Preparation method of alpha-diimine ligand, nickel catalyst of alpha-diimine ligand and application of nickel catalyst in olefin polymerization

Abstract

The invention discloses a preparation method of an alpha-diimine ligand, a nickel catalyst of the alpha-diimine ligand and application of the nickel catalyst in olefin polymerization, belongs to the field of catalytic synthesis, and provides a general method for ligand skeleton modification without purification means such as column chromatography / recrystallization and the like. A series of alpha-diimine ligands modified by different skeletons are simply and efficiently synthesized by a one-pot method, a corresponding Ni (II) catalyst is prepared, the synthesized Ni catalyst is utilized, and a polymerization reaction and a polymerization product are greatly regulated and controlled by means of regulating a ligand structure, polymerization temperature, ethylene pressure and the like: the molecular weight of a polymer is 14.9-647.7 kDa; the branching degree (the branching range of the polymer is less than 1-126.9 / 1000C); thermal stability (the polymerization limiting temperature is increased to 150 DEG C; the catalytic activity is as high as 2 * 10 < 8 > gmol <-1 > h <-1 > on the basis of activity.

Description

Technical Field

[0001] The invention belongs to the field of catalytic synthesis, and specifically relates to a preparation method of an alpha-diimine ligand and a nickel catalyst thereof and application of the alpha-diimine ligand in olefin polymerization. Background Art

[0002] The classic Brookhart-type α-diimine Ni(II) / Pd(II) catalyst (J.Am.Chem.Soc.1995,117,6414) is one of the most popular catalyst types in the field of olefin polymerization. After more than 20 years of exploration and research, researchers have modified the ligand structure based on steric and electronic effects, developed a variety of new α-diimine ligands and corresponding Ni(II) / Pd(II) catalysts, and achieved the preparation of branched polyolefin materials with adjustable branching density and structure using ethylene as the only monomer. In general, the most traditional modification methods of α-diimine ligands include: modification of N-aryl substituents, modification of ligand skeleton structure, and the use of binuclear or even multinuclear ligands.

[0003] From the perspective of α-diimine catalyst ligand structure design, modification of aromatic amines is more common, while examples of ligand skeleton modification are relatively rare. Existing skeleton modification methods are difficult to strike a balance between catalytic effect and synthesis difficulty. There are mainly the following problems: a. Simple synthesis has poor catalytic effect: that is, purchasing commercial diketone compounds with simple structures and directly condensing them with aromatic amines to synthesize ligands. The synthesis is simple, but the catalyst polymerization effect is mostly poor; b. The synthesis of catalysts with good catalytic effect is complex: catalysts with good catalytic effect often have complex ligand structures, and most of them are synthesized by first synthesizing new diketone structures and then condensing them with amines to obtain ligands. Such new diketones often have complex synthesis routes and high requirements for experiments and post-processing; c. The skeleton structure is limited by the chemical structure of the raw diketone, that is, the skeleton structure of the final ligand is determined by the raw diketone structure. Once synthesized, it cannot be changed, the structure is single, and the scalability is poor. The above problems have limited the application scope of ligand skeleton modification methods to a certain extent.

[0004] Therefore, it is urgent to develop a simple, efficient and universal synthetic method to achieve efficient design and synthesis of ligand structures, and to create a series of catalysts with outstanding polymerization effects. Summary of the invention

[0005] The purpose of this section is to summarize some aspects of embodiments of the present invention and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section and the specification abstract and the invention title of this application to avoid blurring the purpose of this section, the specification abstract and the invention title, and such simplifications or omissions cannot be used to limit the scope of the present invention.

[0006] Beneficial effects of the present invention:

[0007] (1) The present invention provides a general method for modifying the ligand skeleton, which does not require purification methods such as column chromatography / recrystallization, and can simply and efficiently synthesize a series of α-diimine ligands with different skeleton modifications in a one-pot method, and prepare the corresponding Ni(II) catalyst. The synthesized Ni catalyst is used to achieve a large-scale regulation of the polymerization reaction and the polymerization product by adjusting the ligand structure, polymerization temperature, ethylene pressure, etc.: the polymer molecular weight (M w range 14.9~647.7kDa); branching degree (polymer branching range <1~126.9 / 1000C); thermal stability (polymerization limit temperature increased to 150℃); catalytic activity (based on the activity, the activity can reach up to 2×10 8 gmol -1 h -1 ).

[0008] (2) The general method of ligand skeleton modification of the present invention is to modify the classic Brookhart type α-diimine ligand skeleton, without the need for purification methods such as column chromatography / recrystallization, and to simply and efficiently synthesize a series of α-diimine ligands with different skeleton modifications in a one-pot method, and prepare the corresponding Ni(II) catalysts, and it is confirmed that this series of skeleton-modified α-diimine nickel catalysts have significant improvements in catalyzing ethylene polymerization; this general method overcomes the problem of complex synthesis of new skeletons, achieves a balance between the simplicity of chemical synthesis methods and catalytic effects, and obtains a series of catalysts with outstanding polymerization effects through a simple and efficient synthesis method; the thermal stability of this type of nickel catalyst is significantly improved, and under certain temperature / ethylene pressure conditions, a wide range of regulation can be achieved in terms of catalytic activity, polymer molecular weight, branching density, and branching type. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] In order to more clearly illustrate the technical solution of the embodiment of the present invention, the following is a brief introduction to the drawings required for describing the embodiment. Among them:

[0010] Figure 1 This is the hydrogen nuclear magnetic resonance spectrum of the skeleton-modified α-diimine nickel ligand in Example 1 of the present invention.

[0011] Figure 2 This is the carbon NMR spectrum of the skeleton-modified α-diimine nickel ligand in Example 1 of the present invention.

[0012] Figure 3 The NMR of the skeleton-modified α-diimine nickel ligand in Example 1 of the present invention is 1 H- 1 H COSY 2D NMR spectrum.

[0013] Figure 4 The NMR of the skeleton-modified α-diimine nickel ligand in Example 1 of the present invention is1 H- 13 CHSQC 2D NMR spectrum.

[0014] Figure 5 This is the MALDI-TOF mass spectrum of the skeleton-modified α-diimine nickel ligand in Example 1 of the present invention.

[0015] Figure 6 This is the MALDI-TOF mass spectrum of the skeleton-modified α-diimine nickel catalyst in Example 17 of the present invention.

[0016] Figure 7 This is the single crystal diffraction pattern of the framework-modified α-diimine nickel catalyst in Example 17 of the present invention.

[0017] Figure 8 Graphs showing changes in polymerization reaction parameters in an embodiment of the present invention; wherein, (a) is a graph showing changes in 20L kettle pressure during the polymerization reaction in an embodiment of the present invention, (b) is a graph showing changes in total ethylene consumption during the polymerization reaction in an embodiment of the present invention, and (c) is a graph showing changes in temperature data during the polymerization reaction in an embodiment of the present invention.

[0018] Fig. 9 It is a polymerization reaction kettle process and polymer recording diagram in an embodiment of the present invention. DETAILED DESCRIPTION

[0019] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the embodiments of the specification.

[0020] In the examples of the present invention, except for the basic ligand N,N'-bis(2,6-dimethylphenyl)butane-2,3-diimide (synthesized by referring to J. Am. Chem. Soc. 1995, 117, 6414), all the raw materials involved are commercially available.

[0021] Example 1

[0022] Preparation of ligand L18:

[0023]

[0024] Under an inert atmosphere (nitrogen), N,N'-bis(2,6-dimethylphenyl)butane-2,3-diimine (0.60 g, 2.1 mmol) was dissolved in pentane (20 mL), and then n-butyllithium ( nA 1:1 mixed solution of BuLi (1.6M, 2.6mL, 4.2mmol) and tetramethylethylenediamine (TMEDA, 0.6mL, 4.2mmol) was gradually added dropwise to the pentane solution, and the color of the solution gradually deepened. At the beginning of the addition, the solution quickly changed from yellow to red. After 1 / 2 of the mixed lithium reagent was added, the entire reaction system became an orange turbid liquid. After all the additions were completed, the mixture was stirred at room temperature overnight.

[0025] After the reaction was completed, the reaction solution finally showed a yellow turbid liquid. 2-(Bromomethyl)naphthalene (0.9 g, 4.2 mmol) was dissolved in pentane (2 mL) and then added dropwise to the reaction system. After all the addition was completed, the mixture was heated to reflux for 24 hours.

[0026] After the reaction is completed, the mixture is cooled to room temperature (20-25°C), stirred and washed with water three times, and then the organic layer is collected and concentrated by vacuum rotary evaporation to obtain an orange crude product.

[0027] The crude product was purified by cold hexane, the solid was separated by filtration and dried under vacuum to obtain the target product ligand L18, and 0.94 g (87% yield) of yellow powder solid was obtained. The H NMR spectrum of the skeleton-modified α-diimine nickel ligand is shown in Figure 1 ; The carbon NMR spectrum of the skeleton-modified α-diimine nickel ligand is shown in Figure 2 ; NMR of framework-modified α-diimine nickel ligand 1 H- 1 H COSY 2D NMR spectrum see Figure 3 ; NMR of framework-modified α-diimine nickel ligand 1 H- 13 C HSQC 2D NMR spectrum see Figure 4 ; MALDI-TOF mass spectrum of framework-modified α-diimine nickel ligands can be found in Figure 5 .

[0028] 1 H NMR (500MHz, 298K, CDCl3, 7.26ppm): δ = 7.75 (d, 2H, Nap-H, J = 8.8Hz), 7.67 (d, 4H, Nap-H, J = 8.2Hz), 7.45–7.36 (m, 6H, Nap-H, ary l-H),7.12(d,J=7.4Hz,6H,Nap-H,aryl-H),7.04–6.99(m,2H,aryl-H),2.98(d,8H,CH2,J=6.4Hz,),2.10(s,12H,aryl-Me)ppm.

[0029] 13C NMR (125MHz, 298K, CDCl3, 77.16ppm): δ = 170.05 (N = C-Me), 148.35, 138.71, 133.62, 132.22, 128.35, 128.20, 12 7.69,127.53,127.04,126.40,126.09,125.43,124.84,123.61,33.22(CH2),31.53(CH2),18.51(aryl-Me)ppm.

[0030] Elemental analysis:Anal.Calcd for C 40 H 40 N2:C,88.07;H,7.04;N,4.89.Found:C,88.10;H,7.02;N,4.88.

[0031] MALDI-TOF MS:Calcd for C 40 H 40 N2:572.32.Found:572.3[M] + .

[0032] Synthesis of some framework-modified ligands Except for the different reactant B, all other operations were the same as described in Example 1 (the feed ratio of reactant A: reactant B was 1:3, the reaction temperature was 35° C., and the reaction time was 48 h), as shown in Table 1 below.

[0033] Reactant A:

[0034] Table 1

[0035]

[0036]

[0037] Note: Except for reactant B in sequence number 19, which was synthesized according to literature reference 10.1016 / j.jorganchem.2022.122430, all reactant B raw materials in Table 1 can be purchased from Anaiji Chemical or other reagent suppliers.

[0038] Example 2

[0039] Structural characterization of ligand L1:

[0040] 11H NMR (500 MHz, 298 K, CDCl3, 7.26 ppm): δ = 7.19 (t, 4H, aryl-H, J = 7.2 Hz), 7.14 (d, 2H, aryl-H, J = 7.1 Hz), 7.10 (d, 4H, aryl-H, J = 7.4 Hz), 6.99 (dd 6H, aryl-H, J = 17.9, 7.5 Hz), 2.89 - 2.78 (m, 8H, CH2), 2.07 (s, 12H, aryl-Me) ppm.

[0041] Elemental analysis: Anal. Calcd for C 34 H 36 N2: C, 86.40; H, 7.68; N, 5.93. Found: C, 86.35; H, 7.71; N, 5.94.

[0042] MALDI-TOF MS: Calcd for C 34 H 36 N2: 472.29. Found: 472.3 [M] + .

[0043] Example 3

[0044] Structural characterization of ligand L2:

[0045] 1 1H NMR (500 MHz, 298 K, CDCl3, 7.26 ppm): δ = 7.11 (d, 4H, aryl-H, J = 7.0 Hz), 6.99 (t, 2H, aryl-H, J = 7.5 Hz), 6.96 - 9.90 (m, 4H, aryl-H), 6.86 (t, 4H, aryl-H, J = 8.5 Hz), 2.79 (d, 8H, CH2, J = 7.0 Hz), 2.07 (s, 12H, aryl-Me) ppm.

[0046] Elemental analysis: Anal. Calcd for C 34 H 34 F2N2: C, 80.28; H, 6.74; N, 5.51. Found: C, 80.32; H, 6.71; N, 5.49.

[0047] MALDI-TOF MS: Calcd for C 34 H 34 F2N2: 508.27. Found: 508.3 [M] + .

[0048] Example 4

[0049] Structural characterization of ligand L3:

[0050] 1 H NMR (500MHz, 298K, CDCl3, 7.26ppm): δ = 7.09 (d, 4H, aryl-H, J = 7.4Hz), 6.97 (t, 2H, aryl-H, J = 7.5Hz,), 6.91 (d, 4H, aryl-H, J = 8.2Hz) ,6.73(d,4H,aryl-H,J=8.2Hz),3.74(s,6H,OCH3),2.78(d,4H,J=8.7Hz,CH2),2.75(d,4H,J=8.7Hz,CH2),2.07(s,12H,aryl-Me)ppm.

[0051] Elemental analysis:Anal.Calcd for C 36 H 40 N2O2:C,81.17;H,7.57;N,5.26.Found:C,81.20;H,7.55;N,5.28.

[0052] MALDI-TOF MS:Calcd for C 36 H 40 N2O2:532.31.Found:532.3[M] + .

[0053] Example 5

[0054] Structural characterization of ligand L4:

[0055] 1 H NMR (500MHz, 298K, CDCl3, 7.26ppm): δ = 7.21 (d, 4H, aryl-H, J = 8.0Hz), 7.08 (d, 4H, aryl-H, J = 7.4Hz), 6.96 (dd, 6H, aryl-H ,J=13.6,7.7Hz),2.84(d,4H,CH2,J=10.0Hz),2.82–2.77(m,4H,CH2),2.05(s,12H,aryl-Me),1.26(s,18H,C(CH3)3)ppm.

[0056] Elemental analysis:Anal.Calcd for C 42 H 52N2:C,86.25;H,8.96;N,4.79.Found:C,86.20;H,8.92;N,4.88.

[0057] MALDI-TOF MS:Calcd for C 42 H 52 N2:584.81.Found:584.4[M] + .

[0058] Example 6

[0059] Structural characterization of ligand L5:

[0060] 1 H NMR (500MHz, 298K, CDCl3, 7.26ppm): δ = 7.52 (d, 4H, aryl-H, J = 7.4Hz), 7.45–7.38 (m, 8H, aryl-H), 7.31 (t, 2H, aryl-H, J = 6.7 Hz),7.10(dd,8H,aryl-H,J=17.2,7.8Hz),6.99(t,2H,aryl-H,J=7.5Hz),2.95–2.83(m,8H,CH2),2.10(s,12H,aryl-Me)ppm.

[0061] Elemental analysis:Anal.Calcd for C 46 H 44 N2:C,88.42;H,7.10;N,4.48.Found:C,88.45;H,7.08;N,4.47.

[0062] MALDI-TOF MS:Calcd for C 46 H 44 N2:624.35.Found:624.4[M] + .

[0063] Example 7

[0064] Structural characterization of ligand L6:

[0065] 11H NMR (500 MHz, 298 K, CDCl3, 7.26 ppm): δ = 7.08 (d, 6H, aryl-H, J = 6.2 Hz), 7.02–6.94 (m, 6H, aryl-H), 6.91 (d, 4H, aryl-H, J = 6.0 Hz), 2.86–2.75 (m, 8H, CH2), 2.55–2.49 (m, 4H, nBu-CH2), 2.06 (s, 12H, aryl-Me), 1.54 (d, 8H, nBu-CH2, J = 14.6 Hz), 1.35–1.29 (m, 4H, nBu-CH2), 0.89 (s, 6H, nBu-CH3) ppm.

[0066] Elemental analysis: Anal. Calcd for C 42 H 52 N2: C, 86.25; H, 8.96; N, 4.79. Found: C, 86.21; H, 8.99; N, 4.80.

[0067] MALDI-TOF MS: Calcd for C 42 H 52 N2: 584.81. Found: 584.4 [M] + .

[0068] Example 8

[0069] Structural characterization of ligand L7:

[0070] 1 1H NMR (500 MHz, 298 K, CDCl3, 7.26 ppm): δ = 7.43 (d, 2H, aryl-H, J = 8.0 Hz,), 7.12 (d, 2H, aryl-H, J = 7.5 Hz), 7.08 (d, 4H, aryl-H, J = 8.0 Hz), 7.00 (t, 2H, aryl-H, J = 7.5 Hz), 2.85 (m, 8H, CH2), 2.06 (s, 12H, aryl-Me) ppm.

[0071] Elemental analysis: Anal. Calcd for C 36 H 34 F6N2: C, 71.04; H, 5.63; N, 4.60. Found: C, 71.00; H, 5.66; N, 4.60.

[0072] MALDI-TOF MS: Calcd for C 36 H34 F6N2:608.26.Found:433.2[M-CH2PhCF3] + .

[0073] Example 9

[0074] Structural characterization of ligand L9:

[0075] 1 H NMR (500MHz, 298K, CDCl3, 7.26ppm): δ = 7.09 (d, 4H, aryl-H, J = 7.5Hz), 7.00 (d, 4H, aryl-H, J = 7.8Hz), 6.96 (d, 2H, aryl-H, J = 7.5Hz), 6. 90(d,4H,aryl-H,J=7.8Hz),2.86–2.74(m,8H,CH2),2.27(s,6H,aryl-Me),2.07(s,12H,aryl-Me)ppm.Elemental analysis:Anal.Calcd for C 36 H 40 N2:C,86.35;H,8.05;N,5.59.Found:C,86.31;H,8.09;N,5.60.

[0076] MALDI-TOF MS:Calcd for C 36 H 40 N2:500.32.Found:500.3[M] + .

[0077] Example 10

[0078] Structural characterization of ligand L10:

[0079] 1 H NMR (500MHz, 298K, CDCl3, 7.26ppm): δ = 7.09 (d, 4H, aryl-H, J = 7.5Hz), 6.99–6.93 (m, 2H, aryl-H), 6.72 (s, 4H, aryl-H), 2.76 ( d,4H,CH2,J=16.7Hz),2.65(d,4H,CH2,J=16.5Hz),2.18(s,6H,aryl-Me),2.13(s,12H,aryl-Me),1.96(s,12H,aryl-Me)ppm.

[0080] Elemental analysis:Anal.Calcd for C 39 H 46N2:C,86.30;H,8.54;N,5.16.Found:C,86.31;H,8.57;N,5.12.

[0081] MALDI-TOF MS:Calcd for C 39 H 46 N2:556.38.Found:556.4[M] + .

[0082] Embodiment 11

[0083] Structural characterization of ligand L12:

[0084] 1 H NMR (500MHz, 298K, CDCl3, 7.26ppm): δ = 7.09 (d, 6H, aryl-H, J = 7.4Hz), 7.00 (d, 2H, aryl-H, J = 7.3Hz), 6.97 ( t,4H,aryl-H,J=6.8Hz),6.91(t,2H,aryl-H,J=9.0Hz),2.95–2.81(m,8H,CH2),2.07(s,12H,aryl-Me)ppm.

[0085] Elemental analysis:Anal.Calcd for C 34 H 34 F2N2:C,80.28;H,6.74;N,5.51.Found:C,84.32;H,6.71;N,5.52.

[0086] MALDI-TOF MS:Calcd for C 34 H 34 F2N2:508.27.Found:508.3[M] + .

[0087] Example 12

[0088] Structural characterization of ligand L13:

[0089] 11H NMR (500 MHz, 298 K, CDCl3, 7.26 ppm): δ = 7.12 (t, 2H, aryl-H, J = 7.6 Hz), 7.07 (d, 4H, aryl-H, J = 7.5 Hz), 7.00 (d, 2H, aryl-H, J = 7.3 Hz), 6.94 (t, 2H, aryl-H, J = 7.5 Hz), 6.78 (t, 2H, aryl-H, J = 7.3 Hz), 6.72 (d, 2H, aryl-H, J = 8.1 Hz), 3.55 (s, 6H, OMe), 2.88 (d, 4H, CH2, J = 8.9 Hz), 2.82 (d, 4H, CH2, J = 9.1 Hz), 2.08 (s, 12H, aryl-Me) ppm.

[0090] Elemental analysis: Anal. Calcd for C 36 H 40 N2O2: C, 81.17; H, 7.57; N, 5.26. Found: C, 81.19; H, 7.54; N, 5.28.

[0091] MALDI-TOF MS: Calcd for C 36 H 40 N2O2: 532.21. Found: 532.3 [M] + .

[0092] Example 13

[0093] Structural characterization of ligand L14:

[0094] 1 1H NMR (500 MHz, 298 K, CDCl3, 7.26 ppm): δ = 7.22–7.11 (m, 12H, aryl-H), 7.09 (d, 2H, aryl-H, J = 8.8 Hz), 7.03 (d, 4H, aryl-H, J = 7.4 Hz), 6.97 (dd, 6H, aryl-H, J = 18.0, 8.6 Hz), 2.70 (m, 8H, CH2), 1.82 (s, 12H, aryl-Me) ppm.

[0095] Elemental analysis: Anal. Calcd for C 46 H 44 N2: C, 88.42; H, 7.10; N, 4.48. Found: C, 88.46; H, 7.09; N, 4.45.

[0096] MALDI-TOF MS:Calcd for C 46 H 44 N2:624.35.Found:624.4[M] + .

[0097] Embodiment 14

[0098] Structural characterization of ligand L15:

[0099] 1 H NMR (500MHz, 298K, CDCl3, 7.26ppm): δ = 7.51 (d, 2H, aryl-H, J = 7.9Hz), 7.37 (t, 2H, aryl-H, J = 7.5Hz), 7.25–7.20 (m, 4H, aryl-H), 7.11 ( d,4H,aryl-H,J=7.4Hz),6.98(t,2H,aryl-H,J=7.5Hz),3.01(d,4H,CH2,J=16.1Hz),2.89–2.82(m,4H,CH2),2.11(s,12H,aryl-Me)ppm.

[0100] Elemental analysis:Anal.Calcd for C 36 H 34 F6N2:C,71.04;H,5.63;N,4.60.Found:C,71.00;H,5.66;N,4.62.

[0101] MALDI-TOF MS:Calcd for C 36 H 34 F6N2:608.26.Found:432.3[M-CH2PhCF3] + .

[0102] Embodiment 15

[0103] Structural characterization of ligand L16:

[0104] 1 H NMR (500MHz, 298K, CDCl3, 7.26ppm): δ=7.16–7.05(m,4H,aryl-H),7.03–6.96(m,2H,aryl -H), 2.94 (d, 4H, CH2, J = 14.7Hz), 2.81 (d, 4H, CH2, J = 14.7Hz), 2.05 (s, 12H, aryl-Me) ppm.

[0105] Elemental analysis:Anal.Calcd for C 34 H 26 F 10 N2:C,62.58;H,4.02;N,4.29.Found:C,62.61;H,4.04;N,4.32.

[0106] MALDI-TOF MS:Calcd for C 34 H 26 F 10 N2:652.19.Found:653.2[M+H] + .

[0107] Example 16

[0108] Structural characterization of ligand L17:

[0109] 1 H NMR (500MHz, 298K, CDCl3, 7.26ppm): δ = 7.42 (d, 2H, aryl-H, J = 7.3Hz), 7.32 (d, 2H, aryl-H, J = 7.8Hz), 7.22–7.12 (m, 4H, aryl-H), 7.06 (d, 4H, aryl -H,J=7.4Hz),6.96(t,2H,aryl-H,J=7.4Hz),6.26(s,2H,C=CH),3.08(d,4H,CH2,J=7.4Hz),3.01(d,4H,CH2,J=7.5Hz,,2.00(s,12H,aryl-Me)ppm.

[0110] Elemental analysis:Anal.Calcd for C 38 H 36 N2O2:C,82.58;H,6.57;N,5.07.Found:C,82.61;H,6.56;N,5.04.

[0111] MALDI-TOF MS:Calcd for C 38 H 36 N2O2:552.28.Found:552.3[M] + .

[0112] Embodiment 17

[0113] Preparation of catalyst Ni17:

[0114]

[0115] The reactant A ligand L18 (0.35 mmol) and the reactant B (DME) NiBr2 (0.35 mmol) were dissolved in 30 ml of dichloromethane and stirred at 25°C for 24 hours to obtain a dark red liquid. After evaporating the solvent in vacuo, an orange solid was obtained. The solid was washed three times with n-hexane, filtered, and finally washed three times with ether. The orange solid was dried under vacuum to obtain a pure nickel complex (97.4% yield). The MALDI-TOF mass spectrum of the skeleton-modified α-diimine nickel catalyst is shown in Figure 6 ; The single crystal diffraction pattern of the framework-modified α-diimine nickel catalyst is shown in Figure 7 .

[0116] Elemental analysis:Anal.Calcd for C 42 H 40 Br2N2Ni:C,63.75;H,5.10;N,3.54.Found:C,63.70;H,5.11;N,3.57.

[0117] MALDI-TOF MS:Calcd for C 42 H 40 Br2N2Ni:788.09.Found:572.3[M-Ni-2Br] + .

[0118] Embodiment 18

[0119] Different nickel catalysts (changing the substituent R 7 , R 8 ) on ethylene polymerization.

[0120] Reaction conditions: Nickel catalyst (1 μmol, R 3 =R 6 =H,R 1 =R 2 =R 4 =R 5 =Me), MAO (methylaluminoxane, 750 μmol), hydrocarbon solvent isopar-E or n-hexane / dichloromethane or chloroform (98 mL / 2 mL), ethylene pressure (8 atmospheres), polymerization time (30 minutes), polymerization temperature (90°C), all data are based on the results of at least two parallel experiments (unless otherwise stated).

[0121] Activity: 10 6 gmol -1 h -1 As unit.

[0122] M w 、Mw / M n : weight average molecular weight and polymer molecular weight distribution index, respectively, measured by GPC in 1,2,4-trichlorobenzene at 150°C, relative to polystyrene standards. Degree of branching = number of branches per 1000 carbon atoms, measured by proton nuclear magnetic resonance spectroscopy.

[0123] Polymerization reaction process: first, a 350 mL glass pressure reactor connected to a high-pressure gas pipeline was vacuum dried at 90°C for at least 1 hour, then the reactor was adjusted to 90°C, 98 mL of hydrocarbon solvent isopar-E and 750 μmol of MAO were added to the reactor under an inert atmosphere, and then 1 μmol of Ni catalyst was dissolved in 2 mL of dichloromethane (or chloroform) and injected into the polymerization system through a syringe;

[0124] Under rapid stirring (more than 600 rpm), ethylene was introduced and maintained at 8 bar; after 30 minutes, the pressure reactor was evacuated, a large amount of acidic acetone (more than 5% hydrochloric acid acetone solution) was added, the polymer was filtered, and dried in a vacuum oven to constant weight.

[0125] At a polymerization temperature of 90°C, while keeping all polymerization conditions the same, the polymerization activity of the Ni17 catalyst increased by 2 times compared to before modification, the polymer molecular weight increased significantly by 3 times, and the polymer branching degree decreased.

[0126] Some nickel catalysts (Change the substituent R 7 , R 8 ) was synthesized with the exception of reactant A, and all other operations were the same as described in Example 17 (the feed ratio of reactant A: reactant B was 1:1, the reaction temperature was 25° C., and the reaction time was 24 h). The specific synthesis results are shown in Table 2.

[0127] Table 2

[0128]

[0129]

[0130]

[0131] Different nickel catalysts at high temperature (90℃) and normal pressure (Change the substituent R 7 , R 8 ) on ethylene polymerization (polymerization operation is the same as described in Example 18) see Table 3.

[0132] Table 3

[0133]

[0134] Conclusion of polymerization data: When the catalyst substituent R is controlled 1 , R 2 , R 3 , R 4 , R 5 , R 6 If the value remains unchanged, change the substituent R 7 , R 8 When the polymerization conditions are the same (time, temperature, pressure, and catalyst concentration are the same), When n=1, the maximum molecular weight of the polymer is 100.7 kDa. The highest activity (8.66×10 6 gmol -1 h -1 ). Among them, when R 8 Electron-donating groups (CH3, OCH3) have higher activity than electron-withdrawing groups (F, CF3, NO2). 8 If R 8 Located in the ortho position of the phenyl group, the catalyst can obtain higher polymer molecular weight and polymerization activity. 7 The greater the steric hindrance, the higher the activity and molecular weight of the obtained polymer (anthracene ring>naphthalene ring>methyl ring).

[0135] Embodiment 19

[0136] Different nickel catalysts (changing the substituent R 7 , R 8 ) on ethylene polymerization:

[0137] Reaction conditions: catalyst (1 μmol, R 3 =R 6 =H,R 1 =R 2 =R 4 =R 5 =Me), MAO (methylaluminoxane, 750 μmol), hydrocarbon solvent isopar-E or n-hexane / dichloromethane or chloroform (98 mL / 2 mL), ethylene pressure (8 atmospheres), polymerization time (30 minutes), polymerization temperature (110°C), all data are based on the results of at least two parallel experiments (unless otherwise stated).

[0138] Activity: 10 6 gmol -1 h -1 The unit is M w 、M w / M n: weight average molecular weight, polymer dispersity index, respectively, measured by GPC in 1,2,4-trichlorobenzene at 150°C, relative to polystyrene standards. Degree of branching = number of branches per 1000 carbon atoms, measured by proton nuclear magnetic resonance spectroscopy.

[0139] Polymerization reaction process: first, a 350 mL glass pressure reactor connected to a high-pressure gas pipeline was vacuum dried at 90 ° C for at least 1 hour, and then the reactor was adjusted to 110 ° C, 98 mL hydrocarbon solvent isopar-E and 750 μmol of MAO were added to the reactor under an inert atmosphere, and then 1 μmol of Ni catalyst was dissolved in 2 mL of dichloromethane (or chloroform) and injected into the polymerization system through a syringe;

[0140] Under rapid stirring (more than 600 rpm), ethylene was introduced and maintained at 8 bar. After 30 minutes, the pressure reactor was evacuated, a large amount of acidic acetone (more than 5% hydrochloric acid acetone solution) was added, the polymer was filtered, and dried in a vacuum oven to constant weight.

[0141] Different nickel catalysts at high temperature (110℃) and normal pressure (Change the substituent R 7 , R 8 ) on ethylene polymerization (polymerization operation is the same as described in Example 19) see Table 4.

[0142] Table 4

[0143]

[0144]

[0145] Conclusion of polymerization data: When the catalyst substituent R is controlled 1 , R 2 , R 3 , R 4 , R 5 , R 6 If the value remains unchanged, change the substituent R 7 , R 8 When the polymerization conditions are the same (time, temperature, pressure, and catalyst concentration are the same), When The highest activity (6.48×10 6 gmol -1 h -1 ).

[0146] Among them, when R 8 Electron-donating groups (CH3, OCH3) have higher activity than electron-withdrawing groups (F, CF3, NO2).8 If R 8 Located in the ortho position of the phenyl group, the catalyst can obtain higher polymer molecular weight and polymerization activity. 7 The greater the steric hindrance, the higher the activity and molecular weight of the obtained polymer (anthracene ring>naphthalene ring>methyl ring).

[0147] Embodiment 20

[0148] Preparation of [(CH2Ph)N^N)]NiBr2 catalyst Ni1:

[0149] The ligand L1 (0.2 mmol) and (DME) NiBr2 (0.2 mmol) were dissolved in 30 ml of dichloromethane, stirred at 25°C for 24 hours to obtain a dark red liquid, and the solvent was evaporated in vacuo to obtain an orange solid, which was washed three times with n-hexane, filtered, and finally washed three times with ether. The orange solid was dried under vacuum to obtain a pure nickel complex (95.9% yield). The preparation process of catalysts Ni2-Ni16 is the same, and the results of elemental analysis and mass spectrometry characterization of the catalysts are shown in Table 2.

[0150] Embodiment 21

[0151] Different nickel catalysts (changing the substituent R 3 , R 6 ) on ethylene polymerization:

[0152] Reaction conditions: Nickel catalyst (1 μmol, R 1 =R 2 =R 4 =R 5 =Me, ), MAO (methylaluminoxane, 750 μmol), hydrocarbon solvent isopar-E or n-hexane / dichloromethane or chloroform (98 mL / 2 mL), ethylene pressure (8 atmospheres), polymerization time (30 minutes), polymerization temperature (90 ° C), all data are based on at least two parallel tests (unless otherwise stated). Activity: 10 6 gmol -1 h -1 For units;

[0153] M w 、M w / M n : weight average molecular weight, polymer dispersity index, respectively, measured by GPC in 1,2,4-trichlorobenzene at 150°C, relative to polystyrene standards. Degree of branching = number of branches per 1000 carbon atoms, measured by proton nuclear magnetic resonance spectroscopy.

[0154] Polymerization reaction process: first, a 350 mL glass pressure reactor connected to a high-pressure gas pipeline was vacuum dried at 90 ° C for at least 1 hour, and then the reactor was adjusted to 90 ° C, 98 mL of hydrocarbon solvent isopar-E and 750 μmol of MAO were added to the reactor under an inert atmosphere, and then 1 μmol of Ni catalyst was dissolved in 2 mL of dichloromethane (or chloroform) and injected into the polymerization system through a syringe.

[0155] Under rapid stirring (more than 600 rpm), ethylene was introduced and maintained at 8 bar. After 30 minutes, the pressure reactor was evacuated and a large amount of acidic acetone (more than 5% hydrochloric acid acetone solution) was added to quench the polymerization reaction. The polymer was filtered and dried in a vacuum oven to constant weight.

[0156] Different nickel catalysts (Synthesis of nickel catalyst except reactant A is different process and all other operations are the same as Example 20, change the substituent R 3 , R 6 ), the feed ratio of reactant A: reactant B is 1:1, the reaction temperature is 25°C, the reaction time is 24h, and the specific synthesis results are shown in Table 5.

[0157] Table 5

[0158]

[0159]

[0160] Different nickel catalysts at high temperature (90℃) and normal pressure The effect on ethylene polymerization (polymerization operation is the same as described in Example 21) is shown in Table 6.

[0161] Table 6

[0162]

[0163]

[0164] Conclusion of polymerization data: When the catalyst substituent R is controlled 1 , R 2 , R 4 , R 5 , R 7 , R 8 If the value remains unchanged, change the substituent R 3 , R 6 When R 3 =R 6 =N(CH3)2, the polymer has the highest molecular weight (M w 79.7 kDa);

[0165] When R 3 =R 6 = t When Bu, the polymer activity reached the highest (4.22×10 6 gmol -1 h -1 ). When changing the substituent R 3 , R 6 When the polymerization conditions are the same (time, temperature, pressure, and catalyst concentration are the same), in addition, electron-withdrawing groups (F, Cl, CF3, NO2) will lead to a decrease in polymer molecular weight and activity, while electron-donating groups are beneficial to increasing polymer activity and molecular weight ( t Bu, OCH3, N(CH3)2).

[0166] Embodiment 22

[0167] Different nickel catalysts (changing the substituent R 1 , R 2 , R 4 , R 5 ) on ethylene polymerization:

[0168] Reaction conditions: Nickel catalyst (1 μmol, R 3 =R 6 =H, ), MAO (methylaluminoxane, 750 μmol), hydrocarbon solvent isopar-E or n-hexane / dichloromethane or chloroform (98 mL / 2 mL), ethylene pressure (8 atmospheres), polymerization time (30 minutes), polymerization temperature (90°C), all data are based on the results of at least two parallel experiments (unless otherwise stated).

[0169] Activity: 10 6 gmol -1 h -1 The unit is M w 、M w / M n : weight average molecular weight, polymer dispersity index, respectively, measured by GPC in 1,2,4-trichlorobenzene at 150°C, relative to polystyrene standards. Degree of branching = number of branches per 1000 carbon atoms, measured by proton nuclear magnetic resonance spectroscopy.

[0170] Polymerization process: First, a 350mL glass pressure reactor connected to a high-pressure gas pipeline is vacuum dried at 90°C for at least 1 hour, then the reactor is adjusted to 90°C, 98mL hydrocarbon solvent isopar-E and 750μmol of MAO are added to the reactor under an inert atmosphere, and then 1μmol of Ni catalyst is dissolved in 2mL of dichloromethane (or chloroform) and injected into the polymerization system through a syringe. Under rapid stirring (more than 600 revolutions), ethylene is introduced and maintained at 8bar. After 30 minutes, the pressure reactor is emptied, a large amount of acidic acetone (more than 5% hydrochloric acid acetone solution) solution is added to quench the polymerization reaction, the polymer is filtered, and dried in a vacuum oven to constant weight.

[0171] Different nickel catalysts (Synthesis of nickel catalyst except reactant A is different process and all other operations are the same as Example 20, change the substituent R 1 , R 2 , R 4 , R 5 ), the feed ratio of reactant A: reactant B is 1:1, the reaction temperature is 25°C, the reaction time is 24h, and the specific synthesis results are shown in Table 7.

[0172] Table 7

[0173]

[0174]

[0175] Different nickel catalysts at high temperature (90℃) and normal pressure (Change the substituent R 1 , R 2 , R 4 , R 5 ) on ethylene polymerization (polymerization operation is the same as described in Example 22) see Table 8.

[0176] See Table 8 for the results.

[0177] Table 8

[0178]

[0179]

[0180] It can be seen from Table 8 that when the catalyst substituent R 3 , R 4 , R 7 No change, change the substituent R 3 , R 6 , R 8 When R 1=R 2 =R 4 =R 5 = diphenylmethyl series (CHPh2), the catalyst activity and polymer molecular weight are the highest, and the polymer branching degree is the lowest. This is determined by the base ligand of the catalyst before modification. This shows that the skeleton-modified catalyst can further improve the performance of the catalyst (catalytic activity, polymer molecular weight) in addition to retaining the catalytic properties unique to the original catalyst type, and also verifies the universality of the skeleton modification method.

[0181] Embodiment 23

[0182] The ligand L18 (0.4 mmol) and Ni(acac)2 (acac = acetylacetone) and [Ph3C][B(C6F5)4] were dissolved in dichloromethane in a ratio of 1:1:1. The mixture was stirred at room temperature (25°C) for more than 12 hours, and then the solvent was evaporated by rotary evaporation. The solid was washed with n-hexane and ether, filtered and separated, washed three times with hexane and ether respectively, and dried under vacuum to obtain pure catalyst Ni35 with a yield of 78.9%.

[0183]

[0184] Elemental analysis:Anal.Calcd for C 71 H 71 N2O 20 O2:C,63.06;H,3.70;N,1.77.Found:C,63.01;H,3.74;N,1.78.

[0185] Embodiment 24

[0186] Effects of different polymerization conditions on ethylene polymerization catalyzed by different α-diimine nickel catalysts:

[0187] Reaction conditions: Nickel catalyst (1 μmol, R 1 =R 2 =R 4 =R 5 =CH3,R 3 =R 6 =H), MAO (methylaluminoxane, 750 μmol), hydrocarbon solvent isopar-E or n-hexane / dichloromethane or chloroform (98 mL / 2 mL), ethylene pressure (8-20 atmospheres), polymerization time (1.5-30 minutes), polymerization temperature (30-150°C), all data are based on at least two parallel tests (unless otherwise stated);

[0188] Activity: 10 6 gmol-1 h -1 The unit is M w 、M w / M n : weight average molecular weight, polymer dispersity index, respectively, measured by GPC in 1,2,4-trichlorobenzene at 150°C, relative to polystyrene standards. Degree of branching = number of branches per 1000 carbon atoms, measured by proton nuclear magnetic resonance spectroscopy.

[0189] Polymerization process: First, a 350 mL glass pressure reactor connected to a high-pressure gas pipeline is vacuum dried at 90°C for at least 1 hour, then the reactor is adjusted to the corresponding polymerization temperature (30-150°C), 98 mL hydrocarbon solvent isopar-E and 750 μmol of MAO are added to the reactor under an inert atmosphere, and then 1 μmol of Ni catalyst is dissolved in 2 mL of dichloromethane (or chloroform) and injected into the polymerization system through a syringe. Under rapid stirring (more than 600 revolutions), ethylene is introduced and maintained at a corresponding pressure (8-20 bar). After the corresponding polymerization time (1.5-30 minutes), the pressure reactor is emptied, a large amount of acidic acetone (more than 5% hydrochloric acid acetone solution) solution is added to quench the polymerization reaction, the polymer is filtered, and dried in a vacuum oven to constant weight.

[0190] Different nickel catalysts under different polymerization conditions (temperature, ethylene pressure) The effect on ethylene polymerization (polymerization operation is the same as described in Example 24) is shown in Table 9.

[0191] Table 9

[0192]

[0193]

[0194] It can be seen that when the pressure (8 bar) and time (30 min) are kept constant, the activity and molecular weight of the polymer produced by the nickel catalyst decrease with increasing temperature, and the degree of branching increases significantly with increasing temperature; when the temperature is kept constant (90°C), the activity and molecular weight of the polymer produced by the nickel catalyst increase with increasing ethylene pressure, and the degree of branching decreases significantly with increasing ethylene pressure.

[0195] When using When nickel dibromide is used as catalyst, the activity can reach up to 200.80×10 6 gmol -1 h -1By adjusting each polymerization condition to the limit value, that is, lowering the polymerization temperature to 0°C and increasing the ethylene pressure to 48 bar, the polymer molecular weight can reach up to 647.7 kDa, and the lowest branching degree can reach <1 / 1000C.

[0196] Embodiment 25

[0197] Ethylene polymerization using nickel catalyst Ni13 in a 20L polymerization reactor:

[0198] Reaction conditions: nickel catalyst (100 μmol), Et2AlCl (diethylaluminum chloride, Anaiji Chemical, 1.0 mol / lin hexane, EnergySeal, 750 μmol), Bu2Mg (dibutylmagnesium, Anaiji Chemical, 1.0 mol / l in hexane, EnergySeal, 300 μmol), hydrocarbon solvent n-hexane / dichloromethane or chloroform (10 L / 50 mL), ethylene pressure (1-28 atmospheres), polymerization time (60 minutes), polymerization temperature (20-30°C), all data are based on at least two parallel tests (unless otherwise stated);

[0199] Activity: 10 6 gmol -1 h -1 The unit is M w 、M w / M n : weight average molecular weight, polymer dispersity index, respectively, measured by GPC in 1,2,4-trichlorobenzene at 150°C, relative to polystyrene standards. Degree of branching = number of branches per 1000 carbon atoms, measured by proton nuclear magnetic resonance spectroscopy.

[0200] Polymerization process: The polymerization reactor is cleaned, vacuum dried at 150°C, and then returned to room temperature. 10L of polymerization solvent hexane is added, and after the reactor temperature is balanced to about 25°C, a co-catalyst (75mL of 1.0M Et2AlCl hexane solution and 30mL of 1.0M Bu2Mg hexane solution) is added under a nitrogen atmosphere. After about 2 to 3 minutes, a nickel catalyst (87mg of 100μmol catalyst, about 50mL of dichloromethane) is added, and then the pressure is increased for polymerization. Under rapid stirring (more than 1000 revolutions), ethylene is introduced and maintained at a corresponding pressure (1 to 28 bar). After the corresponding polymerization time (60 minutes), the pressure reactor is emptied, the polymerization reaction is quenched, the polymer is filtered, and it is dried in a vacuum oven to constant weight.

[0201] The change of polymerization reactor pressure over time is shown in Figure 8(a) At 0 min, the catalyst was added and the material was added in the ethylene atmosphere by opening the kettle under positive pressure, so the pressure dropped. After the catalyst was added, polymerization began. At the same time, high-pressure ethylene gas was introduced to increase the pressure of polymerization, so the pressure rose.

[0202] The overall ethylene consumption changes over time. Figure 8 (b), the catalyst was added at 0min, and the feed was added by opening the reactor under positive pressure, so a small amount of ethylene gas was consumed. At the end of the reaction, a total of about 2000L of ethylene gas was consumed. The temperature control data of the polymerization reactor during this period changed with time. Figure 8 (c), in order to prevent excessive heat release due to polymerization, the catalyst was added at about 25°C, and then the pressure was increased to start polymerization. The polymerization temperature increased due to the heat release of polymerization. During the polymerization, the system temperature was maintained at about 25°C. The final polymerization product was about 1 kg ( Fig. 9 ).

[0203] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention can be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the present invention.

Claims

1. A method for preparing an α-diimine ligand, characterized in that: include, The diimine ligand (a) is dissolved in an organic solvent, a lithium reagent is added dropwise, and the mixture is stirred at 20-50° C. overnight to obtain a reaction system; Dissolve the halide (b) in an organic solvent, add dropwise to the reaction system, and reflux and stir at 35-70°C for 24h; After the reaction is completed, the mixture is cooled to room temperature, water is added to quench the reaction, the organic layer is washed with water, and the solvent is evaporated in vacuo until a solid appears. The crude product is washed with an excess of cold hexane, the solid is separated by filtration and dried under vacuum to obtain a skeleton-modified α-diimine ligand (c); The structural formula of the diimine ligand (a) is: The structural formula of the halogenated compound (b) is: The structural formula of α-diimine ligand (c) is: Among them, R 1 , R 2 , R 4 , R 5 H, CH3, CH(CH3)2, One of R 8 H, CH3, t Bu tert-butyl, F, OCH3, CF3, NO2, R 8 Located at one or more of the three positions of ortho, meta and para of the benzene ring; R 3 , R 6 H, CH3, C1-C20 alkyl, t Bu one of tert-butyl, F, Cl, C1-C20 alkoxy, CF3, NO2, N(CH3)2; n = 0 or 1; R 7 is CH3, C1-C20 alkyl, C1-C20 alkoxy, One of; X is Cl, Br or I.

2. The preparation method according to claim 1, characterized in that: The organic solvent is one of pentane, hexane, tetrahydrofuran and toluene.

3. The preparation method according to claim 1 or 2, characterized in that: The lithium reagent is a mixed solution of n-butyl lithium and tetramethylethylenediamine in a volume ratio of 1:1, lithium diethylamide, methyl lithium, and tert-butyl lithium.

4. The preparation method according to claim 1, characterized in that: The molar ratio of the diimine ligand (a) to the lithium reagent is 1:2-5.

5. The α-diimine ligand obtained by the preparation method according to any one of claims 1 to 4.

6. A method for preparing an α-diimine nickel catalyst using the α-diimine ligand described in claim 5, characterized in that: include, The α-diimine ligand and the organometallic compound ethylene glycol dimethyl ether nickel bromide are mixed and dissolved in dichloromethane or chloroform at an equivalent ratio of 1:1 to 1:5, stirred at 20 to 50° C. for 12 to 60 hours, the solvent is evaporated in vacuo, and the mixed solution is recrystallized; The solid is separated by filtration, washed with hexane or diethyl ether, and dried under vacuum to obtain the α-diimine nickel catalyst; The mixed liquid is one of the following mixed liquids: a mixed liquid with a volume ratio of 1:1 between n-hexane and dichloromethane, a mixed liquid with a volume ratio of 1:1 between n-hexane and chloroform, a mixed liquid with a volume ratio of 1:1 between ether and dichloromethane, and a mixed liquid with a volume ratio of 1:1 between ether and chloroform.

7. The α-diimine nickel catalyst prepared by the preparation method according to claim 6, characterized in that: The structural formula of the α-diimine nickel catalyst is: Among them, R 1 , R 2 , R 4 , R 5 H, CH3, CH(CH3)2, One of R 8 H, CH3, t Bu tert-butyl, F, OCH3, CF3, NO2, R 8 Located at one or more of the three positions of ortho, meta and para of the benzene ring; R 3 , R 6 H, CH3, C1-C20 alkyl, t Bu one of tert-butyl, F, Cl, C1-C20 alkoxy, CF3, NO2, N(CH3)2; n = 0 or 1; R 7 is CH3, C1-C20 alkyl, C1-C20 alkoxy, One of them.

8. A method for preparing an α-diimine nickel catalyst using the α-diimine ligand described in claim 5, characterized in that: include, α-diimine ligand, Ni(acac)2 (acac = acetylacetone), [Ph3C][B(C6F5)4] or sodium tetrakis[3,5-bis(trifluoromethyl)phenyl]borate are dissolved in dichloromethane or chloroform in a ratio of 1:1:1, stirred at 20-50°C for 12-60 hours, and the solvent is evaporated in vacuo; The solid was washed with n-hexane and ether, separated by filtration, washed with hexane and ether three times respectively and dried under vacuum to obtain an α-diimine nickel catalyst.

9. The α-diimine nickel catalyst prepared by the preparation method of claim 8, characterized in that: The structural formula of the α-diimine nickel catalyst is: Among them, R 1 , R 2 , R 4 , R 5 H, CH3, CH(CH3)2, One of R 8 H, CH3, t Bu tert-butyl, F, OCH3, CF3, NO2, R 8 Located at one or more of the three positions of ortho, meta and para of the benzene ring; R 3 , R 6 H, CH3, C1-C20 alkyl, t Bu one of tert-butyl, F, Cl, C1-C20 alkoxy, CF3, NO2, N(CH3)2; n = 0 or 1; R 7 is CH3, C1-C20 alkyl, C1-C20 alkoxy, One of them.

10. Use of the α-diimine nickel catalyst according to claim 7 or 9 in olefin polymerization.

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