Efficient ring-opening metathesis polymerization method based on ruthenium catalyst

Abstract

The invention provides an efficient ring-opening metathesis polymerization method based on a ruthenium catalyst, belongs to the technical field of polymer synthesis, and solves the problems of low polymerization efficiency, complex process and tedious operation of the existing method. The preparation method comprises the following steps: mixing and dissolving a large steric hindrance monomer, a Grubbs catalyst and an ionic liquid in an organic solvent for reaction, and finally adding a terminator for quenching reaction to obtain a target compound. According to the invention, the ionic liquid is used as an additive for the ring-opening metathesis polymerization reaction, and the ring-opening metathesis polymerization reaction activity of the large-steric-hindrance cycloolefin monomer is remarkably improved through a multi-synergistic effect mechanism generated between the specific anion-cation structure and the monomer and the ruthenium catalyst.

Description

Technical Field

[0001] The present invention belongs to the technical field of polymer synthesis, and particularly relates to a ring-opening metathesis polymerization reaction. Background Art

[0002] Ring-opening metathesis polymerization (ROMP) has become an important method for synthesizing various polyolefin materials in recent years due to its unique reaction mechanism. Common ring-opening metathesis polymerization monomers are norbornene monomers. These monomers undergo ring-opening metathesis polymerization and subsequent hydrogenation reactions, and the synthesized polymer is called a cycloolefin polymer, which exhibits high transparency, low birefringence, low water absorption, high strength, and excellent chemical corrosion resistance. These properties make it widely used in the medical field, optical lenses, packaging fields, etc.

[0003] However, commercially available cycloolefin polymers still have some deficiencies in heat resistance. To solve this problem, researchers have turned their attention to the design and synthesis of large steric hindrance cycloolefin monomers. By introducing a rigid cyclic structure or steric hindrance groups, the thermal properties of the polymer can be significantly improved. However, while large steric hindrance groups improve the material properties, they often lead to a decrease in the ring-opening metathesis polymerization reaction activity of the monomers. This contradictory phenomenon has become a key factor restricting the further improvement of material properties. Therefore, enhancing the ROMP reaction activity of large steric hindrance monomers has important research value for expanding the application range of cycloolefin polymers in high-temperature environments. In addition, in the prior art, the ring-opening metathesis polymerization efficiency is mainly improved by the design and optimization of the catalyst structure or the introduction of acidic additives. However, these methods generally have problems such as complex processes, limited efficiency improvement, and environmental pollution. Summary of the Invention

[0004] Aiming at the technical problems of reduced ring-opening metathesis polymerization reaction activity, complex processes, and cumbersome operations of large steric hindrance monomers, the present invention proposes an efficient ring-opening metathesis polymerization method based on a ruthenium catalyst, using an ionic liquid as an additive for the ring-opening metathesis polymerization reaction, which significantly enhances the ring-opening metathesis polymerization reaction activity of large steric hindrance cycloolefin monomers.

[0005] To achieve the above object, the technical solution of the present invention is realized as follows:

[0006] An efficient ring-opening metathesis polymerization method based on a ruthenium catalyst, comprising the following steps:

[0007] Step 1: Dissolve a large steric hindrance monomer in a dried and degassed organic solvent, and transfer it to a reaction vessel. Then, add a dried and degassed solvent system containing a stoichiometric amount of Grubbs catalyst and an ionic liquid to the monomer solution. The reaction solution is continuously stirred at room temperature for a predetermined time, and then a terminator is added to quench the reaction, and additional stirring is carried out for 30 minutes to ensure complete termination of the reaction, obtaining a homogeneous polymer solution;

[0008] Step 2: Slowly drop the obtained polymer solution into the vigorously stirred precipitant to precipitate the polymer. Filter and collect the product, and dry it to finally obtain the target polymer.

[0009] Specifically, the bulky monomer in Step 1 is selected from one of the following structures:

[0010]

[0011] The ionic liquid is selected from one of the following structures, and the amount of the ionic liquid used accounts for 0.002 - 0.01 mol% of the amount of the bulky cycloolefin monomer. For example, 0.002 mol%, 0.0025 mol%, 0.0033 mol%, 0.005 mol%, 0.01 mol%.

[0012]

[0013] It should be noted that the ionic liquid of the above structure is selected according to specific selection rules. The specific selection rules are as follows: The ionic liquid does not react with the monomer, catalyst, and solvent, and there is good mutual solubility between the monomer, solvent, and ionic liquid. Finally, it is required that the ionic liquid can be completely dissolved in the precipitant to facilitate the subsequent separation and purification process.

[0014] The catalyst is selected as the second-generation Grubbs catalyst with high activity, good functional group tolerance, appropriate price, and easy removal in the subsequent process. The amount of the catalyst used is the same as that of the ionic liquid, accounting for 0.002 - 0.01 mol% of the amount of the bulky cycloolefin monomer. For example, 0.002 mol%, 0.0025 mol%, 0.0033 mol%, 0.005 mol%, 0.01 mol%.

[0015] The organic solvent is selected from at least one of tetrahydrofuran, cyclohexane, toluene, dichloromethane, chloroform, acetone, etc. The monomer concentration is 0.1 - 0.25 mmol / mL. For example, 0.1 mmol / mL, 0.15 mmol / mL, 0.2 mmol / mL, 0.25 mmol / mL.

[0016] The reaction time is 1 - 3 minutes. For example, 1 minute, 2 minutes, 3 minutes. It should be noted that to accurately evaluate the influence of the ionic liquid on the polymerization reaction, all reactions are carried out under non-complete conversion conditions.

[0017] The terminator is ethoxyethylene. Different from the traditional chain termination achieved through the intermolecular reaction between two living polymer chains, ring-opening metathesis polymerization usually uses a chemical terminator to achieve controlled termination. These terminators can react with the metal carbene species at the growing chain end, prompting the ruthenium catalyst to dissociate from the polymer chain. This terminator is efficient and fast, and only a trace amount (5 - 8 drops) needs to be added in actual operation to completely terminate the reaction.

[0018] Specifically, in step 2, the precipitant is selected from at least one of methanol, ethanol, isopropanol, etc.

[0019] The drying treatment is carried out in a vacuum drying oven at 40 °C for 24 hours to ensure the removal of residual solvents and obtain a product with constant weight.

[0020] In the present invention, the polymerization reaction operation in step 1 is carried out entirely in an inert atmosphere glove box to ensure that the reaction system is protected from the influence of oxygen and moisture.

[0021] Advantages of the present invention:

[0022] (1) In the present invention, an ionic liquid is used as an additive for the ring-opening metathesis polymerization reaction. Through the multiple synergistic mechanism generated between its unique cationic and anionic structures and the monomer and ruthenium catalyst, the ring-opening metathesis polymerization reaction activity of the large steric hindrance cycloolefin monomer is significantly improved.

[0023] (2) In the present invention, by regulating the length of the alkyl chain of the ionic liquid cation, the further optimization of the ring-opening metathesis polymerization reaction activity of the large steric hindrance cycloolefin monomer is realized. The reaction activity is positively correlated with the length of the alkyl chain of the cation, that is, it increases with the increase of the alkyl chain length.

[0024] (3) The method of the present invention has simple process operation, less additive dosage, is environmentally friendly, has low requirements for experimental equipment, and the whole process is safe and controllable. Specific embodiments

[0025] The following will clearly and completely describe the technical solutions in combination with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of them. All other embodiments obtained by those of ordinary skill in the art without creative efforts based on the embodiments of the present invention belong to the scope of protection of the present invention.

[0026] In the following examples and comparative examples, the tricyclodecene and tetracyclododecene monomers are both prepared by the Diels - Alder reaction of cyclopentadiene with cyclopentene and cyclopentadiene with norbornene.

[0027] Example 1

[0028] An efficient ring-opening metathesis polymerization method based on ruthenium catalyst, comprising the following steps: Dissolve the prepared tricyclodecene monomer in a dried and degassed tetrahydrofuran solution (monomer concentration is 0.1 mmol / mL), and place it in a 20 ml vial equipped with a magnetic stirrer. Subsequently, add a dried and degassed tetrahydrofuran solution containing Grubbs second-generation catalyst (0.01 mol% of the amount of tricyclodecene monomer) and an ionic liquid with the structure of [EMIM]PF6 (0.01 mol% of the amount of tricyclodecene monomer) to the monomer solution. After reacting for 3 minutes, add 5 - 8 drops of ethoxyethylene to terminate the reaction, and continue stirring for 30 minutes to ensure complete termination of the reaction. Finally, add the reaction mixture dropwise to vigorously stirred anhydrous methanol to precipitate the polymer. Filter and collect the product, and dry it in a vacuum drying oven at 40 °C for 24 hours.

[0029] Example 2

[0030] An efficient ring-opening metathesis polymerization method based on ruthenium catalyst, comprising the following steps: Dissolve the prepared tricyclodecene monomer in a dried and degassed tetrahydrofuran solution (monomer concentration is 0.1 mmol / mL), and place it in a 20 ml vial equipped with a magnetic stirrer. Subsequently, add a dried and degassed tetrahydrofuran solution containing Grubbs second-generation catalyst (0.01 mol% of the amount of tricyclodecene monomer) and an ionic liquid with the structure of [BMIM]PF6 (0.01 mol% of the amount of tricyclodecene monomer) to the monomer solution. After reacting for 3 minutes, add 5 - 8 drops of ethoxyethylene to terminate the reaction, and continue stirring for 30 minutes to ensure complete termination of the reaction. Finally, add the reaction mixture dropwise to vigorously stirred anhydrous methanol to precipitate the polymer. Filter and collect the product, and dry it in a vacuum drying oven at 40 °C for 24 hours.

[0031] Example 3

[0032] An efficient ring-opening metathesis polymerization method based on ruthenium catalyst, comprising the following steps: Dissolve the prepared tricyclodecene monomer in a dried and degassed tetrahydrofuran solution (monomer concentration is 0.1 mmol / mL), and place it in a 20 ml vial equipped with a magnetic stirrer. Subsequently, add a dried and degassed tetrahydrofuran solution containing Grubbs second-generation catalyst (0.01 mol% of the amount of tricyclodecene monomer) and an ionic liquid with the structure of [HMIM]PF6 (0.01 mol% of the amount of tricyclodecene monomer) to the monomer solution. After reacting for 3 minutes, add 5 - 8 drops of ethoxyethylene to terminate the reaction, and continue stirring for 30 minutes to ensure complete termination of the reaction. Finally, add the reaction mixture dropwise to vigorously stirred anhydrous methanol to precipitate the polymer. Filter and collect the product, and dry it in a vacuum drying oven at 40 °C for 24 hours.

[0033] Example 4

[0034] An efficient ring-opening metathesis polymerization method based on ruthenium catalyst, comprising the following steps: Dissolve the prepared tricyclodecene monomer in a dry and degassed tetrahydrofuran solution (monomer concentration is 0.1 mmol / mL), and place it in a 20 ml vial equipped with a magnetic stirrer. Subsequently, add a dry and degassed tetrahydrofuran solution containing Grubbs second-generation catalyst (0.01 mol% of the amount of tricyclodecene monomer) and an ionic liquid with the structure of [OMIM]PF6 (0.01 mol% of the amount of tricyclodecene monomer) to the monomer solution. After reacting for 3 minutes, add 5 - 8 drops of ethoxyethylene to terminate the reaction, and continue stirring for 30 minutes to ensure complete termination of the reaction. Finally, add the reaction mixture dropwise to vigorously stirred anhydrous methanol to precipitate the polymer. Filter and collect the product, and dry it in a vacuum drying oven at 40 °C for 24 hours.

[0035] Example 5

[0036] An efficient ring-opening metathesis polymerization method based on ruthenium catalyst, comprising the following steps: Dissolve the prepared tricyclodecene monomer in a dry and degassed tetrahydrofuran solution (monomer concentration is 0.1 mmol / mL), and place it in a 20 ml vial equipped with a magnetic stirrer. Subsequently, add a dry and degassed tetrahydrofuran solution containing Grubbs second-generation catalyst (0.01 mol% of the amount of tricyclodecene monomer) and an ionic liquid with the structure of [DMIM]PF6 (0.01 mol% of the amount of tricyclodecene monomer) to the monomer solution. After reacting for 3 minutes, add 5 - 8 drops of ethoxyethylene to terminate the reaction, and continue stirring for 30 minutes to ensure complete termination of the reaction. Finally, add the reaction mixture dropwise to vigorously stirred anhydrous methanol to precipitate the polymer. Filter and collect the product, and dry it in a vacuum drying oven at 40 °C for 24 hours.

[0037] Example 6

[0038] A highly efficient ring-opening metathesis polymerization method based on ruthenium catalyst, comprising the following steps: Dissolve the prepared tricyclodecene monomer in a dried and degassed cyclohexane solution (monomer concentration is 0.15 mmol / mL), and place it in a 20 ml vial equipped with a magnetic stirrer. Subsequently, add a dried and degassed cyclohexane solution containing Grubbs second-generation catalyst (0.01 mol% of the amount of tricyclodecene monomer) and an ionic liquid with the structure of [EMIM]PF6 (0.01 mol% of the amount of tricyclodecene monomer) to the monomer solution. After reacting for 3 minutes, add 5 - 8 drops of ethoxyethylene to terminate the reaction, and continue stirring for 30 minutes to ensure complete termination of the reaction. Finally, add the reaction mixture dropwise to vigorously stirred anhydrous methanol to precipitate the polymer. Filter and collect the product, and dry it in a vacuum drying oven at 40 °C for 24 hours.

[0039] Example 7

[0040] A highly efficient ring-opening metathesis polymerization method based on ruthenium catalyst, comprising the following steps: Dissolve the prepared tricyclodecene monomer in a dried and degassed toluene solution (monomer concentration is 0.2 mmol / mL), and place it in a 20 ml vial equipped with a magnetic stirrer. Subsequently, add a dried and degassed toluene solution containing Grubbs second-generation catalyst (0.01 mol% of the amount of tricyclodecene monomer) and an ionic liquid with the structure of [EMIM]PF6 (0.01 mol% of the amount of tricyclodecene monomer) to the monomer solution. After reacting for 3 minutes, add 5 - 8 drops of ethoxyethylene to terminate the reaction, and continue stirring for 30 minutes to ensure complete termination of the reaction. Finally, add the reaction mixture dropwise to vigorously stirred anhydrous methanol to precipitate the polymer. Filter and collect the product, and dry it in a vacuum drying oven at 40 °C for 24 hours.

[0041] Example 8

[0042] A highly efficient ring-opening metathesis polymerization method based on ruthenium catalyst, comprising the following steps: Dissolve the prepared tricyclodecene monomer in a dried and degassed dichloromethane solution (monomer concentration is 0.25 mmol / mL), and place it in a 20 ml vial equipped with a magnetic stirrer. Subsequently, add a dried and degassed dichloromethane solution containing Grubbs second-generation catalyst (0.01 mol% of the amount of tricyclodecene monomer) and an ionic liquid with the structure of [EMIM]PF6 (0.01 mol% of the amount of tricyclodecene monomer) to the monomer solution. After reacting for 3 minutes, add 5 - 8 drops of ethoxyethylene to terminate the reaction, and continue stirring for 30 minutes to ensure complete termination of the reaction. Finally, add the reaction mixture dropwise to vigorously stirred anhydrous methanol to precipitate the polymer. Filter and collect the product, and dry it in a vacuum drying oven at 40 °C for 24 hours.

[0043] Example 9

[0044] An efficient ring-opening metathesis polymerization method based on ruthenium catalyst, comprising the following steps: Dissolve the prepared tricyclodecene monomer in a dried and degassed tetrahydrofuran solution (monomer concentration is 0.1 mmol / mL), and place it in a 20 ml vial equipped with a magnetic stirrer. Subsequently, add a dried and degassed tetrahydrofuran solution containing Grubbs second-generation catalyst (0.01 mol% of the amount of tricyclodecene monomer) and an ionic liquid with the structure of [BMIM]PF6 (0.01 mol% of the amount of tricyclodecene monomer) to the monomer solution. After reacting for 1 minute, add 5 - 8 drops of ethoxyethylene to terminate the reaction, and continue stirring for 30 minutes to ensure complete termination of the reaction. Finally, add the reaction mixture dropwise to vigorously stirred ethanol to precipitate the polymer. Filter and collect the product, and dry it in a vacuum drying oven at 40°C for 24 hours.

[0045] Example 10

[0046] An efficient ring-opening metathesis polymerization method based on ruthenium catalyst, comprising the following steps: Dissolve the prepared tricyclodecene monomer in a dried and degassed tetrahydrofuran solution (monomer concentration is 0.1 mmol / mL), and place it in a 20 ml vial equipped with a magnetic stirrer. Subsequently, add a dried and degassed tetrahydrofuran solution containing Grubbs second-generation catalyst (0.01 mol% of the amount of tricyclodecene monomer) and an ionic liquid with the structure of [BMIM]PF6 (0.01 mol% of the amount of tricyclodecene monomer) to the monomer solution. After reacting for 2 minutes, add 5 - 8 drops of ethoxyethylene to terminate the reaction, and continue stirring for 30 minutes to ensure complete termination of the reaction. Finally, add the reaction mixture dropwise to vigorously stirred isopropanol to precipitate the polymer. Filter and collect the product, and dry it in a vacuum drying oven at 40°C for 24 hours.

[0047] Example 11

[0048] A highly efficient ring-opening metathesis polymerization method based on ruthenium catalyst, comprising the following steps: Dissolve the prepared tricyclodecene monomer in a dried and degassed acetone solution (monomer concentration is 0.1 mmol / mL), and place it in a 20 ml vial equipped with a magnetic stirrer. Subsequently, add a dried and degassed acetone solution containing Grubbs second-generation catalyst (accounting for 0.002 mol% of the amount of tricyclodecene monomer) and an ionic liquid with the structure of [HMIM]PF6 (accounting for 0.002 mol% of the amount of tricyclodecene monomer) to the monomer solution. After reacting for 3 minutes, add 5 - 8 drops of ethoxyethylene to terminate the reaction, and continue stirring for 30 minutes to ensure complete termination of the reaction. Finally, add the reaction mixture dropwise to vigorously stirred anhydrous methanol to precipitate the polymer. Filter and collect the product, and dry it in a vacuum drying oven at 40 °C for 24 hours.

[0049] Example 12

[0050] A highly efficient ring-opening metathesis polymerization method based on ruthenium catalyst, comprising the following steps: Dissolve the prepared tricyclodecene monomer in a dried and degassed chloroform solution (monomer concentration is 0.1 mmol / mL), and place it in a 20 ml vial equipped with a magnetic stirrer. Subsequently, add a dried and degassed chloroform solution containing Grubbs second-generation catalyst (accounting for 0.0025 mol% of the amount of tricyclodecene monomer) and an ionic liquid with the structure of [HMIM]PF6 (accounting for 0.0025 mol% of the amount of tricyclodecene monomer) to the monomer solution. After reacting for 3 minutes, add 5 - 8 drops of ethoxyethylene to terminate the reaction, and continue stirring for 30 minutes to ensure complete termination of the reaction. Finally, add the reaction mixture dropwise to vigorously stirred anhydrous methanol to precipitate the polymer. Filter and collect the product, and dry it in a vacuum drying oven at 40 °C for 24 hours.

[0051] Example 13

[0052] A highly efficient ring-opening metathesis polymerization method based on ruthenium catalyst, comprising the following steps: Dissolve the prepared tricyclodecene monomer in a dried and degassed acetone solution (monomer concentration is 0.1 mmol / mL), and place it in a 20 ml vial equipped with a magnetic stirrer. Subsequently, add a dried and degassed acetone solution containing Grubbs second-generation catalyst (accounting for 0.0033 mol% of the amount of tricyclodecene monomer) and an ionic liquid with the structure of [HMIM]PF6 (accounting for 0.0033 mol% of the amount of tricyclodecene monomer) to the monomer solution. After reacting for 3 minutes, add 5 - 8 drops of ethoxyethylene to terminate the reaction, and continue stirring for 30 minutes to ensure complete termination of the reaction. Finally, add the reaction mixture dropwise to vigorously stirred anhydrous methanol to precipitate the polymer. Filter and collect the product, and dry it in a vacuum drying oven at 40 °C for 24 hours.

[0053] Example 14

[0054] A highly efficient ring-opening metathesis polymerization method based on ruthenium catalyst, comprising the following steps: Dissolve the prepared tricyclodecene monomer in a dried and degassed acetone solution (monomer concentration is 0.1 mmol / mL), and place it in a 20 ml vial equipped with a magnetic stirrer. Subsequently, add a dried and degassed acetone solution containing Grubbs second-generation catalyst (accounting for 0.005 mol% of the tricyclodecene monomer dosage) and an ionic liquid with the structure of [HMIM]PF6 (accounting for 0.005 mol% of the tricyclodecene monomer dosage) to the monomer solution. After reacting for 3 minutes, add 5 - 8 drops of ethoxyethylene to terminate the reaction, and continue stirring for 30 minutes to ensure complete termination of the reaction. Finally, add the reaction mixture dropwise to vigorously stirred anhydrous methanol to precipitate the polymer. Filter and collect the product, and dry it in a vacuum drying oven at 40 °C for 24 hours.

[0055] Example 15

[0056] A highly efficient ring-opening metathesis polymerization method based on ruthenium catalyst, comprising the following steps: Dissolve the prepared tetracyclododecene monomer in a dried and degassed tetrahydrofuran solution (monomer concentration is 0.1 mmol / mL), and place it in a 20 ml vial equipped with a magnetic stirrer. Subsequently, add a dried and degassed tetrahydrofuran solution containing Grubbs second-generation catalyst (accounting for 0.01 mol% of the tetracyclododecene monomer dosage) and an ionic liquid with the structure of [EMIM]PF6 (accounting for 0.01 mol% of the tetracyclododecene monomer dosage) to the monomer solution. After reacting for 1 minute, add 5 - 8 drops of ethoxyethylene to terminate the reaction, and continue stirring for 30 minutes to ensure complete termination of the reaction. Finally, add the reaction mixture dropwise to vigorously stirred anhydrous methanol to precipitate the polymer. Filter and collect the product, and dry it in a vacuum drying oven at 40 °C for 24 hours.

[0057] Example 16

[0058] A highly efficient ring-opening metathesis polymerization method based on ruthenium catalyst, comprising the following steps: Dissolve the prepared cyclododecatriene monomer in a dry and degassed tetrahydrofuran solution (monomer concentration is 0.1 mmol / mL), and place it in a 20 ml vial equipped with a magnetic stirrer. Subsequently, add a dry and degassed tetrahydrofuran solution containing Grubbs second-generation catalyst (0.01 mol% of the amount of cyclododecatriene monomer) and an ionic liquid with the structure of [BMIM]PF6 (0.01 mol% of the amount of cyclododecatriene monomer) to the monomer solution. After reacting for 1 minute, add 5 - 8 drops of ethoxyethylene to terminate the reaction, and continue stirring for 30 minutes to ensure complete termination of the reaction. Finally, add the reaction mixture dropwise to vigorously stirred anhydrous methanol to precipitate the polymer. Filter and collect the product, and dry it in a vacuum drying oven at 40°C for 24 hours.

[0059] Example 17

[0060] A highly efficient ring-opening metathesis polymerization method based on ruthenium catalyst, comprising the following steps: Dissolve the prepared cyclododecatriene monomer in a dry and degassed tetrahydrofuran solution (monomer concentration is 0.1 mmol / mL), and place it in a 20 ml vial equipped with a magnetic stirrer. Subsequently, add a dry and degassed tetrahydrofuran solution containing Grubbs second-generation catalyst (0.01 mol% of the amount of cyclododecatriene monomer) and an ionic liquid with the structure of [HMIM]PF6 (0.01 mol% of the amount of cyclododecatriene monomer) to the monomer solution. After reacting for 1 minute, add 5 - 8 drops of ethoxyethylene to terminate the reaction, and continue stirring for 30 minutes to ensure complete termination of the reaction. Finally, add the reaction mixture dropwise to vigorously stirred anhydrous methanol to precipitate the polymer. Filter and collect the product, and dry it in a vacuum drying oven at 40°C for 24 hours.

[0061] Example 18

[0062] A highly efficient ring-opening metathesis polymerization method based on ruthenium catalyst, comprising the following steps: Dissolve the prepared cyclododecatriene monomer in a dry and degassed tetrahydrofuran solution (monomer concentration is 0.1 mmol / mL), and place it in a 20 ml vial equipped with a magnetic stirrer. Subsequently, add a dry and degassed tetrahydrofuran solution containing Grubbs second-generation catalyst (0.01 mol% of the amount of cyclododecatriene monomer) and an ionic liquid with the structure of [OMIM]PF6 (0.01 mol% of the amount of cyclododecatriene monomer) to the monomer solution. After reacting for 1 minute, add 5 - 8 drops of ethoxyethylene to terminate the reaction, and continue stirring for 30 minutes to ensure complete termination of the reaction. Finally, add the reaction mixture dropwise to vigorously stirred anhydrous methanol to precipitate the polymer. Filter and collect the product, and dry it in a vacuum drying oven at 40°C for 24 hours.

[0063] Example 19

[0064] An efficient ring-opening metathesis polymerization method based on ruthenium catalyst, comprising the following steps: Dissolve the prepared cyclododecene monomer in a dry and degassed tetrahydrofuran solution (monomer concentration is 0.1 mmol / mL), and place it in a 20 ml vial equipped with a magnetic stirrer. Subsequently, add a dry and degassed tetrahydrofuran solution containing Grubbs second-generation catalyst (0.01 mol% of the amount of cyclododecene monomer) and an ionic liquid with the structure of [DMIM]PF6 (0.01 mol% of the amount of cyclododecene monomer) to the monomer solution. After reacting for 1 minute, add 5 - 8 drops of ethoxyethylene to terminate the reaction, and continue stirring for 30 minutes to ensure complete termination of the reaction. Finally, add the reaction mixture dropwise to vigorously stirred anhydrous methanol to precipitate the polymer. Filter and collect the product, and dry it in a vacuum drying oven at 40 °C for 24 hours.

[0065] Comparative Example 1

[0066] An efficient ring-opening metathesis polymerization method based on ruthenium catalyst, comprising the following steps: Dissolve the prepared tricyclodecene monomer in a dry and degassed tetrahydrofuran solution (monomer concentration is 0.1 mmol / mL), and place it in a 20 ml vial equipped with a magnetic stirrer. Subsequently, add a dry and degassed tetrahydrofuran solution containing Grubbs second-generation catalyst (0.01 mol% of the amount of tricyclodecene monomer) to the monomer solution. After reacting for 3 minutes, add 5 - 8 drops of ethoxyethylene to terminate the reaction, and continue stirring for 30 minutes to ensure complete termination of the reaction. Finally, add the reaction mixture dropwise to vigorously stirred anhydrous methanol to precipitate the polymer. Filter and collect the product, and dry it in a vacuum drying oven at 40 °C for 24 hours.

[0067] Comparative Example 2

[0068] An efficient ring-opening metathesis polymerization method based on ruthenium catalyst, comprising the following steps: Dissolve the prepared cyclododecene monomer in a dry and degassed tetrahydrofuran solution (monomer concentration is 0.1 mmol / mL), and place it in a 20 ml vial equipped with a magnetic stirrer. Subsequently, add a dry and degassed tetrahydrofuran solution containing Grubbs second-generation catalyst (0.01 mol% of the amount of cyclododecene monomer) to the monomer solution. After reacting for 1 minute, add 5 - 8 drops of ethoxyethylene to terminate the reaction, and continue stirring for 30 minutes to ensure complete termination of the reaction. Finally, add the reaction mixture dropwise to vigorously stirred anhydrous methanol to precipitate the polymer. Filter and collect the product, and dry it in a vacuum drying oven at 40 °C for 24 hours.

[0069] A series of tests were conducted on the target products obtained from the above examples and comparative examples, and the test results are listed in Table 1. The specific tests are as follows:

[0070] (1) In the present invention, the yield is the mass percentage of the weight of the target product in the weight of the added bulky cycloolefin monomer.

[0071] (2) Gel permeation chromatography was used to test the molecular weight (M n ) and molecular weight distribution (PDI) of the synthesized polymer; the experiment was carried out on a Shimadzu LC-20ADXR type gel permeation chromatograph. In the experiment, tetrahydrofuran was used as the mobile phase, the flow rate was 1 ml / min, the temperature was 40 °C, and the analysis results were corrected with a polystyrene standard SM-105.

[0072] (3) Differential scanning calorimetry was used to test the glass transition temperature (T g ) of the synthesized polymer; the experiment was carried out on a Mettler DSC1 type differential scanning calorimeter under a nitrogen atmosphere. During the experiment, the sample was heated and cooled at a rate of 10 °C / min, the temperature range was set from 25 °C to 200 °C, and the T g value was determined during the second heating process and defined as the midpoint of the heat capacity change.

[0073] (4) Thermogravimetric analyzer was used to test the thermal decomposition temperature (T d,10％ , that is, the temperature at which the weight loss is 10%) of the synthesized polymer; the experiment was carried out on a Shimadzu DTG-60H type thermogravimetric analyzer under a nitrogen atmosphere. The temperature scanning range was set from 25 °C to 600 °C, and the heating rate was 10 °C / min.

[0074] Table 1 Polymerization results of bulky cycloolefin monomers

[0075] Group Ionic liquid Yield (%) <![CDATA[Mn×10 -4 > PDI <![CDATA[T g (℃)]]> <![CDATA[T d,10％ (℃)]]> Example 1 <![CDATA[[EMIM]PF6]]> 50.10 72.9 2.2 154.62 417 Example 2 <![CDATA[[BMIM]PF6]]> 54.23 71.9 2.2 155.75 413 Example 3 <![CDATA[[HMIM]PF6]]> 56.17 74.0 2.0 157.69 406 Example 4 <![CDATA[[OMIM]PF6]]> 59.70 61.4 2.3 158.14 414 Example 5 <![CDATA[[DMIM]PF6]]> 63.63 61.8 2.3 158.22 411 Example 6 <![CDATA[[EMIM]PF6]]> 57.25 69.7 2.1 156.42 415 Example 7 <![CDATA[[EMIM]PF6]]> 70.94 64.9 2.0 157.46 408 Example 8 <![CDATA[[EMIM]PF6]]> 83.68 66.5 2.2 157.78 411 Example 9 <![CDATA[[BMIM]PF6]]> 34.48 67.9 2.3 155.10 405 Example 10 <![CDATA[[BMIM]PF6]]> 44.23 68.1 2.3 156.17 407 Example 11 <![CDATA[[HMIM]PF6]]> 12.60 66.9 2.0 155.92 415 Example 12 <![CDATA[[HMIM]PF6]]> 25.02 70.1 2.0 157.17 409 Example 13 <![CDATA[[HMIM]PF6]]> 32.06 68.2 2.3 156.36 400 Example 14 <![CDATA[[HMIM]PF6]]> 43.17 63.8 2.1 156.25 413 Example 15 <![CDATA[[EMIM]PF6]]> 52.67 61.0 1.6 98.89 402 Example 16 <![CDATA[[BMIM]PF6]]> 53.08 69.1 1.7 100.35 402 Example 17 <![CDATA[[HMIM]PF6]]> 55.79 68.9 1.7 101.09 399 Example 18 <![CDATA[[OMIM]PF6]]> 60.04 67.2 1.8 102.14 403 Example 19 <![CDATA[[DMIM]PF6]]> 63.88 73.6 1.9 103.24 394 Comparative Example 1 None 47.76 51.0 2.1 153.36 416 Comparative Example 2 None 50.00 66.5 1.7 90.97 400

[0076] It can be seen from Examples 1-5 and Comparative Example 1 that the introduction of ionic liquid can significantly improve the ring-opening metathesis polymerization activity of tricyclodecene monomers, and this activity shows an obvious positive correlation with the carbon chain length of the ionic liquid cation. When no ionic liquid was added (Comparative Example 1), the reaction yield was 47.76%; when [EMIM]PF6 was used (Example 1), the reaction yield increased to 50.10%. After using [BMIM]PF6 (Example 2), the reaction yield was further optimized to 54.23%, and the best reaction performance occurred when [DMIM]PF6 was used (Example 5), and the reaction yield increased significantly to 63.63%.

[0077] Meanwhile, it can also be seen from Table 1 that the introduction of ionic liquids significantly improves the thermal properties of the resulting polymers, and this improvement effect is closely related to the carbon chain length of the ionic liquid cations, manifested as a regular increase in the T g value. Specifically, the T g value of the polymer increases from 153.36 °C without adding ionic liquids to 158.22 °C, and the highest value appears in Example 5 using [DMIM]PF6 as an additive.

[0078] In addition, from Examples 1-3 and Examples 6-14, it can be seen that changing the monomer concentration, reaction time, and the dosages of ionic liquids and catalysts will all cause changes in the yield, specifically showing a positive correlation between the three and the yield.

[0079] Furthermore, from the data of Examples 15-19 and Comparative Example 2, it can be seen that a similar phenomenon also occurs for the tetracyclododecene monomer. When no ionic liquid is added (Comparative Example 2), the reaction yield is 50.00%; when [EMIM]PF6 is used (Example 15), the reaction yield increases to 52.67%. After using [BMIM]PF6 (Example 16), the reaction yield is further optimized to 53.08%, and the best reaction performance appears when using [DMIM]PF6 (Example 19), and the reaction yield significantly increases to 63.88%. In addition, the T g value of the resulting polymer also linearly increases from 90.97 °C to 103.24 °C with the increase in the carbon chain length of the ionic liquid cations. These results indicate that the introduction of ionic liquids can effectively improve the ring-opening metathesis polymerization reaction activity of large steric hindrance cycloolefin monomers, and this promoting effect is positively correlated with the alkyl chain length of the ionic liquid cations, that is, the reaction activity increases with the increase in the alkyl chain length.

[0080] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims

1. A highly efficient ring-opening metathesis polymerization method based on ruthenium catalysts, characterized in that, It includes the following steps: Mix a bulky monomer, a Grubbs catalyst, and an ionic liquid and dissolve them in an organic solvent for reaction, and finally add a terminator to quench the reaction to obtain the target compound.

2. The high-efficiency ring-opening metathesis polymerization method based on a ruthenium catalyst according to claim 1, wherein The bulky monomer is selected from one of the following structures:

3. The high-efficiency ring-opening metathesis polymerization method based on ruthenium catalyst according to claim 1, wherein The ionic liquid is selected from one of the following structures:

4. The high-efficiency ring-opening metathesis polymerization method based on a ruthenium catalyst according to claim 3, characterized in that, The dosage of the ionic liquid accounts for 0.002 - 0.01 mol% of the dosage of the bulky cycloolefin monomer.

5. The high-efficiency ring-opening metathesis polymerization method based on a ruthenium catalyst according to claim 1, characterized in that The Grubbs catalyst is the second-generation Grubbs catalyst.

6. The high-efficiency ring-opening metathesis polymerization method based on a ruthenium catalyst according to claim 5, wherein The Grubbs catalyst accounts for 0.002 - 0.01 mol% of the dosage of the bulky cycloolefin monomer.

7. The high-efficiency ring-opening metathesis polymerization method based on a ruthenium catalyst according to claim 1, wherein The solvent is at least one of tetrahydrofuran, cyclohexane, toluene, dichloromethane, chloroform, acetone, etc.

8. The high-efficiency ring-opening metathesis polymerization method based on a ruthenium catalyst according to claim 7, characterized in that The concentration of the bulky monomer in the organic solvent is 0.1 - 0.25 mmol / mL.

9. The high-efficiency ring-opening metathesis polymerization method based on ruthenium catalyst according to claim 1, characterized in that, The temperature of the reaction is room temperature and the time is 1 - 3 minutes.

10. The high-efficiency ring-opening metathesis polymerization method based on a ruthenium catalyst according to any one of claims 1-9, characterized in that, The terminator is ethoxyethylene.

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