Metallocene catalyst, preparation method thereof and application of metallocene catalyst in olefin polymerization
By introducing aliphatic or aromatic groups into the cyclopentadiene ring of the metallocene catalyst and introducing amino groups to coordinate with the metal, the problem of low polymer molecular weight under high-temperature polymerization of existing metallocene catalysts is solved, and efficient olefin polymerization and the preparation of high molecular weight polymers are achieved.
Patent Information
- Application Number
- CN202510830950.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-06-20
- Publication Date
- 2025-10-10
AI Technical Summary
Although existing metallocene catalysts can ensure a high comonomer insertion rate under high-temperature polymerization conditions, the molecular weight of the resulting polymer is generally low, affecting the performance of polyolefin products.
The metallocene catalyst is prepared by a simple synthetic method by introducing aliphatic or aromatic groups into the cyclopentadiene ring of the metallocene catalyst, adjusting its spatial structure, and introducing amino groups to coordinate with the metal to improve the stability and activity of the catalyst.
The selectivity and catalytic activity in the olefin polymerization process are improved, the amount of catalyst used is reduced, and the molecular weight of the resulting polymer is significantly increased.
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Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of polyolefin material preparation, and in particular relates to a metallocene catalyst, a preparation method thereof, and application thereof in olefin polymerization. Background Art
[0002] High-end polyolefins are a key pillar of the polyolefin industry and a strategically important product for the national economies of developed countries worldwide. Large international multinational corporations are rapidly developing new technologies and releasing a steady stream of new products and brands, dominating the high-tech, high-value-added polyolefin market. This poses both a challenge and a driving force for the development of my country's polyolefin industry.
[0003] The rapid development of the polyolefin industry is largely due to advances in metallocene catalysts. The development and design of novel metallocene catalytic systems not only improves polyolefin production capacity and overall performance but also promotes the emergence of new polymerization processes and polyolefin products, expanding the application of polyolefins in a wider range of fields. While existing metallocene catalysts can achieve high comonomer insertion rates under high-temperature polymerization conditions, the resulting polymers generally have low molecular weights.
[0004] Therefore, research and development of high-performance catalytic systems are of great significance to improving the competitiveness of my country's high-end polyolefin market, breaking down technical barriers, and achieving localization. Summary of the Invention
[0005] In view of the defects of the prior art, the present invention provides a metallocene catalyst, a preparation method thereof and its application in olefin polymerization. The preparation process of the catalyst is simple and the cost is low. When the catalyst is used for olefin polymerization, the catalytic activity is good and the molecular weight of the obtained polymer is high.
[0006] A metallocene catalyst having the structural formula described in the following general formula 1: Formula 1, Where R1 is C1-C 10 Fatty acid groups, C6-C 20 Aryl, C3-C 10 Any one of the cycloalkyl groups; R2, R3, R4 or R5 is H, C1-C 10 Fatty acid groups, C6-C 20 Aryl, C3-C 10 any one of the cycloalkyl groups of , R2, R3, R4, and R5 are the same or different; X is a halogen, n is 2 or 3; M is selected from Ti, Zr, Hf, Sc, Fe, Co, Ni, Rh, Pd, or Ru; N is a nitrogen atom; It is a cyclopentadienyl group.
[0007] Preferably, the metallocene catalyst is any one of the following compounds (1) to (9): .
[0008] The preparation method of the metallocene catalyst comprises the following steps: (1) Adding raw material 1, catalyst pentamethylcyclopentadienyl rhodium dimer, and raw material 2 to a first organic solvent, reacting at 20-100°C for 1-10 hours to obtain intermediate 1; adding organic amine to intermediate 1, reacting at 30-100°C for 3-6 hours, filtering, concentrating, and recrystallizing to obtain intermediate 2; wherein, the first organic solvent is tetrahydrofuran or acetonitrile; the raw material 1 is a Michaelis acid methylene derivative having the following structural formula: The raw material 2 is an acetylene derivative having the following structural formula: The organic amine has the following structural formula: R1-NH2; the reaction mechanism is as follows: ; (2) Add a second organic solvent to the intermediate 2, add a strong alkaline substance thereto at -40 to 0°C, stir and react for 1-10 hours, add a halide of M at -20 to 40°C, continue to react for 3-24 hours, remove the solvent in vacuo, wash, and dry in vacuo to obtain the metallocene catalyst; wherein the second organic solvent is toluene, n-hexane or tetrahydrofuran.
[0009] Preferably, the molar ratio of the Michaelis acid methylene derivative, pentamethylcyclopentadienyl rhodium dimer, acetylene derivative and organic amine is 1:(0.01-0.1):(1-10):(1-10).
[0010] More preferably, the molar ratio of the Michaelis acid methylene derivative, pentamethylcyclopentadienyl rhodium dimer, acetylene derivative, and organic amine is 1:(0.01-0.1):(1-10):(1-8).
[0011] Preferably, the molar ratio of the intermediate 2, the strong base, and the halide of M is 1:(1.0-1.1):(0.6-2.0).
[0012] Preferably, the strong alkaline substance is sodium hydride, metallic sodium, metallic potassium or butyl lithium.
[0013] More preferably, in step (1), raw material 1, catalyst pentamethylcyclopentadienyl rhodium dimer, raw material 2 are added into the first organic solvent, and reacted at 20-80℃ for 1-5h to obtain intermediate 1; organic amine is added into intermediate 1, and reacted at 30-80℃ for 3-6h, filtered, concentrated, and recrystallized to obtain intermediate 2.
[0014] More preferably, in step (2), second organic solvent is added into intermediate 2, strong base is added into the second organic solvent at-40 to 0℃, stirred and reacted for 2-10h, halide of M is added at-10℃, and the reaction is continued for 8-22h, the solvent is removed under vacuum, washed, and dried under vacuum to obtain the metallocene catalyst.
[0015] The metallocene catalyst is used in olefin polymerization, which is ethylene homopolymerization or copolymerization of ethylene and α-olefin.
[0016] Preferably, the olefin polymerization is carried out as follows: under the atmosphere of inert gas, n-hexane, the metallocene catalyst, and cocatalyst are added into an autoclave, and then polymerization raw material is added, stirred, and reacted at 100-200℃ for 5-35min.
[0017] Preferably, the cocatalyst is trimethylaluminum or methylaluminoxane.
[0018] Preferably, the mass ratio of the metallocene catalyst to the cocatalyst is 1: (2-10); when the olefin polymerization is ethylene homopolymerization, the polymerization raw material is ethylene, ethylene is added to a pressure of 0.5-1.0MPa, and the volume of the autoclave, the volume of n-hexane, and the mass of the metallocene catalyst are in the ratio of 1L:0.5L:1.6-3.0mg; When the olefin polymerization is copolymerization of ethylene and α-olefin, the polymerization raw material is ethylene and α-olefin, ethylene is added to a pressure of 0.5-1.0MPa, and the volume of the autoclave, the volume of n-hexane, the mass of the metallocene catalyst, and the mass of α-olefin are in the ratio of 1L:0.5L:1.6-3.0mg:5-10mL.
[0019] Advantages of the present application: The present application introduces aliphatic group or aromatic group on the metallocene catalyst to adjust the space structure of the metallocene catalyst, improve the selectivity of the metallocene catalyst in the process of olefin polymerization, introduces amino group on the metallocene catalyst to coordinate with the metal, improve the stability of the metal in the metallocene catalyst, enhance the activity and stability of the metallocene catalyst in the process of olefin polymerization, and reduce the amount of the catalyst. The synthesis method is simple, the production cost is low, the catalytic activity is good when used in the process of olefin polymerization, and the molecular weight of the obtained polymer is high. DETAILED DESCRIPTION
[0020] Example 1 R1 is phenyl, R2, R3, R4, and R5 are H, X is Cl, and M is Ti, which is the compound (1) of the present invention; The preparation method of the compound (1) comprises the following steps: (1) Add 850 mg (5.0 mmol) of raw material 1 (R2 and R3 are H) and 31 mg (0.05 mmol) of catalyst pentamethylcyclopentadienyl rhodium dimer to 60 mL of tetrahydrofuran, introduce 50 mmol of acetylene gas into the solution, and react at 40 °C for 3 h to obtain intermediate 1; add 558 mg (6.0 mmol) of aniline to intermediate 1, react at 50 °C for 5 h, filter, concentrate, and recrystallize from ethyl acetate to obtain 833 mg (4.5 mmol) of intermediate 2, with a yield of 90%; (2) 370 mg (2.0 mmol) of intermediate 2 was added to 15 mL of toluene, and 2.0 mmol of sodium hydride was added to the mixture at -10°C. The mixture was stirred and reacted for 3 h. 1.8 mmol of titanium tetrachloride was added at -10°C and the reaction was continued for 10 h. The solvent was removed in vacuo, and the mixture was washed three times with 80 mL of petroleum ether and dried in vacuo to obtain 517 mg (1.5 mmol) of the metallocene catalyst described in compound (1). The yield was 73.5%. The results of the nuclear magnetic resonance examination are as follows: 1 HNMR(400MHz, CDCl3:7.26ppm): δ =7.69-7.46 (m, 4H); 7.24 (m, 1H); 6.50-6.42 (m, 4H); Anal.Calcd.(%) for C 12 H9Cl3NOTi: C, 42.72; H, 2.69; found: C, 42.73; H, 2.72.
[0021] Example 2 R1 is cyclopentyl, R2, R3, R4, and R5 are methyl, X is Cl, and M is Zr, which is the compound (2) of the present invention; The preparation method of the compound (2) comprises the following steps: (1) Add 990 mg (5.0 mmol) of raw material 1 (R2 and R3 are methyl groups), 43 mg (0.07 mmol) of catalyst pentamethylcyclopentadienyl rhodium dimer, and 324 mg (6.0 mmol) of 2-butyne to 60 mL of tetrahydrofuran, and react at 20°C for 3 h to obtain intermediate 1; add 681 mg (8.0 mmol) of cyclopentylamine to intermediate 1, react at 60°C for 5 h, filter, concentrate, and recrystallize from ethyl acetate to obtain 990 mg (4.25 mmol) of intermediate 2, with a yield of 85%; (2) 465 mg (2.0 mmol) of intermediate 2 was added to 15 mL of tetrahydrofuran, and 2.0 mmol of sodium hydride was added to the mixture at 0°C. The mixture was stirred for 2 h, and 2.2 mmol of zirconium tetrachloride was added at -10°C. The reaction was continued for 8 h. The solvent was removed in vacuo, and the mixture was washed three times with 80 mL of petroleum ether and dried in vacuo to obtain 614 mg (1.38 mmol) of the metallocene catalyst described as compound (2) with a yield of 69.2%. The results of the nuclear magnetic resonance examination are as follows: 1 HNMR(400MHz, CDCl3:7.26ppm): δ = 3.72-3.70 (m, 1H); 2.13 (s, 6H); 1.76(s, 6H); 1.72-1.50 (m, 8H); Anal.Calcd.(%) for C 15 H 21 Cl3NOZr: C, 42.01; H, 4.94; found: C, 42.21; H, 4.93.
[0022] Example 3 R1 is ethyl, R2 and R5 are H, R3 and R4 are phenyl, X is Cl; M is Rh, which is the compound (3) of the present invention; The preparation method of the compound (3) comprises the following steps: (1) Add 1231 mg (5.0 mmol) of raw material 1 (R2 is H, R3 is phenyl), 61.8 mg (0.1 mmol) of catalyst pentamethylcyclopentadienyl rhodium dimer, and 1020 mg (10.0 mmol) of phenylacetylene to 60 mL of acetonitrile, and react at 80 ° C for 2 h to obtain intermediate 1; add 902 mg (20.0 mmol) of ethylamine to intermediate 1, react at 50 ° C for 5 h, filter, concentrate, and recrystallize from ethyl acetate to obtain 1331 mg (4.6 mmol) of intermediate 2, with a yield of 92%; (2) Take 579 mg (2.0 mmol) of intermediate 2, add 15 mL of n-hexane, add 2.0 mmol of sodium metal at 0°C, stir for 10 h, add 1.2 mmol of rhodium trichloride at -10°C, continue to react for 15 h, remove the solvent under vacuum, wash with 80 mL of petroleum ether for 3 times, dry under vacuum to obtain 705 mg (1.48 mmol) of metallocene catalyst as described in compound (3), the yield is 74.2%; The nuclear magnetic detection results are as follows: 1 HNMR (400MHz, CDCl3: 7.26ppm): δ = 7.40-7.35 (m, 6H); 7.17-7.12 (m, 4H); 6.70 (s, 1H); 6.68 (s, 1H); 3.22 (q, 2H); 1.20 (t, 3H); Anal. Calcd. (%) for C 20 H 17 Cl2NORh: C, 52.09; H, 3.72; found: C, 52.00; H, 3.71.
[0023] Example 4 R1, R2, R3, R4, R5 are all phenyl; X is Cl; M is Ti, which is compound (4) described in the application; The preparation method of the compound (4) comprises the following steps: (1) Add 1612 mg (5.0 mmol) of raw material 1 (R2, R3 is phenyl), a catalyst of pentamethylcyclopentadienyl rhodium dimer 123.6 mg (0.2 mmol), and diphenylacetylene 891 mg (5.0 mmol) to 60 mL of tetrahydrofuran, react at 45°C for 4 h to obtain intermediate 1; add 930 mg (10.0 mmol) of aniline to intermediate 1, react at 60°C for 5 h, filter, concentrate, and recrystallize in ethyl acetate to obtain 2056 mg (4.2 mmol) of intermediate 2, the yield is 84%; (2) Take 979 mg (2.0 mmol) of intermediate 2, add 15 mL of tetrahydrofuran, add 2.2 mmol of sodium hydride at -40°C, stir for 6 h, add 4.0 mmol of titanium tetrachloride at -10°C, continue to react for 15 h, remove the solvent under vacuum, wash with 80 mL of petroleum ether for 3 times, dry under vacuum to obtain 965 mg (1.47 mmol) of metallocene catalyst as described in compound (4), the yield is 73.5%; The nuclear magnetic detection results are as follows: 1HNMR(400MHz, CDCl3:7.26ppm): δ = 7.67 (d, 2H); 7.45-7.26 (m, 11H); 7.20-7.06 (m, 12H); Anal.Calcd.(%) for C 36 H 25 Cl3NOTi: C, 67.37; H, 3.93; found: C, 67.00; H, 3.88.
[0024] Example 5 R1 is cyclohexyl, R4 and R5 are phenyl; R2 and R3 are both H, X is Cl; M is Ru, which is the compound (5) of the present invention; The preparation method of the compound (5) comprises the following steps: (1) Add 851 mg (5.0 mmol) of raw material 1 (R2 and R3 are H), 61.8 mg (0.1 mmol) of catalyst pentamethylcyclopentadienyl rhodium dimer, and 2464 mg (30.0 mmol) of 3-hexyne to 60 mL of acetonitrile, and react at 50 ° C for 4 h to obtain intermediate 1; add 2479 mg (25.0 mmol) of cyclohexylamine to intermediate 1, react at 60 ° C for 3 h, filter, concentrate, and recrystallize from ethyl acetate to obtain 1614 mg (4.7 mmol) of intermediate 2, with a yield of 94%; (2) Take 687 mg (2.0 mmol) of intermediate 2, add 15 mL of toluene, add 2.0 mmol of butyl lithium at -30 ° C, stir and react for 9 h, add 3.0 mmol of ruthenium trichloride at -10 ° C, continue to react for 20 h, remove the solvent in vacuo, wash with 80 mL of petroleum ether three times, and dry in vacuo to obtain 722 mg (1.67 mmol) of the metallocene catalyst described as compound (5), with a yield of 83.5%; The results of the nuclear magnetic resonance examination are as follows: 1 HNMR(400MHz, CDCl3:7.26ppm): δ = 6.56 (d, 1H); 6.50 (d, 1H); 3.55 (m,1H); 2.12 (q, 4H); 1.91-1.22 (m, 10H); 0.8 (t, 6H); Anal.Calcd.(%) forC 16 H 23 Cl2NORu: C, 46.05; H, 5.56; found: C, 46.01; H, 5.66.
[0025] Example 6 R1 is n-pentyl, R2 and R5 are H, R3 is cyclohexyl, R4 is methyl, X is Cl, and M is Hf, which is the compound (6) of the present invention; The preparation method of the compound (6) comprises the following steps: (1) Add 1261 mg (5.0 mmol) of raw material 1 (R2 is H, R3 is cyclohexyl) and 185.4 mg (0.3 mmol) of catalyst pentamethylcyclopentadienyl rhodium dimer to 60 mL of acetonitrile, introduce 50.0 mmol of propyne gas into the solution, and react at 30°C for 5 h to obtain intermediate 1; add 3486 mg (40.0 mmol) of n-pentylamine to intermediate 1, react at 40°C for 6 h, filter, concentrate, and recrystallize from ethyl acetate to obtain 1074 mg (3.9 mmol) of intermediate 2, with a yield of 78%; (2) Take 551 mg (2.0 mmol) of intermediate 2, add 15 mL of toluene, add 2.2 mmol of sodium metal at 0°C, stir and react for 10 h, add 2.0 mmol of hafnium tetrachloride at -10°C, continue to react for 12 h, remove the solvent in vacuo, wash with 80 mL of petroleum ether three times, and dry in vacuo to obtain 808 mg (1.41 mmol) of the metallocene catalyst described as compound (6), with a yield of 70.5%; The results of the nuclear magnetic resonance examination are as follows: 1 HNMR(400MHz, CDCl3:7.26ppm): δ = 6.33 (s, 1H); 6.27 (s, 1H); 3.10 (t,2H); 2.17 (s, 3H); 2.14 (t, 2H); 1.60-1.21 (m, 16H); 0.8 (t, 3H); Anal.Calcd.(%) for C 18 H 27 Cl3NOHf: C, 50.56; H, 6.36; found: C, 50.55; H, 6.41.
[0026] Example 7 R1 is tert-butyl, R2 and R4 are H, R3 is phenyl, R5 is methyl, X is Cl, and M is Ni, which is the compound (7) of the present invention; The preparation method of the compound (7) comprises the following steps: (1) Add 1231 mg (5.0 mmol) of raw material 1 (R2 is phenyl, R3 is H) and 61.8 mg (0.1 mmol) of catalyst pentamethylcyclopentadienyl rhodium dimer to 60 mL of tetrahydrofuran, introduce 45.0 mmol of propyne gas into the solution, and react at 40°C for 3 h to obtain intermediate 1; add 2925 mg (40.0 mmol) of tert-butylamine to intermediate 1, react at 40°C for 6 h, filter, concentrate, and recrystallize from ethyl acetate to obtain 996 mg (3.9 mmol) of intermediate 2, with a yield of 78%; (2) Take 511 mg (2.0 mmol) of intermediate 2, add 15 mL of n-hexane, add 2.0 mmol of potassium metal at -15 ° C, stir and react for 5 h, add 4.0 mmol of nickel trichloride at -10 ° C, continue to react for 14 h, remove the solvent in vacuo, wash with 80 mL of petroleum ether three times, and dry in vacuo to obtain 612 mg (1.55 mmol) of the metallocene catalyst described as compound (7), with a yield of 77.5%; The results of the nuclear magnetic resonance examination are as follows: 1 HNMR(400MHz, CDCl3:7.26ppm): δ = 7.21-7.16 (m, 3H); 7.01 (d, 2H); 6.88(d, 1H); 6.56 (d, 1H); 1.99 (s, 3H); 1.45 (s, 9H); Anal.Calcd.(%) forC 17 H 19 Cl2NONi: C, 53.32; H, 5.00; found: C, 53.30; H, 5.05.
[0027] Example 8 R1 is 1-naphthyl, R2 and R4 are H, R3 is ethyl, R5 is methyl, X is Cl, and M is Co, which is the compound (8) of the present invention; The preparation method of the compound (8) comprises the following steps: (1) Add 991 mg (5.0 mmol) of raw material 1 (R2 is hydrogen, R3 is ethyl), 92.7 mg (0.15 mmol) of catalyst pentamethylcyclopentadienyl rhodium dimer, and 2042 mg (20.0 mol) of phenylacetylene to 60 mL of tetrahydrofuran, and react at 80°C for 1 h to obtain intermediate 1; add 1432 mg (10.0 mmol) of 1-naphthylamine to intermediate 1, react at 80°C for 6 h, filter, concentrate, and recrystallize from ethyl acetate to obtain 1276 mg (4.6 mmol) of intermediate 2, with a yield of 92%; (2) Take 555 mg (2.0 mmol) of intermediate 2, add 15 mL of tetrahydrofuran, add 2.2 mmol of butyl lithium at -25 ° C, stir and react for 7 h, add 2.5 mmol of cobalt trichloride at -10 ° C, continue to react for 22 h, remove the solvent in vacuo, wash with 80 mL of petroleum ether three times, and dry in vacuo to obtain 637 mg (1.32 mmol) of the metallocene catalyst described as compound (8), with a yield of 66.1%; The results of the nuclear magnetic resonance examination are as follows: 1 HNMR(400MHz, CDCl3:7.26ppm): δ = 8.21-8.15 (m, 4H); 7.68-7.44 (m, 3H); 7.27-7.16 (m, 5H); 7.00 (s, 1H); 6.22 (s, 1H); 2.05 (q, 2H); 0.81 (t, 3H);Anal.Calcd.(%) forC 24 H 19 Cl2NOCo: C, 61.69; H, 4.10; found: C, 61.70; H, 4.07.
[0028] Example 9 R1 is phenyl, R2, R4, and R5 are H, R3 is methyl, X is Cl, and M is Sc, which is the compound (9) of the present invention; The preparation method of the compound (9) comprises the following steps: (1) Add 921 mg (5.0 mmol) of raw material 1 (R2 is H, R3 is methyl) and 309 mg (0.5 mol) of catalyst pentamethylcyclopentadienyl rhodium dimer to 60 mL of acetonitrile, introduce 35.0 mmol of acetylene gas into the solution, and react at 20 ° C for 4 h to obtain intermediate 1; add 931 mg (10.0 mmol) of aniline to intermediate 1, react at 30 ° C for 6 h, filter, concentrate, and recrystallize from ethyl acetate to obtain 618 mg (3.1 mmol) of intermediate 2, with a yield of 62%; (2) 399 mg (2.0 mmol) of intermediate 2 was added to 15 mL of toluene, and 2.0 mmol of sodium hydride was added to the intermediate at 0°C. The mixture was stirred and reacted for 8 h. 1.8 mmol of scandium trichloride was added at -10°C and the reaction was continued for 12 h. The solvent was removed in vacuo, and the mixture was washed three times with 80 mL of petroleum ether and dried in vacuo to obtain 466 mg (1.42 mmol) of the metallocene catalyst described as compound (9) with a yield of 71.1%. The results of the nuclear magnetic resonance examination are as follows: 1HNMR(400MHz, CDCl3:7.26ppm): δ = 7.77 (d, 2H); 7.50 (t, 2H); 7.21 (d,1H); 6.66 (d, 1H); 6.59 (d, 1H); 6.17 (s, 1H); 2.22 (s, 3H); Anal.Calcd.(%)for C 13 H 11 Cl2NOSc: C, 49.87; H, 3.54; found: C, 49.95; H, 3.60.
[0029] Example 10 A method for preparing an ethylene homopolymer is as follows: After the 10 L stainless steel autoclave was fully replaced with nitrogen, 5 L of n-hexane, 18 mg of the metallocene catalyst of compound (1) prepared in Example 1 and 50 mg of trimethylaluminum were added to the autoclave, ethylene was introduced to a pressure of 0.7 MPa, and the mixture was stirred and heated to 100° C. for 10 min. The polymerization product was collected.
[0030] Example 11 A method for preparing a copolymer of ethylene and 1-hexene is as follows: After the 10 L stainless steel autoclave was fully replaced with nitrogen, 5 L of n-hexane, 25 mg of the metallocene catalyst of compound (2) prepared in Example 2, and 60 mg of trimethylaluminum were added to the reactor, and 100 mL of 1-hexene was added. Ethylene was introduced to a pressure of 1.0 MPa, and the mixture was stirred and heated to 155° C. for reaction for 5 min. The polymerization product was collected.
[0031] Example 12 A method for preparing an ethylene and 1-octene copolymer is as follows: After the 10 L stainless steel autoclave was fully replaced with nitrogen, 5 L of n-hexane, 23 mg of the metallocene catalyst of compound (3) prepared in Example 3, and 78 mg of methylaluminoxane were added to the reactor, and 100 mL of 1-octene was added. Ethylene was introduced to a pressure of 0.7 MPa, and the mixture was stirred and heated to 170° C. for reaction for 30 min. The polymerization product was collected.
[0032] Example 13 A method for preparing an ethylene and 1-octene copolymer is as follows: After the 10 L stainless steel autoclave was fully replaced with nitrogen, 5 L of n-hexane, 30 mg of the metallocene catalyst of compound (4) prepared in Example 4, and 70 mg of methylaluminoxane were added to the reactor, and 100 mL of 1-octene was added. Ethylene was introduced to a pressure of 0.7 MPa, and the mixture was stirred and heated to 160° C. for reaction for 20 min. The polymerization product was collected.
[0033] Example 14 A method for preparing an ethylene-styrene copolymer is as follows: After the 10 L stainless steel autoclave was fully replaced with nitrogen, 5 L of n-hexane, 18 mg of the metallocene catalyst of compound (5) prepared in Example 5, and 99 mg of trimethylaluminum were added to the reactor, and 90 mL of styrene was added. Ethylene was introduced to a pressure of 0.8 MPa, and the mixture was stirred and heated to 145°C for 10 min. The polymerization product was collected.
[0034] Example 15 A method for preparing a copolymer of ethylene and 1-nonene is as follows: After the 10 L stainless steel autoclave was fully replaced with nitrogen, 5 L of n-hexane, 23 mg of the metallocene catalyst of compound (6) prepared in Example 6, and 100 mg of trimethylaluminum were added to the reactor, and 100 mL of 1-nonene was added. Ethylene was introduced to a pressure of 0.7 MPa, and the mixture was stirred and heated to 110° C. for 15 min. The polymerization product was collected.
[0035] Example 16 A method for preparing a copolymer of ethylene and 1-butene is as follows: After the 10 L stainless steel autoclave was fully replaced with nitrogen, 5 L of n-hexane, 16 mg of the metallocene catalyst of compound (7) prepared in Example 7, and 70 mg of trimethylaluminum were added to the reactor, and 100 mL of 1-butene was added. Ethylene was introduced to a pressure of 0.8 MPa, and the mixture was stirred and heated to 190°C for reaction for 5 min. The polymerization product was collected.
[0036] Example 17 A method for preparing a copolymer of ethylene and 1-heptene is as follows: After the 10 L stainless steel autoclave was fully replaced with nitrogen, 5 L of n-hexane, 19 mg of compound (8) metallocene catalyst, 42 mg of methylaluminoxane and 100 mL of 1-heptene were added to the reactor. Ethylene was introduced to a pressure of 0.7 MPa. The mixture was stirred and heated to 185 °C for 25 min. The polymerization product was collected.
[0037] Example 18 A method for preparing a copolymer of ethylene and 1-butene is as follows: After the 10 L stainless steel autoclave was fully replaced with nitrogen, 5 L of n-hexane, 24 mg of the metallocene catalyst of compound (9) prepared in Example 8, and 100 mg of methylaluminoxane were added to the reactor, and 90 mL of 1-butene was added. Ethylene was introduced to a pressure of 0.8 MPa, and the mixture was stirred and heated to 120°C for 35 min. The polymerization product was collected.
[0038] Comparative Example 1 The metallocene catalyst was replaced by titanocene dichloride, and the rest was the same as in Example 10.
[0039] Comparative Example 2 The metallocene catalyst was replaced by cyclopentadienyl zirconium trichloride, and the rest was the same as in Example 11.
[0040] The polyolefins prepared in Examples 10-18 and Comparative Examples 1-2 were subjected to performance tests. The results are shown in Table 1 below.
[0041] Table 1 Polymer detection results As can be seen in Table 1, the polymers prepared in Examples 10-18 exhibited good polymerization activity and high weight-average molecular weights, demonstrating that the metallocene catalysts of the present invention have good catalytic activity for both ethylene homopolymerization and ethylene-α-olefin copolymerization. Compared to Examples 10 and 11, the catalysts of Comparative Examples 1 and 2 exhibited lower polymerization activity and lower polymer weight-average molecular weights, further demonstrating that the metallocene catalysts prepared in accordance with the present invention exhibit superior catalytic activity compared to conventional metallocene catalysts.
Claims
1. A metallocene catalyst, characterized in that: The metallocene catalyst has the structural formula described in the following general formula 1: Formula 1, Where R1 is C1-C 10 Fatty acid groups, C6-C 20 Aryl, C3-C 10 Any one of the cycloalkyl groups; R2, R3, R4 or R5 is H, C1-C 10 Fatty acid groups, C6-C 20 Aryl, C3-C 10 any one of the cycloalkyl groups of , R2, R3, R4, and R5 are the same or different; X is a halogen, n is 2 or 3; M is selected from Ti, Zr, Hf, Sc, Fe, Co, Ni, Rh, Pd, or Ru; N is a nitrogen atom; It is a cyclopentadienyl group.
2. The metallocene catalyst according to claim 1, wherein: The metallocene catalyst is any one of the following compounds (1) to (9): 。 3. The method for preparing the metallocene catalyst according to claim 1, wherein: The following steps are involved: (1) Adding raw material 1, catalyst pentamethylcyclopentadienyl rhodium dimer, and raw material 2 to a first organic solvent, reacting at 20-100°C for 1-10 hours to obtain intermediate 1; adding organic amine to intermediate 1, reacting at 30-100°C for 3-6 hours, filtering, concentrating, and recrystallizing to obtain intermediate 2; wherein, the first organic solvent is tetrahydrofuran or acetonitrile; the raw material 1 is a Michaelis acid methylene derivative having the following structural formula: The raw material 2 is an acetylene derivative having the following structural formula: ; The organic amine has the following structural formula: R1-NH2; (2) Add a second organic solvent to the intermediate 2, add a strong alkaline substance thereto at -40 to 0°C, stir and react for 1-10 hours, add a halide of M at -20 to 40°C, continue to react for 3-24 hours, remove the solvent in vacuo, wash, and dry in vacuo to obtain the metallocene catalyst; wherein the second organic solvent is toluene, n-hexane or tetrahydrofuran.
4. The method for preparing the metallocene catalyst according to claim 3, wherein: The molar ratio of the Michaelis acid methylene derivative, pentamethylcyclopentadienyl rhodium dimer, acetylene derivative and organic amine is 1: (0.01-0.1): (1-10): (1-10).
5. The method for preparing the metallocene catalyst according to claim 4, wherein: The molar ratio of the intermediate 2, the strong base, and the halide of M is 1:(1.0-1.1):(0.6-2.0).
6. The method for preparing the metallocene catalyst according to claim 5, wherein: The strong alkaline substance is sodium hydride, metallic sodium, metallic potassium or butyl lithium.
7. Use of the metallocene catalyst according to claim 1 in olefin polymerization, characterized in that: The olefin polymerization is ethylene homopolymerization or ethylene and α-olefin copolymerization.
8. The use of the metallocene catalyst in olefin polymerization according to claim 7, characterized in that: The olefin polymerization is specifically as follows: under an inert gas atmosphere, n-hexane, the metallocene catalyst, and a co-catalyst are added into an autoclave, followed by polymerization raw materials, stirring, and reacting at 100-200° C. for 5-35 minutes.
9. Use of the metallocene catalyst in olefin polymerization according to claim 8, characterized in that: The co-catalyst is trimethylaluminum or methylaluminoxane.
10. Use of the metallocene catalyst in olefin polymerization according to claim 9, characterized in that: The mass ratio of the metallocene catalyst to the cocatalyst is 1:(2-10); when the olefin polymerization is ethylene homopolymerization, the polymerization raw material is ethylene, ethylene is added to a pressure of 0.5-1.0 MPa, and the volume of the autoclave, the volume of n-hexane, and the mass ratio of the metallocene catalyst are 1 L:0.5 L:1.6-3.0 mg; When the olefin polymerization is copolymerization of ethylene and α-olefin, the polymerization raw materials are ethylene and α-olefin, ethylene is added to a pressure of 0.5-1.0 MPa, and the volume of the autoclave, the volume of n-hexane, the mass of the metallocene catalyst, and the mass ratio of α-olefin are 1 L:0.5 L:1.6-3.0 mg:5-10 mL.