Olefin polymerization catalyst

Abstract

The present invention discloses an olefin polymerization catalyst, the olefin polymerization catalyst comprises a catalyst component, an organic aluminum compound, an external electron donor and an activity regulator, and the activity regulator is pepper acid ester represented by a formula I, r1 is selected from straight chain or branched chain alkyl of C1-C20 and derivatives thereof, naphthenic base of C3-C20, aryl of C6-C20 and derivatives thereof, aralkyl of C7-C20 and derivatives thereof, alkylene of C2-C10, fused ring aryl of C10-C20 and ester of C10-C20. According to the present invention, the pepper acid ester is adopted as the activity regulator component, and the component is matched with the olefin polymerization catalyst of a variety of internal electron donors, such that the high activity and the high directionality of the catalyst can be maintained while the temperature fluctuation of the high activity catalyst during the operation in the device can be reduced.

Description

Technical Field

[0001] This invention relates to a catalyst for olefin polymerization, belonging to the field of polyolefin catalysts. Background Technology

[0002] Catalysts are a core technology and a major driving force for the development of the polypropylene industry. They are central to the advancement of polypropylene technology, largely determining the microstructure, mechanical properties, and processing performance of the product. Ziegler-Natta polypropylene catalysts will continue to evolve towards serialization and high performance based on high activity and high directionality, continuously developing new products with better performance. Advances in catalyst technology are crucial for improving polypropylene performance and reducing production costs, making catalyst development a focus of attention. Highly active polyolefin catalysts possess excellent comprehensive performance and can be applied to various polymerization processes to produce multiple grades of polyolefin products. Their high activity is particularly suitable for the production of clean polypropylene products such as electrical membrane polypropylene and medical polypropylene. Furthermore, highly active catalysts can have their catalytic performance indicators adjusted through modifications to the internal electron donor structure, component blending, catalyst preparation processes, and polymerization processes to meet the development requirements of other high-end olefin products, such as low-dissolution PP, medical-grade PP, high-crystallinity, high-rigidity, low-VOC automotive-grade PP, and high-melt-strength PP—key products for quality improvement or addressing shortcomings—showing broad application prospects.

[0003] Industrial polymerization equipment typically uses a relatively fixed program to control the reaction temperature. When using highly active catalysts with significantly higher activity than conventional catalysts, large temperature fluctuations often occur, affecting safe production and product quality. Adjusting monomer concentration and reducing catalyst dosage can lower the reaction temperature, but this also results in large temperature fluctuations. Adding suitable activity modifiers during polymerization can regulate the chain transfer rate and the concentration and activity of active centers, thus regulating the polymerization reaction rate within a certain range and achieving the goal of controlling polymerization temperature fluctuations. Summary of the Invention

[0004] In the production process of polyolefin plants, low catalyst activity increases production costs, increases product ash content, affects product quality, and reduces the competitiveness of polyolefin products. Therefore, it is necessary to improve catalyst activity to meet production requirements. However, when highly active catalysts operate in polyolefin plants, the polymerization temperature often fluctuates greatly due to uneven active centers, excessively high initial reaction rates, and large activity fluctuations, affecting stable production and product quality. The purpose of this invention is to provide a catalyst containing an activity regulator that, while maintaining the performance advantages of highly active catalysts, reduces temperature fluctuations that occur when highly active catalysts operate in the plant.

[0005] To achieve the above objectives, the present invention provides an olefin polymerization catalyst comprising: a catalyst component, an organoaluminum compound, an external electron donor, and an activity modifier, wherein the activity modifier is a piperic ester as shown in Formula I.

[0006]

[0007] Among them, R 1 Selected from C1-C 20 Straight-chain or branched alkyl groups and their derivatives, C3-C 20 cycloalkyl, C6-C 20 aryl groups and their derivatives, C7-C 20 Araneyl groups and their derivatives, C2-C 10 olefin group, C 10 -C 20 Fused ring aryl, C 10 -C 20 The ester group.

[0008] According to a specific embodiment of the present invention, preferably, R 1 It also contains heteroatoms, which include one or more combinations of N, O, S, P, and Si.

[0009] According to a specific embodiment of the present invention, preferably, in formula I, R 1 Selected from methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, isopentyl, cyclopentyl, n-hexyl, cyclohexyl, heptyl, octyl, nonyl, decyl, C 11 -C 20 Straight-chain or branched alkyl groups, and the following substituents with 20 or fewer carbon atoms: alkenyl, phenyl, m-chlorophenyl, p-chlorophenyl, o-chlorophenyl, m-methoxyphenyl, p-methoxyphenyl, o-methoxyphenyl, p-methylphenyl, p-nitrophenyl, m-nitrophenyl, benzyl and its derivatives, phenethyl and its derivatives, furanyl, pyrroleyl, thiophenyl, indene.

[0010] According to a specific embodiment of the present invention, preferably, the piperate ester includes one or more of the following: methyl piperate, ethyl piperate, n-propyl piperate, isopropyl piperate, n-butyl piperate, isobutyl piperate, n-pentyl piperate, isopentyl piperate, n-octyl piperate, isooctyl piperate, cyclohexyl piperate, and phenyl piperate.

[0011] The piperic ester can be prepared by esterification of piperic acid with the corresponding alcohol, and the esterification process is as follows:

[0012]

[0013] According to a specific embodiment of the present invention, preferably, the catalyst component comprises Mg, Ti, and halogen; preferably, the catalyst component further comprises an internal electron donor compound selected from Lewis bases.

[0014] The Lewis base is preferably selected from one or more of ethers, esters, ketones and amines.

[0015] The Lewis base compound is further preferably selected from at least one of the following compounds: 2,6-dicarboxylate-4-pyranone, 2,6-dimethoxy-substituted-4-pyranone, 2,6-dimethoxycarbonyl-substituted-4-pyranone, 2,6-dicarboxylate-4-pyridinyl ether, N-substituted-2,6-dicarboxylate-4-pyridinyl ether, chloramphenicol ester, kojic acid ester, ascorbic acid ester, quercetin ester / ether, aromatic monoester, aromatic diester, aliphatic diester, and 1,3-diether.

[0016] According to a specific embodiment of the present invention, preferably, the catalyst component comprises a titanium compound, a magnesium compound, and an internal electron donor; the precursor of the magnesium compound is selected from X. n Mg(OR a ) 2-n MgCl2·mR a OH, R a 2-n MgX n One or more combinations of MgCl2 / SiO2, MgCl2 / Al2O3, magnesium halides, and titanium alkoxides, wherein m is 0.1-6, 0≤n≤2, X is a halogen, and R a For C1-C 20 The hydrocarbon group; the general formula of the titanium compound is TiX. N (OR b ) 4-N , where R b For C1-C 20 The hydrocarbon group, where X is a halogen and N is 1-4.

[0017] According to a specific embodiment of the present invention, preferably, the magnesium compound is an alkoxide of magnesium dihalide; or, the magnesium compound is a liquid magnesium compound (a magnesium compound dissolved in a liquid); or, the magnesium compound is a derivative in which at least one halogen atom in a magnesium dihalide molecule is replaced by an alkyl group or a haloalkyl group; preferably, it is an alkyloxy magnesium compound; more preferably, it is an alkoxy magnesium and / or an aryloxy magnesium.

[0018] According to a specific embodiment of the present invention, preferably, the titanium compound includes one or a combination of two or more of titanium tetrachloride, titanium tetrabromide, titanium tetraiodide, and titanium alkoxyhalides.

[0019] According to a specific embodiment of the present invention, preferably, the alkyl titanium halide includes one or a combination of two or more of methoxy titanium trichloride, ethoxy titanium trichloride, propoxy titanium trichloride, n-butoxy titanium trichloride, dimethoxy titanium dichloride, diethoxy titanium dichloride, dipropoxy titanium dichloride, di-n-butoxy titanium dichloride, trimethoxy titanium chloride, triethoxy titanium chloride, tripropoxy titanium chloride, and tri-n-butoxy titanium chloride.

[0020] According to a specific embodiment of the present invention, preferably, the titanium compound is titanium tetrachloride.

[0021] According to a specific embodiment of the present invention, preferably, the molar ratio of the internal electron donor to the magnesium compound calculated as magnesium element is 0.01-5.0, more preferably 0.05-3.0.

[0022] According to a specific embodiment of the present invention, preferably, the organoaluminum compound has the general formula AlR c p X (3-p) , where R c It is hydrogen or C1-C 20 The hydrocarbon group, X is a halogen, and p is an integer 0 ≤ p ≤ 3.

[0023] According to a specific embodiment of the present invention, preferably, the organoaluminum compound includes one or more of the following: trialkylaluminum compound, alkylaluminum halide, alkylaluminum hydride, alkylaluminum sesquichloride, and alkylaluminoxane.

[0024] According to a specific embodiment of the present invention, preferably, the trialkylaluminum compound includes one or more of trimethylaluminum, triethylaluminum, triisobutylaluminum, tri-n-butylaluminum, tri-n-hexylaluminum, and trioctylaluminum; the alkylaluminum halide includes AlEt2Cl; the alkylaluminum sesquichloride includes Al2Et3Cl3; more preferably, the organoaluminum compound is a mixture of AlEt2Cl and Al2Et3Cl3.

[0025] According to a specific embodiment of the present invention, preferably, the molar ratio of the organoaluminum compound to the titanium atoms in the catalyst component is 1-1000:1, more preferably 50-800.

[0026] According to a specific embodiment of the present invention, preferably, the external electron donor is a siloxane compound.

[0027] According to a specific embodiment of the present invention, preferably, the general formula of the siloxane compound is R'. t Si(OR”) 4-t In this context, R' and R” are each independently selected from C1-C 18The hydrocarbon group, where t is an integer 0 ≤ t ≤ 3.

[0028] According to a specific embodiment of the present invention, preferably, R' and R” each contain heteroatoms.

[0029] According to a specific embodiment of the present invention, preferably, the heteroatom includes one or more combinations of N, O, S, P, and Si.

[0030] According to a specific embodiment of the present invention, preferably, the siloxane compound includes trimethylmethoxysilane, trimethylethoxysilane, tri-n-propylmethoxysilane, tri-n-propylethoxysilane, tri-n-butylmethoxysilane, triisobutylethoxysilane, tricyclohexylmethoxysilane, tricyclohexylethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, di-n-propyldimethoxysilane, diisopropyldimethoxysilane, di-n-propyldiethoxysilane, diisopropyldiethoxysilane, di-n-butyldiethoxysilane, diisobutyldiethoxysilane, di-tert-butyldimethoxysilane, di-tert-butyldimethoxysilane, di-n-butyldimethoxysilane, diisobutyldimethoxysilane, di-tert-butyldiethoxysilane. Di-n-butyldiethoxysilane, n-butylmethyldimethoxysilane, di(2-ethylhexyl)dimethoxysilane, di(2-ethylhexyl)diethoxysilane, dicyclohexyldimethoxysilane, dicyclohexyldiethoxysilane, dicyclopentyldimethoxysilane, dicyclopentyldiethoxysilane, cyclohexylmethyldimethoxysilane, cyclohexylmethyldiethoxysilane, cyclohexylethyldimethoxysilane, cyclohexylisopropyldimethoxysilane, cyclohexylethyldiethoxysilane, cyclopentylmethyldimethoxysilane, cyclopentylmethyldiethoxysilane, cyclopentylethyldimethoxysilane, cyclopentylethyldiethoxysilane, cyclopentylisopropyldiethoxysilane, cyclopentylisobutyldimethoxysilane, cyclohexyl-n-propyldimethoxysilane Cyclohexyl-n-propyldiethoxysilane, cyclohexyl-n-butyldiethoxysilane, pentylmethyldimethoxysilane, diphenyldimethoxysilane, pentylmethyldiethoxysilane, pentylethyldimethoxysilane, pentylethyldiethoxysilane, cyclohexyldimethylmethoxysilane, cyclohexyldiethylmethoxysilane, cyclohexyldiethylmethoxysilane, cyclohexyldiethylethoxysilane, 2-ethylhexyltrimethoxysilane, cyclohexyldimethoxysilane, cyclohexyldiethoxysilane, 2-ethylhexyltriethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, n-propyltrimethoxysilane, n-propyltriethoxysilane, isopropyltrimethoxysilane, isopropyltriethoxysilane, n-butyltrimethoxysilane, isobutyl Trimethoxysilane, tert-butyltrimethoxysilane, n-butyltriethoxysilane, cyclohexyltrimethoxysilane, cyclohexyltriethoxysilane, cyclopentyltrimethoxysilane, cyclopentyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, 2-ethylhexyltrimethoxysilane, 2-ethylhexyltriethoxysilane, pentyltrimethoxysilane, pentyltriethoxysilane, phenyltriethoxysilane, tetramethoxysilane, tetraethoxysilane, cyclohexylcyclopentyldimethoxysilane, cyclohexylcyclopentyldiethoxysilane, cyclohexylcyclopentyldipropoxysilane, 3-methylcyclohexylcyclopentyldimethoxysilane, 4-methylcyclohexylcyclopentyldimethoxysilane, 3,5-dimethylcyclopentyldimethoxysilane, 3,The following are included in the list of one or more of the following: 5-dimethylcyclohexylcyclopentyldimethoxysilane, 3-methylcyclohexylcyclohexyldimethoxysilane, di(3-methylcyclohexyl)dimethoxysilane, 4-methylcyclohexylcyclohexyldimethoxysilane, di(4-methylcyclohexyl)dimethoxysilane, 3,5-dimethylcyclohexylcyclohexyldimethoxysilane, di(3,5-dimethylcyclohexyl)dimethoxysilane, tetrapropoxysilane, tetrabutoxysilane, methyl tert-butyldimethoxysilane, 2-ethylpiperidinyl-2-tert-butyldimethoxysilane, (1,1,1-trifluoro-2-propyl)-2-ethylpiperidinyldimethoxysilane, and (1,1,1-trifluoro-2-propyl)-methylmethoxysilane.

[0031] According to a specific embodiment of the present invention, preferably, the siloxane compound includes di-n-propyl dimethoxysilane, diisopropyl dimethoxysilane, di-n-butyl dimethoxysilane, diisobutyl dimethoxysilane, di-tert-butyl dimethoxysilane, di-n-butyl diethoxysilane, tert-butyl trimethoxysilane, dicyclohexyl dimethoxysilane, dicyclohexyl diethoxysilane, cyclohexylmethyl dimethoxysilane, and cyclohexylethyl diethoxysilane. One or more combinations of cyclohexylethyldimethoxysilane, cyclohexylethyldiethoxysilane, cyclopentylmethyldimethoxysilane, cyclopentylmethyldiethoxysilane, cyclopentylethyldimethoxysilane, cyclohexylcyclopentyldimethoxysilane, cyclohexylcyclopentyldiethoxysilane, 3-methylcyclohexylcyclopentyldimethoxysilane, 4-methylcyclohexylcyclopentyldimethoxysilane, and 3,5-dimethylcyclopentyldimethoxysilane.

[0032] According to a specific embodiment of the present invention, preferably, the siloxane compound includes one or more combinations of cyclohexylmethyldimethoxysilane, diisopropyldimethoxysilane, di-n-butyldimethoxysilane, diisobutyldimethoxysilane, diphenyldimethoxysilane, phenyltriethoxysilane, methyl tert-butyldimethoxysilane, dicyclopentyldimethoxysilane, 2-ethylpiperidinyl-2-tert-butyldimethoxysilane, (1,1,1-trifluoro-2-propyl)-2-ethylpiperidinyldimethoxysilane, (1,1,1-trifluoro-2-propyl)-methyldimethoxysilane, cyclohexyltrimethoxysilane, tert-butyltrimethoxysilane, and tert-hexyltrimethoxysilane.

[0033] According to a specific embodiment of the present invention, preferably, the molar ratio of silicon in the external electron donor to titanium in the catalyst component is 0.002-100, more preferably 0.01-20, and even more preferably 0.01-5.

[0034] According to a specific embodiment of the present invention, preferably, the molar ratio of the piperidine ester to the external electron donor is (0.02-50):1, more preferably (0.1-10):1.

[0035] The present invention also provides an application of the above-mentioned catalyst in olefin polymerization.

[0036] According to a specific embodiment of the present invention, preferably, the olefin comprises a straight-chain or branched olefin, more preferably one or a combination of two or more of ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, 3-methyl-1-butene, 4-methyl-1-pentene, butadiene, vinylcyclopentene, and vinylcyclohexene.

[0037] According to a specific embodiment of the present invention, preferably, the polymerization includes ethylene and / or propylene polymerization.

[0038] According to a specific embodiment of the present invention, preferably, the polymerization includes homopolymerization or copolymerization.

[0039] According to a specific embodiment of the present invention, preferably, during the catalytic process, the order of adding the components in the catalyst is arbitrary, with the organoaluminum compound being added to the polymerization system first, followed by the external electron donor and the activity regulator, and finally the catalyst components.

[0040] According to a specific embodiment of the present invention, preferably, the polymerization can be carried out with or without a solvent; the olefin can be in the gas phase or the liquid phase; more preferably, hydrogen can be further added as a molecular weight regulator (polymerization can also be carried out without a molecular weight regulator); the polymerization is a continuous polymerization or a batch polymerization, and the polymerization can be carried out in one step, two steps or multiple steps.

[0041] According to a specific embodiment of the present invention, preferably, the polymerization temperature is ≤200℃, more preferably 20-100℃, and even more preferably 40-80℃; the polymerization pressure is ≤10MPa, more preferably 0.3-5MPa.

[0042] This invention provides a piper ester activity modifier component that is compatible with a variety of internal electron donor olefin polymerization catalysts. It can reduce temperature fluctuations that occur when highly active catalysts are running in the device while maintaining the high activity and high orientation of the catalyst. Detailed Implementation

[0043] In order to provide a clearer understanding of the technical features, objectives and beneficial effects of the present invention, the technical solution of the present invention will now be described in detail below, but it should not be construed as limiting the scope of implementation of the present invention.

[0044] The isotacticity of polymers was determined by the heptane extraction method (boiling heptane extraction for 6 hours): two grams of dry polymer sample were placed in an extractor and extracted with boiling heptane for 6 hours. The residue was then dried to constant weight. The ratio of the obtained polymer weight (g) to 2 is the isotacticity.

[0045] Preparation of catalyst components

[0046] The preparation methods of the catalyst components in Examples 1-8 are as follows:

[0047] In a 500 mL stirred flask equipped with a stirrer and fully purged with nitrogen, 10 g of MgCl2·2.5C2H5OH microspheres and 150 mL of titanium tetrachloride were added to prepare a suspension. The suspension was then maintained at -10 °C for 1 hour, and slowly heated to 90 °C. 10 mmol of internal electron-donating compounds a1-a8 were added, and the temperature was further increased to 110 °C and held constant for 1 hour. The liquid was then filtered off, and the resulting solid was washed three times with 120 mL of titanium tetrachloride at 125 °C. It was then washed four times with 150 mL of hexane at 60 °C. Finally, the liquid was filtered off and dried to obtain the solid catalyst components C1-C8.

[0048] Examples 1-8

[0049] The polymerization was carried out using catalyst components C1-C8 as components of the olefin polymerization catalyst:

[0050] After purging the 5L stainless steel reactor with nitrogen, 5 mL of a 0.5 mol / L triethylaluminum hexane solution, 1 mL of a 0.1 mol / L cyclohexylmethyldimethoxysilane hexane solution, the amount of activity modifier b1 (0.1 mol / L hexane solution) as described in Table 1, and 10 mg of the prepared catalyst component were added. Then, 10 mL of hexane was added to flush the feed line, followed by 2 L (under standard conditions) of hydrogen and 2.5 L of purified propylene. The reaction was prepolymerized at 25°C for 5 minutes, then the temperature was raised to 70°C, and polymerization was carried out at this temperature for 1 hour. After the reaction, the reactor was cooled and stirring was stopped. The reaction product was discharged and dried to obtain the polymer. Polymerization data are shown in Table 1.

[0051] Examples 9-16

[0052] Example 1 of the polysynthetic formulation differs in that the amount of activity modifier b2 (0.1 mol / L hexane solution) described in Table 1 is added.

[0053] Examples 17-24

[0054] Example 1 of the polysynthetic formulation differs in that the amount of activity modifier b3 (0.1 mol / L hexane solution) described in Table 1 is added.

[0055] Examples 25-32

[0056] Example 1 of the polysynthetic formulation differs in that the amount of activity modifier b4 (0.1 mol / L hexane solution) described in Table 1 is added.

[0057] Comparative Examples 1-8:

[0058] The polymerization evaluation was conducted using C1-C8 catalyst components as the components of the olefin polymerization catalyst.

[0059] After purging the 5L stainless steel reactor with nitrogen, 5mL of a 0.5mol / L triethylaluminum hexane solution, 1mL of a 0.1mol / L cyclohexylmethyldimethoxysilane hexane solution, and 10mg each of the prepared catalyst components C1-C8 were added. Then, 10mL of hexane was added to flush the feed line, followed by 2L (under standard conditions) of hydrogen and 2.5L of purified propylene. The reaction was prepolymerized at 25℃ for 5 minutes, then the temperature was raised to 70℃, and polymerization was carried out at this temperature for 1 hour. After the reaction, the reactor was cooled and stirring was stopped. The reaction product was discharged and dried to obtain the polymer. Polymerization data are shown in Table 1.

[0060] Table 1

[0061]

[0062]

[0063]

[0064] Internal electron donor a:

[0065] a1, di-n-butyl phthalate;

[0066] a2,9,9-dimethoxymethylfluorene;

[0067] a3,2,6-Dibutyl di-n-butyl 4-pyranone;

[0068] a4,2,6-Dimethoxymethyl-4-pyranone;

[0069] a5, di-n-butyl 2,6-dicarboxylate-4-methoxypyridine; a6, N-isopropyl-2,6-diethyl-4-pyridone; a7, chlorobenzyl butyl ester;

[0070] a8, tetrabutyl ascorbate.

[0071] Activity regulator b:

[0072] b1, isopropyl piperate;

[0073] b2, n-Amyl piperate;

[0074] b3, isooctyl piperate;

[0075] b4, phenyl piperine.

[0076] As can be seen from Table 1, in Comparative Examples 1-8, the temperature fluctuation in the reactor was within ±2 to ±3℃ when no activity regulator was added during polymerization. After adding piperitate, the temperature fluctuation was significantly reduced, and the resulting polypropylene still maintained a high level of isotacticity. The catalytic activity of catalysts containing different internal electron donors was only slightly reduced, but most of them were still higher than the activity of Comparative Example 1 (the activity level of the most commonly used catalyst system in industry), and were more suitable for meeting the requirements of stable operation of industrial plants.

[0077] Of course, the present invention may have other various embodiments. Without departing from the spirit and essence of the present invention, those skilled in the art can make various corresponding changes and modifications according to the present invention, but these corresponding changes and modifications should all fall within the protection scope of the present invention.

Claims

1. An olefin polymerization catalyst, characterized in that, It comprises: a catalyst component, an organoaluminum compound, an external electron donor, and an activity modifier, wherein the activity modifier is a piperic acid ester of Formula I: Among them, R 1 Selected from C1-C 20 Straight-chain or branched alkyl groups and their derivatives, C3-C 20 cycloalkyl, C6-C 20 aryl groups and their derivatives, C7-C 20 Araneyl groups and their derivatives, C2-C 10 olefin group, C 10 -C 20 Fused ring aryl, C 10 -C 20 The ester group.

2. The olefin polymerization catalyst according to claim 1, characterized in that, R 1 It also contains heteroatoms, which include one or more combinations of N, O, S, P, and Si.

3. The olefin polymerization catalyst according to claim 1, characterized in that, In formula I, R 1 Selected from methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, isopentyl, cyclopentyl, n-hexyl, cyclohexyl, heptyl, octyl, nonyl, decyl, C 11 -C 20 Straight-chain or branched alkyl groups, and the following substituents with 20 or fewer carbon atoms: alkenyl, phenyl, m-chlorophenyl, p-chlorophenyl, o-chlorophenyl, m-methoxyphenyl, p-methoxyphenyl, o-methoxyphenyl, p-methylphenyl, p-nitrophenyl, m-nitrophenyl, benzyl and its derivatives, phenethyl and its derivatives, furanyl, pyrroleyl, thiophenyl, indene.

4. The olefin polymerization catalyst according to claim 1, characterized in that, The piperate esters include one or more of the following: methyl piperate, ethyl piperate, n-propyl piperate, isopropyl piperate, n-butyl piperate, isobutyl piperate, n-pentyl piperate, isopentyl piperate, n-octyl piperate, isooctyl piperate, cyclohexyl piperate, and phenyl piperate.

5. The olefin polymerization catalyst according to claim 1, characterized in that, The catalyst components include: Mg, Ti, and halogens; Preferably, the catalyst component further contains an internal electron donor compound selected from Lewis bases; More preferably, the Lewis base is selected from one or more of ethers, esters, ketones and amines; More preferably, the Lewis base compound is selected from at least one of the following compounds: 2,6-dicarboxylate-4-pyranone, 2,6-dimethoxy-substituted-4-pyranone, 2,6-dimethoxycarbonyl-substituted-4-pyranone, 2,6-dicarboxylate-4-pyridinyl ether, N-substituted-2,6-dicarboxylate-4-pyridinyl ether, chloramphenicol ester, kojic acid ester, ascorbic acid ester, quercetin ester / ether, aromatic monoester, aromatic diester, aliphatic diester, and 1,3-diether.

6. The olefin polymerization catalyst according to claim 1, characterized in that, The catalyst component comprises titanium compounds, magnesium compounds, and internal electron donors; Preferably, the precursor of the magnesium compound is selected from X. n Mg(OR a ) 2-n MgCl2·mR a OH, R a 2-n MgX n One or more combinations of MgCl2 / SiO2, MgCl2 / Al2O3, magnesium halides, and titanium alkoxides, wherein m is 0.1-6, 0≤n≤2, X is a halogen, and R a For C1-C 20 hydrocarbon group; More preferably, the magnesium compound is an alkoxide of magnesium dihalide; or, the magnesium compound is a liquid magnesium compound; or, the magnesium compound is a derivative in which at least one halogen atom in a magnesium dihalide molecule is replaced by an alkyl group or a haloalkyl group; preferably, it is an alkyloxy magnesium compound; more preferably, it is an alkoxy magnesium and / or an aryloxy magnesium. Preferably, the titanium compound has the general formula TiX. N (OR b ) 4-N , where R b For C1-C 20 The hydrocarbon group, where X is a halogen and N is 1-4; More preferably, the titanium compound includes one or more of titanium tetrachloride, titanium tetrabromide, titanium tetraiodide, and titanium alkoxyhalides. More preferably, the alkyl titanium halide comprises one or more of the following: titanium methoxytrichloride, titanium ethoxytrichloride, titanium propoxytrichloride, titanium n-butoxytrichloride, titanium dimethoxydichloride, titanium diethoxydichloride, titanium dipropoxydichloride, titanium di n-butoxydichloride, titanium trimethoxytrichloride, titanium triethoxytrichloride, titanium tripropoxytrichloride, and titanium tri n-butoxytrichloride. Most preferably, the titanium compound is titanium tetrachloride.

7. The olefin polymerization catalyst according to claim 6, characterized in that, The molar ratio of the internal electron donor to the magnesium compound (calculated as magnesium) is 0.01-5.0, preferably 0.05-3.

0.

8. The olefin polymerization catalyst according to claim 1, characterized in that, The general formula of the organoaluminum compound is AlR c p X (3-p) , where R c It is hydrogen or C1-C 20 The hydrocarbon group, where X is a halogen and p is an integer 0 ≤ p ≤ 3; Preferably, the organoaluminum compound includes one or more of the following: trialkylaluminum compounds, alkylaluminum halides, alkylaluminum hydrides, alkylaluminum sesquichlorides, and alkylaluminoxanes. More preferably, the trialkylaluminum compound includes one or more of trimethylaluminum, triethylaluminum, triisobutylaluminum, tri-n-butylaluminum, tri-n-hexylaluminum, and trioctylaluminum; the alkylaluminum halide includes AlEt2Cl; the alkylaluminum sesquichloride includes Al2Et3Cl3; more preferably, the organoaluminum compound is a mixture of AlEt2Cl and Al2Et3Cl3.

9. The olefin polymerization catalyst according to claim 1, characterized in that, The molar ratio of the organoaluminum compound to the titanium atoms in the catalyst component is 1-1000:1, more preferably 50-800.

10. The olefin polymerization catalyst according to claim 1, characterized in that, The external electron donor is a siloxane compound; Preferably, the general formula of the siloxane compound is R' t Si(OR”) 4-t In this context, R' and R” are each independently selected from C1-C 18 The hydrocarbon group, where t is an integer 0 ≤ t ≤ 3; More preferably, R' and R” each contain heteroatoms; the heteroatoms include one or more combinations of N, O, S, P, and Si.

11. The olefin polymerization catalyst according to claim 10, characterized in that, The siloxane compounds include trimethylmethoxysilane, trimethylethoxysilane, tri-n-propylmethoxysilane, tri-n-propylethoxysilane, tri-n-butylmethoxysilane, triisobutylethoxysilane, tricyclohexylmethoxysilane, tricyclohexylethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, di-n-propyldimethoxysilane, diisopropyldimethoxysilane, di-n-propyldiethoxysilane, diisopropyldiethoxysilane, di-n-butyldiethoxysilane, diisobutyldiethoxysilane, di-n-butyldiethoxysilane, di-tert-butyldimethoxysilane, di-tert-butyldimethoxysilane, di-n-butyldimethoxysilane, diisobutyldimethoxysilane, di-tert-butyldiethoxysilane, di-n-butyldiethoxysilane, n ... Butylmethyldimethoxysilane, di(2-ethylhexyl)dimethoxysilane, di(2-ethylhexyl)diethoxysilane, dicyclohexyldimethoxysilane, dicyclohexyldiethoxysilane, dicyclopentyldimethoxysilane, dicyclopentyldiethoxysilane, cyclohexylmethyldimethoxysilane, cyclohexylmethyldiethoxysilane, cyclohexylethyldimethoxysilane, cyclohexylisopropyldimethoxysilane, cyclohexylethyldiethoxysilane, cyclopentylmethyldimethoxysilane, cyclopentylmethyldiethoxysilane, cyclopentylethyldiethoxysilane, cyclopentylisopropyldiethoxysilane, cyclopentylisobutyldimethoxysilane, cyclohexyl-n-propyldimethoxysilane, cyclohexyl-n-propyldimethoxysilane Ethoxysilane, cyclohexyl-n-butyldiethoxysilane, pentylmethyldimethoxysilane, diphenyldimethoxysilane, pentylmethyldiethoxysilane, pentylethyldimethoxysilane, pentylethyldiethoxysilane, cyclohexyldimethylmethoxysilane, cyclohexyldiethylmethoxysilane, cyclohexyldiethylmethoxysilane, cyclohexyldiethylethoxysilane, 2-ethylhexyltrimethoxysilane, cyclohexyldimethoxysilane, cyclohexyldiethoxysilane, 2-ethylhexyltriethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, n-propyltrimethoxysilane, n-propyltriethoxysilane, isopropyltrimethoxysilane, isopropyltriethoxysilane, n-butyltrimethoxysilane, isobutyltrimethoxysilane Silane, tert-butyltrimethoxysilane, n-butyltriethoxysilane, cyclohexyltrimethoxysilane, cyclohexyltriethoxysilane, cyclopentyltrimethoxysilane, cyclopentyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, 2-ethylhexyltrimethoxysilane, 2-ethylhexyltriethoxysilane, pentyltrimethoxysilane, pentyltriethoxysilane, phenyltriethoxysilane, tetramethoxysilane, tetraethoxysilane, cyclohexylcyclopentyldimethoxysilane, cyclohexylcyclopentyldiethoxysilane, cyclohexylcyclopentyldipropoxysilane, 3-methylcyclohexylcyclopentyldimethoxysilane, 4-methylcyclohexylcyclopentyldimethoxysilane, 3,5-dimethylcyclopentyldimethoxysilane, 3,One or more combinations of 5-dimethylcyclohexylcyclopentyldimethoxysilane, 3-methylcyclohexylcyclohexyldimethoxysilane, di(3-methylcyclohexyl)dimethoxysilane, 4-methylcyclohexylcyclohexyldimethoxysilane, di(4-methylcyclohexyl)dimethoxysilane, 3,5-dimethylcyclohexylcyclohexyldimethoxysilane, di(3,5-dimethylcyclohexyl)dimethoxysilane, tetrapropoxysilane, tetrabutoxysilane, methyl tert-butyldimethoxysilane, 2-ethylpiperidinyl-2-tert-butyldimethoxysilane, (1,1,1-trifluoro-2-propyl)-2-ethylpiperidinyldimethoxysilane, and (1,1,1-trifluoro-2-propyl)-methylmethoxysilane; Preferably, the siloxane compound comprises one or more combinations of di-n-propyl dimethoxysilane, diisopropyl dimethoxysilane, di-n-butyl dimethoxysilane, diisobutyl dimethoxysilane, di-tert-butyl dimethoxysilane, di-n-butyl diethoxysilane, tert-butyl trimethoxysilane, dicyclohexyl dimethoxysilane, dicyclohexyl diethoxysilane, cyclohexyl methyl dimethoxysilane, cyclohexyl ethyl diethoxysilane, cyclohexyl ethyl dimethoxysilane, cyclohexyl ethyl diethoxysilane, cyclopentyl methyl dimethoxysilane, cyclopentyl methyl diethoxysilane, cyclopentyl ethyl dimethoxysilane, cyclohexylcyclopentyl dimethoxysilane, cyclohexylcyclopentyl diethoxysilane, 3-methylcyclohexylcyclopentyl dimethoxysilane, 4-methylcyclohexylcyclopentyl dimethoxysilane, and 3,5-dimethylcyclopentyl dimethoxysilane. Alternatively, preferably, the siloxane compound comprises one or more combinations of cyclohexylmethyldimethoxysilane, diisopropyldimethoxysilane, di-n-butyldimethoxysilane, diisobutyldimethoxysilane, diphenyldimethoxysilane, phenyltriethoxysilane, methyl tert-butyldimethoxysilane, dicyclopentyldimethoxysilane, 2-ethylpiperidinyl-2-tert-butyldimethoxysilane, (1,1,1-trifluoro-2-propyl)-2-ethylpiperidinyldimethoxysilane, (1,1,1-trifluoro-2-propyl)-methyldimethoxysilane, cyclohexyltrimethoxysilane, tert-butyltrimethoxysilane, and tert-hexyltrimethoxysilane.

12. The olefin polymerization catalyst according to claim 1, characterized in that, The molar ratio of silicon in the external electron donor to titanium in the catalyst component is 0.002-100, preferably 0.01-20, and more preferably 0.01-5.

13. The olefin polymerization catalyst according to claim 1, characterized in that, The molar ratio of the piperidine ester to the external electron donor is (0.02-50):1, preferably (0.1-10):

1.

14. The use of a catalyst according to any one of claims 1-13 in olefin polymerization.

15. The application according to claim 14, characterized in that, The olefins include straight-chain or branched olefins, preferably one or more combinations of ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, 3-methyl-1-butene, 4-methyl-1-pentene, butadiene, vinylcyclopentene, and vinylcyclohexene.

16. The application according to claim 14, characterized in that, The polymerization includes the polymerization of ethylene and / or propylene.

17. The application according to claim 14, characterized in that, The polymerization includes homopolymerization or copolymerization.

18. The application according to claim 14, characterized in that, During the catalytic process, the order in which the components of the catalyst are added is arbitrary; Preferably, the organoaluminum compound is added to the polymerization system first, followed by the external electron donor and the activity modifier, and finally the catalyst component.

19. The application according to claim 14, characterized in that, The polymerization is carried out with or without a solvent; the olefin is in the gas phase or liquid phase; preferably, hydrogen is added or not added as a molecular weight regulator; the polymerization is a continuous polymerization or a batch polymerization, and the polymerization is carried out in one step, two steps or more steps.

20. The application according to claim 14, characterized in that, The polymerization temperature is ≤200℃, preferably 20-100℃, and more preferably 40-80℃; the polymerization pressure is ≤10MPa, preferably 0.3-5MPa.

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