Metallocene catalyst system, polyisobutylene and process for the preparation thereof

Abstract

The application discloses a kind of metallocene catalyst system, polyisobutylene and preparation method thereof.The metallocene catalyst system includes A, B, C, D four components;Component A is metallocene complex;Component B is borate;Component C is alkyl aluminum;Component D is selected from alkyl ether of carbon atom number 2~8.The metallocene catalyst system used in the application has high catalytic activity and raw materials are cheap and easy to obtain, which can greatly reduce production cost.Compared with BF3 catalyst system, the catalyst system provided by the application is non-toxic, harmless, non-polluting, non-corrosive, which can effectively solve the technical problems of toxic, harmful, corrosion and pollution existing in traditional technical route, thereby improving the operating environment, and ensuring personal health.The application can synthesize narrow distribution, medium molecular weight polyisobutylene under mild conditions of 0~80 DEG C, i.e., using conventional cooling water to remove heat, which solves the low temperature reaction problem existing in traditional cationic polymerization.

Description

Technical Field

[0001] This invention relates to a metallocene catalyst system, polyisobutylene, and a method for preparing the same. Background Technology

[0002] With the widespread promotion of ethanol gasoline in China and the ban on MTBE as a gasoline additive, many MTBE production units have switched to producing isobutylene, resulting in a serious surplus of isobutylene resources. How to make high-quality use of isobutylene resources and transform them into high-value-added products is a major challenge facing the transformation and upgrading of China's refining and chemical industry.

[0003] Medium molecular weight polyisobutylene (MBPB) typically has an index-average molecular weight (Mn) of 10,000–50,000. It possesses excellent airtightness, aging resistance, and corrosion resistance, and exhibits good compatibility with most polymers. It is widely used in adhesives, sealing materials, vibration-damping materials, pressure-sensitive adhesives, grease tackifiers, gap-filling materials, and chewing gum bases. In particular, with the rapid growth in demand for insulated glass, chewing gum bases, and adhesives, the market for MBPB is showing a positive development trend. Producing MBPB from isobutylene is an effective way to utilize isobutylene resources in a high-quality manner.

[0004] Metallocenes possess a single active center, which enables the resulting olefin polymers to exhibit good homogeneity during catalytic polymerization, thus resulting in polymer products with a narrow distribution. Furthermore, metallocene catalysts possess flexible and tunable structures, allowing for the improvement of catalytic performance through the regulation of their steric and electronic effects.

[0005] Therefore, metallocene-catalyzed isobutylene polymerization is commonly used to produce polyisobutylene materials. Summary of the Invention

[0006] To improve the methods for producing polyisobutylene, this invention provides a novel metallocene catalyst system that can catalyze the polymerization of isobutylene under mild conditions to produce a narrowly distributed, medium-molecular-weight polyisobutylene.

[0007] As one aspect of the present invention, a metallocene catalyst system is disclosed, the catalyst system comprising four components A, B, C, and D; component A is a metallocene complex; component B is a borate; component C is an alkylaluminum; and component D is selected from dialkyl ethers having 2 to 8 carbon atoms.

[0008] In any specific embodiment, component A is a bridged or non-bridged metallocene complex; the general structural formula (I) of the bridged component A is Cp' n (X')MX m The structural formula (II) of the non-bridging component A is Cp' nMX m ;

[0009] In formulas (Ⅰ) and (Ⅱ), Cp' is selected from substituted or unsubstituted cyclopentadienyl, indenyl, or fluorenyl; M is the active center metal; X is selected from one of halogen, alkyl, alkoxy, amino, or acid radical; n is 1 or 2, and m is an integer satisfying the valence state of M.

[0010] In any specific embodiment, the substituent in Cp' is selected from one or more of aryloxy, substituted aryloxy, alkyl, alkoxy, and silyl groups.

[0011] In any specific embodiment, the substituted aryloxy group is selected from aryloxy groups substituted by alkyl groups having 1 to 18 carbon atoms.

[0012] In any specific embodiment, M is selected from Ti, Zr, or Hf.

[0013] In any specific embodiment, when component A is a bridged metallocene complex, X' is selected from one of SiR2, CR2, SiR2SiR2, CR2CR2, CR=CR or (CR3)2Si.

[0014] In any specific embodiment, R is hydrogen; or R is selected from alkyl, aryl, silyl, haloalkyl or haloaryl groups having less than 20 carbon atoms.

[0015] In any specific embodiment, component A is selected from one of Cp'TiX2, Cp'ZrX2, Cp'2ZrX2, Cp'2HfX2, and Cp'2(CR3)2SiZrX2.

[0016] In any specific embodiment, component B is selected from Ph3CB(C6F5)4, PhNMe2HB(C6F5)4, B(C6F5)3 or [(C a H 2a+1 )2NH(C b H2 b+1 One of the formulas is [B(C6F5)4], where 2≤a≤20, 1≤b≤20, and a and b are both integers.

[0017] Furthermore, component B is selected from Ph3CB(C6F5)4, PhNMe2HB(C6F5)4, or B(C6F5)3.

[0018] In any specific embodiment, component C is trialkylaluminum; the trialkylaluminum is selected from one of trimethylaluminum, triethylaluminum, triisopropylaluminum, triisobutylaluminum, tri-n-hexylaluminum, tri-n-octylaluminum, tri-n-decylaluminum and tri-n-dodecylaluminum.

[0019] Furthermore, component C is selected from one of triethylaluminum, triisopropylaluminum, triisobutylaluminum, tri-n-hexylaluminum, or tri-n-octylaluminum.

[0020] In any specific embodiment, component D is selected from one of methyl ether, isopropyl ether, n-butyl ether, or methyl tert-butyl ether.

[0021] As another aspect of the present invention, the application of the above-described metallocene catalyst system in the catalytic polymerization of isobutylene is involved.

[0022] As another aspect of the present invention, a method for preparing polyisobutylene is provided, wherein the above-mentioned metallocene catalyst system is used to catalyze the polymerization of isobutylene during the preparation of polyisobutylene.

[0023] Specifically, it includes the following steps:

[0024] S1. Refining of raw materials and solvents

[0025] After sieving isobutylene and solvent, the mixture is then dried and dehydrated.

[0026] S2, Aggregation

[0027] Under dry, oxygen-free conditions, solvent, isobutylene, and component C are added sequentially, stirred, and the temperature is raised. Then, components A, B, and D are added to participate in the polymerization, yielding the crude polymer product; S3, Crude Product Pretreatment

[0028] The crude polymer obtained by acid washing in S2 is then subjected to alkali washing and water washing in sequence until the water washing solution is neutral. After standing and separating into layers, the upper oil phase is taken.

[0029] S4. Purification of polymerization products

[0030] The oil phase product was distilled under reduced pressure to obtain polyisobutylene.

[0031] In any specific embodiment, in S1, the solvent is selected from one or more of C2-C12 straight-chain alkanes, C4-C12 isoalkanes, C3-C8 cycloalkanes, benzene, or substituted benzene.

[0032] In any specific embodiment, in step S2, the polymerization temperature is 0–100°C, the time is 0.1–4 h, and the pressure is 0–2 MPa.

[0033] In any specific embodiment, in S2, the molar ratio of component A to component B is 1:(0.5-3); the molar ratio of component A to component C is 1:(1-60); and the molar ratio of component A to component D is 1:(0.01-1).

[0034] Further, the molar ratio of component A to component B is 1:(1-2.5); the molar ratio of component A to component C is 1:(2-40); and the molar ratio of component A to component D is 1:(0.05-1).

[0035] In any specific embodiment, in S2, the mass ratio of isobutylene to solvent is (2-12):1.

[0036] In any specific embodiment, in S2, the molar ratio of isobutylene to component A is (1 × 10⁻⁶). 4 ~1×10 7 ): 1.

[0037] Further, the molar ratio of isobutylene to component A is (1 × 10⁻⁶). 5 ~1×10 7 ): 1.

[0038] In any specific embodiment, in step S4, the pressure conditions for vacuum distillation are -0.1 to -0.5 MPa, and the temperature is 150 to 200°C.

[0039] As another aspect of the present invention, there is a polyisobutylene prepared by the above method.

[0040] In any specific embodiment, the polyisobutylene has a number-average molecular weight of 5,000 to 100,000 and a molecular weight distribution of 1 to 2.5.

[0041] Furthermore, the polyisobutylene has a number-average molecular weight of 10,000 to 70,000 and a molecular weight distribution of 1 to 2.2.

[0042] The metallocene catalyst system used in this invention has high catalytic activity and uses inexpensive and readily available raw materials, which can significantly reduce production costs. Compared with the BF3 catalyst system, the catalyst system provided by this invention is non-toxic, harmless, non-polluting, and non-corrosive, effectively solving the technical problems of toxicity, corrosion, and pollution associated with traditional technical routes, thereby improving the operating environment and ensuring human health.

[0043] This invention can synthesize polyisobutylene with a narrow distribution and medium molecular weight under mild conditions of 0 to 80°C, i.e., by using conventional cooling water for heat removal, thus solving the problem of low-temperature reaction in traditional cationic polymerization.

[0044] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention are realized and obtained in accordance with the structures particularly pointed out in the description, claims and drawings. Attached Figure Description

[0045] Figure 1 The above is the 1H NMR spectrum of the polyisobutylene product prepared in Example 1 of this invention;

[0046] Figure 2 This is a gel chromatogram of the polyisobutylene product prepared in Example 1 of the present invention;

[0047] Figure 3 The following are gel chromatograms of the polyisobutylene products prepared in Examples 2 to 8 of this invention, arranged in the order of a to g.

[0048] Figure 4 The following are gel chromatograms of the polyisobutylene products prepared in Comparative Examples 1 to 6 of this invention, arranged in the order of h to m. Detailed Implementation

[0049] While exploring methods for synthesizing polyisobutylene, the inventors discovered that current industrial production typically uses Lewis acids such as BF3 and AlCl3 to catalyze the polymerization of isobutylene, requiring the polymerization reaction to be carried out at a low temperature of -40°C via ammonia evaporation for deheating. This process is energy-intensive, produces a highly viscous reaction system, and is prone to clogging and wall adhesion, leading to shorter production cycles. Furthermore, it presents problems such as hydrofluoric acid corrosion of equipment and pollution from fluoride-containing wastewater discharge. Therefore, in recent years, research on polyisobutylene synthesis has primarily focused on the development of metallocene catalyst systems.

[0050] However, metallocene-catalyzed isobutylene polymerization technology still faces the problem of low-temperature reaction, and since metallocene catalysts are not recyclable, catalyst cost has become a key factor restricting its industrial application.

[0051] Andrew G. Carr et al. used the zirconocene catalyst system Cp2ZrMe2 and Cp2Zr(OH)2 / B (C6F5) to catalyze the homopolymerization and copolymerization of isobutylene and isoprene to obtain medium- to high molecular weight polyisobutylene. The reaction temperature was -30 to -78℃, and the number average molecular weight (Mn) of the product was 33,000 to 810,000 (Mw / Mn was 1.5 to 5). However, when the inventors calculated using the data recorded in the literature, they found that the activity of this polymerization reaction decreased significantly with increasing temperature, and the monomer conversion rate was less than 15% at -30℃. (Carr AG, Dawsor DM. Zirconocenes as initiators for carbocationicisobutene home and opolymerizations[J].Macromolecules,1998,31(7):2035-2040.)

[0052] Bochmann et al. used the aluminocenium catalyst system Cp2Al(μ-Me) / B(C6F5)3 to catalyze the polymerization of isobutene to prepare high molecular weight polyisobutene. The reaction temperature was -25 to -78℃, and the number average molecular weight (Mn) of the product was 289,000 to 1,340,000 (Mw / Mn was 1.6 to 3.4). However, the inventors found that the polymerization activity decreased significantly with increasing temperature, and the monomer conversion rate was less than 2% at -25 to -30℃ (Bochmann M, Dawson DM. The aluminocenium cation[Al(C5H5)2]+: a highly effective initiator for the cationic polymerization of isobutene[J]. Angewandte Chemie International Edition in English, 1996, 35(19): 2226-2228.).

[0053] US Patent 5448001 discloses a method for synthesizing medium molecular weight polyisobutylene using isobutylene and / or a mixture of C4 molecules as raw materials, and BF3 / water, alcohol, alkyl-substituted phenol, and acid ether as catalysts at -40 to -20°C, yielding a product with a molecular weight (Mn) of 8000 to 25000. However, the inventors believe that this method requires reaction at low temperatures to suppress chain transfer and obtain a product with a higher molecular weight.

[0054] Irina et al. used a catalytic system composed of AlCl3 and RnAlCl3 / ether to catalyze the polymerization of isobutylene at -20℃ to prepare medium molecular weight polyisobutylene, with product molecular weights ranging from 6800 to 54700. However, the inventors found that the catalytic activity of this catalyst system decreased significantly when preparing products with higher molecular weights; that is, when Mn was 54700, the monomer conversion rate was only 7%. (Vasilenko IV, Nikishev PA, Shiman DI, et al. Cationic polymerization of isobutylene in toluene: towards well-defined exo-olefin terminated medium molecular weight polyisobutylenes under mild conditions[J]. Polymer Chemistry, 2017, 8(8): 1417-1425.)

[0055] In summary, given that existing technologies do not meet the inventor's expectations, the inventor developed this invention through further research and development.

[0056] This invention provides a method for synthesizing medium molecular weight polyisobutylene based on a novel metallocene catalyst system. By providing counterions to the electron donor, the active center of polymerization is restricted, thereby effectively suppressing chain transfer and isomerization side reactions during polymerization. This allows the polymer chain to grow stably at higher temperatures, thus enabling the synthesis of narrowly distributed medium molecular weight polyisobutylene under mild conditions.

[0057] The present invention will be further described below with reference to specific embodiments. The scope of protection of the present invention is not limited by the following embodiments. The main sources of materials involved in the embodiments are shown in Table 1 below. Other materials not specified are all conventional commercially available products.

[0058] Table 1 Material Source Description

[0059]

[0060] The inventors designed a special metallocene catalyst system to catalyze the polymerization of isobutylene, thereby producing medium molecular weight polyisobutylene. The following are specific embodiments of the invention. The evaluation and analytical methods used in the following embodiments of the invention are all as follows:

[0061] (1) The molecular weight and molecular weight distribution of highly active polyisobutylene were determined by Agilent PL220 room temperature gel permeation chromatography. The molecular weight measurement of polyisobutylene products was carried out in accordance with the relevant provisions of "HG / T 4787-2014 Medium Molecular Weight Polyisobutylene"; the molecular weight distribution of products was carried out in accordance with the relevant provisions of "SH / T1759-2007 Determination of Molecular Weight Distribution of Polymers in Solution by Gel Permeation Chromatography".

[0062] (2) The product structure was analyzed by the chemical shift peaks of characteristic H atoms using the proton nuclear magnetic resonance spectrometer. The instrument used was a commercially available 400.13MHz nuclear magnetic resonance spectrometer.

[0063] Example 1

[0064] The metallocene catalyst system provided in this embodiment includes the following components:

[0065] Component A: [2-(2,3,4,5-tetramethylcyclopentadienyl)-4-tert-butyl-6-triphenylmethylphenoxy]titanium dichloride; The synthesis method of component A is referred to Huo Hang. Synthesis, characterization and catalytic properties of metallocene catalysts with restricted geometry [D]. Jilin University, 2015.

[0066] Component B: Ph3CB(C6F5)4;

[0067] Component C: Triisobutylaluminum;

[0068] Component D: Methyl tert-butyl ether;

[0069] In this embodiment, when preparing polyisobutylene, the amount of component A is 10 μmol, and the molar ratios of the other components are: B / A = 2:1, C / A = 50:1, D / A = 1:10. Toluene is used as the solvent, and the amount used is 60 ml. 100 g of isobutylene is also used.

[0070] The preparation method in this embodiment is carried out in a 500ml reaction vessel and specifically includes the following steps:

[0071] S1, will Molecular sieves are loaded into a drying tower, and isobutylene and toluene are continuously passed through the drying tower from bottom to top at a space velocity of 0.5 BV / h under normal temperature and pressure for dehydration.

[0072] S2. Maintain the internal temperature of the reactor at 100℃, introduce high-purity nitrogen to raise the pressure inside the reactor to 0.7 MPa, then purge the air. Repeat this operation 3-5 times. Then, evacuate the reactor to reduce the internal pressure to 0.3 kPa, and immediately introduce high-purity nitrogen to raise the internal pressure to 0.7 MPa. Repeat this operation 3-5 times. After adjusting the internal temperature to 40℃, add the solvent, isobutylene, and component C (triisobutylaluminum) to the reactor. Maintain the temperature and stir for 30 minutes, then add components A, B, and D to start the polymerization reaction. After 1 hour, add 2 ml of ethanol as a terminator and continue stirring for 30 minutes to stop the reaction.

[0073] S3. After the reaction is complete, the unreacted isobutylene monomer is released from the vent tube, the reaction product is released from the bottom of the vessel and collected, the reaction product is washed with 30wt% dilute sulfuric acid, and then the reaction product is further washed with alkali-water or directly with water until neutral. After standing and separating, the upper oil phase is taken to obtain the polyisobutylene intermediate product containing solvent and oligomers.

[0074] S4. The solvent was separated by distillation at atmospheric pressure and 110℃. Then, the by-product oligomers were separated by vacuum distillation at -0.1 to -0.05 MPa and 150 to 200℃. The remaining product was collected to obtain 91.2 g of polyisobutylene product.

[0075] The polyisobutylene product prepared in this embodiment 1 The results of the 1H NMR (hydrogen NMR) and GPC (gel permeation chromatography) analyses are attached. Figure 1 As shown in Figure 2. Through Figure 1 It was observed that the characteristic α-H peaks of polyisobutylene appeared at chemical shifts δ4.64 and δ4.85, and the characteristic β-H peaks of polyisobutylene appeared between chemical shifts δ5 and 5.4. Therefore, the inventors believe that the obtained product is polyisobutylene. Furthermore, through... Figure 2 It can be seen that the product's Mn is 34268 and its molecular weight distribution is 1.87.

[0076] Example 2

[0077] The difference between the preparation method of this embodiment and that of Example 1 is that component A is replaced with dicyclopentadienyl zirconium dichloride, and 88g of product is obtained by distillation.

[0078] The gel permeation chromatography analysis results of the product are attached. Figure 3 As shown in (a), through Figure 3 (a) It can be seen that the product Mn is 19280 and the molecular weight distribution is 1.77.

[0079] Example 3

[0080] The difference between the preparation method of this embodiment and that of Example 1 is that component A is replaced with dimethylsilyl-bridged bisindenylzirconium dichloride, and 92g of product is obtained by distillation.

[0081] The gel permeation chromatography analysis results of the product are attached. Figure 3 As shown in (b), through Figure 3 (b) It can be seen that the product Mn is 16211 and the molecular weight distribution is 1.83.

[0082] Example 4

[0083] The difference between the preparation method of this embodiment and that of Example 1 is that component A is replaced with vinylbistetrahydroindenezirconium dichloride, and 82g of product is obtained by distillation.

[0084] The gel permeation chromatography analysis results of the product are attached. Figure 3 As shown in (c), via Figure 3 (c) It can be seen that the product Mn is 20416 and the molecular weight distribution is 1.79.

[0085] Example 5

[0086] The difference between the preparation method of this embodiment and that of Example 1 is that component A is replaced with dimethylsilyl-bridged bisindenylzirconium dichloride, and 78g of product is obtained by distillation.

[0087] The gel permeation chromatography analysis results of the product are attached. Figure 3 As shown in (d), through Figure 3 (d) It can be seen that the product Mn is 24925 and the molecular weight distribution is 1.73.

[0088] Example 6

[0089] The difference between the preparation method of this embodiment and that of Example 1 is that component A is replaced with isopropylidenecyclopentadienefluorenylzirconium dichloride, and 75g of product is obtained by distillation.

[0090] The gel permeation chromatography analysis results of the product are attached. Figure 3 As shown in (e), through Figure 3(e) It can be seen that the product Mn is 19400 and the molecular weight distribution is 1.75.

[0091] Example 7

[0092] The difference between the preparation method of this embodiment and that of Example 1 is that component A is replaced with bisindenylzirconium dichloride, and 83g of product is obtained by distillation.

[0093] The gel permeation chromatography analysis results of the product are attached. Figure 3 As shown in (f), through Figure 3 (f) It can be seen that the product Mn is 28449 and the molecular weight distribution is 1.71.

[0094] Example 8

[0095] The difference between the preparation method of this embodiment and that of Example 1 is that component A is replaced with bis(isopropylcyclopentadiene) hafnium dichloride, and 89g of product is obtained by distillation.

[0096] The gel permeation chromatography analysis results of the product are attached. Figure 3 As shown in (g), through Figure 3 (g) It can be seen that the product Mn is 21840 and the molecular weight distribution is 2.18.

[0097] The inventors selected a monocerotitanium catalytic system (hereinafter referred to as "monocenetitanium") that is similar to the scheme in this application:

[0098] Catalytic polymerization of isobutylene to produce polyisobutylene is used as Comparative Example 1 of this invention.

[0099] Comparative Example 1

[0100] The monotitanium catalytic system of this comparative example was synthesized according to the relevant methods described in Barsan F, Karam AR, Parent MA, et al. Polymerization of isobutylene and the copolymerization of isobutylene and isoprene initiated by the metallocene derivative Cp*TiMe2(μ-Me)B(C6F5)3[J]. Macromolecules, 1998, 31(24): 8439-8447.

[0101] The preparation method of this comparative example of polyisobutylene is similar to that of Example 1, and specifically includes the following steps: 10 μmol of monotitanium cadmium is used, B / Ti = 2:1, 60 ml of toluene is used as solvent, 100 g of isobutylene is added, and the reaction is carried out at 40 °C for 1 h. After the reaction is completed, the unreacted monomers are separated, the reaction product is released, and the product is washed with acid, alkali and water until neutral to obtain a colorless and transparent intermediate product. The solvent and oligomers are removed by vacuum distillation to finally obtain 41 g of polyisobutylene product.

[0102] The GPC analysis results of the polyisobutylene product prepared in this comparative example are attached. Figure 4 As shown in (h), through Figure 4 (h) shows that the product Mn is 3898 and the molecular weight distribution is 2.1.

[0103] Comparative Example 2

[0104] The difference from Comparative Example 1 is that the solvent was changed from toluene to hexane. The final product yielded 47g of polyisobutylene.

[0105] The GPC analysis results of the polyisobutylene product prepared in this comparative example are attached. Figure 4 As shown in (i), through Figure 4 (i) It can be seen that the product Mn is 1691 and the molecular weight distribution is 3.7.

[0106] Comparative Example 3

[0107] The difference from Comparative Example 1 is that the amount of monocaprophenone was increased to 50 μmol. This resulted in 78 g of polyisobutylene product.

[0108] The GPC analysis results of the polyisobutylene product prepared in this comparative example are attached. Figure 4 As shown in (j), through Figure 4 (j) indicates that the product Mn is 2910 and the molecular weight distribution is 2.33.

[0109] The inventors also selected a rare earth monocronatine scandium catalyst system (hereinafter referred to as "rare earth monocronatine scandium") that is similar to the scheme in this application:

[0110] Catalytic polymerization of isobutylene to produce polyisobutylene is shown as Comparative Example 4 of this invention.

[0111] Comparative Example 4

[0112] The synthesis method of the rare monocronatone scandium catalyst system in this comparative example is based on the relevant method described in Yang Ke, Study on the polymerization reaction of isobutylene initiated by monocronatone scandium [D]. Dalian University of Technology, 2019.

[0113] The comparative method for preparing polyisobutylene includes the following steps: 10 μmol of scandium monocerophenone, B / Ti = 2:1, 60 ml of toluene as solvent, 100 g of isobutylene, reacting at 40 °C for 1 h, separating unreacted monomers after the reaction, releasing the reaction product, and successively washing with acid, alkali, and water until neutral to obtain a colorless and transparent intermediate product, removing the solvent and oligomers by vacuum distillation, and finally obtaining 47 g of polyisobutylene product;

[0114] The GPC analysis results of the polyisobutylene product prepared in this comparative example are attached. Figure 4 As shown in (k), through Figure 4 (k) indicates that the product's Mn is 6765 and its molecular weight distribution is 4.23.

[0115] Comparative Example 5

[0116] The difference from Comparative Example 4 is that the solvent was changed from toluene to hexane. A final product of 57g polyisobutylene was obtained.

[0117] The GPC analysis results of the polyisobutylene product prepared in this comparative example are attached. Figure 4 As shown in (l), through Figure 4 (l) It can be seen that the product Mn is 5449 and the molecular weight distribution is 2.07.

[0118] Comparative Example 6

[0119] The difference from Comparative Example 4 is that the amount of monotitanium phosphate was increased to 50 μmol. This resulted in 58 g of polyisobutylene product.

[0120] The GPC analysis results of the polyisobutylene product prepared in this comparative example are attached. Figure 4 As shown in (m), through Figure 4 (m) indicates that the product Mn is 3484 and the molecular weight distribution is 3.29.

[0121] Combined with appendix Figures 1-4 Based on Examples 1-8 and Comparative Examples 1-6 above, the metallocene catalyst system provided by this invention can catalyze the polymerization of isobutylene under mild conditions of 40°C to obtain medium molecular weight polyisobutylene products. These products have the characteristics of high molecular weight and narrow molecular weight distribution, and the catalyst activity is as high as 7.5 × 10⁻⁶. 6 g isobutylene / mol Cat·h -1The superior performance of this catalyst system is attributed to the stabilizing effect of the electron donor on the active center of the metallocene catalyst, which suppresses chain transfer and isomerization side reactions and enhances catalyst activity. In contrast, isobutylene polymerization using similar catalyst systems follows the traditional cationic polymerization reaction rules. Under high-temperature conditions, the cationic active centers are extremely reactive, easily undergoing chain transfer and isomerization side reactions. Therefore, under the same conditions, the resulting product has a low molecular weight, narrow distribution, and low catalyst activity.

[0122] The inventors used [2-(2,3,4,5-tetramethylcyclopentadienyl)-4-tert-butyl-6-triphenylmethylphenoxy]titanium dichloride as component A, and kept B / A, C / A, D / A and other reaction conditions the same as in Example 1. In order to further optimize the best combination catalyst system, comparative experiments were conducted using different components B, C and D, and Examples 9 to 16 were made.

[0123] The catalyst materials and product data used in Examples 9-16 are shown in Table 2 below.

[0124] Table 2. Catalyst material and product data results for Examples 9-16

[0125]

[0126]

[0127] As can be seen from the evaluation results of the catalyst system above, the product obtained by catalyzing the polymerization of isobutylene using the [2-(2,3,4,5-tetramethylcyclopentadienyl)-4-tert-butyl-6-triphenylmethylphenoxy]titanium dichloride / Ph3CB(C6F5)4 / triisobutylaluminum / MTBE combined catalyst system in Example 1 has a higher molecular weight, a narrower molecular weight distribution, and higher catalytic activity. Therefore, this combined catalyst system is preferred for further investigation of process conditions.

[0128] Using the above-mentioned preferred catalyst system, with a fixed isobutylene dosage of 100g, the inventors created Examples 17–38 by varying the molar ratios of the components in the catalyst and the polymerization reaction conditions. Specific conditions, parameters, and product data are shown in Table 3 below.

[0129] Table 3. Condition parameters and product data results for Examples 17-38

[0130]

[0131]

[0132] Analysis of the product data in Table 3 shows that by adjusting the reaction temperature, reaction time, and the amount and ratio of each component of the catalyst, the molecular weight of the product can be flexibly controlled within the range of 0–80℃. The molecular weight distribution of the product can be stabilized within 2.2, while the catalyst can maintain high catalytic activity (3 × 10⁻⁶). 4 ~8×10 6 mol isobutylene / mol Cat·h -1 ).

[0133] Based on the above embodiments and comparative experimental data, it can be seen that the technical solution is feasible and has a certain degree of advancement.

[0134] The above are merely preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. All modifications or applications made in accordance with the above embodiments are within the scope of protection of this technical solution.

[0135] Although specific embodiments of the invention have been described in detail, those skilled in the art will understand that various modifications and substitutions can be made to those details based on all the teachings disclosed, and all such changes are within the scope of protection of this invention. The full scope of this invention is given by the appended claims and any equivalents thereof.

Claims

1. Process for the preparation of polyisobutene, characterized in that, The method uses a metallocene catalyst system to catalyze the polymerization of isobutene in the preparation of polyisobutene; The metallocene catalyst system comprises four components A, B, C and D; the component A is a metallocene complex; the component B is selected from one of Ph3CB(C6F5)4, PhNMe2HB(C6F5)4, B(C6F5)3 or [(C a H 2a+1 )2NH(C b H2 b+1 )][B(C6F5)4], wherein 2≤a≤20, 1≤b≤20, and a and b are integers; the component C is an alkyl aluminum; and the component D is selected from an alkyl ether with carbon number of 2-8.

2. The method of making polyisobutylene according to claim 1, wherein, The method comprises the following steps: S1, refining of raw materials and solvents After screening isobutene and solvents, dry dehydration; S2, polymerization Under dry and anaerobic conditions, the solvents, isobutene and component C are added in sequence, stirred and mixed, the temperature is raised, and then components A, B and D are added to participate in polymerization to obtain a crude polymer product; S3, pretreatment of the crude product The crude polymer product obtained in S2 is pickled, and then subjected to alkaline washing and water washing in sequence until the water washing liquid is neutral, and the upper oil phase is obtained after standing and layering; S4, purification of the polymer product The oil phase product is subjected to vacuum distillation to obtain a polyisobutene product.

3. The method of making polyisobutylene according to claim 2, wherein, In S1, the solvents are selected from one or more of C2-C12 linear alkanes, C4-C12 isomeric alkanes, C3-C8 cycloalkanes, benzene or substituted benzene.

4. The method of making polyisobutylene of claim 2, wherein, In S2, the polymerization temperature is 0-100℃, the time is 0.1-4 h, and the pressure is 0-2 MPa.

5. The method of making polyisobutylene of claim 2, wherein, In S2, the molar ratio of component A to component B is 1:(0.5-3), the molar ratio of component A to component C is 1:(1-60), and the molar ratio of component A to component D is 1:(0.01-1).

6. The method for preparing polyisobutylene according to claim 5, characterized in that, The molar ratio of component A to component B is 1:(1-2.5), the molar ratio of component A to component C is 1:(2-40), and the molar ratio of component A to component D is 1:(0.05-1).

7. The method of claim 2, wherein the polyisobutylene is prepared by the process of claim 1. In S2, the mass ratio of isobutene to solvents is (2-12):

1.

8. The method of claim 2, wherein the polyisobutylene is prepared by the process comprising: reacting isobutylene with a catalyst to form a polyisobutylene; and removing the catalyst from the polyisobutylene. In S2, the molar ratio of isobutene to component A is (1 x 10 4 ~ 1 x 10 7 ):

1.

9. The method of claim 8, wherein the polyisobutylene is prepared by a process comprising: The molar ratio of said isobutene to said component A is (1 x 10 5 ~ 1 x 10 7 ):

1.

10. The method of claim 2, wherein the polyisobutylene is prepared by the process comprising: reacting isobutylene with a catalyst to form a polyisobutylene; and removing the catalyst from the polyisobutylene. In S4, the pressure condition of vacuum distillation is -0.1 to -0.5 MPa, and the temperature is 150-200℃.

11. The method for preparing polyisobutylene according to claim 1, characterized in that, The component A is a bridged or unbridged metallocene complex; The structural general formula (I) of the bridged component A is Cp' n (X') MX m ​ The structural general formula (II) of the non-bridged component A is Cp' n MX m ; In formula (I) and (II), Cp' is selected from substituted or unsubstituted cyclopentadienyl, indenyl, fluorenyl; M is an active center metal; X is selected from one of halogen, alkyl, alkoxy, amino or acid radical; n is 1 or 2, and m is an integer satisfying the valence state of M; X' is selected from one of SiR2, CR2, SiR2SiR2, CR2CR2, CR=CR or (CR3)2Si; R is hydrogen, or R is selected from alkyl, aryl, silyl, halogenated alkyl or halogenated aryl with less than 20 carbon atoms.

12. The method of claim 11, wherein the polyisobutylene is prepared by a process comprising: In Cp', the substituents are selected from one or more of aryloxy, substituted aryloxy, alkyl, alkoxy, silyl.

13. The method of claim 12, wherein the polyisobutylene is prepared by a process comprising: The substituted aryloxy is selected from aryloxy substituted by alkyl with 1-18 carbon atoms.

14. The method of claim 11, wherein the polyisobutylene is prepared by a process comprising: The M is selected from one of Ti, Zr or Hf.

15. The method of claim 11, wherein the polyisobutylene is prepared by a process comprising: The component A is selected from one of Cp'TiX2, Cp'ZrX2, Cp'2ZrX2, Cp'2HfX2, Cp'2(CR3)2SiZrX2.

16. The method of claim 1, wherein the polyisobutylene is prepared by the process comprising: The component B is selected from one of Ph3CB(C6F5)4, PhNMe2HB(C6F5)4 or B(C6F5)3.

17. The method for preparing polyisobutylene according to claim 1, characterized in that, The component C is a trialkyl aluminum; The trialkyl aluminum is selected from one of trimethyl aluminum, triethyl aluminum, triisopropyl aluminum, triisobutyl aluminum, tri-n-hexyl aluminum, tri-n-octyl aluminum, tri-n-decyl aluminum and tri-n-dodecyl aluminum.

18. The method of claim 17, wherein the polyisobutylene is prepared by a process comprising: The component C is selected from one of triethylaluminium, triisopropylaluminium, triisobutylaluminium, tri-n-hexylaluminium or tri-n-octylaluminium.

19. The method for preparing polyisobutylene according to claim 1, characterized in that, The component D is selected from one of dimethyl ether, diisopropyl ether, di-n-butyl ether or methyl-tert-butyl ether.

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