Metallocene compound, preparation method, metallocene catalyst and application of metallocene catalyst

Abstract

The invention relates to the technical field of chemical engineering, and discloses a metallocene compound, a preparation method, a metallocene catalyst and an application of the metallocene catalyst. The chemical structure of the metallocene compound provided by the invention comprises a fluorenyl ligand, a metallocene ligand, a bridging structure and a metal part, and an adsorption group with a micropore effect is introduced into the fluorenyl ligand, so that when the metallocene compound provided by the invention interacts with cocatalysts such as organic boron, organic aluminum and the like, the metallocene compound has the advantages that the adsorption efficiency is improved; compared with the prior art, the catalyst provided by the invention has the advantages of high saturated adsorption capacity, increase of the concentration of the cocatalyst around the metal center, and substantial enhancement of the activity and thermal stability of the catalyst, so high-activity catalysis of alpha-olefin polymerization can be realized, the usage amount of the cocatalyst is reduced, and the production cost of polyolefin is reduced.

Description

Technical Field

[0001] The present application relates to the field of chemical technology, and in particular to a metallocene compound, a preparation method and a metallocene catalyst and applications thereof. Background Art

[0002] Polyolefins are a class of polymer materials formed by the polymerization of olefin monomers, and are widely used in various fields of industrial production and daily life. The iterative upgrade of polyolefin technology is inseparable from the development of polyolefin catalysts. Currently, the industrialized olefin polymerization catalysts mainly include Ziegler-Natta catalysts and metallocene catalysts. Among them, metallocene catalysts refer to a catalytic system composed of a complex of a Group IVB transition metal element (such as Ti, Zr, Hf) as the main catalyst, an alkylaluminoxane (such as methylaluminoxane, abbreviated as MAO) or an organic boron compound (such as B(C6F5)3) as a co-catalyst, and the ligand of the transition metal element contains at least one metallocene (Cp - ) or its derivatives.

[0003] Metallocene catalysts have shown outstanding advantages in the development of new polyolefin materials due to their high polymerization activity, excellent copolymerization performance, and the ability to precisely control polymer structure, molecular weight, and distribution. However, metallocene catalysts require a large amount of modified methylaluminoxane (MMAO for short) as a scavenger and co-catalyst for the reaction system in the production of high-end polyolefins. This is not only costly, but also severely insufficient in global MMAO production capacity, which limits the supply of high-end polyolefin products. Increasing the activity of the main catalyst can reduce the amount of MMAO used. Therefore, it is urgent to develop a new type of metallocene catalyst with high catalytic activity to reduce the cost of polyolefin production. Summary of the invention

[0004] The present application provides a metallocene compound and a preparation method thereof, aiming to improve the catalytic activity of the metallocene catalyst to a certain extent and reduce the production cost of polyolefins.

[0005] In the first aspect, the present application provides a metallocene compound, the chemical structure of which includes a fluorenyl ligand, a locene ligand, a bridging structure and a metal part; the metallocene compound has a structure shown in formula (I):

[0006]

[0007] wherein A1, A2, A3, and A4 are each independently selected from H or an adsorption group, and at least one of A1-A4 is selected from an adsorption group, and the adsorption group is a bulky group that can adsorb organic boron or organic aluminum;

[0008] R1, R2, R3, R4, R5, and R6 are each independently selected from H, halogen, and a substituted or unsubstituted G group, wherein the G group includes C1-C40 Alkyl, C3-C 40 Cycloalkyl, C2-C 40 Heterocycloalkyl, C6-C 60 Aryl, C4-C 60 Heteroaryl, C7-C 60 Aralkyl, C6-C 60 Any one of the heteroarylalkyl groups;

[0009] L is selected from C, Si, Ge or Sn;

[0010] M is selected from Ti, Zr or Hf;

[0011] X is selected from halogen, substituted or unsubstituted Y group, the Y group includes C1-C 30 Alkyl, C3-C 30 Cycloalkyl, C2-C 30 Heterocycloalkyl, C2-C 20 Unsaturated hydrocarbon groups, C6-C 30 Aryl, C4-C 30 Heteroaryl, C5-C 30 Aralkyl, C5-C 30 Any one of the heteroarylalkyl groups;

[0012] The halogen is at least one of F, Cl, Br and I.

[0013] The metallocene compound provided in the present application introduces an adsorption group with a microporous effect into the fluorene-based ligand, so that the metallocene compound of the present application can exhibit a strong saturated adsorption capacity when interacting with co-catalysts such as organic boron and organic aluminum, which can increase the concentration of the co-catalyst around the metal center and significantly enhance the activity and thermal stability of the catalyst, thereby catalyzing the polymerization of α-olefins with high activity, while also reducing the amount of co-catalyst used and reducing the production cost of polyolefins.

[0014] In an optional embodiment, the adsorption group is selected from adamantyl or a derivative of adamantyl, wherein the derivative of adamantyl includes a Q group and at least one adamantyl group, wherein the Q group shares a carbon atom with the adamantyl group or the Q group is connected to the adamantyl group via a covalent bond; wherein the Q group is selected from a heteroatom, a T group, a halogen-substituted T group or a T group containing a heteroatom, wherein the T group includes C1-C 20 Alkyl, C2-C 20 Cycloalkyl, C4-C 30 Aryl, C5-C 30At least one of the arylalkyl groups, the heteroatom is selected from at least one of O, N, P, S, Si, and Ge. In some embodiments, the derivative of the adamantyl group is connected to the fluorenyl group through the adamantyl group or the Q group, and the derivative of the adamantyl group is selected from any one of the adamantyl group substituted with a C1-C5 alkyl group, the adamantyl group substituted with a C2-C5 heterocycloalkyl group, the spirocyclic group formed by the C2-C5 heterocycloalkyl group and the adamantyl group, the adamantyl-substituted amine group, the adamantyl-substituted alkyl group, and the adamantyl-substituted phosphine group. It should be noted that the molecular structure of adamantane has a high degree of spatial symmetry and structural rigidity. The introduction of adamantyl groups or their derivatives into metallocene compounds can increase the structural rigidity and specific surface area of ​​metallocene compounds, which is conducive to the formation of a stable void structure, thereby producing a micropore effect.

[0015] The present application has found that the adamantane group or its derivatives have good adaptability in the skeleton of the metallocene compound. On the one hand, the adamantane group or its derivatives are a large-volume group that can limit the three-dimensional geometric structure of the metallocene compound. Introducing the adamantane group or its derivatives into the fluorenyl ligand of the metallocene compound can better regulate the steric effect of the metal active center, so that the metallocene catalyst obtains a higher catalytic activity. On the other hand, the adamantane group or its derivatives have a microporous effect, so that organic boron and / or organic aluminum can diffuse into the microporous inner surface of the metallocene compound to achieve adsorption equilibrium. Therefore, the metallocene compound can show a strong saturated adsorption capacity for organic boron and / or organic aluminum, thereby increasing the concentration of the co-catalyst around the metal center, enhancing the thermal stability of the catalyst, and then catalyzing the polymerization of α-olefins with high activity, while also reducing the amount of the co-catalyst and reducing the production cost of polyolefins.

[0016] In an optional embodiment, the G group includes C1-C 10 Alkyl, C3-C 10 Cycloalkyl, C2-C6 heterocycloalkyl, C6-C 15 Aryl, C4-C 15 Heteroaryl, C7-C 15 Aralkyl, C6-C 15 Any one of the heteroarylalkyl groups.

[0017] In an optional embodiment, the substituent in the substituted G group is selected from any one of halogen, C1-C5 alkyl, C1-C5 alkoxy, and C1-C5 haloalkyl.

[0018] In some embodiments, the substituted or unsubstituted G group includes any one of methyl, ethyl, propyl, tert-butyl, cyclohexyl, phenyl, methylphenyl, methoxyphenyl, fluorophenyl, trifluoromethylphenyl, tert-butylphenyl, and biphenyl.

[0019] In an optional embodiment, the Y group includes a C1-C5 alkyl group, a C3-C 10 Cycloalkyl, C2-C6 heterocycloalkyl, C2-C 10 Unsaturated hydrocarbon groups, C6-C 15 Aryl, C4-C 15 Heteroaryl, C7-C 15 Aralkyl, C6-C 15 Any one of the heteroarylalkyl groups.

[0020] In an optional embodiment, the substituent in the substituted Y group is selected from any one of halogen, C1-C5 alkyl, C1-C5 alkoxy, and C1-C5 haloalkyl.

[0021] In an optional embodiment, the substituted or unsubstituted Y group includes any one of a methyl group and a benzyl group.

[0022] In an optional embodiment, the fluorenyl ligand is selected from any one of the following structures:

[0023]

[0024]

[0025] In an optional embodiment, the carbonyl ligand is selected from any one of the following structures:

[0026]

[0027] In an optional embodiment, the bridging structure is selected from any one of the following structures:

[0028]

[0029]

[0030] In an optional embodiment, the metallocene compound is selected from any one of the following structures:

[0031]

[0032]

[0033]

[0035] In a second aspect, the present application provides a method for preparing the metallocene compound described in the first aspect, comprising the following steps:

[0036]

[0037] 1) In a first organic solvent, compound i is reacted with a first hydrogen extraction agent at a reaction temperature of T1 and a reaction time of t1; then compound ii is added to continue the reaction at a reaction temperature of T2 and a reaction time of t2 to obtain compound iii;

[0038] 2) In a second organic solvent, compound iii is reacted with a second hydrogen extraction agent at a reaction temperature of T3 and a reaction time of t3; then a metal M salt or a metal M organic compound is added to continue the reaction at a reaction temperature of T4 and a reaction time of t4 to obtain a metallocene compound represented by formula I.

[0039] The preparation method of the present application has a short synthesis route and is easy to operate, and only requires two steps of reaction to obtain the target compound, thus meeting the needs of large-scale production.

[0040] In an optional embodiment, the first organic solvent and the second organic solvent are each independently selected from at least one of toluene, xylene, pentane, cyclopentane, n-hexane, cyclohexane, n-heptane, methylcyclohexane, octane, isooctane, and tetrahydrofuran.

[0041] In an optional embodiment, the first hydrogen withdrawal agent and the second hydrogen withdrawal agent are each independently selected from at least one of alkyl lithium, phenyl lithium, sodium hydride, potassium hydride, lithium hydride, tetramethylethylenediamine, lithium bistrimethylsilylamide, sodium bistrimethylsilylamide, lithium diisopropylamide, and potassium carbonate.

[0042] In an optional embodiment, the molar ratio of the compound i to the first hydrogen removal agent is 1:1.0-1.5.

[0043] In an optional embodiment, the molar ratio of the compound i to the compound ii is 1:1.0-1.5.

[0044] In an optional embodiment, the T1 is -78°C to 100°C, and the t1 is 0.5h-36h.

[0045] In an optional embodiment, the T2 is -78°C to 50°C, and the t2 is 0.5h-36h.

[0046] In an optional embodiment, the molar ratio of the compound iii to the second hydrogen removal agent is 1:2.0-3.0.

[0047] In an optional embodiment, the molar ratio of the compound iii to the metal M salt or metal M organic compound is 1:1.0-1.5.

[0048] In an optional embodiment, the T3 is -78°C to 100°C, and the t3 is 0.5h-36h.

[0049] In an optional embodiment, the T4 is -78°C to 50°C, and the t4 is 0.5h-36h.

[0050] The above process conditions can ensure the smooth progress of the reaction, while also inhibiting the generation of by-products and ensuring the yield of the target compound.

[0051] In a third aspect, the present application further provides a metallocene catalyst, comprising a main catalyst and a co-catalyst, wherein the co-catalyst comprises organic aluminum and / or organic boron; the main catalyst is the metallocene compound described in the first aspect or the metallocene compound prepared by the preparation method described in the second aspect.

[0052] In an optional embodiment, the molar ratio of the Al element in the organic aluminum to the M element in the metallocene compound is 2-600.

[0053] Further optionally, the molar ratio of the Al element in the organic aluminum to the M element in the metallocene compound is 10-100.

[0054] In an optional embodiment, the molar ratio of the B element in the organic boron to the M element in the metallocene compound is 0-80.

[0055] Further optionally, the molar ratio of the B element in the organic boron to the M element in the metallocene compound is 0-20.

[0056] In an optional embodiment, the organic aluminum is selected from at least one of aluminoxane, alkyl aluminum, and alkyl aluminum chloride. Specifically, the aluminoxane includes at least one of methyl aluminoxane, modified methyl aluminoxane, ethyl aluminoxane, n-propyl aluminoxane, isopropyl aluminoxane, n-butyl aluminoxane, isobutyl aluminoxane, neopentyl aluminoxane, n-hexyl aluminoxane, and n-octyl aluminoxane; the modified methyl aluminoxane includes at least one of ethyl aluminum modified methyl aluminoxane, butyl aluminum modified methyl aluminoxane, and octyl aluminum modified methyl aluminoxane; the alkyl aluminum includes trimethyl aluminum, triethyl aluminum, tri-n-butyl aluminum, and tri-n-butyl aluminum. At least one of propylaluminum, triisopropylaluminum, tri-n-butylaluminum, triisobutylaluminum, tri-n-hexylaluminum, triisohexylaluminum, tri-n-octylaluminum, and triisooctylaluminum; the alkylaluminum chloride includes at least one of dimethylaluminum chloride, diethylaluminum chloride, di-n-butylaluminum chloride, diisobutylaluminum chloride, n-butylaluminum dichloride, isobutylaluminum dichloride, sesqui-n-butylaluminum chloride, sesquiethylaluminum chloride, sesquimethylaluminum chloride, and sesquiisobutylaluminum chloride.

[0057] In an optional embodiment, the organic boron is selected from at least one of tris(pentafluorophenyl)boron, trityltetrakis(pentafluorophenyl)borate, triphenylmethyltetrakis(pentafluorophenyl)borate, triphenylformiumtetrakis(pentafluorophenyl)borate, tetrakis(pentafluorophenyl)boric acid-methyldi-(octadecyl)ammonium salt, N,N-dioctadecylmethylaminotetrakis(pentafluorophenyl)borate, N,N-dimethylaniliniumtetrakis(pentafluorophenyl)borate, dioctadecylmethyltertiaryammoniumtetrakis(pentafluorophenyl)borate, and dihydrogenated tallow methyltertiaryammoniumtetrakis(pentafluorophenyl)borate.

[0058] In a fourth aspect, the present application provides use of the metallocene catalyst described in the third aspect in the production of polyolefins.

[0059] In a fifth aspect, the present application also provides a method for preparing an ethylene / α-olefin copolymer, comprising the following steps:

[0060] In the presence of the metallocene catalyst described in the fourth aspect, ethylene and α-olefin are polymerized in an organic solvent to prepare an ethylene / α-olefin copolymer.

[0061] In an optional embodiment, the polymerization reaction temperature is 40° C.-260° C., and the polymerization reaction gauge pressure is 0.1 MPa-60 MPa.

[0062] Further optionally, the polymerization reaction temperature is 80° C.-230° C., and the polymerization reaction gauge pressure is 1 MPa-10 MPa.

[0063] In an optional embodiment, the amount of the metallocene catalyst added is 0.01 μmol / L-7 μmol / L, calculated as the molar concentration of the M element in the organic solvent.

[0064] In an optional embodiment, the α-olefin is selected from at least one of propylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-heptene, 1-octene, 1-decene, 1-undecene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, cyclopentene, cyclohexene, norbornene, phenylnorbornene, and styrene.

[0065] In an optional embodiment, the organic solvent is selected from at least one of aromatic hydrocarbons and alkane organic solvents, for example, it can be C8 isoalkane, isohexane (Isohexanes), 2-methyl-2-propanol (Isopar E), methylcyclohexane, toluene, etc.

[0066] Additional aspects and advantages of the embodiments of the present application will be described and shown in part in the subsequent description, or explained through the implementation of the embodiments of the present application. DETAILED DESCRIPTION

[0067] The technical solutions in the embodiments of the present application are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present application.

[0068] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" in the description and claims of this application and any variations thereof are intended to cover non-exclusive inclusions.

[0069] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0070] "Scope" disclosed in the present application is limited in the form of lower limit and upper limit, and a given range is limited by selecting a lower limit and an upper limit, and the selected lower limit and upper limit define the boundary of a special range. The scope limited in this way can be including end values ​​or not including end values, and can be arbitrarily combined, that is, any lower limit can be combined with any upper limit to form a scope. For example, if the scope of 60-120 and 80-110 is listed for a specific parameter, it is understood that the scope of 60-110 and 80-120 is also expected. In addition, if the minimum range values ​​1 and 2 are listed, and if the maximum range values ​​3, 4 and 5 are listed, the following scope can be all expected: 1-3, 1-4, 1-5, 2-3, 2-4 and 2-5. In the present application, unless otherwise specified, the numerical range "ab" represents the abbreviation of any real number combination between a and b, wherein a and b are real numbers. For example, the numerical range "0-5" means that all real numbers between "0-5" are listed in this document, and "0-5" is just an abbreviation of these numerical combinations. In addition, when a parameter is expressed as an integer ≥ 2, it is equivalent to disclosing that the parameter is, for example, an integer of 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0071] In the description of the embodiments of the present application, the term "and / or" is only a description of the association relationship of the associated objects, indicating that there may be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0072] The present application is further described in detail below in conjunction with specific examples, which should not be construed as limiting the scope of protection claimed in the present application. The materials and reagents used in the following examples were purchased from commercial sources, including:

[0073] Toluene: AR, aladdin;

[0074] n-Butyl lithium: AR, Innochem;

[0075] Compounds i-1 to i10: AR, Innochem;

[0076] Compounds ii-1~ii10: AR, Innochem;

[0077] ZrCl4: Tokyo Chemical Industry Co., Ltd.;

[0078] HfCl4: Tokyo Chemical Industry Co., Ltd.;

[0079] ZrMe4: Tokyo Chemical Industry Co., Ltd.;

[0080] ZrBn4: Tokyo Chemical Industry Co., Ltd.;

[0081] Methylaluminoxane (MAO): Albemarle;

[0082] Modified methylaluminoxane (MMAO): Albemarle;

[0083] Trimethylaluminum (Me3Al): AR, Aladdin;

[0084] Ethyl aluminum dichloride: AR, Aladdin;

[0085] Trityl tetrakis(pentafluorophenyl)borate: AR, Aladdin;

[0086] Ethylene: 99.9%, Beijing Yanshan Petrochemical Company;

[0087] 1-Hexene: 98%, Beijing Yanshan Petrochemical Company;

[0088] 1-Octene: 98%, Beijing Yanshan Petrochemical Company;

[0089] Cyclohexene: 98%, Beijing Yanshan Petrochemical Company;

[0090] Phenyl norbornene: 98%, Beijing Yanshan Petrochemical Company;

[0091] Styrene: 98%, Beijing Yanshan Petrochemical Company;

[0092] Isopar E: ExxonMobil Corporation.

[0093] Unless otherwise specified, the experimental methods used in the following examples are conventional methods.

[0094] The compounds in the following examples were characterized by nuclear magnetic resonance (Brucker ARX-400).

[0095] The following examples and comparative examples are calculated according to the following formula:

[0096] Polymerization activity = polymer mass / (metal content in catalyst × polymerization time).

[0097] The weight average molecular weight (Mw) of the polymer was measured by PL-GPC220 at 160°C.

[0098] The calculation method of the comonomer insertion rate is referred to the literature (Macromolecules 1999, 32, 3817). In all the following examples and comparative examples, the chemical reactions involved were carried out after nitrogen substitution. The following examples 1-10 are used to prepare different metallocene compounds:

[0099] Example 1

[0100]

[0101] 1) Add 5 g of compound i-1 and 4.36 ml of n-butyl lithium n-hexane solution (2.5 M) to ultra-dry toluene in a molar ratio of 1:1.2, react at -78 ° C for 3 h, then add 3.46 g of compound ii-1 to react, ensuring that the molar ratio of compound i-1 to compound ii-1 is 1:1.1, and control the reaction temperature to 25 ° C, the reaction time to 5 h, after the reaction is completed, add ethanol to the reaction solution, stir to obtain a suspension, filter, wash and dry to obtain intermediate iii-1;

[0102] 2) Add 3 g of intermediate iii-1 and 1.6 ml of n-butyl lithium in n-hexane solution (2.5 M) to ultra-dry toluene in a molar ratio of 1:2.2, react at -78 ° C. for 24 h, slowly raise the temperature to 25 ° C., and then add 0.5 g of tetramethyl zirconium to react, ensuring that the molar ratio of intermediate iii-1 to tetramethyl zirconium is 1:1, control the reaction temperature to 25 ° C., and the reaction time is 24 h. After the reaction is completed, filter, concentrate, pulp, and dry the reaction solution to obtain the metallocene compound P7.

[0103] P7 NMR data: 1 H NMR(500MHz,Chloroform)δ7.84(s,2H),7.68(s,2H),7.32(d,J=36.5Hz,6H),6.85(s,4H),3.86(s,8H),3.79(s,6H),2.83(s,4H ),2.71(s,4H),2.23(d,J=17.2Hz,6H),2.04(d,J=19.0Hz,4H),1.80(s,4H),1.65(d,J=5.0Hz,12H),0.81(s,4H),-0.25(s,6H).

[0104] Example 2

[0105]

[0106] 1) Add 5 g of compound i-2 and 4.36 ml of n-butyl lithium in n-hexane solution (2.5 M) to ultra-dry toluene in a molar ratio of 1:1.2, react at -78 ° C for 3 h, then add 3.64 g of compound ii-2 to react, ensuring that the molar ratio of compound i-2 to compound ii-2 is 1:1.1, and control the reaction temperature to 25 ° C, the reaction time to 5 h, after the reaction is completed, add ethanol to the reaction solution, stir to obtain a suspension, filter, wash and dry to obtain intermediate iii-2;

[0107] 2) Add 3 g of intermediate iii-2 and 3 ml of n-butyl lithium in n-hexane solution (2.5 M) to ultra-dry toluene in a molar ratio of 1:2.2, react at -78 ° C. for 24 h, slowly raise the temperature to 25 ° C., and then add 0.51 g of tetramethyl zirconium to react, ensuring that the molar ratio of intermediate iii-2 to tetramethyl zirconium is 1:1, control the reaction temperature to 25 ° C., and the reaction time is 24 h. After the reaction is completed, filter, concentrate, pulp, and dry the reaction solution to obtain metallocene compound P8.

[0108] P8 NMR data: 1H NMR(500MHz,Chloroform)δ7.88(s,2H),7.70(s,2H),7.33(s,2H),7.28(s,4H),7.23(d,J =10.0Hz,6H),6.15(s,1H),5.90(s,1H),4.33(s,1H),3.86(s,8H),2.85(s,4H),2.71(s,4H ),2.65(s,1H),2.25(s,4H),2.20(s,2H),2.02(d,J=19.0Hz,4H),1.81(d,J=3.2Hz,6H),1. 60(s,1H),1.50(s,2H),1.37(s,2H),1.20(s,2H),1.12(s,1H),0.81(s,4H),-0.25(s,6H).

[0109] Example 3

[0110]

[0111] 1) Add 5 g of compound i-3 and 4.36 ml of n-butyl lithium in n-hexane solution (2.5 M) to ultra-dry toluene in a molar ratio of 1:1.2, react at -78 ° C for 3 h, then add 2.28 g of compound ii-3 to react, ensuring that the molar ratio of compound i-3 to compound ii-3 is 1:1.1, and control the reaction temperature to 25 ° C, the reaction time to 5 h, after the reaction is completed, add ethanol to the reaction solution, stir to obtain a suspension, filter, wash and dry to obtain intermediate iii-3;

[0112] 2) Add 3 g of intermediate iii-3 and 3.55 ml of n-butyl lithium in n-hexane solution (2.5 M) to ultra-dry toluene in a molar ratio of 1:2.2, react at -78 ° C. for 24 h, slowly raise the temperature to 25 ° C., and then add 0.61 g of tetramethyl zirconium to react, ensuring that the molar ratio of intermediate iii-3 to tetramethyl zirconium is 1:1, control the reaction temperature to 25 ° C., and the reaction time is 24 h. After the reaction is completed, the reaction solution is filtered, concentrated, pulped, and dried to obtain the metallocene compound P9.

[0113] P9's NMR data: 1H NMR(500MHz,Chloroform)δ7.94(d,2H),7.67(d,2H),7.36(d,2H),6.28-6.21(m,2H),5.81(d,2H),5.50(s,2H),3.86(s,8H),2.77-2.69(m,4H),2.2 7-2.17(m,8H),2.15(s,2H),2.06(d,J=19.0Hz,4H),1.83(d,J=15.3Hz,6H ),1.49-1.33(m,2H),0.95(s,4H),0.65(s,6H),0.25(s,4H),-0.2(m,6H).

[0114] Example 4

[0115]

[0116] 1) Add 5 g of compound i-4 and 4.36 ml of n-butyl lithium in n-hexane solution (2.5 M) to ultra-dry toluene in a molar ratio of 1:1.2, react at -78 ° C for 3 h, then add 1.9 g of compound ii-4 to react, ensuring that the molar ratio of compound i-4 to compound ii-4 is 1:1.1, and control the reaction temperature to 25 ° C, the reaction time to 5 h, after the reaction is completed, add ethanol to the reaction solution, stir to obtain a suspension, filter, wash and dry to obtain intermediate iii-4;

[0117] 2) Add 3 g of intermediate iii-4 and 3.56 ml of n-butyl lithium in n-hexane solution (2.5 M) to ultra-dry toluene in a molar ratio of 1:2.2, react at -78 ° C. for 24 h, slowly raise the temperature to 25 ° C., and then add 1.85 g of tetrabenzyl zirconium to react, ensuring that the molar ratio of intermediate iii-4 to tetrabenzyl zirconium is 1:1, control the reaction temperature to 25 ° C., and the reaction time is 24 h. After the reaction is completed, filter, concentrate, pulp and dry the reaction solution to obtain the metallocene compound P22.

[0118] P22's NMR data: 1H NMR(500MHz,Chloroform)δ7.91(d,2H),7.68(d,2H),7.41(d,2H),7.23(d,J=5.0Hz,8H),7.19(s,1H),4.28(s,1H),3.86(s,8H),2.88(d,4H) ,2.76-2.72(m,3H),2.65(s,4H),2.28-2.20(m,6H),1.85(d,4H),1.65 (d,J=5.0Hz,12H),1.59-1.31(m,8H),1.06(s,3H),0.84-0.79(m,8H).

[0119] Example 5

[0120]

[0121] 1) Add 5 g of compound i-5 and 4.15 ml of n-butyl lithium in n-hexane solution (2.5 M) to ultra-dry toluene in a molar ratio of 1:1.2, react at -78 ° C for 3 h, then add 4.27 g of compound ii-5 to react, ensuring that the molar ratio of compound i-5 to compound ii-5 is 1:1.1, and control the reaction temperature to 25 ° C, the reaction time to 5 h, after the reaction is completed, add ethanol to the reaction solution, stir to obtain a suspension, filter, wash and dry to obtain intermediate iii-5;

[0122] 2) Add 3 g of intermediate iii-5 and 2.66 ml of n-butyl lithium in n-hexane solution (2.5 M) to ultra-dry toluene in a molar ratio of 1:2.2, react at -78 ° C. for 24 h, slowly raise the temperature to 25 ° C., and then add 0.97 g of hafnium tetrachloride to react, ensuring that the molar ratio of intermediate iii-5 to hafnium tetrachloride is 1:1, control the reaction temperature to 25 ° C., and the reaction time is 24 h. After the reaction is completed, filter, concentrate, pulp, and dry the reaction solution to obtain metallocene compound P35.

[0123] P35 NMR data: 1 H NMR(500MHz,Chloroform)δ8.69(s,2H),7.95(s,2H),7.75(s,4H),7.59-7.32(m,17H),6.39(s,1H),5.96(s,1H),4.81(s,2H),3.86(d,J=5 0.0Hz,8H),3.49(s,1H),2.28(s,4H),2.17(d,J=3.0Hz,4H),2.15-1.98(m,12H),1.81(d,J=1.0Hz,4H),1.66(d,J=5.0Hz,4H),1.05(s,2H).

[0124] Example 6

[0125]

[0126] 1) Add 5 g of compound i-6 and 4.87 ml of n-butyl lithium in n-hexane solution (2.5 M) to ultra-dry toluene in a molar ratio of 1:1.2, react at -78 ° C for 3 h, then add 1.18 g of compound ii-6 to react, ensuring that the molar ratio of compound i-6 to compound ii-6 is 1:1.1, and control the reaction temperature to 25 ° C, the reaction time to 5 h, after the reaction is completed, add ethanol to the reaction solution, stir to obtain a suspension, filter, wash and dry to obtain intermediate iii-6;

[0127] 2) Add 3 g of intermediate iii-6 and 4.41 ml of n-butyl lithium in n-hexane solution (2.5 M) to ultra-dry toluene in a molar ratio of 1:2.2, react at -78 ° C. for 24 h, slowly raise the temperature to 25 ° C., and then add 1.6 g of hafnium tetrachloride to react, ensuring that the molar ratio of intermediate iii-6 to hafnium tetrachloride is 1:1, control the reaction temperature to 25 ° C., and the reaction time is 24 h. After the reaction is completed, filter, concentrate, pulp, and dry the reaction solution to obtain metallocene compound P40.

[0128] P40 NMR data: 1 H NMR(500MHz,Chloroform)δ8.11(s,2H),7.37(s,2H),6.84(d,2H),6.33(d,1H),6.16-5.95(m ,2H),3.31(t,1H),3.02(s,2H),2.18(s,14H),2.16–2.11(m,6H),1.71(t,14H),1.01(s,6H).

[0129] Example 7

[0130]

[0131] 1) Add 5 g of compound i-7 and 2.25 ml of n-butyl lithium in n-hexane solution (2.5 M) to ultra-dry toluene in a molar ratio of 1:1.2, react at -78 ° C for 3 h, then add 5.37 g of compound ii-7 to react, ensuring that the molar ratio of compound i-7 to compound ii-7 is 1:1.1, and control the reaction temperature to 25 ° C, the reaction time to 5 h, after the reaction is completed, add ethanol to the reaction solution, stir to obtain a suspension, filter, wash and dry to obtain intermediate iii-7;

[0132] 2) Add 3 g of intermediate iii-7 and 3.07 ml of n-butyl lithium in n-hexane solution (2.5 M) to ultra-dry toluene in a molar ratio of 1:2.2, react at -78 ° C. for 24 h, slowly raise the temperature to 25 ° C., and then add 0.81 g of zirconium tetrachloride to react, ensuring that the molar ratio of intermediate iii-7 to zirconium tetrachloride is 1:1, control the reaction temperature to 25 ° C., and the reaction time is 24 h. After the reaction is completed, the reaction solution is filtered, concentrated, pulped, and dried to obtain the metallocene compound P49.

[0133] P49 NMR data: 1 H NMR(500MHz,Chloroform)δ8.64(s,2H),7.92(s,2H),7.34(d,J=13.7Hz,6H),7.16(s,4H),6.29(s,2H),5.39(s,2H),4.16(s,2H),3.69( s,2H),3.29(s,2H),2.75(s,2H),2.00(d,J=15.0Hz,12H),1.81(s,2H),1.72(s,12H),1.60(s,2H),1.33(s,18H),1.16(d,J=40.0Hz,4H).

[0134] Example 8

[0135]

[0136] 1) Add 5 g of compound i-8 and 3.13 ml of n-butyl lithium in n-hexane solution (2.5 M) to ultra-dry toluene in a molar ratio of 1:1.2, react at -78 ° C for 3 h, then add 3.21 g of compound ii-8 to react, ensuring that the molar ratio of compound i-8 to compound ii-8 is 1:1.1, and control the reaction temperature to 25 ° C, the reaction time to 5 h, after the reaction is completed, add ethanol to the reaction solution, stir to obtain a suspension, filter, wash and dry to obtain intermediate iii-8;

[0137] 2) Add 3 g of intermediate iii-8 and 2.17 ml of n-butyl lithium in n-hexane solution (2.5 M) to ultra-dry toluene in a molar ratio of 1:2.2, react at -78 ° C. for 24 h, slowly raise the temperature to 25 ° C., and then add 0.58 g of zirconium tetrachloride to react, ensuring that the molar ratio of intermediate iii-8 to zirconium tetrachloride is 1:1, control the reaction temperature to 25 ° C., and the reaction time is 24 h. After the reaction is completed, the reaction solution is filtered, concentrated, pulped, and dried to obtain the metallocene compound P54.

[0138] P54 NMR data: 1H NMR(500MHz,Chloroform)δ7.50(s,4H),6.58(d,J=23.0Hz,4H),6.00(s,4H),3.5 5(s,4H),1.99(s,12H),1.65-1.85(m,48H),1.59–1.38(m,8H),1.15-1.31(m,4H).

[0139] Example 9

[0140]

[0141] 1) Add 5 g of compound i-9 and 5.52 ml of n-butyl lithium in n-hexane solution (2.5 M) to ultra-dry toluene in a molar ratio of 1:1.2, react at -78 ° C for 3 h, then add 2.91 g of compound ii-9 to react, ensuring that the molar ratio of compound i-9 to compound ii-9 is 1:1.1, and control the reaction temperature to 25 ° C, the reaction time to 5 h, after the reaction is completed, add ethanol to the reaction solution, stir to obtain a suspension, filter, wash and dry to obtain intermediate iii-9;

[0142] 2) Add 3 g of intermediate iii-9 and 3.97 ml of n-butyl lithium in n-hexane solution (2.5 M) to ultra-dry toluene in a molar ratio of 1:2.2, react at -78 ° C for 24 hours, slowly raise the temperature to 25 ° C, and then add 1.04 g of zirconium tetrachloride to react, ensuring that the molar ratio of intermediate iii-9 to zirconium tetrachloride is 1:1, control the reaction temperature to 25 ° C, the reaction time is 24 hours, after the reaction is completed, filter the reaction solution, concentrate, pulp, and dry to obtain the metallocene compound P62.

[0143] P62 NMR data: 1 H NMR(500MHz,Chloroform)δ8.10(s,2H),8.01(s,2H),7.93(s,2H),7.65(s,2H),7.49(s,2H),7.40(s,2H),7.33( t,J=15.0Hz,10H),6.38(s,2H),6.31(s,2H),5.71(s,2H),4.45(s,2H),2.00(s,6H),1.70(s,12H),1.61(s,12H).

[0144] Example 10

[0145]

[0146] 1) Add 5 g of compound i-10 and 5.14 ml of n-butyl lithium in n-hexane solution (2.5 M) to ultra-dry toluene in a molar ratio of 1:1.2, react at -78 ° C for 3 h, then add 2.74 g of compound ii-10 to react, ensuring that the molar ratio of compound i-10 to compound ii-10 is 1:1.1, and control the reaction temperature to 25 ° C, the reaction time to 5 h, after the reaction is completed, add ethanol to the reaction solution, stir to obtain a suspension, filter, wash and dry to obtain intermediate iii-10;

[0147] 2) Add 3 g of intermediate iii-10 and 3.78 ml of n-butyl lithium in n-hexane solution (2.5 M) to ultra-dry toluene in a molar ratio of 1:2.2, react at -78 ° C for 24 hours, slowly raise the temperature to 25 ° C, and then add 0.99 g of zirconium tetrachloride to react, ensuring that the molar ratio of intermediate iii-10 to zirconium tetrachloride is 1:1, control the reaction temperature to 25 ° C, the reaction time is 24 hours, after the reaction is completed, filter the reaction solution, concentrate, pulp, and dry to obtain metallocene compound P97.

[0148] P97's NMR data: 1 H NMR(500MHz,Chloroform)δ8.06(d,J=3.1Hz,1H),7.97(d,J=70.3Hz,2H),7.84(s,1H),7.39-7.29(m,2H),7.24(t,1H),5.95(d,2H) ,5.65(d,2H),2.74(s,2H),2.01-1.97(m,4H),1.71(t,12H),1.62(d,12H),1.55(s,2H),1.43-1.39(m,2H),0.94(d,J=5.0Hz,20H).

[0149] Embodiment 11

[0150] A method for preparing an ethylene / hexene copolymer comprises the following steps:

[0151] To 200 mL of Isopar E solvent, 1 μmol of the metallocene compound P7 prepared in Example 1, 80 ml of 1-hexene and MMAO at a molar ratio of Al / M=50 were added, the temperature was raised to 140° C., 4 MPa of ethylene gas was introduced, and the polymerization reaction was carried out for 5 minutes. After the reaction was completed, the ethylene was vented, and the reaction liquid was discharged into ethanol. The precipitate was collected and dried to obtain an ethylene / hexene copolymer.

[0152] Example 12

[0153] An ethylene / hexene copolymer was prepared according to the method provided in Example 11, the only difference being that the metallocene compound P8 prepared in Example 2 was used instead of the metallocene compound P7.

[0154] Example 13

[0155] An ethylene / hexene copolymer was prepared according to the method provided in Example 11, the only difference being that the metallocene compound P9 prepared in Example 3 was used instead of the metallocene compound P7.

[0156] Embodiment 14

[0157] An ethylene / hexene copolymer was prepared according to the method provided in Example 11, the only difference being that the metallocene compound P22 prepared in Example 4 was used instead of the metallocene compound P7.

[0158] Embodiment 15

[0159] An ethylene / hexene copolymer was prepared according to the method provided in Example 11, the only difference being that the metallocene compound P35 prepared in Example 5 was used instead of the metallocene compound P7.

[0160] Example 16

[0161] An ethylene / hexene copolymer was prepared according to the method provided in Example 11, the only difference being that the metallocene compound P40 prepared in Example 6 was used instead of the metallocene compound P7.

[0162] Embodiment 17

[0163] An ethylene / hexene copolymer was prepared according to the method provided in Example 11, the only difference being that the metallocene compound P49 prepared in Example 7 was used instead of the metallocene compound P7.

[0164] Embodiment 18

[0165] An ethylene / hexene copolymer was prepared according to the method provided in Example 11, the only difference being that the metallocene compound P54 prepared in Example 8 was used instead of the metallocene compound P7.

[0166] Embodiment 19

[0167] An ethylene / hexene copolymer was prepared according to the method provided in Example 11, the only difference being that the metallocene compound P62 prepared in Example 9 was used instead of the metallocene compound P7.

[0168] Embodiment 20

[0169] An ethylene / hexene copolymer was prepared according to the method provided in Example 11, the only difference being that the metallocene compound P97 prepared in Example 10 was used instead of the metallocene compound P7.

[0170] Embodiment 21

[0171] A method for preparing an ethylene / octene copolymer comprises the following steps:

[0172] To 200 mL of Isopar E solvent were added 1 μmol of the metallocene compound P62 obtained in Example 9, 50 ml of 1-octene, MMAO at a molar ratio of Al / M=20, and trityltetrakis(pentafluorophenyl)borate at a molar ratio of B / M=0.5. The temperature was raised to 140° C., 4 MPa of ethylene gas was introduced, and the polymerization reaction was carried out for 5 min. After the reaction was completed, the ethylene was vented, and the reaction solution was discharged into ethanol. The precipitate was collected and dried to obtain an ethylene / octene copolymer.

[0173] Embodiment 22

[0174] A method for preparing an ethylene / cyclohexene copolymer comprises the following steps:

[0175] To 200 mL of Isopar E solvent, 1 μmol of the metallocene compound P62 prepared in Example 9, 90 ml of cyclohexene and MAO at a molar ratio of Al / M=40 were added, the temperature was raised to 200° C., 4 MPa of ethylene gas was introduced, and the polymerization reaction was carried out for 5 minutes. After the reaction was completed, the ethylene was vented, the reaction liquid was discharged into ethanol, the precipitate was collected, and dried to obtain an ethylene / cyclohexene copolymer.

[0176] Embodiment 23

[0177] A method for preparing an ethylene / phenyl norbornene copolymer comprises the following steps:

[0178] To 200 mL of Isopar E solvent were added 1 μmol of the metallocene compound P62 obtained in Example 9, 90 ml of phenyl norbornene, ethylaluminum dichloride at a molar ratio of Al / M=20, and trityltetrakis(pentafluorophenyl)borate at a molar ratio of B / M=1. The temperature was raised to 90° C., 4 MPa of ethylene gas was introduced, and the polymerization reaction was carried out for 5 min. After the reaction was completed, the ethylene was vented, and the reaction solution was discharged into ethanol. The precipitate was collected and dried to obtain an ethylene / phenyl norbornene copolymer.

[0179] Embodiment 24

[0180] A method for preparing an ethylene / styrene copolymer comprises the following steps:

[0181] To 200 mL of Isopar E solvent were added 1 μmol of the metallocene compound P62 obtained in Example 9, 90 ml of styrene, triisobutylaluminum at a molar ratio of Al / M=10, and trityltetrakis(pentafluorophenyl)borate at a molar ratio of B / M=2. The temperature was raised to 170° C., 4 MPa of ethylene gas was introduced, and the polymerization reaction was carried out for 5 min. After the reaction was completed, the ethylene was vented, and the reaction solution was discharged into ethanol. The precipitate was collected and dried to obtain an ethylene / styrene copolymer.

[0182] Comparative Example 1

[0183] Ethylene / hexene copolymer was prepared according to the method provided in Example 19, the only difference being that the compound shown in formula II-1 was used instead of the metallocene compound P62.

[0184]

[0185] Comparative Example 2

[0186] An ethylene / hexene copolymer was prepared according to the method provided in Example 19, except that the Al / M molar ratio was 1000 and compound II-1 was used instead of metallocene compound P62.

[0187] Comparative Example 3

[0188] An ethylene / octene copolymer was prepared according to the method provided in Example 21, the only difference being that compound II-1 was used instead of metallocene compound P62.

[0189] Comparative Example 4

[0190] An ethylene / styrene copolymer was prepared according to the method provided in Example 24, except that compound II-1 was used instead of metallocene compound P62.

[0191] Comparative Example 5

[0192] Ethylene / styrene copolymer was prepared according to the method provided in Example 24, the only difference being that the B / M molar ratio was 200 and compound II-1 was used instead of metallocene compound P62.

[0193] Test Case

[0194] The performance tests were conducted on the amounts of co-catalysts used and the prepared polyolefins in the above Examples 11-24 and Comparative Examples 1-5. The results are shown in Table 1 below.

[0195] Table 1

[0196]

[0197] As can be seen from Table 1, the polymers prepared in Examples 11-24 exhibit high polymerization activity and comonomer insertion rate, which indicates that the metallocene catalyst of the present application has good catalytic activity for the polymerization reaction of α-olefins and good copolymerization performance. Compared with Examples 19, 21 and 24, the polymerization effects of Comparative Examples 1, 3 and 4 are poor, further indicating that the introduction of adamantane groups into the metallocene catalyst can significantly improve the catalytic activity of the metallocene catalyst.

[0198] In order to obtain a catalytic effect basically equivalent to that of Example 19, Comparative Example 2 needs to use a larger amount of co-catalyst when using Compound II-1 as the main catalyst. However, even if a large amount of co-catalyst is added when using Compound II-1 as the main catalyst in Comparative Example 5, the catalytic effect of Example 24 cannot be achieved. This shows that the use of the metallocene catalyst of the present application can reduce the amount of co-catalyst, which can not only reduce the production cost of polyolefins, but more importantly, it can also avoid affecting the quality of polyolefins due to excessive co-catalyst residues, thereby expanding the applicable scenarios of the product.

[0199] The above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the scope of protection created by this application.

Claims

1. A metallocene compound, the chemical structure of which includes a fluorenyl ligand, a metallocene ligand, a bridging structure and a metal part; characterized in that: The metallocene compound has a structure shown in formula (I): wherein A1, A2, A3, and A4 are each independently selected from H or an adsorption group, and at least one of A1-A4 is selected from an adsorption group, and the adsorption group is a bulky group that can adsorb organic boron or organic aluminum; R1, R2, R3, R4, R5, and R6 are each independently selected from H, halogen, and a substituted or unsubstituted G group, wherein the G group includes C1-C 40 Alkyl, C3-C 40 Cycloalkyl, C2-C 40 Heterocycloalkyl, C6-C 60 Aryl, C4-C 60 Heteroaryl, C7-C 60 Aralkyl, C6-C 60 Any one of the heteroarylalkyl groups; L is selected from C, Si, Ge or Sn; M is selected from Ti, Zr or Hf; X is selected from halogen, substituted or unsubstituted Y group, the Y group includes C1-C 30 Alkyl, C3-C 30 Cycloalkyl, C2-C 30 Heterocycloalkyl, C2-C 20 Unsaturated hydrocarbon groups, C6-C 30 Aryl, C4-C 30 Heteroaryl, C5-C 30 Aralkyl, C5-C 30 Any one of the heteroarylalkyl groups; The halogen is at least one of F, Cl, Br and I.

2. The metallocene compound according to claim 1, characterized in that The adsorption group is selected from adamantyl or a derivative of adamantyl, wherein the derivative of adamantyl includes a Q group and at least one adamantyl group, wherein the Q group shares a carbon atom with the adamantyl group or the Q group is connected to the adamantyl group via a covalent bond; wherein the Q group is selected from a heteroatom, a T group, a halogen-substituted T group or a T group containing a heteroatom, wherein the T group includes C1-C 20 Alkyl, C2-C 20 Cycloalkyl, C4-C 30 Aryl, C5-C 30 At least one of the arylalkyl groups, wherein the heteroatom is selected from at least one of O, N, P, S, Si, and Ge; And / or, the G group includes C1-C 10 Alkyl, C3-C 10 Cycloalkyl, C2-C6 heterocycloalkyl, C6-C 15 Aryl, C4-C 15 Heteroaryl, C7-C 15 Aralkyl, C6-C 15 Any one of the heteroarylalkyl groups; and / or, the substituent in the substituted G group is selected from any one of halogen, C1-C5 alkyl, C1-C5 alkoxy, and C1-C5 haloalkyl; And / or, the Y group includes a C1-C5 alkyl group, a C3-C 10 Cycloalkyl, C2-C6 heterocycloalkyl, C2-C 10 Unsaturated hydrocarbon groups, C6-C 15 Aryl, C4-C 15 Heteroaryl, C7-C 15 Aralkyl, C6-C 15 Any one of the heteroarylalkyl groups; And / or, the substituent in the substituted Y group is selected from any one of halogen, C1-C5 alkyl, C1-C5 alkoxy, and C1-C5 haloalkyl.

3. The metallocene compound according to claim 2, characterized in that The adamantyl derivative is connected to the fluorenyl group via the adamantyl group or the Q group, and the adamantyl derivative is selected from any one of adamantyl substituted with a C1-C5 alkyl group, adamantyl substituted with a C2-C5 heterocycloalkyl group, a spirocyclic group formed by a C2-C5 heterocycloalkyl group and an adamantyl group, an adamantyl substituted amine group, an adamantyl substituted alkyl group, and an adamantyl substituted phosphino group; and / or, the substituted or unsubstituted G group includes any one of methyl, ethyl, propyl, tert-butyl, cyclohexyl, phenyl, methylphenyl, methoxyphenyl, fluorophenyl, trifluoromethylphenyl, tert-butylphenyl, and biphenyl; And / or, the substituted or unsubstituted Y group includes any one of a methyl group and a benzyl group.

4. The metallocene compound according to any one of claims 1 to 3, characterized in that The fluorenyl ligand is selected from any one of the following structures: And / or, the carbonyl ligand is selected from any one of the following structures: And / or, the bridging structure is selected from any one of the following structures:

5. The metallocene compound according to claim 4, characterized in that The metallocene compound is selected from any one of the following structures:

6. The method for preparing the metallocene compound according to any one of claims 1 to 5, characterized in that: The steps include: 1) In a first organic solvent, compound i is reacted with a first hydrogen extraction agent at a reaction temperature of T1 and a reaction time of t1; then compound ii is added to continue the reaction at a reaction temperature of T2 and a reaction time of t2 to obtain compound iii; 2) In a second organic solvent, compound iii is reacted with a second hydrogen extraction agent at a reaction temperature of T3 and a reaction time of t3; then a metal M salt or a metal M organic compound is added to continue the reaction at a reaction temperature of T4 and a reaction time of t4 to obtain a metallocene compound represented by formula I.

7. The method for preparing the metallocene compound according to claim 6, characterized in that: The first organic solvent and the second organic solvent are each independently selected from at least one of toluene, xylene, pentane, cyclopentane, n-hexane, cyclohexane, n-heptane, methylcyclohexane, octane, isooctane, and tetrahydrofuran; and / or, the first hydrogenation agent and the second hydrogenation agent are each independently selected from at least one of alkyl lithium, phenyl lithium, sodium hydride, potassium hydride, lithium hydride, tetramethylethylenediamine, lithium bistrimethylsilylamide, sodium bistrimethylsilylamide, lithium diisopropylamide, and potassium carbonate; And / or, the molar ratio of the compound i to the first hydrogen removal reagent is 1:1.0-1.5; And / or, the molar ratio of the compound i to the compound ii is 1:1.0-1.5; and / or, the T1 is -78°C to 100°C, and the t1 is 0.5h-36h; and / or, the T2 is -78°C to 50°C, and the t2 is 0.5h-36h; And / or, the molar ratio of the compound iii to the second hydrogenation reagent is 1:2.0-3.0; and / or, the molar ratio of the compound iii to the metal M salt or metal M organic compound is 1:1.0-1.5; and / or, the T3 is -78°C to 100°C, and the t3 is 0.5h-36h; And / or, the T4 is -78°C to 50°C, and the t4 is 0.5h-36h.

8. A metallocene catalyst comprising a main catalyst and a co-catalyst, wherein the co-catalyst comprises organic aluminum and / or organic boron; characterized in that: The main catalyst is the metallocene compound according to any one of claims 1 to 5 or the metallocene compound prepared by the preparation method according to claim 6 or 7; Optionally, the molar ratio of the Al element in the organic aluminum to the M element in the metallocene compound is 2-600, preferably 10-100; Optionally, the molar ratio of the B element in the organic boron to the M element in the metallocene compound is 0-80, preferably 0-20; Optionally, the organic aluminum is selected from at least one of aluminoxane, alkylaluminum, and alkylaluminum chloride; the aluminoxane includes at least one of methylaluminoxane, modified methylaluminoxane, ethylaluminoxane, n-propylaluminoxane, isopropylaluminoxane, n-butylaluminoxane, isobutylaluminoxane, neopentylaluminoxane, n-hexylaluminoxane, and n-octylaluminoxane; the alkylaluminum includes at least one of trimethylaluminum, triethylaluminum, tri-n-propylaluminum, triisopropylaluminum, tri-n-butylaluminum, triisobutylaluminum, tri-n-hexylaluminum, triisohexylaluminum, tri-n-octylaluminum, and triisooctylaluminum; the alkylaluminum chloride includes at least one of dichloromethylaluminum, dichloroethylaluminum, monochlorodimethylaluminum, monochlorodiethylaluminum, monochlorodi-n-butylaluminum, monochlorodiisobutylaluminum, dichloron-butylaluminum, dichloroisobutylaluminum, sesqui-n-butylaluminum chloride, sesquiethylaluminum chloride, sesquimethylaluminum chloride, and sesquiisobutylaluminum chloride; Optionally, the organic boron is selected from at least one of tris(pentafluorophenyl)boron, trityltetrakis(pentafluorophenyl)borate, triphenylmethyltetrakis(pentafluorophenyl)borate, triphenylformiumtetrakis(pentafluorophenyl)borate, tetrakis(pentafluorophenyl)boric acid-methyldi-(octadecyl)ammonium salt, N,N-dioctadecylmethylaminotetrakis(pentafluorophenyl)borate, N,N-dimethylaniliniumtetrakis(pentafluorophenyl)borate, dioctadecylmethyltertiaryammoniumtetrakis(pentafluorophenyl)borate, and dihydrogenated tallow methyltertiaryammoniumtetrakis(pentafluorophenyl)borate.

9. Use of the metallocene catalyst according to claim 8 in the production of polyolefins.

10. A method for preparing an ethylene / α-olefin copolymer, characterized in that: The steps include: In the presence of the metallocene catalyst according to claim 8, ethylene and α-olefin are polymerized in an organic solvent to prepare an ethylene / α-olefin copolymer; Optionally, the polymerization temperature is 40°C-260°C, preferably 80°C-230°C; Optionally, the polymerization reaction gauge pressure is 0.1MPa-60MPa, preferably 1MPa-10MPa; Optionally, the amount of the metallocene catalyst added is 0.01 μmol / L-7 μmol / L, based on the molar concentration of the M element in the organic solvent; Optionally, the α-olefin is selected from at least one of propylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-heptene, 1-octene, 1-decene, 1-undecene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, cyclopentene, cyclohexene, norbornene, phenylnorbornene, and styrene; Optionally, the organic solvent is selected from at least one of aromatic hydrocarbon and alkane organic solvents.

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