Extractive Desulfurization Process Research Articles

Preparation of the MoO3- Fe3O4 nanocomposites for deep oxidative desulfurization of model fuel: Optimization and experimental design

In the present study, the catalytic activity of the MoO3-Fe3O4 of molybdenum oxides prepared by the impregnation method was investigated in the extractive oxidative desulfurization (EODS) process. Structural characterization of the nanocomposite catalysts was studied by XRD, N2 adsorption–desorption isotherm, FT-IR, and VSM analyses. The EODS technology was applied to remove sulfur from a model fuel (dibenzothiophene in n-octane, DBT) using H2O2 as the oxidant, acetonitrile as the extracting solvent, and MoO3-Fe3O4 as the catalysts. Among the catalysts with various loadings of MoO3 on Fe3O4 nanoparticles (3, 6, 9, 12, and 15 wt%), the catalyst with 9 wt% MoO3 demonstrated the highest performance. Subsequently, the optimal design of the experiments using response surface methodology (RSM) based on Box-Behnken design (BBD) was applied to study the effects of the independent parameters such as O/S molar ratio, reaction temperature, and catalyst dosage on sulfur removal efficiency. Optimization studies were performed, and maximum sulfur removal efficiency of 98 % was achieved under the optimal conditions of 58 °C, O/S molar ratio: 5.9, and 0.116 g of 9 wt% MoO3-Fe3O4 as catalysts. The activity of the catalyst remained unchanged after six times recycling in the EODS process. Additionally, a catalytic reaction mechanism was proposed.

Oil extraction desulfurization based on ionic liquid: Back-extractant screening, experiment and process simulation

A comprehensive back-extractant screening method was first developed for regenerating ionic liquids (ILs) after oil extraction desulfurization (EDS). Statistical analysis was performed using the Technique for Order Preference by Similarity to an Ideal Solution (TOPSIS) with the Entropy Weighting Method (EWM) on screening indices obtained based on the COnductor-like Screening MOdel for Realistic Solvents (COSMO-RS) and the Quantitative Structure Activity Relationship (QSAR) models. CCl4 was selected as the optimal back-extractant among 196 candidates for regenerating the IL, 1-butyl-3-methylpyridinium dicyanamide ([BMPy][DCA]), targeting the simultaneous removal of thiophene (TS), benzothiophene (BT), dibenzothiophene (DBT), and 4,6-dimethyldibenzothiophene (4,6-DMDBT). The experimentally measured hexary liquid–liquid equilibrium (LLE) confirmed the satisfactory selectivities and distribution coefficients of CCl4. Based on the NRTL parameters correlated from the LLE data, a complete EDS process including IL-extraction and IL-regeneration was established and evaluated economically based on the total annual cost (TAC). The results demonstrated that this process significantly decreased the sulfur content from 500 ppm to less than 10 ppm. The study results verified the feasibility and effectiveness of the proposed method and showed the excellent industrial performance of the selected IL and back-extractant.

Choline-based Deep Eutectic Solvent for Extractive Oxidative Desulfurization of Model Oil

One of the hardest processes encountered by petroleum refining is sulfur elimination from fuel oil. There are many traditional methods executed but they caused drawbacks such as poor selectivity of sulfur compounds and toxic raw materials. Extractive oxidative desulfurization (EODS) caught the interest of researchers due to high selectivity of sulfur compounds and great desulfurization. Currently, researchers are investigating the use of ionic liquids (ILs) as green extractant, unfortunately they are expensive. This research is proposing and comparing the use of cheap biodegradable solvents called deep eutectic solvents (DESs), as extractants in removing sulfur from fuel oil. The DESs are synthesized through a combination of choline chloride - orcinol and choline chloride - ethylene glycol, and their structure is confirmed through FTIR. Their thermal properties are characterized by DSC and TGA. Their desulfurization performance is evaluated by type of DESs, different ratios of DES and model oil, different ratios of oxidant and sulfone and various temperatures which these factors are found to influence the result. The optimum conditions are found to be at 1:1 for DES and model oil ratio, 4 for O/S ratio and temperature at 85 °C with the extraction efficiency of 99.98%. In conclusion, this DES has high potential to be the cheap green alternative to the conventional extractant for extractive oxidative desulfurization process.

Improvement of extractive desulfurization for Iraqi refinery atmospheric residual

Extractive desulfurization (EDS) process of petroleum fuels via effective solvents has been widely investigated in recent decades and has an excellent future as an alternative technique to HDS process. This study was focused on removal of sulfur compounds from heavy Iraqi atmospheric residual oil (IARO) via EDS process without affecting its other properties. Different hydrocarbon solvents (light naphtha, n-heptane and n-hexane), solvent to oil ratios (4/1, 8/1, and 12/1), extraction times (30, 60, and 120 min), and extraction temperatures (30 °C, 60 °C and 90 °C) were investigated on the precipitation of sulfur in Iraqi atmospheric oil residue. The results were showed that increasing of solvent to oil ratio, extraction times, and extraction temperatures enhanced the performance of EDS process. The experimental results proved that 96% of sulfur compounds were eliminated from heavy residual oil using effective n-hexane as solvent under moderate operating conditions as follow: extraction temperature of 90 °C, extraction time of 60 min, and solvent to oil ratio of 12/1. This study prove that extractive desulfurization via hexane-like solvents at the best experimental conditions can achieve satisfactory sulfur removal efficiency of heavy oil via safe, fast, economically and effective process.

Novel Gemini ionic liquid for oxidative desulfurization of gas oil

The N1,N1,N3,N3-tetramethyl –N1,N3-diphenylpropane-1,3-diaminium dichloride ionic liquid (ILc) is an environmentally friendly catalyst for oxidative–extractive desulfurization of gas oil (sulfur content = 2400 ppm) in the presence of H2O2 as an oxidizing agent. The precise structure of the prepared IL was confirmed using FT-IR spectroscopy, and1H-NMR. The reaction temperature, IL ratios, H2O2 dosage, and reaction time were studied to assess their effects on the desulfurization efficiency. The thermodynamic parameters of the oxidation reaction were determined. A desulfurization efficiency of 84.7% was obtained after the extractive desulfurization process using acetonitrile as an organic solvent at a solvent to feed ratio of 1:1 (v/v). Furthermore, the prepared IL may be reused for at least six cycles without any significant change in its desulfurization performance or chemical structure, which confirms its high reusability.

Screening method and mechanism of ionic liquid as extractant in fuel extraction desulfurization process

AbstractBackgroundIn the production of ultra‐low sulfur fuels, the use of extraction processes to remove sulfides from the fuel has various advantages. The selection of a suitable extractant is key to the extraction process. Ionic liquids (ILs) are known as green solvents and are designable, but there is a wide variety. In this study, an IL screening method was developed based on a conductor‐like screening model‐segment activity coefficient (COSMO‐SAC) model and a fuzzy comprehensive evaluation model. In addition, the feasibility of the method was verified by fuel extraction desulfurization experiments. Finally, the separation mechanism was explored through intermolecular interactions.ResultsIn this study, suitable extractants were screened from 2400 ILs with 24 anions and 100 cation combinations. Based on the results of the fuzzy comprehensive evaluation model, five ILs were selected; 1‐hexyl‐3‐methylimidazolium hexafluorophosphate ([HMIM][PF6]) was selected as the extractant and the single desulfurization rate could reach 72.74%. After four desulphurization experiments, the sulfur content in the model oil decreased from 1200 to 6.98 μg/g. The interaction energy difference between [HMIM][PF6] + BT and [HMIM][PF6] + OC (ΔE = ‐12.8662 kJ·mol−1) is higher than those of the other four extractants.ConclusionThe feasibility of the screened method was verified by the extraction desulfurization experiment. [HMIM][PF6] was selected as the most suitable extractant. Furthermore, by analyzing the weak interaction between ILs and benzothiophene (BT) and n‐octane (OC), it was found that weak hydrogen bonds (HBs) and π–π interactions between [HMIM][PF6] and BT play important roles in the extraction process. © 2022 Society of Chemical Industry (SCI).

Extractive desulfurization of diesel fuel in a novel ultrasound-assisted spiral microfluidic contactor: Separation efficiency and energy consumption

A novel ultrasound-assisted spiral microchannel contactor was proposed to investigate the extractive desulfurization process of untreated diesel fuel with an initial sulfur content of 1690 ppmw. The experiments were divided into two sections based on the desulfurization contactors. The conventional batch experiments evaluated the mixing time (20, 40, 70, 100, and 130 min) and solvent to fuel volume ratio (0.25, 0.5, 0.75, 1, and 1.5) impacts on the desulfurization process efficiency. The continuous process was initiated by selecting a solvent, namely, methanol, acetonitrile, and dimethylformamide, in a microchannel contactor. It was shown that dimethylformamide has the best sulfur removal efficiency. The influence of volumetric flow rate (2.86, 3.5, 4.5, 6.3, 7.85, and 10.5 ml/min) on the separation efficiency and the process energy assessment at both silent and sonicated conditions were explored. It was found that the maximum value of desulfurization in the conventional batch process was about 41 % after 100 min, while the desulfurization efficiency of ultrasound-assisted microchannel contactor reached 70.3 % within 3.6 min. Depending on the fuel flow rate, it was shown that a 5–18 % increase in desulfurization rate could be obtained in sonicated mode. The energy consumption assessment illustrated that, at a 2.86 ml/min flow rate of diesel fuel (i.e., highest residence time), the addition of the sonication feature leads to an increase in sulfur removal from 59 % to 70.3 %. In contrast, the total sulfur removal per consumed electrical energy reduced from 902 mg/J to 0.0046 mg/J. It was concluded that, although with sonication mode, higher sulfur removal can be obtained, the electrical energy consumption in exchange for obtaining clean fuel energy drastically increased.

Molecular mechanism and extraction performance evaluation of diethylene glycol-based DES for extraction desulfurization process of fuel oil

From July 1, 2020, China has fully implemented the most stringent National VI emission standards for automobiles. Thiophenes (TPs) are main form of sulfur compounds in China crude oil. More than 80% of TPs is composed of dibenzothiophene (DBT). The upgrade of emission regulations will drive technological upgrades. Deep eutectic solvent (DESs) has great potential for industrial application because of its simple preparation, low cost and high extraction rate. Based on the quantum chemistry (QC), this work proposed a screening method for DESs to extract DBT from Heptane + DBT mixtures. Through quantum chemical (QC) calculation, the probability distribution of surface charge density σ (σ-profile) was obtained, and suitable DES was selected as the extractant. Molecular dynamics (MD) simulation of the microscopic behavior of the involved DESs and mixtures was carried out, and the diffusion and aggregation behavior of sulfides in DES were studied. Through the analysis of intermolecular interaction energy, radial distribution function, spatial distribution function and self-diffusion coefficient, the formation of DESs and the extraction mechanism of DBT as well as the influence of hydrogen bond acceptors (HBA)/ hydrogen bond donors (HBD) type and molar ratio were explained. The effects of process parameters and thiophene compounds on desulfurization were studied.

Extractive desulfurization using piperidinium based ionic liquids with Lewis acids

This work includes the preparation of ionic liquid 1,4-dimethylpiperidinium iodide [MMPip]I and its salts with ferric chloride as Lewis acid in different molar proportions [MMPip]I/nFeCl3 (n=1,2,3). The prepared compounds were diagnosed by spectroscopic and physical methods such as 1H-NMR, FT-IR, elemental analysis (CHN) and other techniques. The thermal stability of these compounds was studied to use in the extractive desulfurization process (EDS). The efficiency of these compounds in removing sulfur compounds from the petroleum model was examined using dibenzothiophene (DBT) with a concentration of 1000 ppm dissolved in the solvent of normal hexane. The results showed that the compounds used had an acceptable efficiency of up to 30% despite using medium amounts of the extracted agent relative to the oil model; these compounds have a promising future in extractive sulfur removal processes.

Extractive desulfurization of model oil using 1-methyl-4-ethyl pyridinium iodide ionic liquids with some Lewis acids

The ionic liquid (IL) (1-methyl-4-ethyl pyridine-1-ium iodide) [MEPy]I in this work was created through a direct reaction between 4-ethyl pyridine and methyl iodide. Subsequently, complex salts were prepared using Lewis acids (ferrous chloride and copper chloride) in molar ratios of 1:1 and 1:2, ionic liquid: metal chloride. Nuclear magnetic resonance spectroscopy 1H-NMR, elemental analysis (CHN), infrared spectra FT-IR, and other methods were used to identify the prepared compounds. Moreover, the study of the thermal stability of the prepared compounds. These compounds were tested in the extractive desulfurization process (EDS). Using a model oil sample containing dibenzothiophene (DBT) as an aromatic organosulfur compound dissolved in solvent (n-decan) at a concentration of 1500 ppm. The sulfur percentage was estimated before and after treatment by gas chromatography technique GC-FID, and the conditions were determined (time and concentration of the extracted substance), as it was found that ionic liquids of pyridine base and its complex salts with ferrous and copper chlorides have good efficiency in the process of removing sulfur (EDS).

Enhanced oxidative desulfurization of fuel in ionic liquid by TiO2 quantum dots catalysts modified with Anderson-type polyoxometalate

A novel quantum-scale catalyst named CoMoxOy-TiO2 obtained from TiO2 quantum dots (QDs) combined with Anderson polyoxometalates (NH4)3Co(OH)6Mo6O18 was synthesized by an effective sol-gel method and employed in extraction and catalytic oxidative desulfurization (ECODS) process. Ionic liquids (ILs) were selected as both extract solvents and reaction media in the ECODS system. The catalyst was characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy spectra (FT-IR), UV–vis diffuse reflection spectra (UV–vis), X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM) and Transmission electron microscope (TEM). The desulfurization system exhibits very high catalytic activity that 100% desulfurization was obtained with 50 mg catalyst in IL [Omim]BF4 at 30 °C. Besides, various of S-containing compounds including BT and 4,6-DMDBT were also investigated under the optimal conditions. This work actually not only supplies a novel and green process for deep desulfurization of diesel, but also provides an effective preparation method for quantum-scale catalyst which could be extended as a general approach to other systems for the preparation of highly dispersed nanosized structure catalyst.

Synthesis and Characterization of Some Transition Metals Complex Salts of Pyridinium Iodide Ionic Liquids: Application on Extractive Desulfurization

The ionic liquid of pyridine base [emPy]I was prepared. Then, a series of complex salts were designed from it with some transition metal chlorides Fe(III), Co(II), Ni(II) and Cu(II) as Lewis acids. The compounds were characterized by spectroscopic and physical methods such as nuclear magnetic resonance "1H-NMR", infrared spectroscopy "FT-IR", electronic spectrum "UV", mass spectroscopy "MS", elemental analysis "CHN", magnetic susceptibility, molar conductivity, and other methods. The thermal stability of these compounds was also verified within the temperature range of (25-1000 °C). [emPy]I and its complex salts were tested in the extractive desulfurization process EDS. The procedure treats them with the model fuel of sulfur content of 2000 ppm, prepared from dissolving dibenzothiophene DBT in n-hexane. The ratio of sulfur removal was estimated using the GC-FID technique. The optimal conditions for EDS process were studied, and the possibility of reusing the extractant more than once without regeneration.

Extraction desulphurization of fuels using ZIF-8-based porous liquid

Porous ionic liquids (PILs), coupling the permanent porosity of porous solids with the good solubility and liquid fluidity of ionic liquids, have been successfully synthesized and offer great opportunities in the development of adsorption and separation. In this study, series of zeolitic imidazolate framework-8 based PILs (ZIF-8-PILs) are constructed and used for extractive desulfurization of fuels. Effects of extraction time, temperature, mass ratio of PILs to model oil and initial sulfur concentration on desulfurization are investigated. ZIF-8-based N-butylpyridinium bis(trifluoromethanesulfonyl)imide PILs (ZIF-8/[Bpy][NTf2]) exhibits encouragingly high performance with the removal efficiencies of thiophene (TH) and benzothiophene (BT) of 72.41% and 80.87% under optimum extraction conditions. After extraction, PILs can be facilely recovered and reused with steady removal efficiencies. The stable liquid porous structure of ZIF-8-PILs plays a dominant role for the excellent extractive desulfurization performance, and the synergistic effects of electrostatic interaction, hydrogen bonding and π-complexation interaction among ILs, ZIF-8 and sulfur compounds are also closely relevant to the high removal efficiency. The results of this work show that PILs are a new and promising extractant for fuel extraction desulfurization process.

A Hierarchical Hybrid Method for Screening Ionic Liquid Solvents for Extractions Exemplified by the Extractive Desulfurization Process

A hierarchical hybrid method combining experimental-database-derived estimation of extraction performance, quantitative structure–property relationship (QSPR)-based assessment of IL physical and environmental properties, liquid–liquid extraction (LLE) measurement, and process evaluation is proposed to screen practically suitable ionic liquid (IL) solvents for different extractions. From the literature, 47 424 infinite dilution activity coefficient (IDAC) data including 12 IL families (e.g., imidazolium, pyridinium, ammonium, etc.) and 13 organic families (e.g., alkanes, aromatics, alcohols, etc.) are collected. On the basis of the IDAC data, the extraction performance of ILs for a specific separation can be estimated in terms of the distribution ratio and selectivity at infinite dilution. The ILs with potentially high extraction performance and meeting the physical and environmental properties criteria are selected to perform LLE experiments. Subsequently, process simulation and evaluation using the selected IL solvents are performed by Aspen Plus. To exemplify the proposed method, the extractive desulfurization (EDS) process is taken as a case study, where [EMIM][MESO₃] (1-ethyl-3-methylimidazolium methanesulfonate) and [EIM][NO₃] (1-ethylimidazolium nitrate) are selected after IDAC database searching and QSPR analysis. Experimental LLE with the two ILs are determined, demonstrating their promising extraction performance with the maximum selectivity (S₂₃ᵐᵃˣ) for thiophene/heptane of 420 and 281.9, respectively. By fitting the NRTL model correspondingly, two processes using the screened ILs and sulfolane are developed and compared using Aspen Plus. It turns out that the two ILs save 66% and 48% in solvent requirements and 54% and 55% in energy consumption compared to those of sulfolane for the EDS task, respectively.

Selection of ionic liquid for extraction processes: Special case study of extractive desulfurization

Selecting of appropriate ionic liquids (ILs) as extracting agents is a key to ensuring an extraction process. Therefore, this study illustrates a systematic method for an extractive desulfurization (EDS) process to select the most promising ILs. The proposed method combines: 1) COSMO-RS calculation of the mutual solubility of ILs and fuel oil, and the capacity of ILs for the S-compounds, 2) experimental investigation of the prescreened ILs for their desulfurization ability, 3) and Aspen Plus simulation of developing a new insight into the industrial application of EDS. Based on the obtained results, [C1pyr][H2PO4] and [C1pyr][HSO4] having small mutual solubility with fuel oil, high extraction capacity for S-compounds and high desulfurization efficiency are selected as two promising ILs. Considering the qualification of the low sulfur content standard and real industrial applications, [C1pyr][H2PO4] is recognized as the most favorable solvent for the EDS process. The proposed method initiating from micro-level to experimental stage and finally to industrial stage can preferably be extended over a variety of extraction application for selection of the promising ILs.

Improving the extraction of sulfur-containing compounds from fuel using surfactant material in a digital baffle reactor

Abstract Extraction desulfurization process (EDP) for dibenzothiophene (DBT) from model light gas oil (LGO) improved using solvent mixture with new surfactant material (sodium thiosulfate) in digital baffle batch reactor (DBBR). Surfactant material was help increase extraction surface through increase dispersion of solvent in LGO. Reactor design was the best designer where negligible region of died zone in the reactor, rotation of fuel beside of wall, because adding the baffle on the wall. The blade design was distributes hexagonal holes that help liquid cross with solvent and this increases mixing and mass transfer DBT from model LGO to solvent. Operational conditions effects on extractive desulfurization process (EDP) it’s found such as solvent mixture (methanol, ethanol and toluene) to LGO model ratio, speed of impeller, extraction temperature, extraction time and effect surfactant were explored. Optimal experimental results represented that the extraction conditions were; (methanol = 10 ml, ethanol = 10 ml, toluene = 10 ml and volume of cocktail solvent equal to 30 ml MET))/model of LGO ratio speed of impeller 450 rpm, extraction time 21 min and extraction temperature 85 °C. Maximum DBT removal from model LGO was obtained at 89.8%, at this operating condition. Higher polarity of DBT was obtained when solvent used 30 ml MET. For removal dibenzothiophene (DBT) from model light gas oil, the results indicate that the extraction desulfurization process is suitable method to improve fuel quality.

A study of the desulfurization selectivity of a reductive and extractive desulfurization process with sodium borohydride in polyethylene glycol

The selectivity of a facile reductive and extractive desulfurization process was studied. In this desulfurization method, polyethylene glycol was used as the extractant, and sodium borohydride was used as the reductant. Several different simulated fuels were prepared by dissolving thiophenic sulfides, methylbenzene and hexylene in octane. The results showed that methylbenzene and olefins had different effects on different sulfur compounds during this desulfurization process. The extraction and reduction mechanisms were also explained. Four factors could affect the desulfurization performance: (1) intermolecular hydrogen bonding: (a) active O bonding with aromatic H or (b) S bonding with H atoms in hydroxide radicals, (2) “like-dissolves-like” interactions between polyethylene glycol and thiophenic sulfides, (3) the methyl steric hindrance effect and the electron density of sulfur atoms, and (4) the combination of S atoms with produced nickel boride to form active desulfurization centres. The desulfurization reaction path was also deduced according to the GC/MS results.

Optimal extractive and reductive desulfurization process using sodium borohydride in situ generated via sodium metaborate electroreduction in ionic liquid

In order to lower desulfurization cost, the NaBH4 preparation via NaBO2 electroreduction was introduced into the integrated process of extraction and reductive desulfurization. Accordingly, a novel desulfurization method was developed where NaBH4 can be recycled at the same time as desulfurization. The process of NaBH4 preparation via NaBO2 electroreduction was analyzed by cyclic voltammetry and the effect of pulse parameters on desulfurization efficiency was optimized by orthogonal experiments. Under optimal conditions desulfurization efficiency of more than 97 % was obtained for model fuel oil. Desulfurization mechanism and kinetics was probed. Results showed that the desulfurization of DBT should proceed over direct cleavage of CS bond and desulfurization reaction could be treated as pseudo-first-order reaction. Furthermore, the structures of original and recycled ionic liquids (ILs) were analyzed by nuclear magnetic resonance and the desulfurization performance of the recycled ILs was also investigated. Results showed that ILs maintained their original structures after regeneration and displayed good reusability. In summary, the novel desulfurization process is feasible and promising.

Extractive desulfurization of fuels using trialkylamine-based protic ionic liquids

Despite the extraction desulfurization of fuel oils using ionic liquids (ILs) as promising alternatives to traditional extractants has attracted worldwide attention, the drawbacks of ILs, such as poor extraction efficiency, high cost and complex preparation, have limited their further application in industrial scale. In this study, a series of trialkylamine-based protic ionic liquids (PILs) were synthesized and characterized, and their extraction desulfurization for thiophene (TH), benzothiophene (BT), and dibenzothiophene (DBT) in model oil was carried out. Effects of PIL species, extraction time, temperature, PIL dosage, and initial sulfuric concentration on desulfurization efficiency were investigated. Experimental results showed that the PILs exhibited higher extraction ability for TH, BT, and DBT as compared to the reported ILs. Under optimal conditions, the removal efficiency of TH, BT, and DBT using tris(3,6-dioxaheptyl) ammonium salicylate ([TDA][SA]) as extractant was 72.68%, 76.31%, and 83.94%, respectively. Finally, the suggested PIL can be easily regenerated and reused via a back extraction process. After 5 extraction cycles, the removal efficiency has no noticeable decrease. With advantages such as higher desulfurization efficiencies, cheap and easily obtained raw materials and simple synthetic process, this study will provide new green solvents for extraction desulfurization process of fuels.

Acid Dicationic Ionic Liquids as Extractants for Extractive Desulfurization

A series of imidazole- and pyridine-based dicationic ionic liquids (DILs) were synthesized and employed in extractive desulfurization (EDS) for the removal of sulfur compounds from commercial fluid catalytic cracking (FCC) gasoline. The influence parameters in the EDS process and regeneration of DILs are discussed. Under optimum operating conditions, the desulfurization efficiency can reach 79.72%. After five cycles, the sulfur content was reduced to less than 10 μg/g, and deep desulfurization was realized. The regeneration of the used DILs was performed by back-extraction, and the Fourier transform infrared and 1H nuclear magnetic resonance (NMR) spectra proved that the structure of DILs did not change. The relationship between acid strength and the desulfurization effect of DILs was studied by UV–vis spectroscopy. According to 1H NMR characterization, the main mechanism of the DILs' EDS process may be the interaction of π–π bonds. It is inferred from the chemical shift that the DILs have larger cation volume, which was conducive to increasing the aromatic π-electron density, producing stronger π–π interaction between the cations and aromatic sulfides, and thus having better EDS effect than ILs with mono-cationic. Finally, the adaptability of DILs was studied, and DILs have excellent desulfurization adaptability for different FCC gasolines.