Preparation method of bridged metallocene compound, obtained bridged metallocene compound and application of bridged metallocene compound

Abstract

The invention discloses a preparation method of a bridged metallocene compound, the obtained bridged metallocene compound and application of the bridged metallocene compound. The preparation method comprises the following steps: (1) reacting fluorene and / or a derivative thereof with lithium alkylide in an organic solvent to obtain a reaction liquid I; (2) mixing the reaction liquid I with fulvene and / or a derivative thereof, and reacting to obtain a reaction liquid II; (3) mixing the reaction liquid II with lithium alkylide for reaction, and performing solid-liquid separation to obtain dilithium salt of the bridged metallocene compound ligand; and (4) mixing the dilithium salt of the bridged metallocene compound ligand with tetrahalide of IVB group metal for reaction, and performing post-treatment to obtain the bridged metallocene compound. The method has the characteristics of less reaction reagent consumption, less by-products, less solvent residue and high yield.

Description

Technical Field

[0001] The present invention belongs to the field of olefin catalysts, and in particular relates to a metallocene catalyst, and specifically relates to a preparation method of a bridged metallocene compound and the obtained bridged metallocene compound and application thereof. Background Art

[0002] Since the 1980s, metallocene catalysts have been rapidly developed as a new generation of polyolefin catalysts after Ziegler-Natta catalysts and chromium catalysts. As a single-site catalyst, metallocene catalysts can accurately control the reaction activity, molecular weight distribution of polyolefins, comonomer content and comonomer distribution. With the continuous growth of population and the continuous improvement of people's living standards, the demand for high-end polyolefin materials with high technical content, high application performance and high market value continues to expand. Compared with Ziegler-Natta catalyzed polyolefins, metallocene polyolefin products have the advantages of narrow molecular weight distribution, uniform comonomer distribution, excellent physical and mechanical properties, and good transparency. They are widely used in the fields of films, packaging, pipes, non-woven fabrics, etc. There are many types of metallocene polyolefin products developed worldwide, including metallocene metallocene polyethylene (mPE), metallocene polypropylene (mPP), polyolefin elastomer / plastomer (POE / POP), cyclic olefin copolymer (COC), etc. The development, production and application of metallocene catalysts are important directions in the field of polyolefins.

[0003] The introduction of a bridge group into a metallocene catalyst increases the rigidity of the metallocene compound. By adjusting the elements and chain length of the bridge group, the steric hindrance near the active center of the metallocene catalyst can be adjusted, and the activity, copolymerization performance and α-olefin stereoselectivity of the metallocene catalyst during olefin polymerization can be controlled. In 1993, Abbas Razavi and Jerry L. Atwood reported (η 5 -C5H4CPh2-η 5 -C 13H8) Synthesis and structural characterization of MCl2 (M is zirconium or hafnium), and its application in the synthesis of high molecular weight and high stereo isotacticity syndiotactic polypropylene. (J.Organomet.Chem.1993,459,117) In 2004, Stephen A.Miller and John E.Bercaw discussed the effect of remote ligand substituents on the stereo isotacticity of syndiotactic polypropylene. (Organometallics2004,23,1777) Jean-Francois Carpentier, Evgeny Kirillov and others studied the isotactic / syndiotactic problem of (Ph2C-(Flu)(3-Me3Si-Cp))ZrR2 prepolymerization catalyst for the synthesis of polypropylene. (Macromol.Chem.Phys.2014,215,2035) Beijing Research Institute of Chemical Industry reported in patent CN102464751 that (η 5 -C5H4CPh2-η 5 -C 13 H8) ZrCl2 in ethylene and C 1～18 Application in the synthesis of α-olefin copolymers. This type of bridged metallocene compound can be mainly used in high-end polyolefin products such as syndiotactic polypropylene, polyolefin elastomers / plastomers, cycloolefin copolymers, polar monomer copolymers, and polyα-olefins.

[0004] In some existing synthesis methods, the ligand is separated and purified before reacting with alkyl lithium, which increases the amount of alkyl lithium used. Before reacting with anhydrous zirconium tetrachloride, the dilithium salt of the ligand is not separated from the reaction system, which may make the molar ratio of zirconium tetrachloride to ligand inaccurate, resulting in waste of expensive zirconium tetrachloride, increased by-products, low product yield and dark color. Summary of the invention

[0005] In order to overcome the problems existing in the prior art, the present invention provides a method for preparing a bridged metallocene compound and the obtained bridged metallocene compound and application, wherein the method has the characteristics of less consumption of reaction reagents, less by-products, less solvent residue and high yield. Specifically, the use of butyl ether with a higher boiling point in the process of synthesizing the dilithium salt of the ligand is conducive to the reaction, and the yield is higher than that of ether and methyl tert-butyl ether, but because the boiling point of butyl ether is high, it is difficult to remove, and a large amount of solvents such as n-hexane need to be used for washing. The dilithium salt of the ligand is synthesized using butyl ether as a solvent, and after separating the dilithium salt of the ligand, it is reacted with anhydrous zirconium tetrachloride in ether or methyl tert-butyl ether to generate the target bridged metallocene compound, which can reduce the amount of n-hexane while ensuring the product yield.

[0006] On one hand, the present invention provides a method for preparing a bridged metallocene compound, comprising: (1) reacting fluorene and / or its derivatives with alkyl lithium in an organic solvent to obtain a reaction solution 1; (2) mixing the reaction solution 1 with fulvene and / or its derivatives to react to obtain a reaction solution 2; (3) mixing the reaction solution 2 with alkyl lithium to react, and obtaining a dilithium salt of a bridged metallocene compound ligand through solid-liquid separation; (4) mixing the dilithium salt of the bridged metallocene compound ligand with a tetrahalide of a Group IVB metal to react, and obtaining the bridged metallocene compound through post-treatment.

[0007] In the above-mentioned preparation method, the fluorene and / or its derivatives in step (1) are selected from at least one of the compounds represented by formula (I):

[0008]

[0009] In formula (I), R 5 , R 6 , R 7 , R 8 , R 9 , R 10 , R 11 or R 12 are each independently selected from hydrogen, C 1～20 Alkyl, C 1～20 Alkoxy, 1 to 3 C 1～20 Alkyl-substituted silicon, 1-2 C 1～20 Alkyl substituted amine, C 1～20 The alkenyl group, C 1～20 Alkynyl, C 6～20 Aryl or C 6～20 of alkylaryl.

[0010] In the above-mentioned preparation method, the alkyl lithiums in step (1) and step (3) are each independently selected from at least one of methyl lithium, diphenylmethyl lithium, triphenylmethyl lithium, ethyl lithium, n-propyl lithium, isopropyl lithium, n-butyl lithium, 3-(dimethylamino)propyl lithium, 2-butyl lithium, isobutyl lithium, tert-butyl lithium, pentyl lithium, hexyl lithium, phenyl lithium, 2,4,6-trimethylphenyl lithium, benzyl lithium, diisopropyl amide lithium, and bis(trimethylsilyl)amide lithium.

[0011] In the above-mentioned preparation method, the organic solvent in step (1) is selected from ether organic solvents.

[0012] In the above-mentioned preparation method, in step (1), the molar ratio of the fluorene and / or its derivative to the alkyl lithium is 1:(0.9-1.2), preferably 1:(0.9-1.05).

[0013] In the above-mentioned preparation method, the reaction conditions of step (1) include: temperature of -20 to 100°C and time of 1 to 24 hours.

[0014] In the above-mentioned preparation method, the fulvene and / or its derivative in step (2) is selected from at least one of the compounds represented by formula (II):

[0015]

[0016] In formula (II), R 1 , R 2 , R 3 , R 4 are each independently selected from hydrogen, C 1～20 Alkyl, C 1～20 Alkoxy, 1 to 3 C 1～20 Alkyl-substituted silicon, 1-2 C 1～20 Alkyl substituted amine, C 1～20 The alkenyl group, C 1～20 Alkynyl, C 6～20 Aryl or C 6～20 Alkyl aryl; R 13 Selected from hydrogen, C 1～20 Alkyl, C 6～20 Aryl or C 6～20 The alkylaryl group, two R 13 Same or different.

[0017] In the above-mentioned preparation method, the molar ratio of the fulvene and / or its derivatives in step (2) to the fluorene and / or its derivatives in step (1) is (0.9-2):1, preferably (1-1.05):1.

[0018] In the above-mentioned preparation method, in step (2), the reaction conditions include: temperature of -20 to 80°C and time of 4 to 48 hours.

[0019] In the above-mentioned preparation method, the molar ratio of the alkyl lithium in step (3) to the fluorene and / or its derivatives in step (1) is (0.9-1.2):1, preferably (1-1.05):1.

[0020] In the above-mentioned preparation method, in step (3), the reaction conditions include: temperature of -80 to 100°C and time of 1 to 24 hours.

[0021] In the above-mentioned preparation method, in step (4), the tetrahalide of the Group IVB metal is selected from one or more of MX4, wherein M is selected from titanium, zirconium or hafnium, and X is selected from fluorine, chlorine, bromine or iodine.

[0022] In step (4), the molar ratio of the tetrahalide of the Group IVB metal to the dilithium salt of the bridged metallocene compound ligand is (0.8-1.2):1, preferably (1-1.05):1; and / or,

[0023] In the above-mentioned preparation method, in step (4), the reaction conditions include: temperature of -80 to 60°C and time of 8 to 96 hours.

[0024] In the above-mentioned preparation method, in step (4), the post-treatment includes: a first solid-liquid separation to obtain a solid phase, dissolving the filter cake in an organic solvent, settling, a second solid-liquid separation to obtain a liquid phase, concentrating and then crystallizing the liquid phase, and drying the solid phase crystals to obtain the bridged metallocene compound.

[0025] The second aspect of the present invention is to provide a bridged metallocene compound obtained by the above preparation method. Preferably, the purity of the bridged metallocene compound is 96% to 100%.

[0026] The third aspect of the present invention is to provide the use of the bridged metallocene compound obtained by the above preparation method in olefin homopolymerization and olefin copolymerization, especially in the polymerization of syndiotactic polypropylene, polyolefin elastomer / plastomer, cycloolefin copolymer, polar monomer copolymer, and poly-α-olefin.

[0027] The endpoints and any values ​​of the scope disclosed in the present invention are not limited to the precise scope or value, and these scopes or values ​​should be understood to include values ​​close to these scopes or values. For numerical ranges, the endpoint values ​​of each scope, the endpoint values ​​of each scope and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be regarded as specifically disclosed in this article. Hereinafter, in principle, each technical solution can be combined with each other to obtain a new technical solution, which should also be regarded as specifically disclosed in this article.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] (1) The synthesis method proposed in the present invention has the advantages of using less alkyl lithium, preventing waste of zirconium tetrachloride, reducing the content of by-products, improving the yield of bridged metallocene compounds and preventing the product from being too dark in color, having less residual solvent in the final product, and reducing the amount of organic solvent used for washing; it is conducive to the industrial production of the catalyst;

[0030] (2) The intermediate product, the dilithium salt of the bridged metallocene compound ligand, has a higher yield, and the final product, the bridged metallocene compound, also has a higher yield and higher purity. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 The NMR spectrum of the product obtained in Example 1 is shown;

[0032] Figure 2 The NMR spectrum of the product obtained in Comparative Example 1 is shown. DETAILED DESCRIPTION

[0033] The following detailed description of the present invention will make the features and advantages of the present invention more clear and explicit.

[0034] One of the purposes of the present invention is to provide a method for preparing a bridged metallocene compound, comprising: (1) reacting fluorene and / or its derivatives with alkyl lithium in an organic solvent to obtain a reaction solution 1; (2) mixing the reaction solution 1 with fulvene and / or its derivatives to react to obtain a reaction solution 2; (3) mixing the reaction solution 2 with alkyl lithium to react, and obtaining a dilithium salt of a bridged metallocene compound ligand through solid-liquid separation; (4) mixing the dilithium salt of the bridged metallocene compound ligand with a tetrahalide of a Group IVB metal to react, and obtaining the bridged metallocene compound through post-treatment.

[0035] In a preferred embodiment, the fluorene and / or its derivatives in step (1) are selected from at least one of the compounds represented by formula (I):

[0036]

[0037] In formula (I), R 5 , R 6 , R 7 , R 8 , R 9 , R 10 , R 11 or R 12 are each independently selected from hydrogen, C 1～20 Alkyl, C 1～20 Alkoxy, 1 to 3 C 1～20 Alkyl-substituted silicon, 1-2 C 1～20 Alkyl substituted amine, C 1～20 The alkenyl group, C 1～20 Alkynyl, C 6～20 Aryl or C 6～20 of alkylaryl.

[0038] In a further preferred embodiment, in formula (I), R 5 , R 6 , R 7 , R 8 , R 9 , R 10 , R 11 or R 12 are each independently selected from hydrogen, C1～10 Alkyl, C 1～10 Alkoxy, C 1～20 Alkyl-substituted silicon, C 1～20 Alkyl substituted amine, C 1～10 The alkenyl group, C 1～10 Alkynyl, C 6～10 Aryl or C 6～10 of alkylaryl.

[0039] In a preferred embodiment, the alkyl lithiums in step (1) and step (3) are each independently selected from at least one of methyl lithium, diphenylmethyl lithium, triphenylmethyl lithium, ethyl lithium, n-propyl lithium, isopropyl lithium, n-butyl lithium, 3-(dimethylamino)propyl lithium, 2-butyl lithium, isobutyl lithium, tert-butyl lithium, pentyl lithium, hexyl lithium, phenyl lithium, 2,4,6-trimethylphenyl lithium, benzyl lithium, diisopropyl amide lithium, and bis(trimethylsilyl)amide lithium; preferably, the alkyl lithium used is n-butyl lithium.

[0040] In a further preferred embodiment, the organic solvent in step (1) is selected from ether organic solvents, preferably butyl ether.

[0041] Among them, after a large number of experimental studies, the inventors found that compared with other organic solvents (such as tetrahydrofuran), the dilithium salt of the bridged metallocene compound ligand obtained by using an ether organic solvent (preferably butyl ether) as a solvent in step (1) has a higher yield, and the toxicity of butyl ether is lower than that of tetrahydrofuran.

[0042] In a preferred embodiment, in step (1), the molar ratio of the fluorene and / or its derivative to the alkyl lithium is 1:(0.9-1.2), preferably 1:(0.9-1.05), for example 1:0.9, 1:1, 1:1.1 or 1:1.2.

[0043] In a preferred embodiment, the reaction conditions of step (1) include: temperature of -20 to 100°C and time of 1 to 24 hours.

[0044] For example, the reaction conditions of step (1) include: temperature of -20°C, -10°C, 0°C, 10°C, 20°C, 30°C, 40°C, 50°C, 60°C, 70°C, 80°C, 90°C or 100°C, and time of 1h, 2h, 5h, 8h, 10h, 12h, 15h, 18h, 20h, 22h or 24h.

[0045] In a further preferred embodiment, the reaction conditions of step (1) include: temperature of 20 to 40° C. and time of 4 to 8 h.

[0046] In a preferred embodiment, step (1) comprises: (1.1) mixing fluorene and / or its derivatives with an ether solvent (preferably butyl ether) to obtain a solution of fluorene and / or its derivatives (preferably butyl ether solution); (2) adding a solution of alkyl lithium dropwise to the solution of fluorene and / or its derivatives (preferably butyl ether solution) to carry out a reaction.

[0047] In a preferred embodiment, the fulvene and / or its derivative in step (2) is selected from at least one of the compounds represented by formula (II):

[0048]

[0049] In formula (II), R 1 , R 2 , R 3 , R 4 are each independently selected from hydrogen, C 1～20 Alkyl, C 1～20 Alkoxy, 1 to 3 C 1～20 Alkyl-substituted silicon, 1-2 C 1～20 Alkyl substituted amine, C 1～20 The alkenyl group, C 1～20 Alkynyl, C 6～20 Aryl or C 6～20 Alkyl aryl; R 13 Selected from hydrogen, C 1～20 Alkyl, C 6～20 Aryl or C 6～20 The alkylaryl group, two R 13 Same or different.

[0050] In a further preferred embodiment, in formula (II), R 1 , R 2 , R 3 , R 4 are each independently selected from hydrogen, C 1～10 Alkyl, C 1～10 Alkoxy, 1 to 3 C 1～10 Alkyl-substituted silicon, 1-2 C 1～10 Alkyl substituted amine, C 1～10 The alkenyl group, C 1～10 Alkynyl, C 6～10 Aryl or C 6～10 Alkyl aryl; R 13 Selected from hydrogen, C 1～10 Alkyl, C 6～10 Aryl or C 6～10 The alkylaryl group, two R 13 Same or different.

[0051] In a preferred embodiment, the molar ratio of the fulvene and / or its derivatives in step (2) to the fluorene and / or its derivatives in step (1) is (0.9-2):1, preferably (1-1.05):1, for example, 0.9:1, 1:1, 1.2:1, 1.4:1, 1.6:1, 1.8:1 or 2:1.

[0052] In a preferred embodiment, in step (2), the reaction conditions include: temperature of -20 to 80°C and time of 4 to 48 hours.

[0053] For example, in step (2), the reaction conditions include: temperature of -20°C, -10°C, 0°C, 10°C, 20°C, 30°C, 40°C, 50°C, 60°C, 70°C or 80°C, and time of 4h, 5h, 10h, 15h, 20h, 25h, 30h, 35h, 40h, 45h or 48h.

[0054] In a further preferred embodiment, in step (2), the reaction conditions include: temperature of 20 to 50° C., and time of 8 to 16 hours.

[0055] In a preferred embodiment, step (2) comprises: dissolving the fulvene and / or its derivatives in the organic solvent (preferably an ether solvent, such as dibutyl ether) to obtain a solution of the fulvene and / or its derivatives; adding the solution of the fulvene and / or its derivatives to the reaction solution 1 to react.

[0056] In a further preferred embodiment, before adding the fulvene and / or its derivatives to the reaction solution one, the temperature of the reaction solution one is first reduced to 5-25°C, for example, to 5°C, 10°C, 15°C, 20°C or 25°C.

[0057] In a preferred embodiment, the molar ratio of the alkyl lithium in step (3) to the fluorene and / or its derivatives in step (1) is (0.9-1.2):1, preferably (1-1.05):1, for example, 0.9:1, 1:1, 1.1:1 or 1.2:1.

[0058] In a preferred embodiment, in step (3), the reaction conditions include: temperature of -80 to 100°C and time of 1 to 24 hours.

[0059] For example, in step (3), the reaction conditions include: temperature of -80°C, -70°C, -60°C, -50°C, -40°C, -30°C, -20°C, -10°C, 0°C, 10°C, 20°C, 30°C, 40°C, 50°C, 60°C, 70°C, 80°C, 90°C or 100°C, and time of 1 h, 4 h, 5 h, 10 h, 15 h, 20 h or 24 h.

[0060] In a further preferred embodiment, in step (3), the reaction conditions include: temperature of 20 to 40° C., and time of 8 to 16 hours.

[0061] In a preferred embodiment, in step (3), before adding the alkyl lithium to the reaction solution 2, the reaction solution 2 is first cooled to 5-25°C, for example, 5°C, 10°C, 15°C, 20°C or 25°C.

[0062] In a preferred embodiment, the solid-liquid separation in step (3) is filtration or centrifugation, preferably filtration.

[0063] Among them, the inventors found that in the butyl ether system of the present invention, the dilithium salt of the bridged metallocene compound ligand exists in the solid phase, while the by-product is dissolved in the liquid phase. Therefore, the purpose of removing the by-product can be cleverly achieved through solid-liquid separation, and the dilithium salt of the bridged metallocene compound ligand can be separated out with high yield.

[0064] In a preferred embodiment, an organic solvent is used for washing after the solid-liquid separation in step (3), and the organic solvent is selected from at least one of an alkane solvent and an ether solvent.

[0065] In a preferred embodiment, in step (4), the tetrahalide of Group IVB metal is selected from one or more of MX4, wherein M is selected from titanium, zirconium or hafnium, and X is selected from fluorine, chlorine, bromine or iodine.

[0066] In a preferred embodiment, in step (4), the molar ratio of the tetrahalide of the Group IVB metal to the dilithium salt of the bridged metallocene compound ligand is (0.8-1.2):1, preferably (1-1.05):1, for example, 0.8:1, 0.9:1, 1:1, 1.1:1 or 1.2:1.

[0067] In a preferred embodiment, step (4) comprises: (4.1) mixing the tetrahalide of the Group IVB metal with dispersant 1 to obtain dispersion 1, and mixing the dilithium salt of the bridged metallocene compound ligand with dispersant 2 to obtain dispersion 2; (4.2) mixing the dispersion 1 and the dispersion 2 to react.

[0068] In the present invention, the tetrahalide of the IVB group metal and the dilithium salt of the bridged metallocene compound ligand are prepared as independent solutions and then mixed. The reason is that: after a large number of experimental studies, the inventors found that if the tetrahalide of the IVB group metal is directly added to the solution of the dilithium salt of the bridged metallocene compound ligand, the tetrahalide of the IVB group metal will release heat violently, resulting in an increase in by-products (because it reacts while releasing heat). However, the present invention first prepares the dispersion of the tetrahalide of the IVB group metal, and heat is released during the preparation process. Therefore, when it is mixed with the dilithium salt of the bridged metallocene compound ligand, the problem of increasing by-products due to heat release and reaction occurs.

[0069] In a further preferred embodiment, the dispersion one is obtained at below 20°C (preferably -30°C to 20°C, for example -30°C, -20°C, -10°C, 0°C, 10°C or 20°C), and / or the dispersion two is added dropwise into the solution one for the mixing.

[0070] In a further preferred embodiment, the dispersant 1 and the dispersant 2 are each independently selected from one or more of diethyl ether, propyl ether, isopropyl ether, methyl propyl ether, methyl tert-butyl ether, methyl n-butyl ether, and ethyl propyl ether.

[0071] Among them, the inventors found after a lot of experimental studies that the heat release of the tetrahalide of the Group IVB metal in the above-mentioned dispersion solvent is significantly lower than that in tetrahydrofuran, and therefore the above-mentioned dispersion solvent is preferred.

[0072] In a further preferred embodiment, the weight concentration of the tetrahalide of Group IVB metal in the dispersion 1 is 2-15wt%, preferably 6-9wt%, for example 2wt%, 4wt%, 6wt%, 8wt%, 10wt%, 12wt%, 14wt% or 15wt%.

[0073] In a preferred embodiment, in step (4), the reaction conditions include: temperature of -80 to 60°C and time of 8 to 96 hours.

[0074] For example, in step (4), the reaction conditions include: temperature of -80°C, -60°C, -40°C, -20°C, 0°C, 20°C, 40°C or 60°C, and time of 8h, 10h, 15h, 20h, 25h, 30h, 35h, 40h, 45h, 50h, 55h, 60h, 65h, 70h, 75h, 80h, 85h, 90h, 95h or 96h.

[0075] In a further preferred embodiment, in step (4), the reaction conditions include: temperature of 30-40° C. and time of 24-48 h.

[0076] In a preferred embodiment, in step (4), the post-treatment includes: a first solid-liquid separation (such as filtration) to obtain a solid phase, dissolving the filter cake in an organic solvent, settling, a second solid-liquid separation (such as filtration or centrifugation) to obtain a liquid phase, concentrating the liquid phase and then obtaining solid phase crystals (preferably by filtration or decanting) and drying to obtain the bridged metallocene compound.

[0077] In a further preferred embodiment, the organic solvent is selected from one or more of halogenated alkanes, benzene, toluene, xylene, ethyl acetate, acetone, and acetonitrile, preferably from halogenated alkanes, such as one or more of dichloromethane, chloroform, 1,2-dichloroethane, and 1,1-dichloroethane.

[0078] Among them, the solvent system in steps (1) to (3) of the present invention is preferably butyl ether. If no post-treatment is performed, the product will contain residual butyl ether. Therefore, post-treatment is required to remove the residual butyl ether by re-dissolving the filter cake in the above organic solvent. In addition, the method will produce lithium chloride as a by-product. The lithium chloride by-product is a very fine solid phase. It is difficult to remove it if it is only a simple solid-liquid separation. Therefore, after the filter cake is obtained by the first solid-liquid separation, the filter cake is dissolved in the above organic solvent (preferably a halogenated alkane). It is found that the product can be dissolved in the liquid phase while the lithium chloride still exists in the solid phase. Therefore, the lithium chloride can be removed by solid-liquid separation again.

[0079] In a further preferred embodiment, the second solid-liquid separation in the post-treatment is preferably centrifugal separation.

[0080] Among them, the inventors found in a large number of experiments that since the particles of lithium chloride are very fine, if filtering is used, the filter membrane may be clogged, so centrifugal separation is preferably used.

[0081] The reaction process of the method of the present invention is shown in the following formula:

[0082]

[0083] The method of the invention has the effects of no butyl ether residue, reduced by-product content and increased yield of bridged metallocene compounds.

[0084] The second object of the present invention is to provide a bridged metallocene compound obtained by the preparation method described in the first object of the present invention.

[0085] In a preferred embodiment, the purity of the bridged metallocene compound is 96% to 100%, preferably 98% to 100%, for example 96%, 97%, 98%, 99% or 100%.

[0086] The third object of the present invention is to provide the use of the bridged metallocene compound obtained by the preparation method described in one of the objects of the present invention in olefin polymerization, especially in the polymerization of syndiotactic polypropylene, polyolefin elastomer / plastomer, cycloolefin copolymer, polar monomer copolymer, and poly-α-olefin.

[0087] Example

[0088] The present invention is described in detail below in conjunction with specific embodiments. It is necessary to point out that the following embodiments are only used to further illustrate the present invention and cannot be understood as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made to the present invention by those skilled in the art based on the contents of the present invention still fall within the scope of protection of the present invention.

[0089] It should also be noted that the various specific technical features described in the following specific embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0090] In addition, the various embodiments of the present invention may be arbitrarily combined as long as they do not violate the concept of the present invention. The technical solutions thus formed belong to part of the original disclosure of this specification and also fall within the protection scope of the present invention.

[0091] The raw materials used in the examples and comparative examples, unless otherwise specified, are disclosed in the prior art, for example, they can be directly purchased or prepared according to the preparation methods disclosed in the prior art.

[0092] [Example 1] Preparation of diphenylmethylene (cyclopentadienyl) (9-fluorenyl) zirconium dichloride I-1

[0093]

[0094] Under nitrogen protection, 195g of fluorene (1.17mol) was dissolved in 3.7L of butyl ether, and 492mL (1.23mol, 1.05equiv) of 2.5mol / L n-butyl lithium in n-hexane solution was slowly added dropwise at 15°C, the temperature was raised to 30°C, and stirred for 6h. The reaction system was cooled to 15°C, 283g of dibenzofulvene (1.23mol, 1.05equiv) dissolved in 2.8L of butyl ether was added, the temperature was raised to 30°C, and stirred for 12h. The temperature was lowered to 15°C, 492mL (1.23mol, 1.05equiv) of 2.5mol / L n-butyl lithium in n-hexane solution was slowly added dropwise, the temperature was raised to 30°C, and stirred for 12h. The mixture was filtered under nitrogen protection, and the filter cake was washed with 300 mL of n-hexane to obtain 408 g of orange-yellow solid [diphenylmethylene (cyclopentadienyl) (9-fluorenyl) dilithium salt] with a yield of 85%.

[0095] Cool 4L of ether to -25°C, add 235g (1.01mol) of zirconium tetrachloride in batches, stir evenly, and then dropwise add a suspension of 408g (1.00mol) of diphenylmethylene (cyclopentadienyl) (9-fluorenyl) dilithium salt obtained in step (1) mixed in 1L of ether, add 1L of ether for washing, heat to 30°C, and stir for 36h. After the reaction is complete, filter, transfer the filter cake to a drying kettle, and dry under reduced pressure to obtain a crude product containing lithium chloride. Dissolve the crude product in 25L of 1,2-dichloroethane at 50°C, cool, centrifuge, combine the supernatants, concentrate under reduced pressure to about 1L, decant, filter, and dry under reduced pressure to obtain 498g of a red solid with a yield of 90% and a purity of 98% ( 1 HNMR internal standard reference, the internal standard is dibromomethane). 1 The H NMR data are as follows, and the spectrum is as follows Figure 1 shown.

[0096] 1 H NMR (400MHz, CDCl3) δ8.20(d,J=8.4Hz,2H),7.94(d,J=8.0Hz,2H),7.87(d,J=7.8Hz,2H),7.62-7.54(m,2H),7.44(td,J=7.5,1.6 Hz,2H),7.38-7.26(m,4H),7.02(ddd,J=8.8,6.9,1.2Hz,2H),6.43(d,J=8.9Hz,2H),6.39(t,J=2.7Hz,2H),5.81(t,J=2.7Hz,2H).

[0097] [Example 2] Preparation of dimethylmethylene (cyclopentadienyl) (9-fluorenyl) zirconium dichloride I-2

[0098]

[0099] Under nitrogen protection, 195g of fluorene (1.17mol) was dissolved in 3.7L of butyl ether, and 492mL (1.23mol, 1.05equiv) of 2.5mol / L n-butyl lithium in n-hexane solution was slowly added dropwise at 15°C, the temperature was raised to 30°C, and stirred for 6h. The reaction system was cooled to 15°C, 130g of dimethylfulvene (1.23mol, 1.05equiv) solution dissolved in 2.8L of butyl ether was added, the temperature was raised to 30°C, and stirred for 12h. The temperature was lowered to 15°C, 492mL (1.23mol, 1.05equiv) of 2.5mol / L n-butyl lithium in n-hexane solution was slowly added dropwise, the temperature was raised to 30°C, and stirred for 12h. The mixture was filtered under nitrogen protection, and the filter cake was washed with 300 mL of n-hexane. The process was repeated three times to obtain 273 g of a yellow solid [dimethylmethylene (cyclopentadienyl) (9-fluorenyl) dilithium salt] with a yield of 82%.

[0100] Cool 4L of ether to -25°C, add 226g (0.97mol) of zirconium tetrachloride in batches, stir evenly, and then dropwise add a suspension of 273g (0.96mol) of dimethylmethylene (cyclopentadienyl) (9-fluorenyl) dilithium salt obtained in step (1) mixed in 1L of ether, add 1L of ether for washing, slowly raise the temperature to 30°C, and stir for 36h. After the reaction is complete, filter, transfer the filter cake to a drying kettle, and dry under reduced pressure to obtain a crude product containing lithium chloride. Dissolve the crude product in 25L of 1,2-dichloroethane at 50°C, cool, centrifuge, combine the supernatants, concentrate under reduced pressure to about 1L, decant, filter, and dry under reduced pressure to obtain 368g of a red solid with a yield of 89% and a purity of 98% ( 1 HNMR internal standard reference, the internal standard is dibromomethane).

[0101] 1 The H NMR data are as follows: 1 H NMR (400MHz, CDCl3) δ7.61(d,J=7.6Hz,2H),7.30(t,J=7.6Hz,2H),7.12(t,J=7.6Hz,2H),6.92(d,J=7.6Hz,2H),6.28-6.25(m,4H),1.43(s,6H).

[0102] [Example 3] Preparation of diphenylmethylene (cyclopentadienyl) (9-(2,7-di-tert-butyl) fluorenyl) zirconium dichloride I-3

[0103]

[0104] Under nitrogen protection, 326g 2,7-di-tert-butylfluorene (1.17mol) was dissolved in 3.7L butyl ether, and 492mL (1.23mol, 1.05equiv) of 2.5mol / L n-butyl lithium in n-hexane solution was slowly added dropwise at 15°C, the temperature was raised to 30°C, and stirred for 6h. The reaction system was cooled to 15°C, 283g dibenzofulvene (1.23mol, 1.05equiv) solution dissolved in 2.8L butyl ether was added, the temperature was raised to 30°C, and stirred for 12h. The temperature was lowered to 15°C, 492mL (1.23mol, 1.05equiv) of 2.5mol / L n-butyl lithium in n-hexane solution was slowly added dropwise, the temperature was raised to 30°C, and stirred for 12h. The mixture was filtered under nitrogen protection, and the filter cake was washed with 300 mL of n-hexane. The process was repeated three times to obtain 458 g of an orange-yellow solid [diphenylmethylene (cyclopentadienyl) (9-(2,7-di-tert-butyl)fluorenyl) dilithium salt] with a yield of 76%.

[0105] Cool 4L of ether to -25°C, add 288g (0.89mol) of zirconium tetrachloride in batches, stir evenly, and then dropwise add a suspension of 458g (0.88mol) of diphenylmethylene (cyclopentadienyl) (9-(2,7-di-tert-butyl)fluorenyl) dilithium salt obtained in step (1) mixed with 1L of ether, add 1L of ether to rinse the reactor, heat to 30°C, and stir for 36h. After the reaction is complete, filter, transfer the filter cake to a drying kettle, and dry under reduced pressure to obtain a crude product containing lithium chloride. Dissolve the crude product in 25L of 1,2-dichloroethane at 50°C, cool, centrifuge, combine the supernatants, concentrate under reduced pressure to about 1L, decant, filter, and dry under reduced pressure to obtain 477g of a red solid with a yield of 81% and a purity of 96% ( 1 HNMR internal standard reference, the internal standard is dibromomethane).

[0106] 1 The H NMR data are as follows: 1 H NMR (400MHz, CDCl3) δ8.06(d,J=8.8Hz,2H),7.96(dt,J=8.0,1.5Hz,2H),7.89(dt,J=7.8,1.5Hz,2H),7.61(dd,J=8.8,1.6Hz,2H),7.46(td,J=7.6,1. 6Hz,2H),7.36(td,J=7.6,1.6Hz,2H),7.30(dt,J=7.4,1.2Hz,2H),6.36(t ,J=2.7Hz,2H),6.33(d,J=0.9Hz,2H),5.68(t,J=2.7Hz,2H),1.03(s,18H).

[0107] [Example 4] Preparation of diphenylmethylene (cyclopentadienyl) (9-fluorenyl) hafnium dichloride I-4

[0108]

[0109] Under nitrogen protection, 195g of fluorene (1.17mol) was dissolved in 3.7L of butyl ether, and 492mL (1.23mol, 1.05equiv) of 2.5mol / L n-butyl lithium in n-hexane solution was slowly added dropwise at 15°C, the temperature was raised to 30°C, and stirred for 6h. The reaction system was cooled to 15°C, 283g of dibenzofulvene (1.23mol, 1.05equiv) dissolved in 2.8L of butyl ether was added, the temperature was raised to 30°C, and stirred for 12h. The temperature was lowered to 15°C, 492mL (1.23mol, 1.05equiv) of 2.5mol / L n-butyl lithium in n-hexane solution was slowly added dropwise, the temperature was raised to 30°C, and stirred for 12h. The mixture was filtered under nitrogen protection, and the filter cake was washed with 300 mL of n-hexane. The process was repeated three times to obtain 408 g of an orange-yellow solid [diphenylmethylene (cyclopentadienyl) (9-fluorenyl) dilithium salt] with a yield of 85%.

[0110] Cool 4L of ether to -25°C, add 323g (1.01mol) of hafnium tetrachloride in batches, stir evenly, and then dropwise add a suspension of 408g (1.00mol) of diphenylmethylene (cyclopentadienyl) (9-fluorenyl) dilithium salt obtained in step (1) mixed in 1L of ether, add 1L of ether for washing, heat to 30°C, and stir for 36h. After the reaction is complete, filter, transfer the filter cake to a drying kettle, and dry under reduced pressure to obtain a crude product containing lithium chloride. Dissolve the crude product in 25L of 1,2-dichloroethane at 50°C, cool, centrifuge, combine the supernatants, concentrate under reduced pressure to about 1L, decant, filter, and dry under reduced pressure to obtain 487g of a red solid with a yield of 76% and a purity of 96% ( 1 HNMR internal standard reference, the internal standard is dibromomethane).

[0111] 1 The H NMR data are as follows: 1 H NMR (400MHz, CDCl3) δ8.18(d,J=8.4Hz,2H),7.94(d,J=7.9Hz,2H),7.87(d,J=7.8Hz,2H),7.55(ddd,J=8.4,6.8,0.9Hz,2H),7.44(td,J=7 .4,1.5Hz,2H),7.37-7.28(m,4H),6.99(ddd,J=8.8,6.8,1.2Hz,2H),6.46(d,J=8.8Hz,2H),6.33(t,J=2.7Hz,2H),5.75(t,J=2.7Hz,2H).

[0112] [Comparative Example 1] Preparation of diphenylmethylene (cyclopentadienyl) (9-fluorenyl) zirconium dichloride I-1

[0113] Under nitrogen protection, 195g of fluorene (1.17mol) was dissolved in 3.7L of ether, and 492mL (1.23mol, 1.05equiv) of 2.5mol / L n-butyllithium in n-hexane solution was slowly added dropwise at 15°C, and the temperature was raised to 30°C, and stirred for 6h. The reaction system was cooled to 15°C, and a solution of 283g of dibenzofulvene (1.23mol, 1.05equiv) dissolved in 2.8L of ether was added, and the temperature was raised to 30°C, and stirred for 12h. 1L of distilled water was added, and the mixture was stirred for 30min, and the liquid was separated, and the organic phase was collected and dried to obtain 372g of orange-yellow solid with a yield of 80%.

[0114] Under nitrogen protection, 372g of the orange-yellow solid obtained in step 1 was dissolved in 8L of ether, cooled to 15°C, 926mL (2.32mol, 2.10equiv) of 2.5mol / L n-butyllithium in n-hexane solution was slowly added dropwise, the temperature was raised to 30°C, and stirred for 12h. Cooled to -25°C, 222g (0.953mol) of zirconium tetrachloride was added in batches, the temperature was slowly raised to 30°C, and stirred for 36h. After the reaction was complete, the filter cake was washed three times with 300mL of n-hexane to obtain a crude product containing lithium chloride. The crude product was dissolved in 25L of 1,2-dichloroethane at 50°C, cooled, centrifuged, the supernatant was combined, concentrated to about 1L under reduced pressure, and decanted. Add 500mL of 1,2-dichloroethane, stir evenly, settle, decanted, and repeated 4 times until the 1,2-dichloroethane solution turned red. After drying under reduced pressure, 395 g of red solid was obtained with a yield of 76% and a purity of 90% ( 1 HNMR internal standard reference, the internal standard is dibromomethane). 1 H NMR spectrum Figure 2 shown.

[0115] Compared with Comparative Example 1, the bridged metallocene compound obtained in Example 1 has a higher yield, a lighter color, and fewer impurity peaks in the low-field part of the NMR spectrum.

[0116] [Comparative Example 2]

[0117] Under nitrogen protection, 195g of fluorene (1.17mol) was dissolved in 3.7L of tetrahydrofuran, and 492mL (1.23mol, 1.05equiv) of 2.5mol / L n-butyllithium in n-hexane solution was slowly added dropwise at 15°C, the temperature was raised to 30°C, and stirred for 6h. The reaction system was cooled to 15°C, 283g of dibenzofulvene (1.23mol, 1.05equiv) solution dissolved in 2.8L of tetrahydrofuran was added, the temperature was raised to 30°C, and stirred for 12h. The temperature was lowered to 15°C, 492mL (1.23mol, 1.05equiv) of 2.5mol / L n-butyllithium in n-hexane solution was slowly added dropwise, the temperature was raised to 30°C, and stirred for 12h. The mixture was filtered under nitrogen protection, and the filter cake was washed with 300 mL of n-hexane to obtain 375 g of orange-yellow solid [diphenylmethylene (cyclopentadienyl) (9-fluorenyl) dilithium salt] with a yield of 78%.

[0118] Cool 4L of ether to -25°C, add 216g (0.928mol) of zirconium tetrachloride in batches, stir evenly, dropwise add 375g (0.919mol) of diphenylmethylene (cyclopentadienyl) (9-fluorenyl) dilithium salt obtained in step (1) in 1L of ether suspension, add 1L of ether for washing, heat to 30°C, and stir for 36h. After the reaction is complete, filter, transfer the filter cake to a drying kettle, and dry under reduced pressure to obtain a crude product containing lithium chloride. Dissolve the crude product in 25L of 1,2-dichloroethane at 50°C, cool, centrifuge, combine the supernatants, concentrate under reduced pressure to about 1L, decant, filter, and dry under reduced pressure to obtain 445g of red solid, with a yield of 87% and a purity of 96%.

[0119] [Comparative Example 3]

[0120] The process of Example 1 was repeated, except that no post-treatment was performed in step (2), that is, the filter cake obtained by filtration after the reaction was complete was the product. The yield was 109% and the purity was 85%.

[0121] [Example 5] Polymerization Evaluation of Bridged Metallocene Compounds

[0122] In a 1L pressure reactor under 1 bar ethylene atmosphere at 25°C, 500 mL of n-hexane and 6 μmol of [(C6H5)3C] + [(C6F5)4B] - , 2mL of 1mol / L triisobutylaluminum toluene solution and a certain amount of comonomer. Add 5μmol of metallocene main catalyst, increase the ethylene pressure to 4bar, react at 110℃ for 10min, stop feeding ethylene, and obtain ethylene copolymer. The polymerization evaluation results of some bridged metallocene compounds, including reaction activity, product density and melt index, are shown in Table 1.

[0123] Table 1 Polymerization evaluation of bridged metallocene compounds

[0124]

[0125]

[0126] The catalyst of Comparative* is dimethylsilylbis(2-methylindenyl)zirconium dichloride.

[0127] It can be seen from Table 1 that the bridged metallocene compound of the present invention can be used for olefin polymerization and has high reactivity.

[0128] The present invention has been described in detail above in conjunction with specific implementations and exemplary examples, but these descriptions cannot be understood as limiting the present invention. Those skilled in the art understand that, without departing from the spirit and scope of the present invention, a variety of equivalent substitutions, modifications or improvements may be made to the technical solution of the present invention and its implementation methods, all of which fall within the scope of the present invention. The scope of protection of the present invention shall be subject to the attached claims.

Claims

1. A method for preparing a bridged metallocene compound, comprising: (1) reacting fluorene and / or its derivatives with alkyl lithium in an organic solvent to obtain a reaction solution 1; (2) mixing the reaction solution 1 with fulvene and / or its derivatives to react to obtain a reaction solution 2; (3) mixing the reaction solution 2 with alkyl lithium to react to obtain a dilithium salt of a bridged metallocene compound ligand through solid-liquid separation; (4) mixing the dilithium salt of the bridged metallocene compound ligand with a tetrahalide of a Group IVB metal to react, and then performing post-treatment to obtain the bridged metallocene compound.

2. The preparation method according to claim 1, characterized in that: In step (1), the fluorene and / or its derivatives are selected from at least one of the compounds represented by formula (I): In formula (I), R 5 , R 6 , R 7 , R 8 , R 9 , R 10 , R 11 or R 12 are each independently selected from hydrogen, C 1～20 Alkyl, C 1～20 Alkoxy, 1 to 3 C 1～20 Alkyl-substituted silicon, 1-2 C 1～20 Alkyl substituted amine, C 1～20 The alkenyl group, C 1～20 Alkynyl, C 6～20 Aryl or C 6～20 of alkylaryl.

3. The preparation method according to claim 1, characterized in that: The alkyl lithium in step (1) and step (3) is independently selected from at least one of methyl lithium, diphenylmethyl lithium, triphenylmethyl lithium, ethyl lithium, n-propyl lithium, isopropyl lithium, n-butyl lithium, 3-(dimethylamino)propyl lithium, 2-butyl lithium, isobutyl lithium, tert-butyl lithium, pentyl lithium, hexyl lithium, phenyl lithium, 2,4,6-trimethylphenyl lithium, benzyl lithium, diisopropyl amide lithium, and bis(trimethylsilyl)amide lithium; and / or, The organic solvent in step (1) is selected from ether organic solvents.

4. The preparation method according to claim 1, characterized in that: In step (1), the molar ratio of the fluorene and / or its derivative to the alkyl lithium is 1:(0.9-1.2), preferably 1:(0.9-1.05); and / or, The reaction conditions of step (1) include: temperature of -20 to 100° C. and time of 1 to 24 h.

5. The preparation method according to claim 1, characterized in that: The fulvene and / or its derivatives in step (2) are selected from at least one of the compounds represented by formula (II): In formula (II), R 1 , R 2 , R 3 , R 4 are each independently selected from hydrogen, C 1～20 Alkyl, C 1～20 Alkoxy, 1 to 3 C 1～20 Alkyl-substituted silicon, 1-2 C 1～20 Alkyl substituted amine, C 1～20 The alkenyl group, C 1～20 Alkynyl, C 6～20 Aryl or C 6～20 Alkyl aryl; R 13 Selected from hydrogen, C 1～20 Alkyl, C 6～20 Aryl or C 6～20 The alkylaryl group, two R 13 Same or different.

6. The preparation method according to claim 1, characterized in that: The molar ratio of the fulvene and / or its derivatives in step (2) to the fluorene and / or its derivatives in step (1) is (0.9-2):1, preferably (1-1.05):1; and / or, In step (2), the reaction conditions include: temperature of -20 to 80°C and time of 4 to 48 hours.

7. The preparation method according to claim 1, characterized in that: The molar ratio of the alkyl lithium in step (3) to the fluorene and / or its derivative in step (1) is (0.9-1.2):1, preferably (1-1.05):1; and / or, In step (3), the reaction conditions include: temperature of -80 to 100°C and time of 1 to 24 hours.

8. The preparation method according to claim 1, characterized in that: In step (4), the tetrahalide of Group IVB metal is selected from one or more of MX4, wherein M is selected from titanium, zirconium or hafnium, and X is selected from fluorine, chlorine, bromine or iodine; and / or, In step (4), the molar ratio of the tetrahalide of the Group IVB metal to the dilithium salt of the bridged metallocene compound ligand is (0.8-1.2):1, preferably (1-1.05):1; and / or, In step (4), the reaction conditions include: temperature of -80 to 60°C and time of 8 to 96 hours.

9. The preparation method according to any one of claims 1 to 8, characterized in that: In step (4), the post-treatment includes: a first solid-liquid separation to obtain a solid phase, dissolving the filter cake in an organic solvent, settling, a second solid-liquid separation to obtain a liquid phase, concentrating and then crystallizing the liquid phase, and drying the solid phase crystals to obtain the bridged metallocene compound.

10. The bridged metallocene compound obtained by the preparation method according to any one of claims 1 to 9, wherein the purity of the bridged metallocene compound is 96% to 100%.

11. Use of the bridged metallocene compound obtained by the preparation method according to any one of claims 1 to 9 in olefin homopolymerization and olefin copolymerization, especially in syndiotactic polypropylene, polyolefin elastomer / plastomer, cycloolefin copolymer, polar monomer copolymer, and poly-α-olefin polymerization.

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