A Co-CFA-1-based butadiene polymerization catalyst, its preparation and application

Abstract

This invention discloses a Co-CFA-1-based butadiene polymerization catalyst and its preparation method. The butadiene polymerization catalyst comprises Co-CFA-1, a co-catalyst, and toluene solvent. The Co-CFA-1 is prepared by heating a dispersion of CFA-1 and cobalt acetate tetrahydrate in NMF at 55–65°C for 18–30 hours, followed by filtration, washing, and vacuum drying to obtain Co-CFA-1. The co-catalyst is composed of alkylaluminum and methylaluminoxane, wherein the alkylaluminum is selected from at least one of diethylaluminum chloride, triisobutylaluminum, and diethylaluminum chloride. This invention provides the application of the Co-CFA-1-based butadiene polymerization catalyst in the preparation of cis-polybutadiene, which can produce high-quality polybutadiene rubber products with high cis-structure content, controllable molecular weight, and narrow molecular weight distribution, and the product yield is high.

Description

Technical Field

[0001] This invention relates to a Co-CFA-1-based butadiene polymerization catalyst, its preparation, and its application. Technical Background

[0002] Butadiene rubber (BR), also known as cis-1,4 polybutadiene rubber, has the molecular formula (C4H6). n Butadiene rubber is a structurally regular synthetic rubber obtained by polymerizing butadiene. Its molecular chain is mainly composed of cis-1,4-structural units. Cis-butadiene rubber is a general-purpose synthetic rubber synthesized from butadiene using different catalysts and polymerization methods.

[0003] The production process of butadiene rubber uses different catalyst systems and formulations, such as nickel-based, titanium-based, cobalt-based, lithium-based, and rare earth neodymium-based catalysts. These different catalyst systems and formulations are the key to the production of butadiene rubber, as they determine the microstructure of the polymer and the properties of the rubber.

[0004] Butadiene is an important organic chemical raw material, widely used in the production of synthetic rubber, plastics, nylon, and other polymer materials. With the continuous development of industrial technology, higher demands are being placed on the yield, purity, and production efficiency of butadiene polymerization. Therefore, optimizing and innovating butadiene experiments has significant practical and economic value.

[0005] In recent years, metal-organic frameworks (MOFs) have emerged as a rapidly developing class of coordination polymers. MOFs possess unique three-dimensional porous structures and have attracted widespread attention in the field of single-center heterogeneous catalysis. Due to their singular dispersion and specific transition metal coordination environments, MOF materials exhibit unique advantages in heterogeneous catalysis. Furthermore, secondary building units (SBUs) can facilitate the exchange of small molecules such as transition metals on solid supports. Many SBUs can also modify their local coordination structures through cation exchange, thereby controlling their coordination configuration.

[0006] In our butadiene experiments, we employed a novel catalyst exhibiting high activity and selectivity, effectively promoting the butadiene synthesis reaction. Compared to traditional catalysts, the novel catalyst demonstrated significant advantages in increasing yield and reducing side reactions.

[0007] Metzger ED, Comito RJ, WU Z, et al. Highly Selective Heterogeneous Ethylene Dimerization with a Scalable and Chemically Robust MOF Catalyst[J].ACS Sustainable Chemistry & Engineering, 2019, 7(7): 6654-61. This paper reports the role of cation exchange of Co-MFU-4l and Ni-MFU-4l in ethylene polymerization, but these methods are less effective in butadiene polymerization.

[0008] CFA-1 (Zn5(OAc)4(bibta)3) is a rigid metal-organic framework material with Zn as the metal center and H2BTDD as the organic ligand. It has good hydrothermal and chemical stability. Furthermore, SBU can change its local coordination structure through cation exchange. Co ions can be exchanged into CFA-1 through ion exchange and coordination to obtain the cobalt-based catalyst Co-CFA-1. Cobalt-based catalysts have great potential for preparing high-cis, high-molecular-weight, and narrow-molecular-weight polybutadiene rubber. Summary of the Invention

[0009] The purpose of this invention is to provide a butadiene polymerization catalyst based on Co-CFA-1, its preparation and application. This catalyst has the characteristics of simple synthesis, high catalytic activity and high cis structure, and can achieve high-quality polybutadiene products with high cis structure, high molecular weight and narrow molecular weight distribution.

[0010] To achieve the above-mentioned objectives, the present invention adopts the following technical solution:

[0011] In a first aspect, the present invention provides a butadiene polymerization catalyst based on Co-CFA-1, the butadiene polymerization catalyst comprising Co-CFA-1, a co-catalyst and toluene solvent, wherein the molar ratio of aluminum in the co-catalyst to cobalt in Co-CFA-1 is 20 to 300:1.

[0012] Co-CFA-1 was prepared by the following method: CFA-1 and NMF dispersion of cobalt acetate tetrahydrate were heated at 55-65°C for 18-30 hours, and then filtered, washed and vacuum dried to obtain Co-CFA-1.

[0013] The co-catalyst is composed of alkylaluminum and methylaluminoxane in a molar ratio of 2 to 5:1, wherein the alkylaluminum is selected from at least one of diethylaluminum chloride, triisobutylaluminum and diethylaluminum chloride.

[0014] Preferably, the mass ratio of CFA-1 to cobalt acetate tetrahydrate is 0.06–0.12:1.2–1.8; more preferably, it is 0.07–0.10:1.3–1.7.

[0015] Preferably, the mass-to-volume ratio of CFA-1 to NMF is 1g:350-420mL.

[0016] Preferably, methanol is used as the washing agent in the preparation of Co-CFA-1.

[0017] Preferably, the vacuum drying process in the preparation of Co-CFA-1 is carried out at 220–250°C.

[0018] Preferably, the molar ratio of aluminum in the co-catalyst to cobalt in Co-CFA-1 is 100-300:1, more preferably 150-160:1.

[0019] Preferably, the molar ratio of alkylaluminum to methylaluminoxane in the co-catalyst is 4:1.

[0020] Preferably, the alkyl aluminum is diethylaluminum chloride.

[0021] In the most preferred embodiment of the butadiene polymerization catalyst of the present invention, the molar ratio of aluminum in the co-catalyst to cobalt in Co-CFA-1 is 150-160:1; the co-catalyst is composed of diethylaluminum chloride and methylaluminoxane, and the molar ratio of diethylaluminum chloride to methylaluminoxane is 4:1.

[0022] CFA-1 in this invention is a rigid metal-organic framework material, which can be prepared by methods reported in the literature. Specifically, this invention recommends the following preparation method:

[0023] After adding DMF and acetic acid to a polyvinyl fluoride lining and mixing, the mixture is stirred at room temperature for 10-20 min. Zn·2H2O and H2bibta (1H,1'H-5,5'-bibenzo[d][1,2,3]triazole) are then added and ultrasonically mixed. The mixture is then placed in an oven and reacted at 90℃ for 16 h, followed by a reaction at 120℃ for 18-24 h. The mixture is washed with DMF and isopropanol and vacuum dried at 50-90℃ to obtain CFA-1. The volume ratio of DMF to acetic acid is 22-28:0.8-1.2, preferably 24-26:0.8-1; the mass-to-volume ratio of Zn·2H2O to H2bibta is 3-3.6:0.8-1.2, preferably 3.3-3.6:0.8-1.

[0024] The present invention does not have special requirements for the amount of solvent in the butadiene polymerization catalyst, as long as it can disperse Co-CFA-1 and the co-catalyst. In a specific embodiment of the present invention, the mass concentration of Co-CFA-1 in the catalyst is 4-6 g / L.

[0025] In a second aspect, the present invention provides a method for preparing the Co-CFA-1-based butadiene polymerization catalyst described in the first aspect, the method comprising:

[0026] (1) The NMF solution of CFA-1 and cobalt acetate tetrahydrate was heated at 55-65°C for 18-24 hours, and then filtered, washed and vacuum dried to obtain Co-CFA-1;

[0027] (2) Add Co-CFA-1 to a clean, dry reaction vessel, first add a toluene solution of alkyl aluminum, then add a toluene solution of methylaluminoxane, and activate at 20-40°C for 10-40 min to obtain a butadiene polymerization catalyst based on Co-CFA-1.

[0028] Preferably, in step (1), the mass ratio of CFA-1 to cobalt acetate tetrahydrate is 0.06-0.12:1.2-1.8, more preferably 0.07-0.10:1.3-1.7.

[0029] Preferably, in step (1), the mass-to-volume ratio of CFA-1 to NMF is 1:350 to 420.

[0030] Preferably, in step (1), methanol is used as the washing agent.

[0031] Preferably, in step (1), the vacuum drying is carried out at 220–250°C.

[0032] To further improve the catalyst preparation efficiency, step (2) of this invention can usually be carried out under inert gas protection or vacuum conditions. This invention does not strictly limit the inert gas used; for example, more economical nitrogen (N2) can be selected. Preferably, step (2) is carried out under vacuum conditions, with activation conditions of 20-25°C for 20-30 minutes.

[0033] Thirdly, the present invention provides the application of the Co-CFA-1-based butadiene polymerization catalyst described in the first aspect in the preparation of cis-polybutadiene.

[0034] The specific application involves mixing 1,3-butadiene monomer and a Co-CFA-1-based butadiene polymerization catalyst in a solvent, followed by a polymerization reaction to generate cis-polybutadiene. The reaction is carried out under vacuum conditions.

[0035] As a further preferred option, the solvent is toluene.

[0036] As a further preferred option, the butadiene polymerization process is carried out under the protection of an inert gas to further enhance the activity of butadiene polymerization. This invention does not strictly limit the inert gas used; for example, more economical nitrogen (N2) can be selected.

[0037] As a further preferred option, the amount of the Co-CFA-1-based butadiene polymerization catalyst is controlled such that the molar ratio of cobalt to 1,3-butadiene monomer is 5.0 × 10⁻⁶. -4 ~2.5×10 -3 .

[0038] As a further preferred option, the concentration of 1,3-butadiene in the polymerization reaction system is 1.5-3.5M.

[0039] As a further preferred option, the polymerization reaction temperature is 20-50℃. Under the polymerization conditions of this invention, the reaction rate is uniform, a high cis structure can be achieved, and polymerization is generally completed within 80-150 minutes. The molecular weight is 2.6 × 10⁻⁶. 4 ~8.7×10 5 Furthermore, the polymerization reaction temperature is further optimized to be 21℃ and the reaction time to be 2.5h.

[0040] Compared with the prior art, the present invention has the following beneficial effects:

[0041] The butadiene polymerization catalyst based on Co-CFA-1 provided by this invention has advantages such as wear resistance, high tensile strength, and high activity. It can prepare high-quality polybutadiene rubber products with high cis structure content, controllable molecular weight, and narrow molecular weight distribution, and the product has a high yield. Attached Figure Description

[0042] Figure 1 This is a SEM image of Co-CFA-1 prepared in Example 1. Detailed Implementation

[0043] The present invention will be illustrated below with specific examples. It should be noted that the embodiments are only for further illustration of the present invention and should not be construed as limiting the scope of protection of the present invention, which is not limited thereto in any way. Those skilled in the art can make some non-essential improvements and adjustments based on the above-described invention.

[0044] Unless otherwise specified in the embodiments of this invention, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be obtained through conventional technical means or commercially available.

[0045] Example 1

[0046] 1. Preparation of catalysts

[0047] (1) Preparation of CFA-1

[0048] Measure 100 mL of DMF using a graduated cylinder and pour it into a polyvinyl fluoride liner. Add 4 mL of acetic acid using a pipette, mix, and stir at room temperature for 10 min. Then weigh 0.74 g of (CH3COO)2Zn·2H2O and 0.2 g of H2bibta into the above solution, mix thoroughly by ultrasonication, place the mixed solution in a 250 mL reaction vessel, seal it, and place it in an oven to react at 90 °C for 16 h and then at 120 °C for 24 h. After the sample cools to room temperature, filter it and wash it three times each with DMF and isopropanol. Finally, dry it in a vacuum oven at 50 °C for 24 h to obtain 0.3 g (0.24 mmol) of white CFA-1.

[0049] (2) Preparation of Co-CFA-1:

[0050] 1.64 g of cobalt(II) acetate tetrahydrate was weighed into a 100 mL beaker. 40 mL of N-methylformamide (NMF) was measured into the beaker using a graduated cylinder and dissolved by sonication. Then, 0.1 g of CFA-1 was weighed into the above solution and dissolved by sonication. The reaction was carried out at 60 °C for 24 hours. After the reaction was complete, the purple precipitate was filtered off and washed with hot NMF until the filtrate was completely colorless. Then, it was washed with methanol and dried under vacuum at 250 °C for 24 hours to obtain Co-CFA-1. The SEM image of this product is shown below. Figure 1 The mass percentage content of Co in the EDS was calculated to be 13.88%, as detailed in Table 1.

[0051] Table 1

[0052] element Wt% C 65.14 N 3.42 O 15.94 Co 13.88 Zn 1.63 Total: 100.00

[0053] (3) After cleaning and baking at high temperature to remove moisture, add 6.2 mg Co-CFA-1 to the three-necked reaction flask, purge with nitrogen three times, and then evacuate. First, add 0.9 mL (2 mol / L) of toluene solution of diethylaluminum chloride, followed by 0.3 mL (1.5 mol / L) of toluene solution of methylaluminoxane for activation. Activate at 25 °C for 20 min to obtain a butadiene polymerization catalyst based on Co-CFA-1, wherein the molar ratio of aluminum element in the co-catalyst to cobalt element in Co-CFA-1 is 154:1.

[0054] 2. Synthetic polydiene rubber

[0055] A toluene solution (7.26 mL, 23.33 mmol 1,3-butadiene) of toluene and 1,3-butadiene was injected into a three-necked flask containing a Co-CFA-1-based butadiene polymerization catalyst. The molar ratio of cobalt to 1,3-butadiene was 6.2 × 10⁻⁶. -4 The mixture was stirred at 21°C for 2.5 hours. After the reaction was complete, the mixture was quenched for 5 minutes with a 2,6-tert-butyl / ethanol solution (3 mL) at a volume ratio of 1:100. The precipitate was washed with ethanol (30 mL), and the solid was vacuum dried at 55°C for 12 hours to obtain polybutadiene rubber.

[0056] The yield of polybutadiene rubber was determined by gravimetric analysis. The yield was 91.2%, with stereoselectivity of 99.6% 1,4-cis, 0.22% 1,4-trans, and 0.18% 1,2-vinyl, and Mn was 8.2 × 10⁻⁶. 5 The Mw / Mn ratio is 2.6.

[0057] Example 2 (different from Example 1 in terms of the amount of co-catalyst used)

[0058] 1. Preparation of rare earth catalysts

[0059] (1) Preparation of CFA-1: Same as in Example 1

[0060] (2) Preparation of Co-CFA-1:

[0061] 1.64 g of cobalt(II) acetate tetrahydrate was weighed into a 100 mL beaker. 40 mL of N-methylformamide (NMF) solution was measured into the beaker using a graduated cylinder and dissolved by sonication. Then, 0.1 g of CFA-1 was weighed into the above solution and dissolved by sonication. The reaction was carried out at 60 °C for 24 hours. After the reaction was complete, the purple precipitate was filtered out and washed with hot NMF until the filtrate was completely colorless. Then, it was washed with methanol and dried under vacuum at 250 °C for 24 hours to obtain Co-CFA-1. The mass percentage of Co in Co-CFA-1 was calculated to be 13.88% using EDS content analysis.

[0062] (3) After cleaning and baking at high temperature to remove moisture, add 6.2 mg Co-CFA-1 to the three-necked reaction flask, purge with nitrogen three times, and then evacuate. First, add 1.5 mL (2 mol / L) of toluene solution of diethylaluminum chloride, followed by 0.5 mL (1.5 mol / L) of toluene solution of methylaluminoxane for activation. Activate at 25 °C for 20 min to obtain a butadiene polymerization catalyst based on Co-CFA-1, wherein the molar ratio of aluminum element in the co-catalyst to cobalt element in Co-CFA-1 is 257:1.

[0063] 2. Synthetic polydiene rubber

[0064] A toluene solution (7.26 mL, 23.33 mmol 1,3-butadiene) of toluene and 1,3-butadiene was injected into a three-necked flask containing a Co-CFA-1-based butadiene polymerization catalyst. The molar ratio of cobalt to 1,3-butadiene was 6.2 × 10⁻⁶. -4 The mixture was stirred at 21°C for 2.5 hours. After the reaction was complete, the mixture was quenched for 5 minutes with a 2,6-tert-butyl / ethanol solution (3 mL) at a volume ratio of 1:100. The precipitate was washed with ethanol (30 mL) and the solid was vacuum dried at 55°C for 12 hours to obtain polybutadiene rubber.

[0065] The yield of polybutadiene rubber was determined by gravimetric analysis to be 89.8%, with stereoselectivity of 99.1% 1,4-cis, 0.58% 1,4-trans, and 0.32% 1,2-vinyl, and Mn of 5.5 × 10⁻⁶. 5 The Mw / Mn ratio is 2.65.

[0066] Example 3 (different from the co-catalyst mixing ratio used in Example 1)

[0067] 1. Preparation of rare earth catalysts

[0068] (1) Preparation of CFA-1: Same as in Example 1

[0069] (2) Preparation of Co-CFA-1:

[0070] 1.64 g of cobalt(II) acetate tetrahydrate was weighed into a 100 mL beaker. 40 mL of N-methylformamide (NMF) solution was measured into the beaker using a graduated cylinder and dissolved by sonication. Then, 0.1 g of CFA-1 was weighed into the above solution and dissolved by sonication. The reaction was carried out at 60 °C for 24 hours. After the reaction was complete, the purple precipitate was filtered out and washed with hot NMF until the filtrate was completely colorless. Then, it was washed with methanol and dried under vacuum at 250 °C for 24 hours to obtain Co-CFA-1. The mass percentage of Co in Co-CFA-1 was calculated to be 13.88% using EDS content analysis.

[0071] (3) After cleaning and baking at high temperature to remove moisture, add 6.2 mg Co-CFA-1 to the three-necked reaction flask, purge with nitrogen three times, and then evacuate. First, add 0.6 mL (2 mol / L) of toluene solution of diethylaluminum chloride, followed by 0.2 mL (1.5 mol / L) of toluene solution of methylaluminoxane for activation. Activate at 25 °C for 20 min to obtain a butadiene polymerization catalyst based on Co-CFA-1, wherein the molar ratio of aluminum element in the co-catalyst to cobalt element in Co-CFA-1 is 103:1.

[0072] 2. Synthetic polydiene rubber

[0073] A toluene solution (7.26 mL, 23.33 mmol 1,3-butadiene) of toluene and 1,3-butadiene was injected into a three-necked flask containing a Co-CFA-1-based butadiene polymerization catalyst. The molar ratio of cobalt to 1,3-butadiene was 6.2 × 10⁻⁶. -4 The mixture was stirred at 21°C for 2.5 hours. After the reaction was complete, the mixture was quenched for 5 minutes with a 2,6-tert-butyl / ethanol solution (3 mL) at a volume ratio of 1:100. The precipitate was washed with ethanol (30 mL) and the solid was vacuum dried at 55°C for 12 hours to obtain polybutadiene rubber.

[0074] The yield of polybutadiene rubber was determined by gravimetric analysis to be 86.8%, with stereoselectivity of 94.9% 1,4-cis, 3.89% 1,4-trans, and 1.21% 1,2-vinyl, and Mn of 9.6 × 10⁻⁶. 4 Mw / Mn is 3.3.

[0075] Example 4 (The activation time is different from that used in Example 1)

[0076] 1. Preparation of rare earth catalysts

[0077] (1) Preparation of CFA-1: Same as in Example 1

[0078] (2) Preparation of Co-CFA-1:

[0079] 1.64 g of cobalt(II) acetate tetrahydrate was weighed into a 100 mL beaker. 40 mL of N-methylformamide (NMF) solution was measured into the beaker using a graduated cylinder and dissolved by sonication. Then, 0.1 g of CFA-1 was weighed into the above solution and dissolved by sonication. The reaction was carried out at 60 °C for 24 hours. After the reaction was complete, the purple precipitate was filtered out and washed with hot NMF until the filtrate was completely colorless. Then, it was washed with methanol and dried under vacuum at 250 °C for 24 hours to obtain Co-CFA-1. The mass percentage of Co in Co-CFA-1 was calculated to be 13.88% using EDS content analysis.

[0080] (3) After cleaning and baking at high temperature to remove moisture, add 6.2 mg Co-CFA-1 to the three-necked reaction flask, purge with nitrogen three times, and then evacuate. First, add 0.9 mL (2 mol / L) of diethylaluminum chloride in toluene solution, followed by 0.3 mL (1.5 mol / L) of methylaluminoxane in toluene solution for activation. Activate at 25 °C for 40 min to obtain a butadiene polymerization catalyst based on Co-CFA-1, wherein the molar ratio of aluminum element in the co-catalyst to cobalt element in Co-CFA-1 is 154:1.

[0081] 2. Synthetic polydiene rubber

[0082] A toluene solution (7.26 mL, 23.33 mmol 1,3-butadiene) of toluene and 1,3-butadiene was injected into a three-necked flask containing a Co-CFA-1-based butadiene polymerization catalyst. The molar ratio of cobalt to 1,3-butadiene was 6.2 × 10⁻⁶. -4 The mixture was stirred at 21°C for 2.5 hours. After the reaction was complete, the mixture was quenched for 5 minutes with a 2,6-tert-butyl / ethanol solution (3 mL) at a volume ratio of 1:100. The precipitate was washed with ethanol (30 mL) and the solid was vacuum dried at 55°C for 12 hours to obtain polybutadiene rubber.

[0083] The yield of polybutadiene rubber was determined by gravimetric analysis. The yield was 91.4%, with stereoselectivity of 97.9% 1,4-cis, 1.28% 1,4-trans, and 0.82% 1,2-vinyl, and Mn of 1.8 × 10⁻⁶. 5 The Mw / Mn ratio is 2.82.

[0084] Example 5 (different type of cocatalyst used in Example 1)

[0085] 1. Preparation of rare earth catalysts

[0086] (1) Preparation of CFA-1: Same as in Example 1

[0087] (2) Preparation of Co-CFA-1:

[0088] 1.64 g of cobalt(II) acetate tetrahydrate was weighed into a 100 mL beaker. 40 mL of N-methylformamide (NMF) solution was measured into the beaker using a graduated cylinder and dissolved by sonication. Then, 0.1 g of CFA-1 was weighed into the above solution and dissolved by sonication. The reaction was carried out at 60 °C for 24 hours. After the reaction was complete, the purple precipitate was filtered out and washed with hot NMF until the filtrate was completely colorless. Then, it was washed with methanol and dried under vacuum at 250 °C for 24 hours to obtain Co-CFA-1. The mass percentage of Co in Co-CFA-1 was calculated to be 13.88% using EDS content analysis.

[0089] (3) After cleaning and baking at high temperature to remove moisture, add 6.2 mg Co-CFA-1 to the three-necked reaction flask, purge with nitrogen three times, evacuate, add 1.5 mL of toluene solution of methylaluminoxane (1.5 mol / L) for activation, activate at 25 °C for 20 min to obtain butadiene polymerization catalyst based on Co-CFA-1, wherein the molar ratio of aluminum element in the co-catalyst to cobalt element in Co-CFA-1 is 154:1.

[0090] 2. Synthetic polydiene rubber

[0091] A toluene solution (7.26 mL, 23.33 mmol 1,3-butadiene) of toluene and 1,3-butadiene was injected into a three-necked flask containing a Co-CFA-1-based butadiene polymerization catalyst. The molar ratio of cobalt to 1,3-butadiene was 6.2 × 10⁻⁶. -4 The mixture was stirred at 21°C for 2.5 hours. After the reaction was complete, the mixture was quenched for 5 minutes with a 2,6-tert-butyl / ethanol solution (3 mL) at a volume ratio of 1:100. The precipitate was washed with ethanol (30 mL) and the solid was vacuum dried at 55°C for 12 hours to obtain polybutadiene rubber.

[0092] The yield of polybutadiene rubber was determined by gravimetric analysis. The yield was 58.8%, with stereoselectivity of 85.6% 1,4-cis, 8.1% 1,4-trans, and 6.3% 1,2-vinyl, and Mn was 1.2 × 10⁻⁶. 4 The Mw / Mn ratio is 4.2.

[0093] Example 6 (different type of cocatalyst used in Example 1)

[0094] 1. Preparation of rare earth catalysts

[0095] (1) Preparation of CFA-1: Same as in Example 1

[0096] (2) Preparation of Co-CFA-1:

[0097] 1.64 g of cobalt(II) acetate tetrahydrate was weighed into a 100 mL beaker. 40 mL of N-methylformamide (NMF) solution was measured into the beaker using a graduated cylinder and dissolved by sonication. Then, 0.1 g of CFA-1 was weighed into the above solution and dissolved by sonication. The reaction was carried out at 60 °C for 24 hours. After the reaction was complete, the purple precipitate was filtered out and washed with hot NMF until the filtrate was completely colorless. Then, it was washed with methanol and dried under vacuum at 250 °C for 24 hours to obtain Co-CFA-1. The mass percentage of Co in Co-CFA-1 was calculated to be 13.88% using EDS content analysis.

[0098] (3) After cleaning and baking at high temperature to remove moisture, add 6.2 mg Co-CFA-1 to the three-necked reaction flask, purge with nitrogen three times, and then evacuate. First, add 0.7 mL (1.5 mol / L) of triisobutylaluminum in toluene solution, and then add 0.6 mL of diethylaluminum chloride (2 mol / L) in toluene solution for activation. Activate at 25 °C for 20 min to obtain a butadiene polymerization catalyst based on Co-CFA-1, wherein the molar ratio of aluminum element in the co-catalyst to cobalt element in Co-CFA-1 is 154:1.

[0099] 2. Synthetic polydiene rubber

[0100] A toluene solution (7.26 mL, 23.33 mmol 1,3-butadiene) of toluene and 1,3-butadiene was injected into a three-necked flask containing a Co-CFA-1-based butadiene polymerization catalyst. The molar ratio of cobalt to 1,3-butadiene was 6.2 × 10⁻⁶. -4 The mixture was stirred at 21°C for 2.5 hours. After the reaction was complete, the mixture was quenched for 5 minutes with a 2,6-tert-butyl / ethanol solution (3 mL) at a volume ratio of 1:100. The precipitate was washed with ethanol (30 mL) and the solid was vacuum dried at 55°C for 12 hours to obtain polybutadiene rubber.

[0101] The yield of polybutadiene rubber was determined by gravimetric analysis. The yield was 90.1%, with stereoselectivity of 91.56% 1,4-cis, 4.82% 1,4-trans, and 3.62% 1,2-vinyl, and Mn of 8.8 × 10⁻⁶. 4 Mw / Mn is 3.2.

[0102] Example 7 (different type of cocatalyst used in Example 1)

[0103] 1. Preparation of rare earth catalysts

[0104] (1) Preparation of CFA-1: Same as in Example 1

[0105] (2) Preparation of Co-CFA-1:

[0106] 1.64 g of cobalt(II) acetate tetrahydrate was weighed into a 100 mL beaker. 40 mL of N-methylformamide (NMF) solution was measured into the beaker using a graduated cylinder and dissolved by sonication. Then, 0.1 g of CFA-1 was weighed into the above solution and dissolved by sonication. The reaction was carried out at 60 °C for 24 hours. After the reaction was complete, the purple precipitate was filtered out and washed with hot NMF until the filtrate was completely colorless. Then, it was washed with methanol and dried under vacuum at 250 °C for 24 hours to obtain Co-CFA-1. The mass percentage of Co in Co-CFA-1 was calculated to be 13.88% using EDS content analysis.

[0107] (3) After cleaning and baking at high temperature to remove moisture, add 6.2 mg Co-CFA-1 to the three-necked reaction flask, purge with nitrogen three times, and then evacuate. First, add 1.2 mL (1.5 mol / L) of triisobutylaluminum in toluene solution, and then add 0.3 mL (1.5 mol / L) of methylaluminoxane in toluene solution for activation. Activate at 25 °C for 20 min to obtain a butadiene polymerization catalyst based on Co-CFA-1, wherein the molar ratio of aluminum element in the co-catalyst to cobalt element in Co-CFA-1 is 154:1.

[0108] 2. Synthetic polydiene rubber

[0109] A toluene solution (7.26 mL, 23.33 mmol 1,3-butadiene) of toluene and 1,3-butadiene was injected into a three-necked flask containing a Co-CFA-1-based butadiene polymerization catalyst. The molar ratio of cobalt to 1,3-butadiene was 6.2 × 10⁻⁶. -4 The mixture was stirred at 21°C for 2.5 hours. After the reaction was complete, the mixture was quenched for 5 minutes with a 2,6-tert-butyl / ethanol solution (3 mL) at a volume ratio of 1:100. The precipitate was washed with ethanol (30 mL) and the solid was vacuum dried at 55°C for 12 hours to obtain polybutadiene rubber.

[0110] The yield of polybutadiene rubber was determined by gravimetric analysis to be 85.4%, with stereoselectivity of 92.7% 1,4-cis, 4.31% 1,4-trans, and 2.99% 1,2-vinyl, and Mn of 6.7 × 10⁻⁶. 4 The Mw / Mn ratio is 3.6.

[0111] Example 8 (different type of cocatalyst used in Example 1)

[0112] 1. Preparation of rare earth catalysts

[0113] (1) Preparation of CFA-1: Same as in Example 1

[0114] (2) Preparation of Co-CFA-1:

[0115] 1.64 g of cobalt(II) acetate tetrahydrate was weighed into a 100 mL beaker. 40 mL of N-methylformamide (NMF) solution was measured into the beaker using a graduated cylinder and dissolved by sonication. Then, 0.1 g of CFA-1 was weighed into the above solution and dissolved by sonication. The reaction was carried out at 60 °C for 24 hours. After the reaction was complete, the purple precipitate was filtered out and washed with hot NMF until the filtrate was completely colorless. Then, it was washed with methanol and dried under vacuum at 250 °C for 24 hours to obtain Co-CFA-1. The mass percentage of Co in Co-CFA-1 was calculated to be 13.88% using EDS content analysis.

[0116] (3) After cleaning and baking at high temperature to remove moisture, add 6.2 mg Co-CFA-1 to the three-necked reaction flask, purge with nitrogen three times, and then evacuate. First, add 1.2 mL of dichloroethylaluminum in toluene solution (1.5 mol / L), followed by 0.3 mL of methylaluminoxane in toluene solution for activation. Activate at 25 °C for 20 min to obtain a butadiene polymerization catalyst based on Co-CFA-1, wherein the molar ratio of aluminum in the co-catalyst to cobalt in Co-CFA-1 is 154:1.

[0117] 2. Synthetic polydiene rubber

[0118] A toluene solution (7.26 mL, 23.33 mmol 1,3-butadiene) of toluene and 1,3-butadiene was injected into a three-necked flask containing a Co-CFA-1-based butadiene polymerization catalyst. The molar ratio of cobalt to 1,3-butadiene was 6.2 × 10⁻⁶. -4 The mixture was stirred at 21°C for 2.5 hours. After the reaction was complete, the mixture was quenched for 5 minutes with a 2,6-tert-butyl / ethanol solution (3 mL) at a volume ratio of 1:100. The precipitate was washed with ethanol (30 mL) and the solid was vacuum dried at 55°C for 12 hours to obtain polybutadiene rubber.

[0119] The yield of polybutadiene rubber was determined by gravimetric analysis to be 87.1%, with stereoselectivity of 86.7% 1,4-cis, 8.8% 1,4-trans, and 4.5% 1,2-vinyl, and Mn of 1.2 × 10⁻⁶. 4 The Mw / Mn ratio is 3.8.

Claims

1. A catalyst for the preparation of cis-polybutadiene based on Co-CFA-1 for the polymerization of butadiene, characterized by: The catalyst for preparing cis-polybutadiene by butadiene polymerization based on Co-CFA-1 includes Co-CFA-1, a co-catalyst, and toluene solvent, wherein the molar ratio of aluminum in the co-catalyst to cobalt in Co-CFA-1 is 20~300:

1. Co-CFA-1 was prepared by the following method: a dispersion of CFA-1 and cobalt acetate tetrahydrate NMF was heated at 55-65°C for 18-30 hours, and then filtered, washed and vacuum dried to obtain Co-CFA-1. The co-catalyst is composed of alkylaluminum and methylaluminoxane in a molar ratio of 2 to 5:1, wherein the alkylaluminum is selected from at least one of diethylaluminum chloride, triisobutylaluminum and diethylaluminum chloride.

2. A Co-CFA-1 based catalyst for the polymerization of butadiene to prepare cis-polybutadiene according to claim 1, characterized in that: The mass ratio of CFA-1 to cobalt acetate tetrahydrate is 0.06~0.12:1.2~1.

8.

3. A Co-CFA-1 based catalyst for the polymerization of butadiene to prepare cis-polybutadiene according to claim 2, characterized in that: The mass ratio of CFA-1 to cobalt acetate tetrahydrate is 0.07~0.10:1.3~1.

7.

4. The Co-CFA-1 based catalyst for butadiene polymerization to prepare cis-polybutadiene according to claim 1, characterized by: The molar ratio of aluminum in the co-catalyst to cobalt in Co-CFA-1 is 100~300 :

1.

5. The catalyst for the preparation of cis-polybutadiene based on Co-CFA-1 polymerization of butadiene as described in claim 4, characterized in that: The molar ratio of aluminum in the co-catalyst to cobalt in Co-CFA-1 is 150-160:

1.

6. The catalyst for the preparation of cis-polybutadiene based on Co-CFA-1 polymerization of butadiene as described in claim 1, characterized in that: In the co-catalyst, the molar ratio of alkylaluminum to methylaluminoxane is 4:

1.

7. The catalyst for the preparation of cis-polybutadiene based on Co-CFA-1 polymerization of butadiene as described in claim 1, characterized in that: In the catalyst for the polymerization of butadiene to prepare cis-polybutadiene, the molar ratio of aluminum in the co-catalyst to cobalt in Co-CFA-1 is 150~160:1; the co-catalyst is composed of diethylaluminum chloride and methylaluminoxane, and the molar ratio of diethylaluminum chloride to methylaluminoxane is 4:

1.

8. A method for preparing a catalyst for the polymerization of butadiene based on Co-CFA-1 to prepare cis-polybutadiene as described in any one of claims 1-7, characterized in that: The preparation method includes: (1) The NMF solution of CFA-1 and cobalt acetate tetrahydrate was heated at 55~65°C for 18~24 hours, and then filtered, washed and vacuum dried to obtain Co-CFA-1; (2) Add Co-CFA-1 to a clean, dry reaction vessel, first add a toluene solution of alkyl aluminum, then add a toluene solution of methylaluminoxane, and activate at 20~40℃ for 10~40 min to obtain a catalyst for the preparation of cis-polybutadiene by butadiene polymerization based on Co-CFA-1.

9. The preparation method according to claim 8, characterized in that: Step (2) is carried out under vacuum conditions, with activation conditions of 20~25℃ for 20~30 min.

10. The application of the Co-CFA-1-based catalyst for the polymerization of butadiene to prepare cis-polybutadiene as described in any one of claims 1-7 in the preparation of cis-polybutadiene.

11. The application as described in claim 10, characterized in that: The specific application involves mixing 1,3-butadiene monomer and a Co-CFA-1-based butadiene polymerization catalyst to prepare cis-polybutadiene in a solvent, followed by polymerization to generate cis-polybutadiene. The reaction is carried out under vacuum conditions.

12. The application as described in claim 11, characterized in that: The solvent is toluene.

Images