A process for the preparation of polybutadiene

Abstract

The present application relates to a kind of preparation methods of polybutadiene.The method steps are as follows: step one: 1,3-butadiene monomer and catalyst are added to alkyl solvent according to the proportion of (2000~10000) :1 mole ratio to carry out polymerization reaction, and the reaction solution is obtained;Step two: polybutadiene is condensed from the above reaction solution with ethanol.The novel molecular weight regulator used in the present application can accurately and efficiently control the molecular weight of polybutadiene, control the molecular structure of polybutadiene, and the prepared polybutadiene has low molecular weight and high 1,4-structure content.

Description

Technical fields:

[0001] This invention relates to a method for preparing polybutadiene. Background technology:

[0002] Liquid rubber is generally a polymer with an index-average molecular weight of 500-10000, and its viscosity varies with the relative molecular mass and molecular configuration. Compared with solid rubber, liquid rubber has a lower relative molecular mass, is a free-flowing liquid at room temperature, and is easy to process and mold. The development of various liquid rubbers has largely kept pace with that of their corresponding solid rubbers.

[0003] Low molecular weight polybutadiene (LMW) is a type of liquid rubber. LMW and its modified products exhibit excellent adhesion and uniformity, and can be used as reactive plasticizers and softeners to improve the processability of rubber and enhance the physical and processing properties of low-hardness rubber products. Due to these superior properties, LMW is widely used in tires, wires and cables, sealing strips, hoses, seals, printing and textile rollers, footwear, adhesives, and other fields.

[0004] The number average molecular weight of low molecular weight polybutadiene is generally 1,000-10,000. If you want to obtain low molecular weight polybutadiene with a high 1,4-structure, you generally need to use an anionic polymerization catalytic system.

[0005] Chinese patent document CN10168003A discloses a method for preparing low molecular weight polybutadiene using a rare earth sulfonic acid catalyst. However, the polybutadiene prepared by this method has a wide molecular weight distribution. Another method uses lithium-based catalysts to prepare polybutadiene with narrow molecular weight distributions of various molecular weights; however, the polybutadiene synthesized by lithium-based catalysts mainly has a 1,2-structure, with a low content of 1,4-structures. Traditional Ziegler-Natta catalysts are not suitable for preparing low molecular weight polybutadiene. Summary of the Invention:

[0006] The technical problem to be solved by this invention is to provide a method for preparing polybutadiene, which achieves high catalyst utilization efficiency and produces polybutadiene with low molecular weight and high 1,4-structure content. This overcomes the shortcomings of existing polybutadiene preparation methods that struggle to produce polybutadiene with low molecular weight and high 1,4-structure content.

[0007] The technical solution adopted in this invention is: a method for preparing polybutadiene, the steps of which are as follows:

[0008] Step 1: Add 1,3-butadiene monomer and catalyst to an alkane solvent at a molar ratio of (2000-10000):1 to carry out polymerization reaction and obtain reaction solution;

[0009] Step 2: Polybutadiene is condensed from the above reaction solution using ethanol;

[0010] The catalyst was prepared by the following method: rare earth compound, 1,3-butadiene monomer, alkyl aluminum hydride and molecular weight regulator were mixed and reacted to obtain a mixed solution, and chloride was added to the mixed solution to react and obtain the catalyst.

[0011] The molar ratio of the rare earth compound, alkyl aluminum hydride, chloride, 1,3-butadiene monomer, and molecular weight regulator is 1:10-100:1-5:5-100:1-10.

[0012] Preferably, the catalyst is prepared by mixing a rare earth compound, alkyl aluminum hydride, 1,3-butadiene monomer, and a molecular weight regulator, and reacting the mixture at -20°C to 50°C for 10 min to 24 h to obtain a mixed solution. Then, chloride is added to the mixed solution and reacted at 0 to 60°C for 5 min to 60 min to obtain the catalyst.

[0013] Preferably, step one further includes adding an ethanol solution of 2,6-di-tert-butyl-p-methylphenol to the reaction solution.

[0014] Preferably, the mass concentration of the 2,6-di-tert-butyl-p-methylphenol is 1% to 2% g / ml.

[0015] Preferably, the molecular weight regulator is a C4-C10 alcohol or a C4-C10 metal alcohol compound.

[0016] Preferably, the rare earth compound is one or more rare earth carboxylates and rare earth phosphates.

[0017] Preferably, the rare earth carboxylate is one or more of neodymium neodecanoate, neodymium naphthenate, and neodymium isooctanoate, and the rare earth phosphate is one or more of neodymium phosphate (P507) and neodymium phosphate (P204).

[0018] Preferably, the chloride is sesquiethylaluminum chloride, diisobutylaluminum chloride, diethylaluminum chloride, dichlorodimethylsilane, trimethylchlorosilane, trichloromethylsilane, silicon tetrachloride, dichlorodiphenylsilane, or trichlorosilane.

[0019] Preferably, the alkyl aluminum hydride is diisobutylaluminum hydride, diethylaluminum hydride, or dialkylaluminum hydride.

[0020] Preferably, the alkane solvent is hexane, cyclohexane, or heptane.

[0021] The beneficial effects of this invention are: the catalyst used in this invention has high utilization efficiency, and the prepared polybutadiene has low molecular weight and high 1,4-structure content. Detailed implementation method:

[0022] To further understand the present invention, preferred embodiments of the present invention are described below in conjunction with examples. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, and not for limiting the claims of the present invention.

[0023] This invention provides a method for preparing polybutadiene, comprising adding 1,3-butadiene monomer and a catalyst in a molar ratio of 2000-10000:1 to an alkane solvent for polymerization to obtain a reaction solution; and condensing polybutadiene from the reaction solution using ethanol. The catalyst is prepared by mixing a rare earth compound, 1,3-butadiene monomer, alkyl aluminum hydride, and a molecular weight regulator to obtain a mixed solution, and then adding a chloride to the mixed solution to obtain the catalyst. Under suitable aging conditions, the order of addition of the molecular weight regulator has no effect on the polymerization effect.

[0024] This invention utilizes anionic coordination polymerization to prepare low molecular weight polybutadiene with high 1,4-structure content, and the polymerization environment is solution. The catalyst used in the preparation method of this invention is preferably a four-component homogeneous catalyst of rare earth compounds. The raw materials include rare earth compounds, alkyl aluminum hydride, a molecular weight regulator, chloride, and 1,3-butadiene monomer. The molecular weight regulator preferably uses C4-C10 alcohols or C4-C10 metal alcohols, more preferably tert-butanol, pentanol, hexanol, or potassium tert-butoxide. The rare earth compounds preferably use rare earth carboxylates or rare earth phosphates well-known in the art, more preferably rare earth phosphates. The rare earth carboxylates include, but are not limited to, neodymium neodecanoate, neodymium naphthenate, and neodymium isooctanoate. The rare earth phosphates include, but are not limited to, neodymium phosphate (P507) and neodymium phosphate (P204). The alkyl aluminum hydride is preferably diisobutylaluminum hydride, diethylaluminum hydride, or dialkylaluminum hydride well-known in the art. The chloride is preferably sesquiethylaluminum chloride, diisobutylaluminum chloride, diethylaluminum chloride, dichlorodimethylsilane, trimethylchlorosilane, trichloromethylsilane, silicon tetrachloride, dichlorodiphenylsilane, or trichlorosilane, which are well known to those skilled in the art.

[0025] Rare earth compounds, alkyl aluminum hydride, 1,3-butadiene monomer, and a molecular weight regulator are added to a reactor under nitrogen atmosphere. The preferred temperature is -20℃ to 50℃, and the preferred heating time is 10 min to 24 h. Then, chloride is added to the reactor, and the reactor is continued to be heated. The preferred temperature is 0℃ to 60℃, and the preferred time is 5 min to 60 min, to obtain a catalyst.

[0026] The catalyst provided by this invention is prepolymerized with a small amount of 1,3-butadiene monomer, which makes the catalyst the reactive center of polybutadiene and makes the reaction more stable.

[0027] After the catalyst is prepared, it is mixed with 1,3-butadiene monomer in an alkane solvent. The mass concentration of 1,3-butadiene monomer is preferably 10%-50%, and the molar ratio of catalyst to 1,3-butadiene monomer is 1:2000-10000. The alkane solvent is selected from hexane, cyclohexane, and heptane, which are well-known in the art; hexane is preferred in this invention. The hexane solution containing the catalyst and 1,3-butadiene monomer is subjected to a polymerization reaction at 0℃-80℃ for 2h-6h, more preferably 3h-5h. When it is necessary to stop the reaction, an ethanol solution containing 0.01g / mL-0.02g / mL of 2,6-di-tert-butyl-p-methylphenol is added to the hexane solution. Then, ethanol is added to condense the prepared product. After washing the product with ethanol, a colorless, odorless, transparent, and gel-free liquid is obtained, namely, low molecular weight polybutadiene with a high 1,4 molecular weight.

[0028] The following are specific embodiments of the present invention, which elaborate on the solution of the present invention in detail.

[0029] Example 1

[0030] Under nitrogen protection, neodymium phosphate (P507), 1,3-butadiene monomer, diisobutylaluminum hydrogenation, and potassium tert-butoxide were added sequentially to a dry catalyst reaction flask. The reaction was carried out at 50°C for 30 min, followed by the addition of sesquiethylaluminum chloride, and the reaction was carried out at 25°C for 30 min to obtain a rare earth catalyst for butadiene polymerization. The raw materials for catalyst preparation, neodymium phosphate (P507), 1,3-butadiene monomer, diisobutylaluminum hydrogenation, sesquiethylaluminum chloride, and potassium tert-butoxide, were prepared in a molar ratio of 1:10:50:2.0:3.0.

[0031] Under nitrogen protection, 80 ml of a hexane solution of 1,3-butadiene monomer was added to a dry 100 ml reaction flask. Then, the prepared rare earth catalyst was added. The molar ratio of catalyst to 1,3-butadiene monomer was 1:2000. Polymerization was carried out at 50 °C. After 4 hours of polymerization, the reaction was terminated with an ethanol solution containing 0.01 g / mL of antioxidant 264. Low molecular weight butadiene was obtained by condensation with ethanol.

[0032] The polybutadiene prepared in Example 1 was tested, and the microstructure was determined using the carbon disulfide coating method, preferably on a Bruker Vertex-70 FTIR spectrometer.

[0033] The molecular weight distribution of the polybutadiene prepared in this invention is preferably determined using gel permeation chromatography (515 HPLC pump and 2414 refractive index detector), specifically:

[0034] Four chromatographic columns (HMW 7, HMW 6E×2, HMW2) were used with tetrahydrofuran as the mobile phase. The test temperature was 30℃, the flow rate was 1.0 mL / min, and the solution concentration was 0.2–0.3 mg / 10 mL. The sample was filtered through a 0.45 μm filter before injection. The number-average molecular weight (Mn) and weight-average molecular weight (Mw) of the polymer were calculated using styrene as an internal standard. The molecular weight distribution of the polymer was characterized by the ratio of weight-average molecular weight to number-average molecular weight (Mn / Mw).

[0035] The yield of polybutadiene prepared in Example 1 was 100% as measured by the above method, with a number average molecular weight (Mn) of 4000 and a 1,4-structure content of 98.1%.

[0036] Comparative Example 2

[0037] Comparative Example 2 is a comparative example of Example 1. Under nitrogen protection, neodymium phosphate (P507), 1,3-butadiene monomer, and diisobutylaluminum hydrogenation were added sequentially to a dry catalyst reaction flask. After reacting at 50°C for 30 min, sesquiethylaluminum chloride was added, and the reaction was carried out at 25°C for 30 min to obtain a rare earth catalyst for butadiene polymerization. In the catalyst preparation raw materials, the molar ratio of neodymium phosphate (P507), 1,3-butadiene monomer, diisobutylaluminum hydrogenation, and sesquiethylaluminum chloride was 1:10:50:2.0.

[0038] Under nitrogen protection, 80 ml of a hexane solution of 1,3-butadiene monomer was added to a dry 100 ml reaction flask. Then, the prepared rare earth catalyst was added. The molar ratio of catalyst to 1,3-butadiene monomer was 1:2000. Polymerization was carried out at 50 °C. After 4 hours of polymerization, the reaction was terminated with an ethanol solution containing 0.01 g / mL of antioxidant 264. Low molecular weight butadiene was obtained by condensation with ethanol.

[0039] The polybutadiene prepared in this example was determined according to the method of Example 1. The results showed that the polymer yield was 100%, the number average molecular weight (Mn) was 7900, and the 1,4-structure content was 98.3%.

[0040] Example 3

[0041] Under nitrogen protection, neodymium phosphate (P507), 1,3-butadiene monomer, diisobutylaluminum hydrogenation, and potassium tert-butoxide were added sequentially to a dry catalyst reaction flask. The reaction was carried out at 50°C for 30 min, followed by the addition of dimethyldichlorosilane and a further reaction at 25°C for 30 min to obtain a rare earth catalyst for butadiene polymerization. The raw materials for catalyst preparation, neodymium phosphate (P507), 1,3-butadiene monomer, diisobutylaluminum hydrogenation, dimethyldichlorosilane, and potassium tert-butoxide, were prepared in a molar ratio of 1:10:50:2.0:3.0.

[0042] Under nitrogen protection, 80 ml of a hexane solution of 1,3-butadiene monomer was added to a dry 100 ml reaction flask. Then, the prepared rare earth catalyst was added. The molar ratio of catalyst to 1,3-butadiene monomer was 1:2000. Polymerization was carried out at 50 °C. After 4 hours of polymerization, the reaction was terminated with an ethanol solution containing 0.01 g / mL of antioxidant 264. Low molecular weight butadiene was obtained by condensation with ethanol.

[0043] The polybutadiene prepared in this example was determined according to the method of Example 1. The results showed that the polymer yield was 100%, the number average molecular weight (Mn) was 5600, and the 1,4-structure content was 97.4%.

[0044] Comparative Example 4

[0045] Comparative Example 4 is a comparative example of Example 3. Under nitrogen protection, neodymium phosphate (P507), 1,3-butadiene monomer, and diisobutylaluminum hydrogenation were added sequentially to a dry catalyst reaction flask. After reacting at 50°C for 30 min, dimethyldichlorosilane was added, and the reaction was carried out at 25°C for 30 min to obtain a rare earth catalyst for butadiene polymerization. In the catalyst preparation raw materials, the molar ratio of neodymium phosphate (P507), 1,3-butadiene monomer, diisobutylaluminum hydrogenation, and dimethyldichlorosilane was 1:10:50:2.0.

[0046] Under nitrogen protection, 80 ml of a hexane solution of 1,3-butadiene monomer was added to a dry 100 ml reaction flask. Then, the prepared rare earth catalyst was added. The molar ratio of catalyst to 1,3-butadiene monomer was 1:2000. Polymerization was carried out at 50 °C. After 4 hours of polymerization, the reaction was terminated with an ethanol solution containing 0.01 g / mL of antioxidant 264. Low molecular weight butadiene was obtained by condensation with ethanol.

[0047] The polybutadiene prepared in this example was measured according to the method of Example 1. The results showed that the polymer yield was 100%, the number average molecular weight (Mn) was 8200, and the 1,4-structure content was 98.1%.

[0048] Example 5

[0049] Under nitrogen protection, neodymium phosphate (P507), 1,3-butadiene monomer, diisobutylaluminum hydrogenation, and potassium tert-butoxide were added sequentially to a dry catalyst reaction flask. The reaction was carried out at 50°C for 30 min, followed by the addition of sesquiethylaluminum chloride, and the reaction was continued at 25°C for another 30 min to obtain a rare earth catalyst for butadiene polymerization. The raw materials for catalyst preparation, neodymium phosphate (P507), butadiene, diisobutylaluminum hydrogenation, sesquiethylaluminum chloride, and potassium tert-butoxide, were prepared in a molar ratio of 1:10:50:2.0:3.0.

[0050] Under nitrogen protection, 80 ml of a hexane solution of 1,3-butadiene monomer was added to a dry 100 ml reaction flask. Then, the prepared rare earth catalyst was added. The molar ratio of catalyst to 1,3-butadiene monomer was 1:2000. Polymerization was carried out at 0 °C. After 4 hours of polymerization, the reaction was terminated with an ethanol solution containing 0.01 g / mL of antioxidant 264. Low molecular weight butadiene was obtained by condensation with ethanol.

[0051] The polybutadiene prepared in this example was determined according to the method of Example 1. The results showed that the polymer yield was 92%, the number average molecular weight (Mn) was 7100, and the 1,4-structure content was 97.1%.

[0052] Example 6

[0053] Under nitrogen protection, neodymium phosphate (P507), 1,3-butadiene monomer, diisobutylaluminum hydrogenation, and potassium tert-butoxide were added sequentially to a dry catalyst reaction flask. The reaction was carried out at 50°C for 30 min, followed by the addition of sesquiethylaluminum chloride, and the reaction was carried out at 25°C for 30 min to obtain a rare earth catalyst for butadiene polymerization. The raw materials for catalyst preparation, neodymium phosphate (P507), 1,3-butadiene monomer, diisobutylaluminum hydrogenation, sesquiethylaluminum chloride, and potassium tert-butoxide, were prepared in a molar ratio of 1:10:50:2.0:3.0.

[0054] Under nitrogen protection, 80 ml of a hexane solution of 1,3-butadiene monomer was added to a dry 100 ml reaction flask. Then, the prepared rare earth catalyst was added. The molar ratio of catalyst to 1,3-butadiene monomer was 1:2000. Polymerization was carried out at 25 °C. After 4 hours of polymerization, the reaction was terminated with an ethanol solution containing 0.01 g / mL of antioxidant 264. Low molecular weight butadiene was obtained by condensation with ethanol.

[0055] The polybutadiene prepared in this example was determined according to the method of Example 1. The results showed that the polymer yield was 95%, the number average molecular weight (Mn) was 5900, and the 1,4-structure content was 98.0%.

[0056] Example 7

[0057] Under nitrogen protection, neodymium phosphate (P507), butadiene, diisobutylaluminum hydrogenation, and potassium tert-butoxide were added sequentially to a dry catalyst reaction flask. The reaction was carried out at 50°C for 30 min, followed by the addition of sesquiethylaluminum chloride, and then reacted at 25°C for another 30 min to obtain a rare earth catalyst for butadiene polymerization. The raw materials for catalyst preparation, neodymium phosphate (P507), butadiene, diisobutylaluminum hydrogenation, sesquiethylaluminum chloride, and potassium tert-butoxide, were prepared in a molar ratio of 1:10:30:2.0:3.0.

[0058] Under nitrogen protection, 80 ml of a hexane solution of 1,3-butadiene monomer was added to a dry 100 ml reaction flask. Then, the prepared rare earth catalyst was added. The molar ratio of catalyst to 1,3-butadiene monomer was 1:2000. Polymerization was carried out at 50 °C. After 4 hours of polymerization, the reaction was terminated with an ethanol solution containing 0.01 g / mL of antioxidant 264. Low molecular weight butadiene was obtained by condensation with ethanol.

[0059] The polybutadiene prepared in this example was determined according to the method of Example 1. The results showed that the polymer yield was 92%, the number average molecular weight (Mn) was 9800, and the 1,4-structure content was 97.8%.

[0060] Example 8

[0061] Under nitrogen protection, neodymium phosphate (P507), butadiene, diisobutylaluminum hydrogenation, and potassium tert-butoxide were added sequentially to a dry catalyst reaction flask. The reaction was carried out at 50°C for 30 min, followed by the addition of sesquiethylaluminum chloride, and then reacted at 25°C for another 30 min to obtain a rare earth catalyst for butadiene polymerization. The raw materials for catalyst preparation, neodymium phosphate (P507), butadiene, diisobutylaluminum hydrogenation, sesquiethylaluminum chloride, and potassium tert-butoxide, were prepared in a molar ratio of 1:10:10:2.0:3.0.

[0062] Under nitrogen protection, 80 ml of a hexane solution of 1,3-butadiene monomer was added to a dry 100 ml reaction flask. Then, the prepared rare earth catalyst was added. The molar ratio of catalyst to 1,3-butadiene monomer was 1:2000. Polymerization was carried out at 50 °C. After 4 hours of polymerization, the reaction was terminated with an ethanol solution containing 0.01 g / mL of antioxidant 264. Low molecular weight butadiene was obtained by condensation with ethanol.

[0063] The polybutadiene prepared in this example was determined according to the method of Example 1. The results showed that the polymer yield was 100%, the number average molecular weight (Mn) was 15800, and the 1,4-structure content was 98.1%.

[0064] Example 9

[0065] Under nitrogen protection, neodymium phosphate (P507), butadiene, diisobutylaluminum hydrogenation, and potassium tert-butoxide were added sequentially to a dry catalyst reaction flask. The reaction was carried out at 50°C for 30 min, followed by the addition of sesquiethylaluminum chloride, and then reacted at 25°C for another 30 min to obtain a rare earth catalyst for butadiene polymerization. The raw materials for catalyst preparation, neodymium phosphate (P507), butadiene, diisobutylaluminum hydrogenation, sesquiethylaluminum chloride, and potassium tert-butoxide, were prepared in a molar ratio of 1:10:80:2.0:3.0.

[0066] Under nitrogen protection, 80 ml of a hexane solution of 1,3-butadiene monomer was added to a dry 100 ml reaction flask. Then, the prepared rare earth catalyst was added. The molar ratio of catalyst to 1,3-butadiene monomer was 1:2000. Polymerization was carried out at 50 °C. After 4 hours of polymerization, the reaction was terminated with an ethanol solution containing 0.01 g / mL of antioxidant 264. Low molecular weight butadiene was obtained by condensation with ethanol.

[0067] The polybutadiene prepared in this example was measured according to the method of Example 1. The results showed that the polymer yield was 100%, the number average molecular weight (Mn) was 3100, and the 1,4-structure content was 97.0%.

[0068] Example 10

[0069] Under nitrogen protection, neodymium phosphate (P507), butadiene, diisobutylaluminum hydrogenation, and potassium tert-butoxide were added sequentially to a dry catalyst reaction flask. The reaction was carried out at 50°C for 30 min, followed by the addition of sesquiethylaluminum chloride, and then reacted at 25°C for 30 min to obtain a rare earth catalyst for butadiene polymerization. The raw materials for catalyst preparation, neodymium phosphate (P507), butadiene, diisobutylaluminum hydrogenation, sesquiethylaluminum chloride, and potassium tert-butoxide, were prepared in a molar ratio of 1:10:100:2.0:3.0.

[0070] Under nitrogen protection, 80 ml of a hexane solution of 1,3-butadiene monomer was added to a dry 100 ml reaction flask. Then, the prepared rare earth catalyst was added. The molar ratio of catalyst to 1,3-butadiene monomer was 1:2000. Polymerization was carried out at 50 °C. After 4 hours of polymerization, the reaction was terminated with an ethanol solution containing 0.01 g / mL of antioxidant 264. Low molecular weight butadiene was obtained by condensation with ethanol.

[0071] The polybutadiene prepared in this example was determined according to the method of Example 1. The results showed that the polymer yield was 100%, the number average molecular weight (Mn) was 2580, and the 1,4-structure content was 97.0%.

[0072] Example 11

[0073] Under nitrogen protection, neodymium phosphate (P507), butadiene, diisobutylaluminum hydrogenation, and potassium tert-butoxide were added sequentially to a dry catalyst reaction flask. The reaction was carried out at 50°C for 30 min, followed by the addition of sesquiethylaluminum chloride, and the reaction was continued at 25°C for another 30 min to obtain a rare earth catalyst for butadiene polymerization. The raw materials for catalyst preparation, neodymium phosphate (P507), butadiene, diisobutylaluminum hydrogenation, sesquiethylaluminum chloride, and potassium tert-butoxide, were prepared in a molar ratio of 1:10:50:1.0:3.0.

[0074] Under nitrogen protection, 80 ml of a hexane solution of 1,3-butadiene monomer was added to a dry 100 ml reaction flask. Then, the prepared rare earth catalyst was added. The molar ratio of catalyst to 1,3-butadiene monomer was 1:2000. Polymerization was carried out at 50 °C. After 4 hours of polymerization, the reaction was terminated with an ethanol solution containing 0.01 g / mL of antioxidant 264. Low molecular weight butadiene was obtained by condensation with ethanol.

[0075] The polybutadiene prepared in this example was measured according to the method of Example 1. The results showed that the polymer yield was 100%, the number average molecular weight (Mn) was 6800, and the 1,4-structure content was 97.8%.

[0076] Example 12

[0077] Under nitrogen protection, neodymium phosphate (P507), butadiene, diisobutylaluminum hydrogenation, and potassium tert-butoxide were added sequentially to a dry catalyst reaction flask. The reaction was carried out at 50°C for 30 min, followed by the addition of sesquiethylaluminum chloride, and then reacted at 25°C for 30 min to obtain a rare earth catalyst for butadiene polymerization. The raw materials for catalyst preparation, neodymium phosphate (P507), butadiene, diisobutylaluminum hydrogenation, sesquiethylaluminum chloride, and potassium tert-butoxide, were prepared in a molar ratio of 1:10:50:4.0:3.0.

[0078] Under nitrogen protection, 80 ml of a hexane solution of 1,3-butadiene monomer was added to a dry 100 ml reaction flask. Then, the prepared rare earth catalyst was added. The molar ratio of catalyst to 1,3-butadiene monomer was 1:2000. Polymerization was carried out at 50 °C. After 4 hours of polymerization, the reaction was terminated with an ethanol solution containing 0.01 g / mL of antioxidant 264. Low molecular weight butadiene was obtained by condensation with ethanol.

[0079] The polybutadiene prepared in this example was determined according to the method of Example 1. The results showed that the polymer yield was 90%, the number average molecular weight (Mn) was 5100, and the 1,4-structure content was 97.5%.

[0080] Example 13

[0081] Under nitrogen protection, neodymium phosphate (P507), butadiene, diisobutylaluminum hydrogenation, and potassium tert-butoxide were added sequentially to a dry catalyst reaction flask. The reaction was carried out at 50°C for 30 min, followed by the addition of sesquiethylaluminum chloride, and then reacted at 25°C for another 30 min to obtain a rare earth catalyst for butadiene polymerization. The raw materials for catalyst preparation, neodymium phosphate (P507), butadiene, diisobutylaluminum hydrogenation, sesquiethylaluminum chloride, and potassium tert-butoxide, were prepared in a molar ratio of 1:10:50:5.0:3.0.

[0082] Under nitrogen protection, 80 ml of a hexane solution of 1,3-butadiene monomer was added to a dry 100 ml reaction flask. Then, the prepared rare earth catalyst was added. The molar ratio of catalyst to 1,3-butadiene monomer was 1:2000. Polymerization was carried out at 50 °C. After 4 hours of polymerization, the reaction was terminated with an ethanol solution containing 0.01 g / mL of antioxidant 264. Low molecular weight butadiene was obtained by condensation with ethanol.

[0083] The polybutadiene prepared in this example was determined according to the method of Example 1. The results showed that the polymer yield was 86%, the number average molecular weight (Mn) was 4900, and the 1,4-structure content was 97.3%.

[0084] Example 14

[0085] Under nitrogen protection, neodymium phosphate (P507), butadiene, diisobutylaluminum hydrogenation, and potassium tert-butoxide were added sequentially to a dry catalyst reaction flask. The reaction was carried out at 50°C for 30 min, followed by the addition of sesquiethylaluminum chloride, and then reacted at 25°C for another 30 min to obtain a rare earth catalyst for butadiene polymerization. The raw materials for catalyst preparation, neodymium phosphate (P507), butadiene, diisobutylaluminum hydrogenation, sesquiethylaluminum chloride, and potassium tert-butoxide, were prepared in a molar ratio of 1:5:50:2.0:3.0.

[0086] Under nitrogen protection, 80 ml of a hexane solution of 1,3-butadiene monomer was added to a dry 100 ml reaction flask. Then, the prepared rare earth catalyst was added. The molar ratio of catalyst to 1,3-butadiene monomer was 1:2000. Polymerization was carried out at 50 °C. After 4 hours of polymerization, the reaction was terminated with an ethanol solution containing 0.01 g / mL of antioxidant 264. Low molecular weight butadiene was obtained by condensation with ethanol.

[0087] The polybutadiene prepared in this example was determined according to the method of Example 1. The results showed that the polymer yield was 100%, the number average molecular weight (Mn) was 4100, and the 1,4-structure content was 98.0%.

[0088] Example 15

[0089] Under nitrogen protection, neodymium phosphate (P507), butadiene, diisobutylaluminum hydrogenation, and potassium tert-butoxide were added sequentially to a dry catalyst reaction flask. The reaction was carried out at 50°C for 30 min, followed by the addition of sesquiethylaluminum chloride, and then reacted at 25°C for another 30 min to obtain a rare earth catalyst for butadiene polymerization. The raw materials for catalyst preparation, neodymium phosphate (P507), butadiene, diisobutylaluminum hydrogenation, sesquiethylaluminum chloride, and potassium tert-butoxide, were prepared in a molar ratio of 1:50:50:2.0:3.0.

[0090] Under nitrogen protection, 80 ml of a hexane solution of 1,3-butadiene monomer was added to a dry 100 ml reaction flask. Then, the prepared rare earth catalyst was added. The molar ratio of catalyst to 1,3-butadiene monomer was 1:2000. Polymerization was carried out at 50 °C. After 4 hours of polymerization, the reaction was terminated with an ethanol solution containing 0.01 g / mL of antioxidant 264. Low molecular weight butadiene was obtained by condensation with ethanol.

[0091] The polybutadiene prepared in this example was determined according to the method of Example 1. The results showed that the polymer yield was 100%, the number average molecular weight (Mn) was 4150, and the 1,4-structure content was 98.2%.

[0092] Example 16

[0093] Under nitrogen protection, neodymium phosphate (P507), butadiene, diisobutylaluminum hydrogenation, and potassium tert-butoxide were added sequentially to a dry catalyst reaction flask. The reaction was carried out at 50°C for 30 min, followed by the addition of sesquiethylaluminum chloride, and then reacted at 25°C for another 30 min to obtain a rare earth catalyst for butadiene polymerization. The raw materials for catalyst preparation, neodymium phosphate (P507), butadiene, diisobutylaluminum hydrogenation, sesquiethylaluminum chloride, and potassium tert-butoxide, were prepared in a molar ratio of 1:100:50:2.0:3.0.

[0094] Under nitrogen protection, 80 ml of a hexane solution of 1,3-butadiene monomer was added to a dry 100 ml reaction flask. Then, the prepared rare earth catalyst was added. The molar ratio of catalyst to 1,3-butadiene monomer was 1:2000. Polymerization was carried out at 50 °C. After 4 hours of polymerization, the reaction was terminated with an ethanol solution containing 0.01 g / mL of antioxidant 264. Low molecular weight butadiene was obtained by condensation with ethanol.

[0095] The polybutadiene prepared in this example was determined according to the method of Example 1. The results showed that the polymer yield was 100%, the number average molecular weight (Mn) was 4250, and the 1,4-structure content was 98.1%.

[0096] Example 17

[0097] Under nitrogen protection, neodymium phosphate (P507), butadiene, diisobutylaluminum hydrogenation, and potassium tert-butoxide were added sequentially to a dry catalyst reaction flask. The reaction was carried out at 50°C for 30 min, followed by the addition of sesquiethylaluminum chloride, and then reacted at 25°C for another 30 min to obtain a rare earth catalyst for butadiene polymerization. The raw materials for catalyst preparation, neodymium phosphate (P507), butadiene, diisobutylaluminum hydrogenation, sesquiethylaluminum chloride, and potassium tert-butoxide, were prepared in a molar ratio of 1:10:50:2.0:1.0.

[0098] Under nitrogen protection, 80 ml of a hexane solution of 1,3-butadiene monomer was added to a dry 100 ml reaction flask. Then, the prepared rare earth catalyst was added. The molar ratio of catalyst to 1,3-butadiene monomer was 1:2000. Polymerization was carried out at 50 °C. After 4 hours of polymerization, the reaction was terminated with an ethanol solution containing 0.01 g / mL of antioxidant 264. Low molecular weight butadiene was obtained by condensation with ethanol.

[0099] The polybutadiene prepared in this example was measured according to the method of Example 1. The results showed that the polymer yield was 100%, the number average molecular weight (Mn) was 6400, and the 1,4-structure content was 98.3%.

[0100] Example 18

[0101] Under nitrogen protection, neodymium phosphate (P507), butadiene, diisobutylaluminum hydrogenation, and potassium tert-butoxide were added sequentially to a dry catalyst reaction flask. The reaction was carried out at 50°C for 30 min, followed by the addition of sesquiethylaluminum chloride, and then reacted at 25°C for another 30 min to obtain a rare earth catalyst for butadiene polymerization. The raw materials for catalyst preparation, neodymium phosphate (P507), butadiene, diisobutylaluminum hydrogenation, sesquiethylaluminum chloride, and potassium tert-butoxide, were prepared in a molar ratio of 1:10:50:2.0:10.0.

[0102] Under nitrogen protection, 80 ml of a hexane solution of 1,3-butadiene monomer was added to a dry 100 ml reaction flask. Then, the prepared rare earth catalyst was added. The molar ratio of catalyst to 1,3-butadiene monomer was 1:2000. Polymerization was carried out at 50 °C. After 4 hours of polymerization, the reaction was terminated with an ethanol solution containing 0.01 g / mL of antioxidant 264. Low molecular weight butadiene was obtained by condensation with ethanol.

[0103] The polybutadiene prepared in this example was determined according to the method of Example 1. The results showed that the polymer yield was 92%, the number average molecular weight (Mn) was 4550, and the 1,4-structure content was 97.8%.

[0104] Example 19

[0105] Under nitrogen protection, neodymium phosphate (P507), butadiene, diisobutylaluminum hydrogenation, and potassium tert-butoxide were added sequentially to a dry catalyst reaction flask. The reaction was carried out at 50°C for 30 min, followed by the addition of sesquiethylaluminum chloride, and then reacted at 25°C for another 30 min to obtain a rare earth catalyst for butadiene polymerization. The raw materials for catalyst preparation, neodymium phosphate (P507), butadiene, diisobutylaluminum hydrogenation, sesquiethylaluminum chloride, and potassium tert-butoxide, were prepared in a molar ratio of 1:10:50:2.0:3.0.

[0106] Under nitrogen protection, 80 ml of a hexane solution of 1,3-butadiene monomer was added to a dry 100 ml reaction flask. Then, the prepared rare earth catalyst was added. The molar ratio of catalyst to 1,3-butadiene monomer was 1:5000. Polymerization was carried out at 50 °C. After 4 hours of polymerization, the reaction was terminated with an ethanol solution containing 0.01 g / mL of antioxidant 264. Low molecular weight butadiene was obtained by condensation with ethanol.

[0107] The polybutadiene prepared in this example was determined according to the method of Example 1. The results showed that the polymer yield was 96%, the number average molecular weight (Mn) was 9600, and the 1,4-structure content was 97.9%.

[0108] Example 20

[0109] Under nitrogen protection, neodymium phosphate (P507), butadiene, diisobutylaluminum hydrogenation, and potassium tert-butoxide were added sequentially to a dry catalyst reaction flask. The reaction was carried out at 50°C for 30 min, followed by the addition of sesquiethylaluminum chloride, and then reacted at 25°C for another 30 min to obtain a rare earth catalyst for butadiene polymerization. The raw materials for catalyst preparation, neodymium phosphate (P507), butadiene, diisobutylaluminum hydrogenation, sesquiethylaluminum chloride, and potassium tert-butoxide, were prepared in a molar ratio of 1:10:50:2.0:3.0.

[0110] Under nitrogen protection, 80 ml of a hexane solution of 1,3-butadiene monomer was added to a dry 100 ml reaction flask. Then, the prepared rare earth catalyst was added. The molar ratio of catalyst to 1,3-butadiene monomer was 1:10000. Polymerization was carried out at 50 °C. After 4 hours of polymerization, the reaction was terminated with an ethanol solution containing 0.01 g / mL of antioxidant 264. Low molecular weight butadiene was obtained by condensation with ethanol.

[0111] The polybutadiene prepared in this example was determined according to the method of Example 1. The results showed that the polymer yield was 93%, the number average molecular weight (Mn) was 14,500, and the 1,4-structure content was 98.2%.

[0112] Example 21

[0113] Under nitrogen protection, neodymium phosphate (P507), butadiene, diisobutylaluminum hydrogenation, and potassium tert-butoxide were added sequentially to a dry catalyst reaction flask. The reaction was carried out at 50°C for 10 min, followed by the addition of sesquiethylaluminum chloride, and the reaction was carried out at 25°C for 30 min to obtain a rare earth catalyst for butadiene polymerization. The raw materials for catalyst preparation, neodymium phosphate (P507), butadiene, diisobutylaluminum hydrogenation, sesquiethylaluminum chloride, and potassium tert-butoxide, were prepared in a molar ratio of 1:10:50:2.0:3.0.

[0114] Under nitrogen protection, 80 ml of a hexane solution of 1,3-butadiene monomer was added to a dry 100 ml reaction flask. Then, the prepared rare earth catalyst was added. The molar ratio of catalyst to 1,3-butadiene monomer was 1:2000. Polymerization was carried out at 50 °C. After 4 hours of polymerization, the reaction was terminated with an ethanol solution containing 0.01 g / mL of antioxidant 264. Low molecular weight butadiene was obtained by condensation with ethanol.

[0115] The polybutadiene prepared in this example was determined according to the method of Example 1. The results showed that the polymer yield was 98%, the number average molecular weight (Mn) was 4600, and the 1,4-structure content was 98.0%.

[0116] Example 22

[0117] Under nitrogen protection, neodymium phosphate (P507), butadiene, diisobutylaluminum hydrogenation, and potassium tert-butoxide were added sequentially to a dry catalyst reaction flask. The reaction was carried out at -20°C for 30 min, followed by the addition of sesquiethylaluminum chloride, and then reacted at 25°C for another 30 min to obtain a rare earth catalyst for butadiene polymerization. The raw materials for catalyst preparation, neodymium phosphate (P507), butadiene, diisobutylaluminum hydrogenation, sesquiethylaluminum chloride, and potassium tert-butoxide, were prepared in a molar ratio of 1:10:50:2.0:3.0.

[0118] Under nitrogen protection, 80 ml of a hexane solution of 1,3-butadiene monomer was added to a dry 100 ml reaction flask. Then, the prepared rare earth catalyst was added. The molar ratio of catalyst to 1,3-butadiene monomer was 1:2000. Polymerization was carried out at 50 °C. After 4 hours of polymerization, the reaction was terminated with an ethanol solution containing 0.01 g / mL of antioxidant 264. Low molecular weight butadiene was obtained by condensation with ethanol.

[0119] The polybutadiene prepared in this example was determined according to the method of Example 1. The results showed that the polymer yield was 95%, the number average molecular weight (Mn) was 2800, and the 1,4-structure content was 98.1%.

[0120] Example 23

[0121] Under nitrogen protection, neodymium phosphate (P507), butadiene, diisobutylaluminum hydrogenation, and potassium tert-butoxide were added sequentially to a dry catalyst reaction flask. The reaction was carried out at -20°C for 24 hours, followed by the addition of sesquiethylaluminum chloride, and the reaction was carried out at 0°C for 30 minutes to obtain a rare earth catalyst for butadiene polymerization. The raw materials for catalyst preparation, neodymium phosphate (P507), butadiene, diisobutylaluminum hydrogenation, sesquiethylaluminum chloride, and potassium tert-butoxide, were prepared in a molar ratio of 1:10:100:2.0:4.0.

[0122] Under nitrogen protection, 80 ml of a hexane solution of 1,3-butadiene monomer was added to a dry 100 ml reaction flask. Then, the prepared rare earth catalyst was added. The molar ratio of catalyst to 1,3-butadiene monomer was 1:2000. Polymerization was carried out at 50 °C. After 4 hours of polymerization, the reaction was terminated with an ethanol solution containing 0.01 g / mL of antioxidant 264. Low molecular weight butadiene was obtained by condensation with ethanol.

[0123] The polybutadiene prepared in this example was determined according to the method of Example 1. The results showed that the polymer yield was 94%, the number average molecular weight (Mn) was 1900, and the 1,4-structure content was 97.2%.

[0124] Example 24

[0125] Under nitrogen protection, neodymium phosphate (P507), butadiene, diisobutylaluminum hydrogenation, and potassium tert-butoxide were added sequentially to a dry catalyst reaction flask, and the reaction was carried out at -20°C for 24 h. Then, sesquiethylaluminum chloride was added, and the reaction was carried out at 25°C for 30 min to obtain a rare earth catalyst for butadiene polymerization. In the preparation of the catalyst raw materials, the molar ratio of neodymium phosphate (P507), butadiene, diisobutylaluminum hydrogenation, sesquiethylaluminum chloride, and potassium tert-butoxide was 1:10:50:2.0:3.0.

[0126] Under nitrogen protection, 80 ml of a hexane solution of 1,3-butadiene monomer was added to a dry 100 ml reaction flask. Then, the prepared rare earth catalyst was added. The molar ratio of catalyst to 1,3-butadiene monomer was 1:2000. Polymerization was carried out at 50 °C. After 4 hours of polymerization, the reaction was terminated with an ethanol solution containing 0.01 g / mL of antioxidant 264. Low molecular weight butadiene was obtained by condensation with ethanol.

[0127] The polybutadiene prepared in this example was determined according to the method of Example 1. The results showed that the polymer yield was 93%, the number average molecular weight (Mn) was 3200, and the 1,4-structure content was 97.9%.

[0128] Example 25

[0129] Under nitrogen protection, neodymium phosphate (P507), butadiene, diisobutylaluminum hydrogenation, and tert-butanol were added sequentially to a dry catalyst reaction flask, and the reaction was carried out at 50°C for 30 min. Then, sesquiethylaluminum chloride was added, and the reaction was carried out at 25°C for 30 min to obtain a rare earth catalyst for butadiene polymerization. In the preparation of the catalyst, the molar ratio of neodymium phosphate (P507), butadiene, diisobutylaluminum hydrogenation, sesquiethylaluminum chloride, and tert-butanol was 1:10:50:2.0:3.0.

[0130] Under nitrogen protection, 80 ml of a hexane solution of 1,3-butadiene monomer was added to a dry 100 ml reaction flask. Then, the prepared rare earth catalyst was added. The molar ratio of catalyst to 1,3-butadiene monomer was 1:2000. Polymerization was carried out at 50 °C. After 4 hours of polymerization, the reaction was terminated with an ethanol solution containing 0.01 g / mL of antioxidant 264. Low molecular weight butadiene was obtained by condensation with ethanol.

[0131] The polybutadiene prepared in this example was determined according to the method of Example 1. The results showed that the polymer yield was 98%, the number average molecular weight (Mn) was 4800, and the 1,4-structure content was 98.0%.

[0132] Example 26

[0133] Under nitrogen protection, neodymium phosphate (P507), butadiene, diisobutylaluminum hydrogenation, and pentanol were added sequentially to a dry catalyst reaction flask, and the reaction was carried out at 50°C for 30 min. Then, sesquiethylaluminum chloride was added, and the reaction was carried out at 25°C for 30 min to obtain a rare earth catalyst for butadiene polymerization. In the catalyst preparation, the molar ratio of neodymium phosphate (P507), butadiene, diisobutylaluminum hydrogenation, sesquiethylaluminum chloride, and pentanol was 1:10:50:2.0:3.0.

[0134] Under nitrogen protection, 80 ml of a hexane solution of 1,3-butadiene monomer was added to a dry 100 ml reaction flask. Then, the prepared rare earth catalyst was added. The molar ratio of catalyst to 1,3-butadiene monomer was 1:2000. Polymerization was carried out at 50 °C. After 4 hours of polymerization, the reaction was terminated with an ethanol solution containing 0.01 g / mL of antioxidant 264. Low molecular weight butadiene was obtained by condensation with ethanol.

[0135] The polybutadiene prepared in this example was determined according to the method of Example 1. The results showed that the polymer yield was 92%, the number average molecular weight (Mn) was 5300, and the 1,4-structure content was 97.7%.

[0136] Example 27

[0137] Under nitrogen protection, neodymium neodecanoate, butadiene, diisobutylaluminum hydrogenation, and potassium tert-butoxide were added sequentially to a dry catalyst reaction flask. The reaction was carried out at 50°C for 30 min, followed by the addition of sesquiethylaluminum chloride, and the reaction was carried out at 25°C for 30 min to obtain a rare earth catalyst for butadiene polymerization. The molar ratio of neodymium neodecanoate, butadiene, diisobutylaluminum hydrogenation, sesquiethylaluminum chloride, and potassium tert-butoxide in the catalyst preparation raw materials was 1:10:50:2.0:3.0.

[0138] Under nitrogen protection, 80 ml of a hexane solution of 1,3-butadiene monomer was added to a dry 100 ml reaction flask. Then, the prepared rare earth catalyst was added. The molar ratio of catalyst to 1,3-butadiene monomer was 1:2000. Polymerization was carried out at 50 °C. After 4 hours of polymerization, the reaction was terminated with an ethanol solution containing 0.01 g / mL of antioxidant 264. Low molecular weight butadiene was obtained by condensation with ethanol.

[0139] The polybutadiene prepared in this example was determined according to the method of Example 1. The results showed that the polymer yield was 100%, the number average molecular weight (Mn) was 4600, and the 1,4-structure content was 98.4%.

[0140] Example 28

[0141] Under nitrogen protection, neodymium neodecanoate, butadiene, diisobutylaluminum hydrogenation, and potassium tert-butoxide were added sequentially to a dry catalyst reaction flask. The reaction was carried out at 50°C for 30 min, followed by the addition of sesquiethylaluminum chloride, and the reaction was carried out at 25°C for 30 min to obtain a rare earth catalyst for butadiene polymerization. The molar ratio of neodymium neodecanoate, butadiene, diisobutylaluminum hydrogenation, sesquiethylaluminum chloride, and potassium tert-butoxide in the catalyst preparation raw materials was 1:10:50:2.0:3.0.

[0142] Under nitrogen protection, 80 ml of a hexane solution of 1,3-butadiene monomer was added to a dry 100 ml reaction flask. Then, the prepared rare earth catalyst was added. The molar ratio of catalyst to 1,3-butadiene monomer was 1:5000. Polymerization was carried out at 50 °C. After 4 hours of polymerization, the reaction was terminated with an ethanol solution containing 0.01 g / mL of antioxidant 264. Low molecular weight butadiene was obtained by condensation with ethanol.

[0143] The polybutadiene prepared in this example was determined according to the method of Example 1. The results showed that the polymer yield was 95%, the number average molecular weight (Mn) was 9900, and the 1,4-structure content was 98.2%.

[0144] Example 29

[0145] Under nitrogen protection, neodymium isooctanoate, butadiene, diisobutylaluminum hydrogenation, and potassium tert-butoxide were added sequentially to a dry catalyst reaction flask. The reaction was carried out at 50°C for 30 min, followed by the addition of sesquiethylaluminum chloride, and the reaction was carried out at 25°C for 30 min to obtain a rare earth catalyst for butadiene polymerization. The molar ratio of neodymium isooctanoate, butadiene, diisobutylaluminum hydrogenation, sesquiethylaluminum chloride, and potassium tert-butoxide in the catalyst preparation raw materials was 1:10:50:2.0:3.0.

[0146] Under nitrogen protection, 80 ml of a hexane solution of 1,3-butadiene monomer was added to a dry 100 ml reaction flask. Then, the prepared rare earth catalyst was added. The molar ratio of catalyst to 1,3-butadiene monomer was 1:2000. Polymerization was carried out at 50 °C. After 4 hours of polymerization, the reaction was terminated with an ethanol solution containing 0.01 g / mL of antioxidant 264. Low molecular weight butadiene was obtained by condensation with ethanol.

[0147] The polybutadiene prepared in this example was determined according to the method of Example 1. The results showed that the polymer yield was 93%, the number average molecular weight (Mn) was 5600, and the 1,4-structure content was 98.0%.

[0148] Example 30

[0149] Under nitrogen protection, neodymium naphthenate, butadiene, diisobutylaluminum hydrogenation, and potassium tert-butoxide were added sequentially to a dry catalyst reaction flask. The reaction was carried out at 50°C for 30 min, followed by the addition of sesquiethylaluminum chloride, and the reaction was continued at 25°C for 30 min to obtain a rare earth catalyst for butadiene polymerization. The molar ratio of neodymium naphthenate, butadiene, diisobutylaluminum hydrogenation, sesquiethylaluminum chloride, and potassium tert-butoxide in the catalyst preparation raw materials was 1:10:50:2.0:3.0.

[0150] Under nitrogen protection, 80 ml of a hexane solution of 1,3-butadiene monomer was added to a dry 100 ml reaction flask. Then, the prepared rare earth catalyst was added. The molar ratio of catalyst to 1,3-butadiene monomer was 1:2000. Polymerization was carried out at 50 °C. After 4 hours of polymerization, the reaction was terminated with an ethanol solution containing 0.01 g / mL of antioxidant 264. Low molecular weight butadiene was obtained by condensation with ethanol.

[0151] The polybutadiene prepared in this example was determined according to the method of Example 1. The results showed that the polymer yield was 87%, the number average molecular weight (Mn) was 5900, and the 1,4-structure content was 97.8%.

[0152] Example 31

[0153] Under nitrogen protection, neodymium phosphate (P507), butadiene, diisobutylaluminum hydrogenation, and potassium tert-butoxide were added sequentially to a dry catalyst reaction flask. The reaction was carried out at 50°C for 30 min, followed by the addition of sesquiethylaluminum chloride, and the reaction was continued at 25°C for another 30 min to obtain a rare earth catalyst for butadiene polymerization. The molar ratio of neodymium phosphate (P507), butadiene, diisobutylaluminum hydrogenation, sesquiethylaluminum chloride, and potassium tert-butoxide in the catalyst preparation raw materials was 1:10:50:2.0:3.0.

[0154] Under nitrogen protection, a hexane solution of 1,3-butadiene monomer (molar ratio of 1,3-butadiene monomer to hexane) was added to a 5L reactor. The polymerization reaction was initiated by adding a catalyst while stirring at 50°C. The molar ratio of catalyst to 1,3-butadiene monomer was 1:2000. The polymerization reaction proceeded smoothly. After 4 hours, the polymerization was terminated with an ethanol solution containing 0.01 g / mL antioxidant 264. The polymer was then precipitated in ethanol, washed with ethanol, and low molecular weight polybutadiene was obtained.

[0155] The polybutadiene prepared in this example was determined according to the method of Example 1, and the results showed that the polymer yield was 95%, the number average molecular weight was 5200, and the 1,4-structure content was 97.5%.

[0156] As can be seen from the above embodiments, the polybutadiene prepared by the present invention has a low molecular weight and a high 1,4-structure content, wherein the molecular weight of the polybutadiene is 1000 to 10000 and the 1,4-structure content is greater than 95%.

[0157] It is understood that the above specific description of the present invention is only for illustrating the present invention and is not limited to the technical solutions described in the embodiments of the present invention. Those skilled in the art should understand that modifications or equivalent substitutions can still be made to the present invention to achieve the same technical effect; as long as the use needs are met, they are all within the protection scope of the present invention.

Claims

1. A method for preparing polybutadiene, characterized in that: The steps of this method are as follows: Step 1: Add 1,3-butadiene monomer and catalyst to an alkane solvent at a molar ratio of (5000~10000):1 to carry out polymerization reaction to obtain a reaction solution; Step 2: Polybutadiene is condensed from the above reaction solution using ethanol; The catalyst is prepared by mixing rare earth compounds, alkyl aluminum hydride, 1,3-butadiene monomer, and molecular weight regulator, and reacting them at -20℃ to 50℃ for 10 min to 24 h to obtain a mixed solution. Then, chloride is added to the mixed solution and reacted at 0 to 60℃ for 5 min to 60 min to obtain the catalyst. The molar ratio of the rare earth compound: alkyl aluminum hydride: chloride: 1,3-butadiene monomer: molecular weight regulator is 1:10~100:1~5:5~100:1~10; The molecular weight regulator is potassium tert-butoxide.

2. The method for preparing polybutadiene according to claim 1, characterized in that: Step one further includes adding an ethanol solution of 2,6-di-tert-butyl-p-methylphenol to the reaction solution.

3. The method for preparing polybutadiene according to claim 2, characterized in that: The mass concentration of the 2,6-di-tert-butyl-p-methylphenol is 1%~2% g / ml.

4. The method for preparing polybutadiene according to claim 1, characterized in that: The rare earth compound is one or more rare earth carboxylates and rare earth phosphates.

5. The method for preparing polybutadiene according to claim 4, characterized in that: The rare earth carboxylate is one or more of neodymium neodecanoate, neodymium naphthenate, and neodymium isooctanoate, and the rare earth phosphate is neodymium phosphate.

6. The method for preparing polybutadiene according to claim 1, characterized in that: The chloride is sesquiethylaluminum chloride, diisobutylaluminum chloride, diethylaluminum chloride, dichlorodimethylsilane, trimethylchlorosilane, trichloromethylsilane, silicon tetrachloride, dichlorodiphenylsilane, or trichlorosilane.

7. The method for preparing polybutadiene according to claim 1, characterized in that: The alkyl aluminum hydride is diisobutylaluminum hydride or diethylaluminum hydride.

8. The method for preparing polybutadiene according to claim 1, characterized in that: The alkane solvent is hexane, cyclohexane, or heptane.