A catalyst for copolymerization of ethylene and methyl methacrylate and use thereof

Abstract

The application provides a catalyst for ethylene and methyl methacrylate copolymerization and application thereof, which comprises a main catalyst, wherein the main catalyst is obtained by compounding a compound of formula (I) and a compound of formula (II); the molar ratio of the compound of formula (I) to the compound of formula (II) is (1:49) to (49:1). The catalyst has excellent catalytic activity, and can obtain a high molecular weight ethylene and methyl methacrylate copolymer with a weight average molecular weight not less than 1x10 5 g / mol.

Description

Technical Field

[0001] This invention belongs to the field of olefin polymerization and relates to a catalyst for the copolymerization of ethylene and methyl methacrylate and its application. Background Technology

[0002] Compared to traditional polyethylene, functional polyethylene copolymerized from ethylene and polar methacrylate monomers exhibits better compatibility, adhesion, dyeability, and printability. However, the coordination copolymerization of ethylene and methyl methacrylate (MMA) presents a technical challenge. This is primarily because MMA has greater steric hindrance compared to other polar acrylate monomers, resulting in lower copolymerization activity and lower molecular weight of the copolymer when interacting with active centers. Furthermore, controlling the insertion rate of MMA in the copolymer is difficult. Existing ethylene-methyl methacrylate copolymerization technologies mainly utilize a post-transition metal catalyst. Under conditions where the molar ratio of co-catalyst aluminoxane to main catalyst is ≤1000:1, copolymerization of ethylene and methacrylate can be achieved, but the resulting copolymer has a low molecular weight, typically only 1×10⁻⁶. 4 g / mol.

[0003] Therefore, how to synthesize a high molecular weight ethylene-methacrylate copolymer is an urgent problem to be solved in this field. Summary of the Invention

[0004] This invention provides a catalyst for the copolymerization of ethylene and methyl methacrylate. The catalyst is produced by compounding a compound of formula (I) having an α-diimine post-transition metal complex structure and a compound of formula (II) having a bis-salicylaldehyde imine post-transition metal complex in a specific molar ratio. This catalyst is used to catalyze the copolymerization reaction of methyl methacrylate and ethylene, yielding a product with a molecular weight not less than 1 × 10⁻⁶. 5 A copolymer of ethylene and methyl methacrylate at g / mol.

[0005] This invention also provides a method for copolymerizing ethylene and methyl methacrylate, which can yield a product with a molecular weight of not less than 1×10⁻⁶. 5 This method produces a copolymer of high molecular weight ethylene and methyl methacrylate at g / mol. Furthermore, it can complete the copolymerization of ethylene and methyl methacrylate in a shorter time at lower reaction temperatures and pressures, offering the advantages of being mild and efficient.

[0006] The present invention also provides a copolymer of ethylene and methyl methacrylate, which has the advantages of high molecular weight and adjustable methyl methacrylate insertion rate.

[0007] This invention provides a catalyst for the copolymerization of ethylene and methyl methacrylate, the catalyst comprising a main catalyst, the main catalyst being obtained by compounding compound (I) and compound (II);

[0008] The structure of equation (I) is as follows:

[0009]

[0010] R1 and R2 are each independently selected from substituted aryl groups, and the substituents are selected from at least one of C1-C6 alkyl groups and C1-C6 alkoxy groups;

[0011] R3 and R4 are each independently selected from hydrogen and C1 to C4 alkyl groups;

[0012] M is selected from Ni or Pd;

[0013] X1 and X2 are each independently selected from halogens, C1-C4 alkyl groups, aryl groups, C2-C4 ethers, and C1-C4 nitriles;

[0014] The structure of equation (II) is as follows:

[0015]

[0016] Among them, R5 and R6 are each independently selected from hydrogen, methyl, ethyl, dimethylamino, diethylamino, amino, hydroxyl, and C1-C4 alkoxy groups;

[0017] R7 and R8 are each independently selected from at least one of hydrogen, C1-C4 alkyl, C1-C4 dialkylamino, amino, hydroxyl, and C1-C4 alkoxy.

[0018] The molar ratio of formula (I) to formula (II) is (1:49) to (49:1).

[0019] The catalyst as described above, wherein the molar ratio of the compound of formula (I) to the compound of formula (II) is (1:10) to (10:1).

[0020] The catalyst as described above further includes a co-catalyst selected from aluminum oxanes.

[0021] The catalyst as described above, wherein the co-catalyst is selected from at least one of methylaluminoxane, trialkylaluminum, and haloalkylaluminum.

[0022] In the catalyst described above, the molar ratio of the metal element in the main catalyst to the aluminum element in the co-catalyst is 1:(50-1000).

[0023] In the catalyst described above, the molar ratio of the metal element in the main catalyst to the aluminum element in the co-catalyst is 1:(100-500).

[0024] The present invention also provides a method for copolymerizing ethylene with methyl methacrylate, wherein the copolymerization reaction is carried out using the catalyst described above.

[0025] The copolymerization method described above, wherein the copolymerization method comprises: copolymerizing ethylene and methyl methacrylate under the catalysis of the catalyst;

[0026] The copolymerization reaction is carried out at a pressure of ≤10MPa and a temperature of ≤100℃.

[0027] In the copolymerization method described above, the solvent for the copolymerization reaction is selected from at least one of toluene, n-hexane, dichloromethane, and dichloroethane.

[0028] The present invention also provides a copolymer of ethylene and methyl methacrylate, wherein the copolymer is prepared by the copolymerization method described above, and the weight-average molecular weight of the copolymer is ≥1×10⁻⁶. 5 g / mol.

[0029] The catalyst for copolymerization of ethylene and methyl methacrylate of the present invention uses a compound of formula (I) having an α-diimine post-transition metal complex structure and a compound of formula (II) having a bis-salicylaldehyde imine post-transition metal complex in combination. The two compounds can synergistically promote the copolymerization of ethylene and methyl methacrylate within a specific molar ratio range, thereby obtaining a high molecular weight ethylene and methyl methacrylate copolymer.

[0030] The copolymerization method of ethylene and methyl methacrylate of the present invention can yield a product with a weight-average molecular weight of not less than 1×10⁻⁶. 5 The method yields a copolymer of ethylene and methyl methacrylate at g / mol. Furthermore, it can complete the copolymerization of ethylene and methyl methacrylate in a shorter time at lower reaction temperatures and pressures, offering advantages such as mild and efficient reaction conditions, which is beneficial for industrial applications.

[0031] The copolymer of ethylene and methyl methacrylate of the present invention has a weight-average molecular weight of not less than 1 × 10⁻⁶. 5 The advantages include adjustable g / mol methyl methacrylate insertion rate. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions in the embodiments of this invention will be clearly and completely described below in conjunction with the embodiments of this invention. Obviously, the described embodiments are only some embodiments of this invention, not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0033] The first aspect of the present invention provides a catalyst for the copolymerization of ethylene and methyl methacrylate, comprising a main catalyst, said main catalyst being obtained by compounding a compound of formula (I) and a compound of formula (II);

[0034] The structure of equation (I) is as follows:

[0035]

[0036] R1 and R2 are each independently selected from substituted aryl groups, and the substituents are selected from at least one of C1-C6 alkyl groups and C1-C6 alkoxy groups;

[0037] R3 and R4 are each independently selected from hydrogen and C1 to C4 alkyl groups;

[0038] M is selected from Ni or Pd;

[0039] X1 and X2 are each independently selected from halogens, C1-C4 alkyl groups, aryl groups, C2-C4 ethers, and C1-C4 nitriles;

[0040] The structure of equation (II) is as follows:

[0041]

[0042] Among them, R5 and R6 are each independently selected from hydrogen, methyl, ethyl, dimethylamino, diethylamino, amino, hydroxyl, and C1-C4 alkoxy groups;

[0043] R7 and R8 are each independently selected from at least one of hydrogen, C1-C4 alkyl, C1-C4 dialkylamino, amino, hydroxyl, and C1-C4 alkoxy.

[0044] The molar ratio of compound (I) to compound (II) is (1:49) to (49:1).

[0045] A substituted aryl group refers to an aryl group with a substituent attached. Specifically, the aryl group can be phenyl, naphthyl, biphenyl, etc. This invention does not limit the substitution position of the substituent on the aryl group; for example, it can be ortho- or para-position in the diimine structure. C1-C6 alkyl refers to a branched or straight-chain alkyl group having 1 to 6 carbon atoms, such as methyl, ethyl, propyl, isopropyl, tert-butyl, etc. C1-C6 alkoxy refers to a branched or straight-chain alkoxy group having 1 to 6 carbon atoms, such as methoxy, ethoxy, isopropoxy, etc. Similarly, C1-C4 alkyl refers to a straight-chain or branched alkyl group having 1 to 4 carbon atoms, and C1-C4 alkoxy refers to a straight-chain or branched alkoxy group having 1 to 4 carbon atoms. C1-C4 dialkylamino refers to a substituent in which the amino group is replaced by two C1-C4 straight-chain or straight-chain alkyl groups, such as dimethylamino, diethylamino, dipropylamino, etc. Halogens are one of the following: fluorine, chlorine, bromine, and iodine.

[0046] The inventors discovered that compound (I) and compound (II) in a molar ratio of (1:49) to (49:1) form a main catalyst capable of catalyzing the copolymerization of ethylene and methyl methacrylate to obtain a product with a molecular weight of not less than 1×10⁻⁶. 5 The copolymer of ethylene and methyl methacrylate with a molecular weight of g / mol may be due to the following reasons: Compound (I) is an α-diimine post-transition metal complex, and Compound (II) is a bis-salicylaldehyde imine post-transition metal complex. The structures of the two can match and cooperate with each other, which can ensure that the reactivity ratio of ethylene and methyl methacrylate is within a suitable range, and can maximize the advantages of the two compounds with different structures. In addition, both Compound (I) and Compound (II) have electron-donating groups attached to them, which can reduce the possibility of the metal center being attacked by the ester group on methyl methacrylate. At the same time, it increases the possibility of the C=C double bond on methyl methacrylate inserting into the empty orbital of the metal center, shortening the coordination time between the double bond and the active center, thereby obtaining a high molecular weight copolymer of ethylene and methyl methacrylate.

[0047] Furthermore, when the molar ratio of compound (I) to compound (II) is (1:10) to (10:1), the catalytic activity of the catalyst, the weight-average molecular weight of the copolymer, and the insertion rate of methyl methacrylate are all at a more balanced level.

[0048] It is understood that the catalyst of the present invention also includes a co-catalyst. Specifically, the co-catalyst of the present invention is selected from aluminoxane. Aluminoxane can alkylate the main catalyst, and can also abstract halogens or alkyl groups in the main catalyst to form cationic active centers. At the same time, it can also act as a non-coordinated balancing ion, all of which are beneficial to the increase of the molecular weight of the copolymer.

[0049] Furthermore, the co-catalyst is selected from at least one of methylaluminoxane (MAO), alkylaluminum, and haloalkylaluminum. These co-catalysts are widely available and inexpensive, and can also assist the main catalyst in further increasing the molecular weight of the obtained ethylene and methyl methacrylate.

[0050] In one specific embodiment, when the molar ratio of the metal element in the main catalyst to the aluminum element in the co-catalyst is 1:(50-1000), the catalyst exhibits superior copolymerization activity of ethylene and methyl methacrylate.

[0051] Furthermore, when the molar ratio of the metal element in the main catalyst to the aluminum element in the co-catalyst is 1:(100-500), it will be more conducive to improving the copolymerization activity of the catalyst.

[0052] The second aspect of the present invention provides a method for copolymerizing ethylene and methyl methacrylate, wherein the method uses the catalyst for copolymerizing ethylene and methyl methacrylate provided in the first aspect of the present invention as a copolymerization catalyst.

[0053] The above copolymerization method exhibits excellent copolymerization activity and can yield copolymers with a molecular weight of not less than 1×10⁻⁶. 5 The copolymer of ethylene and methyl methacrylate at g / mol is produced. Furthermore, this method allows the copolymerization reaction to be carried out at lower polymerization temperatures and lower polymerization pressures, resulting in milder conditions that are beneficial for industrial applications.

[0054] The above copolymerization method can also control the insertion rate of methyl methacrylate in the copolymer by controlling factors such as copolymerization pressure, the molar ratio of raw materials to catalyst, copolymerization temperature, and copolymerization time. In specific production processes, the insertion rate of methyl methacrylate in the copolymer can be adjusted accordingly based on the ester content requirements of different products.

[0055] In one specific embodiment, the copolymerization method described above includes: copolymerizing ethylene and methyl methacrylate under the catalysis of a catalyst, wherein the copolymerization reaction pressure is ≤10 MPa and the temperature is ≤100°C. The copolymerization reaction of the present invention can proceed smoothly within this pressure and temperature range, reducing the harshness of the copolymerization reaction.

[0056] Furthermore, the above copolymerization reaction can be carried out in a solvent system. Specifically, the solvent can be selected from at least one of toluene, n-hexane, dichloromethane, and dichloroethane. Toluene, dichloromethane, and dichloroethane are polar solvents, which facilitate the insertion of methacrylic acid and enhance the activity of polar copolymerization. The above copolymerization reaction can also be carried out using n-hexane, a commonly used industrial solvent with the advantages of easy availability and low toxicity.

[0057] A third aspect of the present invention provides a copolymer of ethylene and methyl methacrylate, which is prepared by the copolymerization method provided in the second aspect of the present invention.

[0058] The copolymer of the present invention is prepared by the copolymerization method provided in the second aspect of the present invention, and therefore has a high molecular weight, which can meet the formulation requirements of existing resin processing equipment and commercial plastics. At the same time, the insertion rate of methyl ester and methyl acrylate is adjustable, and it has a wide range of applications.

[0059] The catalyst for copolymerization of ethylene and methyl methacrylate provided by the present invention will be further described in detail below with reference to specific embodiments.

[0060] It should be noted that, unless otherwise specified, the raw materials used in the following embodiments can be obtained by commercial purchase or conventional methods, and the experimental methods without specific conditions are all conventional methods and conditions well known in the art.

[0061] Example 1

[0062] 1. The main catalyst used in this embodiment for the copolymerization of ethylene and methyl methacrylate was obtained by compounding compound 1 and compound 2 in a molar ratio of 1:49. The main catalyst obtained by compounding is labeled as main catalyst A.

[0063]

[0064] 2. The preparation method of the ethylene-methyl methacrylate copolymer in this embodiment includes the following steps:

[0065] 1) In a clean and dry 150 mL autoclave, add 50 mL of toluene and 40 μmol of the main catalyst A under an ethylene atmosphere. Then, introduce ethylene until the pressure reaches 0.05 MPa. Place the autoclave in a 60 °C (copolymerization temperature) oil bath and stir electromagnetically. While stirring, add 50 mmol of methyl methacrylate and 7.85 mL of MAO (concentration 1.53 mol / L). The Al / Ni molar ratio is 300:1. Continue to introduce ethylene at a pressure of 4 MPa (copolymerization pressure) and stop introducing ethylene after 1 hour.

[0066] 2) Depressurize and treat with a 5% hydrochloric acid ethanol solution. After washing, filtering and drying, ethylene and methyl methacrylate copolymer is obtained.

[0067] Example 2

[0068] 1. The main catalyst used in this embodiment for the copolymerization of ethylene and methyl methacrylate is basically the same as that in Example 1. The difference is that the molar ratio of compound 1 to compound 2 is 49:1, and the main catalyst obtained by the compounding is labeled as main catalyst B.

[0069] 2. The preparation method of the ethylene-methyl methacrylate copolymer in this embodiment is basically the same as that in Example 1, except that the main catalyst A is replaced with the main catalyst B.

[0070] Example 3

[0071] 1. The main catalyst used in this embodiment for the copolymerization of ethylene and methyl methacrylate is basically the same as that in Example 1. The difference is that the molar ratio of compound 1 to compound 2 is 1:1, and the main catalyst obtained by the compounding is labeled as main catalyst C.

[0072] 2. The preparation method of the ethylene-methyl methacrylate copolymer in this embodiment is basically the same as that in Example 1, except that the main catalyst A is replaced with the main catalyst C.

[0073] Example 4

[0074] 1. The main catalyst used in this embodiment for the copolymerization of ethylene and methyl methacrylate is basically the same as that in Example 1. The difference is that the molar ratio of compound 1 to compound 2 is 3:1, and the main catalyst obtained by the compounding is labeled as main catalyst D.

[0075] 2. The preparation method of the ethylene-methyl methacrylate copolymer in this embodiment is basically the same as that in Example 1, except that the main catalyst A is replaced with the main catalyst D.

[0076] Example 5

[0077] 1. The main catalyst used in this embodiment for the copolymerization of ethylene and methyl methacrylate is the same as that in Example 3.

[0078] 2. The preparation method of the ethylene-methyl methacrylate copolymer in this embodiment is basically the same as that in Example 3, except that 13 mL of MAO (1.53 mol / L) is added and the Al / Ni molar ratio is 500:1.

[0079] Example 6

[0080] 1. The main catalyst used in this embodiment for the copolymerization of ethylene and methyl methacrylate is basically the same as that in Example 1. The difference is that the molar ratio of compound 1 to compound 2 is 10:1, and the main catalyst obtained by the compounding is labeled as main catalyst E.

[0081] 2. The preparation method of the ethylene-methyl methacrylate copolymer in this embodiment is basically the same as that in Example 1, except that the main catalyst A is replaced with the main catalyst E.

[0082] Example 7

[0083] 1. The main catalyst used in this embodiment for the copolymerization of ethylene and methyl methacrylate is the same as that in Example 1. The difference is that the molar ratio of compound 1 to compound 2 is 1:10, and the main catalyst obtained by the compounding is labeled as main catalyst F.

[0084] 2. The preparation method of the ethylene-methyl methacrylate copolymer in this embodiment is basically the same as that in Example 3, except that MAO is replaced with sesquiethylaluminum.

[0085] Example 8

[0086] 1. The main catalyst used in this embodiment for the copolymerization of ethylene and methyl methacrylate is the same as that in Example 7.

[0087] 2. The preparation method of the ethylene-methyl methacrylate copolymer in this embodiment is basically the same as that in Example 7, except that toluene is replaced with dichloromethane and the copolymerization reaction pressure is changed from 4 MPa to 5 MPa.

[0088] Example 9

[0089] 1. The main catalyst used in this embodiment for the copolymerization of ethylene and methyl methacrylate is the same as that in Example 8.

[0090] 2. The preparation method of the ethylene-methyl methacrylate copolymer in this embodiment is basically the same as that in Example 8, except that dichloromethane is replaced with dichloroethane and the copolymerization reaction time is changed from 1 hour to 2 hours.

[0091] Example 10

[0092] 1. The main catalyst used in this embodiment for the copolymerization of ethylene and methyl methacrylate is the same as that in Example 9.

[0093] 2. The preparation method of the ethylene-methyl methacrylate copolymer in this embodiment is basically the same as that in Example 8, except that hexane is replaced with a mixed solution of dichloroethane and toluene, wherein the volume ratio of hexane to toluene in the mixed solution is 1:1.

[0094] Example 11

[0095] 1. The main catalyst used in this embodiment for the copolymerization of ethylene and methyl methacrylate was obtained by compounding compound 3 and compound 4 in a molar ratio of 49:1. The main catalyst obtained by compounding is labeled as main catalyst G.

[0096]

[0097] 2. The preparation method of the ethylene-methyl methacrylate copolymer in this embodiment includes the following steps:

[0098] 1) In a clean and dry 150 mL autoclave, add 50 mL of toluene and 40 μmol of the main catalyst G under an ethylene atmosphere. Then, introduce ethylene until the pressure reaches 0.05 MPa. Place the autoclave in a 40 °C oil bath and perform electromagnetic stirring. While stirring, add 50 mmol of methyl methacrylate and 7.85 mL of MAO (concentration 1.53 mol / L). The Al / Ni molar ratio is 300:1. Continue to introduce ethylene at a pressure of 3 MPa and react for 1 hour, then stop introducing ethylene.

[0099] 2) Depressurize and treat with a 5% hydrochloric acid-ethanol solution. After washing, filtering and drying, 284g of ethylene-methyl methacrylate copolymer is obtained.

[0100] Example 12

[0101] 1. The main catalyst used in this embodiment for the copolymerization of ethylene and methyl methacrylate is basically the same as that in Example 11, except that the molar ratio of compound 3 to compound 4 is 1:49, and the main catalyst obtained by the compounding is labeled as main catalyst H.

[0102] 2. The preparation method of the ethylene-methyl methacrylate copolymer in this embodiment is basically the same as that in Example 11, except that the main catalyst G is replaced with the main catalyst H.

[0103] Example 13

[0104] 1. The main catalyst used in this embodiment for the copolymerization of ethylene and methyl methacrylate is basically the same as that in Example 11, except that the molar ratio of compound 3 to compound 4 is 1:1, and the main catalyst obtained by the compounding is labeled as main catalyst I.

[0105] 2. The preparation method of the ethylene-methyl methacrylate copolymer in this embodiment is basically the same as that in Example 12, except that the main catalyst G is replaced with the main catalyst I.

[0106] Example 14

[0107] 1. The main catalyst used in this embodiment for the copolymerization of ethylene and methyl methacrylate is basically the same as that in Example 11, except that the molar ratio of compound 3 to compound 4 is 30:1, and the main catalyst obtained by the compounding is labeled as main catalyst J.

[0108] 2. The preparation method of the ethylene-methyl methacrylate copolymer in this embodiment is basically the same as that in Example 12, except that the main catalyst G is replaced with the main catalyst J.

[0109] Example 15

[0110] 1. The main catalyst used in this embodiment for the copolymerization of ethylene and methyl methacrylate is basically the same as that in Example 12, except that the molar ratio of compound 3 to compound 4 is 10:1, and the main catalyst obtained by the compounding is labeled as main catalyst K.

[0111] 2. The preparation method of the ethylene-methyl methacrylate copolymer in this embodiment is basically the same as that in Example 12, except that the main catalyst G is replaced with the main catalyst K, MAO is replaced with sesquiethylaluminum, the copolymerization reaction pressure is 2 MPa, and the copolymerization reaction time is 2 h.

[0112] Example 16

[0113] 1. The main catalyst used in this embodiment for the copolymerization of ethylene and methyl methacrylate is basically the same as that in Example 11, except that the molar ratio of compound 3 to compound 4 is 1:10, and the main catalyst obtained by the compounding is labeled as main catalyst L.

[0114] 2. The preparation method of the ethylene-methyl methacrylate copolymer in this embodiment is basically the same as that in Example 13, except that 7.5 mL of MAO (concentration of 1.53 mol / L) and Al / Ni molar ratio of 300:1 are replaced with 13 mL of sesquiethylaluminum (1.53 mol / L) and Al / Ni molar ratio of 500:1, the copolymerization reaction pressure is 2 MPa, and the copolymerization reaction time is 2 hours.

[0115] Example 17

[0116] 1. The main catalyst used in this embodiment for the copolymerization of ethylene and methyl methacrylate is basically the same as that in Example 16, except that the molar ratio of compound 3 to compound 4 is 2:1, and the main catalyst obtained by the compounding is labeled as main catalyst M.

[0117] 2. The preparation method of the ethylene-methyl methacrylate copolymer in this embodiment is basically the same as that in Example 16, except that toluene is replaced with n-hexane, the copolymerization temperature is 60°C, and the copolymerization pressure is 3 MPa.

[0118] Example 18

[0119] 1. The main catalyst used in this embodiment for the copolymerization of ethylene and methyl methacrylate is the same as that in Example 13.

[0120] 2. The preparation method of the ethylene-methyl methacrylate copolymer in this embodiment is basically the same as that in Example 13, except that toluene is replaced with a mixed solution of hexane and dichloroethane, wherein the volume ratio of hexane to dichloroethane is 1:1, MAO is replaced with sesquiethylaluminum, and the copolymerization reaction pressure is 5 MPa.

[0121] Example 19

[0122] 1. The main catalyst used in this embodiment for the copolymerization of ethylene and methyl methacrylate is the same as that in Example 13.

[0123] 2. The preparation method of the ethylene-methyl methacrylate copolymer in this embodiment is basically the same as that in Example 13, except that toluene is replaced with a mixed solution of hexane and dichloroethane, wherein the volume ratio of hexane to dichloroethane is 1:2, MAO is replaced with sesquiethylaluminum, the copolymerization reaction pressure is 10 MPa, and the copolymerization temperature is 60°C.

[0124] Example 20

[0125] 1. The main catalyst used in this embodiment for the copolymerization of ethylene and methyl methacrylate is the same as that in Example 13.

[0126] 2. The preparation method of the ethylene-methyl methacrylate copolymer in this embodiment is basically the same as that in Example 13, except that toluene is replaced with dichloromethane, MAO is replaced with sesquiethylaluminum, the copolymerization reaction pressure is 5 MPa, and the copolymerization temperature is 80°C.

[0127] Example 21

[0128] 1. The main catalyst used in this embodiment for the copolymerization of ethylene and methyl methacrylate was obtained by compounding compound 5 and compound 6 in a molar ratio of 49:1. The main catalyst obtained by compounding is labeled as main catalyst N.

[0129]

[0130] 2. The preparation method of the ethylene-methyl methacrylate copolymer in this embodiment includes the following steps:

[0131] 1) In a clean and dry 150 mL autoclave, add 50 mL of toluene and 40 μmol of N as the main catalyst under an ethylene atmosphere. Then, introduce ethylene until the pressure reaches 0.05 MPa. Place the autoclave in a 60 °C oil bath and stir electromagnetically. While stirring, add 50 mmol of methyl methacrylate and 7.5 mL of sesquiethylaluminum (1.53 mol / L). The Al / Ni molar ratio is 300:1. Continue to introduce ethylene at a pressure of 5 MPa and react for 2 hours. Then, stop introducing ethylene.

[0132] 2) Depressurize and treat with a 5% hydrochloric acid ethanol solution. After washing, filtering and drying, ethylene and methyl methacrylate copolymer is obtained.

[0133] Example 22

[0134] 1. The main catalyst used in this embodiment for the copolymerization of ethylene and methyl methacrylate is basically the same as that in Example 21, except that the molar ratio of compound 5 to compound 6 is 1:49, and the main catalyst obtained by the compounding is labeled as main catalyst O.

[0135] 2. The preparation method of the ethylene-methyl methacrylate copolymer in this embodiment is basically the same as that in Example 21, except that the main catalyst N is replaced with the main catalyst O.

[0136] Example 23

[0137] 1. The main catalyst used in this embodiment for the copolymerization of ethylene and methyl methacrylate is basically the same as that in Example 21, except that the molar ratio of compound 5 to compound 6 is 1:1, and the main catalyst obtained by the compounding is labeled as main catalyst P.

[0138] 2. The preparation method of the ethylene-methyl methacrylate copolymer in this embodiment is basically the same as that in Example 21, except that the main catalyst N is replaced with the main catalyst P.

[0139] Example 24

[0140] 1. The main catalyst used in this embodiment for the copolymerization of ethylene and methyl methacrylate is basically the same as that in Example 21, except that the molar ratio of compound 5 to compound 6 is 10:1, and the main catalyst obtained by the compounding is labeled as main catalyst Q.

[0141] 2. The preparation method of the ethylene-methyl methacrylate copolymer in this embodiment is basically the same as that in Example 21, except that the main catalyst N is replaced with the main catalyst Q.

[0142] Example 25

[0143] 1. The main catalyst used in this embodiment for the copolymerization of ethylene and methyl methacrylate is basically the same as that in Example 21, except that the molar ratio of compound 5 to compound 6 is 1:10, and the main catalyst obtained by the compounding is labeled as main catalyst R.

[0144] 2. The preparation method of the ethylene-methyl methacrylate copolymer in this embodiment is basically the same as that in Example 21, except that the main catalyst N is replaced with the main catalyst R.

[0145] Example 26

[0146] 1. The main catalyst used in this embodiment for the copolymerization of ethylene and methyl methacrylate is basically the same as that in Example 21, except that the molar ratio of compound 5 to compound 6 is 1:5, and the main catalyst obtained by the compounding is labeled as main catalyst S.

[0147] 2. The preparation method of the ethylene-methyl methacrylate copolymer in this embodiment is basically the same as that in Example 21, except that the main catalyst N is replaced with the main catalyst S, sesquiethylaluminum is replaced with MAO, the copolymerization reaction temperature is 40°C, and the amount of methyl methacrylate added is 60 mmol.

[0148] Example 27

[0149] 1. The main catalyst used in this embodiment for the copolymerization of ethylene and methyl methacrylate is the same as that in Example 26.

[0150] 2. The preparation method of the ethylene-methyl methacrylate copolymer in this embodiment is basically the same as that in Example 26, except that toluene is replaced with dichloroethane, the amount of MAO added is 13 mL (1.53 M), and the Al / Ni molar ratio is 500:1.

[0151] Example 28

[0152] 1. The main catalyst used in this embodiment for the copolymerization of ethylene and methyl methacrylate is basically the same as that in Example 27, except that the molar ratio of compound 5 to compound 6 is 2:1, and the main catalyst obtained by the compounding is labeled as main catalyst T.

[0153] 2. The preparation method of the ethylene-methyl methacrylate copolymer in this embodiment is basically the same as that in Example 21, except that the main catalyst N is replaced with the main catalyst T, the dichloroethane is replaced with toluene, the copolymerization reaction pressure is 3 MPa, and the copolymerization reaction temperature is 80°C.

[0154] Example 29

[0155] 1. The main catalyst used in this embodiment for the copolymerization of ethylene and methyl methacrylate is the same as that in Example 28.

[0156] 2. The preparation method of the ethylene-methyl methacrylate copolymer in this embodiment is basically the same as that in Example 28, except that toluene is replaced with a mixed solution of dichloromethane and n-hexane, wherein the volume ratio of dichloromethane to n-hexane is 1:3, and the copolymerization reaction time is 4h.

[0157] Example 30

[0158] 1. The main catalyst used in this embodiment for the copolymerization of ethylene and methyl methacrylate is the same as that in Example 23.

[0159] 2. The preparation method of the ethylene-methyl methacrylate copolymer in this embodiment is basically the same as that in Example 23, except that toluene is replaced with dichloroethane, 7.5 mL of sesquiethylaluminum (1.53 mol / L) and Al / Ni molar ratio of 300:1 is replaced with 13 mL of MAO (1.53 mol / L) and Al / Ni molar ratio of 500:1, the copolymerization reaction time is 6 hours, and the amount of methacrylic acid added is 30 mmol.

[0160] Example 31

[0161] 1. The main catalyst used in this embodiment for the copolymerization of ethylene and methyl methacrylate was obtained by compounding compound 7 and compound 8 in a molar ratio of 1:49. The main catalyst obtained by compounding is labeled as main catalyst U.

[0162]

[0163] 2. The preparation method of the ethylene-methyl methacrylate copolymer in this embodiment includes the following steps: In a clean and dry 150 mL autoclave, 50 mL of toluene and 40 μmol of the main catalyst U are added under an ethylene atmosphere. Ethylene is then introduced until the pressure reaches 0.05 MPa. The autoclave is placed in a 60°C (copolymerization temperature) oil bath for electromagnetic stirring. While stirring, 50 mmol of methyl methacrylate and 13 mL of MAO (concentration 1.53 mol / L) are added, with an Al / Ni molar ratio of 500:1. Ethylene is continued to be introduced at a pressure of 4 MPa (copolymerization pressure) for 1 hour, after which the ethylene supply is stopped. The pressure is released, and the product is treated with a 5% (v / v) hydrochloric acid-ethanol solution. After washing, filtration, and drying, the ethylene-methyl methacrylate copolymer is obtained.

[0164] Example 32

[0165] 1. The main catalyst used in this embodiment for the copolymerization of ethylene and methyl methacrylate was obtained by compounding compound 9 and compound 10 in a molar ratio of 49:1. The main catalyst obtained by compounding is labeled as main catalyst V.

[0166]

[0167] 2. The preparation method of the ethylene-methyl methacrylate copolymer in this embodiment includes the following steps: In a clean and dry 150 mL autoclave, 50 mL of toluene and 40 μmol of the main catalyst V are added under an ethylene atmosphere. Ethylene is then introduced until the pressure reaches 0.05 MPa. The autoclave is placed in a 40°C oil bath for electromagnetic stirring. While stirring, 50 mmol of methyl methacrylate and 7.85 mL of MAO (concentration 1.53 mol / L) are added, with an Al / Ni molar ratio of 300:1. Ethylene is continued to be introduced at a pressure of 3 MPa for 1 hour, after which the ethylene supply is stopped. The pressure is released, and the mixture is treated with a 5% (v / v) hydrochloric acid-ethanol solution. After washing, filtration, and drying, 284 g of the ethylene-methyl methacrylate copolymer is obtained.

[0168] Example 33

[0169] 1. The main catalyst used in this embodiment for the copolymerization of ethylene and methyl methacrylate was obtained by compounding compound 11 and compound 12 in a molar ratio of 49:1. The main catalyst obtained by compounding is labeled as main catalyst W.

[0170]

[0171] 2. The preparation method of the ethylene-methyl methacrylate copolymer in this embodiment includes the following steps: In a clean and dry 150 mL autoclave, 50 mL of toluene and 40 μmol of the main catalyst W are added under an ethylene atmosphere. Ethylene is then introduced until the pressure reaches 0.05 MPa. The autoclave is placed in a 60°C oil bath for electromagnetic stirring. While stirring, 50 mmol of methyl methacrylate and 7.85 mL of sesquiethylaluminum (1.53 mol / L) are added, with an Al / Ni molar ratio of 300:1. Ethylene is continued to be introduced at a pressure of 5 MPa for 2 hours, after which the ethylene supply is stopped. The pressure is released, and the product is treated with a 5% (v / v) hydrochloric acid-ethanol solution. After washing, filtration, and drying, the ethylene-methyl methacrylate copolymer is obtained.

[0172] Example 34

[0173] 1. The main catalyst used in this embodiment for the copolymerization of ethylene and methyl methacrylate is the same as that in Example 3.

[0174] 2. The preparation method of the ethylene-methyl methacrylate copolymer in this embodiment includes the following steps: In a clean and dry 150 mL autoclave, 50 mL of toluene and 40 μmol of the main catalyst C are added under an ethylene atmosphere. Ethylene is then introduced until the pressure reaches 0.05 MPa. The autoclave is placed in a 60°C oil bath for electromagnetic stirring. While stirring, 50 mmol of methyl methacrylate and 19.63 mL of MAO (1.53 mol / L) are added, with an Al / Ni molar ratio of 750:1. Ethylene is continued to be introduced at a pressure of 4 MPa for 1 hour, after which the ethylene supply is stopped. The pressure is released, and the product is treated with a 5% (v / v) hydrochloric acid-ethanol solution. After washing, filtration, and drying, the ethylene-methyl methacrylate copolymer is obtained.

[0175] Example 35

[0176] 1. The main catalyst used in this embodiment for the copolymerization of ethylene and methyl methacrylate is the same as that in Example 3.

[0177] 2. The preparation method of the ethylene-methyl methacrylate copolymer in this embodiment includes the following steps: In a clean and dry 150 mL autoclave, 50 mL of toluene and 40 μmol of the main catalyst C are added under an ethylene atmosphere. Ethylene is then introduced until the pressure reaches 0.05 MPa. The autoclave is placed in a 60°C oil bath for electromagnetic stirring. While stirring, 50 mmol of methyl methacrylate and 52.33 mL of sesquiethylaluminum (1.53 mol / L) are added, with an Al / Ni molar ratio of 2000:1. Ethylene is continued to be introduced at a pressure of 4 MPa for 1 hour, after which the ethylene supply is stopped. The pressure is released, and the product is treated with a 5% (v / v) hydrochloric acid-ethanol solution. After washing, filtration, and drying, the ethylene-methyl methacrylate copolymer is obtained.

[0178] Comparative Example 1

[0179] 1. The main catalyst used in this comparative example for the copolymerization of ethylene and methyl methacrylate is compound 5, labeled as main catalyst X1.

[0180] 2. The preparation method of the ethylene-methacrylate copolymer in this embodiment includes the following steps:

[0181] 1) In a clean and dry 150 mL autoclave, add 50 mL of toluene and 140 μmol of catalyst under an ethylene atmosphere. Then, introduce ethylene until the pressure reaches 0.05 MPa. Place the autoclave in a 60 °C oil bath and stir electromagnetically. While stirring, add 30 mmol of methyl methacrylate and 7.5 mL of MAO (1.53 mol / L). The Al / Ni molar ratio is 300:1. Continue to introduce ethylene at a pressure of 5 MPa and react for 1 hour. Then, stop introducing ethylene.

[0182] 2) Depressurize and treat with a 5% hydrochloric acid ethanol solution. After washing, filtering and drying, ethylene and methyl methacrylate copolymer is obtained.

[0183] Comparative Example 2

[0184] 1. The main catalyst used in this comparative example for the copolymerization of ethylene and methyl methacrylate is compound 6, labeled as main catalyst X2.

[0185] 2. The preparation method of the ethylene-methacrylate copolymer in this embodiment includes the following steps:

[0186] 1) In a clean and dry 150 mL autoclave, add 50 mL of toluene and 240 μmol of catalyst under an ethylene atmosphere. Then, introduce ethylene until the pressure reaches 0.05 MPa. Place the autoclave in a 60 °C oil bath and stir electromagnetically. While stirring, add 30 mmol of methyl methacrylate and 7.5 mL of MAO (1.53 mol / L). The Al / Ni molar ratio is 300:1. Continue to introduce ethylene at a pressure of 5 MPa and react for 1 hour. Then, stop introducing ethylene.

[0187] 2) Depressurize and treat with a 5% hydrochloric acid ethanol solution. After washing, filtering and drying, ethylene and methyl methacrylate copolymer is obtained.

[0188] Comparative Example 3

[0189] 1. In this embodiment, the main catalyst used for the copolymerization of ethylene and methyl methacrylate is compound 13, labeled as main catalyst X3.

[0190]

[0191] 2. The preparation method of the ethylene-methyl methacrylate copolymer in this embodiment includes the following steps:

[0192] 1) In a clean and dry 150 mL autoclave, add 50 mL of toluene and 340 μmol of the main catalyst under an ethylene atmosphere. Then, introduce ethylene until the pressure reaches 0.05 MPa. Place the autoclave in a 60 °C oil bath for electromagnetic stirring. While stirring, add 50 mmol of methyl methacrylate and 7.85 mL of MAO (1.53 mol / L). The Al / Ni molar ratio is 300:1. Continue to introduce ethylene at a pressure of 5 MPa and react for 1 hour. Then, stop introducing ethylene.

[0193] 2) Depressurize and treat with a 5% hydrochloric acid ethanol solution. After washing, filtering and drying, ethylene and methyl methacrylate copolymer is obtained.

[0194] Comparative Example 4

[0195] 1. In this embodiment, the main catalyst used for the copolymerization of ethylene and methyl methacrylate is compound 15, labeled as main catalyst X4.

[0196]

[0197] 2. The preparation method of the ethylene-methyl methacrylate copolymer in this embodiment includes the following steps:

[0198] 1) In a clean and dry 150 mL autoclave, add 50 mL of toluene and 440 μmol of the main catalyst Y under an ethylene atmosphere. Then, introduce ethylene until the pressure reaches 0.05 MPa. Place the autoclave in a 60 °C oil bath for electromagnetic stirring. While stirring, add 50 mmol of methyl methacrylate and 7.85 mL of MAO (1.53 mol / L). The Al / Ni molar ratio is 300:1. Continue to introduce ethylene at a pressure of 5 MPa and react for 1 hour, then stop introducing ethylene.

[0199] 2) Depressurize and treat with a 5% hydrochloric acid ethanol solution. After washing, filtering and drying, ethylene and methyl methacrylate copolymer is obtained.

[0200] Comparative Example 5

[0201] 1. In this embodiment, the main catalyst used for the copolymerization of ethylene and methyl methacrylate is compound 15, labeled as main catalyst X5.

[0202]

[0203] 2. The preparation method of the ethylene-methyl methacrylate copolymer in this embodiment includes the following steps:

[0204] 1) In a clean and dry 150 mL autoclave, add 50 mL of toluene and 540 μmol of the main catalyst X under an ethylene atmosphere. Then, introduce ethylene until the pressure reaches 0.05 MPa. Place the autoclave in a 45 °C oil bath for electromagnetic stirring. While stirring, add 47 mmol of methyl methacrylate and 3.9 mL of MAO (1.53 mol / L). The Al / Ni molar ratio is 150:1. Continue to introduce ethylene at a pressure of 3 MPa and react for 2 hours. Then, stop introducing ethylene.

[0205] 2) Depressurize and treat with a 5% hydrochloric acid ethanol solution. After washing, filtering and drying, ethylene and methyl methacrylate copolymer is obtained.

[0206] For ease of comparison, the copolymerization reaction conditions of the above examples and comparative examples are listed in Table 1.

[0207] Test case

[0208] The catalytic activity of the catalysts used for the copolymerization of ethylene and methyl methacrylate in Examples 1-35 and Comparative Examples 1-5 was calculated using the following formula:

[0209] Catalytic activity = Copolymer mass (g) / (Main catalyst amount (mol) × Reaction time (hours))

[0210] The copolymers of ethylene and methyl methacrylate from Examples 1-35 and Comparative Examples 1-5 were tested for the following parameters:

[0211] Molecular weight determination method: Molecular weight was determined using a Waters 2414 gel permeation chromatography (GPC) system (Waters, Inc., USA). A polystyrene standard was used as the calibration curve. The mobile phase was tetrahydrofuran, the column temperature was 40℃, the sample concentration was 1 mg / mL, the injection volume was 50 μL, the elution time was 40 min, and the flow rate was 1 mL / min. -1 .

[0212] Methods for determining and calculating the insertion rate of methyl methacrylate: copolymers 13 C NMR was analyzed using a Bruker 400MHz nuclear magnetic resonance spectrometer from the United States. 13 The peak areas of -CH2 (chemical shift 1.27) and -OCH3 (chemical shift 3.56) on the C NMR spectrum are used to calculate the molar insertion rate of methyl methacrylate in the ethylene-methyl methacrylate copolymer according to the following two formulas.

[0213]

[0214]

[0215] In the two formulas above, N M N represents the molar number of methyl methacrylate in the copolymer. E denoted as the number of moles of ethylene in the copolymer, A as the peak area of ​​-OCH3 (chemical shift 3.56) in methyl methacrylate, B as the peak area of ​​-CH2 (chemical shift 1.27), and E as the molar insertion rate of methyl methacrylate in the copolymer.

[0216] The test results for the above parameters are shown in Table 2.

[0217] Table 1

[0218]

[0219]

[0220]

[0221]

[0222] Note: M represents the metal element in the main catalyst.

[0223] Table 2

[0224]

[0225]

[0226] As can be seen from the data in Table 2, the catalyst of the present invention can produce higher molecular weight copolymers and copolymers with methyl methacrylate when used for copolymerization of ethylene and methacrylic acid.

[0227] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A catalyst for the copolymerization of ethylene and methyl methacrylate, characterized in that, The catalyst includes a main catalyst, which is obtained by combining a compound of formula (I) and a compound of formula (II); The structure of equation (I) is as follows: （I）； R1 and R2 are each independently selected from substituted aryl groups, and the substituents are selected from at least one of C1-C6 alkyl groups and C1-C6 alkoxy groups; R3 and R4 are each independently selected from hydrogen and C1-C4 alkyl groups; M is selected from Ni or Pd; X1 and X2 are each independently selected from halogens, C1-C4 alkyl groups, aryl groups, C2-C4 ethers, and C1-C4 nitriles; The structure of equation (II) is as follows: (II) R5 and R6 are each independently selected from hydrogen, methyl, ethyl, dimethylamino, diethylamino, amino, hydroxyl, and C1~C4 alkoxy groups; R7 and R8 are each independently selected from at least one of hydrogen, C1-C4 alkyl, C1-C4 dialkylamino, amino, hydroxyl, and C1-C4 alkoxy. The molar ratio of the compound of formula (I) to the compound of formula (II) is (1:49) to (49:1).

2. The catalyst according to claim 1, characterized in that, The molar ratio of the compound of formula (I) to the compound of formula (II) is (1:10) to (10:1).

3. The catalyst according to claim 1 or 2, characterized in that, It also includes a co-catalyst, which is selected from aluminum oxanes.

4. The catalyst according to claim 3, characterized in that, The co-catalyst is selected from at least one of methylaluminoxanes.

5. The catalyst according to claim 3, characterized in that, The molar ratio of the metal element in the main catalyst to the aluminum element in the co-catalyst is 1:(50~1000).

6. The catalyst according to claim 5, characterized in that, The molar ratio of the metal element in the main catalyst to the aluminum element in the co-catalyst is 1:(100~500).

7. A method for copolymerizing ethylene with methyl methacrylate, characterized in that, The catalyst described in any one of claims 1-6 is used.

8. The copolymerization method according to claim 7, characterized in that, The copolymerization method includes: copolymerizing ethylene and methyl methacrylate under the catalysis of the catalyst; The copolymerization reaction is carried out at a pressure of ≤10MPa and a temperature of ≤100℃.

9. The copolymerization method according to claim 8, characterized in that, The solvent for the copolymerization reaction is selected from at least one of toluene, n-hexane, dichloromethane, and dichloroethane.

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