WO2022183467A1

WO2022183467A1 - Heteroaromatic ring tridentate pyridine imine iron complex, preparation method therefor, and application thereof in catalysis of conjugated diene polymerization

Info

Publication number: WO2022183467A1
Application number: PCT/CN2021/079240
Authority: WO
Inventors: 王庆刚; 梁红文; 王亮; 王旭; 张永强; 陈移姣; 周丽; 张君花
Original assignee: 中国科学院青岛生物能源与过程研究所; 中国石油化工股份有限公司; 中石化巴陵石油化工有限公司
Priority date: 2021-03-05
Filing date: 2021-03-05
Publication date: 2022-09-09

Abstract

A heteroaromatic ring tridentate pyridine imine iron complex, a preparation method therefor, and an application thereof in the catalysis of conjugated diene polymerization. The present invention relates to the field of the catalytic polymerization of conjugated dienes. The present invention solves the technical problem of poor thermal stability of existing bidentate ligands such as pyridine imine or pyridine amine. A ligand of the tridentate pyridine imine iron complex of the present invention is a substituent having a heteroatom aromatic ring, and exhibits high activity and high thermal stability in the polymerization of conjugated dienes, and the selectivity and molecular weight of a polymer do not significantly change along with temperature change. The pyridine imine iron complex of the present invention is obtained by means of a mixed reaction between a pyridine imine ligand modified by a heteroatom aromatic ring and anhydrous FeCl32. The iron catalytic system of the present invention is a heteroaromatic ring tridentate pyridine imine iron complex having a clear molecular structure, is simple and easy to prepare, has low costs, and has a wide industrial application prospect.

Description

A kind of heteroaromatic ring tridentate pyridineimide iron complex and its preparation method and its application in catalyzing conjugated diene polymerization

technical field

The invention belongs to the field of catalyzed polymerization of conjugated dienes, and in particular relates to a heteroaromatic ring tridentate pyridineimide iron complex, its preparation method and its application in catalyzed conjugated diene polymerization.

Background technique

Iron is one of the most abundant transition metals in the earth's crust, and iron-based catalysts have received extensive attention in recent years due to their environmental friendliness and economy. The research on the use of iron-based catalysts for the polymerization of conjugated dienes can be traced back to the 1960s. After nearly half a century of development, some preliminary research results have been achieved on the active center structure and polymerization mechanism of iron-based catalysts. Conjugated diene-based polymers have exhibited excellent properties as high-performance green tire materials. Therefore, designing and synthesizing iron complex catalysts with excellent high temperature stability to obtain iron catalytic systems with high activity and high thermal stability has both theoretical research significance and industrial development prospects.

At present, the nitrogen-containing ligands for the polymerization of conjugated olefins catalyzed by iron catalysts are mainly bidentate ligands such as pyridineimine or pyridineamines, which have poor thermal stability and are unfavorable for industrial application.

SUMMARY OF THE INVENTION

In order to solve the technical problem of poor thermal stability of existing bidentate ligands such as pyridineimine or pyridineamines, the present invention provides a heteroaromatic ring tridentate pyridineimide iron complex and a preparation method and the same. Application in catalytic conjugated diene polymerization.

The general structural formula of a kind of heteroaromatic ring tridentate pyridineimide iron complex of the present invention is:

The value of m is 1 or 2, and X is O or S.

Further limited, the specific structure of the heteroaromatic ring tridentate pyridineimide iron complex is:

The preparation method of a kind of heteroaromatic ring tridentate pyridineimide iron complex of the present invention is carried out according to the following steps:

Under an argon atmosphere, in an anhydrous solvent, the heteroaromatic ring tridentate pyridineimine ligand is mixed with anhydrous FeCl ₂ , and the reaction is stirred at 0 to 60 ° C. After the reaction is completed, post-treatment is performed to obtain the heteroaromatic ring tridentate tridentate pyridine imine ligand. Pyridinimide iron complexes.

Further limited, the structural formula of the heteroaromatic ring tridentate pyridineimine ligand is:

Further limited, the molar ratio of the heteroaromatic ring tridentate pyridineimine ligand to anhydrous FeCl ₂ is 1:1.

Further limited, the anhydrous solvent is anhydrous toluene, anhydrous tetrahydrofuran or anhydrous dichloromethane.

Further limited, the ratio of the amount of the heteroaromatic ring tridentate pyridineimine ligand to the volume of the anhydrous solvent is 1.0 mmol: (8-12) mL.

Further limited, the reaction was stirred at 25°C for 20h-24h.

Further limited, the post-processing process is specifically: filtration under argon atmosphere, vacuum drying, washing with n-hexane until the filtrate is clarified, and vacuum drying.

A heteroaromatic ring tridentate pyridineimide iron complex of the present invention is used as a main catalyst to catalyze the polymerization of conjugated diene.

Further limited, the specific steps of the heteroaromatic ring tridentate pyridineimide iron complex as the main catalyst to catalyze the polymerization of conjugated diene are as follows:

Under anhydrous and oxygen-free conditions, the solvent, the main catalyst heteroaromatic ring tridentate pyridineimide iron complex, the cocatalyst and the conjugated diene monomer are added into the reactor in any order, and the polymerization is carried out at 0～100℃ The reaction is carried out for 10 min to 6 h. After the reaction, a quenching agent is added, and the polyconjugated diene is obtained after separation.

Further limited, the polymerization reaction is carried out at 25 to 75° C. for 10 min to 2 h.

Further limited, the solvent is one or more mixtures of toluene, petroleum ether, pentane and n-hexane in any ratio.

Further limited, the volume ratio of the conjugated diene monomer to the solvent is 1:(1-20).

Further limited, the volume ratio of the conjugated diene monomer to the solvent is 2:5.

Further limitation, the cocatalyst is methylaluminoxane or modified methylaluminoxane;

Further limited, the molar ratio of the cocatalyst to the heteroaromatic ring tridentate pyridineimide iron complex is (200-1000):1.

Further limited, the molar ratio of the cocatalyst to the heteroaromatic ring tridentate pyridineimide iron complex is 500:1.

Further limited, the feeding sequence is any one of the following three:

①In the order of cocatalyst, solvent and conjugated diene monomer, add the heteroaromatic ring tridentate pyridineimide iron complex; ②According to the cocatalyst, solvent, and heteroaromatic ring tridentate pyridineimide iron complex Add the conjugated diene monomers in sequence; 3. Add the cocatalyst after adding the heteroaromatic tridentate pyridineimide iron complex, the solvent and the conjugated diene monomer in sequence.

Further limited, the quencher is a mixed solution of methanol and hydrochloric acid, wherein the volume ratio of methanol to hydrochloric acid is 50:1.

Further limited, the volume ratio of the quencher to the solvent is 2:1.

It is further limited that an anti-aging agent is added after the reaction, and the anti-aging agent is an ethanol solution of 2,6-di-tert-butyl-4-methylphenol; wherein 2,6-di-tert-butyl-4-methylphenol The mass concentration of phenol was 1%.

Further limited, the volume ratio of the anti-aging agent to the solvent is 1:5.

Further limited, the number average molecular weight of the obtained polyconjugated diene is 400,000-900,000, the molecular weight distribution is 2.0-4.0; the proportion of cis-1,4 structure is 30%-50%, 3,4-(1, 2-) The proportion of the structure is 50% to 70%.

To further define, the polyconjugated diene is mainly used in tire manufacturing, especially automobile tire manufacturing.

The remarkable effect that the present invention has compared with the prior art:

1) The iron catalytic system of the present invention is a pyridineimide iron complex modified by a heteroatom aromatic ring with a clear molecular structure. The preparation process is simple and the cost is low. It is mainly used for catalyzing the polymerization of conjugated dienes. Compared with iron catalysts, the coordination of heteroatom aromatic rings can enhance the rigidity of the framework and thus enhance the heat resistance of the catalysts.

2) The polyconjugated diene obtained by the present invention has high molecular weight, specifically: its number average molecular weight is 400,000 to 900,000; the microstructure of the polymer can be regulated by adjusting the structure of the main catalyst, specifically cis-1,4 The proportion of the structure is 30% to 50%, and the proportion of the 3,4-(1,2-) structure is 50% to 70%.

3) The iron-based complex catalyst of the present invention has high activity and good thermal stability, the yield is still as high as 91% to 95% at a high temperature of 75 to 100 ° C, and the molecular weight and 3,4-structure do not change significantly with temperature changes, Therefore, it can be used for the production of conjugated dienes under industrial high temperature conditions, and has good industrial value.

Description of drawings

Fig. 1 is the ¹ HNMR of the polyisoprene obtained in Embodiment 7;

Figure 2 is the GPC of the polyisoprene obtained in Embodiment 7.

Detailed ways

Specific embodiment one: the structural formula of a kind of heteroaromatic ring tridentate pyridineimide iron complex of this embodiment is:

Its preparation method is as follows: under argon atmosphere, firstly, 25 mL of Schlenk tube was baked for three times, and then 10 mL of redistilled dichloromethane, 1.0 mmol of anhydrous FeCl ₂ and 1.0 mmol of heteroaromatic tridentate pyridine imine were successively added to it. Body L1 was stirred and reacted at 25°C for 24 h. After the reaction was completed, it was filtered under argon atmosphere, and the dichloromethane was vacuumed to dryness, and then washed twice with 10 mL of distilled n-hexane until the filtrate was clear, and then vacuumed to constant weight to obtain Purple powder, namely heteroaromatic ring tridentate pyridineimide iron complex 1 (referred to as catalyst 1).

Mass spectrometry: C ₁₁ H ₁₀ Cl ₂ FeN ₂ O: [M-Cl] ⁺ : Theory: 276.9826; Found: 276.9828.

Elemental analysis: C ₁₁ H ₁₀ Cl ₂ FeN ₂ O: Theoretical: C, 42.22%; H, 3.22%; N, 8.95%. Found: C, 42.13%; H, 3.42%; N, 8.74%.

Specific embodiment two: the structural formula of a kind of heteroaromatic ring tridentate pyridineimide iron complex of this embodiment is:

Its preparation method is as follows: under argon atmosphere, firstly, 25 mL of Schlenk tube was baked for three times, and then 10 mL of redistilled dichloromethane, 1.0 mmol of anhydrous FeCl ₂ and 1.0 mmol of heteroaromatic tridentate pyridine imine were successively added to it. Body L2 was stirred at 25 °C for 24 h. After the reaction was completed, it was filtered under argon atmosphere, and the dichloromethane was vacuumed to dryness, and then washed twice with 10 mL of distilled n-hexane until the filtrate was clear, and then vacuumed to constant weight to obtain Dark purple powder, namely heteroaromatic ring tridentate pyridineimide iron complex 2 (referred to as catalyst 2).

Mass Spectrometry: C ₁₂ H ₁₂ Cl ₂ FeN ₂ O: [M-Cl] ⁺ : Theory: 290.9982; Found: 290.9983.

Elemental analysis: C ₁₂ H ₁₂ Cl ₂ FeN ₂ O: Theory: C, 44.08%; H, 3.70%; N, 8.57%. Found: C, 44.16%; H, 3.59%; N, 8.68%.

Specific embodiment three: the structural formula of a kind of heteroaromatic ring tridentate pyridineimide iron complex of the present embodiment is:

Its preparation method is as follows: under argon atmosphere, firstly, 25 mL of Schlenk tube was baked for three times, and then 10 mL of redistilled dichloromethane, 1.0 mmol of anhydrous FeCl ₂ and 1.0 mmol of heteroaromatic tridentate pyridine imine were successively added to it. Body L3 was stirred and reacted at 25°C for 24 h. After the reaction was completed, it was filtered under argon atmosphere, and the dichloromethane was vacuumed to dryness, and then washed twice with 10 mL of distilled n-hexane until the filtrate was clear, and then vacuumed to constant weight to obtain Purple powder, namely heteroaromatic ring tridentate pyridineimide iron complex 3 (denoted as catalyst 3).

Mass spectrometry: C ₁₁ H ₁₀ Cl ₂ FeN ₂ S: [M-Cl] ⁺ : Theory: 292.9597; Found: 292.9597.

Elemental analysis: C ₁₁ H ₁₀ Cl ₂ FeN ₂ S: Theory: C, 44.16%; H, 3.06%; N, 8.51%. Found: C, 44.20%; H, 3.08%; N, 8.64%.

Specific embodiment four: the structural formula of a kind of heteroaromatic ring tridentate pyridineimide iron complex of the present embodiment is:

Its preparation method is as follows: under argon atmosphere, firstly, 25 mL of Schlenk tube was baked for three times, and then 10 mL of redistilled dichloromethane, 1.0 mmol of anhydrous FeCl ₂ and 1.0 mmol of heteroaromatic tridentate pyridine imine were successively added to it. Body L4 was stirred and reacted at 25 °C for 24 h. After the reaction was completed, it was filtered under an argon atmosphere, and the dichloromethane was vacuumed to dryness, and then washed twice with 10 mL of distilled n-hexane until the filtrate was clear, and then vacuumed to a constant weight to obtain Purple powder, namely heteroaromatic ring tridentate pyridineimide iron complex 4 (referred to as catalyst 4).

Mass spectrometry: C ₁₂ H ₁₂ Cl ₂ FeN ₂ S: [M-Cl] ⁺ : Theory: 306.9574; Found: 306.9572.

Elemental analysis: C ₁₂ H ₁₂ Cl ₂ FeN ₂ S: Theory: C, 42.02%; H, 3.53%; N, 8.17%. Found: C, 42.08%; H, 3.42%; N, 8.19%.

Specific embodiment five: the application of a kind of heteroaromatic ring tridentate pyridineimide iron complex of this embodiment in catalyzing conjugated diene polymerization is as follows:

Under an argon atmosphere, into a 25 mL Schlenk tube, sequentially add catalyst 1 (3.13 mg, 10 μmol) obtained in Embodiment 1, anhydrous toluene (5 mL), isoprene (2.00 mL, 20.0 mmol), and MAO (5mmol, 500eq.), polymerized at 25°C for 10min, then quenched with 10mL of a mixed solution of methanol and hydrochloric acid (MeOH/HCl volume ratio = 50/1) to quench the reaction and anti-aging agent, and then washed with ethanol three times , to obtain polyisoprene.

Results: Yield: >99%, Number Average Molecular Weight (M _n ): 5.8×10 ⁵ g/mol, Molecular Weight Distribution (PDI): 2.9. The proportion of different structures: cis-1,4-structure accounted for 44%, 3,4-structure accounted for 56%.

Embodiment 6: The difference between this embodiment and Embodiment 5 is that the polymerization is carried out at 50° C. for 10 min, and other steps and parameters are the same as those of Embodiment 5.

Results: Yield: >99%, Number Average Molecular Weight ( _Mn ): ^5.3 x 105 g/mol, Molecular Weight Distribution (PDI): 2.4. The proportion of different structures: 40% for cis-1,4-structure and 60% for 3,4-structure.

Embodiment 7: The difference between this embodiment and Embodiment 5 is that the polymerization is carried out at 75° C. for 10 min, and other steps and parameters are the same as those of Embodiment 5.

Results: Yield: 91%, Number Average Molecular Weight (M _n ): 5.2×10 ⁵ g/mol, Molecular Weight Distribution (PDI): 2.3. The proportion of different structures: cis-1,4-structure accounted for 39%, 3,4-structure accounted for 61%.

Embodiment 8: The difference between this embodiment and the fifth embodiment is that the polymerization is carried out at 100° C. for 2 h, and other steps and parameters are the same as those of the fifth embodiment.

Results: Yield: 95%, Number Average Molecular Weight (M _n ): 4.9×10 ⁵ g/mol, Molecular Weight Distribution (PDI): 2.8. The proportion of different structures: cis-1,4-structure accounted for 43%, 3,4-structure accounted for 57%.

Embodiment 9: The difference between this embodiment and Embodiment 5 is that the solvent is anhydrous n-hexane, and other steps and parameters are the same as those of Embodiment 5.

Results: Yield: >99%, Number Average Molecular Weight ( _Mn ): 6.3 x ¹⁰⁵ g/mol, Molecular Weight Distribution (PDI): 2.1. The proportion of different structures: cis-1,4-structure accounted for 42%, 3,4-structure accounted for 58%.

Embodiment 10: The difference between this embodiment and the fifth embodiment is that the co-catalyst is MMAO, and other steps and parameters are the same as those of the fifth embodiment.

Results: Yield: 95%, Number Average Molecular Weight (M _n ): 4.3×10 ⁵ g/mol, Molecular Weight Distribution (PDI): 3.2. The proportion of different structures: cis-1,4-structure accounted for 48%, 3,4-structure accounted for 52%.

Specific embodiment eleven: the application of a kind of heteroaromatic ring tridentate pyridineimide iron complex of this embodiment in catalyzing conjugated diene polymerization is as follows:

Under an argon atmosphere, into a 25 mL Schlenk tube, sequentially add catalyst 2 (3.27 mg, 10 μmol) obtained in Embodiment 2, anhydrous toluene (5 mL), isoprene (2.00 mL, 20.0 mmol), MAO (5mmol, 500eq.), polymerized at 25°C for 10min, then quenched with 10mL of a mixed solution of methanol and hydrochloric acid (MeOH/HCl volume ratio = 50/1) to quench the reaction and anti-aging agent, and then washed with ethanol three times , to obtain polyisoprene.

Results: Yield: >99%, Number Average Molecular Weight (M _n ): 5.8×10 ⁵ g/mol, Molecular Weight Distribution (PDI): 2.6. The proportion of different structures: 45% for cis-1,4-structure and 55% for 3,4-structure.

Specific embodiment twelve: the application of a kind of heteroaromatic ring tridentate pyridineimide iron complex of this embodiment in catalyzing conjugated diene polymerization is as follows:

Under an argon atmosphere, into a 25 mL Schlenk tube, sequentially add the catalyst 3 (3.28 mg, 10 μmol) obtained in Embodiment 3, anhydrous toluene (5 mL), isoprene (2.00 mL, 20.0 mmol), MAO (5mmol, 500eq.), polymerized at 25°C for 10min, then quenched with 10mL of a mixed solution of methanol and hydrochloric acid (MeOH/HCl volume ratio = 50/1) to quench the reaction and anti-aging agent, and then washed with ethanol three times , to obtain polyisoprene.

Results: Yield: >99%, Number Average Molecular Weight (M _n ): 4.6×10 ⁵ g/mol, Molecular Weight Distribution (PDI): 3.1. The proportion of different structures: 40% for cis-1,4-structure and 60% for 3,4-structure.

Specific embodiment thirteen: the application of a kind of heteroaromatic ring tridentate pyridineimide iron complex of this embodiment in catalytic conjugated diene polymerization is as follows:

Under an argon atmosphere, into a 25 mL Schlenk tube, sequentially add catalyst 4 (3.42 mg, 10 μmol) obtained in Embodiment 4, anhydrous toluene (5 mL), isoprene (2.00 mL, 20.0 mmol), MAO (5mmol, 500eq.), polymerized at 25°C for 10min, then quenched with 10mL of a mixed solution of methanol and hydrochloric acid (MeOH/HCl volume ratio = 50/1) to quench the reaction and anti-aging agent, and then washed with ethanol three times , to obtain polyisoprene.

Results: Yield: >99%, Number Average Molecular Weight (M _n ): 4.8×10 ⁵ g/mol, Molecular Weight Distribution (PDI): 2.6. The proportion of different structures: cis-1,4-structure accounted for 44%, 3,4-structure accounted for 56%.

Embodiment 14: The difference between this embodiment and Embodiment 13 is: isoprene (10.00 mL, 100.0 mmol), and other steps and parameters are the same as Embodiment 13.

Results: Yield: 86%, Number Average Molecular Weight (M _n ): 8.6×10 ⁵ g/mol, Molecular Weight Distribution (PDI): 2.7. The proportion of different structures: cis-1,4-structure accounted for 42%, 3,4-structure accounted for 58%.

Specific embodiment fifteen: the application of a kind of heteroaromatic ring tridentate pyridineimide iron complex of this embodiment in catalyzing conjugated diene polymerization is as follows:

Under an argon atmosphere, into a 25 mL Schlenk tube, sequentially add catalyst 1 (3.13 mg, 10 μmol) obtained in Embodiment 1, anhydrous toluene (5 mL), butadiene (1.75 mL, 20.0 mmol), MAO ( 5mmol, 500eq.), polymerized at 25°C for 10min, then quenched the reaction with a mixed solution of 10mL methanol and hydrochloric acid (MeOH/HCl volume ratio = 50/1) and quenched the reaction with an antioxidant, then washed with ethanol three times, Obtain polybutadiene.

Results: Yield: >99%, Number Average Molecular Weight ( _Mn ): 5.1 x ¹⁰⁵ g/mol, Molecular Weight Distribution (PDI): 2.2. The proportion of different structures: 40% for cis-1,4-structure and 60% for 1,2-structure.

Specific embodiment sixteen: the application of a kind of heteroaromatic ring tridentate pyridineimide iron complex of this embodiment in catalyzing conjugated diene polymerization is as follows:

Under an argon atmosphere, into a 25 mL Schlenk tube, sequentially add catalyst 1 (3.13 mg, 10 μmol) obtained in Embodiment 1, anhydrous toluene (5 mL), butadiene (0.875 mL, 10.0 mmol), isopentane Diene (1 mL, 10.0 mmol), MAO (5 mmol, 500 eq.), polymerized at 25 °C for 10 min, and then quenched with 10 mL of a mixed solution of methanol and hydrochloric acid (MeOH/HCl volume ratio = 50/1) to quench the reaction and anti-aging The reaction was quenched with ethanol and then washed with ethanol three times to obtain the polyconjugated diene.

Results: Yield: >99%, Number Average Molecular Weight ( _Mn ): 4.6 x ¹⁰⁵ g/mol, Molecular Weight Distribution (PDI): 2.0. The proportion of different structures: polyisoprene:polybutadiene=1:1; the microstructure of polyisoprene is: cis-1,4-structure accounts for 40%, 3,4-structure accounts for 60% ; The microstructure of butadiene is: cis-1,4-structure accounts for 50%, 1,2-structure accounts for 50%.

Claims

A kind of heteroaromatic ring tridentate pyridineimide iron complex, it is characterized in that, the general structural formula of this complex is:

The value of m is 1 or 2, and X is O or S.
The described a kind of heteroaromatic ring tridentate pyridineimide iron complex according to claim 1 is characterized in that, the concrete structure of the heteroaromatic ring tridentate pyridineimide iron complex is:
The preparation method of a kind of heteroaromatic ring tridentate pyridineimide iron complex as claimed in claim 1 or 2, is characterized in that, this preparation method is carried out according to the following steps:

Under an argon atmosphere, in an anhydrous solvent, the heteroaromatic ring tridentate pyridineimine ligand is mixed with anhydrous FeCl 2 , and the reaction is stirred at 0 to 60 ° C. After the reaction is completed, post-treatment is performed to obtain the heteroaromatic ring tridentate tridentate pyridine imine ligand. Pyridinimide iron complexes.
The preparation method of a kind of heteroaromatic ring tridentate pyridineimide iron complex according to claim 3, is characterized in that, the structural formula of described heteroaromatic ring tridentate pyridineimide ligand is:
The preparation method of the described a kind of heteroaromatic ring tridentate pyridineimide iron complex according to claim 1, is characterized in that, the molar ratio of described heteroaromatic ring tridentate pyridineimine ligand and anhydrous FeCl 2 is 1:1, the anhydrous solvent is anhydrous toluene, anhydrous tetrahydrofuran or anhydrous dichloromethane, and the ratio of the amount of the heteroaromatic ring tridentate pyridineimine ligand to the volume of the anhydrous solvent is 1.0 mmol: (8～12) mL, stir and react at 25°C for 20h～24h, the post-processing process is as follows: filter under argon atmosphere, vacuum dry, wash with n-hexane until the filtrate is clear, and then vacuum dry .
The application of a kind of heteroaromatic ring tridentate pyridineimide iron complex in catalyzing conjugated diene polymerization according to claim 1 or 2, it is characterized in that, the heteroaromatic ring tridentate pyridineimide iron complex is used as The main catalyst catalyzes the polymerization of conjugated dienes.
The application of a kind of heteroaromatic ring tridentate pyridineimide iron complex in catalyzing conjugated diene polymerization according to claim 6, it is characterized in that, the concrete steps of catalyzing conjugated diene polymerization are as follows:

Under anhydrous and oxygen-free conditions, the solvent, the main catalyst heteroaromatic ring tridentate pyridineimide iron complex, the cocatalyst and the conjugated diene monomer are added into the reactor in any order, and the polymerization is carried out at 0～100℃ The reaction is carried out for 10 min to 6 h. After the reaction, a quenching agent is added, and the polyconjugated diene is obtained after separation.
The application of a heteroaromatic ring tridentate pyridineimide iron complex in catalyzing conjugated diene polymerization according to claim 7, wherein the polymerization reaction is carried out at 25-75°C for 10min-2h, the solvent It is a mixture of one or more of toluene, petroleum ether, pentane and n-hexane, the volume ratio of the conjugated diene monomer to the solvent is 1: (1-20), and the cocatalyst is methyl Aluminoxane or modified methylaluminoxane; the molar ratio of the cocatalyst to the heteroaromatic ring tridentate pyridineimide iron complex is (200-1000):1.
The application of a kind of heteroaromatic ring tridentate pyridineimide iron complex in catalytic conjugated diene polymerization according to claim 7, it is characterized in that, described feeding sequence is any one of the following three kinds: 1. Add the cocatalyst, solvent, and conjugated diene monomer in sequence, and then add the heteroaromatic ring tridentate pyridineimide iron complex; Add the conjugated diene monomers in the order of: 3. Add the cocatalysts in the order of the heteroaromatic tridentate pyridineimide iron complex, the solvent, and the conjugated diene monomers. The quenching agent is a mixed solution of methanol and hydrochloric acid, wherein the volume ratio of methanol and hydrochloric acid is 50:1, the volume ratio of the quenching agent and the solvent is 2:1, and an antiaging agent is also added after the reaction, and the antiaging agent is The aging agent is an ethanol solution of 2,6-di-tert-butyl-4-methylphenol; wherein the mass concentration of 2,6-di-tert-butyl-4-methylphenol is 1%, and the anti-aging agent and solvent The volume ratio is 1:5.
The application of a heteroaromatic ring tridentate pyridineimide iron complex in catalyzing conjugated diene polymerization according to claim 7, wherein the obtained polyconjugated diene has a number-average molecular weight of 400,000-90 The molecular weight distribution is 2.0-4.0; the proportion of cis-1,4 structure in the polyconjugated diene is 30%-50%, and the 3,4-structure and 1,2-structure together account for 50%-70%.