CN116410237A - Synthesis method of non-bridged symmetrical metallocene catalyst, product and application thereof - Google Patents

Abstract

The invention discloses a synthesis method of a non-bridged symmetrical metallocene catalyst, a product and application thereof, wherein the method takes fourth subgroup metal chloride, a C1-C3 alkyl metal reagent and cyclopentadiene derivatives as raw materials to react in an organic solvent under the environment of nitrogen or argon. The invention has the advantages of few reaction steps, simple and convenient operation, high efficiency, strong substrate applicability and the like.

Description

Synthetic method of non-bridged symmetrical metallocene catalyst and its product and application

technical field

The invention relates to a synthesis method of a non-bridged symmetrical metallocene catalyst, a product and an application thereof.

Background technique

Metallocene compounds generally refer to a class of organic complexes composed of transition metals or rare earth metals and at least one cyclopentadiene or its derivatives as ligands. Two identical rings coordinate with the central metal atom to form a sandwich structure, which is the so-called non-bridged symmetrical double metallocene catalyst, such as: Cp ₂ MCl ₂ , (Ind) ₂ MCl ₂ (M is titanium, zirconium, hafnium ; Cp is cyclopentadienyl; Ind is indenyl).

Currently, there are two approaches for the efficient synthesis of unbridged symmetric metallocene catalysts. Method 1: react cyclopentadiene derivatives with strong basic compounds to generate cyclopentadiene ligand salts, and then react the ligand salts with transition metal halides or their complexes to prepare catalysts; method 2: first React cyclopentadiene derivatives with strong basic compounds to generate cyclopentadiene ligand salts, then react with trimethylchlorosilane to obtain trimethylsilyl cyclopentadiene derivatives, and finally react with transition metal halides The reaction produces the target product.

Although the above method can effectively prepare non-bridged symmetrical metallocene catalysts, it has the disadvantages of many reaction steps and cumbersome operation. Due to the poor solubility of cyclopentadiene derivative ligand salts or transition metal halides in organic solvents, solid feeding or slurry feeding is often required during the reaction, and the reaction needs to be carried out under anhydrous and oxygen-free conditions. This further increases the difficulty and safety risks of the response operation.

In 2001, Eisch et al. (Organometallics 2001, 20, 4132-4134.) reported a new method for preparing non-bridged symmetrical metallocene compounds. The method adopts a one-pot two-step method, first reacting 2 equivalents of n-butyl lithium with zirconium tetrachloride to obtain dibutyl zirconium dichloride, and then reacting with 2 equivalents of cyclopentadiene to obtain bis(cyclopentadiene Alkenyl) zirconium dichloride, the yield is greater than 95%. Compared with traditional methods, this process has the advantages of less reaction steps, simple operation, and low safety risk. However, in our application of this method for the synthesis of symmetrical metallocene compounds, we found that although this process can effectively prepare bis(cyclopentadienyl) zirconium dichloride, bis(indenyl) zirconium dichloride, bis(formyl) Cyclopentadienyl) zirconium dichloride, but for the preparation of bis(pentamethylcyclopentadienyl) titanium dichloride, bis(2-phenylindenyl) zirconium dichloride, bis(1-methyl Indenyl) zirconium dichloride, bis(trimethylsilylcyclopentadienyl) zirconium dichloride, bis(pentamethylcyclopentadienyl) zirconium dichloride or bis(pentamethylcyclopentadienyl) zirconium dichloride For non-bridged symmetrical metallocene compounds such as dienyl) hafnium dichloride, the reaction results are relatively poor, and the yield is only 20-35%.

Contents of the invention

In order to at least partly solve the technical deficiencies in the prior art, the inventors made the present invention.

As an aspect of the present invention, it relates to a method for preparing a non-bridged symmetrical metallocene catalyst, using the fourth subgroup metal chloride, C1-C3 alkyl metal reagent and cyclopentadiene derivative as raw materials, under nitrogen or Under an argon atmosphere and in an organic solvent, a non-bridged symmetric metallocene catalyst is obtained through a one-pot two-step reaction.

Specifically, the method for preparing a non-bridged symmetrical metallocene catalyst comprises:

(1) At a certain feed temperature, 2 equivalents of C1-C3 alkyl metal reagents are added to the mixture of the fourth subgroup metal chloride and the organic solvent, and react at room temperature to obtain the mixture;

(2) At a certain feed temperature, add 2 equivalents of cyclopentadiene derivatives to the mixture obtained in step (1), and react at a certain reaction temperature.

In a specific embodiment, the general formula of the fourth subgroup metal chloride is MCl ₄ , wherein M is an element titanium, zirconium, hafnium.

In a specific embodiment, the C1-C3 alkyl metal reagent is RLi, R ₂ Zn or RMgX; wherein, R is a C1-C3 normal alkyl group, and X is a halogen chlorine, bromine or iodine.

In a specific embodiment, the cyclopentadiene derivative can be selected from the following compounds:

Wherein, R ¹ is C2-C4 carbon chain alkyl, benzyl, trimethylsilyl; n is an integer of 2-5; when R ³ is hydrogen, R ² can be C1-C4 carbon chain alkyl , benzyl, trimethylsilyl; when R ² is hydrogen, R ³ can be C1-C4 carbon chain alkyl, benzyl, phenyl, 4-methylphenyl, 4-methoxyphenyl ; R ² and R ³ can be methyl, ethyl at the same time; R ⁴ can be hydrogen, methyl, phenyl.

In a specific embodiment, the certain feed temperature is -78 to 0 degrees Celsius, preferably -40 to -10 degrees Celsius; the certain reaction temperature is 25 to 140 degrees Celsius, preferably 60 to 110 degrees Celsius.

In a specific embodiment, the organic solvent is n-hexane, n-heptane, toluene, o-xylene, tetrahydrofuran, 2-methyltetrahydrofuran, diethyl ether or ethylene glycol dimethyl ether.

In a specific embodiment, the reaction time of step (1) is 4-8 hours; the reaction time of step (2) is 5-10 hours.

As another aspect of the present invention, it relates to the non-bridged symmetrical metallocene catalyst prepared by the above method.

As another aspect of the present invention, it relates to the application of the above-mentioned non-bridged symmetrical metallocene catalyst in olefin polymerization.

As another aspect of the present invention, it relates to olefin polymerization, using the non-bridged symmetrical metallocene catalyst described in claim 10. Specifically, the olefin polymerization reaction is 1-decene polymerization reaction.

The bis-n-butyl dichloride metal intermediate obtained during the reaction is not stable and is easily decomposed into a dichloro metal compound, which cannot continue to react with the cyclopentadiene derivative to obtain the target product. When using multi-substituted cyclopentadiene derivatives or trimethylsilyl cyclopentadiene derivatives for the preparation of symmetrical metallocene compounds, due to the electronic effect and steric hindrance effect of the substituents, the cyclopentadiene The reactivity of derivatives, when the reactivity of cyclopentadiene derivatives is low, the probability of side reactions will increase, and dichlorometal compounds will be obtained, resulting in the failure of target reactions and low product yields.

Through the exploration of the reaction process, we found that when C1-C3 alkyl metal reagents such as methyllithium, ethyllithium, methylmagnesium chloride, ethylmagnesium chloride, propylmagnesium chloride or diethylzinc are used for the reaction, dialkyl The stability of the metal intermediate reduces the probability of side reactions, thereby improving the yield of the target product non-bridged symmetrical metallocene compound, and expanding the scope of substrate application of the original method.

The invention uses the fourth subgroup metal chlorides, C1-C3 alkyl metal reagents and cyclopentadiene derivatives as raw materials to prepare non-bridging symmetric The metallocene catalyst has the advantages of fewer reaction steps, simple operation, high efficiency, and strong substrate applicability.

Detailed ways

Embodiments of the present invention will be described in detail below in conjunction with examples, but those skilled in the art will understand that the following examples are only used to illustrate the present invention, and should not be considered as limiting the scope of the present invention. Those who do not indicate the specific conditions in the examples are carried out according to the conventional conditions or the conditions suggested by the manufacturer. Reagents or instruments or method guides used in the examples of the present invention are not indicated to provide sources, all are commercially available conventional products or can be obtained from the applicant.

Summary of the invention:

The present invention adopts one-pot two-step reaction, under the environment of nitrogen or argon, in the organic solvent, the first step reaction: first add 2 equivalents of C1-C3 alkyl metal reagent (RM') into the fourth step at a certain feeding temperature In the mixture of subgroup metal chloride and solvent, and react at room temperature to obtain the double alkyl metal intermediate; the second step reaction: the double alkyl metal intermediate does not need to be separated and purified. Add 2 equivalents of cyclopentadiene derivatives (Cp'H), and react at a certain reaction temperature to obtain a non-bridged symmetrical metallocene catalyst; the synthetic route is shown in the following reaction formula:

The preferred technical scheme of the present invention to solve the problem:

In a specific embodiment, the general formula of the fourth subgroup metal chloride is MCl ₄ , wherein M is the element titanium, zirconium or hafnium.

In a specific embodiment, the alkyl metal reagent (RM') is alkyllithium (RLi), dialkylzinc (R ₂ Zn ), alkylmagnesium halide (RMgX); wherein, R is the normal structure of C1-C3 Alkyl, X is halogen chlorine, bromine or iodine.

In a specific embodiment, the cyclopentadiene derivative (Cp'H) is monosubstituted cyclopentadiene, polymethyl substituted cyclopentadiene, polysubstituted indene or fluorene, and the structural formula is as follows:

Wherein, R ¹ is C2-C4 carbon chain alkyl, benzyl, trimethylsilyl; n is an integer of 2-5; when R ³ is hydrogen, R ² can be C1-C4 carbon chain alkyl , benzyl, trimethylsilyl; when R ² is hydrogen, R ³ can be C1-C4 carbon chain alkyl, benzyl, phenyl, 4-methylphenyl, 4-methoxyphenyl ; R ² and R ³ can be methyl, ethyl at the same time; R ⁴ can be hydrogen, methyl, phenyl.

In a specific embodiment, the feeding temperature is -78 to 0 degrees Celsius, preferably -40 to -10 degrees Celsius; the reaction temperature is 25 to 140 degrees Celsius, preferably 60 to 110 degrees Celsius.

In a specific embodiment, the organic solvent is n-hexane, n-heptane, toluene, o-xylene, tetrahydrofuran, 2-methyltetrahydrofuran, diethyl ether or ethylene glycol dimethyl ether.

In a specific embodiment, the reaction time of the first step is 4-8 hours; the reaction time of the second step is 5-10 hours.

Example 1

The first step reaction: under nitrogen atmosphere, zirconium tetrachloride (2.33g, 10mmol) was added to toluene (80mL), and at -78 degrees Celsius (addition temperature), methyllithium/2-methyltetrahydrofuran solution was added (1.0mol/L) (20mL), the reaction system was warmed up to room temperature (25 degrees Celsius), and continued to stir for 4 hours to obtain a dialkyl metal intermediate. The second step reaction: the dialkyl metal intermediate was not separated, and pentamethylcyclopentadiene (2.72 g, 20 mmol) was added to the mixture at -78 degrees Celsius (feeding temperature). After the addition, the reaction system was warmed up to room temperature (25 degrees Celsius), and then heated to 110 degrees Celsius (reaction temperature) to continue the reaction for 10 hours. After the reaction, cool to room temperature and perform post-processing operations: filtration, vacuum distillation, recrystallization, and vacuum drying to obtain a light yellow powdery solid, which is the target product bis(pentamethylcyclopentadienyl)zirconium dichloride 1a (3.67 g, 85% yield).

Example 2

The reaction steps and operations are the same as in Example 1, except that the gas environment is argon. The reaction was stopped, and the target product 1a (3.76 g, yield 87%) was obtained after post-treatment.

Example 3

The reaction steps and operations are the same as in Example 1, except that the reaction solvent is o-xylene. The reaction was stopped, and the target product 1a (3.61 g, yield 84%) was obtained after post-processing.

Example 4

The reaction steps and operations are the same as in Example 1, except that the reaction solvent is n-heptane, and the reaction temperature is 98 degrees Celsius. The reaction was stopped, and the target product 1a (3.76 g, yield 87%) was obtained after post-treatment.

Example 5

The reaction steps and operations are the same as in Example 1, except that the reaction solvent is n-hexane, and the reaction temperature is 69 degrees Celsius. The reaction was stopped, and the target product 1a (3.33 g, yield 77%) was obtained after post-processing.

Example 6

The reaction steps and operations are the same as in Example 1, except that the reaction solvent is tetrahydrofuran, and the reaction temperature is 66 degrees Celsius. The reaction was stopped, and the target product 1a (3.24 g, yield 75%) was obtained after post-processing.

Example 7

The reaction steps and operations are the same as in Example 1, except that the reaction solvent is diethyl ether, and the reaction temperature is 25 degrees Celsius. The reaction was stopped, and the target product 1a (1.86 g, yield 43%) was obtained after post-processing.

Example 8

The reaction steps and operations are the same as those in Example 1, except that the reaction time of the first step is 8 hours. The reaction was stopped, and the target product 1a (3.80 g, yield 88%) was obtained after post-processing.

Example 9

The reaction steps and operation are the same as in Example 1, except that the second step reaction time is 5 hours. The reaction was stopped, and the target product 1a (2.72 g, yield 63%) was obtained after post-processing.

Example 10

The reaction steps and operations are the same as in Example 8, except that the second step reaction time is 5 hours. The reaction was stopped, and the target product 1a (2.94 g, yield 68%) was obtained after post-processing.

Example 11

The reaction steps and operations are the same as in Example 1, except that the feeding temperature is -40 degrees Celsius. The reaction was stopped, and the target product 1a (3.54 g, yield 82%) was obtained after post-processing.

Example 12

The reaction steps and operations are the same as those in Example 1, except that the feeding temperature is -10 degrees Celsius. The reaction was stopped, and the target product 1a (3.19 g, yield 74%) was obtained after post-processing.

Example 13

The reaction steps and operations are the same as in Example 1, except that the feeding temperature is 0 degrees Celsius. The reaction was stopped, and the target product 1a (2.82 g, yield 65%) was obtained after post-treatment.

Example 14

The reaction steps and operations are the same as in Example 1, except that the reaction temperature is 25 degrees Celsius. The reaction was stopped, and the target product 1a (1.73 g, yield 40%) was obtained after post-processing.

Example 15

The reaction steps and operations are the same as in Example 1, except that the reaction temperature is 60 degrees Celsius. The reaction was stopped, and the target product 1a (3.07 g, yield 71%) was obtained after post-processing.

Example 16

The reaction steps and operations are the same as in Example 1, except that the reaction solvent is o-xylene, and the reaction temperature is 140 degrees Celsius. The reaction was stopped, and the target product 1a (3.73 g, yield 86%) was obtained after post-processing.

Example 17

The reaction steps and operations are the same as in Example 1, except that the metal alkyl reagent is dimethyl zinc/n-hexane solution (1.0 mol/L) (20 mL). The reaction was stopped, and the target product 1a (3.76 g, yield 87%) was obtained after post-treatment.

Example 18

The reaction steps and operations are the same as in Example 1, except that the metal alkyl reagent is ethyl lithium/cyclohexane solution (0.5 mol/L) (40 mL). The reaction was stopped, and the target product 1a (3.16 g, yield 73%) was obtained after post-processing.

Example 19

The reaction steps and operations are the same as in Example 1, except that the alkyl metal reagent is diethylzinc/n-hexane solution (1.0 mol/L) (20 mL). The reaction was stopped, and the target product 1a (3.02 g, yield 70%) was obtained after post-processing.

Example 20

The reaction steps and operations are the same as in Example 1, except that the metal alkyl reagent is n-propyllithium/n-hexane solution (1.0 mol/L) (20 mL). The reaction was stopped, and the target product 1a (2.73 g, yield 63%) was obtained after post-processing.

Example 21

The reaction steps and operations were the same as in Example 1, except that the metal alkyl reagent was methylmagnesium iodide/ether solution (3.0 mol/L) (6.68 mL). The reaction was stopped, and the target product 1a (3.58 g, yield 83%) was obtained after post-processing.

Example 22

The reaction steps and operations were the same as in Example 1, except that the alkyl metal reagent was a methylmagnesium chloride/tetrahydrofuran solution (3.0 mol/L) (6.68 mL). The reaction was stopped, and the target product 1a (3.72 g, yield 86%) was obtained after post-processing.

Example 23

The reaction steps and operations were the same as in Example 1, except that the alkyl metal reagent was a methylmagnesium bromide/tetrahydrofuran solution (3.0 mol/L) (6.68 mL). The reaction was stopped, and the target product 1a (3.50 g, yield 81%) was obtained after post-processing.

Example 24

The reaction steps and operations were the same as in Example 1, except that the metal alkyl reagent was ethylmagnesium bromide/tetrahydrofuran solution (1.0 mol/L) (20 mL). The reaction was stopped, and the target product 1a (3.02 g, yield 70%) was obtained after post-processing.

Example 25

The reaction steps and operations are the same as in Example 1, except that the metal alkyl reagent is n-propylmagnesium chloride/ether solution (2.0 mol/L) (10 mL). The reaction was stopped, and the target product 1a (2.68 g, yield 62%) was obtained after post-treatment.

Example 26

The reaction steps and operations are the same as in Example 1, except that the fourth subgroup metal chloride is titanium tetrachloride (1.90 g, 10 mmol). The reaction was stopped, and the target product 1b (2.49 g, yield 64%) was obtained after post-processing.

Example 27

The reaction steps and operations are the same as in Example 1, except that the fourth subgroup metal chloride is hafnium tetrachloride (3.20 g, 10 mmol). The reaction was stopped, and the target product 1c (3.80 g, yield 73%) was obtained after post-processing.

Example 28

The reaction steps and operations are the same as in Example 1, except that the cyclopentadiene derivative (Cp'H) is 5-trimethylsilylcyclopentadiene (2.76 g, 20 mmol). The reaction was stopped, and the target product 1d (3.84 g, yield 88%) was obtained after post-processing.

Example 29

The reaction steps and operations are the same as in Example 1, except that the cyclopentadiene derivative (Cp'H) is 5-n-butylcyclopentadiene (2.44 g, 20 mmol). The reaction was stopped, and the target product 1e (3.03 g, yield 75%) was obtained after post-processing.

Example 30

The reaction steps and operations are the same as in Example 1, except that the cyclopentadiene derivative (Cp'H) is 5-benzylcyclopentadiene (3.12 g, 20 mmol). The reaction was stopped, and the target product 1f (3.44 g, yield 73%) was obtained after post-processing.

Example 31

The reaction steps and operations are the same as in Example 1, except that the difference from Example 1 is that the cyclopentadiene derivative (Cp'H) is 1,2-dimethyl-1,3-cyclopentadiene (1.88g, 20mmol). The reaction was stopped, and the target product 1g (3.03g, yield 87%) was obtained after post-processing.

Example 32

The reaction steps and operations are the same as in Example 1, except that the cyclopentadiene derivative (Cp'H) is 1,3-dimethyl-1,3-cyclopentadiene (1.88g, 20mmol). The reaction was stopped, and the target product 1h (3.06 g, yield 88%) was obtained after post-processing.

Example 33

The reaction steps and operations are the same as in Example 1, except that the cyclopentadiene derivative (Cp'H) is fluorene (3.32 g, 20 mmol). The reaction was stopped, and the target product 1i (2.95 g, yield 60%) was obtained after post-processing.

Example 34

The reaction steps and operations are the same as in Example 1, except that the cyclopentadiene derivative (Cp'H) is 2-phenylindene (3.84 g, 20 mmol). The reaction was stopped, and the target product 1j (3.92 g, yield 72%) was obtained after post-processing.

Example 35

The reaction steps and operations are the same as in Example 1, except that the cyclopentadiene derivative (Cp'H) is 1-methylindene (2.60 g, 20 mmol). The reaction was stopped, and the target product 1k (2.94 g, yield 70%) was obtained after post-processing.

Example 36

The reaction steps and operations are the same as in Example 1, except that the cyclopentadiene derivative (Cp'H) is 1-trimethylsilylindene (3.77 g, 20 mmol). The reaction was stopped, and the target product 1l (3.87 g, yield 72%) was obtained after post-processing.

Example 37

The reaction steps and operation are the same as in Example 1, and the difference from Example 1 is that the cyclopentadiene derivative (Cp'H) is 1,2,3-trimethyl-1,3-cyclopentadiene (2.16 g, 20mmol). The reaction was stopped, and the target product 1m (3.12 g, yield 83%) was obtained after post-processing.

Example 38

The reaction steps and operation are the same as in Example 1, and the difference from Example 1 is that the cyclopentadiene derivative (Cp'H) is 1,2,4-trimethyl-1,3-cyclopentadiene (2.16 g, 20mmol). The reaction was stopped, and the target product 1n (3.20 g, yield 85%) was obtained after post-processing.

Example 39

The reaction steps and operation are the same as in Example 1, and the difference from Example 1 is that the cyclopentadiene derivative (Cp'H) is 1,2,3,4-tetramethyl-1,3-cyclopentadiene (2.44g, 20mmol). The reaction was stopped, and the target product 1o (3.60 g, yield 89%) was obtained after post-processing.

Example 40

The reaction steps and operations are the same as in Example 1, except that the cyclopentadiene derivative (Cp'H) is 5-ethylcyclopentadiene (1.88 g, 20 mmol). The reaction was stopped, and the target product 1p (2.51 g, yield 72%) was obtained after post-processing.

Example 41

The reaction steps and operations are the same as in Example 1, except that the cyclopentadiene derivative (Cp'H) is 1-n-butylindene (3.44 g, 20 mmol). The reaction was stopped, and the target product 1q (3.58 g, yield 71%) was obtained after post-processing.

Example 42

The reaction steps and operations are the same as in Example 1, except that the cyclopentadiene derivative (Cp'H) is 1-benzylindene (4.12 g, 20 mmol). The reaction was stopped, and the target product 1r (3.90 g, yield 68%) was obtained after post-processing.

Example 43

The reaction steps and operations are the same as in Example 1, except that the cyclopentadiene derivative (Cp'H) is 2-n-butylindene (3.44 g, 20 mmol). The reaction was stopped, and the target product 1s (3.28 g, yield 65%) was obtained after post-processing.

Example 44

The reaction steps and operations are the same as in Example 1, except that the cyclopentadiene derivative (Cp'H) is 2-benzylindene (4.12 g, 20 mmol). The reaction was stopped, and the target product 1t (4.01 g, yield 70%) was obtained after post-processing.

Example 45

The reaction steps and operations are the same as in Example 1, except that the cyclopentadiene derivative (Cp'H) is 2-(4-methoxyphenyl)indene (4.44g, 20mmol). The reaction was stopped, and the target product 1u (4.54 g, yield 75%) was obtained after post-processing.

Example 46

The reaction steps and operations are the same as in Example 1, except that the cyclopentadiene derivative (Cp'H) is 2-(4-methylphenyl)indene (4.12g, 20mmol). The reaction was stopped, and the target product lv (4.13 g, yield 72%) was obtained after post-processing.

Example 47

The reaction steps and operations are the same as in Example 1, except that the cyclopentadiene derivative (Cp'H) is 1,2-dimethylindene (2.88 g, 20 mmol). The reaction was stopped, and the target product 1w (2.92 g, yield 65%) was obtained after post-processing.

Example 48

The reaction steps and operations are the same as in Example 1, except that the cyclopentadiene derivative (Cp'H) is 1,2,5-trimethylindene (3.16 g, 20 mmol). The reaction was stopped, and the target product 1x (3.57 g, yield 75%) was obtained after post-processing.

Example 49

The reaction steps and operations are the same as in Example 1, except that the cyclopentadiene derivative (Cp'H) is 1,2-dimethyl-5-phenylindene (4.41 g, 20 mmol). The reaction was stopped, and the target product 1y (3.67g, yield 61%) was obtained after post-processing.

Example 50

The reaction steps and operations are the same as in Example 1, except that the cyclopentadiene derivative (Cp'H) is cyclopentadiene (1.32 g, 20 mmol). The reaction was stopped, and the target product 1z (2.81 g, yield 96%) was obtained after post-processing.

Example 51

The reaction steps and operations are the same as in Example 1, except that the cyclopentadiene derivative (Cp'H) is indene (2.32 g, 20 mmol). The reaction was stopped, and the target product 1aa (2.76 g, yield 70%) was obtained after post-processing.

Example 52

The reaction steps and operations are the same as in Example 5, except that the cyclopentadiene derivative (Cp'H) is indene (2.32 g, 20 mmol). The reaction was stopped, and the target product 1aa (3.36 g, yield 86%) was obtained after post-processing.

Comparative example 1

The method described in the literature (Organometallics 2001, 20, 4132-4134.) was used to prepare bis(pentamethylcyclopentadienyl)zirconium dichloride 1a. Reaction steps: In the first step of reaction, under nitrogen atmosphere, zirconium tetrachloride (2.33g, 10mmol) was added in toluene (80mL), and at -78 degrees Celsius, n-butyllithium/n-hexane solution (2.5mol /L) (8mL), the system slowly returned to 20 degrees Celsius after 8 hours. In the second step reaction, the reaction system was cooled to -78 degrees Celsius again, and pentamethylcyclopentadiene (3.40 g, 25 mmol) was added to the mixture. After the addition, the reaction system continued to stir and react at -78 degrees Celsius for 1 hour, then returned to room temperature and raised the temperature to 110 degrees Celsius, and continued to stir and react for 4 hours. After the reaction, cool to room temperature and perform post-processing operations: filtration, vacuum distillation, recrystallization, and vacuum drying to obtain a light yellow powdery solid, which is the target product, bis(pentamethylcyclopentadienyl) dichloride Zirconium 1a (0.86 g, 20% yield).

Comparative example 2

The reaction steps and operations are the same as those of Comparative Example 1, except that the reaction solvent is n-hexane (80 mL), and the second step reaction is continued at 69 degrees Celsius for 4 hours. The reaction was stopped, and the target product 1a (0.43 g, yield 10%) was obtained after post-processing.

Comparative example 3

The reaction steps and operations are the same as those of Comparative Example 1, except that the reaction solvent is n-hexane (80 mL), and the second step reaction is continued at 69 degrees Celsius for 10 hours. The reaction was stopped, and the target product 1a (0.52 g, yield 12%) was obtained after post-processing.

Comparative example 4

The reaction steps and operations are the same as those of Comparative Example 1, except that the second step reaction was continued at 110 degrees Celsius for 10 hours. The reaction was stopped, and the target product 1a (1.38 g, yield 32%) was obtained after post-processing.

Comparative Example 5 to Comparative Example 6

Reaction steps and operation are the same as comparative example 4, and difference with comparative example 4 is to use the fourth subgroup metal chloride difference:

Comparative example Subgroup IV Metal Chlorides (MCl ₄ ) product Yield (%) 5 Titanium tetrachloride (1.90g, 10mmol) 1b 13 6 Hafnium tetrachloride (3.20g, 10mmol) 1c 28

Comparative Example 7 to Comparative Example 20

Reaction steps and operation are the same as Comparative Example 4, and the difference from Comparative Example 4 is that the use of cyclopentadiene derivatives (Cp'H) is different:

Comparative example Cyclopentadiene Derivatives (Cp'H) product Yield (%) 7 5-Trimethylsilylcyclopentadiene (2.76g, 20mmol) 1d 27 8 5-Benzylcyclopentadiene (3.12g, 20mmol) 1f twenty two 9 1,3-Dimethyl-1,3-cyclopentadiene (1.88g, 20mmol) 1h 33 10 Fluorene (3.32g, 20mmol) 1i 17 11 2-Phenylindene (3.84g, 20mmol) 1j 32 12 1-Methylindene (2.60g, 20mmol) 1k 35 13 1-Trimethylsilylindene (3.77g, 20mmol) 1l 33 14 1,2,4-Trimethyl-1,3-cyclopentadiene (2.16g, 20mmol) 1n 28 15 1,2,3,4-Tetramethyl-1,3-cyclopentadiene (2.44g, 20mmol) 1o 33 16 1-n-Butylindene (3.44g, 20mmol) 1q 27 17 1-benzylindene (4.12g, 20mmol) 1r 28 18 2-n-Butylindene (3.44g, 20mmol) 1s 25 19 1,2-Dimethylindene (2.88g, 20mmol) 1w twenty one 20 1,2,5-Trimethylindene (3.16g, 20mmol) 1x 20

Application example 1

Using the non-bridged symmetrical metallocene complex as a catalyst can effectively promote the oligomerization of 1-decene to obtain a low-viscosity polyα-olefin product. Specific application examples are as follows:

Preparation of metallocene catalyst: Weigh bis(1-methylindenyl)zirconium dichloride (1k) (13.5mg, 0.032mmol) and dissolve it in 10ml of toluene solution (the amount of metallocene is 0.0086mol%), add 6.0ml concentration of 1.5 M methylaluminoxane toluene solution (cocatalyst) (cocatalyst/(metallocene (1k)=281 (molar ratio)), stirred for 30 minutes and set aside.

Polymerization reaction: Vacuumize/inflate a 250ml Schlenk reaction bottle with nitrogen for 3 times, and add 1-decene (70mL, 51.9g, 370mmol) that has been treated with anhydrous and anaerobic conditions under nitrogen. The temperature of the reaction system was raised to 90 degrees Celsius, and after 15 minutes, the pre-prepared metallocene catalyst was added, and the reaction was started under stirring. After the reaction was carried out under nitrogen atmospheric pressure for 2 hours, the samples were analyzed by gas chromatography internal standard method, the conversion rate of raw materials was 99.1%, and the dimer selectivity was 23.4%. Stop the reaction, add 5% hydrochloric acid ethanol solution (10mL) in the system, continue to stir for 30 minutes to quench the reaction, filter through diatomaceous earth to obtain the crude product solution, remove the solvent, unreacted 1-decene and low-pressure distillation Boiling point components, the oligomerized product (36.4 g) was obtained with a yield of 70.1%. The hydrogenation of the oligomerization product is carried out in a 500 ml high-pressure reactor, the hydrogenation catalyst is a nickel catalyst, the reaction temperature is 130 degrees Celsius, the reaction pressure is 4 MPa, and the reaction time is 4 hours. The metallocene PAO product is obtained after post-treatment, and its kinematic viscosity is measured according to the corresponding standard. (100 degrees Celsius) is 4.4mm ² /s, viscosity index is 134, and pour point is -57 degrees Celsius.

The test methods for the viscosity and temperature properties of PAO in the application examples are as follows:

a. Petroleum product kinematic viscosity determination method and kinematic viscosity calculation method: GB/T 265-88

b. Calculation method of viscosity index of petroleum products: GB/T 1995-1998

c. Determination of pour point of petroleum products: GB/T 3535-2006

Application example 2

Reaction steps and operation are the same as Application Example 1, and the difference with Application Example 1 is that the metallocene catalyst is two (pentamethylcyclopentadienyl) zirconium dichloride (1a) in the reaction, after the reaction finishes, through gas chromatography As detected by the internal standard method, the conversion rate of raw materials is 98.9%, the selectivity of dimer is 29.6%, and the yield of oligomerization product is 66.2%. After measurement, the metallocene PAO has a kinematic viscosity (100 degrees Celsius) of 4.1 mm ² /s, a viscosity index of 135, and a pour point of -54 degrees Celsius.

The above-mentioned embodiments are only preferred embodiments for fully illustrating the present invention, and the protection scope of the present invention is not limited thereto. Equivalent substitutions or transformations made by those skilled in the art on the basis of the present invention are all within the protection scope of the present invention. The protection scope of the present invention shall be determined by the claims.

Claims (13)

1. A method for preparing a non-bridged symmetric metallocene catalyst, characterized in that, using the fourth subgroup metal chloride, C1-C3 alkyl metal reagents and cyclopentadiene derivatives as raw materials, in nitrogen or argon Under ambient conditions and in an organic solvent, a non-bridged symmetric metallocene catalyst is obtained through a one-pot two-step reaction. 2. the method for preparing non-bridged symmetrical metallocene catalyst described in claim 1, is characterized in that, comprises: (1) At a certain feed temperature, 2 equivalents of C1-C3 alkyl metal reagents are added to the mixture of the fourth subgroup metal chloride and the organic solvent, and react at room temperature to obtain the mixture; (2) At a certain feed temperature, add 2 equivalents of cyclopentadiene derivatives to the mixture obtained in step (1), and react at a certain reaction temperature. 3. The method for preparing a non-bridged symmetrical metallocene catalyst according to claim 2, wherein the general formula of the fourth subgroup metal chloride is MCl ₄ , wherein M is the element titanium, zirconium, and hafnium. 4. The method for preparing non-bridged symmetrical metallocene catalysts according to claim 2, characterized in that, the C1-C3 alkyl metal reagent is RLi, R ₂ Zn or RMgX; wherein, R is the normal structure of C1-C3 Alkyl, X is halogen chlorine, bromine or iodine. 5. the method for preparing non-bridged symmetrical metallocene catalyst described in claim 2, is characterized in that, described cyclopentadiene derivative can be selected from following compound:

Wherein, R ¹ is C2-C4 carbon chain alkyl, benzyl, trimethylsilyl; n is an integer of 2-5; when R ³ is hydrogen, R ² can be C1-C4 carbon chain alkyl , benzyl, trimethylsilyl; when R ² is hydrogen, R ³ can be C1-C4 carbon chain alkyl, benzyl, phenyl, 4-methylphenyl, 4-methoxyphenyl ; R ² and R ³ can be methyl, ethyl at the same time; R ⁴ can be hydrogen, methyl, phenyl. 6. The method for preparing a non-bridging symmetrical metallocene catalyst according to claim 2, characterized in that, the certain feed temperature is -78-0 degrees Celsius; the certain reaction temperature is 25-140 degrees Celsius. 7. The method for preparing a non-bridged symmetric metallocene catalyst according to claim 6, characterized in that, the certain feed temperature is -40--10 degrees Celsius; the certain reaction temperature is 60-110 degrees Celsius. 8. the method for preparing non-bridged symmetrical metallocene catalyst described in claim 2, is characterized in that, described organic solvent is normal hexane, normal heptane, toluene, o-xylene, tetrahydrofuran, 2-methyltetrahydrofuran, ether or Ethylene glycol dimethyl ether. 9. The method for preparing a non-bridged symmetrical metallocene catalyst according to claim 2, characterized in that, the reaction time of step (1) is 4-8 hours; the reaction time of step (2) is 5-10 hours. 10. The non-bridged symmetric metallocene catalyst prepared by the method according to any one of claims 1-9. 11. The application of the non-bridged symmetrical metallocene catalyst in claim 10 in olefin polymerization. 12. Olefin polymerization, characterized in that the non-bridged symmetric metallocene catalyst according to claim 10 is used. 13. The olefin polymerization reaction according to claim 12, characterized in that, the olefin polymerization reaction is 1-decene polymerization reaction.