Functionalized ionic liquid and preparation method thereof

Abstract

The invention discloses a functionalized ionic liquid and a preparation method thereof, and belongs to the field of ionic liquids. The preparation method of the functionalized ionic liquid comprises the following steps: mixing alkyl imidazole, halogenated olefin, a polymerization inhibitor and a reaction solvent, carrying out heating reaction, and carrying out external evaporation, extraction and drying on a crude product to obtain the 1-alkenyl-3-alkyl imidazole halide ionic liquid, the anion of the 1-alkenyl-3-alkyl imidazole halide ionic liquid exchanges with other anions, so that the 1-alkenyl-3-alkyl imidazole ionic liquid is prepared. By improving the reaction process and post-treatment conditions, various functionalized ionic liquids are obtained with high yield and high purity.

Description

Technical Field

[0001] This invention belongs to the field of ionic liquid synthesis, specifically relating to a functionalized ionic liquid and its preparation method. Background Technology

[0002] Functionalized ionic liquids are those that incorporate specific functional groups to acquire specific functions, and their applications have expanded from catalysis to fields such as battery materials and protein separation. Due to their advantages such as low melting point, high polarity, low volatility, resistance to oxidation, and stability to water and air, ionic liquids are used as reaction solvents, extractants, and catalysts in organic synthesis. Their non-flammability and high conductivity make them advantageous alternatives to traditional electrolytes. Furthermore, copolymerization with template molecules and crosslinking agents to form molecularly imprinted polymers with targeted recognition sites can be used in membrane separation, solid-phase extraction, and chemical sensing.

[0003] Patent CN102796048 discloses a method for extracting cellulose using functionalized ionic liquids, dissolving cellulose with the obtained 1-allyl-3-methylimidazolium acetate, reducing the amount of solvent used, the dissolution time, and the dissolution temperature; Patent CN111718427B proposes to prepare high-aldehyde-content dialdehyde cellulose using a mixed solvent of organic solvent and functionalized ionic liquid, alleviating the problem of easy degradation of dialdehyde cellulose, with a product yield of over 95%; Patent CN119833706A proposes to prepare solid electrolytes using alkenyl ionic liquids as polymer monomers, significantly improving the specific capacity of the battery, further increasing the energy density of the battery, improving battery stability, and mitigating the impact of impedance during battery charging and discharging; Patent 116159544A uses functionalized ionic liquids as one of the raw materials to synthesize molecularly imprinted polymers, which can be used for targeted recognition and separation of hemoglobin in complex systems, and has potential applications for the separation of macromolecular natural products. Summary of the Invention

[0004] To address the aforementioned problems, this invention provides a functionalized ionic liquid and its preparation method, solving the limitations of monomer substrates, low product yield, and low purity in the preparation of functionalized ionic liquids in the prior art, and obtaining a variety of functionalized ionic liquids with high yield and high purity.

[0005] This invention is achieved through the following technical solution: This invention discloses a functionalized ionic liquid having the following general chemical structural formula: , Where n is 1, 2, 4, 6, 8, 10, or 12, m is 1 to 4, and X is anion with the following structure: Cl - ,Br - I - BF4 - PF6- HSO4 - HCO3 - H2PO4 - NO3 - CH3COO - CF3SO3 - (CF3SO2)3C - 、Ts - TFSI - or SCN - .

[0006] The present invention provides a method for preparing the functionalized ionic liquid according to claim 1, wherein the anion is Cl. - ,Br - or I - The preparation method is as follows: alkylimidazolium, haloalkene, polymerization inhibitor and reaction solvent are mixed in a certain proportion and reacted at 30~80℃ for 2~8h; the reaction solvent and most of the unreacted haloalkane are distilled off from the reaction liquid, the extraction solvent is added, mixed well, allowed to stand and separated, and a small amount of unreacted haloalkane is separated; the crude product after separation is dried to obtain 1-alkenyl-3-alkylimidazolium halide ionic liquid.

[0007] The present invention provides a method for preparing the functionalized ionic liquid according to claim 1, wherein the anion is BF4. - PF6 - HSO4 - HCO3 - H2PO4 - NO3 - CH3COO - CF3SO3 - (CF3SO2)3C - 、Ts - TFSI - or SCN - The preparation method is as follows: Sodium or potassium salt containing anions and 1-alkenyl-3-alkylimidazolium halide ionic liquid are added to a mixed solvent in a 1:1 molar ratio. The reaction is assisted by ultrasound and carried out for 1-3 hours. After standing and separating the layers, the halide salt is separated. The organic phase is washed with water and dried under vacuum to obtain a series of 1-alkenyl-3-alkylimidazolium ionic liquids.

[0008] According to the preparation method described above, the molar ratio of alkylimidazolium to haloolefin is 1:1.05~1.5.

[0009] According to the preparation method described above, the polymerization inhibitor is one of hydroquinone, p-hydroxyanisole, p-tert-butylcatechol, 2,6-di-tert-butyl-p-cresol, benzoquinone, and TEMPO, and the amount used is 0.5% to 1% of the mass of the haloolefin.

[0010] According to the preparation method described above, the solvent should be an organic halogenated solvent, such as one or more of dichloromethane, chloroform, carbon tetrachloride, dichloroethane, trifluoroethanol, hexafluoroisopropanol, trifluoroacetic acid, thionyl chloride, trifluorotoluene, and chlorobenzene, and the amount used should be 0.5 to 1.2 times the mass of the alkylimidazole.

[0011] According to the preparation method described above, the extraction solvent is one or more of the following: diethyl ether, petroleum ether, n-hexane, cyclohexane, methyl tert-butyl ether, tetrahydrofuran, dioxolane, and dioxane, and the amount used is 0.3 to 0.7 times the mass of the haloolefin.

[0012] According to the preparation method described above, the mixed solvent is water and dichloromethane, the amount of water is B, and the amount of dichloromethane is 0.3 to 0.5 times the mass of the 1-alkenyl-3-alkylimidazolium halide ionic liquid.

[0013] According to the preparation method described above, B = (0.8~1.0)a, where B is the actual mass of water used in the reaction, and a is the mass of water required to prepare a saturated halide salt aqueous solution at room temperature.

[0014] According to the preparation method described above, the ultrasonic heating temperature is 20~60℃.

[0015] The beneficial effects achieved by this invention are as follows: This invention uses carbon tetrachloride or hexafluoroisopropanol as the reaction solvent and diethyl ether or tetrahydrofuran as the extractant. Compared with traditional preparation methods, it achieves a high raw material conversion rate and produces a high-purity 1-alkenyl-3-alkylimidazolium halide ionic liquid product. The preparation method of the 1-alkenyl-3-alkylimidazolium ionic liquid provided by this invention reduces the reaction temperature and the amount of mixed solvent by adding ultrasonic-assisted equipment, and separates the inorganic salt byproducts in one step. The process is simple and conducive to industrial production. Detailed Implementation

[0016] The following examples further illustrate the above-described content of the present invention, but it should not be construed as limiting the scope of the subject matter of the present invention to the following examples. All technologies implemented based on the above-described content of the present invention fall within the scope of the present invention.

[0017] The functionalized ionic liquid of this invention has the following general chemical structural formula: , Where n is 1, 2, 4, 6, 8, 10, or 12, m is 1 to 4, and X is anion with the following structure: Cl - ,Br - I - BF4 - PF6 - HSO4 -HCO3 - H2PO4 - NO3 - CH3COO - CF3SO3 - (CF3SO2)3C - 、Ts - TFSI - or SCN - .

[0018] The preparation method of the present invention is as follows, comprising the following steps: When the anion is Cl - ,Br - or I - The preparation method of 1-alkenyl-3-alkylimidazolium halide ionic liquid is as follows: Alkylimidazolium, haloalkene, polymerization inhibitor, and reaction solvent are mixed in a certain proportion and reacted at 30-80℃ for 2-8 hours. The reaction solvent and most unreacted haloalkanes are distilled off from the reaction solution. An extraction solvent is added, mixed, allowed to stand, and separated to obtain a small amount of unreacted haloalkanes. After separation, the solution is dried to obtain 1-alkenyl-3-alkylimidazolium halide ionic liquid. The molar ratio of alkylimidazolium to haloalkene is 1:1.05-1.5. The polymerization inhibitor is 2,6-di-tert-butyl-p-cresol, and the amount used is 0.5%-1% of the mass of the haloalkene. The reaction solvent is dichloroethane, hexafluoroisopropanol, or chlorobenzene, and the amount used is 0.5-1.2 times the mass of the alkylimidazolium. The extraction solvent is diethyl ether, tetrahydrofuran, or dioxane, and the amount used is 0.3-0.7 times the mass of the haloalkene.

[0019] When the anion is BF4 - PF6 - HSO4 - HCO3 - H2PO4 - NO3 - CH3COO - CF3SO3 - (CF3SO2)3C - 、Ts - TFSI - or SCN -The preparation method of 1-alkenyl-3-alkylimidazolium ionic liquid is as follows: Sodium or potassium salts of the following anions and 1-alkenyl-3-alkylimidazolium halide ionic liquid are added to a mixed solvent in a 1:1 molar ratio. The reaction is assisted by ultrasound for 1-3 hours. After standing and separation, the halide salts are separated. The organic phase is washed with water and dried under vacuum to obtain a series of 1-alkenyl-3-alkylimidazolium ionic liquids. The mixed solvent is water and dichloromethane. The amount of water used is B, where B = (0.8-1.0)a, and a is the mass of water required to prepare a saturated halide salt aqueous solution at room temperature. The amount of dichloromethane used is 0.3-0.5 times the mass of the 1-alkenyl-3-alkylimidazolium halide ionic liquid. The ultrasonic heating temperature is 20-60℃.

[0020] The present invention will be further described below with reference to specific products and corresponding parameters: Example 1: Preparation of 1-allyl-3-methylimidazolium chloride 143.5 g of bromopropene, 0.7 g of 2,6-di-tert-butyl-p-cresol, and 62 g of hexafluoroisopropanol were added to a 500 mL reactor, along with 123.2 g of N-methylimidazolium. The mixture was stirred and heated to 30 °C for 3 h. After the reaction was completed, the hexafluoroisopropanol and the remaining bromopropene were removed by external evaporation. 43 g of diethyl ether was added, and the mixture was thoroughly mixed and allowed to stand for separation. The product layer was dried to obtain 158.2 g of 1-allyl-3-methylimidazolium chloride, which was found to have a purity of 99.98% and a yield of 99.78% by HPLC.

[0021] Example 2: Preparation of 1-enhexyl-3-methylimidazolium bromide 330.2 g of bromopropene, 2.6 g of 2,6-di-tert-butyl-p-cresol, and 62 g of chlorobenzene were added to a 1000 mL reactor. 123.2 g of N-methylimidazolium was added, the mixture was stirred, and the temperature was raised to 80 °C for 8 h. After the reaction was completed, the chlorobenzene and the remaining bromohexene were removed by external evaporation of the reaction solution. 132 g of dioxane was added, and the mixture was thoroughly mixed and allowed to stand for separation. The product layer was dried to obtain 236.9 g of 1-enhexyl-3-methylimidazolium bromide. HPLC analysis showed a purity of 99.87% and a yield of 96.77%.

[0022] Example 3: Preparation of 1-allyl-3-hexylimidazolium iodide 289.8 g of allyl iodide, 2.0 g of 2,6-di-tert-butyl-p-cresol, and 183 g of dichloroethane were added to a 1000 mL reactor. 228.4 g of N-hexylimidazole was added, and the mixture was stirred and heated to 70 °C for 2 h. After the reaction was completed, the dichloroethane and remaining allyl iodide were removed by external evaporation. 130 g of diethyl ether was added, and the mixture was thoroughly mixed and allowed to stand for separation. The product layer was dried to obtain 316.3 g of 1-allyl-3-hexylimidazole bromide. HPLC analysis showed a purity of 99.79% and a yield of 98.97%.

[0023] Example 4: Preparation of 1-enyl-3-methylimidazolium bromide 253.1 g of bromobutene, 1.3 g of 2,6-di-tert-butyl-p-cresol, and 62 g of hexafluoroisopropanol were added to a 1000 mL reactor. 123.2 g of N-methylimidazolium was added, the mixture was stirred, and the temperature was raised to 40 °C for 4 h. After the reaction was completed, the hexafluoroisopropanol and the remaining bromobutene were removed by external evaporation of the reaction solution. 126 g of tetrahydrofuran was added, and the mixture was thoroughly mixed and allowed to stand for separation. The product layer was dried to obtain 213.0 g of 1-allyl-3-methylimidazolium bromide. HPLC analysis showed a purity of 99.88% and a yield of 98.23%.

[0024] Example 5: Preparation of 1-allyl-3-dodecylimidazolium iodide 302.4 g of propylene iodide, 3.0 g of 2,6-di-tert-butyl-p-cresol, and 425 g of chlorobenzene were added to a 1000 mL reactor. 254.6 g of N-dodecylimidazolium was added, the mixture was stirred, and the temperature was raised to 60 °C for 3 h. After the reaction was completed, the chlorobenzene and the remaining propylene iodide were removed by external evaporation. 121 g of tetrahydrofuran was added, and the mixture was thoroughly mixed and allowed to stand for separation. The product layer was dried to obtain 398.0 g of 1-allyl-3-dodecylimidazolium bromide. HPLC analysis showed a purity of 99.85% and a yield of 98.57%.

[0025] Example 6: Preparation of 1-enpentyl-3-octylimidazolium bromide 312.9 g of bromopentene, 2.5 g of 2,6-di-tert-butyl-p-cresol, and 243 g of dichloroethane were added to a 1000 mL reactor. 270.4 g of N-octylimidazole was added, and the mixture was stirred and heated to 70 °C for 7 h. After the reaction was completed, the dichloroethane and remaining bromopentene were removed by external evaporation of the reaction solution. 188 g of dioxane was added, and the mixture was thoroughly mixed and allowed to stand for separation. The product layer was dried to obtain 317.4 g of 1-enpentyl-3-octylimidazole bromide. HPLC analysis showed a purity of 99.97% and a yield of 96.41%.

[0026] Example 7: Preparation of 1-allyl-3-methylimidazolium tetrafluoroborate 158.6 g of 1-allyl-3-methylimidazolium chloride and 109.8 g of sodium tetrafluoroborate prepared in Example 1 were added to a mixed solution of 146 g of water and 64 g of dichloromethane. The mixture was stirred and the temperature of the ultrasonic internal heating medium was set to 30 °C. The reaction was carried out for 0.5 h. After the reaction was completed, the mixture was allowed to stand and separate into layers. The aqueous phase was removed, and the organic phase was washed twice with water. After dichloromethane was externally distilled off, the mixture was dried in a vacuum oven to obtain 204.5 g of 1-allyl-3-methylimidazolium tetrafluoroborate. The purity was 99.78% and the yield was 97.59% as determined by HPLC.

[0027] Example 8: Preparation of 1-allyl-3-hexylimidazolium carbamate 320.2 g of 1-allyl-3-hexylimidazolium iodide and 102.0 g of sodium formate prepared in Example 3 were added to a mixed solution of 65 g of water and 128 g of dichloromethane. Stirring was started, and the temperature of the ultrasonic internal heating medium was set at 20°C. The reaction was carried out for 1 h. After the reaction was completed, the mixture was allowed to stand and separate into layers. The aqueous phase was removed, and the organic phase was washed twice with water. After dichloromethane was externally evaporated, the mixture was dried in a vacuum oven to obtain 235.0 g of 1-allyl-3-hexylimidazolium formate. The purity was 99.89% and the yield was 98.72% as determined by HPLC.

[0028] Example 9: Preparation of 1-enyl-3-methylimidazolium bicarbonate 217.11 g of 1-enbutyl-3-methylimidazolium bromide and 126.0 g of sodium bicarbonate prepared in Example 4 were added to a mixed solution of 90 g of water and 87 g of dichloromethane. Stirring was started, and the temperature of the ultrasonic internal heating medium was set at 30 °C. The reaction was carried out for 0.5 h. After the reaction was completed, the mixture was allowed to stand and separate into layers. The aqueous phase was removed, and the organic phase was washed twice with water. After dichloromethane was externally evaporated, the mixture was dried in a vacuum oven to obtain 195.9 g of 1-enbutyl-3-methylimidazolium bicarbonate. The purity was 99.65% and the yield was 99.17% as determined by HPLC.

[0029] Example 10: Preparation of 1-allyl-3-methylimidazolium dihydrogen phosphate 158.6 g of 1-allyl-3-methylimidazolium chloride and 204.1 g of potassium dihydrogen phosphate prepared in Example 1 were added to a mixed solution of 198 g of water and 64 g of dichloromethane. The mixture was stirred and the ultrasonic internal heating medium was set to 60 °C. The reaction was carried out for 0.5 h. After the reaction was completed, the mixture was allowed to stand and separate into layers. The aqueous phase was removed, and the organic phase was washed twice with water. After dichloromethane was externally evaporated, the mixture was dried in a vacuum oven to obtain 215.6 g of 1-allyl-3-methylimidazolium dihydrogen phosphate. The purity was 99.42% and the yield was 98.48% as determined by HPLC.

[0030] Example 11: Preparation of 1-enpentyl-3-octylimidazolium acetate 329.33 g of 1-allyl-3-octylimidazolium bromide and 98.1 g of potassium acetate prepared in Example 6 were added to a mixed solution of 154 g of water and 132 g of dichloromethane. The mixture was stirred and the ultrasonic internal heating medium was set to 50 °C. The reaction was carried out for 1.5 h. After the reaction was completed, the mixture was allowed to stand and separate into layers. The aqueous phase was removed, and the organic phase was washed three times with water. After dichloromethane was externally evaporated, the mixture was dried in a vacuum oven to obtain 304.8 g of 1-allyl-3-methylimidazolium acetate. The purity was 99.59% and the yield was 99.22% as determined by HPLC.

[0031] Example 12: Preparation of 1-allyl-3-hexylimidazolium bis(trifluoromethanesulfonyl)imide salt 320.2 g of 1-allyl-3-hexylimidazolium iodide and 303.1 g of sodium bis(trifluoromethanesulfonyl)imide prepared in Example 3 were added to a mixed solution of 95 g of water and 128 g of dichloromethane. The mixture was stirred and the ultrasonic internal heating medium was set to 25 °C. The reaction was carried out for 2.5 h. After the reaction was completed, the mixture was allowed to stand and separate into layers. The aqueous phase was removed, and the organic phase was washed three times with water. After dichloromethane was externally evaporated, the mixture was dried in a vacuum oven to obtain 456.2 g of 1-allyl-3-hexylimidazolium bis(trifluoromethanesulfonyl)imide. The purity was 99.62% and the yield was 96.72% as determined by HPLC.

[0032] Comparative Example 1: Preparation of 1-allyl-3-methylimidazolium chloride (Compared with Example 1, ether extraction was not used, otherwise the same as Example 1) 143.5 g of bromopropene, 0.7 g of 2,6-di-tert-butyl-p-cresol, and 62 g of hexafluoroisopropanol were added to a 500 mL reactor, along with 123.2 g of N-methylimidazolium. The mixture was stirred and heated to 30 °C for 3 h. After the reaction was completed, the hexafluoroisopropanol and the remaining bromopropene were removed by external evaporation, and the solution was dried to obtain 143.2 g of 1-allyl-3-methylimidazolium chloride. The purity was 91.38% and the yield was 98.77% as determined by HPLC.

[0033] Comparative Example 2: Preparation of 1-allyl-3-methylimidazolium tetrafluoroborate (Compared with Example 9, water was used instead of the mixed solvent, otherwise the same as Example 9) 158.6 g of 1-allyl-3-methylimidazolium chloride and 109.8 g of sodium tetrafluoroborate prepared in Example 1 were added to 90 g of water. Stirring was started, and the temperature of the ultrasonic internal heating medium was set at 30 °C. The reaction was carried out for 0.5 h. After the reaction was completed, the mixture was allowed to stand and separate into layers. The aqueous phase was removed, and the organic phase was washed twice with water. After dichloromethane was externally evaporated, the mixture was dried in a vacuum oven to obtain 163.8 g of 1-allyl-3-methylimidazolium tetrafluoroborate. The purity was 95.28% and the yield was 81.88% as determined by HPLC.

[0034] Comparative Example 3: Preparation of 1-enpentyl-3-octylimidazolium acetate (Compared with Example 11, dichloromethane was used instead of the mixed solvent, otherwise the same as Example 11) 329.33 g of 1-allyl-3-octylimidazolium bromide and 98.1 g of potassium acetate prepared in Example 8 were added to a mixed solution of 132 g of dichloromethane. Stirring was started, and the temperature of the ultrasonic internal heating medium was set at 50 °C. The reaction was carried out for 1.5 h. After the reaction was completed, 80 g of water was added to the reaction solution, mixed well, and allowed to stand for separation. The aqueous phase was removed, and the organic phase was washed three times with water. After distilling off the dichloromethane, the solution was dried in a vacuum oven to obtain 192.7 g of 1-allyl-3-methylimidazolium acetate. The purity was 95.86% and the yield was 65.17% as determined by HPLC.

[0035] Comparative Example 4: Preparation of 1-allyl-3-methylimidazolium dihydrogen phosphate (Compared with Example 10, but without the use of ultrasound-assisted reaction, otherwise the same as Example 10) 158.6 g of 1-allyl-3-methylimidazolium chloride and 204.1 g of potassium dihydrogen phosphate prepared in Example 1 were added to a mixed solution of 198 g of water and 64 g of dichloromethane. The mixture was stirred and heated to 60 °C for 0.5 h. After the reaction was completed, the mixture was allowed to stand and separate into layers. The aqueous phase was removed, and the organic phase was washed twice with water. After dichloromethane was externally evaporated, the mixture was dried in a vacuum oven to obtain 200.2 g of 1-allyl-3-methylimidazolium dihydrogen phosphate. The purity was 98.49% and the yield was 92.33% as determined by HPLC.

[0036] Compared with traditional preparation methods, the preparation method of the ionic liquid of this invention has a high raw material conversion rate and produces a high-purity 1-alkenyl-3-alkylimidazolium halide ionic liquid product. The preparation method of 1-alkenyl-3-alkylimidazolium ionic liquid is simple and conducive to industrial production by adding ultrasonic-assisted equipment, reducing the reaction temperature, reducing the amount of mixed solvent, and separating inorganic salt by-products in one step.

[0037] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A functionalized ionic liquid, characterized in that, It has the following general chemical structural formula: ， Where n is 1, 2, 4, 6, 8, 10, or 12, m is 1 to 4, and X is anion with the following structure: Cl - ,Br - I - BF4 - PF6 - HSO4 - HCO3 - H2PO4 - NO3 - CH3COO - CF3SO3 - (CF3SO2)3C - Ts - TFSI - or SCN - .

2. A method for preparing the functionalized ionic liquid according to claim 1, characterized in that, When the anion is Cl - ,Br - Or I - The preparation method is as follows: alkylimidazolium, haloalkene, polymerization inhibitor and reaction solvent are mixed in a certain proportion and reacted at 30~80℃ for 2~8h; the reaction solvent and most of the unreacted haloalkane are distilled off from the reaction liquid, the extraction solvent is added, mixed well, allowed to stand and separated, and a small amount of unreacted haloalkane is separated; the crude product after separation is dried to obtain 1-alkenyl-3-alkylimidazolium halide ionic liquid.

3. A method for preparing the functionalized ionic liquid according to claim 1, characterized in that, The anion is BF4. - PF6 - HSO4 - HCO3 - H2PO4 - NO3 - CH3COO - CF3SO3 - (CF3SO2)3C - Ts - TFSI - or SCN - The preparation method is as follows: Sodium or potassium salt containing anions and 1-alkenyl-3-alkylimidazolium halide ionic liquid are added to a mixed solvent in a 1:1 molar ratio. The reaction is assisted by ultrasound and carried out for 1-3 hours. After standing and separating the layers, the halide salt is separated. The organic phase is washed with water and dried under vacuum to obtain a series of 1-alkenyl-3-alkylimidazolium ionic liquids.

4. The preparation method according to claim 2, characterized in that, The molar ratio of alkylimidazolium to haloalkene is 1:1.05~1.

5.

5. The preparation method according to claim 2, characterized in that, The polymerization inhibitor is one of hydroquinone, p-hydroxyanisole, p-tert-butylcatechol, 2,6-di-tert-butyl-p-cresol, benzoquinone, or TEMPO, and the amount used is 0.5% to 1% of the mass of the haloolefin.

6. The preparation method according to claim 2, characterized in that, The reaction solvent is an organic halogenated solvent, which is one or more of dichloromethane, chloroform, carbon tetrachloride, dichloroethane, trifluoroethanol, hexafluoroisopropanol, trifluoroacetic acid, thionyl chloride, trifluorotoluene, and chlorobenzene, and the amount used is 0.5 to 1.2 times the mass of the alkylimidazole.

7. The preparation method according to claim 2, characterized in that, The extraction solvent is one or more of the following: diethyl ether, petroleum ether, n-hexane, cyclohexane, methyl tert-butyl ether, tetrahydrofuran, dioxolane, and dioxane, and the amount used is 0.3 to 0.7 times the mass of the haloolefin.

8. The preparation method according to claim 3, characterized in that, The mixed solvent is water and dichloromethane, with water accounting for B and dichloromethane accounting for 0.3 to 0.5 times the mass of the 1-alkenyl-3-alkylimidazolium halide ionic liquid.

9. The preparation method according to claim 8, characterized in that, B = (0.8~1.0)a, where B is the actual mass of water used in the reaction, and a is the mass of water required to prepare a saturated halide salt solution at room temperature.

10. The preparation of the functionalized ionic liquid according to claim 3, characterized in that, The ultrasonic heating temperature is 20~60℃.

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