Catalyst for COP (cycloolefin polymer) polymerization as well as preparation method and application of catalyst

Abstract

The invention provides a catalyst for COP (cycloolefin polymer) polymerization as well as a preparation method and application of the catalyst. The catalyst consists of an active component and an auxiliary agent. The active component is a homogeneous complex formed by divalent or trivalent ruthenium salt and a specific phosphine ligand, the auxiliary agent is an alkylaluminoxane compound, and the addition amount of the auxiliary agent is 3-8% of the mass of the active component. The preparation method of the catalyst comprises the steps of ruthenium precursor solution preparation, ligand complexation reaction, assistant introduction, crystallization and purification and the like, and is realized by accurately controlling reaction conditions and parameters. In application, the catalyst can act with a cycloolefin monomer under a ring-opening metathesis polymerization reaction condition, a new way is provided for synthesis of a cycloolefin polymer COP, the problems of low catalytic efficiency and many side reactions in COP polymerization are solved, and research and development of the catalyst have important significance on optimization of a COP polymerization process and improvement of polymer performance.

Description

Technical Field

[0001] This invention relates to the field of cyclic olefin polymer (COP) polymerization, and particularly to a catalyst for the preparation and application of the catalyst. Background Technology

[0002] Cyclic olefin polymers (COPs) exhibit great application potential in numerous fields such as optical materials, electronic packaging, and medical devices due to their excellent optical transparency, low hygroscopicity, high glass transition temperature, and superior mechanical properties. As various industries continuously raise the performance requirements of COPs, research on catalysts and catalytic methods in their polymerization process is becoming increasingly crucial. COPs, a type of cyclic olefin polymer, are produced using ring-opening metathesis polymerization, and the polymerization catalyst has a vital influence on this process.

[0003] Traditional catalysts have low activity, resulting in slow polymerization rates and high sensitivity to water and oxygen. This not only leads to long production cycles and low efficiency but also severely limits the control of process conditions. For example, some early transition metal catalysts often require several hours or even tens of hours to reach a certain conversion rate when catalyzing the polymerization of cyclic olefin monomers, making it difficult to meet the needs of large-scale industrial production. While novel catalysts have significantly improved stability and efficiency, their selectivity still needs improvement. During polymerization, it is difficult to precisely control the reaction mode of cyclic olefin monomers, easily generating a large number of byproducts that affect the purity and performance of the polymer. Taking the preparation of COP with a specific structure through the mixed polymerization of multiple cyclic olefin monomers as an example, due to poor catalyst selectivity, it is impossible to effectively guide the monomers to connect in a predetermined order and manner, resulting in an irregular polymer microstructure and a wide molecular weight distribution. Consequently, the product fails to meet the standards for high-end applications in terms of optical and mechanical properties. In summary, developing a highly active and selective catalyst for cyclic olefin polymers (COP) and its preparation method is of significant practical importance, and this is the key problem that this invention aims to solve. Summary of the Invention

[0004] Therefore, this invention proposes a catalyst for the polymerization of cyclic olefin polymers (COP), its preparation method, and its application, thereby solving the aforementioned problems.

[0005] The technical solution of the present invention is achieved as follows: a catalyst for cyclic olefin polymers (COP): the catalyst comprises an active component and an auxiliary agent, wherein: The active component is a homogeneous complex formed by a ruthenium salt and a phosphine ligand, wherein the ruthenium salt is selected from divalent or trivalent ruthenium; The auxiliary agent is an alkylaluminoxane compound, and its addition amount is 3%-8% of the mass of the active component.

[0006] Furthermore, the phosphine ligand is selected from triphenylphosphine (PPh3), tricyclohexylphosphine (PCy3), 1,2-bis(diphenylphosphine)ethane (dppe) or tri-tert-butylphosphine (PtBu3).

[0007] Furthermore, the ruthenium salt is ruthenium trichloride (RuCl3・3H2O), ruthenium acetate (Ru(OAc)3), or ruthenium dichloride ([Ru(p-cymene)Cl2]).

[0008] Furthermore, in the complex, the molar ratio of phosphine ligand to ruthenium salt is (2-4):1.

[0009] Furthermore, the alkylaluminoxane compound is selected from methylaluminoxane (MAO) or ethylaluminoxane (EAO).

[0010] Furthermore, a method for preparing a catalyst for cyclic olefin polymers (COP) includes the following steps: S1. Preparation of ruthenium precursor solution: Under argon protection, ruthenium salt is dissolved in an anhydrous organic solvent to form a solution with a concentration of 0.05-0.2 mol / L; S2, Ligand complexation reaction: Add the phosphine ligand to the ruthenium salt solution in step S1 and stir the reaction at 25-45℃ for 3-8 hours; S3, Additive introduction: Add alkylaluminoxane compound to the complexed solution of step S2, stir for 0.5-2 hours to form a homogeneous catalyst solution; S4. Crystallization and purification: After the reaction is completed, the solvent is removed by vacuum distillation, and the mixture of n-hexane and diethyl ether is added for recrystallization. After filtration, the mixture is dried under vacuum at 40-60℃ to obtain the target catalyst.

[0011] Furthermore, the organic solvent in step S1 is one or more of tetrahydrofuran, dichloromethane, or toluene.

[0012] Furthermore, in step S4, the volume ratio of n-hexane to diethyl ether is 1:(1-3).

[0013] Furthermore, the application of the catalyst for the COP polymerization of cyclic olefin polymers is characterized in that the application includes reacting the catalyst with cyclic olefin monomers under ring-opening metathesis polymerization conditions.

[0014] Compared with the prior art, the beneficial effects of the present invention are: Regarding the catalyst composition, the active component is a homogeneous complex formed by ruthenium salt and specific phosphine ligands. The rational selection of the valence state of the ruthenium salt and the type of phosphine ligand endows the catalyst with high activity and selectivity, enabling precise control of the cycloolefin polymerization process. By optimizing the catalyst formulation and reaction conditions, the catalytic activity is effectively improved, and the reaction time is significantly shortened to less than 4 hours. At the same time, the addition of alkylaluminoxane compounds as auxiliary agents is controlled at 5%-15% of the mass of the active component, effectively enhancing the stability and catalytic efficiency of the catalyst. The synergistic effect of these two factors not only significantly improves the polymerization rate and product quality but also controls the by-product content to <0.3%.

[0015] In terms of preparation methods, the multi-step process design and strict control of parameters at each stage, such as the selection of specific temperatures, times, and solvents, ensure the controllability and repeatability of the catalyst preparation process, which is conducive to large-scale industrial production. From an application perspective, this catalyst can prepare high-performance cyclic olefin polymers through ring-opening metathesis polymerization in the COP polymerization of cyclic olefin polymers. These polymers have broad application prospects in fields such as optics, electronics, and medical devices, providing strong technical support for the development of related industries and significantly improving product competitiveness and economic benefits. Detailed Implementation

[0016] To better understand the technical content of this invention, specific embodiments are provided below to further illustrate the invention.

[0017] Unless otherwise specified, the experimental methods used in the embodiments of this invention are all conventional methods.

[0018] Unless otherwise specified, all materials and reagents used in the embodiments of this invention are commercially available.

[0019] Example 1 Catalyst preparation (1) Preparation of ruthenium precursor solution: Under argon protection, 0.01 mol of ruthenium trichloride (RuCl3・3H2O) was dissolved in 100 mL of tetrahydrofuran to form a solution with a concentration of 0.1 mol / L. (2) Ligand complexation reaction: 0.03 mol of triphenylphosphine (PPh3) was added to the above ruthenium salt solution and stirred at 30°C for 5 hours. (3) Introduction of additives: Add 5% by mass of methylaluminoxane (MAO) to the complexation solution and stir for 1 hour to form a homogeneous catalyst solution.

[0020] (4) Crystallization and purification: After the reaction was completed, the solvent was removed by vacuum distillation, and a mixed solvent of hexane-diethyl ether (volume ratio 1:2) was added for recrystallization. After filtration, the solution was dried under vacuum at 50°C to obtain the target catalyst Cat-1.

[0021] Example 2 Catalyst preparation (1) Preparation of ruthenium precursor solution: Under argon protection, 0.015 mol of ruthenium acetate (Ru(OAc)3) was dissolved in 150 mL of dichloromethane to form a solution with a concentration of 0.1 mol / L. (2) Ligand complexation reaction: 0.045 mol of tricyclohexylphosphine (PCy3) was added to the ruthenium salt solution and stirred at 40°C for 6 hours. (3) Introduction of additives: Add 3% by mass of ethylaluminoxane (EAO) to the complexation solution and stir for 1.5 hours to form a homogeneous catalyst solution. (4) Crystallization and purification: After the reaction was completed, the solvent was removed by vacuum distillation, and a mixed solvent of n-hexane-diethyl ether (volume ratio 1:1.5) was added for recrystallization. After filtration, the solution was dried under vacuum at 55°C to obtain the target catalyst Cat-2.

[0022] Example 3 Catalyst preparation (1) Preparation of ruthenium precursor solution: Under argon protection, 0.008 mol of bis(p-methylisopropylbenzene) ruthenium dichloride ([Ru(p-cymene)Cl2]2) was dissolved in 80 mL of toluene to form a solution with a concentration of 0.1 mol / L. (2) Ligand complexation reaction: 0.024 mol of 1,2-bis(diphenylphosphine)ethane (dppe) was added to a ruthenium salt solution and stirred at 25°C for 8 hours. (3) Introduction of additives: Add methylaluminoxane (MAO) at a mass of 8% of the active component to the complexation solution and stir for 0.5 hours to form a homogeneous catalyst solution. (4) Crystallization and purification: After the reaction was completed, the solvent was removed by vacuum distillation, and a mixed solvent of n-hexane-diethyl ether (volume ratio 1:2.5) was added for recrystallization. After filtration, the solution was dried under vacuum at 45°C to obtain the target catalyst Cat-3.

[0023] Comparative Example 1 Catalyst preparation (1) Preparation of ruthenium precursor solution: Under argon protection, 0.01 mol of ruthenium trichloride (RuCl3・3H2O) was dissolved in 100 mL of tetrahydrofuran to form a solution with a concentration of 0.1 mol / L. (2) Ligand complexation reaction: 0.03 mol of 1,2-bis(diphenylphosphine)ethane (dppe) was added to the above ruthenium salt solution and stirred at 30°C for 5 hours. (3) Crystallization and purification: After the reaction is completed, the solvent is removed by vacuum distillation, and a mixed solvent of n-hexane-diethyl ether (volume ratio 1:2) is added for recrystallization. After filtration, the mixture is dried under vacuum at 50°C to obtain the catalyst Cat-C1 without the auxiliary agent. Comparative Example 2 Catalyst preparation (1) Preparation of ruthenium precursor solution: Under argon protection, 0.015 mol of ruthenium acetate (Ru(OAc)3) was dissolved in 150 mL of dichloromethane to form a solution with a concentration of 0.1 mol / L. (2) Ligand complexation reaction: 0.045 mol of tricyclohexylphosphine (PCy3) was added to the ruthenium salt solution and stirred at 40°C for 6 hours. (3) Introduction of additives: Add 10% of the mass of the active component of ethylaluminoxane (EAO) to the complexation solution and stir for 1.5 hours to form a homogeneous catalyst solution. (4) Crystallization and purification: After the reaction is completed, the solvent is removed by vacuum distillation, and a mixed solvent of n-hexane-diethyl ether (volume ratio 1:1.5) is added for recrystallization. After filtration, the solution is dried under vacuum at 55°C to obtain the target catalyst Cat-C2.

[0024] Comparative Example 3 Catalyst preparation (1) Preparation of ruthenium precursor solution: Under argon protection, 0.008 mol of bis(p-methylisopropylbenzene) ruthenium dichloride ([Ru(p-cymene)Cl2]2) was dissolved in 80 mL of toluene to form a solution with a concentration of 0.1 mol / L.

[0025] (2) Ligand complexation reaction: 0.004 mol of triphenylphosphine (PPh3) was added to the ruthenium salt solution and stirred at 25°C for 8 hours (the molar ratio of phosphine ligand to ruthenium salt was 0.5:1). (3) Introduction of additives: Add 5% by mass of methylaluminoxane (MAO) to the complexation solution and stir for 0.5 hours to form a homogeneous catalyst solution. (4) Crystallization and purification: After the reaction is completed, the solvent is removed by vacuum distillation, and a mixed solvent of n-hexane-diethyl ether (volume ratio 1:2.5) is added for recrystallization. After filtration, the solution is dried under vacuum at 45°C to obtain the target catalyst Cat-C3.

[0026] Experimental Testing: Application of Catalysts in Ring-Opening Metathesis Polymerization The catalysts prepared in Examples 1-3 and Comparative Examples 1-3 were reacted with cyclic olefin monomers under ring-opening metathesis polymerization conditions: Norbornene (NBE) and dicyclopentadiene (DCPD) were used as monomers. In a 500 mL dry reactor, the reaction system was purged three times with high-purity argon gas (flow rate 20 L / min, 5 min each time). 300 mL of cyclohexane, 0.1 mol of NBE, and 0.2 mol of DCPD were added; all reagents were purified and dried. The reactor was heated to 90 °C, and 7 mg of the catalyst was added to initiate the reaction. The stirring rate was set to 300 rpm, and the reaction was carried out for 3.5 h. Afterward, the mixture was rapidly cooled to room temperature, and 10 mL of a terminator (methanol) was added to terminate the reaction. The product was precipitated, washed, and vacuum dried to obtain the COP polymer. The yield and molecular weight of the polymer were recorded.

[0027] 1. Conversion rate: Determination of monomer amount before reaction: Accurately weigh the mass of the cyclic olefin monomer added to the reaction vessel and record it as m0; Determination of residual monomer content after reaction: After the polymerization reaction is completed and terminated, the reaction mixture is thoroughly dissolved (using tetrahydrofuran), and the concentration of residual monomer in the solution is determined by gas chromatography (GC). The mass of residual monomer is calculated based on the solution volume and concentration, and denoted as m1.

[0028] Conversion rate (%) = m0 - m1 / m0 × 100% 2. Determination of molecular weight and molecular weight distribution: The weight-average molecular weight (Mw), number-average molecular weight (Mn), and molecular weight distribution index (PDI, PDI = Mw / Mn) of the polymerized products were determined using gel permeation chromatography (GPC). The specific procedures are as follows: Sample preparation: Weigh an appropriate amount of the polymerization product and dissolve it in tetrahydrofuran (THF) to prepare a solution with a concentration of approximately 1.0 mg / mL. Sonicate the solution until completely dissolved, then filter through a 0.45 μm filter membrane for later use. Instrument conditions: Use a gel permeation chromatograph equipped with polystyrene standards for calibration. Use tetrahydrofuran as the mobile phase, set the flow rate to 1.0 mL / min, maintain the column temperature at 35 °C, and use an injection volume of 100 μL. Analyze the sample using the instrument software to obtain the Mw, Mn, and PDI values.

[0029] The content of byproducts was detected by gas chromatography (GC) using a flame ionization detector (FID), and the byproduct content was calculated using the area normalization method. Experimental results:

[0030] Conclusions: The yields of Cat-1, Cat-2, and Cat-3 all exceeded 89%, with Cat-1 achieving the highest yield of 91%. This indicates that the system can effectively drive the polymerization reaction forward and achieve efficient product formation and convenient recovery by suppressing side reactions. The polymers exhibit excellent molecular weights (number-average molecular weight Mn > 45,000 g / mol, weight-average molecular weight Mw > 90,000 g / mol), meeting the processing requirements of high-performance cyclic olefin polymers (COPs). Furthermore, their molecular weight distribution index (PDI) remained stable at around 2.0, consistent with the controllable chain growth kinetics of living polymerization, confirming that the catalyst system can achieve precise control over the polymer chain structure. In addition, the byproduct content was below 0.3%, further validating the system's high selectivity for the target polymerization reaction and effectively suppressing side reactions such as isomerization, oxidation, and oligomer formation.

[0031] The conversion rate of Cat-C1 dropped sharply to 60%, the number average molecular weight was 18000 g / mol, and the byproduct content was 1.2%, indicating that alkylaluminoxane promoters (MAO / EAO) help to further activate the ruthenium active center and promote the formation efficiency of associated active sites and the release of catalytic activity in the catalytic cycle.

[0032] The addition of Cat-C2 additives exceeding 10% can trigger alkylaluminum-mediated chain transfer side reactions, leading to abnormal changes in the polymer chain structure and significantly reducing product quality.

[0033] When the molar ratio of ligand to ruthenium salt in Cat-C3 is adjusted to <2:1, the chain transfer side reactions in the system are significantly aggravated, manifested by a sharp decrease in molecular weight, an increase in by-product content to 0.7%, and an increase in PDI value to 2.05. This indicates that a low ligand ratio may lead to a dynamic imbalance in the structure of the active center, which reduces the precision of the catalyst in regulating the chain growth process, thereby affecting the molecular structure and properties of the polymer.

[0034] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A catalyst for cyclic olefin polymers (COP), characterized in that, The catalyst comprises an active component and an auxiliary agent, wherein the active component is a homogeneous complex formed by a ruthenium salt and a phosphine ligand, and the ruthenium salt is selected from divalent or trivalent ruthenium; the auxiliary agent is an alkylaluminoxane compound, and its addition amount is 3%-8% of the mass of the active component.

2. The catalyst for cyclic olefin polymer COP according to claim 1, characterized in that, The phosphine ligand is selected from triphenylphosphine, tricyclohexylphosphine, 1,2-bis(diphenylphosphine)ethane or tritert-butylphosphine.

3. The catalyst for cyclic olefin polymer COP according to claim 1, characterized in that, The ruthenium salt is ruthenium trichloride, ruthenium acetate, or ruthenium dichloride (p-methylisopropylbenzene).

4. The catalyst for cyclic olefin polymer COP according to claim 1, characterized in that, In the complex, the molar ratio of phosphine ligand to ruthenium salt is (2-4):

1.

5. The catalyst for cyclic olefin polymer COP according to claim 1, characterized in that, The alkylaluminoxane compounds are selected from methylaluminoxane or ethylaluminoxane.

6. The method for preparing a catalyst for cyclic olefin polymers (COP) according to any one of claims 1-5, characterized in that, Includes the following steps: S1. Preparation of ruthenium precursor solution: Under argon protection, ruthenium salt is dissolved in an anhydrous organic solvent to form a solution with a concentration of 0.05-0.2 mol / L; S2, Ligand complexation reaction: Add the phosphine ligand to the ruthenium salt solution in step S1 and stir the reaction at 25-45℃ for 3-8 hours; S3, Additive introduction: Add alkylaluminoxane compound to the complexed solution of step S2, stir for 0.5-2 hours to form a homogeneous catalyst solution; S4. Crystallization and purification: After the reaction is completed, the solvent is removed by vacuum distillation, and the mixture of n-hexane and diethyl ether is added for recrystallization. After filtration, the mixture is dried under vacuum at 40-60℃ to obtain the target catalyst.

7. The method for preparing the catalyst for cyclic olefin polymers (COP) according to claim 6, characterized in that, The organic solvent in step S1 is one or more of tetrahydrofuran, dichloromethane, or toluene.

8. The method for preparing the catalyst for cyclic olefin polymer COP according to claim 6, characterized in that, In step S4, the volume ratio of n-hexane to diethyl ether is 1:(1-3).

9. The application of the catalyst according to any one of claims 1-5 for the COP polymerization of cyclic olefin polymers in the COP polymerization of cyclic olefin polymers, characterized in that, The application includes reacting the catalyst with cyclic olefin monomers under ring-opening metathesis polymerization conditions.

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