Quaternary amine ionic liquid with double epoxy arms as well as preparation method and application of quaternary amine ionic liquid

Abstract

The invention discloses a double epoxy arm quaternary amine ionic liquid as well as a preparation method and application thereof. The structural formula is shown in the specification, wherein X is Cl or TFSI; n is 1, 2 or 3. Pyrrolidine and halogenated hydrocarbon are used as raw materials and react in alkali and anhydrous acetonitrile under the protection of nitrogen, and the halogen anion diepoxy arm quaternary amine ionic liquid is prepared through rotary evaporation, precipitator washing and vacuum drying. And carrying out anion exchange on the TFSI and a LiTFSI aqueous solution, layering and drying to obtain the TFSI anion double epoxy arm quaternary amine ionic liquid. The product disclosed by the invention has controllable molecular flexibility and polarity, and can be used for a doped PEDOT: PSS system by balancing hydrophilic and hydrophobic properties, so that the conductivity and stretchability of the composite film are enhanced.

Description

Technical Field

[0001] The present invention belongs to the field of ionic liquid preparation, and in particular relates to a preparation method and application of a bis-epoxy-arm quaternary ammonium ionic liquid. Background Art

[0002] The introduction of the TFSI anion significantly enhances the conductivity of PEDOT:PSS. Due to its large size and dispersed charge, TFSI is relatively hydrophobic. Common commercially available TFSI anionic liquids are highly hydrophobic, making it difficult to mix with the PH1000 aqueous solution system to enhance its performance. Summary of the Invention

[0003] The purpose of the present invention is to provide a novel bis-epoxy-arm quaternary ammonium ionic liquid, a preparation method and an application thereof, so as to improve the problem of limited types of current functional ionic liquids.

[0004] In order to achieve the above-mentioned purpose, the present invention adopts the following technical solutions.

[0005] The bis-epoxy-arm quaternary ammonium ionic liquid of the present invention is characterized in that its structural formula is as shown in the formula:

[0006] Wherein X is Cl or TFSI; n is 1, 2 or 3.

[0007] The method for preparing a bis-epoxy-arm quaternary ammonium ionic liquid according to the present invention is characterized by comprising the following steps.

[0008] (1) Pyrrolidine monomer, halogenated hydrocarbon monomer and alkaline agent are dissolved in anhydrous acetonitrile, wherein the molar ratio of pyrrolidine monomer to halogenated hydrocarbon monomer is 1:2~1:6.

[0009] (2) Add the mixed solution of step (1) into a flask equipped with a mechanical stirrer and a condenser, maintain the reaction temperature at 50-90°C, and react under nitrogen protection for 24-96 hours.

[0010] (3) The reaction solution in step (2) is subjected to rotary evaporation to remove the solvent, and the solution is poured into a precipitant having a volume 3 to 5 times greater than the volume of the solution to precipitate the solution, and the precipitate is washed three times with the precipitant.

[0011] (4) The clean precipitate in step (3) is spin-dried and vacuum-dried at 40-60° C. for 12-24 h to obtain a halogen anion diepoxy arm quaternary ammonium ionic liquid.

[0012] (5) The halogen anion diepoxy arm quaternary ammonium ionic liquid described in step (4) is mixed with a 30 wt% LITFSI aqueous solution, stirred for 1 to 2 h, allowed to stand for stratification, the lower layer of liquid is taken, and dried to obtain a diepoxy arm quaternary ammonium ionic liquid with TFSI as the counter anion.

[0013] The reaction equation involved in the present invention is as follows:

[0014] Furthermore, the halogenated hydrocarbon monomer in step (1) is selected from any one of 2-(2-chloroethoxy)ethylamine, 2-(2-chloroethoxy)ethanol, 2-[2-(2-chloroethoxy)ethoxy]ethanol, 2-(2-(2-chloroethoxy)ethoxy)ethoxy)ethanol, and similar halogenated hydrocarbon compounds.

[0015] Furthermore, the alkaline agent in step (1) is selected from any one of potassium bicarbonate, potassium carbonate, etc.

[0016] Furthermore, the reaction temperature in step (2) is preferably 80° C., the reaction time is preferably 72 h, and the molar ratio of the pyrrolidine monomer to the halogenated hydrocarbon monomer is preferably 1:3.

[0017] Furthermore, the precipitant in step (3) is selected from any one of toluene or ethyl acetate.

[0018] The invention discloses an application of a novel bis-epoxy-arm quaternary ammonium ionic liquid in enhancing the electrical conductivity and stretchability of a PEDOT:PSS film.

[0019] Mix a di-epoxy-arm quaternary ammonium ionic liquid (DIQIL) and PH1000, where the DIQIL concentration is 10 wt% to 70 wt% of the PEDOT:PSS mass. Apply the mixed solution on a glass slide and dry at 60°C for 2 h to form a film.

[0020] The novel bis-epoxy-arm quaternary ammonium ionic liquid prepared in this invention exhibits tunable molecular flexibility and polarity. For example, increasing the epoxy arm length can enhance molecular flexibility; -OH and -NH2 endcapping can enhance hydrophilicity; and the choice of anion plays a key role in regulating hydrophilicity and hydrophobicity. Leveraging its tunable molecular flexibility and polarity, this TFSI anionic bis-epoxy-arm quaternary ammonium ionic liquid can be used for secondary doping of PEDOT:PSS (PH1000), promoting decoupling of PEDOT and PSS through ion exchange, and synergistically improving the conductivity and stretchability of the film.

[0021] The beneficial effects of the present invention are as follows: The key to this invention is the use of halogenated hydrocarbons to functionalize the nitrogen atoms on pyrrolidine with quaternary ammonium. The flexibility of the ionic liquid is adjusted by adjusting the length of the epoxy arm in the halogenated hydrocarbon, while the hydrophilicity of the ionic liquid is adjusted by adjusting the end group on the other side of the halogenated hydrocarbon. Functional anion replacement is achieved through anion exchange.

[0022] Compared with other technologies, the novel diepoxy-arm quaternary ammonium ionic liquid prepared in the present invention has controllable molecular flexibility and polarity. By balancing hydrophilicity and hydrophobicity, it can be used to dope the PEDOT:PSS system to enhance the conductivity and stretchability of the composite film. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is the H spectrum of the chloride anion-terminated hydroxyl-diepoxide-arm quaternary ammonium ionic liquid prepared in Example 1.

[0024] Figure 2 This is the C spectrum of the chloride anion-terminated hydroxyl-diepoxide-arm quaternary ammonium ionic liquid prepared in Example 2. DETAILED DESCRIPTION

[0025] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. Example 1

[0026] Preparation of chloride anion-terminated hydroxyl-diepoxide-arm quaternary ammonium ionic liquid.

[0027] (1) Pyrrolidine monomer and 2-(2-chloroethoxy)ethanol monomer are dissolved in anhydrous acetonitrile, and solid potassium carbonate is added thereto.

[0028] (2) A flask equipped with a mechanical stirrer, a condenser, and a mixed solution was placed under nitrogen at 80°C for 72 h. The molar ratio of pyrrolidine, 2-(2-chloroethoxy)ethanol, and potassium carbonate was 1:3:10.

[0029] (3) The reaction solution in step (2) was evaporated to remove the solvent, poured into toluene with a volume three times larger than the volume of the reaction solution to precipitate, and the precipitate was washed three times with a precipitant.

[0030] (4) The clean precipitate in step (3) was spin-dried and vacuum-dried at 60° C. for 12 h to obtain a chloride anion-terminated hydroxyl-terminated diepoxy arm quaternary ammonium ionic liquid.

[0031] Compound structure confirmation: The H spectrum data of the chloride anion-terminated hydroxyl-terminated diepoxy-arm quaternary ammonium ionic liquid prepared in the example are as follows Figure 1 As shown, the C spectrum data is as follows Figure 2 shown. Example 2

[0032] The preparation method is the same as that of Example 1, except that the reaction temperature of step (2) is changed and its effect on the reaction is tested, as shown in Table 1: Table 1

[0033] Analysis: As shown in Table 1, when the reaction temperature is low, the yield of the reaction is not high. As the reaction temperature increases, the yield increases rapidly. The optimal reaction temperature is 80°C. Example 3

[0034] The preparation method is the same as that of Example 1, except that the reaction time of step (2) is changed, and its effect on the reaction is tested, as shown in Table 2: Table 2

[0035] Analysis: As shown in Table 2, when the reaction time is short, the yield of the reaction is not high. As the reaction time increases, the yield gradually increases. The optimal reaction time is 72 h. Example 4

[0036] The preparation method is the same as that of Example 1, except that the molar ratio of pyrrolidine and 2-(2-chloroethoxy)ethanol in step (2) is changed, and the effect on the reaction is tested as shown in Table 3: Table 3

[0037] Analysis: As shown in Table 3, when the molar ratio of pyrrolidine to 2-(2-chloroethoxy)ethanol changes, the yield increases significantly with the increase of 2-(2-chloroethoxy)ethanol feed, and the optimal molar ratio is 1:3. Example 5

[0038] Preparation of TFSI anion-terminated hydroxyl-diepoxide-arm quaternary ammonium ionic liquid.

[0039] (1) Pyrrolidine monomer and 2-(2-chloroethoxy)ethanol monomer are dissolved in anhydrous acetonitrile, and solid potassium carbonate is added thereto.

[0040] (2) A flask equipped with a mechanical stirrer, a condenser, and a mixed solution was placed under nitrogen at 80°C for 72 h. The molar ratio of pyrrolidine, 2-(2-chloroethoxy)ethanol, and potassium carbonate was 1:3:10.

[0041] (3) The reaction solution in step (2) was evaporated to remove the solvent, poured into toluene with a volume three times larger than the volume of the reaction solution to precipitate, and the precipitate was washed three times with a precipitant.

[0042] (4) The clean precipitate in step (3) was spin-dried and vacuum-dried at 60° C. for 12 h to obtain a chloride anion-terminated hydroxyl-terminated diepoxy arm quaternary ammonium ionic liquid.

[0043] (5) The chloride anion-terminated hydroxyl-diepoxy-arm quaternary ammonium ionic liquid described in step (4) is mixed with a 30 wt% LITFSI aqueous solution, stirred for 1 to 2 h, allowed to stand for stratification, the lower layer of liquid is taken, and dried to obtain the TFSI anion-terminated hydroxyl-diepoxy-arm quaternary ammonium ionic liquid.

[0044] Application Examples

[0045] Mix 60 wt% of a chloride anion-terminated hydroxyl-diepoxy-arm quaternary ammonium ionic liquid or 45 wt% of the corresponding TFSI anion-terminated hydroxyl-diepoxy-arm quaternary ammonium ionic liquid with a PH1000 aqueous solution. Apply the mixed solution dropwise onto a glass slide and dry at 60°C for 2 h to form a film.

[0046] Performance test: The prepared chloride anion-terminated hydroxyl-terminated bi-epoxy-arm quaternary ammonium ionic liquid doped PEDOT composite film was tested at 0.5 mm min -1 At a tensile rate of 1.5, the film's elongation at break reached 22.29% and its electrical conductivity reached 165 S cm -1 The PEDOT:PSS composite film doped with TFSI anion-terminated hydroxyl-diepoxide-arm quaternary ammonium ionic liquid has an elongation at break of 34.56% and an electrical conductivity of 879 S cm -1 .

[0047] Summary: The above results demonstrate that the novel diepoxy-arm quaternary ammonium ionic liquid prepared in the present invention has tunable molecular flexibility and polarity. By balancing hydrophilicity and hydrophobicity, it can be used to dope the PEDOT:PSS system, significantly enhancing the electrical conductivity and stretchability of the composite film.

Claims

1. A bis-epoxide-arm quaternary ammonium ionic liquid, characterized in that The structural formula is shown as follows: ， Wherein, X is Cl or TFSI; n is 1, 2 or 3.

2. The method for preparing a bis-epoxide arm quaternary ammonium ionic liquid according to claim 1, wherein The following steps are involved: (1) Pyrrolidine monomer, halogenated hydrocarbon monomer and alkaline agent are dissolved in anhydrous acetonitrile, wherein the molar ratio of pyrrolidine monomer to halogenated hydrocarbon monomer is 1:2 to 1:6; (2) Add the mixed solution of step (1) into a flask equipped with a mechanical stirrer and a condenser, maintain the reaction temperature at 50-90°C, and react under nitrogen protection for 24-96 hours; (3) The reaction solution in step (2) is subjected to rotary evaporation to remove the solvent, and the solution is poured into a precipitant having a volume 3 to 5 times greater than the volume of the solution to precipitate the solution, and the precipitate is washed three times with the precipitant; (4) The clean precipitate in step (3) is spin-dried and vacuum-dried at 40-60° C. for 12-24 h to obtain a halogen anion diepoxy arm quaternary ammonium ionic liquid; (5) The halogen anion diepoxy arm quaternary ammonium ionic liquid described in step (4) is mixed with a 30 wt% LITFSI aqueous solution, stirred for 1 to 2 h, allowed to stand for stratification, the lower layer of liquid is taken, and dried to obtain a diepoxy arm quaternary ammonium ionic liquid with TFSI as the counter anion.

3. The method for preparing a bis-epoxide arm quaternary ammonium ionic liquid according to claim 2, wherein The halogenated hydrocarbon monomer in step (1) is any one of 2-(2-chloroethoxy)ethylamine, 2-(2-chloroethoxy)ethanol, 2-[2-(2-chloroethoxy)ethoxy]ethanol or 2-(2-(2-chloroethoxy)ethoxy)ethoxy)ethanol.

4. The method for preparing a bis-epoxide arm quaternary ammonium ionic liquid according to claim 2, wherein: The alkaline agent described in step (1) is any one of potassium bicarbonate or potassium carbonate.

5. The method for preparing a bis-epoxide arm quaternary ammonium ionic liquid according to claim 2, wherein: The reaction temperature in step (2) is 80° C., the reaction time is 72 h, and the molar ratio of the pyrrolidine monomer to the halogenated hydrocarbon monomer is 1:

3.

6. The method for preparing a bis-epoxide arm quaternary ammonium ionic liquid according to claim 2, wherein: The precipitant in step (3) is toluene or ethyl acetate.

7. Use of the novel bis-epoxy-arm quaternary ammonium ionic liquid according to claim 1 in enhancing the electrical conductivity and stretchability of PEDOT:PSS films.

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