A novel [n,o] amide nickel catalyst for ethylene and polar comonomer copolymerization and its preparation method and application

Abstract

This invention discloses a novel [N,O]amide nickel catalyst for copolymerization of ethylene and polar comonomers, its preparation method, and its application, belonging to the field of olefin polymerization technology. The [N,O]amide nickel catalyst has the following general structural formula (II): where R1, R2, R3, R4, and R7 are independently selected from C1 to C2. 20 One of the substituted phenyl, isopropyl, and alkyl groups; R5 and R6 are independently selected from hydrogen, C1 to C6, respectively. 20 The radicals are alkyl, fluorine, chlorine, bromine, iodine, nitro, hydroxyl, phenyl, or substituted phenyl; represent tetrakis(3,5-bis(trifluoromethyl)phenyl)borate anion; and those linked to Ni represent allyl. Beneficial effects: The high activity and stability of the catalysts, along with the high molecular weight of the polymer, indicate the electron-donating ability of the catalyst substrate framework to the metal center, thereby affecting the steric hindrance of the metal center and making the activity of these catalysts far higher than that of previously reported framework catalysts.

Description

Technical Field

[0001] This invention belongs to the field of olefin polymerization technology, and relates to a metal catalyst for catalyzing olefin polymerization, its preparation method and its application in catalyzing ethylene homopolymerization, and also relates to its application in ethylene / polar monomer coordination copolymerization. Background Technology

[0002] As a major producer and consumer of plastics, my country currently faces a weakness: its domestically produced polyolefins are difficult to utilize in high-end industries. The structure of the catalyst determines the structure of the polyolefin, ultimately affecting the application of polyolefin materials. Therefore, developing suitable catalysts is crucial. Since Professor Brookhart, the focus of academia and industry has shifted from the development of pre-transition metal catalysts to post-transition metal catalysts, primarily nickel and palladium. Palladium has attracted widespread attention due to its strong tolerance to external conditions, low deactivation rate, and good copolymerization effect. However, because nickel is inexpensive and has a lower chain transfer rate compared to palladium-based catalysts, it typically yields higher molecular weights. Therefore, efforts have been focused on developing highly efficient novel nickel catalysts.

[0003] In 1998, Grubbs reported a novel [N,O] catalyst (shown in chemical formula A below) that chelates a stable 6-membered ring structure by reacting a salicylaldehyde ligand with (PPh3)2PhNiC. Studies revealed that a co-catalyst (B(C6F5)3 or Ni(COD)2) is required during polymerization to pre-determine the removal of the coordinated -(PPh3)2 group; otherwise, no polymer is formed. Chen's research group synthesized a new salicylaldehyde imine nickel catalyst (shown in chemical formula B below) using aniline with its ortho-amino group substituted with a diphenylmethyl unit as one of the raw materials and investigated the effect of steric hindrance on ethylene polymerization.

[0004]

[0005] In 2018, Cai's research group designed and synthesized a class of palladium complexes with a naphthoquinone skeleton (as shown in chemical formula C above). Surprisingly, these complexes exhibited very low activity in ethylene homopolymerization, but good activity in copolymerization of ethylene with some polar norbornene compounds. Complex 1, in particular, with its sterically hindered diphenylmethyl substituent, demonstrated the most superior performance. Introducing a diphenylmethyl unit is a common strategy to enhance the thermal stability and activity of catalysts.

[0006] Another less-reported [N,O] system catalyst is the iminoformamide nickel metal complex (as shown in chemical formula D above) synthesized by the Bazan research group. They chose to modify the steric hindrance effect by changing the size of the ortho-aryl substituent on the nitrogen of the iminoformamide ligand. With increasing steric hindrance, the catalyst's activity in ethylene polymerization decreased, but the polymer molecular weight increased and the molecular weight distribution narrowed. Of particular note is that hindering axial sites leads to a significant increase in the product's molecular weight and the formation of a polymer structure with low branching.

[0007] In 2020, the Chen research group synthesized a simple yet versatile α-imine-ketone nickel system (as shown in the chemical formula E above), which has been shown to exhibit good performance in ethylene polymerization and copolymerization with polar monomers. Although these nickel catalysts are spatially open, they are thermally stable and capable of generating polymers with very high molecular weights and tunable branch densities.

[0008] Chinese patent application document CN115335419A discloses a sterically hindered phosphonamide-supported nickel(II) or palladium(II) catalyst (as shown in the above chemical formula F) for copolymerization of ethylene and polar comonomers. However, the structure of the catalyst in this patent is different from that of the present invention, and its catalytic effect and stability need to be further improved. Summary of the Invention

[0009] The technical problem to be solved by this invention is how to propose a novel [N,O]amide nickel catalyst for copolymerization of ethylene and polar comonomers, as well as its preparation method and application.

[0010] The present invention solves the above-mentioned technical problems through the following technical means:

[0011] The first aspect of the present invention provides a ligand with a general structural formula as shown in formula (Ⅰ);

[0012]

[0013] Among them, R1, R2, R3, R4, and R7 are independently selected from C1 to C2. 20 One of the substituted phenyl, isopropyl, and alkyl groups; R5 and R6 are independently selected from hydrogen, C1 to C6, respectively. 20 Hydrocarbon group, fluorine, chlorine, bromine, iodine, nitro, hydroxyl, phenyl or substituted phenyl.

[0014] Beneficial effects: This invention designs and synthesizes ligands with structures as shown in formula (I) based on the steric hindrance effect of metal centers, and uses them to prepare catalysts with structures as shown in formula (II). These catalysts are then applied to ethylene homopolymerization or ethylene / polar monomer copolymerization to reduce the degree of branching and improve the thermal stability, catalytic activity and polymer molecular weight of the catalysts.

[0015] Preferably, its structural formula is one of the following formulas (Ⅰ1), (Ⅰ2), and (Ⅰ3):

[0016]

[0017] A second aspect of the present invention provides a method for preparing the above-mentioned ligand, comprising the following steps:

[0018] (1) Add oxaloyl chloride to a toluene solution of benzoylformic acid, cool the solution, add triethylamine, stir at room temperature, and then add aniline. The solution was then stirred at room temperature, filtered, and recrystallized to obtain the intermediate ligand.

[0019] (2) Under a nitrogen atmosphere, aniline The triethylamine solution was frozen to sub-zero temperatures; then a titanium tetrachloride toluene solution was added dropwise to the mixture, and the mixture was stirred. An intermediate ligand a toluene solution was then added; the solution was stirred, heated to room temperature, and stirred; subsequently, diethyl ether was added, and the mixture was stirred; the mixture was filtered and recrystallized to obtain the product from the second step.

[0020] (3) Under N2 atmosphere, dry tetrahydrofuran was used as solvent, the product of the second step was added, and the temperature was cooled to below zero. LDA (diisopropylaminolithium) was added dropwise, and then I-R7 was added dropwise. The mixture was stirred at room temperature, and then saturated ammonium chloride solution was added. The mixture was extracted, dried, concentrated, and recrystallized to obtain the final ligand.

[0021] A third aspect of the present invention provides a [N,O]amide nickel catalyst, the general structural formula of which is shown in formula (II) below:

[0022]

[0023] Among them, R1, R2, R3, R4, and R7 are independently selected from C1 to C2. 20 One of the substituted phenyl, isopropyl, and alkyl groups; R5 and R6 are independently selected from hydrogen, C1 to C6, respectively. 20 Hydrocarbon group, fluorine, chlorine, bromine, iodine, nitro, hydroxyl, phenyl or substituted phenyl; It represents the tetrakis(3,5-bis(trifluoromethyl)phenyl)boronic acid anion; connected to Ni It represents allyl.

[0024] Preferably, its structural formula is one of the following formulas (II1), (II2), and (II3):

[0025]

[0026] A fourth aspect of the present invention provides a method for preparing the above-mentioned [N,O]amide nickel catalyst, comprising the following steps:

[0027] Under an argon or nitrogen atmosphere, the above ligand (Ⅰ) was dissolved in dichloromethane, and allyl nickel chloride and sodium tetrakis(3,5-bis(trifluoromethyl)phenyl)borate (NaBArF) were added and stirred at room temperature to obtain the [N,O]amide nickel catalyst (Ⅱ).

[0028] Preferably, the molar ratio of the ligand (Ⅰ), allyl nickel chloride, and NaBArF is 1:0.5:1.

[0029] The fifth aspect of the present invention proposes the application of the above-mentioned [N,O]amide nickel catalyst in the catalytic polymerization of olefins.

[0030] The sixth aspect of the present invention proposes the application of the above-mentioned [N,O]amide nickel catalyst in the catalytic preparation of ultra-high molecular weight polyethylene from olefins.

[0031] The advantages of this invention are:

[0032] 1. This invention designs and synthesizes a ligand with the structure shown in formula (Ⅰ) based on the steric hindrance effect of the metal center, and uses it to prepare a catalyst with the structure shown in formula (Ⅱ), and applies it to ethylene homopolymerization or ethylene / polar monomer copolymerization to reduce the degree of branching and improve the thermal stability, catalytic activity and polymer molecular weight of the catalyst.

[0033] 2. The present invention provides a catalyst having a structure of formula (II). The catalyst introduces aniline with different steric hindrance to adjust the steric hindrance of the metal center, adjust the coordination of the metal center to olefins and the insertion ability of polar monomers, improve the catalyst's catalytic activity and thermal stability for olefin polymerization, and is beneficial to improve the copolymerization activity of polar monomers and olefins and the molecular weight of polymers.

[0034] 3. The catalysts of this invention serve as coordination polymerization catalysts for ethylene homopolymerization, ethylene copolymerization, and long-chain olefins. These nickel catalysts exhibit significant performance in ethylene polymerization, including high activity (up to 1.34 × 10⁻⁶). 7 The catalyst exhibits high activity and stability, along with the high molecular weight of the polymer, indicating the ability of the catalyst substrate framework to donate electrons to the metal center. This influences the steric hindrance of the metal center, resulting in catalysts with significantly higher activity than previously reported framework catalysts. Attached Figure Description

[0035] Figure 1 The 1H NMR spectrum of ligand (Ⅰ1) in Example 1 of this invention;

[0036] Figure 2The carbon NMR spectrum of ligand (Ⅰ1) in Example 1 of this invention;

[0037] Figure 3 The 1H NMR spectrum of ligand (Ⅰ2) in Example 2 of this invention;

[0038] Figure 4 The carbon NMR spectrum of ligand (Ⅰ2) in Example 2 of this invention;

[0039] Figure 5 The 1H NMR spectrum of ligand (Ⅰ3) in Example 3 of this invention;

[0040] Figure 6 The carbon NMR spectrum of ligand (Ⅰ3) in Example 3 of this invention;

[0041] Figure 7 The above is the 1H NMR spectrum of the novel [N,O]amide nickel catalyst (Ⅱ1) of Example 4 of this invention;

[0042] Figure 8 The above is the 1H NMR spectrum of the novel [N,O]amide nickel catalyst (Ⅱ2) of Example 5 of this invention;

[0043] Figure 9 The above is the 1H NMR spectrum of the novel [N,O]amide nickel catalyst (Ⅱ3) of Example 6 of this invention;

[0044] Figure 10 This is a single-crystal structure diagram of the novel [N,O]amide nickel catalyst (Ⅱ2) of Example 5 of the present invention;

[0045] Figure 11 This is a single-crystal structure diagram of the novel [N,O]amide nickel catalyst (Ⅱ3) of Example 6 of the present invention;

[0046] Figure 12 The 1H NMR spectrum of polymer number 3 in Table 2 of Application Example 2 of this invention;

[0047] Figure 13 The 1H NMR spectrum of polymer number 4 in Table 2 of Application Example 2 of this invention;

[0048] Figure 14 The 1H NMR spectrum of polymer number 5 in Table 2 of Application Example 2 of this invention;

[0049] Figure 15 This is a graph showing the melting point Tm data of polymer number 1 in Table 1 of Application Example 1 of the present invention;

[0050] Figure 16 This is a graph showing the melting point Tm data of polymer number 2 in Table 1 of Application Example 1 of the present invention;

[0051] Figure 17This is a graph showing the melting point Tm data of polymer number 7 in Table 1 of Application Example 1 of the present invention;

[0052] Figure 18 This is a graph showing the melting point Tm data of polymer number 10 in Table 1 of Application Example 1 of the present invention;

[0053] Figure 19 This is a graph showing the melting point Tm data of polymer number 1 in Table 2 of Application Example 2 of the present invention;

[0054] Figure 20 This is a graph showing the melting point Tm data of polymer number 5 in Table 2 of Application Example 2 of the present invention;

[0055] Figure 21 This is a graph showing the melting point Tm data of polymer number 8 in Table 2 of Application Example 2 of the present invention;

[0056] Figure 22 This is a graph showing the molecular weight (Mn) data of polymer number 2 in Table 1 of Application Example 1 of the present invention;

[0057] Figure 23 This is a graph showing the molecular weight (Mn) data of polymer number 3 in Table 1 of Application Example 1 of the present invention;

[0058] Figure 24 This is a graph showing the molecular weight (Mn) data of polymer number 6 in Table 1 of Application Example 1 of the present invention;

[0059] Figure 25 This is a graph showing the molecular weight (Mn) data of polymer number 2 in Table 2 of Application Example 2 of the present invention;

[0060] Figure 26 This is a graph showing the molecular weight (Mn) data of polymer number 3 in Table 2 of Application Example 2 of the present invention;

[0061] Figure 27 This is a graph showing the molecular weight (Mn) data of polymer number 6 in Table 2 of Application Example 2 of the present invention;

[0062] Figure 28 The graph shows the molecular weight (Mn) data of polymer number 7 in Table 2 of Application Example 2 of the present invention. Detailed Implementation

[0063] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0064] This invention provides a method for synthesizing a ligand having the structure of formula (Ⅰ);

[0065]

[0066] Among them, R1, R2, R3, R4, and R7 can be independently selected from C1 to C2. 20 One of the substituted phenyl, isopropyl, and alkyl groups; R5 and R6 can be independently selected from hydrogen, C1 to C6, respectively. 20 Hydrocarbon group, fluorine, chlorine, bromine, iodine, nitro, hydroxyl, C1-C 20 The substituted hydrocarbon group, phenyl or substituted phenyl group.

[0067] The synthesis method includes the following steps:

[0068] (1) Add oxaloyl chloride to a toluene solution of benzoylformic acid, cool the solution, add triethylamine, stir at room temperature, and then add aniline. Add triethylamine; then stir the solution at room temperature, filter, and recrystallize to obtain the intermediate ligand.

[0069] (2) Under a nitrogen atmosphere, aniline The triethylamine solution in toluene was frozen to sub-zero temperatures; then a titanium tetrachloride toluene solution was added dropwise to the mixture, and the mixture was stirred. The intermediate ligand a toluene solution was then added, stirred, heated to room temperature, and stirred again. Subsequently, diethyl ether was added, and the mixture was stirred. The mixture was filtered and recrystallized to obtain the product from the second step.

[0070] (3) Under N2 atmosphere, using dry tetrahydrofuran as solvent, the product from the second step was added and cooled to sub-zero temperature. LDA was added dropwise, and then I-R7 was added dropwise. The mixture was stirred at room temperature, and then a saturated ammonium chloride solution was added. The mixture was extracted, dried, concentrated, and recrystallized to obtain the final ligand, the structure of which is shown in formula (I):

[0071]

[0072] Specifically, ligands with the structure of formula (Ⅰ) can be one of the following structures: formula (Ⅰ1), formula (Ⅰ2), or formula (Ⅰ3);

[0073]

[0074] This invention also provides a method for preparing a novel [N,O]amide nickel catalyst, which has the structure of formula (II);

[0075]

[0076] Among them, R1, R2, R3, R4, and R7 can be independently selected from C1 to C2. 20One of the substituted phenyl, isopropyl, and alkyl groups; R5 and R6 can be independently selected from hydrogen, C1 to C6, respectively. 20 Hydrocarbon group, fluorine, chlorine, bromine, iodine, nitro, hydroxyl, C1-C 20 The substituted hydrocarbon group, phenyl or substituted phenyl group.

[0077] The preparation method includes the following steps:

[0078] Under an argon or nitrogen atmosphere, the above ligand (Ⅰ) was dissolved in dichloromethane, and allyl nickel chloride and sodium tetrakis(3,5-bis(trifluoromethyl)phenyl)borate (NaBArF) were added and stirred at room temperature to obtain the [N,O]amide nickel complex, the structure of which is shown in formula (Ⅱ): The molar ratio of ligand (Ⅰ), allyl nickel chloride, and NaBArF is 1:0.5:1.

[0079] Specifically, the [N,O]amide nickel catalyst having the structure of formula (II) can be the following structures: formula (II1), formula (II2), and formula (II3):

[0080]

[0081] This invention also provides the application of a [N,O]amide nickel catalyst with formula (II) in the catalytic polymerization of olefins, including its use in catalyzing homopolymerization of olefins or copolymerization of olefins with polar monomers; wherein the olefins include ethylene, α-olefins, etc., and α-olefins refer to C3~C4 olefins. 18 The terminal olefin can be, for example, one or a mixture of propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 4-methyl-1-pentene, 1-decene, 1-dodecene, and 1-octadecene; the polar monomer can be a C2-C2 group containing a polar group. 20 1-olefin derivatives and cyclic olefin derivatives containing polar groups, wherein the polar groups are organic functional groups containing oxygen, nitrogen, sulfur, or selenium, including hydroxyl, carboxyl, ester, alkoxy, amino, amide, thioether, silyl ether, or selenium ether. Furthermore, the polymerization can be carried out using slurry polymerization, loop polymerization, gas-phase polymerization, or other forms of polymerization processes.

[0082] The organic solvent used in the polymerization reaction is a hydrocarbon, cyclic hydrocarbon or aromatic hydrocarbon. To facilitate reactor operation and polymerization products, the organic solvent can be a hydrocarbon with fewer than 12 carbon atoms, which can be one or more of hexane, toluene and chlorobenzene.

[0083] The polymerization temperature of the polymerization reaction is 0 to 160°C, for example, 40°C; the polymerization pressure of the olefin is 0.1 to 50 MPa.

[0084] This invention also provides an application of a [N,O]amide nickel catalyst with the structure of formula (II) in the catalytic preparation of ultra-high molecular weight polyethylene from olefins, wherein the polymerization is carried out using a gas-phase polymerization process.

[0085] To further understand the present invention, the catalyst provided by the present invention will be described in detail below with reference to the embodiments. The scope of protection of the present invention is not limited by the following embodiments.

[0086] The following examples illustrate the specific content of the present invention. The data provided include the synthesis of ligands, the synthesis of catalysts, and methods for ethylene polymerization or copolymerization. The catalyst synthesis and polymerization processes are carried out under anhydrous and oxygen-free conditions. All sensitive substances are stored in a glove box, all solvents are rigorously dried and dehydrated, ethylene gas is purified using a dehydration and deoxygenation column, and monomers such as norbornene are purified by dehydration, deoxygenation, and vacuum distillation. Unless otherwise specified, all raw materials are commercially available.

[0087] NMR was performed using a Bruker 400MHz NMR instrument; elemental analysis was conducted by the Physics and Chemistry Center of the University of Science and Technology of China; molecular weight and molecular weight distribution were determined by GPC (polystyrene columns, HR2 and HR4, oven temperature 150℃, using Water 1515 and Water 2414 pumps; mobile phase was trichlorobenzene, flow rate 1.0 mL / min, using polydisperse polystyrene as the standard); mass spectrometry was performed using a Thermo LTQ Orbitrap XL (ESI+) or P-SIMS-Gly of Bruker Daltonics Inc (EI+); single-crystal X-ray diffraction analysis was performed using an Oxford Diffraction Gemini S Ultra CCD single-crystal diffractometer, Cu Kα. Room temperature radiation.

[0088] Example 1:

[0089] Preparation of ligands with the structure of formula (Ⅰ1):

[0090]

[0091] Includes the following steps:

[0092] (1) Add oxaloyl chloride (13.5 mmol) to a toluene solution (200 mL) of benzoylformic acid (13.3 mmol); cool the solution to 0 °C and add triethylamine (13.3 mmol); stir the solution at room temperature for 2 hours, and then add aniline. (where R3 is CHPh2, R4 is CHPh2, and R6 is Me) (13.3 mmol) and triethylamine (13.3 mmol); the solution was stirred overnight at room temperature and then filtered with diatomaceous earth; volatiles were removed under vacuum, and the intermediate ligand was recrystallized from hexane at -20 °C.

[0093] (2) Under a nitrogen atmosphere, aniline (R1 is) i Pr and R2 are i A solution of Pr, R5 (H) (3.23 mmol) and triethylamine (29.1 mmol) in toluene (90 mL) was frozen to -35 °C; then a titanium tetrachloride toluene solution (3.55 mL; 1 mol / L) was slowly added dropwise to the mixed solution to obtain a dark red solution, which was then stirred for 10 minutes; immediately, a toluene solution of the intermediate ligand obtained in step (1) was added; the solution was stirred vigorously, heated to room temperature, and stirred overnight; subsequently, 250 mL of diethyl ether was added, and the resulting suspension was stirred overnight in the open air. The suspension was filtered through diatomaceous earth to remove the solvent, and hexane was added for recrystallization at -20 °C to obtain the product of the second step;

[0094] (3) Under N2 atmosphere, using 50 ml of dry tetrahydrofuran as solvent, add the product of the second step (1 eq, 5 mmol) and cool to -78℃. Slowly add LDA (1.5 eq, 3.75 ml, 7.5 mmol) and stir for 1 h. Then add I-Me (1.5 eq, 1.06 g, 7.5 mmol) and stir at room temperature for 2 h. Add saturated ammonium chloride solution and extract with ethyl acetate (3 x 10 ml). Dry with anhydrous sodium sulfate and concentrate. Recrystallize with n-hexane to obtain a yellow powder, which is the final ligand.

[0095]

[0096] Its nuclear magnetic resonance hydrogen spectrum and carbon spectrum are as follows Figure 1 , Figure 2 As shown, the specific data is as follows:

[0097] 1 H NMR (400MHz, CDCl3) δ7.38–7.24(m,7H,Ph-H),7.22–7.07(m,21H,Ph-H),6.79(s,2H,Ph-H),5.89(s,2H,CHPh2),2.98(h,J=7.1Hz,2H, i Pr-CH),2.53(s,3H,N-CH3),2.19(d,J=6.0Hz,3H,Ph-CH3),1.11(d,J=6.8Hz,6H, iPr-CH3),0.85(d,J=7.0Hz,6H, i Pr-CH3).

[0098] 13 C NMR(151MHz,CHLOROFORM-D)δ168.38,163.21(carbonyl and imine),144.67,144.56,142.87,141.57,137.59,136.99,135.94,132.14,131.04,130.80,130.61,129.79,129.66,129.42,128.97,128. 90,128.69,128.51,128.31,128.01,126.51,126.28,124.43,123.92,123.58(Ph-C),52.04,51.15(CHPh2),38.49(N-CH3),28.30,27.74( i Pr-CH),24.76,23.98,23.79,22.68( i Pr-CH3), 21.83(Ph-CH3).

[0099] Example 2:

[0100] Preparation of ligands with the structure of formula (Ⅰ2):

[0101]

[0102] The preparation method is the same as in Example 1, except that: aniline in step (1) Where R3 is i Pr, R4 are i Pr and R6 are H; aniline in step (2) Where R1 is i Pr and R2 are i Pr and R5 are H.

[0103] Its nuclear magnetic resonance hydrogen spectrum and carbon spectrum are as follows Figure 3 , Figure 4 As shown, the specific data is as follows:

[0104] 1 H NMR (400MHz, CDCl3) δ7.16 (d, J=4.3Hz, 3H, Ph-H), 7.01–6.93 (m, 8H, Ph-H), 4.56 (d, J=7.3Hz, 2H, i Pr-CH),3.17–2.99(m,3H,N-CH3),2.31(s,2H, iPr-CH), 1.28 (d, J = 11.4 Hz, 12H, i Pr-CH3), 0.94–0.83 (m, 12H, i Pr-CH3).

[0105] 13 C NMR(151MHz,CHLOROFORM-D)δ166.43,145.10,135.44,134.88,131.53,130.55,130.01,128.8 7,128.04,124.64,124.44,123.76,123.55(Ph-C),38.25(N-CH3),28.94,28.91,28.90,28.89( i Pr-CH),28.51,27.42,26.13,24.53,24.18,23.26,22.88,21.00( i Pr-CH3).

[0106] Example 3:

[0107] Preparation of ligands with the structure of formula (Ⅰ3)

[0108]

[0109] The preparation method is the same as in Example 1, except that: aniline in step (1) Where R3 is Me, R4 is Me, and R6 is H; aniline in step (2) Where R1 is i Pr and R2 are i Pr and R5 are H.

[0110] Its nuclear magnetic resonance hydrogen spectrum and carbon spectrum are as follows Figure 5 , Figure 6 As shown, the specific data is as follows:

[0111] 1 H NMR (400MHz, CDCl3) δ7.48 (d, J=6.9Hz, 1H, Ph-H), 7.07 (ddd, J=29.2, 13.6, 7.5Hz, 5H, Ph-H), 6 .94(t,J=7.5Hz,4H,Ph-H),6.83–6.78(m,3H,Ph-H),3.22(s,3H,N-CH3),2.27(p,J=6.9Hz,2H, i Pr-CH),1.92(s,6H,Ph-CH3),0.96(d,J=6.7Hz,6H, i Pr-CH3), 0.61 (d, J = 6.8 Hz, 6H,i Pr-CH3).

[0112] 13 C NMR(151MHz,CHLOROFORM-D)δ167.63,164.46,144.27,139.41,137.46,136.36,132.96,131.51,129.84,129.01,128 .81,128.72,128.59,128.55,128.15,128.03,127.88,124.57,123.91,122.98(Ph-C),36.02(N-CH3),34.65,29.79( i Pr-CH),27.44,24.66,24.60,22.20( i Pr-CH3), 21.12, 17.88 (Ph-CH3).

[0113] Example 4:

[0114] Preparation of a novel [N,O]amide nickel catalyst with the structure of formula (Ⅱ1):

[0115]

[0116] The preparation method includes the following steps:

[0117] Under an argon or nitrogen atmosphere, the ligand (Ⅰ1) obtained in Example 1 was mixed with a nickel compound (allyl nickel chloride) and sodium tetrakis(3,5-bis(trifluoromethyl)phenyl)borate (NaBArF) in a molar ratio of 1:0.5:1. After adding dichloromethane, the mixture was stirred at room temperature for 20-24 hours. The resulting mixture was then filtered on diatomaceous earth and evaporated to obtain a blackish-red solid, which is the novel [N,O]amide nickel complex (Ⅱ1).

[0118] Its 1H NMR spectrum is as follows Figure 7 As shown.

[0119] Example 5:

[0120] Preparation of a novel [N,O]amide nickel catalyst with the structure of formula (Ⅱ2):

[0121]

[0122] The preparation method is the same as in Example 4, except that the ligand (Ⅰ2) obtained in Example 2 is used.

[0123] Its 1H NMR spectrum is as follows Figure 8 As shown in Figure 10, its single-crystal structure is also shown.

[0124]

[0125]

[0126] Molecular structure of II2 Hydrogen atoms and BArF molecule have beenomitted for clarity.Selected bond lengths and angles(°):Ni1-O1 1.900(4),Ni1-N1 1.906(4),Ni1-C13 1.966(7),Ni1-C16 1.969(6),Ni1-C14 1.971(14),Ni1-C171.956(14),O1-C18 1.248(6),N1-C19 1.442(7),N1-C19 1.293(6),N2-C18 1.335(6),N2-C27 1.447(6),N2-C26 1.473(7),O1-Ni1-N1 81.59(17),O1-Ni1-C13 174.0(3),O1-Ni1-C16 101.6(2),O1-Ni1-C14 137.4(5),O1-Ni1-C17 138,2(5),N1-Ni1-C13 104.4(3),N1-Ni1-C16 173.2(2),N1-Ni1-C14 138.1(5),N1-Ni1-C17 133.4(5).

[0127] Example 6:

[0128] Preparation of a novel [N,O]amide nickel catalyst (I3) with the structure of formula (Ⅱ3):

[0129]

[0130] The preparation method is the same as in Example 4, except that the ligand (Ⅰ3) obtained in Example 3 is used.

[0131] Its 1H NMR spectrum is as follows Figure 9 As shown in Figure 11, its single-crystal structure is also shown.

[0132]

[0133]

[0134] Molecular structure of II3 Hydrogen atoms and BArF molecule have beenomitted for clarity.Selected bond lengths and angles(°):Ni1-O1 1.938(2),Ni1-N2 1.927(2),Ni1-C4 1.971(3),Ni1-C3 1.996(3),Ni1-C1 2.002(5),Ni1-C2 1.980(7),O1-C33 1.261(3),N2-C5 1.456(3),N2-C17 1.295(3),N1-C33 1.316(4),N1-C241.448(3),N1-C32 1.473(4),O1-Ni1-C4 171.21(10),O1-Ni1-C3 97.96(11),O1-Ni1-C1132.88(16),O1-Ni1-C2 130.6(2).

[0135] Application Example 1:

[0136] Ethylene polymerization was carried out using the catalysts prepared in Examples 4-6, and the specific polymerization methods are as follows:

[0137] In a glove box under a nitrogen atmosphere, 30 mL of toluene was added to a 50 mL autoclave (equipped with a stirrer, heating device, and thermometer). The container was then connected to a high-pressure pipeline, and the pipeline was evacuated. The container temperature was set to the desired temperature and maintained for 5 minutes. The 0.5 μmol catalyst prepared in Examples 4-6 was dissolved in 2 mL of dichloromethane and injected into the autoclave using a syringe. Then, the ethylene valve was opened, ethylene was introduced into the autoclave, and the ethylene pressure was adjusted to 8 atm. The reaction was allowed to proceed for 5 minutes. After that, the reaction was stopped, the autoclave was opened, ethanol was added to precipitate the solid, the mixture was filtered under reduced pressure, and dried in a vacuum drying oven to obtain a white solid.

[0138] The results of ethylene polymerization catalyzed by the catalysts prepared in Examples 4-6 are shown in Table 1 below:

[0139] Table 1. Catalysts for Ethylene Polymerization a

[0140]

[0141] in, a Polymerization conditions: catalyst 0.5 μmol, toluene = 28 mL, dichloromethane = 2 mL, ethylene = 8 atm, time = 5 minutes; b Activity=107 g·mol -1 ·h -1 ; c Melting point was determined using a differential scanning calorimeter. d Weight-average molecular weight = 10 4 gmol -1 The molecular weight was determined by GPC using polystyrene as the standard and trichlorobenzene as the solvent at 150°C.

[0142] As shown in Table 1, the catalyst in this application can catalyze the homopolymerization of ethylene to prepare polyethylene under certain conditions, with the highest activity reaching 3.21 × 10⁻⁶. 7 g·mol -1 ·h -1 Melting point: 119–132℃; Number average molecular weight: 113 × 10⁻⁶ 4 g / mol.

[0143] Application Example 2:

[0144] The catalysts prepared in Examples 4-6 were used to carry out the copolymerization reaction of ethylene with polar monomers. The specific polymerization methods are as follows:

[0145] In a glove box under a nitrogen atmosphere, 20 mL of toluene and a polar monomer (methyl 10-undecenoate) were added to a 50 mL autoclave (equipped with a stirrer, heating device, and thermometer). The container was then connected to a high-pressure pipeline and evacuated. The container temperature was set to 80°C and maintained for 5 minutes. Then, 20 μmol of the catalyst prepared in Examples 4-6 was dissolved in 2 mL of dichloromethane and injected into the autoclave using a syringe. The ethylene valve was then opened, and ethylene was introduced into the autoclave. The ethylene pressure was adjusted to 8 atm, and the reaction was allowed to proceed for two hours. The reaction was then stopped, the autoclave was opened, and ethanol was added to precipitate the solid. The mixture was filtered under reduced pressure and dried in a vacuum drying oven to obtain a white solid.

[0146] The results of the polymerization of ethylene with polar monomers catalyzed by the catalysts prepared in Examples 4-6 are shown in Table 2 below:

[0147] Table 2. Catalysts for copolymerization of ethylene and polar monomers a

[0148]

[0149]

[0150] in, a Polymerization conditions: catalyst 20 μmol, toluene = 20 mL, dichloromethane = 2 mL, ethylene = 8 atm, time = 2 hours, polymerization temperature 80 degrees Celsius; b Activity=105 g·mol -1 ·h -1 ; c The polar monomer insertion ratio was measured by 1H NMR spectroscopy; d Melting point was determined using a differential scanning calorimeter. e Weight-average molecular weight = 10 4 g mol -1 The molecular weight was determined by GPC using polystyrene as the standard and trichlorobenzene as the solvent at 150°C.

[0151] As shown in Table 2, the catalyst in this application can catalyze the copolymerization of ethylene with polar monomers to prepare polar polyolefins under certain conditions, with the highest activity reaching 6.6 × 10⁻⁶. 5 g·mol -1 ·h -1 The insertion rate is as high as 5.2%; the weight-average molecular weight is as high as 3.1 × 10⁻⁶. 4 g / mol.

[0152] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A [N,O]amide nickel catalyst, characterized in that, Its structural formula is one of the following formulas (II1), (II2), and (II3): （Ⅱ1）、 （Ⅱ2）、 （Ⅱ3）。 2. The method for preparing the [N,O]amide nickel catalyst according to claim 1, characterized in that, Includes the following steps: Under an argon or nitrogen atmosphere, the ligand was dissolved in dichloromethane, and allyl nickel chloride and sodium tetrakis(3,5-bis(trifluoromethyl)phenyl)borate were added and stirred at room temperature to obtain the [N,O]amide nickel catalyst. The ligand has a structural formula of one of the following formulas (Ⅰ1), (Ⅰ2), and (Ⅰ3): （Ⅰ1）、 （Ⅰ2）、 （Ⅰ3）。 3. The preparation method according to claim 2, characterized in that, The molar ratio of the ligand, allyl nickel chloride, and sodium tetrakis(3,5-bis(trifluoromethyl)phenyl)borate is 1:0.5:

1.

4. The preparation method according to claim 2, characterized in that, The structural formula of the ligand is: (Ⅰ1).

5. The application of the [N,O]amide nickel catalyst according to claim 1 in the catalytic polymerization of olefins.

6. The application of the [N,O]amide nickel catalyst according to claim 1 in the catalytic preparation of ultra-high molecular weight polyethylene from olefins.

7. The application according to claim 6, characterized in that, The catalyst dosage is 1~20μmol / L, the polymerization pressure is 0.1~50MPa, the reaction temperature is controlled at 0~200℃, and the reaction time is 0.05~5.00 hours.

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