Silica gel supported nickel-vanadium bimetallic catalyst, and preparation method and application thereof

Abstract

The application discloses a silica gel supported nickel-vanadium bimetallic catalyst and a preparation method and application thereof, and relates to a preparation method of a silica gel supported nickel-vanadium bimetallic catalyst, which comprises the following steps: impregnating and stirring silica gel and a vanadium source in a first solvent to obtain impregnated silica gel, performing heat treatment on the impregnated silica gel to obtain a solid powder, and loading a nickel metal complex shown in formula 2 on the solid powder to obtain the catalyst. The application improves the reaction activity of the nickel metal complex, and can be used for producing wide distribution / bimodal polyolefin plastomer (POP), so that high molecular weight end insertion is increased and low molecular weight end insertion is reduced under the premise of ensuring wide molecular weight distribution, and the mechanical properties of the polymer are improved.

Description

Technical Field

[0001] This invention relates to the field of polymer catalyst technology, specifically to a silica-supported nickel-vanadium bimetallic catalyst, its preparation method, and its application. Background Technology

[0002] Bimodal / widely distributed polyethylene, due to the presence of two peaks in its molecular weight distribution curve and its wide distribution range, can achieve both excellent mechanical properties and good processing performance through the combination of high molecular weight components and low molecular weight components.

[0003] Currently, there are three main industrial processes for producing bimodal / wide distribution polyethylene:

[0004] (1) Parallel reactor process: polymers with different molecular weight distributions are produced by two reactors and blended in the molten state; (2) Series reactor process: polymers with different molecular weights are prepared in different reactors by changing polymerization conditions; (3) Single reactor process: catalysts with multiple active sites, single catalysts with multiple supports, and mixed catalysts are used.

[0005] Both series and parallel reactor processes have high production costs and poor product stability. Single-reactor processes have low production costs and good product stability, but the performance of the resulting polyethylene product is inextricably linked to the catalyst. Currently disclosed polyethylene catalysts mainly include Ziegler-Natta catalysts, chromium-based catalysts, and metallocene catalysts. However, when applied to polyethylene production, these catalysts all suffer from the inability to simultaneously address both product molecular weight distribution and catalytic activity. Specifically, catalysts suitable for producing polyethylene with a wide molecular weight distribution tend to have relatively low catalytic activity; conversely, catalysts with high catalytic activity produce products with a relatively narrow molecular weight distribution, making them unsuitable for industrial production. Summary of the Invention

[0006] Therefore, the technical problem to be solved by the present invention is how to improve the catalyst activity while expanding the molecular weight distribution width of the produced polyethylene products, thereby providing a silica-supported nickel-vanadium bimetallic catalyst, its preparation method and application, to achieve the above objective.

[0007] A silica-supported nickel-vanadium bimetallic catalyst has the structure shown in Formula 1:

[0008] Formula 1:

[0009] Among them, X, Y, R 1 –R 4 Each is independently selected from hydrogen, halogen, or any of the following groups: C1-6 Alkyl, C 1-6 Alkoxy, C 3-10 cycloalkyl, C 3-10 Cycloalkyloxy, C 6-14 Aryl, C 6-14 Aryloxy group.

[0010] R 1 –R 4 Each is independently selected from hydrogen, fluorine, chlorine, bromine, and C. 1-6 Alkyl, C 3-10 cycloalkyl or C 6-14 Aryl; or, X, Y, R 1 –R 4 Each is independently selected from any one of hydrogen, methyl, isopropyl, tert-butyl, fluorine, chlorine, methoxy, trifluoromethyl, or cyclohexyl.

[0011] A method for preparing a silica-supported nickel-vanadium bimetallic catalyst, comprising:

[0012] Silica gel and vanadium source are impregnated and stirred in a first solvent to obtain impregnated silica gel. The impregnated silica gel is then heat-treated to obtain a solid powder. The solid powder is then loaded with a nickel metal complex as shown in Formula 2 to obtain a catalyst.

[0013] Formula 2: Among them, X, Y, R 1 –R 4 The definition is the same as that in claim 1 or 2.

[0014] The amount of vanadium source added is 0.1-1 wt% of the total weight of the silica gel, based on the loading of metallic vanadium.

[0015] And / or, the amount of the nickel metal complex added, based on the loading of metallic nickel, is 0.1-1 wt% of the amount of silica gel.

[0016] The first solvent is water or ethanol;

[0017] And / or, the vanadium source is a vanadium-containing substance soluble in the first solvent, preferably, the vanadium source is one or more of ammonium metavanadate, vanadium nitrate, vanadium acetate, vanadium oxalate, vanadium phosphate, vanadium sulfate, vanadium oxalate, vanadium acetylacetonate, vanadium diacetylacetonate, vanadium trichlorooxide, and vanadium tripropanol oxide.

[0018] And / or, the impregnation and stirring time is 1-12 hours, preferably 3-6 hours;

[0019] And / or, the temperature of the heat treatment is 500-1000℃, preferably 600-800℃;

[0020] And / or, the heat treatment time is 6-12 hours.

[0021] And / or, the heat treatment is followed by cooling in an inert atmosphere;

[0022] And / or, the process of loading the nickel metal complex onto the solid powder is as follows: under an inert atmosphere, the solid powder is mixed with the second solvent and the nickel metal complex, stirred, and the second solvent is evaporated to obtain the catalyst.

[0023] The inert atmosphere is a nitrogen atmosphere;

[0024] And / or, the processing temperature for stirring is 35-60℃, and the processing time is 2-10h;

[0025] And / or, the evaporation temperature is 60-95℃;

[0026] And / or, the second solvent includes one or more of n-hexane, n-heptane, cyclohexane, n-pentane, methylcyclopentane, and methylcyclohexane.

[0027] The preparation method of the nickel metal complex includes:

[0028] The acenaphthyl α-diimine ligand with the structure shown in Formula 3 was obtained by mixing and reacting the acenaphthyl α-diimine ligand with a nickel source containing nickel dibromide to obtain the nickel metal complex shown in Formula 2; the preparation process of the acenaphthyl α-diimine ligand shown in Formula 3 is as follows: the compounds shown in Formula 4 and Formula 5 are subjected to a synthetic reaction to obtain the acenaphthyl α-diimine ligand shown in Formula 3;

[0029] Formula 3:

[0030] Formula 4:

[0031] Formula 5:

[0032] The solvent used in the synthesis reaction of the compounds shown in Formulas 4 and 5 is C. 1-4 Alcohols, preferably including one or two of anhydrous methanol and anhydrous ethanol;

[0033] And / or, the solvent used in the step of reacting the acenaphthene α-diimine ligand with a nickel source containing nickel dibromide is one or more of tetrahydrofuran, anhydrous diethyl ether, pentane, cyclopentane, n-hexane, cyclohexane, heptane, methylcyclohexane, toluene, xylene, chlorobenzene, o-dichlorobenzene, o-xylene, and dichloromethane.

[0034] This invention also discloses the application of the above-mentioned silica-supported nickel-vanadium bimetallic catalyst in the ethylene polymerization reaction.

[0035] Alkyl aluminum is also added to the ethylene polymerization reaction, wherein the molar ratio of the alkyl aluminum to nickel in the silica-supported nickel-vanadium bimetallic catalyst is 5-200:1; preferably, the molar ratio of the alkyl aluminum to nickel in the silica-supported nickel-vanadium bimetallic catalyst is 10-100:1, and / or, the alkyl aluminum is one or more selected from trimethylaluminum, triethylaluminum, triisobutylaluminum, diethylaluminum chloride, trioctylaluminum, methylaluminoxane, modified methylaluminoxane, and ethylaluminoxane;

[0036] And / or, the ethylene polymerization process is as follows: ethylene is mixed with a third solvent, comonomer, and alkyl aluminum, and then a silica gel-supported nickel-vanadium bimetallic catalyst is added for polymerization; preferably, the ethylene and / or the third solvent are dehydrated and deoxygenated before being mixed with the comonomer, and / or, the polymerization conditions are 60-150℃, 0.5-8MPa, and 10-240min, and / or, the third solvent includes one or more of n-hexane, n-heptane, methylcyclohexane, toluene, or cyclohexane, and / or, the comonomer includes one or more of 1-butene, 1-hexene, or 1-octene.

[0037] The technical solution of this invention has the following advantages:

[0038] 1. The present invention provides a silica-supported nickel-vanadium bimetallic catalyst, which, through the synergistic interaction of silica, vanadium and nickel metal complexes, not only achieves the goal of producing ethylene / α-olefin copolymers with a wider molecular weight distribution, but also effectively improves catalyst activity, thus achieving the goal of balancing product molecular weight distribution and catalytic activity.

[0039] 2. The catalyst of this invention has good stability, high polymerization activity, and high economic added value, and has a very good prospect for industrialization.

[0040] 3. In the application of this invention, the molecular weight and molecular weight distribution can be easily adjusted by changing the amount of co-catalyst, polymerization temperature, and molecular weight regulator, resulting in high production flexibility and the ability to produce multiple batches of products. Attached Figure Description

[0041] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0042] Figure 1 This is a synthetic route diagram of the silica-supported nickel-vanadium bimetallic catalyst in this invention. Detailed Implementation

[0043] The following embodiments are provided to better understand the present invention and are not limited to the preferred embodiments described. They do not constitute a limitation on the content and scope of protection of the present invention. Any product that is the same as or similar to the present invention, derived by any person under the guidance of the present invention or by combining the features of the present invention with other prior art, falls within the protection scope of the present invention.

[0044] For experiments not specifically described in the examples, the procedures or conditions should be followed according to the conventional experimental procedures described in the literature in this field. Reagents or instruments whose manufacturers are not specified are all commercially available conventional reagent products.

[0045] Example 1

[0046] A silica-supported nickel-vanadium bimetallic catalyst, the synthetic route of which is as follows: Figure 1 As shown, the specific preparation process is as follows:

[0047] (1) Obtain the raw materials for the structures shown in Formula 4 and Formula 5;

[0048] The raw materials for the structure shown in Equation 4 are: The raw materials for the structure shown in Formula 4 can be synthesized or purchased. In this embodiment, the raw materials for the structure shown in Formula 4 were purchased from Anhui Dunmao New Material Technology Co., Ltd.

[0049] The raw materials for the structure shown in Formula 5 are 2,6-dimethylaniline and aniline.

[0050] (2) Prepare the acenaphthene α-diimine ligand L1 with the structure shown in Formula 3;

[0051] The compound shown in Formula 3 was prepared according to the method described in Organometallics, 2016, 11, 1794-1801. The specific procedure is as follows:

[0052] The compound shown in Formula 4 was reacted with 1 equiv. of 2,6-dimethylaniline and 1 equiv. of aniline shown in Formula 5 to synthesize the corresponding acenaphthene α-diimine ligand L1 with the structure shown in Formula 3. The synthesis process was as follows: 2.5 mmol of the compound shown in Formula 4 and 5.5 mmol of the compound shown in Formula 5 were added to a round-bottom flask containing 25 ml of methanol, and the mixture was reacted overnight at room temperature under the catalysis of 0.1 ml of formic acid. The mixture was filtered to obtain a yellow solid, which was then washed with hot methanol to obtain ligand L1.

[0053] Ligand L1: N,N-((2,6-diisopropylphenyl)imino)-4,7-dimethylacenaphthene, yield 1.02 g, with a yield of 60%.

[0054] Rf = 0.50 (petroleum ether / dichloromethane, 1:2), its NMR data are:

[0055] 1 H NMR(CDCl3,400MHz): δ7.55(s,2H,aryl-H),7.34-7.16(m,6H,aryl-H),6.48(s,2H, aryl-H),3.19-2.87(dt,4H,CHMe2),2.3(s,6H,aryl-Me),1.4-0.8(dd,24H,CHMe2);

[0056] 13 C NMR(100MHz, CDCl3): δ161.48(N=C),147.66,138.25,138.09,135.56,131.32,1 29.46,127.29,124.48,124.33,123.44,28.66,23.53,23.24,22.46(aryl-Me).

[0057] Its mass spectrometry data are: [M+H] + The calculated value is 529.3583, and the experimental value is 529.3572.

[0058] Elemental analysis data are as follows: calculated values ​​are C, 86.31; H, 8.39; N, 5.30; experimental values ​​are C, 86.02; H, 8.19; N, 5.36.

[0059] (3) Prepare the nickel metal complex C1 shown in Formula 2;

[0060] The obtained ligand L1 (0.49 mmol) was added together with 1 equiv. of (DME)NiBr2 (0.49 mmol) into a solvent storage bottle containing 10 mL of dichloromethane. The reaction was carried out overnight at room temperature, dried under vacuum, washed four times with 20 mL of diethyl ether, and then dried under vacuum to obtain the nickel metal complex C1 with the structure shown in Formula 2.

[0061] C1:(4,7-diMeN^N)NiBr2, yield was 0.275 g, with a yield of 75%.

[0062] Its mass spectrometry data is: [M-Br]+ experimental value is 665.0144.

[0063] Elemental analysis data are as follows: calculated values ​​are C, 61.08; H, 5.93; N, 3.75; experimental values ​​are C, 61.28; H, 5.71; N, 3.46.

[0064] (4) Preparation of silica-supported nickel-vanadium bimetallic catalyst;

[0065] Weigh 10g of Grace Davison 955 silica gel and immerse it in an ammonium metavanadate aqueous solution at 35°C with stirring for 3 hours. The amount of ammonium metavanadate used is 0.15wt% (34.5mg) of the silica gel mass, based on the vanadium loading. Then, evaporate the aqueous solution at 120°C and dry to obtain the impregnated silica gel.

[0066] In an air atmosphere, the impregnated silica gel was calcined at 600°C for 8 hours in a fluidized bed. Then, the heating was turned off, the atmosphere was switched to nitrogen, and the mixture was cooled to room temperature to obtain a solid powder.

[0067] Under the protection of high-purity nitrogen, 5g of solid powder was first transferred to a container, and 150mL of purified n-hexane was added as a solvent using a syringe. 153.0mg of nickel metal complex C1, which was 0.27wt% of the solid powder mass based on the nickel loading, was then added. The temperature was adjusted to 45℃ and stirred continuously at a constant temperature for 5h. Then the temperature was raised to 80℃ while the nitrogen flow rate was increased. After the n-hexane was completely evaporated, a silica gel-supported nickel-vanadium bimetallic catalyst, denoted as Cat1, was obtained.

[0068] Example 2

[0069] A silica-supported nickel-vanadium bimetallic catalyst, the synthetic route of which is as follows: Figure 1 As shown, the specific preparation process is as follows:

[0070] (1) Obtain the raw materials for the structures shown in Formula 4 and Formula 5;

[0071] The raw materials for the structure shown in Equation 4 are: The raw materials for the structure shown in Formula 4 can be synthesized or purchased. In this embodiment, the raw materials for the structure shown in Formula 4 were purchased from Anhui Dunmao New Material Technology Co., Ltd.

[0072] The raw materials for the structure shown in Formula 5 are 2,6-diisopropylaniline and aniline.

[0073] (2) Prepare the acenaphthene α-diimine ligand L2 with the structure shown in Formula 3;

[0074] The compound shown in Formula 3 was prepared according to the method described in Organometallics, 2016, 11, 1794-1801. The specific procedure is as follows:

[0075] The compound shown in Formula 4 was reacted with 1 equiv. of 2,6-diisopropylaniline and 1 equiv. of aniline shown in Formula 5 to synthesize the corresponding acenaphthene α-diimine ligand L2 with the structure shown in Formula 3. The synthesis process was as follows: 2.5 mmol of the compound shown in Formula 4 and 5.5 mmol of the compound shown in Formula 5 were added to a round-bottom flask containing 25 ml of methanol, and the mixture was reacted overnight at room temperature under the catalysis of 0.1 ml of formic acid. The mixture was filtered to obtain a yellow solid, which was then washed with methanol to obtain ligand L2.

[0076] Ligand L2: N,N-((2,6-diisopropylphenyl)imino)-5-methoxyacenaphthene, yield 0.86 g, with a yield of 65%.

[0077] Rf = 0.40 (ethyl acetate / petroleum ether, 1:20), its NMR data are:

[0078] 1H NMR (CDCl3, 400MHz): δ8.09 (d, J=8.3Hz, 1H, aryl-H), 7.44-7.23 (m, 6H, aryl-H), 7.23 (s, 1H, aryl-H), 6 .77-6.52(m,3H,aryl-H),3.97(s,3H,aryl-OMe),3.20-2.73(m,4H,CHMe2),1.38-0.84(m,24H,CHMe2);

[0079] 13 C NMR (100MHz, CDCl3): δ161.80(N=C), 160.40(N=C), 157.54(O-Caryl), 135.92, 126.97, 125.16, 124.37, 124. 31,124.12,124.03,123.54,123.50,123.15,105.79,55.96(OMe),28.70,28.65,23.63,23.54,23.31,23.25.

[0080] Its mass spectrometry data are: [M+H]+ calculated value 531.3375, experimental value 531.3368.

[0081] Elemental analysis data are as follows: calculated values ​​are C, 83.73; H, 7.98; N, 5.28; experimental values ​​are C, 83.45; H, 7.78; N, 5.31.

[0082] (3) Prepare the nickel metal complex C2 shown in Formula 2;

[0083] The obtained ligand L2 (0.49 mmol) and 1 equiv. of (DME)NiBr2 (0.49 mmol) were added to a solvent storage bottle containing 10 mL of dichloromethane. The reaction was carried out overnight at room temperature, dried under vacuum, washed four times with 20 mL of diethyl ether, and then dried under vacuum to obtain the nickel metal complex C2 with the structure shown in Formula 2.

[0084] C2:(5-OMeN^N)NiBr2, yield was 0.307 g, with a yield of 80%.

[0085] Its mass spectrometry data is: [M-Br]+ experimental value is 667.0510.

[0086] Elemental analysis data are as follows: calculated values ​​are C, 59.31; H, 5.65; N, 3.74; experimental values ​​are C, 59.53; H, 5.92; N, 3.48.

[0087] (4) Preparation of silica-supported nickel-vanadium bimetallic catalyst

[0088] Weigh 10g of Grace Davison 945 silica gel and impregnate and stir the silica gel in a vanadium nitrate aqueous solution at 40℃ for 4h. The amount of vanadium nitrate used is 0.3wt% (212.6mg) of the silica gel mass based on the vanadium loading. Then, evaporate the aqueous solution at 115℃ and dry to obtain the impregnated silica gel.

[0089] In an air atmosphere, the impregnated silica gel was calcined at 700°C for 9 hours in a fluidized bed. Then, the heating was turned off, the atmosphere was switched to nitrogen, and the mixture was cooled to room temperature to obtain a solid powder.

[0090] Under the protection of high-purity nitrogen, 5g of solid powder was first transferred to a container, and 150mL of purified n-hexane was added as a solvent using a syringe. 170.5mg of nickel metal complex C2, which is 0.3wt% of the mass of the silica gel-supported vanadium catalyst, was then added. The temperature was adjusted to 50℃ and stirred continuously at a constant temperature for 6h. Then the temperature was raised to 85℃ while increasing the nitrogen flow rate. After the n-hexane was completely evaporated, the silica gel-supported nickel-vanadium bimetallic catalyst, denoted as Cat2, was obtained.

[0091] Example 3

[0092] A silica-supported nickel-vanadium bimetallic catalyst, the synthetic route of which is as follows: Figure 1 As shown, the specific preparation process is as follows:

[0093] (1) Obtain the raw materials for the structures shown in Formula 4 and Formula 5;

[0094] The raw materials for the structure shown in Equation 4 are: The raw materials for the structure shown in Formula 4 can be synthesized or purchased. In this embodiment, the raw materials for the structure shown in Formula 4 were purchased from Anhui Dunmao New Material Technology Co., Ltd.

[0095] The raw materials for the structure shown in Formula 5 are 2,6-diisopropylaniline and aniline.

[0096] (2) Prepare the acenaphthene α-diimine ligand L3 with the structure shown in Formula 3;

[0097] The compound shown in Formula 3 was prepared according to the method described in Organometallics, 2016, 11, 1794-1801. The specific procedure is as follows:

[0098] The compound shown in Formula 4 was reacted with 1 equiv. of 2,6-diisopropylaniline and 1 equiv. of aniline shown in Formula 5 to synthesize the corresponding acenaphthene α-diimine ligand L3 with the structure shown in Formula 3. The synthesis process was as follows: the starting material was added to a round-bottom flask containing 25 ml of methanol, and the reaction was carried out overnight at room temperature under the catalysis of 0.1 ml of formic acid. The mixture was filtered to obtain a yellow solid, which was then washed with hot methanol to obtain ligand L3.

[0099] Ligand L3: N,N-((2,6-diisopropylphenyl)imino)-5,6-dimethylacenaphthene, yield 0.84 g, with a yield of 60%.

[0100] Rf = 0.30 (ethyl acetate / petroleum ether, 1:20), its NMR data are:

[0101] 1 H NMR (CDCl3, 400MHz): δ7.21 (dt, J=18.7, 8.7Hz, 6H, aryl-H), 6.58 (q, J=8.2Hz, aryl- H),3.9(s,6H,aryl-OMe),2.98(dt,J=13.6,6.8Hz,4H,CHMe2),1.11(dd,24H,CHMe2);

[0102] 13 C NMR (100MHz, CDCl3): δ160.77 (N=C), 159.07 (O-Caryl), 147.88, 145.53, 135.82, 125.8 0,124.37,123.97,123.43,122.24,114.66,106.52,56.33(OMe),28.60,23.61,23.29.

[0103] Its mass spectrometry data are: [M+H] +The calculated value is 561.3481, and the experimental value is 561.3463.

[0104] Elemental analysis data are as follows: calculated values ​​are C, 81.39; H, 7.91; N, 5.00; experimental values ​​are C, 81.08; H, 7.66; N, 4.96.

[0105] (3) Prepare the nickel metal complex C3 shown in Formula 2;

[0106] The obtained ligand L3 (0.49 mmol) was added together with 1 equiv. of (DME)NiBr2 (0.49 mmol) into a solvent storage bottle containing 10 mL of dichloromethane. The reaction was carried out overnight at room temperature, dried under vacuum, washed four times with 20 mL of diethyl ether, and then dried under vacuum to obtain the nickel metal complex C3 with the structure shown in Formula 2.

[0107] C3:(5,6-diOMeN^N)NiBr2, yield was 0.326 g, with a yield of 85%.

[0108] Its mass spectrometry data is: [M-Br]+ experimental value is 697.0929.

[0109] Elemental analysis data are as follows: calculated values ​​are C, 58.57; H, 5.69; N, 3.59; experimental values ​​are C, 58.75; H, 5.73; N, 3.47.

[0110] (4) Preparation of silica-supported nickel-vanadium bimetallic catalyst

[0111] Weigh 10g of PQ CS-2133 silica gel and impregnate and stir it in an aqueous solution of vanadium oxalate at 45℃ for 5h. The amount of vanadium oxalate used is 0.5wt% (152.1mg) of the silica gel mass based on the vanadium loading. Then, evaporate the aqueous solution at 115℃ and dry to obtain the impregnated silica gel.

[0112] In an air atmosphere, the impregnated silica gel was calcined at 800°C for 6 hours in a fluidized bed. Then, the heating was turned off, the atmosphere was switched to nitrogen, and the mixture was cooled to room temperature to obtain a solid powder.

[0113] Under high-purity nitrogen protection, 5g of solid powder was first transferred to a container. 150mL of purified n-hexane was added as a solvent using a syringe, followed by 0.45wt% (267.2mg) of nickel metal complex C3 (based on the nickel loading of the solid powder). The temperature was adjusted to 60℃ and continuously stirred at this temperature for 3 hours. Then, the temperature was raised to 90℃ while simultaneously increasing the nitrogen flow rate. After the n-hexane was completely evaporated, the solid powder obtained was the silica gel-supported nickel-vanadium bimetallic catalyst, denoted as Cat3.

[0114] Example 4

[0115] A silica-supported nickel-vanadium bimetallic catalyst, the synthetic route of which is as follows: Figure 1 As shown, the specific preparation process is as follows:

[0116] (1) Obtain the raw materials for the structures shown in Formula 4 and Formula 5;

[0117] The raw materials for the structure shown in Equation 4 are: The raw materials for the structure shown in Formula 4 can be synthesized or purchased. In this embodiment, the raw materials for the structure shown in Formula 4 were purchased from Anhui Dunmao New Material Technology Co., Ltd.

[0118] The raw materials for the structure shown in Formula 5 are 2,6-diisopropylaniline and aniline.

[0119] (2) Prepare the acenaphthene α-diimine ligand L4 with the structure shown in Formula 3;

[0120] The compound shown in Formula 3 was prepared according to the method described in Organometallics, 2016, 11, 1794-1801. The specific procedure is as follows:

[0121] The compound shown in Formula 4 was reacted with 1 equiv. of 2,6-diisopropylaniline and 1 equiv. of aniline shown in Formula 5 to synthesize the corresponding acenaphthene α-diimine ligand L4 with the structure shown in Formula 3. The synthesis process was as follows: the starting material was added to a round-bottom flask containing 25 ml of methanol, and the reaction was carried out overnight at room temperature under the catalysis of 0.1 ml of formic acid. The mixture was filtered to obtain a yellow solid, which was then washed with hot methanol to obtain ligand L4.

[0122] Ligand L4: N,N-((2,6-diisopropylphenyl)imino)-3-methoxyacenaphthene, yield 0.86 g, with a yield of 65%.

[0123] Rf = 0.30 (ethyl acetate / petroleum ether, 1:20), its NMR data are:

[0124] 1 H NMR (CDCl3, 400MHz): δ7.93 (d, J=8.9Hz, 1H, aryl-H), 7.79 (d, J=8.2Hz, aryl-H), 7.23 (s, 1H, aryl-H), 7.05-7.23 (m, 6H, aryl-H), 7.06 (s, 1H, a ryl-H),6.57(s,1H,aryl-H),4.19,3.29(s,3H,aryl-OMe),2.96(td,4H,CHMe2),1.21(d,J=6.8Hz,12H,CHMe2),0.97(d,J=12.1Hz,12H,CHMe2);

[0125] 13 C NMR (100MHz, CDCl3): δ161.70 (N=C), 160.20 (N=C), 158.49 (OC aryl ), 136.87, 125.97, 124.98, 124.37, 124.35, 124.12, 124.13, 123.57, 123.50, 123.16, 105.79, 56.56 (OMe), 28.70, 28.65, 23.63, 23.55, 23.33, 23.27. Its mass spectrometry data are: [M+H] + The calculated value is 531.3375, and the experimental value is 531.3385.

[0126] Elemental analysis data are as follows: calculated values ​​are C, 83.73; H, 7.98; N, 5.28; experimental values ​​are C, 83.51; H, 7.93; N, 5.37.

[0127] (3) Prepare the nickel metal complex C4 shown in Formula 2;

[0128] The obtained ligand L4 (0.49 mmol) was added together with 1 equiv. of (DME)NiBr2 (0.49 mmol) into a solvent storage bottle containing 10 mL of dichloromethane. The reaction was carried out overnight at room temperature, dried under vacuum, washed four times with 20 mL of diethyl ether, and then dried under vacuum to obtain the nickel metal complex C4 with the structure shown in Formula 2.

[0129] C4:(3-OMeN^N)NiBr2, yield was 0.338 g, with a yield of 88%.

[0130] Its mass spectrometry data is: [M-Br]+ experimental value is 667.0696.

[0131] Elemental analysis data are as follows: calculated values ​​are C, 59.31; H, 5.65; N, 3.74; experimental values ​​are C, 59.45; H, 5.81; N, 3.56.

[0132] (4) Preparation of silica-supported nickel-vanadium bimetallic catalyst;

[0133] Weigh 10g of Grace Davison 955 silica gel and impregnate and stir the silica gel in a vanadium nitrate aqueous solution at 40℃ for 6h. The amount of vanadium nitrate used is 0.2wt% (141.7mg) of the silica gel mass based on the vanadium loading. Then, evaporate the aqueous solution at 115℃ and dry to obtain the impregnated silica gel.

[0134] In an air atmosphere, the impregnated silica gel was calcined at 600°C for 8 hours in a fluidized bed. Then, the heating was turned off, the atmosphere was switched to nitrogen, and the mixture was cooled to room temperature to obtain a solid powder.

[0135] Under high-purity nitrogen protection, 5g of solid powder was first transferred to a container. 150mL of purified n-hexane was added as a solvent using a syringe, followed by 0.25wt% (142.1mg) of nickel metal complex C4 (based on the nickel loading, the mass of the solid powder). The temperature was adjusted to 40℃ and continuously stirred at this temperature for 5 hours. Then, the temperature was raised to 75℃ while simultaneously increasing the nitrogen flow rate. After the n-hexane was completely evaporated, the solid powder obtained was the silica gel-supported nickel-vanadium bimetallic catalyst, denoted as Cat4.

[0136] Example 5

[0137] The difference from Example 2 is that step (4) is different. The specific process for preparing the silica-supported nickel-vanadium bimetallic catalyst is as follows:

[0138] Weigh 10g of PQ CS-2040 silica gel and impregnate and stir it in an ammonium metavanadate aqueous solution at 30℃ for 5h. The amount of ammonium metavanadate is 0.35wt% (80.4mg) of the silica gel mass based on the vanadium loading. Then evaporate the aqueous solution at 115℃ and dry to obtain the impregnated silica gel.

[0139] In an air atmosphere, the impregnated silica gel was calcined at 650°C for 12 hours in a fluidized bed. Then the heating was turned off, the atmosphere was switched to nitrogen, and the mixture was cooled to room temperature to obtain a solid powder.

[0140] Under high-purity nitrogen protection, 5g of solid powder was first transferred to a container. 150mL of purified n-hexane was added as a solvent using a syringe, followed by 0.6wt% (340.9mg) of nickel metal complex C2 (based on the nickel loading of the solid powder). The temperature was adjusted to 40℃ and continuously stirred at this temperature for 5 hours. Then, the temperature was raised to 70℃ while simultaneously increasing the nitrogen flow rate. After the n-hexane was completely evaporated, the solid powder obtained was the silica gel-supported nickel-vanadium bimetallic catalyst, denoted as Cat5.

[0141] Example 6

[0142] The difference from Example 3 is that step (4) is different. The specific process for preparing the silica-supported nickel-vanadium bimetallic catalyst is as follows:

[0143] Weigh 10g of PQ CS-2040 silica gel and immerse it in an ammonium metavanadate aqueous solution at 35℃ with stirring for 3 hours. The amount of ammonium metavanadate used, based on the vanadium loading, is 0.27wt% of the silica gel mass.

[0144] (62mg), then evaporate the aqueous solution at 120℃ and dry to obtain impregnated silica gel;

[0145] In an air atmosphere, the impregnated silica gel was calcined at 900°C for 6 hours in a fluidized bed. Then, the heating was turned off, the atmosphere was switched to nitrogen, and the mixture was cooled to room temperature to obtain a solid powder.

[0146] Under high-purity nitrogen protection, 5g of solid powder was first transferred to a container. 150mL of purified n-hexane was added as a solvent using a syringe. Then, 0.6wt% (356.3mg) of nickel metal complex C3 (based on the nickel loading) of the solid powder was added. The temperature was adjusted to 40℃ and continuously stirred at this temperature for 5 hours. The temperature was then raised to 75℃ while simultaneously increasing the nitrogen flow rate. After the n-hexane was completely evaporated, the solid powder obtained was the silica gel-supported nickel-vanadium bimetallic catalyst, denoted as Cat6.

[0147] Example 7

[0148] The difference from Example 6 is that step (4) is different. The specific process for preparing the silica-supported nickel-vanadium bimetallic catalyst is as follows:

[0149] Weigh 10g of PQ CS-2040 silica gel and immerse it in an ammonium metavanadate aqueous solution at 35℃ with stirring for 3 hours. The amount of ammonium metavanadate used, based on the vanadium loading, is 0.95wt% of the silica gel mass.

[0150] (218mg), then evaporate the aqueous solution at 120℃ and dry to obtain impregnated silica gel;

[0151] In an air atmosphere, the impregnated silica gel was calcined at 900°C for 6 hours in a fluidized bed. Then, the heating was turned off, the atmosphere was switched to nitrogen, and the mixture was cooled to room temperature to obtain a solid powder.

[0152] Under high-purity nitrogen protection, 5g of solid powder was first transferred to a container. 150mL of purified n-hexane was added as a solvent using a syringe. Then, 0.9wt% (534.5mg) of nickel metal complex C3 (based on the nickel loading) of the solid powder was added. The temperature was adjusted to 40℃ and stirred continuously at this temperature for 5 hours. The temperature was then raised to 75℃ while simultaneously increasing the nitrogen flow rate. After the n-hexane was completely evaporated, the solid powder obtained was the silica gel-supported nickel-vanadium bimetallic catalyst, denoted as Cat7.

[0153] Example 8

[0154] The catalytic application of the silica gel-supported nickel-vanadium bimetallic catalyst Cat1 in the ethylene polymerization reaction is as follows:

[0155] A 500ml reactor was heated to 130℃ and evacuated for 2 hours, during which nitrogen was purged three times. Then, ethylene was introduced twice under vacuum. After cooling to room temperature, 150ml of dehydrated and deoxygenated n-heptane and 50ml of 1-hexene were added. When the reactor temperature stabilized at 90℃, 0.16mL of a 1.1mol / L triisobutylaluminum n-hexane solution and 200mg of catalyst Cat1 were added according to an Al / Cr ratio of 30. The mixture was stirred, and 1MPa of ethylene was introduced to initiate the polymerization reaction. After 60 minutes of reaction, the ethylene inlet valve was closed, and the reactor was rapidly cooled using a low-temperature circulating water bath. The pressure was slowly released, and the product (POP) was unloaded. After drying and weighing, the following results were obtained:

[0156] Polymerization activity = 2200 kg POP (mol Ni) -1 h -1 POP has a melting point of 95℃ and a weight-average molecular weight Mw = 12.6 * 10⁻⁶. 4 The molecular weight distribution index (PDI) was 16.5 g / mol. HT 13C-NMR characterization revealed an insertion rate of 16.98% for 1-hexene.

[0157] Example 9

[0158] The catalytic application of the silica gel-supported nickel-vanadium bimetallic catalyst Cat2 in the ethylene polymerization reaction is as follows:

[0159] A 500ml reactor was heated to 120℃ and evacuated for 3 hours, during which nitrogen was purged three times. Then, ethylene was introduced twice under vacuum. After cooling to room temperature, 140ml of dehydrated and deoxygenated n-heptane and 60ml of 1-octene were added. When the reactor temperature stabilized at 100℃, 0.09mL of a 1.1mol / L triisobutylaluminum n-hexane solution and 200mg of catalyst Cat2 were added according to an Al / Cr ratio of 15. The mixture was stirred, and ethylene was introduced at 1.5MPa for polymerization. After 60 minutes of reaction, the ethylene inlet valve was closed, and the reactor was rapidly cooled using a low-temperature circulating water bath. The pressure was slowly released, and the product, polyethylene, was discharged. After drying and weighing, analysis revealed the following:

[0160] Polymerization activity = 1900 kg POP (mol Ni) -1 h -1 POP melting point = 89℃, weight-average molecular weight Mw = 8.1 * 10 4 The molecular weight distribution index (PDI) was 12.2 g / mol. HT 13C-NMR characterization revealed an insertion rate of 15.28% for 1-octene.

[0161] Example 10

[0162] The catalytic application of the silica gel-supported nickel-vanadium bimetallic catalyst Cat3 in the ethylene polymerization reaction is as follows:

[0163] A 500ml reactor was heated to 110℃ and evacuated for 4 hours, during which nitrogen was purged three times. Then, ethylene was introduced twice under vacuum. After cooling to room temperature, 140ml of dehydrated and deoxygenated n-heptane and 60ml of 1-hexene were added. When the reactor temperature stabilized at 100℃, 0.45mL of a 1.1mol / L trioctylaluminum n-hexane solution and 200mg of catalyst Cat3 were added according to an Al / Cr ratio of 50. The mixture was stirred, and ethylene was introduced at 1MPa for polymerization. After 60 minutes, the ethylene inlet valve was closed, and the reactor was rapidly cooled using a low-temperature circulating water bath. The pressure was slowly released, and the product, polyethylene, was discharged. After drying and weighing, analysis showed that:

[0164] Polymerization activity = 1100 kg PE (mol Ni) -1 h -1 POP melting point = 91℃, weight-average molecular weight Mw = 9.3 * 10 4 The molecular weight distribution index (PDI) was 11.3 g / mol. HT 13C-NMR characterization revealed an insertion rate of 19.76% for 1-hexene.

[0165] Example 11

[0166] The catalytic application of the silica gel-supported nickel-vanadium bimetallic catalyst Cat4 in the ethylene polymerization reaction is as follows:

[0167] A 500ml reactor was heated to 125℃ and evacuated for 4 hours, during which nitrogen was purged three times. Then, ethylene was introduced twice under vacuum. After cooling to room temperature, 150ml of dehydrated and deoxygenated n-heptane and 50ml of 1-octene were added. When the reactor temperature stabilized at 100℃, 0.4mL of a 1.1mol / L solution of diethylaluminum chloride and toluene, along with 200mg of Cat4 catalyst, was added at an Al / Cr ratio of 80. The mixture was stirred, and ethylene was introduced at 3MPa for polymerization. After 60 minutes, the ethylene inlet valve was closed, and the reactor was rapidly cooled using a low-temperature circulating water bath. The pressure was slowly released, and the product, polyethylene, was discharged. After drying and weighing, analysis revealed the following:

[0168] Polymerization activity = 1700 kg POP (mol Ni) -1 h -1 PE melting point = 92℃, weight-average molecular weight Mw = 11.5 * 10 4 The molecular weight distribution index (PDI) was 11.7 g / mol. HT 13C-NMR characterization revealed an insertion rate of 13.79% for 1-octene.

[0169] Example 12

[0170] The catalytic application of the silica gel-supported nickel-vanadium bimetallic catalyst Cat5 in the ethylene polymerization reaction is as follows:

[0171] A 500ml reactor was heated to 115℃ and evacuated for 4 hours, during which nitrogen was purged three times. Then, ethylene was introduced twice under vacuum. After cooling to room temperature, 140ml of dehydrated and deoxygenated n-heptane and 60ml of 1-hexene were added. When the reactor temperature stabilized at 100℃, 0.72ml of a 1.1mol / L trioctylaluminum heptane solution and 200mg of catalyst Cat5 were added according to an Al / Cr ratio of 60. The mixture was stirred, and ethylene was introduced at 3MPa for polymerization. After 60 minutes, the ethylene inlet valve was closed, and the reactor was rapidly cooled using a low-temperature circulating water bath. The pressure was slowly released, and the product, polyethylene, was discharged. After drying and weighing, analysis revealed the following:

[0172] Polymerization activity = 1600 kg POP (mol Ni) -1 h -1 POP melting point = 87℃, weight-average molecular weight Mw = 9.5 * 10 4 The molecular weight distribution index (PDI) was 11.9 g / mol. HT 13C-NMR characterization revealed an insertion rate of 17.53% for 1-hexene.

[0173] Example 13

[0174] The catalytic application of the silica gel-supported nickel-vanadium bimetallic catalyst Cat6 in the ethylene polymerization reaction is as follows:

[0175] A 500ml reactor was heated to 125℃ and evacuated for 4 hours, during which nitrogen was purged three times. Then, ethylene was introduced twice under vacuum. After cooling to room temperature, 140ml of dehydrated and deoxygenated cyclohexane and 60ml of 1-hexene were added. When the reactor temperature stabilized at 100℃, 1.08ml of a 1.1mol / L toluene solution of triethylaluminum and 200mg of catalyst Cat6 were added according to an Al / Cr ratio of 90. The mixture was stirred, and ethylene was introduced at 6MPa for polymerization. After 30 minutes of reaction, the ethylene inlet valve was closed, and the reactor was rapidly cooled using a low-temperature circulating water bath. The pressure was slowly released, and the product, polyethylene, was discharged. After drying and weighing, analysis revealed the following:

[0176] Polymerization activity = 2300 kg POP (mol Ni) -1 h -1 POP melting point = 91℃, weight-average molecular weight = 7.1 * 10 4 The molecular weight distribution index (PDI) was 10.8 g / mol. HT 13C-NMR characterization revealed an 18.22% insertion rate of 1-hexene.

[0177] Example 14

[0178] The catalytic application of the silica gel-supported nickel-vanadium bimetallic catalyst Cat7 in the ethylene polymerization reaction is as follows:

[0179] A 500ml reactor was heated to 125℃ and evacuated for 4 hours, during which nitrogen was purged three times. Then, ethylene was introduced twice under vacuum. After cooling to room temperature, 140ml of dehydrated and deoxygenated cyclohexane and 60ml of 1-hexene were added. When the reactor temperature stabilized at 100℃, 1.08ml of a 1.1mol / L toluene solution of triethylaluminum and 200mg of Cat7 catalyst were added according to an Al / Cr ratio of 90. The mixture was stirred, and ethylene was introduced at 5MPa for polymerization. After 45 minutes, the ethylene inlet valve was closed, and the reactor was rapidly cooled using a low-temperature circulating water bath. The pressure was slowly released, and the product, polyethylene, was discharged. After drying and weighing, analysis revealed the following:

[0180] Polymerization activity = 1650 kg POP (mol Ni) -1 h -1 POP melting point = 103℃, weight-average molecular weight = 9.3 * 10 4 The molecular weight distribution index (PDI) was 11.5 g / mol. HT 13C-NMR characterization revealed an insertion rate of 13.17% for 1-hexene.

[0181] Comparative Example 1

[0182] The difference between this comparative example and Example 10 is that the type of catalyst is different; everything else is exactly the same as in Example 10. Specifically, in this comparative example, a silica-supported vanadium-nickel catalyst (Ni / V-SiO2) is used instead of the silica-supported nickel-vanadium bimetallic catalyst Cat1. The specific preparation process of the silica-supported vanadium-nickel catalyst (Ni / V-SiO2) in this comparative example is as follows:

[0183] 1) Weigh 10g of Grace Davison 955 silica gel and immerse it in an aqueous solution of ammonium metavanadate and nickel carbonate at 35℃ for 3h. The amount of ammonium metavanadate is 0.15wt% (34.5mg) of silica gel mass based on the vanadium loading, and the amount of nickel carbonate is 0.27wt% (30.3mg) of silica gel mass based on the nickel loading. Then evaporate the aqueous solution at 120℃ to obtain a solid powder. 2) Calcine the solid powder in a fluidized bed at 600℃ for 8h in an air atmosphere. Then turn off the heating, switch to a nitrogen atmosphere, and cool to room temperature to obtain the silica gel-supported vanadium-chromium catalyst.

[0184] The experimental results of this comparative example are as follows:

[0185] Polymerization activity = 630 kg POP (mol Cr) -1 h -1 POP has a melting point of 115℃ and a weight-average molecular weight Mw = 15.9 * 10⁻⁶. 4The molecular weight distribution index (PDI) was 13.2 g / mol. HT 13C-NMR characterization revealed an insertion rate of 1.19% for 1-octene.

[0186] Comparative Example 2

[0187] The difference between this comparative example and Example 7 is that the type of catalyst is different; everything else is exactly the same as in Example 7. Specifically, in this comparative example, a vanadium-free silica-supported nickel metal catalyst Cat8 is used instead of the silica-supported nickel-vanadium bimetallic catalyst Cat1. The specific preparation process of the silica-supported nickel bimetallic catalyst Cat8 in this comparative example is as follows:

[0188] Weigh 10g of Grace Davison 955 silica gel and calcine it in a fluidized bed at 600℃ for 8h. Then turn off the heating, switch to a nitrogen atmosphere, and cool to room temperature to obtain a solid powder. Under the protection of high-purity nitrogen, first transfer 5g of the solid powder to a container, add 150mL of purified n-hexane as a solvent using a syringe, and add 0.27wt% (153.0mg) of nickel metal complex C1 based on the nickel loading, which is the mass of the silica gel-supported vanadium catalyst. Adjust the temperature to 45℃ and stir continuously at a constant temperature for 5h. Then raise the temperature to 80℃ and increase the nitrogen flow rate. After the n-hexane is completely evaporated, the silica gel-supported nickel metal catalyst is obtained, denoted as Cat8.

[0189] The experimental results of this comparative example are as follows:

[0190] Polymerization activity = 630 kg POP (mol Cr) -1 h -1 POP has a melting point of 115℃ and a weight-average molecular weight Mw = 15.9 * 10⁻⁶. 4 The molecular weight distribution index (PDI) was 13.2 g / mol. HT 13C-NMR characterization revealed an insertion rate of 1.19% for 1-octene.

[0191] Comparative Example 3

[0192] The difference between this comparative example and Example 7 is that the type of catalyst is different; everything else is exactly the same as in Example 7. Specifically, in this comparative example, the silica-supported nickel-manganese bimetallic catalyst Cat9 is used instead of the silica-supported nickel-vanadium bimetallic catalyst Cat1. The specific preparation process of the silica-supported nickel-manganese bimetallic catalyst Cat9 in this comparative example is as follows:

[0193] Weigh 10g of Grace Davison 955 silica gel and immerse it in a manganese acetate aqueous solution at 35°C with stirring for 3 hours. The amount of manganese acetate used is 0.15wt% (47.3mg) of the silica gel mass, based on the manganese loading. Then, evaporate the aqueous solution at 120°C to obtain the impregnated silica gel.

[0194] In an air atmosphere, the impregnated silica gel was calcined at 600°C for 8 hours in a fluidized bed. Then, the heating was turned off, the atmosphere was switched to nitrogen, and the mixture was cooled to room temperature to obtain a solid powder.

[0195] Under the protection of high-purity nitrogen, 5g of solid powder was first transferred to a container, and 150mL of purified n-hexane was added as a solvent using a syringe. 153.0mg of nickel metal complex C1, which was 0.27wt% of the solid powder mass based on the nickel loading, was then added. The temperature was adjusted to 45℃ and stirred continuously at a constant temperature for 5h. Then the temperature was raised to 80℃ while the nitrogen flow rate was increased. After the n-hexane was completely evaporated, a silica gel-supported nickel-manganese bimetallic catalyst, denoted as Cat9, was obtained.

[0196] The experimental results of this comparative example are as follows:

[0197] Polymerization activity = 1580 kg POP (mol Cr) -1 h -1 POP has a melting point of 93℃ and a weight-average molecular weight Mw = 15.4 * 10⁻⁶. 4 The molecular weight distribution index (PDI) was 11.7 g / mol. HT 13C-NMR characterization revealed an insertion rate of 16.15% for 1-octene.

[0198] Based on the data comparison of Examples 8-14 and Comparative Example 1 above, it can be seen that the homopolymerization activity of the silica-supported nickel-vanadium bimetallic catalyst in the embodiments of the present invention can all reach 1100 kg POP (mol Cr). -1 h -1 The maximum is 2300 kg POP (mol Cr). -1 h -1 It is significantly superior to the 630 kg POP (mol Cr) of silica-supported vanadium-nickel catalyst (Ni / V-SiO2). -1 h -1 .

[0199] Based on the data from Example 8 and Comparative Examples 2-3 above, it can be seen that while the silica-supported nickel metal catalyst cat8, which directly uses silica gel and nickel metal complex C, exhibits high catalytic activity, its molecular weight distribution range is relatively narrow. Although adding a metal Mn salt can effectively broaden the molecular weight distribution range (see the results of the silica-supported nickel-manganese bimetallic catalyst Cat9 in Comparative Example 3), its catalytic activity is significantly reduced. In contrast, the silica-supported nickel-vanadium bimetallic catalyst cat1 of this invention, compared to the vanadium-free silica-supported nickel metal catalyst cat8, not only produces ethylene polymers with a wide molecular weight distribution but also improves the catalyst's catalytic activity, demonstrating excellent copolymerization performance.

[0200] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A silica gel-supported nickel-vanadium bimetallic catalyst, characterized in that, It has the structure shown in Equation 1: Formula 1: ; Among them, X, Y, R 1 –R 4 Each is independently selected from hydrogen, halogen, or any of the following groups: C 1-6 Alkyl, C 1-6 Alkyl group.

2. The silica-supported nickel-vanadium bimetallic catalyst according to claim 1, characterized in that, R 1 –R 4 Each is independently selected from hydrogen, fluorine, chlorine, bromine, or C. 1-6 alkyl; Or, X, Y, R 1 –R 4 Each is independently selected from any one of hydrogen, methyl, isopropyl, tert-butyl, fluorine, chlorine, or methoxy.

3. A method for preparing a silica gel-supported nickel-vanadium bimetallic catalyst, characterized in that, include: Silica gel and vanadium source are impregnated and stirred in a first solvent to obtain impregnated silica gel. The impregnated silica gel is then heat-treated to obtain a solid powder. The solid powder is then loaded with a nickel metal complex as shown in Formula 2 to obtain a catalyst. Formula 2: Among them, X, Y, R 1 –R 4 The definition is the same as that in claim 1 or 2.

4. The preparation method according to claim 3, characterized in that, The amount of vanadium source added is 0.1-1 wt% of the total weight of the silica gel, based on the loading of metallic vanadium. And / or, the amount of the nickel metal complex added is 0.1-1 wt% of the amount of silica gel, based on the loading of metallic nickel.

5. The preparation method according to claim 3 or 4, characterized in that, The first solvent is water or ethanol; The vanadium source is a vanadium-containing substance that is soluble in the first solvent; The soaking and stirring time is 1-12 hours; The heat treatment temperature is 500-1000℃; The heat treatment time is 6-12 hours; The heat treatment is followed by cooling in an inert atmosphere; The process of loading nickel metal complex onto solid powder is as follows: under an inert atmosphere, the solid powder is mixed with a second solvent and the nickel metal complex, stirred, and the second solvent is evaporated to obtain the catalyst.

6. The preparation method according to claim 5, characterized in that, The vanadium source is one or more of the following: ammonium metavanadate, vanadium nitrate, vanadium acetate, vanadium oxalate, vanadium phosphate, vanadium sulfate, vanadium sulfate, vanadium acetylacetone, vanadium diacetylacetone oxide, vanadium trichlorooxide, and vanadium tripropanol oxide. The impregnation and stirring time is 3-6 hours; The heat treatment temperature is 600-800℃.

7. The preparation method according to claim 5, characterized in that, The inert atmosphere is a nitrogen atmosphere; The stirring treatment temperature is 35-60℃, and the treatment time is 2-10h; The temperature for evaporation is 60-95℃; The second solvent includes one or more of the following: n-hexane, n-heptane, cyclohexane, n-pentane, methylcyclopentane, and methylcyclohexane.

8. The preparation method according to claim 3 or 4, characterized in that, The preparation method of the nickel metal complex includes: The acenaphthyl α-diimine ligand with the structure shown in Formula 3 was obtained by mixing and reacting the acenaphthyl α-diimine ligand with a nickel source containing nickel dibromide to obtain the nickel metal complex shown in Formula 2; the preparation process of the acenaphthyl α-diimine ligand shown in Formula 3 is as follows: the compounds shown in Formula 4 and Formula 5 are subjected to a synthetic reaction to obtain the acenaphthyl α-diimine ligand shown in Formula 3; Formula 3: , Formula 4: , Formula 5: .

9. The preparation method according to claim 8, characterized in that, The solvent used in the synthesis reaction of the compounds shown in Formulas 4 and 5 is C. 1-4 alcohol; The solvent used in the step of mixing the acenaphthene α-diimine ligand with a nickel source containing nickel dibromide is one or more of the following: tetrahydrofuran, anhydrous diethyl ether, pentane, cyclopentane, n-hexane, cyclohexane, heptane, methylcyclohexane, toluene, xylene, chlorobenzene, o-dichlorobenzene, o-xylene, and dichloromethane.

10. The preparation method according to claim 9, characterized in that, The solvent used in the synthesis reaction of the compounds shown in Formula 4 and Formula 5 is one or both of anhydrous methanol and anhydrous ethanol.

11. The application of the silica-supported nickel-vanadium bimetallic catalyst according to claim 1 or 2 in the ethylene polymerization reaction.

12. The application according to claim 11, characterized in that, Alkyl aluminum is also added to the ethylene polymerization reaction, and the molar ratio of the alkyl aluminum to nickel in the silica gel supported nickel-vanadium bimetallic catalyst is 5-200:

1. The process of ethylene polymerization is as follows: ethylene is mixed with a third solvent, comonomer, and alkyl aluminum, and then a silica-supported nickel-vanadium bimetallic catalyst is added to carry out the polymerization reaction.

13. The application according to claim 12, characterized in that, The molar ratio of nickel in the alkylaluminum and silica gel supported nickel-vanadium bimetallic catalyst is 10-100:1; Alkyl aluminum is one or more selected from trimethylaluminum, triethylaluminum, triisobutylaluminum, diethylaluminum chloride, trioctylaluminum, methylaluminoxane, modified methylaluminoxane, and ethylaluminoxane; Ethylene and / or the third solvent are dehydrated and deoxygenated before being mixed with the comonomer; The polymerization conditions are 60-150℃, 0.5-8MPa, and 10-240min; The third solvent includes one or more of n-hexane, n-heptane, methylcyclohexane, toluene, or cyclohexane; The comonomers include one or more of 1-butene, 1-hexene, or 1-octene.

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