JP3213774B2 - Hafnium compounds having asymmetric ligands and catalyst components - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel hafnium compound having a bridging ligand having an asymmetric substituent. The compound of the present invention is effective as a catalyst component for stereoregular olefin polymerization.

[0002]

2. Description of the Related Art Kaminski catalysts (metallocene / methylalumoxane) are widely known as homogeneous catalysts for olefin polymerization. This catalyst system is characterized by a remarkably high activity per transition metal. Recently, it has been known that stereospecific polymerization is possible in the polymerization of α-olefins (mainly propylene). For example, atactic polypropylene (Makromol. Chem., Rapid Com.
mun. 4, 417-421 (1983), JP-A-58-19309), isotactic polypropylene (Angew. Chem. Int. Ed.
Engl., 24, 507-508 (1983), J. Am. Chem. Soc., 106, 6355 (198
4), J. Am. Chem. Scc., 109, 6544 (1987), Chem. Lett., 1853-1.
856 (1989), JP-A-2-76887)), syndiotactic polypropylene (J. Am. Chem. Soc., 110, 6255, (198)
8)) and the like can be produced. The key to the expression of these stereospecificities is the ligand structure and the stereostructure of the zirconium complex. However, zirconium compounds that can produce industrially important isotactic polypropylene include Et (Ind) ₂ ZrCl ₂ and Me ₂ Si (2,3,5-Me ₃ C
_{5 H) (2 ', 4} ', 5'-Me 3 C 5 H) , such as ZrCl _2, there is only like having C2 symmetry in the molecule, stereospecificity and molecular weight of the resulting polymer is sufficiently In addition, purification was extremely difficult due to the formation of isomers in the synthesis.

[0003]

The problem to be solved by the present invention is to synthesize a novel hafnium compound which does not cause the problems in the prior art as described above, and to provide a useful catalyst component for stereospecific olefin polymerization. It is to provide.

[0004]

Means for Solving the Problems The present inventors have made intensive studies to solve the above problems, and as a result, have succeeded in efficiently synthesizing the following novel hafnium compounds, and The present inventors have found that the compound is useful as a catalyst component for stereospecific olefin polymerization, and have completed the present invention. That is, a hafnium compound having an asymmetric ligand represented by the general formula (1)

Embedded image [In formula (1), X ¹ and X ² may be the same or different and each represent a hydrogen atom, a hydrocarbon group having 1 to 10 carbon atoms, an alkylsilyl group, or a halogen atom. R ³ , R ² and R ¹ represent a hydrogen atom, a hydrocarbon group having 1 to 10 carbon atoms, an alkylsilyl group or an arylsilyl group, and one of R ² and R ³ is a hydrogen atom.
R ⁴ represents a hydrogen atom, a hydrocarbon group having 1 to 10 carbon atoms, or an alkylsilyl group or an arylsilyl group. And the catalyst component for olefin polymerization containing this compound as an active ingredient.

Hereinafter, the present invention will be described in detail. Equation (1)
Is a novel hafnium compound having a bridging ligand having an asymmetric substituent. One of the substituents R ² and R ³ at the position specified in the formula (1) on the cyclopentadienyl ring of the hafnium compound of the present invention is a hydrocarbon group having 1 to 10 carbon atoms (alkyl, allyl). , Alkylaryl, arylalkyl, etc.) or an alkylsilyl group, an arylsilyl group, etc., and more preferably a bulky substituent such as a tert-butyl group. However, one of R ² and R ³ needs to be a hydrogen atom.

A typical synthetic route of the compound (1) of the present invention is abbreviated as shown in Scheme 1 below, but is not limited thereto. Scheme 1 Hafnium compound having substituent on cyclopentadienyl ring

Embedded image

Here, a method for producing a bis-substituted cyclopentadienyl bridge type bidentate ligand having a crosslinked structure is known. That is, J.I. Am. Chem. Soc. , 110,97
6-978 (1988); Am. Chem. So
c. , 107, 8103-8110 (1985). Such a bidentate ligand can be lithiated with alkyllithium and used as a lithium compound in the next reaction. It can also be used as a potassium or sodium compound. HFX ₄ (X is a halogen atom) reaction of a lithium compound for _{example, Li 2 [iPr (tBu-} C 5 H 3) (C 9 H 5 -tBu)] + HfCl 4 --- → iPr (tBu-C 5 _{H 3) (C 9 H5 5} -tBu) HfCl 2 which are ethers preferably can be carried out in tetrahydrofuran as the reaction solvent. Further, the reaction can be carried out using methylene chloride as a reaction solvent. The reaction is preferably carried out at a molar ratio of lithium compound to HfX ₄ in the range of 1.0 to 1.5, especially 1.0 to 1.1. The reaction temperature is preferably in the range of -80C to 100C, especially -20C to 88C. The produced hafnium compound can be purified by recrystallization.

As examples of the hafnium compound, the following metallocene compounds can be exemplified. At that time, the names of the metallocene compounds were named according to the following definitions. (Definition: The number indicating the position of a substituent on cyclopentadienyl is as follows: in formula (1), R ¹ is 3-position on the indene ring, R ¹ is
² and R ³ are such that R ² is 4-position on the cyclopentadiene ring, R ³
Ranks third. ) Isopropylidene (4-methyl-cyclopentadienyl) (3-methyl-indenyl) hafnium dichloride, isopropylidene (4-tbutyl-cyclopentadienyl) (3-methyl-indenyl) hafnium dichloride, isopropylidene (4 -Tbutyl-cyclopentadienyl) (3-tbutyl-indenyl) hafnium dichloride, dimethylsilylene (4-methyl-cyclopentadienyl) (3-methyl-indenyl) hafnium dichloride, isopropylidene (4-methyl-cyclo Pentadienyl) (3-methyl-indenyl) hafnium dimethyl, isopropylidene (4-tbutyl-cyclopentadienyl) (3-methyl-indenyl) hafnium dimethyl, isopropylidene (4-tbutyl-cyclopentadienyl) (3- t-butyl-indenyl) hafnium dimethyl and the like. In the above examples, (4-methyl-cyclopentadienyl) may be substituted with (3-methyl-cyclopentadienyl). The hafnium compound according to the present invention exhibits excellent olefin polymerization activity in the presence of aluminoxane or in the presence of a quaternary boron anion that effectively stabilizes the Hf cation, and is a compound useful as a polymerization catalyst component.

Aluminoxane as another catalyst component used in the polymerization is represented by the general formula (2) or (3):
Is an organoaluminum compound represented by General formula (2)

Embedded image

Embedded image Is an organoaluminum compound represented by R ⁵ is
It is a hydrocarbon group such as a methyl group, an ethyl group, a propyl group, a butyl group and an isobutyl group, and is preferably a methyl group. m is an integer from 4 to 100, preferably 6
It is more than 10 especially. The method for producing this kind of compound is known, for example, a method for obtaining a salt having water of crystallization by adding a trialkylaluminum to a hydrocarbon solvent suspension of (copper sulfate hydrate, aluminum sulfate hydrate). You can do it.

In the method of the present invention, the olefin used for the polymerization is ethylene, propylene, 1-butene, 2-olefin.
Examples include olefins such as butene, 1-pentene, 4-methyl-1-pentene, cyclopentene, norbornene, cyclopentadiene, butadiene, 1,5-hexadiene and 1,4-hexadiene, cyclic olefins, and dienes. I can do it. It is also possible to polymerize a mixture of two or more of these components. The polymerization method used in the present invention can be either liquid phase polymerization or gas phase polymerization. Solvents for liquid phase polymerization are hydrocarbon compounds capable of dissolving both zirconium compounds and aluminoxane components, such as benzene, toluene, o-xylene, m-xylene, p-xylene, ethylbenzene, butylbenzene, mesitylene, chlorobenzene, etc. Are used, and toluene and xylene are preferable.

The hafnium compound of the present invention is supported on a carrier such as silica, alumina or magnesium chloride, or by prepolymerizing an olefin.
It can be used in a solvent or a monomer which cannot dissolve both the hafnium compound and the aluminoxane component. As the catalyst component, a mixture of both the hafnium compound and the aluminoxane in advance may be supplied to the reaction system, or both components may be supplied to the reaction system. In any case, the molar concentration ratio of both components in the polymerization system is not particularly limited, but preferably, the Hf concentration is 10%.
^-3 to 10 ^-10 mol / l, and a molar ratio of Al / Hf of 10 or more, particularly 100 or more is preferably used. There is no particular limitation on the olefin pressure of the reaction system,
It is preferably in the range of normal pressure to 50 kg / cm ² G, and the polymerization temperature is not limited, but is preferably in the range of -30 ° C to 100 ° C. The molecular weight at the time of polymerization can be adjusted by known means, for example, by selecting a temperature or introducing hydrogen.

[0012]

Next, the present invention will be described specifically with reference to examples. The analytical instruments used for measuring the physical properties are as follows. ¹ H-NMR JEOL EX-400 mass spectrometer JEOL JMS-AX500 IR Perkin Elmer 5150 Example 1 [Isopropylidene (4-tbutyl-cyclopentadienyl) (3-tbutylindenyl) ) Hafnium dichloride] reactions were all performed under an inert gas atmosphere. In addition, the reaction vessel used was previously dried.
100 ml of dry THF was put into a 300 ml glass reaction vessel, and 3.5 g of dimethyl (3-tbutylcyclopentadienyl) (3-tbutylindenyl) methane was dissolved therein, and 1 g of NaH (washed with hexane) was added. After heating under reflux for 24 hours. Excess NaH was filtered off.
Meanwhile, 3.4 g of hafnium tetrachloride (purity: 99.99%) was charged into a separately prepared flask, and THF5 was added.
0 ml was added and suspended. This is followed by dimethyl (3-t
A THF solution of sodium salt of butylcyclopentadienyl) (3-tBuindenyl) methane was added via cannula at room temperature. After reacting at room temperature for 2 hours, THF was distilled off under reduced pressure, and toluene-insoluble sodium chloride was removed by toluene extraction. The solution was concentrated to give pale yellow crystals. Yield 0.8 g Physical properties of this compound are shown below. In addition, IR spectrum is KBr method, ¹ H-NMR spectrum is CDCl ₃
Was measured using as a solvent. The Mass spectrum is
It was measured by the direct introduction method. Elemental _{analysis: (C 25 H 32 HfCl 2} ) Calculated (%): C; 51.60, H; 5.54 Found (%): C; 51.32, H; 5.27 IR spectrum: FIG. It is shown in FIG. NMR spectrum: shown in FIG. Mass spectrum: shown in FIG.

Example 2 [Polymerization] 1.5 liters of sulfur sufficiently purged with nitrogen
300 ml of purified toluene was added to a US autoclave. Methylaluminoxane manufactured by Tosoh Akzo (2. per aluminum)
36M) and 0.2 mmol of isopropylidene (4-tbutylcyclopentadienyl) (3-tbutylindenyl) hafnium dichloride were sequentially added, and the mixture was cooled to 3 ° C. Then, 2 mol of propylene was charged and polymerization was carried out for 1 hour. After the reaction, the catalyst component was decomposed with methanol and the obtained polypropylene was dried. As a result, 6 g of high isotactic polypropylene was obtained. The molecular weight of the polymer was 60000 in Mw.

Example 3 [Isopropylidene (3-tbutylcyclopentadienyl) (3-methylindenyl) hafnium dichloride]
All reactions were performed under nitrogen. 60 ml of dry THF was charged into a 300 ml glass reaction vessel, and 2.68 g of dimethyl (t-butylcyclopentadienyl) (methylindenyl) methane was dissolved therein. 13 m of 1.6 mol / l n-Bu.Li hexane solution at 0 ° C.
and stirred at room temperature for 2 hours. On the other hand, hafnium tetrachloride (99.99%) was added to a separately prepared flask with TH.
It was suspended in 50 ml of F. This is followed by dimethyl (3-tbutylcyclopentadienyl) (3-methylindenyl)
A solution of lithium salt of methane in THF was added. After reacting at room temperature for 1 hour, THF was distilled off, and then extracted with toluene to remove lithium chloride. The toluene solution was concentrated to obtain pale yellow crystals. (Yield 0.5 mg) Physical properties of this compound are shown below. The ¹ H-NMR spectrum was measured using CDCl ₃ as a solvent. Also M
The ass spectra were measured by the direct introduction method. Elemental _{analysis: (C 22 H 26 HfCl 2} ) Calculated (%): C; 48.95, H; 4.77 Found (%): C; 48.70, H; 4.51 NMR Spectrum: Figure It is shown in FIG. Mass spectrum: shown in FIG.

Example 4 [Polymerization] 1.5 liter of internal volume of S sufficiently purged with nitrogen
300 ml of purified toluene was added to a US autoclave. Methylaluminoxane manufactured by Toso-Akzo (2.
36M) and 0.2 mmol of isopropylidene (3-tbutylcyclopentadienyl) (3-methylindenyl) hafnium dichloride were added successively, and 3 ° C.
And cooled. Then, 2 mol of propylene was charged and polymerization was carried out for 1 hour. After the reaction, the catalyst component was decomposed with methanol and the obtained polypropylene was dried. As a result, 8 g of high isotactic polypropylene was obtained. The molecular weight of the polymer was 80,000 in Mw.

[0016]

According to the present invention, a novel hafnium compound having a bridging ligand having an asymmetric substituent can be obtained. If these hafnium compounds are used as olefin polymerization catalyst components in olefin polymerization, stereospecific polymers can be produced efficiently.

[Brief description of the drawings]

FIG. 1 is an IR spectrum of the hafnium compound of the present invention.

FIG. 2 is a ¹ H-NMR spectrum of the hafnium compound of the present invention.

FIG. 3 is a Mass spectrum of the hafnium compound of the present invention.

FIG. 4 is a ¹ H-NMR spectrum of the hafnium compound of the present invention.

FIG. 5 is a Mass spectrum of the hafnium compound of the present invention.

Continuation of the front page (56) References UK Patent Application Publication 2241244 (GB, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) CA (STN) CAOLD (STN) REGISTRY (STN)

Claims (4)

(57) [Claims] 1. A hafnium compound having an asymmetric ligand represented by the general formula (1). Embedded image [In formula (1), X ¹ and X ² may be the same or different and each represent a hydrogen atom, a hydrocarbon group having 1 to 10 carbon atoms, an alkylsilyl group, or a halogen atom. R ³ , R ² and R ¹ represent a hydrogen atom, a hydrocarbon group having 1 to 10 carbon atoms, an alkylsilyl group or an arylsilyl group, and one of R ² and R ³ is a hydrogen atom.
R ⁴ represents a hydrogen atom, a hydrocarbon group having 1 to 10 carbon atoms, or an alkylsilyl group or an arylsilyl group. ] 2. R ¹ is a methyl or t-butyl group, R ² is a t-butyl group, R ³ is a hydrogen atom, R ⁴ is a methyl group, X ¹
And the compound of claim 1, wherein X ² is halogen. 3. R ¹ is a methyl or t-butyl group, R ³ is a t-butyl group, R ² is a hydrogen atom, R ⁴ is a methyl group, X ¹
And the compound of claim 1, wherein X ² is halogen. 4. An olefin polymerization catalyst component comprising the compound of the formula (1) according to claim 1 as an active ingredient.