External electron donor composition for ethylene polymerization and use thereof

Abstract

The invention discloses an external electron donor composition for ethylene polymerization, which consists of (1) 1, 2-dibromo hydrocarbon, (2) 1, 2, 3-tribromo hydrocarbon and (3) bromo ester. When the external electron donor is used for ethylene polymerization, the hydrogen regulation sensitivity of a catalyst can be remarkably improved, and high-melt-index polyethylene is prepared.

Description

Technical Field

[0001] The invention belongs to the technical field of polyolefin production, and particularly relates to an external electron donor composition for ethylene polymerization and a use method thereof. Background Art

[0002] High melt index polyethylene (HMI) typically refers to polyethylene with a melt index exceeding 20 g / 10 min. It has a wide range of applications, such as the production of fibers, large injection molded parts, and thin-walled injection molded parts. It is widely used in the textile, papermaking, packaging, transportation, machinery, chemical, mining, petroleum, agriculture, construction, electrical, food, medical, and sports industries. Linear low-density polyethylene (LLDPE) and high-density polyethylene (HDPE) within HMI are generally produced using a Ziegler-Natta catalyst system, primarily composed of MgCl2-supported TiCl4. Hydrogen is added as a molecular weight regulator during the ethylene polymerization process. To produce HMI polyethylene, large amounts of ethylene are typically added, resulting in a gaseous partial pressure of ethylene that is nearly identical to that of hydrogen. This results in decreased catalyst activity, increased fines content, and increased hydrogen circulation, which can also impact production safety.

[0003] In polyethylene catalyst systems, there are also reports of using regulators. For example, in CN1129617C, a solid component containing MgCl2, TiCl4, and SiO2 is reacted with chlorobenzene or fluorobenzene for 30-40 minutes to form a catalyst, which is then reacted with ethylene to produce polyethylene, thereby improving the activity of the catalyst. In CN1177872C, a Ti catalyst component, a V catalyst component, an alkyl aluminum, and a halogenated alkane such as chloroform are used to form a catalyst system for producing bimodal polyethylene. In CN1934142B, a catalyst component containing MgCl2 and TiCl4 is reacted with a monosubstituted chloroalkane to broaden the molecular weight distribution of polyethylene. In CN101139407B, MgCl2 and TiCl4 components are contacted with chloroalkane and silane to form a catalyst solid component, which is then reacted with an alkyl aluminum to catalyze ethylene polymerization. In CN105330770B, a solid component containing MgCl2 and TiCl4 is added to a reactor along with an aluminum alkyl and a chloroalkane to catalyze ethylene polymerization. The chloroalkane can enhance catalyst activity. In these studies, chloroalkane, either as a solid catalyst component or added during polymerization, enhances catalyst activity and is a valuable modifier for polyolefin catalysts. Summary of the Invention

[0004] In order to improve the above technical problems, the present invention provides an external electron donor composition for ethylene polymerization, comprising:

[0005] (1) 1,2-dibromocarbon,

[0006] (2) 1,2,3-tribromocarbon, and

[0007] (3) Bromoester composition;

[0008] The 1,2-dibromocarbon is a C-(2-bromocarbon) substituted by two bromine atoms at positions 1 and 2 according to the systematic nomenclature. 1-20 Alkanes, C 2-20 Olefins, C 2-20 Alkynes, C 3-20 Cycloalkanes, C 3-20 Cycloolefins, C 3-20 Cycloalkynes, C 6-20 aromatic hydrocarbons;

[0009] The 1,2,3-tribromocarbon refers to a C-(2,3-tribromocarbon) in which positions 1, 2 and 3 are substituted by three bromine atoms according to the systematic nomenclature. 1-20 Alkanes, C 2-20 Olefins, C 2-20 Alkynes, C 3-20 Cycloalkanes, C 3-20 Cycloolefins, C 3-20 Cycloalkynes, C 6-20 aromatic hydrocarbons;

[0010] The bromoester is selected from the following groups substituted by 1, 2 or more bromine atoms: R1-C(O)O-R2, R3-P(O)(OR 31 )(OR 32 ); R1, R2, R3, R 31 and R 32 The same or different, independently selected from H, C 1-20 Alkyl, C 6-20 Aryl.

[0011] According to an embodiment of the present invention, the 1,2-dibromocarbon refers to a C 1-10 Alkanes, C 2-10 Olefins, C 3-10 Cycloalkanes, C 6-10 Aromatic hydrocarbons.

[0012] According to an embodiment of the present invention, the 1,2-dibromohydrocarbon is selected from one or more of 1,2-dibromoethane, 1,2-dibromopropane, 2,3-dibromopropylene, 1,2-dibromobutane, 1,2-dibromopentane, 1,2-dibromohexane, 1,2-dibromoheptane, 1,2-dibromocyclohexane, 1,2-dibromobenzene, and halogen-substituted or alkane-substituted 1,2-dibromobenzene.

[0013] According to an embodiment of the present invention, the 1,2,3-tribromocarbon refers to a C-1,2,3-tribromocarbon in which positions 1, 2 and 3 are substituted by three bromine atoms according to the systematic nomenclature. 1-10 Alkanes, C 2-10 Olefins, C 3-10Cycloalkanes, C 6-10 Aromatic hydrocarbons.

[0014] According to an embodiment of the present invention, the 1,2,3-tribromohydrocarbon is selected from at least one of 1,2,3-tribromopropane, 1,2,3-tribromobutane, 1,2,3-tribromopentane, 1,2,3-tribromohexane, 1,2,3-tribromoheptane and 1,2,3-tribromooctane.

[0015] According to an embodiment of the present invention, R1, R2, R3, R 31 and R 32 The same or different, independently selected from H, C 1-10 Alkyl, C 6-10 aryl;

[0016] According to an embodiment of the present invention, R1, R2, R3, R 31 and R 32 The same or different, independently selected from H, methyl, ethyl, propyl, isopropyl, butyl, tert-butyl, pentyl, isopentyl, hexyl, phenyl.

[0017] According to an embodiment of the present invention, the bromoester is selected from one or more of 2-bromoacetate, 2-bromoisobutyrate, 2-bromoisovalerate, 4-bromobenzoate, carboxylic acid ester of 2,4,6-tribromophenol, carboxylic acid ester of 2,3-dibromopropanol, and phosphate ester of 2,3-dibromopropanol; preferably at least one of methyl 4-bromobenzoate, ethyl 4-bromobenzoate, propyl 4-bromobenzoate, isopropyl 4-bromobenzoate, isopropyl 2-bromoacetate, isopropyl 2-bromoisovalerate, and 2,3-dibromopropyl acetate.

[0018] According to an embodiment of the present invention, the molar ratio of the 1,2-dibromocarbon in the composition is not higher than 95%, for example, 50%-92%, such as 90%, 85%, 80%, 75%.

[0019] According to an embodiment of the present invention, the molar ratio of the 1,2,3-tribromocarbon in the composition is not higher than 10%, for example, 1%-8%, such as 6%, 5%, 4%, 3%, 2%, or 1%.

[0020] According to an embodiment of the present invention, the molar ratio of the brominated ester in the composition is not higher than 30%, for example, not higher than 2%-20%, such as 15%, 10%, or 5%.

[0021] According to an embodiment of the present invention, the molar ratio of the 1,2-dibromocarbon in the composition is 80%-90%, the molar ratio of the 1,2,3-tribromocarbon in the composition is 1%-5%, and the molar ratio of the bromoester in the composition is 8%-15%.

[0022] The present invention also provides an ethylene polymerization method, which comprises adding the external electron donor composition for ethylene polymerization into an ethylene polymerization reaction.

[0023] According to an embodiment of the present invention, the ethylene polymerization method includes the following steps: mixing the catalyst component (A), the alkyl aluminum compound (B) and the external electron donor composition (C) for ethylene polymerization and adding them to a reactor, reacting with ethylene and its copolymerized olefin monomers, and adding hydrogen as a molecular weight regulator to prepare a polyethylene homopolymer or copolymer.

[0024] According to an embodiment of the present invention, the catalyst component (A) is a dry powder catalyst or a slurry catalyst, containing components such as MgCl2, TiCl4 and / or SiO2, such as XY-S (a catalyst produced by Yingkou Xiangyang Catalyst Co., Ltd.) and XY-H (a catalyst produced by Yingkou Xiangyang Catalyst Co., Ltd.).

[0025] According to an embodiment of the present invention, the alkylaluminum compound (B) is selected from alkylaluminum or alkylaluminum chloride, and the alkylaluminum compound is, for example, selected from one or more of trimethylaluminum, triethylaluminum, tri-n-butylaluminum, triisobutylaluminum, triisopropylaluminum, tri-tert-butylaluminum, tripentylaluminum, diethylaluminum chloride, and ethylaluminum dichloride.

[0026] According to an embodiment of the present invention, the catalyst composed of the catalyst component (A) and the alkylaluminum compound (B) is a titanium chloride / alkylaluminum catalyst, such as a Ziegler-Natta catalyst.

[0027] According to an embodiment of the present invention, the co-olefin monomer is selected from C 2-20 Olefins, such as C 2-10 Olefins, preferably 1-(C 2-10 olefins), more preferably propylene, 1-butene, 1-hexene and 1-octene.

[0028] According to an embodiment of the present invention, the molar ratio of the external electron donor composition (C) to Ti in the catalyst component (A) is 5-100, preferably 5-50, more preferably 5-30, such as 10, 15, 20, 25, 30.

[0029] According to an embodiment of the present invention, the polymerization method applicable to the ethylene polymerization method includes gas phase polymerization, slurry polymerization, solution polymerization and / or a combination thereof.

[0030] According to an embodiment of the present invention, the reaction temperature in the ethylene polymerization method is 20°C to 120°C, preferably the reaction temperature is 60°C to 100°C, such as 70°C, 80°C, or 90°C.

[0031] According to an embodiment of the present invention, the reaction pressure in the ethylene polymerization method is 0.1-10 MPa, preferably 0.1-5 MPa, such as 0.5 MPa, 1 MPa, 2 MPa.

[0032] According to an embodiment of the present invention, the partial pressure of hydrogen in the ethylene polymerization method is 0.05-1 MPa, preferably 0.1-0.5 MPa, such as 0.2 MPa, 0.3 MPa, 0.4 MPa.

[0033] Beneficial effects

[0034] The present invention provides an external electron donor composition capable of improving the hydrogen modulation sensitivity of a catalytic ethylene polymerization catalyst (such as a Ziegler-Natta catalyst). The composition comprises 1,2-dibromocarbon, 1,2,3-tribromocarbon and a bromoester. Under the combined action of these three types of external electron donors, the catalyst has better hydrogen modulation sensitivity and can be used to prepare high melt index polyethylene.

[0035] Definitions and Explanations of Terms

[0036] Unless otherwise indicated, the definitions of groups and terms in this specification and claims, including definitions used as examples, exemplary definitions, preferred definitions, definitions in tables, and definitions of specific compounds in the Examples, may be arbitrarily combined and coupled with one another. The group definitions and compound structures resulting from such combinations and couplings should be understood to be within the scope of this specification and / or claims.

[0037] The term "C 1-20 "Alkyl" is understood to mean a straight-chain or branched saturated monovalent hydrocarbon group having 1 to 20 carbon atoms. For example, "C 1-10 "Alkyl" means straight-chain and branched alkyl groups having 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10 carbon atoms, preferably "C 1-8 Alkyl" or "C 1-6 Alkyl". "C 1-8 "Alkyl" means straight chain and branched chain alkyl groups having 1, 2, 3, 4, 5, 6, 7, or 8 carbon atoms, "C 1-6The term "alkyl" refers to straight-chain and branched alkyl groups having 1, 2, 3, 4, 5 or 6 carbon atoms. The alkyl group is, for example, methyl, ethyl, propyl, butyl, pentyl, hexyl, isopropyl, isobutyl, sec-butyl, tert-butyl, isopentyl, 2-methylbutyl, 1-methylbutyl, 1-ethylpropyl, 1,2-dimethylpropyl, neopentyl, 1,1-dimethylpropyl, 4-methylpentyl, 3-methylpentyl, 2-methylpentyl, 1-methylpentyl, 2-ethylbutyl, 1-ethylbutyl, 3,3-dimethylbutyl, 2,2-dimethylbutyl, 1,1-dimethylbutyl, 2,3-dimethylbutyl, 1,3-dimethylbutyl or 1,2-dimethylbutyl, or the like or isomers thereof.

[0038] The term "C 6-20 "Aryl" should be understood to preferably mean a monovalent aromatic or partially aromatic monocyclic, bicyclic (such as fused, bridged, spiro) or tricyclic hydrocarbon ring having 6 to 20 carbon atoms, which can be a single aromatic ring or a polyaromatic ring fused together, preferably "C 6-14 Aryl". The term "C 6-14 "Aryl" is understood to mean preferably a monovalent aromatic or partially aromatic monocyclic, bicyclic or tricyclic hydrocarbon ring ("C 6-14 or a ring having 9 carbon atoms ("C9 aryl"), for example indanyl or indenyl, or a ring having 10 carbon atoms ("C 10 aryl) such as tetrahydronaphthyl, dihydronaphthyl or naphthyl, or a ring having 13 carbon atoms ("C 13 aryl), such as fluorenyl, or a ring having 14 carbon atoms ("C 14 aryl”), such as anthracenyl. When the C 6-20 When the aryl group is substituted, it may be monosubstituted or polysubstituted. Furthermore, there is no limitation on the position of substitution, and for example, substitution may be at the ortho, para or meta position. DETAILED DESCRIPTION

[0039] The technical solutions of the present disclosure will be further described in detail below with reference to specific embodiments. It should be understood that the following embodiments are merely illustrative and explanations of the present disclosure and should not be construed as limiting the scope of protection of the present disclosure. All technologies implemented based on the above content of the present disclosure are included within the scope of protection intended by the present disclosure.

[0040] Unless otherwise specified, the raw materials and reagents used in the following examples are commercially available or can be prepared by known methods.

[0041] 1. In the following examples, the polymerization activity was calculated by the following method:

[0042] The unit of polymerization activity is g PE / g Cat.h.

[0043] 2. The melt index of polyethylene was tested using a 6542 melt flow rate meter from Geast, Italy, in accordance with GB / T3682-2000, at a temperature of 190°C and a weight of 2.16 kg.

[0044] Example 1:

[0045] A 5L reactor was heated and evacuated to remove air and water, then replaced with nitrogen. This process was repeated four times, followed by the addition of 3.5L of n-hexane. The reactor was then charged with 100mg of a Ziegler-Natta catalyst (primarily composed of MgCl2-supported TiCl4, Yingkou Xiangyang Catalyst XY-S), triethylaluminum, and an external electron donor mixture. The molar ratio of triethylaluminum to Ti in the catalyst was 100, and the molar ratio of the external electron donor mixture to Ti in the catalyst was 30. The molar ratio of 1,2-dibromoethane:1,2,3-tribromoethylene:2-bromoacetate in the external electron donor was 90:2:8. The reaction temperature was then heated to 90°C. Hydrogen was added all at once to a partial pressure of 0.2 MPa. Ethylene gas was then continuously added to maintain the reactor pressure at 1.0 MPa. After 1 hour of polymerization, the ethylene addition was stopped, the reaction mixture was cooled, and the product was filtered and dried to obtain a polyethylene product. The polymerization test results are shown in the table below.

[0046] Examples 2-14

[0047] Polyethylene was prepared by the same method as in Example 1, except that the type of solid catalyst (A), the amount of hydrogen added, the molar ratio of halogenated alkane to titanium in the catalyst, and the ratio of the three in the external electron donor composition were changed.

[0048] Comparative Examples 1-4

[0049] Polyethylene was prepared by the same method as in Example 1, except that a single external electron donor was used or no external electron donor was used. The experimental conditions and results are shown in Table 1.

[0050] Table 1 Experimental conditions and experimental results of Examples 1-14 and Comparative Examples 1-4

[0051]

[0052] Note: Catalyst 1: Yingkou Xiangyang Catalyst Co., Ltd. XY-S; Catalyst 2: Yingkou Xiangyang Catalyst Co., Ltd. XY-H.

[0053] The results show that the external electron donor composition for ethylene polymerization of the present invention has better hydrogen modulation sensitivity and can be effectively used to prepare high melt index polyethylene.

[0054] The above is an exemplary description of the implementation methods of the technical solutions disclosed herein. It should be understood that the scope of protection of the present disclosure is not limited to the above-mentioned implementation methods. Any modifications, equivalent substitutions, improvements, etc. made by those skilled in the art within the spirit and principles of the present disclosure shall be included in the scope of protection of the claims of this application.

Claims

1. An external electron donor composition for ethylene polymerization, comprising: (1) 1,2-dibromocarbon, (2) 1,2,3-tribromocarbon, and (3) Bromoester composition; The 1,2-dibromocarbon is a C-(2-bromocarbon) substituted by two bromine atoms at positions 1 and 2 according to the systematic nomenclature. 1-20 Alkanes, C 2-20 Olefins, C 2-20 Alkynes, C 3-20 Cycloalkanes, C 3-20 Cycloolefins, C 3-20 Cycloalkynes, C 6-20 aromatic hydrocarbons; The 1,2,3-tribromocarbon refers to a C-(2,3-tribromocarbon) in which positions 1, 2 and 3 are substituted by three bromine atoms according to the systematic nomenclature. 1-20 Alkanes, C 2-20 Olefins, C 2-20 Alkynes, C 3-20 Cycloalkanes, C 3-20 Cycloolefins, C 3-20 Cycloalkynes, C 6-20 aromatic hydrocarbons; The bromoester is selected from the following groups substituted by 1, 2 or more bromine atoms: R1-C(O)O-R2, R3-P(O)(OR 31 )(OR 32 ); R1, R2, R3, R 31 and R 32 The same or different, independently selected from H, C 1-20 Alkyl, C 6-20 Aryl.

2. The composition according to claim 1, characterized in that The 1,2-dibromocarbon is a C-(2-bromocarbon) substituted by two bromine atoms at positions 1 and 2 according to the systematic nomenclature. 1-10 Alkanes, C 2-10 Olefins, C 3-10 Cycloalkanes, C 6-10 aromatic hydrocarbons; Preferably, the 1,2-dibromohydrocarbon is selected from one or more of 1,2-dibromoethane, 1,2-dibromopropane, 2,3-dibromopropylene, 1,2-dibromobutane, 1,2-dibromopentane, 1,2-dibromohexane, 1,2-dibromoheptane, 1,2-dibromocyclohexane, 1,2-dibromobenzene, and halogen-substituted or alkane-substituted 1,2-dibromobenzene.

3. The composition according to claim 1 or 2, characterized in that The 1,2,3-tribromocarbon refers to a C-(2,3-tribromocarbon) in which positions 1, 2 and 3 are substituted by three bromine atoms according to the systematic nomenclature. 1-10 Alkanes, C 2-10 Olefins, C 3-10 Cycloalkanes, C 6-10 aromatic hydrocarbons; Preferably, the 1,2,3-tribromohydrocarbon is at least one selected from 1,2,3-tribromopropane, 1,2,3-tribromobutane, 1,2,3-tribromopentane, 1,2,3-tribromohexane, 1,2,3-tribromoheptane, and 1,2,3-tribromooctane.

4. The composition according to any one of claims 1 to 3, characterized in that R1, R2, R3, R 31 and R 32 The same or different, independently selected from H, C 1-10 Alkyl, C 6-10 aryl; Preferably, R1, R2, R3, R 31 and R 32 The same or different, independently selected from H, methyl, ethyl, propyl, isopropyl, butyl, tert-butyl, pentyl, isopentyl, hexyl, phenyl.

5. The composition according to any one of claims 1 to 4, characterized in that The bromoester is selected from one or more of 2-bromoacetate, 2-bromoisobutyrate, 2-bromoisovalerate, 4-bromobenzoate, carboxylic acid ester of 2,4,6-tribromophenol, carboxylic acid ester of 2,3-dibromopropanol, and phosphate ester of 2,3-dibromopropanol; preferably at least one of methyl 4-bromobenzoate, ethyl 4-bromobenzoate, propyl 4-bromobenzoate, isopropyl 4-bromobenzoate, isopropyl 2-bromoacetate, isopropyl 2-bromoisovalerate, and 2,3-dibromopropyl acetate.

6. The composition according to any one of claims 1 to 5, characterized in that The molar ratio of the 1,2-dibromocarbon in the composition is not higher than 95%; Preferably, the molar ratio of the 1,2,3-tribromocarbon in the composition is not higher than 10%, for example 1% to 8%; Preferably, the molar ratio of the brominated ester in the composition is not higher than 30%, for example, not higher than 2%-20%; Preferably, the molar ratio of the 1,2-dibromocarbon in the composition is 80%-90%, the molar ratio of the 1,2,3-tribromocarbon in the composition is 1%-5%, and the molar ratio of the bromoester in the composition is 8%-15%.

7. An ethylene polymerization method, comprising adding the external electron donor composition for ethylene polymerization into an ethylene polymerization reaction.

8. The method according to claim 7, characterized in that The ethylene polymerization method comprises the following steps: mixing a catalyst component (A), an alkyl aluminum compound (B) and the external electron donor composition (C) for ethylene polymerization, adding the mixture into a reactor, reacting the mixture with ethylene and its co-olefin monomers, and adding hydrogen as a molecular weight regulator to prepare a polyethylene homopolymer or copolymer. The catalyst component (A) is a dry powder catalyst or a slurry catalyst, containing components such as MgCl2, TiCl4 and / or SiO2, such as XY-S, XY-H. The alkylaluminum compound (B) is selected from alkylaluminum or alkylaluminum chloride, and the alkylaluminum compound is, for example, selected from one or more of trimethylaluminum, triethylaluminum, tri-n-butylaluminum, triisobutylaluminum, triisopropylaluminum, tri-tert-butylaluminum, tripentylaluminum, diethylaluminum chloride, and ethylaluminum dichloride; Preferably, the catalyst composed of the catalyst component (A) and the alkyl aluminum compound (B) is a titanium chloride / alkyl aluminum catalyst, such as a Ziegler-Natta catalyst. Preferably, the coolefin monomer is selected from C 2-20 Olefins, such as C 2-10 Olefins, preferably 1-(C 2-10 olefins), more preferably propylene, 1-butene, 1-hexene and 1-octene.

9. The method according to claim 7 or 8, characterized in that The molar ratio of the external electron donor composition (C) to Ti in the catalyst component (A) is 5 to 100, preferably 5 to 50, more preferably 5 to 30; Preferably, the polymerization method applicable to the ethylene polymerization method includes gas phase polymerization, slurry polymerization, solution polymerization and / or a combination thereof.

10. The method according to any one of claims 7 to 9, characterized in that: The reaction temperature in the ethylene polymerization method is 20°C to 120°C, preferably 60°C to 100°C; Preferably, the reaction pressure in the ethylene polymerization method is 0.1-10 MPa, preferably 0.1-5 MPa; Preferably, the partial pressure of hydrogen in the ethylene polymerization process is 0.05-1 MPa, preferably 0.1-0.5 MPa.

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