A catalyst, a method for preparing the same, and a method for ethylene homopolymerization

Abstract

This invention provides a catalyst and its preparation method, as well as a method for homopolymerizing ethylene. The catalyst comprises a nickel complex, a co-catalyst A, and a support. The nickel complex has a structure as shown in Formula I: Formula I. The nickel complex of this invention exhibits good stability to water and oxygen, and can be stably stored in air at room temperature, significantly reducing the cost of the preparation, purification, storage, and use of the main catalyst, and simplifying the operation. The catalyst of this invention exhibits good catalytic activity and good thermal stability when used in the homopolymerization reaction of ethylene. Its activity can also be released steadily, inhibiting severe polymer sticking to the reactor and solving the problem of difficult reactor cleaning. Even under high temperature conditions, it can maintain stable catalytic activity and has good prospects for industrial application.

Description

Technical Field

[0001] This invention relates to a catalyst and its preparation method, as well as a method for homopolymerizing ethylene, belonging to the field of polyolefin catalysis technology. Background Technology

[0002] Polyolefin materials are among the most widely used and produced polymer materials. They are mainly produced by homopolymerization and / or copolymerization of ethylene, propylene and α-olefins (1-butene, 1-hexene, 1-octene, etc.), among which polyethylene and polypropylene dominate.

[0003] The core of polyolefin material production lies in the catalyst. Metallocene catalysts are currently commonly used catalysts for olefin polymerization. However, these catalysts have a high affinity for oxygen and will rapidly deactivate upon contact with water and air, accompanied by exothermic reactions and even the risk of spontaneous combustion. Strict isolation from water and oxygen is required during production and operation, which significantly increases the cost of metallocene catalyst preparation, purification, storage, and use. Therefore, the development of novel transition metal catalysts that are reliable, stable in water and oxygen, easy to prepare, and low in cost has become an urgent need in this field.

[0004] Compared to metallocene catalysts, post-transition metal catalysts, especially α-diimine complexes, offer advantages such as high polymerization activity, weak oxyphilicity, stable properties, and simple preparation, making them suitable for ethylene polymerization and copolymerization of ethylene with various α-olefins. In 1995, Brookhart's research group, funded by DuPont, first reported that α-diimine nickel complexes (structure shown in Formula II) could efficiently catalyze the polymerization of ethylene to high-molecular-weight polyethylene at room temperature (J. Am. Chem. Soc., 1995, 117, 6414-6415). However, these post-transition metal catalysts generally have poor thermal stability, completely deactivating at temperatures of 60°C and above (Organometallics. 2017, 36, 1196-1203.). Furthermore, the high polymer viscosity hinders monomer diffusion, and the active metal cation centers are embedded, leading to a significant decrease in catalyst activity with prolonged polymerization time. Additionally, severe polymer adhesion to the reactor and difficulty in cleaning the reactor severely limit their industrial application.

[0005] Formula II.

[0006] Common loading methods for post-transition metal catalysts include direct loading via physical adsorption and loading the catalyst onto the support via chemical bonding. However, direct loading via physical adsorption results in weak bonding between the catalyst and the support, making it easy for the catalyst to separate from the support during polymerization. While loading via chemical bonding can enhance the bonding between the catalyst and the support, it still has some drawbacks. On the one hand, the high-temperature resistance of the catalyst needs to be improved, especially the activity and lifetime of the catalyst at higher temperatures. On the other hand, the synthesis steps of catalysts containing anchoring groups are more complex, which increases the preparation cost.

[0007] Therefore, it is of great significance to develop a catalyst system for non-acenaphthoquinone framework α-diimine post-transition metal complexes that has both excellent thermal stability and a simple synthesis method. Summary of the Invention

[0008] To solve the above-mentioned technical problems, the present invention aims to provide a catalyst and its preparation method, as well as a method for homopolymerization of ethylene. When the catalyst of the present invention is used for homopolymerization of ethylene, it has good thermal stability and catalytic activity.

[0009] To achieve the above objectives, in a first aspect, the present invention provides a catalyst, wherein the catalyst comprises a nickel complex, a co-catalyst A, and a support;

[0010] The nickel complex has the structure shown in Formula I:

[0011] Formula I;

[0012] In equation I, R1, R2, R3, R4, R5, R6, R7, R8, R9, R 10 Each is independently selected from H, unsubstituted, or derived from R. 11 C with substituent group 1-6 Alkyl, C 2-6 alkenyl, C 6-10 Aryl, halogen, hydroxyl, C 1-6 Alkoxy and -NR 12 R 13 One or more combinations of R; 11 Selected from halogens, unsubstituted or derived from C 1-6 One or more alkyl groups substituted with one or more phenyl groups; R 12 and R 13 Each is independently selected from hydrogen and C. 1-6 One or more of the alkyl groups;

[0013] Each of X is independently selected from halogens.

[0014] According to a specific embodiment of the present invention, preferably, in formula I, R1, R2, R3, R4, R5, R6, R7, R8, R9, R 10 Each is independently selected from H, unsubstituted, or derived from R. 11 C with substituent group 1-4 Alkyl, C 6-8 Aryl, fluorine, chlorine, hydroxyl, C 1-4 One or more combinations of alkoxy groups; R 11 Selected from halogens, unsubstituted or derived from C 1-4 One or more alkyl groups substituted with one or more phenyl groups;

[0015] X is bromine and / or chlorine, each independently.

[0016] According to a specific embodiment of the present invention, preferably, in formula I, R1, R3, R5, R6, R8, R 10 Each is independently selected from H, unsubstituted, or derived from R. 11 Substituted methyl group, unsubstituted methyl group, or methyl group composed of R 11 Ethyl groups substituted with groups, unsubstituted ethyl groups, or ethyl groups derived from R 11 Substituted n-propyl group, unsubstituted or derived from R 11 A combination of one or more of the following groups: isopropyl, methoxy, ethoxy, propoxy, and isopropoxy; R 11 Selected from phenyl, phenyl groups substituted with one or more groups selected from methyl, ethyl, n-propyl, and propoxy, and fluorine groups selected from one or more combinations thereof;

[0017] R2, R4, R7, and R9 are all H;

[0018] X is all bromine.

[0019] According to a specific embodiment of the present invention, preferably, the nickel complex represented by Formula I has one of the following structures:

[0020] .

[0021] According to a specific embodiment of the present invention, preferably, the cocatalyst A is selected from alkylaluminoxane A and / or alkylaluminum compound A.

[0022] According to a specific embodiment of the present invention, preferably, the alkylaluminoxane A is selected from methylaluminoxane and / or modified methylaluminoxane, more preferably methylaluminoxane.

[0023] According to a specific embodiment of the present invention, preferably, the alkyl aluminum compound A is selected from one or more combinations of diethylaluminum chloride (AlEt2Cl), sesquiethylaluminum chloride (EASC), ethylaluminum dichloride, trimethylaluminum, triethylaluminum, triisobutylaluminum, and tributylaluminum. More preferably, it is diethylaluminum chloride and / or sesquiethylaluminum chloride.

[0024] According to a specific embodiment of the present invention, preferably, the carrier is selected from one or more combinations of silica gel (e.g., SYLOPOL® 2408, Changzhou Haohua Chemical Co., Ltd.), magnesium dichloride, and alumina.

[0025] According to a specific embodiment of the present invention, preferably, the molar ratio of the co-catalyst A, calculated as aluminum, to the nickel complex, calculated as nickel, is (50-5000):1.

[0026] According to a specific embodiment of the present invention, preferably, the ratio of the co-catalyst A to the support is 0.5-500 mmol / g, more preferably 1-100 mmol / g, and even more preferably 5-50 mmol / g.

[0027] According to a specific embodiment of the present invention, preferably, the ratio of the nickel complex to the carrier is 0.01-0.1 mmol / g, more preferably 0.02-0.1 mmol / g.

[0028] According to a specific embodiment of the present invention, preferably, the preparation method of the nickel complex includes the following steps:

[0029] (1) Compound C-1 is subjected to a first condensation reaction with an aniline compound to obtain intermediate product I or intermediate product II; wherein the aniline compound is compound C-2 and / or compound C-3;

[0030] Optionally, the method further includes: subjecting the intermediate product I to the aniline compound in a second condensation reaction to obtain intermediate product II;

[0031] (2) The intermediate product II is subjected to a coordination reaction with the nickel catalyst precursor to obtain the nickel complex shown in Formula I;

[0032]

[0033] Compound C-1; Compound C-2; Compound C-3;

[0034]

[0035] Intermediate product I; Intermediate product II;

[0036] R in compounds C-2, C-3, intermediate I, and intermediate II 1 R 2 R 3 R 4 R 5 R 6 R 7 R 8 R 9 and R 10 The definition corresponds to the definition described in the first aspect above.

[0037] In the above method for preparing nickel complexes, preferably, in step (1), the first condensation reaction and the second condensation reaction are carried out under the action of an additive, wherein the additive is selected from one or more combinations of formic acid, p-toluenesulfonic acid, zinc chloride, and acetic acid.

[0038] In the above method for preparing nickel complexes, preferably, in step (1), the molar ratio of compound C-1 to the aniline compound is 1:(1-3).

[0039] In the above method for preparing nickel complexes, preferably, in step (1), the conditions for the first condensation reaction and the second condensation reaction include: a temperature of 10-200 °C and a time of 2-24 h.

[0040] In the above method for preparing nickel complexes, preferably, in step (1), the first condensation reaction and the second condensation reaction are carried out in the presence of organic solvent I, wherein organic solvent I is selected from one or more combinations of methanol, ethanol, acetic acid, toluene, and acetonitrile. More preferably, organic solvent I is selected from one or more combinations of methanol, acetic acid, and toluene.

[0041] In the above method for preparing nickel complexes, preferably, in step (1), the method further includes: subjecting the material I obtained from the first condensation reaction and the second condensation reaction to a first purification. More preferably, the first purification operation includes: concentrating, washing, and drying the material I, or filtering, washing, separating, and drying the material I. The washing agent is selected from one or a combination of two or more of methanol, ethanol, acetic acid, diethyl ether, and potassium oxalate.

[0042] The present invention does not have any special requirements for the specific operations of concentration, washing, drying, filtration and separation. Those skilled in the art can perform these operations according to conventional technical means in the field. The present invention will not elaborate further here, and those skilled in the art should not understand this as a limitation of the present invention.

[0043] In the above method for preparing nickel complexes, preferably, in step (2), the coordination reaction is carried out under a protective atmosphere. More preferably, the protective atmosphere is selected from nitrogen, helium, and argon.

[0044] In the above method for preparing nickel complexes, preferably, in step (2), the coordination reaction is carried out in the presence of organic solvent II, wherein organic solvent II is selected from one or more combinations of dichloromethane, trichloromethane, tetrahydrofuran, 1,4-dioxane, and toluene. More preferably, organic solvent II is dichloromethane.

[0045] In the above method for preparing the nickel complex, preferably, in step (2), the nickel catalyst precursor is nickel dimethyl ether dichloride and / or nickel dimethyl ether dibromide. More preferably, the nickel catalyst precursor is nickel dimethyl ether dibromide.

[0046] In the above method for preparing nickel complexes, preferably, in step (2), the molar ratio of intermediate product II to nickel catalyst precursor is (1-2):1.

[0047] In the above method for preparing nickel complexes, preferably, in step (2), the conditions for the coordination reaction include: a temperature of 15-35 °C and a time of 2-24 h; more preferably, the conditions for the coordination reaction include: a temperature of 20-30 °C and a time of 10-14 h. Exemplarily, the conditions for the coordination reaction include: a temperature of 25 °C and a time of 12 h.

[0048] In the above method for preparing nickel complexes, preferably, in step (2), the method further includes: subjecting material II obtained from the coordination reaction to a second purification. More preferably, the second purification operation includes: concentrating material II to obtain a solid product, washing the solid product with a detergent, and / or recrystallizing the solid product in a mixed solution of organic solvent III and an alkane. More preferably, the detergent is selected from one or more combinations of anhydrous diethyl ether, petroleum ether, and acetone, the organic solvent III is selected from one or more combinations of dichloromethane, trichloromethane, and tetrahydrofuran, and the alkane is hexane and / or pentane. Exemplarily, the detergent is anhydrous diethyl ether, and the organic solvent III is dichloromethane.

[0049] The present invention does not have any special requirements for the specific operations of concentration, washing and recrystallization. Those skilled in the art can perform these operations according to conventional technical means in the field. The present invention will not elaborate further here, and those skilled in the art should not understand this as a limitation of the present invention.

[0050] In the above method for preparing the nickel complex, preferably, the method further includes the operation of preparing compound C-1, including:

[0051] The phenanthrene was diacylated to give compound C-1.

[0052] In the preparation of compound C-1, preferably, the diacylation reaction is carried out in the presence of a Lewis acid catalyst, an acylation reagent, and a solvent.

[0053] In the preparation of compound C-1, preferably, the molar ratio of phenanthrene to Lewis acid catalyst is 1:(1-3).

[0054] In the preparation of compound C-1, preferably, the Lewis acid catalyst is selected from one or more of aluminum tribromide, aluminum trichloride, and ferric chloride.

[0055] In the preparation of compound C-1, preferably, the molar ratio of phenanthrene to the acylation reagent is 1:(1-2).

[0056] In the preparation of compound C-1, preferably, the acylation agent is selected from one or more combinations of oxaloyl bromide, acetyl chloride, and benzoyl chloride.

[0057] In the preparation of compound C-1, preferably, the solvent is selected from one or more combinations of carbon disulfide, dichloromethane, and nitrobenzene.

[0058] In the preparation of compound C-1, preferably, the diacylation reaction is first carried out at a temperature of -50 ℃ to -20 ℃ for 2-4 h, and then at a temperature of 20-30 ℃ for 1-3 h.

[0059] In the preparation of compound C-1, preferably, the diacylation reaction is carried out under a protective atmosphere. More preferably, the protective atmosphere is selected from nitrogen, helium, and argon.

[0060] In the preparation of compound C-1, preferably, the diacylation reaction further includes: post-treatment of the liquid obtained from the diacylation reaction. The present invention does not require specific operations for the post-treatment, but it may include: removing the protective atmosphere from the liquid, then mixing it with a terminator to terminate the reaction, and then separating, washing, and concentrating the reaction solution after the termination reaction to obtain compound C-1. Exemplarily, the terminator is ice water, the separation solution is dichloromethane, the washing agent is deionized water and saturated brine, and the concentration is achieved using silica gel column chromatography.

[0061] The present invention does not have any special requirements for the specific operations of separation, washing and concentration. Those skilled in the art can perform these operations according to conventional technical means in the field. The present invention will not elaborate further here, and those skilled in the art should not understand this as a limitation of the present invention.

[0062] Secondly, the present invention also provides a method for preparing the above-mentioned catalyst, wherein the preparation method includes the following steps:

[0063] Under a protective atmosphere, the support, co-catalyst A, and solvent are mixed to obtain a dispersion.

[0064] The dispersion was reacted with the nickel complex at 20-60 °C, and after post-treatment, a catalyst was obtained.

[0065] In the above-described method for preparing the catalyst, preferably, the dispersion and the nickel complex are reacted at 20-60 °C for 1-6 h, more preferably for 3-6 h.

[0066] In the above-mentioned method for preparing the catalyst, preferably, the support is first activated at 400-800 °C for 1-7 h.

[0067] In the above-described method for preparing the catalyst, preferably, under a protective atmosphere, the support, co-catalyst A, and solvent are mixed and stirred at 20-60 °C for 1-6 h to obtain a dispersion. More preferably, after mixing and stirring, the mixture is cooled, allowed to settle, the supernatant is removed, washed, allowed to settle again, the supernatant is removed, and then 10 mL of solvent is added to obtain the dispersion. The solvent is further preferably toluene.

[0068] In the above-described method for preparing the catalyst, the present invention does not require the post-processing steps, which may include, for example, allowing the catalyst to stand, removing the solvent, washing, and vacuum drying to obtain a powdered catalyst for use in subsequent ethylene polymerization reactions.

[0069] In the above-described method for preparing the catalyst, preferably, the protective atmosphere is selected from nitrogen, helium, and argon.

[0070] Thirdly, the present invention also provides a method for homopolymerization of ethylene, wherein the method includes:

[0071] Ethylene undergoes homopolymerization in the presence of an organic solvent, a catalyst, and co-catalyst B.

[0072] The catalyst is the catalyst described above or a catalyst prepared by the method described above.

[0073] According to a specific embodiment of the present invention, preferably, the temperature of the homopolymerization reaction is 0-150 °C and the time is 0.1-6 h; more preferably, the temperature of the homopolymerization reaction is 20-100 °C and the time is 0.2-2 h.

[0074] According to a specific embodiment of the present invention, preferably, the pressure of the homopolymerization reaction is 1-40 atm, more preferably 5-10 atm.

[0075] According to a specific embodiment of the present invention, preferably, the molar ratio of the co-catalyst B, calculated as aluminum, to the catalyst, calculated as nickel, is (50-1000):1, more preferably (50-500):1.

[0076] According to a specific embodiment of the present invention, preferably, the cocatalyst B is selected from alkylaluminoxane B and / or alkylaluminum compound B.

[0077] According to a specific embodiment of the present invention, preferably, the alkylaluminoxane B is selected from methylaluminoxane and / or modified methylaluminoxane, more preferably methylaluminoxane.

[0078] According to a specific embodiment of the present invention, preferably, the alkyl aluminum compound B is selected from one or more combinations of diethylaluminum chloride, sesquiethylaluminum chloride, diethylaluminum chloride, trimethylaluminum, triethylaluminum, triisobutylaluminum, and tributylaluminum, more preferably diethylaluminum chloride.

[0079] According to a specific embodiment of the present invention, preferably, the organic solvent is selected from one or more of hexane, pentane, heptane, toluene, xylene, chlorobenzene, benzene, and dichloromethane; more preferably, it is selected from one or more of hexane, heptane, and toluene.

[0080] According to a specific embodiment of the present invention, preferably, the present invention does not have special requirements for the specific operation of the homopolymerization reaction. For example, it may include: adding an organic solvent and a co-catalyst to a dry reaction vessel under an ethylene atmosphere; subsequently adding a nickel complex, introducing ethylene until the polymerization pressure reaches a predetermined value, and carrying out a homopolymerization reaction; after the reaction is completed, stopping the introduction of ethylene gas and depressurizing, and after washing and drying, obtaining polyethylene.

[0081] Compared with the prior art, the present invention has the following beneficial effects:

[0082] The nickel complex of the present invention exhibits good stability to water and oxygen, and can be stably stored in air at room temperature, which can significantly reduce the cost of the preparation, purification, storage and use of the main catalyst, and is simple to operate.

[0083] The catalyst of this invention is easy to prepare and has a relatively low cost. When applied to the homopolymerization reaction of ethylene, it has good catalytic activity and good thermal stability. Its activity can also be released steadily, which inhibits the serious sticking of polymer to the reactor and solves the problem of difficult cleaning of the reactor. Even under high temperature conditions, it can maintain stable catalytic activity and has good prospects for industrial application. Detailed Implementation

[0084] In order to provide a clearer understanding of the technical features, objectives and beneficial effects of the present invention, the technical solution of the present invention will now be described in detail below, but it should not be construed as limiting the scope of implementation of the present invention.

[0085] Unless otherwise specified, the analytical and testing methods described in the following examples and comparative examples are conventional methods.

[0086] Molecular formula: determined based on the chemical structure of the chemical substance;

[0087] Elemental analysis: Results obtained using organic elemental analyzer methods;

[0088] Catalytic activity: expressed as "g of PE (mol of Ni)". -1 h -1 ", which is the number of grams of polyethylene (PE) produced per hour per mole of nickel (Ni) catalyst, a figure obtained through ethylene polymerization experiments;

[0089] Hydrogen nuclear magnetic resonance spectrum: obtained by Bruker 400 MHz nuclear magnetic resonance spectrometer.

[0090] Unless otherwise specified, the reagents and materials used in the following examples and comparative examples are commercially available.

[0091] Fibre: Purchased from Adamas Reagents Ltd., brand name 86163B;

[0092] 2,6-Diisopropylaniline: purchased from Adamas Reagents Ltd., grade 40849F;

[0093] Ethylene glycol dimethyl ether nickel bromide: purchased from Sigma-Aldridge, grade 406341;

[0094] 2,6-Bis(diphenylmethyl)-4-methylaniline: purchased from Adamas Reagent Co., Ltd., grade 3938378C;

[0095] 2,6-Dimethylaniline: purchased from Adamas Reagents Ltd., grade 87623F;

[0096] 2,4,6-Trimethylaniline: purchased from Adamas Reagent Co., Ltd., grade 87835D;

[0097] Methylaluminoxane: purchased from Sigma-Aldridge, grade 404594;

[0098] Diethylaluminum chloride: purchased from Adamas Reagents Ltd., grade 91609G, specification 1.0 M;

[0099] Silicone: Purchased from Changzhou Haohua Chemical Co., Ltd., SYLOPOL® 2408.

[0100] Unless otherwise specified, room temperature in the following examples and comparative examples refers to 25±1 ℃.

[0101] Preparation Example 1

[0102] The preparation method of nickel complex N-1 is as follows:

[0103] (a) Synthesis of compound C-1:

[0104] (1) Under a nitrogen atmosphere, 10 mL of carbon disulfide and 5.6 mmol of aluminum tribromide were added to a 50 mL Schlenk flask with a stir bar. The mixture was cooled to -40 °C, and then 2.81 mmol of phenanthrene (1.0 equivalent), 2.81 mol of oxaloyl bromide (1.0 equivalent) and 4 mL of carbon disulfide were added. The mixture was stirred at -40 °C for 3 h, and then the cold bath was removed. The mixture was stirred at room temperature for 2 h to obtain the reaction solution.

[0105] (2) After the reaction is complete, remove the nitrogen protection and slowly add 30 mL of ice water to the above reaction solution to quench the reaction. After the quenching reaction is complete, add 30 mL of dichloromethane to the reaction solution and separate the organic phase using a separatory funnel. Wash the organic phase three times with deionized water, each time with 20 mL, and wash the organic phase once with saturated saline solution, with a volume of 20 mL, to obtain the product.

[0106] (3) The product was concentrated and the crude product was purified by silica gel column chromatography (eluent: petroleum ether: ethyl acetate = 10:1 to 3:1) to give 508 mg of compound C-1 (acetylphenanthrene-4,5-dione, structure shown below), with a yield of 78%.

[0107] C-1;

[0108] 400 MHz 1H NMR spectrum data for compound C-1: 1H-NMR (400M, CDCl3): δ8.87 (d, J = 8.3Hz, 1H), 8.72 (d, J = 8.2 Hz, 1H), 8.40 (s, 1H), 8.20-8.17 (m, 2H), 7.98 (dd,J = 8.3 Hz, 7.2 Hz, 1H), 7.94 (ddd, J = 8.3 Hz, 7.2 Hz, 1.3 Hz, 1H), 7.84 (ddd, J = 8.3 Hz, 7.2 Hz, 1.2 Hz, 1H).

[0109] GC-MS (EI) of compound C-1, m / z = 232.1.

[0110] (II) Synthesis of intermediate product II-1:

[0111] To a mixture of 19 mL methanol and 1 mL formic acid, 1.0 mmol of compound C-1 (1.0 equivalent) and 2.2 mmol of 2,6-dimethylaniline (2.2 equivalent) were added. The resulting mixture was stirred at room temperature for 12 h, then concentrated to obtain a solid crude product. Finally, the crude product was washed with cold methanol, and the resulting solid was dried to give 401 mg of intermediate II-1 ((4E,5E)-N4,N5-bis(2,6-dimethylphenyl)acetylphenanthrene-4,5-diimide, structure shown below), in 91% yield.

[0112] Intermediate product II-1;

[0113] LC-MS (ESI) of intermediate II-1, m / z [M+1] + = 439.6.

[0114] (III) Synthesis of nickel complex N-1:

[0115] In a glove box under nitrogen atmosphere, 1.1 mmol of intermediate II-1 (1.1 equivalent), 1.0 mmol of ethylene glycol dimethyl ether nickel bromide (1.0 equivalent), and 5 mL of dry dichloromethane were added to a 4 mL sample vial equipped with a stir bar. The mixture was stirred at room temperature for 12 h, and then concentrated to obtain a dark red solid crude product. Finally, the product was washed with anhydrous diethyl ether (20 mL of diethyl ether was used for each wash, for a total of three washes). The dark red solid was collected and dried to obtain 578 mg of nickel complex N-1 (structure shown below), with a yield of 88%.

[0116] N-1;

[0117] Nickel complex N-1 (C 32 H 26 Elemental analysis of Br₂N₂Ni: Calculated C, 58.49%; H, 3.99%; N, 4.26%. Measured values: C, 58.90%; H, 3.78%; N, 4.16%.

[0118] The elemental analysis data of nickel complex N-1 showed no significant changes after being exposed to air for two weeks.

[0119] Preparation Example 2

[0120] The preparation method of nickel complex N-6 is as follows:

[0121] (a) Synthesis of compound C-1:

[0122] Compound C-1 was synthesized using the same procedure as step (a) of Preparation Example 1;

[0123] (II) Synthesis of intermediate product I-2:

[0124] To a mixture of 19 mL methanol and 1 mL formic acid, 1.0 mmol of compound C-1 (1.0 equivalent) and 1.1 mmol of 2,4,6-trimethylaniline (1.1 equivalent) were added. The resulting mixture was stirred at room temperature for 12 h and then concentrated to obtain a solid crude product. The crude product was purified by silica gel column chromatography (eluent: petroleum ether: ethyl acetate = 10:1 to 3:1) to give 349 mg of intermediate I-2 ((E)-4-(2,4,6-trimethylphenylamino)acetylphenanthrene-5(4H)-one, structure shown below), in 95% yield.

[0125] Intermediate product I-2.

[0126] LC-MS (ESI) of intermediate I-2, m / z [M+1] + = 350.1.

[0127] (III) Synthesis of intermediate product II-2:

[0128] 0.1 mmol of p-toluenesulfonic acid (0.1 equivalent) was added to 5 mL of a dry toluene solution containing 1.0 mmol of intermediate I-2 and 1.1 mmol of 2,6-bis(diphenylmethyl)-4-methylaniline (1.1 equivalent). The reaction mixture was heated under reflux at 160 °C for 12 h, and then concentrated to obtain a solid crude product. Finally, the crude product was washed with cold ethanol to give 323 mg of intermediate I-2 ((4E,5E)-N5-(2,6-bis(diphenylmethyl)-4-methylphenyl)-N4-(2,4,6-trimethylphenyl)acetylphenanthrene-4,5-diimide, structure shown below), in a yield of 42%.

[0129] Intermediate product II-2;

[0130] LC-MS (ESI) of intermediate II-2, m / z [M+1] + = 772.4.

[0131] (iv) Synthesis of nickel complex N-6:

[0132] Nickel complex N-6 was synthesized using a similar procedure to that used in step (iii) of Preparation Example 1, except that 1.1 mmol of intermediate II-2 (1.1 equivalent), 1.0 mmol of ethylene glycol dimethyl ether nickel bromide (1.0 equivalent), and 5 mL of dry dichloromethane were added.

[0133] The nickel complex N-6 (structure shown below) was prepared in a yield of 880 mg, with a yield of 89%.

[0134] N-6;

[0135] Nickel complex N-6 (C 58 H 46 Elemental analysis of Br₂N₂Ni: Calculated C, 70.40%; H, 4.69%; N, 2.83%. Measured values: C, 70.64%; H, 4.78%; N, 2.56%.

[0136] The elemental analysis data of nickel complex N-6 showed no significant changes after being exposed to air for two weeks.

[0137] Preparation Example 3

[0138] The preparation method of nickel complex N-7 is as follows:

[0139] (a) Synthesis of compound C-1:

[0140] Compound C-1 was synthesized using the same procedure as step (a) of Preparation Example 1;

[0141] (II) Synthesis of intermediate product I-3:

[0142] 0.1 mmol of p-toluenesulfonic acid (0.1 equivalent) was added to 5 mL of a dry toluene solution containing 1 mmol of compound C-1 (1.0 equivalent) and 1.1 mmol of 2,6-diisopropylaniline (1.1 equivalent). The reaction mixture was heated under reflux at 160 °C for 12 h, and then concentrated to obtain a solid crude product. Finally, the crude product was washed with cold ethanol to give 336 mg of intermediate I-3 ((E)-4-(2,6-diisopropylphenylamino)acetylphenanthrene-5(4H)-one, structure shown below), in 86% yield.

[0143] Intermediate product I-3;

[0144] LC-MS (ESI) of intermediate I-3, m / z [M+1] + = 392.2.

[0145] (III) Synthesis of intermediate product II-3:

[0146] Intermediate II-3 was synthesized using a similar process to that used in step (ii) of Preparation Example 3, except that in step (iii), intermediate I-3 was used instead of compound C-1 from step (ii), and 2,6-bis(diphenylmethyl)-4-methylaniline was used instead of 2,6-diisopropylaniline. 414 mg of intermediate II-2 ((4E,5E)-N5-(2,6-bis(diphenylmethyl)-4-methylphenyl)-N4-(2,6-diisopropylphenyl)acetylphenanthrene-4,5-diimide, structure shown below) was obtained in 51% yield.

[0147] Intermediate product II-3;

[0148] LC-MS (ESI) of intermediate II-3, m / z [M+1] + = 814.4.

[0149] (iv) Synthesis of nickel complex N-7:

[0150] Nickel complex N-7 was synthesized using a similar process to that used in step (iii) of Preparation Example 1. The difference was that in step (iv) of Preparation Example 3, intermediate II-3 was used instead of intermediate II-1 in step (iii) of Preparation Example 1, and the amounts of intermediate II-3, nickel dimethyl ether bromide (EDGB), and dichloromethane were 0.33 mmol, 0.30 mmol, and 2 mL, respectively. 262 mg of nickel complex N-7 (structure shown below) was obtained, with a yield of 85%.

[0151] N-7.

[0152] Nickel complex N-7 (C 61 H 52 Elemental analysis of Br₂N₂Ni: Calculated C, 71.02%; H, 5.08%; N, 2.72%. Measured values: C, 70.88%; H, 4.96%; N, 2.61%.

[0153] The elemental analysis data of nickel complex N-7 showed no significant changes after being exposed to air for two weeks.

[0154] Preparation Example 4

[0155] The preparation method of nickel complex N-13 is as follows:

[0156] (a) Synthesis of compound C-1:

[0157] Compound C-1 was synthesized using the same procedure as step (a) of Preparation Example 1;

[0158] (II) Synthesis of intermediate product II-4:

[0159] To a 10 mL acetic acid solution containing 1.0 mmol of compound C-1 (1.0 equivalent) and 2.5 mmol of 2,6-bis(diphenylmethyl)-4-methylaniline (2.5 equivalent), 1.2 mmol of anhydrous zinc chloride (1.2 equivalent) was added. The reaction mixture was heated under reflux at 160 °C for 20 h. After the reaction was complete, the reaction mixture was cooled to room temperature, filtered, and the red solid precipitate was collected. The solid was then washed three times with acetic acid and diethyl ether. The resulting red solid was dissolved in dichloromethane, and the organic phase was washed with a saturated potassium oxalate aqueous solution. Finally, the organic phase was separated, collected, and dried to give 472 mg of intermediate II-4 ((4E,5E)-N4,N5-bis(2,6-bis(diphenylmethyl)-4-methylphenyl)acetylphenanthrene-4,5-diimide, structure shown below), in a yield of 44%.

[0160] Intermediate product II-4;

[0161] LC-MS (ESI) of intermediate II-4, m / z [M+1] + = 1076.2.

[0162] (III) Synthesis of nickel complex N-13:

[0163] In a glove box under nitrogen atmosphere, 0.55 mmol of intermediate II-4 (1.1 equivalent), 0.50 mmol of ethylene glycol dimethyl ether nickel bromide (1.0 equivalent), and 10 mL of dry dichloromethane were added to a 25 mL sample vial equipped with a stir bar. The mixture was stirred at room temperature for 12 h, and then concentrated to obtain a dark red solid crude product. Finally, the product was washed with anhydrous diethyl ether (20 mL of diethyl ether was used for each wash, for a total of three washes). The dark red solid was collected and dried to obtain 555 mg of nickel complex N-13 (structure shown below), with a yield of 86%.

[0164] N-13;

[0165] Nickel complex N-13 (C 82 H 62 Elemental analysis of Br₂N₂Ni: Calculated C, 76.12%; H, 4.83%; N, 2.17%. Measured values: C, 75.90%; H, 4.78%; N, 2.38%.

[0166] The elemental analysis data of nickel complex N-13 showed no significant changes after being exposed to air for two weeks.

[0167] Example 1

[0168] This embodiment provides a method for preparing a catalyst, specifically including the following steps:

[0169] Inside a glove box, 1 g of silica gel (SYLOPOL® 2408, activated at 600 °C for 2 h) was added to a Schlenk flask, along with 10 mL of toluene solvent. The mixture was stirred and dispersed for 10 min. Subsequently, 5.0 mL of a 0.1 g / mL MAO toluene solution was slowly added dropwise. The mixture was stirred at 40 °C for 3 h. After the reaction was complete, the mixture was cooled and allowed to settle for 1 h. The supernatant was removed. The mixture was washed with 10 mL of toluene, allowed to settle for 1 h, and the supernatant was removed again. Then, 10 mL of toluene was added to disperse the mixture, resulting in a dispersion.

[0170] Add 33 mg of nickel complex N-1 to the above dispersion, stir at 40 °C for 3 h, after the reaction is completed, cool down, let stand and settle for 1 h, remove the supernatant; wash with toluene 3 times, then wash with n-hexane once, and finally vacuum dry the solvent to obtain a free-flowing solid powder, which is catalyst Cat 1-1, and store it in a glove box for subsequent olefin polymerization reaction.

[0171] Example 2

[0172] This embodiment provides a method for preparing a catalyst, which differs from Example 1 only in that:

[0173] Nickel complex N-6 was added to the dispersion; the catalyst Cat 1-2 was finally prepared.

[0174] Example 3

[0175] This embodiment provides a method for preparing a catalyst, which differs from Example 1 only in that:

[0176] Nickel complex N-7 was added to the dispersion; the catalyst Cat 1-3 was finally prepared.

[0177] Example 4

[0178] This embodiment provides a method for preparing a catalyst, which differs from Example 1 only in that:

[0179] Nickel complex N-13 was added to the dispersion; the catalyst Cat 1-4 was finally prepared.

[0180] Experimental Example 1

[0181] This experimental example provides a method for homopolymerization of ethylene, specifically including the following steps:

[0182] The 2 L stainless steel polymerization reactor was purged with high-purity nitrogen at least three times, and then purged with ethylene three times. After the gas purging was completed, 400 mL of n-hexane was added to the reactor, stirring was started, 1 mmol of AlEt2Cl (1 mL) was added, and the reactor was flushed with 200 mL of n-hexane to ensure that AlEt2Cl was completely incorporated into the reactor. Then, 120 mg of catalyst Cat 1-1 was added in the same manner, and the catalyst was flushed into the reactor completely with 200 mL of n-hexane.

[0183] The polymerization reaction of ethylene was initiated by adjusting the rotation speed of the polymerization apparatus to 400 rpm, the temperature to 80 ℃, and the polymerization pressure to 10 atm. The reaction was terminated after 60 min. The obtained polymer was washed with anhydrous ethanol and dried in a vacuum oven to constant weight to obtain polyethylene. The polymer was then weighed and the polymerization activity was calculated. The polymerization results are shown in Table 1.

[0184] Experimental Example 2

[0185] This experimental example provides a method for homopolymerization of ethylene, which differs from Experimental Example 1 only in that:

[0186] Add catalyst Cat 1-2.

[0187] Experimental Example 3

[0188] This experimental example provides a method for homopolymerization of ethylene, which differs from Experimental Example 1 only in that:

[0189] Add catalyst Cat 1-3.

[0190] Test Example 4

[0191] This experimental example provides a method for homopolymerization of ethylene, which differs from Experimental Example 1 only in that:

[0192] Add catalyst Cat 1-4.

[0193] Experimental Example 5

[0194] This experimental example provides a method for homopolymerization of ethylene, which differs from Experimental Example 1 only in that:

[0195] The polymerization temperature is 100 ℃.

[0196] Experimental Example 6

[0197] This experimental example provides a method for homopolymerization of ethylene, which differs from Experimental Example 1 only in that:

[0198] The polymerization time is 10 min.

[0199] Experimental Example 7

[0200] This experimental example provides a method for homopolymerization of ethylene, which differs from Experimental Example 2 only in that:

[0201] The polymerization time is 10 min.

[0202] Experimental Example 8

[0203] This experimental example provides a method for homopolymerization of ethylene, which differs from Experimental Example 3 only in that:

[0204] The polymerization time is 10 min.

[0205] Experimental Example 9

[0206] This experimental example provides a method for homopolymerization of ethylene, which differs from Experimental Example 4 only in that:

[0207] The polymerization time is 10 min.

[0208] Comparative Test Example 1

[0209] This comparative experimental example provides a method for ethylene homopolymerization, which differs from Example 1 only in that:

[0210] Add 0.005 mmol of catalyst Cat A And 2 mL of dichloromethane solution, polymerization pressure of 10 atm;

[0211] Catalyst Cat A .

[0212] Comparative Test Example 2

[0213] This comparative example provides a method for homopolymerization of ethylene, which differs from Comparative Example 1 only in that:

[0214] Add 0.005 mmol of catalyst Cat B It has virtually no polymerization activity;

[0215] Catalyst Cat B .

[0216] Comparative Test Example 3

[0217] This comparative example provides a method for homopolymerization of ethylene, which differs from Comparative Example 1 only in that:

[0218] The polymerization time is 10 min.

[0219] Table 1 shows the test results of the polymers in the experimental and comparative experimental examples.

[0220] Table 1

[0221]

[0222] As shown in Table 1, the catalyst of this invention not only exhibits excellent thermal stability under high-temperature conditions, but also allows for stable release of catalyst activity, better suppressing polymer sticking to the reactor, and is compatible with current slurry and gas-phase processes. In contrast, the catalysts in the comparative experiments showed rapid release of polymerization activity in the early stages, and their polymerization activity decreased significantly with increasing polymerization time. They generally exhibited poor thermal stability, high polymer viscosity, hindered monomer diffusion, and burying of metal cation active centers. Furthermore, they suffered from severe polymer sticking to the reactor, making reactor cleaning difficult and severely limiting industrial applications.

Claims

1. A catalyst, characterized in that, The catalyst comprises a nickel complex, co-catalyst A, and a support; The nickel complex has the structure shown in Formula I: Equation I; In equation I, R1, R2, R3, R4, R5, R6, R7, R8, R9, R 10 Each is independently selected from H, unsubstituted, or derived from R. 11 C with substituent group 1-6 Alkyl, C 1-6 One of the alkoxy groups; R 11 Selected from unsubstituted or C 1-6 One of the alkyl groups substituted for one of the phenyl groups; Furthermore, R1, R5, R6, R 10 At least two substituents are each independently selected from unsubstituted or R 11 C with substituent group 1-6 Alkyl; R 11 Selected from unsubstituted or C 1-6 One of the alkyl groups substituted for one of the phenyl groups; Each of X is independently selected from halogens.

2. The catalyst according to claim 1, characterized in that, In equation I, R1, R2, R3, R4, R5, R6, R7, R8, R9, R 10 Each is independently selected from H, unsubstituted, or derived from R. 11 C with substituent group 1-4 Alkyl, C 1-4 One of the alkoxy groups; R 11 Selected from unsubstituted or C 1-4 One of the alkyl groups substituted for one of the phenyl groups; X is bromine and / or chlorine, each independently; Furthermore, R1, R5, R6, R 10 At least two substituents are each independently selected from unsubstituted or R 11 C with substituent group 1-4 Alkyl; R 11 Selected from unsubstituted or C 1-4 One of the alkyl groups substituted with a phenyl group.

3. The catalyst according to claim 1, characterized in that, In equation I, R1, R3, R5, R6, R8, R 10 Each is independently selected from H, unsubstituted, or derived from R. 11 Substituted methyl group, unsubstituted methyl group, or methyl group composed of R 11 Ethyl groups substituted with groups, unsubstituted ethyl groups, or ethyl groups derived from R 11 Substituted n-propyl group, unsubstituted or derived from R 11 One of the following groups: isopropyl, methoxy, ethoxy, propoxy, and isopropoxy; R 11 Selected from phenyl, and from phenyl groups substituted with one of the groups selected from methyl, ethyl, and n-propyl; Furthermore, R1, R5, R6, R 10 At least two substituents are each independently selected from unsubstituted or R 11 Substituted methyl group, unsubstituted methyl group, or methyl group composed of R 11 Ethyl groups substituted with groups, unsubstituted ethyl groups, or ethyl groups derived from R 11 Substituted n-propyl group, unsubstituted or derived from R 11 One of the isopropyl groups substituted with a functional group; R 11 Selected from phenyl, and from phenyl groups substituted with one of the groups selected from methyl, ethyl, and n-propyl; R2, R4, R7, and R9 are all H; X is all bromine.

4. The catalyst according to any one of claims 1-3, characterized in that, The nickel complex represented by Formula I has one of the following structures: 。 5. The catalyst according to claim 1, characterized in that, The cocatalyst A is selected from alkylaluminoxane A and / or alkylaluminum compound A.

6. The catalyst according to claim 5, characterized in that, The alkylaluminoxane A is selected from methylaluminoxane and / or modified methylaluminoxane; And / or, the alkylaluminum compound A is selected from one or more combinations of diethylaluminum chloride, sesquiethylaluminum chloride, ethylaluminum dichloride, trimethylaluminum, triethylaluminum, and tributylaluminum.

7. The catalyst according to claim 6, characterized in that, The alkylaluminum compound A is selected from triisobutylaluminum.

8. The catalyst according to claim 1, characterized in that, The carrier is selected from one or more of silica gel, magnesium dichloride, and aluminum oxide.

9. The catalyst according to claim 1, characterized in that, The molar ratio of the co-catalyst A, calculated as aluminum, to the nickel complex, calculated as nickel, is (50-5000):

1.

10. The catalyst according to claim 1, characterized in that, The ratio of the co-catalyst A to the support is 0.5-500 mmol / g; And / or, the ratio of the nickel complex to the support is 0.01-0.1 mmol / g.

11. A method for preparing the catalyst according to any one of claims 1-10, characterized in that, The preparation method includes the following steps: Under a protective atmosphere, the support, co-catalyst A, and solvent are mixed to obtain a dispersion. The dispersion was reacted with the nickel complex at 20-60 °C, and after post-treatment, a catalyst was obtained.

12. A method for homopolymerization of ethylene, characterized in that, The method includes: Ethylene undergoes homopolymerization in the presence of an organic solvent, a catalyst, and co-catalyst B. The catalyst is the catalyst according to any one of claims 1-10 or the catalyst prepared by the method of claim 11.

13. The method for homopolymerization of ethylene according to claim 12, characterized in that, The homopolymerization reaction is carried out at a temperature of 0-150 °C for a time of 0.1-6 h.

14. The method for homopolymerization of ethylene according to claim 12, characterized in that, The pressure of the homopolymerization reaction is 1-40 atm.

15. The method for homopolymerization of ethylene according to claim 12, characterized in that, The molar ratio of the co-catalyst B, calculated as aluminum, to the catalyst, calculated as nickel, is (50-1000):

1.

16. The method for homopolymerization of ethylene according to claim 12, characterized in that, The cocatalyst B is selected from alkylaluminoxane B and / or alkylaluminum compound B.

Images