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 the following formula I. The metallocene complex is matched with a promoter (such as MAO), and the catalytic activity of a polymer can be remarkably improved. Even at the temperature of up to 160 DEG C, the complex provided by the invention still has relatively high catalytic activity. The alpha-olefin insertion rate is high, the insertion uniformity is good, and the molecular weight distribution of the product is narrow.

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] X indicates that it is selected from chlorine, bromine, or iodine;

[0010] R1 and R2 are selected from C1-C1, respectively. 10 Alkyl groups, or R1, R2, and the carbon atoms they are connected to, form a C4-C ring with one or more rings. 12 Alicyclic alkyl groups;

[0011] R3 is selected from hydrogen, and from straight-chain or branched C1-C atoms. 10 Alkyl, C3-C 12 Alicyclic alkyl groups, straight-chain or branched C2-C 12 alkenyl, C3-C12 Alicyclic alkenyl;

[0012] R4 and R5 are independently selected from hydrogen and C1-C, respectively. 10 alkyl;

[0013] R6 is a naphthyl or a substituted naphthyl group, wherein the substituent is C1-C. 10 Alkyl, halogen or C6-C 20 Aryl; A is C or Si;

[0014] All R7 groups are H, or two R7 groups are linked together to form a phenyl group.

[0015] According to an embodiment of the present invention, R1 and R2 are each selected from C1-C6 alkyl groups, or R1, R2 and the carbon atoms they are connected to together form a C4-C8 alicyclic alkyl group having one or more rings;

[0016] R3 is selected from hydrogen, straight-chain or branched C1-C6 alkyl, C3-C8 alicyclic alkyl, straight-chain or branched C2-C8 alkenyl, and C3-C8 alicyclic alkenyl.

[0017] R4 and R5 are independently selected from hydrogen and C1-C6 alkyl groups, respectively;

[0018] R6 is a naphthyl or a substituted naphthyl group, wherein the substituent is a C1-C6 alkyl, halogen, or C6-C6 alkyl group. 12 Aryl; A is C or Si;

[0019] All R7 groups are H, or two R7 groups are linked together to form a phenyl group.

[0020] As an exemplary embodiment of the present invention, the metallocene complex represented by Formula I is at least one of the following compounds:

[0021]

[0022]

[0023]

[0024] The present invention also provides a method for preparing the above-mentioned metallocene complex, the method comprising:

[0025] The compound shown in Formula II was reacted with a Zr salt in the presence of alkyllithium to give the metallocene complex shown in Formula I.

[0026]

[0027] Among them, R1, R2, R3, R4, R5, R6 and R7 have the definitions described above.

[0028] 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.

[0029] According to an embodiment of the present invention, the Zr salt can be a halide salt of Zr, such as zirconium tetrachloride.

[0030] According to an embodiment of the present invention, the molar ratio of the compound represented by Formula II, the Zr salt, and the alkyllithium is 1:(1-1.5):(1-1.5), preferably 1:(1.1-1.4):(1.1-1.4).

[0031] According to an embodiment of the present invention, the reaction is carried out at room temperature for a time of 1 to 12 hours.

[0032] According to an embodiment of the present invention, the method for preparing the compound represented by Formula II is as follows:

[0033] (1) The substituted cyclopentadiene shown in formula a is reacted with the compound shown in formula b in the presence of a base to produce the compound shown in formula c.

[0034] (2) The compound shown in formula c is reacted with the fluorene lithium shown in formula d to generate the compound shown in formula II;

[0035]

[0036]

[0037] According to an embodiment of the present invention, in step (1), the base is an alkyl alkali metal compound or an alkali metal salt of an alcohol; the alkali metal salt of the alcohol is selected from sodium methoxide, sodium ethoxide, potassium ethoxide and potassium tert-butoxide; it is also, for example, a C1-C4 alkyl lithium, or for example, methyl lithium, ethyl lithium and propyl lithium or butyl lithium.

[0038] According to an embodiment of the present invention, either step (1) or step (2) is carried out in the presence of an organic solvent, wherein the organic solvent is selected from one or more of tetrahydrofuran, diethyl ether, toluene, benzene, chloroform, dichloromethane and petroleum ether.

[0039] According to an embodiment of the present invention, in step (1), the molar ratio of the substituted cyclopentadiene shown in formula a to the compound shown in formula b is 1:1.0-1.4.

[0040] According to an embodiment of the present invention, step (1) is carried out at room temperature for a reaction time of 2 to 48 hours.

[0041] According to an embodiment of the present invention, in step (2), the molar ratio of the compound shown in formula c to the lithium fluorene shown in formula d is 1:1-2, and the reaction is carried out at 20-60 degrees Celsius for 2-48 hours.

[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 embodiments of the present invention, the reaction temperature for the catalyst composition to catalyze the homopolymerization of ethylene or its copolymerization with other monomers is from 0°C to 160°C, for example, from 50°C to 160°C, or from 50°C to 100°C. Examples include 50°C, 60°C, 70°C, 80°C, 90°C, 100°C, 110°C, 120°C, 130°C, 140°C, 150°C, or 160°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 co-catalyst (e.g., MAO), can significantly improve the catalytic activity of polymers. Even at temperatures as high as 160°C, the complex of this invention still exhibits high catalytic activity. Furthermore, it demonstrates a high α-olefin insertion rate, good insertion uniformity, and a narrow molecular weight distribution of the product. 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] Example 1

[0054]

[0055] A method for preparing a compound as shown in Formula I-1 above, comprising the following steps:

[0056] (S1) Under an inert atmosphere, 1 mol of the substituted cyclopentadiene shown in formula a (where R1, R2, and R3 are all methyl groups, and two R7 groups are linked to form a phenyl group) was dissolved in 50 mL of tetrahydrofuran. At 0 to -20 °C, a 1.2 mol tetrahydrofuran solution of n-butyllithium (1.6 M) was added dropwise to the above solution, and the mixture was stirred at room temperature for 24 h. At 0 to -20 °C, the compound shown in formula b was added to the above mixture, and the reaction was carried out at room temperature for 24 h. The reaction was monitored by TLC. After the reaction was completed, the tetrahydrofuran was removed by rotary evaporation. The mixture was separated, and the aqueous phase was extracted with dichloromethane. The organic phases were combined after extraction, dried with anhydrous MgSO4, and washed with methanol to obtain the compound shown in formula c.

[0057] (S2) Dissolve 2 mol of fluorene in 30 mL of anhydrous diethyl ether. Add 2 mol of n-butyllithium in n-hexane (2.56 mol / L) dropwise under ice bath conditions. After the addition is complete, stir the mixture at room temperature for 1 day to obtain lithium fluorene as shown in formula d. Dissolve 1 mol of the prepared lithium fluorene in 30 mL of anhydrous diethyl ether and react it with 1 mol of the compound shown in formula c from step (S1) at room temperature for 5 days. After the reaction is complete, separate the reaction mixture. Extract the aqueous phase with 60 mL of diethyl ether. Combine the extracted organic phases, dry them with anhydrous MgSO4, evaporate to dryness, and perform column chromatography using pure petroleum ether as the developing solvent to generate the compound shown in formula II.

[0058] (3) 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 II, and the temperature was raised to room temperature and the reaction was continued for 3 h. Then, 1.2 mol of zirconium tetrachloride was added to the reaction solution, and the reaction was stirred at room temperature for 3 h. After the reaction was completed, water (20 mL) was added to quench the reaction. The solvent was removed by rotary evaporation, 100 mL was added to dissolve the compound, and the solution was washed with saturated brine. After concentration, the solution was purified by column chromatography (petroleum ether and ethyl acetate were used as eluents) to obtain compound I-1.

[0059] The NMR analysis data for Equation I-1 are as follows: 1 H NMR(300MHz,DMSO-d6)δ7.96-7.80(m,9H),7.60-7.45(m,8H),7.38(m,2H),7.28(m,2H) ),6.44(m,1H),6.22-6.10(m,2H),5.66(m,1H),4.66(s,1H),3.58(m,1H),1.35(s,9H).

[0060] Example 2

[0061] The difference between Example 2 and Example 1 is that,

[0062] In step (S2), R6 in the compound shown in formula b is replaced with Compound I-2 was obtained.

[0063]

[0064] The NMR analysis data for Equation I-2 are as follows: 1H NMR(300MHz,DMSO-d6)δ7.95-7.90(m,3H),7.80-7.70(m,4H),7.55-7.50(m,6H),7.40-7.35(m,6H),7.28 (m,2H),6.44(m,1H),6.22-6.10(m,2H),5.66(m,1H),4.66(s,1H),3.58(m,1H),2.66(s,6H),1.35(s,9H).

[0065] Example 3

[0066] The difference between Example 3 and Example 1 is that,

[0067] In step (S2), R6 in the compound shown in formula b is replaced with Compound I-3 was obtained.

[0068]

[0069] The NMR analysis data for Equation I-3 are as follows: 1 H NMR(300MHz,DMSO-d6)δ7.95-7.80(m,7H),7.72(s,2H),7.55-7.50(m,4H),7.45-7.35(m,6H),7 .28(m,2H),6.44(m,1H),6.22-6.10(m,2H),5.66(m,1H),4.66(s,1H),3.58(m,1H),1.35(s,9H).

[0070] Example 4

[0071] The difference between Example 4 and Example 1 is that,

[0072] In step (S1), in the substituted cyclopentadiene shown in formula a, both R7 atoms are H, yielding compound I-4.

[0073]

[0074] The NMR analysis data for Equation I-4 are as follows: 1 H NMR(300MHz,DMSO-d6)δ7.96-7.80(m,8H),7.62(m,2H),7.55-7.40(m,8H),7.38 (m,2H),7.28(m,2H),6.22-6.10(m,2H),4.66(s,1H),2.90(m,2H),1.35(s,9H).

[0075] Example 5

[0076] The difference between Example 5 and Example 2 is that,

[0077] In step (S1), in the substituted cyclopentadiene shown in formula a, both R7 atoms are H, yielding compound I-5.

[0078]

[0079] The NMR analysis data for Formula I-5 are as follows: 1 H NMR(300MHz,DMSO-d6)δ7.90(m,2H),7.80-7.70(m,4H),7.55-7.50(m,6H),7.40-7.35(m, 6H),7.28(m,2H),6.22-6.10(m,2H),4.66(s,1H),2.90(m,2H),2.66(s,6H),1.35(s,9H).

[0080] Example 6

[0081] The difference between Example 6 and Example 3 is that,

[0082] In step (S1), in the substituted cyclopentadiene shown in formula a, both R7 atoms are H, yielding compound I-6.

[0083]

[0084] The NMR analysis data for Formula I-6 are as follows: 1 H NMR(300MHz,DMSO-d6)δ7.90-7.80(m,6H),7.72(s,2H),7.55-7.50(m,4H),7.45-7 .35(m,6H),7.28(m,2H),6.22-6.10(m,2H),4.66(s,1H),2.90(m,2H),1.35(s,9H).

[0085] Comparative Example 1

[0086] The difference between Comparative Example 1 and Example 1 is that,

[0087] In step (S2), R6 in the compound shown in formula b is replaced with phenyl to obtain compound A.

[0088] The molecular weight of the polymer was tested using an Alliance GPC V2000 GPC analyzer.

[0089] 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.

[0090] Test Example 1: Ethylene / 1-hexene polymerization reaction

[0091] Aggregation conditions:

[0092] Preparation of the catalyst system: The complexes obtained in the above examples and comparative examples were used as catalysts and dissolved in toluene to prepare a catalyst solution with a mass fraction of 10%; methylaluminoxane (MAO) was added to the above catalyst solution, wherein the molar ratio of catalyst to Al was 1:1000.

[0093] (1) Under a nitrogen atmosphere, add 20 mL of Isopar E solvent to a 350 mL polymerization reactor, then connect the reactor to the polymerization reaction device, use a vacuum pump to evacuate for more than 5 minutes to remove oxygen from the pipeline of the polymerization device, and adjust the temperature control device to make the reaction temperature 30℃.

[0094] (2) Inject the catalyst system containing 1 μmol of complex into the reaction apparatus, close the valve after injection and introduce 1-hexene comonomer into the reactor, then add hydrogen, and finally continuously introduce ethylene to keep the total polymerization pressure constant at 2.0 MPa, and react at the predetermined temperature for 1 h.

[0095] (3) Terminate the reaction, cool to room temperature, and test the yield and related properties of the polymer product, as shown in Table 1.

[0096] Table 1. Polymerization activity and related properties of Examples 1-6 and Comparative Example 1

[0097]

[0098] 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: X indicates that it is selected from chlorine, bromine, or iodine; R1 and R2 are selected from C1-C1, respectively. 10 Alkyl groups, or R1, R2, and the carbon atoms they are connected to, form a C4-C ring with one or more rings. 12 Alicyclic alkyl groups; R3 is selected from hydrogen, and from straight-chain or branched C1-C atoms. 10 Alkyl, C3-C 12 Alicyclic alkyl groups, straight-chain or branched C2-C 12 Alkenyl, C3-C 12 Alicyclic alkenyl; R4 and R5 are independently selected from hydrogen and C1-C, respectively. 10 alkyl; R6 is a naphthyl or a substituted naphthyl group, wherein the substituent is C1-C. 10 Alkyl, halogen or C6-C 20 Aryl; A is either C or Si; All R7 groups are H, or two R7 groups are linked together to form a phenyl group.

2. The metallocene complex according to claim 1, characterized in that, R1 and R2 are selected from C1-C6 alkyl groups, or R1, R2 and the carbon atoms they are connected to together form a C4-C8 alicyclic alkyl group having one or more rings; R3 is selected from hydrogen, straight-chain or branched C1-C6 alkyl, C3-C8 alicyclic alkyl, straight-chain or branched C2-C8 alkenyl, and C3-C8 alicyclic alkenyl. R4 and R5 are independently selected from hydrogen and C1-C6 alkyl groups, respectively; R6 is a naphthyl or a substituted naphthyl group, wherein the substituent is a C1-C6 alkyl, halogen, or C6-C6 alkyl group. 12 Aryl; A is either C or Si; All R7 groups are H, or two R7 groups are linked together to form a phenyl group.

3. 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:

4. The method for preparing the metallocene complex according to any one of claims 1-3, characterized in that, The method includes: The compound shown in Formula II was reacted with a Zr salt in the presence of alkyllithium to give the metallocene complex shown in Formula I. Among them, R1, R2, R3, R4, R5, R6 and R7 have the definitions described above.

5. The method according to claim 4, characterized in that, The molar ratio of the compound shown in Formula II, the Zr salt, and the alkyllithium is 1:(1-1.5):(1-1.5), preferably 1:(1.1-1.4):(1.1-1.4). Preferably, the reaction is carried out at room temperature for 1 to 12 hours.

6. The method according to claim 4, characterized in that, The preparation method of the compound represented by Formula II is as follows: (1) The substituted cyclopentadiene shown in formula a is reacted with the compound shown in formula b in the presence of a base to produce the compound shown in formula c. (2) The compound shown in formula c is reacted with the fluorene lithium shown in formula d to generate the compound shown in formula II; 7. Use of the metallocene complex according to any one of claims 1-3 as a catalyst for the homopolymerization of ethylene or the copolymerization of ethylene with other monomers. Preferably, the other monomers are selected from at least one of α-olefins (excluding ethylene), cycloolefins, borneol and their derivatives. Preferably, 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.

8. A catalyst composition for catalyzing the homopolymerization of ethylene or its copolymerization with other monomers, characterized in that, The composition comprises the metallocene complex of Formula I as described in any one of claims 1-3 and a cocatalyst.

9. The catalyst composition according to claim 8, characterized in that, 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 catalyst composition according to claim 8, 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 160°C.

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