Preparation method of polyethylene oil

Abstract

The invention provides a preparation method of polyethylene oil, which comprises the following steps: fully contacting ethylene with a nickel metal combined catalyst and carrying out polymerization reaction to obtain the polyethylene oil, wherein the nickel metal combined catalyst comprises a main catalyst and a co-catalyst in a molar ratio of 1: (100-1000), the co-catalyst is aluminum alkyl, and the main catalyst is a bidentate nitrogen-doped nickel complex. According to the present invention, the substituent group of the amido of the adopted bidentate aza-matched nickel complex in the nickel metal combination catalyst is the flexible alkyl group with small steric hindrance, and the substituent group of the imine is the rigid aryl group with large steric hindrance, such that the highly branched low molecular weight polyethylene oil can be prepared with the catalyst under the high pressure at the high activity so as to improve the polyethylene oil yield.

Description

Technical Field

[0001] This invention relates to the field of olefin catalytic polymerization technology, and specifically to a method for preparing polyethylene oil. Background Technology

[0002] Compared to high molecular weight polyethylene, research reports on the application of low molecular weight polyethylene products are relatively few, especially on highly branched low molecular weight polyethylene oils. These highly branched low molecular weight polyethylene oils possess a unique highly branched structure, giving them excellent viscosity-temperature properties and low-temperature flow properties, thus enabling their application as lubricants, viscosity index modifiers, and processing viscosity modifiers. For example, poly-α-olefin (PAO) is a type of highly branched liquid polyolefin product containing abundant long branches (generally C8). Due to its unique highly branched structure, PAO exhibits excellent viscosity-temperature properties and low-temperature flow properties; furthermore, PAO's chemical composition does not contain easily oxidized impurities such as aromatics, nitrogen, and sulfur, thus possessing excellent antioxidant stability.

[0003] CN114369185A discloses a homopolymer highly branched polyethylene and its preparation method. The homopolymer highly branched polyethylene has a branching degree >60 branches / 1000°C, with methyl content accounting for 60-75%, C2-C5 branches accounting for 15-35%, and C6 and above branches accounting for 5-10%. The preparation of this homopolymer highly branched polyethylene uses a single-active-center nickel metal composite catalyst as the main catalyst and diethylaluminum chloride as the co-catalyst to catalyze the homopolymerization of ethylene to prepare highly branched polyethylene. The polymerization temperature is 60-80°C, and the polymerization pressure is 500-2000 kPa. The prepared highly branched polyethylene melt is suitable for producing polyethylene materials requiring high toughness and easy heat sealing; however, its shape is not oily, and the branching degree of the product is not high, which cannot meet the application requirements of oily polyethylene in the lubricating oil field. Summary of the Invention

[0004] To solve the above-mentioned technical problems, the purpose of this invention is to provide a method for preparing polyethylene oil to obtain highly branched low molecular weight polyethylene oil.

[0005] To achieve the above objectives, the present invention provides a method for preparing polyethylene oil, comprising: fully contacting ethylene with a nickel metal composite catalyst and allowing a polymerization reaction to occur, thereby obtaining polyethylene oil; wherein the nickel metal composite catalyst comprises a main catalyst and a co-catalyst in a molar ratio of 1:100-1000, the co-catalyst being an alkylaluminum, and the main catalyst being a bidentate azahexane nickel complex having the structure shown in formula (I):

[0006]

[0007] R1 and R2 may be the same or different, and each is independently selected from substituted or unsubstituted C1-C. 10 Alkyl, C1-C 10 Alkoxy, C2-C 10 alkenyl or C6-C 10 Aryl;

[0008] R3 is selected from hydrogen, methyl, methoxy, and trifluoromethyl;

[0009] X is selected from chlorine or bromine.

[0010] This invention utilizes a novel catalyst composition to increase the yield of highly branched polyethylene oil, stabilize and improve the degree of branching of the product, thereby solving the problems of low yield and large variation in branching structure of existing highly branched polyethylene oil.

[0011] The nickel metal composite catalyst used in this invention employs a bidentate nitrogen-heterotropic nickel complex containing two different nitrogen coordinating atoms: an amino nitrogen (sp3 hybridization) and an imine nitrogen (sp2 hybridization). Due to the different hybridization modes of the nitrogen atoms, the two different nitrogen coordinating atoms have different bonding strengths with the nickel metal center. The amino nitrogen has a stronger bonding ability with the nickel metal, thus improving the thermal stability of the catalyst. Simultaneously, the strong bonding between the amino nitrogen and the nickel metal also enhances the chain-walking ability of the catalyst. Furthermore, the substituent (R1) of the amino group is a sterically hindered and flexible alkyl group, while the substituent of the imine group is a sterically hindered and rigid aryl group. Through this "combination of rigidity and flexibility" and "combination of large and small" substituent steric hindrance strategies, chain transfer can occur during the catalytic polymerization of olefins, thereby efficiently preparing low molecular weight polymers.

[0012] Furthermore, the chain-walking ability of the nickel metal composite catalyst used in this invention is not sensitive to ethylene pressure, thus the branched structure of the polyethylene product obtained is relatively uniform and stable.

[0013] According to a specific embodiment of the present invention, preferably, in the bidentate azirmonopolymer nickel complex, R1 and R2 are each independently selected from methyl, ethyl, propenyl or phenyl, more preferably methyl or ethyl.

[0014] According to a specific embodiment of the present invention, preferably, in the bidentate azirmonotriazine nickel complex, R3 is selected from methoxy or methyl.

[0015] According to a specific embodiment of the present invention, preferably, the bidentate azahexane nickel complex satisfies any one of the following conditions:

[0016] R1 and R2 are both methyl groups, R3 is hydrogen, and X is chlorine.

[0017] R1 and R2 are both methyl groups, R3 is methyl, and X is chlorine.

[0018] R1 and R2 are both methyl groups, R3 is methoxy group, and X is chlorine.

[0019] R1 and R2 are both methyl groups, R3 is trifluoromethyl, and X is chlorine.

[0020] R1 and R2 are both ethyl groups, R3 is hydrogen, and X is chlorine.

[0021] R1 and R2 are both ethyl groups, R3 is methyl, and X is chlorine.

[0022] R1 and R2 are both ethyl groups, R3 is methoxy, and X is chlorine.

[0023] R1 and R2 are both ethyl groups, R3 is trifluoromethyl, and X is chlorine.

[0024] R1 and R2 are both methyl groups, R3 is hydrogen, and X is bromine;

[0025] R1 and R2 are both methyl groups, R3 is methyl group, and X is bromine.

[0026] R1 and R2 are both methyl groups, R3 is methoxy group, and X is bromine.

[0027] R1 and R2 are both methyl groups, R3 is trifluoromethyl, and X is bromine;

[0028] R1 and R2 are both ethyl groups, R3 is hydrogen, and X is bromine;

[0029] R1 and R2 are both ethyl groups, R3 is a methyl group, and X is a bromine group;

[0030] R1 and R2 are both ethyl groups, R3 is methoxy, and X is bromine.

[0031] R1 and R2 are both ethyl groups, R3 is trifluoromethyl, and X is bromine.

[0032] According to a specific embodiment of the present invention, preferably, the alkyl aluminum includes methylaluminoxane (MAO), modified methylaluminoxane (MMAO), diethylaluminum chloride (AlEt2Cl), diethylaluminum chloride (AlEtCl2), and more preferably methylaluminoxane and / or modified methylaluminoxane.

[0033] According to a specific embodiment of the present invention, preferably, the molar ratio of alkylaluminum to the bidentate azirconium nickel complex is 300-600:1. In the present invention, the molar ratio of the bidentate azirconium nickel complex to the alkylaluminum is equivalent to the Al / Ni molar ratio in the nickel metal composite catalyst.

[0034] The bidentate azahexane nickel complex of the present invention is prepared by the following method:

[0035] α-Bromoisobutyraldehyde and a dialkylamine of the general formula R1R2-NH are subjected to a substitution reaction to obtain amino-substituted isobutyraldehyde as shown in formula (II).

[0036] The amino-substituted isobutyraldehyde shown in formula (II) undergoes a condensation reaction with the arylnaphthylamine shown in formula (III) to obtain the azaligand shown in formula (IV);

[0037] The aza-ligand is subjected to a coordination reaction with NiX2 to obtain the bidentate aza-nickel complex.

[0038]

[0039] The molar ratio of amino-substituted isobutyraldehyde to arylnaphthylamine is 1:1.2-2, more preferably 1:1.5; the molar ratio of azaligand to NiX2 is 1-1.5:1, more preferably 1.2:1; the condensation reaction temperature is 80-150℃, and the reaction time is 6-48h.

[0040] The synthetic route for the bidentate azahexane nickel complex of the present invention is as follows:

[0041]

[0042] According to a specific embodiment of the present invention, preferably, the pressure of ethylene during the polymerization reaction is 1-20 atm, more preferably 5-15 atm.

[0043] According to a specific embodiment of the present invention, preferably, the temperature of the polymerization reaction is 20-150°C, more preferably 30-80°C, and the time (residence time) of the polymerization reaction is 0.5-8h.

[0044] According to a specific embodiment of the present invention, preferably, during the polymerization reaction, the nickel metal composite catalyst is dispersed in a solvent, wherein the solvent includes one or more of alkanes, aromatics, halogenated hydrocarbons, and olefins.

[0045] According to a specific embodiment of the present invention, preferably, the solvent includes one or more combinations of n-hexane, methylcyclohexane, cyclohexane, heptane, decane, benzene, toluene, xylene, cumene, 1-butene, 1-hexene or 1-octene, more preferably n-hexane and / or toluene.

[0046] The method for preparing polyethylene oil of the present invention involves a highly active ethylene polymerization reaction under a catalyst system with a bidentate azide nickel complex, by controlling the reaction pressure, temperature, catalyst ratio and polymerization time, to generate a crude product of highly branched polyethylene oil.

[0047] According to a specific embodiment of the present invention, preferably, the method for preparing polyethylene oil further includes: terminating the polymerization reaction with hydrochloric acid to obtain polyethylene oil.

[0048] According to a specific embodiment of the present invention, preferably, the method for preparing polyethylene oil further includes purifying the terminated reaction solution; the purification step includes: washing the reaction solution with water, separating and drying it, then performing column chromatography, and finally removing the solvent to obtain polyethylene oil.

[0049] The technical solution provided by this invention has the following beneficial effects:

[0050] The nickel metal composite catalyst used in this invention has a bidentate aziridine nickel complex with a small steric hindrance and flexible alkyl group as the substituent for the amine group and a large steric hindrance and rigid aryl group as the substituent for the imine group. Through this "combination of rigidity and flexibility" and "combination of large and small" substituent steric hindrance strategy, the catalyst can be guaranteed to produce highly branched low molecular weight polyethylene oil with high activity under high pressure, thereby improving the polyethylene oil yield.

[0051] The catalyst used in this invention has a chain-walking ability that is not sensitive to ethylene pressure. Increasing ethylene pressure has little effect on the branching of the product, but it can achieve the beneficial effect of significantly improving catalytic activity. Attached Figure Description

[0052] Figure 1 The image shows the 1H NMR spectrum of the bidentate azahexane nickel complex of Example 20. Detailed Implementation

[0053] In order to provide a clearer understanding of the technical features, objectives and beneficial effects of the present invention, the technical solution of the present invention will now be described in detail below, but it should not be construed as limiting the scope of implementation of the present invention.

[0054] This invention utilizes 16 bidentate aziridine nickel complexes with specific chemical structures (as shown in Formula I). ​​These 16 bidentate aziridine nickel complexes are named Ni1-Ni16, and the types of each group are as follows:

[0055] In the bidentate azametal nickel complex Ni1, R1 and R2 are both methyl groups, R3 is hydrogen, and X is chlorine.

[0056] The bidentate azahexane nickel complex Ni2 has R1 and R2 both being methyl, R3 being methyl, and X being chlorine;

[0057] The bidentate azametallic nickel complex Ni3 has R1 and R2 both being methyl groups, R3 being a methoxy group, and X being a chlorine group.

[0058] The bidentate azahexane nickel complex Ni4 has R1 and R2 both being methyl groups, R3 being trifluoromethyl, and X being chlorine.

[0059] The bidentate azirmonopolymer Ni5 has two ethyl groups (R1 and R2), one hydrogen group (R3), and one chlorine group (X).

[0060] The bidentate azahexane nickel complex Ni6 has R1 and R2 both being ethyl groups, R3 being a methyl group, and X being a chlorine group;

[0061] The bidentate azirmonopolymer Ni7 has two ethyl groups (R1 and R2), one methoxy group (R3), and one chlorine group (X).

[0062] The bidentate azahexane nickel complex Ni8 has R1 and R2 both being ethyl groups, R3 being trifluoromethyl, and X being chlorine.

[0063] The bidentate azametal nickel complex Ni9 has R1 and R2 both methyl, R3 hydrogen, and X bromine;

[0064] The bidentate azahexane nickel complex Ni10 has R1 and R2 both being methyl, R3 being methyl, and X being bromine;

[0065] The bidentate azapyridine nickel complex Ni11 has R1 and R2 both being methyl, R3 being methoxy, and X being bromine;

[0066] The bidentate azahexane nickel complex Ni12 has R1 and R2 both being methyl, R3 being trifluoromethyl, and X being bromine;

[0067] The bidentate azirmonopolymer Ni13 has two ethyl groups (R1 and R2), one hydrogen group (R3), and one bromine group (X).

[0068] The bidentate azahexane nickel complex Ni14 has R1 and R2 both being ethyl groups, R3 being a methyl group, and X being a bromine group.

[0069] The bidentate azirmonopolymer nickel complex Ni15 has R1 and R2 both being ethyl groups, R3 being a methoxy group, and X being a bromine group.

[0070] The bidentate azahexane nickel complex Ni16 has R1 and R2 as ethyl groups, R3 as trifluoromethyl groups, and X as bromine.

[0071] The aforementioned bidentate aziridine nickel complexes were synthesized from eight aziridines with specific chemical structures (as shown in Formula III) and NiCl2 or NiBr2. The eight aziridines were named L1-L8, and the types of each group are as follows:

[0072] Azaligands L1, R1, and R2 are all methyl groups, and R3 is hydrogen;

[0073] Azaligand L2, R1 and R2 are both methyl groups, and R3 is a methyl group;

[0074] The azaligand L3 has two methyl groups, R1 and R2, and R3 is methoxy.

[0075] The azaligand L4, R1 and R2 are both methyl groups, and R3 is a trifluoromethyl group;

[0076] The azaligand L5 has ethyl groups R1 and R2, and hydrogen R3.

[0077] In the azaligand L6, R1 and R2 are both ethyl groups, and R3 is a methyl group;

[0078] The azaligand L7 has ethyl groups R1 and R2, and methoxy groups R3.

[0079] The azaligand L8 has two ethyl groups, R1 and R2, and R3 is a trifluoromethyl group.

[0080] The above-mentioned azaligands were synthesized from two specific structures of amino-substituted isobutyraldehyde (as shown in Formula II) and four specific structures of arylnaphthylamines (as shown in general Formula III). The two amino-substituted isobutyraldehydes were named B1 and B2, respectively, and the four arylnaphthylamines were named A1-A4, respectively. The types of each group are as follows:

[0081] Amino-substituted isobutyraldehyde B1, where R1 and R2 are both methyl groups;

[0082] Amino-substituted isobutyraldehyde B2, where R1 and R2 are both ethyl groups;

[0083] Arylnaphthylamine A1, R3 is hydrogen;

[0084] Arylnaphthylamine A2, R3 is methyl;

[0085] Arylnaphthylamine A3, where R3 is a methoxy group;

[0086] Arylnaphthylamine A4, R3 is trifluoromethyl.

[0087] The above-mentioned arylnaphthylamines A1-A4 can be prepared according to the method reported in the literature (Synthesis of Highly BranCHed Polyethylene Using “SandwiCH” (8-p-Tolyl naphthylα-diimine)nickel(II) Catalysts[J]. Organometallics 2013, 32(18), 5136-5143).

[0088] Example 1

[0089] This embodiment provides an amino-substituted isobutyraldehyde B1, the synthesis method of which is as follows:

[0090] At 0°C, bromoisobutyraldehyde (4 g, 26 mmol) was placed in 30 mL of diethyl ether, and Me2NH (33 mL, 2 min THF, 65 mmol) was added dropwise at 0°C. The mixture was stirred for 4 h, and the ammonium salt was removed by filtration. The solvent was removed by rotary evaporation to obtain 2.60 g of yellow viscous liquid, with a yield of 86%.

[0091] 1H NMR (CDCl3, 400MHz) δ (ppm): 9.40 (s, 1H, CHO), 2.43 (s, 6H, N (CH3) 2), 1.05 (s, 6H, C (CH3) 2).

[0092] Example 2

[0093] This embodiment provides an amino-substituted isobutyraldehyde B2, the synthesis method of which differs from Example 1 only in that Et2NH is used instead of Me2NH; the rest is the same as in Example 1. The final product yielded 3.34 g, with a yield of 88%.

[0094] 1H NMR (CDCl3, 400MHz) δ (ppm): 9.39 (s, 1H, CHO), 2.50 (q, 4H, NCH2CH3), 1.07 (s, 6H, C (CH3) 2), 1.02 (t, 6H, NCH2CH3).

[0095] Example 3

[0096] This embodiment provides an aza-ligand L1, the synthesis method of which is as follows:

[0097] The amino-substituted isobutyraldehyde B1 (1 g, 8.7 mmol) and 8-phenyl-1-naphthylamine (A1) (2.87 g, 13.1 mmol) from Example 1 were placed in a 100 mL round-bottom flask with a side arm, 30 mL of toluene and 0.2 mL of formic acid were added, and the mixture was refluxed at 110 °C for 24 h. The mixture was then subjected to column chromatography with petroleum ether / ethyl acetate to obtain 2.1 g of off-white solid, which was the azaligand L1, with a yield of 75%.

[0098] 1H NMR (CDCl3, 400MHz) δ (ppm): 7.83 (dd, 1H, Ar-H), 7.72 (dd, 1H, Ar-H), 7.47 (s, 1H, CH=N), 7.45-7.39 (m ,2H,Ar-H),7.24-7.10(m,6H,Ar-H),6.68(dd,1H,Ar-H),2.17(s,6H,N(CH3)2),0.74(s,6H,C(CH3)2).

[0099] 13C NMR (CDCl3, 100MHz) δ (ppm): 168.85 (CH=N), 150.37, 142.10, 139.57, 135.52, 135.14, 130.20, 129.63, 129.12, 128.72, 128.02,128.53,127.85,126.27,126.05,125.73,60.69(C(CH3)2),39.16(N(CH3)2),21.11(Ar-CH3),18.48(C(CH3)2).

[0100] Example 4

[0101] This embodiment provides an azaligand L2, the synthesis method of which differs from that of Example 3 only in that 8-p-tolyl-1-naphthylamine (A2) is used instead of 8-phenyl-1-naphthylamine (A1), and the other conditions are the same as in Example 3; the azaligand L2 is finally obtained with a yield of 84%.

[0102] 1H NMR (CDCl3, 400MHz) δ (ppm): 7.83 (dd, 1H, Ar-H), 7.72 (dd, 1H, Ar-H), 7.47 (s, 1H, CH=N), 7.45-7.39 (m, 2H, Ar-H) ,7.24-7.12(m,5H,Ar-H),6.69(dd,1H,Ar-H),2.40(s,3H,Ar-CH3),2.17(s,6H,N(CH3)2),0.75(s,6H,C(CH3)2).

[0103] 13C NMR (CDCl3, 100MHz) δ (ppm): 168.84 (CH=N), 150.37, 142.10, 139.57, 135.52, 135.14, 130.20, 129.63, 129.12, 128.72, 128.02, 128.53,127.85,126.27,126.05,125.73,125.12,(Ar-C),60.69(C(CH3)2),39.16(N(CH3)2),21.11(Ar-CH3),18.48(C(CH3)2).

[0104] Example 5

[0105] This embodiment provides an azaligand L3, the only difference between which is the synthesis method and that of Example 3, except that 8-p-anisole-1-naphthylamine (A3) is used instead of 8-phenyl-1-naphthylamine (A1), and the other conditions are the same as in Example 3; the azaligand L3 is finally obtained with a yield of 80%.

[0106] 1H NMR (CDCl3, 400MHz) δ (ppm): 7.83 (dd, 1H, Ar-H), 7.72 (dd, 1H, Ar-H), 7.45 (s, 1H, CH=N), 7.45-7.39 (m, 2H, Ar-H), 7.24-7.12(m,5H,Ar-H),6.67(dd,1H,Ar-H),3.40(s,3H,Ar-OCH3),2.16(s,6H,N(CH3)2),0.72(s,6H,C(CH3)2).

[0107] 13C NMR (CDCl3, 100MHz) δ (ppm): 168.84 (CH=N), 150.37, 142.10, 139.57, 135.52, 135.14, 130.20, 129.63, 129.12, 128.72, 1 28.02,128.53,127.85,126.27,126.05,125.73,60.69(C(CH3)2),53.62(1C,O-CH3),39.16(N(CH3)2),18.48(C(CH3)2).

[0108] Example 6

[0109] This embodiment provides an azaligand L4, the only difference between which is the synthesis method and that of Example 3, except that 8-p-trifluorotolyl-1-naphthylamine (A4) is used instead of 8-phenyl-1-naphthylamine (A1), and the other conditions are the same as in Example 3; the azaligand L4 is finally obtained with a yield of 84%.

[0110] 1H NMR (CDCl3, 400MHz) δ (ppm): 7.85 (dd, 1H, Ar-H), 7.73 (dd, 1H, Ar-H), 7.47 (s, 1H, CH=N), 7 .45-7.32(m,7H,Ar-H),6.69(dd,1H,Ar-H),2.20(s,6H,N(CH3)2),0.76(s,6H,C(CH3)2).

[0111] 13C NMR (CDCl3, 100MHz) δ (ppm): 168.84 (CH=N), 150.37, 142.10, 139.57, 135.52, 135.14, 130.20, 129.63, 129.12, 128.72,128.02,128.53,127.85,126.27,126.05,125.73,61.69(C(CH3)2),39.16(N(CH3)2),18.48(C(CH3)2).

[0112] 19F NMR (CDCl3, 400MHz) δ (ppm): -60.60 (s, 3F, CF3).

[0113] Example 7

[0114] This embodiment provides an azaligand L5, the synthesis method of which differs from that of Example 3 only in that isobutyraldehyde B2 is replaced by an amino group instead of isobutyraldehyde B1, and the other conditions are the same as in Example 3; the azaligand L5 is finally obtained with a yield of 78%.

[0115] 1H NMR (CDCl3, 400MHz) δ (ppm): 7.81 (dd, 1H, Ar-H), 7.72 (dd, 1H, Ar-H), 7.47 (s, 1H, CH=N), 7.45-7.39 (m, 2H, Ar-H), 7.2 4-7.10(m,6H,Ar-H),6.68(dd,1H,Ar-H),2.12(q,4H,N(CH2CH3)2),0.75(s,6H,C(CH3)2),0.68(s,6H,N(CH2CH3)2).

[0116] 13C NMR (CDCl3, 100MHz) δ (ppm): 168.84 (CH=N), 150.37, 142.10, 139.57, 135.52, 135.14, 130.20, 129.63, 129.12, 128.72, 128.02 ,128.53,127.85,126.27,126.05,125.73,125.12,(Ar-C),63.0(C(CH3)2),43.8(NCH2CH3),21.8(C(CH3)2),15.8(NCH2CH3).

[0117] Example 8

[0118] This embodiment provides an azaligand L6, the synthesis method of which differs from that of Example 4 only in that isobutyraldehyde B2 is replaced by an amino group instead of isobutyraldehyde B1, and the other conditions are the same as in Example 4; the azaligand L6 is finally obtained with a yield of 82%.

[0119] 1H NMR (CDCl3, 400MHz) δ (ppm): 7.83 (dd, 1H, Ar-H), 7.72 (dd, 1H, Ar-H), 7.47 (s, 1H, CH=N), 7.45-7.39 (m, 2H, Ar-H), 7.24-7.12 (m, 5H,Ar-H),6.69(dd,1H,Ar-H),2.40(s,3H,Ar-CH3),2.11(q,4H,N(CH2CH3)2),0.72(s,6H,C(CH3)2),0.67(s,6H,N(CH2CH3)2).

[0120] 13C NMR (CDCl3, 100MHz) δ (ppm): 168.84 (CH=N), 150.37, 142.10, 139.57, 135.52, 135.14, 130.20, 129.63, 129.12, 128.72, 128.02, 128.53 ,127.85,126.27,126.05,125.73,125.12,(Ar-C),63.0(C(CH3)2),43.8(NCH2CH3),21.8(C(CH3)2),21.11(Ar-CH3),15.8(NCH2CH3).

[0121] Example 9

[0122] This embodiment provides an azaligand L7, the synthesis method of which differs from that of Example 5 only in that isobutyraldehyde B2 is replaced by an amino group instead of isobutyraldehyde B1, and the other conditions are the same as in Example 5; the azaligand L7 is finally obtained with a yield of 78%.

[0123] 1H NMR (CDCl3, 400MHz) δ (ppm): 7.83 (dd, 1H, Ar-H), 7.72 (dd, 1H, Ar-H), 7.45 (s, 1H, CH=N), 7.45-7.39 (m, 2H, Ar-H), 7.24-7.12 (m, 5H,Ar-H),6.67(dd,1H,Ar-H),3.40(s,3H,Ar-OCH3),2.09(q,4H,N(CH2CH3)2),0.72(s,6H,C(CH3)2),0.66(s,6H,N(CH2CH3)2).

[0124] 13C NMR (CDCl3, 100MHz) δ (ppm): 168.84 (CH=N), 150.37, 142.10, 139.57, 135.52, 135.14, 130.20, 129.63, 129.12, 128.72, 128.02, 128.53 ,127.85,126.27,126.05,125.73,125.12,(Ar-C),63.0(C(CH3)2),53.52(C,O-CH3),43.8(NCH2CH3),21.8(C(CH3)2),15.8(NCH2CH3).

[0125] Example 10

[0126] This embodiment provides an azaligand L8, the synthesis method of which differs from that of Example 6 only in that isobutyraldehyde B2 is replaced by an amino group instead of isobutyraldehyde B1, and the other conditions are the same as in Example 6; the azaligand L8 is finally obtained with a yield of 76%.

[0127] 1H NMR (CDCl3, 400MHz) δ (ppm): 7.85 (dd, 1H, Ar-H), 7.73 (dd, 1H, Ar-H), 7.47 (s, 1H, CH=N), 7.45-7.32 (m, 7 H,Ar-H),6.69(dd,1H,Ar-H),2.16(q,4H,N(CH2CH3)2),0.76(s,6H,C(CH3)2),0.70(s,6H,N(CH2CH3)2).

[0128] 13C NMR (CDCl3, 100MHz) δ (ppm): 169.63 (CH=N), 150.37, 142.10, 139.57, 135.52, 135.14, 130.20, 129.63, 129.12, 128.92, 128.02, 128.53 ,127.85,126.27,126.05,125.81,125.42,(Ar-C),63.0(C(CH3)2),53.52(C,O-CH3),43.9(NCH2CH3),21.9(C(CH3)2),15.7(NCH2CH3).

[0129] 19F NMR (CDCl3, 400MHz) δ (ppm): -60.70 (s, 3F, CF3).

[0130] Example 11

[0131] This embodiment provides a bidentate azahexane nickel complex Ni1, the synthesis method of which is as follows:

[0132] Under anhydrous and oxygen-free conditions, azaligand L1 (800 mg, 0.91 mmol) and (DME)NiCl2 (0.17 g, 0.75 mmol) were added to a Schlenk tube and reacted overnight in dichloromethane. The insoluble matter was removed by filtration, and the filtrate was evaporated under reduced pressure to about 5 mL of solvent remaining. Hexane was added to precipitate the precipitate, which was collected by filtration and washed three times with hexane. The solvent was then dried to obtain 0.45 g of purple powder, which is the bidentate azaligand nickel complex Ni1, with a yield of 80%.

[0133] MS(FAB,m / z):447.1(M++1).Anal.Calcd for C22H24Cl2N2Ni:C,59.24;H,5.42;Found:C,59.21;H,5.28.

[0134] ¹H NMR (CDCl₃, 400MHz) δ (ppm): 22.44 (s, Ar-H), 11.70 (br, Ar-H), 11.49 (br, Ar-H), 10.99 (dd, Ar-H), 8.05 (s, CH=N), 7.85 (m, Ar-H), 7.18–7.15 (m, Ar-H), 6.83 (d, Ar-H), 2.58 (s, N(CH₃)₂), 1.22 (s, C(CH₃)₂), -0.59 (s, N(CH₃)₂), -1.22 (s, C(CH₃)₂). Based on the integral ratio of N-CH₃, the ratio of the two isomers is 1.8:1.

[0135] Example 12

[0136] This embodiment provides a bidentate aziridine nickel complex Ni2, the only difference between which is the synthesis method and that of Example 11, except that aziridine L2 is used instead of aziridine L1, and the other conditions are the same as in Example 11; finally, a bidentate aziridine nickel complex Ni1 is obtained with a yield of 82%.

[0137] MS(FAB,m / z):461.2(M++1).Anal.Calcd for C23H26Cl2N2Ni:C,60.05;H,5.70;Found:C,60.03;H,5.72.

[0138] ¹H NMR (CDCl₃, 400MHz) δ (ppm): 22.46 (s, Ar-H), 11.70 (br, Ar-H), 11.49 (br, Ar-H), 10.99 (dd, Ar-H), 8.07 (s, CH=N), 7.85 (m, Ar-H), 7.18–7.15 (m, Ar-H), 6.83 (d, Ar-H), 3.26 (s, Ar-CH₃), 2.58 (s, N(CH₃)₂), 2.40 (s, Ar-CH₃), 1.22 (s, C(CH₃)₂), -0.54 (s, N(CH₃)₂), -1.23 (s, C(CH₃)₂). Based on the integral ratio of N-CH₃, the ratio of the two isomers is 2:1.

[0139] Example 13

[0140] This embodiment provides a bidentate aziridine nickel complex Ni3, the only difference between which is the synthesis method and that of Example 11, except that aziridine L3 is used instead of aziridine L1, and the other conditions are the same as in Example 11; finally, a bidentate aziridine nickel complex Ni3 is obtained with a yield of 80%.

[0141] MS(FAB,m / z):477.1(M++1).Anal.Calcd for C23H26Cl2N2NiO:C,58.03;H,5.51;Found:C,58.00;H,5.52.

[0142] ¹H NMR (CDCl₃, 400MHz) δ (ppm): 22.44 (s, Ar-H), 11.70 (br, Ar-H), 11.49 (br, Ar-H), 10.99 (dd, Ar-H), 8.07 (s, CH=N), 7.85 (m, Ar-H), 7.18–7.15 (m, Ar-H), 6.83 (d, Ar-H), 3.76 (s, -OCH₃), 3.40 (s, -OCH₃), 2.53 (s, N(CH₃)₂), 1.21 (s, C(CH₃)₂), -0.51 (s, N(CH₃)₂), -1.20 (s, C(CH₃)₂). Based on the integral ratio of N-CH₃, the ratio of the two isomers is 2.2:1.

[0143] Example 14

[0144] This embodiment provides a bidentate aziridine nickel complex Ni4, the only difference between which is the synthesis method and that of Example 11, except that aziridine L4 is used instead of aziridine L1, and the other conditions are the same as in Example 11;

[0145] The final product was a bidentate azide nickel complex Ni4, with a yield of 81%.

[0146] MS(FAB,m / z):515.1(M++1).Anal.Calcd for C23H23Cl2F3N2Ni:C,53.74;H,4.51;Found:C,53.75;H,4.50.

[0147] ¹H NMR (CDCl₃, 400MHz) δ (ppm): 22.49 (s, Ar-H), 11.90 (br, Ar-H), 11.79 (br, Ar-H), 10.99 (dd, Ar-H), 8.15 (s, CH=N), 7.85 (m, Ar-H), 7.18–7.15 (m, Ar-H), 6.83 (d, Ar-H), 3.26 (s, Ar-CH₃), 2.58 (s, N(CH₃)₂), 2.40 (s, Ar-CH₃), 1.20 (s, C(CH₃)₂), -0.52 (s, N(CH₃)₂), -1.18 (s, C(CH₃)₂). Based on the integral ratio of N-CH₃, the ratio of the two isomers is 2.3:1.

[0148] Example 15

[0149] This embodiment provides a bidentate aziridine nickel complex Ni5, the only difference between which is the synthesis method and that of Example 11, except that aziridine L5 is used instead of aziridine L1, and the other conditions are the same as in Example 11; the bidentate aziridine nickel complex Ni5 is finally obtained with a yield of 79%.

[0150] MS(FAB,m / z):475.1(M++1).Anal.Calcd for C24H28Cl2N2Ni:C,60.80;H,5.95;Found:C,60.83;H,5.98.

[0151] 1H NMR (CDCl3, 400MHz) δ (ppm): 8.07 (s, 1H, CH=N), 7.78 (dd, 1H, Ar-H), 7.70 (dd, 1H, Ar-H), 7.45-7.33 (m, 2H, Ar-H), 7.2 4-7.10(m,6H,Ar-H),6.68(dd,1H,Ar-H),2.16(q,4H,N(CH2CH3)2),0.71(s,6H,C(CH3)2),0.54(s,6H,N(CH2CH3)2).

[0152] Example 16

[0153] This embodiment provides a bidentate azeotropic nickel complex Ni6, the synthesis method of which differs from that of Example 11 only in that azeotropic ligand L6 is used instead of azeotropic ligand L1, while the other conditions are the same as in Example 11; finally, bidentate azeotropic nickel complex Ni6 is obtained with a yield of 85%. MS(FAB,m / z):489.1(M++1). Anal.Calcd for C25H30Cl2N2Ni:C,61.52;H,6.20;Found:C,61.51;H,6.21.

[0154] 1H NMR (CDCl3, 400MHz) δ (ppm): 8.02 (s, 1H, CH=N), 7.84 (dd, 1H, Ar-H), 7.72 (dd, 1H, Ar-H), 7.40-7.33 (m, 2H, Ar-H), 7.24-7.12 (m, 5H,Ar-H), 6.66(dd,1H,Ar-H), 2.40(s,3H,Ar-CH3), 2.11(q,4H,N(CH2CH3)2), 0.72(s,6H,C(CH3)2), 0.59(s,6H,N(CH2CH3)2).

[0155] Example 17

[0156] This embodiment provides a bidentate aziridine nickel complex Ni7, the only difference between which is the synthesis method and that of Example 11, except that aziridine L7 is used instead of aziridine L1, and the other conditions are the same as in Example 11; finally, the bidentate aziridine nickel complex Ni7 is obtained with a yield of 83%.

[0157] MS (FAB, m / z): 504.1 (M++1). Anal. Calcd for C25H27Cl2N2NiO: C, 59.56; H, 6.00; Found: C, 59.52; H, 5.98.

[0158] 1H NMR (CDCl3, 400MHz) δ (ppm): 8.02 (s, 1H, CH=N), 7.87 (dd, 1H, Ar-H), 7.72 (dd, 1H, Ar-H), 7.41-7.31 (m, 2H, Ar-H), 7.29-7.22 (m, 5H,Ar-H), 6.77(dd,1H,Ar-H), 3.37(s,3H,Ar-OCH3), 2.05(q,4H,N(CH2CH3)2), 0.68(s,6H,C(CH3)2), 0.60(s,6H,N(CH2CH3)2).

[0159] Example 18

[0160] This embodiment provides a bidentate aziridine nickel complex Ni8, the only difference between which is the synthesis method and that of Example 11, except that aziridine L8 is used instead of aziridine L1, and the other conditions are the same as in Example 11; finally, the bidentate aziridine nickel complex Ni8 is obtained with a yield of 83%.

[0161] MS(FAB,m / z):543.1(M++1).Anal.Calcd for C25H27Cl2F3N2Ni:C,55.39;H,5.02;Found:C,55.37;H,5.00.

[0162] 1H NMR (CDCl3, 400MHz) δ (ppm): 8.04 (s, 1H, CH=N), 7.80 (dd, 1H, Ar-H), 7.53 (dd, 1H, Ar-H), 7.35-7.22 (m, 7 H,Ar-H), 6.69(dd,1H,Ar-H), 2.09(q,4H,N(CH2CH3)2), 0.71(s,6H,C(CH3)2), 0.65(s,6H,N(CH2CH3)2).

[0163] Example 19

[0164] This embodiment provides a bidentate nitrided nickel complex Ni9, the only difference between which is the synthesis method and that of Example 11, except that (DME)NiBr2 is used instead of (DME)NiCl2, while the other conditions are the same as in Example 11; (DME)NiBr2 is used instead of (DME)NiCl2; finally, the bidentate nitrided nickel complex Ni9 is obtained with a yield of 81%.

[0165] MS(FAB,m / z):536.0(M++1).Anal.Calcd for C22H24Br2N2Ni:C,55.39;H,5.02;Found:C,49.40;H,4.52.

[0166] ¹H NMR (CDCl₃, 400MHz) δ (ppm): 22.44 (s, Ar-H), 11.70 (br, Ar-H), 11.49 (br, Ar-H), 10.99 (dd, Ar-H), 8.05 (s, CH=N), 7.85 (m, Ar-H), 7.18–7.15 (m, Ar-H), 6.83 (d, Ar-H), 2.58 (s, N(CH₃)₂), 1.20 (s, C(CH₃)₂), -0.56 (s, N(CH₃)₂), -1.24 (s, C(CH₃)₂). Based on the integral ratio of N-CH₃, the ratio of the two isomers is 2.1:1.

[0167] Example 20

[0168] This embodiment provides a bidentate nitrided nickel complex Ni10, the only difference between which is the synthesis method and that of Example 12, except that (DME)NiBr2 is used instead of (DME)NiCl2, and the other conditions are the same as in Example 12; finally, the bidentate nitrided nickel complex Ni10 is obtained with a yield of 86%.

[0169] MS(FAB,m / z):549.0(M++1).Anal.Calcd for C23H26BrN2Ni:C,50.32;H,4.77;Found:C,50.30;H,4.74.

[0170] ¹H NMR (CDCl₃, 400MHz) δ (ppm): 22.44 (s, Ar-H), 11.70 (br, Ar-H), 11.49 (br, Ar-H), 10.99 (dd, Ar-H), 8.05 (s, CH=N), 7.85 (m, Ar-H), 7.18–7.15 (m, Ar-H), 6.83 (d, Ar-H), 3.26 (s, Ar-CH₃), 2.58 (s, N(CH₃)₂), 2.40 (s, Ar-CH₃), 1.20 (s, C(CH₃)₂), -0.56 (s, N(CH₃)₂), -1.24 (s, C(CH₃)₂). Based on the integral ratio of N-CH₃, the ratio of the two isomers is 2.3:1.

[0171] Figure 1 This is the 1H NMR spectrum of the bidentate azahexane nickel complex of Example 20.

[0172] Example 21

[0173] This embodiment provides a bidentate nitrided nickel complex Ni11, the only difference between which is the synthesis method and that of Example 13, except that (DME)NiBr2 is used instead of (DME)NiCl2, and the other conditions are the same as in Example 13; finally, the bidentate nitrided nickel complex Ni11 is obtained with a yield of 86%.

[0174] MS(FAB,m / z):566.0(M++1).Anal.Calcd for C23H26Br2N2NiO:C,48.90;H,4.64;Found:C,48.91;H,4.64.

[0175] ¹H NMR (CDCl₃, 400MHz) δ (ppm): 22.44 (s, Ar-H), 11.70 (br, Ar-H), 11.49 (br, Ar-H), 10.99 (dd, Ar-H), 8.05 (s, CH=N), 7.85 (m, Ar-H), 7.18–7.15 (m, Ar-H), 6.83 (d, Ar-H), 3.76 (s, -OCH₃), 3.40 (s, -OCH₃), 2.58 (s, N(CH₃)₂), 1.21 (s, C(CH₃)₂), -0.54 (s, N(CH₃)₂), -1.24 (s, C(CH₃)₂). Based on the integral ratio of N-CH₃, the ratio of the two isomers is 2.2:1.

[0176] Example 22

[0177] This embodiment provides a bidentate nitrided nickel complex Ni12, the only difference between which is the synthesis method and that of Example 14, except that (DME)NiBr2 is used instead of (DME)NiCl2, and the other conditions are the same as in Example 14; finally, the bidentate nitrided nickel complex Ni12 is obtained with a yield of 86%.

[0178] MS(FAB,m / z):604.0(M++1).Anal.Calcd for C23H23Br2F3N2Ni:C,45.82;H,3.85;Found:C,45.85;H,3.84.

[0179] ¹H NMR (CDCl₃, 400MHz) δ (ppm): 22.44 (s, Ar-H), 11.90 (br, Ar-H), 11.79 (br, Ar-H), 10.99 (dd, Ar-H), 8.05 (s, CH=N), 7.85 (m, Ar-H), 7.18–7.15 (m, Ar-H), 6.83 (d, Ar-H), 3.26 (s, Ar-CH₃), 2.58 (s, N(CH₃)₂), 2.40 (s, Ar-CH₃), 1.20 (s, C(CH₃)₂), -0.56 (s, N(CH₃)₂), -1.24 (s, C(CH₃)₂). Based on the integral ratio of N-CH₃, the ratio of the two isomers is 2.3:1.

[0180] Example 23

[0181] This embodiment provides a bidentate nitrided nickel complex Ni13, the only difference between which is the synthesis method and that of Example 15, except that (DME)NiBr2 is used instead of (DME)NiCl2, and the other conditions are the same as in Example 15; finally, the bidentate nitrided nickel complex Ni13 is obtained with a yield of 83%.

[0182] MS(FAB,m / z):564.0(M++1).Anal.Calcd for C24H28Br2N2Ni:C,51.20;H,5.01;Found:C,51.22;H,5.03.

[0183] 1H NMR (CDCl3, 400MHz) δ (ppm): 8.01 (s, 1H, CH=N), 7.78 (dd, 1H, Ar-H), 7.70 (dd, 1H, Ar-H), 7.45-7.33 (m, 2H, Ar-H), 7.2 4-7.10(m,6H,Ar-H),6.68(dd,1H,Ar-H),2.10(q,4H,N(CH2CH3)2),0.67(s,6H,C(CH3)2),0.50(s,6H,N(CH2CH3)2).

[0184] Example 24

[0185] This embodiment provides a bidentate nitrided nickel complex Ni14, the only difference between which is the synthesis method and that of Example 16, except that (DME)NiBr2 is used instead of (DME)NiCl2, and the other conditions are the same as in Example 16; finally, the bidentate nitrided nickel complex Ni14 is obtained with a yield of 78%.

[0186] MS(FAB,m / z):578.0(M++1).Anal.Calcd for C25H30Br2N2Ni:C,52.04;H,5.24;Found:C,52.02;H,5.23.

[0187] 1H NMR (CDCl3, 400MHz) δ (ppm): 7.98 (s, 1H, CH=N), 7.84 (dd, 1H, Ar-H), 7.72 (dd, 1H, Ar-H), 7.40-7.33 (m, 2H, Ar-H), 7.24-7.12 (m, 5H,Ar-H), 6.66(dd,1H,Ar-H), 2.40(s,3H,Ar-CH3), 2.10(q,4H,N(CH2CH3)2), 0.66(s,6H,C(CH3)2), 0.53(s,6H,N(CH2CH3)2).

[0188] Example 25

[0189] This embodiment provides a bidentate nitrided nickel complex Ni15, the only difference between which is the synthesis method and that of Example 17, except that (DME)NiBr2 is used instead of (DME)NiCl2, and the other conditions are the same as in Example 17; finally, the bidentate nitrided nickel complex Ni15 is obtained with a yield of 83%.

[0190] MS(FAB,m / z):594.0(M++1).Anal.Calcd for C25H30Br2N2NiO:C,50.63;H,5.10;Found:C,50.60;H,5.13.

[0191] 1H NMR (CDCl3, 400MHz) δ (ppm): 7.99 (s, 1H, CH=N), 7.87 (dd, 1H, Ar-H), 7.73 (dd, 1H, Ar-H), 7.41-7.31 (m, 2H, Ar-H), 7.29-7.22 (m, 5H,Ar-H), 6.75(dd,1H,Ar-H), 3.35(s,3H,Ar-OCH3), 2.07(q,4H,N(CH2CH3)2), 0.68(s,6H,C(CH3)2), 0.56(s,6H,N(CH2CH3)2).

[0192] Example 26

[0193] This embodiment provides a bidentate nitrided nickel complex Ni16, the only difference between which is the synthesis method and that of Example 18, except that (DME)NiBr2 is used instead of (DME)NiCl2, and the other conditions are the same as in Example 18; finally, the bidentate nitrided nickel complex Ni16 is obtained with a yield of 79%.

[0194] MS(FAB,m / z):632.0(M++1).Anal.Calcd for C25H27Br2F3N2Ni:C,47.59;H,4.31;Found:C,47.61;H,4.30.

[0195] 1H NMR (CDCl3, 400MHz) δ (ppm): 8.01 (s, 1H, CH=N), 7.79 (dd, 1H, Ar-H), 7.53 (dd, 1H, Ar-H), 7.35-7.22 (m, 7 H,Ar-H), 6.69(dd,1H,Ar-H), 2.07(q,4H,N(CH2CH3)2), 0.69(s,6H,C(CH3)2), 0.64(s,6H,N(CH2CH3)2).

[0196] In the following examples, the catalyst activity calculation formula is as follows:

[0197] Activity = Mass of polyethylene oil / (Molar amount of nickel catalyst × Time).

[0198] Polyethylene oil was prepared, and the degree of branching was determined by nuclear magnetic resonance (NMR) using deuterated chloroform as solvent and tetramethylsilane as internal standard. The formula for calculating the degree of branching is as follows:

[0199] Br=(2I Me / 3I total )×1000,

[0200] Where I Me I is the integral area of ​​the methyl region. total The total integral area is denoted as .

[0201] Examples 27-42 below provide a method for preparing polyethylene using the above-described bidentate azide nickel complexes Ni1-Ni16 as a catalyst.

[0202] Example 27

[0203] This embodiment provides a method for preparing polyethylene oil, the specific steps of which are as follows:

[0204] The ethylene polymerization reaction was carried out in a stainless steel high-temperature and high-pressure reactor equipped with a stirrer. Before polymerization, the reactor was vacuum dried at 200°C for more than 2 hours. After the reactor cooled to room temperature, a toluene solution containing a co-catalyst was sequentially injected through the feed valve. Ethylene gas was introduced to a certain pressure, and the reaction system was heated to the set polymerization temperature and stirred thoroughly for 10 minutes. A toluene solution containing a nickel complex was added through the feed valve, and the total volume of the polymerization system was maintained at 70 mL. The pressure of ethylene was increased to the set pressure and kept constant throughout the polymerization process. After the polymerization reaction reached the set time, the ethylene supply was stopped, the pressure was slowly released, the reactor was opened, and 5% hydrochloric acid was added to the reactor to terminate the reaction, yielding a crude polyethylene oil product containing toluene. The crude product was washed with water and separated, then dried with anhydrous sodium sulfate, and then subjected to column chromatography with petroleum ether as the mobile phase to remove the ligands dissolved in the product. Finally, the solvent was removed by rotary evaporation to obtain polyethylene oil.

[0205] In this embodiment, the polymer conditions include: the nickel complex is the aforementioned bidentate aziridine nickel complex Ni1, with an amount of 1 μmol; the cocatalyst is modified methylaluminoxane (MMAO), and the Al / Ni molar ratio in the nickel metal combined catalyst (bidentate aziridine nickel complex + MMAO) is 400; the ethylene pressure is 10 atm, the polymerization temperature is 80°C, and the polymerization time is 30 minutes; the solvent is 70 mL of toluene.

[0206] Example 28

[0207] This embodiment provides a method for preparing polyethylene oil, which differs from Example 27 only in that the nickel complex is a bidentate azahexane nickel complex Ni2, and the other conditions are the same as in Example 27.

[0208] Example 29

[0209] This embodiment provides a method for preparing polyethylene oil, which differs from Example 27 only in that the nickel complex is a bidentate azahexane nickel complex Ni3, and the other conditions are the same as in Example 27.

[0210] Example 30

[0211] This embodiment provides a method for preparing polyethylene oil, which differs from Example 27 only in that the nickel complex is a bidentate azahexane nickel complex Ni4, and the other conditions are the same as in Example 27.

[0212] Example 31

[0213] This embodiment provides a method for preparing polyethylene oil, which differs from Example 27 only in that the nickel complex is a bidentate azahexane nickel complex Ni5, and the other conditions are the same as in Example 27.

[0214] Example 32

[0215] This embodiment provides a method for preparing polyethylene oil, which differs from Example 27 only in that the nickel complex is a bidentate azahexane nickel complex Ni6, and the other conditions are the same as in Example 27.

[0216] Example 33

[0217] This embodiment provides a method for preparing polyethylene oil, which differs from Example 27 only in that the nickel complex is a bidentate azahexane nickel complex Ni7, and the other conditions are the same as in Example 27.

[0218] Example 34

[0219] This embodiment provides a method for preparing polyethylene oil, which differs from Example 27 only in that the nickel complex is a bidentate azahexane nickel complex Ni8, and the other conditions are the same as in Example 27.

[0220] Example 35

[0221] This embodiment provides a method for preparing polyethylene oil, which differs from Example 27 only in that the nickel complex is a bidentate azahexane nickel complex Ni9, and the other conditions are the same as in Example 27.

[0222] Example 36

[0223] This embodiment provides a method for preparing polyethylene oil, which differs from Example 27 only in that the nickel complex is a bidentate azahexane nickel complex Ni10, while the other conditions are the same as in Example 27.

[0224] Example 37

[0225] This embodiment provides a method for preparing polyethylene oil, which differs from Example 27 only in that the nickel complex is a bidentate azahexane nickel complex Ni11, while the other conditions are the same as in Example 27.

[0226] Example 38

[0227] This embodiment provides a method for preparing polyethylene oil, which differs from Example 27 only in that the nickel complex is a bidentate azahexane nickel complex Ni12, and the other conditions are the same as in Example 27.

[0228] Example 39

[0229] This embodiment provides a method for preparing polyethylene oil, which differs from Example 27 only in that the nickel complex is a bidentate azahexane nickel complex Ni13, while the other conditions are the same as in Example 27.

[0230] Example 40

[0231] This embodiment provides a method for preparing polyethylene oil, which differs from Example 27 only in that the nickel complex is a bidentate azahexane nickel complex Ni14, while the other conditions are the same as in Example 27.

[0232] Example 41

[0233] This embodiment provides a method for preparing polyethylene oil, which differs from Example 27 only in that the nickel complex is a bidentate azahexane nickel complex Ni15, while the other conditions are the same as in Example 27.

[0234] Example 42

[0235] This embodiment provides a method for preparing polyethylene oil, which differs from Example 27 only in that the nickel complex is a bidentate azahexane nickel complex Ni16, while the other conditions are the same as in Example 27.

[0236] The results of catalytic ethylene polymerization in Examples 27-42 above are shown in Table 1.

[0237] Table 1. Results of ethylene polymerization catalyzed by the bidentate azahexane nickel complexes Ni1-Ni16 under the same conditions.

[0238]

[0239] As shown in Table 1, the nickel metal composite catalyst used in this invention exhibits high catalytic activity, a large yield of polyethylene, and a high degree of branching. Among them, under the same polymerization conditions, the bidentate azahexane nickel complex Ni10 shows the highest polymerization activity, reaching 4.7 × 10⁻⁶. 7 g / (mol Ni h), with Ni10 being the preferred complex.

[0240] Examples 43-45 below provide methods for preparing polyethylene oil by catalytic polymerization of ethylene using a bidentate azide nickel complex Ni10 and different alkyl aluminum combinations.

[0241] Example 43

[0242] This embodiment provides a method for preparing polyethylene oil, which differs from Example 36 only in that the co-catalyst is MAO, and the other conditions are the same as in Example 36.

[0243] Example 44

[0244] This embodiment provides a method for preparing polyethylene oil, which differs from Example 36 only in that the co-catalyst is Et2AlCl, and the other conditions are the same as in Example 36.

[0245] Example 45

[0246] This embodiment provides a method for preparing polyethylene oil, which differs from Example 36 only in that the co-catalyst is EtAlCl2, while the other conditions are the same as in Example 36.

[0247] The results of catalytic ethylene polymerization in Examples 43-45 and Example 36 are shown in Table 2.

[0248] Table 2. Ethylene polymerization results of the didentate azo-nickel complex Ni10 nickel complex under different cocatalysts.

[0249]

[0250] Comparison of the effects of different alkylaluminates on catalyst performance revealed that MMAO exhibited the highest activity when used as a co-catalyst, and the resulting polymer achieved a branching degree of 145 / 1000C. Therefore, MAO or MMAO is the preferred co-catalyst.

[0251] Examples 46-49 below provide methods for preparing polyethylene oil by catalytic polymerization of ethylene using nickel metal combined catalysts with different Al / Ni molar ratios.

[0252] Example 46

[0253] This embodiment provides a method for preparing polyethylene oil, which differs from Example 36 only in that the Al / Ni molar ratio is 100, while the other conditions are the same as in Example 36.

[0254] Example 47

[0255] This embodiment provides a method for preparing polyethylene oil, which differs from Example 36 only in that the Al / Ni molar ratio is 300, while the other conditions are the same as in Example 36.

[0256] Example 48

[0257] This embodiment provides a method for preparing polyethylene oil, which differs from Example 36 only in that the Al / Ni molar ratio is 600, while the other conditions are the same as in Example 36.

[0258] Example 49

[0259] This embodiment provides a method for preparing polyethylene oil, which differs from Example 36 only in that the Al / Ni molar ratio is 1000, while the other conditions are the same as in Example 36.

[0260] The results of preparing polyethylene oil in Examples 46-49 and Example 36 are shown in Table 3.

[0261] Table 3. Ethylene polymerization results at different Al / Ni molar ratios

[0262]

[0263] Examples 50-53 below provide methods for preparing polyethylene oil by catalyzing the polymerization of ethylene with nickel metal combined catalysts at different polymerization temperatures.

[0264] Example 50

[0265] This embodiment provides a method for preparing polyethylene oil, which differs from Example 36 only in that the polymerization temperature is 30°C, while the other conditions are the same as in Example 36.

[0266] Example 51

[0267] This embodiment provides a method for preparing polyethylene oil, which differs from Example 36 only in that the polymerization temperature is 50°C, while the other conditions are the same as in Example 36.

[0268] Example 52

[0269] This embodiment provides a method for preparing polyethylene oil, which differs from Example 36 only in that the polymerization temperature is 60°C, while the other conditions are the same as in Example 36.

[0270] Example 53

[0271] This embodiment provides a method for preparing polyethylene oil, which differs from Example 36 only in that the polymerization temperature is 100°C, while the other conditions are the same as in Example 36.

[0272] The results of preparing polyethylene oil in Examples 50-53 and Example 36 are shown in Table 4.

[0273] Table 4. Ethylene polymerization results at different polymerization temperatures.

[0274]

[0275] Examples 54-57 below provide a method for preparing polyethylene oil by catalytic polymerization of ethylene using a nickel metal combined catalyst under different ethylene pressures.

[0276] Example 54

[0277] This embodiment provides a method for preparing polyethylene oil, which differs from Example 36 only in that the ethylene pressure is 1 atm, while the other conditions are the same as in Example 36.

[0278] Example 55

[0279] This embodiment provides a method for preparing polyethylene oil, which differs from Example 36 only in that the ethylene pressure is 5 atm, while the other conditions are the same as in Example 36.

[0280] Example 56

[0281] This embodiment provides a method for preparing polyethylene oil, which differs from Example 36 only in that the ethylene pressure is 15 atm, while the other conditions are the same as in Example 36.

[0282] Example 57

[0283] This embodiment provides a method for preparing polyethylene oil, which differs from Example 36 only in that the ethylene pressure is 20 atm, while the other conditions are the same as in Example 36.

[0284] The results of preparing polyethylene oil in Examples 54-57 and Example 36 are shown in Table 5.

[0285] Table 5. Ethylene polymerization results under different ethylene pressures.

[0286]

[0287]

[0288] Comparative Example 1

[0289] This comparative example provides a method for preparing polyethylene oil, which differs from Example 36 (Ni10) only in the nickel complex; all other conditions are the same as in Example 27. The nickel complex used in this comparative example is an α-diimine nickel complex containing only one nitrogen (imine nitrogen) ligand, denoted as nickel complex Ni17, with the following structural formula:

[0290]

[0291] The α-diimine nickel complex Ni17 of this comparative example can be prepared according to the method reported in the literature (Synthesis of Highly BranCHedPolyethylene Using “SandwiCH” (8-p-Tolyl naphthylα-diimine)nickel(II)Catalysts[J]. Organometallics 2013,32(18),5136-5143).

[0292] Comparative Example 2

[0293] This comparative example provides a method for preparing polyethylene oil, which differs from Comparative Example 1 (Ni17) only in that the polymerization temperature is 50°C, while the other conditions are the same as those in Comparative Example 1.

[0294] The results of preparing polyethylene oil in Comparative Examples 1 and 2 are shown in Table 6 and compared with the results of Examples 36 and 37.

[0295] Table 6 Comparison of ethylene polymerization results between Ni17, Ni110, and Ni11

[0296]

[0297]

[0298] The data in Table 6 clearly show that the catalysts composed of Ni17 in Comparative Examples 1 and 2 have low activity, with an activity of only 5.6-7.8 × 10⁻⁶ at 80℃. 5 The activity of Ni17 catalyzed polyethylene was g / (mol Ni h), and the polyethylene obtained by Ni17 catalysis had a relatively lower degree of branching and a higher molecular weight, resulting in a solid polymer sample. Ni10 and Ni11 had approximately two orders of magnitude higher activity than Ni17, yielding highly branched polyethylene oil samples. Therefore, the steric hindrance strategy of "combining rigidity and flexibility" and "combining size" adopted in this invention—that is, using sterically hindered flexible alkyl groups as substituents for the amine groups in nickel complexes Ni1-Ni16, and using sterically hindered rigid bidentate aza-ligands for the imine groups as substituents—is highly feasible for catalytic ethylene polymerization to prepare highly branched polyethylene oil.

Claims

1. A method for preparing polyethylene oil, comprising: Ethylene is brought into full contact with a nickel metal composite catalyst and polymerized to obtain polyethylene oil; wherein the nickel metal composite catalyst comprises a main catalyst and a co-catalyst in a molar ratio of 1:100-1000, the co-catalyst being an alkylaluminum, and the main catalyst being a bidentate azahexane nickel complex having the structure shown in formula (I): R1 and R2 may be the same or different, and each is independently selected from substituted or unsubstituted C1-C. 10 Alkyl, C1-C 10 Alkoxy, C2-C 10 alkenyl or C6-C 10 Aryl; R3 is selected from hydrogen, methyl, methoxy, and trifluoromethyl; X is selected from chlorine or bromine.

2. The method for preparing polyethylene oil according to claim 1, wherein, In the bidentate azirmonotriazine nickel complex, R1 and R2 are each independently selected from methyl, ethyl, propenyl or phenyl, preferably methyl or ethyl.

3. The method for preparing polyethylene oil according to claim 1, wherein, In bidentate azahexane nickel complexes, R3 is selected from methoxy or methyl.

4. The method for preparing polyethylene oil according to claim 1, wherein, Didentate nitrogen-hexaned nickel complexes satisfy any one of the following conditions: R1 and R2 are both methyl groups, R3 is hydrogen, and X is chlorine. R1 and R2 are both methyl groups, R3 is methyl, and X is chlorine. R1 and R2 are both methyl groups, R3 is methoxy group, and X is chlorine. R1 and R2 are both methyl groups, R3 is trifluoromethyl, and X is chlorine. R1 and R2 are both ethyl groups, R3 is hydrogen, and X is chlorine. R1 and R2 are both ethyl groups, R3 is methyl, and X is chlorine. R1 and R2 are both ethyl groups, R3 is methoxy, and X is chlorine. R1 and R2 are both ethyl groups, R3 is trifluoromethyl, and X is chlorine. R1 and R2 are both methyl groups, R3 is hydrogen, and X is bromine; R1 and R2 are both methyl groups, R3 is methyl group, and X is bromine. R1 and R2 are both methyl groups, R3 is methoxy group, and X is bromine. R1 and R2 are both methyl groups, R3 is trifluoromethyl, and X is bromine; R1 and R2 are both ethyl groups, R3 is hydrogen, and X is bromine; R1 and R2 are both ethyl groups, R3 is a methyl group, and X is a bromine group; R1 and R2 are both ethyl groups, R3 is methoxy, and X is bromine. R1 and R2 are both ethyl groups, R3 is trifluoromethyl, and X is bromine.

5. The method for preparing polyethylene oil according to claim 1, wherein, The alkylaluminum includes methylaluminoxane, modified methylaluminoxane, diethylaluminum chloride, and diethylaluminum chloride.

6. The method for preparing polyethylene oil according to claim 1, wherein, During the polymerization reaction, the pressure of ethylene is 1-20 atm.

7. The method for preparing polyethylene oil according to claim 1, wherein, The polymerization reaction temperature is 20-150℃, and the polymerization reaction time is 0.5-8h.

8. The method for preparing polyethylene oil according to claim 1, wherein, During the polymerization reaction, a nickel metal composite catalyst is dispersed in a solvent, which includes one or more of alkanes, aromatics, halogenated hydrocarbons, and alkenes.

9. The method for preparing polyethylene oil according to claim 1, wherein, The method for preparing polyethylene oil further includes: using hydrochloric acid to terminate the polymerization reaction, thereby obtaining polyethylene oil.

10. The method for preparing polyethylene oil according to claim 1, wherein, The method for preparing polyethylene oil also includes purifying the terminated reaction solution; The purification steps include: washing the reaction solution with water, separating and drying it, then performing column chromatography, and finally removing the solvent to obtain polyethylene oil.

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