Double-metallocene / single-metallocene supported catalyst as well as preparation method and application thereof

Abstract

The invention discloses a double-metallocene / single-metallocene supported catalyst and a preparation method and application thereof, and relates to the technical field of catalysts, the catalyst comprises a carrier, and a double-metallocene catalyst, a single-metallocene catalyst and a promoter which are supported on the carrier; the total weight ratio of the carrier to the double-metallocene catalyst and the single-metallocene catalyst is (2-100): 1; the weight ratio of the double metallocene catalyst to the single metallocene catalyst is (1-100): 1; the weight ratio of the double metallocene catalyst to the cocatalyst is 1: (1-80). The double-metallocene / single-metallocene supported catalyst provided by the invention has the advantages of simplicity and convenience in synthesis, good stability and low cost. The bimodal polyethylene resin can be prepared in a single reaction kettle without hydrogen regulation or addition of a comonomer.

Description

Technical Field

[0001] This invention relates to the field of catalyst technology, and more specifically, to a bis(c)- and monocrylocene metal-supported catalyst, its preparation method, and its application. Background Technology

[0002] Bimodal polyethylene refers to blends with a bimodal molecular weight distribution, comprising a low-molecular-weight, low-branched fraction and a high-molecular-weight, highly branched fraction. The high-molecular-weight fraction imparts good strength, toughness, and environmental stress cracking resistance (ESCR); while the low-molecular-weight fraction ensures the polymer's rigidity and provides lubrication to improve the resin's processability. Because bimodal polyethylene achieves a good balance between processability and performance, it has become an important direction for the high-performance development of polyolefin synthetic resins.

[0003] Currently, there are several main methods for preparing bimodal polyethylene: melt blending, tandem reactor method, and single reactor method. Among them, the tandem reactor method is the main method for industrial production of bimodal polyethylene and the technology is relatively mature; the single reactor method is a recent research hotspot for bimodal polyethylene, including bimetallic catalyst or mixed catalyst methods; the melt blending method is rarely used now because it is difficult to ensure uniform mixing.

[0004] Melt blending involves producing polymers with higher and lower molecular weights separately in two parallel reactors, then blending them in a specific ratio to control the molecular weight distribution. Strong stirring is required to achieve intermolecular blending and disperse the melt. However, the higher molecular weight component has poor flowability, making uniform mixing difficult and compromising product quality. This method is also less commonly used due to its high energy consumption and inconsistent product quality, as it requires heating polyethylene to a molten state and intense stirring.

[0005] The tandem reactor process is currently the main industrialized method for producing bimodal polyethylene. It uses two reactors in series to polymerize the product. The first and second reactors produce products with different molecular weights. By controlling different polymerization conditions in the two reactors, such as varying hydrogen partial pressure, polymerization temperature and time, and changing the comonomer ratio, a bimodal molecular weight distribution polyethylene can be obtained. For example, a lower molecular weight polymer can be produced in the first reactor through hydrogen conditioning, and then the polymer can be transferred to the second reactor for further hydrogen conditioning or without hydrogen addition to produce a higher molecular weight polymer. Currently, many companies both domestically and internationally use this method for bimodal polyethylene production, such as the slurry-based tandem reactor process developed by BP, Mitsui Chemicals, Solvay, and Hoechst, the Unipol II process developed by UCC, and the Borstar bimodal polyethylene production process developed by Borealis.

[0006] The production of bimodal polyethylene using a series reactor process is energy-intensive and therefore results in a higher product price, as the two reactors produce high-molecular-weight and low-molecular-weight resins respectively. In contrast, the single-reactor method offers advantages such as lower equipment investment, simpler operation, easier start-up and shutdown, and more uniform molecular-level mixing of high and low molecular weight products (leading to better product performance), making it an important research direction for bimodal polyethylene production. However, the development of bimetallic catalysts is challenging; currently, only Univation's BMC catalyst, using Prodiegy technology, has achieved industrial-scale application in a gas-phase process. Therefore, developing a bimetallic central catalyst is the core technology for producing bimodal polyethylene using the single-reactor bimodal process.

[0007] Total disclosed a method for preparing bimodal polyethylene using a composite of two chromium-based catalysts in patent US6015866A, resulting in polyethylene with good mechanical properties. ExxonMobil disclosed a method for preparing bimodal polyethylene by combining a non-metallic cyclohexane catalyst with organomagnesium and a carbonyl component in patent CN101070360A; this polyethylene exhibits improved resin expansion properties and can be used for blow molding. In patent CN1513002A, Mobil disclosed a method for preparing bimodal polyethylene with improved resistance to environmental stress cracking by combining a metallocene catalyst with a Ziegnerata catalyst. Dow Chemical disclosed a bimetallic catalyst combining non-metallocene chemistry with a zirconium cyclohexane compound in US20200024376A1, which exhibits improved processing properties.

[0008] In China, besides the Beijing Institute of Chemical Technology (BICT), the Chinese Academy of Sciences, Zhejiang University, and the Shanghai Research Institute of Chemical Industry have all invested in the research and development of bimetallic catalysts. BICT, in patent CN101225192A, loaded two post-transition metal compounds onto a magnesium compound to obtain polyethylene with a bimodal distribution. The Shanghai Research Institute of Chemical Industry, in patent CN102504058A, loaded two catalyst components onto a modified organic polymer to prepare bimodal polyethylene particles with high bulk density and uniform particle size. Zhejiang University, in patent CN103421138A, disclosed the preparation of bimodal polyethylene by combining bisphenoxyimine zirconium dichloride with a metallocene compound.

[0009] The mainstream industrial production of bimodal polyethylene using bimetallic catalysts currently employs a series reactor process, mainly combining zinc (Zn), metallocene, and post-transition metal catalysts. Zn catalysts, containing multiple active sites, easily compete with other catalysts, leading to mutual interference. Metallocene catalysts have only one active site, resulting in a narrow molecular weight distribution of the polymerized product. Post-transition metal catalysts are less sensitive to water and oxygen but are prone to residue sticking. The preparation of bimodal polyethylene using bimetallic catalysts requires the addition of α-olefin comonomers and is carried out under hydrogen-modulated conditions. Summary of the Invention

[0010] To address the problems existing in the prior art, this invention provides a bis(c)- and monoc)-metal-supported catalyst, its preparation method, and its applications. The bis(c)- and monoc)-metal-supported catalyst of this invention has the advantages of simple synthesis, good stability, and low cost. It does not require hydrogen conditioning or the addition of comonomers and can prepare bimodal polyethylene resin in a single reactor.

[0011] One of the objectives of this invention is to provide a bis(c)- or monocronocene metal-supported catalyst.

[0012] The diacensorcinate / monocene metal-supported catalyst of the present invention includes a support and a diacensorcinate metal catalyst, a monoocene metal catalyst and a co-catalyst supported on the support;

[0013] The weight ratio of the support to the total weight of the di- and mono-metallocene catalysts is (2-100):1;

[0014] The weight ratio of the di-metallocene catalyst to the mono-metallocene catalyst is (1-100):1;

[0015] The weight ratio of the dimorphocene catalyst to the co-catalyst is 1:(1-80).

[0016] In a preferred embodiment of the present invention:

[0017] The weight ratio of the support to the total weight of the di- and mono-metallocene catalysts is (2-20):1.

[0018] The weight ratio of the di-metallocene catalyst to the mono-metallocene catalyst is (5-50):1, preferably (10-20):1;

[0019] The weight ratio of the dimorphotropic catalyst to the co-catalyst is 1:(5-50), preferably 1:(5-15).

[0020] In a preferred embodiment of the present invention:

[0021] The carrier is at least one selected from silicon dioxide, alumina, aluminosilicate, inorganic clay, magnesium oxide, and magnesium dichloride; and / or,

[0022] The dicyclopentadienyl catalyst is at least one of Cp₂M₁X₁₂, IndCpM₂X₂₂, Et(Ind)₂M₃X₃₂, and Ind₂M₄X₄₂, wherein Cp is cyclopentadienyl, Ind is indene, Et is ethylene, M₁, M₂, M₃, and M₄ can be the same or different, and are independently one of Ti, Zr, and Hf, respectively; X₁, X₂, X₃, and X₄ can be the same or different, and are independently one of Cl, Br, and I, respectively; and / or,

[0023] The monoceramic catalyst is Me2Si(R4CpNR')MX and / or Me5CpM'X', wherein R is one of methyl, ethyl, or propyl; Cp is cyclopentadienyl; R' is one of methyl, ethyl, propyl, isopropyl, or tert-butyl; M is one of Ti, Zr, or Hf; X is one of Cl, Br, or I; M' is one of Ti, Zr, or Hf; and X' is one of Cl, Br, or I; and / or,

[0024] The cocatalyst is at least one of methylaluminoxane, modified methylaluminoxane, triethylaluminum, ethylaluminoxane, and isobutylaluminoxane.

[0025] In a preferred embodiment of the present invention:

[0026] The porosity of the carrier is 0.04–2 cm³. 3 / g, and / or, with a surface area of ​​10–500 m² 2 / g, and / or, average pore size is And / or, with an average particle size of 5–80 μm.

[0027] A second objective of this invention is to provide a method for preparing a bis(c)- or monoc)-metal supported catalyst as described in one objective of this invention.

[0028] The method for preparing the bis(cadhercinate) / monocercinate metal-supported catalyst of the present invention includes:

[0029] The di- and mono-metallocene catalysts were loaded onto a support pre-loaded with a catalyst using an impregnation method.

[0030] The preparation method of the bis(c)- and monoc)-metallic supported catalysts of the present invention employs an impregnation method. It mainly consists of two steps: first, loading the co-catalyst onto a support; second, loading the bis(c)- and monoc)-metallic catalysts onto the support pre-loaded with the co-catalysts.

[0031] In a preferred embodiment of the present invention, the method includes:

[0032] (1) Under a protective gas atmosphere, a portion of the co-catalyst solution was added to the carrier dispersion and heated to react, thereby obtaining a carrier dispersion loaded with the co-catalyst.

[0033] (2) Under a protective gas atmosphere, the di-metallocene catalyst and the mono-metallocene catalyst are dissolved in the remaining co-catalyst solution and then added to the carrier dispersion on which the co-catalyst is supported. The mixture is stirred and reacted, and after standing and separating into layers, it is filtered to obtain the supported catalyst. The filtration can be carried out by: after standing and separating into layers, the upper clear layer is filtered, and then the lower solid layer is filtered to obtain the supported catalyst in solid dry powder.

[0034] In a preferred embodiment of the present invention:

[0035] In step (1):

[0036] Based on the molar amount of aluminum in the co-catalyst, the concentration of the co-catalyst is 0.1–10 mmol / ml, preferably 0.1–5 mmol / ml; and / or,

[0037] The concentration of the carrier dispersion is 0.01–0.1 g / ml, preferably 0.01–0.05 g / ml; and / or,

[0038] The co-catalyst constitutes 50% to 85% of the total weight of the co-catalyst, preferably 70% to 85%; and / or,

[0039] The weight ratio of the carrier to the total cocatalyst is (1-100):1, preferably (1-10):1, and more preferably (1-2):1.

[0040] In a preferred embodiment of the present invention:

[0041] In step (2):

[0042] Based on the molar amount of aluminum in the co-catalyst, the concentration of the remaining co-catalyst is 0.1–3 mmol / ml, preferably 0.1–1 mmol / ml; and / or,

[0043] The weight ratio of the di-metallocene catalyst to the mono-metallocene catalyst is (1-100):1, preferably (5-50):1, more preferably (10-20):1; and / or,

[0044] The weight ratio of the dicelocene catalyst to the total co-catalyst is 1:(1-80), preferably 1:(5-50).

[0045] In a preferred embodiment of the present invention:

[0046] In step (1):

[0047] The solvent for the partial catalyst solution is at least one selected from toluene, dichloromethane, trichloromethane, and tetrahydrofuran; and / or,

[0048] The solvent of the carrier dispersion is at least one selected from benzene, toluene, xylene, monochlorobenzene, dichlorobenzene, trichlorobenzene, and monochlorotoluene; and / or,

[0049] The heating reaction is carried out at a temperature of 50–100°C and / or for a time of 1–3 hours.

[0050] In a preferred embodiment of the present invention:

[0051] In step (2):

[0052] The solvent for the remaining co-catalyst solution is at least one selected from toluene, dichloromethane, trichloromethane, and tetrahydrofuran; and / or,

[0053] The reaction temperature of the stirring reaction is 60–80°C, and / or the reaction time is 2–4 h.

[0054] A third objective of this invention is to provide the application of a bis(c)- or monoc)-metal supported catalyst as described in one objective of this invention, or a bis(c)- or monoc)-metal supported catalyst prepared by the preparation method described in another objective of this invention, in the catalytic polymerization of olefins. Preferably, the olefin polymerization reaction is a homopolymerization of ethylene.

[0055] The bis-metallic / monocene metal-supported catalysts of the present invention can provide the high molecular weight fraction of olefin polymerization; the mono-metallic catalyst can provide the low molecular weight fraction of olefin polymerization, that is, the polymerized polyolefin has a bimodal molecular weight distribution.

[0056] The bis(c)- and monoc)-metal-supported catalysts of this invention have the advantages of simple synthesis, good stability, and low cost. Bimodal polyethylene resin can be prepared in a single reactor without the need for hydrogen conditioning or the addition of comonomers. The polymerization activity of the bis(c)- and monoc)-metal-supported catalysts of this invention is greater than 10. 6 g / mol·h, approximately 1×10 6 ~3×10 6 g / mol·h; the polymers prepared by the bis(c)- and monocrylocene metal-supported catalysts of this invention have a weight-average molecular weight greater than 10 g / mol·h. 5 Approximately 1×10 5 ~5×10 5 The molecular weight distribution of bimodal polyethylene is greater than 5.0, approximately 5–6. Attached Figure Description

[0057] Figure 1The GPC test spectrum of bimodal polyethylene prepared using the bis-metallocene catalyst MⅠ / mono-metallocene catalyst MⅡ supported catalyst of Example 1 is shown.

[0058] Figure 2 The GPC test spectrum of unimodal polyethylene prepared using the bis-metallocene catalyst MⅠ supported catalyst of Comparative Example 1 is shown.

[0059] Figure 3 The GPC test spectrum of unimodal polyethylene prepared using the monoceramic catalyst MⅡ supported catalyst of Comparative Example 2 is shown.

[0060] from Figure 1 It can be seen that the polyethylene resin prepared using the bis(cadmium) / monocene metal-supported catalyst of the present invention exhibits a bimodal distribution. Detailed Implementation

[0061] The present invention will now be described in detail with reference to the accompanying drawings and embodiments. It should be noted that the following embodiments are only used to further illustrate the present invention and should not be construed as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the content of the present invention are still within the scope of protection of the present invention.

[0062] The raw materials used in the embodiments and comparative examples of this invention are all commercially available products.

[0063] The specific information of the di-metallocene and mono-metallocene catalysts used in the embodiments and comparative examples of this invention is shown in Table 1 below:

[0064] Table 1

[0065]

[0066] The structural formula of the dicelocene metallocene catalyst MⅠ is:

[0067]

[0068] The NMR spectra of the above-mentioned dicelocene metal catalyst MⅠ are as follows: 1 ¹H NMR (600MHz, CDCl₃) δ 7.66 (dd, J = 8.7, 1.0 Hz, 2H), 7.51–7.47 (m, 2H), 7.34–7.31 (m, 2H), 7.22–7.19 (m, 2H), 6.59 (dd, J = 3.3, 0.9 Hz, 2H), 6.21 (d, J = 3.4 Hz, 2H), 3.82–3.69 (m, 4H). The NMR characterization results are consistent with the molecular structure.

[0069] The structural formulas of monoceramic metal catalysts MⅡ and MⅢ are as follows:

[0070]

[0071] The NMR spectra of the above-mentioned monoceramic metal catalyst MⅡ are as follows: 1 ¹H NMR (600MHz, CDCl₃) δ 2.24 (s, 6H), 2.14 (s, 6H), 1.43 (s, 9H), 0.71 (s, 6H), NMR characterization results are consistent with molecular structure;

[0072] The NMR spectra of the aforementioned monoceramic metal catalyst MⅢ are as follows: 1 1H NMR (600MHz, C6D6) δ1.93 (s, 15H), the NMR characterization results are consistent with the molecular structure.

[0073] The tests in the embodiments and comparative examples of this invention were performed using the following methods:

[0074] (1) Nuclear magnetic resonance method: A Bruker Avance III 600MHz nuclear magnetic resonance spectrometer (NMR) with a 10 mm probe was used. The solvents used were deuterated chloroform and deuterated benzene.

[0075] (2) Molecular weight (M) w M n M z ) and molecular weight distribution PDI(M w / M n The determination was performed using gel permeation chromatography (GPC). The polymer was dissolved in 1,2,4-trichlorobenzene at a concentration of 1 mg / mL. The chromatographic conditions were: column temperature 150℃, mobile phase 1,2,4-trichlorobenzene, and flow rate 1 mL / min.

[0076] (3) Metal content: The Al content in the catalyst was determined by ICP-OES.

[0077]

Example 1

[0078] Preparation method of bicerocene catalyst MⅠ / monoclocene catalyst MⅡ supported catalyst:

[0079] First, under N2 protection, take 3g of silica gel (ES70W, porosity 1.66cm). 3 / g, surface area 280-350m² 2 / g, average pore size The average particle size (38 μm) was placed in a reaction flask, and 80 mL of toluene was added for dispersion. 2.1 g of dry methylaluminoxane (MAO) was dissolved in 5 mL of toluene and added to the silica gel dispersion. The mixture was heated to 80 °C and stirred for 1 hour. The mixture was washed three times with toluene and dried under vacuum to obtain a solid powder.

[0080] In the second step, under N2 protection, 80 mL of toluene solvent was added, and stirring and heating were started to bring the temperature to 80 °C. 0.2 g of the dicelocene catalyst MⅠ and 0.016 g of the monocelocene catalyst MⅡ were dissolved in 5 mL of toluene containing the co-catalyst (0.5 g MAO), and then added to a silica gel dispersion loaded with MAO. The mixture was stirred at 80 °C for 2 hours, washed three times with toluene and three times with hexane, and then vacuum dried to obtain a solid powder of the dicelocene catalyst MⅠ / monocene catalyst MⅡ supported catalyst.

[0081]

Example 2

[0082] Preparation method of bicerocene catalyst MⅠ / monoclocene catalyst MⅢ supported catalyst:

[0083] First, under N2 protection, take 3g of silica gel (ES70W, porosity 1.66cm). 3 / g, surface area 280-350m² 2 / g, average pore size The average particle size (38 μm) was placed in a reaction flask, and 80 mL of toluene was added for dispersion. 2.1 g of dry MAO was dissolved in 5 mL of toluene and added to the silica gel dispersion. The mixture was heated to 80 °C and stirred for 1 hour. The mixture was washed three times with toluene and dried under vacuum to obtain a solid powder.

[0084] In the second step, under N2 protection, 80 mL of toluene solvent was added, and stirring and heating were started to bring the temperature to 80 °C. 0.2 g of the di-metallocene catalyst MⅠ and 0.016 g of the mono-metallocene catalyst MⅢ were dissolved in 5 mL of toluene containing the co-catalyst (0.5 g MAO), and then added to a silica gel dispersion loaded with MAO. The mixture was stirred at 80 °C for 2 hours, washed three times with toluene and three times with hexane, and then vacuum dried to obtain a solid powder of the di-metallocene catalyst MⅠ / mono-metallocene catalyst MⅢ supported catalyst.

[0085]

Example 3

[0086] Preparation method of bicerocene catalyst MⅣ / monoclocene catalyst MⅡ supported catalyst:

[0087] First, under N2 protection, take 3g of alumina (porosity 0.45cm³). 3 / g, surface area 150-200m² 2 / g (average particle size 50um) was placed in a reaction flask, and 60mL of xylene was added for dispersion. 2.1g of dry modified methylaluminoxane:isobutylaluminoxane (MMAO) was dissolved in 5mL of dichloromethane and added to the alumina dispersion. The mixture was heated to 80℃ and stirred for 1 hour. The mixture was washed three times with xylene and dried to obtain a solid powder.

[0088] In the second step, under N2 protection, 60 mL of xylene solvent was added, and stirring and heating were started to bring the temperature to 80 °C. 0.3 g of the dicelocene catalyst MⅣ and 0.016 g of the monocelocene catalyst MⅡ were dissolved in 5 mL of dichloromethane containing the co-catalyst (0.5 g MMAO), and then added to an alumina dispersion loaded with MMAO. The mixture was stirred at 80 °C for 2 hours, washed three times with xylene and three times with hexane, and then vacuum dried to obtain a solid powder of the dicelocene catalyst MⅣ / monocene catalyst MⅡ supported catalyst.

[0089]

Example 4

[0090] Preparation method of bicerocene catalyst MⅣ / monoclocene catalyst MⅢ supported catalyst:

[0091] First, under N2 protection, take 3g of anhydrous magnesium dichloride (porosity 0.04cm³). 3 / g, surface area 11m² 2 / g, after grinding for 32 hours, with an average particle size of 5 μm) was placed in a reaction flask, and 60 mL of monochlorobenzene was added for dispersion. 2.1 g of triethylaluminum was dissolved in 5 mL of tetrahydrofuran and added to the magnesium dichloride dispersion. The mixture was heated to 80 °C and stirred for 1 hour. It was washed three times with monochlorobenzene and dried to obtain a solid powder.

[0092] In the second step, under N2 protection, 60 mL of monochlorobenzene solvent was added, and stirring and heating were started to bring the temperature to 80 °C. 0.3 g of the bis(chlorobenzene) catalyst MⅣ and 0.016 g of the mono(chlorobenzene) catalyst MⅢ were dissolved in 5 mL of tetrahydrofuran containing a co-catalyst (0.5 g of triethylaluminum), and then added to a magnesium dichloride dispersion loaded with triethylaluminum. The mixture was stirred at 80 °C for 2 hours, washed three times with monochlorobenzene, and three times with hexane. After vacuum drying, a solid powder of the bis(chlorobenzene) catalyst MⅣ / monocene catalyst MⅢ supported catalyst was obtained.

[0093]

Example 5

[0094] Preparation method of bicerocene catalyst MⅤ / monoclocene catalyst MⅡ supported catalyst:

[0095] First, under N2 protection, take 2.5g of silica gel (ES70W, porosity 1.66cm). 3 / g, surface area 280-350m² 2 / g, average pore size The average particle size (38 μm) was placed in a reaction flask, and 60 mL of toluene was added for dispersion. 1.5 g of MAO was dissolved in 5 mL of toluene and added to the silica gel dispersion. The mixture was heated to 80 °C and stirred for 1 hour. The mixture was washed three times with toluene and dried under vacuum to obtain a solid powder.

[0096] In the second step, under N2 protection, 60 mL of toluene solvent was added, and stirring and heating were started to bring the temperature to 80 °C. 0.3 g of the di-metallocene catalyst MⅤ and 0.015 g of the mono-metallocene catalyst MⅡ were dissolved in 5 mL of toluene containing the co-catalyst (0.5 g MAO), and then added to a silica gel dispersion loaded with MAO. The mixture was stirred at 80 °C for 2 hours, washed three times with toluene and three times with hexane, and then vacuum dried to obtain a solid powder of the di-metallocene catalyst MⅤ / mono-metallocene catalyst MⅡ supported catalyst.

[0097]

Example 6

[0098] Preparation method of bicerocene catalyst MⅤ / monoclocene catalyst MⅢ supported catalyst:

[0099] First, under N2 protection, take 4g of silica gel (ES70W, porosity 1.66cm). 3 / g, surface area 280-350m² 2 / g, average pore size The average particle size (38 μm) was placed in a reaction flask, and 60 mL of toluene was added for dispersion. 1.5 g of MAO was dissolved in 5 mL of toluene and added to the silica gel dispersion. The mixture was heated to 80 °C and stirred for 1 hour. The mixture was washed three times with toluene and dried under vacuum to obtain a solid powder.

[0100] In the second step, under N2 protection, 60 mL of toluene solvent was added, and stirring and heating were started to bring the temperature to 80 °C. 0.2 g of the bis-metallocene catalyst MⅤ and 0.02 g of the mono-metallocene catalyst MⅢ were dissolved in 10 mL of toluene containing the co-catalyst (1.0 g MAO), and then added to a silica gel dispersion loaded with MAO. The mixture was stirred at 80 °C for 2 hours, washed three times with toluene and three times with hexane, and then vacuum dried to obtain a solid powder of the bis-metallocene catalyst MⅤ / mono-metallocene catalyst MⅢ supported catalyst.

[0101] Comparative Example 1

[0102] Preparation method of bicerocene metal catalyst MⅠ supported catalyst:

[0103] First, under N2 protection, take 3g of silica gel (ES70W, porosity 1.66cm). 3 / g, surface area 280-350m² 2 / g, average pore size The average particle size (38 μm) was placed in a reaction flask, and 80 mL of toluene was added for dispersion. 2.1 g of dry MAO was dissolved in 5 mL of toluene and added to the silica gel dispersion. The mixture was heated to 80 °C and stirred for 1 hour. The mixture was washed three times with toluene and dried under vacuum to obtain a solid powder.

[0104] In the second step, under N2 protection, 80 mL of toluene solvent was added, and stirring and heating were started to bring the temperature to 80 °C. 0.2 g of the bis-ceramic catalyst MⅠ was dissolved in 5 mL of co-catalyst (0.5 g MAO), and then added to the MAO-loaded silica dispersion. The mixture was stirred at 80 °C for 2 hours, washed three times with toluene and three times with hexane, and then vacuum dried to obtain a solid powder of the bis-ceramic catalyst MⅠ supported catalyst.

[0105] Comparative Example 2

[0106] Preparation method of monoceramic metal catalyst MⅡ supported catalyst:

[0107] First, under N2 protection, take 3g of silica gel (ES70W, porosity 1.66cm). 3 / g, surface area 280-350m² 2 / g, average pore size The average particle size (38 μm) was placed in a reaction flask, and 80 mL of toluene was added for dispersion. 2.1 g of dry MAO was dissolved in 5 mL of toluene and added to the silica gel dispersion. The mixture was heated to 80 °C and stirred for 1 hour. The mixture was washed three times with toluene and dried under vacuum to obtain a solid powder.

[0108] In the second step, under N2 protection, 80 mL of toluene solvent was added, and stirring and heating were started to bring the temperature to 80 °C. 0.2 g of the monoceramic catalyst MⅡ was dissolved in 5 mL of co-catalyst (0.5 g MAO), and then added to the MAO-loaded silica dispersion. The mixture was stirred at 80 °C for 2 hours, washed three times with toluene and three times with hexane, and then vacuum dried to obtain a solid powder of the monoceramic catalyst MⅡ supported catalyst.

[0109] The catalysts obtained in Example 1 and Comparative Examples 1 and 2 were subjected to ethylene homopolymerization reactions respectively:

[0110] The homopolymerization of ethylene was carried out under anhydrous and oxygen-free conditions at a reaction temperature of 85℃ and an ethylene pressure of 1 MPa. 1 L of n-hexane was added to a 2 L reactor, followed by 2 mL of the co-catalyst methylaluminoxane (MAO) (10 wt% toluene solution), and then 100 mg of catalyst was added. The reaction temperature was raised to 85℃, and ethylene was introduced to a pressure of 1 MPa. The reaction was stirred for 1 h. After the reaction was completed, the ethylene feed valve was closed, the reactor temperature was lowered to 30℃, the ethylene was vented, and the polymer was dried and weighed. The specific results are shown in Table 2 below.

[0111] Table 2

[0112]

[0113] From the above table 2 and Figure 1-3The results show that the catalyst prepared in Example 1 of this invention can prepare polyethylene with a bimodal molecular weight distribution in the homopolymerization reaction of ethylene, while the corresponding catalysts prepared in Comparative Examples 1 and 2 can only prepare polyethylene with a unimodal molecular weight distribution in the homopolymerization reaction of ethylene.

Claims

1. A diclinocero / monocene metal-supported catalyst, characterized in that: The catalyst includes a support and a dicelocene catalyst, a monocelocene catalyst, and a co-catalyst supported on the support. The weight ratio of the support to the total weight of the di- and mono-metallocene catalysts is (2-100):1; The weight ratio of the di-metallocene catalyst to the mono-metallocene catalyst is (1-100):1; The weight ratio of the dimorphocene catalyst to the co-catalyst is 1:(1-80).

2. The supported catalyst according to claim 1, characterized in that: The weight ratio of the support to the total weight of the di- and mono-metallocene catalysts is (2-20):

1. The weight ratio of the di-metallocene catalyst to the mono-metallocene catalyst is (5-50):1; The weight ratio of the dicerocene catalyst to the co-catalyst is 1:(5-50).

3. The supported catalyst according to claim 1 or 2, characterized in that: The carrier is at least one selected from silicon dioxide, alumina, aluminosilicate, inorganic clay, magnesium oxide, and magnesium dichloride; and / or, The dicyclopentadienyl catalyst is at least one of Cp₂M₁X₁₂, IndCpM₂X₂₂, Et(Ind)₂M₃X₃₂, and Ind₂M₄X₄₂, wherein Cp is cyclopentadienyl, Ind is indene, Et is ethylene, M₁, M₂, M₃, and M₄ can be the same or different, and are independently one of Ti, Zr, and Hf, respectively; X₁, X₂, X₃, and X₄ can be the same or different, and are independently one of Cl, Br, and I, respectively; and / or, The monoceramic catalyst is Me2Si(R4CpNR')MX and / or Me5CpM'X', wherein R is one of methyl, ethyl, or propyl; Cp is cyclopentadienyl; R' is one of methyl, ethyl, propyl, isopropyl, or tert-butyl; M is one of Ti, Zr, or Hf; X is one of Cl, Br, or I; M' is one of Ti, Zr, or Hf; and X' is one of Cl, Br, or I; and / or, The cocatalyst is at least one of methylaluminoxane, modified methylaluminoxane, triethylaluminum, ethylaluminoxane, and isobutylaluminoxane.

4. The supported catalyst according to claim 1 or 2, characterized in that: The porosity of the carrier is 0.04–2 cm³. 3 / g, and / or, with a surface area of ​​10–500 m² 2 / g, and / or, average pore size is And / or, with an average particle size of 5–80 μm.

5. A method for preparing a dicyclopentadiene / monocene metal-supported catalyst as described in any one of claims 1 to 4, the method comprising: The di- and mono-metallocene catalysts were loaded onto a support pre-loaded with a catalyst using an impregnation method.

6. The method according to claim 5, characterized in that... The method includes: (1) Under a protective gas atmosphere, a portion of the co-catalyst solution was added to the carrier dispersion and heated to react, thereby obtaining a carrier dispersion loaded with the co-catalyst. (2) Under a protective gas atmosphere, the di-metallocene catalyst and the mono-metallocene catalyst are dissolved in the remaining co-catalyst solution and then added to the carrier dispersion on which the co-catalyst is supported. The mixture is stirred and reacted, and after standing and separating into layers, it is filtered to obtain the supported catalyst.

7. The method according to claim 6, characterized in that: In step (1): Based on the molar amount of aluminum in the co-catalyst, the concentration of the co-catalyst is 0.1–10 mmol / ml, preferably 0.1–5 mmol / ml; and / or, The concentration of the carrier dispersion is 0.01–0.1 g / ml, preferably 0.01–0.05 g / ml; and / or, The co-catalyst constitutes 50% to 85% of the total weight of the co-catalyst, preferably 70% to 85%; and / or, The weight ratio of the carrier to the total cocatalyst is (1-100):1, preferably (1-10):

1.

8. The preparation method according to claim 6, characterized in that: In step (2): Based on the molar amount of aluminum in the co-catalyst, the concentration of the remaining co-catalyst is 0.1–3 mmol / ml, preferably 0.1–1 mmol / ml; and / or, The weight ratio of the dicelocene catalyst to the monocelocene catalyst is (1-100):1, preferably (5-50):1; and / or, The weight ratio of the dicelocene catalyst to the total co-catalyst is 1:(1-80), preferably 1:(5-50).

9. The method according to claim 6, characterized in that: In step (1): The solvent for the partial catalyst solution is at least one selected from toluene, dichloromethane, trichloromethane, and tetrahydrofuran; and / or, The solvent of the carrier dispersion is at least one selected from benzene, toluene, xylene, monochlorobenzene, dichlorobenzene, and trichlorobenzene; and / or, The heating reaction is carried out at a temperature of 50–100°C and / or for a time of 1–3 hours.

10. The method according to claim 6, characterized in that: In step (2): The solvent for the remaining co-catalyst solution is at least one selected from toluene, dichloromethane, trichloromethane, and tetrahydrofuran; and / or, The reaction temperature of the stirring reaction is 60–80°C, and / or the reaction time is 2–4 h.

11. The application of a bis(c)- or monoc)-metal supported catalyst as described in any one of claims 1 to 4, or a bis(c)- or monoc)-metal supported catalyst prepared by the method as described in any one of claims 5 to 10, in catalyzing olefin polymerization, preferably wherein the olefin polymerization is ethylene homopolymerization.

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