A metallocene catalyst, a method for preparing the same, and use thereof

Abstract

The application provides a metallocene catalyst and a preparation method and application thereof, the metallocene catalyst has a structure as shown in formula (1): the nitrogen of hydrazine is connected with cyclopentadiene in the catalyst structure through a carbon atom, so that the complex structure is more stable, and the nitroxide and the metal are coordinated, compared with a traditional phenolic hydroxyl group, the change of bond length makes the catalyst have a better space structure, and by changing the type or position of the substituent group, the space steric hindrance and the power supply capacity are changed, so that the structure and properties of the polymer are regulated, and a polyolefin product with ultrahigh molecular weight, narrow molecular weight distribution, high glass transition temperature, low terminal double bond content and high stereoregularity can be prepared, and has a relatively wide industrial application prospect.

Description

Technical Field

[0001] This invention belongs to the field of polyolefins, specifically relating to a metallocene catalyst containing hydrazide and nitrogen oxides, its preparation method, and its application. Background Technology

[0002] Organic polymer materials have become a pillar of social and scientific development, with polyolefins showing the most rapid growth and widest range of applications. Polyolefin materials are generally produced by the polymerization of α-olefins (ethylene and propylene, or others) under specific conditions. Due to their many excellent properties, they are widely used in various fields such as science and technology, national defense, and the national economy. Therefore, accelerating the development of polyolefin catalysts is of paramount importance to the development of olefin polymerization.

[0003] Patent EP0874005AS first disclosed a type of polyolefin catalyst with Schiff base metal coordination (structural formula shown below). Although there is a new innovation in the catalyst structure, it still has some shortcomings: the copolymerization ability is relatively low, the molecular weight decreases significantly during olefin copolymerization, and the comonomer insertion rate is relatively low, which cannot meet the industrial needs of mass production.

[0004]

[0005] Patent CN1408731A optimizes the above catalyst (the structural formula is shown below), but the catalyst has the disadvantages of low activity, low polymer molecular weight, and wide polymer molecular weight distribution, and it also cannot meet the needs of industrial production.

[0006]

[0007] Meanwhile, Organometallics 2012, 31, 6244 reported a catalyst with an aminoquinoline core and a catalyst metal complex (the structure is shown below). Although this catalyst has a significantly improved insertion rate, its activity is still low and cannot meet the needs of industrial production.

[0008] Summary of the Invention

[0009] To address the aforementioned technical challenges related to catalyst activity, insertion rate, and molecular weight distribution, this invention provides a novel metallocene catalyst for catalyzing olefin polymerization and its preparation method. In the catalyst structure, the nitrogen atoms of the cyclopentadiene and hydrazide are linked by carbon atoms, resulting in a more stable complex structure. Furthermore, the use of nitrogen oxides and metal coordination, compared to traditional phenolic hydroxyl groups, alters the bond length, leading to a better spatial structure. Simultaneously, by changing the type or position of substituents, steric hindrance and electron-donating capacity can be altered, thereby enabling the regulation of polymer structural properties. This allows for the preparation of polyolefin products with ultra-high molecular weight, narrow molecular weight distribution, high glass transition temperature, low terminal double bond content, and high isotacticity, demonstrating broad industrial application prospects.

[0010] Another object of the present invention is to provide the application of the catalyst in the field of olefin polymerization.

[0011] To achieve the above objectives, the present invention adopts the following technical solution:

[0012] This invention provides a metallocene catalyst with the structure shown in formula (1):

[0013]

[0014] In the formula, M is selected from IVB metallic elements, preferably titanium, zirconium, and hafnium;

[0015] R1 is independently selected from hydrogen, C1-C12 alkyl, C3-C12 cycloalkyl, C6-C20 aryl, and C6-C20 alkane-substituted aryl groups, preferably hydrogen, methyl, ethyl, isopropyl, tert-butyl, phenyl, and anthracene.

[0016] R2 is selected from C1 to C12 alkyl groups, preferably methyl, ethyl, propyl, isopropyl, or tert-butyl.

[0017] R3 and R4 are independently selected from hydrogen, halogen, C1-C12 alkyl, C3-C20 cycloalkyl, C6-C20 aryl, C6-C20 alkane-substituted aryl, C6-C20 aryloxy, and C6-C20 aromatic amino, preferably hydrogen, halogen, phenyl, tolyl, dimethylphenyl, tert-butylphenyl, isopropylphenyl, methyl, isobutyl, ethyl, isopropyl, tert-butyl, or hexyl; R3 and R4 may be the same or different, preferably the same;

[0018] X is selected from halogens, C1-C12 alkyl groups, C1-C12 aryl groups, and C1-C12 alkylamino groups; preferably chlorine, methyl, benzyl, or dimethylamino.

[0019] Furthermore, the metallocene catalyst of the present invention preferably has a compound having the structure shown in formulas E1 to E8:

[0020]

[0021] The present invention also provides a method for preparing the above-mentioned metallocene catalyst, comprising the following steps:

[0022] 1) Methyl pyridine-2-carboxylate or its derivatives are mixed with hydrogen peroxide and reacted in acetic acid to prepare pyridine nitride intermediate A;

[0023] 2) Intermediate A and hydrazine hydrate are reacted in an alcohol solvent to prepare intermediate B;

[0024] 3) Intermediate B and alkali metal elements or alkali metal compounds are mixed in organic solvent 1 and pre-reacted at low temperature, and then olefin-rich substances are added to react and obtain intermediate C.

[0025] 4) Intermediate C, alkylating agent, and alkali metal element or alkali metal compound are mixed in organic solvent II and pre-reacted at low temperature, and then ammonium fluoride salt is added to react and obtain intermediate D;

[0026] 5) Intermediate D and dehydrogenating agent are mixed and pre-reacted in organic solvent three, and then the pre-reaction solution is slowly added to organic solvent four containing metal salt to prepare the metallocene catalyst shown in formula (1).

[0027] In step 1) of this invention, the methyl pyridine-2-carboxylate or its derivative has the structure shown in formula (2).

[0028] The definition of R1 is the same as that in equation (1).

[0029] Preferably, it is one or more of the following: methyl pyridine-2-carboxylate, methyl 2-carboxylate-3,5-dimethylpyridine, methyl 2-carboxylate-3,5-diisopropylpyridine, methyl 2-carboxylate-3,5-di-tert-butylpyridine, methyl 2-carboxylate-3,5-diethylpyridine, methyl 2-carboxylate-3,5-dicyclohexylpyridine, and methyl 2-carboxylate-3,5-diphenylpyridine.

[0030] In step 1) of the present invention, the molar ratio of methyl pyridine-2-carboxylate or its derivative to hydrogen peroxide is 1:2 to 10, preferably 1:2 to 3.

[0031] In step 1) of the present invention, the amount of acetic acid used is 0.5 to 10 times the total mass of methyl pyridine-2-carboxylate or its derivatives, preferably 5 to 10 times.

[0032] In step 1) of the present invention, the reaction is carried out at a temperature of 20-118°C, preferably 100-118°C, for a time of 5-16 hours, preferably 5-8 hours.

[0033] In step 1) of this invention, the intermediate A obtained has the structure shown in formula A.

[0034]

[0035] The definition of R1 is the same as that in equation (1);

[0036] Preferably, it is a substituted methyl 2-carboxylate-pyridine nitride, such as methyl 2-carboxylate-3,5-dimethylpyridine nitride, methyl 2-carboxylate-3,5-di-tert-butylpyridine nitride, or methyl 2-carboxylate-3,5-diisopropylpyridine nitride.

[0037] After the reaction described in step 1) of this invention is completed, the process also includes post-processing steps such as separation and purification, which are conventional operations in the field and are not particularly required by this invention.

[0038] In step 2) of this invention, the alcohol solvent is selected from one or more C1-C6 alcohols, preferably one or more methanol and ethanol;

[0039] Preferably, the molar ratio of intermediate A to hydrazine hydrate is 1:2 to 8, more preferably 1:2 to 3;

[0040] The amount of the alcohol solvent used is 0.5 to 10 times the total mass of methyl pyridine-2-carboxylate or its derivatives, preferably 5 to 10 times;

[0041] In step 2), the reaction is carried out at a temperature of 70–90°C, preferably 80–90°C, for a time of 3–16 h, preferably 3–5 h.

[0042] In this invention, the structure of intermediate B is as follows:

[0043] The definition of R1 is the same as that in equation (1);

[0044] In step 2) of this invention, the reaction is carried out in a nitrogen atmosphere; it also includes post-processing procedures such as separation and purification, which are conventional operations in the art and are not particularly required by this invention.

[0045] In step 3) of the present invention, the alkali metal element is selected from one or more of sodium metal, sodium hydride, potassium metal, and sodium hydride, and the alkali metal compound is selected from one or more of C1-C6 alkyl lithium and alkali metal hydrides, preferably one or more of methyl lithium, n-butyl lithium, hexyl lithium, and sodium hydride;

[0046] Preferably, the molar ratio of intermediate B to alkali metal is 1:1 to 5, more preferably 1:1 to 1.4;

[0047] The structural formula of the olefin is shown in Formula 3. The definitions of R3 and R4 are the same as those in equation (1);

[0048] Preferably, it is 6,6-dimethylfulne, 6,6-dicyclohexylfulne, or 6,6-diphenylfulne;

[0049] Preferably, the molar ratio of intermediate B to olefin is 1:1 to 4, more preferably 1:1 to 1.2.

[0050] In step 3) of this invention, the organic solvent is selected from one or more of tetrahydrofuran, diethyl ether, m-xylenebenzene, and methyl tert-butyl ether;

[0051] Preferably, the amount of the organic solvent is 0.5 to 10 times the mass of intermediate B, more preferably 5 to 10 times;

[0052] In step 3) of the present invention, the pre-reaction temperature is -80 to 0°C, preferably -40 to 0°C, and the pre-reaction time is 1 to 5 hours, preferably 1 to 4 hours;

[0053] After adding olefins, the reaction temperature is -80 to 25°C, preferably -40 to 25°C, and the reaction time is 3 to 24 hours, preferably 3 to 6 hours.

[0054] In step 3) of this invention, the reaction is carried out in a nitrogen atmosphere; it also includes post-processing procedures such as separation and purification, which are conventional operations in the art and are not particularly required by this invention.

[0055] In step 4) of the present invention, the alkylating agent has a structure of R2-E, wherein R2 is the same as in Formula 1, and E is a halogen, preferably iodine or bromine;

[0056] Preferably, the alkylating agent is one or more selected from iodomethane, iodoethane, and isopropyl bromide;

[0057] Preferably, the molar ratio of intermediate C to alkylating agent is 1:1 to 4, more preferably 1:1 to 1.3;

[0058] In step 4), the alkali metal element is selected from sodium metal and potassium metal, and the alkali metal compound is selected from one or more of alkali metal hydrides and C1-C6 alkyl lithium, preferably one or more of methyl lithium, n-butyl lithium, hexyl lithium, sodium hydride, and sodium metal.

[0059] Preferably, the molar ratio of intermediate C to alkali metal is 1:0.5 to 5, more preferably 1:0.8 to 1;

[0060] The ammonium fluoride salt is selected from one or more of tetrabutylammonium fluoride, tetrapropylammonium fluoride, and tetratert-butylammonium fluoride;

[0061] Preferably, the molar ratio of intermediate C to ammonium fluoride salt is 1:1 to 4, more preferably 1:1 to 2;

[0062] Preferably, the structure of the intermediate C is as follows: The definitions of R1-R4 are the same as those in equation (1).

[0063] In step 4) of the present invention, the second organic solvent is selected from one or more of tetrahydrofuran, diethyl ether, 1,2-dichloroethane, m-xylenebenzene, n-hexane, and methyl tert-butyl ether; preferably, the amount of the second organic solvent is 0.5 to 10 times the mass of intermediate C, more preferably 5 to 10 times;

[0064] In step 4), the pre-reaction temperature is -80 to 0°C, preferably -40 to 0°C, and the pre-reaction time is 2 to 24 hours, preferably 2 to 5 hours.

[0065] After adding ammonium fluoride, the reaction temperature is -80 to 25°C, preferably 0 to 25°C, and the reaction time is 1 to 16 hours, preferably 1 to 4 hours.

[0066] In step 4) of this invention, the reaction is carried out in a nitrogen atmosphere; it also includes post-processing procedures such as separation and purification, which are conventional operations in the art and are not particularly required by this invention.

[0067] In step 5), the dehydrogenation reagent is selected from alkali metal elements, alkali metal hydrides, C1-C6 alkyl lithium, preferably one or more of sodium metal, sodium hydride, potassium metal, sodium hydride, and C1-C6 alkyl lithium, and more preferably one or more of methyl lithium, n-butyl lithium, hexyl lithium, sodium hydride, and sodium metal.

[0068] Preferably, the molar ratio of intermediate D to the dehydrogenating agent is 1:2 to 12, more preferably 1:4 to 10;

[0069] The metal salt is selected from one or more of IVB metal halides, alkyl compounds, alkylamino compounds, and aryl compounds, preferably one or more of IVB metal halides, alkyl compounds, and aryl compounds; wherein X comes from the metal salt compound.

[0070] Preferably, the molar ratio of intermediate D to metal salt is 1:1 to 2, more preferably 1:1 to 1.2;

[0071] In step 5), organic solvent three and organic solvent four may be the same or different, and organic solvent three and organic solvent four are each independently selected from one or more of tetrahydrofuran, n-hexane, diethyl ether, 1,2-dichloroethane, m-xylenebenzene, cyclohexane, and methyl tert-butyl ether;

[0072] The structure of the intermediate D is as follows: The definitions of R1-R4 are the same as those in equation (1).

[0073] The amount of solvent added can be based on common knowledge in the art. For example, the amount of organic solvent three used is 0.5 to 10 times the mass of intermediate D, preferably 5 to 10 times.

[0074] Preferably, the mass ratio of organic solvent three to organic solvent four is 1:0.8 to 1.1.

[0075] In step 5), the pre-reaction temperature is -80 to 0°C, preferably -40 to 0°C, and the pre-reaction time is 1 to 5 hours, preferably 1 to 2 hours.

[0076] The reaction is carried out at a temperature of -80 to 25°C, preferably -40 to 25°C, and for a time of 2 to 24 hours, preferably 3 to 6 hours.

[0077] In step 5) of this invention, the reaction is carried out in a nitrogen atmosphere; it also includes post-processing procedures such as separation and purification, which are conventional operations in the art and are not particularly required by this invention.

[0078] The present invention also provides the use of the metallocene catalyst for catalyzing olefin solution polymerization;

[0079] Preferably, the olefin is selected from one or more of ethylene, propylene, styrene, 1-butene, 1-hexene, 1-octene, norbornene, and tetracyclododecene;

[0080] More preferably, the metallocene catalyst is particularly suitable for catalyzing the homopolymerization of olefins, such as ethylene and propylene.

[0081] This invention provides a method for carrying out olefin polymerization, comprising the following steps:

[0082] The metallocene catalyst and co-catalyst shown in Formula 1 are dissolved in a solvent, and then an olefin is introduced. The mixture is heated to carry out a polymerization reaction to obtain a polyolefin product.

[0083] The polymerization conditions described in this invention are: polymerization temperature of 0-180℃, polymerization pressure of 1-10 MPa, and the solvent used for polymerization is one or more of toluene, hexane, and heptane.

[0084] The cocatalyst described in this invention is selected from one or more of alkylaluminum and aluminoxanes, with the aluminoxane preferably being one or more of methylaluminoxane, ethylaluminoxane, or isobutylaluminoxane. The alkylaluminum is preferably one or more of trimethylaluminum, triethylaluminum, and tri-n-hexylaluminum.

[0085] The amount of the metallocene catalyst added is 0.1-2 μmol per liter of solvent.

[0086] The molar ratio of aluminum in the co-catalyst to metal M in the main catalyst is 100-1500:1.

[0087] Compared with the prior art, the beneficial effects of the technical solution of the present invention are as follows:

[0088] In the catalyst structure, the nitrogen atoms of cyclopentadiene and hydrazide are linked by carbon atoms, making the complex structure more stable. Furthermore, the use of nitrogen oxides and metal coordination, compared to traditional phenolic hydroxyl groups, results in a better spatial structure due to the change in bond length. At the same time, by changing the type or position of substituents, the steric hindrance and power supply capacity can be altered, thereby enabling the regulation of polymer structural properties. This allows for the preparation of polyolefin products with ultra-high molecular weight, narrow molecular weight distribution, high glass transition temperature, low terminal double bond content, and high isotacticity, which has broad prospects for industrial applications. Detailed Implementation

[0089] The technical solutions of the present invention are further illustrated by the embodiments, but the present invention is not limited thereto. The specific embodiments of the present invention can enable those skilled in the art to have a more comprehensive understanding of the present invention.

[0090] Unless otherwise specified, the experimental methods used in the following embodiments are conventional methods in the art.

[0091] The materials and reagents used in the following examples are all commercially available. The main raw material sources are as follows; unless otherwise specified, other raw materials are common commercially available:

[0092] 2-Methyl 2-carboxylate-3,5-dicyclohexylpyridine, 2-methyl 2-carboxylate-3,5-di-tert-butylpyridine, and 2-methyl 2-carboxylate-3,5-diphenylpyridine were synthesized according to the literature J.Org.Chem.1984,49,1338-1341. The synthesis method is as follows:

[0093] 2-Methyl formate-3,5-di-tert-butylpyridine

[0094]

[0095] Under a nitrogen atmosphere, aluminum tribromide (540 g, 2 mol) was dissolved in 2.5 L of dichloromethane and stirred at -80 °C for 1 h. Then, tert-butylacetylene (328 g, 4 mol) was added and stirred at -80 °C for 1 h. Methyl cyanoformate (250 mL, 2.5 mol) was then added, and the mixture was gradually brought to room temperature. Water and ethyl acetate were added for extraction and separation. Column chromatography (eluent: petroleum ether and ethyl acetate in a volume ratio of 10:1) was performed to give 100 g of methyl 2-formate-3,5-di-tert-butylpyridine, with a yield of 20%.

[0096] 1¹H NMR 1.34 (s, 9H), 1.42 (s, 9H), 4.43 (s, J = 8 Hz, 3H), 7.48 (d, J = 1.5 Hz, 1H), 7.89 (d, J = 1.5 Hz, 1H) 2-Methyl formate-3,5-dicyclohexylpyridine

[0097]

[0098] Under a nitrogen atmosphere, aluminum tribromide (540 g, 2 mol) was dissolved in 2.5 L of dichloromethane and stirred at -80 °C for 1 h. Then, cyclohexylacetylene (432 g, 4 mol) was added and stirred at -80 °C for 1 h. Then, methyl cyanoformate (250 mL, 2.5 mol) was added, and the mixture was gradually brought to room temperature. Water and ethyl acetate were added for extraction and separation. Column chromatography (eluent: petroleum ether and ethyl acetate in a volume ratio of 20:1) was performed to give 140 g of methyl 2-formate-3,5-dicyclohexylpyridine, with a yield of 23%.

[0099] 1 H NMR 1.54(dd,12H),1.61(dd,8H),2.61(s,2H),4.23(s,J=8Hz,3H),7.36(d,J=1.5Hz,1H),7.68(d,J=1.5Hz,1H)

[0100] 2-Methyl formate-3,5-diphenylpyridine

[0101]

[0102] Under a nitrogen atmosphere, aluminum tribromide (540 g, 2 mol) was dissolved in 2.5 L of dichloromethane and stirred at -80 °C for 1 h. Then, phenylacetylene (408 g, 4 mol) was added and stirred at -80 °C for 1 h. Methyl cyanoformate (250 mL, 2.5 mol) was then added, and the mixture was gradually brought to room temperature. Water and ethyl acetate were added for extraction and separation. Column chromatography (eluent: petroleum ether and ethyl acetate in a 5:1 volume ratio) yielded 91 g of methyl 2-formate-3,5-diphenylpyridine, with a yield of 16%.

[0103] 1 H NMR 4.23 (s, J = 8 Hz, 3H), 7.46 (dd, J = 1.5 Hz, 6H) 7.53 (d, J = 1.5 Hz, 4H) 7.66 (d, J = 1.5 Hz, 1H), 7.68 (d, J = 1.5 Hz, 1H).

[0104] 6,6-Dicyclohexylfulene was prepared according to the method described in patent CN114437261A. The specific synthesis method is as follows:

[0105]

[0106] Cyclohexyl ketone (388 g, 2 mol) was dissolved in 2.5 L of tetrahydrofuran under a nitrogen atmosphere and stirred at -10 °C for 1 h. Then, sodium cyclopentadienyl (220 g, 2.5 mol) was added and stirred at -10 °C for 1 h. The mixture was then gradually brought to room temperature, and water and ethyl acetate were added for extraction and separation. Column chromatography (eluent: petroleum ether and ethyl acetate in a volume ratio of 50:1) was performed to give 300 g of 6,6-dicyclohexyl-rich olefin, with a yield of 61%.

[0107] 1 H NMR 1.49(dd,12H),1.78(dd,8H),2.61(s,2H),6.36(d,J=1.5Hz,2H),6.68(d,J=1.5Hz,1H)

[0108] Methyl pyridine-2-carboxylate, methyl 2-carboxylate-3,5-dimethylpyridine, iodomethane, 4-methoxyaniline, ultra-dry dichloromethane, ultra-dry tetrahydrofuran: AR, Innochem;

[0109] Toluene, ultra-dry n-hexane, Isopar E, ethyl acetate, methylaluminoxane, ethylaluminoxane, hafnium tetrachloride, isobutylaluminoxane, trimethylaluminum, triethylaluminum, tri-n-hexylaluminum, titanium tetrachloride, zirconium tetrachloride, tetradimethylamine titanium, tetradimethylamine zirconium, tetrabenzylhafnium: AR, Aladdin;

[0110] n-Butyllithium-hexane solution (1.6M), methyllithium-diethyl ether solution (1.6M), methylmagnesium bromide-toluene (2.2M): AR, Aladdin;

[0111] 80% hydrazine hydrate, acetic acid: AR, Comio;

[0112] Industrial ethanol: 95%, 30% hydrogen peroxide, petroleum ether: 60-90℃, Chinese medicine;

[0113] Deuterated chloroform: AR, Acros;

[0114] Silica gel: AR, 200-300 mesh, Beijing Chemical Reagent Company.

[0115] The main testing methods used to determine the structure in this embodiment of the invention are as follows:

[0116] The intermediate compounds in each step of the following examples were characterized using a nuclear magnetic resonance spectrometer (Brucker ARX-400M).

[0117] The molecular weight distribution of the polymer was obtained by testing with a PL-GPC220 at 150°C using a series of PLgel 10μm MIXED-B separation columns and 1,2,4,-trichlorobenzene as solvent.

[0118] The melting point and glass transition temperature of the polymer were measured using conventional DSC methods. The polymerization activity of the complex was calculated using the following formula: Polymer activity = polymer mass / (metal content of catalyst * polymerization time); the terminal double bonds of the polymer were calculated using iodometric titration.

[0119] high temperature 13 The 1,1,2,2,-tetrachloroethane NMR was obtained using a Brucker DMX at 100 MHz and 120 °C.

[0120] The technical solution of the present invention is described below through specific embodiments.

[0121] Example 1

[0122] Preparation of catalyst E1:

[0123]

[0124] 1) Under a nitrogen atmosphere, methyl 2-carboxylate-3,5-dicyclohexylpyridine (90.3 g, 300 mmol) and 30% hydrogen peroxide (67.8 g, 600 mmol) were mixed in 45 g of acetic acid and reacted at 20 °C for 6 h. The hydrogen peroxide was quenched with sodium thiosulfate, and the mixture was extracted with 100 mL each of water and ethyl acetate. The ethyl acetate was removed under reduced pressure, and the mixture was subjected to column chromatography (eluting agent was petroleum ether and ethyl acetate in a volume ratio of 1:1) to give intermediate A1, 75 g, yield 78%.

[0125] 1 H NMR (400MHz, CDCl3): δ8.48(s,1H),7.30(s,1H),3.81(s,3H),2.72(s,2H),1.85(dd,8H),1.62(dd,8H),1.45(dd,4H).

[0126] 2) Under a nitrogen atmosphere, intermediate A1 (63.4 g, 200 mmol) was dissolved in 32 g of solvent ethanol, and then 80% hydrazine hydrate (16 g, 400 mmol) was added. The mixture was reacted at 70 °C for 3 h, cooled, and filtered to obtain 56 g of intermediate B1, with a yield of 88.1%.

[0127] 1H NMR (400MHz, CDCl3): δ8.48(s,1H),7.30(s,2H),3.81(s,3H),2.72(s,2H),1.85(dd,8H),1.62(dd,8H),1.45(dd,4H).

[0128] 3) Under a nitrogen atmosphere, intermediate B1 (31.7 g, 100 mmol) was dissolved in 16 g of diethyl ether, then n-butyllithium (30.6 g, 100 mmol) was added, and the mixture was reacted at -80 °C for 1 h. Then 6,6-diphenylfulne (23 g, 100 mmol) was added, and the mixture was reacted at -80 °C for 3 h. Water and ethyl acetate were added for extraction and separation, followed by column chromatography (eluting agent was petroleum ether and ethyl acetate in a volume ratio of 1:1) to obtain 45.1 g of intermediate B1, with a yield of 82.2%.

[0129] 1 H NMR (400MHz, CDCl3): δ9.48 (s, 1H), 1 δ8.48(s,1H),4.32(s,2H),6.63(d,2H,J=8.3Hz),6.49(d,2H,J=6.7Hz,Cp),6.42( m,2H,Cp),6.21(s,2H,Cp),2.72(s,2H),1.85(dd,8H),1.62(dd,8H),1.45(dd,4H).

[0130] 4) Under a nitrogen atmosphere, intermediate C1 (27.3 g, 50 mmol) and sodium hydride (0.6 g, 25 mmol) were dissolved in 13.6 g of anhydrous tetrahydrofuran and stirred for 30 min. Then, iodomethane (7.1 g, 50 mmol) was added, and the mixture was reacted at -80 °C for 2 h. Then, tetrabutylammonium fluoride (13 g, 50 mmol) was added, and the mixture was reacted at 0 °C for 1 h. The tetrahydrofuran was removed under reduced pressure, and the mixture was extracted with water and ethyl acetate. The extract was then separated by column chromatography (eluent was petroleum ether and ethyl acetate in a 1:1 volume ratio) to give 24.9 g of intermediate D1, with a yield of 89%.

[0131] 1 H NMR (400MHz, CDCl3): δ9.48 (s, 1H), 1 δ8.48(s,1H),3.81(s,3H),4.32(s,2H),6.63(d,2H,J=8.3Hz),6.49(d,2H,J=6.7Hz,Cp), 6.42(m,2H,Cp),6.21(s,2H,Cp),2.72(s,2H),1.85(dd,8H),1.62(dd,8H),1.45(dd,4H).

[0132] 5) Under a nitrogen atmosphere, intermediate D1 (11.2 g, 20 mmol) was dissolved in 5 g of anhydrous tetrahydrofuran, and methyllithium (8 g, 20 mmol) was added. The reaction was carried out at -80 °C for 1 h. Then the reaction solution was added to a mixed solution of titanium tetrachloride (3.79 g, 20 mmol) and 4 g of anhydrous n-hexane. The reaction was carried out at -80 °C for 2 h. The solvent was removed under reduced pressure, and the solution was extracted with toluene, concentrated and recrystallized to give 6.99 g of catalyst E1, with a yield of 53%.

[0133] 1 H NMR (400MHz, CDCl3): δ9.48 (s, 1H), 1 δ8.48(s,1H),3.81(s,3H),4.32(s,2H),6.83(d,2H,J=8.3Hz),7.49(d,2H,J=6.7Hz,Cp), 6.12(m,2H,Cp),6.91(s,2H,Cp),2.72(s,2H),1.85(dd,8H),1.62(dd,8H),1.45(dd,4H).

[0134] Example 2

[0135] Preparation of catalyst E2:

[0136]

[0137] 1) Under a nitrogen atmosphere, methyl 2-carboxylate-3,5-di-tert-butylpyridine (99.3 g, 400 mmol) and 30% hydrogen peroxide (138.4 g, 1200 mmol) were mixed in 480 g of acetic acid and reacted at 100 °C for 8 h. The hydrogen peroxide was quenched with sodium thiosulfate, and the mixture was extracted with 200 mL each of water and ethyl acetate. The ethyl acetate was removed under reduced pressure, and the mixture was subjected to column chromatography (eluting agent: petroleum ether and ethyl acetate in a volume ratio of 1:1) to give intermediate A2, 90 g, yield 84%.

[0138] 1 H NMR (400MHz, CDCl3): δ8.48(s,1H),7.30(s,1H),3.81(s,3H),1.35(s,9H,tBu),1.32(s,9H,tBu).

[0139] 2) Under a nitrogen atmosphere, intermediate A2 (53 g, 200 mmol) was dissolved in 265 g of solvent ethanol, and then 80% hydrazine hydrate (26 g, 600 mmol) was added. The mixture was reacted at 80 °C for 3 h, cooled, and filtered to obtain 48 g of intermediate B2, with a yield of 88.1%.

[0140] 1H NMR (400MHz, CDCl3): δ8.48(s,1H),7.84(s,2H),3.81(s,3H),1.35(s,9H,tBu),1.32(s,9H,tBu).

[0141] 3) Under a nitrogen atmosphere, intermediate B2 (26.5 g, 100 mmol) was dissolved in 88.5 g of diethyl ether, then n-butyllithium (42.6 g, 140 mmol) was added, and the reaction was carried out at -40 °C for 4 h. Then 6,6-dicyclohexylfulne (29 g, 120 mmol) was added, and the reaction was carried out at -40 °C for 4 h. Water and ethyl acetate were added for extraction and separation, and column chromatography was performed (eluting agent was petroleum ether and ethyl acetate in a volume ratio of 1:1) to give 48.1 g of intermediate C2, with a yield of 94.1%.

[0142] 1 H NMR (400MHz, CDCl3): δ9.48 (s, 1H), 8.48 (s, 1H), 7.32 (s, 1H), 6.63 (d, 1H, J = 8.3Hz), 6.49 (d, 1H, J = 6.7Hz, Cp), 6.42 (m, 2H, Cp ),6.21(s,2H,Cp),4.32(s,2H),2.72(s,2H),1.85(dd,8H),1.62(dd,10H),1.45(dd,4H),1.35(s,9H,tBu),1.32(s,9H,tBu).

[0143] 4) Under a nitrogen atmosphere, intermediate C2 (25 g, 50 mmol) and sodium hydride (0.96 g, 40 mmol) were dissolved in 125 g of anhydrous tetrahydrofuran and stirred for 5 h. Then, iodomethane (9.2 g, 65 mmol) was added and the reaction was carried out at -25 °C for 5 h. Then, tetrabutylammonium fluoride (26 g, 100 mmol) was added and the reaction was carried out at 0 °C for 4 h. Tetrahydrofuran was removed under reduced pressure, and the mixture was extracted with water and ethyl acetate. Column chromatography (eluting agent was petroleum ether and ethyl acetate in a volume ratio of 1:1) was performed to give 24.9 g of intermediate D2, with a yield of 95%.

[0144] 1H NMR (400MHz, CDCl3): δ9.48 (s, 1H), 8.48 (s, 1H), 7.32 (s, 1H), 6.63 (d, 1H, J = 8.3Hz), 6.49 (d, 1H, J = 6.7Hz, Cp), 6.42 (m, 2H, Cp ),6.21(s,2H,Cp),4.32(s,2H),2.62(s,5H),1.85(dd,8H),1.62(dd,10H),1.45(dd,4H),1.35(s,9H,tBu),1.32(s,9H,tBu).

[0145] 5) Under a nitrogen atmosphere, intermediate D2 (10.4 g, 20 mmol) was dissolved in 50 g of anhydrous tetrahydrofuran, and methyllithium (35 g, 80 mmol) was added. The reaction was carried out at -40 °C for 2 h. Then, the reaction solution was added to a mixed solution of zirconium tetrachloride (5.59 g, 24 mmol) and 40 g of anhydrous n-hexane. The reaction was carried out at 0 °C for 4.5 h. The solvent was removed under reduced pressure, and the solution was extracted with toluene, concentrated and recrystallized to give 10.21 g of catalyst E2, with a yield of 78%.

[0146] 1 H NMR (400MHz, CDCl3): δ8.48 (s, 1H), 7.32 (s, 1H), 6.63 (d, 1H, J = 8.3Hz), 6.49 (d, 1H, J = 6.7Hz, Cp), 6.42 (m, 2H, Cp ),6.21(s,2H,Cp),2.62(s,5H),1.85(dd,8H),1.62(dd,10H),1.45(dd,4H),1.35(s,9H,tBu),1.32(s,9H,tBu).

[0147] Example 3

[0148] Preparation of catalyst E3:

[0149]

[0150] 1) Under a nitrogen atmosphere, methyl 2-carboxylate-3,5-di-tert-butylpyridine (99.3 g, 400 mmol) and 30% hydrogen peroxide (138.4 g, 1200 mmol) were mixed in 480 g of acetic acid and reacted at 100 °C for 8 h. The hydrogen peroxide was quenched with sodium thiosulfate, and the mixture was extracted with 200 mL each of water and ethyl acetate. The ethyl acetate was removed under reduced pressure, and the mixture was subjected to column chromatography (eluting agent was petroleum ether and ethyl acetate in a volume ratio of 1:1) to give intermediate A2, 104 g, with a yield of 98%.

[0151] 1H NMR (400MHz, CDCl3): δ8.48(s,1H),7.30(s,1H),3.81(s,3H),1.35(s,9H,tBu),1.32(s,9H,tBu).

[0152] 2) Under a nitrogen atmosphere, intermediate A2 (53 g, 200 mmol) was dissolved in 265 g of solvent ethanol, and then 80% hydrazine hydrate (26 g, 600 mmol) was added. The mixture was reacted at 80 °C for 3 h, cooled, and filtered to obtain 48 g of intermediate B2, with a yield of 88.1%.

[0153] 1 H NMR (400MHz, CDCl3): δ8.48(s,1H),7.84(s,2H),3.81(s,3H),1.35(s,9H,tBu),1.32(s,9H,tBu).

[0154] 3) Under a nitrogen atmosphere, intermediate B2 (26.5 g, 100 mmol) was dissolved in 88.5 g of diethyl ether, then n-butyllithium (153 g, 500 mmol) was added, and the reaction was carried out at 0 °C for 5 h. Then 6,6-diphenylfulne (23 g, 100 mmol) was added, and the reaction was carried out at 25 °C for 6 h. Water and ethyl acetate were added for extraction and separation, and column chromatography was performed (eluent was petroleum ether and ethyl acetate in a volume ratio of 1:1) to give 50 g of intermediate C3, with a yield of 96.1%.

[0155] 1 H NMR (400MHz, CDCl3): δ9.48 (s, 1H), 1 δ8.48(s,1H),4.32(s,2H),6.63(d,2H,J=8.3Hz),6.49(d,2H,J=6.7Hz,C p),6.42(m,2H,Cp),6.21(s,2H,Cp),1.35(s,9H,tBu),1.32(s,9H,tBu).

[0156] 4) Under a nitrogen atmosphere, intermediate C3 (24.8 g, 50 mmol) and sodium hydride (0.96 g, 40 mmol) were dissolved in 45.8 g of anhydrous tetrahydrofuran and stirred for 30 min. Then, iodomethane (7.1 g, 50 mmol) was added, and the mixture was reacted at -40 °C for 5 h. Then, tetrabutylammonium fluoride (13 g, 50 mmol) was added, and the mixture was reacted at 0 °C for 2 h. The tetrahydrofuran was removed under reduced pressure, and the mixture was extracted with water and ethyl acetate. The extract was then separated by column chromatography (eluent was petroleum ether and ethyl acetate in a 1:1 volume ratio) to give 24.9 g of intermediate D1, with a yield of 89%.

[0157] 1H NMR (400MHz, CDCl3): δ9.48 (s, 1H), 1 δ8.48(s,1H),3.81(s,3H),4.32(s,2H),6.63(d,2H,J=8.3Hz),6.49(d,2H,J=6 .7Hz,Cp),6.42(m,2H,Cp),6.21(s,2H,Cp),1.35(s,9H,tBu),1.32(s,9H,tBu).

[0158] 5) Under a nitrogen atmosphere, intermediate D3 (10.19 g, 20 mmol) was dissolved in 533 g of anhydrous tetrahydrofuran, and methyllithium (87.5 g, 200 mmol) was added. The reaction was carried out at 0 °C for 5 h. Then, the reaction solution was added to a mixed solution of hafnium tetrachloride (9.6 g, 30 mmol) and 586.3 g of anhydrous n-hexane, and the reaction was carried out at 25 °C for 6 h. The solvent was removed under reduced pressure, and the solution was extracted with toluene, concentrated, and recrystallized to obtain 10.9 g of catalyst E3, with a yield of 75%.

[0159] 1 H NMR (400MHz, CDCl3): δ9.48 (s, 1H), 1 δ8.48(s,1H),3.81(s,3H),4.32(s,2H),6.83(d,2H,J=8.3Hz),7.49(d,2H,J=6 .7Hz,Cp),6.12(m,2H,Cp),6.91(s,2H,Cp),1.35(s,9H,tBu),1.32(s,9H,tBu).

[0160] Example 4

[0161] Preparation of compound E4

[0162]

[0163] 1) Under a nitrogen atmosphere, methyl 2-carboxylate-3,5-diisopropylpyridine (67.1 g, 300 mmol) and 30% hydrogen peroxide (67.8 g, 600 mmol) were mixed in 126.2 g of acetic acid and reacted at 60 °C for 6 h. The hydrogen peroxide was removed by sodium thiosulfate and then by vacuum extraction. The mixture was extracted with 100 mL each of water and ethyl acetate, and the ethyl acetate was removed by vacuum extraction. The mixture was then subjected to column chromatography (eluting agent: petroleum ether and ethyl acetate in a 1:1 volume ratio) to give intermediate A3, 66 g, with a yield of 93%.

[0164] 1 H NMR (400MHz, CDCl3): δ8.48(s,1H),7.30(s,1H),3.81(s,3H),1.35(s,6H),1.32(s,6H).

[0165] 2) Under a nitrogen atmosphere, intermediate A3 (47.4 g, 200 mmol) was dissolved in 177 g of solvent ethanol, and then 80% hydrazine hydrate (16 g, 400 mmol) was added. The mixture was reacted at 90 °C for 5 h, cooled, and filtered to obtain 40 g of intermediate B3, with a yield of 86.1%.

[0166] 1 H NMR (400MHz, CDCl3): δ8.48(s,1H),7.30(s,2H),3.81(s,3H),1.35(s,6H),1.32(s,6H).

[0167] 3) Under a nitrogen atmosphere, intermediate B3 (23.7 g, 100 mmol) was dissolved in 88.5 g of diethyl ether, then n-butyllithium (30.6 g, 100 mmol) was added, and the reaction was carried out at -40 °C for 6 h. Then 6,6-diphenylfulne (23 g, 100 mmol) was added, and the reaction was carried out at -40 °C for 3 h. Water and ethyl acetate were added for extraction and separation, and column chromatography was performed (eluent was petroleum ether and ethyl acetate in a volume ratio of 1:1) to give 41.1 g of intermediate C4, with a yield of 89.0%.

[0168] 1 H NMR (400MHz, CDCl3): δ9.48 (s, 1H), 1 δ8.48(s,1H),4.32(s,2H),6.63(d,2H,J=8.3Hz),6.49(d,2H,J=6.7Hz,Cp),6.42(m,2H,Cp),6.21(s,2H,Cp),1.35(s,6H),1.32(s,6H).

[0169] 4) Under a nitrogen atmosphere, intermediate C4 (23.3 g, 50 mmol) and sodium hydride (0.96 g, 40 mmol) were dissolved in 45.8 g of anhydrous tetrahydrofuran and stirred for 30 min. Then, iodomethane (7.1 g, 50 mmol) was added, and the mixture was reacted at -40 °C for 5 h. Then, tetrabutylammonium fluoride (13 g, 50 mmol) was added, and the mixture was reacted at 0 °C for 2 h. The tetrahydrofuran was removed under reduced pressure, and the mixture was extracted with water and ethyl acetate. The extract was then separated by column chromatography (eluent was petroleum ether and ethyl acetate in a 1:1 volume ratio) to give 24.9 g of intermediate D4, with a yield of 85%.

[0170] 1 H NMR (400MHz, CDCl3): δ9.48 (s, 1H), 1δ8.48(s,1H),3.81(s,3H),4.32(s,2H),6.63(d,2H,J=8.3Hz),6.49(d,2H ,J=6.7Hz,Cp),6.42(m,2H,Cp),6.21(s,2H,Cp),1.35(s,6H),1.32(s,6H).

[0171] 5) Under a nitrogen atmosphere, intermediate D4 (9.6 g, 20 mmol) was dissolved in 533 g of anhydrous tetrahydrofuran, and methyllithium (87.5 g, 200 mmol) was added. The reaction was carried out at 35 °C for 5 h. Then, the reaction solution was added to a mixed solution of hafnium tetrachloride (9.6 g, 30 mmol) and 586.3 g of anhydrous n-hexane, and the reaction was carried out at 35 °C for 6 h. The solvent was removed under reduced pressure, and the solution was extracted with toluene, concentrated, and recrystallized to obtain 10.9 g of catalyst E4, with a yield of 75%.

[0172] 1 H NMR (400MHz, CDCl3): δ9.48 (s, 1H), 1 δ8.48(s,1H),3.81(s,3H),4.32(s,2H),6.83(d,2H,J=8.3Hz),7.49(d,2H ,J=6.7Hz,Cp),6.12(m,2H,Cp),6.91(s,2H,Cp),1.35(s,6H,),1.32(s,6H)

[0173] Example 5

[0174] Preparation of catalyst E5

[0175]

[0176] The preparation method is the same as in Example 3, except that:

[0177] In step 1), the raw material methyl 2-carboxylate-3,5-di-tert-butylpyridine was replaced with an equimolar amount of methyl 2-carboxylate-3,5-dimethylpyridine (64.7 g, 400 mmol) to obtain 62 g of intermediate A4, with a yield of 84%.

[0178] 1 H NMR (400MHz, CDCl3): δ8.48(s,1H),7.30(s,1H),3.81(s,3H),1.35(s,3H),1.32(s,3H).

[0179] In step 2), raw material A2 was replaced with an equimolar amount of A4 (24.1 g, 200 mmol) to obtain 30.2 g of intermediate B4, with a yield of 83%.

[0180] 1 H NMR (400MHz, CDCl3): δ8.48(s,1H),7.30(s,2H),3.81(s,3H),1.35(s,3H),1.32(s,3H).

[0181] In step 3), the raw material B2 was replaced with an equimolar amount of B4 (18.1 g, 100 mmol) to obtain 36.1 g of intermediate C5, with a yield of 87%.

[0182] 1 H NMR (400MHz, CDCl3): δ9.48 (s, 1H), 1 δ8.48(s,1H),4.32(s,2H),6.63(d,2H,J=8.3Hz),6.49(d,2H,J=6.7Hz,Cp),6.42(m,2H,Cp),6.21(s,2H,Cp),1.35(s,3H),1.32(s,3H).

[0183] In step 4), the starting material C3 was replaced with an equimolar amount of C5 (20.8 g, 50 mmol) to obtain 18.6 g of intermediate D5, with a yield of 88%.

[0184] 1 H NMR (400MHz, CDCl3): δ9.48 (s, 1H), 1 δ8.48(s,1H),3.81(s,3H),4.32(s,2H),6.63(d,2H,J=8.3Hz),6.49(d,2H ,J=6.7Hz,Cp),6.42(m,2H,Cp),6.21(s,2H,Cp),1.35(s,3H),1.32(s,3H).

[0185] In step 5), raw material D3 was replaced with an equimolar amount of D5 (7.91 g, 20 mmol), and hafnium tetrachloride was replaced with an equimolar amount of zirconium tetrachloride (4.66 g, 20 mmol) to prepare catalyst E5, 8.44 g, with a yield of 76%.

[0186] 1 H NMR (400MHz, CDCl3): δ9.48 (s, 1H), 1 δ8.48(s,1H),3.81(s,3H),4.32(s,2H),6.83(d,2H,J=8.3Hz),7.49(d,2H ,J=6.7Hz,Cp),6.12(m,2H,Cp),6.91(s,2H,Cp),1.35(s,3H,),1.32(s,3H)

[0187] Example 6

[0188] Preparation of compound M6

[0189]

[0190] The preparation method is the same as in Example 3, except that:

[0191] In step 1), the starting material methyl 2-carboxylate-3,5-di-tert-butylpyridine was replaced with an equimolar amount of methyl pyridine-2-carboxylate (54.8 g, 400 mmol) to obtain 46 g of intermediate A5, with a yield of 72%.

[0192] 1 H NMR (400MHz, CDCl3): δ8.48(s,1H),7.30(s,3H),3.81(s,3H).

[0193] In step 2), the raw material A2 was replaced with an equimolar amount of A5 (31.8 g, 200 mmol) to obtain 26.2 g of intermediate B5, with a yield of 87%.

[0194] 1 H NMR (400MHz, CDCl3): δ9.21(s,1H),7.30(s,3H),3.81(s,3H).

[0195] In step 3), the raw material B2 was replaced with an equimolar amount of B5 (15.3 g, 100 mmol) to obtain 36.1 g of intermediate C6, with a yield of 94%.

[0196] 1 H NMR (400MHz, CDCl3): δ9.48 (s, 1H), 1 δ9.28(s,1H),4.32(s,2H),6.63(d,2H,J=8.3Hz),6.49(d,2H,J=6.7Hz,Cp),6.42(m,2H,Cp),6.21(s,2H,Cp).

[0197] In step 4), the starting material C3 was replaced with an equimolar amount of C6 (19.1 g, 50 mmol) to obtain 16.6 g of intermediate D6, with a yield of 83%.

[0198] 1 H NMR (400MHz, CDCl3): δ9.48 (s, 1H), 1δ8.48(s,1H),3.81(s,3H),4.32(s,2H),6.63(d,2H,J=8.3Hz),6.49(d,2H,J=6.7Hz,Cp),6.42(m,2H,Cp),6.21(s,2H,Cp).

[0199] In step 5), raw material D3 was replaced with an equimolar amount of D6 (7.81 g, 20 mmol), and titanium tetrachloride was replaced with an equimolar amount of zirconium tetrachloride (4.66 g, 20 mmol) to prepare catalyst E6, 8.44 g, with a yield of 70%.

[0200] 1 H NMR (400MHz, CDCl3): δ9.48 (s, 1H), 1 δ8.48(s,1H),3.81(s,3H),4.32(s,2H),6.83(d,2H,J=8.3Hz),7.49(d,2H,J=6.7Hz,Cp),6.12(m,2H,Cp),6.91(s,2H,Cp).

[0201] Example 7

[0202] Preparation of compound M7

[0203]

[0204] The preparation method in Example 3 was followed, with the only difference being the use of B3 (15.3 g, 100 mmol) from Example 4:

[0205] In step 3), the raw material 6,6-diphenylfulne was replaced with an equimolar amount of 6,6-dimethylfulne (10.6 g, 100 mmol) to obtain 31.1 g of intermediate C7, with a yield of 94%.

[0206] 1 H NMR (400MHz, CDCl3): δ9.48 (s, 1H), 1 δ8.48(s,1H),4.32(s,2H),6.63(d,2H,J=8.3Hz),6.49(d,2H,J=6.7Hz,Cp),6.42(m,2H,Cp),6.21(s,2H,Cp),1.35(s,6H),1.32(s,6H).

[0207] In step 4), the starting material C3 was replaced with an equimolar amount of C7 (19.1 g, 50 mmol) to obtain 16.6 g of intermediate D7, with a yield of 83%.

[0208] 1H NMR (400MHz, CDCl3): δ9.48 (s, 1H), 1 δ8.48(s,1H),3.81(s,3H),4.32(s,2H),6.63(d,2H,J=8.3Hz),6.49(d,2H ,J=6.7Hz,Cp),6.42(m,2H,Cp),6.21(s,2H,Cp),1.35(s,6H),1.32(s,6H).

[0209] In step 5), raw material D3 was replaced with an equimolar amount of D7 (7.81 g, 20 mmol), and titanium tetrachloride was replaced with an equimolar amount of zirconium tetrachloride (4.66 g, 20 mmol) to prepare catalyst E7, 7.44 g, with a yield of 60%.

[0210] 1 H NMR (400MHz, CDCl3): δ9.48 (s, 1H), 1 δ8.48(s,1H),3.81(s,3H),4.32(s,2H),6.83(d,2H,J=8.3Hz),7.49(d,2H ,J=6.7Hz,Cp),6.12(m,2H,Cp),6.91(s,2H,Cp),1.35(s,6H),1.32(s,6H).

[0211] Example 8

[0212] Preparation of compound M8

[0213]

[0214] The preparation method is the same as in Example 3, except that:

[0215] In step 3), the raw material 6,6-diphenylfulne was replaced with an equimolar amount of 6,6-dimethylfulne (10.6 g, 100 mmol) to obtain 22.6 g of intermediate C8.

[0216] 1 H NMR (400MHz, CDCl3): δ6.98 (d, 1H, J = 6.3Hz), 6.65 (d, 1H, J = 8.3Hz), 6.49 (d, 1H, J = 6.7Hz, Cp ),6.42(m,2H,Cp),3.73(s,2H,CH2),2.89(d,2H,J=8.7Hz,Cp),2.29(s,3H,Me),1.35(s,9H, t Bu), 1.32(s, 9H, t Bu).

[0217] In step 4), the raw material C3 was replaced with an equimolar amount of C8 (18.8 g, 50 mmol) to obtain 16.9 g of intermediate D8.

[0218] 1 H NMR (400MHz, CDCl3): δ9.65 (s, 1H, OH), 6.98 (d, 1H, J = 6.3Hz), 6.65 (d, 1H, J =

[0219] 8.3Hz),6.49(d,1H,J=6.7Hz,Cp),6.42(m,2H,Cp),3.63(s,2H,CH2),2.89(d,2H,J=8.7Hz,Cp),2.29(s,3H,Me),1.35(s,9H, t Bu), 1.32(s, 9H, t Bu), 1.28(s, 6H, Me).

[0220] In step 5), raw material D3 was replaced with an equimolar amount of D8 (7.63 g, 20 mmol), and titanium tetrachloride was replaced with an equimolar amount of zirconium tetrachloride (4.66 g, 20 mmol) to prepare catalyst E8, 8.04 g.

[0221] 1 H NMR (400MHz, CDCl3): δ6.98 (d, 1H, J = 6.3Hz), 6.65 (d, 1H, J = 8.3Hz), 6.49 (d, 2H ,J=6.7Hz,Cp),6.42(m,2H,Cp),3.63(s,2H,CH2),2.29(s,3H,Me),1.35(s,9H, t Bu), 1.32(s, 9H, t Bu), 1.28(s,6H,Me), 0.88(s,6H).

[0222] Example 9

[0223] Propylene homopolymerization was catalyzed by catalyst E1:

[0224] In a 1L dry polymerization reactor, 500mL of toluene and 0.60mg (1μmol) of catalyst E1 were added, along with trimethylaluminum at a molar ratio of Al:Ti = 1000:1. Propylene was introduced at 50°C at a flow rate of 1000g / min, and the gauge pressure was adjusted to 4MPa and kept constant. After stirring vigorously for 1 hour, the mixture was cooled to room temperature and the pressure was released.

[0225] The reaction solution was neutralized with an ethanol solution acidified with 5% hydrochloric acid to obtain a polymer precipitate. The precipitate was washed several times with ethanol and water and dried under vacuum to constant weight to obtain 52.4 g of polypropylene. The catalyst and polymer properties were tested, and the results are shown in Table 1.

[0226] Example 10

[0227] Propylene homopolymerization was catalyzed by catalyst E2:

[0228] The preparation method is the same as in Example 9, except that:

[0229] When catalyst E1 was replaced with an equimolar amount of catalyst E2 (0.64 mg, 1 μmol), 130.3 g of polypropylene was obtained. The catalyst and polymer properties were tested, and the results are shown in Table 1.

[0230] Example 11

[0231] Propylene homopolymerization was catalyzed by catalyst E3:

[0232] The preparation method is the same as in Example 9, except that:

[0233] When catalyst E1 was replaced with an equimolar amount of catalyst E3 (0.73 mg, 1 μmol), 60.4 g of polypropylene was obtained. The catalyst and polymer properties were tested, and the results are shown in Table 1.

[0234] Example 12

[0235] Propylene homopolymerization was catalyzed by catalyst E4.

[0236] The preparation method is the same as in Example 9, except that:

[0237] When catalyst E1 was replaced with an equimolar amount of catalyst E4 (0.61 mg, 1 μmol), 90.1 g of polypropylene was obtained. The catalyst and polymer properties were tested, and the results are shown in Table 1.

[0238] Example 13

[0239] Propylene homopolymerization was catalyzed by catalyst E5:

[0240] The preparation method is the same as in Example 9, except that:

[0241] When catalyst E1 was replaced with an equimolar amount of catalyst E5 (0.56 mg, 1 μmol), 101.1 g of polypropylene was obtained. The catalyst and polymer properties were tested, and the results are shown in Table 1.

[0242] Example 14

[0243] Propylene homopolymerization was catalyzed by catalyst E6:

[0244] The preparation method is the same as in Example 9, except that:

[0245] When catalyst E1 was replaced with an equimolar amount of catalyst E6 (0.53 mg, 1 μmol), 46.1 g of polypropylene was obtained. The catalyst and polymer properties were tested, and the results are shown in Table 1.

[0246] Example 15

[0247] Propylene homopolymerization was catalyzed by catalyst E7.

[0248] The preparation method is the same as in Example 9, except that:

[0249] When catalyst E1 was replaced with an equimolar amount of catalyst E7 (0.60 mg, 1 μmol), 65.3 g of polypropylene was obtained. The catalyst and polymer properties were tested, and the results are shown in Table 1.

[0250] Example 16

[0251] Propylene homopolymerization was catalyzed by catalyst E8:

[0252] The preparation method is the same as in Example 9, except that:

[0253] Catalyst E1 was replaced with an equimolar amount of catalyst E8 (0.049 mg, 0.1 μmol), yielding 2.54 g of polypropylene. The catalyst and polymer properties were tested, and the results are shown in Table 1. Comparative Example 1

[0254] Catalyst M9 was prepared as shown below using the method described in Example 2 of patent CN102464751A.

[0255]

[0256] The preparation method is the same as in Example 9, except that:

[0257] The catalyst E1 was replaced with an equimolar amount of catalyst M9 (0.64 mg, 1 μmol) to obtain 2.2 g of polypropylene. The catalyst and polymer properties were tested, and the results are shown in Table 1.

[0258] Comparative Example 2

[0259] Catalyst M10 was prepared as shown below using the method of Example 1 of patent CN1408731A.

[0260]

[0261] The preparation method is the same as in Example 9, except that:

[0262] The catalyst E1 was replaced with an equimolar amount of catalyst M10 (2.4 mg, 5 μmol) to obtain 0.4 g of polypropylene. The catalyst and polymer properties were tested, and the results are shown in Table 1.

[0263] Comparative Example 3

[0264] Catalyst M11, as shown below, was prepared using the method described in Example 2 of patent CN102464751A.

[0265]

[0266] The preparation method is the same as in Example 9, except that:

[0267] The catalyst E1 was replaced with an equimolar amount of catalyst M10 (0.64 mg, 1 μmol) to obtain 2.4 g of polypropylene. The catalyst and polymer properties were tested, and the results are shown in Table 1.

[0268] Table 1. Performance test results of catalysts and polymers in the examples and comparative examples.

[0269]

[0270]

[0271] In Table 1, polymerization conditions are as follows: a: measured by GPC; b: measured by DSC; c: [mmmm] represents the isomorphism of the polymer, determined by high temperature. 13 d: Measured by C NMR; d: Measured by iodometric titration.

[0272] The embodiments of the present invention have been described in detail above, but the present invention is not limited to the above embodiments. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A metallocene catalyst, characterized in that, Its structure is shown in equation (1): （1） In the formula, M is selected from IVB metallic elements. R1 is independently selected from hydrogen, C1-C12 alkyl, and C3-C12 cycloalkyl; R2 is selected from C1 to C12 alkyl, R3 and R4 are independently selected from C3 to C20 cycloalkyl, C6 to C20 aryl, and C6 to C20 alkane-substituted aryl, respectively. R3 and R4 may be the same or different, and X is selected from C1 to C12 alkyl.

2. The metallocene catalyst according to claim 1, characterized in that, M is selected from titanium, zirconium, and hafnium; R1 is hydrogen, methyl, ethyl, isopropyl, or tert-butyl. R2 is methyl, ethyl, propyl, isopropyl, or tert-butyl; R3 and R4 are independently selected from phenyl, tolyl, dimethylphenyl, tert-butylphenyl, and isopropylphenyl, respectively; R3 and R4 are the same; X is selected from methyl.

3. The metallocene catalyst according to claim 1 or 2, characterized in that, The metallocene catalyst described herein has the structure shown in formulas E1 to E8 as follows: 。 4. A method for preparing a metallocene catalyst according to any one of claims 1-3, characterized in that, Includes the following steps: 1) Methyl pyridine-2-carboxylate or its derivatives are mixed with hydrogen peroxide and reacted in acetic acid to prepare pyridine nitride intermediate A; 2) Intermediate A and hydrazine hydrate are reacted in an alcohol solvent to prepare intermediate B; 3) Intermediate B and alkali metal elements or alkali metal compounds are mixed in organic solvent 1 and pre-reacted at low temperature, and then olefin-rich substances are added to react and obtain intermediate C. 4) Intermediate C, alkylating agent, and alkali metal element or alkali metal compound are mixed in organic solvent II and pre-reacted at low temperature, and then ammonium fluoride salt is added to react and obtain intermediate D. 5) Intermediate D and dehydrogenating agent are mixed and pre-reacted in organic solvent three, and then the pre-reaction solution is slowly added to organic solvent four containing metal salt to prepare the metallocene catalyst shown in formula (1).

5. The preparation method according to claim 4, characterized in that, In step 1), the methyl pyridine-2-carboxylate or its derivative has the structure shown in formula (2). (2), where the definition of R1 is the same as that in equation (1).

6. The preparation method according to claim 5, characterized in that, The methyl pyridine-2-carboxylate or its derivatives are one or more selected from methyl pyridine-2-carboxylate, methyl 2-carboxylate-3,5-dimethylpyridine, methyl 2-carboxylate-3,5-diisopropylpyridine, methyl 2-carboxylate-3,5-di-tert-butylpyridine, methyl 2-carboxylate-3,5-diethylpyridine, methyl 2-carboxylate-3,5-dicyclohexylpyridine, and methyl 2-carboxylate-3,5-diphenylpyridine.

7. The preparation method according to claim 4, characterized in that, In step 1), the molar ratio of methyl pyridine-2-carboxylate or its derivative to hydrogen peroxide is 1:2 to 10.

8. The preparation method according to claim 7, characterized in that, In step 1), the molar ratio of methyl pyridine-2-carboxylate or its derivative to hydrogen peroxide is 1:2 to 3.

9. The preparation method according to claim 4, characterized in that, In step 1), the amount of acetic acid used is 0.5 to 10 times the total mass of methyl pyridine-2-carboxylate or its derivatives.

10. The preparation method according to claim 9, characterized in that, In step 1), the amount of acetic acid used is 5 to 10 times the total mass of methyl pyridine-2-carboxylate or its derivatives.

11. The preparation method according to claim 9, characterized in that, In step 1), the reaction temperature is 20–118°C and the time is 5–16 h.

12. The preparation method according to claim 11, characterized in that, In step 1), the reaction temperature is 100–118°C, and the reaction time is 5–8 h.

13. The preparation method according to claim 4, characterized in that, In step 1), the intermediate A obtained has the structure shown in formula A. （A）， The definition of R1 is the same as that in equation (1).

14. The preparation method according to claim 13, characterized in that, The intermediate A is methyl 2-carboxylate-3,5-dimethylpyridine oxynitride, methyl 2-carboxylate-3,5-di-tert-butylpyridine oxynitride, or methyl 2-carboxylate-3,5-diisopropylpyridine oxynitride.

15. The preparation method according to claim 4, characterized in that, In step 2), the alcohol solvent is selected from one or more C1-C6 alcohols.

16. The preparation method according to claim 15, characterized in that, In step 2), the alcohol solvent is one or more of methanol and ethanol.

17. The preparation method according to claim 4, characterized in that, The molar ratio of intermediate A to hydrazine hydrate is 1:2 to 8.

18. The preparation method according to claim 17, characterized in that, The molar ratio of intermediate A to hydrazine hydrate is 1:2 to 3.

19. The preparation method according to claim 4, characterized in that, The amount of the alcohol solvent used is 0.5 to 10 times the total mass of methyl pyridine-2-carboxylate or its derivatives.

20. The preparation method according to claim 19, characterized in that, The amount of the alcohol solvent used is 5 to 10 times the total mass of methyl pyridine-2-carboxylate or its derivatives.

21. The preparation method according to claim 4, characterized in that, In step 2), the reaction temperature is 70–90°C and the time is 3–16 h.

22. The preparation method according to claim 21, characterized in that, In step 2), the reaction is carried out at a temperature of 80–90°C for 3–5 hours.

23. The preparation method according to claim 4, characterized in that, The structure of intermediate B is as follows: (B), where the definition of R1 is the same as that in equation (1).

24. The preparation method according to claim 4, characterized in that, In step 3), the alkali metal element is selected from one or more of sodium metal, sodium hydride, potassium metal, and sodium hydride, and the alkali metal compound is selected from one or more of C1-C6 alkyllithium and alkali metal hydrides.

25. The preparation method according to claim 24, characterized in that, The alkali metal element or alkali metal compound is one or more of methyllithium, n-butyllithium, hexyllithium, and sodium hydride.

26. The preparation method according to claim 4, characterized in that, The molar ratio of intermediate B to alkali metal is 1:1 to 5.

27. The preparation method according to claim 26, characterized in that, The molar ratio of intermediate B to alkali metal is 1:1 to 1.

4.

28. The preparation method according to claim 4, characterized in that, The structural formula of the olefin is shown in Formula 3. (3), where the definitions of R3 and R4 are the same as those in equation (1).

29. The preparation method according to claim 28, characterized in that, The enriched ene is 6,6-dimethyl-rich ene, 6,6-dicyclohexyl-rich ene, or 6,6-diphenyl-rich ene.

30. The preparation method according to claim 4, characterized in that, The molar ratio of intermediate B to olefin is 1:1 to 4.

31. The preparation method according to claim 30, characterized in that, The molar ratio of intermediate B to olefin is 1:1 to 1.

2.

32. The preparation method according to claim 4, characterized in that, In step 3), the organic solvent is selected from one or more of tetrahydrofuran, diethyl ether, m-xylene, benzene, and methyl tert-butyl ether.

33. The preparation method according to claim 4, characterized in that, The amount of the organic solvent is 0.5 to 10 times the mass of intermediate B.

34. The preparation method according to claim 33, characterized in that, The amount of the organic solvent is 5 to 10 times the mass of intermediate B.

35. The preparation method according to claim 4, characterized in that, In step 3), the pre-reaction temperature is -80 to 0℃ and the pre-reaction time is 1 to 5 hours.

36. The preparation method according to claim 35, characterized in that, In step 3), the pre-reaction temperature is -40 to 0℃ and the pre-reaction time is 1 to 4 hours.

37. The preparation method according to claim 4, characterized in that, After adding olefins, the reaction temperature is -80 to 25°C, and the reaction time is 3 to 24 hours.

38. The preparation method according to claim 37, characterized in that, After adding olefins, the reaction temperature is -40 to 25°C, and the reaction time is 3 to 6 hours.

39. The preparation method according to claim 4, characterized in that, In step 4), the alkylating agent has the structure R2-E, where R2 is the same as in Formula 1 and E is a halogen.

40. The preparation method according to claim 39, characterized in that, The alkylating agent is one or more of iodomethane, iodoethane, and isopropyl bromide.

41. The preparation method according to claim 39, characterized in that, The molar ratio of intermediate C to alkylating agent is 1:1 to 4.

42. The preparation method according to claim 40, characterized in that, The molar ratio of intermediate C to alkylating agent is 1:1 to 1.

3.

43. The preparation method according to claim 4, characterized in that, In step 4), the alkali metal element is selected from sodium metal and potassium metal, and the alkali metal compound is selected from one or more of alkali metal hydrides and C1-C6 alkyl lithium.

44. The preparation method according to claim 43, characterized in that, In step 4), the alkali metal element or alkali metal compound is one or more of methyl lithium, n-butyl lithium, hexyl lithium, sodium hydride, and metallic sodium.

45. The preparation method according to claim 4, characterized in that, The molar ratio of intermediate C to alkali metal is 1:0.5 to 5.

46. ​​The preparation method according to claim 45, characterized in that, The molar ratio of intermediate C to alkali metal is 1:0.8 to 1.

47. The preparation method according to claim 4, characterized in that, The ammonium fluoride salt is selected from one or more of tetrabutylammonium fluoride, tetrapropylammonium fluoride, and tetratert-butylammonium fluoride.

48. The preparation method according to claim 4, characterized in that, The molar ratio of intermediate C to ammonium fluoride salt is 1:1 to 4.

49. The preparation method according to claim 48, characterized in that, The molar ratio of intermediate C to ammonium fluoride salt is 1:1 to 2.

50. The preparation method according to claim 4, characterized in that, The structure of intermediate C is as follows: (C), where the definitions of R1-R4 are the same as in equation (1).

51. The preparation method according to claim 4, characterized in that, In step 4), the organic solvent 2 is selected from one or more of tetrahydrofuran, diethyl ether, 1,2-dichloroethane, m-xylenebenzene, n-hexane, and methyl tert-butyl ether.

52. The preparation method according to claim 4, characterized in that, The amount of organic solvent II used is 0.5 to 10 times the mass of intermediate C.

53. The preparation method according to claim 52, characterized in that, The amount of organic solvent II used is 5 to 10 times the mass of intermediate C.

54. The preparation method according to claim 4, characterized in that, In step 4), the pre-reaction temperature is -80 to 0℃, and the pre-reaction time is 2 to 24 hours.

55. The preparation method according to claim 54, characterized in that, In step 4), the pre-reaction temperature is -40 to 0℃ and the pre-reaction time is 2 to 5 hours.

56. The preparation method according to claim 4, characterized in that, After adding ammonium fluoride, the reaction temperature is -80 to 25°C and the reaction time is 1 to 16 hours.

57. The preparation method according to claim 56, characterized in that, After adding ammonium fluoride, the reaction temperature is 0–25℃ and the reaction time is 1–4 h.

58. The preparation method according to claim 4, characterized in that, In step 5), the dehydrogenation reagent is selected from alkali metal elements, alkali metal hydrides, and C1-C6 alkyl lithium.

59. The preparation method according to claim 58, characterized in that, In step 5), the dehydrogenation reagent is selected from one or more of sodium metal, sodium hydride, potassium metal, sodium hydride, and C1-C6 alkyllithium.

60. The preparation method according to claim 4, characterized in that, In step 5), the molar ratio of intermediate D to dehydrogenating reagent is 1:2 to 12.

61. The preparation method according to claim 60, characterized in that, In step 5), the molar ratio of intermediate D to dehydrogenating reagent is 1:4 to 10.

62. The preparation method according to claim 4, characterized in that, The metal salt is selected from one or more of the following: metal halides, alkyl compounds, alkylamino compounds, and aryl compounds, wherein X comes from the metal salt compound.

63. The preparation method according to claim 4, characterized in that, The molar ratio of intermediate D to metal salt is 1:1 to 2.

64. The preparation method according to claim 63, characterized in that, The molar ratio of intermediate D to metal salt is 1:1 to 1.

2.

65. The preparation method according to claim 4, characterized in that, In step 5), organic solvent three and organic solvent four may be the same or different, and organic solvent three and organic solvent four are each independently selected from one or more of tetrahydrofuran, n-hexane, diethyl ether, 1,2-dichloroethane, m-xylenebenzene, cyclohexane, and methyl tert-butyl ether.

66. The preparation method according to claim 4, characterized in that, The structure of the intermediate D is as follows: (D), where the definitions of R1-R4 are the same as in equation (1).

67. The preparation method according to claim 4, characterized in that, The mass ratio of organic solvent three to organic solvent four is 1:0.8 to 1.

1.

68. The preparation method according to claim 4, characterized in that, In step 5), the pre-reaction temperature is -80 to 0°C and the pre-reaction time is 1 to 5 hours.

69. The preparation method according to claim 4, characterized in that, In step (5), the reaction temperature is -80 to 25°C and the reaction time is 2 to 24 hours.

70. Use of a metallocene catalyst according to any one of claims 1-3 or a metallocene catalyst prepared by any one of claims 4-69 for catalyzing olefin solution polymerization.

71. The use according to claim 70, wherein, The olefin is selected from one or more of ethylene, propylene, styrene, 1-butene, 1-hexene, 1-octene, norbornene, and tetracyclododecene.

72. The use according to claim 70, wherein the olefin solution polymerization is a homopolymer.

73. A method for olefin polymerization, comprising the following steps: The metallocene catalyst according to any one of claims 1-3 or the metallocene catalyst and co-catalyst prepared by the preparation method according to any one of claims 4-69 are dissolved in a solvent, and then olefins are introduced and heated to carry out a polymerization reaction to obtain a polyolefin product.

74. The method according to claim 73, wherein the polymerization conditions are: polymerization temperature of 0-180℃, polymerization pressure of 1-10 MPa, and the solvent used for polymerization is one or more of toluene, hexane, and heptane.

75. The method according to claim 73, wherein the co-catalyst is selected from one or more of alkylaluminum and aluminoxane.

76. The method according to claim 73, wherein the amount of metallocene catalyst added is 0.1-2 μmol per liter of solvent.

77. The method according to claim 73, wherein the molar ratio of aluminum in the co-catalyst to metal element M in the main catalyst is 100-1500:1.

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