A metallocene catalyst carrier and its preparation method and application

Abstract

The present application relates to a metallocene catalyst carrier and its preparation method and application. The preparation method comprises the following steps: after mixing a silicon source, a hydrolysis inhibitor and water evenly, immersing a metal organic framework material, controlling the temperature not higher than 35°C for immersion treatment for 18-30h, taking out the metal organic framework material after immersion, washing and drying, and then calcining in an air atmosphere at 400-550°C, to obtain; wherein the silicon source is tetramethoxysilane or tetraethoxysilane. Thanks to the ordered pore structure and uniform chemical composition of the metal organic framework material, the carrier obtained by the above method replicates the particle morphology and pore structure of the metal organic framework material, has a uniform particle morphology and an ordered pore structure, and also makes the original metal component in the metal organic framework material in situ converted into highly dispersed metal oxide clusters embedded in the silica skeleton, which is more conducive to the uniform dispersion of the catalyst, thereby better ensuring the uniformity of the polymerization product.

Description

Technical Field

[0001] The present application relates to the field of metallocene catalyst carriers, and in particular to a metallocene catalyst carrier and a preparation method and application thereof. Background Art

[0002] In the 1980s, the emergence and rise of metallocene catalysts triggered another revolution in the polyolefin industry after the Ziegler-Natta catalyst. Metallocene catalysts are composed of transition metals or rare earth metals and at least one cyclopentadienyl or its derivative ligand, with uniform active sites, so their polymerization products usually have a narrow molecular weight distribution. In addition, the chemical structure of metallocene catalysts is easy to control, allowing us to obtain polymer products with specific properties by designing the structure of the catalyst, such as controlling molecular weight, chain structure, comonomer content, etc. Metallocene catalysts have developed rapidly in the field of polyolefins in recent decades, and can be used to prepare a variety of high-performance polymers in industrial devices, such as low-density linear polyethylene, isotactic polypropylene, polyolefin elastomers, ethylene propylene diene monomer rubber, syndiotactic polystyrene, etc. Metallocene catalysts were originally developed in a homogeneous form, and can produce extremely high activity by using them in combination with cocatalysts. However, the disadvantages of homogeneous metallocene catalysts are also very obvious, such as the difficulty in controlling the morphology of polymer particles, serious reactor sticking, low polymer bulk density, easy deactivation of active centers, and excessive use of cocatalysts. In order to solve the above problems and better adapt to the existing olefin polymerization industrial equipment, it is necessary to load the metallocene catalyst. Metallocene loading is to load the metallocene catalyst on a granular carrier by physical or chemical methods. Usually, loading will reduce the activity of the catalyst, but can obtain a polyolefin powder with regular morphology and high apparent density.

[0003] The inorganic carriers that can be used for metallocene loading mainly include: amorphous SiO2, Al2O3, magnesium chloride complex, ZrO2, zeolite and composite carriers. The organic carriers mainly include: polystyrene, polyethylene and other polymer particles. Silica has a high specific surface area, suitable pore volume and pore size, good fluidity and mechanical strength, and low cost. It can meet the needs of industrial production equipment and is also the most widely used metallocene carrier material in industry. However, the silica carrier itself also has certain defects. First, it does not have catalytic activity and has a single structural composition. It cannot produce strong interactions with metallocene compounds or co-catalysts to improve its catalytic activity. Secondly, the particles of commercial silica carriers are usually spherical, and the uniformity of their particle size is poor and the morphology is difficult to control. It is impossible to adjust the morphology and size of the catalyst according to product requirements. In addition, from the perspective of nanoscale microstructure, the pore structure uniformity of the silica carrier is poor, which will lead to insufficient uniformity of the microscopic distribution of metallocene compounds and co-catalysts, thereby affecting the uniformity of the final product structure.

[0004] At present, some work has been done to improve the shortcomings of existing silica silica carriers. Patent CN102020729A discloses a method for coating a silica gel carrier with an alumina activator. The metallocene catalyst composition prepared based on this type of Si / Al composite carrier has significantly improved activity. At the same time, adjusting the components and dosage of the coating material can adjust the molecular weight and distribution of the final polymerization product. Patent CN107459592A discloses a method for preparing a silica gel carrier modified with manganese chloride and a supported metallocene catalyst thereof. When used for olefin polymerization, it can significantly improve the activity of the catalytic reaction and keep the molecular weight distribution and bulk density of the polymer obtained by the original metallocene catalyst (without adding manganese chloride) basically unchanged. However, the modified components used in the above-mentioned modified silica gel carrier are large in amount, disordered in distribution, and low in atomic utilization, and the addition of these modified components will also lead to a decrease in the specific surface area of ​​the initial silica gel carrier. In addition, although this type of modification method achieves the improvement of catalyst activity by introducing additional guest components, it does not achieve effective regulation of the carrier pore structure and morphology. Therefore, there is an urgent need to develop more efficient carrier preparation methods to achieve controllable preparation of metallocene catalyst carrier structure and morphology, so as to achieve precise regulation of the structure and performance of polyolefin products. Summary of the invention

[0005] The present invention provides a method for preparing a metallocene catalyst carrier. By adopting the method, a variety of silica carriers with different structures and compositions can be simply prepared by regulating MOFs, thereby achieving precise regulation of the carrier morphology and size. The preparation method is simple and easy to operate, and is convenient for industrial preparation.

[0006] The present invention also provides a metallocene catalyst carrier having a uniform particle morphology and an ordered pore structure, which can ensure the uniformity of the microscopic distribution of the metallocene catalyst and the co-catalyst, thereby ensuring better uniformity of the polymerization product.

[0007] The present invention also provides a supported catalyst, in which the metallocene catalyst and the co-catalyst are well distributed on the carrier and can better ensure the uniformity of the polymerized product.

[0008] The invention also provides a method for catalyzing olefin polymerization. The polyolefin product prepared by the method has good structural uniformity.

[0009] The invention provides a method for preparing a metallocene catalyst carrier, comprising the following steps: uniformly mixing a silicon source, a hydrolysis inhibitor and water, then immersing a metal organic framework material with the silicon source, controlling the temperature to be no higher than 35°C for immersion treatment for 18-30 hours, taking out the metal organic framework material after immersion, washing and drying, and then calcining in an air atmosphere at 400-550°C to obtain the metallocene catalyst carrier; wherein the silicon source is tetramethoxysilane or tetraethoxysilane.

[0010] According to the above-mentioned method for preparing the metallocene catalyst carrier, the volume ratio of the silicon source to the hydrolysis inhibitor is 2-8:1.

[0011] According to the above-mentioned method for preparing the metallocene catalyst carrier, the usage ratio of the metal organic framework material to the silicon source is 100 mg: 0.5-1 mL.

[0012] According to the above-mentioned method for preparing the metallocene catalyst carrier, the volume ratio of the silicon source to water is 6-30:1.

[0013] According to the above-mentioned method for preparing the metallocene catalyst carrier, the volume ratio of the silicon source to the hydrolysis inhibitor is 4-8:1.

[0014] According to the above-mentioned preparation method of the metallocene catalyst carrier, calcination is carried out at 450-550°C for 0.5-1.5h.

[0015] According to the above-mentioned preparation method of the metallocene catalyst carrier, the hydrolysis inhibitor is an alcohol hydrolysis inhibitor.

[0016] According to the preparation method of the metallocene catalyst carrier described above, the metal organic framework material is any one of UiO-66, UiO-67, hcp UiO-66, hcp UiO-67, MOF-74, MOF-808, MOF-333, MOF-519, ZIF-8, ZIF-90, ZIF-67, MIL-53, MIL-68, MIL-88B, MIL-96, MIL-100, MIL-101, MIL-110, MIL-140A, CAU-1, CAU-3, CAU-10, CAU-16, DUT-4, DUT-5, NU-2000, and PCN-333.

[0017] According to the above-mentioned preparation method of the metallocene catalyst carrier, the hydrolysis inhibitor is one or more of methanol, ethanol and butanol.

[0018] According to the above-mentioned preparation method of the metallocene catalyst carrier, the metal organic framework material is MIL-100-Al, MIL-100-Fe, MIL-96-Al, MIL-110-Al, and UiO-66-Zr.

[0019] The present invention also provides a metallocene catalyst carrier, which is prepared by the above method.

[0020] The present invention also provides a supported catalyst, comprising a metallocene catalyst and a co-catalyst supported on the above metallocene catalyst carrier.

[0021] The supported catalyst described above is obtained by reacting a support, a co-catalyst methylaluminoxane, and a metallocene catalyst rac-Et(Ind)2ZrCl2 in a toluene solvent at 40±5°C for 2-4h, separating the solid and draining it.

[0022] According to the supported catalyst described above, in the reaction solution, the mass ratio of the support, the co-catalyst methylaluminoxane, and the metallocene catalyst rac-Et(Ind)2ZrCl2 is 1-3:1:0.05-0.15.

[0023] The present invention also provides a method for catalyzing olefin polymerization, which at least comprises using the above-mentioned supported catalyst for catalysis.

[0024] According to the above-mentioned method for catalytic olefin polymerization, the olefin is propylene, and propylene is reacted at 70±5° C. for 0.5-1.5 hours under the action of hydrogen, triethylaluminum and a supported catalyst to obtain a polypropylene product.

[0025] The preparation method of the metallocene catalyst carrier provided by the present invention is a method for preparing a highly dispersed metal oxide and silicon dioxide composite material based on the nanocasting technology of metal organic framework materials. Thanks to the orderly pore structure and uniform chemical composition of MOFs materials, the new silicon dioxide carrier obtained by the above method replicates the particle morphology and pore structure of MOFs, has a uniform particle morphology and an ordered pore structure, and also enables the original metal components in MOFs to be in situ converted into highly dispersed metal oxide clusters embedded in the silicon dioxide skeleton, which is more conducive to the dispersion of the catalyst, thereby better ensuring the uniformity of the polymerization product. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a schematic diagram of the preparation process of the metallocene catalyst carrier of the present invention;

[0027] Figure 2 is a scanning electron microscope image of the metallocene catalyst support in Example 4 of the present invention;

[0028] Figure 3 is the pore size distribution result of the metallocene catalyst support in Example 4 of the present invention;

[0029] Figure 4 is a scanning electron microscope image of the metallocene catalyst support in Example 11 of the present invention;

[0030] Figure 5 is a scanning electron microscope image of the metallocene catalyst support in Example 12 of the present invention;

[0031] Figure 6 This is a scanning electron microscope image of the metallocene catalyst support in Example 14 of the present invention. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical solutions and advantages of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in combination with the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0033] A method for preparing a metallocene catalyst carrier comprises the following steps: uniformly mixing a silicon source, a hydrolysis inhibitor and water, then immersing a metal organic framework material with the silicon source, controlling the temperature to be no higher than 35°C for 18-30h of immersion treatment, taking out the metal organic framework material after immersion, washing and drying it, and then calcining it in an air atmosphere at 400-550°C to obtain the metallocene catalyst carrier; wherein the silicon source is tetramethoxysilane or tetraethoxysilane.

[0034] In view of the shortcomings of traditional metallocene catalysts, such as the difficulty in regulating the morphology of carrier particles and poor order of microscopic pores, the present invention provides a method for preparing highly dispersed metal oxide and silica composite materials based on the nanocasting technology of metal organic framework materials. Thanks to the orderly pore structure and uniform chemical composition of MOFs materials, the new silica carrier obtained by the above method replicates the particle morphology and pore structure of MOFs, has a uniform particle morphology and an ordered pore structure, and also enables the original metal components in MOFs to be in situ converted into highly dispersed metal oxide clusters embedded in the silica skeleton, which is more conducive to the uniform dispersion of the catalyst and better guarantee of the uniformity of the polymerization product. By regulating MOFs, it is relatively easy to prepare a variety of silica carriers with different structures and compositions, and achieve precise regulation of the carrier morphology and size.

[0035] In the present invention, the volume ratio of the silicon source to the hydrolysis inhibitor is usually controlled to be 2-8:1. Further studies have found that when the volume ratio of the silicon source to the hydrolysis inhibitor is relatively low (lower than 4:1), the supported catalyst prepared by the obtained carrier has a more obvious advantage in regulating the uniformity of the product. When the volume ratio of the silicon source to the hydrolysis inhibitor is controlled to be 4-8:1, the supported catalyst prepared by the obtained carrier not only has the advantage of regulating the uniformity of the product, but also its catalytic activity is significantly improved. This may be because at this ratio, the hydrolysis rate of the silicon source is moderate, which can ensure that the silicon source is fully impregnated into the pores of the MOFs and then completely hydrolyzed, so that the morphology of the carrier particles and the pore structure after the final calcination are better and the orderliness of the catalyst is more uniform, so that the performance of the supported catalyst is also better.

[0036] During the impregnation treatment, in order to ensure that the silicon source can be fully impregnated into the pores of MOFs, the amount ratio of the metal organic framework material to the silicon source is usually controlled to be 100 mg: 0.5-1 mL. There is no special restriction on the volume ratio of the silicon source to water in the impregnation solution, which is usually controlled at 6-30:1.

[0037] During the immersion treatment, for ease of operation, the temperature is usually controlled to be no higher than 35°C and the immersion time is 18-30 hours. More specifically, the immersion temperature is controlled to be 25±5°C and the immersion time is 22-26 hours, which is simpler to operate. In some specific embodiments, the temperature is controlled to be 25°C and the immersion treatment is performed for 24 hours.

[0038] During the calcination treatment, when the calcination temperature is too high (above 550°C), the metal oxide clusters in the MOFs material will agglomerate, which will lead to a decrease in the number of available metal sites in the carrier and a decrease in the uniformity of the distribution, so that the sites that can interact with the metallocene catalyst in the final supported catalyst will also be reduced, and the uniformity of the active sites will also be reduced, so the polymerization activity will be reduced and the molecular weight distribution of the polymer product will also be poor. Therefore, in this application, it is necessary to control the calcination temperature at 400-550°C, and the calcination time is usually controlled at 0.5-1.5h. Studies have found that when the calcination temperature is 450-550°C and the calcination time is 0.5-1.5h, the performance is better. For example, in some specific embodiments, the calcination temperature is 500°C and the calcination treatment is 1h.

[0039] The addition of a hydrolysis inhibitor can control the hydrolysis rate of the silicon source, thereby making the impregnation process of the silicon source and the MOFs material more complete. In the present invention, alcohols can be selected as hydrolysis inhibitors because alcohols can react with partially hydrolyzed silicon sources to form alkoxy silicon, thereby effectively inhibiting hydrolysis. For example, in some specific embodiments, the hydrolysis inhibitor is one or more of methanol, ethanol, and butanol.

[0040] The morphology and composition of the metal organic framework also affect the performance of the finally prepared carrier. In the present invention, the metal organic framework material can be selected from any one of UiO-66, UiO-67, hcp UiO-66, hcp UiO-67, MOF-74, MOF-808, MOF-333, MOF-519, ZIF-8, ZIF-90, ZIF-67, MIL-53, MIL-68, MIL-88B, MIL-96, MIL-100, MIL-101, MIL-110, MIL-140A, CAU-1, CAU-3, CAU-10, CAU-16, DUT-4, DUT-5, NU-2000, and PCN-333. Considering the structural stability and preparation cost, metal organic framework materials are usually selected from any one of UiO-66-Zr, hcp UiO-66-Zr, MIL-53-Al, MIL-96-Al, MIL-100-Al, MIL-100-Fe, MIL-101-Al, MIL-110-Al, ZIF-8-Zn, and MIL-140A-Zr.

[0041] However, the study found that when the metal organic framework is selected from MIL-100-Al, MIL-100-Fe, MIL-96-Al, MIL-110-Al, and UiO-66-Zr, the performance of the carrier is better, and the finally prepared supported catalyst has better catalytic activity and uniformity of catalytic products.

[0042] The present invention also provides a metallocene catalyst carrier, which is prepared by the above method.

[0043] The present invention also provides a supported catalyst, which includes a metallocene catalyst and a co-catalyst supported on the metallocene catalyst support. Since the supported catalyst has a uniform particle morphology and an ordered pore structure, the metallocene catalyst and the co-catalyst can be evenly distributed, thereby well ensuring the uniformity of the catalytic product.

[0044] In some specific embodiments, the supported catalyst is obtained by reacting a carrier, a co-catalyst methylaluminoxane, and a metallocene catalyst rac-Et(Ind)2ZrCl2 in a toluene solvent at 40±5°C for 2-4h, separating the solid and draining it. In the reaction solution, the mass ratio of the carrier, the co-catalyst methylaluminoxane, and the metallocene catalyst rac-Et(Ind)2ZrCl2 is 1-3:1:0.05-0.15, for example, the mass ratio of the three is 2:1:0.1.

[0045] The present invention also provides a method for catalyzing olefin polymerization, which at least comprises using the above-mentioned supported catalyst for catalytic polymerization. The polymer product prepared by the method has good uniformity and narrow molecular weight distribution, and the method (or the supported catalyst used) has excellent hydrogen modulation sensitivity.

[0046] In some specific embodiments, when the olefin is propylene, the propylene is reacted in the presence of hydrogen, triethylaluminum and a supported catalyst at 70±5° C. for 0.5-1.5 h to obtain a polypropylene product.

[0047] For example, in some specific embodiments, the concentration of hydrogen is 0-300 ppm, the amount of propylene used is 1.5 Kg, the amount of triethylaluminum used is 2 mL, and the amount of supported catalyst used is 100 mg.

[0048] The preparation method of the metallocene catalyst carrier of the present invention is described in detail below in conjunction with specific examples.

[0049] Example 1

[0050] S1. Take tetramethoxysilane (6 mL), methanol (3 mL) and H2O (1 mL), add them into a glass bottle and ultrasonicate for five minutes to make them dispersed evenly.

[0051] S2. Weigh MIL-100-Al (0.6 g) and add it to the mixed solution obtained in S1. Ultrasonicate again for five minutes to fully immerse the MOF sample in the mixed solution. Seal the glass bottle and let it stand at 25 °C for 24 h to ensure that the SiO2 precursor fully enters the MOF pores. Then centrifuge the solid sample and wash it with methanol to remove excess methoxysilane. The sample washed with methanol is dried at 60 °C.

[0052] S3. Place the solid sample obtained in S2 in a magnetic boat and put it into a tube furnace. Heat it to 500 °C at a heating rate of 2 °C / min in an air atmosphere and keep it for 1 h. After cooling to room temperature, take out the obtained powder, which is the final carrier material.

[0053] Metallocene loading test: 2 g of the support material obtained in S3 was dispersed in 15 mL of toluene, and 10 mL of methylaluminoxane (MAO) toluene solution (0.1 g / mL) and 100 mg of rac-Et(Ind)2ZrCl2 were added thereto. The mixture was stirred at 40 °C for 3 h. After the reaction, the solid was separated by sedimentation and washed three times with toluene solution. Finally, the solid was drained to obtain the final supported catalyst.

[0054] Propylene polymerization test: The 5L polymerization kettle was purged and replaced with dry nitrogen for more than 5 times, and hydrogen (160 ppm), propylene (1.5 Kg), triethylaluminum impurity remover (2 mL) and loaded metallocene catalyst (100 mg) were added into the reactor. Then the temperature was raised to 70 °C for 1 h. After the device was cooled to room temperature, the discharged material was dried to obtain a polypropylene product, the calculated activity by weight was 3540 gPP / gCat, and the molecular weight distribution of the product was 2.6.

[0055] Example 2

[0056] The method of Example 1 was used for carrier preparation, metallocene loading and propylene polymerization, except that the amounts of tetramethoxysilane, methanol and water used in the carrier preparation process were 6 mL, 3 mL and 0.5 mL, respectively. The final polymerization activity of the catalyst was 5688 gPP / gCat, and the molecular weight distribution of the product was 2.5.

[0057] Example 3

[0058] The method of Example 1 was used for carrier preparation, metallocene loading and propylene polymerization, except that the amounts of tetramethoxysilane, methanol and water used in the carrier preparation process were 6 mL, 3 mL and 0.2 mL, respectively. The final polymerization activity of the catalyst was 4739 gPP / gCat, and the molecular weight distribution of the product was 2.7.

[0059] Example 4

[0060] The method of Example 1 was used for carrier preparation, metallocene loading and propylene polymerization, except that the amounts of tetramethoxysilane, methanol and water used in the carrier preparation process were 6 mL, 1.5 mL and 0.5 mL, respectively. The final polymerization activity of the catalyst was a maximum of 13400 gPP / gCat, and the molecular weight distribution of the product was 3.0. Figure 2 is a scanning electron microscope image of the metallocene catalyst support obtained in this example, Figure 3 The pore size distribution result is measured by nitrogen adsorption and desorption. From the above results, it can be seen that the obtained metallocene catalyst carrier has a uniform particle morphology and an ordered pore structure.

[0061] Example 5

[0062] The method of Example 1 was used for carrier preparation, metallocene loading and propylene polymerization, except that the amounts of tetramethoxysilane, methanol and water used in the carrier preparation process were 6 mL, 0.75 mL and 0.5 mL, respectively. The final polymerization activity of the catalyst was 11050 gPP / gCat, and the molecular weight distribution of the product was 2.8.

[0063] Example 6

[0064] The method of Example 4 was used for carrier preparation, metallocene loading and propylene polymerization, except that the amounts of tetramethoxysilane, methanol and water used in the carrier preparation process were 6 mL, 1.5 mL and 0.3 mL, respectively. The final polymerization activity of the catalyst was 12200 gPP / gCat, and the molecular weight distribution of the product was 3.1.

[0065] Example 7

[0066] The method of Example 5 was used for carrier preparation, metallocene loading and propylene polymerization, except that the amounts of tetramethoxysilane, methanol and water used in the carrier preparation process were 6 mL, 0.75 mL and 0.2 mL, respectively. The final polymerization activity of the catalyst was 9970 gPP / gCat, and the molecular weight distribution of the product was 2.9.

[0067] Example 8

[0068] The method of Example 4 was used to prepare the carrier, load the metallocene and polymerize propylene, except that the silicon source was tetraethoxysilane. The polymerization activity of the final catalyst was 6640 gPP / gCat, and the molecular weight distribution of the product was 3.2.

[0069] Example 9

[0070] The method of Example 4 was used for carrier preparation, metallocene loading and propylene polymerization, except that butanol was used as the hydrolysis inhibitor. The polymerization activity of the final catalyst was 9810 gPP / gCat, and the molecular weight distribution of the product was 2.8.

[0071] Example 10

[0072] The method of Example 4 was used for carrier preparation, metallocene loading and propylene polymerization, except that MIL-100-Fe was used as the MOF precursor. The final polymerization activity of the catalyst was 5963 gPP / gCat, and the molecular weight distribution of the product was 2.6.

[0073] Embodiment 11

[0074] The method of Example 4 was used for carrier preparation, metallocene loading and propylene polymerization, except that MIL-96-Al was used as the MOF precursor. The final polymerization activity of the catalyst was 8165 gPP / gCat, and the molecular weight distribution of the product was 2.7. Figure 4 This is a scanning electron microscope image of the metallocene catalyst support obtained in this example.

[0075] Example 12

[0076] The method of Example 4 was used for carrier preparation, metallocene loading and propylene polymerization, except that MIL-53-Al was used as the MOF precursor. The final polymerization activity of the catalyst was 3550 gPP / gCat, and the molecular weight distribution of the product was 2.3. Figure 5 This is a scanning electron microscope image of the metallocene catalyst support obtained in this example.

[0077] Embodiment 13

[0078] The method of Example 4 was used for carrier preparation, metallocene loading and propylene polymerization, except that MIL-110-Al was used as the MOF precursor. The final polymerization activity of the catalyst was 7277 gPP / gCat, and the molecular weight distribution of the product was 2.9.

[0079] Embodiment 14

[0080] The method of Example 4 was used for carrier preparation, metallocene loading and propylene polymerization, except that UiO-66-Zr was used as the MOF precursor. The final polymerization activity of the catalyst was 7534 gPP / gCat, and the molecular weight distribution of the product was 2.7. Figure 6 This is a scanning electron microscope image of the metallocene catalyst support obtained in this example.

[0081] Embodiment 15

[0082] The method of Example 4 was used for carrier preparation, metallocene loading and propylene polymerization, except that hcp UiO-66-Zr was used as the MOF precursor. The polymerization activity of the final catalyst was 5066 gPP / gCat, and the molecular weight distribution of the product was 2.5.

[0083] Example 16

[0084] The method of Example 4 was used for carrier preparation, metallocene loading and propylene polymerization, except that MIL-140A-Zr was used as the MOF precursor. The final polymerization activity of the catalyst was 4709 gPP / gCat, and the molecular weight distribution of the product was 3.0.

[0085] Embodiment 17

[0086] The method of Example 4 was used for carrier preparation, metallocene loading and propylene polymerization, except that ZIF-8-Zn was used as the MOF precursor. The final polymerization activity of the catalyst was 5241 gPP / gCat, and the molecular weight distribution of the product was 3.3.

[0087] Embodiment 18

[0088] The method of Example 4 was used for carrier preparation, metallocene loading and propylene polymerization, except that the calcination temperature of the carrier was 400° C. The final polymerization activity of the catalyst was 12053 gPP / gCat, and the molecular weight distribution of the product was 3.2.

[0089] Embodiment 19

[0090] The method of Example 4 was used to prepare the carrier, load the metallocene and polymerize propylene, except that hydrogen was not introduced during the polymerization process. The final polymerization activity of the catalyst was 3580 gPP / gCat, and the molecular weight distribution of the product was 2.4.

[0091] Embodiment 20

[0092] The method of Example 4 was used for carrier preparation, metallocene loading and propylene polymerization, except that the hydrogen concentration during the polymerization process was 200 ppm. The final polymerization activity of the catalyst was 9357 gPP / gCat, and the molecular weight distribution of the product was 2.6.

[0093] Embodiment 21

[0094] The method of Example 4 was used to prepare the carrier, load the metallocene and polymerize propylene. The hydrogen concentration in different polymerization processes was 300 ppm. The final polymerization activity of the catalyst was 7660 gPP / gCat, and the molecular weight distribution of the product was 2.3.

[0095] Comparative Example 1

[0096] The method of Example 4 was used to carry out metallocene loading and propylene polymerization, except that the MOF carrier was not nanocasted but directly used as a catalyst carrier. The final polymerization activity of the catalyst was 4338 gPP / gCat, and the molecular weight distribution of the product was 3.3.

[0097] Comparative Example 2

[0098] The method of Example 4 was used for metallocene loading and propylene polymerization, except that the MOF carrier MIL-100-Al was used as a catalyst carrier directly after calcination at 500°C without impregnation treatment. The final polymerization activity of the catalyst was 2360 gPP / gCat, and the molecular weight distribution of the product was 3.4.

[0099] Comparative Example 3

[0100] The method of Example 4 was used to carry out metallocene loading and propylene polymerization, except that the commercial silica gel carrier SYLOPOL 2212D was used as the carrier. The final polymerization activity of the catalyst was 2708 gPP / gCat, and the molecular weight distribution of the product was 3.5.

[0101] Comparative Example 4

[0102] The method of Example 4 was used for metallocene loading and propylene polymerization, except that the mixed solution in step S1 did not contain methanol as a hydrolysis inhibitor (i.e., tetramethoxysilane aqueous solution was used for impregnation treatment). The final polymerization activity of the catalyst was 4320 gPP / gCat, and the molecular weight distribution of the product was 3.3.

[0103] Comparative Example 5

[0104] The method of Example 4 was used to carry out metallocene loading and propylene polymerization, except that MOF was directly immersed in tetramethoxysilane and calcined. The final polymerization activity of the catalyst was 5520 gPP / gCat, and the molecular weight distribution of the product was 4.0.

[0105] Comparative Example 6

[0106] The method of Example 4 was used for carrier preparation, metallocene loading and propylene polymerization, except that the calcination temperature of the carrier was 600° C. The final polymerization activity of the catalyst was 11560 gPP / gCat, and the molecular weight distribution of the product was 3.5.

[0107] Comparative Example 7

[0108] The method of Example 4 was used for carrier preparation, metallocene loading and propylene polymerization, except that the calcination temperature of the carrier was 800° C. The final polymerization activity of the catalyst was 7033 gPP / gCat, and the molecular weight distribution of the product was 3.8.

[0109] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing a metallocene catalyst carrier, characterized in that: The method comprises the following steps: mixing a silicon source, a hydrolysis inhibitor and water evenly, then immersing the silicon source, a hydrolysis inhibitor and water in a metal organic framework material, controlling the temperature to be no higher than 35°C for immersion treatment for 18-30 hours, taking out the metal organic framework material after immersion, washing and drying it, and then calcining it in an air atmosphere at 400-550°C to obtain a metallocene catalyst carrier; Wherein, the silicon source is tetramethoxysilane or tetraethoxysilane, the hydrolysis inhibitor is an alcohol hydrolysis inhibitor, and the metal organic framework material is any one of UiO-66, UiO-67, hcp UiO-66, hcp UiO-67, MOF-74, MOF-808, MOF-333, MOF-519, ZIF-8, ZIF-90, ZIF-67, MIL-53, MIL-68, MIL-88B, MIL-96, MIL-100, MIL-101, MIL-110, MIL-140A, CAU-1, CAU-3, CAU-10, CAU-16, DUT-4, DUT-5, NU-2000, and PCN-333; The volume ratio of the silicon source to the hydrolysis inhibitor is (2-8):1, the usage ratio of the metal organic framework material to the silicon source is 100 mg:(0.5-1 mL), and the volume ratio of the silicon source to water is (6-30):

1.

2. The method for preparing a metallocene catalyst carrier according to claim 1, characterized in that: The calcination conditions are: 450-550°C, calcination for 0.5-1.5h.

3. The method for preparing a metallocene catalyst carrier according to claim 1 or 2, characterized in that: The hydrolysis inhibitor is one or more of methanol, ethanol and butanol.

4. The method for preparing a metallocene catalyst carrier according to claim 1, characterized in that: The metal organic framework materials are MIL-100-Al, MIL-100-Fe, MIL-96-Al, MIL-110-Al, and UiO-66-Zr.

5. A metallocene catalyst carrier, characterized in that: The invention is prepared by the preparation method according to any one of claims 1 to 4.

6. A supported catalyst, characterized in that The invention comprises a metallocene catalyst and a co-catalyst supported on the metallocene catalyst carrier according to claim 5.

7. The supported catalyst according to claim 6, characterized in that The supported catalyst is obtained by reacting a carrier, a co-catalyst methylaluminoxane, and a metallocene catalyst rac-Et(Ind)2ZrCl2 in a toluene solvent at 40±5°C for 2-4h, separating the solid and draining it; and / or In the reaction solution, the mass ratio of the carrier, the co-catalyst methylaluminoxane and the metallocene catalyst rac-Et(Ind)2ZrCl2 is 1-3:1:0.05-0.

15.

8. A method for catalyzing olefin polymerization, characterized in that: The method at least comprises using the supported catalyst described in claim 6 or 7 for catalysis.

9. The method for catalyzing olefin polymerization according to claim 8, characterized in that: The olefin is propylene, and propylene is reacted at 70±5° C. for 0.5-1.5 h under the action of hydrogen, triethylaluminum and a supported catalyst to obtain a polypropylene product.

Images