Metal complex catalyst as well as preparation method and application thereof

Abstract

The invention discloses a metal complex catalyst as well as a preparation method and application thereof. The metal complex catalyst has a structural expression as shown in the specification. When the gold complex catalyst disclosed by the invention is applied to catalysis of ethylene and alpha-olefin copolymerization, the insertion rate of a comonomer can be greatly improved on the premise of ensuring the high molecular weight of a polymer, and the gold complex catalyst has a good industrial application prospect. # imgabs0 #

Description

Technical Field

[0001] The present invention relates to polyolefin catalysts, and particularly to a metal complex catalyst, a preparation method thereof, and an application thereof. Background Art

[0002] Due to its high catalytic activity and excellent polymer structure regulation ability, the late metallocene catalyst has been widely used in the preparation of polyolefin products. Especially in the research and development and production of linear low-density polyethylene, vinyl or propylene-based elastomers, the late metallocene catalyst has high application value. Compared with the traditional Z-N catalyst, the late metallocene catalyst has a single active catalytic center, so the polymer has a narrow molecular weight distribution and good mechanical properties. In addition, the structure of this type of catalyst can be highly adjusted, and the properties of the polymer can be adjusted by changing the catalyst structure.

[0003] Since Dow and Exxon began to apply CGC catalysts to the industrial production of POE (EP0416815A2, US5026798A), a large number of metallocene catalysts have been developed (EP0842939B1, WO1996013529A1, US6124487A). At the same time, Mitsui Chemicals developed the late metallocene catalyst FI catalyst (Chem. Lett. 1999, 10, 1065). In actual industrial applications, we found that when the content of comonomer in the polymer does not meet the requirements, increasing the concentration of comonomer in the polymerization reaction is the most common adjustment method. However, when the comonomer concentration exceeds a certain value, due to the large transfer of β-H on the polymer chain to the comonomer, the molecular weight of the polymer will significantly decrease, resulting in the melt index of the polymer not meeting the standard, thus affecting downstream applications. Summary of the Invention

[0004] In order to solve the above technical problems, the present invention provides a metal complex catalyst, a preparation method thereof, and an application thereof. The unique nitrogen-containing bridged ring structure of the metal complex catalyst shields the metal, reduces the meta-link effect, so that when the polymerization reaction is carried out in the presence of a high concentration of comonomer, the polymerization reaction is still not easily terminated, thereby showing the characteristics of high polymer insertion rate and high molecular weight.

[0005] A metal complex catalyst has a structural expression shown in Formula I:

[0006]

[0007] In Formula I, M is selected from early transition metals, preferably selected from Group IVB metals, more preferably selected from Ti, Zr or Hf;

[0008] R1, R2, R3, and R4 each independently include the following groups: hydrogen, halogen, C1-C 10alkyl group, aryl group having 6 to C 30 are each independently selected from fluorine, methyl, ethyl, isopropyl, tert-butyl, trifluoromethyl;

[0009] X is selected from halogen, C1-C8 alkyl group, benzyl group, dimethylamino group, and is preferably selected from chlorine, methyl, benzyl group, dimethylamino group.

[0010] As a preferred embodiment of the present invention, the metal complex is selected from at least one of substances having the following structural formulas:

[0011]

[0012]

[0013] A method for preparing a metal complex catalyst as described above, comprising: adding compound 1 and alkyllithium in an ultra-dry organic solvent, reacting for a period of time first, then adding compound 2 and reacting for a period of time, and finally adding metal salt MX, filtering and crystallizing after the reaction to obtain the metal complex shown in formula I;

[0014]

[0015] In the formula, the definitions of R1, R2, R3, and R4 are the same as those in formula I above;

[0016] In MX, M is selected from early transition metals, preferably group IVB metals, more preferably Ti, Zr or Hf; X represents any one of halogen, C1-C8 alkyl group, benzyl group, dimethylamino group, preferably chlorine, methyl, benzyl group or dimethylamino group, and the ratio of the two satisfies the valence balance of the substance.

[0017] Preferably, the metal salt MX is selected from TiCl4, ZrCl4 or HfCl4.

[0018] As a preferred embodiment of the present invention, the molar ratio of compound 1, alkyllithium, compound 2, and MX is 1:(2-3):(1-1.5):(0.5-1), preferably 1:(2.2-2.4):(1-1.2):(0.5-0.6);

[0019] Preferably, compound 1 is selected from one or more of 2-bromo-4-methylphenol, 2-bromo-4-tert-butylphenol, 2-bromo-6-fluorophenol, 2-bromo-3-isopropylphenol, 2-bromo-5-chlorophenol, 2-bromo-3-n-butylphenol;

[0020] Preferably, the alkyllithium is one or more of n-butyllithium, n-hexyllithium, tert-butyllithium.

[0021] As a preferred embodiment of the present invention, the super-dry organic solvent is one or more of tetrahydrofuran, diethyl ether, pentane, cyclopentane, n-hexane, cyclohexane, n-heptane, methylcyclohexane, toluene, xylene, methyl tert-butyl ether, and ethylene glycol dimethyl ether.

[0022] As a preferred embodiment of the present invention, the reaction temperature is from -30°C to 30°C, preferably from -10°C to 20°C, and more preferably from 0 - 10°C.

[0023] As a preferred embodiment of the present invention, after adding Compound 1 and alkyllithium, the reaction is first carried out for 1 - 6 h, preferably 1 - 4 h, and more preferably 1 - 2 h;

[0024] Preferably, after adding Compound 2, the reaction is carried out for another 1 - 8 h, preferably 2 - 6 h, and more preferably 3 - 5 h;

[0025] Preferably, after adding the metal salt MX, the reaction is carried out for 1 - 24 h, preferably 3 - 15 h, and more preferably 5 - 10 h.

[0026] In the present invention, after the reaction is completed, it may further include post-treatment and purification processes such as recrystallization and silica gel column chromatography, which are conventional operations in the art and are not specifically limited in the present invention.

[0027] A catalyst composition comprising the metal complex catalyst described above or the metal complex catalyst prepared by the method described above and an aluminum activator;

[0028] Preferably, the aluminum activator is an aluminoxane or a modified aluminoxane, preferably one or more of methylaluminoxane, isobutyl-modified methylaluminoxane, and octyl-modified methylaluminoxane;

[0029] Preferably, the molar ratio of the aluminum activator to the metal complex catalyst, calculated as Al / M, is (1 - 10000):1, preferably (200 - 5000):1.

[0030] An olefin polymerization method, in the presence of the catalyst composition described above, copolymerizes ethylene with an α-olefin to prepare a polyolefin.

[0031] The α-olefin is one or more of 1-butene, 1-hexene, and 1-octene.

[0032] As a preferred embodiment of the present invention, the copolymerization reaction temperature is 100 - 200°C, preferably 120 - 190°C, and more preferably 140 - 180°C, and the polymerization reaction pressure is 1 - 5 MPa, preferably 2 - 4 MPa, and more preferably 2 - 3 MPa.

[0033] Preferably, the copolymerization reaction is carried out in an organic solvent selected from one or more of Isopar E, toluene, n-hexane, and cyclohexane.

[0034] In the application of the gold complex catalyst disclosed by the present invention in the copolymerization of ethylene and α-olefins, on the premise of ensuring the high molecular weight of the polymer, it can also greatly improve the insertion rate of the comonomer, and has good prospects for industrial application. Specific Embodiments

[0035] The present invention will be further described below through specific embodiments. The embodiments described in the present invention are only for the purpose of illustrating the present invention and do not limit the scope of the present invention.

[0036] The materials, reagents, etc. used in the following embodiments are obtained from commercial sources unless otherwise specified. The specific information is as follows:

[0037] The materials, reagents, etc. used in the following embodiments are obtained from commercial sources unless otherwise specified. The specific information is as follows:

[0038] n-Hexane: AR, Innochem

[0039] n-Butyllithium: AR, Acros

[0040] ZrCl4: AR, Yanfeng Technology

[0041] Tetrahydrofuran: AR, Innochem

[0042] Diethyl ether: AR, Innochem

[0043] 4-tert-Butylbromophenol: AR, Luyuan Reagent

[0044] 2-Bromo-4-methylphenol: AR, Aladdin

[0045] 2-Bromo-6-fluorophenol: AR, Merck

[0046] 4-(2-Bromoethyl)pyridine hydrobromide: AR, Macklin

[0047] Pd / C: AR, Innochem

[0048] Isopar E: AR, Exxon Mobil

[0049] MMAO-7 (octyl-modified methylaluminoxane): AR, Nouryon

[0050] In the following embodiments, the compounds are characterized by a nuclear magnetic resonance spectrometer (Brucker ARX-400) and an elemental analyzer (FlashEA1112 micro analyzer).

[0051] The molecular weight and molecular weight distribution of the polymers obtained in the following examples were measured by PL-GPC220 at 150 °C. Three PLgel 10μm MIXED-B separation columns in series were used, and 1,2,4-trichlorobenzene was used as the solvent.

[0052] The example complexes were synthesized according to the following reaction route:

[0053]

[0054] Among them, compound 2 (3-bromoethyl-2,3,4,5-tetrahydropyridine) was synthesized by the following method:

[0055] Add 150 ml of toluene to a 500 ml thick-walled pressure-resistant bottle, then add 2.67 g (0.01 mol) of 4-(2-bromoethyl)pyridine hydrobromide, then add 2 g of Pd / C (10%, 2 mmol), and then displace the reaction system with hydrogen 3 times and finally adjust the pressure to 3 bar and the temperature to 50 °C. After 5 h, stop the reaction, add 100 ml of 2 mol / L NaOH solution to the reaction solution and extract. After concentrating the organic phase, column chromatography was carried out to obtain 1.2 g of the product.

[0056] Nuclear magnetic characterization data of the product: 1 H NMR (C6D6 400 MHz) δ, 1.48 (m, 2H), 1.57 (m, 4H), 1.67 (m, 1H), 2.34 (m, 2H), 2.56 (m, 2H), 5.14 (m, 1H).

[0057]

Example 1

[0058] Under a nitrogen atmosphere, in a 1000 ml round-bottom flask, dissolve 18.7 g (0.1 mol) of 2-bromo-4-methylphenol in 400 ml of tetrahydrofuran, lower the temperature of the reaction solution to 0 °C, and then slowly add 110 ml (0.22 mol) of n-butyllithium (2 mol / L). After 1 h, add 18.8 g (0.1 mol) of 3-bromoethyl-2,3,4,5-tetrahydropyridine. After reacting at 0 °C for 4 h, add 11.6 g (0.05 mol) of ZrCl4. After reacting for 6 h, filter and concentrate the reaction solution, and then recrystallize in n-hexane to obtain 20.6 g of a white solid product.

[0059] Nuclear magnetic characterization data of the product: 11H NMR (C6D6 400 MHz) δ, 1.36 (m, 4H), 1.42 (m, 2H), 1.56 (m, 4H), 1.67 (m, 2H), 1.84 (m, 2H), 2.30 (s, 6H), 2.40 (m, 4H), 2.51 (m, 4H), 3.01 (m, 2H), 6.79 (m, 2H), 6.82 (m, 2H), 6.95 (m, 2H).

[0060]

Example 2

[0061] Under a nitrogen atmosphere, in a 1000 ml round-bottom flask, 22.9 g (0.1 mol) of 2-bromo-4-tert-butylphenol was dissolved in 400 ml of tetrahydrofuran. The temperature of the reaction solution was lowered to 10 °C, and then 120 ml (0.24 mol) of n-butyllithium (2 mol / L) was slowly added. After 2 hours, 22.6 g (0.12 mol) of 3-bromoethyl-2,3,4,5-tetrahydropyridine was added. After reacting at 10 °C for 4 hours, 11.6 g (0.05 mol) of ZrCl4 was added. After reacting for 10 h, the reaction solution was filtered, concentrated, and then recrystallized from n-hexane to obtain 25.2 g of a white solid product.

[0062] Nuclear magnetic characterization data of the product: 1 1H NMR (C6D6 400 MHz) δ, 1.33 (s, 18H), 1.38 (m, 4H), 1.49 (m, 2H), 1.53 (m, 4H), 1.72 (m, 2H), 1.98 (m, 2H), 2.33 (m, 4H), 2.62 (m, 4H), 3.12 (m, 2H), 6.87 (m, 2H), 7.09 (m, 2H), 7.13 (m, 2H).

[0063]

Example 3

[0064] Under a nitrogen atmosphere, in a 1000 ml round-bottom flask, 19.1 g (0.1 mol) of 2-bromo-6-fluorophenol was dissolved in 400 ml of diethyl ether. The temperature of the reaction solution was lowered to 5 °C, and then 110 ml (0.22 mol) of n-butyllithium (2 mol / L) was slowly added. After 1 hour, 18.8 g (0.1 mol) of 3-bromoethyl-2,3,4,5-tetrahydropyridine was added. After reacting at 5 °C for 5 hours, 14.0 g (0.06 mol) of ZrCl4 was added. After reacting for 7 h, the reaction solution was filtered, concentrated, and then recrystallized from n-hexane to obtain 14.8 g of a white solid product.

[0065] Nuclear magnetic characterization data of the product: 11H NMR (C6D6, 400 MHz) δ, 1.33 (m, 4H), 1.40 (m, 2H), 1.55 (m, 4H), 1.72 (m, 2H), 1.92 (m, 2H), 2.35 (m, 4H), 2.62 (m, 4H), 3.05 (m, 2H), 6.82 (m, 2H), 6.88 (m, 2H), 6.96 (m, 2H).

[0066]

Comparative Example 1

[0067] Prepare catalyst X by referring to the method in Example 1.3 of WO2004044018A2.

[0068]

[0069] Refer to the different reaction conditions in Table 1 and apply the metal complexes prepared in Examples 1 - 3 and Comparative Example 1 above to the catalytic polymerization reaction of ethylene and 1 - octene respectively. The method is as follows:

[0070] Encapsulate 0.5 μmol of the metal complex into an ampoule and pre - load it into a 1 L high - pressure polymerization reactor. After drying at 120 °C for 1 h, cool it to 100 °C and add 260 ml of n - hexane and a certain amount of 1 - octene. Then add MMAO - 7 according to a specific Al / M. After raising the temperature of the reaction system to 140 °C, introduce ethylene and set the pressure to 3 Mpa. Break the ampoule and start the polymerization reaction. Keep the reaction pressure and temperature unchanged throughout the reaction process. Stop the reaction after 5 min, replace the ethylene in the reactor with nitrogen and cool it to 100 °C. Connect the reaction solution to a beaker containing 500 ml of ethanol through the bottom discharge port. After discharging, filter and dry the solid polymer.

[0071] Table 1. Reaction conditions and corresponding performance tests of different application examples

[0072]

[0073]

[0074] The above - mentioned are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the method of the present invention, several improvements and supplements can be made, and these improvements and supplements should also be regarded as the protection scope of the present invention.

Claims

1. A metal complex catalyst, characterized in that, It has the structural expression shown in Formula I: In Formula I, M is selected from early transition metals, preferably selected from Group IVB metals, more preferably selected from Ti, Zr or Hf; R1, R2, R3, and R4 each independently include the following groups: hydrogen, halogen, C1-C 10 alkyl, C6-C 30 aryl, preferably each independently selected from fluorine, methyl, ethyl, isopropyl, tert-butyl, trifluoromethyl; X is selected from halogen, C1-C8 alkyl, benzyl, dimethylamino, preferably selected from chlorine, methyl, benzyl, dimethylamino.

2. The metal complex catalyst according to claim 1, wherein The metal complex is selected from at least one of the substances having the following structural formula:

3. A method for preparing the metal complex catalyst as described in Claim 1 or 2, characterized in that Compound 1 and alkyllithium are added to an ultra-dry organic solvent, reacted for a period of time first, then Compound 2 is added and reacted for a period of time, and finally metal salt MX is added. After reaction, filtration and crystallization are carried out to obtain the metal complex shown in Formula I; In the formula, the definitions of R1, R2, R3 and R4 are the same as those in Claim 1; M in MX is selected from early transition metals, preferably Group IVB metals, more preferably Ti, Zr or Hf; X represents any one of halogen, C1-C8 alkyl, benzyl, dimethylamino, preferably chlorine, methyl, benzyl or dimethylamino, and the ratio of the two satisfies the valence balance of the substance.

4. The preparation method of the metal complex catalyst according to claim 3, characterized in that, The molar ratio of Compound 1, alkyllithium, Compound 2, MX is 1:(2-3):(1-1.5):(0.5-1), preferably 1:(2.2-2.4):(1-1.2):(0.5-0.6); Preferably, the alkyllithium is one or more of n-butyllithium, n-hexyllithium, tert-butyllithium.

5. The preparation method of the metal complex catalyst according to claim 3 or 4, characterized in that, The ultra-dry organic solvent is one or more of tetrahydrofuran, diethyl ether, pentane, cyclopentane, n-hexane, cyclohexane, n-heptane, methylcyclohexane, toluene, xylene, methyl tert-butyl ether, ethylene glycol dimethyl ether.

6. The preparation method of the metal complex catalyst according to claim 3 or 4, characterized in that, The reaction temperature is -30°C to 30°C, preferably -10°C to 20°C, more preferably 0-10°C.

7. The preparation method of the metal complex catalyst according to any one of claims 3-6, characterized in that, After adding Compound 1 and alkyllithium, react for 1-6 h first; Preferably, after adding Compound 2, react for another 1-8 h; Preferably, after adding metal salt MX, react for 1-24 h.

8. A catalyst composition, characterized in that, It includes the metal complex catalyst as described in Claim 1 or 2 or the metal complex catalyst prepared by the method as described in any one of Claims 3-7 and an aluminum activator; Preferably, the aluminum activator is an aluminoxane or a modified aluminoxane, preferably one or more of methylaluminoxane, isobutyl-modified methylaluminoxane, octyl-modified methylaluminoxane; Preferably, the molar ratio of the aluminum activator to the metal complex catalyst, calculated as Al / M, is (1-10000):1, preferably (200-5000):

1.

9. A process for olefin polymerization, characterized in that, In the presence of the catalyst composition as described in Claim 8, ethylene and α-olefin are copolymerized to prepare polyolefin.

10. The method according to claim 9, wherein The copolymerization reaction temperature is 100-200°C, and the polymerization reaction pressure is 1-5 MPa.

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