Dicyanamide-based Ionic Liquids Research Articles

Experimental study on hypergolic ignition and non-ignition for dicyanamide-based ionic liquids at low impact velocity conditions

Ionic liquids have a wide engineering application foresight due to their easy and safe storage and handling while are limited by the unclear mechanism of hypergolic ignition. In this study, three dicyanamide-based ionic liquids with different cations, 1-allyl-3-methyl imidazolium ([AMIm]), 1-ethyl-3-methylimidazolium ([EMIm]) and 1-butyl-3-methyl-imidazolium ([BMIm]), are prepared to react with white fuming nitric acid through drop tests. The diameter of ionic droplet is 2.2 ​mm, the impact velocities are controlled at 0.16/0.45/0.62/0.82/1.01 ​m ​s-1 by adjusting the dropping height, and the whole reacting process is recorded by three cameras to provide macroscopic, microscopic and infrared details. The promotion effect of impact velocity on hypergolic ignition probability is confirmed for all the ionic liquids, and the minimum impact velocity for successful hypergolic ignition of each ionic liquid was determined. The temperature evolution of hypergolic process shows a non-monotonic trend, and a four-stage process was performed to reveal the hypergolic mechanism. The experimental results indicate that short-chain alkyl and unsaturated substituents in cations are favored for hypergolic ignition, and the datasets are conducive for kinetic model construction.

From heart drug to propellant fuels: Designing nitroglycerin-ionic liquid composite as green high-energy hypergolic fluids

New-generation green bipropellants based on ionic liquids for aircraft have attracted the attention of researchers. However, the major defects of ionic liquid propellants are their low specific impulse and incomplete combustion, which limits their practical application. In this work, a series of novel hypergolic fluids were prepared by mixing oxygen-rich nitroglycerin (NG) with fuel-rich dicyanamide-based ionic liquids. The complete dissolution of NG in ionic liquids makes these hypergolic fluids became self-supplying oxygen composite fuels, which generate much less solid residual products than pure hypergolic ionic liquids (HILs). Moreover, the addition of NG inhibited the micro-explosion between fuel and white fuming nitric acid (WFNA), extended the contact time between fuel and oxidizer. And a proper amount of NG in the fuel could suppress the secondary combustion. These composite fuels have high density (>1 g cm−3), low viscosity (as low as 13.49 cP), wide liquid operating ranges and acceptable ignition delay time. Additionally, the specific impulses of the composite fuels were higher than pure HILs. For the first time, this work provides a simple and reliable method to control the ignition properties of HIL by adding oxygen-enriched additives.

Effects of alkyl side-chain length on binding with bovine serum albumin, cytotoxicity, and antibacterial properties of 1-alkyl-3-methylimidazolium dicyanamide ionic liquids

In this study, the behavior of 1-alkyl-3-methylimidazolium dicyanamide ionic liquids (ILs) with ethyl, butyl, hexyl, octyl, and decyl side-chains was evaluated to gain a deeper insight into the potential hazards posed by ILs to the environment and organisms. The effects of the alkyl side-chain length on the interactions between the ILs and bovine serum albumin (BSA), the cytotoxicity and antibacterial performance of the ILs was evaluated. The BSA binding ability of the ILs increased with increasing alkyl side-chain length, and the binding constants of the ILs increased from 1.80 L/mol for 1-ethyl-3-methylimidazolium dicyanamide to 196 L/mol for 1-decyl-3-methylimidazolium dicyanamide. IL binding with BSA was a spontaneous process initiated by hydrophobic forces. This was confirmed using circular dichroism spectra, dynamic light scattering measurements and molecular docking simulations. The results of the cytotoxicity and antimicrobial activity of ILs demonstrated that the increase in alkyl side-chain length increased IL toxicity. The effects of the alkyl side-chain length of 1-alkyl-3-methylimidazolium tetrafluoroborate ILs on the interactions between ILs and BSA and cytotoxicity of the ILs were also evaluated. Furthermore, we demonstrated that tetrafluoroborate-based ILs were more toxic than dicyanamide-based ILs. Herein, we thoroughly describe the effects of the alkyl side-chain length on the properties of ILs and provide background information for future studies on the properties of carbon dots fabricated using ILs as precursors.

Forcing Dicyanamide Coordination to f-Elements by Dissolution in Dicyanamide-Based Ionic Liquids.

A robust general route to lanthanide dicyanamide (DCA–) complexes has been developed where f-element salts are dissolved in DCA–-based ionic liquids (ILs) directly or formed in situ, forcing coordination of these normally weakly coordinating soft N-donor anions, even in an ambient, non-moisture-excluding environment. A series of lanthanide complexes [C2mim][Ln(DCA)4(H2O)4] (C2mim = 1-ethyl-3-methylimidazolium; Ln = La, Nd, Eu, Tb, Dy, and Yb) and [C2mim]3n[La(OH2)4(μ2-DCA)4]n[La(OH2)2(μ3-DCA)3(μ2-DCA)4]2n(Cl)4n were crystallized under a variety of conditions using this methodology and structurally characterized using single crystal X-ray diffraction. Although not all examples were isostructural, the dominant feature across the series was the presence of [Ln(DCA)4(H2O)4]− anionic nodes with all terminal DCA– ligands accepting hydrogen bonds from the coordinated water molecules forming a 3D metal organic framework. To determine if any structural clues might aid in the further development of the synthetic methodology, the metal-free IL [C1mim][DCA] (C1mim = 1,3-dimethylimidazolium), a room-temperature solid, crystalline analogue of the reaction IL, which is liquid at room temperature, was also prepared and structurally characterized. The ready isolation of these compounds allowed us to begin an investigation of the physical properties such as the luminescence at room and low temperatures for the Eu, Tb, and Dy representatives.

Synthesis, Characterization, and Antimicrobial Toxicity Study of Dicyanamide-Based Ionic Liquids and Their Application to Liquid–Liquid Extraction

Four different dicyanamide-based ionic liquids (ILs), [Cnmpy][DCA] (n = 4, 6, 8, and 10), were synthesized, characterized, and used to separate ethylbenzene from n-octane. Equilibrium data for the corresponding ternary systems were measured at 313.15 K under atmospheric pressure. A higher selectivity is observed for lower aromatic concentrations in the feed (20% max); this is a key factor in selecting a suitable IL. The distribution ratio and selectivity obtained in this work are comparable to those of commercial solvents. The nonrandom two-liquid model (NRTL) was successfully used to correlate the experimental tie-lines and to calculate the phase compositions of the ternary systems. Moreover, the antimicrobial activities of the ILs were evaluated by examining their 50% effective concentrations (EC50) using the standard microbroth dilution test against four human bacterial pathogens. 1-Butyl 3-methylpyridinium dicyanamide [C4mpy][DCA] was found as the most suitable IL among those investigated because of i...

Experimental and theoretical study on extraction and recovery of naphthenic acid using dicyanamide-based ionic liquids

Naphthenic acid is a toxic component that is present in the crude oil. It causes severe operational problems for oil refineries. However, naphthenic acid is a useful raw material for many industrial processes. Thus, it is advantageous to extract and recover the naphthenic acid from crude oil. Ionic liquid has been considered as an environmental friendly material that can be used to extract naphthenic acid from crude oil. However, the characteristics of the ionic liquids to achieve the best extraction efficiency is still not completely known. In this research, the performance of the ionic liquids consists of diazabicyclo undecene (DBU) based cations and dicyanamide (DCN) anion in the extraction of naphthenic acid from acidic model oil was studied. Computer simulation of a mixture of naphthenic acid, ionic liquid, and n-dodecane was also performed. The study showed that the DBU-DCN based ionic liquids can effectively extract naphthenic acid from highly acidic model oil. The increase in the alkyl chain length on the cation increases the percent naphthenic acid extraction. Molecular simulation studies showed that the dicynamide anion interacting directly with the naphthenic acid. The alkyl chain on the DBU cation does not form any cage around the naphthenic acid as previously proposed. The study suggests that the biggest factor affecting naphthenic acid extraction efficiency is the extent of solubility of the polar ionic liquid in the non-polar oil.

Physicochemical characterizations of novel dicyanamide-based ionic liquids applied as electrolytes for supercapacitors.

Novel ionic liquids (ILs), containing a dicyanamide anion (DCA−), are synthesized and applied as suitable electrolytes for electrochemical double layer capacitors (EDLCs). The prepared ILs are either composed of triethyl-propargylammonium (N222pr+) or triethyl-butylammonium (N2224+) cations paired with the DCA− anion. The structure of the cation influences its electrostatic interaction with the DCA− anion and highly impacts the physical and electrochemical properties of the as-prepared ILs. The geometry and the length of the alkyl chain of the propargyl group in N222pr+ enhance the ionic conductivity of N222pr–DCA (11.68 mS cm−1) when compared to N2224–DCA (5.26 mS cm−1) at 298 K. It is demonstrated that the Vogel–Tammann–Fulcher model governs the variations of the transport properties investigated over the temperature range of 298–353 K. A maximum potential window of 3.29 V is obtained when N222pr–DCA is used as electrolyte in a graphene based symmetric EDLC system. Cyclic voltammetry and galvanostatic measurements confirm that both electrolytes exhibit an ideal capacitive behavior. The highest specific energy of 55 W h kg−1 is exhibited in the presence of N2224–DCA at a current density of 2.5 A g−1.

Separation of water/butan-1-ol based on activity coefficients at infinite dilution in 1,3-didecyl-2-methylimidazolium dicyanamide ionic liquid

The activity coefficients (γ13∞) at infinite dilution for 65 solutes and the effect of interaction between organic solvents or water on the interfacial and bulk properties of 1,3-didecyl-2-methylimidazolium dicyanamide, [D2MIM][DCA] were detected by the gas-liquid chromatography at six temperatures in range of (358.15–408.15) K. The data are provided for polar and non-polar solutes as alkanes, alkenes and alkynes, aromatic hydrocarbons, alcohols, ethers, ketones, acetonitrile, pyridine, 1-nitropropane, thiophene, esters as well as for water. The synthesis and the thermal properties of [D2MIM][DCA] are presented. The fundamental thermodynamic functions, the partial molar excess Gibbs energy, enthalpy and entropy at infinite dilution were calculated and discussed. The values of selectivity and capacity for the separation problem water/butan-1-ol were calculated from γ13∞ and compared to literature values for imidazolium-based, or dicyanamide-based ionic liquids (ILs) for the same separation problem. The data presented here shows that [D2MIM][DCA] reveals attractive selectivity and capacity in the comparison to measured earlier ILs in the chosen separation problem. These findings seem useful for future applications of this IL in projects of new technologies for water/butan-1-ol separation process.

Liquid-liquid separation of hexane/hex-1-ene and cyclohexane/cyclohexene by dicyanamide-based ionic liquids

The work presented focused on the experimental liquid-liquid phase equilibrium measurements in ternary systems {ionic liquid (1)+hex-1-ene (2)+hexane (3)} and (ionic liquid (1)+cyclohexene (2)+cyclohexane (3)} at temperature T=298.15K and ambient pressure. The dicyanamide-based ionic liquids (ILs) were discussed as solvents for two types of separation problems of hexane/hex-1-ene and cyclohexane/cyclohexene. The objective of this work was to explore the feasibility of six ILs, namely N-ethyl-N-methylmorpholinium dicyanamide, [EMMor][DCA], (3-hydroxypropyl)-1-methylmorpholinium dicyanamide, [N-C3OHMMor][DCA], 1-(3-hydroxypropyl)-3-methylimidazolium dicyanamide, [N-C3OHMIM][DCA], 1-(3-hydroxypropyl)pyridinium dicyanamide, [N-C3OHPy][DCA], (3-cyanopropyl)pyridinium dicyanamide, [N-C3CNPy][DCA] and (3-cyanopropyl)methylpyrrolidinium dicyanamide,[N-C3CNMPyr][DCA]. The separating ability of the investigated ILs was compared with the previously measured by us in ternary LLE ILs for these chosen separation problems. The effect of cation for the same anion was examined with respect to the selectivity and solute distribution ratio in these processes. The separation effectiveness of the [N-C3CNMPyr][DCA] in comparison with other ILs used in this work is the best for hexane/hex-1-ene separations but lower than those presented by us earlier for [EMIM][DCA], however with better solute distribution coefficient. The experimental tie-lines were correlated with the non-random two liquid NRTL model. The proposed [N-C3CNMPyr][DCA] may be used as an alternative solvent for the separation of alkenes from alkanes and [EMMor][DCA] for cyclohexane/cyclohexene separation.

Role of Cation Structures for Energetic Performance of Hypergolic Ionic Liquids

In recent years, novel hypergolic ionic liquids (HILs) have attracted much attention in energy and fuel fields due to their prominent advantages, including low volatility, high thermal stability, excellent energetic performances, and outstanding designability. To investigate the influence of cation structure on the properties and performances of HILs, nine different imidazolium dicyanamide-based ionic liquids were prepared, characterized, and evaluated as potential hypergolic fuels. The heat of formation and the net proton transfer (NPT) energies were calculated by an optimized theoretical model. Ignition delay (ID) time was obtained by a droplet test with a high-speed camera. The results suggest that all ionic liquids possess high density (>1 g/mL) and high thermal stability. 1-Ethyl-3-methyl imidazolium dicyanamide has the lowest viscosity of 15.2 cP, and 1-allyl-3-methyl imidazolium dicyanamide has the shortest ID time of 25 ms. The viscosities, densities, and energy properties depend on the structure ...

Bis(trifluoromethylsulfonyl)imide, or dicyanamide-based ionic liquids in the liquid–liquid extraction of hex-1-ene from hexane and cyclohexene from cyclohexane

In this work we studied the applicability of four imidazolium-based ionic liquids (ILs) with different allyl-, or benzyl-substituents and bis(trifluoromethylsulfonyl)imide, or dicyanamide anions in the separation of hex-1-ene/hexane and cyclohexene/cyclohexane compounds. Experimental values for liquid–liquid equilibrium (LLE) were obtained for various binary and ternary mixtures of {IL (1)+hex-1-ene (2)+hexane (3)} or {IL (1)+cyclohexene (2)+cyclohexane (3)} at T=298.15K and p=0.1MPa. The ILs studied were as follows: 1-allyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, [AMIM][NTf2], 1-allyl-3-methylimidazolium dicyanamide, [AMIM][DCA], 1-benzyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, [BzMIM][NTf2], 1-benzyl-3-methylimidazolium dicyanamide, [BzMIM][DCA]. These ILs were chosen after the analysis of the selectivities calculated from the limiting activity coefficients data. The results are useful for the design an industrial process of extraction. The dicyanamide-based ILs showed excellent results in terms of selectivity, but bis(trifluoromethylsulfonyl)imide-based ILs revealed twice better solute distribution ratio. The chromatography analysis revealed that the ILs used as an entrainers were not present in the hydrocarbon-rich layer, which is convenient for production process, because eliminates the step needed for the separation of the solvent. The [AMIM][DCA] showed suitable extractive properties to replace nowadays methods of separation for hex-1-ene/hexane and cyclohexene/cyclohexane compounds. All experimental data were correlated with the NRTL model. The experimental tie-lines were calculated in good agreement with each other.

Separation Based on Limiting Activity Coefficients of Various Solutes in 1-Allyl-3-methylimidazolium Dicyanamide Ionic Liquid

In the present work the limiting activity coefficients (γ13∞) for 65 solutes, including polar and nonpolar solutes as alkanes, alkenes, and alkynes as well as aromatic hydrocarbons, alcohols, water, ethers, ketones, acetonitrile, pyridine, 1-nitropropane, thiophene, and esters in the 1-allyl-3-methylimidazolium dicyanamide ([AMIM][DCA]) were determined by gas–liquid chromatography at six temperatures in the range of (308.15 to 358.15) K. The gas–liquid partition coefficients, KL at infinite dilution, and the fundamental thermodynamic functions, the limiting partial molar excess Gibbs energy, enthalpy, and entropy, were calculated. The values of selectivity and capacity for three separation problems as hexane/hex-1-ene, cyclohexane/cyclohexene, and ethylbenzene/styrene were calculated from γ13∞ and compared to literature values for imidazolium-based or dicyanamide-based ionic liquids (ILs) for the same separation problems. The data presented here shows that [AMIM][DCA] reveals one of the highest selectivit...

Dicyanamide-based ionic liquids in the liquid–liquid extraction of aromatics from alkanes: Experimental evaluation and computational predictions

In this work, we have studied the potential use of the 1-allyl-3-methylimidazolium dicyanamide ([amim][DCA]) and the 1-benzyl-3-methylimidazolium dicyanamide ([bzmim][DCA]) ionic liquids (ILs) in the liquid–liquid extraction of aromatic hydrocarbons. To design an industrial process of extraction of aromatic hydrocarbons from alkanes, it is essential to measure the liquid–liquid and vapor–liquid equilibria between solutes and solvent, and to perform also a thermophysical characterization of the solvent. Because of this, we have studied the liquid–liquid extraction of toluene from n-heptane at 313.2K and the vapor–liquid separation of n-heptane from toluene in the presence of [amim][DCA] and [bzmim][DCA] at 323.2K, 343.2K, and 363.2K. Densities and viscosities as a function of temperature and the thermal stability of both ILs were also determined. The [amim][DCA] showed suitable extractive and physical properties to replace sulfolane and an adequate maximum operation temperature (MOT) to be employed at industrial scale. The ([bzmim][DCA]) showed good extractive properties but high viscosities. To complete the study, the Conductor-like Screening Model for Real Solvents (COSMO-RS) methodology was employed to predict the liquid–liquid and vapor–liquid equilibria between the hydrocarbons and ILs and the physical properties of ILs. A comparative evaluation between experimental results and COSMO-RS calculated values was performed.

Synthesis and hypergolic activity evaluation of some new ammonium-imidazolium based ionic liquids

In this study, a new class of dicyanamide-based ionic liquids containing mono and dicationic counterparts was synthesized and characterized.

Synthesis and thermal characterization of new ammonium–imidazolium dual dicyanamide-based ionic liquids

Novel dual dicyanamide-based ionic liquids consisting of coupled ammonium–imidazolium cationic structures were synthesized and their thermal properties were studied. The molecular structures of these compounds were identified by NMR, FT-IR and CHN analysis. Viscosity measurements showed that the new ionic liquid with vinylimidazolium group has lower viscosity than the ionic liquid with methylimidazolium group. However, the densities of the new synthesized compounds are almost same.Thermal behaviors and heat capacities of these ionic liquids were also investigated by thermogravimetry (TGA) and differential scanning calorimetry (DSC). The results suggest that the new ionic liquids have thermal stabilities up to 200°C, as well as reasonable heat capacities in the range 25 to 100°C.

Solubility of CO2 in aqueous mixtures of monoethanolamine and dicyanamide-based ionic liquids

Two low viscous ionic liquids (ILs), 1-(2-hydroxyethyl)-3-methyl-imidazolium dicyanamide ([C2OHmim][DCA]) and 1-butyl-3-methylimidazolium ([Bmim][DCA]) were selected to mixed with aqueous 30wt% monoethanolamine (MEA) for CO2 absorption. The solubility of CO2 in the aqueous mixtures of MEA+ILs was measured over a range of CO2 partial pressure of 10–800kPa and ILs concentrations from 10 to 50wt% at 313.15K and 333.15K. Correlations of solubility as a function of CO2 partial pressure have been conducted with deviation of ±1.5%. Moreover, the density and viscosity of pure ILs and MEA+ILs+H2O systems with different IL mass fractions were measured at temperature varying from 293.15 to 333.15K.

Corrosion properties of metals in dicyanamide-based ionic liquids

Corrosion behavior of metals in 1-ethyl-3-methylimidazolium–dicyanamide, butylmethylpyrrolidinium–dicyanamide, and 1-ethyl-3-methylimidazolium chloride–chloroaluminate ionic liquids (ILs) is studied. The constituent anions, rather than the cations, are the predominant species that govern the IL corrosivity toward materials. Among the materials investigated, Ni shows the lowest corrosion current and the best resistance against anodic dissolution in the three ILs. In the dicyanamide-based ILs, 304 stainless steel, Ti, and Al also exhibit satisfactory anti-corrosion characteristics. However, the use of Cu, carbon steel, and Mg in the same environment should be avoided due to their poor corrosion resistance, especially under anodic polarization conditions.

Extractive denitrogenation of fuel oils with dicyanamide-based ionic liquids

The removal of nitrogen-compounds (N-compounds), e.g. basic and neutral species, from fuel oils is necessary because of their inhibiting effect on the hydrodesulfurization process. In this work, the extractive denitrogenation performance of four dicyanamide-based ionic liquids (ILs) with different cationic characteristics, i.e., aromatic 1-butyl-3-methylimdazolium dicyanamide ([BMI][N(CN)2]) and 1-ethyl-3-methylimdazolium dicyanamide ([EMI][N(CN)2]), cyclic ethylated tetrahydrothiophenium dicyanamide ([S2][N(CN)2]), and tetrahedral ethyldimethylsulfonium dicyanamide ([EtMe2S][N(CN)2]), is investigated using basic pyridine and neutral carbazole as representative N-compounds. These ILs are capable of effectively extracting the N-compounds from the fuel oils with carbazole being more efficiently extracted than pyridine; also, aromatic imidazolium ILs exhibit better performance than cyclic thiophenium and tetrahedral trialkylsulfonium ILs in the order [BMI][N(CN)2] > [EMI][N(CN)2] > [S2][N(CN)2] > [EtMe2S][N(CN)2]. Under ambient conditions, 1 : 1 (w/w) IL : oil, the N-content in the raffinate phase of the carbazole-containing fuel oil is undetected after <5 min of contact with [BMI][N(CN)2] and [EMI][N(CN)2], while 96.8% and 84.3% N-extraction efficiency is obtained after contact with [S2][N(CN)2] and EtMe2S][N(CN)2] respectively; for pyridine-containing fuel oil, the N-extraction efficiency in the aforementioned ILs is 72.7%, 69.1%, 63.5% and 59.8%, respectively. Compared with other ILs reported, the extractive performance of these ILs is competitive. [BMI][N(CN)2] is selected as a representative IL to undergo a series of parallel experiments to determine the influence of IL : oil mass ratio, temperature, initial N-content, and multiple extractions; a recyclability test is also performed. This work may present a new approach to fuel denitrogenation.

Electrooxidation of [(η5-C5H5)Fe(CO)2]2 As a Probe of the Nucleophilic Properties of Ionic Liquid Anions

The oxidative electrochemistry of [CpFe(CO)(2)](2), 1 (Cp = [eta(5)-C(5)H(5)](-)), was examined in detail in ionic liquids (ILs) composed of ions of widely varying Lewis acid-base properties. Cyclic voltammetric responses were strongly dependent on the nucleophilic properties of the IL anion, but all observations are consistent with the initial formation of 1(+) followed by attack from the IL anion. In [NTf(2)](-)-based ILs ([NTf(2)](-) = bis(trifluoromethylsulfonyl)amide), the process shows nearly ideal chemical reversibility as the reaction between 1(+) and [NTf(2)](-) is very slow. This is highly significant, as 1(+) is known to be highly susceptible to nucleophilic attack and its stability indicates a remarkable lack of coordinating ability of these ILs. In 1-methyl-3-butylimidazolium hexafluorophosphate, [bmim][PF(6)], the oxidation of 1 is still largely reversible, but there is more pronounced evidence of [PF(6)](-) coordination. In contrast, 1 exhibits an irreversible two-electron oxidation process in a dicyanamide-based IL. This overall oxidation process is thought to proceed via an ECE mechanism, details of which are presented. Rate constants were estimated by fitting the experimental data to digital simulations of the proposed mechanism. The use of [NTf(2)](-)-based ILs as a supporting electrolyte in CH(2)Cl(2) was examined by using this solvent/electrolyte as a medium in which to perform bulk electrolyses of 1 and 1*, the permethylated analogue [Cp*Fe(CO)(2)](2) (Cp* = [eta(5)-C(5)(CH(3))(5)](-)). These cleanly yielded the corresponding binuclear radical-cation species, 1(+) and 1*(+), which were subsequently characterized by electron paramagnetic resonance (EPR) spectroscopy. In addition to the above oxidation studies, the reduction of 1 was studied in each of the ILs; differences in cathodic peak potentials are attributed, in part, to ion-pairing effects. This study illustrates the wide range of electrochemical environments available with ILs and demonstrates their utility for the investigation of the redox properties of metal carbonyls and other organometallic compounds.

Extractive desulfurization of fuel oils with low-viscosity dicyanamide-based ionic liquids

Four low-viscosity ionic liquids (ILs) based on the dicyanamide anion ([N(CN)2]−), i.e., 1-butyl-3-methylimdazolium ([BMI][N(CN)2]), 1-ethyl-3-methylimdazolium ([EMI][N(CN)2]), ethylated tetrahydrothiophenium ([S2][N(CN)2]) and ethyldimethylsulfonium ([EtMe2S][N(CN)2]), have been investigated to determine their extraction capability for thiophene (TS) and dibenzothiophene (DBT) from model fuel oils. Aromatic imidazolium is more efficient than cyclic thiophenium and tetrahedral trialkylsulfonium; specifically, the S-extraction ability follows the order [BMI][N(CN)2] > [EMI][N(CN)2] > [S2][N(CN)2] > [EtMe2S][N(CN)2], with DBT being more efficiently extracted than TS. The S-extraction of [BMI][N(CN)2] has been investigated as a representative with respect to the influence of extraction temperature, IL:oil mass ratio, initial S-content, multiple extractions and reusability, along with its mutual solubility in oil. The percentage of S-removal from gasoline and diesel fuel were 48.5 and 68.7%, respectively, in a single extraction at 25 °C, 1:1(w/w) IL:oil, 5 min; the S-content in gasoline decreased from 599 ppm to 4 ppm after 5 extraction cycles and in diesel fuel decreased from 606 ppm to an undetectable value after 4 cycles. The mutual solubility is not pronounced and the extraction efficiency is not conspicuously changed after 6 regeneration cycles. It is worth noting that a short extraction time of < 5 min is observed for all the ILs at room temperature, which is understood by their low viscosities and effective mass transfer. This work may offer a new option for the deep desulfurization of fuel oils.