Propylene polymerization spheroidal catalyst component, solid titanium procatalyst and preparation method and application thereof

Abstract

The application provides a propylene polymerization spherical catalyst component, a solid titanium main catalyst and a preparation method and application thereof. The solid titanium main catalyst comprises titanium halide, magnesium halide and peroxobenzoic acid ester internal electron donor. Under the action of an alkyl aluminum cocatalyst and an organic silicon compound external electron donor, the catalyst is used for propylene polymerization or copolymerization, shows very high polymerization activity, very good hydrogen regulation sensitivity and stereospecificity, can manufacture green and environment-friendly propylene polymers with high isotacticity, good particle morphology and few fine powders, and can be used for producing high melt index polypropylene products.

Description

Technical Field

[0001] This invention belongs to the field of catalyst technology, and relates to a solid Ziegler-Natta catalyst for propylene polymerization or copolymerization, its preparation method, and its application in catalytic propylene polymerization or copolymerization reactions. Specifically, it relates to a catalyst component and catalyst using a magnesium compound as a support and an electron donor with a specific chemical structure. Background Technology

[0002] Polypropylene (PP) materials possess characteristics such as low relative density, good mechanical properties, good molding and processing performance, high heat resistance, good chemical properties, and pure, non-toxic texture. Polymer microparticles made from PP have important applications in fiber products, medical devices, automobiles, bicycles, parts, pipelines, chemical containers, food packaging, and pharmaceutical packaging. The catalyst used in propylene polymerization is crucial to the performance of PP materials.

[0003] Since the discovery and application of Ziegler-Natta catalysts in the industrial production of polypropylene, over sixty years of research and development have led to the evolution of polypropylene catalysts from the first to the fifth generation, from the initial low-activity complex catalysts to the current high-activity, spherical or near-spherical catalysts. In the development of propylene polymerization catalysts, the continuous use of new electron-donating compounds has driven their upgrading, endowing propylene polymerization catalysts with higher activity and better stereoregulation, resulting in polypropylene materials with better performance. Therefore, it can be said that electron-donating compounds are the core of polypropylene catalysts. Initially, researchers added ethyl benzoate or phthalate esters as internal electron donors in the preparation of Ziegler-Natta catalysts, forming solid titanium catalysts. During olefin polymerization, another electron donor (alkoxysilane compound) was added, resulting in highly isotactic polypropylene, demonstrating that the addition of electron-donating compounds significantly improved the stereoregulation of the catalyst. Subsequently, research on internal and external electron donors has become a core technology in the development of Ziegler-Natta catalysts for propylene polymerization. Currently, a series of aliphatic dicarboxylic acid esters have been reported in China as electron donors for Ziegler-Natta catalysts in propylene polymerization. Among them, succinate esters exhibit the best performance, resulting in polymers with a wide molecular weight distribution. Catalysts using succinate esters as internal electron donors possess high stereoregulation properties; their most significant characteristic is that the resulting polypropylene has a wide relative molecular weight distribution, improving the processing performance of polypropylene. Products previously only achievable through multi-reactor processes can be produced using single-reactor polymerization, and the products are high-rigidity homopolymers and multiphase copolymers, expanding the performance of propylene homopolymers and copolymers. Some patents also report the use of diol esters as electron donors for Ziegler-Natta catalysts in propylene polymerization, characterized by a wide molecular weight distribution, high catalytic activity, easily tunable stereoregulation properties, and high isotacticity and a wide relative molecular weight distribution of polypropylene even without the addition of external electron donors. Some patents also report on catalysts prepared by combining magnesium halides, titanium compounds, and organic diethers or polyethers, such as using 1,3-diether as an electron donor compound. This catalyst system can produce highly isotactic polypropylene without the need for the addition of an external electron donor during polymerization and has high activity.

[0004] The use of the aforementioned electron-donating compounds endows solid titanium catalysts with good catalytic performance, but also has certain drawbacks. For example, phthalate electron donors can cause certain harm to human health and the environment, while succinate, diol esters, and diether electron donors face challenges in synthesis, including long synthetic routes and high production costs. Therefore, it is necessary to continue research on electron-donating compounds for Ziegler-Natta catalysts in propylene polymerization. Summary of the Invention

[0005] In view of the above-mentioned technical problems and defects, the purpose of this invention is to provide a spherical catalyst component for propylene polymerization. The internal electron donor in this component is an industrially available benzoyl peroxide compound, which can overcome the problems of difficult synthesis and high production cost of the aforementioned electron donors. In addition, the catalyst prepared by using benzoyl peroxide compound as an internal electron donor exhibits high catalytic activity, high stereotacticity, good hydrogen regulation sensitivity, copolymerization performance, and sensitivity to reaction temperature when catalyzing olefin polymerization. After being used in propylene polymerization, it can produce green and environmentally friendly propylene polymers with high polymer isotacticity, good particle morphology, high apparent density, and less fine powder, and can be used to produce polypropylene products with high melt index.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A spherical catalyst component for propylene polymerization includes a solid titanium main catalyst, an alkyl aluminum compound co-catalyst, and / or an external electron donor compound; wherein the solid titanium main catalyst includes any one or a mixture of two or more of magnesium, magnesium halide, alkyl magnesium, or alkoxy magnesium, a liquid titanium compound, and an internal electron donor compound;

[0008] The internal electron donor compound is selected from one or more compounds having the structure of formula (I):

[0009]

[0010] In the formula, R is selected from H atoms, halogens, C1 to C2 atoms. 20 Linear or branched alkyl, alkenyl, cycloalkyl, aryl, arylalkyl or alkylaryl groups.

[0011] As a preferred embodiment of the present invention, the alkylaluminum compound co-catalyst has the general formula AlR. 1 n X 3－n In the formula R 1 Are they the same or different C1~C? 20 Alkyl groups, including straight-chain, branched or cyclic alkyl groups, where X is a halogen and n = 1, 2 or 3;

[0012] The external electron donor compound is of the general formula R. n Si(OR ’ ) 4-n Organosilicon compounds, where 0 ≤ n ≤ 3, R and R ’ R can be the same or different alkyl, cycloalkyl, aryl, or haloalkyl groups; or R can be a halogen or a hydrogen atom.

[0013] As a preferred embodiment of the present invention, the ratio between the solid titanium main catalyst, the alkyl aluminum compound co-catalyst, and the external electron donor compound is such that, based on the molar ratio of titanium, the amount of the alkyl aluminum compound co-catalyst is 5 to 1000 moles; and based on the molar ratio of aluminum, the amount of the external electron donor compound is 0.025 to 1.0 moles.

[0014] As a preferred embodiment of the present invention, the magnesium is micron-sized spherical magnesium particles; the magnesium halide is selected from magnesium dihalides, complexes of magnesium dihalides with water or alcohol, and derivatives of magnesium dihalides in which one halogen atom is replaced by a hydrocarbon group or hydrocarbon oxygen group; the alkyl magnesium includes diethyl magnesium, di-n-butyl magnesium, and di-n-hexyl magnesium, and the alkoxy magnesium includes ethoxy magnesium.

[0015] Preferably, the liquid titanium compound is a liquid compound that is completely soluble in a nonpolar solvent at the application temperature, and the general formula of the liquid titanium compound is Ti(OR). 4－a X a In the general formula, R represents C1 to C2. 10 The hydrocarbon group, X is selected from F, Cl, Br, a is an integer from 1 to 4, and its amount is 0.5 to 150 moles per mole of magnesium halide.

[0016] As a further preferred embodiment of the present invention, the alkylaluminum compound cocatalyst is selected from any one or a mixture of two or more of triethylaluminum, triisobutylaluminum, tri-n-butylaluminum, tri-n-hexylaluminum, and alkylaluminum chloride.

[0017] As a further preferred embodiment of the present invention, the magnesium halide is selected from any one or a mixture of two or more of magnesium dichloride, magnesium dibromide, magnesium phenoxychloride, magnesium isopropoxychloride, and magnesium butoxychloride, preferably magnesium dichloride.

[0018] As a further preferred embodiment of the present invention, the liquid titanium compound is selected from one or a mixture of two or more of titanium tetrachloride, titanium tetrabromide, titanium tetraiodide, titanium tetrabutoxy, titanium tetraethoxy, titanium monochlorotriethoxy, titanium dichlorodiethoxy, and titanium trichloromonoethoxy, preferably titanium tetrachloride.

[0019] As a further preferred embodiment of the present invention, the internal electron donor compound is selected from any one or a mixture of two or more of benzoic acid peroxide, methyl benzoate peroxide, ethyl benzoate peroxide, isopropyl benzoate peroxide, tert-butyl benzoate peroxide, tert-hexyl benzoate peroxide, and tert-amyl benzoate peroxide; the amount of the internal electron donor compound, calculated per mole of magnesium halide, is 0.10 to 0.50 moles.

[0020] This invention also provides a solid titanium master catalyst for propylene polymerization or copolymerization, comprising any one or a mixture of two or more of magnesium, magnesium halide, alkyl magnesium, or alkoxy magnesium, a liquid titanium compound, and an internal electron donor compound; wherein the internal electron donor compound is selected from one or more compounds having the structure of formula (I):

[0021]

[0022] In the formula, R is selected from H atoms, halogens, C1 to C2 atoms. 20 Linear or branched alkyl, alkenyl, cycloalkyl, aryl, arylalkyl or alkylaryl groups.

[0023] As a preferred embodiment of the present invention, the magnesium is micron-sized spherical magnesium particles; the magnesium halide is selected from magnesium dihalides, complexes of magnesium dihalides with water or alcohol, and derivatives of magnesium dihalides in which one halogen atom is replaced by a hydrocarbon group or hydrocarbon oxygen group; the alkyl magnesium includes diethyl magnesium, di-n-butyl magnesium, and di-n-hexyl magnesium, and the alkoxy magnesium includes ethoxy magnesium.

[0024] The liquid titanium compound should be a liquid compound that is completely soluble in nonpolar solvents at the application temperature, and the general formula of the liquid titanium compound is Ti(OR). 4－a X a In the general formula, R represents C1 to C2. 10 The hydrocarbon group, X is selected from F, Cl, Br, and a is an integer from 1 to 4.

[0025] As a preferred embodiment of the present invention, the solid titanium main catalyst further includes alkyl aluminum compounds, including trimethylaluminum, triethylaluminum, triisobutylaluminum, diethylaluminum chloride, and other alkyl aluminum compounds.

[0026] This invention also provides a method for preparing a solid titanium main catalyst for propylene polymerization or copolymerization, the method comprising the following steps:

[0027] Step 1. Dissolve any one or a mixture of two or more of magnesium, magnesium halide, alkyl magnesium, or alkoxy magnesium in a solvent system containing organic alcohol to form a homogeneous solution;

[0028] Step 2. Add liquid titanium compound. The contact reaction temperature between the liquid titanium compound and the magnesium halide solution is controlled at -40 to 0°C to ensure that the active titanium / magnesium components are a homogeneous solution. The amount of titanium compound added is 1 to 50 mol per mole of magnesium halide, preferably 4 to 40 mol.

[0029] Step 3. Heat the mixture from Step 2, add an internal electron donor compound to adjust the catalyst activity, hydrogen sensitivity, and polymer regularity, then add or omit the alkylaluminum compound, continue heating, and stir to precipitate solid titanium main catalyst particles. The resulting solid titanium main catalyst should have a titanium content between 0.5% and 4.0%, a magnesium content between 5.0% and 20.0%, an internal electron donor compound content between 5.0% and 15.0%, and a specific surface area of ​​100–500 m². 2 The pore volume is between 0.5 and 1.5 mL / g;

[0030] or,

[0031] Step 1. Dissolve any one or a mixture of two or more of magnesium, magnesium halide, alkyl magnesium, or alkoxy magnesium in a solvent system containing an organic alcohol to form a homogeneous solution; then add an internal electron donor compound to the homogeneous solution to adjust the activity of the catalyst, hydrogen sensitivity, and polymer regularity.

[0032] Step 2. Add liquid titanium compound. The contact reaction temperature between the liquid titanium compound and the magnesium halide solution is controlled at -40 to 0°C to ensure that the active titanium / magnesium components are a homogeneous solution. The amount of titanium compound added is 1 to 50 mol per mole of magnesium halide, preferably 4 to 40 mol.

[0033] Step 3. Heat the mixture from Step 2, adding or not adding alkylaluminum compounds, then continue heating and stirring to precipitate solid titanium main catalyst particles. The resulting solid titanium main catalyst should contain titanium at a content of 0.5–4.0%, magnesium at a content of 5.0–20.0%, and internal electron donor compounds at a content of 5.0–15.0%, with a specific surface area of ​​100–500 m². 2 The pore volume is between 0.5 and 1.5 mL / g.

[0034] As a preferred embodiment of the present invention, the organic alcohol is a straight-chain or branched alkyl alcohol, cycloalkanol, or aromatic alcohol or arylalkanol with 1 to 10 carbon atoms, and halogenated derivatives of the above organic alcohols, including methanol, ethanol, propanol, isopropanol, butanol, pentanol, hexanol, 2-methylpentanol, 2-ethylbutanol, heptanol, 2-ethylhexanol, octanol, and decanol; the organic alcohol is used alone or in combination, wherein the amount of organic alcohol compound used is 0.1 to 10.0 mol per mole of magnesium halide.

[0035] As a preferred embodiment of the present invention, one or more inert diluents may be optionally added to the solvent system described in step 1. The inert diluents include hexane, heptane, octane, decane, benzene, toluene, xylene, 1,2-dichloroethane, chlorobenzene, and other hydrocarbons or halogenated hydrocarbons. Any substance that helps dissolve magnesium halide can be used. The dissolution temperature is controlled between 10 and 150°C. Dissolution can also be carried out under certain temperature and pressure conditions. The dissolution time is based on complete dissolution.

[0036] In the preparation of the solid titanium main catalyst, solid catalyst particles precipitate during the heating process of the reaction system. The heating rate can be fast or slow to adjust the particle size of the catalyst, and the temperature should be controlled below the boiling point of the solvent. The internal electron donor compound can be added during the heating process of the reaction between the liquid titanium compound and the magnesium halide solution, or it can be added to the organic alcohol solution of magnesium halide. It can be added at once or in batches.

[0037] The resulting catalyst particles can be processed through conventional washing and drying steps to obtain a fluidized solid powder catalyst. Furthermore, to adjust the titanium content in the catalyst, the catalyst particles can be washed once or multiple times.

[0038] The spherical catalyst component for propylene polymerization or the solid titanium main catalyst for propylene polymerization or copolymerization provided by this invention can be used in the polymerization reaction of olefins CH2=CHR, where R is hydrogen or an alkyl or aryl group with 1 to 6 carbons. When using the above-mentioned catalyst component or solid titanium main catalyst for olefin polymerization, it can be carried out according to known methods, including liquid-phase bulk polymerization, solution polymerization of liquid monomers dissolved in an inert solvent, gas-phase polymerization, or a combination of liquid-phase bulk polymerization and gas-phase polymerization, or gas-phase polymerization and gas-phase polymerization. The propylene polymerization temperature is generally 0℃ to 150℃, preferably 60℃ to 100℃, and the polymerization reaction pressure is atmospheric pressure or high pressure.

[0039] Advantages and beneficial effects of the present invention:

[0040] (1) The solid titanium main catalyst provided by the present invention adopts an internal electron donor compound with a specific structure, which makes the obtained catalyst have high polymerization activity and stereotactic orientation ability; at the same time, it maintains the characteristics of narrow particle size distribution, good hydrogen sensitivity, large pore volume and large pore size, and can be used for olefin polymerization, and is suitable for slurry polymerization, bulk polymerization, bulk-gas phase combination and gas phase polymerization processes.

[0041] (2) When the solid titanium main catalyst provided by the present invention is used as a catalyst component in combination with alkyl aluminum compound co-catalyst and external electron donor compound, it is highly sensitive to the reaction temperature and can be used to produce polypropylene with high melt index. At the same time, it can also make the molecular weight distribution of the obtained polypropylene product wider, effectively improving the processing performance of polypropylene products.

[0042] (3) The internal electron donor provided by the present invention is an industrially available benzoyl peroxide compound, which can overcome the problems of difficult synthesis and high production cost of existing internal electron donors.

[0043] (4) In the preparation process of the solid titanium main catalyst, the present invention adds alkyl aluminum compounds to Ti 4+ Pre-reduction is performed to form Ti 3+ It has the advantages of easy coordination with magnesium halides, which can improve the activity of the main catalyst and improve the polymerization kinetics of the main catalyst; the resulting polymer products have the characteristics of narrow molecular weight distribution and high melt index.

[0044] (5) The catalyst components provided by the present invention can be used to manufacture propylene polymers that are green and environmentally friendly, have high polymer isotacticity, good particle morphology, high apparent density, and few fine powders. Detailed Implementation

[0045] To more clearly illustrate the present invention, the following description, in conjunction with preferred embodiments, further clarifies the invention. Those skilled in the art should understand that the specific descriptions below are illustrative rather than restrictive, and should not be construed as limiting the scope of protection of the present invention.

[0046] Example 1

[0047] 1. Synthesis of solid titanium main catalyst:

[0048] (1) In a glass bottle that has been fully replaced with high-purity N2, 7.14 g (75 mmol) of anhydrous magnesium chloride, 37.5 mL of decane and 35.1 mL (225 mmol) of 2-ethylhexanol were added in sequence. The suspension was heated at 130 °C for 3 hours to obtain a homogeneous solution.

[0049] (2) Add the magnesium chloride alcohol solution from step (1) dropwise to 200 mL (1.8 mol) of titanium tetrachloride solution at a temperature maintained at -24 °C.

[0050] (3) Heat the mixture from step (2) to 40°C within a certain time, add 2.0 ml (7.5 mmol) of benzoic acid peroxide to the mixture, and then raise the temperature to 110°C. After the temperature reaches 110°C, stir the mixture at the same temperature for 2 hours.

[0051] (4) The solid obtained by hot filtration was resuspended in 200 mL of titanium tetrachloride, then heated to 110 °C, stirred for 30 min, and filtered. The solid was first thoroughly washed with decane at 110 °C, and then washed with hexane at 60 °C until no titanium compounds were detected in the washing liquid. After drying, a solid titanium catalyst was obtained.

[0052] The analytical results of the solid titanium main catalyst are as follows: Ti, 2.3%; Mg, 17.1%; electron donor, 12.8%.

[0053] 2. Propylene Polymerization: After fully purging the 2-liter stainless steel polymerization reactor with high-purity N2, 12.1 mg of the above-mentioned solid titanium main catalyst, 2.0 mmol of triethylaluminum, and 0.1 mmol of methylcyclohexyldimethoxysilane (CHMDMS) were added, along with 1.0 L (standard volume) of hydrogen gas. Liquid propylene was then added to a final volume of 1.0 L. The temperature was raised to 70 °C, and the polymerization reaction was carried out for 1 hour. The catalyst analysis results are shown in Table 1, and the polymerization results are shown in Tables 2 and 3.

[0054] Example 2

[0055] 1. Synthesis of solid titanium main catalyst:

[0056] Except for replacing benzoic acid with methyl benzoate, the rest is the same as in Example 1.

[0057] The analytical results of the solid titanium main catalyst are as follows: Ti, 2.4%; Mg, 16.9%; electron donor, 11.4%.

[0058] 2. Polymerization: Same as in Example 1. Catalyst analysis results are shown in Table 1, and polymerization results are shown in Tables 2 and 3.

[0059] Example 3

[0060] 1. Synthesis of solid titanium main catalyst:

[0061] Except for replacing benzoic acid with ethyl benzoate peroxide, the rest is the same as in Example 1.

[0062] The analytical results of the solid titanium main catalyst are as follows: Ti, 2.1%; Mg, 18.4%; electron donor, 13.3%.

[0063] 2. Polymerization: Same as in Example 1. Catalyst analysis results are shown in Table 1, and polymerization results are shown in Tables 2 and 3.

[0064] Example 4

[0065] 1. Synthesis of solid titanium main catalyst:

[0066] Except for replacing benzoic acid with isopropyl benzoate peroxide, the rest is the same as in Example 1.

[0067] The analytical results of the solid titanium main catalyst are as follows: Ti, 2.7%; Mg, 18.3%; electron donor, 12.6%.

[0068] 2. Polymerization: Same as in Example 1. Catalyst analysis results are shown in Table 1, and polymerization results are shown in Tables 2 and 3.

[0069] Example 5

[0070] 1. Catalyst Synthesis:

[0071] Except for replacing benzoic acid with tert-butyl peroxide, the rest is the same as in Example 1.

[0072] The analytical results of the solid titanium main catalyst are as follows: Ti, 2.5%; Mg, 18.2%; electron donor, 12.8%.

[0073] 2. Polymerization: Same as in Example 1. Catalyst analysis results are shown in Table 1, and polymerization results are shown in Tables 2 and 3.

[0074] Example 6

[0075] 1. Synthesis of solid titanium main catalyst:

[0076] Except for replacing benzoic acid with tert-amyl peroxide, the rest is the same as in Example 1.

[0077] The analytical results of the solid titanium main catalyst are as follows: Ti, 2.4%; Mg, 18.6%; electron donor, 12.5%.

[0078] 2. Polymerization: Same as in Example 1. Catalyst analysis results are shown in Table 1, and polymerization results are shown in Tables 2 and 3.

[0079] Example 7

[0080] 1. Synthesis of solid titanium main catalyst:

[0081] (1) In a glass bottle that has been fully replaced with high-purity N2, 7.14 g (75 mmol) of anhydrous magnesium chloride, 37.5 mL of decane and 35.1 mL (225 mmol) of 2-ethylhexanol were added in sequence. The suspension was heated at 130 °C for 3 hours to obtain a homogeneous solution. 2.0 mL (7.5 mmol) of isopropyl benzoate peroxide was added to the homogeneous solution and kept at 130 °C for 1 hour.

[0082] (2) Add the magnesium chloride alcohol solution from step (1) dropwise to 200 mL (1.8 mol) of titanium tetrachloride solution at a temperature maintained at -24 °C.

[0083] (3) After heating the mixture from step (2) to 110°C within a certain time, stir it at a constant temperature for 2 hours.

[0084] (4) The solid obtained by hot filtration was resuspended in 200 mL of titanium tetrachloride, then heated to 110 °C, stirred for 30 min, and filtered. The solid was first thoroughly washed with decane at 110 °C, and then washed with hexane at 60 °C until no titanium compounds were detected in the washing liquid. After drying, a solid titanium catalyst was obtained.

[0085] The analytical results of the solid titanium main catalyst are as follows: Ti, 2.2%; Mg, 15.9%; electron donor, 13.3%.

[0086] 2. Propylene Polymerization: After fully purging a 2-liter stainless steel polymerization reactor with high-purity N2, 12.3 mg of the above-mentioned solid catalyst, 2.0 mmol of triethylaluminum, and 0.1 mmol of methylcyclohexyldimethoxysilane (CHMDMS) were added, along with 1 L (standard volume) of hydrogen gas. Liquid propylene was then added to a final volume of 1.0 L. The temperature was raised to 70 °C, and polymerization was carried out for 1 hour. The catalyst analysis results are shown in Table 1, and the polymerization results are shown in Tables 2 and 3.

[0087] Example 8

[0088] 1. Synthesis of solid titanium main catalyst:

[0089] Except for the amount of benzoic acid peroxide, which was 3.0 mL (11.25 mmol), everything else was the same as in Example 1.

[0090] The analytical results of the solid titanium main catalyst are as follows: Ti, 2.9%; Mg, 17.4%; electron donor, 12.8%.

[0091] 2. Polymerization: Same as in Example 1. Catalyst analysis results are shown in Table 1, and polymerization results are shown in Tables 2 and 3.

[0092] Example 9

[0093] 1. Synthesis of solid titanium main catalyst:

[0094] (1) In a glass bottle that has been fully replaced with high-purity N2, 7.14 g (75 mmol) of anhydrous magnesium chloride, 0.5 g of spherical magnesium powder, 37.5 mL of decane and 35.1 mL (225 mmol) of 2-ethylhexanol were added in sequence. The suspension was heated at 130 °C for 3 hours to obtain a homogeneous solution.

[0095] (2) Add the magnesium chloride alcohol solution from step (1) dropwise to 200 mL (1.8 mol) of titanium tetrachloride solution at a temperature maintained at -24 °C.

[0096] (3) Heat the mixture from step (2) to 40°C within a certain time, add 2.0 ml (7.5 mmol) of isopropyl benzoate peroxide to the mixture, and then raise the temperature to 110°C; after the temperature reaches 110°C, stir the mixture at the same temperature for 2 hours.

[0097] (4) The solid obtained by hot filtration was resuspended in 200 mL of titanium tetrachloride, then heated to 110 °C, stirred for 30 min, and filtered. The solid was first thoroughly washed with decane at 110 °C, and then washed with hexane at 60 °C until no titanium compounds were detected in the washing liquid. After drying, a solid titanium catalyst was obtained.

[0098] The analytical results of the solid titanium main catalyst are as follows: Ti, 2.6%; Mg, 16.6%; electron donor, 12.8%.

[0099] 2. Propylene Polymerization: After fully purging a 2-liter stainless steel polymerization reactor with high-purity N2, 12.3 mg of the above-mentioned solid catalyst, 2.0 mmol of triethylaluminum, and 0.1 mmol of methylcyclohexyldimethoxysilane (CHMDMS) were added, along with 1 L (standard volume) of hydrogen gas. Liquid propylene was then added to a final volume of 1.0 L. The temperature was raised to 70 °C, and the polymerization reaction was carried out for 1 hour. The catalyst analysis results are shown in Table 1, and the polymerization results are shown in Tables 2 and 3.

[0100] Example 10

[0101] 1. Synthesis of solid titanium main catalyst:

[0102] (1) In a glass bottle that has been fully replaced with high-purity N2, 7.14 g (75 mmol) of anhydrous magnesium chloride, 37.5 mL of decane and 35.1 mL (225 mmol) of 2-ethylhexanol were added in sequence. The suspension was heated at 130 °C for 3 hours to obtain a homogeneous solution.

[0103] (2) Add the magnesium chloride alcohol solution from step (1) dropwise to 200 mL (1.8 mol) of titanium tetrachloride solution at a temperature maintained at -24 °C.

[0104] (3) Heat the mixture from step (2) to 40°C within a certain time period, add 2.0 mL (7.5 mmol) of isopropyl benzoate peroxide to the mixture, then add 5.0 mL (1.0 mmol / mL) of decane solution of triethylaluminum dropwise to the mixture, and then raise the temperature to 110°C; after the temperature reaches 110°C, stir the mixture at the same temperature for 2 hours.

[0105] (4) The solid obtained by hot filtration was resuspended in 200 mL of titanium tetrachloride, then heated to 110 °C, stirred for 30 min, and filtered. The solid was first thoroughly washed with decane at 110 °C, and then washed with hexane at 60 °C until no titanium compounds were detected in the washing liquid. After drying, a solid titanium catalyst was obtained.

[0106] The analytical results of the solid titanium main catalyst are as follows: Ti, 3.0%; Mg, 16.6%; electron donor, 12.5%.

[0107] 2. Propylene Polymerization: After fully purging a 2-liter stainless steel polymerization reactor with high-purity N2, 12.3 mg of the above-mentioned solid catalyst, 2.0 mmol of triethylaluminum, and 0.1 mmol of methylcyclohexyldimethoxysilane (CHMDMS) were added, along with 1 L (standard volume) of hydrogen gas. Liquid propylene was then added to a final volume of 1.0 L. The temperature was raised to 70 °C, and the polymerization reaction was carried out for 1 hour. The catalyst analysis results are shown in Table 1, and the polymerization results are shown in Tables 2 and 3.

[0108] Comparative Example 1

[0109] 1. Catalyst Synthesis:

[0110] Except for replacing benzoic acid peroxide with diisobutyl phthalate, the rest is the same as in Example 1.

[0111] The analytical results of the solid titanium main catalyst are as follows: Ti, 3.2%; Mg, 17.1%; electron donor, 10.9%.

[0112] 2. Propylene polymerization: Same as in Example 1. Catalyst analysis results are shown in Table 1, and polymerization results are shown in Tables 2 and 3.

[0113] Table 1. Particle size distribution and diameter of the catalyst

[0114]

[0115] Table 2 Polymerization results of the catalyst

[0116]

[0117] Table 3. Sieving results of polymer powder

[0118]

[0119] Based on the data obtained from the above examples and comparative examples, it can be determined that the solid titanium main catalyst obtained using the internal electron donor provided by the present invention has the characteristics of good particle morphology, narrow particle size distribution, good hydrogen regulation sensitivity, and less fine polymer powder. The internal electron donor compound of the present invention has a specific peroxide structure and carbonyl and ester groups in its structure. The carbonyl and ester groups can coordinate with MgCl2, thereby strengthening the interaction between the internal electron donor and MgCl2. The peroxide-OO- structure is formed by two oxygen atoms connected by nonpolar covalent bonds, forming an ionic group. These two oxygen atoms share a pair of electrons, and each oxygen atom presents a 7-electron structure. Each oxygen atom needs to gain one electron to achieve a stable 8-electron structure. In particular, when an oxygen molecule accepts an electron, a super-active ionic structure is formed. This structural feature promotes the coordination reaction activity of carbonyl, ester, MgCl2, and TiCl4, making its coordination effect stronger. It is not easily removed by alkyl aluminum during polymerization, thereby improving the stereotactic ability of the solid titanium catalyst and making the obtained polypropylene product have a wider molecular weight distribution and a higher melt index.

[0120] In the Ziegler-Natta catalyst system for propylene polymerization, the main role of the co-catalyst alkylaluminum is to reduce tetravalent titanium to trivalent titanium, which is the active center of the propylene polymerization catalyst. This invention adds a certain amount of alkylaluminum compound to the solid titanium main catalyst during its preparation to enhance the activity of Ti… 4+ Pre-reduction is performed to form Ti 3+ It has the advantages of easy coordination with magnesium halides and dispersion in the main catalyst, which can improve the activity of the main catalyst and improve the polymerization reaction kinetics of the main catalyst. The resulting polymer products have the characteristics of narrow molecular weight distribution and high melt index.

[0121] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. For those skilled in the art, other variations or modifications can be made based on the above description. It is impossible to exhaustively list all the implementation methods here. All obvious variations or modifications derived from the technical solutions of the present invention are still within the protection scope of the present invention.

Claims

1. A spherical catalyst component for propylene polymerization, comprising a solid titanium main catalyst, an alkylaluminum compound co-catalyst, and an external electron donor compound; characterized in that, The solid titanium main catalyst includes any one or a mixture of two or more of magnesium, magnesium halide, alkyl magnesium, or alkoxy magnesium, liquid titanium compounds, and internal electron donor compounds. The internal electron donor compound is selected from one or more compounds having the structure of formula (I): In the formula, R is selected from H atoms, halogens, C1 to C2 atoms. 20 Linear or branched alkyl, alkenyl, cycloalkyl, aryl, arylalkyl or alkylaryl groups.

2. The spherical catalyst component for propylene polymerization according to claim 1, characterized in that, The alkylaluminum compound cocatalyst has the general formula AlR. 1 n X 3－n In the formula R 1 Are they the same or different C1~C? 20 Alkyl groups, including straight-chain, branched or cyclic alkyl groups, where X is a halogen and n = 1, 2 or 3; The external electron donor compound is of the general formula R. n Si(OR ’ ) 4-n Organosilicon compounds, where 0 ≤ n ≤ 3, R and R ’ R can be the same or different alkyl, cycloalkyl, aryl, or haloalkyl groups; or R can be a halogen or a hydrogen atom.

3. The spherical catalyst component for propylene polymerization according to claim 1, characterized in that, The ratio between the solid titanium main catalyst, the alkyl aluminum compound co-catalyst, and the external electron donor compound is as follows: the amount of alkyl aluminum compound co-catalyst is 5 to 1000 moles based on the molar ratio of titanium; and the amount of external electron donor compound is 0.025 to 1.0 moles based on the molar ratio of aluminum.

4. The spherical catalyst component for propylene polymerization according to claim 1, characterized in that, The magnesium is micron-sized spherical magnesium particles; the magnesium halide is selected from magnesium dihalides, complexes of magnesium dihalides with water or alcohol, and derivatives of magnesium dihalides in which one halogen atom is replaced by a hydrocarbon group or hydrocarbon oxygen group; the alkyl magnesium includes diethyl magnesium, di-n-butyl magnesium, and di-n-hexyl magnesium, and the alkoxy magnesium includes ethoxy magnesium. The liquid titanium compound should be a liquid compound that is completely soluble in nonpolar solvents at the application temperature, and the general formula of the liquid titanium compound is Ti(OR). 4－a X a In the general formula, R represents C1 to C2. 10 The hydrocarbon group, X is selected from F, Cl, Br, a is an integer from 1 to 4, and its amount is 0.5 to 150 moles per mole of magnesium halide.

5. The spherical catalyst component for propylene polymerization according to claim 2, characterized in that, The alkylaluminum compound cocatalyst is selected from any one or a mixture of two or more of triethylaluminum, triisobutylaluminum, tri-n-butylaluminum, tri-n-hexylaluminum, and alkylaluminum chloride.

6. The spherical catalyst component for propylene polymerization according to claim 4, characterized in that, The magnesium halide is selected from any one or a mixture of two or more of magnesium dichloride, magnesium dibromide, magnesium phenoxychloride, magnesium isopropoxychloride, and magnesium butoxychloride. The liquid titanium compound is selected from any one or a mixture of two or more of titanium tetrachloride, titanium tetrabromide, titanium tetraiodide, titanium tetrabutoxy, titanium tetraethoxy, titanium monochlorotriethoxy, titanium dichlorodiethoxy, and titanium trichloromonoethoxy. The internal electron donor compound is selected from any one or a mixture of two or more of benzoic acid peroxide, methyl benzoate peroxide, ethyl benzoate peroxide, isopropyl benzoate peroxide, tert-butyl benzoate peroxide, tert-hexyl benzoate peroxide, and tert-amyl benzoate peroxide; the amount of the internal electron donor compound is 0.10 to 0.50 mol per mole of magnesium halide.

7. A solid titanium main catalyst for propylene polymerization or copolymerization, characterized in that, The mixture includes any one or more of magnesium, magnesium halide, alkyl magnesium, or alkoxy magnesium, liquid titanium compounds, and internal electron donor compounds; wherein the internal electron donor compound is selected from one or more compounds having the structure of formula (I): In the formula, R is selected from H atoms, halogens, C1 to C2 atoms. 20 Linear or branched alkyl, alkenyl, cycloalkyl, aryl, arylalkyl or alkylaryl groups.

8. A solid titanium main catalyst for propylene polymerization or copolymerization according to claim 7, characterized in that, The solid titanium main catalyst also includes alkyl aluminum compounds, including trimethylaluminum, triethylaluminum, triisobutylaluminum, and diethylaluminum chloride.

9. The method for preparing the solid titanium main catalyst according to claim 7 or 8, characterized in that, The method includes the following steps: Step 1. Dissolve any one or a mixture of two or more of magnesium, magnesium halide, alkyl magnesium, or alkoxy magnesium in a solvent system containing organic alcohol to form a homogeneous solution; Step 2. Add liquid titanium compound. The contact reaction temperature between the liquid titanium compound and the magnesium halide solution is controlled at -40 to 0℃ to ensure that the active titanium / magnesium components are a homogeneous solution. The amount of titanium compound added is 1 to 50 mol per mole of magnesium halide. Step 3. Heat the mixture from Step 2, add an internal electron donor compound to adjust the catalyst activity, hydrogen sensitivity, and polymer regularity, and then add or not add an alkylaluminum compound, continue heating, and stir to precipitate solid titanium main catalyst particles, so that the titanium content in the obtained solid titanium main catalyst is between 0.5% and 4.0%; the magnesium content is between 5.0% and 20.0%; and the content of the internal electron donor compound is between 5.0% and 15.0%. or, Step 1. Dissolve any one or a mixture of two or more of magnesium, magnesium halide, alkyl magnesium, or alkoxy magnesium in a solvent system containing an organic alcohol to form a homogeneous solution; then add an internal electron donor compound to the homogeneous solution to adjust the activity of the catalyst, hydrogen sensitivity, and polymer regularity. Step 2. Add liquid titanium compound. The contact reaction temperature between the liquid titanium compound and the magnesium halide solution is controlled at -40 to 0℃ to ensure that the active titanium / magnesium components are a homogeneous solution. The amount of titanium compound added is 1 to 50 mol per mole of magnesium halide. Step 3. Heat the mixture from Step 2, with or without adding alkylaluminum compounds, and then continue heating and stirring to precipitate solid titanium main catalyst particles, so that the titanium content in the obtained solid titanium main catalyst is between 0.5% and 4.0%; the magnesium content is between 5.0% and 20.0%; and the content of internal electron donor compounds is between 5.0% and 15.0%.

10. The application of the spherical catalyst component for propylene polymerization according to any one of claims 1 to 6 or the solid titanium main catalyst for propylene polymerization or copolymerization according to claims 7 or 8 in the olefin CH2=CHR polymerization reaction, wherein R is hydrogen or an alkyl or aryl group with 1 to 6 carbons.

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