Ziegler-Natta catalyst for olefin polymerization and preparation method thereof

Abstract

According to the Ziegler-Natta catalyst for olefin polymerization, a heteroatom-containing bicyclic succinic acid ester compound shown in the general formula (I) is adopted as an internal electron donor, and due to the unique coordination mode of the heteroatom-containing bicyclic succinic acid ester compound and a carrier and a special space electron structure, when the catalyst obtained after loading is used for catalyzing propylene polymerization, the catalyst has high catalytic activity; the product polypropylene can achieve higher stereoregularity, is wide in molecular weight distribution, and is expected to be developed into polymer products of various brands. The invention also discloses a preparation method of the supported catalyst. # imgabs0 #

Description

Technical Field

[0001] The invention belongs to the field of preparation of supported Ziegler-Natta catalysts for olefin polymerization, and in particular relates to a catalyst for propylene (co)polymerization and a preparation method thereof. Background Art

[0002] Supported Ziegler-Natta catalysts contain magnesium, titanium, halogens, and internal and external electron donors as basic components. They are particularly suitable for the polymerization of α-olefins with 3 or more carbon atoms, and the resulting olefin polymers have high yields and stereoregularity. Studies have shown that electron donors are one of the essential components of supported Ziegler-Natta catalysts, and polyolefin catalysts are constantly updated with the development of electron donor compounds.

[0003] At present, dibasic aromatic carboxylic acid ester compounds, such as di-n-butyl phthalate or diisobutyl phthalate, are more commonly used in industry (PMTrivedi, et al. J. Polym. Res., 2021, 28, Article number: 45). However, phthalates are typical plasticizers, and long-term use can cause harm to human health. Therefore, researchers have developed many non-phthalate electron donors for supported Ziegler-Natta catalysts. Typical are 1,3-diether compounds, such as 9,9-di(methoxymethyl)fluorene recently disclosed by CN1090194C, CN00103538 and CN1137155C. The Ziegler-Natta catalyst obtained after loading it has high catalytic activity and isotacticity for propylene polymerization. Researchers have recently tried to use other compounds as electron donors in olefin polymerization catalyst components, such as 1,8-naphthalene diphenol esters (WO2011084691A2 and US20110213106A1) reported by Chang et al. of BASF and 1,2-benzenediphenol esters (US20190338054A1 and CN102325808A) disclosed by Dow. The catalysts loaded with these electron donors have high activity and isotacticity. However, whether it is 1,3-diether or diol lipid compounds, the synthesis is difficult, and the molecular weight distribution of the polymer obtained by catalyzing olefin polymerization after the loaded catalyst is narrow, making the material difficult to process.

[0004] In order to solve this problem, Basell has developed a catalyst with succinate (butyric acid ester) as an electron donor, which not only has high stereospecific performance and catalytic activity, but also has a wide relative molecular mass distribution of polyolefins (CN1313869). For example, 2,3-diisopropyl succinate disclosed in patents such as WO2002030998 and polycyclic succinate electron donor compounds published by China National Petroleum Corporation (CN101831016A and CN101423571A). However, the synthesis of such compounds is complex and requires the use of low temperatures (such as -85°C, CN201310071720), which greatly limits the synthesis and industrial application of succinate compounds. Summary of the invention

[0005] The object of the present invention is to provide a catalyst for CH2=CHR olefin polymerization, wherein R is hydrogen or a hydrocarbon group having 1 to 12 carbon atoms. Another object of the present invention is to provide a preparation method containing the above catalyst.

[0006] The catalyst specifically includes:

[0007] (a) Main catalyst: in terms of weight percentage, comprising 10% to 25% magnesium, 1% to 10% titanium, 40% to 60% halogen and 1% to 30% internal electron donor, characterized in that the internal electron donor compound is selected from at least one succinate ester of the general formula (I):

[0008]

[0009] (b) an alkylaluminum compound;

[0010] (c) optionally, an external electron donor component;

[0011] Wherein, the group X is a heteroatom such as oxygen, sulfur or nitrogen, and the groups R1 and R2 are the same or different from each other and are C1 to C 20 a linear or branched alkyl, alkenyl, cycloalkyl, aryl, arylalkyl or alkylaryl group, optionally containing heteroatoms; the groups R3 to R8 are identical or different from each other and are hydrogen or C1-C 20 A linear or branched alkyl, alkenyl, cycloalkyl, aryl, arylalkyl or alkylaryl group, optionally containing heteroatoms, and two or more groups among R3 to R8 may be bonded to each other to form one or more condensed ring structures.

[0012] Calculated by the molar ratio of titanium:aluminum:external electron donor compound, the dosage ratio of each component in the catalyst is 1:5-1000:0-500.

[0013] Furthermore, in the above technical solution, in the above compound general formula (I), X is preferably an oxygen atom.

[0014] Furthermore, in the above technical solution, in the above compound general formula (I), R1 and R2 are preferably C1 to C 10 An alkyl group, a cycloalkyl group or an arylalkyl group, more preferably a C1-C 10 The alkyl group is preferably a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group or a neopentyl group, and particularly preferably an ethyl group, an isopropyl group, an n-butyl group or an isobutyl group.

[0015] Furthermore, in the above technical solution, in the above compound general formula (I), preferably at least one of the three groups of R3 and R4; R5 and R6; R7 and R8 is hydrogen, and more preferably both R3 and R4 are hydrogen.

[0016] Furthermore, in the above technical scheme, the above compound general formula (I) includes but is not limited to: 7-oxabicyclo [2.2.1] heptane-2,3-dicarboxylic acid dimethyl ester, 7-thiabicyclo [2.2.1] heptane-2,3-dicarboxylic acid diethyl ester, 7-methyl-7-amine-bicyclo [2.2.1] heptane-2,3-dicarboxylic acid di-n-butyl ester, 7-amine-bicyclo [2.2.1] heptane-2,3-dicarboxylic acid diisopropyl ester, 7-oxabicyclo [2.2.1] heptane-2,3-dicarboxylic acid di-n-butyl ester, 1-methyl-7-oxabicyclo [2.2.1] heptane-2,3 -diisobutyl dicarboxylate, dineopentyl 1-methyl-7-oxabicyclo[2.2.1]heptane-2,3-dicarboxylate, dineopentyl 1,4-dimethyl-7-oxabicyclo[2.2.1]heptane-2,3-dicarboxylate, diisobutyl 5,6-dimethyl-7-oxabicyclo[2.2.1]heptane-2,3-dicarboxylate, dineopentyl 1,2,3,4-tetramethyl-7-oxabicyclo[2.2.1]heptane-2,3-dicarboxylate or diisobutyl 1,4,5,6-tetramethyl-7-oxabicyclo[2.2.1]heptane-2,3-dicarboxylate.

[0017] Further, in the above technical scheme, the precursor of the above compound of general formula (I) can be obtained by esterification and Diels-Alder reaction, and finally by multiphase hydrogenation to obtain (I). The synthesis of the precursor of the compound of general formula (I) can be specifically referred to CN101824108A and CN101831016A. The definitions of substituents R1, R2, R5-R7 and X in the structural formula in the following synthetic route are the same as R1, R2, R5-R7 and X in formula (I).

[0018]

[0019] Furthermore, in the above technical solution, the particle size distribution of magnesium in the catalyst component is 20 to 250 μm, and the general formula is Mg(OR')mM (2-m) ·nROH is provided by a magnesium halide alcoholate, wherein R' is C1~C20 alkyl, aralkyl or aryl; M is halogen; m is an integer of 0≤m≤2; n is a decimal or integer of 0 < n < 6; R is C1-C 20 alkyl or aralkyl.

[0020] Mg(OR')mM(2 - m)+nROH → Mg(OR′) m M (2-m) ·nROH

[0021] The magnesium halide in the magnesium halide alcoholate is selected from one of magnesium dichloride, magnesium dibromide, chloromethoxymagnesium or chloroethoxymagnesium; the alcohol in the magnesium halide alcoholate is selected from one of methanol, ethanol, n-propanol, isopropanol, n-butanol or isobutanol, and ethanol is preferred.

[0022] Furthermore, in the above technical solution, the magnesium halide alcoholate is synthesized according to the literature report (US4399054). Taking the synthesis of the ethanol complex of magnesium chloride as an example, the specific synthesis method is as follows: At room temperature, 24 g of anhydrous MgCl2, 390 mL of vaseline oil, 50 mL of anhydrous ethanol, 10 mL of silicone oil and 2 mL of Span are added to a high-pressure reactor. Under nitrogen protection, it is stirred and heated to 130 °C for 3 hours to completely dissolve the solid. Then, nitrogen is continuously filled into the reactor and maintained at a pressure of 1 MPa. The discharge valve is opened, and the mixture in the reactor is passed through a thin tube with a diameter of 1.2 mm and a length of 3.54 m, and washed 5 times with hexane, and dried at room temperature to obtain a spherical carrier of the ethanol complex of MgCl2.

[0023] Titanium in the catalytic component is provided by a compound with the general formula TiA n (OR) 4-n , where R is a hydrocarbon group with 1 to 20 carbon atoms; A is halogen; n = 1 to 4. Specific compounds such as titanium tetrachloride, titanium tetrabromide, titanium tetraiodide, tetrabutoxytitanium, monochlorotriethoxytitanium, dichlorodiethoxytitanium or trichloroethoxytitanium are provided, and titanium tetrachloride is preferred.

[0024] The present invention provides a preparation method of the catalytic component a, including: ((1) adding spherical magnesium halide alcoholate particles to titanium halide liquid at -50 to 20 °C, reacting for 10 min to 5 h, and the molar ratio of magnesium to titanium is 1:5 to 1:100; (2) heating to 0 to 80 °C, adding an internal electron donor compound, and the molar ratio of magnesium to the internal electron donor compound is 2:1 to 20:1; (3) further heating to 100 to 150 °C and reacting for 1 to 6 h; (4) filtering and then adding the same titanium halide liquid as in step (1), reacting at 110 to 130 °C for 1 to 4 h, and then filtering, washing, and vacuum drying to obtain a supported catalyst.

[0025] The preferred preparation method is as follows: (1) adding spherical magnesium halide alcoholate particles to titanium halide liquid at -30 to 0°C, reacting for 1 to 5 hours, wherein the molar ratio of magnesium to titanium is 1:10 to 1:50; (2) heating to 30 to 60°C, adding an internal electron donor compound, wherein the molar ratio of magnesium to the internal electron donor compound is 2:1 to 12:1; (3) heating again to 110 to 130°C, reacting for 1 to 4 hours; (4) filtering, then adding the same titanium halide liquid as in step (1), reacting at 110 to 130°C for 1 to 2 hours, and then filtering, washing, and vacuum drying to obtain a supported catalyst.

[0026] In addition to the main catalyst, there are also alkyl aluminum compounds and external electron donor components;

[0027] The usage of each component is 1:5-1000:0-500 based on the molar ratio of titanium:aluminum:external electron donor compound.

[0028] Furthermore, in the above technical solution, the alkyl aluminum compound is a trialkyl aluminum compound, preferably a mixture of one or more of triethyl aluminum, triisobutyl aluminum, and tri-n-butyl aluminum.

[0029] Furthermore, in the above technical solution, the external electron donor can be selectively added as needed. For olefin polymers that need to have very high stereoregularity (such as an isotactic index greater than 99%), it is recommended to add an external electron donor compound.

[0030] Furthermore, in the above technical solution, the external electron donor can be selected to have the general formula R"' n Si(OR””) 4-n An organosilicon compound, wherein 0≤n≤3 is an integer; R'' and R"" are the same or different alkyl, cycloalkyl or aryl groups, optionally containing heteroatoms; R may also be a halogen or a hydrogen atom.

[0031] Furthermore, in the above technical solution, the organosilicon compound includes: trimethylmethoxysilane, trimethylethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, diphenyldimethoxysilane, diphenyldiethoxysilane, phenyltriethoxysilane, phenyltrimethoxysilane, vinyltrimethoxysilane, cyclohexylmethyldimethoxysilane, methyltert-butyldimethoxysilane, diisopropyldimethoxysilane, diisobutyldimethoxysilane, di-n-butyldimethoxysilane, dicyclopentyldimethoxysilane or di(cyclobutylmethyl)dimethoxysilane, preferably diphenyldimethoxysilane.

[0032] Furthermore, in the above technical solution, the usage ratio of each component in the catalyst is preferably 1:25-100:25-300, calculated on the molar ratio of titanium:aluminum:external electron donor compound.

[0033] The catalyst of the present invention can be used for olefin polymerization, especially homopolymerization of propylene or copolymerization of propylene with other olefins to obtain polymers with very high isotactic index. At the same time, it is not excluded that the catalyst is suitable for the production of polyethylene and copolymerization of ethylene with α-olefins such as propylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene or 1-octene.

[0034] When used for propylene polymerization, various methods in the prior art can be used, which can be carried out in liquid phase or gas phase, or in a combination of liquid phase and gas phase polymerization stages. The polymerization is usually carried out at 0 to 150°C, preferably 40 to 90°C. The polymerization pressure is 0.01 to 10 MPa. Hydrogen or other compounds that can act as chain transfer agents can be used to control the molecular weight of the polymer.

[0035] The present invention adopts a bicyclic succinate compound containing a special structure and a heteroatom as an internal electron donor. Its unique electronic effect makes the comprehensive performance of the catalyst excellent. When used for propylene (co)polymerization, a satisfactory polymerization yield can be obtained, and the stereospecificity of the polymer is high. At the same time, the catalyst is also very sensitive to hydrogen regulation. The molecular weight distribution of the obtained polymer is relatively wide, which is conducive to the development of different grades of polymers. DETAILED DESCRIPTION

[0036] The following embodiments are used to further illustrate the present invention, but not to limit the present invention.

[0037] 1. Synthesis of succinate compounds

[0038] The succinate of the present invention can be obtained by Diels-Alder reaction and heterogeneous catalytic hydrogenation. Di-n-butyl phthalate (99%) and di-n-butyl succinate (99%) were purchased from TCI (Shanghai).

[0039] Example 1 Synthesis of dineopentanol 1,4-dimethyl-7-oxabicyclo[2.2.1]heptane-2,3-dicarboxylate.

[0040] 24.0 g of 2,5-dimethylfuran and 31.8 g of dineopentyl butynedioate were added to a 150 mL flask, stirred and refluxed overnight, and separated by column chromatography to obtain 39.5 g of dineopentyl butynedioate, a colorless, transparent liquid product, with a yield of 90%. 1 H NMR (TMS, CDCl3, 400 MHz) analysis results: δ6.92 (s, 2H); δ4.07 (m, 4H); δ1.51 (s, 6H); δ1.06 (s, 18H).

[0041] 36.8 g of 1,4-dimethyl-7-oxabicyclo[2.2.1]hept-2,5-diene-2,3-dicarboxylic acid dineopentyl ester and 200 mg of commercial Pd / C catalyst were placed in a high-pressure reactor, the air in the reactor was replaced with hydrogen, and finally 1.0 MPa of hydrogen was injected. The reaction was carried out at 50° C. for 2 hours to obtain 37.2 g of oily colorless liquid 1,4-dimethyl-7-oxabicyclo[2.2.1]hept-2,3-dicarboxylic acid dineopentyl ester with a yield of 99%. 1 The H NMR results are shown in Table 1.

[0042] Example 2

[0043] Synthesis of dimethyl 7-oxabicyclo[2.2.1]heptane-2,3-dicarboxylate. The synthesis method is the same as in Example 1, except that 17.0 g of furan and 17.8 g of dimethyl butynedioate are used to replace 24.0 g of 2,5-dimethylfuran and 31.8 g of dineopentyl butynedioate. The total yield is 88%. 1 The H NMR results are shown in Table 1.

[0044] Example 3

[0045] Synthesis of diethyl 7-thiabicyclo[2.2.1]heptane-2,3-dicarboxylate. The synthesis method is the same as in Example 1, except that 21.0 g of thiophene and 21.3 g of diethyl butynedioate are used to replace 24.0 g of 2,5-dimethylfuran and 31.8 g of dineopentyl butynedioate. The total yield is 91%. 1 The H NMR results are shown in Table 1.

[0046] Example 4

[0047] Synthesis of 7-methyl-7-amine-bicyclo[2.2.1]heptyl-2,3-dicarboxylic acid di-n-butyl ester. The synthesis method is the same as that of Example 1, except that 20.3 g of N-methylpyrrole and 28.3 g of di-n-butyl butynedioate are used to replace 24.0 g of 2,5-dimethylfuran and 31.8 g of di-neopentyl butynedioate. The total yield is 85%. 1 The H NMR results are shown in Table 1.

[0048] Example 5

[0049] Synthesis of 7-methyl-7-amine-bicyclo[2.2.1]heptyl-2,3-dicarboxylic acid diisopropyl ester. The synthesis method is the same as that of Example 1, except that 20.3 g of N-methylpyrrole and 24.8 g of diisopropyl butynedioate are used to replace 24.0 g of 2,5-dimethylfuran and 31.8 g of dineopentyl butynedioate. The total yield is 95%. 1 The H NMR results are shown in Table 1.

[0050] Example 6

[0051] Synthesis of di-n-butyl 7-oxabicyclo[2.2.1]heptane-2,3-dicarboxylate. The synthesis method is the same as in Example 1, except that 17.0 g of furan and 28.3 g of di-n-butyl butynedioate are used to replace 24.0 g of 2,5-dimethylfuran and 31.8 g of di-neopentyl butynedioate. The total yield is 91%. 1 The H NMR results are shown in Table 1.

[0052] Example 7

[0053] Synthesis of 1-methyl-7-oxabicyclo[2.2.1]heptane-2,3-dicarboxylic acid diisobutyl ester. The synthesis method is the same as that of Example 1, except that 20.5 g of 2-methylfuran and 28.3 g of diisobutyl butynedioate are used to replace 24.0 g of 2,5-dimethylfuran and 31.8 g of dineopentyl butynedioate. The total yield is 90%. 1 The H NMR results are shown in Table 1.

[0054] Example 8

[0055] Synthesis of 1-methyl-7-oxabicyclo[2.2.1]heptyl-2,3-dicarboxylic acid dineopentyl alcohol ester. The synthesis method is the same as that of Example 1, except that 20.5 g of 2-methylfuran and 31.8 g of dineopentyl alcohol butynedioate are used instead of 24.0 g of 2,5-dimethylfuran and 31.8 g of dineopentyl alcohol butynedioate. The total yield is 90%. 1 The H NMR results are shown in Table 1.

[0056] Example 9

[0057] Synthesis of 5,6-dimethyl-7-oxabicyclo[2.2.1]heptane-2,3-dicarboxylic acid diisobutyl ester. The synthesis method is the same as that of Example 1, except that 24.0 g of 3,4-dimethylfuran and 28.3 g of diisobutyl butynedioate are used to replace 24.0 g of 2,5-dimethylfuran and 31.8 g of dineopentyl butynedioate. The total yield is 95%. 1 The H NMR results are shown in Table 1.

[0058] Example 10

[0059] Synthesis of 1,4,5,6-tetramethyl-7-oxabicyclo[2.2.1]heptane-2,3-dicarboxylic acid diisobutyl ester. The synthesis method is the same as that of Example 1, except that 31.0 g of 2,3,4,5-tetramethylfuran and 28.3 g of diisobutyl butynedioate are used to replace 24.0 g of 2,5-dimethylfuran and 31.8 g of dineopentyl butynedioate. The total yield is 91%. 1 The H NMR results are shown in Table 1.

[0060] Table 1. Internal electron donors 1HNMR results

[0061]

[0062] 2. Preparation of Catalytic Component A

[0063] TiCl4 was added to a dry glass reactor protected by nitrogen and cooled to -20°C. Microspherical magnesium chloride alcoholate (magnesium alcohol ratio of 2.9:1) carrier was added under stirring. The mixing ratio of carrier and TiCl4 was 1g:20mL. The reaction mixture was heated uniformly from -20°C to 0°C, and then to 70°C. The internal electron donor was added to the reactor, and the reaction mixture was heated to 110°C and continued to react for 2h; filtered, fresh equal amount of TiCl4 was added again, heated to 120°C and continued to react for 2h, filtered, washed the filter cake with hexane, and vacuum dried to obtain the catalyst component. The loading amount of the internal electron donor was determined by Angent 8890A gas chromatograph; the titanium loading amount was determined according to the spectrophotometer.

[0064] 3. Propylene polymerization

[0065] 0.2 mL of an external electron donor dicyclopentyldimethoxysilane, 8.0 mL of a hexane solution of a co-catalyst triethylaluminum with a concentration of 1 mol / L, and 0.01 mmol (calculated as titanium) of the catalyst component a prepared by the present invention were added to a 5 L autoclave in sequence, 2.5 L of liquid propylene and 0.2 MPa of hydrogen were introduced, stirred and mixed uniformly at room temperature, heated to 70° C., stirred for reaction for 2 h, the autoclave was opened to take out the polypropylene, and the polymer was weighed after cooling to room temperature and the propylene was completely volatilized, the activity of the catalyst was calculated, and the isotacticity, bulk density, melt index, particle size distribution, molecular weight distribution and other properties of the polypropylene were measured.

[0066] In Examples 11-20, propylene polymerization was carried out using the Ziegler-Natta catalyst synthesized by the internal electron donor in Examples 1-10 and the above-mentioned polymerization steps. The polymerization results are shown in Table 2.

[0067] Table 2. Aggregation results

[0068]

[0069] From the above results, it can be seen that the activity and isotacticity of the synthesized catalyst with succinate as internal electron donor are significantly better than those of the commercial di-n-butyl phthalate and di-n-butyl succinate supported catalysts.

Claims

1. A Ziegler-Natta catalyst for olefin polymerization, specifically comprising: (a) Main catalyst: in terms of weight percentage, comprising 10% to 25% magnesium, 1% to 10% titanium, 40% to 60% halogen and 1% to 30% internal electron donor, characterized in that the internal electron donor compound is selected from at least one succinate ester of the general formula (I): (b) an alkylaluminum compound; (c) optionally, an external electron donor component; Wherein the group X is an oxygen, sulfur or nitrogen heteroatom, the groups R1 and R2 are the same or different from each other and are selected from C1 to C 20 a linear or branched alkyl, alkenyl, cycloalkyl, aryl, arylalkyl or alkylaryl group, optionally containing heteroatoms; the groups R3, R4, R5, R6, R7, R8 are identical or different from each other and are selected from hydrogen or C1-C 20 a linear or branched alkyl, alkenyl, cycloalkyl, aryl, arylalkyl or alkylaryl group, optionally containing heteroatoms, and two or more groups among R3, R4, R5, R6, R7, R8 may be bonded to each other to form one or more condensed ring structures; Calculated by the molar ratio of titanium:aluminum:external electron donor compound, the dosage ratio of each component in the catalyst is 1:5-1000:0-500.

2. The main catalyst according to claim 1, characterized in that In the compound of general formula (I), R1 and R2 are ethyl, isopropyl, n-butyl, isobutyl or neopentyl.

3. The main catalyst according to claim 1, characterized in that In the compound of general formula (I), at least one of the three groups of R3 and R4; R5 and R6; R7 and R8 is hydrogen.

4. The main catalyst according to claim 1, characterized in that The internal electron donor compound of general formula (I) is dimethyl 7-oxabicyclo [2.2.1] heptane-2,3-dicarboxylate, diethyl 7-thiabicyclo [2.2.1] heptane-2,3-dicarboxylate, di-n-butyl 7-methyl-7-amine-bicyclo [2.2.1] heptane-2,3-dicarboxylate, diisopropyl 7-amine-bicyclo [2.2.1] heptane-2,3-dicarboxylate, di-n-butyl 7-oxabicyclo [2.2.1] heptane-2,3-dicarboxylate, diisobutyl 1-methyl-7-oxabicyclo [2.2.1] heptane-2,3-dicarboxylate , dineopentanol 1-methyl-7-oxabicyclo[2.2.1]heptane-2,3-dicarboxylate, dineopentanol 1,4-dimethyl-7-oxabicyclo[2.2.1]heptane-2,3-dicarboxylate, diisobutyl 5,6-dimethyl-7-oxabicyclo[2.2.1]heptane-2,3-dicarboxylate, dineopentanol 1,2,3,4-tetramethyl-7-oxabicyclo[2.2.1]heptane-2,3-dicarboxylate or diisobutyl 1,4,5,6-tetramethyl-7-oxabicyclo[2.2.1]heptane-2,3-dicarboxylate.

5. The main catalyst according to claim 1, characterized in that The particle size distribution of magnesium in the catalyst component is 20 to 250 μm, and the general formula is Mg(OR')mM (2-m) ·nROH is provided by a magnesium halide alcoholate, wherein R' is C1~C 20 alkyl, arylalkyl or aryl; M is halogen; m is an integer with 0 ≤ m ≤ 2; n is a decimal or an integer with 0 < n < 6; R is an alkyl or arylalkyl of C1~C 20 ; The titanium in the catalytic component is represented by the general formula TiA n (OR”) 4-n A compound is provided, wherein R" is a hydrocarbon group having 1 to 20 carbon atoms; A is a halogen; and n=1 to 4.

6. The main catalyst according to claim 5, characterized in that A magnesium halide alcoholate of magnesium is provided, wherein the magnesium halide is one of magnesium dichloride, magnesium dibromide, chloromethoxymagnesium or chloroethoxymagnesium; and the alcohol in the magnesium halide alcoholate is one of methanol, ethanol, n-propanol, isopropanol, n-butanol or isobutanol; The titanium in the catalytic component is provided by titanium tetrachloride, titanium tetrabromide, titanium tetraiodide, titanium tetrabutoxide, triethoxytitanium monochloride, diethoxytitanium dichloride or monoethoxytitanium trichloride.

7. A method for preparing the catalyst according to any one of claims 1 to 6, characterized in that The specific process of the main catalyst preparation method includes: (1) adding spherical magnesium halide alcohol compound particles to titanium halide liquid at -50 to 20°C, reacting for 10 minutes to 5 hours, and the molar ratio of magnesium to titanium is 1:5 to 1:100; (2) heating to 0 to 80°C, adding an internal electron donor compound, and the molar ratio of magnesium to the internal electron donor compound is 2:1 to 20:1; (3) heating to 100 to 150°C again, reacting for 1 to 6 hours; (4) after filtering, adding the same titanium halide liquid as step (1), reacting at 110 to 130°C for 1 to 4 hours, and then filtering, washing, and vacuum drying to obtain a supported catalyst.

8. The catalyst according to claim 7, characterized in that The main catalyst preparation process is as follows: (1) adding spherical magnesium halide alcohol compound particles to titanium halide liquid at -30 to 0°C, reacting for 1 to 5 hours, and the molar ratio of magnesium to titanium is 1:10 to 1:50; (2) heating to 30 to 60°C, adding an internal electron donor compound, and the molar ratio of magnesium to the internal electron donor compound is 2:1 to 12:1; (3) heating to 110 to 130°C, and reacting for 1 to 4 hours; (4) after filtering, adding the same titanium halide liquid as in step (1), reacting at 110 to 130°C for 1 to 2 hours, and then filtering, washing, and vacuum drying to obtain a supported catalyst.

9. The catalyst according to claim 1, characterized in that The alkyl aluminum compound is a trialkyl aluminum compound, preferably a mixture of one or more of triethyl aluminum, triisobutyl aluminum, and tri-n-butyl aluminum; The external electron donor is of the general formula R' n Si(OR””) 4-n An organosilicon compound, wherein 0≤n≤3 is an integer; R'' and R"" are the same or different alkyl, cycloalkyl or aryl groups.

10. The catalyst according to claim 9, characterized in that The external electron donor is diphenyldimethoxysilane.

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