JPH11246583A - Hafnium compound having bis-substituted cyclopentadienyl ligand - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a new hafnium compound consisting of a specific hafnium compound having a bis-bustituted cyclopentadienyl ligand, capable of producing a high molecular weight stereoregular olefinic polymer in a good efficiency and useful as an olefin polymerization catalyst component, etc. SOLUTION: This hafnium compound having a bis-substituted cyclopentadienyl ligand, is a new hafnium compound expressed by the formula [M is hafnium; (R<1> n -C5 H5-n ) and (R<1> q -C5-q ) are each a substituted cyclopntadienyl group; R<1> is a hydrocarbon group; X is H, a halogen or a hydrocarbon group; (n), (q) are each 2 to 4 integer], [e.g.; bis (1,2,4-trimethyl-cyclopentadienyl) hafnium dichloride], and useful as a polymerization catalyst component of an olefin capable of producing a high molecular weight olefinic polymer in a good efficiency. The compound is obtained by reacting 1,2,4-trimethycyclopentadiene with n-butyllithium in THF, and then adding for reacting a methylene chloride suspension liquid of hafnium tetrachloride.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a novel hafnium compound having a bis-substituted cyclopentadienyl ligand. The compound of the present invention is useful as an olefin polymerization catalyst component for producing a high-molecular-weight polyolefin.

[0002]

2. Description of the Related Art Since it was found that a catalyst comprising bis (cyclopentadienyl) zirconium dichloride and methylaluminoxane polymerized olefins with high activity (JP-A-58-19309, Makromol. Chem.). .
Rapid Commun., 4, 417 (1983)) and various metallocene compounds have been studied as catalyst components for olefin polymerization.

Among the metallocene compounds, zirconium compounds having a substituent on the cyclopentadienyl ring include bis (methylcyclopentadienyl) zirconium dichloride (J. Chem. Soc. Dalton Trans., 805 (198)
1)), bis (pentamethylcyclopentadienyl) zirconium dichloride (J. Am. Chem. Soc., 100, 3078 (197
8)), (pentamethylcyclopentadienyl) (methylcyclopentadienyl) zirconium dichloride (J. Am.
Chem. Soc., 106, 6355 (1984)).
However, no synthesis examples of a hafnium compound having a di-substituted, tri-substituted or tetra-substituted cyclopentadienyl group as a two ligand have been reported so far.

[0004] Metallocene compounds having a substituted cyclopentadienyl group are disclosed in JP-A-60-35006, JP-A-60-35007, and JP-A-60-35.
008 and JP 61-296008 discloses the general formula _{[(C 5 R 'm)} p R''s (C 5 R' m) MeQ 3-p] and [R '' _s (C ₅ R ' _m ) ₂ MeQ] is used as a catalyst, but the synthesis method and physical properties of the compound are not described at all.

The present applicants have also disclosed Japanese Patent Publication No. 6-6264.
No. 2, Japanese Patent Publication No. 6-62643, Japanese Patent Publication No. 6-6-6
No. 2644 and Japanese Patent Publication No. 7-103185 disclose a metallocene compound having a substituted cyclopentadienyl group, but the polyolefin produced using such a conventional metallocene catalyst has a small molecular weight. Technical issues remained.

[0006]

A catalyst for efficiently producing a high molecular weight olefin polymer has been demanded.

[0007]

Means for Solving the Problems The present inventors have conducted various studies to solve the above problems, and as a result, succeeded in efficiently synthesizing a novel hafnium compound, and using the hafnium compound as a catalyst. It has been found that when used, an olefin polymer having a large molecular weight can be efficiently produced, and the present invention has been completed. A first aspect of the present invention is a metallocene compound represented by the general formula (1).

[0008]

Embedded image

In the general formula (1), (R ¹ _n -C ₅ H
_5-n) and _{^{(R 1 q -C 5 H 5}} -q) represents a substituted cyclopentadienyl group, each R ¹ independently of one another, a hydrocarbon group, each X independently of each other, A hydrogen, a halogen, or a hydrocarbon group, and n and q each represent an integer of 2 to 4] A second aspect of the present invention is that each R ¹ is an alkyl group having 1 to 5 carbon atoms. The hafnium compound according to the first aspect.

A third aspect of the present invention is that each R ¹ is n = q.
The hafnium compound according to the second aspect of the present invention. A fourth aspect of the present invention is the hafnium compound according to the second aspect of the present invention, wherein each R ¹ is n = q = 3. A fifth aspect of the present invention is the hafnium compound according to the fourth aspect, wherein each R ¹ is a methyl group.

Further, the sixth to tenth aspects of the present invention are olefin polymerization catalysts containing the metallocene compounds according to the first to fifth aspects of the present invention, respectively. The hafnium compound represented by the general formula (1) of the present invention is a novel hafnium compound having a bis-substituted cyclopentadienyl ligand. By using the hafnium compound of the present invention as a catalyst component for olefin polymerization, an olefin polymer having a large molecular weight can be efficiently produced.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION In the above general formula (1) representing the hafnium compound of the present invention, examples of the hydrocarbon group include:
Examples include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a sec-butyl group, and a tert-butyl group. Examples of halogen include fluorine, chlorine, bromine and iodine.

A typical synthetic route of the metallocene compound represented by the above general formula (1) of the present invention can be abbreviated as follows, taking n = q = 3 as an example, but is not limited thereto. .

[0014] ^{_{[1] R 1 3 -C 5}} H 3 + n-BuLi →
^{_{Li (R 1 3 -C 5 H}} 2) + C 4 H 10 [2] 2 Li (R 1 3 -C 5 H 2) + HfX 4 → (R 1 3 -C
_{5 H 2) 2 HfX 2 +} 2 LiX

[0015] The preparation of substituted cyclopentadiene compounds is known. That is, Bull. Soc. Chim. Fr., 2981 (19
70), Izv.Akad.Nauk SSSR, Ser.Khim., 1969 (197
1), Tetrahedron, 19, 1939 (1963), and J. Org.
em., 38, 4071 (1973). Such a substituted cyclopentadiene can be lithiated with an alkyl lithium as in the above reaction formula [1] and used as a lithium compound in the next reaction. Further, it can be used as a potassium compound or a sodium compound.

The reaction of MX ₄ with a lithium compound (eg, the above reaction formula [2]) can be carried out using ethers, preferably tetrahydrofuran (THF) or 1,2-dimethoxyethane (DME) as a reaction solvent. . The reaction is preferably performed in a molar ratio of lithium compound / HfX ₄ of 1.9 to 3.0, particularly 2.0 to 2.4. The reaction temperature is from −80 ° C. to 100
° C, especially in the range of 0 ° C to 70 ° C. The reaction is completed within 3 days if carried out at room temperature, but the reaction can be completed in a short time by heating. The produced metallocene compound represented by the general formula (1) can be purified by recrystallization or sublimation.

The metallocene compound of the present invention represented by the general formula (1) exhibits excellent olefin polymerization activity in the presence of an aluminoxane, an ionized ionic compound, or an ionized ionic compound and an organoaluminum compound, and exhibits a polymerization catalyst component. Is a useful compound. The aluminoxane as another catalyst component used in the polymerization is an organoaluminum compound represented by the general formula (2) or (3).

[0018]

Embedded image

[In the general formulas (2) and (3), each R ² is independently hydrogen or carbon having 1 to 20 carbon atoms.
And m represents an integer of 4 to 30.] The hydrocarbon group for each R ² has 1 to 20 carbon atoms, preferably 1 to 6 carbon atoms, more preferably 1 to 6 carbon atoms. Is 1 to 4. Specifically, a methyl group, an ethyl group,
Alkyl group such as propyl group, butyl group, isobutyl group, pentyl group, hexyl group, allyl group, 2-methylallyl group, propenyl group, isopropenyl group, 2-methyl-1-
Examples include an alkenyl group such as a propenyl group and a butenyl group, a cycloalkyl group such as a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, and a cyclohexyl group, and an aryl group.

When R ² is the same, R ² is preferably a hydrocarbon group such as a methyl group, an ethyl group, a propyl group, an isobutyl group, a phenyl group and a benzyl group, and more preferably a methyl group. When R ² is different, a combination of a methyl group and a hydrogen group or a methyl group and an isobutyl group is preferable. In these combinations, the hydrogen and the isobutyl group are 0.01 to 60% (of the total R ² It is preferably present in an amount of (number ratio).

The above aluminoxane can be prepared under various known conditions. Specifically, the following method can be exemplified. (1) A method in which a trialkylaluminum is directly reacted with water using an organic solvent such as toluene or ether. (2) A method of reacting a trialkylaluminum with a salt having water of crystallization, such as copper sulfate hydrate or aluminum sulfate hydrate. (3) A method of reacting trialkylaluminum with water impregnated in silica gel or the like. (4) A method in which trimethylaluminum and triisobutylaluminum are mixed and directly reacted with water using an organic solvent such as toluene or ether. (5) A method in which trimethylaluminum and triisobutylaluminum are mixed and reacted with a salt having water of crystallization, for example, copper sulfate hydrate or aluminum sulfate hydrate. (6) A method in which silica gel or the like is impregnated with water, triisobutylaluminum is reacted, and trimethylaluminum is further reacted.

The ionized ionic compound is a compound represented by the following general formula (4). ^{[C +] [A -]} ····· (4)

In the general formula (4), [C ⁺ ] is a cation, some of which have an active proton and some of which do not. Specifically, those containing active protons include trimethylammonium, triethylammonium, tripropylammonium, tributylammonium, N, N-dimethylanilinium, N, N, 2,4,5-pentamethylanilinium, Phenylphosphonium, tri (o-
(Tolyl) phosphonium, tri (p-tolyl) phosphonium,
Examples include Bronsted acids represented by tri (mesityl) phosphonium and the like. Examples of those not containing an active proton include carbonium, oxonium and sulfonium cations.Examples of these include compounds represented by triphenylcarbenium and tripyllium ions. It is not limited.

Further, [A ^-] is an anion is not particularly limited ^{_{[AlR 4 -], [BR}} 4 -], [PR 6 -] [C
lO ₄ ^-] and the like can be exemplified. Here,
R is methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, t-butyl, n-pentyl, isopentyl, sec-pentyl, t-pentyl A C ₁ -C ₂₀ hydrocarbon group such as a group, hexyl group, heptyl group, octyl group, nonyl group, decyl group, phenyl group, benzyl group, and naphthyl group.

Further, a C ₁ -C ₁₀ hydrocarbon group or a halogen substituent may be introduced into R.
Specifically, a methylphenyl group, a dimethylphenyl group,
Trimethylphenyl, hexamethylphenyl, pentamethylphenyl, ethylphenyl, butylphenyl, pentylphenyl, chlorophenyl, dichlorophenyl, trichlorophenyl, hexachlorophenyl, pentachlorophenyl, bromophenyl, dibromophenyl Group, tribromophenyl group, hexabromophenyl group, pentabromophenyl group, fluorophenyl group, difluorophenyl group, trifluorophenyl group, hexafluorophenyl group, pentafluorophenyl group and the like.

The organoaluminum compound is a compound represented by the following general formula (5). R ³ _S AlY _3-S・ ・ ・ ・ ・ （５）

In the general formula (5), R ³ has 3 to 3 carbon atoms.
12 represents a hydrocarbon group, Y represents hydrogen or halogen, and s represents an integer of 1 to 3. Examples of the hydrocarbon group for R ⁴ include an alkyl group and an alkenyl group such as a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group and a t-butyl group. The halogen in Y is fluorine, chlorine, bromine and the like.

The olefins which can be used as the catalyst for the polymerization reaction of the metallocene compound of the present invention include propylene, 1-butene, 4-methyl-1-pentene, 1-hexene and 1-hexene.
Α-olefins such as octene, and a mixture of two or more of these components can be used for polymerization. Further, copolymerization of the above-mentioned α-olefins with ethylene is also possible.
Further, conjugated and non-conjugated dienes such as butadiene, 1,4-hexadiene, 1,4-pentadiene, and 1,7-octadiene, and cyclic compounds such as styrene, cyclopropane, cyclobutene, norbornene, dicyclopentadiene, and the like. It is also effective for the copolymerization of α-olefins with polar vinyl monomers such as olefins, acrylic esters and methacrylic esters.

The polymerization reaction using the metallocene compound of the present invention as a catalyst can be either liquid phase polymerization or gas phase polymerization. As a polymerization solvent for liquid phase polymerization, a hydrocarbon compound capable of dissolving a hafnium compound, such as benzene, toluene, o-xylene, m-xylene, p-xylene, ethylbenzene, butylbenzene, mesitylene, and an aromatic solvent such as naphthalene Hydrocarbons are used, preferably toluene,
Xylene.

Further, the applicant of the present invention disclosed in Japanese Patent Publication No. Hei 7-96566.
As disclosed in Japanese Patent Application Publication No. H07-27, even in a solvent in which a hafnium compound cannot be dissolved, a hafnium compound and an aluminoxane, an ionized ionic compound, or both components of an ionized ionic compound and organic aluminum are contained in an aromatic hydrocarbon. If the catalyst is preliminarily mixed and reacted with a small amount of α-olefin to be preactivated, a polymerization reaction can be carried out.

Examples of the solvent used herein include aliphatic hydrocarbons such as butane, isobutane, pentane, hexane, octane, decane, dodecane, hexadecane and octadecane, and alicyclic rings such as cyclopentane, methylcyclopentane, cyclohexane and cyclooctane. Examples include petroleum fractions such as aliphatic hydrocarbons, gasoline, kerosene, and light oil, with aliphatic hydrocarbons being preferred. Furthermore, liquefied propylene as a raw material,
Liquefied olefins such as liquefied 1-butene can also be used as the solvent.

As the catalyst component, a hafnium compound, an aluminoxane, an ionized ionic compound, or a mixture of both components of the ionized ionic compound and aluminum in advance may be supplied to the reaction system. The two components may be separately supplied. The amount of each catalyst component used is, for example, when aluminoxane is used, 10 to 100 aluminum atoms in the aluminoxane are used per mole of the transition metal atom in the hafnium compound.
000 mol, preferably 50 to 50,000 mol, particularly preferably 100 to 30,000 mol.

The polymerization temperature of the reaction system using the hafnium compound of the present invention is not particularly limited, but is preferably -50.
C. to 150.degree. C., particularly preferably -10.degree. C. to 100.degree. The polymerization pressure is not particularly limited, but is preferably from atmospheric pressure to 7 MPa, particularly preferably 0.2 MPa.
It is performed in the range of ５5 MPa. The molecular weight at the time of the polymerization reaction at this time can be adjusted by known means, for example, by selecting a polymerization temperature or introducing hydrogen.

The olefin polymerization catalyst of the present invention may contain the hafnium compound of the present invention at an arbitrary ratio. The higher the ratio of the hafnium compound of the present invention to the total catalyst, the more remarkable the effect of the present invention. appear.

[0035]

Next, the present invention will be described specifically with reference to examples.

Example 1 [Synthesis of bis (1,2,4-trimethylcyclopentadienyl) hafnium dichloride: In the general formula (1), n = q = 3 and each R ¹ is a methyl group. Compound in which each X is All Chlorine] All the reactions were performed under an inert gas atmosphere. The reaction solvent used was dried in advance. In a 100 ml glass reaction vessel, 2.16 g (20.00 mmol) of 1,2,4-tridimethylphenylcyclopentadiene was dissolved in 50 ml of tetrahydrofuran (THF), and 1.57 g of n-butyllithium was dissolved.
13 ml (20.41 mmol) of a M hexane solution was added dropwise at -78 ° C.
After returning to room temperature and stirring for 16 hours, a white-yellow suspension was obtained. The solvent was distilled off under reduced pressure, methylene chloride (20 ml) was added to suspend the mixture, and the mixture was coagulated in a liquid nitrogen bath.Furthermore, a suspension of 3.32 g (10.00 mmol) of hafnium tetrachloride in 20 ml of methylene chloride was added and coagulated. I let it. After gradually warming to room temperature, the mixture was stirred for 20 hours to obtain a milky suspension. The insoluble solid was filtered through a membrane filter having a pore size of 0.5 mm, and the solvent was distilled off under reduced pressure and dried to obtain a yellow-white powder.
By recrystallization from toluene / hexane, 2.60 g (56% yield) of colorless columnar crystals were obtained. The physical properties of this compound are shown below. The 1H-NMR spectrum was measured using CDCl3 as a solvent. Elemental analysis: (C ₁₆ H ₂₂ Cl ₂ Hf) Calculated (%): C; 41.44, H; 4.78 Found (%): C; 37.67, H; 4.33 NMR spectrum: shown in FIG. From these results, the target compound was identified.

Example 2 [Polymerization] After replacing a 1.5-L internal volume stainless steel polymerization apparatus equipped with a stirrer with a stirrer with nitrogen gas, 500 ml of purified toluene and a toluene solution of methylaluminoxane (Tosoh Akzo Co., Ltd.) were placed in the polymerization apparatus. (Product name: MMAO, Al concentration: 2mol / l)
Is 15 mmol in terms of Al atomic weight, bis (1,2,4-trimethylcyclopentadienyl) hafnium dichloride 0.0015 mmol
Was sequentially added, and the temperature was raised to 30 ° C. Subsequently, propylene was continuously introduced so that the pressure inside the polymerization vessel was maintained at 0.3 MPa, and a polymerization reaction was performed for 1 hour. After completion of the polymerization, unreacted propylene was discharged from the polymerization vessel, and methanol was added to decompose the catalyst component. As a result, 24 g of atactic polypropylene was obtained, and the catalytic activity was 16.2 × 10 ⁶ g / molHf · hr. The weight average molecular weight (Mw) of the polymer is 640.
000.

Comparative Example 1 [Polymerization] After replacing a 1.5 L internal volume stainless steel polymerization vessel equipped with a stirrer equipped with a stirrer with nitrogen gas, 450 ml of purified toluene was placed in the polymerization vessel, manufactured by Toyo Stouffer Chemical Co., Ltd. 6.3mmo of toluene solution of methylaluminoxane in terms of Al atomic weight
l and a solution of bis (1,2,4-trimethylcyclopentadienyl) zirconium dichloride in 0.02 mmol of toluene were sequentially added, and the temperature was raised to 50 ° C. Subsequently, the pressure in the polymerization vessel was 0.8 M
Propylene is continuously introduced so as to maintain Pa.
The polymerization reaction was performed for 5 hours. After completion of the polymerization, unreacted propylene was discharged from the polymerization vessel, and methanol was added to decompose the catalyst component. As a result, 260 g of atactic polypropylene was obtained, and the catalytic activity was 9.1 × 10 5
^{It was 6} g / mol Zr · hr. The weight average molecular weight (Mw) of the polymer was 12,600.

[0039]

According to the present invention, a novel hafnium compound having a substituted cyclopentadienyl ligand was obtained. When these hafnium compounds are used as catalysts for olefin polymerization, high-molecular-weight olefin polymers can be efficiently produced and are industrially useful.

[Brief description of the drawings]

FIG. 1 is a ¹ H-NMR spectrum of a compound synthesized in Example 1.

Claims (10)

[Claims] 1. A hafnium compound represented by the following general formula (1). Embedded image [In the general formula _{^{(1), (R 1 n}} -C 5 H 5-n) and ^{_{(R 1 q -C 5 H 5}} -q) represents a substituted cyclopentadienyl group, each R ¹ is independently from each other Represents a hydrocarbon group, and each X
Each independently represents a hydrogen, halogen, or hydrocarbon group, and n and q each represent an integer of 2 to 4] 2. The hafnium compound according to claim 1, wherein each R ¹ is an alkyl group having 1 to 5 carbon atoms. 3. The hafnium compound according to claim 2, wherein n = q. 4. The hafnium compound according to claim 2, wherein n = q = 3. 5. The hafnium compound according to claim 4, wherein each R ¹ is a methyl group. 6. An olefin polymerization catalyst comprising the hafnium compound according to claim 1. 7. An olefin polymerization catalyst comprising the hafnium compound according to claim 2. 8. An olefin polymerization catalyst comprising the hafnium compound according to claim 3. 9. An olefin polymerization catalyst comprising the hafnium compound according to claim 4. 10. An olefin polymerization catalyst comprising the hafnium compound according to claim 5. Description: