Metallocene catalyst, and preparation method therefor and use thereof

Abstract

The present invention provides a metallocene catalyst, and a preparation method therefor and the use thereof. The metallocene catalyst has the structural formula of formula (I), wherein R1 and R2 are each independently selected from H or an alkyl having 1 to 20 carbon atoms; R3 is selected from Cy or tBu; R4 and R5 are each independently selected from a halogen or an alkyl having 1 to 20 carbon atoms; and M is selected from Ti, Zr or Hf. In the present invention, the steric hindrance effect of the substituent on the amine group, the steric hindrance effect on the metallocene ring, and the electronic effect are synergized, thereby improving the high-temperature resistance and polymerization activity of the catalyst.

Description

A metallocene catalyst, its preparation method and application Technical Field

[0001] This invention relates to a metallocene catalyst, its preparation method, and its application, belonging to the field of olefin polymerization technology. Background Technology

[0002] With the rapid development of the polyolefin industry, polyolefin elastomers (POEs) have attracted widespread research and attention from researchers in the plastics field due to their excellent properties. POE is an elastomer obtained by random copolymerization of ethylene and α-olefins (such as 1-butene, 1-hexene, or 1-octene). Because its molecular chain contains both polyethylene crystalline segments that act as physical crosslinking points at room temperature and amorphous regions formed by the random copolymerization segments of ethylene and α-olefins, POE exhibits the high elasticity of rubber without vulcanization at room temperature, and can undergo plastic flow at temperatures above the melting temperature of polyethylene segments, making it a thermoplastic elastomer. POE molecular chains are saturated, exhibiting excellent weather resistance, ozone resistance, and UV aging resistance. Its narrow molecular weight distribution makes it less prone to warping and deformation during processing and molding.

[0003] Ethylene-octene copolymers (POEs) are a rapidly developing class of polyolefin elastomers, currently widely used in the preparation of radiator grilles, door and window sealing materials, dashboard skins, wheel covers, and door sill plates. POE filled with aluminum hydroxide or magnesium hydroxide can be used to produce halogen-free flame-retardant cable materials. Meanwhile, due to the rapid development of solar energy, developing high-performance photovoltaic encapsulation materials is crucial for extending the lifespan of photovoltaic cells. POE films possess advantages such as excellent PID resistance, high resistivity, high water vapor barrier properties, excellent aging resistance, and good sealing performance, making them an ideal material for photovoltaic films. They have become a substitute for ethylene-vinyl acetate (EVA), a commonly used photovoltaic encapsulation material, and demand continues to grow.

[0004] Polyolefin elastomers are typically prepared using metallocene catalysts, with the bridged monometallic defined geometry (CGC) catalyst from Dow Chemical Company being a typical example. This catalyst is characterized by its simple synthetic route and excellent homopolymerization and copolymerization performance. Due to the low crystallinity and scattered bundle morphology of polyolefin elastomers, solution polymerization is usually employed. In solution polymerization systems, increasing the temperature not only significantly improves the polymer's solubility in the solvent and reduces the viscosity of the solution system, preventing polymer precipitation and blockage of pipelines, but also facilitates the separation of subsequent products. High-temperature solution systems can directly flash evaporate polyolefin elastomers without heating, reducing energy consumption and significantly improving economic efficiency.

[0005] Although high-temperature solution polymerization is more economical and efficient in industrial production, traditional CGC catalysts still have limitations in terms of stability and catalytic activity at high temperatures. Typically, these catalysts can only withstand 150°C; when the polymerization temperature exceeds 160°C, the catalyst deactivates rapidly, resulting in a lower molecular weight polymer.

[0006] The common strategy for developing high-temperature resistant polyolefin elastomer catalysts is to increase the steric hindrance effect on the cyclic ring and the substituents on the amine group to improve the catalyst's temperature resistance. However, simultaneously increasing the steric hindrance effect on both the cyclic ring and the substituents on the amine group leads to a decrease in the insertion rate of the sterically hindered α-olefin monomer. Therefore, it is necessary to synergistically optimize the steric hindrance effects on the cyclic ring and the substituents on the amine group, based on the specific bridging structure, to achieve a high-temperature resistant polyolefin elastomer catalyst with strong copolymerization ability. Furthermore, increasing the polymerization temperature increases the chain transfer rate, and the molecular weight of the POE polymer polymerized at high temperatures decreases significantly, thus presenting a dilemma between high-temperature resistant catalysts and the molecular weight of POE polymers.

[0007] Therefore, developing high-temperature resistant and easily synthesized polyolefin elastomer catalysts is of great significance for the industrialization of POE. Summary of the Invention

[0008] To address the aforementioned technical problems, the present invention aims to provide a metallocene catalyst, its preparation method, and its applications. The metallocene catalyst of the present invention can catalyze the copolymerization of ethylene and α-olefins at high temperatures to prepare polyolefin elastomers with high insertion rates and high molecular weights.

[0009] To achieve the above objectives, in a first aspect, the present invention provides a metallocene catalyst, wherein the metallocene catalyst has a structure as shown in formula (I):

[0010] In equation (I), R 1 and R 2 Each is independently selected from H or an alkyl group having 1 to 20 carbon atoms, R 1 and R 2 Same or different;

[0011] R 3 Selected from cyclohexyl (Cy) or tert-butyl (Tb) t Bu;

[0012] R 4 and R 5 Each is independently selected from halogens or alkyl groups having 1 to 20 carbon atoms, R 4 and R 5 Same or different; M is selected from Ti, Zr or Hf, preferably Ti.

[0013] According to a specific embodiment of the present invention, preferably, in formula (I), R 1 and R 2 Each is independently selected from alkyl groups having 1 to 10 carbon atoms; more preferably alkyl groups having 1 to 5 carbon atoms; more preferably alkyl groups having 1 to 3 carbon atoms; and most preferably Me.

[0014] According to a specific embodiment of the present invention, preferably, in formula (I), X1 and X2 are each independently selected from F, Cl or Br; more preferably Cl or Me.

[0015] According to a specific embodiment of the present invention, preferably, in formula (I), R 1 and R 2 Each is independently selected from H or Me; R 3 Selected from cyclohexyl (Cy) or tert-butyl (Tb) t Bu;R 4 and R 5 Each is independently selected from Me or Cl.

[0016] According to a specific embodiment of the present invention, preferably, the metallocene catalyst is one of the compounds with the structures shown in the following formulas: Ti1-Ti8, Zr6, and Hf6.

[0017] Ti1,R 1 For H, R 2 For H, R 3 For Cy, R 4 For Cl, R 5 For Cl;

[0018] Ti2,R 1 For Me, R 2 For Me, R 3 For Cy, R 4 For Cl, R 5 For Cl;

[0019] Ti3, R 1 For Me, R 2 For H, R 3 For Cy, R 4 For Cl, R 5 For Cl;

[0020] Ti4,R 1 For Me, R 2 For Me, R 3 for t Bu, R 4 For Cl, R 5 For Cl;

[0021] Ti5, R 1For H, R 2 For H, R 3 For Cy, R 4 For Me, R 5 For Me;

[0022] Ti6, R 1 For Me, R 2 For Me, R 3 For Cy, R 4 For Me, R 5 For Me;

[0023] Ti7, R 1 For Me, R 2 For H, R 3 For Cy, R 4 For Me, R 5 For Me;

[0024] Ti8, R 1 For Me, R 2 For Me, R 3 for t Bu, R 4 For Me, R 5 For Me;

[0025] Zr6,R 1 For Me, R 2 For Me, R 3 For Cy, R 4 For Me, R 5 For Me;

[0026] Hf6, R 1 For Me, R 2 For Me, R 3 For Cy, R 4 For Me, R 5 For Me.

[0027] Using the metallocene catalyst of this invention, which employs a thiophene fused ring bridged with a rigid benzene ring, the copolymerization of ethylene and 1-octene can be highly active at high temperatures through the synergistic effects of steric hindrance from the substituents on the amine group, the steric hindrance effect on the cyclopentadienyl ring, and electronic effects, yielding polyolefin elastomers with high monomer insertion rates. In comparison (Ti2 vs. Ti4, Ti6 vs. Ti8), the cyclohexyl-substituted catalyst exhibits higher polymerization activity and produces copolymers with higher molecular weights. Due to the lower steric hindrance of the cyclohexyl group, the α-olefin insertion rate of the polymer is higher at high temperatures; this is a result of the synergistic effect of the substituents on the cyclopentadienyl ring and the steric hindrance effect of the substituents on the amine group.

[0028] Secondly, the present invention also provides a method for preparing the above-mentioned metallocene catalyst, which includes the following steps:

[0029] Under a protective atmosphere, a metallocene catalyst with the structure shown in formula (I) was prepared by reacting compound L with organolithium and metal halide M.

[0030] The structure of compound L is as follows:

[0031] R in compound L 1 R 2 R 3 Respectively with R in equation (I) 1 R 2 R 3 same;

[0032] The M metal halide is selected from the chlorides of Ti, Zr, or Hf.

[0033] According to a specific embodiment of the present invention, preferably, under a protective atmosphere, an organolithium compound is added to a solution containing compound L at -10°C to -40°C; then, a metal halide M is added at -40°C to -78°C, and the metallocene catalyst of formula (I) is prepared by reaction; more preferably, under nitrogen protection, an organolithium compound is added to a solution containing compound L at -30°C, and then, a metal halide M is added at -30°C, to prepare the metallocene catalyst of formula (I).

[0034] According to a specific embodiment of the present invention, preferably, under a protective atmosphere, an organolithium compound is added to a solution containing compound L and reacted at room temperature for 2-18 hours, preferably 12 hours; then, metal halide M is added and reacted at room temperature for 1-5 hours, preferably 3 hours; the reaction is carried out at room temperature for 3 hours, which can improve the separation yield and the purity of the final metallocene catalyst.

[0035] According to a specific embodiment of the present invention, preferably, the organolithium is selected from n-butyllithium and / or methyllithium; more preferably, the organolithium is n-butyllithium, and the metallocene catalyst prepared is a compound with the structure shown in Ti1-Ti4; the organolithium is methyllithium, and the metallocene catalyst prepared is a compound with the structure shown in Ti5-Ti8; the organolithium is further preferably a hexane solution of n-butyllithium and / or an ether solution of methyllithium.

[0036] According to a specific embodiment of the present invention, preferably, the chloride of Ti is selected from TiCl4·DME.

[0037] According to a specific embodiment of the present invention, preferably, n-butyllithium / methyllithium is added to the anhydrous diethyl ether solution of the ligand at a low temperature below -30°C to reduce the occurrence of side reactions. The resulting lithium salt can be used directly in the next synthesis without separation, which can improve the yield of the target product. Alternatively, the resulting lithium salt needs to be added to TiCl4·DME at a low temperature below -30°C and reacted at room temperature for 3 hours to improve the separation yield and the purity of the final titanium complex.

[0038] According to a specific embodiment of the present invention, preferably, after the reaction of compound L with organolithium and metal halide M is completed, post-treatment processes such as solvent washing and drying are also included. These are all conventional operations in the art and are not specifically limited here.

[0039] According to a specific embodiment of the present invention, preferably, the molar ratio of compound L, organolithium, and metal halide M is 1:(1-6):(1-2), more preferably 1:(2-5):(1.1-1.5), and even more preferably 1:(2.5-4.5):(1.2-1.4). Within the scope of the present invention, the conversion rate of the target product can be improved.

[0040] According to a specific embodiment of the present invention, preferably, the solvent is selected from one or a combination of two or more of tetrahydrofuran, anhydrous diethyl ether, toluene, and n-hexane.

[0041] According to a specific embodiment of the present invention, preferably, the source of compound L is not specifically limited. For example, compound L can be prepared by the following steps:

[0042] The compound L was prepared using the following steps:

[0043] Compound L was prepared by reacting N-substituted aniline with organolithium and compound A under a protective atmosphere;

[0044] The structure of compound A is as follows:

[0045] R in compound A 1 R 2 Respectively with R in equation (I) 1 R 2 same;

[0046] The structure of the N-substituted aniline is as follows:

[0047] R in N-substituted aniline 3 With R in equation (I) 3 same.

[0048] According to a specific embodiment of the present invention, preferably, under a protective atmosphere, organolithium is added to a solution of N-substituted aniline at -40°C to -78°C to react, and then a solution of compound A is slowly added dropwise at 0°C to -40°C to react, thereby obtaining compound L; more preferably, under a protective atmosphere, after adding organolithium to a solution of N-substituted aniline at -78°C to react, the mixture is cooled again to -60°C to -100°C and CO2 is bubbled in, and then a solution of compound A is slowly added dropwise at -20°C to react, thereby obtaining compound L. The slow dropwise addition of n-butyllithium to N-substituted aniline at -78°C can improve the conversion rate of the target product. Cooling the reaction solution again to -78°C and bubbling in CO2 after equilibrium can reduce the generation of byproducts.

[0049] According to a specific embodiment of the present invention, preferably, the molar ratio of compound A, organolithium, and N-substituted aniline is 1:(1.1-2.5):(1-2), more preferably 1:(1.5-2.0):(1.1-1.6).

[0050] According to a specific embodiment of the present invention, preferably, the reaction requires the addition of a solvent selected from at least one of DME, THF, n-hexane, anhydrous diethyl ether, toluene, etc.

[0051] According to a specific embodiment of the present invention, preferably, the source of compound A is not specifically limited. For example, compound A can be prepared by the following steps:

[0052] Compound A is prepared by reacting substituted or unsubstituted thiophene with dimethicone and polyphosphoric acid under a protective atmosphere; the structure of the substituted thiophene is as follows:

[0053] R in substituted thiophene 1 R 2 Respectively with R in equation (I) 1 R 2 same;

[0054] According to a specific embodiment of the present invention, preferably, the substituted or unsubstituted thiophene and dimethicone in the reaction are dissolved in dichloromethane and slowly added dropwise to polyphosphoric acid at 50°C with stirring for 2 hours, which can improve the conversion rate of the target product. Polyphosphoric acid is a conventional commercially available raw material.

[0055] According to a specific embodiment of the present invention, preferably, the molar ratio of the substituted or unsubstituted thiophene, dimethicone, and polyphosphoric acid is 1:(0.8-1.5):(4-15); more preferably, it is 1:(1-1.2):(5-10).

[0056] According to a specific embodiment of the present invention, preferably, the reaction formula for the preparation process of compound L is as follows:

[0057] Thirdly, the present invention also provides the application of the above-mentioned metallocene catalyst in the copolymerization reaction of ethylene and α-olefins.

[0058] According to a specific embodiment of the present invention, preferably, the copolymerization reaction temperature is 150-250°C, more preferably, the copolymerization reaction temperature is 160-220°C, wherein the catalytic activity for copolymerizing ethylene and 1-octene is highest at 200°C. It still exhibits very high copolymerization activity at 250°C.

[0059] According to a specific embodiment of the present invention, preferably, the pressure of ethylene introduced in the copolymerization reaction is 1-5 MPa, more preferably, the pressure of ethylene introduced in the copolymerization reaction is 1-3 MPa. When the catalytic copolymerization process is carried out in the range of 1-3 MPa, the performance of the obtained polyolefin elastomer is better, and the catalytic activity of catalytic copolymerization of ethylene and 1-octene is the highest at a pressure of 3 MPa.

[0060] According to a specific embodiment of the present invention, preferably, the copolymerization reaction time is 5-60 min, more preferably, the copolymerization reaction time is 5-15 min, wherein when the catalytic copolymerization process is carried out in the range of 5-15 min, the catalytic activity and the molecular weight of the copolymer are higher.

[0061] According to a specific embodiment of the present invention, preferably, the concentration of α-olefin is 0.5-10 mol / L based on the total volume of materials in the copolymerization reaction; more preferably, the concentration of α-olefin is 2-8 mol / L.

[0062] According to specific embodiments of the present invention, preferably, the α-olefin is selected from one or more combinations of 1-butene, 1-hexene, 1-octene, and 1-decene; more preferably, the α-olefin is selected from 1-hexene or 1-octene. Among these, the product exhibits the highest molecular weight and narrowest molecular weight distribution when ethylene and 1-octene are copolymerized using a metallocene catalyst.

[0063] According to a specific embodiment of the present invention, preferably, in the copolymerization reaction, metallocene catalyst and co-catalyst are used to catalyze the copolymerization of ethylene and α-olefin to obtain polyolefin elastomer.

[0064] According to a specific embodiment of the present invention, preferably, the co-catalyst is selected from one or more combinations of methylaluminoxane, modified methylaluminoxane, dry methylaluminoxane, tris(pentafluorophenyl)boron, and triphenylcarbontetra(pentafluorophenyl)boron salt, and the molar ratio of the metallocene catalyst to the co-catalyst is 1:(1-500); more preferably, the co-catalyst is dry methylaluminoxane and / or triphenylcarbontetra(pentafluorophenyl)boron salt, wherein the molar ratio of the metallocene catalyst to dry methylaluminoxane is 1:(100-300), and the molar ratio of the metallocene catalyst to triphenylcarbontetra(pentafluorophenyl)boron salt is 1:1.2. The copolymerization of ethylene and 1-octene using a mixed co-catalyst of dMAO and [Ph3C][B(C6F5)4] with the metallocene catalyst yields better results and higher activity.

[0065] According to a specific embodiment of the present invention, preferably, the solvent is selected from one or more combinations of n-hexane, n-heptane, n-octane, methylcyclohexane, isopentane, isohexane, isooctane, and isomeric saturated alkane mixtures (Isopar-E); more preferably, the solvent is selected from one or more combinations of n-hexane, n-heptane, and alkane mixtures. Among these, the metallocene catalyst exhibits the highest activity in catalyzing the copolymerization of 1-octene and ethylene, resulting in a high molecular weight product and a high α-olefin insertion rate.

[0066] According to a specific embodiment of the present invention, preferably, the weight-average molecular weight of the polyolefin elastomer is 52.1-597.4 kg / mol; the molecular weight distribution of the polyolefin elastomer is 1.85-2.62; and the α-olefin insertion rate of the polyolefin elastomer is 6.7 mol%-26.4 mol%.

[0067] The present invention has the following beneficial effects:

[0068] The metallocene catalyst of this invention employs a thiophene fused ring bridged with a rigid benzene ring. Through the steric hindrance effect of the substituents on the amine group, the steric hindrance effect on the fused ring, and the electronic effect, the high-temperature resistance and polymerization activity of the catalyst are improved. It can significantly enhance the solubility of the polymer in the solvent, reduce the viscosity of the solution system, prevent polymer precipitation and blockage of pipelines, and also facilitate the separation of subsequent products. The synthesis steps are simple, separation and purification are easy, the yield is high, greatly reduce the energy consumption of industrial production, and significantly improve economic benefits.

[0069] The polyolefin elastomer catalyst system composed of the metallocene catalyst and the co-catalyst of the present invention has significant temperature resistance and still has high catalytic activity at high temperatures. It is suitable for industrial production of high-temperature solution polymerization. The structure of the polymerization product can be controlled by changing the polymerization conditions, and polyolefin elastomers with high α-olefin insertion rate, high molecular weight and narrow distribution can be prepared. Attached Figure Description

[0070] Figure 1 is a single crystal structure diagram of the metallocene catalyst Ti8 provided in Example 15;

[0071] Figure 2 is the 1H NMR spectrum of the metallocene catalyst Ti8 provided in Example 15;

[0072] Figure 3 is the carbon NMR spectrum of the copolymer of ethylene and octene provided in Example 21;

[0073] Figure 4 is a structural diagram of the classic CGC catalyst Ti9 in Comparative Examples 1-4. Detailed Implementation

[0074] In order to provide a clearer understanding of the technical features, objectives and beneficial effects of the present invention, the technical solution of the present invention will now be described in detail below, but it should not be construed as limiting the scope of implementation of the present invention.

[0075] The structural formulas of compound A, compound L, and the metallocene catalyst in each embodiment are as follows:

[0076] Specifically:

[0077] Compound A1, R 1 For H, R 2 For H;

[0078] Compound A2, R 1 For Me, R 2 For Me;

[0079] Compound A3, R 1 For Me, R 2 For H;

[0080] Compound L1, R 1 For H, R 2 For H, R 3 For Cy;

[0081] Compound L2, R 1 For Me, R 2 For Me, R 3 For Cy;

[0082] Compound L3, R 1 For Me, R 2 For H, R 3 For Cy;

[0083] Compound L4, R 1 For Me, R 2 For Me, R 3 for t Bu;

[0084] Metallocene catalysts Ti1,R 1 For H, R 2 For H, R 3 For Cy, R 4 For Cl, R 5 For Cl;

[0085] Metallocene catalysts Ti2,R 1 For Me, R 2 For Me, R 3 For Cy, R 4 For Cl, R 5 For Cl;

[0086] Metallocene catalysts Ti3,R 1 For Me, R 2 For H, R 3 For Cy, R 4 For Cl, R 5 For Cl;

[0087] Metallocene catalysts Ti4,R 1 For Me, R 2 For Me, R 3 for t Bu, R 4 For Cl, R 5 For Cl;

[0088] Metallocene catalysts Ti5,R 1 For H, R 2 For H, R 3 For Cy, R 4 For Me, R 5 For Me;

[0089] Metallocene catalysts Ti6,R 1 For Me, R 2 For Me, R 3 For Cy, R 4 For Me, R 5 For Me;

[0090] Metallocene catalysts Ti7,R 1 For Me, R 2 For H, R 3 For Cy, R 4 For Me, R 5 For Me;

[0091] Metallocene catalyst Ti8,R 1 For Me, R 2 For Me, R 3 for t Bu, R 4 For Me, R5 For Me;

[0092] Metallocene catalyst Zr6,R 1 For Me, R 2 For Me, R 3 For Cy, R 4 For Me, R 5 For Me;

[0093] Metallocene catalyst Hf6,R 1 For Me, R 2 For Me, R 3 For Cy, R 4 For Me, R 5 For Me.

[0094] I. Catalyst Preparation

[0095] Example 1

[0096] This embodiment provides a compound A1, the synthesis method of which is as follows:

[0097] Thiophene (50.0 g, 0.60 mol) and dimethicone (59.5 g, 0.60 mol) were dissolved in 80 mL of dichloromethane and slowly added dropwise to polyphosphoric acid (1.217 kg, 3.6 mol) at 50 °C. The addition was completed in 2.5 hours, and the reaction was continued to be stirred at 50 °C for 2 hours. The reaction was terminated by adding 1 kg of ice. The mixture was extracted with methyl tert-butyl ether, washed with saturated sodium carbonate solution, dried with potassium carbonate, and the solvent was removed by evaporation. The mixture was then fractionally distilled to obtain compound A1 (89.3 g, 90%), which is a colorless oily liquid.

[0098] NMR characterization data of compound A1: 1 H NMR (400MHz, CDCl3): δ8.02(d,1H),7.18(d,1H),3.00(m,1H),2.74(m,1H),1.17(d,6H). 13 C NMR (400MHz, CDCl3): δ199.04,198.73,172.94,171.45,150.83,150.43,134.35,134.16,130.06,129 .83,55.70,50.20,40.71,35.31,18.86,15.93,15.89,15.16,15.08,11.95,11.80,11.54.Elemental analysis calculated for C9H 10OS:C,65.03;H,6.06;O,9.62;S,19.29;Found:C,67.23;H,6.77.

[0099] Example 2

[0100] This embodiment provides a compound A2, which differs from Example 1 only in that thiophene is replaced with 2,3-dimethylthiophene to obtain compound A2 in 70% yield.

[0101] NMR characterization data of compound A2: 1 H NMR (400MHz, CDCl3): δ3.00(m,1H),2.74(m,1H),2.35(s,3H),2.28(s,3H),1.15(d,6H). 13 C NMR (400MHz, CDCl3): δ199.04,198.73,172.94,171.45,150.83,150.43,134.35,134.16,130.06,129 .83,55.70,50.20,40.71,35.31,18.86,15.93,15.89,15.16,15.08,11.95,11.80,11.54.Elemental analysis calculated for C 11 H 14 OS: C, 68.00; H, 7.26; O, 8.23; S, 16.50; Found: C, 67.65; H, 7.37.

[0102] Example 3

[0103] This embodiment provides a compound A3, which differs from Example 1 only in that thiophene is replaced with 2-methylthiophene to obtain compound A3 with a yield of 94%.

[0104] NMR characterization data of compound A3: 1 H NMR (400MHz, CDCl3): δ6.86(s,1H),3.00(m,1H),2.74(m,1H),2.37(m,3H),1.16(d,6H). 13C NMR (400MHz, CDCl3): δ198.05,197.25,173.26,171.79,156.68,156.51,138.22,137.91,1 22.41,122.20,55.90,50.40,41.17,35.84,19.60,17.06,16.93,15.63,12.52.Elemental analysis calculated for C 10 H 12 OS: C, 66.63; H, 6.71; O, 8.88; S, 17.78; Found: C, 66.75; H, 6.89.

[0105] Example 4

[0106] This embodiment provides a compound L1, the synthesis method of which is as follows:

[0107] Under a nitrogen atmosphere, N-cyclohexylaniline (1.31 g, 7.51 mmol) was dissolved in 16 mL of anhydrous diethyl ether. 3.0 mL of n-butyllithium (7.5 mmol, 2.5 M solution in hexane) was slowly added dropwise at -78 °C. After stirring at -78 °C for 1 h, the reaction solution was brought to room temperature, a white solid precipitated, and butane gas was produced, which was purged using a bubbler. The reaction solution was cooled again to -78 °C, and after equilibrium was reached, CO2 was bubbled in, causing the white solid to disappear immediately. After stirring at -78 °C for 1 h, the temperature was slowly increased to -20 °C, and excess CO2 was purged using a bubbler, resulting in the precipitation of a white solid. Subsequently, tetrahydrofuran (0.60 g, 8.3 mmol) and 4.9 mL of tert-butyllithium (8.3 mmol, 1.7 M solution in pentane) were slowly added dropwise to the reaction system at -20 °C, and the reaction was stirred for 2 h. Reactant A1 (1.06 g, 6.38 mmol) was dissolved in 19 mL of anhydrous diethyl ether and added to the reaction system. The reaction mixture was stirred at -20 °C for 1 h, then slowly brought to room temperature. The reaction was stirred overnight, and 15 mL of water was added to terminate the reaction. The organic phase was collected, and the aqueous phase was extracted with ethyl acetate. The organic phases were combined, washed with aqueous HCl solution for two minutes, and then neutralized with saturated NaHCO3 solution. The organic phase was collected and dried over anhydrous magnesium sulfate. The solvent was removed by rotary evaporation to obtain an oily product, which was purified by silica gel column chromatography to give 2.30 g of the oily product, with a yield of 82%.

[0108] NMR characterization data of compound L1: 1H NMR (400MHz, CDCl3): δ7.59(s,1H),7.34(m,1H),7.23(m,1H),7.04(m,1H),7.02(s,1H),6.95(m, 1H),3.62(s,2H),3.56(m,1H),3.52(m,1H),1.79(s,3H),1.32(m,4H),1.28(m,6H),1.25(s,3H). 13 C NMR (400MHz, CDCl3): δ151.64,151.60,147.74,147.61,146.68,143.06,132.60,132.30,129.85,12 5.02,121.85,121.72,119.74,116.87,45.86,42.54,28.39,22.89,16.40,16.32,14.21.Elemental analysis calculated for C 21 H 26 ClNS:C,70.07;H,7.28;Cl,9.85;N,3.89;S,8.91;Found:C,69.95;H,7.43,N,4.01.

[0109] Example 5

[0110] This embodiment provides a compound L2, which differs from Example 4 only in that compound A1 is replaced with compound A2 to obtain compound L2 with a yield of 78%.

[0111] NMR characterization data of compound L2: 1 H NMR (400MHz, CDCl3): δ7.34(m,1H),7.23(m,1H),7.04(m,1H),6.95(m,1H),3.65(s,2H),3.58(m, 1H),3.51(m,1H),2.35(s,3H),2.28(s,3H),1.76(s,3H),1.33(m,4H),1.29(m,6H),1.23(s,3H). 13C NMR (400MHz, CDCl3): δ151.60,151.43,145.56,145.36,143.08,141.43,132.90,132.68,132.43,1 29.70,121.63,120.01,116.77,46.13,42.58,28.42,22.97,15.06,14.19,14.08,12.70.Elemental analysis calculated for C 23 H 30 ClNS:C,71.20;H,7.79;Cl,9.14;N,3.61;S,8.26;Found:C,71.02;H,7.91,N,3.88.

[0112] Example 6

[0113] This embodiment provides a compound L3, which differs from Example 4 only in that compound A1 is replaced with compound A3 to obtain compound L3 with a yield of 76%.

[0114] NMR characterization data of compound L3: 1 H NMR (400MHz, CDCl3): δ7.35(m,1H),7.26(m,1H),7.08(m,1H),6.95(m,1H),6.84(s,1H),3.61(s, 2H),3.56(m,1H),3.55(m,1H),2.37(s,3H),1.75(s,3H),1.33(m,4H),1.25(m,6H),1.20(s,3H). 13 C NMR (400MHz, CDCl3): δ151.60,151.43,145.56,145.36,143.08,141.43,132.90,132.68,132.43,1 29.70,121.63,120.01,116.77,46.13,42.58,28.42,22.97,15.06,14.19,14.08,12.70.Elemental analysis calculated for C 22 H 28 ClNS:C,70.66;H,7.55;Cl,9.48;N,3.75;S,8.57;Found:C,70.91;H,7.69,N,3.98.

[0115] Example 7

[0116] This embodiment provides a compound L4, which differs from Example 5 only in that the reactant N-cyclohexylaniline is replaced with N-tert-butylaniline to obtain compound L4 with a yield of 78%.

[0117] NMR characterization data of compound L4: 1 H NMR (400MHz, CDCl3): δ7.34(d,1H),7.23(m,1H),7.04(m,1H),6.95(m,1H),3.66(s, 2H),3.58(m,1H),2.35(s,3H),2.28(s,3H),1.76(s,3H),1.29(s,9H),1.23(s,3H). 13 C NMR (400MHz, CDCl3): δ151.60,151.43,145.56,145.36,143.08,141.43,132.90,132.68,132.4 3,129.70,121.63,120.01,116.77,46.13,42.58,28.42,22.97,15.06,14.08,12.70.Elemental analysis calculated for C 21 H 28 ClNS:C,69.68;H,7.80;Cl,9.79;N,3.87;S,8.86;Found:C,69.38;H,8.01,N,3.92.

[0118] Example 8

[0119] This embodiment provides a metallocene catalyst Ti1, the synthesis method of which is as follows.

[0120] Under a nitrogen atmosphere, compound L1 (0.13 g, 0.36 mmol) was dissolved in 2 mL of anhydrous diethyl ether, and 0.45 mL of n-butyllithium (0.72 mmol, 1.6 M in hexane) was slowly added dropwise at -30 °C. The mixture was stirred overnight at room temperature. The reaction solution was cooled again to -30 °C, and after equilibration, TiCl4·DME (0.070 g, 0.36 mmol) was added. The mixture was stirred at room temperature for 3 hours, and the solvent was removed by vacuum distillation. The product was extracted with a large amount of n-hexane, filtered, and the solvent was removed to obtain a gray solid (0.12 g, 72%).

[0121] NMR characterization data of Ti1 metallocene catalyst: 1H NMR (400MHz, CDCl3): δ7.47(s,1H),7.26(m,1H),7.17(m,1H),7.04(m,1H),7.02(s,1H), 6.96(m,1H),3.42(s,1H),1.68(s,3H),1.28(m,4H),1.23(m,6H),1.18(s,3H).Elemental analysis calculated for C 21 H 23 Cl2NSTi:C,57.29;H,5.27;Cl,16.10;N,3.18;S,7.28;Ti,10.87; Found:C,57.03;H,5.41,N,3.39.

[0122] Example 9

[0123] This embodiment provides a metallocene catalyst Ti2, which differs from Example 8 only in that compound L1 is replaced with L2, with a yield of 80%.

[0124] NMR characterization data of metallocene catalyst Ti2: 1 H NMR (400MHz, CDCl3): δ7.24(m,1H),7.20(m,1H),7.08(m,1H),6.92(m,1H),3.44(s,1H), 2.33(s,3H),2.20(s,3H),1.69(s,3H),1.30(m,4H),1.25(m,6H),1.21(s,3H).Elemental analysis calculated for C 23 H 27 Cl2NSTi:C,58.99;H,5.81;Cl,15.14;N,2.99;S,6.85;Ti,10.22; Found:C,58.78;H,6.05,N,3.18.

[0125] Example 10

[0126] This embodiment provides a metallocene catalyst Ti3, which differs from Example 8 only in that compound L1 is replaced with L3, with a yield of 82%.

[0127] NMR characterization data of Ti3 metallocene catalyst: 1H NMR (400MHz, CDCl3): δ7.28(m,1H),7.19(m,1H),6.96(m,1H),6.88(m,1H),6.75(s,1H), 3.46(s,1H),2.35(s,3H),1.52(s,3H),1.31(m,4H),1.20(m,6H),1.16(s,3H).Elemental analysis calculated for C 22 H 25 Cl2NSTi:C,58.17;H,5.55;Cl,15.61;N,3.08;S,7.06;Ti,10.54; Found:C,58.34;H,5.36,N,3.28.

[0128] Example 11

[0129] This embodiment provides a metallocene catalyst Ti4, which differs from Example 8 only in that compound L1 is replaced with L4, with a yield of 80%.

[0130] NMR characterization data of Ti4 metallocene catalyst: 1 H NMR (400MHz, CDCl3): δ7.35(m,1H),7.24(m,1H),7.05(m,1H),6.67(m,1H),3.99(s,3H),2.77(s,3H),2.56(s,3H),2.44(s,3H),1.86(s,9H).Elemental analysis calculated for C 21 H 25 Cl2NSTi:C,57.03;H,5.70;Cl,16.03;N,3.17;S,7.25;Ti,10.82;Found:C,56.92;H,5.96,N,3.38.

[0131] Example 12

[0132] This embodiment provides a metallocene catalyst Ti5.

[0133] Under a nitrogen atmosphere, compound L1 (0.13 g, 0.36 mmol) was dissolved in 2 mL of anhydrous diethyl ether. 0.89 mL of methyllithium (1.42 mmol, 1.6 M in diethyl ether) was slowly added dropwise at -30 °C, and the mixture was stirred overnight at room temperature. The reaction solution was cooled again to -30 °C, and after equilibration, TiCl4·DME (0.070 g, 0.36 mmol) was added. The mixture was stirred at room temperature for 3 hours, the solvent was removed by vacuum distillation, the product was extracted with a large amount of n-hexane, filtered, and the solvent was removed to give an orange-yellow solid (0.15 g, 76%).

[0134] NMR characterization data of Ti5 metallocene catalyst: 1 H NMR (400MHz, CDCl3):

[0135] δ7.38(s,1H),7.17(m,1H),7.06(m,1H),6.95(m,1H),6.90(s,1H),6.84(m,1H),3.31(s,1H) ,1.53(s,3H),1.25(m,4H),1.20(m,6H),1.16(s,3H),0.42(s,3H,TiMe),-0.10(s,3H,TiMe). 13 C NMR (400MHz, CDCl3): δ161.46,142.43,140.10,133.03,130.41,129.78,127.57,127.34,121.3 7,120.54,120.51,120.34,112.52,58.50,53.73,49.11,27.59,23.27,13.19,13.14.Elemental analysis calculated for C 23 H 29 NSTi:C,69.16;H,7.32;N,3.51;S,8.03;Ti,11.98;Found:C,69.03;H,7.55,N,3.68.

[0136] Example 13

[0137] This embodiment provides a metallocene catalyst Ti6, which differs from Example 12 only in that compound L1 is replaced with L2, with a yield of 78%.

[0138] NMR characterization data of Ti6 metallocene catalyst: 1H NMR (400MHz, CDCl3): δ7.18(m,1H),7.16(m,1H),7.02(m,1H),6.88(m,1H),3.40(s,1H),2.35(s,3H),2 .22(s,3H),1.65(s,3H),1.29(m,4H),1.26(m,6H),1.20(s,3H),0.44(s,3H,TiMe),-0.08(s,3H,TiMe). 13 C NMR (400MHz, CDCl3): δ161.58,141.36,138.41,137.20,132.96,129.70,127.53,127.39,126.87,121. 48,120.37,120.30,113.23,56.50,53.13,49.03,27.64,23.34,14.21,13.40,12.99,12.94.Elemental analysis calculated for C 25 H 33 NSTi:C,70.24;H,7.78;N,3.28;S,7.50;Ti,11.20;Found:C,70.05;H,7.99,N,3.06.

[0139] Example 14

[0140] This embodiment provides a metallocene catalyst Ti7, which differs from Example 12 only in that compound L1 is replaced with L3, with a yield of 73%.

[0141] NMR characterization data of Ti7 metallocene catalyst: 1 H NMR (400MHz, CDCl3): δ7.20(m,1H),7.11(m,1H),6.83(m,1H),6.79(m,1H),6.63(s,1H),3.42(s,1H),2 .29(s,3H),1.48(s,3H),1.26(m,4H),1.18(m,6H),1.10(s,3H),0.47(s,3H,TiMe),-0.10(s,3H,TiMe). 13C NMR (400MHz, CDCl3): δ159.83,159.52,145.93,144.90,140.78,139.93,139.21,138.86,135. 26,131.56,129.69,129.57,127.50,127.46,127.38,127.24,121.29,121.16,120.05,119.96, 118.90,118.74,117.99,117.74,113.87,110.38,57.91,55.31,54.87,51.68,50.27,50.12,3 4.77,27.58,27.27,23.10,22.05,20.31,19.90,16.66,14.70,13.11,12.98,12.68.Elemental analysis calculated for C 24 H 31 NSTi:C,69.72;H,7.56;N,3.39;S,7.75;Ti,11.58;Found:C,69.51;H,7.45,N,3.58.

[0142] Example 15

[0143] This embodiment provides a metallocene catalyst Ti8, which differs from Example 12 only in that compound L1 is replaced with L4, with a yield of 78%. The single crystal structure of Ti8 is shown in Figure 1, and its 1H NMR spectrum is shown in Figure 2.

[0144] NMR characterization data of Ti8 metallocene catalyst: 1 H NMR (400MHz, CDCl3): δ7.33(m,1H),7.21(m,1H),6.90(m,1H),6.42(m,1H),3.91(s,3H),2 .59(s,3H),2.42(s,3H),2.35(s,3H),1.78(s,9H),0.45(s,3H,TiMe),-0.07(s,3H,TiMe). 13 C NMR (400MHz, CDCl3): δ161.58,141.36,138.41,137.20,132.96,129.70,127.53,127.39,126.87,121. 48,120.37,120.30,113.23,56.50,53.13,49.03,27.64,23.34,14.21,13.40,12.99,12.94.Elemental analysis calculated for C23 H 31 NSTi:C,68.82;H,7.78;N,3.49;S,7.79;Ti,11.92;Found:C,69.05;H,8.01,N,3.63.

[0145] Example 55

[0146] This embodiment provides a metallocene catalyst Zr6, the synthesis method of which is as follows:

[0147] Under a nitrogen atmosphere, compound L2 (0.13 g, 0.36 mmol) was dissolved in 2 mL of anhydrous diethyl ether. 0.89 mL of methyllithium (1.42 mmol, 1.6 M in diethyl ether) was slowly added dropwise at -30 °C, and the mixture was stirred overnight at room temperature. The reaction solution was cooled again to -30 °C, and after equilibration, ZrCl4·DME (0.085 g, 0.36 mmol) was added. The mixture was stirred at room temperature for 3 hours, the solvent was removed by vacuum distillation, the product was extracted with a large amount of n-hexane, filtered, and the solvent was removed to give a grayish-white solid (77%).

[0148] NMR characterization data of metallocene catalyst Zr6: ¹H NMR (400 MHz, CDCl3): δ 7.14 (m, ¹H), 7.09 (m, ¹H), 6.91 (m, ¹H), 6.74 (m, ¹H), 3.26 (s, ¹H), 2.05 (s, ³H), 1.92 (s, ³H), 1.52 (s, ³H), 1.13 (m, ⁴H), 1.09 (m, ⁶H), 1.03 (s, ³H), 0.29 (s, ³H, ZrMe), -0.23 (s, ³H, ZrMe). Elemental analysis calculated for C 25 H 33 NSZr:C,64.81;H,6.98;N,14 2.74;S,7.11;Zr,20.44;Found:C,64.65;H,7.34,N,2.57.

[0149] Example 56

[0150] This embodiment provides a metallocene catalyst Hf6, the synthesis method of which is as follows:

[0151] Under a nitrogen atmosphere, compound L2 (0.13 g, 0.36 mmol) was dissolved in 2 mL of anhydrous diethyl ether. 0.89 mL of methyllithium (1.42 mmol, 1.6 M in diethyl ether) was slowly added dropwise at -30 °C, and the mixture was stirred overnight at room temperature. The reaction solution was cooled again to -30 °C, and after equilibration, HfCl4·DME (0.120 g, 0.36 mmol) was added. The mixture was stirred at room temperature for 3 hours, the solvent was removed by vacuum distillation, the product was extracted with a large amount of n-hexane, filtered, and the solvent was removed to give a yellow solid (78%).

[0152] NMR characterization data of metallocene catalyst Hf6: 1H NMR (400MHz, CDCl3): δ 7.08 (m, 1H), 7.05 (m, 1H), 6.84 (m, 1H), 6.71 (m, 1H), 3.18 (s, 1H), 2.01 (s, 3H), 1.86 (s, 3H), 1.47 (s, 3H), 1.01 (m, 4H), 0.97 (m, 6H), 0.94 (s, 3H), 0.21 (s, 3H, HfMe), -0.30 (s, 3H, HfMe). Elemental analysis calculated for C 25 H 33 NSHf:C,64.24;H,6.84;N,14 2.60;S,7.03;Hf,27.36;Found:C,64.01;H,7.29,N,2.49.

[0153] II. Olefin Polymerization

[0154] In the copolymerization reaction, under the combined action of a metallocene catalyst and a co-catalyst, ethylene and α-olefins are copolymerized to obtain polyolefin elastomers. The specific synthesis method is as follows:

[0155] The polymerization was carried out in a stainless steel high-temperature and high-pressure reactor equipped with a stirrer. Before the polymerization reaction, the reactor was vacuum-dried at 200°C for at least 2 hours. After the reactor cooled to room temperature, freshly distilled solvent, α-olefin, and co-catalyst were sequentially injected through the feed valve. Ethylene gas was introduced to 1.5 MPa, and the reaction system was heated to the set polymerization temperature. The mixture was stirred thoroughly, and a metallocene catalyst solution was added through the feed valve, maintaining the total volume of the polymerization system at 100 mL. The ethylene pressure was increased to the set polymerization pressure and maintained constant throughout the polymerization process. After the polymerization reaction reached the set time, the ethylene supply was stopped, the pressure was slowly released, the reactor was opened, and ethanol was added to terminate the reaction. The polymer product was obtained by filtration, soaked in hydrochloric acid / ethanol, filtered, washed several times with anhydrous ethanol, and then dried in a vacuum drying oven at 60°C to constant weight.

[0156] The polymerization activity was calculated using the final mass of the polyolefin, the amount of metallocene catalyst, and the polymerization time (activity = mass of polyolefin / (molar amount of metallocene catalyst × time)). The molecular weight and molecular weight distribution of the prepared polyolefin were determined by high-temperature gel permeation chromatography (HT-GPC) using 1,2,4-trichlorobenzene as solvent and mobile phase, concentration 1.5 g / L, flow rate 1 mL / min. A white solid product was obtained by vacuum removal of the solvent from a dried methylaluminoxane (dMAO) MAO solution. The α-olefin insertion rate of the copolymer was calculated using the polymer's proton NMR spectrum.

[0157] Example 16

[0158] Example 16 provides a copolymerization reaction of ethylene and α-olefins under the combined action of a metallocene catalyst and a co-catalyst. The reaction conditions are as follows: the metallocene catalyst Ti1 is 1 μmol; the molar ratio of co-catalyst MAO to metallocene catalyst Ti1 is 100:1; the molar ratio of co-catalyst [Ph3C][B(C6F5)4] to metallocene catalyst Ti1 is 1.2:1; the solvent is a mixture of isomeric saturated alkanes; the polymerization temperature is 200°C; the pressure of ethylene is 3 MPa; the concentration of 1-octene is 2.0 mol / L; and the polymerization time is 10 minutes.

[0159] The copolymerization of ethylene and α-olefins provided in Examples 17-23 differs from that in Example 16 only in that different metallocene catalysts are used to catalyze the copolymerization of ethylene and 1-octene. The specific reaction results are shown in Table 1. The carbon NMR spectrum of the copolymerized product of ethylene and octene provided in Example 21 is shown in Figure 3.

[0160] Table 1. Copolymerization of ethylene and 1-octene using different metallocene catalysts

[0161] Table 1 shows that the metallocene catalyst of this invention, which uses a thiophene fused ring to bridge a rigid benzene ring, can catalyze the copolymerization of ethylene and 1-octene with high activity at high temperatures through the synergistic effects of the steric hindrance of the substituents on the amine group, the steric hindrance of the cyclic ring, and electronic effects, yielding polyolefin elastomers with high monomer insertion rates. In comparison (Ti2 vs. Ti4, Ti6 vs. Ti8), the cyclohexyl-substituted catalyst exhibits higher polymerization activity and yields copolymers with higher molecular weights. Due to the lower steric hindrance of the cyclohexyl group, the α-olefin insertion rate of the polymer is higher at high temperatures, which is a result of the synergistic effect of the substituents on the cyclic ring and the steric hindrance of the amine group.

[0162] The copolymerization of ethylene and α-olefins provided in Examples 24-28 differs from that in Example 21 only in that the copolymerization reaction uses a metallocene catalyst Ti6 and different cocatalysts for the copolymerization of ethylene and 1-octene. The specific reaction results are shown in Table 2.

[0163] Table 2. Copolymerization of ethylene and 1-octene using different co-catalysts

[0164] Table 2 shows that in the copolymerization reaction, under the combined action of metallocene catalyst and co-catalyst, the copolymerization of ethylene and α-olefins can be carried out. The co-catalyst can be selected from one or more combinations of methylaluminoxane, modified methylaluminoxane, dry methylaluminoxane, tris(pentafluorophenyl)boron, and triphenylcarbontetra(pentafluorophenyl)boron salt. Among them, the co-catalyst of MAO and [Ph3C][B(C6F5)4] mixed with metallocene catalyst Ti6 has better effect and higher activity in the copolymerization of ethylene and 1-octene.

[0165] The copolymerization of ethylene and α-olefins provided in Examples 29-35 differs from that in Example 21 only in that, in the copolymerization reaction, metallocene catalyst Ti6 and different proportions of co-catalysts are used to copolymerize ethylene and 1-octene. The specific reaction results are shown in Table 3, where the Al / Ti molar ratio represents the molar ratio of MAO to metallocene catalyst Ti6, and the B / Ti molar ratio represents the molar ratio of [Ph3C][B(C6F5)4] to metallocene catalyst Ti6.

[0166] Table 3. Copolymerization of ethylene and 1-octene with different proportions of co-catalysts

[0167] Table 3 shows that in the copolymerization reaction, a molar ratio of MAO to Ti6 (50-500):1 provides highly active catalysis for the copolymerization of ethylene and 1-octene. The catalytic activity is highest when the molar ratio of MAO to Ti6 is in the range of (100-150):1, and reaches its peak at a ratio of 100:1. In the copolymerization reaction, a molar ratio of [Ph3C][B(C6F5)4] to Ti6 (1-1.5):1 provides highly active catalysis for the copolymerization of ethylene and 1-octene. The highest catalytic activity is observed when the molar ratio of [Ph3C][B(C6F5)4] to Ti6 is 1.2:1.

[0168] The only difference between the ethylene and α-olefin copolymerization provided in Examples 36-38 and Example 21 is that the metallocene catalyst Ti6 catalyzes the copolymerization of different α-olefin monomers with ethylene. The specific reaction results are shown in Table 4.

[0169] Table 4 Copolymerization of different α-olefin monomers with ethylene

[0170] Table 4 shows that the metallocene catalyst Ti6 can catalyze the copolymerization of different α-olefin monomers, including 1-butene, 1-hexene, 1-octene, and 1-decene, with ethylene at high temperatures. The copolymers have high molecular weight and high α-olefin insertion rate. Among them, the product with the highest molecular weight (569.8 kg / mol) and narrow molecular weight distribution and PDI (1.91) is produced by the copolymerization of ethylene and 1-octene catalyzed by the metallocene catalyst Ti6.

[0171] Examples 39-42 provide a method for preparing the polyolefin elastomer. Compared with Example 21, the only difference is that the copolymerization of ethylene and 1-octene is carried out in different solvents using the metallocene catalyst Ti6. The specific reaction conditions and polymerization results are shown in Table 5.

[0172] Table 5. Copolymerization of ethylene and 1-octene in different solvents

[0173] The results in Table 5 show that in different solvents, such as n-hexane, n-heptane, methylcyclohexane, isooctane, or mixtures of isomeric saturated alkanes, the metallocene catalyst Ti6 can be used to copolymerize ethylene and 1-octene. Among these, in the mixtures of isomeric saturated alkanes, the metallocene catalyst Ti6 exhibits the highest activity in catalyzing the copolymerization of 1-octene and ethylene, resulting in a high molecular weight product and a high α-olefin insertion rate.

[0174] The copolymerization of ethylene and α-olefins provided in Examples 43-46 differs from that in Example 21 only in that the copolymerization of ethylene and 1-octene is carried out at different temperatures using the metallocene catalyst Ti6. The specific reaction conditions and polymerization results are shown in Table 6.

[0175] Table 6. Copolymerization of ethylene and 1-octene at different temperatures

[0176] Table 6 shows that the metallocene catalyst Ti6 exhibits high catalytic activity for the copolymerization of ethylene and 1-octene at high temperatures of 150-250℃. The copolymerization process is carried out within a high temperature range of 160-220℃, resulting in polyolefin elastomers with superior performance. The highest catalytic activity for the copolymerization of ethylene and 1-octene is observed at 200℃. Very high copolymerization activity is still maintained at 250℃.

[0177] The copolymerization of ethylene and α-olefins provided in Examples 47-50 differs from that in Example 21 only in that the copolymerization of ethylene and 1-octene was carried out using a metallocene catalyst Ti6 under different pressures. The specific reaction conditions and polymerization results are shown in Table 7.

[0178] Table 7. Copolymerization of ethylene and 1-octene under different pressures.

[0179] The results in Table 7 show that the metallocene catalyst Ti6 can catalyze the copolymerization of ethylene and 1-octene with high activity under pressure of 1-5 MPa. When the catalytic copolymerization process is carried out in the range of 1-3 MPa, the polyolefin elastomers obtained have better performance. Among them, the catalytic activity for the copolymerization of ethylene and 1-octene is the highest at pressure of 3 MPa.

[0180] The copolymerization of ethylene and α-olefins provided in Examples 51-54 differs from that in Example 21 only in that the copolymerization of ethylene and 1-octene was carried out using a metallocene catalyst Ti6 at different polymerization times. The specific reaction conditions and polymerization results are shown in Table 8.

[0181] Table 8. Copolymerization of ethylene and 1-octene at different time points

[0182] The results in Table 8 show that the metallocene catalyst Ti6 can catalyze the copolymerization of ethylene and 1-octene with high activity in the range of 5-60 min. When the catalytic copolymerization process is carried out in the range of 5-15 min, the catalytic activity and the molecular weight of the copolymer are even higher.

[0183] Comparative Examples 1-4 provide examples of the copolymerization of ethylene and 1-octene catalyzed by the classic CGC catalyst Ti9. The structural formula of the CGC catalyst Ti9 is shown in Figure 4. The CGC titanium catalyst Ti9 was prepared according to the report in patent (WO2000075151) with a yield of 60%. Compared with the classic CGC catalyst Ti9, the metallocene catalyst Ti6 of this invention is simpler to synthesize and has a yield higher than 75%. The reaction conditions and results of the ethylene polymerization catalyzed by the metallocene catalyst Ti6 and the classic CGC catalyst Ti9 are shown in Table 9.

[0184] Table 9. Copolymerization of ethylene and 1-octene using metallocene catalyst Ti6 and classic CGC catalyst Ti9.

[0185] The results of Comparative Examples 1-4 and Examples 21, 43-45 show that the metallocene catalyst Ti6 has stronger thermal stability than the classic CGC catalyst Ti9. This is because the thiophene fused ring is bridged with the rigid benzene ring, and the high-temperature resistance and polymerization activity of the metallocene catalyst of the present invention are improved through the steric hindrance effect of the substituents on the amine group, the steric hindrance effect on the fused ring, and the electronic effect.

[0186] The copolymerization of ethylene and α-olefins provided in Examples 57-58 differs from that in Example 21 only in that different metallocene catalysts, Zr6 and Hf6, are used for the copolymerization of ethylene and 1-octene. The specific reaction conditions and polymerization results are shown in Table 10.

[0187] Table 10. Copolymerization of ethylene and 1-octene using different metallocene catalysts Ti6, Zr6, and Hf6

[0188] Table 10 shows that, compared with metallocene catalysts Zr6 and Hf6, the activity of metallocene catalyst Ti6 in catalyzing the copolymerization of ethylene and 1-octene is as high as 7.59 × 10⁻⁶. 7 g·mol -1 Ti·h -1 The polymer has a high molecular weight, a narrow molecular weight distribution, and a high 1-olefin insertion rate.

[0189] As can be seen from the above embodiments, the polyolefin elastomer provided by the present invention has an α-olefin insertion rate as high as 26.4 mol%, and the metallocene catalyst used in the solution polymerization process still exhibits high catalytic activity (6.58 × 10⁻⁶) at a high temperature of 220 °C. 7 g·mol -1 Ti·h -1 The polyolefin elastomer of the present invention has a high α-olefin insertion rate, high molecular weight, and narrow molecular weight distribution. At the same time, the high polymerization temperature significantly reduces the energy consumption of the reaction process, which is conducive to promoting the industrialization of polyolefin elastomers.

Claims

1. A metallocene catalyst, wherein, The metallocene catalyst has a structure as shown in formula (I): Among them, R 1 and R 2 Each is independently selected from H or an alkyl group having 1 to 20 carbon atoms, R 1 and R 2 Same or different; R 3 Selected from cyclohexyl (Cy) or tert-butyl (Tb) t Bu; R 4 and R 5 Each is independently selected from halogens or alkyl groups having 1 to 20 carbon atoms, R 4 and R 5 Same or different; M is selected from Ti, Zr, or Hf.

2. The metallocene catalyst according to claim 1, wherein, In equation (I), R 1 and R 2 Each is independently selected from H or Me; R 3 Selected from cyclohexyl (Cy) or tert-butyl (Tb) t Bu; R 4 and R 5 Each is independently selected from Me or Cl.

3. The metallocene catalyst according to claim 2, wherein, The metallocene catalyst is one of the compounds with the structures shown in the following formulas: Ti1-Ti8, Zr6, and Hf6.

4. A method for preparing a metallocene catalyst as described in any one of claims 1-3, wherein, Includes the following steps: Under a protective atmosphere, a metallocene catalyst with the structure shown in formula (I) was prepared by reacting compound L with organolithium and metal halide M. The structure of compound L is as follows: R in compound L 1 R 2 R 3 respectively with R in equation (I) 1 R 2 R 3 same.

5. The method for preparing the metallocene catalyst according to claim 4, wherein, The preparation method includes the following steps: Under a protective atmosphere, an organolithium compound was added to a solution containing compound L, and the reaction was carried out for 2-18 hours. Then, metal halide M is added, and the reaction is carried out for 1-5 hours to obtain the metallocene catalyst shown in formula (I).

6. The method for preparing the metallocene catalyst according to claim 4 or 5, wherein, The molar ratio of compound L, organolithium, and metal halide M is 1:(1-6):(1-2).

7. The method for preparing the metallocene catalyst according to claim 6, wherein, The molar ratio of compound L, organolithium, and metal halide M is 1:(2-5):(1.1-1.5).

8. The method for preparing the metallocene catalyst according to claim 4 or 5, wherein, The compound L was prepared using the following steps: Compound L was prepared by reacting N-substituted aniline with organolithium and compound A under a protective atmosphere; The structure of compound A is as follows: R in compound A 1 R 2 respectively with R in equation (I) 1 R 2 same; The structure of the N-substituted aniline is as follows: R in N-substituted aniline 3 With R in equation (I) 3 same.

9. The method for preparing the metallocene catalyst according to claim 8, wherein, The molar ratio of compound A, organolithium, and N-substituted aniline is 1:(1.1-2.5):(1-2).

10. The method for preparing the metallocene catalyst according to claim 9, wherein, The molar ratio of compound A, organolithium, and N-substituted aniline is 1:(1.5-2.0):(1.1-1.6).

11. The method for preparing the metallocene catalyst according to claim 8, wherein, Compound A was prepared using the following steps: Compound A is prepared by reacting substituted or unsubstituted thiophene with dimethacrylic acid and polyphosphoric acid under a protective atmosphere. The structure of the substituted thiophene is as follows: R in substituted thiophene 1 R 2 respectively with R in equation (I) 1 R 2 same.

12. The method for preparing the metallocene catalyst according to claim 11, wherein, The molar ratio of the substituted or unsubstituted thiophene, dimethicone, and polyphosphoric acid is 1:(0.8-1.5):(4-15).

13. The method for preparing the metallocene catalyst according to claim 12, wherein, The molar ratio of the substituted or unsubstituted thiophene, dimethicone, and polyphosphoric acid is 1:(1-1.2):(5-10).

14. The use of a metallocene catalyst as described in any one of claims 1-3 in the copolymerization reaction of ethylene and α-olefins.

15. The application according to claim 14, wherein, The copolymerization reaction temperature is 150-250℃; the concentration of α-olefin is 0.5-10 mol / L based on the total volume of materials in the copolymerization reaction; the pressure of ethylene introduced into the copolymerization reaction is 1-5 MPa; and the copolymerization reaction time is 5-60 min.

16. The application according to claim 15, wherein: The pressure of ethylene introduced in the copolymerization reaction is 1-3 MPa; the concentration of α-olefin is 2-8 mol / L based on the total volume of materials in the copolymerization reaction; the temperature of the copolymerization reaction is 160-220℃; and the time of the copolymerization reaction is 5-15 min.

17. The application according to claim 14, wherein, The α-olefin is selected from one or more combinations of 1-butene, 1-hexene, 1-octene, and 1-decene.

18. The application according to claim 14, wherein, The copolymerization reaction also uses a co-catalyst, which is selected from one or more of methylaluminoxane, modified methylaluminoxane, dry methylaluminoxane, tris(pentafluorophenyl)boron, and triphenylcarbontetra(pentafluorophenyl)boron salt; the molar ratio of the metallocene catalyst to the co-catalyst is 1:(1-500).

19. The application according to claim 14, wherein, The metallocene catalyst catalyzes the copolymerization reaction of ethylene and α-olefins to prepare polyolefin elastomers, wherein: The weight-average molecular weight of the polyolefin elastomer is 52.1-597.4 kg / mol.

20. The application according to claim 14, wherein, The metallocene catalyst catalyzes the copolymerization reaction of ethylene and α-olefins to prepare polyolefin elastomers, wherein: The molecular weight distribution of the polyolefin elastomer is 1.85-2.

62.

21. The application according to claim 14, wherein, The metallocene catalyst catalyzes the copolymerization reaction of ethylene and α-olefins to prepare polyolefin elastomers, wherein: The α-olefin insertion rate of the polyolefin elastomer is 6.7 mol% to 26.4 mol%.

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