High temperature resistant olefin polymerization catalyst and preparation method thereof

Abstract

The application provides a high-temperature-resistant olefin polymerization catalyst and a preparation method thereof, and relates to the technical field of catalyst design. The high-temperature-resistant olefin polymerization catalyst is prepared by the following steps: preparing an intermediate block by reacting aniline with diphenylmethanol under the catalysis of zinc chloride, preparing a ligand compound by condensation reaction of 2-quinoline formaldehyde and the intermediate block, and finally performing coordination reaction on the mixed ligand compound after the reaction of metal chloride and Grignard reagent, and then recrystallizing to obtain the high-temperature-resistant olefin polymerization catalyst. The application overcomes the defects of the prior art, and by designing a new catalyst, the high-temperature-resistant olefin polymerization catalyst can obtain polymer products with high molecular weight at a high temperature of 160-200 DEG C, while maintaining the same order of magnitude of catalytic activity and similar comonomer insertion capacity as the CGC catalyst.

Description

Technical Field

[0001] The present invention relates to the technical field of catalyst design, and in particular to a high-temperature resistant olefin polymerization catalyst and a preparation method thereof. Background Art

[0002] Polyolefin materials are formed by polymerizing olefin monomers using a variety of catalysts and are widely used in packaging, photovoltaics, and automotive applications. Olefin polymerization catalysts primarily include Zieglar-Nata catalysts, metallocene catalysts, and post-metallocene catalysts. Over the past half century, metallocene catalysts have been widely used in the preparation of polyolefin elastomers due to their high activity and high comonomer insertion rates. This is particularly evident in Dow's EP0416815B1 and Exxon's US5057475A, which demonstrate the outstanding performance of constrained metal configuration metallocene catalysts (CGCs).

[0003] However, metallocene catalysts, such as CGC, experience a rapid decrease in polymer molecular weight at high temperatures, especially above 160°C, leading to poor product performance. In industrial production, high polymerization temperatures improve mass and heat transfer, thereby increasing production efficiency. Therefore, improving the high-temperature resistance of catalysts is crucial for industrial production. Summary of the Invention

[0004] In response to the shortcomings of the existing technology, the present invention provides a high-temperature resistant olefin polymerization catalyst and a preparation method thereof. By designing a new catalyst, it can obtain high molecular weight polymer products at high temperatures of 160-200°C while maintaining the same order of catalytic activity and similar comonomer insertion ability as CGC catalysts.

[0005] To achieve the above objectives, the technical solution of the present invention is implemented through the following technical solutions:

[0006] A high-temperature resistant olefin polymerization catalyst, the chemical structure of the catalyst is shown in any one of the following formulas I and II:

[0007] Formula I: ;

[0008] Formula II: ;

[0009] Wherein R1-R6 are selected from H, C1-C20 alkyl, C6-C20 aryl, substituted aryl; M is a Group IVB or Group VIII transition metal.

[0010] Preferably, R1-R6 are selected from H, methyl, tert-butyl, phenyl, and benzyl; and M is any one of Zr and Hf.

[0011] The preparation method of the high temperature resistant olefin polymerization catalyst comprises the following steps:

[0012] (1) Preparation of intermediate building blocks: Aniline and benzhydrol are reacted under the catalysis of zinc chloride to obtain an intermediate building block for use;

[0013] (2) Preparation of ligand compound: 2-quinolinecarboxaldehyde and the intermediate building block in equal molar mass are subjected to condensation reaction in solvent 1 under acid catalysis, and the ligand compound is obtained by filtration, washing and drying;

[0014] (3) Catalyst preparation: react metal chloride with Grignard reagent in solvent 2 to obtain alkylated metal intermediate, then add ligand compound for coordination reaction, and then recrystallize in recrystallization solvent to obtain catalyst.

[0015] Preferably, in step (1), the molar ratio of aniline to benzhydrol is 1:1-1:2, and the amount of zinc chloride added is 0.1-1.0 eq; the reaction temperature is 120-200°C, and the reaction time is 2-8 h; and after the reaction is completed, dichloromethane / water extraction is performed, the organic phase is dried over anhydrous MgSO4, the product is precipitated with methanol or ethanol, and filtered and dried to obtain a white powdery solid as the intermediate building block.

[0016] Preferably, the acid in step (2) is one or more of formic acid, acetic acid, p-toluenesulfonic acid, and hydrochloric acid; and the solvent 1 is one or more of methanol, ethanol, dichloromethane, tetrahydrofuran, n-hexane, toluene, and ether.

[0017] Preferably, the reaction temperature in step (2) is 25-100° C., and the washing is carried out using one or more of methanol, ethanol, dichloromethane, tetrahydrofuran, ether, n-hexane, acetone, benzene, and toluene.

[0018] Preferably, the amount of each substance used in the reaction in step (3) is that the metal chloride reacts with 4 times the molar equivalent of the Grignard reagent, and then reacts with an equal molar equivalent of the ligand.

[0019] Preferably, the second solvent in step (3) is one or more of dichloromethane, tetrahydrofuran, n-hexane, toluene, and ether; the recrystallization solvent is a mixture of any one or more of dichloromethane, tetrahydrofuran, ether, n-hexane, acetone, benzene, and toluene; and the metal chloride is zirconium tetrachloride or hafnium tetrachloride.

[0020] The specific structure of the intermediate building block is shown in either Formula III or Formula IV:

[0021] Formula III: Formula IV: ;

[0022] The chemical formula of the ligand compound is shown in the following formula V and formula VI:

[0023] Formula V: ;

[0024] Formula VI: .

[0025] The present invention provides a high-temperature resistant olefin polymerization catalyst and a preparation method thereof, which have the following advantages over the prior art:

[0026] The present invention provides a structure and preparation method of a post-metallocene catalyst, which can solve the problem of molecular weight decrease of polymerization products under high temperature of the catalyst. It can obtain high molecular weight polyolefin products at a polymerization temperature of 160°C-200°C, maintaining the same order of catalytic activity and similar comonomer insertion ability as CGC catalysts. DETAILED DESCRIPTION

[0027] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention are clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0028] Example 1:

[0029] Preparation of catalyst C1:

[0030] 1. Synthesis of intermediate building block a:

[0031] A 100 mL round-bottom flask was charged with 2,4-dimethylaniline (50 mM), benzhydrol (50 mM), and zinc chloride (0.4 eq). The reaction was heated to 160°C for 4 h. The solid melted during the heating process, and then the reaction formed a tan solid. The system was cooled to room temperature, extracted with dichloromethane / water, and the organic phase was dried over anhydrous MgSO4. The product was precipitated with methanol or ethanol, filtered, and dried to obtain a white powdery solid in 82% yield.

[0032] The chemical formula of the white powdery solid is:

[0033] 1 H-NMR (CDCl3) δ7.0-7.2 (m, 10H), δ6.7 (s, 1H), δ6.22 (s, 1H), δ5.36 (s, 1H), δ2.00 (s, 3H), δ2.02 (s, 3H) were recorded as intermediate building block a.

[0034] 2. Synthesis of ligand compound L1:

[0035] Dissolve equimolar amounts of 2-quinolinecarboxaldehyde and intermediate building block a in methanol. Add 0.1 eq of p-toluenesulfonic acid as a catalyst. Allow to react overnight at room temperature to yield a yellow precipitate. Wash the precipitate with methanol and filter to obtain ligand compound L1 in a 52% yield.

[0036] The chemical formula of ligand compound L1 is:

[0037] 1 H-NMR(CDCl3)δ8.46(d,1H),δ8.20(d,1H),δ8.03(m,2H),δ7.94(d,1H),δ7.78(d,1H),δ7. 76(d,1H), δ6.98-7.20(m,11H), δ6.52(s,1H), δ5.59(d,1H), δ2.15(d,3H), δ2.04(d,3H).

[0038] 3. Synthesis of Catalyst C1:

[0039] HfCl4 and MeMgBr (4.0 eq) were reacted in toluene to produce HfMe4. Ligand compound L1 (1.0 eq) was immediately added and allowed to react overnight at room temperature. The reaction solution was filtered through a syringe filter, and the filtrate was concentrated and recrystallized from a toluene / n-hexane mixture at -36°C. The resulting brownish-yellow crystals were catalyst C1, with a yield of 36%.

[0040] The structural formula of catalyst C1 is:

[0041] 1 H-NMR(CDCl3)δ8.91(dd,1H),δ8.52(dd,1H),δ7.99(m,3H),δ6.95-7.27(m,11H),δ6.5 3(s,1H), δ6.34(d,1H), δ3.96(s,1H), δ2.29(d,3H), δ2.18(d,3H), δ0.73-0.86(m,9H).

[0042] Example 2:

[0043] Preparation of catalyst C2:

[0044] 1. Synthesis of intermediate building block b:

[0045] A 100 mL round-bottom flask was charged with 4-isopropylaniline (50 mM), benzhydrol (100 mM), and zinc chloride (80 mM). The reaction was heated to 160°C for 4 hours. The solid melted during the heating process, and then the reaction formed a tan solid. The system was cooled to room temperature and extracted with dichloromethane / water. The organic phase was dried over anhydrous MgSO₄. The product was precipitated with methanol or ethanol, filtered, and dried to obtain a beige powdery solid. The yield was 67%.

[0046] The chemical formula of the beige powdery solid is:

[0047] 1 H-NMR (CDCl3) δ7.09-7.27 (m, 20H), δ6.42 (d, 2H), δ5.45 (s, 2H), δ3.27 (s, 2H), δ2.55 (m, 1H), δ0.94 (d, 6H) was recorded as intermediate building block b.

[0048] 2. Synthesis of ligand compound L2:

[0049] Equimolar amounts of 2-quinolinecarboxaldehyde and intermediate building block b were dissolved in methanol and catalyzed by the addition of 0.1 eq of p-toluenesulfonic acid. The reaction was allowed to proceed overnight at room temperature to obtain a yellow precipitate. The yellow precipitate was washed with methanol and filtered to obtain ligand L2 in a yield of 48%.

[0050] The chemical formula of ligand compound L2 is:

[0051] 1 H-NMR (CDCl3) δ8.50(d,1H), δ8.21(d,1H), δ7.83-8.00(m,4H), δ7.54(d,1H), δ6.82-7.30(m,22H), δ5.50(d,2H), δ2.12(d,6H).

[0052] 3. Synthesis of catalyst C2:

[0053] HfCl4 was reacted with MeMgBr (4.0 eq) in toluene to produce HfMe4. Ligand compound L2 (1.0 eq) was immediately added and allowed to react overnight at room temperature. The reaction solution was filtered through a syringe filter. The filtrate was concentrated and recrystallized from a toluene / n-hexane mixture at -36°C. Brown-yellow crystals were obtained in a 27% yield.

[0054] The structural formula of catalyst C2 is:

[0055] 1H-NMR (CDCl3) δ9.12 (dd, 1H), δ8.88 (dd, 1H), δ7.80-8.51 (m, 4H), δ6.55-7. 32(m,22H), δ4.01(s,1H), δ2.02(d,3H), δ1.21(d,3H), δ0.82-0.91(m,9H).

[0056] experiment:

[0057] In a glove box, a 350 mL thick-walled glass reactor was charged with 2 μmol of the corresponding catalyst and 2.4 μmol of the co-catalyst triphenylcarbonium tetrakis(pentafluorophenyl)borate. The reactor was connected to a high-pressure line for nitrogen displacement, followed by three displacements with ethylene. After reaching the reaction temperature, a mixture of toluene and 1-octene was injected via syringe. Ethylene gas was introduced at a pressure of 5 atm and maintained continuously throughout the experiment. After the reaction was completed, the pressure was released and ethanol was injected to terminate the reaction. The polymer solution was transferred to excess ethanol to precipitate the polymer, which was then filtered, washed with ethanol, and vacuum dried overnight to obtain the desired polymer.

[0058] The specific catalytic parameters and results are shown in the following table:

[0059]

[0060] The above catalyst CGC was purchased from Anhui Dunmao New Material Technology Co., Ltd., Cas162763-85-1;

[0061] From the above tests, it can be seen that catalyst C1 and catalyst C2 both have good catalytic effects at a temperature of 120-180°C.

[0062] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A high temperature resistant olefin polymerization catalyst, characterized in that The chemical structure of the catalyst is shown in any one of the following formulas I and II: Formula I: ; Formula II: ; Wherein, R1-R6 are selected from H, methyl, and tert-butyl; and M is a Group IVB transition metal.

2. The catalyst according to claim 1, characterized in that: The M is any one of Zr and Hf.

3. A method for preparing the catalyst according to any one of claims 1-2, characterized in that: The preparation method comprises the following steps: (1) Preparation of intermediate building blocks: Aniline and benzhydrol are reacted under the catalysis of zinc chloride to obtain an intermediate building block for use; (2) Preparation of ligand compound: 2-quinolinecarboxaldehyde and the intermediate building block in equal molar mass are subjected to condensation reaction in solvent 1 under acid catalysis, and the ligand compound is obtained by filtration, washing and drying; (3) Catalyst preparation: react metal chloride with Grignard reagent in solvent 2 to obtain alkylated metal intermediate, then add ligand compound for coordination reaction, and then recrystallize in recrystallization solvent to obtain catalyst.

4. The preparation method according to claim 3, wherein: In step (1), the molar ratio of aniline to benzhydrol is 1:1-1:3, and the amount of zinc chloride added is 0.1-1.0eq; the reaction temperature is 120-200°C, and the reaction time is 2-8h; and after the reaction is completed, dichloromethane / water extraction is performed, the organic phase is dried over anhydrous MgSO4, the product is precipitated with methanol or ethanol, and filtered and dried to obtain a white powdery solid as an intermediate building block.

5. The preparation method according to claim 3, wherein: In step (2), the acid is one or more of formic acid, acetic acid, p-toluenesulfonic acid, and hydrochloric acid; and the solvent 1 is one or more of methanol, ethanol, dichloromethane, tetrahydrofuran, n-hexane, toluene, and ether.

6. The preparation method according to claim 3, wherein: The reaction temperature in step (2) is 25-100° C., and one or more of methanol, ethanol, dichloromethane, tetrahydrofuran, ether, n-hexane, acetone, benzene, and toluene are used for washing.

7. The preparation method according to claim 3, wherein: The amount of each substance used in the reaction of step (3) is that the metal chloride reacts with 4 times the molar equivalent of the Grignard reagent, and then reacts with an equal molar equivalent of the ligand.

8. The preparation method according to claim 3, wherein: The second solvent in step (3) is one or more of dichloromethane, tetrahydrofuran, n-hexane, toluene, and ether; the recrystallization solvent is a mixture of any one or more of dichloromethane, tetrahydrofuran, ether, n-hexane, acetone, benzene, and toluene; and the metal chloride is zirconium tetrachloride or hafnium tetrachloride.

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