JPS646204B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to a process for polymerizing ethylene in the presence of a novel catalyst.

Many proposals have been made regarding the method of polymerizing ethylene in the presence of a catalyst obtained from a solid catalyst component in which a titanium compound or a vanadium compound is supported on a magnesium compound and an organoaluminium compound. Catalysts that use a solid catalyst component in which a vanadium compound is supported on a magnesium compound currently have lower ethylene polymerization activity than catalysts that use a solid catalyst component in which a titanium compound is supported on a magnesium compound. . Therefore,
Polyethylene obtained with a catalyst using a solid catalyst component in which a vanadium compound is supported on a magnesium compound requires an operation to remove the catalyst residue.

The present invention provides an ethylene polymerization method that provides a high polymer yield per solid catalyst component containing a vanadium compound.

That is, the present invention provides a reaction product between an aluminum halide and an organosilicon compound represented by the formula Si(OR ¹ ) ₄ [] (wherein R ¹ represents an alkyl group having 1 to 8 carbon atoms). A Grignard compound represented by the formula R ² MgX ¹ [] (wherein R ² represents an alkyl group having 1 to 8 carbon atoms and X ¹ represents a halogen atom) is reacted with the resulting solid and oxy A solid catalyst component obtained by contacting vanadium trihalide with the formula R ³ ₂ AlX ² [] (wherein, R ³ represents an alkyl group having 2 to 6 carbon atoms, and X ² represents a halogen atom. ) is a method for polymerizing ethylene, which is characterized by polymerizing ethylene in the presence of a catalyst obtained from an organoaluminum compound represented by:

According to this invention, since the polymer yield per solid catalyst component is large, it is possible to omit the operation of removing catalyst residue from the produced polymer.

FIG. 1 shows the ethylene polymerization method of the present invention and the preparation process of the solid catalyst component used in the polymerization.

In this invention, the solid catalyst component is prepared using substantially anhydrous compounds under an inert gas atmosphere such as nitrogen, argon, etc.

Specific examples of the aluminum halide in this invention include aluminum chloride, aluminum bromide, and aluminum iodide, among which aluminum chloride is preferably used.

Specific examples of the organosilicon compound represented by the formula [] include tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, tetrabutoxysilane, and tetrapentoxysilane.

The proportion of aluminum halide used in the reaction is preferably 0.25 to 10 mol, particularly about 1 mol, per mol of organosilicon compound.

The reaction between aluminum halide and organosilicon compound is usually carried out by stirring both compounds in an inert organic solvent at a temperature in the range of -50 to 100°C for 0.1 to 2 hours. The reaction proceeds with exotherm, and the reaction product is obtained as a solution in an inert organic solvent. The reaction product can be subjected to the reaction with the Grignard compound as the above solution without being isolated.

Among the Grignard compounds represented by the formula [], alkylmagnesium chlorides in which X ¹ is a chlorine atom are preferably used, and specific examples thereof include methylmagnesium chloride, ethylmagnesium chloride, butylmagnesium chloride, hexylmagnesium chloride, etc. It will be done.

The amount of Grignard compound used per mole of organosilicon compound used for the preparation of the reaction product is:
Preferably it is between 0.05 and 4 mol, especially about 2 mol.

There is no particular restriction on the method of reacting the reaction product with the Grignard compound, but an ether solution of the Grignard compound or a mixed solvent solution of ether and an aromatic hydrocarbon is gradually added to the solution of the reaction product in an inert organic solvent. Conveniently this is done by addition or addition in the reverse order. The above ether is
It is preferable to use a compound represented by the formula R ⁴ -0-R ⁵ (wherein R ⁴ and R ⁵ each represent an alkyl group having 2 to 8 carbon atoms).

The reaction temperature is usually -50 to 100℃, preferably -20℃
~25℃. There is no particular restriction on the reaction time, but it is usually 5 minutes or more. As the reaction progresses, a white solid precipitates out. The solid thus obtained can be contacted as a reaction product mixture with vanadium oxytrihalide, but it is preferably washed with an inert organic solvent before contacting with vanadium oxytrihalide.

Specific examples of vanadium oxytrihalide include vanadium oxytrichloride and vanadium oxytribromide, of which vanadium oxytrichloride is preferably used.

The amount of vanadium oxytrihalide used is preferably 0.05 mol or more, particularly 0.1 to 10 mol, per 1 mol of the Grignard compound used in the preparation of the solid.

The solid and vanadium oxytrihalide are usually combined in the presence or absence of an inert organic solvent.
Contacting is preferably carried out at a temperature in the range 20-200°C, preferably 60-140°C. There are no particular restrictions on the contact time, but it is usually 0.5 to 3 hours.

The solid catalyst component is separated from the thus obtained mixture containing the solid catalyst component by filtration, decanting, etc., and washed with an inert organic solvent. The solid catalyst component contains 0.5 to 10% by weight of vanadium.

Inert organic solvents used in each step of preparing the solid catalyst component include aliphatic hydrocarbons such as hexane and heptane, alicyclic hydrocarbons such as cyclohexane and cyclopentane, and aromatic hydrocarbons such as benzene, toluene and xylene. Examples include hydrogen and halides of these hydrocarbons.

In this invention, the solid catalyst component and the formula []
Ethylene is polymerized in the presence of a catalyst obtained from an organoaluminum compound represented by:

Among the organoaluminum compounds represented by the formula [], dialkylaluminum chloride in which X ² is a chlorine atom is preferably used, and specific examples thereof include diethylaluminum chloride, dibutylaluminum chloride, dihexylaluminum chloride, and the like.

The amount of organoaluminum compound used is usually 1 gram atom of vanadium in the solid catalyst component.
~1000 mol.

The polymerization reaction of ethylene can be carried out in a liquid phase or a gas phase.

When carrying out a polymerization reaction in a liquid phase, for example, aliphatic hydrocarbons such as hexane and heptane, alicyclic hydrocarbons such as cyclohexane and cyclopentane, and aromatic hydrocarbons such as benzene and toluene are used as the polymerization solvent. Ru. There are no particular restrictions on the catalyst concentration in the polymerization solvent, but in general, the solid catalyst component is 0.001 to 10 milligram atoms per polymerization solvent in terms of vanadium metal, and the organoaluminum compound is 0.001 to 1000 per polymerization solvent. Millimoles.

In this invention, not only ethylene is polymerized alone, but also ethylene and α-
Olefins such as propylene, 1-butene, 4-methyl-1-pentene, 1-hexene, etc. can be copolymerized.

In this invention, the polymerization reaction is carried out in a state substantially free of moisture and oxygen, similar to the usual polymerization reaction of ethylene using a Ziegler type catalyst.

The polymerization temperature is usually 30 to 100°C, and the polymerization pressure is usually 1 to 80 kg/cm ² .

In this invention, the molecular weight of the ethylene polymer obtained can be easily adjusted by adding hydrogen or a halogenated hydrocarbon, such as chloroform or 1,2-dichloroethane, to the polymerization system.

Next, examples will be shown. In the following description,
"Polymerization activity" is the polymer yield (g) per 1 hour of polymerization time per 1 g of solid catalyst component used in the polymerization reaction. In the Examples, all solid catalyst components were prepared in a dry nitrogen gas atmosphere.

Example 1 (1) Preparation of solid catalyst component: 15 mmol of anhydrous aluminum chloride was mixed with 40 mmol of toluene.
ml, then 15 mmol of tetraethoxysilane was added, and the reaction was allowed to proceed at 25° C. for 1 hour with stirring.

After the reaction product mixture was cooled to -10° C., 25 ml of diisoamyl ether containing 30 mmol of n-butylmagnesium chloride was added dropwise to the reaction product mixture over 60 minutes while stirring. The temperature of the reaction system is -10 to 0
It was kept within the range of ℃. After the dropwise addition was completed, the reaction was continued for 1 hour at -10°C. The precipitated solid was separated and washed with toluene and then n-heptane. The results of elemental analysis of this solid are shown below.

Mg: 14.5% by weight, Al: 1.5% by weight, Si: 4.7% by weight, Cl: 43.8% by weight, -OC ₂ H ₅ : 20.1% by weight. 1 g of this solid was suspended in 40 ml of n-hexane,
4 mmol of vanadium oxytrichloride was added to this suspension, and the solid was brought into contact with the vanadium oxytrichloride for 2 hours at 70° C. with stirring. After washing the obtained solid catalyst component with n-hexane, it was washed with n-hexane under reduced pressure.
Hexane was distilled off to obtain a powdery solid catalyst component. The vanadium content of the solid catalyst component was 1.7% by weight.

(2) Polymerization: A glass ampoule containing 5.6 mg of the solid catalyst component was placed in an autoclave with an internal volume of 1 and equipped with a stirrer, and then the air in the autoclave was replaced with nitrogen.

250 ml of n-hexane containing 1.0 mmol of diethylaluminium chloride was introduced into the autoclave, and the autoclave contents were heated to 70°C.
Then, ethylene was introduced until the pressure reached 15 kg/cm ² (gauge pressure), stirring of the autoclave was started, the glass ampoule was crushed, and ethylene was polymerized at 70° C. for 1 hour. During the polymerization, ethylene was continuously supplied to maintain the ethylene pressure at 15 Kg/cm ² (gauge pressure).

After the polymerization reaction was completed, unreacted ethylene was released, the polymer was separated, and then dried under reduced pressure at 60° C. for 10 hours to obtain 95.2 g of white powdery polyethylene.

The density of the produced polyethylene was 0.924 g/cm ² and the polymerization activity was 17,000.

Example 2 The amount of diethyl aluminum chloride used
Example 1 was repeated except that the amount was changed to 0.58 mmol. The polymerization activity was 17,300.

Example 3 The amount of diethyl aluminum chloride used
Example 1 was repeated except that the amount was changed to 0.22 mmol. The polymerization activity was 10,100.

Example 4 Example 2 was repeated except that 0.45 mmol of 1,2-dichloroethane was introduced into the autoclave prior to the introduction of ethylene. The polymerization activity was 9350.

[Brief explanation of drawings]

FIG. 1 is a flowchart showing the ethylene polymerization method of the present invention.

Claims (1)

[Scope of Claims] 1. A reaction product between aluminum halide and an organosilicon compound represented by the formula Si(OR ¹ ) ₄ (wherein R ¹ represents an alkyl group having 1 to 8 carbon atoms), A Grignard compound represented by the formula R ² MgX ¹ (wherein R ² represents an alkyl group having 1 to 8 carbon atoms, and X ¹ represents a halogen atom) is reacted with the resulting solid and vanadium oxytrihalide. and an organoaluminum represented by the formula R ³ ₂ AlX ² (wherein, R ³ represents an alkyl group having 2 to 6 carbon atoms, and X ² represents a halogen atom). A method for polymerizing ethylene, which comprises polymerizing ethylene in the presence of a catalyst obtained from a compound.