A composite catalyst and its use in copolymerization, a copolymerization process, a copolymer

Abstract

The application provides a composite catalyst and application of the composite catalyst in copolymerization, a copolymerization method and a copolymer, the composite catalyst comprising a main catalyst and a cocatalyst, the main catalyst comprising an alpha-diimine post-transition metal complex and a bis-salicylaldehyde imine post-transition metal complex; and the cocatalyst comprising an organic aluminum compound. The application realizes copolymerization of ethylene and propylene acid ester by compounding the alpha-diimine post-transition metal complex and the bis-salicylaldehyde imine post-transition metal complex, and the copolymerization activity is high, and the molecular weight of the obtained copolymer is high.

Description

Technical Field

[0001] This invention relates to the field of copolymerization technology, specifically to a composite catalyst and its application in copolymerization, copolymerization methods, and copolymers. Background Technology

[0002] Compared to polyethylene, vinyl polar polymers exhibit better adhesion to other resins, especially polar engineering resins, and are therefore receiving increasing attention. Currently, vinyl polar polymers are mainly produced using high-pressure free radical polymerization technology, with reaction pressures of 150-300 MPa and reaction temperatures of 150-300 °C. These stringent process conditions and high safety requirements make the development of efficient methods for achieving ethylene polar copolymerization under moderate conditions a research hotspot. Post-transition metal catalysts have weak oxygen affinity and exhibit strong tolerance to heteroatoms in polar monomers, enabling them to catalyze the copolymerization of ethylene and acrylate monomers under low-pressure conditions via coordination polymerization. However, the copolymerization of ethylene and methyl methacrylate remains a technical challenge. This is mainly because methyl methacrylate has greater steric hindrance compared to other acrylate polar monomers, resulting in low copolymerization activity, lower molecular weight of the copolymer, and a low methyl methacrylate insertion rate in the copolymer.

[0003] There are three main existing copolymerization technologies for ethylene and methyl methacrylate. One method uses only one post-transition metal catalyst, achieving copolymerization of ethylene and methyl methacrylate under conditions where the molar ratio of the co-catalyst organoaluminum compound to the main catalyst metal is ≤1000:1. For example, CN201810651264.1 discloses a method for copolymerizing ethylene and methyl methacrylate using a salicylaldehyde-imine post-transition metal catalyst. However, the copolymerization activity of this method is generally only 10. 3 -10 4 g / molcat, and the weight-average molecular weight of the resulting copolymers is generally only 10. 4 g / mol; secondly, methyl methacrylate is first protected with alkyl aluminum before copolymerization with ethylene. For example, Chien et al. used an α-diimine nickel / methylaluminoxane catalyst system, first protecting methyl methacrylate with alkyl aluminum before copolymerization with ethylene. This method has higher copolymerization activity, reaching 10 g / mol. 5gPolymer / molcat[Polym.Int.,2001,50:579-587], however, the consumption of the co-catalyst in this method is also greatly increased, and the molar ratio of organoaluminum compound to main catalyst reaches more than 1000:1; thirdly, the combination of two different types of catalysts is currently mainly used for the homopolymerization of olefins. For example, Gao Rong et al. used nickel diimide as catalyst A, zirconium dichloride diisocyanate as catalyst B, and ethylene as monomer to obtain ethylene block polymers rich in soft segments [Synthetic Resins and Plastics,2020,37(3):6-10]. However, the catalysts involved in this technology are mainly used for catalyzing the homopolymerization reaction of ethylene and are not applicable to the copolymerization reaction of ethylene and methyl methacrylate. In addition, CN107868158A and CN108264595B disclose the use of different types of catalysts in the copolymerization of ethylene and methyl methacrylate, with a copolymerization activity of 10. 7 The catalyst composition is complex, and its preparation process is cumbersome. Furthermore, the molecular weight distribution of the resulting copolymer has not been reported. There are no publicly available reports on the use of similar catalysts in the copolymerization of ethylene and methyl methacrylate. Summary of the Invention

[0004] To address the technical problems of low copolymerization activity, low molecular weight of the resulting copolymers, and limited applications in existing coordination polymerization methods, this invention aims to provide a composite catalyst and its application in copolymerization, a copolymerization method, and a copolymer. The invention combines two catalysts, an α-diimine-type post-transition metal complex and a bis(salicylaldehyde)-imine-type post-transition metal complex, to achieve copolymerization of ethylene and acrylates, resulting in high copolymerization activity and high molecular weight copolymers.

[0005] To achieve the above objectives, the first aspect of the present invention provides a composite catalyst comprising a main catalyst and a co-catalyst, wherein the main catalyst comprises an α-diimine post-transition metal complex and a bis(salicylaldehyde) imine post-transition metal complex.

[0006] The α-diimine post-transition metal complex is selected from one or more compounds having the general formula shown in formula (I).

[0007]

[0008] In formula (I), R1 and R2 are the same or different aryl groups, with a first substituent attached to the ortho position of the C bonded to N on the aryl group and a second substituent attached to the para position of the C bonded to N. The first substituent is selected from hydrogen, C1-C2 alkyl, C1-C2 alkoxy, or hydroxyl, and the second substituent is selected from C1-C2 alkyl, alkylamino, alkoxy, amino, or hydroxyl. R3 and R4 are the same or different, and each of R3 and R4 is independently selected from hydrogen or C1-C4 alkyl. M1 is selected from Ni or Pd. X1 and X2 are the same or different, and each of X1 and X2 is independently selected from halogen, C2-C4 ether, or C1-C4 nitrile.

[0009] The bis-salicylaldehyde imine post-transition metal complex is selected from one or more compounds having the general formula shown in formula (II).

[0010]

[0011] In formula (II), R5 and R6 may be the same or different, and each of R5 and R6 is independently selected from hydrogen, C1-C2 alkyl, C1-C2 alkoxy or hydroxyl; R7 and R8 may be the same or different, and each of R7 and R8 is independently selected from hydrogen, C1-C6 alkyl, C1-C6 alkoxy, hydroxyl or aryl; M2 is selected from Ni or Pd.

[0012] This invention employs a combination of an α-diimine post-transition metal complex and a bis(salicylaldehyde) imine post-transition metal complex as the main catalyst. The α-diimine post-transition metal complex contains sterically hindered ligands, wherein the C at the ortho position of the C on the aryl group connected to N has a sterically hindered substituent, and the C at the para position of the C on the aryl group connected to N has a heteroatom-type electron-donating group. The bis(salicylaldehyde) imine post-transition metal complex contains sterically hindered ligands. By reducing the steric hindrance of the catalyst ligands, the complexation and coordination of methyl methacrylate and the active center are facilitated, thereby improving the copolymerization activity and extending the copolymerization time to obtain a high molecular weight copolymer.

[0013] According to a specific embodiment of the present invention, in formula (I), preferably, the first substituent is selected from hydrogen, methyl or ethyl.

[0014] According to a specific embodiment of the present invention, in formula (I), preferably, the second substituent is selected from C1-C2 alkyl, C1-C2 alkoxy or amino.

[0015] According to a specific embodiment of the present invention, in formula (I), preferably, R3 and R4 are each independently selected from hydrogen and C1-C2 alkyl groups.

[0016] According to a specific embodiment of the present invention, in formula (I), preferably, M1 is Ni.

[0017] According to a specific embodiment of the present invention, in formula (II), preferably, R7 and R8 are each independently selected from hydrogen, C1-C2 alkyl, and C1-C2 alkoxy.

[0018] According to a specific embodiment of the present invention, in formula (II), preferably, M2 is Ni.

[0019] According to a specific embodiment of the present invention, in the above-mentioned composite catalyst, preferably, the molar ratio of the α-diimine post-transition metal complex and the bis-salicylaldehyde imine post-transition metal complex is 1:49-49:1, more preferably 1:10-10:1.

[0020] According to a specific embodiment of the present invention, in the above-mentioned composite catalyst, preferably, the co-catalyst includes an organoaluminum compound, wherein the organoaluminum compound is selected from methylaluminoxane, alkylaluminum, sesquialkylaluminum, and more preferably sesquiethylaluminum, triethylaluminum, or methylaluminoxane.

[0021] According to a specific embodiment of the present invention, in the above-mentioned composite catalyst, preferably, the molar ratio of aluminum in the co-catalyst to the total metal content in the main catalyst is 50-1000:1, more preferably 100-500:1.

[0022] A second aspect of the present invention provides the application of the above-mentioned composite catalyst in the copolymerization of ethylene and acrylates.

[0023] According to a specific embodiment of the present invention, in the above application, preferably, the acrylate is methyl methacrylate.

[0024] A third aspect of the present invention provides a method for copolymerizing ethylene with methyl methacrylate, comprising the following steps:

[0025] In an ethylene atmosphere, methyl methacrylate and the above-mentioned composite catalyst are brought into full contact in an organic solvent to carry out a copolymerization reaction of ethylene and methyl methacrylate. After terminating the reaction, a copolymer is obtained.

[0026] According to a specific embodiment of the present invention, preferably, the copolymerization method further includes: after terminating the reaction, filtering, washing and drying the reaction solution to obtain the copolymer.

[0027] According to a specific embodiment of the present invention, in the above copolymerization method, preferably, the copolymerization reaction pressure is 0.05-10 MPa, more preferably 0.8-5 MPa.

[0028] According to a specific embodiment of the present invention, in the above copolymerization method, preferably, the copolymerization reaction temperature is 0-80℃, more preferably 30-60℃.

[0029] According to a specific embodiment of the present invention, in the above copolymerization method, preferably, the copolymerization reaction time is 0.1-24h, more preferably 0.5-12h.

[0030] According to a specific embodiment of the present invention, in the above copolymerization method, preferably, the concentration of methyl methacrylate in the reaction system is 0.01-6.0M, more preferably 0.1-5.0M.

[0031] According to a specific embodiment of the present invention, in the above copolymerization method, preferably, the terminating agent used to terminate the reaction is a hydrochloric acid ethanol solution, more preferably a hydrochloric acid ethanol solution with a volume fraction of 5%.

[0032] According to a specific embodiment of the present invention, in the above copolymerization method, preferably, the organic solvent is selected from one or a combination of two or more of toluene, n-hexane, cyclohexane, dichloromethane, dichloroethane, chlorobenzene, etc.

[0033] According to a specific embodiment of the present invention, in the above copolymerization method, preferably, when the organic solvent is selected from a combination of two solvents, the mixing volume ratio is 10:1-1:10.

[0034] According to a specific embodiment of the present invention, preferably, the above copolymerization method is carried out by any one of the following two embodiments:

[0035] Method 1:

[0036] In a clean and dry reactor, under an ethylene atmosphere, a solvent, an α-diimine post-transition metal complex (compound I), and a bis(salicylaldehyde) imine post-transition metal complex (compound II) are simultaneously added. The molar ratio of compound I to compound II is (1-49):(1-49), preferably (1-10):(1-10). The temperature is controlled at 0-80°C, preferably 30-60°C. After ethylene is introduced to saturation, an organoaluminum compound is added. The molar ratio of aluminum in the organoaluminum compound to the total metals in compound I and compound II is 50-1000:1, preferably 100-500:1. Ethylene is continued to be introduced, and the reaction pressure is controlled at 0.05-10 MPa, preferably 0.8-5 MPa. Methyl methacrylate is added. The concentration of methyl methacrylate is 0.01-6.0 M, preferably 0.1-5.0 M. The total reaction time is 0.1-24 hours, preferably 1-12 hours; after depressurization, a 5% (v / v) hydrochloric acid-ethanol solution is added to terminate the reaction. The reaction solution is then filtered, washed, and dried to obtain the copolymer.

[0037] Method 2:

[0038] In a clean and dry reactor, under an ethylene atmosphere, a solvent and an α-diimide transition metal complex (compound I) are added, with the temperature controlled at 0-80°C, preferably 30-60°C. After ethylene is introduced to saturation, a portion of an organoaluminum compound is added, and ethylene is continued to be introduced, with the pressure controlled at 0.05-10 MPa, preferably 0.8-5 MPa. A bis(salicylic acid) imide transition metal complex (compound II) and a portion of an organoaluminum compound are added, with the molar ratio of (I) to (II) being (1-50):(1-50), preferably (…). 1-10):(1-10); The molar ratio of aluminum in the two added organoaluminum compounds to the total metals in compounds I and II is 50-1000:1, preferably 100-500:1. Methyl methacrylate is added at a concentration of 0.01-6.0 M, preferably 0.1-5.0 M. The total reaction time is 0.1-24 hours, preferably 1-12 hours. The pressure is released, and the reaction is terminated by adding a 5% (v / v) hydrochloric acid ethanol solution. The reaction solution is filtered, washed, and dried to obtain the copolymer.

[0039] A fourth aspect of the present invention provides a copolymer obtained by the above-described copolymerization method.

[0040] According to a specific embodiment of the present invention, preferably, the weight-average molecular weight of the copolymer is ≥1×10⁻⁶. 5 g / mol.

[0041] The composite catalyst of the present invention, its application in copolymerization, and the copolymerization method thereof have the following beneficial effects:

[0042] (1) This invention employs a combination of two main catalysts: an α-diimine-type post-transition metal complex and a bis-salicylaldehyde-imine-type post-transition metal complex, both with specific structures and synergistic effects. With the aid of a co-catalyst, and leveraging the advantages of both main catalysts in achieving copolymerization of ethylene and methyl methacrylate while maintaining their respective advantages in the polymerization rates of different monomers, copolymerization of ethylene and methyl methacrylate is achieved at a relatively low molar ratio of co-catalyst to main catalyst. The copolymerization activity can reach 10. 5 g / molcat, and the molecular weight of the copolymer reaches 10. 5 g / mol;

[0043] (2) Currently, high-pressure free radical polymerization is used in industry to produce ethylene-methyl methacrylate copolymers or ethylene-acrylate copolymers, with a reaction pressure of 150-300 MPa and a reaction temperature of 150-300 °C. This invention uses coordination polymerization, with a composite of α-diimide post-transition metal catalyst and bis-salicylaldehyde imide post-transition metal catalyst, to achieve highly active copolymerization of ethylene and methyl methacrylate, with a reaction pressure ≤10 MPa and a reaction temperature ≤100 °C. Compared with existing industrial production methods, the reaction pressure of this invention is reduced by more than 10 times, and the reaction temperature is also significantly reduced.

[0044] (3) Compared with coordination polymerization using a single catalyst, this invention uses a combination of two post-transition metal catalysts with low steric hindrance. The rigid aromatic ring of the salicylaldehyde imine catalyst is very close to the active center, and the electronic effect on the aromatic ring has a great influence on the active center. Since the aromatic ring is an electron donor, the active center is more likely to insert and coordinate with the negatively charged polar monomer to reach equilibrium. Under the premise of taking advantage of the strong tolerance of the post-transition metal catalyst to polar monomers, the steric hindrance of the ligand space can provide sufficient space for methyl methacrylate to move, accelerate the equilibrium of methyl methacrylate and the complexation coordination speed of the active center. Under the same conditions, the copolymerization activity of this invention is equivalent to or more than 10 times higher, and the molecular weight of the copolymer of ethylene and methyl methacrylate is more than 10 times higher. Detailed Implementation

[0045] 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.

[0046] In this invention, the catalytic activity is the mass of copolymer generated per unit molar amount of catalyst per unit time, and the unit of catalytic activity is gPolymer / molM·h, where M refers to the total amount of metal in the catalyst.

[0047] In this embodiment of the invention, the α-diimine post-transition metal complex is compound I or compound II, and the bis(salicylaldehyde) imine post-transition metal complex is compound III or compound IV. The structures of compounds I-IV are as follows.

[0048]

[0049]

[0050] Example 1

[0051] This embodiment provides a method for copolymerizing ethylene with methyl methacrylate (MMA), comprising the following steps:

[0052] In a clean, dry 250 mL autoclave, under an ethylene atmosphere, add 100 mL of toluene, 39.2 μmol of [2,6-(C2H5)2-4-OCH3-C6H3-N=C(CH3)-C(CH3)=N-2,6-(C2H5)2-4-OCH3-C6H3]NiBr2 (compound I), and 0 μmol of [O-C6H4-oC(H)=N-2,6-(OCH3)2C6H3]2Ni (compound II). 0.8 μmol of ethylene was introduced until saturation, and the mixture was kept at a constant temperature of 60°C in an oil bath with electromagnetic stirring. After ethylene saturation, 10 mmol of methyl methacrylate and 26 mL (1.53 M) of methylaluminoxane (MAO) were added. ethylene was continued to be introduced while maintaining the ethylene pressure at 2 MPa. After 3 hours of reaction, the ethylene supply was stopped, the pressure was released, and the mixture was treated with a 5% hydrochloric acid-ethanol solution. After washing, filtration, and drying, 22.8 g of copolymer was obtained, with a catalytic activity of 1.9 × 10⁻⁸. 5 The copolymer has a weight-average molecular weight of 58.2 × 10⁻⁶ gPolymer / molNi·h. 4 g / mol, with a methyl methacrylate insertion rate of 4.1 mol%.

[0053] Example 2

[0054] This embodiment provides a method for copolymerizing ethylene with methyl methacrylate, comprising the following steps:

[0055] In a clean, dry 250 mL autoclave, under an ethylene atmosphere, add 100 mL of toluene, 0.8 μmol of [2,6-(C2H5)2-4-OCH3-C6H3-N=C(CH3)-C(CH3)=N-2,6-(C2H5)2-4-OCH3-C6H3]NiBr2 (compound I), and 39.2 μmol of [O-C6H4-oC(H)=N-2,6-(OCH3)2C6H3]2Ni (compound II). Purge with ethylene until saturated, and simultaneously maintain the temperature in a 60 °C oil bath with electromagnetic stirring. After ethylene saturation, add 10 mmol of methyl methacrylate and MAO. 26 mL (1.53 M) of ethylene was continuously introduced, maintaining an ethylene pressure of 2 MPa. After reacting for 3 hours, the ethylene supply was stopped, the pressure was released, and the mixture was treated with a 5% hydrochloric acid-ethanol solution. After washing, filtration, and drying, 12 g of the copolymer was obtained, with a catalytic activity of 1.0 × 10⁻⁶. 5 The copolymer has a weight-average molecular weight of 18.2 × 10⁻⁶ gPolymer / molNi·h. 4 g / mol, with a methyl methacrylate insertion rate of 24.1 mol%.

[0056] Example 3

[0057] This embodiment provides a method for copolymerizing ethylene with methyl methacrylate, comprising the following steps:

[0058] In a clean, dry 250 mL autoclave, under an ethylene atmosphere, add 100 mL of toluene, 36.4 μmol of [2,6-(C2H5)2-4-OCH3-C6H3-N=C(CH3)-C(CH3)=N-2,6-(C2H5)2-4-OCH3-C6H3]NiBr2 (compound I), and 3.6 μmol of [O-C6H4-oC(H)=N-2,6-(OCH3)2C6H3]2Ni (compound II). Pour ethylene through the autoclave until saturation, and simultaneously maintain the temperature in a 60 °C oil bath with electromagnetic stirring. After ethylene saturation, 10 mmol of methyl methacrylate and 13 mL of methylaluminoxane (1.53 M) were added. Ethylene was continued to be introduced while maintaining the ethylene pressure at 2 MPa. After reacting for 3 hours, the ethylene supply was stopped, the pressure was released, and the mixture was treated with a 5% hydrochloric acid-ethanol solution. After washing, filtration, and drying, 67.2 g of copolymer was obtained, with a catalytic activity of 5.6 × 10⁻⁶. 5 The copolymer has a weight-average molecular weight of 32.1 × 10⁻⁶ gPolymer / molNi·h. 4 g / mol, with a methyl methacrylate insertion rate of 5.2 mol%.

[0059] Example 4

[0060] This embodiment provides a method for copolymerizing ethylene with methyl methacrylate, comprising the following steps:

[0061] In a clean, dry 250 mL autoclave, under an ethylene atmosphere, add 100 mL of toluene, 3.6 μmol of [2,6-(C2H5)2-4-OCH3-C6H3-N=C(CH3)-C(CH3)=N-2,6-(C2H5)2-4-OCH3-C6H3]NiBr2 (compound I), and 36.4 μmol of [O-C6H4-oC(H)=N-2,6-(OCH3)2C6H3]2Ni (compound II). Pour ethylene through the autoclave until saturation, and simultaneously maintain the temperature in a 60 °C oil bath with electromagnetic stirring. After ethylene saturation, 10 mmol of methyl methacrylate and 13 mL of methylaluminoxane (1.53 M) were added. Ethylene was continued to be introduced while maintaining the ethylene pressure at 2 MPa. After reacting for 3 hours, the ethylene supply was stopped, the pressure was released, and the mixture was treated with a 5% hydrochloric acid-ethanol solution. After washing, filtration, and drying, 50.4 g of the copolymer was obtained, with a catalytic activity of 4.2 × 10⁻⁶. 5 gPolymer / molNi·h, the weight-average molecular weight of the copolymer is 22×10⁻⁶. 4 g / mol, with a methyl methacrylate insertion rate of 17.5 mol%.

[0062] Example 5

[0063] This embodiment provides a method for copolymerizing ethylene with methyl methacrylate, comprising the following steps:

[0064] In a clean, dry 250 mL autoclave, under an ethylene atmosphere, add 100 mL of toluene, followed by 20.0 μmol of catalyst [2,6-(C2H5)2-4-OCH3-C6H3-N=C(CH3)-C(CH3)=N-2,6-(C2H5)2-4-OCH3-C6H3]NiBr2 (compound I) and 20.0 μmol of catalyst [O-C6H4-oC(H)=N-2,6-(OCH3)2C6H3]2Ni (compound II). Pour ethylene through the autoclave until saturation, and simultaneously maintain the temperature in a 60 °C oil bath with electromagnetic stirring. After ethylene saturation, 10 mmol of methyl methacrylate and 13 mL of MAO (1.53 M) were added. Ethylene was continued to be introduced while maintaining the ethylene pressure at 2 MPa. After reacting for 3 hours, the ethylene supply was stopped, the pressure was released, and the mixture was treated with a 5% hydrochloric acid-ethanol solution. After washing, filtration, and drying, 94.8 g of the copolymer was obtained, with a catalytic activity of 7.9 × 10⁻⁶. 5 The copolymer has a weight-average molecular weight of 51.7 × 10⁻⁶ gPolymer / molNi·h. 4 g / mol, with a methyl methacrylate insertion rate of 16.5 mol%.

[0065] Example 6

[0066] This embodiment provides a method for copolymerizing ethylene with methyl methacrylate, comprising the following steps:

[0067] In a clean, dry 250 mL autoclave, under an ethylene atmosphere, add 100 mL of toluene, followed by 20.0 μmol of catalyst [2,6-(C2H5)2-4-OCH3-C6H3-N=C(CH3)-C(CH3)=N-2,6-(C2H5)2-4-OCH3-C6H3]NiBr2 (compound I) and 20.0 μmol of catalyst [O-C6H4-oC(H)=N-2,6-(OCH3)2C6H3]2Ni (compound II). Pour ethylene through the autoclave until saturation, and simultaneously maintain the temperature in a 30°C oil bath with electromagnetic stirring. After ethylene saturation, 10 mmol of methyl methacrylate and 13 mL of sesquiethylaluminum (1.53 M) were added. Ethylene was continued to be introduced while maintaining the ethylene pressure at 10 MPa. After reacting for 2 hours, the ethylene supply was stopped, the pressure was released, and the mixture was treated with a 5% hydrochloric acid-ethanol solution. After washing, filtration, and drying, 64.8 g of the copolymer was obtained, with a catalytic activity of 8.1 × 10⁻⁶. 5 The copolymer has a weight-average molecular weight of 23.0 × 10⁻⁶ gPolymer / molNi·h. 4g / mol, with a methyl methacrylate insertion rate of 1.5 mol%.

[0068] Example 7

[0069] This embodiment provides a method for copolymerizing ethylene with methyl methacrylate, comprising the following steps:

[0070] In a clean, dry 250 mL autoclave, under an ethylene atmosphere, add 100 mL of toluene, followed by 20.0 μmol of catalyst [2,6-(C2H5)2-4-OCH3-C6H3-N=C(CH3)-C(CH3)=N-2,6-(C2H5)2-4-OCH3-C6H3]NiBr2 (compound I) and 20.0 μmol of catalyst [O-C6H4-oC(H)=N-2,6-(OCH3)2C6H3]2Ni (compound II). Pour ethylene through the autoclave until saturation, and simultaneously maintain the temperature in an 80 °C oil bath with electromagnetic stirring. After ethylene saturation, 10 mmol of methyl methacrylate and 26 mL of diethylaluminum chloride (1.53 M) were added. Ethylene was continued to be introduced while maintaining the ethylene pressure at 5 MPa. After reacting for 1 hour, the ethylene supply was stopped, the pressure was released, and the mixture was treated with a 5% hydrochloric acid-ethanol solution. After washing, filtration, and drying, 4.4 g of the copolymer was obtained, with a catalytic activity of 1.1 × 10⁻⁶. 5 The copolymer has a weight-average molecular weight of 11.7 × 10⁻⁶ gPolymer / molNi·h. 4 g / mol, with a methyl methacrylate insertion rate of 9.5 mol%.

[0071] Example 8

[0072] This embodiment provides a method for copolymerizing ethylene with methyl methacrylate, comprising the following steps:

[0073] In a clean and dry 250 mL autoclave, under an ethylene atmosphere, add 100 mL of dichloroethane, 20.0 μmol of [2,6-(C2H5)2-4-OCH3-C6H3-N=C(CH3)-C(CH3)=N-2,6-(C2H5)2-4-OCH3-C6H3]NiBr2 (compound I), and 20.0 μmol of [O-C6H4-oC(H)=N-2,6-(OCH3)2C6H3]2Ni (compound II). Purge with ethylene until saturated, and simultaneously place the autoclave in a 45 °C oil bath for constant temperature and start electromagnetic stirring. After ethylene saturation, 10 mmol of methyl methacrylate and 7.8 mL (1.53 M) of sesquiethylaluminum were added. Ethylene was continued to be introduced while maintaining the ethylene pressure at 3 MPa. After reacting for 2 hours, the ethylene supply was stopped, the pressure was released, and the mixture was treated with a 5% hydrochloric acid-ethanol solution. After washing, filtration, and drying, 40.0 g of the copolymer was obtained, with a catalytic activity of 5.0 × 10⁻⁶. 5The copolymer has a weight-average molecular weight of 10.9 × 10⁻⁶ gPolymer / molNi·h. 4 g / mol, with a methyl methacrylate insertion rate of 16.3 mol%.

[0074] Example 9

[0075] This embodiment provides a method for copolymerizing ethylene with methyl methacrylate, comprising the following steps:

[0076] In a clean, dry 250 mL autoclave, under an ethylene atmosphere, add 100 mL of toluene, 20.0 μmol of [2,6-(C2H5)2-4-OCH3-C6H3-N=C(CH3)-C(CH3)=N-2,6-(C2H5)2-4-OCH3-C6H3]NiBr2 (compound I), and 0.25 μmol of [O-C6H4-oC(H)=N-2,6-(OCH3)2C6H3]2Ni (compound II). The molar ratio of catalyst I to catalyst II is 80:1. Purge with ethylene until saturated, and simultaneously maintain the temperature in a 60 °C oil bath with electromagnetic stirring. After ethylene saturation, 10 mmol of methyl methacrylate and 7.8 mL of MAO (1.53 M) were added. Ethylene was continued to be introduced while maintaining the ethylene pressure at 2 MPa. After reacting for 3 hours, the ethylene supply was stopped, the pressure was released, and the mixture was treated with a 5% hydrochloric acid-ethanol solution. After washing, filtration, and drying, 9.36 g of the copolymer was obtained, with a catalytic activity of 0.78 × 10⁻⁶. 5 The copolymer has a weight-average molecular weight of 15.2 × 10⁻⁶ gPolymer / molNi·h. 4 g / mol, with a methyl methacrylate insertion rate of 1.5 mol%.

[0077] Example 10

[0078] This embodiment provides a method for copolymerizing ethylene with methyl methacrylate, comprising the following steps:

[0079] In a clean, dry 250 mL autoclave, under an ethylene atmosphere, add 100 mL of toluene, 0.2 μmol of [2,6-(C2H5)2-4-OCH3-C6H3-N=C(CH3)-C(CH3)=N-2,6-(C2H5)2-4-OCH3-C6H3]NiBr2 (compound I), and 20.0 μmol of [O-C6H4-oC(H)=N-2,6-(OCH3)2C6H3]2Ni (compound II), with a molar ratio of catalyst I to catalyst II of 1:100. Purge with ethylene until saturated, and simultaneously maintain the temperature in a 60 °C oil bath while starting a magnetic stirrer. After ethylene saturation, 10 mmol of methyl methacrylate and 7.8 mL of MAO (1.53 M) were added. Ethylene was continued to be introduced while maintaining the ethylene pressure at 2 MPa. After reacting for 3 hours, the ethylene supply was stopped, the pressure was released, and the mixture was treated with a 5% hydrochloric acid-ethanol solution. After washing, filtration, and drying, 5.88 g of the copolymer was obtained, with a catalytic activity of 0.49 × 10⁻⁶. 5 gPolymer / molNi·h, the weight-average molecular weight of the copolymer is 8.5×10 4 g / mol, with a methyl methacrylate insertion rate of 18.7 mol%.

[0080] Example 11

[0081] This embodiment provides a method for copolymerizing ethylene with methyl methacrylate, comprising the following steps:

[0082] In a clean, dry 250 mL autoclave, under an ethylene atmosphere, 100 mL of toluene was added, along with 39.2 μmol of catalyst [2,6-(CH3)2-4-N(CH3)2-C6H3-N=C(H)-C(C2H5)=N-2,6-(CH3)2-4-N(CH3)2-C6H3]PdCl2 (compound III) and 0.8 μmol of [O-(3-(CH3)C6H3-oC(H)=N-2,6-(OH)2C6H3]2Ni (compound IV). Ethylene was then introduced until saturation, and the autoclave was kept at a constant temperature of 60 °C in an oil bath with electromagnetic stirring. After ethylene saturation, 50 mmol of methyl methacrylate was added, followed by MAO. 13 mL (1.53 M) of ethylene was continuously introduced, maintaining an ethylene pressure of 2 MPa. After 2 hours of reaction, the ethylene supply was stopped. The pressure was released, and the mixture was treated with a 5% hydrochloric acid-ethanol solution. After washing, filtration, and drying, 12.0 g of the copolymer was obtained, with a catalytic activity of 3.0 × 10⁻⁶. 5 The copolymer has a weight-average molecular weight of 52.5 × 10 gPolymer / molM·h. 4 g / mol, with a methyl methacrylate insertion rate of 12.1 mol%.

[0083] Example 12

[0084] This embodiment provides a method for copolymerizing ethylene with methyl methacrylate, comprising the following steps:

[0085] In a clean, dry 250 mL autoclave, under an ethylene atmosphere, 100 mL of toluene was added, along with 0.8 μmol of catalyst [2,6-(CH3)2-4-N(CH3)2-C6H3-N=C(H)-C(C2H5)=N-2,6-(CH3)2-4-N(CH3)2-C6H3]PdCl2 (compound III) and 39.2 μmol of [O-(3-(CH3)C6H3-oC(H)=N-2,6-(OH)2C6H3]2Ni (compound IV). Ethylene was bubbled through until saturation, and the autoclave was kept at a constant temperature of 60 °C in an oil bath with electromagnetic stirring. After ethylene saturation, 50 mmol of methyl methacrylate was added, followed by MAO. 13 mL (1.53 M) of ethylene was continuously introduced, maintaining an ethylene pressure of 2 MPa. After reacting for 2 hours, the ethylene supply was stopped. The pressure was released, and the mixture was treated with a 5% hydrochloric acid-ethanol solution. After washing, filtration, and drying, 6.0 g of the copolymer was obtained, with a catalytic activity of 1.5 × 10⁻⁶. 5 The copolymer has a weight-average molecular weight of 10.1 × 10⁻⁶ gPolymer / mol M·h. 4 g / mol, with a methyl methacrylate insertion rate of 42 mol%.

[0086] Example 13

[0087] This embodiment provides a method for copolymerizing ethylene with methyl methacrylate, comprising the following steps:

[0088] In a clean, dry 250 mL autoclave, 100 mL of a mixed solution of dichloromethane and toluene (volume ratio 5:5) was added under an ethylene atmosphere. Then, 36.36 μmol of catalyst [2,6-(CH3)2-4-N(CH3)2-C6H3-N=C(H)-C(C2H5)=N-2,6-(CH3)2-4-N(CH3)2-C6H3]PdCl2 (compound III) and 3.64 μmol of catalyst [O-(3-(CH3)C6H3-oC(H)=N-2,6-(OH)2C6H3]2Ni (compound IV) were added. Ethylene was bubbled through until saturation, and the autoclave was kept at a constant temperature of 60 °C in an oil bath with electromagnetic stirring. After ethylene saturation, 50 mmol of methyl methacrylate and MAO were added. 13 mL (1.53 M) of ethylene was continuously introduced, maintaining an ethylene pressure of 5 MPa. After reacting for 1 hour, the ethylene supply was stopped. The pressure was released, and the mixture was treated with a 5% hydrochloric acid-ethanol solution. After washing, filtration, and drying, 16.0 g of the copolymer was obtained, with a catalytic activity of 4.0 × 10⁻⁶. 5The copolymer has a weight-average molecular weight of 49.8 × 10 gPolymer / molM·h. 4 g / mol, with a methyl methacrylate insertion rate of 17.2 mol%.

[0089] Example 14

[0090] This embodiment provides a method for copolymerizing ethylene with methyl methacrylate, comprising the following steps:

[0091] In a clean, dry 250 mL autoclave, 100 mL of a mixed solution of dichloromethane and toluene (volume ratio of dichloromethane to toluene = 3:7) was added under an ethylene atmosphere. 3.64 μmol of catalyst [2,6-(CH3)2-4-N(CH3)2-C6H3-N=C(H)-C(C2H5)=N-2,6-(CH3)2-4-N(CH3)2-C6H3]PdCl2 and 36.36 μmol of catalyst [O-(3-(CH3)C6H3-oC(H)=N-2,6-(OH)2C6H3]2Ni were added. Ethylene was bubbled through until saturation, and the autoclave was kept at a constant temperature of 60 °C in an oil bath with electromagnetic stirring. After ethylene saturation, 50 mmol of methyl methacrylate and MAO were added. 13 mL (1.53 M) of ethylene was continuously introduced, maintaining an ethylene pressure of 5 MPa. After reacting for 1 hour, the ethylene supply was stopped. The pressure was released, and the mixture was treated with a 5% hydrochloric acid-ethanol solution. After washing, filtration, and drying, 8.8 g of the copolymer was obtained, with a catalytic activity of 2.2 × 10⁻⁶. 5 gPolymer / molM·h, the weight-average molecular weight of the copolymer is 10.8 × 10⁻⁶ gPolymer / molM·h. 4 g / mol, with a methyl methacrylate insertion rate of 33.4 mol%.

[0092] Example 15

[0093] This embodiment provides a method for copolymerizing ethylene with methyl methacrylate, comprising the following steps:

[0094] In a clean, dry 250 mL autoclave, 100 mL of a mixed solution of dichloroethane and n-hexane (volume ratio 5:5) was added under an ethylene atmosphere. 20.0 μmol of catalyst [2,6-(CH3)2-4-N(CH3)2-C6H3-N=C(H)-C(C2H5)=N-2,6-(CH3)2-4-N(CH3)2-C6H3]PdCl2 (compound III) and 20.0 μmol of catalyst [O-(3-(CH3)C6H3-oC(H)=N-2,6-(OH)2C6H3]2Ni (compound IV) were added. Ethylene was bubbled through until saturation, and the autoclave was kept at a constant temperature of 60 °C in an oil bath with electromagnetic stirring. After ethylene saturation, 50 mmol of methyl methacrylate and MAO were added. 7.8 mL (1.53 M) of ethylene was continuously introduced, maintaining an ethylene pressure of 5 MPa. After reacting for 1 hour, the ethylene supply was stopped. The pressure was released, and the mixture was treated with a 5% hydrochloric acid-ethanol solution. After washing, filtration, and drying, 14.0 g of the copolymer was obtained, with a catalytic activity of 3.5 × 10⁻⁶. 5 The copolymer has a weight-average molecular weight of 21.6 × 10⁻⁶ gPolymer / mol M·h. 4 g / mol, with a methyl methacrylate insertion rate of 24.4 mol%.

[0095] Example 16

[0096] This embodiment provides a method for copolymerizing ethylene with methyl methacrylate, comprising the following steps:

[0097] In a clean, dry 250 mL autoclave, 100 mL of a mixed solution of dichloromethane and toluene (volume ratio 5:5) was added under an ethylene atmosphere. 20.0 μmol of catalyst [2,6-(CH3)2-4-N(CH3)2-C6H3-N=C(H)-C(C2H5)=N-2,6-(CH3)2-4-N(CH3)2-C6H3]PdCl2 (compound III) and 20.0 μmol of catalyst [O-(3-(CH3)C6H3-oC(H)=N-2,6-(OH)2C6H3]2Ni (compound IV) were added. Ethylene was bubbled through until saturation, and the autoclave was kept at a constant temperature of 30 °C in an oil bath with electromagnetic stirring. After ethylene saturation, 50 mmol of methyl methacrylate and MAO were added. 7.8 mL (1.53 M) of ethylene was continuously introduced, maintaining the ethylene pressure at 10 MPa. After reacting for 2 hours, the ethylene supply was stopped. The pressure was released, and the mixture was treated with a 5% hydrochloric acid-ethanol solution. After washing, filtration, and drying, 20 g of the copolymer was obtained, with a catalytic activity of 5.0 × 10⁻⁶. 5 The copolymer has a weight-average molecular weight of 19.1 × 10⁻⁶ gPolymer / mol M·h. 4 g / mol, with a methyl methacrylate insertion rate of 12.3 mol%.

[0098] Example 17

[0099] This embodiment provides a method for copolymerizing ethylene with methyl methacrylate, comprising the following steps:

[0100] In a clean, dry 250 mL autoclave, under an ethylene atmosphere, 100 mL of toluene was added, along with 20.0 μmol of catalyst [2,6-(CH3)2-4-N(CH3)2-C6H3-N=C(H)-C(C2H5)=N-2,6-(CH3)2-4-N(CH3)2-C6H3]PdCl2 (compound III) and [O-(3-(CH3)C6H3-oC(H)=N-2,6-(OH)2C6H3]2N Compound IV (20.0 μmol) was introduced into a solution of ethylene and kept at an 80°C oil bath with a magnetic stirrer. After ethylene saturation, 50 mmol of methyl methacrylate and 7.8 mL (1.53 M) of sesquiethylaluminum were added. Ethylene was continued to be introduced while maintaining a pressure of 2 MPa. The reaction was allowed to proceed for 2 hours, after which the ethylene supply was stopped. The mixture was then depressurized, treated with a 5% hydrochloric acid-ethanol solution, washed, filtered, and dried to obtain 18.4 g of the copolymer, exhibiting a catalytic activity of 2.3 × 10⁻⁶. 5 The copolymer has a weight-average molecular weight of 16.7 × 10 gPolymer / molM·h. 4 g / mol, with a methyl methacrylate insertion rate of 27.9 mol%.

[0101] Example 18

[0102] This embodiment provides a method for copolymerizing ethylene with methyl methacrylate, comprising the following steps:

[0103] In a clean, dry 250 mL autoclave, under an ethylene atmosphere, 100 mL of toluene was added, along with 20.0 μmol of catalyst [2,6-(CH3)2-4-N(CH3)2-C6H3-N=C(H)-C(C2H5)=N-2,6-(CH3)2-4-N(CH3)2-C6H3]PdCl2 (compound III) and [O-(3-(CH3)C6H3-oC(H)=N-2,6-(OH)2C6H3]2Ni (Compound IV) 20.0 μmol was introduced into an oil bath at 60 °C with ethylene until saturation, and the mixture was kept at a constant temperature with electromagnetic stirring. After ethylene saturation, 50 mmol of methyl methacrylate was added, followed by 1.53 M, 7.8 mL of diethylaluminum aluminum. Ethylene was continued to be introduced while maintaining the ethylene pressure at 3 MPa. After 3 hours of reaction, the ethylene supply was stopped. The pressure was released, and the mixture was treated with a 5% hydrochloric acid-ethanol solution. After washing, filtration, and drying, 32.4 g of the copolymer was obtained, with a catalytic activity of 2.7 × 10⁻⁶.5 The copolymer has a weight-average molecular weight of 22.1 × 10⁻⁶ gPolymer / mol M·h and a weight-average molecular weight of 22.1 × 10⁻⁶ gPolymer / mol M·h. 4 g / mol, with a methyl methacrylate insertion rate of 24.5 mol%.

[0104] Example 19

[0105] This embodiment provides a method for copolymerizing ethylene with methyl methacrylate, comprising the following steps:

[0106] In a clean, dry 250 mL autoclave, 100 mL of a mixed solution of dichloromethane and toluene (volume ratio 5:5) was added under an ethylene atmosphere. 40.0 μmol of catalyst [2,6-(CH3)2-4-N(CH3)2-C6H3-N=C(H)-C(C2H5)=N-2,6-(CH3)2-4-N(CH3)2-C6H3]PdCl2 (compound III) and 0.4 μmol of [O-(3-(CH3)C6H3-oC(H)=N-2,6-(OH)2C6H3]2Ni (compound IV) were added, with a molar ratio of catalyst I to catalyst II of 100:1. Ethylene was introduced until saturation, and the autoclave was kept at a constant temperature of 60 °C in an oil bath with electromagnetic stirring. After ethylene saturation, 50 mmol of methyl methacrylate and MAO were added. 7.8 mL (1.53 M) of ethylene was continuously introduced, maintaining an ethylene pressure of 5 MPa. After reacting for 1 hour, the ethylene supply was stopped. The pressure was released, and the mixture was treated with a 5% hydrochloric acid-ethanol solution. After washing, filtration, and drying, 8.4 g of the copolymer was obtained, exhibiting a catalytic activity of 2.1 × 10⁻⁶. 5 The copolymer has a weight-average molecular weight of 21.1 × 10⁻⁶ gPolymer / mol M·h and a weight-average molecular weight of 21.1 × 10⁻⁶ gPolymer / mol M·h. 4 g / mol, with a methyl methacrylate insertion rate of 4.6%.

[0107] Example 20

[0108] This embodiment provides a method for copolymerizing ethylene with methyl methacrylate, comprising the following steps:

[0109] In a clean, dry 250 mL autoclave, 100 mL of a mixed solution of dichloromethane and toluene (volume ratio 5:5) was added under an ethylene atmosphere. 0.4 μmol of catalyst [2,6-(CH3)2-4-N(CH3)2-C6H3-N=C(H)-C(C2H5)=N-2,6-(CH3)2-4-N(CH3)2-C6H3]PdCl2 (compound III) and 40.0 μmol of [O-(3-(CH3)C6H3-oC(H)=N-2,6-(OH)2C6H3]2Ni (compound IV) were added, with a molar ratio of catalyst I to catalyst II of 1:100. Ethylene was introduced until saturation, and the autoclave was kept at a constant temperature of 60 °C in an oil bath with electromagnetic stirring. After ethylene saturation, 50 mmol of methyl methacrylate and MAO were added. 7.8 mL (1.53 M) of ethylene was continuously introduced, maintaining an ethylene pressure of 5 MPa. After reacting for 1 hour, the ethylene supply was stopped. The pressure was released, and the mixture was treated with a 5% hydrochloric acid-ethanol solution. After washing, filtration, and drying, 3.2 g of the copolymer was obtained, with a catalytic activity of 0.8 × 10⁻⁶. 5 The copolymer has a weight-average molecular weight of 11.6 × 10⁻⁶ gPolymer / mol M·h. 4 g / mol, with a methyl methacrylate insertion rate of 31.7 mol%.

[0110] Example 21

[0111] This embodiment provides a method for copolymerizing ethylene and methyl acrylate, comprising the following steps:

[0112] In a clean, dry 250 mL autoclave, under an ethylene atmosphere, add 100 mL of toluene, 20.0 μmol of catalyst [2,6-(CH3)2-4-N(CH3)2-C6H3-N=C(H)-C(C2H5)=N-2,6-(CH3)2-4-N(CH3)2-C6H3]PdCl2 (compound III), and 20.0 μmol of [O-(3-(CH3)C6H3-oC(H)=N-2,6-(OH)2C6H3]2Ni (compound IV). Purge with ethylene until saturated, and simultaneously maintain the temperature in a 60 °C oil bath with electromagnetic stirring. After ethylene saturation, add 10 mmol of methyl acrylate and MAO. 13 mL (1.53 M) of ethylene was continuously introduced, maintaining an ethylene pressure of 5 MPa. After reacting for 1 hour, the ethylene supply was stopped. The pressure was released, and the mixture was treated with a 5% hydrochloric acid-ethanol solution. After washing, filtration, and drying, 4.4 g of the copolymer was obtained, with a catalytic activity of 1.1 × 10⁻⁶. 5 The copolymer has a weight-average molecular weight of 11.2 × 10⁻⁶ gPolymer / mol M·h. 4 g / mol, the insertion rate of methyl acrylate is 3.5 mol%.

[0113] Example 22

[0114] This embodiment provides a method for copolymerizing ethylene and ethyl acrylate, comprising the following steps:

[0115] In a clean, dry 250 mL autoclave, under an ethylene atmosphere, add 100 mL of toluene, 20.0 μmol of catalyst [2,6-(CH3)2-4-N(CH3)2-C6H3-N=C(H)-C(C2H5)=N-2,6-(CH3)2-4-N(CH3)2-C6H3]PdCl2 (compound III), and 20.0 μmol of [O-(3-(CH3)C6H3-oC(H)=N-2,6-(OH)2C6H3]2Ni (compound IV). Purge with ethylene until saturated, and simultaneously maintain the temperature in a 60 °C oil bath with electromagnetic stirring. After ethylene saturation, add 10 mmol of ethyl acrylate and MAO. 13 mL (1.53 M) of ethylene was continuously introduced, maintaining an ethylene pressure of 5 MPa. After reacting for 1 hour, the ethylene supply was stopped. The pressure was released, and the mixture was treated with a 5% hydrochloric acid-ethanol solution. After washing, filtration, and drying, 4.0 g of the copolymer was obtained, with a catalytic activity of 1.0 × 10⁻⁶. 5 The copolymer has a weight-average molecular weight of 10.7 × 10 gPolymer / molM·h. 4 g / mol, the insertion rate of ethyl acrylate is 2.7 mol%.

[0116] Example 23

[0117] This embodiment provides a method for copolymerizing ethylene with butyl acrylate, comprising the following steps:

[0118] In a clean, dry 250 mL autoclave, under an ethylene atmosphere, add 100 mL of toluene, 20.0 μmol of catalyst [2,6-(CH3)2-4-N(CH3)2-C6H3-N=C(H)-C(C2H5)=N-2,6-(CH3)2-4-N(CH3)2-C6H3]PdCl2 (compound III), and 20.0 μmol of [O-(3-(CH3)C6H3-oC(H)=N-2,6-(OH)2C6H3]2Ni (compound IV). Purge with ethylene until saturated, and simultaneously maintain the temperature in a 60 °C oil bath with electromagnetic stirring. After ethylene saturation, add 10 mmol of butyl acrylate and MAO. 13 mL (1.53 M) of ethylene was continuously introduced, maintaining an ethylene pressure of 5 MPa. After reacting for 1 hour, the ethylene supply was stopped. The pressure was released, and the mixture was treated with a 5% hydrochloric acid-ethanol solution. After washing, filtration, and drying, 4.2 g of the copolymer was obtained, with a catalytic activity of 1.05 × 10⁻⁶. 5The copolymer has a weight-average molecular weight of 10.1 × 10⁻⁶ gPolymer / mol M·h. 4 g / mol, with an insertion rate of butyl acrylate of 1.6 mol%.

[0119] The reaction conditions of the above embodiments are shown in Table 1, and the copolymerization results are shown in Table 2.

[0120] Table 1 Reaction conditions for the examples and comparative examples

[0121]

[0122]

[0123] Table 2. Results of ethylene-acrylate copolymerization in the examples and comparative examples.

[0124]

[0125] In the comparative examples of this invention, the catalyst used is compound V or compound VI, with the following structure.

[0126]

[0127] Comparative Example 1

[0128] This comparative example provides a method for copolymerizing ethylene with methyl methacrylate, comprising the following steps:

[0129] In a clean, dry 250 mL autoclave, under an ethylene atmosphere, 100 mL of toluene, 40.0 μmol of [2,6-(CH3)2C6H3-N=C(H)-C(H)=N-2,6-(CH3)2C6H3]NiBr2 (compound V), 50 mmol of methyl methacrylate, and 13 mL (1.53 M) of MAO were added. Ethylene was introduced until saturation, and the autoclave was kept at 60 °C in an oil bath with a magnetic stirrer running. The ethylene pressure was maintained at 5 MPa, and the reaction was stopped after 3 hours. The pressure was released, and the autoclave was treated with a 5% hydrochloric acid-ethanol solution, washed, filtered, and dried. The catalytic activity was 1 × 10⁻⁶. 4 The copolymer has a weight-average molecular weight of 1.02 × 10⁻⁶ gPolymer / molNi·h. 4 g / mol, with a methyl methacrylate insertion rate of 1.2 mol%.

[0130] Comparative Example 2

[0131] This comparative example provides a method for copolymerizing ethylene with methyl methacrylate, comprising the following steps:

[0132] In a clean, dry 250 mL autoclave, 100 mL of toluene was added under an ethylene atmosphere. The autoclave was placed in a 60 °C oil bath and kept at a constant temperature with electromagnetic stirring. 39.21 μmol of [O-(3-(i-C3H7)C6H3-oC(H)=N-2,6-(i-C3H7)2C6H3]2Ni (compound VI) was added, along with 50 mmol of methyl methacrylate and 13 mL (1.53 M) of MAO. Ethylene was continuously introduced until saturation, maintaining an ethylene pressure of 5 MPa. After reacting for 3 hours, the ethylene supply was stopped. The pressure was released, and the mixture was treated with a 5% hydrochloric acid-ethanol solution, washed, filtered, and dried. The catalytic activity was 2 × 10⁻⁶. 4 The copolymer has a weight-average molecular weight of 1.54 × 10⁻⁶ gPolymer / molNi·h. 4 g / mol, with a methyl methacrylate insertion rate of 5.4 mol%.

[0133] The reaction conditions for the comparative examples are shown in Table 1, and the copolymerization results are shown in Table 2. The comparative examples showed low catalytic activity and the resulting copolymers had lower molecular weights.

Claims

1. A composite catalyst, characterized in that, It includes a main catalyst and a co-catalyst, wherein the main catalyst comprises an α-diimine post-transition metal complex and a bis-salicylaldehyde imine post-transition metal complex in a molar ratio of 1:10-10:1; The α-diimine post-transition metal complex is selected from one or more compounds having the general formula shown in formula (I). Formula (I) In formula (I), R1 and R2 are the same or different aryl groups, with a first substituent attached to the ortho position of the C bonded to N on the aryl group and a second substituent attached to the para position of the C bonded to N. The first substituent is selected from hydrogen, C1-C2 alkyl, C1-C2 alkoxy, or hydroxyl, and the second substituent is selected from C1-C2 alkyl, alkylamino, alkoxy, amino, or hydroxyl. R3 and R4 are the same or different, and each of R3 and R4 is independently selected from hydrogen or C1-C4 alkyl. M1 is selected from Ni or Pd. X1 and X2 are the same or different, and each of X1 and X2 is independently selected from halogen, C2-C4 ether, or C1-C4 nitrile. The bis-salicylaldehyde imine post-transition metal complex is selected from one or more compounds having the general formula shown in formula (II). Equation (II) In formula (II), R5 and R6 may be the same or different, and each of R5 and R6 is independently selected from hydrogen, C1-C2 alkyl, C1-C2 alkoxy or hydroxyl; R7 and R8 may be the same or different, and each of R7 and R8 is independently selected from hydrogen, C1-C6 alkyl, C1-C6 alkoxy, hydroxyl or aryl; M2 is selected from Ni or Pd.

2. The composite catalyst according to claim 1, characterized in that, In formula (I), the first substituent is selected from hydrogen, methyl or ethyl; the second substituent is selected from C1-C2 alkyl, C1-C2 alkoxy or amino.

3. The composite catalyst according to claim 1, characterized in that, In formula (I), R3 and R4 are each independently selected from hydrogen and C1-C2 alkyl groups.

4. The composite catalyst according to claim 1, characterized in that, In equation (I), M1 is Ni.

5. The composite catalyst according to claim 1, characterized in that, In formula (II), R7 and R8 are each independently selected from hydrogen, C1-C2 alkyl, and C1-C2 alkoxy.

6. The composite catalyst according to claim 1, characterized in that, In equation (II), M2 is Ni.

7. The composite catalyst according to claim 1, characterized in that, The cocatalyst includes an organoaluminum compound selected from methylaluminoxane, alkylaluminum, and sesquialkylaluminum.

8. The composite catalyst according to claim 7, characterized in that, The organoaluminum compound is selected from sesquiethylaluminum, triethylaluminum, and methylaluminoxane.

9. The composite catalyst according to claim 7, characterized in that, The molar ratio of aluminum in the co-catalyst to the total metal content in the main catalyst is 50-1000:

1.

10. The composite catalyst according to claim 7, characterized in that, The molar ratio of aluminum in the co-catalyst to the total metal content in the main catalyst is 100-500:

1.

11. The use of the composite catalyst according to any one of claims 1-10 in the copolymerization of ethylene and acrylates.

12. The application according to claim 11, characterized in that, The acrylate is methyl methacrylate.

13. A method for copolymerizing ethylene with methyl methacrylate, characterized in that, Includes the following steps: In an ethylene atmosphere, methyl methacrylate and the composite catalyst described in any one of claims 1-10 are brought into full contact in an organic solvent to carry out a copolymerization reaction of ethylene and methyl methacrylate. After terminating the reaction, a copolymer is obtained.

14. The copolymerization method according to claim 13, characterized in that, The copolymerization reaction pressure is 0.05-10 MPa.

15. The copolymerization method according to claim 13, characterized in that, The copolymerization reaction pressure is 0.8-5 MPa.

16. The copolymerization method according to claim 13, characterized in that, The copolymerization reaction temperature is 0-80℃.

17. The copolymerization method according to claim 13, characterized in that, The copolymerization reaction temperature is 30-60℃.

18. The copolymerization method according to claim 13, characterized in that, The copolymerization reaction time is 0.1-24 h.

19. The copolymerization method according to claim 13, characterized in that, The copolymerization reaction time is 0.5-12 hours.

20. The copolymerization method according to claim 13, characterized in that, The concentration of methyl methacrylate in the reaction system is 0.01-6.0M.

21. The copolymerization method according to claim 13, characterized in that, The concentration of methyl methacrylate in the reaction system is 0.1-5.0 M.

22. The copolymerization method according to claim 13, characterized in that, The terminating agent used to terminate the reaction was hydrochloric acid ethanol solution.

23. The copolymerization method according to claim 13, characterized in that, The organic solvent is selected from one or more of toluene, n-hexane, cyclohexane, dichloromethane, dichloroethane, and chlorobenzene.

Images