JPH03195706A - Production of syndiotactic poly-alpha-olefin - Google Patents

Abstract

PURPOSE:To obtain the subject poly-alpha-olefin having high activity and syndiotacticity in high productivity by polymerizing an alpha-olefin using a catalyst comprising a specific transition metal compound and aluminoxane. CONSTITUTION:An alpha-olefin is polymerized using a catalyst composed of (A) a compound of transition metal of IV-B group in the periodic table [e.g., cyclohexylidene (cyclopentadienyl-fluorenyl)titanium dimethyl] containing cycloalkylidene (cyclopentadienyl-1-fluorenyl) group as a ligand and (B) aluminoxane (preferably methyl aluminoxane) to afford the aimed polymer.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for producing syndiotactic poly-α-olefins using a novel highly active polymerization catalyst. Specifically, the present invention relates to a method for producing syndiotactic poly-α-olefin in the presence of a catalyst consisting of a specific transition metal compound and aluminoxane.

[Conventional technology]

It has been known for a long time that syndiotactic poly-α-olefins, especially syndiotactic polypropylene, can be obtained by low-temperature polymerization using a catalyst consisting of a vanadium compound and an organoaluminum. It was difficult to say that the syndiotacticity of the poly-α-olefin was indicative of the characteristics of a true syndiotactic poly-α-olefin.

On the other hand, J, ^, EWEN et al. reported that a syndiotactic pentad fraction exceeds 0.8 using a catalyst consisting of a transition metal compound having an isopropylidene (cyclopentadienyl-fluorenyl) group as a ligand and aluminoxane. It was discovered for the first time that polypropylene with good toughness such as (J, Aa+, Ch
em, Soc, , 198B, 110.6255-
6256).

A catalyst consisting of a transition metal compound having a fluorenyl group as a ligand and aluminoxane similar to that of J. There is no description of a transition metal compound in which a compound to which a fluorenyl group is bonded is used as a ligand.As disclosed in JP-A-64-66214, a transition metal compound in which a fluorenyl group is bonded to a transition metal and aluminoxane are used as catalysts. Even if α-olefin is polymerized using the catalyst system of the present invention, the syndiotactic poly-α-olefin produced by the catalyst system of the present invention cannot be obtained, but is a completely different catalyst system.

[Problem that the invention seeks to solve]

The method by J. A. EWEN et al. has good activity per transition metal, and the resulting polymer has high gingioctality. However, the catalyst is unstable and the transition metal catalyst and aluminoxane are mixed. Mixtures of these substances had the problem that their activity decreased over time.

[Means for Solving the Problems] The present inventors have conducted intensive studies on a method for solving the above problems and producing poly-α-olefins with high activity and high gingioctality with high productivity, and have developed the present invention. I have reached the point where I have completed the .

That is, the present invention provides (A) a transition metal compound and (B)
In a method for polymerizing α-olefin using a catalyst consisting of aluminoxane, (A) as a transition metal compound,
This is a method for producing a syndiotactic poly-α-olefin, which is characterized by using a transition metal compound of Group IVB of the periodic table having a cycloalkylidene (cyclopentadienyl-1-fluorenyl) group as a ligand.

The transition metal compound of the TVB group of the periodic table having a cycloalkylidene (cyclopentadienyl-1-fluorenyl) group as a ligand used in the present invention has the general formula % (where AI is cyclopentadienyl-1-fluorenyl). Jenyl group, A2 represents a fluorenyl group, A3 represents a cycloalkylidene group having 4 to 10 carbon atoms, and R1 and R2 represent an aryl group, an alkyl group, a cycloalkyl group, or a halogen atom, a hydrogen atom, or a silyl group. The group 0M is titanium, zirconium, or haunium).

Specific examples of the above transition metal compounds include cyclohexylidene (cyclopentadienyl-fluorenyl) titanium dimethyl, cyclohexylidene (cyclopentadienyl-fluorenyl) zirconium dimethyl, and cyclohexylidene (cyclopentadienyl-fluorenyl). Hafnium dimethyl, cyclocylidene (cyclopentadienyl-fluorenyl) titanium diphenyl, cyclohexylidene (cyclopentadienyl-fluorenyl) zirconium diphenyl, cyclohexylidene (cyclopentadienyl-fluorenyl) hafnium diphenyl, cyclohexylidene (cyclopentadienyl-fluorenyl) enyl-fluorenyl) titanium dichloride, cyclohexylidene (cyclopentadienyl-fluorenyl) zirconium dichloride, cyclohexylidene (cyclopentadienyl-fluorenyl) hafnium dichloride, cycloalkylidene (cyclopentadienyl-fluorenyl) zirconium dichloride, cyclopent tenylidene (cyclopentadienyl-fluorenyl) hafnium dichloride,
Examples include cycloalkylidene (cyclopentadienyl-fluorenyl) zirconium dichloride.

Among the catalysts used in the present invention, the aluminoxane which is the component (B) has the following formula: The compound represented by the formula is particularly methylaluminoxane in which R is a methyl group, where n is 5 or more, preferably 10 or more.

The above-mentioned method for producing aluminoxane is publicly known, such as a method in which trialkylaluminum is added to salts containing water of crystallization (copper sulfate hydrate, magnesium chloride hydrate, etc.) in a hydrocarbon solvent and reacted. Alternatively, a method of directly reacting trialkylaluminum and water in a breeding compound solvent can be exemplified.

The above catalyst components (A) and/or (B) may be used as they are,
It may be used by being supported on a known carrier that supports a Ziegler type catalyst.

The ratio of aluminoxane used to the transition metal catalyst is 10 to 1000 times, usually 50 to 5000 times. In the present invention, α supplied during polymerization
- Specific examples of olefins include propylene, 1-butene, 1-hexene, 1-methyl-1-pentene, 1-oftene, 1-decene, l-dodecene, 1-tetradecene, 1-hexadecene, l-octadecene. carbon number 3, such as
~25 α-olefins may be mentioned.

In the present invention, as long as α-olefin homopolymerization as well as syndiotactic structure is exhibited, for example, propylene and ethylene, propylene and 1-butene, etc.
It can also be used to produce copolymers of ethylene or α-olefins with a molecular weight of about 25%.

Examples of hydrocarbon media used in polymerization or copolymerization include saturated hydrocarbons such as butane, pentane, hexane, heptane, octane, nonane, decane, cyclopenkune, and cyclohexane, as well as aromatic carbons such as benzene, toluene, and xylene. Hydrogen and the raw material α-olefin can also be used.

There are no particular restrictions on the polymerization conditions, and solvent polymerization methods (suspension polymerization, solution polymerization) using an inert hydrocarbon medium, bulk polymerization methods in which polymerization is performed in the absence of substantially an inert hydrocarbon medium, and gas polymerization methods are available. Phase polymerization methods can also be used.

The polymerization temperature is generally 100 to 200°C, and the polymerization pressure is normal pressure to 100 kg/cill, preferably 150 to 100°C, normal pressure to 50 kg/ci.
It is.

〔Example〕

The method of the present invention will be explained below by way of examples.

Example 1 Synthesis of transition metal compound [Preparation of cyclohexylidene (cyclopentadiene-1 fluorene)] In a 300-glass flask that was sufficiently purged with nitrogen, 11.4 g (68.4 mmol) of fluorene was added to 150 mj of tetrahydrofuran! It was dissolved in To this solution, 70 mmol of an ether solution of methyllithium was added dropwise at -78°C. After the completion of the dropwise addition, the reaction solution was raised to room temperature,
The mixture was stirred at the same temperature for 3 hours. Add 50ml of tetrahydrofuran to this reaction solution! 10 g of 6,6-pentamethylenefulvene diluted with U, Org, Chem,.

19B4, 49.1849-1853) was added dropwise, the reaction temperature was raised to room temperature, and stirring was continued for an additional 10 hours. The reaction was stopped by charging 200 ml of 3.6% hydrochloric acid water, and the ether layer was washed with water and evaporated to dryness to obtain a yellowish white solid. By washing this solid with 100 d of acetone, 12.4 g of white cyclohexylidene (cyclopentadiene-1-fluorene) was obtained.

[Preparation of cyclohexylidene (cyclopencdienyl=1-fluorenyl) zirconium dichloride] By lithiation of the above-prepared cyclohexylidene (cyclopentadiene-1-fluorene) with n-butyllithium, cyclohexylidene ( A dilithium salt of cyclopentadiene-1-fluorene was prepared. In a 500 d glass flask that was sufficiently purged with nitrogen, 5.5 g of zirconium tetrachloride was suspended in 100 Id of methylene chloride. To this suspension was added 300 mff1 of a methylene chloride solution of cyclohexylidene (cyclopentadienyl-1-fluorenyl) dilithium dissolved at -78°C.
It was introduced in C. After stirring at -78°C for 4 hours, the temperature was raised to room temperature, and the reaction was continued at that temperature for an additional 15 hours. The reddish-brown solution containing a white precipitate of lithium chloride was filtered, the reddish-brown filtrate was concentrated, and the red-brown filtrate was cooled for 24 hours at -30°C to obtain red crystalline cyclohexylidene (cyclopeftagenyl-1-fluorenyl). Zirconium dichloride 2.
3g was obtained.

[Preparation of catalyst mixture]

After purging a 100 mρ glass flask with nitrogen, cyclohexylidene (cyclopentadienyl-1-fluorenyl) zirconium dichloride 10 synthesized in Example 1 was added.
+ng to 10ml of toluene? I made them understand 8.

Add methylaluminoxane 1 manufactured by Tosoh Akzo ■ to this solution.
．． A purple catalyst solution was prepared by adding 2 g.

[Polymerization method]

After replacing the autoclave No. 21 with nitrogen, add 1 g of toluene.
The catalyst solution prepared in Example 2 was added in an amount of 0.0046 mmol in terms of Zr atoms. Polymerization was carried out at 20°C for 2 hours while adding propylene to maintain the system at 3 kg/crA. After polymerization, the slurry was taken out, filtered and dried to obtain 98.5 g of gingiotactic polypropylene. In addition, even if the filtrate is distilled off under reduced pressure to remove the solvent,
The amount of components soluble in toluene was 0.1 g. The intrinsic viscosity (hereinafter abbreviated as η) of the powder measured in a tetralin solution at 135°C is 1.45 a/g, and the syndiotactic pentad content measured from the area fraction of the 20.24 ppm peak by C-NMR. The ratio was 0.90.

When the above catalyst mixture was stored at room temperature for 24 hours and polymerized in the same manner, the resulting polymer had a toluene insoluble content of 95.3 g and a) toluene soluble content of 0.1 g. The results were the same as those obtained by polymerization immediately after the polymerization.

Comparative Example 1 [Catalyst Preparation] Isopropylidene (cyclopentadiene-1-fluorene) synthesized according to a conventional method was lithiated and reacted with zirconium tetrachloride to produce isopropylidene (
10 mg of cyclopentadienyl-1-fluorenyl)zirconium dichloride was combined and dissolved in 10 d of toluene.

this? A purple catalyst solution was prepared by adding 1.3 g of methyl J-realuminutoxane to the 8 liquid.

[Polymerization method] Polymerization was carried out in the same manner as in Example 10 [Polymerization method] except that the catalyst mixture prepared above was used. The obtained polymer had a toluene soluble content of 101.6 g) and a toluene insoluble content of 2.3 g.
Met. The powder η is 1.38 cllffi/g,
The syndiotactic pentad fraction was 0.91.

However, when the catalyst mixture was stored at room temperature for 24 hours and then used as in Example 1, the resulting polymer had a toluene insoluble content of 15.0 g and a toluene soluble content of 0.4 g. As described above, the catalyst is extremely unstable compared to the catalyst of Example 1.

(Effects of the Invention) By carrying out the method of the present invention, syndiotactic poly-α-olefin can be produced with stable performance, and is extremely valuable industrially.

Procedural amendment (voluntary) March 1990 Tabi

Claims (1)

[Scope of Claims] A method of polymerizing an α-olefin using a catalyst consisting of (A) a transition metal compound and (B) aluminoxane, wherein (A) the transition metal compound is cycloalkylidene (cyclopentadienyl-1-fluorenyl). ) A method for producing a syndiotactic poly-α-olefin, the method comprising using a transition metal compound of group IVB of the periodic table having a group as a ligand.