Ionic liquid catalyst prepared by simple ion exchange method and application thereof

Abstract

The invention discloses an ionic liquid catalyst prepared by a simple ion exchange method and application of the ionic liquid catalyst, and belongs to the field of catalyst material preparation. The ionic liquid catalyst is prepared by simply combining different cationic donors and anionic donors by using an ionic combination method, the preparation steps are simple, the obtained catalyst can be used for cycloaddition reaction of epoxide and carbon dioxide, the raw material conversion rate is high, and the catalyst is suitable for industrial production. The preparation steps of the catalyst in the CO2 cycloaddition field can be simplified, and the reaction activity of the catalyst can be improved.

Description

Technical Field

[0001] The invention belongs to the field of catalyst material preparation, and in particular relates to a method for simply preparing an ionic liquid catalyst by utilizing anion and cation exchange of ionic liquid. Background Art

[0002] Global warming is one of the major environmental issues facing the world today. Excessive emissions of carbon dioxide, as the main greenhouse gas, are an important cause of global warming. Moreover, with the acceleration of industrialization and the continuous increase of human activities, carbon dioxide emissions continue to rise, posing a serious threat to the earth's ecological environment and human survival and development. Therefore, controlling carbon dioxide emissions has become an urgent task faced by all countries in the world.

[0003] So far, two main strategies have been adopted to solve this problem: one is to capture and store CO2 or convert it into valuable chemicals, thereby treating CO2 as a safe, abundant, renewable and cheap C1 energy source; the other is to cycloaddition CO2 with epoxides to generate cyclic carbonates. From the perspective of green chemistry metrics, the second route is very attractive because it has 100% atom efficiency and does not require solvents.

[0004] Ionic liquids are organic salts that are liquid at room temperature and are composed of organic cations and inorganic or organic anions. They have the characteristics of almost no vapor pressure, non-flammability, non-volatility, good chemical stability and thermal stability, recyclability and environmental friendliness, and their properties can be changed by changing the structure of cations and anions. Ionic liquids have unique advantages and characteristics as catalysts in epoxide cycloaddition reactions. However, there are certain disadvantages in the preparation process of ionic liquid catalysts. For example, the preparation of certain ionic liquids has requirements for reaction temperature and pressure. The biimidazole ionic liquid prepared in patent CN112778124A not only needs to be refluxed at 80°C for 4 hours, but also needs to be washed with toluene and ether. At the same time, the cation donor biimidazole sulfonic acid compound in the ionic liquid also needs to be prepared using imidazole compounds through complex steps, which greatly increases the difficulty and cost of preparing the catalyst. Meanwhile, in the common ionic liquid catalyzed synthesis of cyclic carbonates, as mentioned in patent CN108440487A, although it has different catalytic effects on different epoxides, different co-catalysts need to be added to catalyze the reaction, and the cation donors used have C side chains, which will increase the steric effect of the catalyst and reduce the catalytic activity. Therefore, how to simplify the preparation scheme of ionic liquids and use them in the cycloaddition reaction of carbon dioxide is a research difficulty. Summary of the invention

[0005] In order to overcome the problems of complicated preparation steps and low reaction activity of existing catalytic ionic liquid catalysts, the present invention provides a method for simply preparing ionic liquid catalysts using anion and cation combination method of ionic liquids, and using the method to catalyze the cycloaddition reaction of epoxides and carbon dioxide.

[0006] To achieve the above object, the present invention adopts the following technical solution: A method for preparing an ionic liquid catalyst by a simple ion exchange method, which uses a cation donor containing a desired cation as a raw material, utilizes the characteristics of cations with positive charges and anions with negative charges, causes them to attract each other through electrostatic attraction and combine, and then ion exchange occurs, thereby preparing the ionic liquid catalyst. It specifically includes the following steps: 1) Slowly add the anion donor to the cation donor and stir the reaction at room temperature; 2) The reaction solution obtained in step 1) is dehydrated and then dried to obtain the ionic liquid catalyst.

[0007] Furthermore, the molar ratio of the cation donor to the anion donor used in step 1) is 1:1-6.

[0008] Furthermore, the cation donor is biimidazole (BIM, )、1,2,4-triazole(TAZ, )、triethylenediamine(DABCO, )

[0009] Furthermore, the anion donor is one of HBr, HCl, HI, HBF4, and KPF6.

[0010] Furthermore, the stirring reaction time in step 1) is 12 to 24 hours.

[0011] The ionic liquid catalyst prepared by the method can be used to catalyze the cycloaddition reaction of CO2 and epoxides such as styrene oxide.

[0012] Furthermore, the temperature of the cycloaddition reaction is 100-120° C., the pressure is 1-1.2 MPa, and the time is 12 h.

[0013] The present invention has the following beneficial effects: (1) The present invention forms a new ionic liquid catalyst by a simple ion exchange method by utilizing the characteristics of the charges of anions and cations themselves to carry out ion exchange in the form of ion binding to achieve the combination of different anion and cation donors.

[0014] (2) The ionic liquid catalyst prepared by this method can not only effectively solve the problems of complex preparation and low reaction activity of existing catalysts, but also can be combined to prepare catalysts with different catalytic sites by adjusting different anions and cations; in addition, this method also has a certain universality and can be used to combine a variety of anion and cation liquids.

[0015] (3) The ionic liquid catalyst prepared by the present invention can be used for the cycloaddition reaction of styrene oxide and CO2, and exhibits excellent catalytic performance and good effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 The infrared spectra of the ionic liquid catalysts prepared in Examples 1 to 3 are shown.

[0017] Figure 2 This is the thermogravimetric analysis diagram of the ionic liquid catalyst prepared in Examples 1 to 3. DETAILED DESCRIPTION

[0018] A method for preparing an ionic liquid catalyst by a simple ion exchange method, the steps of which are as follows: 1) Place the cation donor in a flask, then slowly add the anion donor dropwise at a molar ratio of 1:1-6, and stir at room temperature for 12-24 h; 2) The reaction solution obtained in step 1) is first placed in a common oven to remove water, and then placed in a vacuum drying oven to dry, and the obtained solid is the ionic liquid catalyst.

[0019] Wherein, the cation donor is one of biimidazole, 1,2,4-triazole, and triethylenediamine. The anion donor is one of HBr, HCl, HI, HBF4, and KPF6.

[0020] The obtained ionic liquid catalyst can be applied to the cycloaddition reaction of CO2 and styrene oxide. The typical operation is to introduce a certain amount of styrene oxide and ionic liquid catalyst into a reactor equipped with a magnetic stirrer, carefully seal the reactor, purge the reactor with CO2 gas three times to remove residual air and moisture in the atmosphere, and then fill CO2 to maintain the reactor pressure at 1-1.2MPa, set the temperature to 100-120°C, start stirring, and react for 12 hours at a speed of 400rpm. After the reaction is completed, the reactor is cooled to below 10°C using an ice water bath, and the excess gas in the reactor is slowly released until the reactor returns to normal pressure.

[0021] In order to make the contents of the present invention easier to understand, the technical solution of the present invention is further described below in conjunction with specific implementation methods, but the present invention is not limited thereto.

[0022] Example 1 Accurately weigh 0.05 mol triethylenediamine (DABCO) in a 25 mL round-bottom flask, add 0.05 mol HBr dropwise under magnetic stirring, and stir at room temperature for 24 h to obtain a white viscous substance. The stirred mixture is first placed in a common oven at 80°C to remove water for 4 h, and then vacuum dried to obtain the [DABCO][Br] catalyst.

[0023] Example 2 Accurately weigh 0.05 mol of 1,2,4-triazole (TAZ) in a 25 mL round-bottom flask, add 0.05 mol HBr dropwise under magnetic stirring, and stir at room temperature for 24 h to obtain a yellow viscous substance. The stirred mixture is first placed in a common oven at 80°C to remove water for 4 h, and then vacuum dried to obtain the [TAZ][Br] catalyst.

[0024] Example 3 Accurately weigh 0.05 mol of biimidazole (BIM) in a 25 mL round-bottom flask, add 0.05 mol HBr dropwise under magnetic stirring, and stir at room temperature for 24 h to obtain a gray viscous substance. The stirred mixture is first placed in a common oven at 80°C to remove water for 4 h, and then vacuum dried to obtain the [BIM][Br] catalyst.

[0025] Figure 1 The infrared spectra of the ionic liquid catalysts prepared in Examples 1 to 3 are shown in FIG. As shown in the figure, the synthesized [DABCO][Br] catalyst has a wavelength of 1161-984 cm-1 compared to DABCO. -1 and 2785-2981 cm -1 There is no obvious abnormality in the characteristic peak at [DABCO][Br], indicating that [DABCO][Br] still retains the original structure of the cation. Similarly, it can be seen that for the synthesized [BIM][Br] and [TAZ][Br] catalysts, their wavelengths are 1330-1100 cm-1 compared with BIM and TAZ. -1 1550-1400cm -1 The characteristic peak and wavelength of BIM are 1200-1100 cm -1 , 1400-1300 cm -1 and 1650-1600 cm -1 There is no obvious abnormality in the characteristic peaks of TAZ, indicating that the original structure of the cation is retained.

[0026] Figure 2The thermogravimetric analysis diagram of the ionic liquid catalyst prepared in Examples 1 to 3. It can be seen from the figure that the prepared [TAZ][Br] catalyst has obvious weight loss at 175°C, the [BIM][Br] catalyst has obvious weight loss at 250°C, and the [DABCO][Br] catalyst has obvious weight loss at 300°C. Considering that the temperature of the reaction system used by the catalyst is 110°C, the prepared catalyst can still have good stability in the reaction system.

[0027] Example 4 Accurately weigh 0.05 mol DABCO in a 25 mL round-bottom flask, add 0.3 mol HBF4 dropwise under magnetic stirring, and stir at room temperature for 12 h to obtain a white viscous substance. The stirred mixture is first placed in a common oven at 80°C to remove water for 4 h, and then vacuum dried to obtain the [DABCO][BF4] catalyst.

[0028] Example 5 Accurately weigh 0.05 mol DABCO in a 25 mL round-bottom flask, add 0.15 mol KPF6 dropwise under magnetic stirring, and stir at room temperature for 24 h to obtain a white viscous substance. The stirred mixture is first placed in a common oven at 80°C to remove water for 4 h, and then vacuum dried to obtain the [DABCO][PF6] catalyst.

[0029] Example 6 Accurately weigh 0.05 mol TAZ in a 25 mL round-bottom flask, add 0.05 mol HI dropwise under magnetic stirring, and stir at room temperature for 24 h to obtain a yellow viscous substance. The stirred mixture is first placed in a common oven at 80°C to remove water for 4 h, and then vacuum dried to obtain [TAZ][I] catalyst.

[0030] Example 7 Accurately weigh 0.05 mol BIM in a 25 mL round-bottom flask, add 0.05 mol HCl dropwise under magnetic stirring, and stir at room temperature for 24 h to obtain a gray viscous substance. The stirred mixture is first placed in a common oven at 80°C to remove water for 4 h, and then vacuum dried to obtain the [BIM][Cl] catalyst.

[0031] Example 8 Accurately weigh 0.05 mol DABCO in a 25 mL round-bottom flask, add 0.05 mol HCl dropwise under magnetic stirring, and stir at room temperature for 24 h to obtain a gray viscous substance. The stirred mixture is first placed in a common oven at 80°C to remove water for 4 h, and then vacuum dried to obtain the [DABCO][Cl] catalyst.

[0032] Application Example 1 Application of the ionic liquid catalyst prepared by a simple ion exchange method in the cycloaddition reaction of epoxide and carbon dioxide: Weigh 0.024 g of the [DABCO][Br] catalyst prepared in Example 1 and put it into a parallel reactor containing 4 mmol of styrene oxide, which is equipped with a magnetic stirrer and has a volume of 10 mL. After the reactor is carefully sealed, it is purged with CO2 gas three times to remove the residual gas in the reactor, and then filled with CO2 to maintain the pressure of the reactor at 1.1 MPa, and the reaction temperature is set to 110°C, stirring is turned on, and the reaction is carried out at a speed of 400 rpm for 12 h. After the reaction is completed, the reactor is cooled to below 10°C using an ice water bath, and the excess gas in the reactor is slowly released until the reactor returns to normal pressure. After the reaction is completed, a gas chromatograph is used for quantitative analysis.

[0033] It has been determined that under the above reaction conditions, the conversion rate of the cycloaddition of styrene oxide catalyzed by [DABCO][Br] catalyst is 100%, and the yield of the product styrene cyclic carbonate is over 92.1%.

[0034] Application Example 2 Application of the ionic liquid catalyst prepared by the simple ion exchange method in the cycloaddition reaction of epoxide and carbon dioxide: Weigh 0.024 g of the [DABCO][Br] catalyst prepared in Example 1 and put it into a parallel reactor containing 4 mmol of styrene oxide, which is equipped with a magnetic stirrer and has a volume of 10 mL. After the reactor is carefully sealed, it is purged with CO2 gas three times to remove the residual gas in the reactor, and then filled with CO2 to maintain the pressure of the reactor at 1.1 MPa. The reaction temperature is set to 100°C, stirring is turned on, and the reaction is carried out at a speed of 400 rpm for 12 h. After the reaction is completed, the reactor is cooled to below 10°C using an ice water bath, and the excess gas in the reactor is slowly released until the reactor returns to normal pressure. After the reaction is completed, a gas chromatograph is used for quantitative analysis.

[0035] It has been determined that under the above reaction conditions, the conversion rate of the cycloaddition of styrene oxide catalyzed by [DABCO][Br] catalyst is 100%, and the yield of the product styrene cyclic carbonate is over 84.6%.

[0036] Application Example 3 Application of the ionic liquid catalyst prepared by the simple ion exchange method in the cycloaddition reaction of epoxide and carbon dioxide: Weigh 0.024 g of the [DABCO][Br] catalyst prepared in Example 1 and put it into a parallel reactor containing 4 mmol of styrene oxide, which is equipped with a magnetic stirrer and has a volume of 10 mL. After the reactor is carefully sealed, it is purged with CO2 gas three times to remove the residual gas in the reactor, and then filled with CO2 to maintain the reactor pressure at 1 MPa, and the reaction temperature is set to 110°C, stirring is turned on, and the reaction is carried out at a speed of 400 rpm for 12 h. After the reaction is completed, the reactor is cooled to below 10°C using an ice water bath, and the excess gas in the reactor is slowly released until the reactor returns to normal pressure. After the reaction is completed, a gas chromatograph is used for quantitative analysis.

[0037] It has been determined that under the above reaction conditions, the conversion rate of the cycloaddition of styrene oxide catalyzed by [DABCO][Br] catalyst is 100%, and the yield of the product styrene cyclic carbonate is over 91.9%.

[0038] Application Example 4: Application of ionic liquid catalyst prepared by simple ion exchange method in cycloaddition reaction of epoxide and carbon dioxide: Weigh 0.024 g of the [DABCO][Br] catalyst prepared in Example 1 and put it into a parallel reactor containing 4 mmol of styrene oxide, which is equipped with a magnetic stirrer and has a volume of 10 mL. After the reactor is carefully sealed, it is purged with CO2 gas three times to remove the residual gas in the reactor, and then filled with CO2 to maintain the reactor pressure at 1.2 MPa, and the reaction temperature is set to 110°C, stirring is turned on, and the reaction is carried out at a speed of 400 rpm for 12 h. After the reaction is completed, the reactor is cooled to below 10°C using an ice water bath, and the excess gas in the reactor is slowly released until the reactor returns to normal pressure. After the reaction is completed, a gas chromatograph is used for quantitative analysis.

[0039] It has been determined that under the above reaction conditions, the conversion rate of the cycloaddition of styrene oxide catalyzed by [DABCO][Br] catalyst is 100%, and the yield of the product styrene cyclic carbonate is over 91.8%.

[0040] Application Example 5: Application of ionic liquid catalyst prepared by simple ion exchange method in cycloaddition reaction of epoxide and carbon dioxide: Weigh 0.024 g of the [TAZ][Br] catalyst prepared in Example 2 and put it into a parallel reactor containing 4 mmol of styrene oxide, which is equipped with a magnetic stirrer and has a volume of 10 mL. After the reactor is carefully sealed, it is purged with CO2 gas three times to remove the residual gas in the reactor, and then filled with CO2 to maintain the reactor pressure at 1.1 MPa, and the reaction temperature is set to 110°C, stirring is turned on, and the reaction is carried out at a speed of 400 rpm for 12 h. After the reaction is completed, the reactor is cooled to below 10°C using an ice water bath, and the excess gas in the reactor is slowly released until the reactor returns to normal pressure. After the reaction is completed, a gas chromatograph is used for quantitative analysis.

[0041] It has been determined that under the above reaction conditions, the conversion rate of the cycloaddition of styrene oxide catalyzed by [TAZ][Br] catalyst is 95.7%, and the yield of the product styrene cyclic carbonate is over 73.0%.

[0042] Application Example 6: Application of ionic liquid catalyst prepared by simple ion exchange method in cycloaddition reaction of epoxide and carbon dioxide: Weigh 0.024 g of the [BIM][Br] catalyst prepared in Example 3 and put it into a parallel reactor containing 4 mmol of styrene oxide, which is equipped with a magnetic stirrer and has a volume of 10 mL. After the reactor is carefully sealed, it is purged with CO2 gas three times to remove the residual gas in the reactor, and then filled with CO2 to maintain the reactor pressure at 1.1 MPa, and the reaction temperature is set to 110°C, stirring is turned on, and the reaction is carried out at a speed of 400 rpm for 12 h. After the reaction is completed, the reactor is cooled to below 10°C using an ice water bath, and the excess gas in the reactor is slowly released until the reactor returns to normal pressure. After the reaction is completed, a gas chromatograph is used for quantitative analysis.

[0043] It has been determined that under the above reaction conditions, the conversion rate of the cycloaddition of styrene oxide catalyzed by [BIM][Br] catalyst is 90.7%, and the yield of the product styrene cyclic carbonate is over 62.1%.

[0044] Application Example 7: Application of ionic liquid catalyst prepared by simple ion exchange method in cycloaddition reaction of epoxide and carbon dioxide: Weigh 0.024 g of the [DABCO][BF4] catalyst prepared in Example 4 and put it into a parallel reactor containing 4 mmol of styrene oxide, which is equipped with a magnetic stirrer and has a volume of 10 mL. After the reactor is carefully sealed, it is purged with CO2 gas three times to remove the residual gas in the reactor, and then filled with CO2 to maintain the reactor pressure at 1.1 MPa, and the reaction temperature is set to 110°C, stirring is turned on, and the reaction is carried out at a speed of 400 rpm for 12 h. After the reaction is completed, the reactor is cooled to below 10°C using an ice water bath, and the excess gas in the reactor is slowly released until the reactor returns to normal pressure. After the reaction is completed, a gas chromatograph is used for quantitative analysis.

[0045] It has been determined that under the above reaction conditions, the conversion rate of the cycloaddition of styrene oxide catalyzed by [DABCO][BF4] catalyst is 96.9%, and the yield of the product styrene cyclic carbonate is over 65.2%.

[0046] Application Example 8: Application of ionic liquid catalyst prepared by simple ion exchange method in cycloaddition reaction of epoxide and carbon dioxide: Weigh 0.024 g of the [DABCO][PF6] catalyst prepared in Example 5 and put it into a parallel reactor containing 4 mmol of styrene oxide, which is equipped with a magnetic stirrer and has a volume of 10 mL. After the reactor is carefully sealed, it is purged with CO2 gas three times to remove the residual gas in the reactor, and then filled with CO2 to maintain the reactor pressure at 1.1 MPa, and the reaction temperature is set to 110°C, stirring is turned on, and the reaction is carried out at a speed of 400 rpm for 12 h. After the reaction is completed, the reactor is cooled to below 10°C using an ice water bath, and the excess gas in the reactor is slowly released until the reactor returns to normal pressure. After the reaction is completed, a gas chromatograph is used for quantitative analysis.

[0047] It has been determined that under the above reaction conditions, the conversion rate of the cycloaddition of styrene oxide catalyzed by [DABCO][PF6] catalyst is 97.6%, and the yield of the product styrene cyclic carbonate is over 62.1%.

[0048] Application Example 9: Application of ionic liquid catalyst prepared by simple ion exchange method in cycloaddition reaction of epoxide and carbon dioxide: Weigh 0.024 g of the [TAZ][I] catalyst prepared in Example 6 and put it into a parallel reactor containing 4 mmol of styrene oxide, which is equipped with a magnetic stirrer and has a volume of 10 mL. After the reactor is carefully sealed, it is purged with CO2 gas three times to remove the residual gas in the reactor, and then filled with CO2 to maintain the reactor pressure at 1.1 MPa, and the reaction temperature is set to 110°C, stirring is turned on, and the reaction is carried out at a speed of 400 rpm for 12 h. After the reaction is completed, the reactor is cooled to below 10°C using an ice water bath, and the excess gas in the reactor is slowly released until the reactor returns to normal pressure. After the reaction is completed, a gas chromatograph is used for quantitative analysis.

[0049] It has been determined that under the above reaction conditions, the conversion rate of the cycloaddition of styrene oxide catalyzed by [TAZ][I] catalyst is 96.7%, and the yield of the product styrene cyclic carbonate is more than 57.2%.

[0050] Application Example 10: Application of ionic liquid catalyst prepared by simple ion exchange method in cycloaddition reaction of epoxide and carbon dioxide: Weigh 0.024 g of the [BIM][Cl] catalyst prepared in Example 7 and put it into a parallel reactor containing 4 mmol of styrene oxide, which is equipped with a magnetic stirrer and has a volume of 10 mL. After the reactor is carefully sealed, it is purged with CO2 gas three times to remove the residual gas in the reactor, and then filled with CO2 to maintain the reactor pressure at 1.1 MPa, and the reaction temperature is set to 110°C, stirring is turned on, and the reaction is carried out at a speed of 400 rpm for 12 h. After the reaction is completed, the reactor is cooled to below 10°C using an ice water bath, and the excess gas in the reactor is slowly released until the reactor returns to normal pressure. After the reaction is completed, a gas chromatograph is used for quantitative analysis.

[0051] It has been determined that under the above reaction conditions, the conversion rate of the cycloaddition of styrene oxide catalyzed by [BIM][Cl] catalyst is 89.6%, and the yield of the product styrene cyclic carbonate is over 58.1%.

[0052] Application Example 11 Application of ionic liquid catalyst prepared by simple ion exchange method in cycloaddition reaction of epoxide and carbon dioxide: Weigh 0.024 g of the [DABCO][Cl] catalyst prepared in Example 8 and put it into a parallel reactor containing 4 mmol of styrene oxide, which is equipped with a magnetic stirrer and has a volume of 10 mL. After the reactor is carefully sealed, it is purged with CO2 gas three times to remove the residual gas in the reactor, and then filled with CO2 to maintain the reactor pressure at 1.1 MPa, and the reaction temperature is set to 110°C, stirring is turned on, and the reaction is carried out at a speed of 400 rpm for 12 h. After the reaction is completed, the reactor is cooled to below 10°C using an ice water bath, and the excess gas in the reactor is slowly released until the reactor returns to normal pressure. After the reaction is completed, a gas chromatograph is used for quantitative analysis.

[0053] It has been determined that under the above reaction conditions, the conversion rate of the cycloaddition of styrene oxide catalyzed by [DABCO][Cl] catalyst is 95.2%, and the yield of the product styrene cyclic carbonate is over 86.7%.

[0054] The above description is only a preferred embodiment of the present invention. All equivalent changes and modifications made according to the scope of the patent application of the present invention should fall within the scope of the present invention.

Claims

1. A method for preparing an ionic liquid catalyst by a simple ion exchange method, characterized in that: The steps include: 1) Slowly add the anion donor to the cation donor and stir the reaction at room temperature; 2) The reaction solution obtained in step 1) is dehydrated and then dried to obtain the ionic liquid catalyst.

2. The method for preparing an ionic liquid catalyst by a simple ion exchange method according to claim 1, characterized in that: In step 1), the cation donor is one of biimidazole, 1,2,4-triazole and triethylenediamine.

3. The method for preparing an ionic liquid catalyst by a simple ion exchange method according to claim 1, characterized in that: The anion donor in step 1) is one of HBr, HCl, HI, HBF4, and KPF6.

4. The method for preparing an ionic liquid catalyst by a simple ion exchange method according to claim 1, characterized in that: The molar ratio of the cation donor to the anion donor used in step 1) is 1:1-6.

5. The method for preparing an ionic liquid catalyst by a simple ion exchange method according to claim 1, characterized in that: The stirring reaction time in step 1) is 12 to 24 hours.

6. Use of an ionic liquid catalyst prepared by the method of claim 1 in catalyzing a CO2 cycloaddition reaction, characterized in that: The ionic liquid catalyst is used in the cycloaddition reaction of CO2 and epoxide.

7. The use according to claim 6, characterized in that: The epoxide is styrene oxide.

8. The use according to claim 6, characterized in that: The temperature of the cycloaddition reaction is 100-120° C., the pressure is 1-1.2 MPa, and the time is 12 h.

Images