WO2019144976A2

WO2019144976A2 - Ziegler-natta catalyst having dual-function external electron donor, and application thereof

Info

Publication number: WO2019144976A2
Application number: PCT/CN2019/085594
Authority: WO
Inventors: 王立才; 高占先; 闫磊; 于丽梅; 李阳; 王焕; 李伟; 郑国彤; 董庆新; 原哲
Original assignee: 营口市向阳催化剂有限责任公司; 大连理工大学
Priority date: 2019-04-26
Filing date: 2019-05-06
Publication date: 2019-08-01
Also published as: WO2019144976A3; CN110003367A; CN110003367B

Abstract

Disclosed are an alpha-olefin polymerisation Z-N catalyst, and an application thereof, specifically an industrial production catalyst which consists of (A) a solid catalyst component, (B) a cocatalyst organoaluminium compound and (C) a dual-function external electron donor compound, and is used for alpha-olefin polymerisation or copolymerisation processes. The catalyst component comprises magnesium chloride as a carrier, a transition metal such as titanium and a composite aromatic diacid diester/1,3-diether as an internal electron donor. One or more organoaluminiums act as a cocatalyst. The dual-function external electron donor is a composite of a composite external electron donor hydrocarbyl meth(eth)oxy silicon and a polymerisation temperature control agent organic acid ester. The Z-N catalyst is used for alpha-olefin polymerisation or copolymerisation reactions, self-controls the polymerisation reaction rate during high-temperature polymerisation, maintains a stable reactor operation, and stabilises polymer performance.

Description

Ziegler-Natta catalyst with dual function external electron donor and application thereof

Technical field

The invention belongs to the technical field of preparation and application of α-olefin polymerization catalysts, and particularly relates to a bifunctional external electron donor for Ziegler-Natta (Z-N) catalyst for polymerization or copolymerization of α-olefins and an application thereof.

Background technique

The Z-N catalyst system has been continuously developed since its inception and has become the main body of the catalyst system for industrial olefin polymerization. Its development mainly goes through three stages: advancement of the preparation process of the carrier, development of the internal electron donor and improvement of the external electron donor. As an internal electron donor that promotes the development of ZN catalysts, monobasic acid esters of third-generation ZN catalysts, such as ethyl benzoate and ethyl p-ethoxybenzoate, have developed to dibasic acid esters, such as fourth-generation ZN. The comprehensive performance of the catalyst is good, such as di(iso)butyl phthalate, etc., and the 1,3-diether of the fifth-generation ZN catalyst is used as an internal electron donor (CN: ZL998006 5.5) to prepare a catalyst component, which promotes the catalyst. The development of the system also makes the research of the internal electron donor of the catalyst component a hot spot. 1,3-diether, such as 9,9-bis(methoxymethyl)anthracene, as a catalyst component for the polymerization of olefins in internal electron donors, having a low polymerization temperature and high catalytic activity, polyalphaolefins The isotacticity (percentage of xylene insoluble matter, the percentage of n-hexane insoluble matter in the present invention) is high, and even when other external donors are not required, the isotacticity of the poly-α-olefin is also high. 9,9-bis(methoxymethyl)anthracene can also be used as an external electron donor. However, the 1,3-diether alone as a catalyst for internal electron donors catalyzes the polymerization of olefins to obtain a narrow molecular weight distribution of polyolefins, which limits the application of polyolefins. An olefin polymerization catalyst having a balance of properties was obtained by combining a general-purpose di-n-butyl phthalate and a 1,3-diether as an internal electron donor. The external electron donor which controls the isotacticity of the poly-α-olefin and adjusts the activity of the catalyst also develops from the ester compound into a hydrocarbyl alkoxysilane of the fourth-generation Z-N catalyst. Hydrocarbon-based alkoxysilanes with different structures control the isotacticity of poly-α-olefins, and thus control the mechanical properties of poly-α-olefin materials, which are quite different. Dicyclopentyldimethoxysilane can well control the isotacticity of polyalphaolefins. Methylcyclohexyldimethoxysilane is a general external electron donor, and diphenyldimethoxysilane is common. The external electron donor used. However, they control the isotacticity of polyalphaolefins, the mechanical properties of the materials, the environmental impact, and the price are very different. Composite external electron donors may be effective in solving these problems.

The temperature control of the polymerization reaction is very important. Exceeding the normal polymerization temperature in the range of 65-70 ° C, the explosion will be triggered, the polymer particles will soften, the bonded joints, the sticky reactors, the blocked pipelines, and even the forced parking accident. At the abnormal polymerization temperature, the isotacticity of the poly-α-olefin is also changed, and even the produced polymer is "waste". This process of continuous polymerization is a huge "risk." The control of the fluidized bed reaction of α-olefin polymerization, the control of the polymerization temperature, and the isotacticity of the poly-α-olefin are more important. Since the polymerization or copolymerization of the α-olefin is a violent exothermic reaction, the polymerization or copolymerization rate of the α-olefin is a key factor in the control of the polymerization temperature.

Summary of the invention

The object of the present invention is to develop a novel dual-functional composite external electron donor body, which can automatically reduce the activity of the catalyst at an abnormal polymerization temperature, change the polymerization reaction rate, rapidly drop the temperature to the normal polymerization temperature, and achieve stable control of the reaction temperature. To prevent the occurrence of explosion accidents. At the same time, even when the abnormal polymerization temperature is temporarily shortened, the properties such as the isotacticity and the melt index of the poly-α-olefin are maintained, and the main technical indexes such as the mechanics and processability of the poly-α-olefin material are maintained. There are many types of hydrocarbyl alkoxysilanes constituting an external electron donor. Different structures of hydrocarbyl alkoxysilanes have different effects on the properties of polyalphaolefins. Hydrocarbon-based hydroxysiloxanes with different structures can be used as external electron donors. Modulate the properties of polyalphaolefins.

The main content of the invention is to improve the performance of the α-olefin polymerized ZN catalyst, develop a bifunctional external electron donor, and develop a composite external electron donor capable of self-controlling the polymerization activity while maintaining various properties of the material. Further, it constitutes a catalyst system which stably controls the industrial large-scale preparation of the poly-α-olefin reaction temperature and can ensure the material properties at an abnormal polymerization temperature. The ZN catalyst is composed of three components (A), (B) and (C), namely: catalyst component A, cocatalyst alkyl aluminum B and autoregulation catalyst activity, and control of polyalphaolefin performance Functional composite external electron donor C; where:

(1) The catalyst component A is composed of at least a transition element such as titanium (ion) supported by magnesium chloride, and a composite internal electron donor; the composite internal electron donor includes a dialkyl aryl dicarboxylate and a 1,3-diether. There are many methods for preparing the catalyst component A, and various transition metal compounds used, added, and produced are also various. The present invention has no limitation on the preparation method, the raw materials used, and the type and amount of the transition metal compound formed, and there is no limitation on the inert transition metal compound added during the preparation. Roughly speaking, the catalyst component A can be prepared by: 1 magnesium chloride alcoholate, composite internal electron donor and titanium tetrachloride coprecipitation method; 2 spherical magnesium chloride alcoholate carrier supported titanium tetrachloride and composite internal electron donor method Preparation; 3 diethoxy magnesium, titanium tetrachloride reaction formed by magnesium chloride supported composite internal electron donor method. These are common methods for the preparation of catalyst component A.

(2) The cocatalyst aluminum alkyl B is at least one of aluminum alkyls. Commonly used are triethyl aluminum, triisobutyl aluminum, dialkyl aluminum hydride, alkyl dihydrogen aluminum, dialkyl aluminum halide, alkyl aluminum dihalide, dialkyl alkoxy aluminum, alkyl two Aluminum alkoxide. The cocatalyst is a C _1-4 trialkyl aluminum, and more and more important is triethyl aluminum.

(3) The dual-functional novel composite external electron donor C includes a composite external electron donor and a polymerization temperature control agent, and the combination of the external external electron donor and the polymerization temperature control agent automatically adjusts the activity of the catalyst and maintains the basic function of the polymer. External electron donor. According to the kind and content of the two internal electron donors in the catalyst component A, the type and amount of the composite external electron donor and the polymerization temperature control agent are selected to satisfy the polymerization activity of the catalyst at the abnormal polymerization temperature, which is smaller than the normal polymerization temperature. The activity satisfies the requirements of the isotacticity of the poly-α-olefin, the melt index, and the like at a normal polymerization temperature. In the novel dual-functional composite external electron donor C, the composite external electron donor includes two external electron donors, and the first external electron donor is two hydrocarbon-based dihydrocarbyl silicon oxides, and the second The extraterrestrial electron donor is a dihydrocarbyldihydrocarbyl silicon, a hydrocarbyl trihydrocarbyl silicon or a tetrahydrocarbyl silicon having two different hydrocarbyl groups, the first external electron donor and the second external electron donor. The molar ratio is 1:9 to 9:1;

The molar ratio of the number of moles of the bifunctional composite external electron donor C to the metal titanium ion in the catalyst component A is from 1 to 500:1;

The molar ratio of the total number of moles of the bifunctional composite external electron donor C to the aluminum compound in the cocatalyst component B is from 0.01 to 5:1.

The composite external electron donor and the polymerization temperature control agent can well achieve the polymerization activity of the catalyst at an abnormal polymerization temperature less than the normal polymerization temperature, and maintain the isotacticity and melt index of the poly-α-olefin, especially It can satisfy and control the performance of poly-α-olefins.

The composite external electron donor is composed of at least two hydrocarbyl alkoxysilanes. For convenience of description, the composite external electron donor is generally classified into a first external electron donor and a second external electron donor. The first external electron donor is R _n Si(OCH ₃ ) _(4-n) or R _n Si(OCH ₂ CH ₃ ) _(4-n) , n=2, and two hydrocarbon groups R ¹ and R ² Is the same; the second external electron donor is a member of R _n Si(OCH ₃ ) _(4-n) or R _n Si(OCH ₂ CH ₃ ) _(4-n) except for the first external electron donor This division is relative. The principle of component selection of the composite external electron donor depends on the properties of the polyalphaolefin to be prepared, i.e., the composite internal electron donor depending on the composition of the catalyst A.

The ZN catalyst according to the above technical solution, wherein the external electron donor is selected from a hydrocarbon-based alkoxy silicon external electron donor generally selected from the ZN fourth-generation catalyst, and controls the structure of the poly-α-ene. Commonly used external electron donors are hydrocarbyl methoxysilane R _n Si(OCH ₃ ) _(4-n) or hydrocarbyl ethoxysilane R _n Si(OCH ₂ CH ₃ ) _(4-n) , generally n=0, 1 or 2. When n = 0, the hydrocarbyl alkoxy silicon is tetramethoxysilane and tetraethoxysilane, and can be used as a second external electron donor. When n=1, the hydrocarbyl alkoxy silicon is a hydrocarbyl trimethoxy silicon and a hydrocarbyl triethoxy silicon, which can be used as a second external electron donor; R is a C _1-18 linear or branched alkyl group, C _5-10 cycloalkyl, alkylcycloalkyl or cycloalkylalkyl, C _6-10 phenyl, phenylalkyl or alkylphenyl. When n=2, R is two hydrocarbon groups R ¹ and R ² , and R ¹ and R ² may be the same or different. When R ¹ and R ² are the same, they are the first external electron donor, and R ¹ and R ^{2 are} not. Also a second external electron donor, R ¹ and/or R ² is a C _1-18 linear or branched alkyl group, a C _5-10 cycloalkyl group, an alkylcycloalkyl group or a cycloalkylalkyl group, C _6-10 phenyl, phenylalkyl or alkylphenyl. Two or more of the external electron donors constitute a composite external electron donor. The conventional composite external electron donor is preferably composed of an external electron donor for a propylene industrial polymerization catalyst.

Preferably, the first external electron donor is dimethyldimethoxysilane, dimethyldiethoxysilane, diethyldimethoxysilane, diethyldiethoxysilane, dipropyl. Dimethoxysilane, dipropyldiethoxysilane, diisopropyldimethoxysilane, diisopropyldiethoxysilane, dibutyldimethoxysilane, dibutyldiethoxy Silicon, diisobutyldimethoxysilane, diisobutyldiethoxysilane, dipentyldimethoxysilane, dipentyldiethoxysilane, diisoamyldimethoxysilane , diisoamyldiethoxysilane, dihexyldimethoxysilane, dihexyldiethoxysilane, dicyclopentyldimethoxysilane, dicyclopentyldiethoxysilane, bicyclo Dimethoxysilane, dicyclohexyldiethoxysilane, diphenyldimethoxysilane, diphenyldiethoxysilane.

Preferably, the second external electron donor is selected from the group consisting of propyltrimethoxysilane, propyltriethoxysilane, butyltrimethoxysilane, butyltriethoxysilane, pentyltrimethoxysilane, Pentyl triethoxysilane, isoamyltrimethoxysilane, isoamyltriethoxysilane, octyltrimethoxysilane, octyltriethoxysilane, isooctyltrimethoxysilane, isooctyl Triethoxysilane, decyltrimethoxysilane, methylcyclopentyldimethoxysilane, methylcyclopentyldiethoxysilane, methylcyclohexyldimethoxysilane, methylcyclohexyl Diethoxysilane.

In the ZN catalyst according to the above technical solution, wherein the catalyst component A, the dialkyl aryl dicarboxylate is di-n-(butyl) phthalate; the 1,3-diether is 2. 2-Dialkyl-1,3-dimethoxypropane, of which 9,9-bis(methoxymethyl)anthracene is commonly used, has been developed by the Applicant as an industrial product. A typical composite internal electron donor is composed of di-n-(butyl) phthalate and 9,9-bis(methoxymethyl)anthracene.

As an external electron donor, the use of 1,3-diether, especially 9,9-bis(methoxymethyl)anthracene is also a good choice. Di(perhydroisoquinoline)dimethoxysilane is also an effective external electron donor.

The ZN catalyst according to the above aspect, wherein the polymerization temperature controlling agent is at least one of a fatty acid ester and a fatty diacid diester. The fatty acid ester comprises a C _10-20 linear fatty acid C ₃ -C ₆ linear, branched alkyl ester, and the fatty diacid diester comprises a C _4-16 linear fatty diacid C _2-8 linear chain. , branched dialkyl ester. Branched alkyl esters of linear fatty acids or linear fatty acid dialkyl esters are important. Esters of natural fatty acids, natural fatty diacids are preferred fatty acid esters.

Further, the polymerization temperature control agent is selected from linear C _10-20 fatty acid C _3-6 alkyl ester or a C _4-16 straight-chain fatty acid C ₂ - ₈ dialkyl ester of at least one of the outer configuration to control the polymerization temperature Electronic body C. Important fatty acid esters are isopropyl dodecanoate, isoamyl dodecanoate, isopropyl myristate, isopropyl palmitate, isopropyl octadecate, diethyl adipate, hexane. Di-n-butyl acid ester, diisobutyl adipate, diethyl suberate, di-n-butyl octate, diisobutyl octate, diethyl sebacate, di-n-butyl sebacate Ester, diisobutyl sebacate.

As a polymerization temperature control agent, natural fatty acid glycerides are also a good choice.

The long-chain natural fatty acid ester is a green chemical and is a base material for cosmetics. The retention of the poly-α-olefin in the poly-α-olefin does not affect the application properties of the polymer, and can also function as a plasticizer. Linear fatty diacid diesters are also green chemicals which are themselves plasticizers of polyalphaolefins. The natural fatty acid glyceride is also a green chemical, and its retention in the poly-α-ene does not affect the application properties of the polymer, and can also function as a plasticizer. The raw materials of long-chain natural fatty acid esters and linear fatty diesters are derived from natural resources, convenient, green, simple processing technology, low price, and sufficient market supply.

For the ZN catalyst described in the above technical solution, specifically, in the catalyst component A, magnesium chloride is used as a carrier, the mass fraction of supported titanium is 2.0-3.8%, and the mass fraction of 1,3-diether is 1-13. %, the mass fraction of the dialkyl aryl dicarboxylate is 1-8%. The types and amounts of other transition metal compounds are not limited.

For the ZN catalyst described in the above technical solution, specifically, the molar ratio of the number of moles of the bifunctional composite external electron donor C to the metal titanium ion (Ti) in the catalyst component A is from 1 to 500:1, preferably 1 ~100:1.

For the ZN catalyst described in the above technical solution, specifically, the molar ratio of the di-n-(butyl) phthalate to the 9,9-bis(methoxymethyl) fluorene is from 1 to 10:10. 1.

In the Z-N catalyst according to the above aspect, specifically, the molar ratio of the total amount of the composite external electron donor to the polymerization temperature controlling agent is from 1 to 10:10.

For the ZN catalyst described in the above technical solution, specifically, the molar ratio of the first external electron donor to the second external electron donor of the two external electron donors of the composite external electron donor is 1 : 9 to 9:1.

The polymerization temperature control agent fatty acid ester and the fatty diacid diester are combined with the composite external electron donor to form an external electron donor. As the polymerization temperature increases, the polymerization activity decreases, and the polymerization activity at the abnormal polymerization temperature is smaller than that in the normal polymerization. 30-40% of the activity of the temperature is even less than 50% of its activity at normal polymerization temperatures. Therefore, the present invention selects a fatty acid ester and a fatty diacid diester as a polymerization temperature controlling agent, and the effect of automatically controlling the polymerization rate is remarkable. At an abnormal polymerization temperature, it has an automatic control of the polymerization rate, that is, the polymerization temperature is rapidly lowered back to the normal polymerization temperature. At normal polymerization temperatures, the polymerization activity may also be lower than that of a catalyst having only a composite external electron donor. This is a highlight of the present invention.

The bifunctional novel composite external electron donor C may contain only a polymerization temperature controlling agent, a fatty acid ester or a fatty diacid, when the specific content of the two internal electron donors in the catalyst component A and the specific performance of the catalyst are required. ester. For example, a general-purpose polypropylene film material having a degree of compliance of 95% is a qualified material. At this time, for some of the catalyst component A having a higher content of 9,9-bis(methoxymethyl)phosphonium, only the fatty acid ester is used as an external electron donor, and the isotactic 95% polypropylene can be obtained. At the same time, the polymerization temperature can be adjusted automatically. This is the second highlight of the invention.

According to the relative contents of the two internal electron donors, it is the third bright spot of the present invention to flexibly select the type and amount of the external electron donor and the polymerization temperature control agent to form an external electron donor that automatically controls the activity of the catalyst.

The external electron donor functions as an external electron donor that combines with the polymerization temperature control agent to automatically control the activity of the catalyst, and the structure of the control polymer remains unchanged. The combination of the external electron donor and the polymerization temperature control agent can satisfy the polymerization activity of the catalyst at the abnormal polymerization temperature less than the polymerization activity at the normal polymerization temperature, can achieve the stable control of the polymerization temperature, and can be abnormal. The properties of the polymer at the polymerization temperature remain unchanged, which is the fourth highlight of the present invention.

The combination of different catalyst components A and different external electron donors has different effects on the properties of polyalphaolefins. The external electron donor in the bifunctional external electron donor of the present application includes two kinds, the first external electron donor and the second external electron donor, constitute a composite external electron donor, the composite external electron donor and the polymerization temperature. The interaction between the control agents, on the one hand, causes the catalyst properties to change when the reaction temperature is raised, changes the polymerization rate, causes the temperature to rapidly fall back to the normal polymerization temperature, and on the other hand ensures the formation at an abnormal polymerization temperature. The important properties such as the isotacticity of the poly-α-olefin remain unchanged, that is, the main properties of the poly-α-olefin formed at the normal polymerization temperature and the abnormal polymerization temperature remain unchanged, maintaining the properties of the poly-α-olefin material, which It is the fifth bright spot of the present invention.

The composite external electron donor and the polymerization temperature control agent method of the present application are flexible and convenient, and the composite external electron donor and the polymerization temperature control agent can be simultaneously added to the polymerization system, or can be separately added to the polymerization system.

Generally, the polymerization temperature of propylene is 65-70 ° C, and the abnormal polymerization temperature is 80-120 ° C. The experiment proves that the polymerization activity of propylene is 30% lower than that of 70 ° C at 90 ° C, and propylene at 110 ° C. The polymerization activity is very small, and even some systems have a polymerization activity close to zero. Therefore, the present invention judges the abnormal polymerization temperature of the externally-donating electron donor C of the bifunctional action to be 90 °C.

The ZN catalyst according to any one of the above aspects, which is applied to polymerization and copolymerization of an α-olefin, the application comprising: propylene polymerization, 1-butene polymerization, propylene and ethylene copolymerization, 1-butyl Copolymerization of olefins with ethylene, copolymerization of propylene with 1-butene, and importantly for propylene polymerization, propylene and ethylene copolymerization.

The improved ZN catalyst of the present invention is used for propylene polymerization, and the obtained polypropylene has an isotacticity of 95-99%, depending on the complex internal electron donor di-n-(butyl) butyl phthalate of the solid catalyst component A. A combination of a molar ratio of 9,9-bis(methoxymethyl)anthracene and a bifunctional external electron donor C. When the combination of the internal electron donor ratio and C is determined, the isotacticity of the polypropylene is determined, and even when the polymerization temperature is raised to 90 to 120 ° C, the isotacticity of the polypropylene remains unchanged, and even the normal polymerization temperature is maintained. The isotacticity, melt index, etc. of the produced polypropylene, even if the explosion occurs, the isotacticity and melt index of the produced polypropylene remain substantially unchanged, thereby ensuring the quality of the polypropylene.

According to the molar ratio of the 1,3-diether to the dialkyl aryl dicarboxylate in the catalyst component A, the composite external electron donor hydrocarbyl alkoxy silicon, the polymerization temperature control agent fatty acid ester species, and each other are adjusted. The molar ratio between the two, maintaining the high activity of the catalyst and the stable isotactic stability of the polypropylene.

The polymerization and copolymerization of the α-olefin is a continuous polymerization reaction, particularly a continuous gas phase polymerization reaction, which is carried out in one or more reactors connected in series; the continuous polymerization is carried out in a fluidized bed reactor.

The bifunctional external electron donor of the invention of the present application is suitable for various polymerization and copolymerization processes of α-olefins, and is particularly suitable for continuous polymerization, especially continuous gas phase polymerization, and is suitable for continuous polymerization and copolymerization of α-olefins. It is carried out in more than one reactor operated in series, in particular in a fluidized bed reactor.

The composite external electron donor and the polymerization temperature controlling agent of the present invention are introduced into the reactor by various methods: the composite external electron donor and the polymerization temperature controlling agent are simultaneously or separately with the catalyst component A and/or the cocatalyst component B simultaneously Adding to the reactor; in one or more reactor processes in series, the external electron donor and the polymerization temperature controlling agent are simultaneously added to the first reactor simultaneously with the catalyst component A and the promoter component B, or the external electron donor may be added first. In the first reactor, the polymerization temperature control agent is then added to a different reactor.

Beneficial effect

(1) adjusting the ratio of the composite external electron donor two kinds of hydrocarbyl alkoxy silicon, the polymerization temperature controlling agent fatty acid ester, etc. according to the molar ratio of the 1,3-diether to the dialkyl aryl dicarboxylate in the catalyst component A The type, the molar ratio between each other, maintaining the high activity of the catalyst and the iso-degree of the poly-α-ene 95-99.9% adjustment operation, expand the application range of the formation of poly-α-olefin.

(2) The catalytic activity of the addition polymerization temperature controlling agent can be higher than that of the catalyst using the external electron donor alone, and the range of selection of the two external electron donors of the catalyst is expanded.

(3) The isotacticity, melt index, and the like of the poly-α-ene obtained by polymerization of propylene using the catalyst system at different temperatures remain unchanged. The quality of the polyalpha-ene is guaranteed throughout the polymerization process, including at abnormal polymerization temperatures.

(4) The catalyst system of the bifunctional external electron donor of the invention of the present invention has achieved good effects in the industrial mobile stirred tank polymerization process and in the gas phase fluidized bed polymerization process to prevent the occurrence of explosion.

(5) The dual-function external electron donor of the present application uses a composite external electron donor and a polymerization temperature control agent to synergistically control the relationship between the reaction activity and the reaction temperature; the external electron donor of different structures— - Hydrocarbyl alkoxy silicon gives different properties to poly-α-olefins, and the external electron donors of the two structures are used in combination, giving the poly-α-olefins the complementary properties of two external electron donors, and more importantly, the poly-α-olefins. The material will have new properties.

(6) The bifunctional external electron donor C of the present application includes a composite external electron donor to significantly improve the mechanical properties of the poly-α-olefin material, improve the processing property of the poly-α-olefin material, and broaden the use of the poly-α-olefin.

Detailed ways

The following non-limiting examples are illustrative of the combination and nature of the composite external electron donor and polymerization temperature control agent suitable for the present catalyst system, to facilitate a more complete understanding of the present invention by those of ordinary skill in the art, but The examples are in no way intended to limit the invention.

Various external electron donors and polymerization temperature control agents supplied by the market are designed and composed of a plurality of composite external electron donor/polymerization temperature control agent combinations, and each combination group is respectively formulated into a 10% hexane solution to ensure each test. Repeatability. The experiment was carried out by bulk polymerization of propylene in a 5 L autoclave. Each experiment was subjected to the following procedure, and an experiment was conducted in which only a composite external electron donor or a composite external electron donor/polymerization temperature control agent was combined. The amount of polypropylene formed before the polymerization temperature was first obtained in each experiment. The polymerization kettle was heated at a constant rate. When the polymerization temperature was reached, the propylene in the reaction vessel was immediately emptied, and the dried polypropylene was weighed. Then, the polymerization experiment is carried out, the polymerization kettle is heated at a constant rate, and when the polymerization temperature is reached, the recording time is started. After the reaction for 1 hour, the propylene in the reaction vessel is immediately emptied, and the dried polypropylene is weighed. When the activity of the catalyst is calculated, the polypropylene is formed before the polymerization temperature is reached. The amount. The pressure of the reactor before the polymerization was stopped was the saturated vapor pressure of propylene at the polymerization temperature. Each test was taken three times and averaged. Retain polymer samples and test other performance data.

The catalyst activity of the present application is the average of multiple calibrations, referred to as standard catalytic activity.

Example

Take 0.02 g of catalyst A component, 1.5 ml of cocatalyst triethylaluminum, the first external electron donor C, the second external electron donor D and the polymerization temperature control agent B, and design different combinations. The experimental results are as follows. Table 1.

Comparative example

In the same manner, 0.02 g of the catalyst A component, 1.5 ml of the promoter triethylaluminum, the external electron donor C, and the polymerization temperature controlling agent B were designed in different combinations, and the experimental results are shown in Table 2.

The Z-N catalyst catalyzes the normal polymerization temperature of the α-olefin at 65-70 ° C, and the polymerization reaction is a strong exothermic reaction. The bifunctional external electron donor C of the present application can effectively control the polymerization reaction rate, that is, stably control the polymerization reaction temperature. When the reaction temperature reached 90 ° C, the polymerization activity was lower than the polymerization activity at 70 ° C by 30% or more. Even in the event of a bursting accident in the production process, the polymerization temperature is hard to exceed 90 °C.

The Ziegler-Natta catalyst of the bifunctional external electron donor of the invention can effectively control the polymerization temperature at 70-120 ° C, and can maintain the isotacticity of the poly-α-olefin and the melt index is stable. Generally, the performance of the catalyst at 20 ° C (70-90 ° C) above the normal temperature is an important evaluation index, and the polymerization temperature is too high than the normal temperature, and the evaluation of the performance of the catalyst is of little significance. Therefore, the present invention focuses on the performance of the catalyst at 70-90 °C.

As can be seen from Table 1, in the polymerization method of the present application, when the polymerization reaction temperature exceeds the normal polymerization temperature, the activity of the catalyst can be effectively controlled automatically, so that the polymerization reaction rate is lowered, and the temperature rapidly falls back to the normal polymerization temperature. At the same time, the polymerization temperature increases, the isotacticity of the product remains unchanged, and the melt index is stable.

It can also be seen from Table 1 that in the polymerization method of the present application, the isotacticity of the produced poly-α-olefin is arbitrarily adjusted from 95 to 99% while maintaining good melt index performance; the isotacticity and melt index of the product are The larger range has been adjusted to broaden the use of polyalphaolefins.

It can be seen from Table 2 that as the reaction temperature increases, the activity of the catalyst can be automatically controlled, so that the polymerization activity is lowered, which is favorable for the temperature to fall back to the normal polymerization temperature. However, as the temperature increases, there is no stable rule for the isotacticity and melt index of the product. Once the production process bursts, the performance of the obtained poly-α-olefin is difficult to guarantee, and even a batch of waste products is produced. This is a huge threat to the continuous polymerization process.

This shows that the composite external electron donor has an excellent effect on controlling the isotacticity and melt index of the product.

Table 1

Note: A catalyst component, A ₁ magnesium chloride alcoholate, composite internal electron donor and titanium tetrachloride coprecipitation method, including titanium 2.78%, diisobutyl phthalate 1.71%, 9, 9- Bis(methoxymethyl)phosphonium 5.31%; A ₂ spherical magnesium chloride alcoholate carrier supported by titanium tetrachloride and composite internal electron donor, wherein titanium is 3.01%, diisobutyl phthalate 3.07%, 9,9-bis (methoxymethyl) fluorene 5.14%; a ₃ diethoxy magnesium, titanium tetrachloride generated within the reaction to magnesium chloride-supported method of an electron donor compound prepared in which 2.73% titanium, phthalic acid Di-n-butyl ester 9.20%, 9,9-bis(methoxymethyl)anthracene 1.54%. B polymerization temperature control agent, wherein B ₁ isopropyl acid isopropyl ester, B ₂ tetradecanoate isopropyl ester, B ₃ hexadecanoic acid isopropyl ester, B ₄ octadecanoic acid isopropyl ester, B ₅ suberic acid diethyl ester. C. The first external electron donor, wherein C ₁ dimethyl dimethoxy silicon, C ₂ diisopropyl dimethoxy silicon, C ₃ diisobutyl dimethoxy silicon, C ₄ dicyclopentane Silicon dimethoxysilane. D. Second external electron donor, wherein D ₁ propyl trimethoxy silicon, D ₂ propyl triethoxy silicon, D ₃ tetraethoxy silicon, D ₄ methylcyclohexyl dimethoxy silicon, D ₅ 9,9-bis(methoxymethyl)anthracene.

Table 2

Note: A catalyst component: A ₁ magnesium chloride alcoholate, composite internal electron donor and titanium tetrachloride coprecipitation method, including magnesium 17.17%, titanium 2.24%, diisobutyl phthalate, 2.68% 9,9-bis(methoxymethyl)anthracene 12.14%; A ₂ spherical magnesium chloride alcoholate carrier is prepared by a method of supporting titanium tetrachloride and a composite internal electron donor, which contains 18.23% of magnesium and 3.11% of titanium, adjacent to Preparation of diisobutyl phthalate 6.07%, 9,9-bis(methoxymethyl)anthracene 5.14%; preparation of magnesium chloride supported by internal reaction of electron donor formed by reaction of A ₃ diethoxy magnesium and titanium tetrachloride It contains 18.16% of magnesium, 3.14% of titanium, 5.32% of diisobutyl phthalate, and 11.89% of 9,9-bis(methoxymethyl)anthracene. B polymerization temperature control agent: B ₁ isopropyl tetradecanoate, B ₂ hexadecanoic acid isopropyl ester, B ₃ octadecanoic acid isopropyl ester. C external electron donor: C ₁ diisobutyl dimethoxy silicon, C ₂ methylcyclohexyl dimethoxy silicon, C ₃ propyl trimethoxy silicon. Experimental parameters: the molar ratio of external electron donor to titanium is 20; the mass ratio of external electron donor to B polymerization temperature control agent is 20:80.

Claims

A Z-N catalyst for preparing a poly-α-olefin, comprising: a catalyst component A supporting an internal electron donor by magnesium chloride, a cocatalyst alkyl aluminum B, and a bifunctional external electron donor C; wherein:

(1) The catalyst component A is at least composed of magnesium chloride-supported titanium ions and a composite internal electron donor; the composite internal electron donor comprises a dialkyl aryl dicarboxylate and a 1,3-diether;

(2) the promoter aluminum alkyl B is at least one of triethyl aluminum and triisobutyl aluminum;

(3) The external electron donor C having a dual function includes a composite external electron donor and a polymerization temperature controlling agent, and the polymerization temperature controlling agent is at least one of a fatty acid ester and a fatty diacid diester;

In the bifunctional external electron donor C, the composite external electron donor comprises two external electron donors, the first external electron donor is a dihydrocarbyl dihydrocarbyl silicon having the same two hydrocarbyl groups, and the second The external electron donor is a dihydrocarbyldihydrocarbyl silicon, a hydrocarbyl trihydrocarbyl silicon or a tetrahydrocarbyl silicon having two different hydrocarbyl groups, and the molars of the first external electron donor and the second external electron donor The ratio is 1:9 to 9:1;

The molar ratio of the bifunctional external electron donor C to the metal titanium ion in the catalyst component A is from 1 to 500:1;

The molar ratio of the bifunctional external electron donor C to the aluminum compound in the cocatalyst component B is from 0.01 to 5:1.
The ZN catalyst according to claim 1, wherein said composite external electron donor is Si(OCH 3 ) 4 , Si(OCH 2 CH 3 ) 4 , R n Si(OCH 3 ) (4-n). ), or R n Si (OCH 2 CH 3 ) (4-n), and n = 1 or 2; when n = 1, R is a C 1-12 linear or branched alkyl; C 5-10 cycloalkyl Alkylcycloalkyl or cycloalkylalkyl; C 6-10 phenyl, phenylalkyl or alkylphenyl; when n=2, R is two hydrocarbyl groups R 1 and R 2 , R 1 And R 2 may be the same or different, and R 1 and/or R 2 are a C 1-12 straight or branched alkyl group; a C 5-10 cycloalkyl group, an alkylcycloalkyl group or a cycloalkylalkyl group; 6-10 phenyl, phenylalkyl or alkylphenyl.
The ZN catalyst according to claim 1 or 2, wherein the first external electron donor is dimethyldimethoxysilane, dimethyldiethoxysilane, diethyldimethoxysilane. Silicon, diethyldiethoxysilane, dipropyldimethoxysilane, dipropyldiethoxysilane, diisopropyldimethoxysilane, diisopropyldiethoxysilane, Dibutyldimethoxysilane, dibutyldiethoxysilane, diisobutyldimethoxysilane, diisobutyldiethoxysilane, diisoamyldimethoxysilane, diiso Pentyldiethoxysilane, dicyclopentyldimethoxysilane, dicyclopentyldiethoxysilane, dicyclohexyldimethoxysilane, dicyclohexyldiethoxysilane, diphenyl Dimethoxysilane, diphenyldiethoxysilane, bis(perhydroisoquinoline)dimethoxysilane;

The second external electron donor is propyltrimethoxysilane, propyltriethoxysilane, butyltrimethoxysilane, butyltriethoxysilane, pentyltrimethoxysilane, pentyltriethoxysilane. Silicon, isoamyltrimethoxysilane, isoamyltriethoxysilane, octyltrimethoxysilane, octyltriethoxysilane, isooctyltrimethoxysilane, isooctyltriethoxy Silicon, mercaptotrimethoxysilane, mercaptotriethoxysilane, methylcyclopentyldimethoxysilane, methylcyclopentyldiethoxysilane, methylcyclohexyldimethoxysilane or Cyclohexyldiethoxysilane.
The ZN catalyst according to claim 1, wherein the polymerization temperature controlling agent is at least one of a fatty acid ester and a fatty diacid diester, and comprises a C 10-20 linear fatty acid C 3-6 linear chain. , branched alkyl ester, C 4-16 linear fatty diacid C 2-6 linear, branched dialkyl ester.
The ZN catalyst according to claim 4, wherein the polymerization temperature controlling agent is an ester of a natural fatty acid, including propyl laurate, isopropyl dodecylate, amyl dodecanoate, and dodecanoic acid. Isoamyl ester, propyl myristate, isopropyl myristate, isoamyl myristate, propyl palmitate, isopropyl palmitate, propyl octadecate, isopropyl octadecanoate; Adipic diacid diester is selected from diethyl dicarboxylate, di-n-butyl adipate, di-isobutyl adipate, diethyl suberate, di-n-butyl octate, diisobutyl octanoate Ester, diethyl sebacate, di-n-butyl sebacate, diisobutyl sebacate.
The ZN catalyst according to claim 1, wherein in the catalyst component A, magnesium chloride is used as a carrier, the mass fraction of supported titanium is 2.0-3.8%, and the mass fraction of 1,3-diether is 1-13. %, the mass fraction of the dialkyl aryl dicarboxylate is 1-8%; in the catalyst component A, the dialkyl aryl dicarboxylate is di-n-(butyl) phthalate; The diether is 9,9-bis(methoxymethyl)anthracene; the complex internal electron donor is di-n-(butyl) phthalate and 9,9-bis(methoxymethyl)anthracene; The molar ratio of di-n-butyl phthalate to 9,9-bis(methoxymethyl) hydrazine is from 1 to 10:10 to 1.
The Z-N catalyst according to claim 1, wherein the molar ratio of the composite external electron donor to the polymerization temperature controlling agent is from 1 to 10:10.
The ZN catalyst for preparing a poly-α-olefin according to claim 1, wherein the preparation of the poly-α-olefin comprises: propylene polymerization, 1-butene polymerization, ethylene and propylene copolymerization. The reaction, ethylene and 1-butene copolymerization, propylene and 1-butene copolymerization.
The use of the ZN catalyst according to any one of claims 1 or 8 for the preparation of a poly-α-olefin, characterized in that the polymerization and copolymerization of the α-olefin are continuous polymerization or continuous gas phase polymerization, The reactor for continuous polymerization is one or more reactors in series, and the reactor for continuous polymerization is a fluidized bed reactor; the reactor for continuous gas phase polymerization is one or more reactors in series, and the reaction of continuous gas phase polymerization The reactor is a fluidized bed reactor.
The use according to claim 9, wherein in the polymerization and copolymerization of the α-olefin, the composite external electron donor and the polymerization temperature controlling agent are introduced into the reactor by various methods: composite external electron donor and The polymerization temperature controlling agent is added to the reactor together or separately with the catalyst component A and/or the cocatalyst component B; in the reactor process of one or more reactors in series, the composite external electron donor and the polymerization temperature controlling agent are respectively combined with the catalyst component A. The cocatalyst component B is simultaneously added to the first reactor, or the composite external electron donor may be first added to the first reactor, and the polymerization temperature controlling agent is subsequently added to the different reactor.