Metallocene complex as well as preparation method and application thereof

Abstract

The invention discloses a metallocene complex as well as a preparation method and application thereof. The metallocene complex has a structure as shown in a formula I in the specification. When the metallocene complex is matched with a cocatalyst (such as MAO), the catalytic activity of a polymer can be remarkably improved. Even at the temperature of 110 DEG C, the complex provided by the invention still has relatively high catalytic activity.

Description

Technical Field

[0001] This invention belongs to the field of catalyst technology, specifically relating to a metallocene complex, its preparation method, and its application as a catalyst in the homopolymerization or copolymerization of ethylene. Background Technology

[0002] Olefin polymerization catalyst systems can be classified into Ziegler-Natta catalysts and metallocene catalysts, and these highly active catalyst systems have been developed based on their characteristics. Ziegler-Natta catalysts have been widely used in commercial processes since their development in the 1950s. However, because Ziegler-Natta catalysts are multi-site catalysts containing multiple active sites, they result in polymers with a wide molecular weight distribution. Furthermore, due to the non-uniform compositional distribution of the comonomers, it is difficult to obtain the desired physical properties.

[0003] Meanwhile, metallocene catalysts include main catalysts with transition metal compounds as the main component and co-catalysts with organometallic compounds with aluminum as the main component. Using metallocene catalysts can yield polyolefin elastomers with very uniform molecular weight and chemical composition distributions, and the molecular structure and molecular weight of the polymer can be highly controlled by adjusting the catalyst structure.

[0004] Existing technologies have been used to study metallocene catalysts, but their catalytic activity still needs to be improved. Summary of the Invention

[0005] Based on this, the present invention provides a metallocene complex, which exhibits high catalytic activity as a catalyst in the homopolymerization of ethylene or the copolymerization of ethylene with other monomers.

[0006] The technical solution of the present invention is as follows:

[0007] A metallocene complex having the structure shown in Formula I:

[0008]

[0009] In this case, R1 and R2 are substituents R1 and R2, which are independent of each other. a and R b Substituted phenyl, wherein R a and R b Halogen and C are independent of each other. 1-10 Alkyl, C 6-20 Aryl, or tertiary amines containing alkyl groups of 1-10 carbon atoms;

[0010] R3 and R4 are independent of each other and are C 6-20 Aryl, C 1-20 Alkyl-substituted C 6-20Aryl.

[0011] According to a preferred embodiment of the invention, R1 and R2 are substituents R1 and R2 independently of each other. a and R b Substituted phenyl, wherein R a and R b Halogen and C are independent of each other. 1-6 Alkyl, C 6-14 Aryl, or tertiary amines containing alkyl groups of 1-6 carbon atoms;

[0012] R3 and R4 are independent of each other and are C 6-14 Aryl, C 1-10 Alkyl-substituted C 6-20 Aryl.

[0013] According to another preferred embodiment of the invention, R1 and R2 are substituents R1 and R2 independently of each other. a and R b Substituted phenyl, wherein R a and R b They are halogens (e.g., F, Cl, or Br), methyl, ethyl, propyl, phenyl, or tertiary amines containing alkyl groups of 1-6 carbon atoms, and are independent of each other.

[0014] As an exemplary embodiment of the present invention, the metallocene complex represented by Formula I is at least one of the following compounds:

[0015]

[0016] Where X is Cl.

[0017] This invention also provides a method for preparing the above-mentioned metallocene complex, the method comprising the following steps:

[0018] The compound shown in Formula 1 was reacted with a Ti salt in the presence of alkyllithium to obtain the metallocene complex shown in Formula I.

[0019]

[0020] Among them, R1, R2, R3 and R4 have the definitions described above.

[0021] According to an embodiment of the present invention, the alkyl lithium is selected from at least one of butyl lithium (specifically, it may be n-butyl lithium, isobutyl lithium or tert-butyl lithium, preferably n-butyl lithium) or diisopropylamino lithium.

[0022] According to an embodiment of the present invention, the Ti salt can be a halide salt of Ti, such as titanium tetrachloride.

[0023] According to an embodiment of the present invention, the molar ratio of the compound shown in Formula 1, the Ti salt, and the alkyl lithium is 1:(1-1.5):(1-1.5), preferably 1:(1.1-1.4):(1.1-1.4).

[0024] According to an embodiment of the present invention, the reaction is carried out at room temperature for a time of 1 to 12 hours.

[0025] According to an embodiment of the present invention, the method for preparing the compound represented by Formula 1 is as follows:

[0026] (1) R1-Br and Mg were mixed in an organic solvent, and R2SiCl3 solution was added to the above reaction system. The mixture was reacted to obtain the compound shown in Formula 2 below.

[0027]

[0028] (2) The compound shown in Formula 3 and the compound shown in Formula 4 are mixed with Cu(CN)2 and alkyllithium in an organic solvent, and then the compound shown in Formula 2 is added to react to obtain the compound shown in Formula 1.

[0029]

[0030] Among them, R1, R2, R3 and R4 have the definitions described above.

[0031] According to an embodiment of the present invention, in step (1) or step (2), the organic solvent is selected from at least one of THF, acetonitrile, toluene, acetone, DMF, N-methylpyrrolidone, etc.

[0032] According to an embodiment of the present invention, in step (1), the molar ratio of R1-Br to Mg is 1:(1-3).

[0033] According to an embodiment of the present invention, in step (1), the molar ratio of R1-Br and R2SiCl3 is 1:(1-4).

[0034] According to an embodiment of the present invention, in step (1), the R2SiCl3 solution is R2SiCl3 dissolved in an organic solvent.

[0035] According to an embodiment of the present invention, in step (1), the reaction is carried out at room temperature for 1-12 hours. The content of the organic solvent is not particularly limited, as long as the raw materials are dissolved uniformly.

[0036] According to an embodiment of the present invention, step (1) specifically comprises:

[0037] First, R1-Br and Mg are mixed and reacted in an organic solvent at 20-90℃. Then, R2SiCl3 solution is added to the above reaction system at 0-10℃ and mixed and reacted to obtain the compound shown in Formula 2.

[0038] According to an embodiment of the present invention, in step (2), the molar ratio of the compound shown in Formula 3 and / or the compound shown in Formula 4 to Cu(CN)2 and alkyllithium is (18-24):1:(1-5).

[0039] According to an embodiment of the present invention, in step (2), the molar ratio of the compound represented by Formula 2 to Cu(CN)2 is (18-24):1.

[0040] According to an embodiment of the present invention, in step (2), the reaction is carried out at room temperature for a reaction time of 1 to 12 hours.

[0041] According to an embodiment of the present invention, step (2) specifically involves dissolving the compound shown in Formula 3 and / or the compound shown in Formula 4 with Cu(CN)2 in an organic solvent under an inert atmosphere, adding alkyl lithium at 0 to -60°C, and reacting at room temperature. After the reaction is completed, adding the compound shown in Formula 2 and continuing the reaction at room temperature to obtain the compound shown in Formula 1.

[0042] The present invention also provides the use of the metallocene complexes shown in Formula I as described above as catalysts for the homopolymerization of ethylene or the copolymerization of ethylene with other monomers.

[0043] According to an embodiment of the present invention, the other monomers are selected from at least one of α-olefins (excluding ethylene), cycloolefins, borneol and its derivatives.

[0044] For example, the other monomers are selected from at least one of propylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-heptene, 1-octene, 1-decene, 1-undecene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-eicosene, norbornene, norbornediene, ethylidene norbornene, phenyl norbornene, vinyl norbornene, dicyclopentadiene, 1,4-butadiene, 1,5-pentadiene, 1,6-hexadiene, styrene, α-methylstyrene, divinylbenzene, and 3-chloromethylstyrene.

[0045] The present invention also provides a catalyst composition for catalyzing the homopolymerization of ethylene or copolymerization with other monomers, the composition comprising a metallocene complex as shown in Formula I above and a cocatalyst.

[0046] According to an embodiment of the present invention, the co-catalyst is selected from at least one of trimethylaluminum, triethylaluminum, triisobutylaluminum, tripropylaluminum, tributylaluminum, dimethylaluminum chloride, triisopropylaluminum, trisec-butylaluminum, tricyclopentylaluminum, tripentylaluminum, triisopentylaluminum, trihexylaluminum, trioctylaluminum, ethyldimethylaluminum, methyldiethylaluminum, triphenylaluminum, tri-p-tolylaluminum, dimethylmethoxyaluminum, dimethylethoxyaluminum, trimethylboron, triethylboron, triisobutylboron, tripropylboron, and tributylboron.

[0047] According to an embodiment of the present invention, in the composition, the molar ratio of the metallocene complex represented by Formula I to the cocatalyst is 1:100-2500, for example 1:300, 1:500, 1:1000, 1:1500, 1:2000 or 1:2500.

[0048] According to an embodiment of the present invention, the reaction temperature for the catalyst composition to catalyze the homopolymerization of ethylene or copolymerization with other monomers is from 0°C to 150°C, for example from 50°C to 130°C, such as from 50°C to 120°C. For example, 50°C, 60°C, 70°C, 80°C, 90°C, 100°C, 110°C, or 120°C.

[0049] The beneficial effects of this invention are:

[0050] This invention provides a metallocene complex, its preparation method, and its applications. The metallocene complex, when combined with a cocatalyst (e.g., MAO), can significantly enhance the catalytic activity of polymers. Even at temperatures as high as 110°C, the complex of this invention still exhibits high catalytic activity. Detailed Implementation

[0051] The technical solution of the present invention will be further described in detail below with reference to specific embodiments. It should be understood that the following embodiments are merely illustrative and explanatory of the present invention, and should not be construed as limiting the scope of protection of the present invention. All technologies implemented based on the above content of the present invention are covered within the scope of protection intended by the present invention.

[0052] Unless otherwise stated, the raw materials and reagents used in the following examples are commercially available products or can be prepared by known methods.

[0053] The molecular weight of the polymer was tested using an Alliance GPC V2000 GPC analyzer.

[0054] In the following examples, M w M is the weight-average molecular weight of the polymer. n The number-average molecular weight of the polymer is obtained by GPC testing.

[0055] Example 1

[0056]

[0057] A method for preparing a compound as shown in Formula I-1 above:

[0058] (S1) Under an inert atmosphere, 1-chloro-4-bromobenzene (1 mol) and Mg (2 mol) were mixed and reacted in 50 mL THF at 60 °C. 2 mol of R2SiCl3 (R2 is 1-chlorophenyl) was dissolved in 50 mL THF and added to the above reaction system. The mixture was mixed and reacted at room temperature for 12 h. The reaction was monitored by TLC. After the reaction was completed, the mixture was concentrated under reduced pressure, extracted with ethyl acetate, washed with saturated brine, separated, and concentrated again under reduced pressure to obtain the compound shown in Formula 2.

[0059]

[0060] (S2) Under an inert atmosphere, 20 mol of the compound shown in Formula 3 (R3 is phenyl) and 1 mol of Cu(CN)2 were mixed in tetrahydrofuran. 1 mol of tetrahydrofuran solution of n-butyllithium was added at -20°C, and the reaction was carried out at room temperature for 12 h. After the reaction was completed, 20 mol of the compound shown in Formula 2 from step (S1) was added to react with the compound shown in Formula 1.

[0061] (S3) At -78℃, 1.2 mol of tetrahydrofuran solution (1.6 M) of n-butyllithium was added dropwise to a THF solution of 1 mol of the compound shown in Formula 1, and the mixture was heated to room temperature and reacted for 3 h. Then, 1.2 mol of titanium tetrachloride was added to the reaction solution, and the mixture was stirred at room temperature for 2 h. After the reaction was completed, water (20 mL) was added to quench the reaction. The solvent was removed by rotary evaporation, and 100 mL of solution was added to dissolve the compound. The solution was washed with saturated brine, concentrated, and purified by column chromatography (using petroleum ether and ethyl acetate as eluents) to obtain compound I-1.

[0062] The NMR analysis data for Equation I-1 are as follows: 1 H NMR (300MHz, DMSO-d6) δ7.65(m,2H),7.55-7.35(m,22H),3.22(s,2H),1.79(s,6H).

[0063] Example 2

[0064] The difference between Example 2 and Example 1 is that 1-chloro-4-bromobenzene in Example 1 is replaced with 1-methyl-4-bromobenzene, and R2SiCl3 (R2 is 1-chlorophenyl) is replaced with R2SiCl3 (R2 is 1-methyl-phenyl), and the reaction yields compound I-2.

[0065]

[0066] The NMR analysis data for Equation I-2 are as follows: 1 H NMR (300MHz, DMSO-d6) δ7.65(m,2H),7.50-7.35(m,18H),7.26(m,4H),3.22(s,4H),2.37(s,6H),1.79(s,6H).

[0067] Example 3

[0068] The difference between Example 3 and Example 1 is that 1-chloro-4-bromobenzene in Example 1 is replaced with 1-phenyl-4-bromobenzene, and R2SiCl3 (R2 is 1-chlorophenyl) is replaced with R2SiCl3 (R2 is 1-phenyl-phenyl), and the reaction yields compound I-3.

[0069]

[0070] The NMR analysis data for Equation I-3 are as follows: 1 H NMR (300MHz, DMSO-d6) δ7.87(m,4H),7.75(m,4H),7.65(m,6H),7.50-7.35(m,20H),3.22(s,4H),1.79(s,6H).

[0071] Comparative Example 1

[0072] The difference between Comparative Example 1 and Example 1 is that R2SiCl3 (R2 is 1-chlorophenyl) in step (S1) of Example 1 is replaced with R2SiCl3 (R2 is methyl) to prepare the compound shown in Formula A.

[0073]

[0074] Application examples

[0075] The complexes obtained in Examples 1-3 and Comparative Example 1 were used as catalysts to catalyze the polymerization of ethylene in the presence of a co-catalyst. The specific reaction steps are as follows:

[0076] The polymerization reaction was carried out in a 100 mL dry stainless steel autoclave, which was heated at 120 °C under vacuum for 30 minutes and then cooled to the reaction temperature under an ethylene atmosphere. Appropriate amounts of MAO (10 wt% toluene solution) and toluene were added to the reactor, followed by saturation with ethylene for 20 minutes. After reaching isothermal equilibrium, a toluene solution of catalyst was added to the reactor, and ethylene was introduced at the desired pressure to initiate polymerization. After stirring the reaction mixture to the desired reaction time, the ethylene pressure in the autoclave was slowly released, and then 15 mL of ethanol was added dropwise to terminate the polymerization. The resulting mixture was poured into 50 mL of 10% HCl ethanol solution. The resulting polymer product was collected by filtration, washed with 10% HCl ethanol solution, and then dried under vacuum at 65 °C for 10 hours to constant weight. The polymer mass was then weighed. The catalytic results of the complex are shown in Table 1.

[0077] Table 1 Results under co-catalysis with MAO co-catalyst

[0078]

[0079]

[0080] The embodiments of the present invention have been described above by way of example. However, the scope of protection of the present invention is not limited to the above embodiments. Any modifications, equivalent substitutions, improvements, etc., made by those skilled in the art within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A metallocene complex, characterized in that, It has the structure shown in Equation I:

2. The metallocene complex according to claim 1, characterized in that, R1 and R2 are substituents R1 and R2 independently of each other. a and R b Substituted phenyl, wherein R a and R b Halogen and C are independent of each other. 1-10 Alkyl, C 6-20 Aryl, or tertiary amines containing alkyl groups of 1-10 carbon atoms; R3 and R4 are independent of each other and are C 6-20 Aryl, C 1-20 Alkyl-substituted C 6-20 Aryl.

3. The metallocene complex according to claim 1, characterized in that, R1 and R2 are substituents R1 and R2 independently of each other. a and R b Substituted phenyl, wherein R a and R b Halogen and C are independent of each other. 1-6 Alkyl, C 6-14 Aryl, or tertiary amines containing alkyl groups of 1-6 carbon atoms; R3 and R4 are independent of each other and are C 6-14 Aryl, C 1-10 Alkyl-substituted C 6-20 Aryl.

4. The metallocene complex according to claim 1, characterized in that, The metallocene complex shown in Formula I is at least one of the following compounds:

5. The method for preparing the metallocene complex according to any one of claims 1-4, characterized in that, The method includes the following steps: The compound shown in Formula 1 was reacted with a Ti salt in the presence of alkyllithium to obtain the metallocene complex shown in Formula I. Among them, R1, R2, R3 and R4 have the definitions described above.

6. The method according to claim 5, characterized in that, The alkyl lithium is selected from at least one of butyl lithium or diisopropylamino lithium. Preferably, the molar ratio of the compound shown in Formula 1, the Ti salt, and the alkyllithium is 1:(1-1.5):(1-1.5).

7. The method according to claim 5, characterized in that, The preparation method of the compound represented by Formula 1 is as follows: (1) R1-Br and Mg were mixed in an organic solvent, and R2SiCl3 solution was added to the above reaction system. The mixture was reacted to obtain the compound shown in Formula 2 below. (2) The compound shown in Formula 3 and the compound shown in Formula 4 are mixed with Cu(CN)2 and alkyllithium in an organic solvent, and then the compound shown in Formula 2 is added to react to obtain the compound shown in Formula 1. Among them, R1, R2, R3 and R4 have the definitions described above.

8. Use of the metallocene complex according to any one of claims 1-4 as a catalyst for the homopolymerization of ethylene or the copolymerization of ethylene with other monomers.

9. A catalyst composition for catalyzing the homopolymerization of ethylene or its copolymerization with other monomers, characterized in that, The composition comprises the metallocene complex and cocatalyst as described in any one of claims 1-4. Preferably, the co-catalyst is selected from at least one of trimethylaluminum, triethylaluminum, triisobutylaluminum, tripropylaluminum, tributylaluminum, dimethylaluminum chloride, triisopropylaluminum, trisec-butylaluminum, tricyclopentylaluminum, tripentylaluminum, triisopentylaluminum, trihexylaluminum, trioctylaluminum, ethyldimethylaluminum, methyldiethylaluminum, triphenylaluminum, tri-p-tolylaluminum, dimethylmethoxyaluminum, dimethylethoxyaluminum, trimethylboron, triethylboron, triisobutylboron, tripropylboron, and tributylboron.

10. The composition according to claim 9, characterized in that, In the composition, the molar ratio of the metallocene complex of Formula I to the cocatalyst is 1:100-2500. Preferably, the reaction temperature for the catalyst composition to catalyze the homopolymerization of ethylene or copolymerization with other monomers is from 0°C to 150°C.

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