JP2708586B2 - Method for producing syndiotactic poly-α-olefin - Google Patents

Description

The present invention relates to a method for producing a syndiotactic poly-α-olefin using a novel highly active polymerization catalyst. Specifically, the present invention relates to a method for producing a syndiotactic poly-α-olefin in the presence of a catalyst comprising a specific transition metal compound and an aluminoxane.

[Conventional technology]

Syndiotactic poly-α-olefins, especially syndiotactic polypropylene, have long been known to be obtainable by a low-temperature polymerization method using a catalyst composed of a vanadium compound and an organoaluminum. Had poor syndioctacycity and could not be said to represent the characteristics of a true syndiotactic poly-α-olefin.

On the other hand, JAEWEN et al. Reported that a catalyst comprising a transition metal compound having an isopropylidene (cyclopentadienyl-fluorenyl) group as a ligand and an aluminoxane had good tacticity such that the syndiotactic pentad fraction exceeded 0.8. For the first time was obtained (J. Am. Chem. Soc., 1988, 110, 62).
55-6256).

A catalyst comprising an aluminoxane and a transition metal compound having a fluorenyl group as a ligand similar to JAEWEN et al.
64-66214, but there is no description of a transition metal compound in which a compound in which a cyclopentadienyl group and a fluorenyl group are bonded as a ligand as in the present invention is used. JP 64
As disclosed in -66214, even when an α-olefin is polymerized using a transition metal compound in which a fluorenyl group is bonded to a transition metal and an aluminoxane as a catalyst, the syndiotactic poly- formed by the catalyst system of the present invention is used. α-olefins are not available and are a completely different catalyst system.

[Problems to be solved by the invention]

The above-mentioned method by JAEWEN et al. Has a good activity per transition metal, and is an excellent method in which the obtained polymer has a high syndioctacycity, but the catalyst is unstable and the transition metal catalyst and aluminomisan are mixed. However, there was a problem that the activity decreased with time.

[Means for solving the problem]

Means for Solving the Problems The inventors of the present invention have solved the above-mentioned problems and have intensively studied a method for producing poly-α-olefin having high activity and high syndioctacy with good productivity, and have completed the present invention.

That is, the present invention provides a method of polymerizing an α-olefin using a catalyst comprising (A) a transition metal compound and (B) an aluminoxane, wherein (A) cycloalkylidene (cyclopentadienyl-1-fluorenyl) is used as the transition metal compound. ) A method for producing a syndiotactic poly-α-olefin, characterized by using a transition metal compound of Group IVB of the Periodic Table having a group as a ligand.

The transition metal compound of Group IVB of the Periodic Table IV having a cycloalkylidene (cyclopentadienyl-1-fluorenyl) group as a ligand used in the present invention is represented by a general formula: (Where A ¹ represents a cyclopentadienyl group, A ² represents a fluorenyl group, A ³ represents a cycloalkylidene group having 4 to 10 carbon atoms, and R ¹ and R ² represent an aryl group, an alkyl group A cycloalkyl group, a halogen atom, a hydrogen atom, or a silyl group, and M is titanium, zirconium, or haunium.

Specific examples of the transition metal compound include, for example, cyclohexylidene (cyclopentadienylfluorenyl) titanium dimethyl, cyclohexylidene (cyclopentadienyl-fluorenyl) zirconium dimethyl, cyclohexylidene (cyclopentadienyl-fluorenyl) ) Hafnium dimethyl, cyclosiliden (cyclopentadienyl-fluorenyl) titanium diphenyl, cyclohexylidene (cyclopentadienyl-fluorenyl) zirconium diphenyl, cyclohexylidene (cyclopentadienyl-fluorenyl) hafnium diphenyl, cyclohexylidene (cyclopentane) Dienyl-fluorenyl) titanium dichloride, cyclohexylidene (cyclopentadienyl-fluorenyl) zirconium dichloride, cyclo Xylidene (cyclopentadienyl-fluorenyl) hafnium dichloride, cyclobutenylidene (cyclopentadienyl-fluorenyl) zirconium dichloride, cyclopentenylidene (cyclopentadienyl-fluorenyl) hafnium dichloride, cyclodecanilidene (cyclopentadiene) (Enyl-fluorenyl) zirconium dichloride and the like.

The aluminoxane as the component (B) in the catalyst used in the present invention has a general formula Wherein R is a hydrocarbon group having 1 to 3 carbon atoms, and n is an integer of 2 or more. In particular, R is a methylaluminoxane wherein R is a methyl group, and n is 5 or more, preferably n is 10 or more. The above are used.

A method for producing the above-mentioned aluminoxane is known. For example, a method for producing aluminoxane by converting a trialkylaluminum into a salt containing water of crystallization (eg, copper sulfate hydrate, magnesium chloride hydrate) in a hydrocarbon solvent and reacting the salt. Or a method of directly reacting a trialkylaluminum with water in an organic compound solvent.

The catalyst component (A) and / or (B) may be used as it is or by being supported on a known carrier that supports a Ziegler-type catalyst.

The use ratio of the aluminoxane to the transition metal catalyst is 10 to 10,000 mol times, usually 50 to 5000 mol times. In the present invention, specific examples of the α-olefin supplied at the time of polymerization include propylene, 1-butene, and 1-butene.
Hexene, 4-methyl-1-pentene, 1-octene,
Α having 3 to 25 carbon atoms such as 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, and 1-octadecene
-Olefins.

In the present invention, a copolymer of ethylene or α-olefin having about 2 to 25 carbon atoms such as propylene and ethylene, propylene and 1-butene is used as long as it exhibits not only α-olefin homopolymerization but also a syndiotactic structure. It can also be used when manufacturing.

Examples of the hydrocarbon medium used in the polymerization or copolymerization include, for example, aromatic hydrocarbons such as butane, pentane, hexane, heptane, octane, nonane, decane, cyclopentane, and cyclohexane as well as aromatic hydrocarbons such as benzene, toluene, and xylene. Hydrocarbons and α-olefins as raw materials can also be used.

The polymerization conditions are not particularly limited, and a solvent polymerization method (suspension polymerization, solution polymerization) using an inert hydrocarbon medium,
Alternatively, a bulk polymerization method and a gas phase polymerization method, which are numbered under the condition that substantially no inert hydrocarbon medium is present, can also be used.

In general, the polymerization is carried out at a temperature of -100 to 200 ° C. and at a pressure of normal pressure to 100 kg / cm ² . Preferably -5
0 to 100 ° C, normal pressure to 50 kg / cm ² .

〔Example〕

 Hereinafter, the method of the present invention will be described by way of examples.

Example 1 Synthesis of transition metal compound [Preparation of cyclohexylidene (cyclopentadiene-1-fluorene)] 11.4 g (63.4 mmol) of fluorene was placed in tetrahydrofuran 150 in a 300 ml glass flask which was sufficiently purged with nitrogen.
Dissolved in ml. To this solution, 70 mmol of an ether solution of methyllithium was added dropwise at -78 ° C. After completion of the dropwise addition, the reaction solution was raised to room temperature, and stirred at that temperature for 3 hours. To this reaction solution, 10 g of 6,6-pentamethylenefulvene diluted with 50 ml of tetrahydrofuran (J. Org. Chem., 198
4,49,1849-1853) was added dropwise.
After completion of the dropwise addition, the reaction temperature was raised to room temperature, and stirring was continued for another 10 hours. The reaction was stopped by charging 200 ml of 3.6% aqueous hydrochloric acid, and the ether layer was washed with water and evaporated to dryness to obtain a yellow-white solid. This solid is acetone 10
By washing with 0 ml, 12.4 g of white cyclohexylidene (cyclopentadiene-1-fluorene) was obtained.

[Preparation of cyclohexylidene (cyclopentadienyl-1-fluorenyl) zirconium dichloride] The cyclohexylidene (cyclopentadiene-1-fluorene) prepared above is lithium-lithiated with n-butyllithium to give cyclohexylidene (cyclo). A dilithium salt of (pentadiene-1-fluorene) was produced.
5.5 g of zirconium tetrachloride was suspended in 100 ml of methylene chloride in a 500 ml glass flask sufficiently purged with nitrogen. 300 ml of a methylene chloride solution of cyclohexylidene (cyclopentadienyl-1-fluorenyl) dilithium dissolved at -78 ° C was introduced into the suspension at -78 ° C. After stirring at −78 ° C. for 4 hours, the temperature is raised to room temperature, and
The reaction was performed for 15 hours. The red-brown solution containing a white precipitate of lithium chloride was filtered off, and the red-brown filtrate was concentrated and cooled at −30 ° C. for 24 hours to obtain cyclohexylidene (cyclopentadienyl-1-fluorenyl) zirconium dichloride as red crystals. 2.3 g were obtained.

(Preparation of catalyst mixture)

After the 100 ml glass flask was replaced with nitrogen, 10 mg of cyclohexylidene (cyclopentadienyl-1-fluorenyl) zirconium dichloride synthesized in Example 1 was dissolved in 10 ml of toluene.

To this solution, 1.2 g of methylaluminoxane manufactured by Tosoh Akzo Co., Ltd. was added to prepare a purple catalyst solution.

(Polymerization method)

After the autoclave of No. 2 was replaced with nitrogen, toluene 1
The catalyst solution prepared in Example 2 was charged and converted to 2r atoms.
0.0046 mmol was added. Add 3 kg /
Polymerization was carried out at 20 ° C. for 2 hours while maintaining cm ² . After the polymerization, the slurry was taken out and dried by filtration to obtain 98.5 g of syndioctatic polypropylene. Even when the filtrate was distilled off under reduced pressure to remove the solvent, 0.1 g of the component was soluble in toluene. The intrinsic viscosity (hereinafter abbreviated as η) of the powder measured with a tetralin solution at 135 ° C. is 1.45 dl / g, and the syndiotactic pentad fraction measured from the area fraction of the peak at 20.24 ppm by ¹³ C-NMR is 0.90. Met.

When the above-mentioned catalyst mixed solution was stored at room temperature for 24 hours and polymerized in the same manner, the obtained polymer was 95.3 g of toluene-insoluble matter and 0.1 g of toluene-soluble matter, and was polymerized immediately after preparing the catalyst mixed solution. It was not different from the result.

Comparative Example 1 [Preparation of Catalyst] Isopropylidene (cyclopentadienyl-1-fluorenyl) zirconium obtained by lithiating isopropylidene (cyclopentadiene-1-fluorene) synthesized according to a conventional method and reacting it with zirconium tetrachloride. 10 mg of dichloride was dissolved in 10 ml of toluene. A purple catalyst solution was prepared by adding 1.3 g of methylaluminoxane to this solution.

[Polymerization method] Polymerization was carried out in the same manner as in [Polymerization method] of Example 1, 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.
The η of the powder was 1.38 dl / g, and the pentad fraction of the syndiotactic was 0.91.

However, as in Example 1, the catalyst mixture was stored at room temperature for 24 hours and then used. The polymer obtained was 15.0 g of toluene-insoluble matter and 0.4 g of toluene-soluble matter. Thus, it is extremely unstable as compared with the catalyst of Example 1.

〔The invention's effect〕

By carrying out the method of the present invention, a syndiotactic poly-α-olefin can be produced with stable performance, which is extremely valuable industrially.

 ──────────────────────────────────────────────────続 き Continuing from the front page Examiner Hitoshi Kobayashi (56) References JP-A-2-173111 (JP, A)

Claims (1)

(57) [Claims] 1. A method for polymerizing an α-olefin using a catalyst comprising (A) a transition metal compound and (B) an aluminoxane, wherein (A) cycloalkylidene (cyclopentadienyl-1-fluorenyl) is used as the transition metal compound. A method for producing a syndiotactic poly-α-olefin, which comprises using a transition metal compound of Group IVB of the Periodic Table having a group as a ligand.