic diluents (CHCl3, C6H6, C2H4Cl2, CCl4, C6H12, and n-hexane) with the organic compound ethylene glycol are investigated via gas chromatography (GC). The experimental data measured for these binary organic systems are used to adjust the future nonaqueous systems for the solvent extraction of various metals with ligands. The obtained results showed that the solubility of ethylene glycol decreased in the order CHCl3 > C6H6 > C2H4Cl2 > CCl4(0%) ≈ C6H12 ≈ n-hexane. On the other hand, the solubility of the tested traditional organic diluents in ethylene glycol decreased in the following order: C6H6 > CHCl3 > C2H4Cl2 > n-hexane > C6H12 > CCl4. 1H NMR was also used as an analytic method in order to compare the obtained results for the samples showing significant solubility only, including an additional study with 1,2- or 1,3-propanediol. The enhanced solubility of the C6H6 compound in ethylene glycol was identified here as critical due to the GC technique, which will be without future consequences in chemical technology. Therefore, it was found that the best molecular diluent for the recovery of metals among the tested ones is C6H12, with a green protocol as the new paradigm, replacing the aqueous phase with another nonaqueous phase, i.e., a second organic diluent.

Solid acid catalysts for low-temperature regeneration of non-aqueous sorbents: An innovative technique for energy-efficient CO2 capture processes

Chemical absorption of CO2 from flue gases by using aqueous amine sorbents is regarded as the most mature and effective technology for reducing CO2 emissions, but the high energy cost of sorbent regeneration has so far greatly limited its industrial application. One of the best strategies developed by researchers in recent years to reduce energy requirements is to improve CO2 desorption kinetics by adding catalysts during sorbent regeneration. Moreover, non-aqueous sorbents have recently been gaining increasing attention as alternatives to conventional aqueous amines as they have the potential to lower the energy demand for sorbent regeneration. In this paper, we propose an innovative technique that combines and further develops these two emerging technologies, non-aqueous absorbent and catalyst-assisted regeneration, to enable less energy-intensive CO2 capture processes. In particular, in this screening study, we evaluate the regeneration behaviour of a CO2-saturated solution of 2-(2-aminoethoxy)ethanol (DGA) in diethylene glycol monomethyl ether (DEGMME) when heated to 85 °C in the absence and presence of different types of solid acid catalysts. In order to assess the potential benefits of this innovative technique over conventional systems, the results obtained were compared with the desorption performance of an aqueous solution of DGA under the same operating conditions and with the same catalysts, which highlighted the possibility of obtaining rapid desorption at relatively low temperatures when conducted with suitable acid catalysts using amines in organic diluents.

Microscopic-Level Insights into Solvation Chemistry for Nonsolvating Diluents Enabling High-Voltage/Rate Aqueous Supercapacitors.

Localized "water-in-salt" (LWIS) electrolytes are promising candidates for the next generation of high-voltage aqueous electrolytes with low viscosity/salt beyond high-salt electrolytes. An effective yet high-function diluent mainly determines the properties of LWIS electrolytes, being a key issue. Herein, the donor number of solvents is identified to serve as a descriptor of interaction intensity between solvents and salts to screen the organic diluents having few impacts on the solvation microenvironment and intrinsic properties of the original high-salt electrolyte, further leading to the construction of a novel low-viscosity electrolyte with a low dosage of the LiNO3 salt and well-kept intrinsic Li+-NO3--H2O clusters. Nonsolvating diluents, especially acetonitrile (AN) that has never been reported previously, are presented with the capability of constructing a LWIS electrolyte with nonflammability, electrode-philic features, lower viscosity, decreased salt dosage, and a greatly enhanced ion diffusion coefficient by about 280 times. This strongly relies on a huge difference of about 5000 times in coordination and solubility between AN and H2O toward LiNO3 (0.05 vs 25 mol kgsolvent-1) and the moderate interaction between AN and H2O. Multi-spectroscopic techniques and molecular dynamics simulations uncover the solvation chemistry at the microscopic level and the interplay among cations, anions, and H2O without/with AN. The identified unique diluting and nonsolvating effects of AN reveal well-maintained cation-anion-H2O clusters and enhanced intermolecular hydrogen bonding between AN and H2O, further reinforcing the H2O stability and expanding the voltage window up to 3.28 V. This is a breakthrough that is far beyond high-viscosity/salt electrolytes for high-voltage and high-rate aqueous supercapacitors.

Extraction of Lanthanides(III) from Aqueous Nitric Acid Solutions with Tetra(n-octyl)diglycolamide into Methyltrioctylammonium Bis(trifluoromethanesulfonul)imide Ionic Liquid and Its Mixtures with Molecular Organic Diluents

The extraction of lanthanides(III) from aqueous nitric acid solutions with tetra(n-octyl)diglycolamide into methyltrioctylammonium bis(trifluoromethanesulfonul)imide ([N1888][Tf2N]) ionic liquid and its mixtures with molecular organic diluents is investigated in this study. This study also investigates the effect of HNO3 concentration in the aqueous phase on the extraction of Ln(III) ions. Subsequently, the stoichiometry of the extracted complexes is determined, and the mechanism of Ln(III) extraction in a system with [N1888][Tf2N] is discussed. It is shown that the intragroup selectivity of the extraction of Ln(III) ions is significantly higher when using [N1888][Tf2N] than when using the imidazolium-based ionic liquid [C4mim][Tf2N].

Using eco-friendly alternatives for the recovery of pyruvic acid by reactive extraction

Efficiency, cost and environmental impact are important parameters that must be addressed in the recovery and purification of pyruvic acid (PA) from fermentation media. In this study, twelve vegetable oils were evaluated with three extraction agents for the reactive extraction of PA. Recoveries with trioctylamine (TOA) were significantly higher than those with tributylphosphate (TBP) and trioctylmethylammonium chloride (TOMAC). The reactive extraction yields with vegetable oils were similar and comparable to that with 1-octanol; among the tested oils, the highest efficiencies were achieved with almond oil. Efficiencies increased with higher extractant amounts, but were negatively affected by higher pH and PA concentrations. Higher temperatures caused slight negative effects on yields. Loading ratios (z) showed that 1:1 PA:Ext complexes most probably occur with all extractants tested; moreover, 2:1 PA:TOA may form due to the z values > 1 with TOA. The PA was stripped and organic phase was regenerated after two consecutive back extraction steps using 2.5 M NaNO3. Organic phases could be re-used 5 times with only a 1–2% decline in efficiency. Based on the performance parameters evaluated and extraction yields obtained, vegetable oils have the potential for use as organic phase diluents during reactive extraction of PA.

EXTRACTION OF LIGHT GROUP LANTHANIDE NITRATES BY A BINARY EXTRACTANT BASED ON DI-(2-ETHYLHEXYL)PHOSPHORIC ACID AND TRIOCTYLAMINE

The process of extracting the light group lanthanide nitrates from neutral aqueous solutions with a binary extractant based on di-(2-ethylhexyl)phosphoric acid (HA), tri-n-octylamine (NR3) and solvating additive of tri-n-octylamine nitrate in a non-polar organic diluent was investigated in this study. Using neodymium nitrate as an example, it was shown that this extractant (NR3HA+NR3HNO3) extracts Ln(NO3)3 according to the laws of binary extraction. The cation and anion of the inorganic salt pass into the organic phase in a stoichiometric ratio. The extraction isotherms of lanthanide nitrates are S shape, and only slight variation of pH is observed during the extraction. Based on the study of the absorption spectra of Nd complexes in the organic phase, it was found that at low concentration the Nd form a complex (NdA3)•NR3HNO3, and at a high concentration of Nd (when the extraction is saturated), a compound of the composition (NdA2NO3)•NR3HNO3 is formed. The introduction of salting-out agents in the aqueous phase or the organic phase makes it possible to vary the distribution coefficients (DNd). With an increase in the concentration of sodium nitrate in the aqueous phase, DNd increases, and with an increase in the concentration of NR3HNO3, it correspondingly decreases. The introduction of the salting-out and solvating agent NR3HNO3 into the organic phase eliminates the formation of precipitation in the organic phase during the extraction of lanthanide nitrates. Quantitatively, the Nd extraction process in a wide range of Nd(NO3)3 concentrations and extractant compositions can be described on the basis of two coupled binary extraction equations and the corresponding concentration constants. It has been established that the proposed extractant provides high separation factors for neodymium and other light group lanthanides.