Catalyst system for ethylene / alpha-olefin copolymerization reaction and application thereof

Abstract

The invention provides a catalyst system for ethylene / alpha-olefin copolymerization reaction and application of the catalyst system, and belongs to the technical field of metal organic compound synthesis and high polymer material synthesis. The catalyst system comprises a main catalyst transition metal compound a and an activator b, the transition metal compound a has a structure as shown in the following formula (I): # imgabs0 # formula (I), and the activating agent b is a compound containing a group IIIA metal. The catalyst system is used for ethylene / alpha-olefin copolymerization, and has the advantages of high catalytic activity, high molecular weight and high comonomer insertion rate.

Description

Technical Field

[0001] The present invention belongs to the fields of synthesis of metal organic compounds and synthesis of polymer materials, and particularly relates to a catalyst system for ethylene / α-olefin copolymerization reaction and its application. Background Art In recent years, with the development of the global economy, the applications of high-performance polyolefin materials such as ethylene / α-olefin copolymers have been continuously increasing, and their demand has been growing continuously. Metallocene catalysts have attracted extensive attention due to their high catalytic activity, uniform molecular weight distribution, controllable polymerization structure, etc., and have become an important development direction in the field of olefin polymerization.

[0002] Cp 2 ZrCl 2 As a typical metallocene complex, the central zirconium atom coordinates through two cyclopentadienyl ligands and two chlorine atoms to form a stable tetrahedral structure. When using Cp 2 ZrCl 2 alone, its catalytic activity is low and it is difficult to directly initiate olefin polymerization reaction. The introduction of methylaluminoxane effectively solves this problem, and the synergistic effect of the two makes the Cp 2 ZrCl 2 / MAO system show extremely high activity in the homopolymerization and copolymerization reactions of olefins such as ethylene and propylene, and can precisely control the molecular weight, stereoregularity and branching degree of the polymer by adjusting the ligand structure or reaction conditions. Now metallocene catalysts have been used industrially. Among bridged metallocene compounds, bridged metallocene compounds with cyclopentadiene and indenyl ligands have both advantages such as high temperature stability and good copolymerizability, and can be used for the copolymerization of ethylene and α-olefins. Therefore, the research on catalyst systems based on cyclopentadienyl with different substitution patterns to improve the activity of copolymerization reaction and the properties of polymers has received extensive attention from researchers. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a new catalyst system for ethylene / α-olefin copolymerization aiming at the deficiencies of the prior art, which finely adjusts the electronic properties and steric hindrance of the substituents of the catalyst ligand, and has the advantages of high catalytic activity, high molecular weight and high comonomer insertion rate.

[0004] The present invention provides a catalyst system for ethylene / α-olefin copolymerization reaction, comprising: ① A transition metal compound a, and the transition metal compound a has a structure shown in the following formula (I): Formula (I); Wherein, R 1 ~R 12identical or different, and are each independently selected from a hydrocarbyl group having 1 to 10 carbon atoms, an aryl group or a hydrogen atom; M is selected from transition metals of Group IVB, VB, VIB or VIII; ②Activator b, and the activator b is a compound containing a Group IIIA metal.

[0005] Further, the hydrocarbyl group is selected from C 1 -C 10 alkyl group; Preferably, the hydrocarbyl group is selected from methyl, ethyl, isopropyl or cyclopentyl; More preferably, the hydrocarbyl group is selected from methyl.

[0006] Further, the aryl group is selected from C 6 -C 10 aryl group and its derivatives; Preferably, the aryl group is selected from phenyl, substituted phenyl; the aryl derivatives are selected from naphthyl, substituted naphthyl or fluorenyl.

[0007] Further, the transition metal compound a is a compound containing titanium, zirconium, hafnium, molybdenum, tungsten, cobalt, tantalum, vanadium, iron, nickel or palladium; Preferably, the transition metal compound a is a compound containing titanium, zirconium or hafnium; More preferably, the transition metal compound a is a compound containing zirconium. Further, the activator includes at least one of an alkylaluminoxane, an alkylaluminum or an organoboron compound; Preferably, the alkylaluminum is selected from trialkylaluminum; more preferably, the alkylaluminum is selected from triisobutyl; Preferably, the alkylaluminoxane compound is selected from at least one of methylaluminoxane or ethylaluminoxane; Preferably, the organoboron compound is selected from trityl tetrakis(pentafluorophenyl)borate. Further, the molar ratio of the transition metal compound a to the activator b in the catalyst system is 1:10 to 1000. Preferably, the molar ratio of the transition metal compound a to the activator b in the catalyst system is 1:50 to 200.

[0008] The present invention also provides an application of the catalyst system as described above in the copolymerization reaction of ethylene / α-olefin.

[0009] Further, the temperature of the copolymerization reaction is 60 to 140 °C.

[0010] Further, the pressure of the copolymerization reaction is 0.5 to 5 MPa. The present invention has the following advantages: In the catalyst system proposed by the present invention, in transition metal compound a, compared with the common silicon-bridged structure, the electron-donating ability of the carbon-carbon single bond with an ethylidene bridge is relatively weak, resulting in a higher electron density of the metal active center, reducing the steric hindrance effect of the comonomer, making it easier to coordinate with the ethylene comonomer, accelerating the chain initiation and chain growth rates. Moreover, the rigid structure of the ethylidene bridge effectively restricts ligand rotation, reduces chain transfer reactions such as β-H elimination, prolongs the chain growth time, and is conducive to increasing the molecular weight and reducing chain branching.

[0011] The ethylidene bridge belongs to a flexible bridge, allowing a certain degree of ligand dynamic adjustment, which can regulate the random or alternating distribution of the comonomer, making its insertion more uniform and the molecular weight distribution narrower. The thermal stability of the ethylidene bridge is moderate (stable up to ~120 °C), which is suitable for solution polymerization and slurry polymerization processes.

[0012] Methyl is an electron-donating group. Introducing a methyl substituent at the 2-position of the indenyl ring increases the electron density of the indenyl ring, indirectly increasing the electron cloud density of the metal center, thereby enhancing the monomer coordination ability and reducing the insertion energy barrier, which can improve the catalytic activity and slightly increase the 1-octene insertion rate. Similarly, introducing a methyl group on the ethylidene bridge donates electrons to the bridge and the metal center, increasing the electron density of zirconium (Zr) and thus enhancing the ethylene insertion rate. The large steric hindrance substituents on the fluorene ring reduce the β-H elimination reaction rate through steric shielding, promoting chain growth to be dominant, which is conducive to increasing the molecular weight. At the same time, the homogeneity of chain transfer can narrow the molecular weight distribution.

[0013] In summary, the ethylidene-bridged indenyl zirconium metal catalyst system proposed by the present invention for ethylene / α-olefin copolymerization has the characteristics of high catalytic activity, good copolymerization performance, high molecular weight, narrow molecular weight distribution, and low polymerization cost. The catalyst has good high-temperature resistance performance and is especially suitable for catalyzing high-temperature solution copolymerization of ethylene / α-olefins. Detailed implementation mode

[0014] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in combination with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Without conflict, the embodiments in the present invention and the features in the embodiments can be combined with each other.

[0015] An embodiment of the present invention provides a catalyst system for ethylene / α-olefin copolymerization, including: ① A transition metal compound a, and the transition metal compound a has the structure shown in the following formula (I): Formula (I); Wherein, R 1 ~R 12Same or different, and are independently selected from a hydrocarbon group having 1 to 10 carbon atoms, an aryl group, or a hydrogen atom; M is selected from transition metals of Group IVB, VB, VIB, or VIII. ②Activator b, and the activator b is a compound containing a Group IIIA metal.

[0016] In one embodiment of the present invention, the hydrocarbon group is selected from C 1 -C 10 alkyl. In a preferred embodiment of the present invention, the hydrocarbon group is selected from methyl, ethyl, isopropyl, or cyclopentyl. More preferably, the hydrocarbon group is selected from methyl.

[0017] In a preferred embodiment of the present invention, R 3、 R 11、 R 12 are independently selected from methyl.

[0018] In one embodiment of the present invention, the aryl group is selected from C 6 -C 10 aryl and its derivatives. In a preferred embodiment of the present invention, the aryl group is selected from phenyl, substituted phenyl. The aryl derivatives are selected from naphthyl, substituted naphthyl, or fluorenyl.

[0019] In one embodiment of the present invention, the transition metal compound a is a compound containing titanium, zirconium, hafnium, molybdenum, tungsten, cobalt, tantalum, vanadium, iron, nickel, or palladium. Preferably, the transition metal compound a is a compound containing titanium, zirconium, or hafnium. More preferably, the transition metal compound a is a compound containing zirconium. In one embodiment of the present invention, the activator includes at least one of an alkylaluminoxane, an alkylaluminum, and an organoboron compound. Preferably, the alkylaluminum can be a trialkylaluminum, such as TEAL, triisobutylaluminum, tri-n-butylaluminum, tri-n-hexylaluminum, or tri-n-octylaluminum; more preferably, the alkylaluminum can be triisobutylaluminum (TIBA). The alkylaluminoxane compound can be selected from methylaluminoxane (MAO), ethylaluminoxane. The organoboron compound can be selected from trityl tetrakis(pentafluorophenyl)borate [Ph 3 C][B(C 6 F 5 ) 4 . In one embodiment of the present invention, the molar ratio of the transition metal compound a to the activator b in the catalytic system is 1:10 to 1000. Preferably, the molar ratio of the transition metal compound a to the activator b in the catalytic system is 1:50 to 200.

[0020] In one embodiment of the present invention, the preparation method of the transition metal compound a includes the following steps: Step 1: Prepare benzo[6]fulvene represented by formula (I-3) using 5-phenyl-1H-indene represented by formula (I-1) and ketone represented by formula (I-2), and prepare 3,5-substituted indene represented by formula (I-5) using benzo[6]fulvene represented by formula (I-3) and bromobenzene containing substituents represented by formula (I-4);

[0021] Among formula (I-1), formula (I-2), formula (I-3), formula (I-4) and formula (I-5), R 1 、R 2 、R 3 、R 4 、R 5 and R 6 have the same definitions as R in formula (I) of the present invention; Step 2: Prepare the compound represented by formula (I-8) using 6,6,9,9-tetramethyl-7,8,9,11-tetrahydro-6H-benzo[a]fluorene containing substituents represented by formula (I-6) and 2,2-disubstituted epoxyethane represented by formula (I-7). The compound represented by formula (I-8) is prepared into the compound represented by formula (I-9) through substitution with methanesulfonic acid, and the compound represented by formula (I-9) is prepared into the bromo-substituted compound represented by formula (I-10) through bromine substitution;

[0022] Among formula (I-6), formula (I-7), formula (I-8), formula (I-9) and formula (I-10), R 6 、R 7 、R 8 、R 9 、R 10 、R 11 and R 12 have the same definitions as R in formula (I) of the present invention; Step 3: Prepare the compound represented by formula (I-11) using benzo[6]fulvene represented by formula (I-5) and the bromo-substituted compound represented by formula (I-10);

[0023] In formula (I-11), R 1 、R 2 、R 3 、R 4 、R 5 、R 6 、R 7 、R 8 、R 9 、R 10 、R 11 and R 12 have the same definitions as R in formula (I) of the present invention; Step 4. Use the compound shown in formula (I-11) and MCl 4 to prepare the transition metal compound shown in formula (I); M is selected from transition metals in Group IVB, VB, VIB or VIII; wherein all the above reactions are carried out under nitrogen protection.

[0024] In a preferred embodiment of the present invention, Step 1 specifically includes the following sub-steps: Step 1.1. Dissolve 5-phenyl-1H-indene shown in formula (I-1) in tetrahydrofuran, cool to 5°C, add sodium methoxide, and stir at room temperature for 2 hours; Step 1.2. Add the ketone shown in formula (I-2) to the system and reflux for 12 hours; Step 1.3. Add dilute hydrochloric acid solution to the reaction system to terminate the reaction, add saturated sodium bicarbonate solution to remove the excessive dilute hydrochloric acid, extract three times, dehydrate with anhydrous sodium sulfate, and concentrate to obtain benzofulvene shown in (I-3); Step 1.4. Dissolve the substituted bromobenzene shown in formula (I-4) in THF, cool to 5°C, and dropwise add n-butyllithium solution while stirring, and react at room temperature for 18 hours; Step 1.5. Cool the above reaction system to 5°C, add a mixed solution of benzofulvene shown in formula (I-3) and diethyl ether, and react at room temperature for 12 hours; Step 1.6. Add dilute hydrochloric acid solution to the reaction system to terminate the reaction, add saturated sodium bicarbonate solution to remove the excessive dilute hydrochloric acid, extract three times, dehydrate with anhydrous sodium sulfate, and concentrate to obtain 3,5-substituted indene shown in formula (I-5).

[0025] Preferably, in Step 1, the molar ratio of 5-phenyl-1H-indene shown in formula (I-1) to the ketone shown in formula (I-2) is 1:(0.8 - 1.4), preferably 1:(1 - 1.2).

[0026] Preferably, the molar ratio of the substituted bromobenzene shown in formula (I-4) to n-butyllithium is 1:(0.8 - 1.4), preferably 1:(1 - 1.2).

[0027] Preferably, the molar ratio of benzofulvene shown in formula (I-3) to substituted phenyllithium shown in (I-4) is 1:(1 - 1.6), preferably 1:(1.2 - 1.4).

[0028] In a preferred embodiment of the present invention, Step 2 specifically includes the following sub-steps: Step 2.1. Dissolve the substituted 6,6,9,9-tetramethyl-7,8,9,11-tetrahydro-6H-benzofluorene shown in formula (I-6) in tetrahydrofuran, cool to 5°C, and dropwise add n-butyllithium solution while stirring, and react at room temperature for 2 hours; Step 2.2: Cool the above reaction system to -50°C with liquid nitrogen, slowly add dropwise 2,2-disubstituted ethylene oxide shown in formula (I-7), maintain the low temperature for 1 hour, and then react at room temperature for 6 hours; Step 2.3: Add saturated ammonium chloride solution to terminate the reaction, and perform column chromatography with silica gel to obtain the compound shown in formula (I-8); Step 2.4: Dissolve the compound shown in formula (I-8) in THF, add triethylamine, react for 1 hour, then cool to 5°C, and slowly add methanesulfonyl chloride and react for 12 hours; Step 2.5: Add dilute hydrochloric acid solution to the reaction system to terminate the reaction, add saturated sodium bicarbonate solution to remove the excessive dilute hydrochloric acid, extract three times with ether, remove water with anhydrous sodium sulfate, and concentrate to obtain the compound shown in formula (I-9); Step 2.6: Dissolve the compound shown in formula (I-9) in acetone, add lithium bromide, and heat to 50°C and react for 12 hours; Step 2.7: Add water to terminate the reaction, extract three times with ether, remove water with anhydrous sodium sulfate, filter, and perform column chromatography with silica gel to obtain the compound shown in formula (I-10).

[0029] Preferably, the molar ratio of the 6,6,9,9-tetramethyl-7,8,9,11-tetrahydro-6H-benzofluorene with substituents shown in formula (I-6) to n-butyllithium is 1:(0.8 - 1.4), preferably 1:(1 - 1.2).

[0030] Preferably, the molar ratio of the 6,6,9,9-tetramethyl-7,8,9,11-tetrahydro-6H-benzofluorene with substituents shown in formula (I-6) to the 2,2-disubstituted ethylene oxide shown in formula (I-7) is 1:(0.6 - 1.2), preferably 1:(0.8 - 1.0).

[0031] Preferably, the molar ratio of the compound shown in formula (I-8) to triethylamine is 1:(1.8 - 2.4), preferably 1:(2 - 2.2).

[0032] Preferably, the molar ratio of the compound shown in formula (I-9) to lithium bromide is 1:(2.0 - 2.8), preferably 1:(2.2 - 2.6).

[0033] In a preferred embodiment of the present invention, Step 3 specifically includes the following sub-steps: Step 3.1: Dissolve 3,5-substituted indene shown in formula (I-5) in petroleum ether, cool to 5°C, add dropwise n-butyllithium solution while stirring, and react at room temperature for 12 hours; Step 3.2: Add dropwise the ether solution of the bromo-substituted compound shown in formula (I-10) to the above reaction system and react at room temperature for 12 hours; Step 3.3: Add saturated ammonium chloride solution to terminate the reaction, and then obtain the compound shown in formula (I-11) through extraction, drying, and concentration processes.

[0034] Preferably, the molar ratio of the 3,5-disubstituted indene shown in formula (I-5) to n-butyllithium is 1:(1.8 - 2.4), and preferably 1:(2 - 2.2).

[0035] Preferably, the molar ratio of the 3,5-disubstituted indene shown in formula (I-5) to the bromo-substituted compound shown in formula (I-10) is 1:(0.8 - 1.4), and preferably 1:(1 - 1.2).

[0036] In a preferred embodiment of the present invention, Step 4 specifically includes the following sub-steps: Step 4.1: Add the compound shown in formula (I-11) to diethyl ether, cool it to -5°C, and dropwise add n-butyllithium solution while stirring, and react at room temperature for 12 hours; Step 4.2: Cool the above system to -50°C, and add MCl 4 to the system, and naturally restore to room temperature and react for 24 hours; Step 4.3: The reaction product is subjected to filtration, washing, dissolution, filtration, and concentration processes to obtain the transition metal compound shown in formula (I).

[0037] Preferably, the molar ratio of the compound shown in formula (I-11) to n-butyllithium is 1:(1.8 - 2.6), and preferably 1:(2 - 2.4).

[0038] Preferably, the molar ratio of the compound shown in formula (I-11) to MCl 4 is 1:(0.6 - 1.4), and preferably 1:(0.8 - 1.0).

[0039] An embodiment of the present invention also provides the application of the above catalyst system in the copolymerization reaction of ethylene / α-olefin.

[0040] In an embodiment of the present invention, the temperature of the ethylene / α-olefin copolymerization reaction is 60 - 140°C.

[0041] In an embodiment of the present invention, the pressure of the copolymerization reaction is 0.5 - 5 MPa. In an embodiment of the present invention, the ethylene / α-olefin copolymerization reaction is carried out in a gas phase or slurry process form, and low-carbon alkanes, aromatic hydrocarbons, and ionic liquids are used as reaction solvents in the process. Preferably, the low-carbon alkanes include at least one of toluene and n-hexane.

[0042] Specifically, an embodiment of the present invention further provides a method for ethylene / α-olefin copolymerization, including the copolymerization of ethylene / α-olefin carried out in the presence of any of the above catalyst systems. That is, the reaction method adopted in the above application.

[0043] In an embodiment of the present invention, the reaction method includes the following steps: the ethylene / α-olefin copolymerization reaction is carried out in a batch or continuous manner; the high-pressure reaction kettle is replaced with nitrogen and ethylene 2-5 times respectively, and in an ethylene atmosphere, a solvent, 1-octene, and a catalyst are added, and the reaction is carried out at 60-140 °C and a pressure of 0.5-3 MPa; after the reaction is completed, the temperature is lowered and the pressure is released, and the copolymer product is obtained after washing, filtering, and drying.

[0044] In an embodiment of the present invention, the solvent includes at least one of aromatic hydrocarbons, ethers, and alkanes; more preferably, the organic solvent includes at least one of toluene, tetrahydrofuran, diethyl ether, and n-hexane.

[0045] The present invention will be elaborated in detail below with reference to embodiments.

[0046] Example 1 The preparation method of the transition metal compound a (CH 3 ) 2 C 2 H 2 (C 24 H 20 )(C 17 H 22 )ZrCl 2 in the catalyst system for ethylene / α-olefin copolymerization includes the following steps: All reactions are carried out under nitrogen protection;

[0047] Step 1: Synthesis of 1-phenyl-3-(1-methyl-1-phenylethyl)indene All reactions are carried out under nitrogen protection.

[0048]

[0049] Add 1-phenyl-5H-indene (0.6 g, 3.12 mmol) to a bottom flask, add 30 mL of tetrahydrofuran, stir until completely dissolved, cool to 5 °C in an ice-water bath, and then add sodium methoxide (0.20 g, 3.77 mmol) to this solution. The solution gradually turns brownish-yellow and is stirred at room temperature for 2 hours. Add dimethyl ketone (0.21 g, 3.77 mmol) and reflux for 12 hours. Add dilute hydrochloric acid solution to stop the reaction in the reaction system, add saturated sodium bicarbonate solution to remove the excess dilute hydrochloric acid, extract three times with saturated brine and n-hexane, collect the upper organic phase, dry with anhydrous sodium sulfate, filter and concentrate to obtain the crude product. Wash the crude product with ice methanol to obtain orange-red powder 1-phenyl-6,6-dimethylbenzofulvene (0.62 g, 2.65 mmol), with a yield of 84.9%.

[0050]

[0051] Add bromobenzene (1.66 g, 10.0 mmol) to a bottom flask, add 40 mL of THF until completely dissolved, cool to 5 °C in an ice-water bath, and dropwise add a 2.4 M solution of n-butyllithium (5.0 mL, 12.0 mmol) while stirring. React for 18 hours, and white precipitate will precipitate. Filter and wash twice with ether, and dry under vacuum. Obtain phenyllithium (0.71 g, 8.5 mmol) with a yield of 84.2%. Add phenyllithium (0.29 g, 3.5 mmol) to a bottom flask, add 30 mL of ether, stir until completely dissolved, add a mixed solution of 1-phenyl-6,6-dimethylbenzofulvene (0.62 g, 2.65 mmol) and 20 mL of ether, react at room temperature for 12 hours, add dilute hydrochloric acid solution to stop the reaction in the reaction system, add saturated sodium bicarbonate solution to remove the excess dilute hydrochloric acid, separate and extract three times with saturated brine and ether, collect the upper organic phase, dry with anhydrous sodium sulfate, filter and concentrate to obtain the product yellow powder 1-phenyl-3-(1-methyl-1-phenylethyl)indene (1.12 g, 3.61 mmol), with a yield of 85.9%.

[0052] 1 H NMR (400 MHz, CDCl 3 , 298K) 7.60 (d, 2H), 7.47 (dd, J = 3.1, 1.8 Hz,1H), 7.47 – 7.35 (m, 2H), 7.31 (dd, J = 7.6, 6.3 Hz, 1H), 7.31 – 7.20 (m, 1H),7.23 – 7.17 (m, 1H), 6.31 (t, J= 4.1 Hz, 1H), 3.10 (d, J = 4.2 Hz, 1H). Step 2: Synthesis of 11-(2,2-dimethyl-2-bromoethyl)(6,6,9,9-tetramethyl-7,8,9,11-tetrahydro-6H-benzofluorene) All reactions were carried out under nitrogen protection.

[0053]

[0054] Add 6,6,9,9-tetramethyl-7,8,9,11-tetrahydro-6H-benzofluorene (1.5 g, 5.42 mmol) to a round-bottom flask, add 30 mL of tetrahydrofuran, stir until completely dissolved, cool to 5 °C in an ice-water bath, and dropwise add a 2.4 M solution of n-butyllithium (2.5 mL, 6.0 mmol) with stirring. React for 2 hours. Cool to -50 °C with liquid nitrogen, slowly dropwise add 2,2-dimethyloxirane (0.32 g, 4.36 mmol), and react for 6 hours after returning to room temperature naturally. Add saturated ammonium chloride solution to the reaction system to terminate the reaction, extract three times with saturated brine and ether by liquid separation, collect the upper organic phase, dry with anhydrous sodium sulfate, filter, and concentrate to obtain the crude product. Perform column chromatography on silica gel with 200 - 300 mesh. First, use ether as the eluent to remove the excess 6,6,9,9-tetramethyl-7,8,9,11-tetrahydro-6H-benzofluorene, and then elute through the column with an eluent of ether:ethyl acetate = 10:1 to obtain the white crystal 1,1-dimethyl-2-[11-(6,6,9,9-tetramethyl-7,8,9,11-tetrahydro-6H-benzofluorenyl)]ethanol (1.38 g, 3.84 mmol), with a yield of 88.2%.

[0055]

[0056] Dissolve the above white crystals (1.0 g, 2.78 mmol) in 30 mL of THF, stir until completely dissolved, add triethylamine (0.56 g, 5.56 mmol), after dissolution, add methanesulfonyl chloride (0.80 g, 5.56 mmol), and react for 12 hours. Add water to the reaction system to terminate the reaction, extract three times with n-hexane, collect the organic phase, dry it with anhydrous sodium sulfate, filter, and concentrate to obtain a yellow oily product. After dissolving it with 30 mL of acetone, add lithium bromide (0.48 g, 5.56 mmol), heat up to 50 °C, and react for 12 hours. Add dilute hydrochloric acid solution to the reaction system to terminate the reaction, add saturated sodium bicarbonate solution to remove the excess dilute hydrochloric acid, perform liquid-liquid extraction three times with saturated brine and diethyl ether, collect the organic phase, dry it with anhydrous sodium sulfate, and filter. Perform column chromatography on silica gel with 200 - 300 mesh using petroleum ether as the eluent to obtain a white solid (1.03 g, 2.52 mmol), with a yield of 90.6%.

[0057] 1 H NMR (400 MHz, CDCl 3 , 298K) 7.74 - 7.69 (m, 1H), 7.68 (s, 1H), 7.60 - 7.52 (m, 1H), 7.46 - 7.37 (m, 2H), 7.34 (s, 1H), 5.71 - 5.65 (m, 1H), 2.41(dd, J = 14.5, 6.2 Hz, 1H), 2.15 (dd, J = 14.5, 6.0 Hz, 1H), 1.87 - 1.76 (m, 7H),1.69 - 1.58 (m, 2H), 1.33 (s, 6H), 1.28 (s, 4H). Step 3: Synthesis of 1-(11-fluorenyl)-2,2-dimethyl-2-{[3-(1-methyl-1-phenylethyl)]indenyl}ethane All reactions were carried out under nitrogen protection.

[0058]

[0059] Add indene (0.56 g, 1.81 mmol) to a round-bottom flask, add 30 mL of petroleum ether, stir until completely dissolved, cool to 5 °C in an ice-water bath, and dropwise add a 2.4 mol / L solution of n-butyllithium (1.51 mL, 3.62 mmol). Stir at room temperature for 12 hours, and a yellow precipitate will form. After the reaction is completed, filter, wash the precipitate three times with petroleum ether, and dry it under vacuum to obtain a light yellow precipitate. Dissolve the light yellow precipitate in 30 mL of ether, add a mixed solution of a bromo-substituted compound (0.74 g, 1.81 mmol) and ether to it. The solution turns orange-red, react at room temperature for 12 hours, add saturated ammonium chloride solution to the reaction system to terminate the reaction, perform liquid-liquid extraction three times with saturated brine and ether, collect the upper organic phase, dry it with anhydrous sodium sulfate, filter and concentrate to obtain the crude product, wash it three times with ice-cold n-hexane, and dry it under vacuum for 2 hours to obtain an orange powder ligand (1.03 g, 1.61 mmol), with a yield of 88.9%.

[0060] 1 H NMR (400 MHz, CDCl 3 , 298K) 7.76 - 7.70 (m, 1H), 7.68 (s, 1H), 7.60(t, J = 1.7 Hz, 1H), 7.61 - 7.53 (m, 2H), 7.53 - 7.35 (m, 9H), 7.34 - 7.27 (m,2H), 7.27 - 7.21 (m, 1H), 7.24 - 7.17 (m, 2H), 6.37 (d, J = 6.9 Hz, 1H), 5.66 -5.60 (m, 1H), 3.21 - 3.15 (m, 1H), 2.22 - 2.09 (m, 2H), 1.87 - 1.76 (m, 2H),1.69 (s, 2H), 1.64 (s, 3H), 1.68 - 1.58 (m, 2H), 1.33 (s, 6H), 1.28 (s, 5H),1.14 (d, J = 1.6 Hz, 3H), 1.09 (d, J = 1.4 Hz, 3H). Step 4: (CH 3 ) 2 C 2 H 2 (C 24 H 20 )(C 17 H 22 )ZrCl 2Synthesis All reactions were carried out under nitrogen protection.

[0061]

[0062] Add the ligand (0.8 g, 1.25 mmol) to a round-bottom flask, add 30 mL of diethyl ether, stir to dissolve, then cool to -5 °C, and add dropwise a 2.4 mol / L n-butyllithium solution (1.05 mL, 2.51 mmol). The solution turns red and yellow precipitate precipitates. React at room temperature for 12 hours, cool the system to -50 °C, add zirconium tetrachloride (0.23 g, 1.0 mmol), and gradually warm it to room temperature and stir to react for 24 hours. Let it stand and filter to obtain a red precipitate. The precipitate is dissolved in dichloromethane, the solution is filtered and then concentrated to obtain a red powder, washed three times with diethyl ether, and dried in vacuo to obtain the product (CH 3 ) 2 C 2 H 2 (C 24 H 20 )(C 17 H 22 )ZrCl 2 (0.22 g, 0.27 mmol), with a yield of 21.9%.

[0063] 1 H NMR (400 MHz, CDCl 3 , 298K) 7.63 (dd, J J = 7.7, 1.6 Hz, 1H), 7.61 -7.56 (m, 2H), 7.59 - 7.35 (m, 11H), 7.34 - 7.16 (m, 6H), 6.34 (d, J J = 6.8 Hz,1H), 5.59 - 5.52 (m, 1H), 3.21 - 3.15 (m, 1H), 2.98 - 2.88 (m, 1H), 2.18 (d, J J = 6.0 Hz, 2H), 1.89 - 1.78 (m, 2H), 1.73 - 1.64 (m, 7H), 1.67 - 1.59 (m, 1H),1.29 (s, 2H), 1.19 (d, J J = 5.9 Hz, 3H), 1.11 (d, J J = 1.4 Hz, 3H), 1.05 (d, J J = 1.4Hz, 3H).

[0064] The structures of all the products obtained from the experiments were verified to be correct by NMR spectra.

[0065] Example 2 Preparation method of transition metal compound a in the catalyst system for ethylene / α-olefin copolymerization Same as Example 1, except that in the catalyst preparation step 1, 2,2-diethyloxirane was used to replace 2,2-dimethyloxirane, and the resulting catalyst was (CH 3 CH 2 ) 2 C 2 H 2 (C 24 H 20 )(C 17 H 22 )ZrCl 2 。

[0066] The NMR results are as follows: 1 H NMR (400 MHz, CDCl 3 , 298K) 7.75 – 7.69 (m, 1H), 7.66 – 7.60 (m,3H), 7.59 – 7.17 (m, 14H), 6.40 (d, J = 6.9 Hz, 1H), 5.64 (td, J = 6.5, 0.9 Hz,1H), 3.24 (d, J = 6.9 Hz, 1H), 2.30 (dd, J = 13.5, 6.2 Hz, 1H), 2.22 (dd, J = 13.6,6.2 Hz, 1H), 1.86 – 1.77 (m, 2H), 1.69 (s, 3H), 1.74 – 1.64 (m, 1H), 1.67 –1.58 (m, 1H), 1.61 – 1.55 (m, 1H), 1.58 – 1.52 (m, 2H), 1.55 – 1.48 (m, 1H),1.33 (d, J = 4.5 Hz, 9H), 1.28 (s, 2H), 0.77 (dt, J = 18.0, 6.4 Hz, 6H). Example 3 Preparation method of transition metal compound a in the catalyst system for ethylene / α-olefin copolymerization Same as Example 1, except that hafnium tetrachloride was used to replace zirconium tetrachloride in Step 4 of the catalyst preparation, and the resulting catalyst was (CH 3 ) 2 C 2 H 2 (C 24 H 20 )(C 17 H 22 )H f Cl 2 .

[0067] The NMR results are as follows: 1 H NMR (400 MHz, CDCl 3 , 298K) 7.76 – 7.69 (m, 1H), 7.67 (s, 1H), 7.63– 7.55 (m, 2H), 7.58 – 7.52 (m, 2H), 7.50 (d, J = 2.0 Hz, 1H), 7.48 – 7.40 (m,5H), 7.40 (d, J = 0.8 Hz, 1H), 7.35 – 7.27 (m, 3H), 7.27 – 7.18 (m, 2H), 7.18 –7.13 (m, 1H), 6.42 (d, J = 7.0 Hz, 1H), 5.67 (t, J = 6.2 Hz, 1H), 3.19 (dd, J =7.0, 0.7 Hz, 1H), 2.29 – 2.18 (m, 2H), 1.89 – 1.76 (m, 2H), 1.73 – 1.65 (m,3H), 1.68 – 1.60 (m, 1H), 1.53 (ddt, J = 13.2, 10.7, 6.6 Hz, 3H), 1.50 – 1.41(m, 1H), 1.33 (s, 2H), 1.28 (d, J = 0.8 Hz, 6H), 0.75 (t, J = 6.4 Hz, 5H). Example 4 Preparation method of transition metal compound a in the catalyst system for ethylene / α-olefin copolymerization Same as Example 1, except that in the catalyst preparation step 1, 5-phenyl-2-methyl-1H-indene was used to replace 5-phenyl-1H-indene, and the obtained catalyst was (CH 3 ) 2 C 2 H 2 (C 25 H 22 )(C 17 H 22 )ZrCl 2 .

[0068] The NMR results are as follows: 1 H NMR (400 MHz, CDCl 3 , 298K) 7.76 – 7.70 (m, 1H), 7.68 (s, 1H), 7.62(dddd, J = 9.4, 5.0, 2.0, 1.2 Hz, 2H), 7.58 – 7.52 (m, 1H), 7.49 – 7.38 (m,6H), 7.38 – 7.16 (m, 7H), 6.24 (d, J = 6.8 Hz, 1H), 5.61 (t, J = 6.1 Hz, 1H),3.14 (dq, J = 6.9, 1.6 Hz, 1H), 2.22 (dd, J = 13.4, 6.0 Hz, 1H), 2.14 (dd, J =13.3, 6.1 Hz, 1H), 1.89 (ddd, J = 12.1, 8.3, 5.4 Hz, 1H), 1.85 – 1.77 (m, 1H),1.77 – 1.69 (m, 1H), 1.69 (s, 3H), 1.69 – 1.61 (m, 1H), 1.64 (s, 3H), 1.33(s, 6H), 1.28 (s, 2H), 1.23 (s, 2H), 1.16 (d, J = 1.4 Hz, 3H), 1.09 (d, J = 1.6Hz, 3H). Example 5 Preparation method of transition metal compound a in the catalyst system for ethylene / α-olefin copolymerization Same as Example 2, except that hafnium tetrachloride was used to replace zirconium tetrachloride in Step 4 of the catalyst preparation, and the resulting catalyst was (CH 3 CH 2 ) 2 C 2 H 2 (C 24 H 20 )(C 17 H 22 )H f Cl 2 。

[0069] The NMR results are as follows: 1 H NMR (400 MHz, CDCl 3 , 298K) 7.76 – 7.69 (m, 1H), 7.67 (s, 1H), 7.63– 7.55 (m, 2H), 7.58 – 7.52 (m, 2H), 7.50 (d, J = 2.0 Hz, 1H), 7.48 – 7.40 (m,5H), 7.40 (d, J = 0.8 Hz, 1H), 7.35 – 7.27 (m, 3H), 7.27 – 7.18 (m, 2H), 7.18 –7.13 (m, 1H), 6.92 (d, J = 7.0 Hz, 1H), 5.17 (t, J = 6.2 Hz, 1H), 3.79 (dd, J =7.0, 0.7 Hz, 1H), 2.19 – 2.18 (m, 2H), 1.89 – 1.76 (m, 2H), 1.73 – 1.65 (m,3H), 1.68 – 1.60 (m, 1H), 1.53 (ddt, J = 13.2, 10.7, 6.6 Hz, 3H), 1.50 – 1.41(m, 1H), 1.33 (s, 2H), 1.28 (d, J = 0.8 Hz, 6H), 0.75 (t, J = 6.4 Hz, 5H). Example 6 Preparation method of transition metal compound a in the catalyst system for ethylene / α-olefin copolymerization Same as Example 1, except that in step 2 of catalyst preparation, ethylene oxide was used to replace 2,2-dimethyloxirane, and the resulting catalyst was C 2 H 4 (C 24 H 20 )(C 17 H 22 )ZrCl 2 。

[0070] The NMR results are as follows: 1H NMR (400 MHz, CDCl 3 , 298K) 7.71 – 7.69 (m, 1H), 7.58 (s, 1H), 7.53– 7.57 (m, 2H), 7.50 – 7.43 (m, 1H), 7.41 (d, J = 2.3 Hz, 1H), 7.37 – 7.32 (m,3H), 7.31 – 7.28 (m, 3H), 7.30 – 7.26 (m, 2H), 7.25 (s, 1H), 7.24 – 7.17 (m,2H), 7.14 – 7.06 (m, 3H), 6.59 (d, J = 6.6 Hz, 1H), 4.89 – 4.83 (m, 1H), 3.33 –3.26 (m, 1H), 2.20 – 2.10 (m, 1H), 2.13 – 1.93 (m, 2H), 1.96 – 1.89 (m, 1H),1.92 – 1.87 (m, 1H), 1.89 – 1.82 (m, 1H), 1.85 – 1.76 (m, 1H), 1.69 (s, 3H),1.68 – 1.59 (m, 2H), 1.33 (s, 6H), 1.25 (d, J = 17.0 Hz, 5H). Example 7 Preparation method of transition metal compound a in the catalyst system for ethylene / α-olefin copolymerization Same as Example 1, except that in step 2 of catalyst preparation, 3-tert-butyl-6,6,9,9-tetramethyl-7,8,9,11-tetrahydro-6H-benzofluorene was used, and the resulting catalyst was (CH 3 ) 2 C 2 H 2 (C 24 H 20 )(C 25H 30 )ZrCl 2 。

[0071] The NMR results are as follows: 1 H NMR (400 MHz, CDCl 3 , 298K) 7.80 – 7.72 (m, 2H), 7.69 – 7.62 (m,2H), 7.62 – 7.57 (m, 1H), 7.53 – 7.48 (m, 2H), 7.48 – 7.41 (m, 2H), 7.44 –7.35 (m, 3H), 7.34 – 7.27 (m, 2H), 7.27 – 7.17 (m, 3H), 6.32 (d, J = 6.7 Hz,1H), 5.47 (td, J = 5.9, 0.8 Hz, 1H), 3.21 – 3.15 (m, 1H), 2.22 (dd, J = 13.4, 6.0Hz, 1H), 2.14 (dd, J = 13.3, 6.1 Hz, 1H), 1.87 – 1.76 (m, 2H), 1.69 (s, 2H),1.64 (s, 3H), 1.68 – 1.59 (m, 2H), 1.37 (s, 5H), 1.33 (d, J = 3.3 Hz, 6H), 1.28(d, J = 0.8 Hz, 8H), 1.14 (d, J = 1.6 Hz, 3H), 1.09 (d, J = 1.4 Hz, 3H). Application Example 1 The ethylene and α-olefin copolymerization reaction includes the following steps: Heat a 100 mL high-pressure reactor to 140 °C, displace it five times with nitrogen and ethylene respectively, cool it to 50 °C, add 30 mL of n-hexane, 7 mL of 1-octene, and 1 mL of a toluene solution of triisobutylaluminum (the aluminum element content is 200 μmol) under an ethylene atmosphere, stir and mix for 1 min, and then add 1 mL of a toluene solution of borate [Ph 3 C][B(C 6 F 5 ) 4 (the boron element content is 2 μmol), and 2 μmol of the transition metal compound obtained in Example 1.

[0072] Ethylene was introduced and the ethylene pressure was maintained at 2 MPa, and the temperature was raised to 120 °C. The reaction was carried out for 10 min. The reaction was terminated with acidified ethanol with a volume ratio of hydrochloric acid / ethanol of 1:9. The copolymer was filtered and dried to obtain a copolymer product, and the polymerization activity was 1.85×10 7 g (mol·h) -1 , the molar content of octene in the copolymer product was 11.2 mol%, M W =23.3×10 4 , PDI = 2.34.

[0073] Application Example 2 Ethylene and α-olefin copolymerization reaction Same as Application Example 1, except that the transition metal compound obtained in Example 2 was used for the ethylene and α-olefin copolymerization reaction, and the obtained polymerization activity was 1.65×10 7 g (mol·h) -1 , the molar content of octene in the copolymer product was 8.9 mol%, M W =19.4×10 4 , PDI = 2.13.

[0074] Application Example 3 Ethylene and α-olefin copolymerization reaction Same as Application Example 1, except that the transition metal compound obtained in Example 3 was used for the ethylene and α-olefin copolymerization reaction, and the polymer activity was 2.15×10 6 g (mol·h) -1 , the molar content of octene in the copolymer product was 9.2 mol%, M W =16.8×10 4 , PDI = 2.03. Application Example 4 Ethylene and α-olefin copolymerization reaction Same as Application Example 1, except that the transition metal compound obtained in Example 4 was used for the ethylene and α-olefin copolymerization reaction, and the polymer activity was 1.97×10 7 g (mol·h) -1 , the molar content of octene in the copolymer product was 14.7 mol%, M W =17.7×10 4 , PDI = 2.28.

[0075] Application Example 5 Ethylene and α-olefin copolymerization reaction Same as Application Example 1, except that the transition metal compound obtained in Example 5 was used for the ethylene and α-olefin copolymerization reaction, and the polymer activity was 1.91×10 6 g (mol·h)-1 , the molar content of octene in the copolymerization product is 9.4 mol%, M W = 12.4×10 4 , PDI = 2.35.

[0076] Application Example 6 Ethylene and α-olefin copolymerization reaction Same as Application Example 1, except that the transition metal compound obtained in Example 6 is used for the ethylene and α-olefin copolymerization reaction, and the polymer activity is 1.35×10 7 (mol·h) -1 , the molar content of octene in the copolymerization product is 10.7 mol%, M W = 19.9×10 4 , PDI = 2.32.

[0077] Application Example 7 Ethylene and α-olefin copolymerization reaction Same as Application Example 1, except that the transition metal compound obtained in Example 7 is used for the ethylene and α-olefin copolymerization reaction, and the polymer activity is 1.89×10 7 (mol·h) -1 , the molar content of octene in the copolymerization product is 11.8 mol%, M W = 25.4×10 4 , PDI = 2.14.

[0078] Application Example 8 Ethylene and α-olefin copolymerization reaction Same as Application Example 1, except that the polymerization reaction pressure is 5 MPa; The obtained polymerization activity is 1.94×10 7 g (mol·h) -1 , the molar content of octene in the copolymerization product is 9.4 mol%, M W = 13.3×10 4 , PDI = 2.21.

[0079] Application Example 9 Ethylene and α-olefin copolymerization reaction Same as Application Example 1, except that the polymerization reaction pressure is 2.5 Mpa; The obtained polymerization activity is 2.01×10 7 g (mol·h) -1 , the molar content of octene in the copolymerization product is 11.2 mol%, M W = 14.6×10 4 , PDI = 2.23. The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims

1. A catalyst system for ethylene / α-olefin copolymerization, characterized in that: include: ① A transition metal compound a, wherein the transition metal compound a has a structure shown in the following formula (I): Formula (I); Among them, R1~R 12 are the same or different and are independently selected from a hydrocarbon group, an aryl group or a hydrogen atom having 1 to 10 carbon atoms; M is selected from a transition metal of Group IVB, VB, VIB or Group VIII; ② Activator b, activator b is a compound containing a Group IIIA metal.

2. The catalyst system according to claim 1, characterized in that The hydrocarbon group is selected from C1-C 10 The alkyl group; Preferably, the hydrocarbon group is selected from methyl, ethyl, isopropyl or cyclopentyl; More preferably, the hydrocarbon group is selected from methyl.

3. The catalyst system according to claim 1, characterized in that The aryl group is selected from C6-C 10 Aryl and its derivatives; Preferably, the aryl group is selected from phenyl and substituted phenyl; the aryl derivative is selected from naphthyl, substituted naphthyl or fluorenyl.

4. The catalyst system according to claim 1, characterized in that The transition metal compound a is a compound containing titanium, zirconium, hafnium, molybdenum, tungsten, cobalt, tantalum, vanadium, iron, nickel or palladium; Preferably, the transition metal compound a is a compound containing titanium, zirconium or hafnium; More preferably, the transition metal compound a is a zirconium-containing compound.

5. The catalyst system according to claim 1, characterized in that The activator comprises at least one of alkylaluminoxane, alkylaluminum or organic boron compound; Preferably, the alkylaluminum is selected from trialkylaluminum; more preferably, the alkylaluminum is selected from triisobutyl; Preferably, the alkylaluminoxane compound is selected from at least one of methylaluminoxane or ethylaluminoxane; Preferably, the organic boron compound is selected from trityltetrakis(pentafluorophenyl)boric acid.

6. The catalyst system according to claim 1, characterized in that The molar ratio of the transition metal compound a to the activator b in the catalytic system is 1:10-1000.

7. Preferably, the molar ratio of transition metal compound a to activator b in the catalyst system is 1:50-200.

8. Use of the catalyst system according to any one of claims 1 to 6 in ethylene / α-olefin copolymerization.

9. The use according to claim 7, characterized in that: The temperature of the copolymerization reaction is 60~140℃.

10. The use according to claim 7, characterized in that: The pressure of the copolymerization reaction is 0.5~5 MPa.

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