Silicon-magnesium composite Ziegler-Natta catalyst carrier and preparation method thereof
The silicon-magnesium composite Ziegler-Natta catalyst support was prepared by spray drying, which solved the problem of insufficient morphology and particle size uniformity of the existing support, achieved improvements in catalyst activity and polymerization product performance, and was suitable for industrial-scale production.
Patent Information
- Application Number
- CN202510505401.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-22
- Publication Date
- 2025-06-24
AI Technical Summary
The existing Ziegler-Natta catalyst support has problems of insufficient morphological perfection and particle size uniformity, which affects the activity of the catalyst and the performance of the polymerization product.
Silicic acid sol was prepared by spray drying, and porous silicon spheres were obtained after aging and calcination, and then loaded with a magnesium source and surface treatment to prepare a silicon-magnesium composite Ziegler-Natta catalyst support.
The morphological perfection and particle size uniformity of the catalyst support are improved, and the magnesium loading effect is better. It is suitable for industrial-scale polypropylene catalyst production, improving the activity of the catalyst and the performance of the polymerization product.
Smart Images
Figure CN120192441A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of catalyst preparation, and particularly relates to a silicon-magnesium composite Ziegler-Natta catalyst support prepared by spray drying and a preparation method thereof, which are applicable to the production of polypropylene catalysts on an industrial scale. Background Art
[0002] Ziegler-Natta catalysts are one of the most widely used catalysts in olefin polymerization reactions. So far, they have developed through five generations, and their performance depends to a large extent on the properties of the support. Traditional Ziegler-Natta catalyst supports are mostly magnesium chloride, which have disadvantages such as low specific surface area, low effective titanium loading rate, uneven pore structure, and poor mechanical strength, affecting the activity of the catalyst and the properties of the polymerization product.
[0003] In recent years, porous silicon spheres, as a new type of catalyst support material, have received extensive attention due to their advantages such as large specific surface area, controllable pore structure, and high mechanical strength. However, there are still significant gaps in the preparation of high-end silica gel products. Most of the preparation methods of porous silicon spheres after silica gel treatment are complex in process and high in cost, making it difficult to achieve large-scale industrial production. Summary of the Invention
[0004] (1) Technical Problems to be Solved
[0005] The present invention provides a silicon-magnesium composite Ziegler-Natta catalyst support and a preparation method thereof to solve the technical problems of insufficient perfection of morphology and uniformity of particle size in existing preparation technologies. The prepared catalyst support has a more perfect morphology, more uniform particle size, and better magnesium loading effect.
[0006] (2) Technical Solutions
[0007] To solve the above technical problems, the present invention provides a preparation method of a silicon-magnesium composite Ziegler-Natta catalyst support, which includes the following steps:
[0008] S1. Prepare silica sol: Mix a silicon source, a template agent, an acid catalyst, and water, and stir evenly to obtain silica sol;
[0009] S2. Spray drying: Perform spray drying on the silica sol obtained in step S1 to obtain a spherical silica gel support;
[0010] S3. Aging: Age the spherical silica gel support obtained in step S2 to further condense the spherical silica gel support;
[0011] S4. Calcination: Calcinate the spherical silica gel support obtained in step S3 in an air atmosphere to remove the template agent and obtain a porous silicon sphere;
[0012] S5. Magnesium source loading: Place the porous silicon spheres obtained in step S4 into a single-necked flask, add an aqueous solution of soluble magnesium salt to the flask, stir magnetically at room temperature, and use a rotary evaporator to rotary evaporate in a nitrogen stream until the water is completely evaporated to obtain porous silicon spheres loaded with a magnesium source;
[0013] S6. Surface treatment: Use an organosilane coupling agent to perform surface treatment on the porous silicon spheres loaded with a magnesium source obtained in step S5 to obtain a silicon-magnesium composite Ziegler-Natta catalyst support.
[0014] Further, in step S1, the silicon source is one or more of tetraethyl orthosilicate, sodium silicate, and silica sol; the template agent is one or more of cetyltrimethylammonium bromide, polyethylene glycol, and block copolymer; the acid catalyst is one or more of hydrochloric acid, perchloric acid, and sulfuric acid.
[0015] Further, in step S1, the molar ratio of the silicon source, the template agent, and the acid catalyst is 2:(1 - 4):(1 - 4).
[0016] Further, in step S2, the inlet temperature of spray drying is 150 - 250 °C, and the outlet temperature is 80 - 120 °C.
[0017] Further, in step S3, the aging temperature is 40 - 80 °C, and the aging time is 12 - 48 hours.
[0018] Further, in step S4, the calcination temperature is 500 - 800 °C, and the calcination time is 2 - 6 hours.
[0019] Further, in step S5, the magnesium salt is one or more of magnesium acetate, magnesium citrate, and magnesium chloride; the concentration of the aqueous magnesium salt solution is 0.25 - 1 M, and n(Mg):n(Si) = 5% - 15%.
[0020] Further, in step S5, the stirring time at room temperature is 4 - 8 h, and the rotary evaporation heating temperature is 100 °C.
[0021] Further, in step S6, the organosilane coupling agent is one or more of methyltriethoxysilane, phenyltriethoxysilane, and vinyltriethoxysilane.
[0022] In addition, the present invention also provides a silicon-magnesium composite Ziegler-Natta catalyst support, which is prepared by the above method.
[0023] (III) Beneficial effects
[0024] The present invention provides a silicon-magnesium composite Ziegler-Natta catalyst support and a preparation method thereof. A spherical silica gel support is prepared by spray drying, and then a porous silicon sphere with good morphology and pore structure is obtained after high-temperature activation. Then, a magnesium source is loaded, and finally, the silicon-magnesium composite Ziegler-Natta catalyst support is prepared, successfully solving the deficiencies in the perfection of morphology and particle size uniformity in the existing preparation technology. The present invention provides a process that is simple, easy to operate, low in cost, and easy to industrialize. The prepared porous silicon spheres have the advantages of large specific surface area, controllable pore structure, high mechanical strength, etc. The prepared silicon-magnesium composite Ziegler-Natta catalyst support is used in olefin polymerization reactions and has the advantages of high effective titanium loading rate, good perfection of polymerization products and other properties. BRIEF DESCRIPTION OF THE DRAWINGS
[0025] Figures 1a to 1c They are TEM images of the silicon-magnesium composite Ziegler-Natta catalyst supports prepared in Examples 1 to 3, respectively. DETAILED DESCRIPTION OF THE EMBODIMENTS
[0026] To make the objectives, contents, and advantages of the present invention clearer, the following further describes the specific embodiments of the present invention in detail with reference to the drawings and examples.
[0027] Example 1
[0028] S1. Tetraethyl orthosilicate, cetyltrimethylammonium bromide, and concentrated hydrochloric acid are mixed with 200 g of water in a molar ratio of 1:1:2 and stirred evenly to obtain a silica sol.
[0029] S2. The silica sol obtained in step S1 is spray-dried with an inlet temperature of 200 °C and an outlet temperature of 100 °C to obtain a spherical silica gel support.
[0030] S3. The spherical silica gel support obtained in step S2 is aged for 24 hours at 60 °C and a relative humidity of 80%.
[0031] S4. The aged spherical silica gel support in step S3 is calcined in an air atmosphere at 600 °C for 4 hours to obtain a porous silicon sphere.
[0032] S5. A certain amount of the porous silicon spheres obtained in step S4 is placed in a single-neck flask, and 1 M magnesium acetate solution is added to the flask, where n(Mg):n(Si) = 1:10. Magnetic stirring is carried out at room temperature for 6 h, and rotary evaporation is carried out in a nitrogen stream using a rotary evaporator at a temperature of 100 °C until the water is completely evaporated to obtain a porous silicon sphere loaded with a magnesium source, which is placed in a glove box for standby.
[0033] S6. The porous silicon spheres loaded with magnesium source obtained in step S5 are surface-treated with methyltriethoxysilane, then thoroughly washed with hexane and dried under vacuum at 70 °C to finally obtain a silicon-magnesium composite Ziegler-Natta catalyst support.
[0034] The properties of the porous silicon spheres obtained in step S4 are shown in Table 1, and the TEM image of the silicon-magnesium composite Ziegler-Natta catalyst support finally obtained in step S6 is as Figure 1a shown.
[0035] Example 2
[0036] S1. Sodium silicate, polyethylene glycol, and perchloric acid are mixed with 200 g of water at a molar ratio of 2:1:2 and stirred evenly to obtain a silica sol.
[0037] S2. The silica sol obtained in step S1 is spray-dried at an inlet temperature of 180 °C and an outlet temperature of 90 °C to obtain spherical silica supports.
[0038] S3. The spherical silica supports obtained in step S2 are aged for 36 hours at 50 °C and a relative humidity of 70%.
[0039] S4. The spherical silica supports aged in step S3 are calcined at 700 °C for 3 hours in an air atmosphere to obtain porous silicon spheres.
[0040] S5. A certain amount of the porous silicon spheres obtained in step S4 is placed in a single-neck flask, and a 1 M magnesium citrate solution is added to the flask, where n(Mg):n(Si) = 1:10. Magnetic stirring is carried out at room temperature for 6 h, and rotary evaporation is carried out in a nitrogen stream using a rotary evaporator at a temperature of 100 °C until the water is completely evaporated to obtain porous silicon spheres loaded with magnesium source, which are placed in a glove box for standby.
[0041] S6. The porous silicon spheres loaded with magnesium source obtained in step S5 are surface-treated with phenyltriethoxysilane, then thoroughly washed with hexane and dried under vacuum at 70 °C to finally obtain a silicon-magnesium composite Ziegler-Natta catalyst support.
[0042] The properties of the porous silicon spheres obtained in step S4 are shown in Table 1, and the TEM image of the silicon-magnesium composite Ziegler-Natta catalyst support finally obtained in step S6 is as Figure 1b shown.
[0043] Example 3
[0044] S1. Colloidal silica, block copolymer, and dilute sulfuric acid are mixed with 200 g of water at a molar ratio of 2:1:1 and stirred evenly to obtain a silica sol.
[0045] S2. Spray-dry the silica sol obtained in step S1 at an inlet temperature of 220 °C and an outlet temperature of 110 °C to obtain a spherical silica gel support;
[0046] S3. Age the spherical silica gel support obtained in step S2 at 70 °C and a relative humidity of 90% for 18 hours;
[0047] S4. Calcinate the aged spherical silica gel support obtained in step S3 at 550 °C in an air atmosphere for 5 hours to obtain a porous silicon sphere;
[0048] S5. Take a certain amount of the porous silicon spheres obtained in step S4 and place them in a single-neck flask. Add a 1M magnesium chloride solution to the flask, where n(Mg):n(Si) = 1:10, and stir magnetically at room temperature for 6 h. Use a rotary evaporator to evaporate in a nitrogen stream at a temperature of 100 °C until all the water is completely evaporated to obtain a porous silicon sphere loaded with a magnesium source, and place it in a glove box for standby;
[0049] S6. Surface-treat the porous silicon sphere loaded with a magnesium source obtained in step S5 with phenyltriethoxysilane, then wash it thoroughly with hexane and dry it under vacuum at 70 °C to finally obtain a silicon-magnesium composite Ziegler-Natta catalyst support.
[0050] The properties of the porous silicon spheres obtained in step S4 are shown in Table 1, and the TEM image of the silicon-magnesium composite Ziegler-Natta catalyst support finally obtained in step S6 is as Figure 1c shown.
[0051] Table 1 Properties of the porous silicon spheres obtained in Examples 1-3
[0052] Calcination temperature / °C Calcination time / h Pore size / mesh Relative pore volume Relative pore diameter Example 1 600 4 100 1.16 1.29 Example 2 700 3 100 1.25 1.35 Example 3 550 5 100 1.37 1.37
[0053] As can be seen from Table 1, the porous silicon spheres prepared by the present invention as the carrier skeleton have a controllable pore structure and good mechanical strength. By Figures 1a to 1c it can be seen that the silicon-magnesium composite Ziegler-Natta catalyst support prepared by the present invention has uniform particle size and good sphericity.
[0054] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the technical principle of the present invention, several improvements and deformations can still be made, and these improvements and deformations should also be regarded as the protection scope of the present invention.
Claims
1. A method for preparing a silicon-magnesium composite Ziegler-Natta catalyst carrier, characterized in that: The preparation method comprises the following steps: S1. Preparation of silica sol: mixing a silicon source, a template, an acid catalyst and water, stirring evenly to obtain a silica sol; S2. Spray drying: spray drying the silicic acid sol obtained in step S1 to obtain a spherical silica gel carrier; S3. Aging: Aging the spherical silica gel carrier obtained in step S2 to further polycondense the spherical silica gel carrier; S4 Calcination: The spherical silica gel carrier obtained in step S3 is calcined in an air atmosphere to remove the template to obtain porous silicon spheres; S5. Loading a magnesium source: placing the porous silicon sphere obtained in step S4 in a single-necked flask, adding a soluble magnesium salt aqueous solution to the flask, stirring magnetically at room temperature, and using a rotary evaporator in a nitrogen stream to evaporate the water completely to obtain a porous silicon sphere loaded with a magnesium source; S6. Surface treatment: using an organic silane coupling agent to perform surface treatment on the porous silicon spheres loaded with a magnesium source obtained in step S5 to obtain a silicon-magnesium composite Ziegler-Natta catalyst carrier.
2. The method for preparing a silicon-magnesium composite Ziegler-Natta catalyst carrier according to claim 1, characterized in that: In step S1, the silicon source is one or more of tetraethyl orthosilicate, sodium silicate, and silica sol; the template is one or more of hexadecyltrimethylammonium bromide, polyethylene glycol, and block copolymer; and the acid catalyst is one or more of hydrochloric acid, perchloric acid, and sulfuric acid.
3. The method for preparing a silicon-magnesium composite Ziegler-Natta catalyst carrier according to claim 1, characterized in that: In step S1, the mass ratio of the silicon source, the template agent and the acid catalyst is 2:(1-4):(1-4).
4. The method for preparing a silicon-magnesium composite Ziegler-Natta catalyst carrier according to claim 1, characterized in that: In step S2, the inlet temperature of the spray drying is 150-250°C, and the outlet temperature is 80-120°C.
5. The method for preparing a silicon-magnesium composite Ziegler-Natta catalyst carrier according to claim 1, characterized in that: In step S3, the aging temperature is 40 to 80° C., and the aging time is 12 to 48 hours.
6. The method for preparing a silicon-magnesium composite Ziegler-Natta catalyst carrier according to claim 1, characterized in that: In step S4, the calcination temperature is 500-800° C., and the calcination time is 2-6 hours.
7. The method for preparing a silicon-magnesium composite Ziegler-Natta catalyst carrier according to claim 1, characterized in that: In step S5, the magnesium salt is one or more of magnesium acetate, magnesium citrate and magnesium chloride; the concentration of the magnesium salt aqueous solution is 0.25-1M, and n(Mg):n(Si)=5%-15%.
8. The method for preparing a silicon-magnesium composite Ziegler-Natta catalyst carrier according to claim 7, characterized in that: In step S5, the stirring time at room temperature is 4 to 8 hours, and the rotary evaporation heating temperature is 100°C.
9. The method for preparing a silicon-magnesium composite Ziegler-Natta catalyst carrier according to claim 1, characterized in that: In step S6, the organic silane coupling agent is one or more of methyltriethoxysilane, phenyltriethoxysilane, and vinyltriethoxysilane.
10. A silicon-magnesium composite Ziegler-Natta catalyst carrier, characterized in that: The silicon-magnesium composite Ziegler-Natta catalyst carrier is prepared by the method according to any one of claims 1 to 9.