Ziegler-Natta catalyst and application thereof

Abstract

The invention belongs to the field of chemical catalysis, and particularly relates to a Ziegler-Natta catalyst and application thereof. The Ziegler-Natta catalyst provided by the invention comprises the following components: (a) a catalytic component containing 10-25% of Mg, 1-10% of Ti, 40-60% of halogen and 1-30% of an internal electron donor compound; the internal electron donor compound is maleate with a structure as shown in a formula (I); (b) an aluminum alkyl compound; and (c) an external electron donor compound. The maleic acid ester compound with a special unsaturated heterocyclic structure is used as an internal electron donor, the unique electronic effect of the maleic acid ester compound enables the comprehensive performance of the catalyst to be excellent, when the maleic acid ester compound is used for propylene (co) polymerization, satisfactory polymerization yield can be obtained, the stereospecificity of a polymer is high, and the catalyst is suitable for being used for propylene (co) polymerization. Meanwhile, the catalyst has good sensitivity to hydrogen regulation, the molecular weight distribution of the obtained polymer is wide, and development of different grades of the polymer is facilitated. # imgabs0 #

Description

Technical Field

[0001] The invention belongs to the field of chemical catalysis, and in particular relates to a Ziegler-Natta catalyst and application thereof. Background Art

[0002] Supported Ziegler-Natta catalyst is a solid titanium catalyst with magnesium, titanium, halogen and electron donor as basic components. It is particularly suitable for the polymerization of α-olefins with 3 or more carbon atoms. The obtained olefin polymer has a high yield and stereoregularity. Electron donor is one of the essential components of supported Ziegler-Natta catalyst, which can effectively improve the activity and isotacticity of the catalyst. Polyolefin catalysts are constantly updated with the development of electron donor compounds.

[0003] A variety of electron donor compounds have been reported in the prior art, such as mono- or poly-carboxylic acid esters, anhydrides, ketones, mono- or poly-ethers, amines, and their derivatives. Currently, di-aromatic carboxylic acid ester compounds are more commonly used in industry, such as di-n-butyl phthalate or diisobutyl phthalate (PM Trivedi, et al. J. Polym. Res., 2021, 28, Article number: 45). Supported Ziegler-Natta catalysts with 1,3-diether compounds as electron donors are recognized as a new generation of electron donor compounds with high activity and isotacticity, such as 9,9-di(methoxymethyl)fluorene recently disclosed in CN1090194C, CN00103538, and CN1137155C. In addition, researchers have recently tried to use other compounds as electron donors in olefin polymerization catalyst components, such as 1,8-naphthalene diphenol esters reported by Chang et al. of BASF (WO2011084691A2 and US20110213106A1) and 1,2-benzenediphenol esters (US20190338054A1 and CN102325808A) structures disclosed by Dow. These electron donor-loaded catalysts have high activity and isotacticity. However, whether it is 1,3-diether or diol lipid compounds, the synthesis is difficult and costly, and no industrial reports have been seen so far. Summary of the invention

[0004] In view of this, the object of the present invention is to provide a Ziegler-Natta catalyst and its application. The catalyst provided by the present invention uses a maleate compound with a special unsaturated heterocyclic structure as an internal electron donor, and its unique electronic effect can make the comprehensive performance of the catalyst excellent. The synthesis route of the maleate compound is simple and easy to prepare.

[0005] The present invention provides a Ziegler-Natta catalyst comprising the following components:

[0006] (a) a catalyst component containing, by weight percentage, 10-25% Mg, 1-10% Ti, 40-60% halogen and 1-30% internal electron donor compound; the internal electron donor compound is a maleate of formula (I):

[0007]

[0008] In formula (I), R1 and R2 are independently selected from C1 to C 20 a linear or branched alkyl, alkenyl, cycloalkyl, aryl, arylalkyl or alkylaryl group containing or not containing heteroatoms; R3 to R6 are independently selected from hydrogen or C1 to C 20 a linear or branched alkyl, alkenyl, cycloalkyl, aryl, arylalkyl or alkylaryl group containing or not containing heteroatoms, R3 to R6 are independent groups or two or more groups among R3 to R6 are bonded to each other to form one or more condensed ring structures;

[0009] (b) an alkylaluminum compound;

[0010] (c) external electron donor compounds;

[0011] Calculated by the molar ratio of Ti, Al and the external electron donor compound, the dosage ratio of component a, component b and component c in the catalyst is 1:(5-1000):(0-1200).

[0012] Preferably, R1 and R2 are independently selected from C1 to C 10 The alkyl, cycloalkyl or arylalkyl groups are selected from the group consisting of:

[0013] Preferably, R1 and R2 are independently selected from isopropyl, n-butyl, isobutyl or neopentyl.

[0014] Preferably, at least two of the R3 to R6 groups are hydrogen.

[0015] Preferably, R3 and R4 are hydrogen.

[0016] Preferably, R5 and R6 are not hydrogen or alkyl at the same time.

[0017] Preferably, the internal electron donor compound is 4-methyl-1,4-cyclohexadiene-1,2-dicarboxylic acid dimethyl ester, 4-methoxy-1,4-cyclohexadiene-1,2-dicarboxylic acid diethyl ester, 4-formyl-1,4-cyclohexadiene-1,2-dicarboxylic acid diisopropyl ester, 4-methyl-1,4-cyclohexadiene-1,2-dicarboxylic acid di-n-butyl ester, 4-methoxy-1,4-cyclohexadiene-1,2-dicarboxylic acid diisobutyl ester, 3,4-dimethyl dineopentyl-1,4-cyclohexadiene-1,2-dicarboxylate, diisobutyl-3,5-dimethyl-1,4-cyclohexadiene-1,2-dicarboxylate, dineopentyl-3,4,5,6-tetramethyl-1,4-cyclohexadiene-1,2-dicarboxylate, diisobutyl-bicyclo[2.2.2]octa-2,5-diene-2,3-dicarboxylate or dineopentyl-1-methyl-bicyclo[2.2.2]octa-2,5-diene-2,3-dicarboxylate.

[0018] Preferably, the Mg in the catalyst component a is of the general formula Mg(OR') m X (2-m) · nROH is provided by a magnesium halide alcoholate, wherein R' is C1~C 20 alkyl, arylalkyl or aryl, X is halogen, m is an integer from 0 to 2, 0 < n < 6, R is C1 to C 20 An alkyl or arylalkyl group.

[0019] Preferably, the magnesium halide in the magnesium halide alcoholate is magnesium dichloride, magnesium dibromide, chloromethoxymagnesium or chloroethoxymagnesium; and the alcohol in the magnesium halide alcoholate is ethanol, n-propanol, isopropanol, n-butanol or isobutanol.

[0020] Preferably, the particle size distribution of the magnesium halide alcoholate is 20 to 250 μm.

[0021] Preferably, the Ti in the catalyst component a is of the general formula TiX n (OR) 4-n A titanium compound is provided, wherein R is a hydrocarbon group having 1 to 20 carbon atoms, X is a halogen, and n is an integer of 0 to 4.

[0022] Preferably, the titanium compound is titanium tetrachloride, titanium tetrabromide, titanium tetraiodide, titanium tetrabutoxide, titanium tetraethoxide, titanium triethoxide monochloride, titanium diethoxide dichloride or titanium triethoxide monochloride.

[0023] Preferably, the alkyl aluminum compound is a trialkyl aluminum compound.

[0024] Preferably, the trialkylaluminum compound is triethylaluminum, triisobutylaluminum, tri-n-butylaluminum, tri-n-hexylaluminum or tri-n-octylaluminum.

[0025] Preferably, the external electron donor compound is an organosilicon compound with the general formula R n Si(OR') 4-n , wherein n is an integer of 0 to 3, and R and R' are independently selected from an alkyl group, a cycloalkyl group or an aryl group containing or not containing heteroatoms.

[0026] Preferably, the organosilicon compound is trimethylmethoxysilane, trimethylethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, diphenyldimethoxysilane, diphenyldiethoxysilane, phenyltriethoxysilane, phenyltrimethoxysilane, vinyltrimethoxysilane, cyclohexylmethyldimethoxysilane, methyltert-butyldimethoxysilane, diisopropyldimethoxysilane, diisobutyldimethoxysilane, di-n-butyldimethoxysilane, dicyclopentyldimethoxysilane or di(cyclobutylmethyl)dimethoxysilane.

[0027] Preferably, based on the molar ratio of Ti, Al and the external electron donor compound, the usage ratio of component a, component b and component c in the catalyst is 1:(250-1000):(25-300).

[0028] The present invention provides an olefin polymerization method, comprising the following steps:

[0029] Olefins are polymerized in the presence of the Ziegler-Natta catalyst described in the technical solution to obtain polyolefins.

[0030] Compared with the prior art, the present invention provides a Ziegler-Natta catalyst and its application. The Ziegler-Natta catalyst provided by the present invention comprises the following components: (a) a catalytic component containing, by weight percentage, 10-25% Mg, 1-10% Ti, 40-60% halogen and 1-30% internal electron donor compound; the internal electron donor compound is a maleate of the formula (I), R1 and R2 are independently selected from C1-C 20 a linear or branched alkyl, alkenyl, cycloalkyl, aryl, arylalkyl or alkylaryl group containing or not containing heteroatoms; R3 to R6 are independently selected from hydrogen or C1 to C 20(a) a linear or branched alkyl, alkenyl, cycloalkyl, aryl, arylalkyl or alkylaryl group containing or not containing heteroatoms, R3-R6 are independent groups or two or more groups in R3-R6 are bonded to each other to form one or more condensed ring structures; (b) an alkyl aluminum compound; (c) an external electron donor compound; based on the molar ratio of Ti, Al and the external electron donor compound, the amount ratio of component a, component b and component c in the catalyst is 1:(5-1000):(0-1200). The present invention uses a maleate compound with a special unsaturated heterocyclic structure as an internal electron donor. Its unique electronic effect can make 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. In addition, the maleate compound used in the present invention can be obtained by a simple Diels-Alder reaction. The synthesis method is simple and easy to implement, which is convenient for popularization and application. DETAILED DESCRIPTION

[0031] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0032] The present invention provides a Ziegler-Natta catalyst comprising the following components:

[0033] (a) a catalyst component containing, by weight percentage, 10-25% Mg, 1-10% Ti, 40-60% halogen and 1-30% internal electron donor compound; the internal electron donor compound is a maleate of formula (I):

[0034]

[0035] In formula (I), R1 and R2 are independently selected from C1 to C 20 a linear or branched alkyl, alkenyl, cycloalkyl, aryl, arylalkyl or alkylaryl group containing or not containing heteroatoms; R3 to R6 are independently selected from hydrogen or C1 to C 20 a linear or branched alkyl, alkenyl, cycloalkyl, aryl, arylalkyl or alkylaryl group containing or not containing heteroatoms, R3 to R6 are independent groups or two or more groups among R3 to R6 are bonded to each other to form one or more condensed ring structures;

[0036] (b) an alkylaluminum compound;

[0037] (c) external electron donor compounds;

[0038] Calculated by the molar ratio of Ti, Al and the external electron donor compound, the dosage ratio of component a, component b and component c in the catalyst is 1:(5-1000):(0-1200).

[0039] In the catalyst provided by the present invention, in component a, the carbon number of R1 to R6 in the maleic acid ester of the formula (I) can be C1, C2, C3, C4, C5, C6, C7, C8, C9, C 10 , C 11 , C 12 , C 13 , C 14 , C 15 , C 16 , C 17 , C 18 , C 19 or C 20 .

[0040] In the catalyst provided by the present invention, in component a, R1 and R2 in the maleic acid ester of formula (I) are independently preferably selected from C1 to C 10 The alkyl group is an alkyl group, a cycloalkyl group or an arylalkyl group, and more preferably an isopropyl group, a n-butyl group, an isobutyl group or a neopentyl group.

[0041] In the catalyst provided by the present invention, in component a, preferably at least two groups among R3 to R6 in the maleate of the formula (I) are hydrogen, and more preferably R3 and R4 are hydrogen.

[0042] In the catalyst provided by the present invention, in component a, R5 and R6 in the maleate of the formula (I) are preferably not hydrogen or alkyl at the same time.

[0043] In the catalyst provided by the present invention, in component a, the maleate of the structure of formula (I) can be specifically 4-methyl-1,4-cyclohexadiene-1,2-dicarboxylic acid dimethyl ester, 4-methoxy-1,4-cyclohexadiene-1,2-dicarboxylic acid diethyl ester, 4-formyl-1,4-cyclohexadiene-1,2-dicarboxylic acid diisopropyl ester, 4-methyl-1,4-cyclohexadiene-1,2-dicarboxylic acid di-n-butyl ester, 4-methoxy-1,4-cyclohexadiene-1,2-dicarboxylic acid diisobutyl ester. ester, dineopentyl 3,4-dimethyl-1,4-cyclohexadiene-1,2-dicarboxylate, diisobutyl 3,5-dimethyl-1,4-cyclohexadiene-1,2-dicarboxylate, dineopentyl 3,4,5,6-tetramethyl-1,4-cyclohexadiene-1,2-dicarboxylate, diisobutyl bicyclo[2.2.2]octa-2,5-diene-2,3-dicarboxylate or dineopentyl 1-methyl-bicyclo[2.2.2]octa-2,5-diene-2,3-dicarboxylate.

[0044] In the catalyst provided by the present invention, in component a, the synthesis of the maleate (or its precursor) of the formula (I) can be prepared by the known Diels-Alder reaction, which will not be described in detail.

[0045] In the catalyst provided by the present invention, in component a, Mg is preferably represented by the general formula Mg(OR'): m X (2-m) · nROH is provided by a magnesium halide alcoholate, wherein R' is C1~C 20 alkyl, arylalkyl or aryl, X is halogen, m is an integer from 0 to 2, 0 < n < 6, R is C1 to C 20 Further, the carbon number of R' and R can be specifically C1, C2, C3, C4, C5, C6, C7, C8, C9, C 10 , C 11 , C 12 , C 13 , C 14 , C 15 , C 16 , C 17 , C 18 , C 19 or C 20 ; X can specifically be F, Cl, Br or I; m can specifically be 0, 1 or 2; n can specifically be 0.1, 0.2, 0.5, 0.7, 1, 1.2, 1.5, 1.7, 2, 2.3, 2.5, 2.7, 2.9, 3, 3.2, 3.5, 3.7, 4, 4.2, 4.5, 4.7, 5, 5.2, 5.5, 5.7 or 5.9.

[0046] In the catalyst provided by the present invention, in component a, the magnesium halide in the magnesium halide alcoholate is preferably magnesium dichloride, magnesium dibromide, chloromethoxymagnesium or chloroethoxymagnesium; the alcohol in the magnesium halide alcoholate is preferably ethanol, n-propanol, isopropanol, n-butanol or isobutanol, more preferably ethanol.

[0047] In the catalyst provided by the present invention, in component a, the particle size distribution of the magnesium halide alcoholate is preferably 20 to 250 μm, specifically 20 μm, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, 100 μm, 110 μm, 120 μm, 130 μm, 140 μm, 150 μm, 160 μm, 170 μm, 180 μm, 190 μm, 200 μm, 210 μm, 220 μm, 230 μm, 240 μm or 250 μm.

[0048] In the catalyst provided by the present invention, in component a, the magnesium halide alcoholate can be prepared by a method of thermally dissolving magnesium halide and alcohol, spraying at high pressure or stirring at high speed, and then solidifying into microsphere particles in a cooling medium.

[0049] In the catalyst provided by the present invention, in component a, Ti is preferably composed of the general formula TiX n (OR) 4-n A titanium compound is provided, wherein R is a hydrocarbon group having 1 to 20 carbon atoms, X is a halogen, and n is an integer of 0 to 4. Further, the carbon number of R can be specifically C1, C2, C3, C4, C5, C6, C7, C8, C9, C 10 , C 11 , C 12 , C 13 , C 14 , C 15 , C 16 , C 17 , C 18 , C 19 or C 20 ; X can specifically be F, Cl, Br or I; n can specifically be 0, 1, 2, 3 or 4.

[0050] In the catalyst provided by the present invention, in component a, the titanium compound is preferably titanium tetrachloride, titanium tetrabromide, titanium tetraiodide, tetrabutoxytitanium, tetraethoxytitanium, triethoxytitanium monochloride, diethoxytitanium dichloride or triethoxytitanium monochloride, more preferably titanium tetrachloride.

[0051] In the catalyst provided by the present invention, in component a, by weight percentage, the content of Mg can be specifically 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24% or 25%; the content of Ti can be specifically 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, 8%, 8.5%, 9%, 9.5% or 10%; the content of halogen (F, Cl, Br or I) can be specifically 40% , 41%, 42%, 43%, 44%, 45%, 46%, 47%, 48%, 49%, 50%, 51%, 52%, 53%, 54%, 55%, 56%, 57%, 58%, 59% or 60%; the content of the internal electron donor compound can be specifically 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29% or 30%.

[0052] In the catalyst provided by the present invention, the preparation method of component a preferably comprises the following steps:

[0053] (a) mixing a magnesium halide alcoholate with a titanium compound for reaction;

[0054] (b) heating the reaction system of step (a) and then adding the inner electron compound;

[0055] (c) heating the reaction system of step (b) and continuing the reaction for a period of time;

[0056] (d) filtering the reaction product of step (c), then mixing it with a certain amount of titanium compound for reaction, and then filtering, washing and drying to obtain component a.

[0057] In the above-mentioned preparation method of component a provided by the present invention, in step a), the molar ratio of Mg in the magnesium halide alcoholate to Ti in the titanium compound is preferably 1:(5-50), specifically 1:5, 1:10, 1:15, 1:20, 1:25, 1:30, 1:35, 1:40, 1:45 or 1:50; the reaction temperature is preferably -40-10°C, specifically -40°C, -35°C, -30°C, -25°C, -20°C, -15°C, -10°C, -5°C, 0°C, 5°C, 10°C; the reaction time is preferably 1-4h, specifically 1h, 1.5h, 2h, 2.5h, 3h, 3.5h or 4h.

[0058] In the method for preparing component a provided by the present invention, in step b), the terminal temperature of the heating is preferably 30-80°C, specifically 30°C, 35°C, 40°C, 45°C, 50°C, 55°C, 60°C, 65°C, 70°C, 75°C or 80°C; the molar ratio of Mg to the internal electron donor compound in the reaction system is preferably (2-15):1, specifically 2:1, 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1, 10:1, 11:1, 12:1, 13:1, 14:1 or 15:1.

[0059] In the method for preparing component a provided by the present invention, in step c), the terminal temperature of the heating is 100°C, 105°C, 110°C, 115°C, 120°C, 125°C, 130°C, 135°C, 140°C, 145°C or 150°C; and the reaction time is preferably 1h, 1.5h, 2h, 2.5h, 3h, 3.5h or 4h.

[0060] In the above-mentioned method for preparing component a provided by the present invention, in step d), the amount of the titanium compound used is preferably the same as that in step a); the reaction temperature is preferably 110-130°C, specifically 110°C, 115°C, 120°C, 125°C or 130°C; the reaction time is preferably 1h, 1.5h, 2h, 2.5h, 3h, 3.5h or 4h.

[0061] In the catalyst provided by the present invention, in component b, the alkylaluminum compound is preferably a trialkylaluminum compound, more preferably triethylaluminum, triisobutylaluminum, tri-n-butylaluminum, tri-n-hexylaluminum or tri-n-octylaluminum.

[0062] In the catalyst provided by the present invention, in component c, the external electron donor compound is preferably an organosilicon compound, and the general formula is preferably R n Si(OR') 4-n , wherein n is an integer of 0 to 3, and R and R' are independently selected from alkyl, cycloalkyl or aryl groups containing or not containing heteroatoms. Further, n can be 0, 1, 2 or 3.

[0063] In the catalyst provided by the present invention, in component c, the organosilicon compound is preferably trimethylmethoxysilane, trimethylethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, diphenyldimethoxysilane, diphenyldiethoxysilane, phenyltriethoxysilane, phenyltrimethoxysilane, vinyltrimethoxysilane, cyclohexylmethyldimethoxysilane, methyl tert-butyldimethoxysilane, diisopropyldimethoxysilane, diisobutyldimethoxysilane, di-n-butyldimethoxysilane, dicyclopentyldimethoxysilane or di(cyclobutylmethyl)dimethoxysilane.

[0064] In the catalyst provided by the present invention, component C 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 component C.

[0065] In the catalyst provided by the present invention, the molar ratio of Ti, Al and the external electron donor compound is preferably 1:(250-1000):(25-300); wherein the molar ratio of component a to component b (Ti / Al molar ratio) can be 1:250, 1:300, 1:350, 1:400, 1:450, 1:500, 1:550, 1:600, 1:700, 1:800, 1:900, 1:1000, 1:1100, 1:1200, 1:1300, 1:1400, 1:1500, 1:1600, 1:1700, 1:1800, 1:1900, 1:20 ... 0, 1:650, 1:700, 1:750, 1:800, 1:850, 1:900, 1:950 or 1:1000, and the dosage ratio of component a to component c (Ti / external electron donor compound molar ratio) can be specifically 1:25, 1:50, 1:75, 1:100, 1:125, 1:150, 1:175, 1:200, 1:225, 1:250, 1:275 or 1:300.

[0066] The present invention also provides an olefin polymerization method, comprising the following steps:

[0067] Olefins are polymerized in the presence of the Ziegler-Natta catalyst described in the technical solution to obtain polyolefins.

[0068] In the olefin polymerization method provided by the present invention, the polymerization is preferably homopolymerization of propylene or copolymerization of propylene with other olefins; in addition, it can also be copolymerization of ethylene with α-olefins (such as propylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene or 1-octene).

[0069] In the olefin polymerization method provided by the present invention, the polymerization reaction can be carried out in a liquid phase or a gas phase, or in a combined operation of liquid phase and gas phase polymerization stages.

[0070] In the olefin polymerization method provided by the present invention, the temperature of the polymerization reaction is preferably 0-150°C, more preferably 40-90°C, specifically 40°C, 45°C, 50°C, 55°C, 60°C, 65°C, 70°C, 75°C, 80°C, 85°C or 90°C; the pressure of the polymerization reaction is preferably 0.01-10MPa, specifically 0.01MPa, 0.1MPa, 0.5MPa, 1MPa, 1.5MPa, 2MPa, 2.5MPa, 3MPa, 3.5MPa, 4MPa, 4.5MPa, 5MPa, 6MPa, 7MPa, 8MPa, 9MPa or 10MPa.

[0071] In the olefin polymerization method provided by the present invention, hydrogen or other compounds that can act as chain transfer agents can be introduced during the polymerization reaction to control the molecular weight of the polymer.

[0072] The technical solution provided by the present invention adopts a maleate compound with a special unsaturated heterocyclic structure as an internal electron donor. Its unique electronic effect can make 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. In addition, the maleate compound used in the present invention can be obtained by a simple Diels-Alder reaction, and the synthesis method is simple and easy to implement, which is convenient for popularization and application.

[0073] For the purpose of greater clarity, the present invention is described in detail with reference to the following examples and comparative examples.

[0074] Examples 1 to 10 and Comparative Examples 1 to 2

[0075] (I) Synthesis of internal electron donors:

[0076] The monomer information involved in the internal electron donor in the embodiment is as follows: 2-methyl-1,3-butadiene, 2-methoxy-1,3-butadiene, 2-formyl-1,3-butadiene, 3-methyl-1,3-pentadiene, 2-methyl-1,3-pentadiene and 3,4-dimethyl-2,4-hexadiene, 1,4-cyclohexadiene and 3-methyl-1,4-cyclohexadiene and other dienes are obtained by commercial purchase; dimethyl butynedioate, diisopropyl butynedioate, di-n-butyl butynedioate, diisobutyl butynedioate and dineopentyl butynedioate are obtained by one-step esterification of butynedioic acid and the corresponding alcohol as reported in the literature (E. Aruna, et al. Macromol. Rapid Commun., 2014, 35, 666-671.).

[0077] Taking 4-methyl-1,4-cyclohexadiene-1,2-dicarboxylic acid dimethyl ester as an example, the specific synthesis method is as follows: 17.0 g of isoprene and 17.8 g of dimethyl butynedioate were added to a 150 mL flask and stirred at room temperature overnight. Column chromatography was performed to obtain 26.0 g of a colorless, transparent liquid product, 4-methyl-1,4-cyclohexadiene-1,2-dicarboxylic acid dimethyl ester, with a yield of 99%. 1 H NMR (TMS,CDCl3,400MHz) analysis results: δ5.40-5.37 (m,1H); δ3.76 (d,6H); δ3.01-2.96 (t,2H); δ2.90-2.85 (t,2H); δ1.69 (s,3H). The synthesis methods of other diester internal electron donors are similar to those of 4-methyl-1,4-cyclohexadiene-1,2-dicarboxylic acid dimethyl ester, with yields and 1The HNMR results are shown in the following table. The synthesis of internal electron donors can also be found in CN101824106A or CN101824108A.

[0078] Table 1. Yields and yields of internal electron donors synthesized via Diels-Alder reaction 1 HNMR results.

[0079]

[0080] (II) Preparation of catalytic component a:

[0081] TiCl4 was added to a dry glass reactor protected by nitrogen and cooled to -20°C. Microspherical magnesium chloride ethanolate (ethanol magnesium ratio of 2.9:1, average particle size of 30μm) carrier was added under stirring. The mixing ratio of carrier and TiCl4 was 1g:20mL. The reaction mixture was heated from -20°C to 0°C at a uniform rate, 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 Agilent8890A gas chromatograph; the titanium loading amount was determined according to the spectrophotometer.

[0082] (III) Propylene polymerization:

[0083] 0.25 mL (1 mmol) of external electron donor diphenyldimethoxysilane, 10.0 mL of a hexane solution of a co-catalyst triethylaluminum with a concentration of 1 mol / L, and 0.01 mmol (calculated as Ti) of the catalyst component a prepared by the present invention were added to a 5 L autoclave in sequence, 3 MPa of propylene and 0.2 MPa of hydrogen were added, stirred and mixed uniformly at room temperature, heated to 70° C., stirred for reaction for 2 h, the autoclave was opened and polypropylene was taken out, the polymer was cooled to room temperature, and the propylene was completely volatilized before being weighed, 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.

[0084] Table 2 Aggregation results

[0085]

[0086] a The Mg content in the catalyst was determined by EDTA titration; b The Cl content in the catalyst was measured by the Volhard method.

[0087] From the above results, it can be seen that the activity and isotacticity of the synthesized catalyst with maleate as internal electron donor are significantly better than those of the commercial dibutyl phthalate and dibutyl maleate supported catalysts.

[0088] In addition, the hydrogen tuning sensitivity was investigated using dineopentanol 4-methyl-1,4-cyclohexadiene-1,2-dicarboxylate as the internal electron donor. The results are shown in Table 2.

[0089] Table 3 Hydrogen adjustment sensitivity results

[0090]

[0091] From the above results, it can be seen that the synthesized catalyst with maleate as internal electron donor is sensitive to hydrogen, and its activity and isotacticity are still very high at higher hydrogen pressure.

[0092] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A Ziegler-Natta catalyst, characterized in that Includes the following components: (a) a catalyst component containing, by weight percentage, 10-25% Mg, 1-10% Ti, 40-60% halogen and 1-30% internal electron donor compound; the internal electron donor compound is a maleate of formula (I): In formula (I), R1 and R2 are independently selected from C1 to C 20 a linear or branched alkyl, alkenyl, cycloalkyl, aryl, arylalkyl or alkylaryl group containing or not containing heteroatoms; R3 to R6 are independently selected from hydrogen or C1 to C 20 a linear or branched alkyl, alkenyl, cycloalkyl, aryl, arylalkyl or alkylaryl group containing or not containing heteroatoms, R3 to R6 are independent groups or two or more groups among R3 to R6 are bonded to each other to form one or more condensed ring structures; (b) an alkylaluminum compound; (c) external electron donor compounds; Calculated by the molar ratio of Ti, Al and the external electron donor compound, the dosage ratio of component a, component b and component c in the catalyst is 1:(5-1000):(0-1200).

2. The Ziegler-Natta catalyst according to claim 1, characterized in that The R1 and R2 are independently selected from C1 to C 10 The alkyl, cycloalkyl or arylalkyl groups are selected from the group consisting of:

3. The Ziegler-Natta catalyst according to claim 2, characterized in that The R1 and R2 are independently selected from isopropyl, n-butyl, isobutyl or neopentyl.

4. The Ziegler-Natta catalyst according to claim 1, characterized in that At least two of the R3 to R6 groups are hydrogen.

5. The Ziegler-Natta catalyst according to claim 4, characterized in that The R3 and R4 are hydrogen.

6. The Ziegler-Natta catalyst according to claim 1, characterized in that The R5 and R6 are not hydrogen or alkyl at the same time.

7. The Ziegler-Natta catalyst according to claim 1, characterized in that The internal electron donor compound is 4-methyl-1,4-cyclohexadiene-1,2-dicarboxylic acid dimethyl ester, 4-methoxy-1,4-cyclohexadiene-1,2-dicarboxylic acid diethyl ester, 4-formyl-1,4-cyclohexadiene-1,2-dicarboxylic acid diisopropyl ester, 4-methyl-1,4-cyclohexadiene-1,2-dicarboxylic acid di-n-butyl ester, 4-methoxy-1,4-cyclohexadiene-1,2-dicarboxylic acid diisobutyl ester, 3,4-dimethyl- Dineopentyl-1,4-cyclohexadiene-1,2-dicarboxylate, diisobutyl-3,5-dimethyl-1,4-cyclohexadiene-1,2-dicarboxylate, dineopentyl-3,4,5,6-tetramethyl-1,4-cyclohexadiene-1,2-dicarboxylate, diisobutyl-bicyclo[2.2.2]octa-2,5-diene-2,3-dicarboxylate or dineopentyl-1-methyl-bicyclo[2.2.2]octa-2,5-diene-2,3-dicarboxylate.

8. The Ziegler-Natta catalyst according to claim 1, characterized in that The Mg in the catalyst component a is represented by the general formula Mg(OR') m X (2-m) · nROH is provided by a magnesium halide alcoholate, wherein R' is C1~C 20 alkyl, arylalkyl or aryl, X is halogen, m is an integer from 0 to 2, 0 < n < 6, R is C1 to C 20 An alkyl or arylalkyl group.

9. The Ziegler-Natta catalyst according to claim 8, characterized in that The magnesium halide in the magnesium halide alcoholate is magnesium dichloride, magnesium dibromide, chloromethoxymagnesium or chloroethoxymagnesium; the alcohol in the magnesium halide alcoholate is ethanol, n-propanol, isopropanol, n-butanol or isobutanol.

10. The Ziegler-Natta catalyst according to claim 8, characterized in that The particle size distribution of the magnesium halide alcoholate is 20 to 250 μm.

11. The Ziegler-Natta catalyst according to claim 1, characterized in that The Ti in the catalyst component a is represented by the general formula TiX n (OR) 4-n A titanium compound is provided, wherein R is a hydrocarbon group having 1 to 20 carbon atoms, X is a halogen, and n is an integer of 0 to 4.

12. The Ziegler-Natta catalyst according to claim 11, characterized in that The titanium compound is titanium tetrachloride, titanium tetrabromide, titanium tetraiodide, titanium tetrabutoxide, titanium tetraethoxide, titanium triethoxide monochloride, titanium diethoxide dichloride or titanium triethoxide monochloride.

13. The Ziegler-Natta catalyst according to claim 1, characterized in that The alkylaluminum compound is a trialkylaluminum compound.

14. The Ziegler-Natta catalyst according to claim 13, characterized in that The trialkylaluminum compound is triethylaluminum, triisobutylaluminum, tri-n-butylaluminum, tri-n-hexylaluminum or tri-n-octylaluminum.

15. The Ziegler-Natta catalyst according to claim 1, characterized in that The external electron donor compound is an organic silicon compound, the general formula of which is R n Si(OR') 4-n , wherein n is an integer of 0 to 3, and R and R' are independently selected from an alkyl group, a cycloalkyl group or an aryl group containing or not containing heteroatoms.

16. The Ziegler-Natta catalyst according to claim 15, characterized in that The organosilicon compound is trimethylmethoxysilane, trimethylethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, diphenyldimethoxysilane, diphenyldiethoxysilane, phenyltriethoxysilane, phenyltrimethoxysilane, vinyltrimethoxysilane, cyclohexylmethyldimethoxysilane, methyltert-butyldimethoxysilane, diisopropyldimethoxysilane, diisobutyldimethoxysilane, di-n-butyldimethoxysilane, dicyclopentyldimethoxysilane or di(cyclobutylmethyl)dimethoxysilane.

17. The Ziegler-Natta catalyst according to claim 1, characterized in that Calculated by the molar ratio of Ti, Al and the external electron donor compound, the dosage ratio of component a, component b and component c in the catalyst is 1:(250-1000):(25-300).

18. An olefin polymerization method, characterized in that: The following steps are involved: Olefins are polymerized in the presence of the Ziegler-Natta catalyst according to any one of claims 1 to 17 to obtain polyolefins.

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