A heterometallic binuclear catalyst based on Schiff base ligands and its preparation method and application

Abstract

The present invention discloses a Schiff base ligand-based heterometallic binuclear catalyst, its preparation method, and application. The structural formula of the Schiff base ligand-based heterometallic binuclear catalyst is as follows: #imgabs0# wherein M is Ni or Pd, and R is -H or -CH3. The heterometallic binuclear catalyst is used to catalyze the copolymerization of olefins and polar monomers to prepare functionalized polyolefin materials. The present invention uses a Schiff base with good coordination ability as a ligand and adopts a bimetallic strategy to prepare the heterometallic binuclear catalyst. By regulating the steric hindrance of the ligand, different coordination environments are achieved, thereby optimizing the catalytic performance of the catalyst. The synergistic effect of the bimetallic center enables favorable regulation of the catalytic performance of the catalyst during the polymerization process, such as catalytic activity, polymer relative molecular weight and distribution, and copolymerization performance.

Description

Technical Field

[0001] The present invention relates to the field of catalytic olefins, and in particular to a heterometallic binuclear catalyst based on a Schiff base ligand, and a preparation method and application thereof. Background Art

[0002] Polyolefins are ubiquitous in everyday life, representing the largest annual production and most widely used polymer material. However, one of their greatest drawbacks is their non-polar nature. Introducing polar functional groups into the non-polar backbone of polyolefins can improve their compatibility with polar materials and significantly enhance their performance. Consequently, the copolymerization of olefins with polar monomers is sought to yield high-performance functionalized olefins. Catalysts play a crucial role in the copolymerization of olefins and polar monomers, and with the advancement of science and technology, the catalysts used to synthesize polyolefins are also evolving.

[0003] In recent years, catalyst research and development has focused on the design of ligand structures for monometallic catalysts, using strategies such as steric and electronic effects to regulate polymerization processes. With further research, inspired by multimetallic enzymes in biology, bimetallic catalysts have been developed and exhibit superior thermal stability and stereoregularity compared to mononuclear catalysts. Due to synergistic, geometric, or coupling effects, bimetallic catalysts exhibit superior catalytic activity compared to single-metal component catalysts. The type of active metal center further influences the catalytic activity of the catalyst through interactions with ligands and polar monomers. Summary of the Invention

[0004] The object of the present invention is to provide a heterometallic binuclear catalyst based on a Schiff base ligand, a preparation method and an application thereof, wherein the heterometallic binuclear catalyst is used to catalyze the copolymerization of olefins and polar monomers.

[0005] In one aspect of the present invention, a heterometallic binuclear catalyst based on a Schiff base ligand is provided. According to an embodiment of the present invention, the structural formula thereof is as follows:

[0006]

[0007] Wherein, M is Ni or Pd, and R is -H or -CH3.

[0008] In another aspect of the present invention, a method for preparing a heterometallic binuclear catalyst based on a Schiff base ligand is provided. According to an embodiment of the present invention, the method comprises the following steps:

[0009] (1) Synthesis of the ligand: Under a nitrogen atmosphere, a first reagent, glacial acetic acid, anhydrous ethanol, and pyridine-2-carboxaldehyde are heated and stirred, the solvent is removed in vacuo, and then the excess raw materials are removed by filtration under reduced pressure and washed with anhydrous ethanol. The product is recrystallized using methanol and petroleum ether, allowed to stand at low temperature, and the recrystallization solvent is removed in vacuo to obtain a powder product; wherein the first reagent is p-aminophenol or 3,5-dimethyl-4-aminophenol;

[0010] (2) Synthesis of the metal complex: Under a nitrogen atmosphere, the powder product is mixed and dissolved with anhydrous ethanol, and then a second reagent is added and stirred at room temperature. After the reaction is completed, the reaction solution is concentrated and the solid is precipitated with anhydrous ether. The supernatant is removed and washed and dried to obtain a metal complex; wherein the second reagent is palladium dichloride or nickel chloride hexahydrate;

[0011] (3) Synthesis of heterometallic binuclear catalyst: Under a nitrogen atmosphere, the metal complex is mixed and dissolved with dichloromethane, and then vanadium trichloride and triethylamine are added. The mixture is stirred at room temperature, and the solvent is removed in vacuo to obtain a solid powder. The solid powder is recrystallized with dichloromethane and n-hexane, and the recrystallization solvent is removed to obtain the heterometallic binuclear catalyst based on the Schiff base ligand.

[0012] In addition, the preparation method of a heterometallic binuclear catalyst based on a Schiff base ligand according to the above embodiment of the present invention may also have the following additional technical features:

[0013] In some embodiments of the present invention, in step (1), the molar ratio of the first reagent to pyridine-2-carboxaldehyde is 1-1.1:1, and the amount of glacial acetic acid used is 1-2 drops.

[0014] In some embodiments of the present invention, in step (1), the heating and stirring is reflux stirring in an oil bath for 8-12 hours, and the temperature of the oil bath is 76-80°C.

[0015] In some embodiments of the present invention, in step (2), the molar ratio of the second reagent to the powdered product is 1:1-1.1.

[0016] In some embodiments of the present invention, in step (2), the stirring time at room temperature is 20-24 hours.

[0017] In some embodiments of the present invention, in step (3), the molar ratio of vanadium trichloride to the metal complex is 1-1.1:1, the amount of triethylamine used is 1-2 drops, and the stirring time at room temperature is 20-24 hours.

[0018] The general synthesis formula of the heterometallic binuclear catalyst based on Schiff base ligand is as follows:

[0019]

[0020] Wherein, M is Ni or Pd, and R is -H or -CH3.

[0021] In another aspect, the present invention provides an application of a heterometallic binuclear catalyst based on a Schiff base ligand. According to an embodiment of the present invention, the heterometallic binuclear catalyst is used to catalyze the copolymerization of olefins and polar monomers to prepare functionalized polyolefin materials.

[0022] In addition, the application of a heterometallic binuclear catalyst based on a Schiff base ligand according to the above embodiment of the present invention may also have the following additional technical features:

[0023] In some embodiments of the present invention, the catalytic copolymerization of olefins and polar monomers includes the following steps: a co-catalyst, a polar monomer and a heterometallic binuclear catalyst based on a Schiff base ligand are sequentially injected into an anhydrous and oxygen-free high-pressure reactor while maintaining argon flow, an ethylene gas flow is introduced and stirring is started to carry out polymerization, after a certain period of time, the reaction solution is poured into an ethanol solution containing 4wt%-5wt% hydrochloric acid to precipitate a polymer, and the resulting product is washed with ethanol and then vacuum dried to constant weight to obtain a copolymer of ethylene and a polar monomer.

[0024] In some embodiments of the present invention, the polar monomer is one of 6-chloro-1-hexene, 10-undecene-1-ol, and 10-undecenoic acid methyl ester, the co-catalyst is diethylaluminum chloride, the polymerization is carried out in a toluene solution, the molar ratio of the heterometallic binuclear catalyst based on the Schiff base ligand to the polar monomer is 1:500-1500, the reaction temperature is 25-60°C, and the stirring reaction time is 5-10 min.

[0025] The general formula of the above-mentioned olefin coordination polymerization is as follows:

[0026]

[0027]

[0028] Wherein, M is Ni or Pd, and R is -H or -CH3.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] (1) The catalyst synthesis steps in the present invention are relatively simple, the raw materials used are cheap and easy to obtain, the reaction conditions are relatively mild, the reaction has no by-products and the product yield is relatively high.

[0031] (2) In the present invention, the spatial structure of the Schiff base ligand is regulated and the metal active center is protected by introducing steric groups, thereby effectively reducing the occurrence of side reactions and further improving the stability and catalytic activity of the catalyst.

[0032] (3) The present invention adopts a dual metal center strategy. The two metal centers enhance the catalytic activity of the catalyst through the electronic synergy between the ligands. Compared with single metal catalysts, the poisoning effect of the catalyst is greatly reduced and the catalytic activity is significantly improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 This is the H NMR spectrum of the Schiff base ligand 1 of pyridine-2-carboxaldehyde condensed with p-aminophenol in Example 1 of the present invention;

[0034] Figure 2 is the H NMR spectrum of the metal complex 1 in Example 1 of the present invention;

[0035] Figure 3 This is an infrared image of the heterometallic binuclear catalyst based on Schiff base ligands in Example 1 of the present invention;

[0036] Figure 4 This is the H NMR spectrum of the Schiff base ligand 2 of pyridine-2-carboxaldehyde 3,5-dimethyl-4-aminophenol in Example 2 of the present invention;

[0037] Figure 5 This is the H NMR spectrum of the metal complex 2 in Example 2 of the present invention;

[0038] Figure 6 This is an infrared image of the heterometallic binuclear catalyst based on Schiff base ligands in Example 2 of the present invention;

[0039] Figure 7 is an infrared image of the ethylene homopolymer in Example 4 of the present invention;

[0040] Figure 8 This is an infrared image of the copolymer of ethylene and 6-chloro-1-hexene in Example 5 of the present invention;

[0041] Figure 9 This is the infrared image of the copolymer of ethylene and 10-undecene-1-ol in Example 6 of the present invention. DETAILED DESCRIPTION

[0042] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0043] Example 1

[0044] A method for preparing a heterometallic binuclear catalyst based on a Schiff base ligand comprises the following steps:

[0045] (1) p-Aminophenol (1.09 g, 10 mmol) was weighed into a 250 mL round-bottom flask. Under nitrogen protection, anhydrous ethanol (20 mL), glacial acetic acid (0.1 mL) and pyridine-2-carboxaldehyde (1.07 g, 10 mmol) were added in sequence. The two-necked flask was placed in an oil bath and refluxed with stirring for 12 h. The solvent was removed under vacuum, and then filtered under reduced pressure and washed with anhydrous ethanol. The filter cake was dissolved in a small amount of slightly hot methanol, and petroleum ether was added to precipitate a yellow powder. The mixture was placed in a refrigerator at 0°C and allowed to stand for 4 h. The solvent was removed under vacuum to obtain 1.39 g of a yellow powder of pyridine-2-carboxaldehyde condensed p-aminophenol Schiff base ligand with a yield of 70.2%.

[0046] (2) Pyridine-2-carboxaldehyde condensed p-aminophenol Schiff base ligand 1 (198 mg, 1 mmol) was weighed into a 100 mL round-bottom flask, 10 mL of methanol was added thereto to dissolve, and then palladium dichloride (177 mg, 1 mmol, dissolved in 10 mL of methanol) was added thereto. The system was replaced with a nitrogen atmosphere, stirred at room temperature for 24 h to ensure that the reaction was complete, and then transferred to a single-necked flask. The reaction solution was concentrated to 3 mL, and anhydrous ether was added to precipitate the product and washed 3 times. The solvent was removed in vacuo to obtain metal complex 1 (yellow-brown powder 315 mg, yield 84%).

[0047] (3) In a glove box, metal complex 1 (37.5 mg, 0.1 mmol) was weighed and placed in a 20 mL screw-capped bottle. Dichloromethane (10 mL), VCl3 (15.7 mg, 0.1 mmol), and triethylamine (10 mg) were added. The reaction was stopped after stirring at room temperature for 24 h. The color of the solution changed from yellow to yellow-brown. After the reaction was completed, the product was transferred to a single-necked bottle and the solvent was removed under reduced pressure to obtain a yellow-brown solid. A small amount of DCM was added until the product was completely dissolved. 15 mL of n-hexane was added to precipitate the product. The supernatant was removed and the solvent was removed under reduced pressure to obtain a heterometallic binuclear catalyst cat.1 based on a Schiff base ligand (23 mg of yellow-brown powder, yield 46.3%). Its structural formula is shown below:

[0048]

[0049] Example 2

[0050] A method for preparing a heterometallic binuclear catalyst based on a Schiff base ligand comprises the following steps:

[0051] (1) 3,5-dimethyl-4-aminophenol (1.37 g, 10 mmol) was weighed into a 250 mL round-bottom flask. Under nitrogen protection, anhydrous ethanol (20 mL), glacial acetic acid (0.1 mL) and pyridine-2-carboxaldehyde (1.07 g, 10 mmol) were added in sequence. The two-necked flask was placed in an oil bath and refluxed with stirring for 12 h. The solvent was removed under vacuum and then filtered under reduced pressure and washed with anhydrous ethanol. The filter cake was dissolved in a small amount of slightly hot methanol and petroleum ether was added. A dark green powder was precipitated. The mixture was placed in a refrigerator at 0°C and allowed to stand for 4 h. The solvent was removed under vacuum to obtain 2.06 g of dark green powder pyridine-2-carboxaldehyde condensed with 3,5-dimethyl-4-aminophenol Schiff base ligand II with a yield of 91.2%.

[0052] (2) Pyridine-2-carboxaldehyde 3,5-dimethyl-4-aminophenol Schiff base ligand (226 mg, 1 mmol) was weighed into a 100 mL round-bottom flask, 10 mL of methanol was added thereto to dissolve, and then palladium dichloride (177 mg, 1 mmol, dissolved in 10 mL of methanol) was added thereto. The system was replaced with a nitrogen atmosphere, stirred at room temperature for 24 h to ensure that the reaction was complete, and then transferred to a single-necked bottle. The reaction solution was concentrated to 3 mL and anhydrous ether was added to precipitate the product and washed 3 times. The solvent was removed in vacuo to obtain metal complex II (317 mg of green powder, yield 78.7%).

[0053] (3) In a glove box, metal complex II (80.6 mg, 0.2 mmol) was weighed and placed in a 20 mL screw-capped bottle. Dichloromethane (10 mL), VCl3 (31.4 mg, 0.2 mmol), and triethylamine (10 mg) were added. The reaction was stopped after stirring at room temperature for 24 h. The color of the solution changed from purple to brown. After the reaction was completed, the product was transferred to a single-necked bottle and the solvent was removed under reduced pressure to obtain a dark brown solid. A small amount of DCM was added until the product was completely dissolved. 15 mL of n-hexane was added to precipitate the product. The supernatant was removed and the solvent was removed under reduced pressure to obtain a heterometallic binuclear catalyst cat.2 based on a Schiff base ligand (96 mg of dark brown powder, yield 91.4%). Its structural formula is shown below:

[0054]

[0055] Example 3

[0056] A method for preparing a heterometallic binuclear catalyst based on a Schiff base ligand comprises the following steps:

[0057] (1) 3,5-dimethyl-4-aminophenol (1.37 g, 10 mmol) was weighed into a 250 mL round-bottom flask. Under nitrogen protection, anhydrous ethanol (20 mL), glacial acetic acid (0.1 mL) and pyridine-2-carboxaldehyde (1.07 g, 10 mmol) were added in sequence. The two-necked flask was placed in an oil bath and refluxed with stirring for 12 h. The solvent was removed under vacuum and then filtered under reduced pressure and washed with anhydrous ethanol. The filter cake was dissolved in a small amount of slightly hot methanol and petroleum ether was added. A dark green powder was precipitated. The mixture was placed in a refrigerator at 0°C and allowed to stand for 4 h. The solvent was removed under vacuum to obtain 2.06 g of dark green powder pyridine-2-carboxaldehyde condensed with 3,5-dimethyl-4-aminophenol Schiff base ligand II with a yield of 91.2%.

[0058] (2) Pyridine-2-carboxaldehyde 3,5-dimethyl-4-aminophenol Schiff base ligand II (226 mg, 1 mmol) was weighed into a 100 mL round-bottom flask, 10 mL of methanol was added thereto to dissolve, and then nickel chloride hexahydrate (237 mg, 1 mmol, dissolved in 10 mL of methanol) was added thereto. The system was replaced with a nitrogen atmosphere, stirred at room temperature for 24 h to ensure that the reaction was complete, and then transferred to a single-necked flask. The reaction solution was concentrated to 3 mL and anhydrous ether was added to precipitate the product and washed 3 times. The solvent was removed in vacuo to obtain metal complex III (orange-yellow powder 293 mg, yield 82.4%).

[0059] (3) In a glove box, metal complex III (106.7 mg, 0.3 mmol) was weighed and placed in a 20 mL screw-capped bottle. Dichloromethane (10 mL), VCl3 (47.1 mg, 0.3 mmol), and triethylamine (10 mg) were added. The reaction was stopped after stirring at room temperature for 24 h. The color of the solution changed from purple to brownish yellow. After the reaction was completed, the product was transferred to a single-necked bottle and the solvent was removed under reduced pressure to obtain a brownish yellow solid. A small amount of DCM was added until the product was completely dissolved. 15 mL of n-hexane was added to precipitate the product. The supernatant was removed and the solvent was removed under reduced pressure to obtain a heterometallic binuclear catalyst cat.3 based on a Schiff base ligand (140 mg of brownish yellow powder, yield 98.02%). Its structural formula is shown below:

[0060]

[0061] Example 4

[0062] The ethylene homopolymerization method comprises the following steps:

[0063] In a glove box, weigh 2 μmol of the Schiff base ligand-based heterometallic binuclear catalyst cat.1 (primary catalyst) prepared in Example 1 into a 10 mL Schlenk flask, add 2 mL of dichloromethane to dissolve, and add 3 mL of toluene; weigh 1 mmol of the co-catalyst diethylaluminum chloride into a 25 mL Schlenk flask, add 5 mL of toluene; ensure that the total volume of toluene is 10 mL. Seal the two Schlenk flasks with sealing film and take them out of the glove box. Connect a double row of pipes and replace the gas in the pipes. After replacing three times, use a syringe to inject the co-catalyst diethylaluminum chloride and catalyst cat.1 into the reactor in sequence while ensuring argon flow. Dry the reactor in an oven for 12 hours and evacuate before use.

[0064] Ethylene gas at a pressure of 4 atm was introduced into the autoclave. The valve above the autoclave was opened to purge nitrogen from the autoclave. The reaction was initiated with magnetic stirring for 10 minutes. After the reaction was complete, the main valve of the ethylene cylinder was closed, the pressure was released, and the autoclave was disassembled. The reaction mixture in the autoclave was poured into 50 mL of 5% hydrochloric acid in ethanol. After stirring for 12 hours, the white solid was collected and vacuum-dried at 50°C to constant weight to obtain an ethylene homopolymer.

[0065] Example 5

[0066] The copolymerization method of ethylene and 6-chloro-1-hexene comprises the following steps:

[0067] In a glove box, weigh 2 μmol of the Schiff base ligand-based heterometallic binuclear catalyst cat.2 (primary catalyst) prepared in Example 2 into a 10 mL Schlenk flask and dissolve it in 2 mL of dichloromethane; weigh 1 mmol of the co-catalyst diethylaluminum chloride into a 25 mL Schlenk flask and add 5 mL of toluene; weigh 236 mg of 6-chloro-1-hexene (2.0 mmol) into a 25 mL Schlenk flask and add 5 mL of toluene, ensuring that the total volume of toluene is 10 mL. Seal the three Schlenk flasks with sealing film and take them out of the glove box. Connect a double row of pipes and replace the gas in the pipes. After replacing three times, use a syringe to inject the co-catalyst diethylaluminum chloride, the polar monomer 6-chloro-1-hexene, and the primary catalyst cat.2 into the reactor in sequence while ensuring argon flow. The reactor was oven-dried for 12 hours and evacuated before use.

[0068] Ethylene gas at a pressure of 4 atm was introduced into the kettle. The valve above the kettle was opened to purge nitrogen from the kettle. The reaction was initiated with magnetic stirring for 10 minutes. After the reaction was complete, the main valve of the ethylene cylinder was closed, the pressure was released, and the kettle was disassembled. The reaction mixture in the kettle was poured into 50 mL of ethanol containing 5% hydrochloric acid. After stirring for 12 hours, the white solid was collected and dried under vacuum at 50°C to constant weight to obtain a copolymer of ethylene and 6-chloro-1-hexene.

[0069] Example 6

[0070] The copolymerization method of ethylene and 10-undecene-1-ol comprises the following steps:

[0071] In the glove box, weigh 2 μmol of the Schiff base ligand-based heterometallic binuclear catalytic cat.2 (main catalyst) prepared in Example 2 into a 10 mL schlenk bottle and add 2 mL of dichloromethane to dissolve; weigh 1 mmol of the co-catalyst diethylaluminum chloride into a 25 mL schlenk bottle and add 5 mL of toluene; weigh 10-undecene-1-ol (340 mg, 2.0 mmol) into a 25 mL schlenk bottle and add 5 mL of toluene to ensure that the total volume of toluene is 10 mL. Seal the three schlenk bottles with sealing film and take them out of the glove box. Connect the double-row tube and replace the gas in the pipeline. After replacing three times, use a syringe to inject the co-catalyst diethylaluminum chloride, the polar monomer 10-undecene-1-ol, and the main catalyst cat.2 into the reactor in sequence while ensuring argon. The reactor was dried in an oven for 12 hours before use and vacuumed.

[0072] Ethylene gas at a pressure of 4 atm was introduced into the kettle. The valve above the kettle was opened to purge nitrogen from the kettle. The reaction was initiated with magnetic stirring for 10 minutes. After the reaction was complete, the main valve of the ethylene cylinder was closed, the pressure was released, and the kettle was disassembled. The reaction mixture in the kettle was poured into 50 mL of ethanol containing 5% hydrochloric acid. After stirring for 12 hours, the white solid was collected and dried under vacuum at 50°C to constant weight to obtain a copolymer of ethylene and 10-undecen-1-ol.

[0073] The above contents are merely examples and explanations of the present invention. Those skilled in the art may make various modifications or additions to the described specific embodiments or replace them in similar ways. As long as they do not deviate from the structure of the present invention or exceed the scope defined by the claims, they shall fall within the scope of protection of the present invention.

Claims

1. A heterometallic binuclear catalyst based on a Schiff base ligand, characterized in that: The structural formula is as follows: ， Wherein, M is Ni or Pd, and R is -H or -CH3.

2. A method for preparing a heterometallic binuclear catalyst based on a Schiff base ligand according to claim 1, characterized in that: The following steps are involved: (1) Synthesis of the ligand: Under a nitrogen atmosphere, the first reagent, glacial acetic acid, anhydrous ethanol, and pyridine-2-carboxaldehyde are heated and stirred, the solvent is removed in vacuo, and then the excess raw materials are removed by filtration under reduced pressure and washed with anhydrous ethanol. The product is recrystallized using methanol and petroleum ether, allowed to stand at low temperature, and the recrystallization solvent is removed in vacuo to obtain a powder product; wherein the first reagent is p-aminophenol or 3,5-dimethyl-4-aminophenol; (2) Synthesis of metal complex: Under a nitrogen atmosphere, the powder product is mixed and dissolved with anhydrous ethanol, and then a second reagent is added and stirred at room temperature. After the reaction is completed, the reaction solution is concentrated and the solid is precipitated with anhydrous ether. The supernatant is removed and washed and dried to obtain a metal complex; wherein the second reagent is palladium dichloride or nickel chloride hexahydrate; (3) Synthesis of heterometallic binuclear catalyst: Under a nitrogen atmosphere, the metal complex is mixed and dissolved with dichloromethane, and then vanadium trichloride and triethylamine are added. The mixture is stirred at room temperature, and the solvent is removed in vacuo to obtain a solid powder. The solid powder is recrystallized with dichloromethane and n-hexane, and the heterometallic binuclear catalyst based on the Schiff base ligand is obtained after removing the recrystallization solvent.

3. The preparation method according to claim 2, wherein: In the step (1), the molar ratio of the first reagent to pyridine-2-carboxaldehyde is 1-1.1:

1.

4. The preparation method according to claim 2, wherein: In the step (1), the heating and stirring is performed by reflux stirring in an oil bath for 8-12 h, and the temperature of the oil bath is 76-80°C.

5. The preparation method according to claim 2, wherein: In the step (2), the molar ratio of the second reagent to the powder product is 1:1-1.

1.

6. The preparation method according to claim 2, wherein: In the step (2), the stirring time at room temperature is 20-24 h.

7. The preparation method according to claim 2, characterized in that: In the step (3), the molar ratio of vanadium trichloride to the metal complex is 1-1.1:1, and the stirring time at room temperature is 20-24 h.

8. Use of the heterometallic binuclear catalyst based on Schiff base ligands according to claim 1, characterized in that: The heterometallic binuclear catalyst is used to catalyze the copolymerization of olefins and polar monomers to prepare functionalized polyolefin materials.

9. The use according to claim 8, characterized in that The catalytic copolymerization of olefins and polar monomers comprises the following steps: a co-catalyst, a polar monomer, and a heterometallic binuclear catalyst based on a Schiff base ligand are sequentially injected into an anhydrous and oxygen-free high-pressure reactor while maintaining argon flow, an ethylene flow is introduced, and stirring is started to carry out polymerization, after a certain period of time, the reaction solution is poured into an ethanol solution containing 4 wt%-5 wt% hydrochloric acid to precipitate a polymer, and the resulting product is washed with ethanol and then vacuum dried to a constant weight to obtain a copolymer of ethylene and the polar monomer.

10. The use according to claim 9, characterized in that: The polar monomer is one of 6-chloro-1-hexene, 10-undecene-1-ol, and 10-undecenoic acid methyl ester; the cocatalyst is diethylaluminum chloride; the polymerization is carried out in a toluene solution; the molar ratio of the heterometallic binuclear catalyst based on the Schiff base ligand to the polar monomer is 1:500-1500; the polymerization temperature is 25-60°C; and the stirring time is 5-10 minutes.

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