CN110511303B

CN110511303B - Catalyst component for olefin polymerization and catalyst thereof

Info

Publication number: CN110511303B
Application number: CN201810489139.5A
Authority: CN
Inventors: 张锐; 谭忠; 周奇龙; 徐秀东; 李凤奎; 尹珊珊; 于金华; 宋维玮
Original assignee: Sinopec Beijing Research Institute of Chemical Industry; China Petroleum and Chemical Corp
Current assignee: Sinopec Beijing Research Institute of Chemical Industry; China Petroleum and Chemical Corp
Priority date: 2018-05-21
Filing date: 2018-05-21
Publication date: 2020-12-18
Anticipated expiration: 2038-05-21
Also published as: CN110511303A

Abstract

The invention relates to a catalyst component for olefin polymerization and a catalyst thereof. The catalyst component comprises magnesium, titanium, halogen, an internal electron donor compound and a precipitation aid, wherein the precipitation aid comprises a precipitation aid a shown in a general formula (I); the auxiliary precipitating agent a shown in the general formula (I) comprises optical isomers shown in the general formula (I-a) and/or the general formula (I-b), and the content of the optical isomers shown in the general formula (I-a) and/or the general formula (I-b) is more than 90 wt%. When the catalyst is used for olefin polymerization reaction, the catalyst has high activity, good hydrogen regulation sensitivity and high copolymerization capacity, and is particularly suitable for preparing impact-resistant copolymerized polypropylene.

Description

Catalyst component for olefin polymerization and catalyst thereof

Technical Field

The invention belongs to the technical field of catalysts, and particularly relates to a catalyst component for olefin polymerization and a catalyst thereof.

Background

The polypropylene is one of five synthetic resins in the world, has the characteristics of low price, good processing performance, low density, excellent chemical corrosion resistance and mechanical property and the like, and is widely applied. However, the impact resistance (toughness) of the homo-polypropylene is poor at low temperature, which severely limits the further application of the homo-polypropylene in various fields.

At present, two main methods for toughening and modifying polypropylene are as follows: mechanically blended with an elastomer and copolymerized with a certain amount of ethylene to produce an impact copolymer polypropylene. Because the compatibility between polypropylene and the elastomer is poor, the elastomer is difficult to be uniformly distributed in the polypropylene matrix by mechanical blending, the size of a dispersed phase is large, and the toughening effect of the material is not obvious. It is an efficient and economical practice to copolymerize with ethylene to produce impact co-polypropylene, which is typically a heterogeneous mixture of polypropylene produced in several reactors connected in series, the homopolymerization of propylene in the first reactor to produce a propylene homopolymer which is then fed to the next reactor and copolymerized with monomers of propylene and ethylene or other olefins to produce a polymer based on an ethylene-propylene random copolymer in the pores of the propylene homopolymer. The impact-resistant co-polypropylene finally obtained has good rigidity-toughness balance and is widely applied.

The ethylene content and distribution in the impact polypropylene determines its impact properties. The ethylene content depends mainly on the copolymerizability of the catalyst used for the polymerization and on the polymerization process conditions. The stronger the later activity of the catalyst, i.e. the slower the activity decay, the more beneficial to the improvement of the ethylene content; in addition, in the case of the same concentration of the di-trans ethylene, the ethylene content in the rubber phase is higher, and the copolymerization ability of the catalyst is better. In other words, the lower the concentration of ethylene in the rubber phase required to achieve the same ethylene content in the copolymerisation catalyst, the more beneficial the removal of the heat of reaction in the second reactor. Therefore, how to improve the copolymerization ability of the catalyst becomes a hot research focus for preparing impact-resistant copolymerized polypropylene.

CN101864009 discloses a catalyst using diol ester as a precipitation aid and a preparation method thereof, wherein the content of diol ester in the catalyst is 3-5%. The catalyst has excellent comprehensive performances such as particle morphology, activity, orientation capability and the like, but the copolymerization capability of the catalyst is lacked when the catalyst is actually applied to the production process of the impact copolymer.

Therefore, there is a problem that research and development of a catalyst component for olefin polymerization and a catalyst thereof, which have high activity, strong orientation ability, good hydrogen response and high catalyst copolymerization ability, are urgently needed.

Disclosure of Invention

The technical problem to be solved by the present invention is to provide a catalyst component for olefin polymerization and a catalyst thereof, aiming at the defects of the prior art. The inventor of the invention carries out extensive and intensive experimental research in the technical field of olefin polymerization catalysts, and adopts glycol ester with the content of isomer (R, R-configuration and/or S, S-configuration isomer) with a specific optical configuration being more than 95 percent as a precipitation aid a, so that the precipitation aid a has good precipitation effect, the obtained catalyst has good particle shape, and the content of the precipitation aid is extremely low; when the catalyst is used for preparing the impact copolymer, the catalyst has high activity, strong orientation capability and good hydrogen regulation sensitivity, and the copolymerization capability of the catalyst is greatly improved.

To this end, the present invention provides in a first aspect a catalyst component for olefin polymerization comprising magnesium, titanium, a halogen, a precipitation aid and an internal electron donor compound, wherein the precipitation aid comprises a precipitation aid a represented by the general formula (I);

wherein R is₁And R₂Same or different, each independently selected from substituted or unsubstituted C₁-C₁₀Alkyl of (C)₃-C₁₀Cycloalkyl of, C₆-C₁₀Aryl or C of₇-C₁₀Aralkyl of (2), preferably R₁And R₂Each independently selected from substituted or unsubstituted C₁-C₈Alkyl of (C)₃-C₈Cycloalkyl or C₆-C₈More preferably R₁And R₂Each independently selected from substituted or unsubstituted C₁-C₄Further preferably R₁And R₂Each independently selected from methyl, ethyl, n-propyl or isopropyl; r₃And R₄Same or different, each independently selected from substituted or unsubstituted C₁-C₂₀Alkyl of (C)₃-C₂₀Cycloalkyl of, C₆-C₂₀Aryl or C of₇-C₂₀Aralkyl of (2), preferably R₃And R₄Each independently selected from substituted or unsubstituted C₁-C₁₀Alkyl of (C)₃-C₁₀Cycloalkyl or C₆-C₁₀More preferably R₃And R₄Each independently selected from substituted or unsubstituted C₅-C₁₀Alkyl, cycloalkyl, aryl or aralkyl of (2), further preferably R₃And R₄Each independently selected from cyclopentyl, cyclohexyl, phenyl, p-methylphenyl, p-ethylphenyl, p-n-propylphenyl, p-n-butylphenyl.

The auxiliary precipitating agent a shown in the general formula (I) comprises optical isomers shown in the general formula (I-a) and/or the general formula (I-b), and the content of the optical isomers shown in the general formula (I-a) and/or the general formula (I-b) is more than 90 wt%, preferably more than 95 wt%, and more preferably more than 98 wt%;

the "substitution" in the present invention means that hydrogen on each group is substituted with a halogen (hetero) atom, an alkyl group or an alkoxy group; the carbon atoms in the main chain are replaced by heteroatoms.

The precipitation assistant a shown in the general formula (I) in the invention is a diol ester compound which contains two chiral carbon atoms when R is₁And R₂Not identical and/or R₃And R₄When the two chiral carbon atoms are different, the two chiral carbon atoms are different chiral carbon atoms, the compound shown in the general formula (I) comprises four optical isomers of R, R-configuration, S-configuration, R, S-configuration and S, R-configuration shown in the general formulas (I-a), (I-b), (I-c) and (I-d), wherein the R, R-configuration and the S, S-configuration, the R, S-configuration and the S, R-configuration are enantiomers respectively, and the R, R-configuration and the R, S-configuration or the S, R-configuration, the S, S-configuration and the R, S-configuration or the S, R-configuration are called diastereoisomers; when R is₁And R₂Are identical and R₃And R₄And meanwhile, the two chiral carbon atoms are the same chiral carbon atoms, the R, S-configuration and the S, R-configuration are completely the same configuration, the R, R-configuration and the S, S-configuration are not influenced and still are enantiomers, and simultaneously, the R, S-configuration and the S, S-configuration are still diastereoisomers, and the compound shown in the general formula (I) only has three optical isomers.

Examples of suitable enantiomeric combinations of formula (I-a) and formula (I-b) according to the catalyst components of the present invention include, but are not limited to:

(R, R) -2, 4-pentanediol dibenzoate and (S, S) -2, 4-pentanediol dibenzoate, (R, R) -2, 4-pentanediol di-p-methylbenzoate and (S, S) -2, 4-pentanediol di-p-methylbenzoate, (R, R) -2, 4-pentanediol di-p-ethylbenzoate and (S, S) -2, 4-pentanediol di-p-ethylbenzoate, (R, R) -2, 4-pentanediol di-p-n-propylbenzoate and (S, S) -2, 4-pentanediol di-p-n-propylbenzoate, (R, R) -2, 4-pentanediol di-p-n-butylbenzoate and (S, S) -2, 4-pentanediol di-p-n-butylbenzoate, and, (R, R) -3, 5-heptanediol dibenzoate and (S, S) -3, 5-heptanediol dibenzoate, (R, R) -3, 5-heptanediol di-p-methylbenzoate and (S, S) -3, 5-heptanediol di-p-methylbenzoate, (R, R) -3, 5-heptanediol di-p-ethylbenzoate and (S, S) -3, 5-heptanediol di-p-ethylbenzoate, one or more groups of enantiomeric combinations of (R, R) -3, 5-heptanediol di-p-n-propylbenzoate and (S, S) -3, 5-heptanediol di-p-n-propylbenzoate, and (R, R) -3, 5-heptanediol di-p-n-butylbenzoate and (S, S) -3, 5-heptanediol di-p-n-butylbenzoate.

Preferably selected from the group consisting of (R, R) -2, 4-pentanediol dibenzoate and (S, S) -2, 4-pentanediol dibenzoate, (R, R) -2, 4-pentanediol di-p-methyl benzoate and (S, S) -2, 4-pentanediol di-p-methyl benzoate, (R, R) -2, 4-pentanediol di-p-ethyl benzoate and (S, S) -2, 4-pentanediol di-p-ethyl benzoate, (R, R) -2, 4-pentanediol di-p-n-propyl benzoate and (S, S) -2, 4-pentanediol di-p-n-propyl benzoate, (R, R) -3, 5-heptanediol dibenzoate and (S, S) -3, 5-heptanediol dibenzoate, (R, one or more groups of enantiomeric combinations of R) -3, 5-heptanediol di-p-methylbenzoate and (S, S) -3, 5-heptanediol di-p-methylbenzoate, of (R, R) -3, 5-heptanediol di-p-ethylbenzoate and of (S, S) -3, 5-heptanediol di-p-ethylbenzoate, of (R, R) -3, 5-heptanediol di-p-n-propylbenzoate and of (S, S) -3, 5-heptanediol di-p-n-propylbenzoate.

Most preferably selected from the group consisting of (R, R) -2, 4-pentanediol dibenzoate and (S, S) -2, 4-pentanediol dibenzoate, (R, R) -2, 4-pentanediol di-p-methylbenzoate and (S, S) -2, 4-pentanediol di-p-methylbenzoate, (R, R) -2, 4-pentanediol di-p-ethylbenzoate and (S, S) -2, 4-pentanediol di-p-ethylbenzoate, (R, R) -3, 5-heptanediol dibenzoate and (S, S) -3, 5-heptanediol dibenzoate, (R, R) -3, 5-heptanediol di-p-methylbenzoate and (S, S) -3, 5-heptanediol di-p-methylbenzoate, (R, R) -3, one or more groups of enantiomeric combinations of 5-heptanediol di-p-ethylbenzoate and (S, S) -3, 5-heptanediol di-p-ethylbenzoate.

According to the catalyst component of the present invention, the content of the precipitation aid a is less than 1.0 wt% based on the total weight of the catalyst component.

In some embodiments of the present invention, the content of the precipitant aid a is less than 0.5 wt%, based on the total weight of the catalyst component.

In some preferred embodiments of the present invention, the content of the precipitant aid a is less than 0.2 wt%, based on the total weight of the catalyst component.

In some further preferred embodiments of the present invention, the content of the precipitation aid a is below 0.1 wt. -%, based on the total weight of the catalyst component.

According to the catalyst component of the present invention, the precipitant aid optionally comprises a precipitant aid b represented by the general formula (II);

Ti(OR₇)_nX_4-n(II)

wherein R is₇Is selected from C₁-C₁₀Alkyl or C₃-C₁₀X is halogen, n is more than or equal to 1 and less than or equal to 4, and n is an integer.

In some embodiments of the present invention, the precipitation assistant b is at least one selected from the group consisting of tetramethyl titanate, tetraethyl titanate, tetrabutyl titanate, and tetraisopropyl titanate, preferably tetrabutyl titanate.

The term "optionally" as used herein means either with or without, and with or without the addition of.

According to the catalyst component of the invention, the internal electron donor compound is selected from phthalate compounds shown as a general formula (III);

wherein R is₅And R₆Same or different, each independently selected from substituted or unsubstituted C₁-C₁₀Alkyl of (C)₃-C₁₀Cycloalkyl of, C₆-C₁₀Aryl or C of₇-C₁₀An alkylaryl group of (a); preferably R₅And R₆Each independently selected from substituted or unsubstituted C₁-C₈Alkyl of (C)₃-C₈Cycloalkyl or C₆-C₈Aryl of (a); more preferably R₅And R₆Each independently selected from substituted or unsubstituted C₁-C₆Alkyl groups of (a); further preferably R₅And R₆Each independently selected from methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, n-pentyl, isopentyl.

Examples of suitable phthalate compounds of formula (III) include, but are not limited to:

one or more of dimethyl phthalate, diethyl phthalate, di-n-propyl phthalate, diisopropyl phthalate, di-n-butyl phthalate, diisobutyl phthalate, di-n-pentyl phthalate and diisopentyl phthalate.

Preferably one or more selected from diethyl phthalate, di-n-propyl phthalate, diisopropyl phthalate, di-n-butyl phthalate, diisobutyl phthalate, di-n-pentyl phthalate.

Most preferably one or more selected from the group consisting of diethyl phthalate, diisopropyl phthalate, di-n-butyl phthalate, diisobutyl phthalate.

The catalyst component according to the invention, the titanium content is from 1.0% by weight to 8.0% by weight, preferably from 1.6% by weight to 6.0% by weight, based on the total weight of the catalyst component; the content of the magnesium is 10.0 to 70.0 weight percent, and preferably 15.0 to 40.0 weight percent; the content of the halogen is 20.0-90.0 wt%, preferably 30.0-85.0 wt%; the content of the internal electron donor compound is 2.0 wt% -30.0 wt%, preferably 3.0 wt% -20.0 wt%.

According to the catalyst component provided by the invention, the catalyst component comprises a magnesium compound, a titanium compound, at least one internal electron donor compound shown in a general formula (III) and at least one reaction product of a precipitation assistant a shown in a general formula (I). The amounts of the titanium compound, the magnesium compound and the internal electron donor compound used for preparing the catalyst component are not particularly limited and may be those conventionally used in the art.

In some embodiments of the present invention, the precipitation aid a is used in an amount of 0.005 to 0.3 mole, preferably 0.01 to 0.05 mole, per mole of the magnesium compound; the molar ratio of the precipitation assistant a to the internal electron donor compound is 0.05:1 to less than 0.8:1, preferably (0.1-0.7): 1.

In some embodiments of the present invention, the precipitation aid used for the preparation of the catalyst component further comprises a precipitation aid b, which is used in an amount of 0.01 to 5 moles, preferably 0.5 to 3 moles, per mole of the precipitation aid a.

The preparation method of the olefin polymerization catalyst component of the present invention can be carried out by a method for preparing an olefin catalyst component which is conventional in the art. The catalyst component for olefin polymerization of the present invention can be prepared, for example, by the following method.

The method comprises the following steps of (1) carrying out a first contact reaction on a magnesium compound and an alcohol compound in an inert hydrocarbon solvent to obtain a uniform magnesium compound alcohol compound solution; (2) in the presence of a precipitation assistant, carrying out a second contact reaction on the uniform solution obtained in the step (1) and a first part of titanium compound to obtain a mixture containing solid precipitates; (3) carrying out a third contact reaction on the mixture obtained in the step (2) and the electron donor compound in the first part to obtain a suspension; (4) carrying out solid-liquid separation on the suspension obtained in the step (3), carrying out fourth contact reaction on the obtained solid intermediate product, a second part of titanium compound and an electron donor compound in the second part, and then carrying out solid-liquid separation to obtain a solid intermediate product; (5) and (3) carrying out fifth contact reaction on the solid intermediate product obtained in the step (4) and a third part of titanium compound, carrying out solid-liquid separation, washing the obtained solid product by using an inert solvent, and drying to obtain the final solid catalyst component.

The alcohol compound used in the first method is selected from one or more of aliphatic alcohol, alicyclic alcohol or aromatic alcohol; wherein the fatty alcohol is selected from C₁-C₁₀Straight or branched fatty alcohols of (a); the alicyclic alcohol is selected from C₃-C₁₂The alicyclic alcohol of (1); the aromatic alcohol is selected from C₆-C₂₀Of aryl alcohol or C₇-C₂₀The aralkyl alcohol of (1).

In some embodiments of the invention, the alcohol compound is selected from one or more of ethanol, propanol, butanol, 2-ethylhexanol, benzyl alcohol, phenethyl alcohol, preferably 2-ethylhexanol.

The amount of each component used in the first process is 2 to 4 moles, preferably 2.5 to 3.5 moles, of the alcohol compound per mole of magnesium, and the amount of the titanium compound used in the steps (2), (4) and (5) is 1 to 40 moles, preferably 1.5 to 35 moles.

In method one, the temperature of the first contact reaction is 30 to 150 ℃, preferably 60 to 140 ℃; the time for the first contact reaction is 0.5 to 10 hours, preferably 0.5 to 6 hours. The temperature of the second contact reaction is-40 ℃ to 0 ℃, preferably-30 ℃ to-20 ℃, and the time of the second contact reaction is 3 to 5 hours, preferably 3.5 to 4.5 hours. The temperature of the third contact reaction is 20-120 ℃, and preferably 70-110 ℃; the time for the third contact reaction is 0.5 to 6 hours, preferably 1 to 4 hours. The temperature of the fourth contact reaction is 50-150 ℃, preferably 80-120 ℃; the time for the fourth contact reaction is 1 to 6 hours, preferably 2.5 to 4.5 hours. The temperature of the fifth contact reaction is 50-150 ℃, preferably 80-120 ℃; the time for the five-contact reaction is 1 to 6 hours, preferably 2.5 to 4.5 hours.

Carrying out a first contact reaction on a magnesium compound, an organic epoxy compound and an organic phosphorus compound in an inert hydrocarbon solvent to obtain a uniform magnesium compound solution; (2) in the presence of a precipitation assistant, carrying out a second contact reaction on the uniform solution obtained in the step (1) and a first part of titanium compound and a first part of internal electron donor compound to obtain a suspension containing a solid precipitate; (3) carrying out solid-liquid separation on the suspension containing the solid precipitate obtained in the step (2), carrying out third contact reaction on the obtained solid intermediate product A, a second part of titanium compound and an electron donor compound in the second part, and carrying out solid-liquid separation to obtain a solid intermediate product B; (4) carrying out fourth contact reaction on the solid intermediate product B obtained in the step (3) and a third part of titanium compound, and carrying out solid-liquid separation to obtain a solid intermediate product C; and carrying out contact reaction on the obtained solid intermediate product C and a titanium compound, repeating for 1-3 times, carrying out solid-liquid separation, washing the obtained solid product by using an inert solvent, and drying to obtain the final solid catalyst component.

The organic epoxy compound used in the second process is at least one selected from the group consisting of ethylene oxide, propylene oxide, butylene oxide, butadiene double oxide, epichlorohydrin, methyl glycidyl ether and diglycidyl ether, preferably epichlorohydrin.

The organophosphorus compound used in the second process is selected from hydrocarbyl or halohydrocarbyl esters of orthophosphoric acid or phosphorous acid, preferably at least one of trimethyl orthophosphate, triethyl orthophosphate, tributyl orthophosphate, triphenyl orthophosphate, trimethyl phosphite, triethyl phosphite, tributyl phosphite or benzyl phosphite, more preferably tributyl orthophosphate.

The amount of each component used in the second method is 0.2 to 10 moles, preferably 0.5 to 4.0 moles, of the organic epoxy compound per mole of magnesium; the organic phosphorus compound is used in an amount of 0.1 to 3.0 mol, preferably 0.3 to 1.5 mol; in the steps (2) to (4), the titanium compound is used in an amount of 3 to 40 mol, preferably 5 to 35 mol.

In the second method, the temperature of the first contact reaction is 0 to 80 ℃, preferably 10 to 60 ℃; the time for the first contact reaction is 0.5 to 10 hours, preferably 0.5 to 6 hours. The temperature of the second contact reaction is-40 ℃ to 0 ℃, preferably-30 ℃ to-20 ℃; the time for the second contact reaction is 3 to 5 hours, preferably 3.5 to 4.5 hours. The temperature of the third contact reaction is 50-150 ℃, preferably 80-120 ℃; the time for the third contact reaction is 1 to 6 hours, preferably 2.5 to 4.5 hours. The temperature of the fourth contact reaction is 50-150 ℃, preferably 80-120 ℃; the time for the fourth contact reaction is 1 to 6 hours, preferably 2.5 to 4.5 hours.

According to the catalyst component of the present invention, in the above two preparation methods, the molar ratio of the electron donor compound in the first part to the electron donor compound in the second part is (0.1-10):1, preferably (0.2-5):1, and more preferably (0.2-1): 1.

According to the catalyst component of the present invention, in the above production method, the magnesium compound includes one or more of a compound represented by general formula (IV), a hydrate represented by general formula (V), and an alcoholate represented by general formula (VI);

MgR₈R₉ (IV)

MgR₈R₉·qH₂O (V)

MgR₈R₉·pR₀OH (VI)

in the general formulae (IV) to (VI), R₈And R₉Identical or different, each independently selected from halogen, C₁-C₅A hydrocarbon group, a hydrocarbon oxy group, a halogenated hydrocarbon group or a halogenated hydrocarbon oxy group; preferably R₈And R₉Each halogen, which is fluorine, chlorine, bromine or iodine, preferably chlorine or bromine.

In the formula (V), q is from 0.1 to 6.0, preferably from 2.0 to 3.5;

in the general formula (VI), R₀Is selected from C₁-C₁₈Is preferably C₁-C₅Alkyl groups of (a); p is 0.1 to 6.0, preferably 2.0 to 3.5.

In some preferred embodiments of the present invention, the magnesium compound is selected from at least one of magnesium dichloride, magnesium dibromide, phenoxymagnesium chloride, isopropoxymagnesium chloride, butoxymagnesium chloride.

In some more preferred embodiments of the invention, the magnesium compound is anhydrous magnesium dichloride.

According to the catalyst component of the present invention, in the above preparation method, the inert hydrocarbon solvent may be a hydrocarbon solvent which is not chemically reacted with the magnesium compound and is commonly used in the art, such as at least one of alkane, cycloalkane, or aromatic hydrocarbon, preferably at least one of decane, benzene, toluene, or xylene, and more preferably toluene.

According to the catalyst component of the present invention, in the above preparation method, the titanium compound comprises at least one compound represented by the general formula (VII);

TiX_m(OR₁₀)_4-m (VII)

in the general formula (VII), R₁₀Is C₁-C₂₀Is preferably C₁-C₅Alkyl groups of (a); x is halogen; m is 1. ltoreq. m.ltoreq.4 and m is an integer, such as 1, 2, 3 or 4. The halogen is chlorine, bromine or iodine.

In some preferred embodiments of the present invention, the titanium compound is selected from at least one of titanium tetrachloride, titanium tetrabromide, titanium tetraiodide, tetraalkoxytitanium, alkoxytrihalogenated titanium, dialkoxytitanium dihalide, trialkoxytitanium halide.

In some more preferred embodiments of the invention, the titanium compound is titanium tetrachloride.

In a second aspect, the present invention provides a catalyst for olefin polymerization comprising the following components:

component 1, a catalyst component according to the first aspect of the present invention;

component 2, an alkyl aluminum compound;

and optionally a component 3, an external electron donor compound.

Wherein the molar ratio of component 1 to component 2, calculated as titanium to aluminium, is (5-5000):1, preferably (20-1000):1, more preferably (50-500): 1.

The component 2 alkylaluminum compound according to the catalyst of the present invention may be various alkylaluminum compounds commonly used in the field of olefin polymerization, which can be used as a cocatalyst of a ziegler-natta type catalyst.

In some preferred embodiments of the present invention, the component 2 alkyl aluminum compound comprises at least one compound represented by the general formula (VIII);

AlR'_n'X'_3-n' (VIII)

in formula (VIII), R' is selected from H, C₁-C₂₀Alkyl or C₆-C₂₀Wherein X ' is halogen, n ' is not less than 1 and not more than 3, and n ' is an integer.

In some more preferred embodiments of the present invention, the alkyl aluminum compound is selected from at least one of trimethylaluminum, triethylaluminum, triisobutylaluminum, trioctylaluminum, diethylaluminum monohydrogen, diisobutylaluminum monohydrogen, diethylaluminum monochloride, diisobutylaluminum monochloride, ethylaluminum sesquichloride and ethylaluminum dichloride.

The catalyst of the present invention is not particularly limited in the kind and content of the external electron donor compound. The component 3 can be various external electron donor compounds which are commonly used in the field of olefin polymerization and can be used as cocatalysts of Ziegler-Natta catalysts.

In some preferred embodiments of the present invention, the molar ratio of component 3 to component 2 is 1 (0.1 to 500) in terms of silicon to aluminum. In some more preferred embodiments of the present invention, the molar ratio of component 3 to component 2 is 1 (1-300) in terms of silicon to aluminum. In some further preferred embodiments of the present invention, the molar ratio of component 3 to component 2 is 1 (3-100) in terms of silicon to aluminum.

In some preferred embodiments of the present invention, said component 3 external electron donor compound comprises at least one compound represented by the general formula (IX):

R^1" _m"R^2" _n"Si(OR^3")_4-m"-n" (IX)

in the general formula (IX), R^1"And R^2"Identical or different, each independently selected from H, halogen, C₁-C₂₀Alkyl or haloalkyl of, C₃-C₂₀Cycloalkyl or C₆-C₂₀Aryl of (a); r^3"Is selected from C₁-C₂₀Alkyl or haloalkyl of, C₃-C₂₀Cycloalkyl or C₆-C₂₀Aryl of (a); m 'and n' are integers from 0 to 3, and m '+ n' < 4.

In some more preferred embodiments of the present invention, said component 3 external electron donor compound is selected from the group consisting of trimethylmethoxysilane, trimethylethoxysilane, trimethylphenoxytriethylmethoxysilane, triethylethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, ethylisopropyldimethoxysilane, propylisopropyldimethoxysilane, diisopropyldimethoxysilane, diisobutyldimethoxysilane, isopropylisobutyldimethoxysilane, di-tert-butyldimethoxysilane, tert-butylmethyldimethoxysilane, tert-butylethyldimethoxysilane, tert-butylpropyldimethoxysilane, tert-butylisopropyldimethoxysilane, tert-butylbutylbutylbutyldimethoxysilane, tert-butylisobutyldimethoxysilane, tert-butyl (sec-butyl) dimethoxysilane, tert-butylpentyldimethoxysilane, tert-butyldimethoxysilane, tri-ethyldimethoxysilane, T-butylnonyldimethoxysilane, t-butylhexyldimethoxysilane, t-butylheptyldimethoxysilane, t-butyloctyldimethoxysilane, t-butyldecyldimethoxysilane, methyl-t-butyldimethoxysilane, cyclohexylmethyldimethoxysilane, cyclohexylethyldimethoxysilane, cyclohexylpropyldimethoxysilane, cyclohexylisobutyldimethoxysilane, dicyclohexyldimethoxysilane, cyclohexylt-butyldimethoxysilane, cyclopentylmethyl-dimethoxysilane, cyclopentylethyldimethoxysilane, cyclopentylpropyldimethoxysilane, cyclopentt-butyldimethoxysilane, dicyclopentyldimethoxysilane, cyclopentylcyclohexyldimethoxysilane, bis (2-methylcyclopentyl) dimethoxysilane, diphenyldimethoxysilane, diphenyldiethoxysilane, phenyltriethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, propyltrimethoxysilane, isopropyltrimethoxysilane, butyltrimethoxysilane, butyltriethoxysilane, isobutyltrimethoxysilane, t-butyltrimethoxysilane, sec-butyltrimethoxysilane, pentyltrimethoxysilane, isopentyltrimethoxysilane, cyclopentyltrimethoxysilane, cyclohexyltrimethoxysilane, diphenyldimethoxysilane, diphenyldiethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, n-propyltrimethoxysilane, vinyltrimethoxysilane, tetramethoxysilane, tetraethoxysilane, tetrabutoxysilane, 2-ethylpiperidinyl-2-t-butyldimethoxysilane, (1,1, 1-trifluoro-2-propyl) -2-ethylpiperidinyldimethoxysilane and at least one of (1,1, 1-trifluoro-2-propyl) -methyldimethoxysilane.

In some further preferred embodiments of the present invention, the component 3 external electron donor compound is selected from at least one of dicyclopentyldimethoxysilane, diisopropyldimethoxysilane, diisobutyldimethoxysilane, cyclohexylmethyldimethoxysilane, methyl-t-butyldimethoxysilane, and tetramethoxysilane.

In a third aspect, the present invention provides a prepolymerized catalyst for olefin polymerization, which comprises the catalyst component according to the first aspect of the present invention or a prepolymer obtained by prepolymerizing the catalyst according to the second aspect of the present invention with an olefin; wherein the pre-polymerization multiple of the prepolymer is 5-1000g of olefin polymer/g of catalyst component, preferably 10-500g of olefin polymer/g of catalyst component; preferably, the olefin used for the prepolymerization is ethylene or propylene.

In some embodiments of the invention, the temperature of the prepolymerization is from-20 to 80 ℃, preferably from 10 to 50 ℃.

In a fourth aspect, the present invention provides a process for the polymerisation of olefins carried out with the aid of a catalyst component according to the first aspect of the present invention, a catalyst according to the second aspect of the present invention or a prepolymerised catalyst according to the third aspect of the present invention. The olefin has the general formula CH₂Wherein R is hydrogen or C₁-C₆Alkyl or phenyl groups.

The olefin polymerization method provided by the invention can be used for olefin homopolymerization and can also be used for copolymerizing a plurality of olefins. The olefin is selected from at least one of ethylene, propylene, 1-n-butene, 1-n-pentene, 1-n-hexene, 1-n-octene and 4-methyl-1-pentene. Preferably, the olefin may be at least one of ethylene, propylene, 1-n-butene, 4-methyl-1-pentene, and 1-n-hexene. Preferably, the olefin is propylene.

In the preparation of polyolefin, the components of the catalyst provided by the invention, namely the catalyst component provided by the invention, the organic aluminum compound used as a cocatalyst and the external electron donor compound can be contacted before being contacted with an olefin monomer, and are referred to as pre-contact or pre-complexing in the industry; it is also possible to add the three components separately to the olefin monomer and then carry out the polymerization, i.e.without "precontacting". According to the olefin polymerization method provided by the invention, the components in the olefin polymerization catalyst are preferably subjected to a pre-contact method. The time of "precontacting" is 0.1 to 30min, preferably 1 to 10 min; the temperature of the "precontacting" is from-20 ℃ to 80 ℃, preferably from 10 to 50 ℃.

The catalyst is firstly prepolymerized to a certain extent in the presence of a small amount of olefin monomer to obtain a prepolymerized catalyst, and then the prepolymerized catalyst is further contacted with the olefin monomer to react to obtain the olefin polymer. This technique, known in the industry as a "prepolymerization" process, contributes to, among other things, increasing the polymerization activity of the catalyst and increasing the bulk density of the polymer. According to the olefin polymerization method provided by the invention, a prepolymerization process can be adopted, a prepolymerization process can also be not adopted, and a prepolymerization process is preferably adopted.

According to the olefin polymerization process of the present invention, the polymerization conditions may be conventional in the art, and the amount of the catalyst may be the amount of various catalysts in the prior art.

The invention adopts the diol ester with the content of the isomer (R, R-configuration and/or S, S-configuration isomer) with a specific optical configuration more than 95 percent as the precipitation aid a, has good precipitation effect, and the obtained catalyst has good particle shape and extremely low content of the precipitation aid; when the catalyst is used for preparing the impact copolymer, the catalyst has high activity, strong orientation capability and good hydrogen regulation sensitivity, and the copolymerization capability of the catalyst is greatly improved.

Detailed Description

In order that the present invention may be more readily understood, the following detailed description of the invention is given by way of example only, and is not intended to limit the scope of the invention.

As previously mentioned, the prior art has a higher residual amount of glycol ester compound in the catalyst as a precipitation aid, while the higher the residual amount of glycol ester compound, the lower the copolymerizability of the catalyst for the preparation of impact copolymers. In view of the above problems, the inventors of the present invention have studied and found that, when a glycol ester compound having a configuration represented by the general formula (I-a) and/or (I-b) is used as a precipitation assistant in the production of an olefin polymerization catalyst, the content of the glycol ester compound in the catalyst is less than 0.5% by weight, and when a glycol ester compound having a configuration represented by the general formula (I-c) and/or (I-d) is used as a precipitation assistant, the content of the glycol ester compound in the catalyst is more than 3% by weight. Therefore, the invention adopts the diol ester compound with the configuration shown as the general formula (I-a) and/or (I-b) and the isomer content of more than 95 percent as the precipitation aid, so that the obtained catalyst has better particle shape and extremely low content of the precipitation aid; when the catalyst is used for preparing the impact copolymer, the catalyst has high activity, strong orientation capability and good hydrogen regulation sensitivity, and the copolymerization capability of the catalyst is greatly improved. The present invention has been made based on the above findings.

The test method used in the present invention is as follows:

(1) the purity of the separation aid a glycol ester compound and the proportion of diastereoisomers are measured by adopting an Acquisty UPLC ultra-high performance liquid chromatograph of Waters company in the United states;

(2) the configuration of the separation assisting agent compound is determined by a Brukerdmx nuclear magnetic resonance instrument (300MHz, a solvent CDCl3, an internal standard TMS, a measuring temperature of 300K);

(3) content of diol ester compound in catalyst component: the determination is carried out by adopting an Acquity UPLC ultra-performance liquid chromatograph of Waters corporation in America;

(4) polymer Melt Index (MI): measured according to GB/T3682-2000;

(5) propylene polymer Isotacticity Index (II): determination by heptane extraction: 2g of dried polymer sample is put in an extractor and extracted by boiling heptane for 6 hours, and the ratio of the weight (g) of the polymer to 2(g) of the residue is dried to constant weight, namely the isotacticity;

(6) activity (Ac) calculation: catalyst activity (mass of polyolefin produced)/(mass of solid catalyst component) kg/g;

(7) bulk Density (BD) measurement: the polymer powder obtained in the preparation was allowed to freely fall from a height of 10cm in a funnel into a 100mL container, and the weight of the polymer powder in the container was weighed to M g, whereby the bulk density of the polymer was M/100g/cm³；

(8) The content of ethylene in the impact-resistant co-polypropylene is determined by Fourier infrared spectroscopy.

In the invention, an ultra-high performance liquid chromatograph is adopted, and the separation conditions of the liquid chromatogram are adjusted to ensure that the glycol ester with R, R-configuration and S, S-configuration have different retention times with the glycol ester with R, S-configuration, thereby distinguishing the glycol ester with R, R-configuration and S, S-configuration from the glycol ester with R, S-configuration. The specific separation conditions were:

(1) a chromatographic column: ACQUITY UPLC BEH Shield RP18(100 mm. times.2.1 mm, 1.7 μm);

(2) column temperature: 35 ℃;

(3) mobile phase: 75% methanol, 25% ultrapure water;

(4) the flow rate is 0.3 mL/min;

(5) the PDA detects a wavelength of 229 nm.

Under the condition, the retention time of the glycol ester in R, R-configuration and S, S-configuration is the same and relatively short, and the retention time of the glycol ester in R, S-configuration is relatively long. Meanwhile, the configuration of the diastereoisomer can be judged according to the nuclear magnetic resonance hydrogen spectrum signal peak of the diastereoisomer.

Examples

The synthesis method of the precipitation assistant a diol ester compound represented by the general formula (I) used in the examples of the present invention is as follows.

Compound 1: 2, 4-pentanediol dibenzoate (R, R-configuration + S, S-configuration): R, S-configuration ═ 99.1:0.16

(1) Preparation of a mixture of R, R-2, 4-pentanediol and S, S-2, 4-pentanediol

500g of 2, 4-pentanediol is added into 1200mL of anhydrous ether, the mixture is stirred evenly, the temperature is reduced to minus 50 ℃, the mixture is kept for 1 to 1.5 hours, the separated solid is collected by rapid filtration, the obtained solid is recrystallized at minus 20 ℃ by using ether continuously, and the recrystallization is repeated for three times, so that 184.4g of the final product with the purity of 99.4 percent (GC) is obtained.

¹H NMR(CDCl₃/TMS,300MHz)(ppm):1.202-1.258(m,6H,-CH(OH)CH₃),1.536-1.632(m,2H,-CH₂CH(OH)CH₃),4.048-4.211(m,2H,rac-CH(OH)CH₃)。

(2) Synthesis of 2, 4-pentanediol dibenzoate

259.3g of benzoyl chloride is added into 500mL of toluene to obtain a benzoyl chloride solution; 80g R mixture of R-2, 4-pentanediol and S, S-2, 4-pentanediol, 152.3g of anhydrous pyridine and 4.0g of 4-dimethylaminopyridine were added to 100mL of toluene, and after the solid was completely dissolved, the mixture was dropped into a benzoyl chloride solution, and the temperature was maintained at 50 ℃ or lower. After the dropwise addition, the temperature is raised to 80 ℃ for 4 hours of reaction, and the temperature is continuously raised to reflux reaction for 8 hours. After the reaction, the reaction mixture was cooled, filtered, part of toluene was removed by spinning, the filtrate was washed with an equivalent 10% sodium carbonate solution by vigorous stirring until the pH was 12, the filtrate was separated, the organic phase was washed with a saturated ammonium chloride solution until the pH was 6 to 7 or less, the organic phase was dried with anhydrous magnesium sulfate after separation, filtered, the solvent was dried by spinning, distilled under reduced pressure, and recrystallized with n-hexane at-20 ℃ to obtain 142.7g of a final product with a purity of 99.26% (LC). Wherein, the content of R, R-configuration and S, S-configuration isomers is 99.1%, the ratio of diastereoisomers (R, R-configuration + S, S-configuration) is 99.1: 0.16.

¹H NMR(CDCl₃/TMS,300MHz)(ppm):1.397-1.418(d,6H,-CH(OCO)CH₃),2.074-2.116(m,2H,-CH₂CH(OCO)CH₃),5.287-5.350(m,2H,-CH₂CH(OCO)CH₃),7.253-7.987(m,5H,-C₆H₅)。

Compound 2: 3, 5-heptanediol dibenzoate (R, R-configuration + S, S-configuration). R, S-configuration ═ 96.3:1.0

(1) Preparation of a mixture of R, R-3, 5-heptanediol and S, S-3, 5-heptanediol

Using a method similar to the procedure (1) in the synthesis of Compound 1, by substituting 2, 4-pentanediol with 3, 5-heptanediol, 181.3g of a mixture of R, R-3, 5-heptanediol and S, S-3, 5-heptanediol was prepared with a purity of 99.6% (GC).

¹H NMR(CDCl₃/TMS,300MHz)(ppm):0.923-0.972(m,6H,-CH(OH)CH₂CH₃),1.476-1.589(m,4H,-CH₂CH(OH)CH₂CH₃),1.607-1.627(m,2H,-CH₂CH(OH)CH₂CH₃),3.815-3.909(m,2H,rac-CH(OH)CH₃)。

(2) Synthesis of 3, 5-heptanediol dibenzoate

Using a method similar to the procedure (2) in the synthesis of Compound 1, a mixture of R, R-2, 4-pentanediol and S, S-2, 4-pentanediol was replaced with a mixture of R, R-3, 5-heptanediol and S, S-3, 5-heptanediol, and 142.7g of 3, 5-heptanediol dibenzoate was synthesized with a purity of 97.3% (LC). Wherein, the content of R, R-configuration and S, S-configuration isomers is 96.3 percent, the ratio of diastereoisomers (R, R-configuration + S, S-configuration) is 96.3: 1.0.

¹H NMR(CDCl₃/TMS,300MHz)(ppm):0.933-0.983(d,6H,-CH(OCO)CH₂CH₃),1.737-1.785(m,4H,-CH₂CH(OCO)CH₂CH₃),2.062-2.103(m,2H,-CH₂CH(OCO)CH₂CH₃),5.194-5.275(m,2H,-CH₂CH(OCO)CH₂CH₃),7.243-7.981(m,5H,-C₆H₅)。

The diol ester compound as the precipitation assistant used in the comparative example of the present invention includes the following compounds:

compound 3: 2, 4-pentanediol dibenzoate (R, R-configuration + S, S-configuration): R, S-configuration ═ 37:60

Wherein, the content of R, R-configuration isomer and S, S-configuration isomer is 37 percent, the ratio of diastereoisomers (R, R-configuration + S, S-configuration) R, S-configuration is 37: 60.

Compound 4: 3, 5-heptanediol dibenzoate (R, R-configuration + S, S-configuration). R, S-configuration ═ 35:61

Wherein, the content of R, R-configuration and S, S-configuration isomer is 35%, the diastereoisomer ratio (R, R-configuration + S, S-configuration) is 35: 61.

Example 1

Preparation of catalyst component

(1) Preparing a magnesium chloride alcoholate solution: 1400mL of isooctanol, 1400mL of toluene and 350g of anhydrous magnesium chloride are sequentially added into a reaction kettle repeatedly replaced by high-purity nitrogen, and the mixture is reacted for 3.5 hours under the conditions of 1300rpm of stirring speed and 115 ℃ of temperature to completely dissolve the mixture to form a uniform magnesium chloride alcoholic compound solution. Tetrabutyl titanate 52.5mL was added, the reaction was carried out at a stirring speed of 1300rpm and a temperature of 110 ℃ for 1.5 hours, and 1960mL of toluene was added thereto and the temperature was kept constant for half an hour. Then 140mL of toluene and 45g of compound 1 were added, and the mixture was reacted at a stirring speed of 1300rpm and a temperature of 50 ℃ for 0.5 hour, and then cooled to room temperature to form a magnesium chloride alcoholate solution containing a precipitation assistant.

(2) Preparation of catalyst component: the magnesium chloride alcoholate solution containing the precipitation assistant was dropwise added to a reactor containing 4200mL of titanium tetrachloride and 2800mL of toluene, which had been fully replaced with nitrogen, over a period of 3 hours, after the dropwise addition, the mixture was stirred to be sufficiently contacted at-25 ℃ for 0.5 hour, then the temperature was raised to 110 ℃ over 6 hours, 35g of di-n-butyl phthalate and 100mL of toluene were added, the temperature was maintained at 110 ℃ for 2 hours, the liquid was filtered, 6300mL of toluene and 700mL of titanium tetrachloride were added to the obtained solid intermediate, the mixture was stirred at 80 ℃ for 1 hour, cooled and filter-pressed, 6300mL of toluene and 700mL of titanium tetrachloride were added to the solid intermediate, the temperature was raised to 80 ℃ and 112g of di-n-butyl phthalate and 100mL of toluene were added to the solid intermediate, the temperature was maintained for 1 hour, the liquid was filtered, 5600mL of toluene and 1400mL of titanium tetrachloride were added to the obtained solid intermediate, the temperature was raised to 110 ℃ and the mixture was stirred for 1 hour, and the solid. Filtration, transfer and drying gave the olefin polymerization catalyst component 1.

Polymerization of Di, propylene

The catalyst component 1 obtained above was subjected to propylene polymerization. The specific method comprises the following steps: in a 5L autoclave, after sufficient replacement with vapor phase propylene, 5mL of a hexane solution of triethylaluminum (concentration of triethylaluminum: 0.5mmol/mL), lmL of a hexane solution of Cyclohexylmethyldimethoxysilane (CHMMS) (concentration of CHMMS: 0.10mmol/mL), 10mL of anhydrous hexane, and 10mg of solid catalyst component 1 were added at room temperature. The polymerization was carried out under two conditions, the polymerization results are shown in Table 1:

(1)4.5 normal liters of hydrogen and 2L of liquid propylene; the polymerization was carried out at 70 ℃ for 1 hour, the stirring was stopped, the unpolymerized propylene monomer was removed, and the polymer was collected.

(2)1.0 standard liters of hydrogen and 2L of liquid propylene; polymerization was carried out at 70 ℃ for 2 hours, the stirring was stopped, the unpolymerized propylene monomer was removed, and the polymer was collected.

Preparation of impact-resistant copolymerized polypropylene

The polymerization reaction is carried out on a set of horizontal gas-phase polypropylene pilot-plant test device, the polymerization reactor is two horizontal stirring reaction kettles which are connected in series, and the polymerization method comprises the following steps:

the catalyst component 1, triethyl aluminum and isobutyl dimethoxy silane are continuously added into a horizontal stirring reaction kettle from the front end of a first stirring kettle under the carrying of propylene, homopolymerized polypropylene is generated by polymerization under the condition of gas phase, and the reaction heat is taken away by the vaporization of the sprayed propylene. The polymer formed was discharged from the end of the stirred tank. The catalyst and the polymer move in the reactor in a mode of approximate plug flow, the polymerization temperature is 66 ℃ or a specified temperature, and the reaction pressure is 2.3 MPa.

The homopolypropylene was discharged from the first reactor and transferred to the second horizontal stirred tank reactor through a transfer device provided between the two reactors. The polymer enters from the front end of the second stirring kettle, the impact copolymer polypropylene is generated by polymerization under the condition of introducing ethylene, and the reaction heat is taken away by the vaporization of the sprayed propylene. The molar ratio of ethylene to propylene is maintained at 0.38-0.40 during the polymerization. The polymer formed was discharged from the end of the stirred tank. The catalyst and the polymer move in the reactor in a mode of approximate plug flow, the polymerization temperature is 66 ℃ or a specified temperature, and the reaction pressure is 2.2 MPa. The polymer obtained by the reaction is degassed and subjected to wet nitrogen deactivation treatment to obtain the impact-resistant polypropylene copolymer, and the polymerization result is shown in Table 2.

Example 2

Catalyst component preparation the same as in example 1 except that compound 1 was replaced with compound 2 in step (1) to prepare catalyst component 2.

Propylene was polymerized in the same manner as in example 1 except that catalyst component 1 was replaced with catalyst component 2 and the polymerization results were as shown in Table 1.

An impact-resistant copolypropylene was prepared as in example 1, except that catalyst component 1 was replaced by catalyst component 2 and the polymerization results are shown in Table 2.

Example 3

Catalyst component preparation the catalyst component 3 was prepared as in example 1, except that compound 1 was replaced with compound 2 in step (1) and di-n-butyl phthalate (DNBP) was replaced with diisobutyl phthalate (DIBP) in step (2).

Propylene was polymerized in the same manner as in example 1 except that catalyst component 1 was replaced with catalyst component 3 and the polymerization results were as shown in Table 1.

An impact-resistant copolypropylene was prepared as in example 1, except that catalyst component 1 was replaced by catalyst component 3 and the polymerization results are shown in Table 2.

Example 4

Preparation of catalyst component

(1) Preparing a magnesium chloride solution: 350g of anhydrous magnesium chloride, 4667mL of toluene, 576mL of epichlorohydrin and 649mL of tributyl phosphate are sequentially added into a reaction kettle repeatedly replaced by high-purity nitrogen at normal temperature, the stirring speed is 1300rpm, the temperature is raised to 55 ℃, and the mixture is reacted for 3.0 hours to be completely dissolved to form a uniform magnesium chloride solution.

(2) Preparation of catalyst component: the temperature was lowered to-28 ℃ and 4100mL of titanium tetrachloride, 290mL of toluene, 58g of Compound 1, and 36g of di-n-butyl phthalate were added dropwise to the above magnesium chloride solution. After the dropwise addition, the mixture was stirred to be in full contact with the reaction mixture at-28 ℃ for 1.0 hour, then the temperature was raised to 80 ℃ over 4.5 hours, the temperature was kept constant for 1.5 hours, then the liquid was removed by pressure filtration, 8750mL of toluene was added, and the mixture was washed twice. 51g of di-n-butyl phthalate and 6560mL of toluene were added, the temperature was maintained at 80 ℃ for 1 hour, 4375mL of titanium tetrachloride was added, the mixture was heated to 110 ℃ and stirred for 1 hour, 4200mL of toluene and 2800mL of titanium tetrachloride were added, stirring was carried out for 1 hour, liquid was removed by pressure filtration, 4200mL of toluene and 2800mL of titanium tetrachloride were added, stirring was carried out for 1 hour, and the solid obtained after liquid removal by pressure filtration was washed 5 times with 6000mL of hexane. Press-filtering, transferring and drying to obtain the olefin polymerization catalyst component 4.

Polymerization of Di, propylene

The catalyst component 4 obtained above was subjected to propylene polymerization. The specific method comprises the following steps: in a 5L autoclave, after sufficient replacement with vapor phase propylene, 5mL of a hexane solution of triethylaluminum (concentration of triethylaluminum: 0.5mmol/mL), lmL of a hexane solution of Cyclohexylmethyldimethoxysilane (CHMMS) (concentration of CHMMS: 0.10mmol/mL), 10mL of anhydrous hexane, and 10mg of solid catalyst component 4 were added at room temperature. The polymerization was carried out under two conditions, the polymerization results are shown in Table 1:

Preparation of impact-resistant copolymerized polypropylene

catalyst component 4, triethyl aluminum and isobutyl dimethoxy silane are continuously added into a horizontal stirring reaction kettle from the front end of a first stirring kettle under the carrying of propylene, homopolymerized polypropylene is generated by polymerization under the condition of gas phase, and the reaction heat is taken away by the vaporization of the sprayed propylene. The polymer formed was discharged from the end of the stirred tank. The catalyst and the polymer move in the reactor in a mode of approximate plug flow, the polymerization temperature is 66 ℃ or a specified temperature, and the reaction pressure is 2.3 MPa.

Example 5

Catalyst component preparation the same as in example 4 except that compound 1 was replaced with compound 2 in step (1) to prepare catalyst component 5.

Propylene was polymerized in the same manner as in example 4 except that catalyst component 4 was replaced with catalyst component 5, and the polymerization results were as shown in Table 1.

An impact co-polypropylene was prepared as in example 4 except that catalyst component 4 was replaced with catalyst component 5 and the polymerization results are shown in Table 2.

Example 6

Catalyst component 6 was prepared as in example 4 except that compound 1 was replaced with compound 2 in step (1) and di-n-butyl phthalate (DNBP) was replaced with diisobutyl phthalate (DIBP) in step (2).

Propylene was polymerized in the same manner as in example 4 except that catalyst component 4 was replaced with catalyst component 6 and the polymerization results were as shown in Table 1.

An impact co-polypropylene was prepared as in example 4 except that catalyst component 4 was replaced with catalyst component 6 and the polymerization results are shown in Table 2.

Comparative example 1

Catalyst component preparation the same as in example 1 except that compound 1 was replaced with compound 3 in step (1) to prepare catalyst component 7.

Propylene was polymerized in the same manner as in example 1 except that catalyst component 1 was replaced with catalyst component 7 and the polymerization results were as shown in Table 1.

An impact co-polypropylene was prepared as in example 1 except that catalyst component 1 was replaced with catalyst component 7 and the polymerization results are shown in Table 2.

Comparative example 2

Catalyst component preparation the same as in example 2 except that compound 2 was replaced with compound 4 in step (1) to prepare catalyst component 8.

Propylene was polymerized in the same manner as in example 2 except that the catalyst component 2 was replaced with the catalyst component 8, and the polymerization results were as shown in Table 1.

An impact-resistant copolypropylene was prepared as in example 2, except that catalyst component 2 was replaced with catalyst component 8 and the polymerization results are shown in Table 2.

Comparative example 3

Catalyst component preparation the same as in example 4 except that compound 1 was replaced with compound 3 in step (1) to prepare catalyst component 9.

Propylene was polymerized in the same manner as in example 4 except that catalyst component 4 was replaced with catalyst component 9, and the polymerization results were as shown in Table 1.

An impact co-polypropylene was prepared as in example 4 except that catalyst component 4 was replaced with catalyst component 9 and the polymerization results are shown in Table 2.

Comparative example 4

Catalyst component preparation the same as in example 5 except that compound 2 was replaced with compound 4 in step (1) to prepare catalyst component 10.

Propylene was polymerized in the same manner as in example 5 except that the catalyst component 5 was replaced with the catalyst component 10, and the polymerization results were as shown in Table 1.

An impact co-polypropylene was prepared as in example 5 except that catalyst component 5 was replaced with catalyst component 10 and the polymerization results are shown in Table 2.

TABLE 1

TABLE 2^a

C2 is the total ethylene content in the co-polypropylene, RCC2 is the ethylene content in the rubber phase, and RC is the rubber phase content in the co-polypropylene.

As can be seen from the data in Table 1, when the diol ester compound with a specific optical configuration is used as a precipitation aid, the content of the diol ester in the precipitation aid in the obtained catalyst is extremely low, the polymerization activity of the catalyst can be improved, and the prepared polymer keeps high bulk density and isotacticity.

As can be seen from the data in Table 2, when the catalyst of the present invention is used to prepare impact co-polypropylene, the ethylene content in the co-polypropylene and the ethylene content in the rubber phase are higher under the same ethylene/propylene molar ratio, indicating that the catalyst of the present invention has better copolymerization capability and is more suitable for preparing impact co-polypropylene.

It should be noted that the above-mentioned embodiments are only for explaining the present invention, and do not constitute any limitation to the present invention. The present invention has been described with reference to exemplary embodiments, but the words which have been used herein are words of description and illustration, rather than words of limitation. The invention can be modified, as prescribed, within the scope of the claims and without departing from the scope and spirit of the invention. Although the invention has been described herein with reference to particular means, materials and embodiments, the invention is not intended to be limited to the particulars disclosed herein, but rather extends to all other methods and applications having the same functionality.

Claims

1. A catalyst component for olefin polymerization, which comprises magnesium, titanium, halogen, an internal electron donor compound and a precipitation assistant, wherein the precipitation assistant comprises at least one precipitation assistant a shown as a general formula (I);

wherein R is₁And R₂Same or different, each independently selected from substituted or unsubstituted C₁-C₁₀Alkyl of (C)₃-C₁₀Cycloalkyl of, C₆-C₁₀Aryl or C of₇-C₁₀Aralkyl group of (1); r₃And R₄Same or different, each independently selected from substituted or unsubstituted C₁-C₂₀Alkyl of (C)₃-C₂₀Cycloalkyl of, C₆-C₂₀Aryl or C of₇-C₂₀Aralkyl group of (1);

the auxiliary precipitating agent a shown in the general formula (I) comprises optical isomers shown in the general formula (I-a) and/or the general formula (I-b), and the content of the optical isomers shown in the general formula (I-a) and/or the general formula (I-b) is more than 90 wt%;

2. the catalyst component according to claim 1 in which the content of optical isomers represented by the general formula (I-a) and/or general formula (I-b) is greater than 95% by weight.

3. The catalyst component according to claim 1 in which the content of optical isomers represented by the general formula (I-a) and/or general formula (I-b) is greater than 98% by weight.

4. The catalyst component according to claim 1 in which in the formula (I) R is₁And R₂Each independently selected from substituted or unsubstituted C₁-C₈Alkyl of (C)₃-C₈Cycloalkyl or C₆-C₈Aryl of (a); r₃And R₄Each independently selected from substituted or unsubstituted C₁-C₁₀Alkyl of (C)₃-C₁₀Cycloalkyl or C₆-C₁₀Aryl group of (1).

5. The catalyst component according to claim 1 in which in the formula (I) R is₁And R₂Each independently selected from substituted or unsubstituted C₁-C₄Alkyl groups of (a); r₃And R₄Each independently selected from substituted or unsubstituted C₅-C₁₀Alkyl, cycloalkyl, aryl or aralkyl.

6. The catalyst component according to claim 1, wherein the content of the precipitation aid a is less than 1.0 wt. -%, based on the total weight of the catalyst component.

7. The catalyst component according to claim 6 in which the content of the precipitant aid a is less than 0.5 wt.%.

8. The catalyst component according to claim 6 in which the content of the precipitant aid a is less than 0.2 wt%.

9. The catalyst component according to claim 6 in which the content of the precipitant aid a is less than 0.1 wt%.

10. The catalyst component according to any of claims 1 to 9 wherein the precipitation aid optionally comprises a precipitation aid b of formula (II);

Ti(OR₇)_nX_4-n (II)

11. The catalyst component according to any of claims 1 to 9, wherein the internal electron donor compound comprises at least one phthalate compound of formula (III);

wherein R is₅And R₆Same or different, each independently selected from substituted or unsubstituted C₁-C₁₀Alkyl of (C)₃-C₁₀Cycloalkyl of, C₆-C₁₀Aryl or C of₇-C₁₀An alkylaryl group of (a).

12. The catalyst component according to claim 11 in which R is₅And R₆Each independently selected from substituted or unsubstituted C₁-C₈Alkyl of (C)₃-C₈Cycloalkyl or C₆-C₈Aryl group of (1).

13. The catalyst component according to claim 11 in which R is₅And R₆Each independently selected from substituted or unsubstituted C₁-C₆Alkyl group of (1).

14. The catalyst component according to any of claims 1 to 9, characterized in that the titanium content is from 1.0 wt% to 8.0 wt%, based on the total weight of the catalyst component; the content of the magnesium is 10.0-70.0 wt%; the content of the halogen is 20.0-85.0 wt%; the content of the internal electron donor compound is 2.0 wt% -30.0 wt%.

15. The catalyst component according to any of claims 1 to 9 in which the titanium content is between 1.6% and 6.0% by weight.

16. The catalyst component according to claim 15 in which the magnesium content is from 10.0% to 40.0% by weight.

17. The catalyst component according to claim 16 in which the halogen content is between 30.0% and 85.0% by weight.

18. The catalyst component of claim 17, wherein the internal electron donor compound is present in an amount of 3.0 wt% to 30.0 wt%.

19. The catalyst component according to claim 11, comprising the reaction product of a magnesium compound, a titanium compound, at least one internal electron donor compound of formula (III) and at least one precipitation aid a of formula (I);

wherein the dosage of the precipitation aid a is 0.005-0.3 mol per mol of the magnesium compound.

20. The catalyst component according to claim 19 in which the precipitant aid a is used in an amount of 0.01 to 0.05 mol.

21. A catalyst for the polymerization of olefins comprising the following components:

component 1, the catalyst component of any one of claims 1 to 20;

component 2, an alkyl aluminum compound;

and optionally component 3, an external electron donor compound;

wherein the molar ratio of the component 1 to the component 2 is (5-5000):1 in terms of titanium to aluminum.

22. The catalyst of claim 21 wherein the molar ratio of component 1 to component 2 is (20-1000):1, in terms of titanium to aluminum.

23. The catalyst of claim 21 wherein the molar ratio of component 1 to component 2 is (50-500):1, in terms of titanium to aluminum.

24. A prepolymerized catalyst for the polymerization of olefins comprising the catalyst component according to any of claims 1 to 20 or a prepolymer obtained by prepolymerizing the catalyst according to any of claims 21 to 23 with olefins; wherein the pre-polymerization multiple of the prepolymer is 5-1000g of olefin polymer/g of catalyst component.

25. The prepolymerized catalyst according to claim 24 wherein the prepolymer has a prepolymerization multiple of 10 to 500g olefin polymer/g catalyst component.

26. The prepolymerized catalyst according to claim 24 wherein the olefin used for the prepolymerization is ethylene or propylene.

27. A process for the polymerization of olefins having the general formula CH by polymerization of an olefin in the presence of a catalyst component according to any of claims 1 to 20 or a catalyst according to any of claims 21 to 23 or a prepolymerised catalyst according to any of claims 24 to 26₂Wherein R is hydrogen or C₁-C₆Alkyl or aryl of (a).