Alpha-diimine nickel complex catalyst, method of making and use thereof

Abstract

The application provides an alpha-diamino nickel complex for catalytically preparing polyethylene, realizes control of polymer molecular weight and branching degree by regulating N-aryl ortho groups in the alpha-diamino nickel complex molecules and polymerization conditions, and has the advantages of high catalytic activity, low cost, stable performance and the like. The prepared polyethylene has high molecular weight, narrow molecular weight distribution, high branching degree and excellent mechanical mechanical performance.

Description

Technical Field

[0001] This invention belongs to the field of olefin catalytic polymerization technology, specifically relating to an α-diimine nickel complex catalyst and its preparation method, and further relating to a method for catalytically preparing branched polyethylene using the α-diimine nickel complex catalyst. Background Technology

[0002] Polyethylene is currently the fastest-growing, highest-volume, and most widely used synthetic resin, with applications in many fields including industry, agriculture, military, medical and health, and daily life. The widespread development and application of polyethylene products is inseparable from the development of olefin polymerization catalysts. Currently, industrially available polyethylene catalysts mainly include Ziegler-Natta type catalysts (DEPat 889229 (1953); IT Pat 536899 (1955) and IT Pat 545332 (1956); Chem. Rev., 2000, 100, 1169 and related literature in this special issue), Phillips type catalysts (Belg. Pat. 530617 (1955); Chem. Rev. 1996, 96, 3327), and metallocene catalysts (W. Kaminsky, Metalorganic Catalysts for Synthesis and Polymerization, Berlin: Springer, 1999), as well as high-efficiency ethylene oligomerization and polymerization catalysts of the post-transition metal complex type developed in recent years.

[0003] In 1995, Brookhar and his colleagues introduced cationic α-diimine complexes of Ni(II) and Pd(II), containing a large number of aryl substituents (Formula 1, Formula 2), which were of milestone significance as important catalysts for the polymerization of ethylene, α-olefins and some functional polar olefins (J. Am. Chem. Soc., 1995, 117, 6414). However, the classic Brookhar-type α-diimine nickel complexes have insufficient stability at industrially relevant temperatures (80-100 °C). Subsequently, a great deal of research was conducted on improving the thermal stability of α-diimine nickel catalysts and the direct synthesis of branched elastomer materials from the homopolymerization of ethylene.

[0004]

[0005] Our research group has been dedicated to the design and development of olefin polymerization catalysts and the exploration of catalytic processes, focusing on post-transition metal catalysts and ligands such as N^N, N^N^N, and N^O. Among these, the 4,5-diazafluorene-9-one benzoylhydrazone nickel complex demonstrated good catalytic activity for ethylene oligomerization and polymerization (Applied Catalysis A: General. 2003, 246, 11). Subsequently, we designed and synthesized mononuclear and dinuclear pyridineimine nickel complexes and catalyzed ethylene polymerization, obtaining branched polyethylene. NMR studies confirmed that the branched chain was butyl (J. Organomet. Chem. 2005, 690, 1570 and J. Organomet. Chem. 2005, 690, 1739). Furthermore, our research group also designed and synthesized a 2-benzimidazole-1,10-phenanthroline nickel complex, which achieved an activity of 1.27 × 10⁻⁶ for ethylene oligomerization. 7 g·mol -1 ·h -1 (Eur. J. Inorg. Chem. 2007, 3816) The activity of this catalyst in ethylene polymerization is significantly higher than that of other general-purpose complex catalysts, but it cannot be used to prepare high-molecular-weight, highly branched polyethylene elastomer materials. In recent years, the inventors have modified the α-diimine nickel complex with large steric hindrance (as shown in Equation 3). This type of catalyst exhibits the highest activity at the ethylene polymerization temperature of 40°C and has better thermal stability, but its catalytic activity is still relatively low (2.68 × 10⁻⁶). 6 g·mol -1 ·h -1 Furthermore, the polyethylene molecular weight produced at higher operating temperatures is too low to guarantee any useful applications.

[0006]

[0007] Transition metal complexes, as novel catalysts for olefin polymerization, still face challenges in basic research and constraints in industrialization. Developing catalysts with good thermal stability and high activity to catalyze olefin polymerization and prepare branched polyethylene with high branching degree, high molecular weight, narrow molecular weight distribution, and good mechanical properties remains an urgent problem to be solved. Summary of the Invention

[0008] To address the aforementioned problems, this invention provides an α-diimine nickel complex as an olefin polymerization catalyst. This complex possesses a single catalytic active center, and its molecular weight and degree of branching can be controlled by adjusting the N-aryl ortho-groups in the α-diimine nickel complex molecule and the polymerization conditions. Its catalytic activity can reach 1.0 × 10⁻⁶. 7 g·mol -1 (Ni)·h-1 The prepared polyethylene had a weight-average molecular weight (Mw) ranging from 1.0 to 15.19 × 10⁻⁶. 5 g·mol -1 The molecular weight distribution is between 1.9 and 3.12, with a high degree of branching, reaching 86-102 branches per 1000 carbon atoms. It also has good mechanical properties, with a tensile strength of up to 10.06 MPa and an elongation at break of up to 366%, and has great potential for industrial applications, thus completing this invention.

[0009] The first aspect of this invention aims to provide an α-diimine nickel complex for the catalytic preparation of polyethylene, having the following structure:

[0010]

[0011] R1 and R2 are each independently selected from hydrogen, alkyl, alkoxy, aryloxy or arylmethyl, preferably from alkyl or substituted phenylmethyl with C1-C6 carbon atoms, more preferably from methyl, ethyl, isopropyl or di(p-fluorophenyl)methyl; X is selected from F, Cl, Br, such as Br.

[0012] A second aspect of the present invention aims to provide a method for preparing the α-diimine nickel complex, wherein the method comprises using α-diimine ligands and nickel halide as raw materials, reacting and coordinating in a solvent to prepare the α-diimine nickel complex.

[0013] The α-diimine ligand is obtained by reacting 2,3-butanedione, substituted aniline, and a water-soluble zinc salt under acid catalysis to form an α-diimine zinc complex. The α-diimine ligand is then reacted under alkaline conditions to yield the α-diimine ligand, specifically through the following steps:

[0014] Step 1: Add 2,3-butanedione, substituted aniline and water-soluble zinc salt to an organic acid, stir and react to obtain α-diimine zinc complex;

[0015] Step 2: Add the α-diimine zinc complex to solvent I, then add an aqueous carbonate solution, stir the reaction to obtain the reaction solution;

[0016] Step 3: Post-process the reaction solution to obtain α-diimine ligands.

[0017] A third aspect of this invention aims to provide the use of the α-diimine nickel complex as a master catalyst for catalyzing the polymerization of olefins, preferably for catalyzing the polymerization of ethylene to prepare branched polyethylene. The polymerization reaction further includes a co-catalyst selected from one or more of aluminoxanes, alkylaluminum, and alkylaluminum chlorides.

[0018] The fourth aspect of this invention aims to provide a method for preparing branched polyethylene, wherein ethylene gas is passed into solvent II containing a main catalyst α-diimine nickel complex and a co-catalyst, the ethylene pressure is kept constant, and polymerization is carried out by stirring to prepare branched polyethylene.

[0019] The α-diimine nickel complex catalyst and polyethylene synthesis method provided by this invention have the following beneficial effects:

[0020] (1) The α-diimine nickel complex provided by the present invention has a single catalytic active center as an olefin polymerization catalyst. The molecular weight and branching degree of the polymer can be controlled by adjusting the N-aryl ortho-group in the α-diimine nickel complex molecule and the polymerization conditions. It also has the advantages of high catalytic activity, low cost and stable performance.

[0021] (2) The method for preparing the α-diimine nickel complex provided by the present invention has the advantages of mild reaction conditions, short cycle and simple operation conditions.

[0022] (3) The α-diimine nickel complex provided by this invention exhibits excellent catalytic activity when used in the ethylene polymerization reaction. In ethylene polymerization, the α-diimine nickel complex provided by this invention achieves an activity of 1.0 × 10⁻⁶ nickel complex catalyzing ethylene polymerization at room temperature. 7 g·mol -1 (Ni)·h -1 The weight-average molecular weight (Mw) of the prepared polyethylene ranged from 1.0 to 15.19 × 10⁻⁶. 5 g·mol -1 The values ​​fluctuate between 1.9 and 3.12, with the molecular weight distribution ranging from 1.9 to 3.12.

[0023] (4) Under high temperature conditions, the α-diimine nickel complex provided by the invention still exhibits high activity in catalyzing ethylene polymerization, demonstrating excellent heat resistance and stability. The resulting polyethylene has a high degree of branching, reaching 86-102 branches per 1000 carbon atoms, and also possesses good mechanical properties, with a tensile strength of up to 10.06 MPa and an elongation at break of up to 366%. The resulting polyethylene has great potential for industrial application. Attached Figure Description

[0024] Figure 1 The nuclear magnetic resonance spectrum of the polyethylene prepared in Example 17 of the present invention is shown;

[0025] Figure 2 The nuclear magnetic resonance spectrum of the polyethylene prepared in Example 56 of the present invention is shown;

[0026] Figure 3 The nuclear magnetic resonance spectrum of the polyethylene prepared in Example 58 of the present invention is shown;

[0027] Figure 4 The nuclear magnetic resonance spectrum of the polyethylene prepared in Example 59 of the present invention is shown.

[0028] Figure 5 The tensile stress-strain tests of polyethylene prepared in Examples 34-35 and 56-59 of the present invention are shown. Detailed Implementation

[0029] The present invention will now be described in detail through specific embodiments, and the features and advantages of the present invention will become clearer and more explicit with these descriptions.

[0030] This invention provides an α-diimine nickel complex for the catalytic preparation of polyethylene. This complex, as a catalyst, possesses a single catalytic active center. The molecular weight and branching degree of the polymer can be controlled by adjusting the N-aryl ortho-groups in the α-diimine nickel complex molecule and the polymerization conditions. It also exhibits advantages such as high catalytic activity, low cost, and stable performance. Using this catalyst to catalyze the polymerization of ethylene can produce polyethylene with high molecular weight, narrow molecular weight distribution, high branching degree, and excellent mechanical properties.

[0031] This invention provides an α-diimine nickel complex for the catalytic preparation of polyethylene, having the following structure:

[0032]

[0033] R1 and R2 are each independently selected from hydrogen, alkyl, alkoxy, aryloxy or arylmethyl, preferably from alkyl or substituted phenylmethyl with C1-C6 carbon atoms, more preferably from methyl, ethyl, isopropyl or di(p-fluorophenyl)methyl; X is selected from F, Cl, Br, preferably Cl or Br, such as Br.

[0034] Preferably, the α-diimine nickel complex is selected from the following complexes:

[0035] X is selected from F, Cl or Br, preferably Cl or Br, such as Br.

[0036] The α-diimine nickel complex provided by this invention, as an olefin polymerization catalyst, has a single catalytic active center. The molecular weight and branching degree of the polymer can be controlled by regulating the N-aryl ortho-group in the α-diimine nickel complex molecule. It also has the advantages of high catalytic activity, low cost, and stable performance.

[0037] The present invention also provides a method for preparing the α-diimine nickel complex, wherein the method comprises α-diimine ligands and nickel halide as raw materials, reacting and coordinating in a solvent to prepare the α-diimine nickel complex.

[0038] The nickel halide is selected from NiF, NiCl, or NiBr, preferably NiCl or NiBr, such as NiBr. The molar ratio of the α-diimine ligand to the nickel halide is (0.15-0.3):0.15, preferably (0.15-0.25):0.15, and more preferably (0.15-0.2):0.15.

[0039] The solvent is selected from one or more of ether solvents, halocarbon solvents, or alcohol solvents, preferably one or more of tetrahydrofuran, dichloromethane, or ethanol, and more preferably tetrahydrofuran. The molar volume ratio of the nickel halide to the solvent is 0.15 mmol:(1-8) mL, preferably 0.15 mmol:(2-6) mL, more preferably 0.15 mmol:(4-6) mL, such as 0.15 mmol:5 mL.

[0040] The reaction is carried out under a protective atmosphere, such as argon or nitrogen, at a temperature of 15-30°C, preferably 20-25°C, for a reaction time of 8-18 hours, preferably 12-14 hours.

[0041] The α-diimine ligand has the following structure:

[0042]

[0043] R1 and R2 are each independently selected from hydrogen, alkyl, alkoxy, aryloxy or arylmethyl, preferably from alkyl or substituted phenylmethyl with a carbon number of C1-C6, and more preferably from methyl, ethyl, isopropyl or di(p-fluorophenyl)methyl.

[0044] The α-diimine ligand is obtained by reacting 2,3-butanedione, substituted aniline, and a water-soluble zinc salt under acid catalysis to form an α-diimine zinc complex. The α-diimine ligand is then reacted under alkaline conditions to yield the α-diimine ligand, specifically through the following steps:

[0045] Step 1: Add 2,3-butanedione, substituted aniline and water-soluble zinc salt to an organic acid, stir and react to obtain α-diimine zinc complex;

[0046] The substituted aniline is selected from amine compounds having the following structures:

[0047]

[0048] R1 and R2 are each independently selected from hydrogen, alkyl, alkoxy, aryloxy or arylmethyl, preferably from alkyl or substituted phenylmethyl with a carbon number of C1-C6, and more preferably from methyl, ethyl, isopropyl or di(p-fluorophenyl)methyl.

[0049] The molar ratio of 2,3-butanedione to substituted aniline is 1:(2-3.4), preferably 1:(2-2.8), and more preferably 1:(2-2.2).

[0050] The molar ratio of the 2,3-butanedione to the water-soluble zinc salt is 1:(1-2.4), preferably 1:(1-1.8), and more preferably 1:(1-1.2).

[0051] The organic acid is selected from carboxylic acids, preferably one or more of formic acid, acetic acid, oxalic acid or succinic acid, and more preferably acetic acid. The molar volume ratio of the 2,3-butanedione to the organic acid is 3 mmol:(1-7) mL, preferably 3 mmol:(1.5-5) mL, and more preferably 3 mmol:(2-3) mL.

[0052] The reaction temperature is 60-100℃, preferably 75-85℃, and the reaction time is 2-6h, preferably 4-5h.

[0053] After the reaction was completed, the reaction solution was cooled to room temperature, and diethyl ether was added to the reaction solution to precipitate the product. The product was then filtered to obtain the α-diimine zinc complex.

[0054] Step 2: Add the α-diimine zinc complex to solvent I, then add an aqueous carbonate solution, stir the reaction to obtain the reaction solution;

[0055] Solvent I is selected from one or more of haloalkane solvents, preferably one or more of chloromethane, dichloromethane, dichloroethane or trichloromethane, and more preferably dichloromethane.

[0056] The stirring reaction is carried out at 15-30°C, preferably 20-25°C, for 1-3 hours, preferably 1.5-2 hours.

[0057] Step 3: Post-process the reaction solution to obtain α-diimine ligands.

[0058] After the stirring reaction was completed, the mixture was allowed to stand, the organic layer was separated, washed with water, dried with a solid desiccant, and the solvent was removed by rotary evaporation. After recrystallization, the α-diimine ligand was obtained.

[0059] The present invention also provides the use of the α-diimine nickel complex as a main catalyst for catalyzing olefin polymerization, preferably for catalyzing ethylene polymerization to prepare branched polyethylene. The polymerization reaction further includes a co-catalyst selected from one or more of aluminoxanes, alkylaluminum, and alkylaluminum chlorides.

[0060] The aluminum oxane is selected from one or both of methylaluminoxane (MAO) or triisobutylaluminum-modified methylaluminoxane (MMAO), more preferably MAO.

[0061] Alkyl aluminum chloride is selected from one or more of diethylaluminum chloride (Et2AlCl), dichloroethylaluminum (EtAlCl2), and sesquiethylaluminum chloride (EASC), with dichloroethylaluminum (EtAlCl2) being preferred.

[0062] The present invention also provides a method for preparing branched polyethylene, wherein ethylene gas is introduced into solvent II containing a main catalyst α-diimine nickel complex and a co-catalyst, the ethylene pressure is kept constant, and polymerization is carried out by stirring to obtain branched polyethylene.

[0063] The molar ratio of the α-diimine nickel complex to the co-catalyst is 1:(100-4000), preferably 1:(300-3500), and more preferably 1:(300-3000). The molar amount of the α-diimine nickel complex is based on the molar amount of nickel therein, and the molar amount of the co-catalyst is based on the molar amount of aluminum therein.

[0064] Solvent II is selected from one or more of aromatic hydrocarbon solvents, halogenated hydrocarbon solvents, alcohol solvents, ether solvents or alkane solvents, preferably one or more of toluene, xylene, dichloromethane, ethanol, tetrahydrofuran, hexane and cyclohexane, and more preferably toluene.

[0065] The molar volume ratio of the α-diimine nickel complex to solvent II is (0.5-5×10⁻⁶). -3 )mmol:(20-100)mL, preferably (1-3×10 -3 )mmol: (50-100)mL, such as (2×10 -3 )mmol:(100)mL.

[0066] The pressure ratio of the α-diimine nickel complex to ethylene is (0.5-5×10). -3 )mmol: 1-16atm, preferably (1-4×10 -3 )mmol: 3-13atm, more preferably (2×10 mmol / L) -3 mmol: 5-10 atm.

[0067] The reaction temperature is 15-70℃, preferably 20-60℃.

[0068] The reaction time is 5-80 min, preferably 30-60 min.

[0069] After the reaction is complete, the ethylene supply is stopped, the reactor is vented, and a hydrochloric acid ethanol solution (such as a 15 wt% hydrochloric acid ethanol solution) is added to the reaction solution for quenching. After filtration and vacuum drying, branched polyethylene is obtained.

[0070] This invention provides an α-diimine nickel complex catalyst with a catalytically active center. The molecular weight and degree of branching of the polymer can be controlled by adjusting the N-aryl ortho-group in the α-diimine nickel complex molecule and the polymerization conditions. In catalyzing ethylene polymerization, the activity can reach 1.0 × 10⁻⁶. 7 g·mol -1 (Ni)·h -1 The weight-average molecular weight (Mw) of the prepared polyethylene ranged from 1.0 to 15.19 × 10⁻⁶. 5 g·mol -1 The molecular weight fluctuates between 1.9 and 3.12, with polyethylene having 86-102 branches per 1000 carbon atoms. The tensile strength can reach 10.06 MPa, and the elongation at break can reach 366%.

[0071] Example

[0072] Example 1

[0073] In a 100 mL round-bottom flask, zinc dichloride (0.40 g, approx. 3.0 mmol), 2,3-butanedione (0.26 g, approx. 3.0 mmol), 2,6-dimethyl-4-bis(4-fluorophenyl)methylaniline (1.9 g, approx. 6.0 mmol), and acetic acid (2 mL) were added. The reaction mixture was stirred and heated at 80 °C for 4 h. After cooling to room temperature, diethyl ether (10 mL) was added, and the resulting yellow precipitate, α-diimine zinc complex, was filtered off.

[0074] The α-diimine zinc complex was then dissolved in dichloromethane, and a saturated aqueous solution of potassium carbonate was added. The mixture was stirred at room temperature for 1.5 h. The organic layer was extracted using a separating funnel, washed three times with water, and dried over magnesium sulfate. After removing volatiles by rotary evaporation, the mixture was recrystallized from n-hexane and washed with acetonitrile to give 1.15 g of ligand L1 as a yellow powder. Yield: 55%. Ligand L1:

[0075]

[0076] The NMR structure confirmation data are as follows:

[0077] FT-IR (cm) -1): 2970(w), 2914(w), 2888(w), 1892(w), 1648(m, vC=N), 1599(m), 1504(s), 1471(w), 1432(w), 1382(w), 1355(w), 1294( w), 1217(s), 1155(s), 1135(w), 1117(w), 1095(w), 1013(m), 962(w), 936(w), 893(w), 835(s), 783(m), 754(m), 716(w).

[0078] 1 H NMR (CDCl3, 400MHz, TMS): δ7.07 (t, J=5.6Hz, 8H, Ar-H), 6.98 (t, J=8.8Hz, 8H, Ar-H), 6 .77(s, 4H, Ar-H), 5.44(s, 2H, CH(p-FPh)2), 2.04(s, 6H, MeC=N), 1.98(s, 12H, Ar-Me).

[0079] 13 C NMR (CDCl3, 100MHz, TMS): δ168.26 (N=CMe), 162.67 (p-FC6H5), 160.24 (p-FC6H5), 146.75, 139.95, 139.91, 138.34, 130.81, 130.73, 128.82, 124.80, 115.21, 115.00, 54.82(CH(p-FPh)2), 17.91(CH3), 15.97(N=CMe).

[0080] 19 F NMR (470MHz, CDCl3): δ-116.85.

[0081] Elemental analysis: C46H40N2 (696.83) Theoretical values: C, 79.29; H, 5.79; N, 4.02. Experimental values: C, 78.89; H, 5.77; N, 3.69.

[0082] Example 2

[0083] Ligand L2 was prepared according to the method in Example 1, except that 2,6-dimethyl-4-bis(4-fluorophenyl)methylaniline was replaced with an equimolar amount of 2-methyl-6-ethyl-4-bis(4-fluorophenyl)methylaniline. Yield: 52%. Ligand L2:

[0084]

[0085] FT-IR (cm)-1 ): 2968(w), 2918(w), 2859(m), 1895(w), 1655(m, vC=N), 1600(m), 1504(s), 1460(w), 1425(w), 1377(w), 1357(m), 1295 (w), 1219(s), 1157(s), 1118(m), 1097(w), 1016(w), 966(w), 934(w), 873(w), 832(s), 786(m), 757(w), 717(w), 639(w).

[0086] 1 H NMR (CDCl3, 400MHz, TMS): δ7.10-7.06 (m, 8H, Ar-H), 6.99 (t, J=8.6Hz, 8H, Ar-H), 6.78 (d, J=12.7Hz, 4H, Ar-H ), 5.46(s, 2H, CH(p-FPh)2), 2.38-2.29(m, 4H, Ar-CH2CH3), 2.05(s, 6H), 1.96(s, 6H), 1.08(t, J=7.5Hz, 6H).

[0087] 13 C NMR (CDCl3, 100MHz, TMS): δ168.26 (N=CMe), 162.66 (p-FC6H5), 160.23 (p-F C6H5), 146.25, 140.01, 139.98, 138.45, 131.10, 131.07, 130.81, 130.73, 12 8.82, 127.20, 127.17, 124.48, 115.19, 114.98, 54.91(CH(p-FPh)2), 24.94( CH2), 24.89(CH2), 17.91(CH3), 16.15(CH3), 13.75(N=CMe), 13.72(N=CMe).

[0088] 19 F NMR (470MHz, CDCl3): δ-116.88.

[0089] Elemental analysis: C48H44N2 (724.89) Theoretical values: C, 79.53; H, 6.12; N, 3.86. Experimental values: C, 79.43; H, 6.02; N, 3.49.

[0090] Example 3

[0091] Ligand L3 was prepared according to the method in Example 1, except that 2,6-dimethyl-4-bis(4-fluorophenyl)methylaniline was replaced with an equimolar amount of 2,4-di(bis(4-fluorophenyl)methyl)-6-methylaniline. Yield: 36%. Ligand L3:

[0092]

[0093] FT-IR (cm) -1 ): 2972(w), 2918(w), 2877(w), 1892(w), 1647(m, vC=N), 1601(m), 1506(s), 1467(w), 1421(w), 1366(m), 1333( w), 1300(w), 1227(s), 1156(s), 1131(m), 1095(m), 1016(w), 943(w), 829(s), 785(m), 753(w), 717(w), 668(w).

[0094] 1 H NMR (CDCl3, 400 MHz, TMS): Two isomers were present in a 5:1 ratio, δ 6.95–6.91 (m, 16H, Ar-H), 6.88–6.81 (m, 18H, Ar-H), 6.37 (s, Ar-H, integrated to 0.33H, isomer 2), 6.32 (s, Ar-H, integrated to 1.65H, isomer 1), 5.38 (s, 2H, CH(p-FPh)2), 5.22 (s, CH(p-FPh)2, integrated to 1.65H, isomer 2), 5.19 (s, CH(p-FPh)2, integrated to 0.33H, isomer 2), 1.90 (s, MeC=N, integrated to 5H, isomer 1), 1.88 (s, MeC=N, integrated to 1H, isomer 2), 1.53 (s, Ar-Me, integrated to 1H, isomer 2) and 1.34 (s, Ar-Me, integrated to 5H, isomer 1).

[0095] 13C NMR (CDCl3, 100MHz, TMS): δ168.73 (N=CMe), 162.67 (p-FC6H5), 162.66 (p-FC6H5), 162.59 (p-FC6H5), 160.23 (p-FC6H5) , 160.22(p-FC6H5), 160.15(p-FC6H5), 146.03, 139.71, 139.68, 139.63, 139.60, 138.77, 138.41, 138.11, 138.08, 132.4 1, 130.78, 130.70, 130.61, 130.53, 129.54, 128.40, 124.41, 115.52, 115.31, 115.18, 115.16, 114.97, 114.95, 114.74, 5 4.67(CH(p-FPh)2), 50.91(CH(p-FPh)2), 50.39(CH(p-FPh)2), 17.85(CH3), 17.81(CH3), 16.37(N=CMe), 15.97(N=CMe).

[0096] 19 F NMR (470MHz, CDCl3): δ-115.87, -116.69, -116.80..

[0097] Elemental analysis: C70H52N2 (724.89) Theoretical values: C, 78.34; H, 4.88; N, 2.16. Experimental values: C, 78.78; H, 5.05; N, 2.08.

[0098] Example 4

[0099] Ligand L4 was prepared according to the method in Example 1, except that 2,6-dimethyl-4-bis(4-fluorophenyl)methylaniline was replaced with an equimolar amount of 2,4-di(bis(4-fluorophenyl)methyl)-6-ethylaniline. Yield: 41%. Ligand L4:

[0100]

[0101] FT-IR (cm) -1): 3038(w), 2969(w), 2877(w), 1894(w), 1643(m, vC=N), 1601(m), 1505(s), 1450(w), 1420(w), 1363(w), 1307( w), 1225(s), 1156(s), 1125(m), 1094(w), 1014(w), 940(w), 900(w), 830(s), 787(m), 750(w), 718(w), 668(w).

[0102] 1 H NMR (CDCl3, 400 MHz, TMS): Two isomers were present in a 5:1 ratio, δ 6.95–6.93 (m, 16H, Ar-H), 6.90–6.81 (m, 18H, Ar-H), 6.37 (s, Ar-H, integrated to 0.33H, isomer 2), 6.31 (s, Ar-H, integrated to 1.65H, isomer 1), 5.38 (s, 2H, CH(p-FPh)2), 5.21 (s, CH(p-FPh)2, integrated to 1.65H, isomer 1), 5.17 (s, CH(p-FPh)2, integrated to 0.33H (isomer 2), 2.18 (q, 4H, J = 7.2Hz, Ar-CH2CH3), 1.53 (s, MeC = N, integrated to 1H, isomer 2), 1.35 (s, MeC = N, integrated to 5H, isomer 1), 1.12 (t, J = 7.5Hz, Ar-CH2CH3, integrated to 5H, isomer 1), (t, J = 7.5Hz, Ar-CH2CH3, integrated to 1H, isomer 2).

[0103] 13C NMR (CDCl3, 100MHz, TMS): δ168.69 (N=CMe), 162.66 (p-FC6H5), 162.61 (p-FC6H5), 162.58 (p-FC6H5), 160.22 (p-FC6H5), 160.17 (p-FC6H5 ), 160.14(p-FC6H5), 145.55, 139.79, 139.75, 139.72, 139.69, 138.96, 138.93, 138.42, 138.10, 131.85, 130.76, 130.68, 130.61, 130.59 , 130.58, 130.53, 130.52, 130.28, 128.60, 128.40, 127.71, 127.42, 115.48, 115.37, 115.26, 115.15, 114.94, 114.92, 114.71, 54.79(CH( p-FPh)2), 50.89(CH(p-FPh)2), 50.40(CH(p-FPh)2), 24.49(CH2), 23.97(CH2), 16.57(CH3), 16.21(CH3), 13.66(N=CMe), 13.43(N=CMe).

[0104] 19 F NMR (470MHz, CDCl3): δ-115.86, -116.72, -116.84.

[0105] Elemental analysis: C72H56N2 (1101.24) Theoretical values: C, 78.53; H, 5.13; N, 2.54. Experimental values: C, 78.68; H, 5.26; N, 2.29.

[0106] Example 5

[0107] L5 was prepared according to the method in Example 1, except that 2,6-dimethyl-4-bis(4-fluorophenyl)methylaniline was replaced with an equimolar amount of 2,4-di(bis(4-fluorophenyl)methyl)-6-isopropylaniline. Yield: 43%. Ligand L5:

[0108]

[0109] FT-IR (cm) -1): 3039(w), 2969(w), 2873(w), 1895(w), 1643(m, vC=N), 1601(m), 1505(s), 1452(w), 1420(w), 1363(m), 1300(w), 1225(s), 1156(s), 1125(m), 1095(w), 1015(w), 962(w), 940(w), 903(w), 830(s), 787(m), 750(w), 718(w), 668(w).

[0110] 1 ¹H NMR (CDCl₃, 400 MHz, TMS): Two isomers were present in a 5:1 ratio, δ 6.95–6.92 (m, 16H, Ar-H), 6.91–6.80 (m, 18H, Ar-H), 6.33 (s, Ar-H, integrates to 0.33H, isomer 2), 6.28 (s, Ar-H, integrates to 1.65H, isomer 1), 5.38 (s, 2H, CH(p-FPh)₂), 5.18 (s, CH(p-FPh)₂, integrates to 1.65H, isomer 1), 5.15 (s, CH(p-FPh)₂, integrates to 0.33H (isomer 2), 2.52-2.40 (m, 2H, Ar-CH(CH3)2), 1.58 (s, MeC=N, integrated to 1H, isomer 2), 1.35 (s, MeC=N, integrated to 5H, isomer 1), 1.15 (d, J=6.9Hz, Ar-CHMe2, integrated to 5H, isomer 1), 1.02 (d, J=6.8Hz, Ar-CHMe2, integrated to 1H, isomer 2).

[0111] 13C NMR (CDCl3, 100MHz, TMS): δ 168.78 (N=CMe), 162.64 (p-FC6H5), 162.62 (p-FC6H5), 162.57 (p-FC6H5), 160.21 (p-FC6H5), 160.17 (p-FC6H5), 1 60.13(p-FC6H5), 144.81, 139.86, 139.82, 139.77, 139.74, 139.06, 13 9.03, 138.45, 138.10, 138.07, 135.34, 135.12, 131.62, 130.76, 130.6 8, 130.59, 130.52, 128.48, 128.32, 125.00, 115.43, 115.22, 115.14, 114.93, 114.90, 114.68, 54.88(CH(p-FPh)2), 50.99(CH(p-FPh)2), 50. 53(CH(p-FPh)2), 28.37(-CH(CH3)2), 27.88(-CH(CH3)2), 23.86(CH3), 23.09(CH3), 22.63(CH3), 22.30(CH3), 16.77(N=CMe), 16.48(N=CMe).

[0112] 19 F NMR (470MHz, CDCl3): δ-115.85, -116.75, -116.85

[0113] Elemental analysis: C74H60N2 (1129.30) Theoretical values: C, 79.53; H, 6.12; N, 3.86. Experimental values: C, 79.64; H, 6.22; N, 3.54.

[0114] Example 6

[0115] At room temperature, 0.05 g of nickel dimethyl ether bromide (approximately 0.15 mmol) and ligand L1 (0.11 g, approximately 0.16 mmol) prepared in Example 1 were mixed and dissolved in 5 mL of tetrahydrofuran. The mixture was stirred for 12 h under nitrogen protection. After removing the tetrahydrofuran under reduced pressure, anhydrous diethyl ether was added, and a brick-red solid precipitated. The precipitate was filtered, washed with diethyl ether, and dried to obtain the brick-red solid, which was the complex Ni1. Yield: 76%.

[0116]

[0117] The structural verification data is as follows:

[0118] FT-IR (cm) -1):3043(w), 2962(w), 2913(w), 1895(w), 1639(m, vC=N), 1602(m), 1505(s), 1473(w), 1413(w), 1375( w), 1300(w), 1223(s), 1157(s), 1097(w), 1013(w), 896(w), 829(s), 780(m), 753(m), 722(w), 688(w).

[0119] 19 F NMR (470MHz, CDCl3): δ-115.58.

[0120] Elemental analysis: C46H40N2 (915.34) Theoretical values: C, 60.36; H, 4.40; N, 3.06. Experimental values: C, 59.96; H, 4.41; N, 3.02.

[0121] Example 7

[0122] Ni2 was prepared according to the method in Example 6, except that L1 was replaced with an equimolar amount of L2 prepared in Example 2. Yield: 79%.

[0123]

[0124] The structural verification data is as follows:

[0125] FT-IR (cm) -1 ):2970(w), 2913(w), 2875(m), 1892(w), 1644(m, vC=N), 1601(m), 1505(s), 1462(w), 1413(w), 1375( w), 1295(w), 1222(s), 1157(s), 1096(w), 1013(w), 988(w), 902(w), 835(s), 782(w), 748(w), 683(w).

[0126] 19 F NMR (470MHz, CDCl3): δ-115.64.

[0127] Elemental analysis: C48H44N2 (943.39%) Theoretical value: 61.11; H, 4.70; N, 2.97. Experimental value: C, 61.52; H, 4.49; N, 2.59

[0128] Example 8

[0129] Ni3 was prepared according to the method in Example 6, except that L1 was replaced with an equimolar amount of L3 obtained in Example 3. Yield: 76%.

[0130]

[0131] The structural verification data is as follows:

[0132] FT-IR (cm) -1 ): 3069(w), 2911(w), 2861(w), 1902(w), 1642(m, vC=N), 1601(m), 1505(s), 1468(w), 1439(w), 1413(m ), 1378(w), 1300(w), 1225(s), 1157(s), 1097(m), 1016(w), 881(w), 839(s), 791(m), 761(w), 725(w).

[0133] 19 F NMR (470MHz, CDCl3): δ-114.48, -115.34, -115.36, -116.40.

[0134] Elemental analysis: C70H52N2 (1291.69) Theoretical values: C, 65.09; H, 4.06; N, 2.17. Experimental values: C, 65.03; H, 3.87; N, 1.84.

[0135] Example 9

[0136] Ni4 was prepared according to the method in Example 6, except that an equimolar amount of L4 obtained in Example 4 was used to replace L1. Yield: 78%.

[0137]

[0138] The structural verification data is as follows:

[0139] FT-IR (cm) -1 ): 3069(w), 2911(w), 2861(w), 1902(w), 1642(m, vC=N), 1601(m), 1505(s), 1468(w), 1439(w), 1413(m ), 1378(w), 1300(w), 1225(s), 1157(s), 1097(m), 1016(w), 881(w), 839(s), 791(m), 761(w), 725(w).

[0140] 19F NMR (470MHz, CDCl3): δ-114.48, -115.34, -115.36, -116.40.

[0141] Elemental analysis: C72H56N2 (1319.74) Theoretical values: C, 65.53; H, 4.28; N, 2.12. Experimental values: C, 65.70; H, 4.10; N, 2.05.

[0142] Example 10

[0143] Ni5 was prepared according to the method in Example 6, except that L1 was replaced with an equimolar amount of L5 prepared in Example 5. Yield: 78%.

[0144]

[0145] The structural verification data is as follows:

[0146] FT-IR (cm) -1 ):2963(w), 2913(w), 2873(w), 1977(w), 1640(m, 6555C=N), 1602(m), 1505(s), 1451(w), 1411(w), 1379(w) , 1302(w), 1225(s), 1157(s), 1096(w), 1015(w), 992(w), 873(s), 830(s), 793(m), 750(w), 724(w), 676(w).

[0147] 19 F NMR (470MHz, CDCl3): δ-114.48, -115.34, -115.36, -116.40.

[0148] Elemental analysis: C74H60N2 (1347.80) Theoretical values: C, 65.95; H, 4.49; N, 2.08. Experimental values: C, 65.51; H, 4.57; N, 1.83.

[0149] Example 11

[0150] Ethylene polymerization under pressure was catalyzed by the complex Ni2 and methylaluminoxane (MAO).

[0151] The ethylene polymerization process was carried out in a 250 mL stainless steel autoclave equipped with a pressure control system, temperature controller, and mechanical stirrer. The autoclave was evacuated and backfilled with nitrogen three times, followed by ethylene backfilling once. When the reactor reached 30 °C, toluene (25 mL) and a Ni₂ solution dissolved in toluene (25 mL, with Ni molar amount of 2 μmol) were added sequentially. Then, the required amount of co-catalyst (2.74 mL of a 1.46 mol / L MAO toluene solution, approximately 4 mmol of MAO molar amount) and toluene (50 mL) were added, resulting in an Al:Ni molar ratio of approximately 2000. Ethylene was then continuously introduced, and the mixture was stirred while maintaining an ethylene pressure of P(C₂H₄) = 10 atm for 30 min at 30 °C. After the reaction was complete, the ethylene supply was stopped, and the reactor was vented. The resulting mixture was quenched with a 15% hydrochloric acid-ethanol solution and filtered. After vacuum drying at 50 °C for 8 hours, the polymer was weighed.

[0152] Polymerization activity: 6.84 × 10 6 g·mol -1 (Ni)·h -1 Tm = 105.5℃. (Tm is the melting temperature of the polymer, obtained by DSC testing), and the polymer's weight-average molecular weight is Mw = 2.25 × 10⁻⁶. 5 g·mol -1 The molecular weight distribution index (PDI) is 2.27 (Mw is the weight-average molecular weight of the polymer, obtained by heated GPC testing).

[0153] Example 12

[0154] Polyethylene was prepared according to the method in Example 11, except that an equimolar amount of 2.45 mol / L MMAO n-heptane solution (1.6 mL) was used instead of MAO as a cocatalyst. The Al:Ni molar ratio was approximately 2000 at this time.

[0155] The polymerization activity is 4.11 × 10⁻⁶. 6 g·mol -1 (Ni)·h -1 , Tm=112.04℃, Mw=2.53×10 5 g·mol -1 PDI = 2.62.

[0156] Example 13

[0157] Polyethylene was prepared according to the method in Example 11, except that 1.6 mL of 0.5 mol / L EtAlCl2 hexane solution was added instead of MAO as a cocatalyst, and the Al:Ni molar ratio was approximately 400.

[0158] The polymerization activity is 5.21 × 10⁻⁶. 6 g·mol -1 (Ni)·h -1 , Tm=104.4℃, Mw=2.53×10 5 g·mol -1 PDI = 2.55.

[0159] Example 14

[0160] Polyethylene was prepared according to the method in Example 11, except that 1.6 mL of 0.5 mol / L Et2AlCl toluene solution was added instead of MAO as a cocatalyst, and the Al:Ni molar ratio was approximately 400.

[0161] The polymerization activity is 4.81 × 10⁻⁶. 6 g·mol -1 (Ni)·h -1 , Tm=106.3℃, Mw=1.91×10 5 g·mol -1 PDI = 2.72.

[0162] Example 15

[0163] Polyethylene was prepared according to the method in Example 11, except that 1.6 mL of 0.5 mol / L EASC toluene solution was added instead of MAO as a cocatalyst, and the Al:Ni molar ratio was approximately 400.

[0164] The polymerization activity is 4.08 × 10⁻⁶. 6 g·mol -1 (Ni)·h -1 , Tm=106.8℃, Mw=2.34×10 5 g·mol -1 PDI = 3.12.

[0165] Example 16

[0166] Polyethylene was prepared according to the method in Example 11, except that 1.4 mL of a toluene solution of MAO with a concentration of 1.46 mol / L was added as a co-catalyst, at which point the Al:Ni molar ratio was approximately 1000.

[0167] The polymerization activity is 1.12 × 10⁻⁶. 6 g·mol -1 (Ni)·h -1 , Tm=127.6℃, Mw=5.39×10 5 g·mol -1 PDI = 2.59.

[0168] Example 17

[0169] Polyethylene was prepared according to the method in Example 11, except that 2.05 mL of a toluene solution of MAO with a concentration of 1.46 mol / L was added as a co-catalyst, at which point the Al:Ni molar ratio was approximately 1500.

[0170] Polymerization activity: 7.17 × 10 6 g·mol -1 (Ni)·h -1 , Tm=107.5℃, Mw=3.13×10 5 g·mol -1 PDI = 2.58.

[0171] Take 50 mg of the obtained polymer, dissolve it in 5 mL of deuterated chlorobenzene, and test the polymer at 100 °C. 13 C data. Signal accumulation of 2048 times yielded peak shifts between 20-40 ppm, indicating shifts in methyl, methylene, and methine groups, confirming the obtained polymer is branched polyethylene (see NMR spectrum for details). Figure 1 ).

[0172] Example 18

[0173] Polyethylene was prepared according to the method in Example 11, except that 3.42 mL of a 1.46 mol / L MAO toluene solution was added as a co-catalyst, at which point the Al:Ni molar ratio was approximately 2500.

[0174] Polymerization activity: 6.12 × 10⁻⁶ 7 g·mol -1 (Ni)·h -1 , Tm=116.0℃, Mw=2.14×10 5 g·mol -1 PDI = 2.44.

[0175] Example 19

[0176] Polyethylene was prepared according to the method in Example 11, except that 4.11 mL of a 1.46 mol / L MAO toluene solution was added as a co-catalyst, at which point the Al:Ni molar ratio was approximately 3000.

[0177] Polymerization activity: 5.76 × 10 6 g·mol -1 (Ni)·h -1 , Tm=111.3℃, Mw=1.86×10 5 g·mol -1 PDI = 2.68.

[0178] Example 20

[0179] Polyethylene was prepared according to the method in Example 17, except that the polymerization temperature was 20°C.

[0180] Polymerization activity: 1.05 × 10⁻⁵ 6 g·mol -1 (Ni)·h -1 The polymer has a Tm of 129.6℃ and a Mw of 6.14 × 10⁻⁶. 5 g·mol -1 PDI = 2.34.

[0181] Example 21

[0182] Polyethylene was prepared according to the method in Example 17, except that the polymerization temperature was 40°C.

[0183] Polymerization activity: 3.56 × 10 6 g·mol -1 (Ni)·h -1 , Tm=121.5℃, Mw=2.25×10 5 g·mol -1 PDI = 2.77.

[0184] Example 22

[0185] Polyethylene was prepared according to the method in Example 17, except that the polymerization temperature was 50°C.

[0186] Polymerization activity: 2.48 × 10⁻⁶ 6 g·mol -1 (Ni)·h -1 , Tm=118.7℃, Mw=1.80×10 5 g·mol -1 PDI = 2.20.

[0187] Example 23

[0188] Polyethylene was prepared according to the method in Example 17, except that the polymerization temperature was 60°C.

[0189] Polymerization activity: 1.02 × 10⁻⁶ 6 g·mol -1 (Ni)·h -1 , Tm=93.4℃, Mw=1.00×10 5 g·mol -1 PDI = 3.06.

[0190] Example 24

[0191] Polyethylene was prepared according to the method in Example 17, except that the polymerization time was 5 min.

[0192] Polymerization activity: 15.60 × 10 6 g·mol -1 (Ni)·h -1 , Tm=116.5℃, Mw=2.31×10 5 g·mol -1 PDI = 2.73.

[0193] Example 25

[0194] Polyethylene was prepared according to the method in Example 17, except that the polymerization time was 15 min.

[0195] Polymerization activity: 11.84 × 10 6 g·mol -1 (Ni)·h -1 , Tm=113.3℃, ​​Mw=3.12×10 5 g·mol -1 PDI = 2.14.

[0196] Example 26

[0197] Polyethylene was prepared according to the method in Example 17, except that the polymerization time was 45 min.

[0198] Polymerization activity: 5.11 × 10 6 g·mol -1 (Ni)·h -1 , Tm=124.9℃, Mw=3.18×10 5 g·mol -1 PDI = 2.00.

[0199] Example 27

[0200] Polyethylene was prepared according to the method in Example 17, except that the polymerization time was 60 min.

[0201] Polymerization activity: 3.94 × 10 6 g·mol -1 (Ni)·h -1 , Tm=126.4℃, Mw=4.05×10 5 g·mol -1 PDI = 2.92.

[0202] Example 28

[0203] Polyethylene was prepared according to the method in Example 17, except that the ethylene pressure was 5 atm.

[0204] Polymerization activity: 2.77 × 10 6 g·mol -1 (Ni)·h -1 , Tm=121.1℃, Mw=2.42×105g·mol -1 PDI = 2.43.

[0205] Example 29

[0206] Polyethylene was prepared according to the method in Example 17, except that the ethylene pressure was 1 atm.

[0207] Polymerization activity: 0.8 × 10 5 g·mol -1 (Ni)·h -1 , Tm=65.4℃, Mw=0.71×10 5 g·mol -1 PDI = 5.51.

[0208] Example 30

[0209] Polyethylene was prepared according to the method in Example 17, except that Ni2 was replaced with an equimolar amount of Ni1.

[0210] Polymerization activity: 6.01 × 10⁻⁶ 6 g·mol -1 , Tm=111.3℃, Mw=9.11×10 5 g·mol -1 PDI = 2.88.

[0211] Example 31

[0212] Polyethylene was prepared according to the method in Example 17, except that Ni2 was replaced with an equimolar amount of Ni3.

[0213] Polymerization activity: 3.93 × 10 6 g·mol -1 The polymer has a Tm of 116.6℃ and a Mw of 9.42 × 10⁻⁶. 5 g·mol -1 PDI = 2.18.

[0214] Example 32

[0215] Polyethylene was prepared according to the method in Example 17, except that Ni2 was replaced with an equimolar amount of Ni4.

[0216] Polymerization activity: 1.54 × 10 6 g·mol -1, Tm=116.9℃, Mw=3.63×10 5 g·mol -1 PDI = 2.75.

[0217] Example 33

[0218] Polyethylene was prepared according to the method in Example 17, except that Ni2 was replaced with an equimolar amount of Ni5.

[0219] Polymerization activity: 1.13 × 10 6 g·mol -1 The polymer has a Tm of 95.5℃ and a Mw of 10.48 × 10⁻⁶. 5 g·mol -1 PDI = 2.37.

[0220] Example 34

[0221] Polyethylene was prepared according to the method in Example 33, except that the polymerization temperature was 40°C.

[0222] Polymerization activity: 3.17 × 10 6 g·mol -1 , Tm=68.1℃, Mw=8.67×10 5 g·mol -1 PDI = 2.49.

[0223] The obtained polyethylene was subjected to mechanical tensile property testing. Three tests were conducted and the average value was taken. The tensile strength was 10.06 MPa and the elongation at break was 366%. The obtained polymer was subjected to stress-strain recovery test, and the elastic recovery rate was 46.1%.

[0224] Example 35

[0225] Polyethylene was prepared according to the method in Example 33, except that the polymerization temperature was 50°C.

[0226] Polymerization activity: 1.01 × 10⁻⁶ 6 g·mol -1 , Tm=63.1℃, Mw=7.44×10 5 g·mol -1 PDI = 2.65.

[0227] The obtained polymer was subjected to mechanical tensile property tests. Three tests were conducted and the average value was taken. The tensile strength was 5.41 MPa and the elongation at break was 405%. The obtained polymer was subjected to stress-strain recovery tests, and the elastic recovery rate was 48.0%.

[0228] Example 36

[0229] Polyethylene was prepared according to the method in Example 11, except that 1.2 mL of 0.5 mol / L EtAlCl2 hexane solution (0.6 mmol of EtAlCl2) was added instead of MAO as a cocatalyst, and the Al / Ni molar ratio was 300:1.

[0230] Polymerization activity: 3.28 × 10⁻⁶ 6 g·mol -1 (Ni)·h -1 The polymer has a Tm of 107.7℃ and a Mw of 2.34 × 10⁻⁶. 5 g·mol -1 PDI = 2.87.

[0231] Example 37

[0232] Polyethylene was prepared according to the method in Example 36, except that 1.6 mL of a 0.5 mol / L EtAlCl2 hexane solution (0.8 mmol of EtAlCl2) was added as a co-catalyst, at which point the Al / Ni molar ratio was 400:1.

[0233] Polymerization activity: 5.21 × 10⁻⁶ 6 g·mol -1 (Ni)·h -1 , Tm=104.4℃, Mw=2.53×10 5 g·mol -1 PDI = 2.55.

[0234] Example 38

[0235] Polyethylene was prepared according to the method in Example 36, except that 2 mL of a 0.5 mol / L EtAlCl2 hexane solution (1 mmol of EtAlCl2) was added as a co-catalyst, and the Al / Ni molar ratio was 500:1.

[0236] Polymerization activity: 5.83 × 10 6 g·mol -1 (Ni)·h -1 , Tm=106.3℃, Mw=2.48×10 5 g·mol -1 PDI = 2.59.

[0237] Example 39

[0238] Polyethylene was prepared according to the method in Example 36, except that 2.4 mL of a 0.5 mol / L EtAlCl2 hexane solution (1.2 mmol of EtAlCl2) was added as a co-catalyst, at which point the Al / Ni molar ratio was 600:1.

[0239] Polymerization activity: 6.48 × 10 6 g·mol -1 (Ni)·h -1 Tm = 99℃, Mw = 2.05 × 10 5 g·mol -1 PDI = 2.79.

[0240] Example 40

[0241] Polyethylene was prepared according to the method in Example 36, except that 2.8 mL of a 0.5 mol / L EtAlCl2 hexane solution (1.4 mmol of EtAlCl2) was added as a co-catalyst, at which point the Al / Ni molar ratio was 700:1.

[0242] Polymerization activity: 4.84 × 10 6 g·mol -1 (Ni)·h -1 The polymer's Tm is 110.1℃ and Mw is 2.63 × 10⁻⁶. 5 g·mol -1 PDI = 2.05.

[0243] Example 41

[0244] Polyethylene was prepared according to the method in Example 36, except that 3.2 mL of a 0.5 mol / L EtAlCl2 hexane solution (1.6 mmol of EtAlCl2) was added as a co-catalyst, at which point the Al / Ni molar ratio was 800:1.

[0245] Polymerization activity: 4.24 × 10 6 g·mol -1 (Ni)·h -1 The polymer has a Tm of 112.7℃ and a Mw of 2.48 × 10⁻⁶. 5 g·mol -1 PDI = 2.31.

[0246] Example 42

[0247] Polyethylene was prepared according to the method in Example 36, except that 2.4 mL of a 0.5 mol / L EtAlCl2 hexane solution (1.2 mmol of EtAlCl2) was added as a co-catalyst, at which point the Al / Ni molar ratio was 600:1 and the polymerization temperature was 20 °C.

[0248] Polymerization activity: 5.30 × 10 6 g·mol -1 (Ni)·h -1 , Tm=116.5℃, Mw=3.64×10 5 g·mol -1 PDI = 2.73.

[0249] Example 43

[0250] Polyethylene was prepared according to the method in Example 36, except that 2.4 mL of a 0.5 mol / L EtAlCl2 hexane solution (1.2 mmol of EtAlCl2) was added as a co-catalyst, at which point the Al / Ni molar ratio was 600:1 and the polymerization temperature was 40°C.

[0251] Polymerization activity: 5.82 × 10 6 g·mol -1 (Ni)·h -1 , Tm=87.9℃, Mw=1.18×10 5 g·mol -1 PDI = 2.12.

[0252] Example 44

[0253] Polyethylene was prepared according to the method in Example 36, except that 2.4 mL of a 0.5 mol / L EtAlCl2 hexane solution (1.2 mmol of EtAlCl2) was added as a co-catalyst, at which point the Al / Ni molar ratio was 600:1 and the polymerization temperature was 50 °C.

[0254] Polymerization activity: 4.88 × 10 6 g·mol -1 (Ni)·h -1 , Tm=86.5℃, Mw=1.03×10 5 g·mol -1 PDI = 1.96.

[0255] Example 45

[0256] Polyethylene was prepared according to the method in Example 36, except that 2.4 mL of a 0.5 mol / L EtAlCl2 hexane solution (1.2 mmol of EtAlCl2) was added as a co-catalyst, at which point the Al / Ni molar ratio was 600:1 and the polymerization temperature was 60°C.

[0257] Polymerization activity: 2.39 × 10 6 g·mol -1 (Ni)·h -1 Tm = 65℃, Mw = 0.69 × 10 5 g·mol -1 PDI = 2.36.

[0258] Example 46

[0259] Polyethylene was prepared according to the method in Example 36, except that 2.4 mL of 0.5 mol / L EtAlCl2 hexane solution (1.2 mmol of EtAlCl2) was added as a co-catalyst, at which point the Al / Ni molar ratio was 600:1 and the polymerization time was 5 min.

[0260] Polymerization activity: 17.52 × 10 6 g·mol -1 (Ni)·h -1 , Tm=107.8℃, Mw=1.49×10 5 g·mol -1 PDI = 2.76.

[0261] Example 47

[0262] Polyethylene was prepared according to the method in Example 36, except that 2.4 mL of a 0.5 mol / L EtAlCl2 hexane solution (1.2 mmol of EtAlCl2) was added as a co-catalyst, at which point the Al / Ni molar ratio was 600:1 and the polymerization time was 15 min.

[0263] Polymerization activity: 7.40 × 10 6 g·mol -1 (Ni)·h -1 The polymer's Tm is 108.3℃ and Mw is 1.87 × 10⁻⁶. 5 g·mol -1 PDI = 2.46.

[0264] Example 48

[0265] Polyethylene was prepared according to the method in Example 36, except that 2.4 mL of a 0.5 mol / L EtAlCl2 hexane solution (1.2 mmol of EtAlCl2) was added as a co-catalyst, at which point the Al / Ni molar ratio was 600:1 and the polymerization time was 45 min.

[0266] Polymerization activity: 4.74 × 10 6 g·mol -1 (Ni)·h -1 , Tm=108.7℃, Mw=2.27×10 5 g·mol -1 PDI = 2.27.

[0267] Example 49

[0268] Polyethylene was prepared according to the method in Example 36, except that 2.4 mL of a 0.5 mol / L EtAlCl2 hexane solution (1.2 mmol of EtAlCl2) was added as a co-catalyst, at which point the Al / Ni molar ratio was 600:1 and the polymerization time was 60 min.

[0269] Polymerization activity: 3.73 × 10 6 g·mol -1 (Ni)·h -1 , Tm=109.5℃, Mw=2.40×10 5 g·mol -1 PDI = 2.56.

[0270] Example 50

[0271] Polyethylene was prepared according to the method in Example 36, except that 2.4 mL of a 0.5 mol / L EtAlCl2 hexane solution (1.2 mmol of EtAlCl2) was added as a co-catalyst, at which point the Al / Ni molar ratio was 600:1 and the ethylene pressure was 5 atm.

[0272] Polymerization activity: 4.93 × 10 6 g·mol -1 (Ni)·h -1 , Tm=106.7℃, Mw=1.60×10 5 g·mol -1 PDI = 2.43.

[0273] Example 51

[0274] Polyethylene was prepared according to the method in Example 36, except that 2.4 mL of a 0.5 mol / L EtAlCl2 hexane solution (1.2 mmol of EtAlCl2) was added as a co-catalyst, at which point the Al / Ni molar ratio was 600:1 and the ethylene pressure was 1 atm.

[0275] Polymerization activity: 3.5 × 10 5 g·mol -1 (Ni)·h -1 , Tm=47.8℃, Mw=0.68×10 5 g·mol -1 PDI = 1.91.

[0276] Example 52

[0277] Polyethylene was prepared according to the method in Example 11, except that: Ni1 was used instead of Ni2 as the main catalyst in an equimolar amount, and 2.4 mL of 0.5 mol / L EtAlCl2 hexane solution (1.2 mmol of EtAlCl2) was added instead of MAO as the co-catalyst, at which time the Al / Ni molar ratio was 600:1.

[0278] Polymerization activity: 6.14 × 10 6 g·mol -1 (Ni)·h -1 , Tm=109.9℃, Mw=13.8×10 5 g·mol -1 PDI = 2.17.

[0279] Example 53

[0280] Polyethylene was prepared according to the method in Example 52, except that an equimolar amount of Ni3 was used instead of Ni1 as the main catalyst.

[0281] Polymerization activity: 7.43 × 10 6 g·mol -1 (Ni)·h -1 , Tm=109.0℃, Mw=8.19×10 5 g·mol -1 PDI = 2.84.

[0282] Example 54

[0283] Polyethylene was prepared according to the method in Example 52, except that an equimolar amount of Ni4 was used instead of Ni1 as the main catalyst.

[0284] Polymerization activity: 4.95 × 10 6 g·mol-1 (Ni)·h -1 , Tm=114.0℃, Mw=1.28×10 5 g·mol -1 PDI = 2.90.

[0285] Example 55

[0286] Polyethylene was prepared according to the method in Example 52, except that an equimolar amount of Ni5 was used instead of Ni1 as the main catalyst.

[0287] Polymerization activity 4.81×10 6 g·mol -1 (Ni)·h -1 , Tm=93.3℃, ​​Mw=15.19×10 5 g·mol -1 PDI = 2.37.

[0288] Example 56

[0289] Polyethylene was prepared according to the method in Example 55, except that the polymerization temperature was 40°C.

[0290] Polymerization activity: 9.20 × 10 6 g·mol -1 , Tm=69.6℃, Mw=9.22×10 5 g·mol -1 PDI = 2.45.

[0291] Take 50 mg of the obtained polymer, dissolve it in 5 mL of deuterated chlorobenzene, and test the polymer at 100 °C. 13 C data. Signal accumulation of 2048 times yielded peak shifts between 20-40 ppm, indicating shifts in methyl, methylene, and methine groups, confirming the obtained polymer is branched polyethylene (see detailed NMR spectrum). Figure 2 ).

[0292] The obtained polymer was subjected to mechanical tensile property tests. Three tests were conducted and the average value was taken. The tensile strength was 6.5 MPa and the elongation at break was 223%. The obtained polymer was subjected to stress-strain recovery tests, and the elastic recovery rate was 47.7%.

[0293] Example 57

[0294] Polyethylene was prepared according to the method in Example 55, except that the polymerization temperature was 50°C.

[0295] Polymerization activity: 4.43 × 10 6 g·mol -1, Tm=50.1℃, Mw=8.88×10 5 g·mol -1 PDI = 2.25.

[0296] The obtained polyethylene was subjected to mechanical tensile property testing. Three tests were conducted and the average value was taken. The tensile strength was 4.0 MPa and the elongation at break was 413%. The obtained polyethylene was subjected to stress-strain recovery test, and the elastic recovery rate was 52.8%.

[0297] Example 58

[0298] Polyethylene was prepared according to the method in Example 11, except that: Ni5 was used instead of Ni2 as the main catalyst, the polymerization temperature was changed to 40°C, and 2.40 mL of Et2AlCl (0.5 mol / L hexane solution) was used instead of MAO as the co-catalyst, and the molar ratio of Al to Ni was 600:1.

[0299] Polymerization activity: 8.97 × 10 6 g·mol -1 (Ni)·h -1 , Tm=77.3℃, Mw=8.36×10 5 g·mol -1 PDI = 2.68.

[0300] Take 50 mg of the obtained polymer, dissolve it in 5 mL of deuterated o-dichlorobenzene, and test the polymer at 100 °C. 13 C data. Signal accumulation of 2048 times yielded peak shifts between 20-40 ppm, indicating shifts in methyl, methylene, and methine groups, confirming the obtained polymer is branched polyethylene (see detailed NMR spectrum). Figure 3 ).

[0301] The obtained polymer was subjected to mechanical tensile property tests. Three tests were conducted and the average value was taken. The tensile strength was 5.62 MPa and the elongation at break was 211%. The obtained polymer was subjected to stress-strain recovery tests, and the elastic recovery rate was 47.8%.

[0302] Example 59

[0303] Polyethylene was prepared according to the method in Example 11, except that: Ni5 was used instead of Ni2 as the main catalyst in equal molar amounts, the polymerization temperature was changed to 40°C, and 2.40 mL of EASC (0.5 mol / L hexane solution) was used instead of MAO as the co-catalyst, and the molar ratio of Al to Ni was 600:1.

[0304] Polymerization activity: 10.03 × 10 6 g·mol-1 (Ni)·h -1 Tm = 73.8℃, polymer molecular weight Mw = 8.29 × 10⁻⁶ 5 g·mol -1 PDI = 3.12.

[0305] Take 50 mg of the obtained polymer, dissolve it in 5 mL of deuterated o-dichlorobenzene, and test the polymer at 100 °C. 13 C data. Signal accumulation of 2048 times yielded peak shifts between 20-40 ppm, indicating shifts in methyl, methylene, and methine groups, confirming the obtained polymer is branched polyethylene (see detailed NMR spectrum). Figure 4 )

[0306] The obtained polymer was subjected to mechanical tensile property tests. Three tests were conducted and the average value was taken. The tensile strength was 4.60 MPa and the elongation at break was 382%. The obtained polymer was subjected to stress-strain recovery tests, and the elastic recovery rate was 45.3%.

[0307]

[0308]

[0309] The α-diimine nickel complex catalyst provided by this invention has the following characteristics in catalyzing ethylene polymerization:

[0310] (1) The main catalysts of this invention, Ni1-Ni5, catalyze the polymerization of ethylene. The polymerization activity is affected to varying degrees by the co-catalysts. The polymerization activity of Ni2 in the presence of different co-catalysts is shown in Examples 11-15.

[0311] (2) When Ni2 is the main catalyst for ethylene polymerization, the activation of MAO and EtAlCl2 as co-catalysts respectively shows that the molecular weight gradually decreases with increasing temperature and gradually increases with increasing polymerization time.

[0312] (3) When the ortho-substituent of the catalyst (i.e., the R1 and R2 substituents in the structure of the α-diimine nickel complex) is a large substituent difluorodiphenylmethyl, it can have a positive effect on improving the thermal stability of the catalyst and the molecular weight of the polyethylene produced by the catalyst, thereby increasing the molecular weight. See Examples 56-59 for details.

[0313] (4) o-ethyl (Ni2,Ni4) catalysts have a positive impact on the production of low molecular weight polyethylene.

[0314] (5) The Ni1 to Ni5 in this invention are modified with ortho-substituents, which makes the high molecular weight polyethylene highly selective for short-chain methyl branches. Figure 1-4The type of co-catalyst (aluminum activator) also has a certain influence on the branching degree of polyethylene (EASC > Et2AlCl~EtAlCl2). Catalysts Ni1~Ni5 are more likely to combine with EASC to form highly branched polyethylene. This good control over the branching structure is reflected in the elastomer properties of polyethylene. Figure 5 ).

[0315] The present invention has been described in detail above with reference to specific embodiments and / or exemplary examples, as well as the accompanying drawings. However, these descriptions should not be construed as limiting the present invention. Those skilled in the art will understand that various equivalent substitutions, modifications, or improvements can be made to the technical solutions and embodiments of the present invention without departing from the spirit and scope of the invention, and all such modifications and improvements fall within the scope of the present invention. The scope of protection of the present invention is defined by the appended claims.

Claims

1. An α-diimine nickel complex for catalytic preparation of polyethylene, characterized in that, It has the following structure: ， Wherein, R1 is selected from alkyl groups containing C1-C6 carbon atoms, R2 is selected from alkyl groups containing C1-C6 carbon atoms or di(p-fluorophenyl)methyl groups, and X is selected from F, Cl, and Br.

2. The complex according to claim 1, characterized in that, The α-diimine nickel complex is selected from the following complexes: , , , or , X is selected from F, Cl, or Br.

3. A method for preparing the α-diimine nickel complex for catalytic preparation of polyethylene according to claim 1, characterized in that, An α-diimine nickel complex was prepared by reacting and coordinating α-diimine ligands and nickel halides in a solvent. The nickel halides were selected from NiF2, NiCl2, or NiBr2.

4. The method according to claim 3, characterized in that, The solvent is selected from one or more of ether solvents, halocarbon solvents or alcohol solvents, and the molar volume ratio of nickel halide to solvent is 0.15 mmol:(2-6) mL.

5. The method as described in claim 4, characterized in that, The solvent is selected from one or more of tetrahydrofuran, dichloromethane or ethanol, and the molar volume ratio of the nickel halide to the solvent is 0.15 mmol:(4-6) mL.

6. The method as described in claim 4, characterized in that, The solvent is tetrahydrofuran, and the molar volume ratio of the nickel halide to the solvent is 0.15 mmol: 5 mL.

7. The method according to claim 3, characterized in that, The α-diimine ligand is obtained by reacting 2,3-butanedione, substituted aniline and water-soluble zinc salt under acid catalysis to obtain an α-diimine zinc complex, which is then reacted under alkaline conditions to obtain the α-diimine ligand.

8. The method according to claim 3, characterized in that, The α-diimine ligand is prepared by the following steps: Step 1: Add 2,3-butanedione, substituted aniline and water-soluble zinc salt to an organic acid, stir and react to obtain α-diimine zinc complex; Step 2: Add the α-diimine zinc complex to solvent I, then add an aqueous carbonate solution, stir the reaction to obtain the reaction solution; Step 3: Post-process the reaction solution to obtain α-diimine ligands.

9. The method according to claim 8, characterized in that, In step 1, the substituted aniline is selected from amine compounds having the following structures: ， Wherein, R1 is selected from alkyl groups containing C1-C6 carbon atoms, and R2 is selected from alkyl groups containing C1-C6 carbon atoms or di(p-fluorophenyl)methyl; the molar ratio of 2,3-butanedione and substituted aniline is 1:(2-3.4).

10. The method as described in claim 9, characterized in that, The molar ratio of 2,3-butanedione to substituted aniline is 1:(2-2.8).

11. The method as described in claim 9, characterized in that, The molar ratio of 2,3-butanedione to substituted aniline is 1:(2-2.2).

12. The method according to claim 8, characterized in that, In step 2, solvent I is selected from one or more of haloalkane solvents.

13. The method according to claim 12, characterized in that, In step 2, solvent I is selected from one or more of chloromethane, dichloromethane, dichloroethane, or trichloromethane.

14. The method according to claim 12, characterized in that, In step 2, solvent I is dichloromethane.

15. The use of the α-diimine nickel complex of claim 1 for the catalytic preparation of polyethylene, characterized in that, It acts as the main catalyst for olefin polymerization.

16. The use as described in claim 15, characterized in that, The α-diimine nickel complex of claim 1, used as the main catalyst for the catalytic polymerization of ethylene to prepare branched polyethylene, is used as the main catalyst in the polymerization reaction; the polymerization reaction further includes a co-catalyst selected from one or more of aluminoxane, alkylaluminum and alkylaluminum chloride.

17. A method for preparing branched polyethylene, characterized in that, In the method, ethylene gas is introduced into solvent II containing the α-diimine nickel complex, the main catalyst for the catalytic preparation of polyethylene as described in claim 1, and a co-catalyst, while maintaining a constant ethylene pressure and stirring to polymerize, thereby preparing branched polyethylene. The pressure ratio of the α-diimine nickel complex to ethylene is (0.5-5×10). -3 )mmol:(1-16)atm.

18. The method as described in claim 17, characterized in that, The pressure ratio of the α-diimine nickel complex to ethylene is (1-4×10). -3 )mmol:(3-13)atm.

19. The method as described in claim 17, characterized in that, The pressure ratio of the α-diimine nickel complex to ethylene is (2×10). -3 )mmol:(5-10)atm.

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