Extractive Desulfurization of Fuel Oils with Dicyano(nitroso)methanide-based Ionic Liquids

The inability of traditional hydrodesulfurization (HDS) to effectively remove aromatic sulfur compounds such as thiophene (TS) and dibenzothiophene (DBT) has called for alternative methods to be studied, among which extractive desulfurization using ionic liquids (ILs) has attracted increasing interest. In this work, we prepared a new IL, 1-butyl-3-methylimidazolium dicyano(nitroso)methanide ([C₄mim][dcnm]), and investigated its extractive desulfurization for both model oils and real FCC gasoline, where model diesel fuel was composed of n-hexane and droplets of DBT and model gasoline was composed of n-hexane, toluene and droplets of TS. Other three [dcnm]-based ILs, 1-ethyl-3-methylimidazolium dicyano(nitroso)methanide ([C₂min][dcnm]), N-ethyl-N-methylpyrrolidinium dicyano(nitroso)methanide ([C₂mpyr][dcnm]), and N-butyl-N-methylpyrrolidinium dicyano(nitroso)methanide ([C₄mpyr][dcnm]), were also comparatively investigated. These [dcnm]-based ILs have low viscosity which favors the mass transfer and reduces the extractive equilibrium time, also are fluorine-free which avoids the corrosion by hydrogen fluoride from anion decomposition that occurs generally in fluorine-containing ILs. The desulfurization ability follows the order [C₄min][dcnm] > [C₄mpyr][dcnm] > [C₂min][dcnm] > [C₂mpyr][dcnm]. Typically, [C₄min][dcnm] is capable of removing 66% DBT and 53% TS from their respective model oils after one cycle (initial 500 ppm S, 25°C, 15 min, mass ratio of IL:oil 1:1), and < 10 ppm S-content can be obtained after 4 cycles. It was observed interestingly that the S-content in real FCC gasoline can be reduced from initial 250 ppm to < 30 ppm after 6 cycles using [C₄min][dcnm] as extractive reagent, which is better than some previous results for real feedstocks. Mutual solubility, extractive temperature, IL:oil mass ratio, multiple extraction, initial S-content, and regeneration were also studied. These dcnm-based ILs are competitive extractive reagents compared with some other ILs to remove those aromatic S-compounds from fuel oils.     

Reverse atom transfer radical polymerization of methyl methacrylate in imidazolium ionic liquids

Reverse atom transfer radical polymerization (ATRP) of methyl methacrylate (MMA) employing 2,2-azobisisobutyronitrile (AIBN)/CuCl₂/bipyridine(bipy) as the initiating system was approached at 80 °C in two ionic liquids, 1-butyl-3-methylimidazolium tetrafluoroborate ([C₄mim][BF₄]) and 1-dodecyl-3-methylimidazolium tetrafluoroborate ([C₁₂mim][BF₄]), respectively. The polymerization in [C₁₂mim][BF₄] proceeded in a well-controlled manner as evidenced by kinetic studies, end group analysis, chain extension, and block copolymerization results, but not in [C₄mim][BF₄] presumably due to poor solubility of PMMA in it. The kinetic study of reverse ATRP of MMA in recycled [C₁₂mim][BF₄] suggested that this ionic liquid could be re-used as reaction solvent after simple purification, without affecting the living nature of polymerization.     

四氟硼酸盐类离子液体对典型柴油的萃取脱硫研究

The extractive removal of sulfur compounds （S-compounds） from Dongying and Liaohe diesel fuels with [BF4]^--based ionic liquids were systematically investigated. The results show that the absorption capacity of an ionic liquid for the S-compounds in diesel fuels relies on its structure and its size. In the case of the two examined diesel fuels, both elongating the cation tail length and increasing the mass ratio of ionic liquid/diesel fuel promote the desulfurization ability of the examined ionic liquids. The results also show that imidazolium-based ionic liquids display higher extraction efficiencies than pyridinium-based ionic liquids, presumably owing to the fact that the rings of the S-compounds are similar to the imidazolium head ring. With the 1 ： 1 mass ratio of ionic liquid/diesel fuel, the rates of the first desulfurization of Dongying and Liaohe diesel fuels using [C8mim][BF4] amount to 29.96% and 39.76%, suggesting that [C8mim][BF4] is a promising extractant for desulfurization of these diesel fuels.     

Extractive Desulfurization of Fuel Oils with Thiazolium-Based Ionic Liquids

A new class of green solvents, known as ionic liquids (ILs), has recently been the subject of intensive research on the extractive desulfurization of fuel oils because of the limitation of the traditional hydrodesulfurization method in catalytically removing thiophenic sulfur compounds. In this work, four thiazolium-based ILs, that is, 3-butyl-4-methylthiazolium dicyanamide ([BMTH][DCA]), 3-butyl-4-methylthiazolium thiocyanate ([BMTH][SCN]), 3-butyl-4-methylthiazolium hexafluorophosphate ([BMTH][PF₆]), and 3-butyl-4-methylthiazolium tetrafluoroborate ([BMTH][BF₄]), are synthesized. The extractive capability of these ILs in removing thiophene (TS) and dibenzothiophene (DBT) from model fuel oils is investigated. [BMTH][DCA] and [BMTH][SCN] present better extractive desulfurization capability than [BMTH][BF₄] and [BMTH][PF₆], which may be ascribed to the additional π?π interaction between –C≡N (in [BMTH][DCA] and [BMTH][SCN]) and thiophenic ring (in TS and DBT); DBT in diesel fuel is more efficiently extracted than TS in gasoline. [BMTH][DCA] offers the best desulfurization results, where 64% and 45% sulfur removal are obtained for DBT and TS, respectively, at IL:oil mass ratio of 1:1, 25°C, 20 min. [BMTH][DCA] is thus selected to systematically investigate the effects of temperature, IL:oil mass ratio, initial sulfur content, multiple-extraction, and IL regeneration on desulfurization. The mutual solubility of [BMTH][DCA] with fuel oil is also determined. It is observed that the desulfurization capability is not too sensitive to temperature and initial sulfur content, which is desired in industrial application; the sulfur contents in gasoline and diesel fuel are reduced from 558 ppm to 20 ppm (after 5 cycles) and from 547 ppm to 8 ppm (after 4 cycles), respectively. This work may show a new option for deep desulfurization of fuel oils.     

Desulfurization of Diesel Fuel by Extraction with Lewis-Acidic Ionic Liquid

Abstract

Ionic liquids were found to be highly selective for the extractive removal of aromatic sulfur compounds from fuels at room temperature. The efficiency of ionic liquids for the removal of aromatic sulfur compounds is dependent on the properties and structure of the ionic liquids. In this work, the Lewis-acidic ionic liquid 1-butyl-3-methylimidazolium tetrahalogenoferrate(III) ([BMIM] [FeCl₄]) was synthesized and demonstrated to be more effective for the removal of aromatic sulfur compounds from diesel over ionic liquids 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM][PF₆]) and 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM] [BF₄]) because of its Lewis-acidic property. The ionic liquids favorably extracted organic compounds with a higher density of aromatic π-electrons. [BMIM][FeCl₄] ionic liquid can be regenerated through reextraction by hexane, and could be used in multiple steps for the removal of sulfur compounds from diesel.     

Comparison in the extraction behavior of uranium(VI) from nitric acid medium using CHON based extractants,monoamide, malonamide,and diglycolamide,dissolved in piperidinium ionic liquid

Liquid-liquid extraction of U(VI) from nitric acid medium was carried out using three different class of CHON based molecular extractants namely monoamide, malonamide, and diglycolamide present in 1-butyl-1-methylpiperidinium bis(trifluoromethanesulfonyl)imide ([C₄mpip][NTf₂]) ionic liquid. The extractants investigated were di-n-hexyloctanamide (DHOA), N,N-dimethyl-N,N-di-octyl-2-(2-hexyloxylethyl)malonamide (DMDOHEMA) and N,N,N’,N’-tetra(ethylhexyl)diglycolamides (T2EHDGA). The extraction behavior of uranium(VI) in ionic liquid medium was investigated as a function of various parameters, such as the duration and temperature of equilibration, aqueous phase concentrations of feed acid, extractant, NaNO₃, and ionic liquid cation, etc. The extraction of U(VI) observed in these systems were compared with each other and the distribution ratios of U(VI) decreased in the order T2EHDGA > DMDOHEMA > DHOA. The slope analysis of the extraction data was carried out to understand the mechanistic aspects of extraction. The extraction of U(VI) observed in [C₄mpip][NTf₂] ionic liquid was also compared with pyrrolidinium ([C₄mpyr][NTf₂]) and imidazolium ([C₄mim][NTf₂]) based ionic liquids under identical experimental condition.     

Novel ionic liquids as reaction medium for ATRP of acrylonitrile in the absence of any ligand

Atom transfer radical polymerization (ATRP) of acrylonitrile (AN) with ethyl 2-bromoisobutyrate (EBiB) as the initiator was firstly approached in the absence of any ligand in three novel ionic liquids, 1-methylimidazolium acetate ([mim][AT]), 1-methylimidazolium valerate ([mim][VT]) and 1-methylimidazolium caproate ([mim][CT]), respectively. All the polymerizations in the ionic liquids proceeded in a well-controlled manner. The polymerization in [mim][AT] not only showed the best control of molecular weight and its distribution but also provided a rather rapid reaction rate with the molar ratio of [AN]:[FeBr₂]:[EBiB] at 200:2:1. The resulting polyacrylonitrile was successfully used as the macroinitiator to proceed the chain extension polymerization in [mim][AT]. After simple purification, all the ionic liquids and FeBr₂ could be recycled and reused and had no effect on the living nature of polymerization.     

Deep Desulfurization of Gasoline Fuel using FeCl3-Containing Lewis-Acidic Ionic Liquids

The FeCl₃-containing Lewis-acidic ionic liquids (ILs) [C₆mim]Cl/FeCl₃(1:1.5), [C₆mim]Cl/FeCl₃(1:2), [C₈mim]Cl/FeCl₃(1:1.5), and [C₈mim]Cl/FeCl₃(1:2) were used as extractants for desulfurization of model fuel and gasoline fuel, respectively. The results demonstrate that these ILs are effective for the removal of sulfur compounds from model fuel under different mass ratio of IL to model fuel (1:1, 1:3, 1:5, 1:10) at 25°C. The extractive performance of ILs increased as the molar ratio of FeCl₃ to [C_nmim]Cl(n = 6, 8) varied from 1:1 to 1:2. The selectivity of sulfur compounds by extraction process followed the order of dibenzothiophene (DBT)>benzothiophene (BT) > 4,6-dimethyldibenzothiophene (4,6-DMDBT). The sulfur removal of gasoline fuel containing sulfur content of 440.3 ppmw could be up to 85.8%; that is to say that the sulfur content of gasoline fuel varied from 440.3 ppmw to 62.4 ppmw after one extraction stage. Moreover, the [C₆mim]Cl/FeCl₃(1:2) can be recycled for at least 4 times with a little decrease in the desulfurization activity.     

Trihexyl(tetradecyl)phosphonium hexafluorophosphate as an promising Extractant for extractive desulfurization from liquid fuels

Experimental data on extractive desulfurization (EDS) of dibenzothiophene (DBT), thiophene, benzothiophene, and other substituted derivatives of sulfur from liquid fuel using trihexyl(tetradecyl)phosphonium hexafluorophosphate ([THTDP][PF₆]) have been presented. The Fourier transform infrared spectrophotometer, ¹H-NMR, ¹³C-NMR, and ³¹P-NMR analysis have been discussed for molecular confirmation, and conductivity, solubility, and viscosity analyses of ([THTDP][PF₆]) were investigated. The effects of time, temperature, S-compounds, ultrasonication, and recycling of ([THTDP][PF₆]) on DBT removal from fuel were examined. Also, desulfurization of real fuels and multistage extraction was also tested. The data and results provided the significant insights of phosphonium ionic liquids as a promising solvent for EDS.     

Extraction of dioxouranium(VI) in small channels using ionic liquids

The extraction behaviour of dioxouranium(VI) from nitric acid solutions with tributylphosphate (TBP) dissolved (30%, v/v) in room temperature ionic liquids (viz. 1-butyl-3-methylimidazolium bis{(trifluoromethyl)sulfonyl}amide, [C₄mim][NTf₂], 1-decyl-3-methylimidazolium bis{(trifluoromethyl)sulfonyl}amide, [C₁₀mim][NTf₂], and trihexyltetradecylphosphonium bis{(trifluoromethyl)sulfonyl}amide, [P_6 6 6 14][NTf₂]) was investigated. The experiments were performed in a capillary (0.5 mm internal diameter) made of Teflon, operated in the plug flow regime. The effects of ionic liquid type, initial nitric acid concentration, and residence time on dioxouranium(VI) extraction were studied. UV–vis spectroscopy was used for the determination of the dioxouranium(VI) concentration in the ionic liquid phase. For increasing [HNO₃]_aq,init, the %extraction decreased and then increased for [C₄mim][NTf₂], while for the other two ionic liquids it increased. The %extraction also increased with residence time in the channel. Overall mass transfer coefficients were about 0.2 s^–1 in all TBP/ionic liquid systems at the initial nitric acid concentration of 3 M when a 10 cm capillary was used.     

Extraction of dibenzothiophene from dodecane using ionic liquids

The effect of ionic liquid loading, extraction temperature, and extraction time in the removal of dibenzothiophene from dodecane were investigated. Eighteen (18) ionic liquids were screened for its dibenzothiophene extraction ability. Imidazolium based ionic liquids with thiocyanate, dicyanamide and octylsulfate anions exhibited the highest extraction capabilities with 66.1%, 66.1%, and 63.6% of extraction efficiency respectively. Tributylmethylammonium methylcarbonate ionic liquid gave 61.9% extraction efficiency, which showed that π-π interaction between aromatic rings of sulfur compound and ionic liquid (IL) was not be the main extraction mechanism. A trend between specific volume and desulfurization efficiency of ILs was put forward, enabling researchers to predict ILs' desulfurization efficiency from its specific volume. It was also found that [C₄mim][SCN] can be reused in extraction without regeneration with considerable extraction efficiency of 41.9%. Huge saving on energy can be achieved if we make use of this IL behavior in process design, instead of regenerating IL after every time of extraction.     

Extraction Behavior of Cu(II) Ion From Chloride Medium to the Hydrophobic Ionic Liquids Using 1,10-Phenanthroline

The study of liquid-liquid extraction of Cu(II) ion was carried out by using a series of hydrophobic ionic liquids; 1-butyl-3-methylimidazolium hexafluorophosphate ([C₄mimPF₆]), 1-hexyl-3-methylimidazolium hexafluorophospahate ([C₆mimPF₆]), 1-butyl-3-methylimidazolium bistrifluoromethylsulfonyl imide ([C₄mimNTf₂]) and 1-hexyl-3-methylimidazolium bistrifluoromethylsulfonyl imide ([C₆mimNTf₂]) as extraction phase. Cu(II) prefer to extract into [C₄mimPF₆] which is the less hydrophobic of ionic liquids. The extraction behavior of Cu(II) ion depends on the type of counterion and the extraction of Cu(II) ion in ionic liquid system proceeds via similar mechanism with a molecular organic solvent. From these results, it was proposed that the extraction of Cu complexes from chloride medium proceeds through ion pair mechanism.     

Aggregation Behavior of Imidazolium-Based Amino Acid Ionic Liquid Surfactants in Aqueous Solution: The Effect of Amino Acid Counterions

Three kinds of imidazolium-based amino acid ionic liquid surfactants (AAILS), 1-tetradecyl-3-methylimidazolium _L-aminopropionic acid salt ([C₁₄mim][Ala]), 1-tetradecyl-3-methylimidazolium _L-2-pyrrolidinecarboxylic acid salt ([C₁₄mim][Pro]), and 1-tetradecyl-3-methylimidazolium _L-aminohydrocinnamic acid salt ([C₁₄mim][Phe]), were synthesized by employing natural amino acids as counterions. Their adsorption and self-aggregation behaviors in aqueous solution were investigated systematically by means of surface tension and electrical conductivity measurements. Surface tension results indicate that surface properties and micellization behavior of AAILS are significantly affected by counterions. The micellization of [C₁₄mim][Pro] and [C₁₄mim][Phe] is entropy-driven at low temperatures but enthalpy-driven at high temperatures, whereas [C₁₄mim][Ala] is enthalpy-driven throughout the whole temperature range, owing to the variation in hydrophobicity and size of amino acid counterions. The surface activity of [C₁₄mim][Phe] is superior to that of conventional imidazolium-based ionic liquid surfactants with the same hydrocarbon chain length, 1-tetradecyl-3-methylimidazolium bromide (C₁₄mimBr), indicating that the aromatic counterion can promote the micellar formation process.     

Fabrication of silver nanoparticles via self-regulated reduction by 1-(2-hydroxyethyl)-3-methylimidazolium tetrafluoroborate

Silver nanoparticles exhibiting antimicrobial properties via self-regulated reduction were successfully prepared by using hydroxylated ionic liquids in an aqueous phase without additives. A new water-phase synthesis of silver nanoparticles using 1-(2-hydroxyethyl)-3-methylimidazolium tetrafluoroborate ([HEMIm][BF₄]) and 1-(2′-hydroxyethyl)-2-methyl-3-dodecylimidazolium chloride ([C₁₂HEMIm][Cl]) was described. 1-(2-hydroxyethyl)-3-methylimidazolium tetrafluoroborate serves as both a reductant and a stabilizer in this fabrication. Furthermore, we presented the antimicrobial properties of the resulting silver nanoparticles through the minimal inhibitory concentrations (MIC) test.     

Deep oxidative–extractive desulfurization of fuels using benzyl‐based ionic liquid

Four benzyl‐based ionic liquids (ILs) were synthetized and used for deep desulfurization of model oil and real diesel fuel. The removal efficiencies of benzothiophene (BT) and dibenzothiophene (DBT) with [Bzmim][NTf₂] and [Bzmim][SCN] as extractants are higher than that with [Bzmp][NTf₂] and [Bzmp][SCN] as extractants. The desulfurization capability follows the Nernst's Law. A reactive extraction mathematical model for desulfurization was established. An oxidative‐extractive two‐step deep desulfurization method was developed. DBT was first oxidized by H₂O₂ with CH₃COOH as catalyst and then the unoxidized DBT and uncrystallized dibenzothiophene sulfoxide (DBTO₂) in model oil were extracted by [Bzmim][NTf₂], and finally the removal efficiency was 98.4% after one‐stage extraction. Besides, the removal efficiency of 4,6‐DMDBT was 96.4% after oxidation and one‐stage extraction processes. Moreover, the oxidative‐extractive two‐step deep desulfurization method was also effective for desulfurization of diesel fuel. The removal efficiency of sulfur reached up to 96% after oxidation and three‐stage cross‐current extraction processes. © 2016 American Institute of Chemical Engineers AIChE J, 62: 4023–4034, 2016     

Critical properties and acentric factors of ionic liquids

Since most ionic liquids (ILs) decompose before reaching their critical state, the experimental measurement of their critical properties are not possible. In this study, the critical temperatures, critical pressures and acentric factors of ten commonly investigated ILs were determined by making an optimum fit of the calculated vapor-liquid equilibrium data of binary mixtures of CO₂+IL to the experimental values found in literature. For this purpose, the Peng-Robinson equation of state (PR EoS) and the differential evolution optimization method were used. The ILs considered were 1-ethyl-3-methylimidazolium hexafluorophosphate ([emim][PF₆]), 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl) imide ([emim][Tf₂N]), 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim][BF₄]), 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim][PF₆]), 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl) imide ([bmim][Tf₂N]), 1-hexyl-3-methylimidazolium tetrafluoroborate ([hmim][BF₄]), 1-hexyl-3-methylimidazolium hexafluorophosphate ([hmim][PF₆]), 1-hexyl-3-methylimidazolium bis(trifluoromethylsulfonyl) imide ([hmim][Tf₂N]), 1-octyl-3-methylimidazolium tetrafluoroborate ([omim][BF₄]) and 1-octyl-3-methylimidazolium hexafluorophosphate ([omim][PF₆]). To evaluate the ability of the determined parameters in predicting the phase behavior of systems other than the systems that were used for parameter optimization, both sets of parameters obtained in this work and that of Valderrama et al. were used to predict bubble-point pressures of CHF₃+[bmim][PF₆] (by using the PR EoS and the Soave-Redlich-Kwong equation of state. The bubble-point pressures of CO₂+IL systems optimized in this study by the PR EoS were also determined using the Soave-Redlich-Kwong equation of state (SRK EoS). In addition, liquid densities of pure ILs were predicted using a generalized correlation proposed by Valderrama and Abu-Shark. In all cases, the various predicted properties of these ten ILs, were in better agreement with the experimental data, using the critical properties and acentric factor obtained in this study, compared to the values suggested by Valderrama et al.     

乙腈+[C4mim][Cl]、乙腈+[C4mim][BF4]、乙腈+[C6mim][Cl]的气液平衡测定与关联（英文）

Vapor pressures were measured for acetonitrile+1-butyl-3-methylimidazolium chloride ([C4mim][Cl]),+1-butyl-3-methylimidazolium tetrafluoroborate ([C4mim][BF4]) and+1-hexyl-3-methylimidazolium chloride ([C6mim][Cl]) at temperatures of 313 to 353 K by a quasi-static method. The experimental data for the binary sys-tems were correlated by the non-random two liquid (NRTL) equation with an average absolute relative deviation (AARD) of within 1.84%. The results indicate that the three ionic liquids (ILs) can result in a negative deviation from the Raoult's law for the binary solutions containing acetonitrile, and the affinity between ILs and acetonitrile mole-cules fol ows the order [C4mim][BF4]+acetonitrile N [C4mim][Cl]+acetonitrile N [C6mim][Cl]+acetonitrile.     

High-pressure solubility of carbon dioxide in imidazolium-based ionic liquids with anions [PF6] and [BF4]

The solubility of carbon dioxide in three ionic liquids (ILs) under supercritical fluid condition was measured at pressures up to 32 MPa and at temperatures of 313.15, 323.15, and 333.15 K in a high-pressure view cell. The imidazolium-derivative ionic liquids 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim][PF₆]), 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim][BF₄]), and 1-octyl-3-methylimidazolium tetrafluoroborate ([omim][BF₄]) were employed in this research. The effects of pressure, temperature, nature of anion and cation as well as the water content on the solubility of CO₂ in the ILs were investigated experimentally. The solubility of CO₂ in the IL was higher for the ILs with longer cationic alkyl group and for the ILs with lower anion polarity. The lower the water content or the lower the temperature as well as the higher the pressure, the higher was the solubility of CO₂.     

Recovery of Furfural from Aqueous Solution by Ionic Liquid Based Liquid–Liquid Extraction

Abstract

Liquid–liquid extraction with imidazolium based ionic liquids ([C₄mim][PF₆], [C₆mim][PF₆], and [C₈mim][PF₆]) is proposed for the separation of furfural or 5-methylfurfural from aqueous solution. Factors affecting the extraction of furfural or 5-methylfurfural have been studied. It was shown that the extraction equilibria can be achieved within 30 min and the process was less affected by the factors such as volume ratio and feed concentration. The partition coefficients of furfural and 5-methylfurfural decreased with increasing temperature. [C₆mim][PF₆] was found to have the best extraction ability among the three ionic liquids studied. Presence of small amount of NaCl or Na₂SO₄ in the aqueous phase results in the considerable increase in the partition coefficients of furfural because of the competitive hydration of the salts with furfural. A thermodynamic study revealed that the extraction process was driven mainly by hydrophobic interactions. Further experimental results indicated that furfural can be separated selectively from aqueous furfural/acetic acid mixtures.     

Effect of Anions on the Extraction of Lanthanides (III) by N,N′‐Dimethyl‐N,N′‐Diphenyl‐3‐Oxapentanediamide

Abstract

The extraction of microquantities of La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, and Y by N,N′‐dimethyl‐N,N′‐diphenyl‐3‐oxapentanediamide (DMDPhOPDA) in 1,2‐dichloroethane from aqueous media containing ClO₄ ^?, PF₆ ^?, (CF₃SO₂)₂N^? anions or by DMDPhOPDA in 1,2‐dichloroethane in the presence of 1‐butyl‐3‐methylimidazolium bis[(trifluoremethyl)sulfonyl]imide ([C₄mim][Tf₂N]) and 1‐butyl‐3‐methylimidazolium hexafluorophosphate ([C₄mim][PF₆]) from HNO₃ solutions has been studied. The effect of HNO₃ concentration in the aqueous phase and that of the extractant concentration in the organic phase on the extraction of metal ions is considered. The stoichiometry of the extracted complexes has been determined. The addition of HPF₆ and (CF₃SO₂)₂NH or their salts to the aqueous HNO₃ or HCl solutions leads to an enchancement of lanthanides (III) extraction by DMDPhOPDA. A considerable synergistic effect was observed in the presence of ionic liquids (IL) in the organic phase containing DMDPhOPDA. This effect is connected with the hydrophobic nature of the IL anion. The distribution of ILs between the equilibrium organic and aqueous phases can govern the extractability of lanthanides (III) in DMDPhOPDA‐IL systems.