CN102977229B - Method for synthetizing C2 bridging fiber metallocene dikaryon catalyst - Google Patents

Abstract

The present invention provides the hetero-C2 bridged metallocene dinuclear catalyst represented by the following structural formula, wherein M is Ti or Zr. The invention also provides a preparation method of the catalyst. The catalyst is used for olefin polymerization in combination with cocatalyst alkyl aluminoxane, has high polymerization activity, and can obtain olefin polymerization products with high molecular weight and wide molecular weight distribution.

Description

A kind of synthetic method of C2 bridged metallocene binuclear catalyst

technical field

The invention belongs to the field of polyolefin and relates to a catalyst for olefin polymerization, in particular to a bimetallic catalyst for ethylene and propylene polymerization and a preparation method thereof. the

Background technique

Metallocene catalysts have a single active center, high catalyst activity, and polymers with very high tacticity can be obtained, and the obtained polymers have high molecular weight, and the molecular weight and molecular weight distribution can be controlled by changing the ligand structure. extensive attention. However, due to the narrow molecular weight distribution of polyolefin obtained, it is difficult to process, which limits its industrialization process. People try to use composite catalysis (see KAMINSKY W, STEIGER R. Polymerization of olefins with homogeneous zirconocene/alumoxane catalysts, Polyhedron, 1988, 7 (22-23): 2375-2381) or dual-core multi-nuclear catalysts (see Feng Zuofeng, Xie Jun, Chen Bin et al., Organic Chemistry, 2001, 21 (1), 33-40) to improve the molecular weight distribution of polymers.

Green and his colleagues synthesized Si-bridged binuclear compounds (T.Ushioda, MLHGreen, J.Haggitt, X.Yan, J.Organomet.Chem., 1996,518,155). The bridging di(cyclopentadiene) dianion first reacts with one equivalent of CpMCl ₃ to obtain a compound in which the central ion coordinates with three cyclopentadienes, and then reacts with a second equivalent of a metal halide (Cp'MCl ₃ Or MCl ₄ ) reaction to obtain dinuclear compounds. The dinuclear compound is used for ethylene polymerization with high activity (higher than 8.5×10 ⁶ gPE/mol M h, the mononuclear compound M[(η-C ₅ H ₅ ) ₂ Cl ₂ ] is 3.6×10 ⁶ gPE/mol M h); the molecular weight distribution becomes broadened (M _w /M _n >5.4). Used for propylene polymerization to obtain random polypropylene (mm<0.39, generally homogeneous Ziegler-Natta catalyst mm>0.90). The authors suggest that there may be more than one active center.

CN1428355 discloses a dinuclear metallocene compound and its preparation and application in olefin polymerization. It discloses a dimethyl silicon bridged dinuclear compound, which is used for ethylene polymerization, and the highest activity can reach 10 ⁶ gPE/mol Cat .

Although the above-mentioned literatures reported the dual-core catalyst, although its catalytic performance is higher than that of the single-core catalyst, it did not obtain a bimodal polymer. Chinese patent applications 200710015194.2 and 200710015193.8 disclose bridged metallocene binuclear catalysts and their preparation methods, but there are defects of many steps, high cost and low overall yield. 201110030833.9 discloses a C2 bridged metallocene Zr-rare earth binuclear catalyst and its preparation method, but the reaction is complex, requiring a large excess of one reactant, and the post-treatment is cumbersome. the

Contents of the invention

The purpose of the present invention is to provide a preparation method of the C2 bridged metallocene binuclear catalyst, the preparation method has few steps, easy to obtain raw materials, low cost and easy industrialization. the

The C2 bridged metallocene dinuclear catalyst and the alkylaluminoxane of the invention are used as cocatalysts to catalyze the polymerization of ethylene or propylene to obtain polyolefins with a wide molecular weight distribution. The polymerization method can adopt bulk polymerization or solution polymerization. the

A C2 bridged metallocene binuclear catalyst, its structure is as follows:

wherein M is Ti or Zr.

The present invention also provides the synthetic method of described C2 bridged metallocene binuclear catalyst, comprises the following steps:

1) Synthesis of fluorenyl ligands

Dissolve 9-chloro-10-bromo-1-decene in an organic solvent, cool down to -20-10°C, slowly add fluorene lithium solution dropwise for 1-2 hours, and continue the reaction for 12-16 hours after the addition is complete ;

The molar ratio of 9-chloro-10-bromo-1-decene to fluorene lithium is: 9-chloro-10-bromo-1-decene: fluorene lithium = 1~1.1:1; the organic solvent is selected from anhydrous ether or petroleum ether.

2) Synthesis of C2 bridged indenyl fluorenyl ligands

Step 1) adding solvent tetrahydrofuran to the obtained fluorenyl ligand, and then reacting with indenyl lithium to obtain a C2 bridged indenyl fluorenyl ligand. The molar ratio of fluorenyl ligand to indene lithium is 1:1~1.1; the reaction temperature is -30°C~0°C; the reaction time is 13~16 hours.

3) Synthesis of Ligand Lithium Salt

Dissolve the ligand obtained in step 2) in n-hexane, add n-butyllithium dropwise, the dropping temperature is -20-10°C, the molar ratio of ligand to n-butyllithium is 1:2.0-2.4, add dropwise After completion, naturally rise to room temperature and react for 12 to 16 hours. The n-hexane was removed by filtration, and the n-hexane was sucked dry under reduced pressure to obtain the ligand lithium salt.

4) Synthesis of C2 bridged metallocene binuclear catalysts

Step 3) adding toluene to the obtained ligand lithium salt to obtain a white turbid liquid, that is, the suspension of the above lithium salt, adding CpZrCl ₃ DME or CpTiCl ₃ at -10-20°C, wherein DME is ethylene glycol dimethyl ether, Cp is cyclopentadienyl. The molar ratio of CpZrCl ₃ DME or CpTiCl ₃ to ligand lithium salt is 2 to 2.3:1, the reaction temperature is -10 to 20°C, and the reaction is stirred for 10 to 20 hours. Extracting, combining all the extracts with the liquid obtained by centrifugation, concentrating until a solid appears, and standing at -25°C to -15°C for 20 to 30 hours to obtain the compound C2 bridged metallocene binuclear catalyst.

Preferably, the organic solvent in step 1) is selected from anhydrous diethyl ether or petroleum ether. The reaction temperature is -20~-10°C, and the reaction time is 12~14 hours; the molar ratio of 9-chloro-10-bromo-1-decene to fluorene lithium is: 9-chloro-10-bromo-1-decene : Lithium fluorene = 1:1. the

Preferably, in step 2), the reaction temperature is -20°C to -10°C; the reaction time is 14 to 16 hours; the molar ratio of indene to lithium is 1:1; the solvent is tetrahydrofuran. the

Preferably, in step 3), the dropping temperature is -10-0°C. The molar ratio of the ligand to n-butyllithium is 1:2.0~2.2. After the dropwise addition is completed, naturally rise to room temperature and react for 12~14 hours. the

Preferably, in step 4), the reaction temperature is 0-10°C. Stir the reaction for 10-15 hours. the

Under the same catalytic conditions, the catalytic activity of the C2 bridged metallocene binuclear catalyst obtained by the present invention is higher than that of the mononuclear metallocene catalyst such as cyclopentadienyl titanium dichloride Cp ₂ TiCl ₂ or cyclopentadienyl dichloride The catalytic activity of zirconium Cp ₂ ZrCl ₂ is high, and the molecular weight of the polymer is obviously increased, and the molecular weight distribution is broadened.

Compared with the methods reported in literature, the synthesis method of the present invention has short synthesis route, high yield, avoids the use of expensive reagents, and has better industrialization prospects. the

Detailed ways

The preparation method of C2 bridged metallocene binuclear catalyst is as follows:

1) Synthesis of fluorenyl ligands

Dissolve 9-chloro-10-bromo-1-decene in an organic solvent, cool down to -20-10°C, slowly add fluorene lithium solution dropwise for 1-2 hours, and continue the reaction for 12-16 hours after the addition is complete .

The molar ratio of 9-chloro-10-bromo-1-decene to fluorene lithium is: 9-chloro-10-bromo-1-decene: fluorene lithium = 1~1.1:1; the organic solvent is selected from anhydrous ether or petroleum ether. the

The synthesis method is shown in the following formula:

.

The choice of solvent is very important. Using anhydrous ether or petroleum ether as a solvent can effectively control the degree of reaction, and can control the reaction of Br in 9-chloro-10-bromo-1-decene, while Cl does not react. . When using dichloromethane, toluene or tetrahydrofuran and other polar solvents, both Br and Cl will participate in the reaction, and the selectivity of the reaction will decrease. the

When using 9,10-dichloro-1-decene as the reactant, the lithium fluorene solution should be slowly added dropwise to the 9-chloro-10-bromo-1-decene solution, and the 9- Chloro-10-bromo-1-decene in excess. Improper control of conditions can produce 9,10-diindenyl-1-decene. 9,10-diindenyl-1-decene cannot undergo the next step reaction and needs to be separated by gel column. However, the present invention utilizes the difference in reactivity between Br and Cl to obtain the target product through the selection of suitable reaction conditions. Separation of later products is avoided. The reaction temperature is -30-0°C, and the reaction temperature does not need to be too low. the

The concentration of 9-chloro-10-bromo-1-decene is not limited, and those skilled in the art can select an appropriate concentration according to actual conditions. Lithium fluorene is synthesized from fluorene and butyllithium by a known method. Butyllithium can be purchased or prepared according to known methods from Li band and chlorobutane in petroleum ether or n-hexane solvent. the

After the reaction was completed, most of the solvent was distilled off under reduced pressure, and separated by a chromatographic column to obtain 10-indenyl-9-chloro-1-decene, which was stored for future use. It can also be separated without chromatographic column. After the reaction is completed, the solvent is evaporated and the next reaction is directly carried out. the

2) Synthesis of C2 bridged indenyl fluorenyl ligands

Step 1) adding solvent tetrahydrofuran to the obtained fluorenyl ligand, and then reacting with indenyl lithium to obtain a C2 bridged indenyl fluorenyl ligand. The molar ratio of fluorenyl ligand to indene lithium is 1:1~1.1; the reaction temperature is -30°C~0°C; the reaction time is 13~16 hours.

If the fluorenyl ligand obtained in step 1) is directly subjected to the reaction in step 2) without distilling off the organic solvent, the reaction speed is very slow and the product yield is low. We found that when tetrahydrofuran was used as the solvent in step 2), there were few side reactions, the reaction could occur rapidly, and the yield of the obtained ligand was high. the

Indene lithium is synthesized from indene and butyllithium by a known method. Butyllithium can be purchased or prepared from chlorobutane and Li according to known methods. The order of adding the fluorenyl ligand and indene lithium is not particularly limited, and the method of adding the indene lithium solution to the fluorenyl ligand dropwise is preferred. the

The synthesis method is shown in the following formula:

.

3) Synthesis of Ligand Lithium Salt

Dissolve the ligand obtained in step 2) in n-hexane, add n-butyllithium dropwise, the dropping temperature is -20-10°C, the molar ratio of ligand to n-butyllithium is 1:2.0-2.4, add dropwise After completion, naturally rise to room temperature and react for 12 to 16 hours. The n-hexane was removed by filtration, and the n-hexane was sucked dry under reduced pressure to obtain the ligand lithium salt.

The lithium salt of the ligand obtained after draining the n-hexane is easy to store and can be easily prepared into various solutions or suspensions. It is also possible not to drain the solvent, and directly proceed to the next step of synthesis after concentration. the

4) Synthesis of C2 bridged metallocene binuclear catalysts

Step 3) adding toluene to the obtained ligand lithium salt to obtain a white turbid liquid, that is, the suspension of the above lithium salt, adding CpZrCl ₃ DME or CpTiCl ₃ at -10-20°C, wherein DME is ethylene glycol dimethyl ether, Cp is cyclopentadienyl. The molar ratio of CpZrCl ₃ DME or CpTiCl ₃ to ligand lithium salt is 2 to 2.3:1, the reaction temperature is -10 to 20°C, and the reaction is stirred for 10 to 20 hours. Extracting, combining all the extracts with the liquid obtained by centrifugation, concentrating until a solid appears, and standing at -25°C to -15°C for 20 to 30 hours to obtain the compound C2 bridged metallocene binuclear catalyst.

In the catalyst preparation of the present invention, the choice of solvent is very important; different solvents are used in different reaction steps, which is beneficial to the progress of the reaction and also to the improvement of the yield. We found that the selection of solvents in the preparation process does not fully follow the principle of "like dissolves like". For example, in the reaction involving lithium salts, the yield of non-polar solvents such as petroleum ether is higher than that of tetrahydrofuran. After a large number of experiments, we found that using the solvent of the present invention has the highest reaction yield. The choice of solvent also determines whether Br in 9-chloro-10-bromo-1-decene reacts, or both Br and Cl react; When , it is possible to control the reaction of Br atoms but not the reaction of Cl; but at the same time, it is also surprising to find that the reaction yield is not high when using non-polar pentane solvent. the

Each of the above reactions needs to be carried out under an inert atmosphere, using shenlink technology, and the inert gas is argon or nitrogen.

The compound provided by the invention can be used as the main catalyst for C2-C10 alpha-olefin homopolymerization or copolymerization. It is also necessary to add alkyl aluminoxane as co-catalyst during polymerization. The preferred co-catalyst is methyl aluminoxane. During the polymerization reaction, the molar ratio of Al in the co-catalyst to metal in the main catalyst is 250-1500:1, preferably 250-1000:1. The polymerization conditions are 30-80°C, 0.1-0.8MPa. Olefins used for homopolymerization or copolymerization are preferably ethylene, propylene, butene, hexene or octene. The polymerization method can adopt bulk polymerization or solution polymerization. The analysis method and polymer description adopt the method described in 201110030833.9. the

The following examples are further illustrations of the present invention, but the present invention is not limited thereto. the

Embodiment 1 :

1) Synthesis of fluorenyl ligands

Dissolve 9-chloro-10-bromo-1-decene in petroleum ether, lower the temperature to -20°C, slowly add fluorene lithium solution dropwise for 2 hours, and continue the reaction for 12 hours after the addition; 9-chloro-10 The molar ratio of bromo-1-decene to fluorene lithium is: 9-chloro-10-bromo-1-decene: fluorene lithium = 1:1. the

2) Synthesis of C2 bridged indenyl fluorenyl ligands

Step 1) adding solvent tetrahydrofuran to the obtained fluorenyl ligand, and then reacting with indenyl lithium to obtain a C2 bridged indenyl fluorenyl ligand. The molar ratio of fluorenyl ligand to indene lithium is 1:1; the reaction temperature is -20°C; the reaction time is 16 hours.

3) Synthesis of Ligand Lithium Salt

Dissolve the ligand obtained in step 2) in n-hexane, add n-butyllithium dropwise, the dropping temperature is -20°C, the molar ratio of ligand to n-butyllithium is 1:2.2, after the addition is completed, the natural rise to room temperature and reacted for 14 hours. The n-hexane was removed by filtration, and the n-hexane was sucked dry under reduced pressure to obtain the ligand lithium salt.

4) Add toluene to the ligand lithium salt obtained in step 3) to obtain a white turbid liquid, that is, the suspension of the above lithium salt, add CpZrCl ₃ DME at -10°C, where DME is ethylene glycol dimethyl ether, and Cp is cyclic pentadienyl. The molar ratio of CpZrCl ₃ DME to ligand lithium salt is 2:1, the reaction temperature is -10°C, and the reaction is stirred for 15 hours. The reaction product is separated by centrifugation, and the residual solid is extracted with dichloromethane. The liquids were combined, concentrated until a solid appeared, and placed at -20°C for 20 hours to obtain the compound C2 bridged metallocene binuclear catalyst.

Example 2

Others are the same as embodiment 1, the difference is:

1) Synthesis of fluorenyl ligands

Dissolve 9-chloro-10-bromo-1-decene in petroleum ether, lower the temperature to -10°C, slowly add the fluorene lithium solution dropwise for 1.5 hours, and continue the reaction for 16 hours after the addition; 9-chloro-10 The molar ratio of bromo-1-decene to lithium fluorene is: 9-chloro-10-bromo-1-decene:lithium fluorene=1.1:1. the

2) Synthesis of C2 bridged indenyl fluorenyl ligands

Step 1) adding solvent tetrahydrofuran to the obtained fluorenyl ligand, and then reacting with indenyl lithium to obtain a C2 bridged indenyl fluorenyl ligand. The molar ratio of fluorenyl ligand to indene lithium is 1:1; the reaction temperature is -10°C; the reaction time is 14 hours.

3) Synthesis of Ligand Lithium Salt

Dissolve the ligand obtained in step 2) in n-hexane, add n-butyllithium dropwise, the dropping temperature is 0°C, and the molar ratio of ligand to n-butyllithium is 1:2.4. At room temperature, react for 12 hours. The n-hexane was removed by filtration, and the n-hexane was sucked dry under reduced pressure to obtain the ligand lithium salt.

4) Add toluene to the ligand lithium salt obtained in step 3) to obtain a white turbid liquid, that is, the suspension of the above lithium salt, add CpZrCl ₃ DME at 0°C, where DME is ethylene glycol dimethyl ether, and Cp is cyclopentyl dienyl. The molar ratio of CpZrCl ₃ DME to ligand lithium salt was 2.1:1, the reaction temperature was 0°C, and the reaction was stirred for 10 hours. The reaction product was separated by centrifugation, and the residual solid was extracted with dichloromethane. The liquids were combined, concentrated until a solid appeared, and placed at -15°C for 30 hours to obtain the compound C2 bridged metallocene binuclear catalyst.

Example 3

Others are the same as embodiment 1, the difference is:

1) Synthesis of fluorenyl ligands

Dissolve 9-chloro-10-bromo-1-decene in anhydrous ether, lower the temperature to 0°C, slowly add fluorene lithium solution dropwise for 1 hour, and continue the reaction for 14 hours after the addition; 9-chloro-10 The molar ratio of bromo-1-decene to fluorene lithium is: 9-chloro-10-bromo-1-decene: fluorene lithium = 1:1.

2) Synthesis of C2 bridged indenyl fluorenyl ligands

Step 1) adding solvent tetrahydrofuran to the obtained fluorenyl ligand, and then reacting with indenyl lithium to obtain a C2 bridged indenyl fluorenyl ligand. The molar ratio of fluorenyl ligand to indene lithium is 1:1; the reaction temperature is -5°C; the reaction time is 13 hours.

3) Dissolve 0.0266 mol of ligand in 80 ml of n-hexane, add 0.0585 mol of n-butyllithium dropwise in an ice-water bath, remove the ice-water bath after the dropwise addition, let it rise naturally to room temperature, and react for 12 hours. The solvent was removed by filtration and vacuum-dried to obtain a white powdery solid. For the ligand lithium salt. the

Toluene was added to the obtained ligand lithium salt to obtain a white turbid liquid, that is, the suspension of the above lithium salt, and CpZrCl ₃ DME was added at 20°C, wherein DME was ethylene glycol dimethyl ether, and Cp was cyclopentadienyl. The molar ratio of CpZrCl ₃ DME to ligand lithium salt was 2.3:1, the reaction temperature was 20°C, and the reaction was stirred for 18 hours. The reaction product was separated by centrifugation, and the residual solid was extracted with dichloromethane. The liquids were combined and concentrated until a solid appeared, and left at -25 for 20 hours to obtain the compound C2 bridged metallocene binuclear catalyst in the form of brown crystals.

The NMR data are as follows:

¹ H NMR (CDCl3, 25°C): 7.98(d, J=8.4Hz,1H), 7.82(d,J=8.4Hz,1H), 7.74(d,J=8.5Hz,1H), 7.65(2H) , 7.51(6H), 7.10(2H), 6.51(t,2H,C ₅ H ₅ , a, J _HH =2.63Hz), 6.44(d,8H,C ₅ H ₅ ,a, J _HH =5.04Hz) , 5.92(s,1H,CH _ind ), 5.72(m,1H,=CH), 4.93(m,1H,=CH ₂ ), 4.35(m,1H,CH ₂ ), 4.15(2H, CH ₂ ), 3.85(m,1H, CH ₂ ), 2.63(m,1H, CH ₂ ), 2.52(m,1H, CH ₂ ), 1.96(m,2H, CH ₂ ), 1.40-1.29(4H, CH ₂ ),

¹³ C NMR (CDCl3, 25°C): 138.2(=CH), 128.7, 128.2(CH), 127.2, 127.1(Cq), 126.1, 125.7(CH), 125.5, 125.4(Cq), 125.3, 125.1, 124.9, 124.7, 123.9(CH), 123.4, 123.3, 122.6(Cq), 122.5, 122.4(CH), 121.4(Cq), 120.9(CH), 115.8, 115.6, 115.5, 115.4, 115.2, 615.0, 114. , 114.5, 114.3(=CH ₂ ), 113.5(CH _ind ), 103.6(Cq _ind ), 33.5, 30.1, 29.8, 29.3, 28.8, 28.2(CH ₂ ).

The obtained compound is combined with cocatalyst alkyl aluminoxane to catalyze ethylene polymerization, the activity is as high as 3.15×10 ⁵ g ethylene/mmol Zr h, Mw/Mn=3.23, and the molecular weight distribution is wider than that of polyethylene synthesized by Cp ₂ ZrCl ₂ catalysis.

Example 4:

Others are the same as in Example 3, except that CpZrCl ₃ DME is replaced by CpTiCl ₃ , the molar ratio of CpTiCl ₃ to ligand lithium salt is 2.1:1, the reaction temperature is 30°C, and the reaction is stirred for 12 hours. The reaction product is centrifuged and the residual The solid was then extracted with dichloromethane, all the extracts were combined with the liquid obtained by centrifugation, concentrated until a solid appeared, and placed at -25°C to -15°C for 30 hours to obtain the compound C2 bridged metallocene binuclear catalyst as red crystals.

The obtained compound is combined with cocatalyst alkyl aluminoxane to catalyze ethylene polymerization, the activity is as high as 1.2×10 ⁵ g ethylene/mmol Zr h, Mw/Mn=3.42, and the molecular weight distribution is wider than that of polyethylene synthesized by Cp ₂ ZrCl ₂ catalysis.

Claims (4)

1. a synthetic method of C2 bridged metallocene binuclear catalyst, comprises the following steps: 1) Synthesis of fluorenyl ligands Dissolve 9-chloro-10-bromo-1-decene in an organic solvent, cool down to -20-10°C, slowly add fluorene lithium solution dropwise, dropwise for 1-2 hours, continue to react for 12-16 hours after dropping ; The molar ratio of 9-chloro-10-bromo-1-decene to fluorene lithium is: 9-chloro-10-bromo-1-decene: fluorene lithium = 1 ~ 1.1: 1; the organic solvent is selected from anhydrous ether or petroleum ether; 2) Synthesis of C2 bridged indenyl fluorenyl ligand Step 1) adding solvent tetrahydrofuran to the obtained fluorenyl ligand, and then reacting with indene lithium to obtain a C2 bridged indenyl fluorenyl ligand; the molar ratio of fluorenyl ligand to indene lithium is 1:1; the reaction temperature -20℃～-10℃; reaction time is 14～16 hours; 3) Synthesis of Ligand Lithium Salt Dissolve the ligand obtained in step 2) in n-hexane, add n-butyllithium dropwise, the dropping temperature is -20-10°C, the molar ratio of ligand to n-butyllithium is 1:2.0-2.4, add dropwise After completion, naturally rise to room temperature, and react for 12 to 16 hours; remove n-hexane by filtration, and drain n-hexane under reduced pressure to obtain ligand lithium salt; 4) Synthesis of C2 bridged metallocene binuclear catalysts Step 3) Add toluene to the obtained ligand lithium salt to obtain a white turbid liquid, that is, the suspension of the above lithium salt, add CpZrCl ₃ ·DME or CpTiCl ₃ at -10-20°C, wherein DME is ethylene glycol dimethyl ether , Cp is cyclopentadienyl; the molar ratio of CpZrCl ₃ ·DME or CpTiCl ₃ to the ligand lithium salt is 2~2.3:1, the reaction temperature is -10~20°C, the reaction is stirred for 10~20 hours, and the reaction product is passed through Centrifuge, and extract the residual solid with dichloromethane, combine all the extracts with the liquid obtained by centrifugation, concentrate until solid appears, and place it at -25°C to -15°C for 20 to 30 hours to obtain the compound C2 bridged metallocene binuclear catalyst : M is Ti or Zr. 2. The synthetic method of C2 bridged metallocene binuclear catalyst as claimed in claim 1, is characterized in that, in step 1), organic solvent is selected from anhydrous ether or sherwood oil; Reaction temperature is-20～-10 ℃, The reaction time is 12 to 14 hours; the molar ratio of 9-chloro-10-bromo-1-decene to fluorene lithium is: 9-chloro-10-bromo-1-decene: fluorene lithium = 1:1. 3. The synthetic method of C2 bridged metallocene binuclear catalyst as claimed in claim 1, is characterized in that, in step 3), the dropping temperature is-10～0 ℃; The molar ratio of part and n-butyllithium is 1: 2.0～2.2, after the dropwise addition, naturally rise to room temperature, and react for 12～14 hours. 4. The synthesis method of C2 bridged metallocene binuclear catalyst as claimed in claim 1, characterized in that, in step 4), the reaction temperature is 0-10°C; the reaction is stirred for 10-15 hours.