A catalyst for copolymerization of ethylene with alpha-olefins, process for its preparation and use in polymerization

Abstract

The application discloses an olefin polymerization catalyst, which is suitable for copolymerization of ethylene and alpha-olefin. The pyridine amino and hydroxyl group of a ligand are complexed with a central metal, and it is found that the structure can significantly improve the conversion rate of alpha-olefin when used for copolymerization of ethylene and alpha-olefin, greatly reduces the use amount of alpha-olefin with high cost, thereby directly reducing the cost of POE, and by adjusting the structure and central metal of the catalyst, the spatial steric hindrance and central electron cloud density of the catalyst are changed, so that the catalyst can be used for preparing polyolefin products with high comonomer conversion rate, high polymerization activity, low melting point and ultrahigh molecular weight. The catalyst for copolymerization of ethylene and alpha-olefin has wide application prospect, and improves the competitiveness of the polyolefin product technology market in China.

Description

Technical Field

[0001] This invention relates to the field of catalysts, specifically to a catalyst for the copolymerization of ethylene and α-olefins, its preparation method, and its uses. Background Technology

[0002] Polyolefin materials are one of the pillar industries of modern polymer materials industry. Many excellent polyolefin products have good performance and unique properties in various aspects such as tear resistance, impact strength, tensile strength, and toughness. They have unique applications in all aspects of people's lives. Polyolefin catalysts play a vital role in olefin polymerization, so accelerating the research of polyolefin catalysts is particularly important.

[0003] In 1989, Dow reported a class of restrictive geometry catalysts in patent EP0416815B1. These catalysts had a high α-olefin insertion rate but low activity at high temperatures. They could not catalyze the reaction well under high temperature conditions and had poor thermal stability.

[0004] Patent CN116444579A proposes introducing an anthracene skeleton (structural formula shown below) into the structure of a salicylaldehyde imine catalyst. The catalyst is simple to prepare, has high activity, and is resistant to high temperatures, but the insertion rate is low and the polymer molecular weight is low, which cannot meet the needs of industry.

[0005]

[0006] Patent CN116284510A reports a structure in which the nitrogen atoms of cyclopentadiene and hydrazide are linked through carbon atoms (as shown in the formula below), which greatly increases the molecular weight of the polymer, but also has the problem of poor insertion rate, which cannot meet the production requirements.

[0007]

[0008] To address the aforementioned problems in the existing technology, there is a need in the field to further regulate the catalyst by controlling the type of metal at the catalyst center and the ligand structure, thereby improving the catalyst performance. Summary of the Invention

[0009] To address the above technical problems, this invention proposes an olefin polymerization catalyst (metal complex) with metal pyridine hydroxy complex as the core, its preparation method, and its applications.

[0010] The catalyst of this invention combines the amino and bridged hydroxyl groups of pyridine with the central metal atom, making the complex structure more stable. In addition, this structure has a certain degree of spatial rigidity, which can significantly improve the conversion rate of α-olefins and reduce the amount of α-olefins used while satisfying the requirement of high polymer molecular weight, thereby directly reducing the cost of POE.

[0011] When the catalyst of this invention is used to catalyze olefin polymerization, it can produce polyolefin products with high comonomer conversion, high polymerization activity, low melting point, and ultra-high molecular weight, and has broad application prospects.

[0012] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0013] A catalyst for the copolymerization of ethylene and α-olefins has the structure shown in Formula I:

[0014]

[0015] in,

[0016] R1 is independently selected from C1-C12 alkyl, C1-C6 alkylamino, preferably C1-C10 alkyl, C1-C4 alkylamino, and more preferably C1-C6 alkyl, C1-C2 alkylamino. For example, R1 is independently selected from methyl, isopropyl or tert-butyl, and cyclopropyl.

[0017] R2 is independently selected from C1-C24 alkyl, C6-C24 aryl, C3-C18 cycloalkyl, C5-C15 cycloalkenyl, and C1-C6 alkylamino. Preferably, in the catalyst shown in Formula I, R2 is independently selected from C1-C10 alkyl, C6-C16 aryl, C3-C12 cycloalkyl, C5-C10 cycloalkenyl, and C1-C4 alkylamino, wherein the C6-C24 aryl groups are optionally substituted with C1-C6 alkyl or C1-C6 alkoxy groups. For example, R2 is independently selected from methyl, isopropyl, tert-butyl, N,N-dimethyl, phenyl, chlorine, fluorine, or cyclopentadiene.

[0018] R3 is independently selected from C1-C12 alkyl, C1-C10 cycloalkyl, C1-C6 alkoxy, C6-C24 aryl, C1-C15 alkylamino, halogen-substituted. Preferably, in the catalysts of Formula I, R3 is independently selected from C1-C8 alkyl, C1-C6 cycloalkyl, C1-C4 alkoxy, C6-C16 aryl, C1-C12 alkylamino, chlorine, fluorine-substituted. For example, R3 is independently selected from methyl, isopropyl, tert-butyl, cyclopropane, phenyl, anthracene, methoxy, carbazole, chlorine, fluorine, or N,N-dimethyl.

[0019] M is selected from IVB metallic elements, preferably titanium, zirconium, or hafnium.

[0020] X is independently selected from halogen, C1-C8 alkyl, C1-C8 alkylamino or C5-C16 arylalkyl, more preferably, X is independently selected from halogen, C1-C6 alkyl, C1-C6 alkylamino or C5-C7 arylalkyl, for example, X is independently selected from methyl, chlorine, bromine, fluorine, dimethylamino, benzyl or (methylethyl)amino.

[0021] According to the catalyst of the present invention, the structure of the catalyst shown in Formula I is as follows:

[0022]

[0023] X and M are as defined above.

[0024] On the other hand, the present invention provides a method for preparing a catalyst for the copolymerization of ethylene and α-olefins, the method comprising the following steps:

[0025] In the presence of a dehydrogenating agent, the ligand compound shown in Formula II undergoes a complexation reaction with the metal salt MX4;

[0026]

[0027]

[0028] in,

[0029] R1 is independently selected from C1-C12 alkyl, C1-C6 alkylamino, preferably C1-C10 alkyl, C1-C4 alkylamino, and more preferably C1-C6 alkyl, C1-C2 alkylamino. For example, R1 is independently selected from methyl, isopropyl or tert-butyl, and cyclopropyl.

[0030] R2 is independently selected from C1-C24 alkyl, C6-C24 aryl, C3-C18 cycloalkyl, C5-C15 cycloalkenyl, and C1-C6 alkylamino. Preferably, in the catalyst shown in Formula II, R2 is independently selected from C1-C10 alkyl, C6-C16 aryl, C3-C12 cycloalkyl, C5-C10 cycloalkenyl, and C1-C4 alkylamino, wherein the C6-C24 aryl groups are optionally substituted with C1-C6 alkyl or C1-C6 alkoxy groups. For example, R2 is independently selected from methyl, isopropyl, tert-butyl, N,N-dimethyl, phenyl, chlorine, fluorine, or cyclopentadiene.

[0031] R3 is independently selected from C1-C12 alkyl, C1-C10 cycloalkyl, C1-C6 alkoxy, C6-C24 aryl, C1-C15 alkylamino, halogen-substituted. Preferably, in the catalysts of Formula II, R3 is independently selected from C1-C8 alkyl, C1-C6 cycloalkyl, C1-C4 alkoxy, C6-C16 aryl, C1-C12 alkylamino, chlorine, fluorine-substituted. For example, R3 is independently selected from methyl, isopropyl, tert-butyl, cyclopropane, phenyl, anthracene, methoxy, carbazole, chlorine, fluorine, or N,N-dimethyl.

[0032] M is selected from IVB metallic elements, preferably titanium, zirconium, or hafnium.

[0033] X is independently selected from halogen, C1-C8 alkyl, C1-C8 alkylamino or C5-C16 arylalkyl, preferably, X is independently selected from halogen, C1-C6 alkyl, C1-C6 alkylamino or C5-C7 arylalkyl, for example, X is independently selected from methyl, chlorine, bromine, fluorine, dimethylamino, benzyl or (methylethyl)amino.

[0034] According to the method for preparing the catalyst of the present invention, the metal salt MX4 is selected from titanium tetrachloride, zirconium tetrachloride, hafnium tetrachloride, tetrabenzyl hafnium, tetra(methylethyl)aminozirconium, titanium tetrabromide, zirconium tetrabromide or hafnium tetrabromide.

[0035] According to the method for preparing the catalyst of the present invention, the molar ratio of the ligand compound shown in Formula II to the metal salt MX4 is 1:(1.2-5); the molar ratio of the ligand compound shown in Formula II to the dehydrogenating agent is 1:(2-4).

[0036] According to the method for preparing the catalyst of the present invention, the dehydrogenating agent is one or more selected from alkyllithium, phenyllithium, potassium carbonate, sodium hydride, metallic sodium, and Grignard reagent, preferably n-butyllithium, methyllithium, and / or n-hexyllithium.

[0037] According to the method for preparing the catalyst of the present invention, the temperature of the complexation reaction is 0℃~70℃ and the time is 1h~6h.

[0038] According to the method for preparing the catalyst of the present invention, the ligand compound represented by formula II is prepared by the following reaction:

[0039]

[0040] R1, R2, and R3 are defined as above.

[0041] According to the method for preparing the catalyst of the present invention, the preparation step of the ligand compound represented by Formula II includes the following steps:

[0042] 1) Compound A is reacted with compound B in a solvent under weakly alkaline conditions by adding bis(triphenylphosphine)palladium dichloride and 4,5-bis(diphenylphosphine)-9,9-dimethyloxanthracene to generate compound C;

[0043] 2) Compound D reacts with Zn powder under strong acid conditions to produce compound E;

[0044] 3) Add bis(triphenylphosphine) nickel dichloride, dimethylphenylsilane, and sodium trimethylsilicate to compound C, and react with compound E in a solvent to generate compound F.

[0045] According to the method for preparing the catalyst of the present invention, in the step of preparing the ligand compound shown in Formula II,

[0046] In step 1), the reaction conditions are: reaction temperature of room temperature to 50°C, reaction time of 12 to 48W blue LED radiation for 12 to 48 hours;

[0047] In step 2), the strong acid is hydrochloric acid, and the reaction conditions are: reaction temperature room temperature to 60℃, reaction time 3 to 10 hours;

[0048] In step 3), the reaction conditions are: reaction temperature room temperature to 100℃, and reaction time 6 to 24 hours.

[0049] According to the method for preparing the catalyst of the present invention, in the step of preparing the ligand compound shown in Formula II,

[0050] In step 1), compound A is selected from one or more of 2-vinylpyridine, 4-methyl-2-vinylpyridine, 4-n-propyl-2-vinylpyridine, 4-isopropyl-2-vinylpyridine, 4-tert-butyl-2-vinylpyridine, 4-cyclopropane-2-vinylpyridine, 4-cyclobutane-2-vinylpyridine, 4-N,N-dimethyl-2-vinylpyridine, and 4-methoxy-2-vinylpyridine; the solvent is one or more of water, benzene, toluene, methanol, ethanol, isopropanol, tetrahydrofuran, and dimethylacetamide; and the weak base is dimethylamine or diethylamine.

[0051] In step 2), compound D is selected from one or more of 3-bromobenzaldehyde, 3-bromo-5-methylbenzaldehyde, 3-bromo-5-isopropylbenzaldehyde, 3-bromo-5-tert-butylbenzaldehyde, 3-bromo-5-cyclopropylbenzaldehyde, 3-bromo-5-phenylbenzaldehyde, 3-bromo-5-anthraylbenzaldehyde, and 3-bromo-5-carbazolebenzaldehyde, and the reaction solvent is one or more of water, ethanol, methanol, ethyl acetate, isopropanol, tetrahydrofuran, and dimethylacetamide;

[0052] The reaction solvent mentioned in step 3) is one or more of water, ethanol, methanol, ethyl acetate, isopropanol, tetrahydrofuran, and dimethylacetamide;

[0053] According to the method for preparing the catalyst of the present invention, in the step of preparing the ligand compound shown in Formula II,

[0054] In step 1), the molar ratio of compound A, compound B, bis(triphenylphosphine)-palladium dichloride, and 4,5-bis(diphenylphosphine)-9,9-dimethyloxane is 1:(1-2):(0.001-0.01):(0.001-0.01).

[0055] In step 2), the molar ratio of compound C to Zn powder is 1:(0.1 to 0.5).

[0056] In step 3), the molar ratio of compound C, compound D, bis(triphenylphosphine) nickel dichloride, dimethylphenylsilane, and sodium trimethylsilicate is 1:(2-4):(0.001-0.005):(2-6):(2-6).

[0057] Finally, the present invention provides a method for preparing polyolefins, the method comprising: polymerizing olefins in a solvent in the presence of the catalyst and co-catalyst described in the present invention to prepare polyolefin products.

[0058] According to the method for preparing polyolefins of the present invention, the concentration of the catalyst in the solvent is 0.1 to 10 μmol / L, preferably 2 to 5 μmol / L.

[0059] According to the method for preparing polyolefins of the present invention, the solvent used in the polymerization reaction is selected from one or more of alkanes, cycloalkanes, and aromatics, preferably toluene, heptane, hexane, Isopar E, and cyclohexane.

[0060] According to the method for preparing polyolefins of the present invention, the temperature of the polymerization reaction is 50-200°C, preferably 80-180°C; the polymerization reaction pressure is 0.1-10 MPa, preferably 2-5 MPa.

[0061] According to the method for preparing polyolefins of the present invention, the co-catalyst is an alkylaluminum and a borate.

[0062] According to the method for preparing polyolefins of the present invention, the alkylaluminum is selected from C1-C64. 10 Alkyl aluminum, aluminum oxane, or modified alkyl aluminum oxane, preferably triisobutylaluminum, trioctylaluminum, or octyl-modified methyl aluminum oxane, wherein the molar ratio of metal Al in the alkyl aluminum to metal M in the catalyst shown in Formula I is Al / M of (100-20000):1, preferably (100-500):1.

[0063] According to the method for preparing polyolefins of the present invention, the borate is selected from one or more of N,N-dimethylphenylamine tetra(pentafluorophenyl)borate, tripentafluorophenyl borate, triphenylmethyl tetra(pentafluorophenyl)borate, N,N-hexadecylaniline tetra(pentafluorophenyl)borate, and N,N-octadecylaniline tetra(pentafluorophenyl)borate, preferably N,N-hexadecylaniline tetra(pentafluorophenyl)borate and N,N-bisoctadecylaniline tetra(pentafluorophenyl)borate, wherein the molar ratio of element B in the borate to metal M in the catalyst shown in Formula I is B / M of (0-10):1, preferably (0-5):1.

[0064] According to the method for preparing polyolefins of the present invention, the olefin is selected from C2 to C12 olefins, preferably C2 to C8 α-olefins.

[0065] Compared with the prior art, the beneficial effects of the technical solution of the present invention are as follows:

[0066] The catalyst structure combines the amino and bridged hydroxyl groups of pyridine with the central metal atom, making the complex structure more stable. In addition, this structure has a certain degree of steric rigidity. While satisfying the requirement of high polymer molecular weight, the steric hindrance effect and the strength of the power supply capability of the ligand can be modified by introducing different substituents, thereby achieving the regulation of catalyst performance. Furthermore, this structure can significantly improve the conversion rate of α-olefins in the polymerization reaction and greatly reduce the amount of α-olefins used, thereby directly reducing the cost of POE.

[0067] The catalyst of this invention is used to catalyze olefin polymerization to prepare polyolefin products with excellent high α-olefin conversion, high activity, low melting point, and ultra-high molecular weight, and has broad application prospects. Detailed Implementation

[0068] The present invention will be further illustrated below with specific embodiments. These embodiments are merely illustrative and do not limit the scope of the invention.

[0069] The main materials and reagents used in the following examples are from the following sources:

[0070] 4-Isopropyl-2-vinylpyridine: AR, Aladdin

[0071] 4-tert-butyl-2-vinylpyridine: AR, Aladdin

[0072] 4-Cyclopropyl-2-vinylpyridine: AR, Aladdin

[0073] tert-butane bromide: AR, Aladdin

[0074] 5-Bromo-1,3-cyclopentadiene: AR, Aladdin

[0075] Dimethyl bromide: AR, Aladdin

[0076] 4-Bromotoluene: AR, Aladdin

[0077] Methyl bromide: AR, Aladdin

[0078] 3-Bromo-5-isopropylbenzaldehyde: AR, Innochem

[0079] 3-Bromo-5-tert-butylbenzaldehyde: AR, Innochem

[0080] 3-Bromo-5-phenylbenzaldehyde: AR, Innochem

[0081] 3-Bromo-5-N,N-dimethylbenzaldehyde: AR, Innochem

[0082] 3-Bromo-5-carbazolylbenzaldehyde: AR, Innochem

[0083] Bis(triphenylphosphine)palladium dichloride: AR, Aladdin

[0084] 4,5-Bis(diphenylphosphine)-9,9-dimethyloxanthracene: AR, Innochem

[0085] Bis(triphenylphosphine) nickel dichloride: AR, Aladdin

[0086] N,N-Dimethylacetamide: AR, Innochem

[0087] Dimethylphenylsilane: AR, Innochem

[0088] Sodium trimethylsilicate: AR, Innochem

[0089] Ethyl acetate: AR, Aldrich

[0090] Cyclohexane: AR, Aldrich

[0091] n-Hexane: AR, Aldrich

[0092] Zinc powder: AR, Innochem

[0093] Sodium chloride: AR, Aldrich

[0094] Potassium carbonate: AR, Aldrich

[0095] Dichloromethane: AR, Innochem

[0096] Petroleum ether: AR, Aldrich

[0097] Anhydrous sodium sulfate: AR, Innochem

[0098] Lithium n-hexylene: AR, Innochem

[0099] TiBr4: Tokyo Chemical Industry Co., Ltd.

[0100] ZrCl4: Tokyo Chemical Industry Co., Ltd.

[0101] HfBn4: Tokyo Chemical Industry Co., Ltd.

[0102] Tetra(methylethyl)aminozirconium: Tokyo Chemical Industry Co., Ltd.

[0103] Trioctyl aluminum: AR, Aladdin

[0104] N,N-Dioctadecylmethylamine tetra(pentafluorophenyl)borate: AR, Aladdin

[0105] Isopar E: ExxonMobil

[0106] tert-Butylaluminoxane (MAO): Albemarle

[0107] Ethylene: 99.9%, Beijing Yanshan Petrochemical Company

[0108] 1-Octenene: 98%, Beijing Yanshan Petrochemical Company

[0109] Unless otherwise specified, all other raw materials and reagents were obtained through commercially available channels.

[0110] Unless otherwise specified, the experimental methods used in the following examples are conventional methods.

[0111] The polymerization activity of the polymers described in the following examples was calculated according to the following formula: Polymer activity = polymer mass / (molar metal content in catalyst);

[0112] The weight-average molecular weight (Mw) of the polymer was obtained by testing with a PL-GPC220 at 160°C using three PLgel 10μm MIXED-B separation columns in series, with 1,2,4-trichlorobenzene as the solvent.

[0113] For the calculation method of α-olefin insertion rate, please refer to the reference (Macromolecules 1999, 32, 3817);

[0114] The α-olefin conversion rates of the polymers described in the following examples were calculated using the following formula:

[0115] α-Olefin conversion rate = (polymer mass × α-olefin insertion rate) / total α-olefin mass;

[0116] The melting points of the polymers were all determined using conventional DSC methods;

[0117] In all the following examples and comparative examples, the chemical reactions involved were carried out after nitrogen purging.

[0118] Example 1: Preparation of metal complex H1

[0119] The ligand and metal complex H1 were prepared according to the following combined route:

[0120]

[0121] (1) Pd(PPh3)2Cl2 (0.84 g, 1.2 mmol), 4,5-bis(diphenylphosphine)-9,9-dimethyloxanthracene (0.69 g, 1.2 mmol), and K2CO3 (33 g, 0.24 mol) were placed in a flask equipped with a stir bar. The flask was purged three times with argon gas. Under an argon atmosphere, 4-tert-butyl-2-vinylpyridine (32.2 g, 0.2 mol) and tert-butane bromide (41.1 g, 0.3 mol) were injected using a gas-tight syringe. DMA (200 mL) and water (3.6 mL) were injected into a flask. The reaction mixture was stirred for 36 h at room temperature under the radiation of a 36 W blue LED (about 3.0 cm away from the bulb). The mixture was quenched with a saturated NaCl aqueous solution. The organic phase was extracted with ethyl acetate (3 × 1 L). After filtration, the solvent was concentrated under vacuum at 50 m Bar to obtain the crude product of compound C1. The crude product was purified by silica gel column chromatography (petroleum ether: ethyl acetate = 10:1 (v / v)) to give compound C1 (35.2 g, 81%).

[0122] The NMR data of compound C1 are as follows: 1H NMR (500MHz, Chloroform) δ 8.57 (s, 1H), 7.45 (s, 1H), 7.34 (s, 1H), 6.39 (s, 1H), 6.27 (s, 1H), 1.32 (s, 9H), 1.00 (s, 9H).

[0123] (2) 3-bromo-5-tert-butylbenzaldehyde (48.2 g, 0.2 mol) and HCl (2 mol / L, 100 mL) were added to a 250 mL flask and stirred at room temperature. Zn powder (3.9 g, 60 mmol) was added and stirred at room temperature for 5 h. The product was extracted with diethyl ether, washed with saturated NaCl aqueous solution, dried with Na2SO4, and the solvent was concentrated under vacuum at 50 mBar to obtain the crude product of compound E1. The crude product was purified by thin-layer chromatography (cyclohexane: ethyl acetate = 3:1 (v / v)) to obtain compound E1 (40.7 g, 84%).

[0124] The NMR data of compound E1 are as follows: 1H NMR (500MHz, Chloroform) δ 7.50 (s, 2H), 7.24 (s, 2H), 7.03 (s, 2H), 5.45 (s, 2H), 1.88 (s, 2H), 1.27 (s, 18H).

[0125] (3) In a glove box, bis(triphenylphosphine) nickel dichloride (0.06 g, 0.1 mmol, 10 mol%), THF (250 mL), compound C1 (21.7 g, 0.1 mol), compound E1 (24.2 g, 0.05 mol), dimethylphenylsilane (78.8 g, 0.4 mol) and sodium trimethylsilicate (44.9 mg, 0.4 mol) were placed into a flask and reacted in an oil bath at 45 °C for 20 h. After the reaction was completed, the reaction mixture was diluted with dichloromethane and filtered through a SiO2 liner (cca.1 cm). The solvent was concentrated under vacuum at 50 mBar to obtain the crude product of compound F1. The crude product was purified by silica gel column chromatography (petroleum ether: ethyl acetate = 5:1 (v / v)) to obtain compound F1 (10.0 g, 26%).

[0126] The NMR data of compound F1 are as follows: ¹H NMR (500MHz, Chloroform) δ 8.55 (s, 2H), 7.62 (s, 2H), 7.25 (s, 2H), 6.97 (d, J = 15.0Hz, 4H), 6.76 (s, 2H), 5.48 (s, 2H), 3.80 (s, 2H), 2.12 (s, 2H), 2.09 (s, 2H), 2.03 (s, 2H), 1.31 (d, J = 5.0Hz, 36H), 0.91 (s, 18H).

[0127] (4) Anhydrous and oxygen-free operation was carried out in a glove box. Compound F1 (2.3 g, 3 mmol) was placed in a reaction flask, benzene (20 mL) was added and stirred to dissolve it. 1.6 M n-hexyllithium (3.0 mL, 4.8 mmol) was added dropwise. The temperature was set at 50 °C. ZrCl4 (0.8 g, 3.6 mmol) was added and the reaction was carried out for 1 h. After the reaction was completed, the mixture was filtered, the filtrate was dried under vacuum, and n-hexane was added for washing. The solid product was obtained by filtration and denoted as metal complex H1.

[0128]

[0129] Example 2: Preparation of metal complex H2

[0130] The ligand and metal complex H2 were prepared according to the following combined route:

[0131]

[0132] (1) Place Pd(PPh3)2Cl2 (1.4 g, 2 mmol), 4,5-bis(diphenylphosphine)-9,9-dimethyloxanthracene (1.2 g, 2 mmol), and K2CO3 (33 g, 0.24 mol) in a flask equipped with a stir bar. Purify the flask three times with argon gas. Under an argon atmosphere, use a gas-tight syringe to inject 4-cyclopropyl-2-vinylpyridine (29.0 g, 0.2 mol), 5-bromo-1,3-cyclopentadiene (43.5 g, 0.3 mol), and D... MA (200 mL) and water (3.6 mL) were injected into a flask. The reaction mixture was stirred for 15 h at 40 °C under the radiation of a 36 W blue LED (about 3.0 cm away from the bulb). The mixture was quenched with a saturated NaCl aqueous solution. The organic phase was extracted with ethyl acetate (3 × 1 L). After filtration, the solvent was concentrated under vacuum at 50 m Bar to obtain the crude product of compound C2. The crude product was purified by silica gel column chromatography (petroleum ether: ethyl acetate = 10:1 (v / v)) to give compound C2 (31.4 g, 75%).

[0133] The NMR data of compound C2 are as follows: ¹H NMR (500MHz, Chloroform) δ 8.57 (s, ¹H), 7.46 (s, ¹H), 7.34 (s, ¹H), 6.93 (s, ¹H), 6.65 (s, ¹H), 6.18 (s, 2H), 5.97 (s, 2H), 4.30 (s, ¹H), 1.81 (s, ¹H), 1.25 (s, 2H), 1.00 (s, 2H).

[0134] (2) 3-Bromo-5-phenylbenzaldehyde (48.2 g, 0.2 mol) and HCl (2 mol / L, 100 mL) were added to a 250 mL flask and stirred at 50 °C. Zn powder (6.5 g, 0.1 mol) was added and stirred at room temperature for 3 h. The product was extracted with diethyl ether, washed with saturated NaCl aqueous solution, dried with Na2SO4, and the solvent was concentrated under vacuum at 50 mBar to obtain the crude product of compound E2. The crude product was purified by thin-layer chromatography (cyclohexane: ethyl acetate = 3:1 (v / v)) to obtain compound E2 (33.4 g, 64%).

[0135] The NMR data for compound E2 are as follows: ¹H NMR (500 MHz, Chloroform) δ 7.84 (s, 2H), 7.75 (s, 4H), 7.54 (s, 2H), 7.49 (s, 4H), 7.43 (dd, J = 6.7, 3.1 Hz, 2H), 7.41 (d, J = 5.0 Hz, 2H), 5.48 (s, 2H), 2.02 (s, 2H).

[0136] (3) In a glove box, bis(triphenylphosphine) nickel dichloride (0.33 g, 0.5 mmol, 10 mol%), THF (250 mL), compound C2 (20.9 g, 0.1 mol), compound E2 (26.2 g, 0.05 mol), dimethylphenylsilane (78.8 g, 0.4 mol) and sodium trimethylsilicate (44.9 mg, 0.4 mol) were placed into a flask, the glass tube was tightened, and the flask was removed from the glove box. The reaction was carried out in an oil bath at 90 °C for 6 h. After the reaction was completed, the reaction mixture was diluted with dichloromethane and filtered through a SiO2 liner (cca.1 cm). The solvent was concentrated under vacuum at 50 mBar to obtain the crude product of compound F2. The crude product was purified by silica gel column chromatography (petroleum ether: ethyl acetate = 5:1 (v / v)) to obtain compound F2 (7.8 g, 20%).

[0137] The NMR data of compound F2 are as follows: ¹H NMR (500MHz, Chloroform) δ 8.55 (s, 2H), 7.77 (t, J = 12.5Hz, 8H), 7.62 (s, 2H), 7.49 (s, 4H), 7.41 (s, 2H), 7.25 (s, 2H), 7.06 (s, 2H), 6.14 (s, 4H), 5.67 (s, 4H), 5.52 (s, 2H), 3.61 (s, 2H), 3.52 (s, 2H), 2.04 (s, 2H), 1.91 (s, 4H), 1.62 (s, 2H), 1.25 (s, 4H), 1.00 (s, 4H).

[0138] (4) Anhydrous and oxygen-free operation was carried out in a glove box. Compound F2 (2.4 g, 3 mmol) was placed in a reaction flask, benzene (20 mL) was added and stirred to dissolve. 3.0 M n-hexyllithium (5.6 mL, 9 mmol) was slowly added dropwise. The temperature was set at 50 °C. ZrCl4 (1.4 g, 6 mmol) was added and the reaction was carried out for 3 h. After the reaction was completed, the mixture was filtered, the filtrate was dried, and n-hexane was added to wash the mixture. The solid product was obtained by filtration and was denoted as metal complex H2.

[0139]

[0140] Example 3: Preparation of metal complex H3

[0141] The ligand and metal complex H3 were prepared according to the following combined route:

[0142]

[0143] (1) Place Pd(PPh3)2Cl2 (1.4 g, 2 mmol), 4,5-bis(diphenylphosphine)-9,9-dimethyloxanthracene (1.2 g, 2 mmol), and K2CO3 (33 g, 0.24 mol) in a flask equipped with a stir bar. Purify the flask three times with argon gas. Under an argon atmosphere, use a gas-tight syringe to inject 4-tert-butyl-2-vinylpyridine (32.2 g, 0.2 mol), dimethylammonium bromide (24.8 g, 0.2 mol), and DMA. 200 mL of water and 3.6 mL of water were injected into a flask. The reaction mixture was stirred for 40 h at room temperature under the radiation of a 36 W blue LED (about 3.0 cm away from the bulb). The mixture was quenched with a saturated NaCl aqueous solution. The organic phase was extracted with ethyl acetate (3 × 1 L). The mixture was filtered and the solvent was concentrated under vacuum at 50 m Bar to obtain the crude product of compound C3. The crude product was purified by silica gel column chromatography (petroleum ether: ethyl acetate = 10:1 (v / v)) to obtain compound C3 (35.9 g, 88%).

[0144] The NMR data of compound C3 are as follows: 1H NMR (500MHz, Chloroform) δ 8.57 (s, 1H), 8.19 (s, 1H), 7.37 (s, 1H), 7.34 (s, 1H), 5.74 (s, 1H), 3.10 (s, 6H), 1.32 (s, 9H).

[0145] (2) 3-bromo-5-N,N-dimethylbenzaldehyde (45.6 g, 0.2 mol) and HCl (2 mol / L, 100 mL) were added to a 250 mL flask and stirred at room temperature. Zn powder (1.3 g, 0.02 mol) was added and stirred at room temperature for 10 h. The product was extracted with diethyl ether, washed with saturated NaCl aqueous solution, dried with Na2SO4, and the solvent was concentrated under vacuum at 50 mBar to obtain the crude product of compound E3. The crude product was purified by thin-layer chromatography (cyclohexane: ethyl acetate = 3:1 (v / v)) to obtain compound E3 (34.4 g, 75%).

[0146] The NMR data of compound E3 are as follows: 1H NMR (500MHz, Chloroform) δ 6.86 (s, 2H), 6.78 (s, 2H), 6.74 (s, 2H), 5.43 (s, 2H), 3.02 (s, 12H), 1.56 (s, 2H).

[0147] (3) In a glove box, bis(triphenylphosphine) nickel dichloride (0.33 g, 0.5 mmol, 10 mol%), THF (250 mL), compound C3 (20.4 g, 0.1 mol), compound E3 (11.5 g, 0.025 mol), dimethylphenylsilane (78.8 g, 0.4 mol) and sodium trimethylsilicate (44.9 mg, 0.4 mol) were placed into a flask, the glass tube was tightened, and the flask was removed from the glove box. The reaction was carried out at room temperature for 24 h. After the reaction was completed, the reaction mixture was diluted with dichloromethane and filtered through a SiO2 liner (cca.1 cm). The solvent was concentrated under vacuum at 50 mBar to obtain the crude product of compound F3. The crude product was purified by silica gel column chromatography (petroleum ether: ethyl acetate = 5:1 (v / v)) to obtain compound F3 (3.2 g, 18%).

[0148] The NMR data of compound F3 are as follows: ¹H NMR (500MHz, Chloroform) δ 8.55 (s, 2H), 7.62 (s, 2H), 7.25 (s, 2H), 6.80 (d, J = 15.0Hz, 4H), 6.30 (s, 2H), 5.40 (s, 2H), 4.06 (s, 2H), 3.27 (s, 2H), 3.02 (s, 12H), 2.98 (s, 2H), 2.25 (s, 12H), 1.32 (s, 18H), 1.26 (s, 2H).

[0149] (4) Anhydrous and oxygen-free operation was carried out in a glove box. Compound F3 (2.1 g, 3 mmol) was placed in a reaction flask, benzene (20 mL) was added and stirred to dissolve. Potassium carbonate (55.2 g, 0.4 mol) was slowly added dropwise. The temperature was set to 0℃. Tetrabenzylhafnium (8.1 g, 15 mmol) was added and the reaction was carried out for 6 h. After the reaction was completed, the mixture was filtered, the filtrate was dried, and hexane was added to wash the mixture. The solid product was obtained by filtration and was denoted as metal complex E4.

[0150]

[0151] Example 4: Preparation of metal complex H4

[0152] The ligand and metal complex H4 were prepared according to the following combined route:

[0153]

[0154] (1) Place Pd(PPh3)2Cl2 (0.7g, 1mmol), 4,5-bis(diphenylphosphine)-9,9-dimethyloxanthracene (0.6g, 1mmol), and K2CO3 (33g, 0.24mol) in a flask equipped with a stir bar. Purge the flask three times with argon gas. Under an argon atmosphere, use a gas-tight syringe to inject 4-isopropyl-2-vinylpyridine (29.4g, 0.2mol), 4-bromotoluene (51.3g, 0.3mol), and DMA ( 200 mL of water and 3.6 mL of water were injected into a flask. The reaction mixture was stirred for 30 h at 35 °C under the radiation of a 36 W blue LED (about 3.0 cm away from the bulb). The mixture was quenched with a saturated NaCl aqueous solution. The organic phase was extracted with ethyl acetate (3 × 1 L). The mixture was filtered and the solvent was concentrated under vacuum at 50 m Bar to obtain the crude product of compound C4. The crude product was purified by silica gel column chromatography (petroleum ether: ethyl acetate = 10:1 (v / v)) to obtain compound C4 (37.9 g, 80%).

[0155] The NMR data of compound C4 are as follows: ¹H NMR (500MHz, Chloroform) δ 8.57 (s, ¹H), 7.59 (s, 2H), 7.56 (s, ¹H), 7.49 (s, ¹H), 7.39 (s, 2H), 7.34 (s, ¹H), 6.75 (s, ¹H), 2.87 (s, ¹H), 2.41 (s, 3H), 1.20 (s, 6H).

[0156] (2) 3-bromo-5-isopropylbenzaldehyde (45.4 g, 0.2 mol) and HCl (2 mol / L, 100 mL) were added to a 250 mL flask and stirred at room temperature. Zn powder (2.6 g, 0.04 mol) was added and stirred at 40 °C for 4 h. The product was extracted with diethyl ether, washed with saturated NaCl aqueous solution, dried with Na2SO4, and the solvent was concentrated under vacuum at 50 mBar to obtain the crude product of compound E4. The crude product was purified by thin-layer chromatography (cyclohexane: ethyl acetate = 3:1 (v / v)) to obtain compound E4 (32.4 g, 71%).

[0157] The NMR data of compound E4 are as follows: 1H NMR (500MHz, Chloroform) δ 7.44 (s, 2H), 7.33 (s, 2H), 7.03 (s, 2H), 5.44 (s, 2H), 2.87 (s, 2H), 1.92 (s, 2H), 1.20 (s, 12H).

[0158] (3) In a glove box, bis(triphenylphosphine) nickel dichloride (0.13 g, 0.2 mmol, 10 mol%), THF (250 mL), compound C4 (23.7 g, 0.1 mol), compound E4 (22.8 g, 0.05 mol), dimethylphenylsilane (78.8 g, 0.4 mol) and sodium trimethylsilicate (44.9 mg, 0.4 mol) were placed into a flask, the glass tube was tightened and the flask was removed from the glove box. The reaction was carried out at 70 °C for 10 h. After the reaction was completed, the reaction mixture was diluted with dichloromethane and filtered through a SiO2 liner (cca.1 cm). The solvent was concentrated under vacuum at 50 mBar to obtain the crude product of compound F4. The crude product was purified by silica gel column chromatography (petroleum ether: ethyl acetate = 5:1 (v / v)) to obtain compound F4 (9.7 g, 25%).

[0159] The NMR data of compound F4 are as follows: ¹H NMR (500MHz, Chloroform) δ 8.55 (s, 2H), 7.62 (s, 2H), 7.25 (s, 2H), 7.06 (s, 4H), 7.00 (s, 6H), 6.97 (s, 2H), 6.86 (s, 2H), 5.43 (s, 2H), 4.02 (s, 2H), 3.40 (s, 2H), 3.11 (s, 2H), 2.87 (s, 4H), 2.19 (s, 6H), 1.37 (s, 2H), 1.20 (s, 24H).

[0160] (4) Perform anhydrous and oxygen-free operation in a glove box. Place compound F4 (2.3g, 3mmol) in a reaction flask, add benzene (20mL) and stir to dissolve. Slowly add sodium metal (0.3g, 12mmol), set the temperature to 55℃, add titanium tetrabromide (4.4g, 12mmol), and react for 2h. After the reaction is complete, filter, dry the filtrate, add n-hexane to wash, and filter to obtain a solid product, which is denoted as metal complex H4.

[0161]

[0162] Example 5: Preparation of metal complex H5

[0163] The ligand and metal complex H5 were prepared according to the following combined route:

[0164]

[0165] (1) Place Pd(PPh3)2Cl2 (0.7g, 1mmol), 4,5-bis(diphenylphosphine)-9,9-dimethyloxanthracene (0.6g, 1mmol), and K2CO3 (33g, 0.24mol) in a flask equipped with a stir bar. Purify the flask three times with argon gas. Under an argon atmosphere, use a gas-tight syringe to inject 4-fluoro-2-vinylpyridine (24.6g, 0.2mol), 2-bromopropane (36.9g, 0.3mol), and DMA (2... 0.0 mL of water and 3.6 mL of water were injected into a flask. The reaction mixture was stirred for 30 h at 30 °C under the radiation of a 36 W blue LED (about 3.0 cm away from the bulb). The mixture was quenched with a saturated NaCl aqueous solution. The organic phase was extracted with ethyl acetate (3 × 1 L). After filtration, the solvent was concentrated under vacuum at 50 m Bar to obtain the crude product of compound C5. The crude product was purified by silica gel column chromatography (petroleum ether: ethyl acetate = 10:1 (v / v)) to obtain compound C5 (22.8 g, 83%).

[0166] The NMR data of compound C5 are as follows: 1H NMR (500MHz, Chloroform) δ 8.54 (s, 1H), 7.28 (s, 1H), 7.02 (s, 1H), 6.83 (s, 1H), 6.72 (s, 1H), 1.63 (s, 3H).

[0167] (2) 3-bromo-5-fluoro-benzaldehyde (40.6 g, 0.2 mol) and HCl (2 mol / L, 100 mL) were added to a 250 mL flask and stirred at room temperature. Zn powder (2.6 g, 0.04 mol) was added and stirred at 40 °C for 4 h. The product was extracted with diethyl ether, washed with saturated NaCl aqueous solution, dried with Na2SO4, and the solvent was concentrated under vacuum at 50 mBar to obtain the crude product of compound E5. The crude product was purified by thin-layer chromatography (cyclohexane: ethyl acetate = 3:1 (v / v)) to obtain compound E5 (24.5 g, 60%).

[0168] The NMR data of compound E5 are as follows: 1H NMR (500MHz, Chloroform) δ 7.35 (s, 2H), 7.21 (s, 2H), 7.12 (s, 2H), 5.42 (s, 2H), 1.25 (s, 2H).

[0169] (3) In a glove box, bis(triphenylphosphine) nickel dichloride (0.13 g, 0.2 mmol, 10 mol%), THF (250 mL), compound C5 (13.7 g, 0.1 mol), compound E5 (20.4 g, 0.05 mol), dimethylphenylsilane (78.8 g, 0.4 mol) and sodium trimethylsilicate (44.9 mg, 0.4 mol) were placed into a flask, the glass tube was tightened and the flask was removed from the glove box. The reaction was carried out at 50 °C for 15 h. After the reaction was completed, the reaction mixture was diluted with dichloromethane and filtered through a SiO2 liner (cca.1 cm). The solvent was concentrated under vacuum at 50 mBar to obtain the crude product of compound F5. The crude product was purified by silica gel column chromatography (petroleum ether: ethyl acetate = 5:1 (v / v)) to obtain compound F5 (5.2 g, 12%).

[0170] The NMR data of compound F5 are as follows: ¹H NMR (500MHz, Chloroform) δ 8.51 (s, 2H), 7.38 (s, 2H), 7.10 (s, 2H), 7.09 (s, 2H), 7.03 (s, 2H), 6.72 (s, 2H), 5.40 (s, 2H), 3.59 (s, 2H), 1.84 (s, 2H), 1.73 (s, 2H), 1.59 (s, 2H), 1.29 (s, 2H), 0.91 (s, 12H).

[0171] (4) Anhydrous and oxygen-free operation was carried out in a glove box. Compound F5 (2.5 g, 3 mmol) was placed in a reaction flask, benzene (20 mL) was added and stirred to dissolve it. 1.6 M methyl lithium (3.0 mL, 4.8 mmol) was slowly added dropwise. The temperature was set at 60 °C. Tetra(methylethylamino)zirconium (1.9 g, 6 mmol) was added and the reaction was carried out for 1.5 h. After the reaction was completed, the mixture was filtered, the filtrate was dried under vacuum, and hexane was added to wash the mixture. The solid product was obtained by filtration and was denoted as metal complex H5.

[0172]

[0173] Comparative Example 1: Preparation of Metal Complex H6

[0174] The catalyst H6, as shown in Example 2 of patent CN114316101A, was prepared using the method described in the following formula.

[0175]

[0176] Comparative Example 2: Preparation of Metal Complex H7

[0177] The catalyst H7, as shown in Example 2 of patent CN116284510A, was prepared using the method described in the following formula.

[0178]

[0179] Preparation Example: Preparation of Polyolefins

[0180] The metal complexes prepared in Examples 1-5 and Comparative Examples 1-2 were used to carry out ethylene / 1-hexene copolymerization reactions according to the following methods and the raw materials and parameters shown in Table 1, respectively, to prepare the corresponding polyolefin products:

[0181] The high-pressure reactor was set at 150℃ and dried for 3 hours. Vacuum was then applied and the temperature gradually decreased to 25℃. 320 mL of Isopar E, 80 mL of 1-octene, trioctylaluminum, and N,N-bis(octadecylmethylamine)tetra(pentafluorophenyl)borate were added sequentially. The molar ratio of trioctylaluminum to the main catalyst metal element is denoted as Al / M, and the molar ratio of element B in N,N-bis(octadecylmethylamine)tetra(pentafluorophenyl)borate to element M in the main catalyst is denoted as B / M. The amounts of trioctylaluminum and N,N-bis(octadecylmethylamine)tetra(pentafluorophenyl)borate added are shown in Table 1. The temperature was raised to 80-180℃, and ethylene monomer was introduced at 2-5 MPa. The main catalyst was then added to initiate the polymerization reaction. Throughout the polymerization, the stirring rate, polymerization temperature, and ethylene pressure remained constant. The reaction time was 5 minutes. After the reaction, the gas in the reactor was vented, the reaction liquid was neutralized, and the polymer precipitate was obtained. This precipitate was washed several times and dried to obtain the polyolefin product.

[0182] Table 1. Reaction conditions for each embodiment and comparative example.

[0183]

[0184] Performance testing of polyolefins (test example)

[0185] The polyolefin products prepared in each embodiment and comparative example were subjected to the performance tests shown in Table 2 below, and the results are as follows:

[0186] Table 2 Performance Test Results

[0187]

[0188] The above examples and comparative data show that the catalyst of the present invention has excellent catalytic performance. When applied to the copolymerization of olefins / 1-octene, it can significantly improve the conversion rate of 1-octene. The polyolefin products prepared by the catalyst of the present invention have high α-olefin conversion rate, high activity, low melting point, and ultra-high molecular weight.

[0189] The above description is only a preferred embodiment of the present invention. It should be noted that those skilled in the art can make several improvements and additions without departing from the method of the present invention, and these improvements and additions should also be considered within the scope of protection of the present invention.

Claims

1. A catalyst for the copolymerization of ethylene and α-olefins, having the structure shown in Formula I: in, R1 is independently selected from C1-C12 alkyl, C1-C6 alkylamino, preferably C1-C10 alkyl, C1-C4 alkylamino, and more preferably C1-C6 alkyl, C1-C2 alkylamino. For example, R1 is independently selected from methyl, isopropyl or tert-butyl, and cyclopropyl. R2 is independently selected from C1-C24 alkyl, C6-C24 aryl, C3-C18 cycloalkyl, C5-C15 cycloalkenyl, and C1-C6 alkylamino. Preferably, in the catalyst shown in Formula I, R2 is independently selected from C1-C10 alkyl, C6-C16 aryl, C3-C12 cycloalkyl, C5-C10 cycloalkenyl, and C1-C4 alkylamino, wherein the C6-C24 aryl groups are optionally substituted with C1-C6 alkyl or C1-C6 alkoxy groups. For example, R2 is independently selected from methyl, isopropyl, tert-butyl, N,N-dimethyl, phenyl, chlorine, fluorine, or cyclopentadiene. R3 is independently selected from C1-C12 alkyl, C1-C10 cycloalkyl, C1-C6 alkoxy, C6-C24 aryl, C1-C15 alkylamino, halogen-substituted. Preferably, in the catalysts of Formula I, R3 is independently selected from C1-C8 alkyl, C1-C6 cycloalkyl, C1-C4 alkoxy, C6-C16 aryl, C1-C12 alkylamino, chlorine, fluorine-substituted. For example, R3 is independently selected from methyl, isopropyl, tert-butyl, cyclopropane, phenyl, anthracene, methoxy, carbazole, chlorine, fluorine, or N,N-dimethyl. M is selected from IVB metallic elements, preferably titanium, zirconium, or hafnium. X is independently selected from halogen, C1-C8 alkyl, C1-C8 alkylamino or C5-C16 arylalkyl, more preferably, X is independently selected from halogen, C1-C6 alkyl, C1-C6 alkylamino or C5-C7 arylalkyl, for example, X is independently selected from methyl, chlorine, bromine, fluorine, dimethylamino, benzyl or (methylethyl)amino.

2. The catalyst according to claim 1, characterized in that, The structure of the catalyst shown in Formula I is as follows:

3. The method for preparing the catalyst for copolymerization of ethylene and α-olefins as described in claim 1 or 2, wherein the method comprises the following steps: In the presence of a dehydrogenating agent, the ligand compound shown in Formula II undergoes a complexation reaction with the metal salt MX4; 4. The preparation method according to claim 3, characterized in that, The metal salt MX4 is selected from titanium tetrachloride, zirconium tetrachloride, hafnium tetrachloride, tetrabenzylhafnium, tetra(methylethyl)aminozirconium, titanium tetrabromide, zirconium tetrabromide, or hafnium tetrabromide; and / or, the molar ratio of the ligand compound shown in Formula II to the metal salt MX4 is 1:(1.2-5); the molar ratio of the ligand compound shown in Formula II to the dehydrogenating agent is 1:(2-4); and / or, the dehydrogenating agent is one or more of alkyllithium, phenyllithium, potassium carbonate, sodium hydride, metallic sodium, and Grignard reagents, preferably n-butyllithium, methyllithium, and / or n-hexyllithium; and / or, the temperature of the complexation reaction is 0℃-70℃, and the time is 1h-6h.

5. A method for preparing a polyolefin, the method comprising: The olefins are polymerized in a solvent in the presence of a catalyst and a co-catalyst to prepare a polyolefin product. The catalyst is selected from the ethylene-α-olefin copolymerization catalyst as described in claim 1 or 2, or the ethylene-α-olefin copolymerization catalyst prepared by the preparation method as described in claim 3 or 4.

6. The preparation method according to claim 5, characterized in that, The concentration of the catalyst in the solvent is 0.1–10 μmol / L, preferably 2–5 μmol / L; and / or, the solvent used in the polymerization reaction is selected from one or more of alkanes, cycloalkanes, and aromatics, preferably toluene, heptane, hexane, Isopar E, or cyclohexane.

7. The preparation method according to claim 5 or 6, characterized in that, The polymerization reaction temperature is 50–200°C, preferably 80–180°C; the polymerization reaction pressure is 0.1–10 MPa, preferably 2–5 MPa.

8. The preparation method according to any one of claims 5-7, characterized in that, The cocatalyst is an alkylaluminum and a borate; the alkylaluminum is selected from C1-C6. 10 Alkyl aluminum, aluminum oxane, or modified alkyl aluminum oxane, preferably triisobutylaluminum, trioctylaluminum, or octyl-modified methyl aluminum oxane, wherein the molar ratio of metal Al in the alkyl aluminum to metal M in the catalyst shown in Formula I is Al / M of (100-20000):1, preferably (100-500):

1.

9. The preparation method according to claim 8, characterized in that, The borate is selected from one or more of N,N-dimethylphenylammonium tetra(pentafluorophenyl)borate, tripentafluorophenyl borate, triphenylmethyl tetra(pentafluorophenyl)borate, N,N-hexadecylaniline tetra(pentafluorophenyl)borate, and N,N-octadecylaniline tetra(pentafluorophenyl)borate, preferably N,N-hexadecylaniline tetra(pentafluorophenyl)borate and N,N-bisoctadecylaniline tetra(pentafluorophenyl)borate, wherein the molar ratio of element B in the borate to metal M in the catalyst shown in Formula I is B / M of (0-10):1, preferably (0-5):

1.

10. The preparation method according to any one of claims 5-9, characterized in that, The olefin is selected from C2 to C12 olefins, preferably C2 to C8 α-olefins.

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