A MgCl2-supported titanium-based catalyst, its preparation method and application

Abstract

This invention relates to a MgCl2 supported titanium catalyst, its preparation method, and its application. The preparation method includes: (1) preparing a MgCl2 support in situ by reacting a Grignard reagent containing a magnesium source with a chloride; (2) reacting the support with an organoaluminum compound to obtain an active MgCl2 support; and (3) mixing and loading the active support with an FI catalyst, washing and drying to obtain the target supported catalyst. Compared with the prior art, this invention can control the composition and morphology of the MgCl2 support by improving the types of Grignard reagent and chloride, which is beneficial to improving the activity of the FI catalyst. In addition, the preparation route of this invention is simple, and the obtained catalyst can be used to prepare ultra-high molecular weight polyethylene resin with a narrow molecular weight distribution, providing a new preparation method for supported FI catalysts.

Description

Technical Field

[0001] This invention belongs to the field of olefin polymerization technology, and relates to a MgCl2 supported titanium catalyst, its preparation method and application. Background Technology

[0002] Ultra-high molecular weight polyethylene (UHMWPE) is a homopolymer of ethylene with a molecular weight of over 1 million, and it is one of the hardest plastics known to date. Its ultra-high molecular weight endows UHMWPE with unique physicochemical properties, such as abrasion resistance, high impact resistance, lubricity, and chemical corrosion resistance, making it crucial in fields such as national defense, marine engineering, ropes and textiles, and sporting goods. The catalysts used in the preparation of UHMWPE are the core factor affecting its performance and have been a focus of research both domestically and internationally in recent years.

[0003] Based on their composition, catalysts for preparing UHMWPE can be classified into the following categories: Ziegler-Natta (ZN) catalysts, metallocene catalysts, and non-metallocene catalysts. Compared with the first two types of catalysts, non-metallocene catalysts have superior catalytic activity, enabling precise control of various performance parameters. Their main catalysts are relatively easier to synthesize, exhibit more stable catalytic performance, and have lower costs. In 1998, Mitsui Chemicals successfully developed a non-metallocene catalyst, namely the phenoxyimine complex catalyst (FI catalyst, Chem. Lett., 1999, 10, 1065-1066), which attracted great interest from academia and industry. FI catalysts possess excellent catalytic performance, with a single active center, resulting in highly homogeneous products. Their diverse ligand structures allow for precise control of the molecular weight of polyolefin products. However, the morphology of polymers produced by homogeneous FI catalysts is difficult to control, leading to polymerization sticking. To address this issue and better adapt to existing slurry and gas-phase polymerization processes, loading is necessary.

[0004] Chinese patent applications CN1962702A and others disclose that silica gel can be used as a catalyst support for FI (fiber oxidizing) catalysts. However, numerous studies have shown that silica gel supports typically require rigorous pretreatment (such as high-temperature heating or reaction with chemical reagents) to remove harmful groups on the surface and prevent deactivation of the catalyst's active sites. Furthermore, the use of silica gel supports increases the ash content of polyolefin products, raising post-processing costs. CN107090055A and CN1288173C use polystyrene (PS) as an organic polymer support to load FI catalysts, exhibiting high catalytic activity and good molecular weight dispersibility index in the produced polyethylene. However, these applications require pretreatment such as vinylation of the FI ligands or nitration and amination of the polystyrene support, making catalyst preparation a complex process.

[0005] When using MgCl2-supported non-metallocene catalysts, Chinese patents CN102030844B and CN107501444B require the MgCl2 to first react with an alcohol to form a magnesium alkoxide adduct, thereby improving the loading rate and dispersibility of the non-metallocene catalyst. Furthermore, because anhydrous MgCl2 is hygroscopic, the pretreatment process must be effectively controlled when using it as a support; otherwise, unstable catalyst activity and poor reproducibility may occur. Therefore, developing efficient and stable MgCl2-supported FI catalysts is essential. Summary of the Invention

[0006] The purpose of this invention is to provide a MgCl2 supported titanium catalyst, its preparation method, and its application. The MgCl2 support is prepared by adopting an in-situ generation strategy and used to support the FI catalyst. The preparation method is simple and the composition is controllable. In addition, the MgCl2 supported titanium catalyst obtained after supporting the FI catalyst has high catalytic activity and can be used to prepare ultra-high molecular weight polyethylene, etc.

[0007] The objective of this invention can be achieved through the following technical solutions: In a first aspect, the present invention provides a method for preparing a MgCl2-supported titanium-based catalyst, comprising the following steps: S1. Under an inert atmosphere, the chloride and the magnesium-containing Grignard reagent are dissolved in a chlorine-containing organic solvent to obtain an organic solution of the chloride and an organic solution of the magnesium-containing Grignard reagent. S2. The organic solution of chloride is added dropwise to the organic solution of Grignard reagent containing magnesium source, reacted, separated, washed, and dried to obtain MgCl2 support; S3. Place the MgCl2 support obtained in S2 in a sealed container, add an organic medium, add an organoaluminum compound under an inert atmosphere, stir the reaction, and separate, wash and dry the resulting reaction mixture to obtain the active MgCl2 support. S4. Dissolve the FI catalyst in an organic medium to obtain an FI catalyst solution, and then add it dropwise to the active MgCl2 support obtained in S3 under an inert atmosphere. Stir the reaction, and then separate the solid and liquid products, wash and dry them to obtain a MgCl2 supported titanium catalyst.

[0008] Furthermore, in S1, the chloride is one or more of silicon tetrachloride, methyltrichlorosilane, vinyltrichlorosilane, 3-chloropropyltrichlorosilane, phenyltrichlorosilane, p-toluenetrichlorosilane, p-chlorophenyltrichlorosilane, dimethyldichlorosilane, dichlorodiethylsilane, chloroform, and carbon tetrachloride.

[0009] Furthermore, in S1, the Grignard reagent containing the magnesium source is one or more of methyl magnesium chloride, ethyl magnesium chloride, isopropyl magnesium chloride, tert-butyl magnesium chloride, allyl magnesium chloride, benzyl magnesium chloride, phenyl magnesium chloride, o-tolyl magnesium chloride, 4-methoxyphenyl magnesium chloride, p-tolyl magnesium chloride, 2,5-dimethoxyphenyl magnesium chloride, and vinyl magnesium chloride.

[0010] Furthermore, in S1, the chlorinated organic solvent is selected from one or more of chlorobenzene, o-dichlorobenzene, p-dichlorobenzene, and 1,2-dichloroethane.

[0011] Furthermore, in S2, the molar ratio of the magnesium-containing Grignard reagent to the chloride is 1:(1.0~3.0).

[0012] Furthermore, in S2, the reaction is carried out under an inert atmosphere, at a temperature of -20 to 100°C, for a time of 1 to 36 hours.

[0013] Furthermore, in S3, the amount of MgCl2 support and organoaluminum compound added satisfies the following condition: the molar ratio of Mg to Al is 1:(1.0~10.0). The temperature for the stirred reaction is 20~180℃, and the time is 1~24h. Specifically, the stirring speed can be 100~3000 rpm.

[0014] Furthermore, in S3, the organoaluminum compound is one or a mixture of several selected from methylaluminoxane, modified methylaluminoxane, ethylaluminoxane, n-butylaluminoxane, or isopropylaluminoxane. Methylaluminoxane or ethylaluminoxane is preferred.

[0015] Furthermore, in S4, the weight ratio of the FI catalyst to the active MgCl2 support is 1:10~100; The temperature of the stirring reaction in S4 is 0~100℃, and the time is 1~48h.

[0016] Furthermore, the inert atmosphere in S1 to S4 is provided by nitrogen or argon, etc.

[0017] Furthermore, the organic medium can be one or two of tetrahydrofuran, diethyl ether, toluene, benzene, chloroform, dichloromethane, petroleum ether, n-hexane, and n-heptane.

[0018] Furthermore, in S4, the chemical structural formula of the FI catalyst is: , R 1 ~R 4 Each of the following is independent: hydrogen, C1 to C2. 10 Alkyl, cumyl, alkoxy, silyl, C7-C6 structures (linear, branched, or cyclic). 20Mono- or polyaryl-substituted alkyl groups, or halogens; R 5 For C1~C 10 Alkyl groups with straight, branched, or cyclic structures, C6–C6 10 Mono- or polyalkyl, halogen-substituted or unsubstituted benzyl groups; R 6 For C1~C 10 Alkyl, halogen-substituted or unsubstituted aryl groups with straight-chain, branched or cyclic structures; R 7 It is a halogen, preferably chlorine; M is a group IVB element, preferably titanium.

[0019] Furthermore, in S4, the structural formula of the FI catalyst is any one of the following a1 to a9: .

[0020] The catalysts a1 to a9 mentioned above are all commonly used FI catalysts in this field, and their sources will not be described in detail in this invention. Specifically, a1 and a2 can be prepared with reference to Eur. J. Inorg. Chem. 2005, 2100-2109; a3 to a9 can be prepared with reference to top organomet chem 2009, 26, 3-46.

[0021] In a second aspect, the present invention provides a MgCl2 supported titanium catalyst, which is prepared by the preparation method described in the first aspect above.

[0022] In a third aspect, the present invention provides an application of a MgCl2-supported titanium catalyst in the catalytic homopolymerization or copolymerization of olefins.

[0023] Furthermore, in application, the MgCl2-supported titanium catalyst is used as the main catalyst, and an alkyl aluminum compound is used as a co-catalyst to enable organic polymer monomers to undergo slurry polymerization, gas-phase polymerization, or solution polymerization in an organic medium; the organic medium in the polymerization process is selected from one or more of n-heptane, n-hexane, petroleum ether, toluene, benzene, tetrahydrofuran, and dichloromethane.

[0024] Furthermore, this catalyst is used to catalyze the homopolymerization of ethylene, or in combination with... -Olefin copolymerization, the - The olefin is selected from one or more of propylene, 1-butene, 1-hexene, 1-octene or norbornene.

[0025] Furthermore, the polymers prepared by catalytic olefin polymerization can have a viscosity-average molecular weight of 50,000 to 10 million and a molecular weight distribution of 2.0 to 5.0.

[0026] Compared with the prior art, the present invention has the following advantages: (1) Compared with conventional non-in-situ prepared magnesium chloride carriers, the MgCl2 carrier used in this invention is prepared in-situ using Grignard reagent and chloride. The carrier can be put into use without multiple pretreatment steps, and the active sites are uniform and stable. (2) The MgCl2 supported titanium catalyst of the present invention can effectively adjust the structure and morphology of the support by changing the Grignard reagent and chloride type, which is beneficial to adjust the catalytic activity of the titanium catalyst after loading and improve the particle morphology and molecular weight distribution of the obtained polyethylene.

[0027] (3) The MgCl2 supported titanium catalyst of the present invention has a narrower molecular weight distribution of polyethylene compared with the supported TiCl4 catalyst. Compared with the supported titanium metal catalyst, the catalyst has higher activity and the resulting polyethylene has a higher molecular weight, showing unique advantages. Attached Figure Description

[0028] Figure 1 SEM images of catalyst 1 prepared in Examples 1-5; Figure 2 The images are scanning electron microscope (SEM) images of polyethylene prepared by catalyst 1 in Examples 2-4. Detailed Implementation

[0029] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. These embodiments are based on the technical solution of the present invention and provide detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments.

[0030] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0031] As used herein, the terms "and / or," "or / and," and "and / or" encompass any one of two or more of the related listed items, as well as any and all combinations of the related listed items. These arbitrary and all combinations include any two related listed items, any more related listed items, or a combination of all related listed items. It should be noted that when at least three items are connected using at least two conjunctions selected from "and / or," "or / and," and "and / or," it should be understood that, in this application, the technical solution undoubtedly includes solutions connected by "logical AND," and also undoubtedly includes solutions connected by "logical OR."

[0032] In this application, the technical features described in an open-ended manner include both closed technical solutions consisting of the listed features and open technical solutions that include the listed features.

[0033] In this application, numerical ranges are referred to as continuous unless otherwise specified, and include the minimum and maximum values ​​of the range, as well as every value between the minimum and maximum values. Furthermore, when the range refers to integers, it includes every integer between the minimum and maximum values ​​of the range. Additionally, when multiple ranges are provided to describe a feature or characteristic, the ranges may be merged. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all subranges to which they are incorporated.

[0034] This document only specifically discloses some numerical ranges. However, any lower limit can be combined with any upper limit to form an unspecified range; and any lower limit can be combined with other lower limits to form an unspecified range, just as any upper limit can be combined with any other upper limit to form an unspecified range. Furthermore, each individually disclosed point or single value can itself serve as a lower or upper limit and be combined with any other point or single value or with other lower or upper limits to form an unspecified range.

[0035] Unless otherwise specified, the temperature parameters in this application may be either constant temperature processing or processing within a certain temperature range. The constant temperature processing allows temperature fluctuations within the precision range controlled by the instrument, such as ±5°C, ±4°C, ±3°C, ±2°C, or ±1°C.

[0036] In this document, the term "suitable" as used in phrases such as "suitable combination," "suitable method," and "any suitable method" refers to the ability to implement the technical solution of this application, solve the technical problem of this application, and achieve the expected technical effect of this application.

[0037] In this application, terms such as "further," "even more," and "particularly" are used for descriptive purposes and to indicate differences in content, but should not be construed as limiting the scope of protection of this application.

[0038] In this application, "optionally," "optionally," and "optional" mean that something is optional, that is, it means that it is selected from either "with" or "without." If there are multiple "optional" entries in a technical solution, unless otherwise specified, and there are no contradictions or mutual constraints, each "optional" entry shall be independent.

[0039] In the description of the application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0040] Unless otherwise specified, all preparations and tests described herein took place at 25°C.

[0041] The terms “comprising,” “including,” “containing,” “having,” “comprising,” or other variations thereof are intended to cover non-closed inclusion, and no distinction is made between these terms. The term “comprising” means that other steps and ingredients may be added without affecting the final result. The compositions and methods / processes of the present invention comprise, consist of, and substantially consist of the essential elements and limitations described herein, as well as any additional or optional ingredients, components, steps, or limitations described herein. No distinction is made between the terms “efficacy,” “performance,” “effect,” and “potency” herein.

[0042] Unless otherwise specified, all embodiments and optional embodiments of this application can be combined to form new technical solutions. Unless otherwise specified, all technical features and optional technical features of this application can be combined to form new technical solutions.

[0043] Unless otherwise specified, all steps of this application may be performed sequentially or randomly, but sequentially is preferred.

[0044] In this invention, a GN020 Ubbelohde viscometer was used to determine the viscosity-average molecular weight (Mv). Dry a 25 mL volumetric flask at 100 °C and cool it to room temperature. Accurately weigh 6 mg of polymer resin and 20 mg of antioxidant into the flask, and add decahydronaphthalene (naphthalene) until the liquid level is below the mark. Heat the mixture to 135 °C with stirring and maintain the temperature for 1.5 h to ensure complete dissolution of the polymer. Then add decahydronaphthalene preheated to 135 °C and bring the volume to the mark.

[0045] At 135 °C, the elution time t0 of pure decahydronaphthalene and the elution time t of the polymer solution were measured respectively; each sample was tested at least three times to ensure experimental reproducibility.

[0046] Finally, the viscosity-average molecular weight is calculated using the following formula: Relative viscosity η r = t / t0; Specific viscosity η sp =η r -1; Intrinsic viscosity [η] = [2(η sp - ln(η r ))] ¹ / ² / C; The Mark-Houwink equation is: ; The molecular weight distribution (PDI) of polyethylene samples was determined using high-temperature gel permeation chromatography (GPC). Part 1: Support preparation.

[0047] Example 1-1 Preparation method of support 1: Phenyl magnesium chloride and phenyl trichlorosilane were dissolved in 50 mL of chlorobenzene at a molar ratio of 1:2 under argon atmosphere. The chlorobenzene solution of phenyl trichlorosilane was added dropwise to the chlorobenzene solution of phenyl magnesium chloride at 5 °C, and the reaction was carried out at 65 °C for 1 hour. After the reaction was completed, the mixture was cooled to room temperature, filtered, washed, and dried under vacuum to obtain support 1.

[0048] Examples 1-2 Preparation method of support 2: Phenyl magnesium chloride and carbon tetrachloride were dissolved in 50 mL of chlorobenzene at a molar ratio of 1:2 under argon atmosphere. The carbon tetrachloride chlorobenzene solution was added dropwise to the phenyl magnesium chloride chlorobenzene solution at -5℃, and the reaction was carried out at 65℃ for 1 hour. After the reaction was completed, the mixture was cooled to room temperature, filtered, washed, and vacuum dried to obtain support 2.

[0049] Examples 1-3 Preparation method of support 3: Phenyl magnesium chloride and dimethyl dichlorosilane were dissolved in 50 mL of chlorobenzene at a molar ratio of 1:2 under argon atmosphere. The chlorobenzene solution of dimethyl dichlorosilane was added dropwise to the chlorobenzene solution of phenyl magnesium chloride at -5℃, and the reaction was carried out at 65℃ for 1 hour. After the reaction was completed, the mixture was cooled to room temperature, filtered, washed, and vacuum dried to obtain support 3.

[0050] Examples 1-4 Preparation method of support 4: Phenyl magnesium chloride, phenyl trichlorosilane, and dimethyl dichlorosilane were dissolved in 35 mL of chlorobenzene at a molar ratio of 1:1:1 under argon atmosphere. The mixed solution of dimethyl dichlorosilane and phenyl trichlorosilane was added dropwise to the chlorobenzene solution of phenyl magnesium chloride at -5℃, and the reaction was carried out at 65℃ for 1 hour. After the reaction was complete, the mixture was cooled to room temperature, filtered, washed, and vacuum dried to obtain support 4.

[0051] Examples 1-5 Preparation method of support 5: Methylmagnesium chloride and phenyltrichlorosilane were dissolved in 50 mL of chlorobenzene at a molar ratio of 1:2 under argon atmosphere. The chlorobenzene solution of phenyltrichlorosilane was added dropwise to the chlorobenzene solution of methylmagnesium chloride at 5°C, and the reaction was carried out at 65°C for 1 hour. After the reaction was completed, the mixture was cooled to room temperature, filtered, washed, and dried under vacuum to obtain support 5.

[0052] Examples 1-6 Compared with Examples 1-1, most of them are the same, except that the molar ratio of phenyl magnesium chloride and phenyl trichlorosilane is adjusted to 1:1; The reaction temperature was adjusted to -20℃ and the reaction time was adjusted to 36 hours.

[0053] Examples 1-7 Compared with Examples 1-1, most of them are the same, except that the molar ratio of phenyl magnesium chloride and phenyl trichlorosilane is adjusted to 1:3; The reaction temperature was adjusted to 100℃ and the reaction time was adjusted to 2 hours.

[0054] Part Two: Catalyst Preparation Example 2-1 Preparation method of catalyst 1: Weigh 500 mg of support 1 into a Schlenk tube in a glove box. Under an argon atmosphere, add toluene (10 mL) and methylaluminoxane (MAO) (400 mg) sequentially, and stir gently at 80°C for 3 hours. After filtration, wash 2-3 times with toluene, vacuum dry, and transfer to a glove box. Add dropwise 10 mL of a toluene solution of FI catalyst a4 (10 mg) to the container, and stir gently at 80°C for 3 hours. After filtration, wash 2-3 times with toluene, and vacuum dry to obtain catalyst 1.

[0055] Figure 1 This is a scanning electron microscope (SEM) image of catalyst 1 prepared in Example 2-1. Figure 1 The scanning electron microscope image shows that catalyst 1 has a spherical porous particulate structure.

[0056] Example 2-2 Preparation method of catalyst 2: Weigh 500 mg of support 2 into a Schlenk tube in a glove box. Under an argon atmosphere, add toluene (10 mL) and methylaluminoxane (MAO) (400 mg) sequentially, and stir gently at 80°C for 3 hours. After filtration, wash 2-3 times with toluene, vacuum dry, and transfer to a glove box. Add dropwise 10 mL of a toluene solution of FI catalyst a4 (10 mg) to the container, and stir gently at 80°C for 3 hours. After filtration, wash 2-3 times with toluene, and vacuum dry to obtain catalyst 2.

[0057] Example 2-3 Preparation method of catalyst 3: Weigh 500 mg of support 3 into a Schlenk tube in a glove box. Under an argon atmosphere, add toluene (10 mL) and methylaluminoxane (MAO) (400 mg) sequentially, and stir gently at 80°C for 3 hours. After filtration, wash 2-3 times with toluene, dry under vacuum, and transfer to a glove box. Add dropwise 10 mL of a toluene solution of FI catalyst a4 (10 mg) to the container, and stir gently at 80°C for 3 hours. After filtration, wash 2-3 times with toluene, and dry under vacuum to obtain catalyst 3.

[0058] Examples 2-4 Preparation method of catalyst 4: Weigh 500 mg of support 4 into a Schlenk tube in a glove box. Under an argon atmosphere, add toluene (10 mL) and methylaluminoxane (MAO) (400 mg) sequentially, and stir gently at 80°C for 3 hours. After filtration, wash 2-3 times with toluene, dry under vacuum, and transfer to a glove box. Add dropwise 10 mL of a toluene solution of FI catalyst a4 (10 mg) to the container, and stir gently at 80°C for 3 hours. After filtration, wash 2-3 times with toluene, and dry under vacuum to obtain catalyst 4.

[0059] Examples 2-5 Preparation method of catalyst 5: Weigh 500 mg of support 5 into a Schlenk tube in a glove box. Under an argon atmosphere, add toluene (10 mL) and methylaluminoxane (MAO) (400 mg) sequentially, and stir gently at 80°C for 3 hours. After filtration, wash 2-3 times with toluene, dry under vacuum, and transfer to a glove box. Add dropwise 10 mL of a toluene solution of FI catalyst a4 (10 mg) to the container, and stir gently at 80°C for 3 hours. After filtration, wash 2-3 times with toluene, and dry under vacuum to obtain catalyst 5.

[0060] Examples 2-6 Preparation method of catalyst 6: Weigh 500 mg of support 1 into a Schlenk tube in a glove box. Add toluene (10 mL) and butylaluminoxane (400 mg) sequentially under an argon atmosphere, and stir gently at 80°C for 3 hours. After filtration, wash 2-3 times with toluene, dry under vacuum, and transfer to a glove box. Add dropwise 10 mL of a toluene solution of FI catalyst a4 (10 mg) to the container, and stir gently at 80°C for 3 hours. After filtration, wash 2-3 times with toluene, and dry under vacuum to obtain catalyst 6.

[0061] Examples 2-7 Preparation method of catalyst 7: Weigh 500 mg of support 1 into a Schlenk tube in a glove box. Under an argon atmosphere, add toluene (10 mL) and methylaluminoxane (MAO) (400 mg) sequentially, and stir gently at 80°C for 3 hours. After filtration, wash 2-3 times with toluene, dry under vacuum, and transfer to a glove box. Add 10 mL of a toluene solution of FI catalyst a7 (10 mg) dropwise to the container, and stir gently at 80°C for 3 hours. After filtration, wash 2-3 times with toluene, and dry under vacuum to obtain catalyst 7.

[0062] Examples 2-8 Preparation method of catalyst 8: Weigh 100 mg of support 1 into a Schlenk tube in a glove box. Under an argon atmosphere, add toluene (10 mL) and methylaluminoxane (MAO) (400 mg) sequentially, and stir gently at 80°C for 3 hours. After filtration, wash 2-3 times with toluene, dry under vacuum, and transfer to a glove box. Add 10 mL of a toluene solution of FI catalyst a4 (10 mg) dropwise to the container, and stir gently at 80°C for 3 hours. After filtration, wash 2-3 times with toluene, and dry under vacuum to obtain catalyst 8.

[0063] Examples 2-9 Preparation method of catalyst 9: Weigh 1.0 g of support 1 into a Schlenk tube in a glove box. Under an argon atmosphere, add toluene (10 mL) and methylaluminoxane (MAO) (400 mg) sequentially, and stir gently at 80°C for 3 hours. After filtration, wash 2-3 times with toluene, dry under vacuum, and transfer to a glove box. Add 10 mL of a toluene solution of FI catalyst a4 (10 mg) dropwise to the container, and stir gently at 80°C for 3 hours. After filtration, wash 2-3 times with toluene, and dry under vacuum to obtain catalyst 9.

[0064] Example 2-10 Compared with Example 2-1, most of them are the same, except that the amount of methylaluminoxane (MAO) is adjusted so that the molar ratio of Mg to Al is 1:1, and the subsequent stirring reaction temperature is adjusted to 20°C and the time is adjusted to 24h. The amount of FI catalyst a4 was adjusted to 5 mg, and the reaction temperature was adjusted to 0 °C and the reaction time was adjusted to 48 h.

[0065] Example 2-11 Compared with Example 2-1, most of them are the same, except that the amount of methylaluminoxane (MAO) is adjusted so that the molar ratio of Mg to Al is 1:10, and the subsequent stirring reaction temperature is adjusted to 180°C and the time is adjusted to 1 hour. The amount of FI catalyst a4 was adjusted to 50 mg, and the reaction temperature was adjusted to 100 °C and the reaction time was adjusted to 1 h.

[0066] Part Three: Catalysts for Ethylene Homopolymerization Example 3-1 Catalyst 1 obtained in Example 2-1 was used for the catalytic homopolymerization of ethylene. The specific process was as follows: Under nitrogen protection, 1000 mL of n-hexane and 0.5 g of triethylaluminum were added to a stainless steel polymerization reactor. The reactor temperature was adjusted to 70°C and kept stable. 10.0 mg of catalyst 1, suspended in n-heptane, was weighed and added to the reactor. The ethylene pressure was rapidly adjusted to 1.0 MPa and timing was started, maintaining a constant ethylene pressure throughout the polymerization process. After 2 h of reaction, the ethylene gas supply was stopped, and the ethylene gas in the polymerization reactor was slowly released. The mixture was filtered to obtain white solid polyethylene. Vacuum drying was performed until constant weight. Yield: 110.5 g, Activity: 11050 g PE / gCat, Viscosity-average molecular weight M of the obtained polyethylene... v = 3.1×10 6 g / mol, molecular weight distribution PDI is 3.5.

[0067] Figure 2 This is a scanning electron microscope (SEM) image of polyethylene prepared based on catalyst 1 in Example 3-1. From... Figure 2 It can be seen that the polyethylene produced is a spherical solid particle with a small amount of filamentous structure on the surface.

[0068] Example 3-2 Catalyst 2 obtained in Example 2-2 was used for the catalytic homopolymerization of ethylene. The specific process was as follows: Under nitrogen protection, 1000 mL of n-hexane and 0.5 g of triethylaluminum were added to a stainless steel polymerization reactor. The reactor temperature was adjusted to 70°C and kept stable. 10.0 mg of catalyst 2, suspended in n-heptane, was weighed and added to the reactor. The ethylene pressure was rapidly adjusted to 1.0 MPa and timing was started, maintaining a constant ethylene pressure throughout the polymerization process. After 2 h of reaction, the ethylene gas supply was stopped, and the ethylene gas in the polymerization reactor was slowly released. The mixture was filtered to obtain white solid polyethylene. Vacuum drying was performed until constant weight. Yield: 151.8 g, Activity: 15180 g PE / gCat, Viscosity-average molecular weight M of the obtained polyethylene... v = 3.5 × 10 6 g / mol, molecular weight distribution PDI is 3.6.

[0069] Example 3-3 Catalyst 3 obtained in Examples 2-3 was used for the catalytic homopolymerization of ethylene. The specific process was as follows: Under nitrogen protection, 1000 mL of n-hexane and 0.5 g of triethylaluminum were added to a stainless steel polymerization reactor. The reactor temperature was adjusted to 70°C and kept stable. 10.0 mg of catalyst 3, suspended in n-heptane, was weighed and added to the reactor. The ethylene pressure was rapidly adjusted to 1.0 MPa and timing was started, maintaining a constant ethylene pressure throughout the polymerization process. After 2 h of reaction, the ethylene gas supply was stopped, and the ethylene gas in the polymerization reactor was slowly released. The mixture was filtered to obtain white solid polyethylene. Vacuum drying was performed until constant weight. Yield: 159.3 g, Activity: 15930 g PE / gCat, Viscosity-average molecular weight M of the obtained polyethylene... v = 4.1×10 6 g / mol, molecular weight distribution (PDI) is 3.8.

[0070] Examples 3-4 Catalyst 4 obtained in Examples 2-4 was used for the catalytic homopolymerization of ethylene. The specific process was as follows: Under nitrogen protection, 1000 mL of n-hexane and 0.5 g of triethylaluminum were added to a stainless steel polymerization reactor. The reactor temperature was adjusted to 70°C and kept stable. 10.0 mg of catalyst 4, suspended in n-heptane, was weighed and added to the reactor. The ethylene pressure was rapidly adjusted to 1.0 MPa and timing was started, maintaining a constant ethylene pressure throughout the polymerization process. After 2 h of reaction, the ethylene gas supply was stopped, and the ethylene gas in the polymerization reactor was slowly released. The mixture was filtered to obtain white solid polyethylene. It was then vacuum dried until constant weight. Yield: 123.5 g, Activity: 12350 g PE / gCat, Viscosity-average molecular weight M of the obtained polyethylene... v = 3.9×10 6 g / mol, molecular weight distribution PDI is 3.6.

[0071] Examples 3-5 Catalyst 1 obtained in Example 2-1 was used for the catalytic homopolymerization of ethylene. The specific process was as follows: Under nitrogen protection, 1000 mL of n-hexane and 0.2 g of triethylaluminum were added to a stainless steel polymerization reactor. The reactor temperature was adjusted to 70°C and kept stable. 10.0 mg of catalyst 1, suspended in n-heptane, was weighed and added to the reactor. The ethylene pressure was rapidly adjusted to 1.0 MPa and timing was started, maintaining a constant ethylene pressure throughout the polymerization process. After 2 h of reaction, the ethylene gas supply was stopped, and the ethylene gas in the polymerization reactor was slowly released. The mixture was filtered to obtain white solid polyethylene. It was then vacuum dried until constant weight. Yield: 95.5 g, Activity: 9550 g PE / gCat, Viscosity-average molecular weight M of the obtained polyethylene... v = 8.1×10 6 g / mol, molecular weight distribution (PDI) is 3.8.

[0072] Examples 3-6 Catalyst 5 obtained in Examples 2-5 was used for the catalytic homopolymerization of ethylene. The specific process was as follows: Under nitrogen protection, 1000 mL of n-hexane and 0.5 g of triethylaluminum were added to a stainless steel polymerization reactor. The reactor temperature was adjusted to 70°C and kept stable. 10.0 mg of catalyst 5, suspended in n-heptane, was weighed and added to the reactor. The ethylene pressure was rapidly adjusted to 1.0 MPa and timing was started, maintaining a constant ethylene pressure throughout the polymerization process. After 2 h of reaction, the ethylene gas supply was stopped, and the ethylene gas in the polymerization reactor was slowly released. The mixture was filtered to obtain white solid polyethylene. It was then vacuum dried until constant weight. Yield: 105.0 g, Activity: 10500 g PE / gCat, Viscosity-average molecular weight M of the obtained polyethylene. v = 3.3 × 10 6 g / mol, molecular weight distribution PDI is 3.6.

[0073] Examples 3-7 Catalyst 6 obtained in Examples 2-6 was used for the catalytic homopolymerization of ethylene. The specific process was as follows: Under nitrogen protection, 1000 mL of n-hexane and 0.5 g of triethylaluminum were added to a stainless steel polymerization reactor. The reactor temperature was adjusted to 70°C and kept stable. 10.0 mg of catalyst 6, suspended in n-heptane, was weighed and added to the reactor. The ethylene pressure was rapidly adjusted to 1.0 MPa and timing was started, maintaining a constant ethylene pressure throughout the polymerization process. After 2 h of reaction, the ethylene gas supply was stopped, and the ethylene gas in the polymerization reactor was slowly released. The mixture was filtered to obtain white solid polyethylene. It was then vacuum dried until constant weight. Yield: 101.5 g, Activity: 10150 g PE / gCat, Viscosity-average molecular weight M of the obtained polyethylene... v = 3.2×10 6 g / mol, molecular weight distribution PDI is 3.5.

[0074] Examples 3-8 Catalyst 7 obtained in Examples 2-7 was used for the catalytic homopolymerization of ethylene. The specific process was as follows: Under nitrogen protection, 1000 mL of n-hexane and 0.5 g of triethylaluminum were added to a stainless steel polymerization reactor. The reactor temperature was adjusted to 70°C and kept stable. 10.0 mg of catalyst 7, suspended in n-heptane, was weighed and added to the reactor. The ethylene pressure was rapidly adjusted to 1.0 MPa and timing was started, maintaining a constant ethylene pressure throughout the polymerization process. After 2 h of reaction, the ethylene gas supply was stopped, and the ethylene gas in the polymerization reactor was slowly released. The mixture was filtered to obtain white solid polyethylene. It was then vacuum dried until constant weight. Yield: 135.0 g, Activity: 13500 g PE / gCat, Viscosity-average molecular weight M of the obtained polyethylene... v = 1.5×10 6 g / mol, molecular weight distribution (PDI) is 3.8.

[0075] Examples 3-9 Catalyst 8 obtained in Examples 2-8 was used for the catalytic homopolymerization of ethylene. The specific process was as follows: Under nitrogen protection, 1000 mL of n-hexane and 0.5 g of triethylaluminum were added to a stainless steel polymerization reactor. The reactor temperature was adjusted to 70°C and kept stable. 10.0 mg of catalyst 8, suspended in n-heptane, was weighed and added to the reactor. The ethylene pressure was rapidly adjusted to 1.0 MPa and timing was started, maintaining a constant ethylene pressure throughout the polymerization process. After 2 h of reaction, the ethylene gas supply was stopped, and the ethylene gas in the polymerization reactor was slowly released. The mixture was filtered to obtain white solid polyethylene. Vacuum drying was performed until constant weight. Yield: 256.0 g, Activity: 25600 g PE / gCat, Viscosity-average molecular weight M of the obtained polyethylene... v = 2.9×10 6 g / mol, molecular weight distribution (PDI) is 3.8.

[0076] Examples 3-10 Catalyst 9 obtained in Examples 2-9 was used to catalyze the homopolymerization of ethylene. The specific process was as follows: Under nitrogen protection, 1000 mL of n-hexane and 0.5 g of triethylaluminum were added to a stainless steel polymerization reactor. The reactor temperature was adjusted to 70°C and kept stable. 10.0 mg of catalyst 9, suspended in n-heptane, was weighed and added to the reactor. The ethylene pressure was rapidly adjusted to 1.0 MPa and timing was started, maintaining a constant ethylene pressure throughout the polymerization process. After 2 h of reaction, the ethylene gas supply was stopped, and the ethylene gas in the polymerization reactor was slowly released. The mixture was filtered to obtain white solid polyethylene. Vacuum drying was performed until constant weight. Yield: 64.0 g, Activity: 6400 g PE / gCat, Viscosity-average molecular weight M of the obtained polyethylene... v = 3.0 × 10 6 g / mol, molecular weight distribution PDI is 3.6.

[0077] Comparative Example 1: Compared to Example 2-1, the FI catalyst is replaced with titanium tetrachloride (TiCl4) support, and the preparation method of catalyst 10 is provided accordingly: Weigh 500 mg of support 1 into a Schlenk tube in a glove box, add n-hexane (10 mL), and add TiCl4 (1000 mg) dropwise to the container. Stir gently at 80°C for 3 hours. After filtration, wash 2-3 times with n-hexane, and dry under vacuum to obtain catalyst 10.

[0078] The obtained catalyst 10 was used to catalyze the homopolymerization of ethylene. The specific process was as follows: Under nitrogen protection, 1000 mL of n-hexane and 0.5 g of triethylaluminum were added to a stainless steel polymerization reactor. The reactor temperature was adjusted to 70℃ and kept stable. 10.0 mg of catalyst 5, suspended in n-heptane, was weighed and added to the reactor. The ethylene pressure was rapidly adjusted to 1.0 MPa and timing was started, maintaining a constant ethylene pressure throughout the polymerization process. After 2 h of reaction, the ethylene gas supply was stopped, and the ethylene gas in the polymerization reactor was slowly released. The mixture was filtered to obtain white solid polyethylene. It was then vacuum dried until constant weight. Yield: 141.5 g, Activity: 14150 g PE / g Cat, Viscosity-average molecular weight M of the obtained polyethylene... v = 3.7 × 10 6 g / mol, molecular weight distribution PDI is 4.8.

[0079] Comparative Example 2: Compared to Example 2-1, the FI catalyst was replaced with a dicyclopentadienyl titanium dichloride support. The preparation method of catalyst 11 is as follows: Weigh 500 mg of support 1 into a Schlenk tube in a glove box, and add toluene (10 mL) and MAO (400 mg) sequentially. Stir gently at 110°C for 3 hours. After filtration, wash 2-3 times with toluene, vacuum dry, and transfer to a glove box. Add dropwise 10 mL of a toluene solution containing 10 mg of dicyclopentadienyl titanium dichloride to the container, and stir gently at room temperature for 2 hours. After filtration, wash 2-3 times with toluene, and vacuum dry to obtain catalyst 11.

[0080] The obtained catalyst 11 was used to catalyze the homopolymerization of ethylene. The specific process was as follows: Under nitrogen protection, 1000 mL of n-hexane and 0.5 g of triethylaluminum were added to a stainless steel polymerization reactor. The reactor temperature was adjusted to 70℃ and kept stable. 10.0 mg of catalyst 6, suspended in n-heptane, was weighed and added to the reactor. The ethylene pressure was rapidly adjusted to 1.0 MPa and timing was started, maintaining a constant ethylene pressure throughout the polymerization process. After 2 h of reaction, the ethylene gas supply was stopped, and the ethylene gas in the polymerization reactor was slowly released. The mixture was filtered to obtain white solid polyethylene. It was then vacuum dried until constant weight. Yield: 78.5 g, Activity: 7850 g PE / g Cat, Viscosity-average molecular weight M of the obtained polyethylene... v = 5.4 × 10 5 g / mol, molecular weight distribution PDI is 2.6.

[0081] Comparative Examples 1 and 2 with Example 3-1 reveals that, while Comparative Example 1, with its ZN catalyst, also exhibits high activity, the resulting polyethylene has a significantly wider molecular weight distribution. Comparative Example 2, with its metallocene catalyst, produces a polyethylene with a narrower molecular weight distribution but a lower molecular weight, falling outside the category of ultra-high molecular weight polyethylene. Therefore, to obtain ultra-high molecular weight polyethylene with a narrow molecular weight distribution, the FI catalyst is essential for the in-situ prepared magnesium chloride support provided by this invention; other conventional catalyst active components cannot meet this requirement.

[0082] Comparative Example 3: The process was largely the same as in Example 2-1, except that commercially available magnesium chloride (purchased from Aladdin) was used instead of support 1. The resulting catalyst was designated as catalyst 12, and catalyst 12 was then used to catalyze the homopolymerization of ethylene according to the method in Example 3-1. Yield: 55.2 g, Activity: 5520 g PE / g Cat, and the viscosity-average molecular weight M of the obtained polyethylene was... v = 3.6 × 10 6 g / mol, molecular weight distribution (PDI) is 3.8.

[0083] Comparative analysis of Comparative Example 3 and Example 3-1 shows that Example 3-1, which uses in-situ generated magnesium chloride as a support, exhibits significantly higher catalytic activity and a narrower molecular weight distribution in the ultra-high molecular weight polyethylene product. Possible reasons for this include: firstly, the in-situ generated magnesium chloride may be predominantly in the highly active γ-MgCl2 crystal form. Chloride helps inhibit crystal growth and stabilizes the metastable γ-MgCl2 structure, resulting in larger interlayer spacing, a higher proportion of highly active crystal faces, and moderate surface acidity, thereby significantly improving the loading efficiency and active center utilization of the FI catalyst; secondly, the in-situ generated magnesium chloride, due to the explosive nucleation process during preparation, facilitates the formation of loose nanocrystalline aggregates, ultimately resulting in a sponge-like or porous support (e.g., ...). Figure 1 (As shown) This porous structure facilitates the diffusion of ethylene monomers and co-catalysts (MAO) into the support, allowing the internal active centers to effectively participate in the reaction. It also promotes polymer chain growth and desorption, thus exhibiting high activity.

[0084] Table 1 Catalytic performance of each example and comparative example

[0085] The above description of the embodiments is provided to enable those skilled in the art to understand and use the invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the invention should be within the protection scope of the present invention.

Claims

1. A method for preparing a MgCl2-supported titanium-based catalyst, characterized in that, Includes the following steps: S1. Under an inert atmosphere, the chloride and the magnesium-containing Grignard reagent are dissolved in a chlorine-containing organic solvent to obtain an organic solution of the chloride and an organic solution of the magnesium-containing Grignard reagent. S2. The organic solution of chloride is added dropwise to the organic solution of Grignard reagent containing magnesium source, reacted, separated, washed, and dried to obtain MgCl2 support; S3. Place the MgCl2 support obtained in S2 in a sealed container, add an organic medium, add an organoaluminum compound under an inert atmosphere, stir the reaction, and separate, wash and dry the resulting reaction mixture to obtain the active MgCl2 support. S4. Dissolve the FI catalyst in an organic medium to obtain an FI catalyst solution, and then add it dropwise to the active MgCl2 support obtained in S3 under an inert atmosphere. Stir the reaction, and then separate the solid and liquid products, wash and dry them to obtain a MgCl2 supported titanium catalyst.

2. The method for preparing a MgCl2-supported titanium catalyst according to claim 1, characterized in that, In S1, the chloride is one or more of the following: silicon tetrachloride, methyltrichlorosilane, vinyltrichlorosilane, 3-chloropropyltrichlorosilane, phenyltrichlorosilane, p-toluenetrichlorosilane, p-chlorophenyltrichlorosilane, dimethyldichlorosilane, dichlorodiethylsilane, chloroform, and carbon tetrachloride. The magnesium-containing Grignard reagent is one or more of the following: methyl magnesium chloride, ethyl magnesium chloride, isopropyl magnesium chloride, tert-butyl magnesium chloride, allyl magnesium chloride, benzyl magnesium chloride, phenyl magnesium chloride, o-tolyl magnesium chloride, 4-methoxyphenyl magnesium chloride, p-tolyl magnesium chloride, 2,5-dimethoxyphenyl magnesium chloride, and vinyl magnesium chloride. The chlorinated organic solvent is selected from one or more of chlorobenzene, o-dichlorobenzene, p-dichlorobenzene, and 1,2-dichloroethane.

3. The method for preparing a MgCl2-supported titanium catalyst according to claim 1, characterized in that, In S2, the molar ratio of the magnesium-containing Grignard reagent to the chloride is 1:(1.0~3.0). In S2, the reaction is carried out under an inert atmosphere, at a temperature of -20 to 100°C, for a time of 1 to 36 hours.

4. The method for preparing a MgCl2-supported titanium catalyst according to claim 1, characterized in that, In S3, the amount of MgCl2 support and organoaluminum compound added satisfies the following condition: the molar ratio of Mg to Al is 1:(1.0~10.0). The temperature for the stirring reaction is 20~180℃, and the time is 1~24h.

5. The method for preparing a MgCl2-supported titanium catalyst according to claim 1, characterized in that, In S3, the organoaluminum compound is one or a mixture of several of methylaluminoxane, modified methylaluminoxane, ethylaluminoxane, n-butylaluminoxane, or isopropylaluminoxane.

6. The method for preparing a MgCl2-supported titanium catalyst according to claim 1, characterized in that, In S4, the weight ratio of FI catalyst to active MgCl2 support is 1:10~100; The temperature of the stirring reaction in S4 is 0~100℃, and the time is 1~48h.

7. The method for preparing a MgCl2-supported titanium catalyst according to claim 1, characterized in that, In S4, the chemical structural formula of the FI catalyst is: ， R 1 ~R 4 Each of the following is independent: hydrogen, C1 to C2. 10 Alkyl, cumyl, alkoxy, silyl, C7-C6 structures (linear, branched, or cyclic). 20 Mono- or polyaryl-substituted alkyl groups, or halogens; R 5 For C1~C 10 Alkyl groups with straight, branched, or cyclic structures, C6–C6 10 Mono- or polyalkyl, halogen-substituted or unsubstituted benzyl groups; R 6 For C1~C 10 Alkyl, halogen-substituted or unsubstituted aryl groups with straight-chain, branched or cyclic structures; R 7 It is a halogen; M is an element of group IVB.

8. The method for preparing a MgCl2-supported titanium catalyst according to claim 1, characterized in that, In S4, the structural formula of the FI catalyst is any one of the following a1 to a9: 。 9. A MgCl2-supported titanium-based catalyst, characterized in that, It is prepared by the preparation method described in any one of claims 1-8.

10. The application of the MgCl2 supported titanium catalyst as described in claim 9, characterized in that, This catalyst is used to catalyze the homopolymerization or copolymerization of olefins.

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