JPH072793B2 - Method for producing polyolefin - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for producing a polyolefin using a novel catalyst system. More specifically, it relates to a method for producing a polyolefin using a highly active catalyst composed of a transition metal complex having a specific composition and an aluminoxane.

[Conventional technology]

Conventionally, as a method for producing a polyolefin, a method using a so-called Ziegler catalyst composed of a combination of a transition metal compound and an organoaluminum compound has been known, and many proposals have been made. In addition, recently
An extremely highly active polymerization method using aluminoxane as an organoaluminum compound component has also been proposed in JP-A-58-19309. Although the activity of this catalyst system is extremely high, in order to express such high activity,
It is known that it is necessary to remarkably increase the ratio of aluminoxane used as a catalyst component to the transition metal compound component. As a proposal for improving this point, there is, for example, JP-A-60-260602, but it is hard to say that the effect is sufficient.

[Problems to be solved by the invention]

An object of the present invention is to provide a catalyst system in which the above-mentioned problems of the prior art are improved and which is capable of producing a polyolefin with sufficiently high activity even when the use ratio of aluminoxane used as a catalyst component is lowered. .

[Means for solving problems]

As a result of earnest studies to achieve the above-mentioned object, the inventors have found that (A) (1) the general formula R ¹ _m (C ₅ R ² _n ) ₂ MR ³ R ⁴ (wherein (C ₅ R ² _n ) Is a cyclopentadienyl group or a substituted cyclopentadienyl group, R ² is a hydrogen atom or a hydrocarbyl group having 1 to 20 carbon atoms, and R ² is the same or different from each other. Also, two adjacent carbon atoms forming a cyclopentadienyl group or a substituted cyclopentadienyl group may form a ring having 4 to 6 carbon atoms together with R ² bonded to each other, and R ¹ is A group for connecting _two (C ₅ R _{2 n} ), which is an alkylene group having 1 to 4 carbon atoms, and R ³ and R ⁴ are each a hydrocarbyl group having 1 to 20 carbon atoms or a halogen atom. , M is titanium, zirconium, vanadium or hafnium, and m is 0 or 1 and n is 5 when m is 0, and is 4 when m is 1.), and (2) the general formula AlR ⁵ _p X _3-p (wherein R is ⁵ is an alkyl group having at most 12 carbon atoms, X is a halogen atom or a hydrogen atom, and p is 1 to
It is a number of three. ), A transition metal complex obtained by reacting with an organoaluminum compound represented by the formula (B), and (B) a general formula AIR ⁶ _q X _3-q (wherein R ⁶ is an alkyl group having at most 6 carbon atoms). And X is a halogen atom, and q is 2 or 3.) It was found that the above object can be achieved by using a catalyst system comprising an organoaluminum compound represented by the formula (2) and an aluminoxane obtained by the reaction of water. Has reached the present invention.

The transition metal compound used in the present invention has a general formula:
It is represented by R ¹ _m (C ₅ R ² _n ) ₂ MR ³ R ⁴ . R ² is a hydrogen atom or a hydrocarbyl group having 1 to 20 carbon atoms such as alkyl, alkenyl, aryl, alkylaryl and aralkyl, R ² may be the same or different from each other, Two adjacent carbon atoms forming a cyclopentadienyl group or a substituted cyclopentadienyl group are bonded to each other R ²
Together with this, a ring having 4 to 6 carbon atoms may be formed. R ¹ is a group that bonds ^two (C ₅ R ² _n ) and is an alkylene group having 1 to 4 carbon atoms. R ³ and R ⁴ each have 1 to 20 carbon atoms
Is a hydrocarbyl group such as an alkyl, aryl, alkenyl, alkylaryl or aralkyl group, or a halogen atom. M is titanium, zirconium, vanadium or hafnium. m is 0 or 1, n is 5 when m is 0, and 4 when m is 1.
Is.

Specific examples of the hydrocarbyl group in R ² , R ³ and R ⁴ include methyl, ethyl, propyl, butyl, amyl, isoamyl, hexyl, isobutyl, heptyl, octyl, nonyl, decyl, cetyl, 2-ethylhexyl, Examples thereof include phenyl. Specific examples of the alkylene group for R ¹ include methylene, ethylene, propylene and the like.

Specific examples of the compound represented by the general formula R ¹ _m (C ₅ R ² _n ) ₂ MR ³ R ⁴ include bis (cyclopentadienyl) dimethyltitanium, bis (methylcyclopentadienyl) dimethyltitanium, and bis ( Pentamethylcyclopentadienyl) dimethyltitanium, bis (cyclopentadienyl) methylchlorotitanium, bis (cyclopentadienyl) dichlorotitanium, bis (indenyl) dimethyltitanium, ethylenebis (tetrahydroindenyl) dimethyltitanium, ethylenebis (Tetrahydroindenyl) dichlorotitanium, bis (cyclopentadienyl) dimethylzirconium, bis (methylcyclopentadienyl) dimethylzirconium, bis (pentamethylcyclopentadienyl) dimethylzirconium,
Bis (cyclopentadienyl) methylchlorozirconium, bis (cyclopentadienyl) dichlorozirconium, bis (indenyl) dimethylzirconium, ethylenebis (tetrahydroindenyl) dimethylzirconium, ethylenebis (tetrahydroindenium) dichlorozirconium, bis ( Examples include cyclopentadienyl) dichlorovanadium, bis (cyclopentadienyl) dimethylhafnium, and bis (cyclopentadienyl) dichlorohafnium.

In the present invention, the organic aluminum compound used for obtaining the transition metal complex is represented by the general formula AlR _p ⁵ X _3-p. R ⁵ is an alkyl group having at most 12 carbon atoms, X is a halogen atom or a hydrogen atom, and p is 1 to
It is a number of three. Specific examples thereof include trialkylaluminums such as trimethylaluminum, triethylaluminum, tri-n-propylaluminum, tri-isopropylaluminum, tri-n-butylaluminum, trihexylaluminum, dimethylaluminum hydride, diethylaluminum hydride, and -N-Propyl aluminum hydride, di-
Dialkyl aluminum hydrides such as n-butyl aluminum hydride, di-isobutyl aluminum hydride and dihexyl aluminum hydride, dialkyl aluminum halides such as dimethyl aluminum chloride, diethyl aluminum chloride, di-n-propyl aluminum chloride and di-isobutyl aluminum chloride, Aluminum sesquichlorides such as methyl aluminum sesquichloride, ethyl aluminum sesquichloride, n-propyl aluminum sesquichloride, isobutyl aluminum sesquichloride, and methyl aluminum dichloride, ethyl aluminum dichloride, n-propyl aluminum dichloride, isobutyl aluminum dichloride, etc. Alkylaluminum dihalides such like. When the transition metal compound and the organoaluminum compound are reacted, the amount of the organoaluminum compound used is 0.1 to 200 (molar ratio) with respect to the transition metal compound.
Is preferably in the range of 0.2 to 50 (molar ratio). The reaction is preferably carried out in an inert hydrocarbon solvent, usually at 20 ℃ or higher, preferably at 40 ~ 150 ℃, 1
The reaction is carried out for 5 minutes to 6 hours, preferably 30 minutes to 3 hours. When the transition metal complex obtained as described above is insoluble in hydrocarbons, it may be sufficiently washed with hydrocarbons and then used as a slurry as it is, or may be dried under reduced pressure and then used in powder form. Is also good.
Further, when the transition metal complex is dissolved in hydrocarbon, it may be used as a solution as it is, but preferably −
It is preferable to precipitate the solid by cooling to 70 ° C. to 20 ° C., wash at that temperature with a hydrocarbon, and then use it as a slurry as it is, or after drying under reduced pressure, use it in the form of powder.

In the present invention, an aluminoxane obtained by reacting an organoaluminum compound with water is used as one of the catalyst components. The organoaluminum compound used here is represented by the general formula AlR ⁶ _q X _3-q . R ⁶ is an alkyl group having at most ⁶ carbon atoms, X is a halogen atom, and q is 2 or 3.

Specific examples thereof include trimethyl aluminum, triethyl aluminum, triisopropyl aluminum, triisobutyl aluminum, trihexyl aluminum, dimethyl aluminum chloride, diethyl aluminum chloride, and diisopropyl aluminum chloride. Particularly favorable results are achieved when using trimethylaluminum. The reaction between the organoaluminum compound and water is a condensation reaction, and the product obtained varies depending on the molar ratio of the reaction components and the reaction conditions. Or (In the formula, R ⁷ is an alkyl group having at most 6 carbon atoms or a halogen atom, R ⁸ is an alkyl group having at most 6 carbon atoms, and when R ⁷ is an alkyl group, R ⁷ is The same and r is an integer of 1 or more.) Or a mixture thereof. The above reaction can be easily carried out by gradually adding a predetermined amount of water to an organoaluminum compound dissolved in an inert hydrocarbon solvent such as toluene, and slightly heating it if necessary. It is also possible to use water of crystallization such as a substance or aluminum sulfate hydrate.

The amount of water used is usually 0.1 to 5.0 mol ratio, preferably 0.5 to 3.0 mol ratio, based on the organoaluminum compound. If it deviates from this range, the catalytic activity will drop sharply.

The method of the present invention is applicable to the polymerization of all olefins that can be polymerized with a Ziegler catalyst, and specific examples of suitable olefins include ethylene, propylene, 1-butene,
Examples thereof include 1-hexene, 4-methyl-1-pentene, 1-octene, 1-decene, vinylcyclohexane, and styrene, and it is also possible to copolymerize using a mixed component of two or more kinds thereof. Further, copolymerization with dienes for the purpose of modifying the polyolefin is also preferably carried out. Specific examples of dienes include butadiene, 1,4-hexadiene, ethylidene norbornene, and dicyclopentadiene. In the method of the present invention, the olefin polymerization method is not particularly limited, and liquid phase polymerization methods such as slurry polymerization and solution polymerization, gas phase polymerization, etc. are possible. The liquid phase polymerization method is usually carried out in a hydrocarbon solvent, but as the hydrocarbon solvent, butane, isobutane, hexane, octane, decane, cyclohexane, benzene,
Inert hydrocarbons such as toluene and xylene may be used alone or as a mixture. Further, the raw material olefin can be used as it is as a solvent. The polymerization temperature is generally -50 to 200 ° C, practically -20 to 150 ° C.
Is. The gas phase polymerization is carried out in a gas phase state substantially free of a solvent, and a known reactor such as a fluidized bed stirring tank can be used. The polymerization temperature is usually 0 to 150 ° C, preferably 20 to 100 ° C.

In the method of the present invention, a mixture prepared by mixing the catalyst component (A) and the catalyst component (B) may be supplied to the reaction system, or the above components may be supplied separately to the reaction system. The ratio of the component (A) and the component (B) used is such that the amount of aluminum in the component (B) is 1 to 10 ⁵ g atom per 1 g atom of titanium, zirconium, vanadium or hafnium in the component (A). , preferably in the range of 10 to 10 ⁴ g atoms. Further, in the present invention, the molecular weight of the polymer is controlled by the use of hydrogen and / or the polymerization temperature.

〔The invention's effect〕

According to the method of the present invention, the catalytic activity is very high, even if the use ratio of aluminoxane is greatly reduced as compared with the conventional catalyst system consisting of a transition metal compound and aluminoxane,
A polyolefin can be efficiently produced.

〔Example〕

Hereinafter, the present invention will be described in more detail with reference to examples.

Example 1 Preparation of Transition Metal Complex 200 mmol of bis (cyclopentadienyl) dichlorotitanium and 50 ml of n-heptane were added into a 300 ml three-necked flask whose atmosphere was replaced with nitrogen. After adding 100 mmol of an n-heptane solution of dimethylaluminum chloride (1 mol /), the temperature was raised to 80 ° C. and the reaction was carried out for 2 hours to obtain a green solution. The solution was cooled to -30 ° C, and the precipitated solid substance was washed twice with 200 ml of n-heptane and dried under reduced pressure to obtain a green solid.

Production of aluminoxane 100 mmol of copper sulfate pentahydrate (500 mmol of water) was put into a 300 ml three-necked flask whose atmosphere was replaced with nitrogen, and 100 ml of toluene was added.
Suspended in. Next, trimethylaluminum 300mmo
l is added at 30 ° C. and the reaction is continued at that temperature for 48 hours. Then, the reaction product was filtered through a glass filter to obtain a solution of methylaluminoxane. When toluene was distilled off, 8.2 g of white crystals were obtained.

Polymerization of ethylene 3 Isobutane 2 in stainless steel autoclave
Then, 0.04 mmol of the above transition metal complex in terms of Ti and 4 mmol of the above methylaluminoxane were charged, and the internal temperature was raised to 50 ° C. Then, ethylene was injected under pressure so that the ethylene partial pressure became 5 kg / cm ^2, and the polymerization was started. Ethylene partial pressure 5 kg / cm
Polymerization was carried out for 30 minutes while keeping it at ² . Then, the content gas was released to the outside of the system to terminate the polymerization. As a result, 525 g of a white powdery polymer was obtained. The catalytic activity was 26300 kg / mol · Ti · hr.

Examples 2 to 5 In Example 1, transition metal complexes were prepared in the same manner as in Example 1 except that the organoaluminum compounds shown in Table 1 were used instead of dimethylaluminum chloride, and the transition metal complex usage amounts are shown. Polymerization of ethylene was carried out in the same manner as in Example 1 except that it was changed as shown in 1. The results are shown in Table 1.

Comparative Example 1 Polymerization of ethylene was carried out in the same manner as in Example 1 except that 0.04 mmol of bis (cyclopentadienyl) dichlorotitanium was used in place of the transition metal complex in the polymerization of ethylene in Example 1. As a result, 112 g of a white powdery polymer
was gotten.

The catalytic activity was 5600 kg / mol · Ti · hr.

Example 6 Copolymerization of ethylene and propylene 600 ml of dehydrated hexane and 1.2 ml of the transition metal complex prepared in Example 1 were placed in a 1.2-nitrogen-substituted stainless steel autoclave.
0.01 mmol and 1 mmol of methylaluminoxane were charged, and the internal temperature was raised to 40 ° C. Then, 150 g of propylene was injected with ethylene to initiate polymerization. Ethylene partial pressure
Polymerization was carried out for 30 minutes while maintaining 3 kg / cm ² , and then methanol was added to terminate the polymerization. The polymer solution was added to a large amount of methanol to precipitate the polymer, which was dried under reduced pressure at 40 ° C. to give 14.8 g of ethylene-
A propylene copolymer was obtained. Catalytic activity is 2960kg / m
It was ol / Ti / hr. The ethylene content of this polymer is 72
% By weight.

Examples 7 to 10 In Example 1, transition metal complexes were prepared in the same manner as in Example 1 except that the transition metal compounds shown in Table 2 were used instead of bis (cyclopentadienyl) dichlorotitanium. Copolymerization of ethylene and propylene was performed in the same manner as in Example 6 except that the amount of the complex used was changed as shown in Table 2. The results are shown in Table 2.

Comparative Example 2 In the copolymerization of ethylene and propylene of Example 6,
Copolymerization of ethylene and propylene was carried out in the same manner as in Example 6 except that 0.01 mmol of bis (cyclopentadienyl) dichlorozirconium was used instead of the transition metal complex. As a result, 3.7 g of ethylene-propylene copolymer was obtained. The catalytic activity was 740 kg / mol · Zr · hr.

Example 11 Polymerization of Propylene A nitrogen autoclave 1.2 stainless steel autoclave was charged with 400 ml of dehydrated toluene, 400 ml of propylene, 0.02 mmol of the transition metal complex obtained in Example 7 and 2 mmol of the methylaluminoxane obtained in Example 1, and 20 ° C. In, polymerization of propylene was carried out for 10 hours. After adding a small amount of methanol to stop the polymerization, purge unreacted propylene,
Toluene was removed from the obtained toluene solution of the polymer and dried to obtain 88 g of atactic polypropylene having a molecular weight of 15,000. Catalytic activity is 440kg / mol ・ Zr
・ It was hr.

Example 12 A transition metal complex was prepared in the same manner as in Example 1 except that ethylenebis (tetrahydroindenyl) dichlorozirconium was used in place of bis (cyclopentadienyl) dichlorotitanium in Example 1. Polymerization of ethylene was carried out in the same manner as in Example 1 except that 0.035 mmol of this transition metal complex was used. As a result, 585 g of a white powdery polymer was obtained. The catalytic activity was 33400 kg / mol · Zr · hr.

[Brief description of drawings]

FIG. 1 is a flow chart showing the components and preparation steps of the catalyst system used in the method of the present invention.

Claims (1)

[Claims] (A) (1) General formula R ¹ _m (C ₅ R ² _n ) ₂ MR ³ R ⁴ (wherein (C ₅ R ² _n ) is a cyclopentadienyl group or a substituted cyclopentadiene group) An enyl group, R ² represents a hydrogen atom or a hydrocarbyl group having 1 to 20 carbon atoms, R ^{2 s} may be the same or different from each other, and may be a cyclopentadienyl group or a substituted cyclopenta group. Two adjacent carbon atoms forming a dienyl group may form a ring having 4 to 6 carbon atoms together with R ² which can be bonded to each other, and R ¹ bonds ^two (C ₅ R ² _n ) A alkylene group having 1 to 4 carbon atoms, R ³ and R ⁴ each represent a hydrocarbyl group having 1 to 20 carbon atoms or a halogen atom, and M represents titanium, zirconium, vanadium or hafnium. , M is 0 or 1, n is 5 when m is 0, and m is When is 4.) A transition metal compound represented by (2) in the general formula AlR ⁵ _{p X 3-p (wherein,} R ⁵ is 12 alkyl groups at most carbon atoms, X is a halogen Represents an atom or a hydrogen atom, and p is 1 to
It is a number of three. ), A transition metal complex obtained by reacting with an organoaluminum compound represented by the formula (B), and (B) a general formula AIR ⁶ _q X _3-q (wherein R ⁶ is an alkyl group having at most 6 carbon atoms). And X is a halogen atom, and q is 2 or 3.) of a polyolefin characterized by polymerizing an olefin using a catalyst system comprising an aluminoxane obtained by reacting an organoaluminum compound represented by Production method.