JP2866434B2 - Method for producing aluminoxane - Google Patents

Description

The present invention relates to a method for producing an aluminoxane, which is suitably used as a catalyst component for producing an olefin-based polymer or a styrene-based polymer. The present invention relates to a method for producing a uniform aluminoxane having excellent storage stability.

[Problems to be solved by conventional technology and invention]

BACKGROUND ART Conventionally, in producing an olefin-based polymer or a styrene-based polymer by polymerizing an olefin or styrene in the presence of a catalyst, a method using a reaction product of a transition metal compound and an aluminoxane as a catalyst has been known ( JP-A-62-36390 and JP-A-59-95292).

By the way, the aluminoxane compound is generally used by dissolving it in an aromatic hydrocarbon solvent such as toluene. When this solution is stored for a long period of time, a viscous gel-like aluminoxane (aluminoxane solid particles) precipitates and is used for storage. There have been problems such as that gel-like particles adhere to the wall surface of the container, or that the concentration of aluminoxane in the solution changes.

In order to solve this problem, a method has been proposed in which an alkyl aluminum is added to the solution (Japanese Patent Laid-Open No. 1-258686).

According to this method, although a homogeneous aluminoxane solution having no gel component can be obtained, the addition of alkyl aluminum changes the polymerization activity of the catalyst, and also has a problem that the physical properties of the resulting polymer are limited. Was.

[Means for solving the problem]

The present inventors have conducted intensive studies to solve such problems, and as a result, when or after the production of an aluminoxane from an organoaluminum compound and water, by presenting a monohydric alcohol in the reaction system. It has been found that an aluminoxane free from such a problem can be produced, and the present invention has been completed based on this finding.

That is, the present invention provides a method for producing an aluminoxane, wherein a monohydric alcohol is present in a reaction system when or after the production of an aluminoxane from an organoaluminum compound and water.

In other words, in the present invention, when producing an aluminoxane from an organoaluminum compound and water, a monohydric alcohol is present (coexisting) in this reaction system, or after producing aluminoxane from an organoaluminum compound and water, And a catalytic reaction by adding a monohydric alcohol thereto.

Although there is no particular limitation on the organic aluminum compound used in the present invention, in the general formula AlR ¹ R ² R ³ [wherein, the R ^1, R ^2, R ³ are each a hydrogen atom or an alkyl group having 1 to 10 carbon atoms And R ¹ , R ² , and R ³ may be the same or different. An alkyl aluminum compound represented by the formula:

Specific examples of such an alkylaluminum compound include trialkylaluminums such as trimethylaluminum, triethylaluminum, and triisobutylaluminum, as well as diethylaluminum hydride and diisobutylaluminum hydride.

Of the above-mentioned organoaluminum compounds, trialkylaluminum is preferred, and trimethylaluminum is particularly preferred.

On the other hand, the water to be reacted with the organoaluminum compound is not limited to ordinary water, ice, and steam, but also various hydrated compounds, for example, solvent-saturated water, water adsorbed by inorganic substances, or copper sulfate pentahydrate (CuSO ₄ .5H ₂ O) contains a metal salt containing crystal water, etc., such as.

In the present invention, when producing an aluminoxane from the above-mentioned organoaluminum compound and water, or after producing an aluminoxane from the above-mentioned organoaluminum compound and water, a monohydric alcohol is present in the reaction system. is there.

Specific examples of the monohydric alcohol used in the present invention include alcohols having a linear alkyl group such as methanol, ethanol, propanol and butanol; alcohols having a branched alkyl group such as isopropanol, isobutanol and tertiary butanol; Alcohols having a phenyl group such as benzhydrol and triphenylmethanol; alcohols having a cyclic alkyl group such as cyclohexanol and cycloheptanol;

In the present invention, as the monohydric alcohol, an alcohol having a branched alkyl group or an alcohol having a bulky group such as triphenylmethanol is preferable because the aluminoxane yield is high.

In the present invention, the above-mentioned organoaluminum compound, water and a monohydric alcohol are brought into contact with each other. Examples of the contacting method include the following three methods i) to iii).

i) A method in which water and an alcohol are dissolved in an organic solvent, and an organic aluminum compound is added thereto.

ii) A method in which an organic aluminum compound and an alcohol are reacted in an organic solvent, and water is added thereto.

iii) A method in which an organic aluminum compound is reacted with water in an organic solvent, and an alcohol is added to the reaction product (ie, aluminoxane).

The methods i) and ii) described above, when producing aluminoxane from the above-mentioned organoaluminum compound and water,
This is included in the method of allowing a monohydric alcohol to be present (coexisting) in the reaction system. On the other hand, the method iii) is to produce aluminoxane from the above-described organoaluminum compound and water, and then to add the monohydric alcohol to the aluminoxane. It is a method of adding and making a contact reaction.

Among them, the method i) is preferable because it also improves the aluminoxane yield.

The above reaction proceeds even without solvent, but is preferably performed in a solvent.

Examples of the organic solvent used herein include aliphatic hydrocarbons and aromatic hydrocarbons. Specifically, aliphatic hydrocarbons such as hexane, heptane, and decane, benzene, toluene, p-xylene, m-xylene, o -Aromatic hydrocarbons such as xylene, ethylbenzene, propylbenzene and cumene.

When the alcohol is added during the reaction between the organoaluminum compound and water (in the methods (i) and (ii)), the amount of the alcohol is 0.00
It is advisable to add 1 to 0.7 times mol, preferably 0.01 to 0.5 times mol.

If the amount of alcohol added is less than 0.001 mole, the effect is difficult to be recognized.On the other hand, if it is used in excess of 0.7 mole, the alkyl group which is important as a catalyst component reacts with the alcohol, so that the alkyl group remains. Since the amount decreases, the effect as a catalyst component tends to decrease.

On the other hand, when the compound is added after the reaction between the organoaluminum compound and water (in the case of the method iii)), the R / Al ratio (amount) is smaller than in the above case, so that On the other hand, 0.0001 to 0.5 times mol, preferably 0.001 to 0.3 times mol is added.

If the amount of alcohol added here is less than 0.0001 mole, the effect is difficult to be recognized.On the other hand, if it is used more than 0.5 mole, the alkyl group which is important as a catalyst component reacts with the alcohol, so that the alkyl group remains. Since the amount decreases, the effect as a catalyst component tends to decrease.

In the case of the above-mentioned methods i) and ii), the reaction conditions are usually the same as those for the preparation of aluminoxane (see, for example,
-36390, JP-A-59-95292, JP-A-64-16
803) etc.).

On the other hand, in the case of the method iii), after preparing an aluminoxane under a general condition, a monohydric alcohol is heated to a temperature of 70 ° C. or less
More specifically, usually 0 ° C to 70 ° C, preferably 20 ° C to 50 ° C
At this temperature, it is preferable to add the alcohol directly or in a liquid state as a dilute solution.

The aluminoxane thus obtained may be used as it is, or after being concentrated or dried.

Here, concentration or drying is performed at 0 to 200 ° C., preferably 1 to 200 ° C.
It may be carried out at a temperature of 0 ° C. to 150 ° C. and under atmospheric pressure or reduced pressure.

Here, when concentration or drying is performed at a temperature exceeding 200 ° C.,
This is not preferable because thermal decomposition of the aluminoxane itself occurs.

By this concentration treatment, highly pure aluminoxane is obtained.

The aluminoxane thus obtained is used in the reaction in a form dissolved in an aromatic hydrocarbon solvent such as toluene.

The aluminoxane obtained as described above may be combined with a transition metal compound to form an olefin polymer such as polyethylene, atactic polypropylene, isotactic polypropylene, polybutene-1, poly4-methylpentene-1 or ethylene. -It can be used as a propylene copolymer or a styrene polymer, more specifically, a styrene polymer having a syndiotactic structure, and further as a catalyst component for low polymerization of propylene.

Here, as the transition metal compound, Periodic Table IV
Any of the transition metals of Groups VIII to VIII may be selected according to the type of the desired polymer. Reaction conditions such as the ratio of the transition metal in the transition metal compound to aluminum in the aluminoxane and the polymerization temperature may be performed under ordinary conditions.

〔Example〕

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

Example 1 (1) Preparation of aluminoxane 100 ml of toluene, 17.7 g of copper sulfate pentahydrate (CuSO ₄ .5H ₂ O) (71 mm) were placed in a 500 ml-volume glass container purged with argon.
ol) and 3.3 ml (36 mmol) of isobutanol.
Cool to ℃, trimethyl aluminum (TMA) 9.6g (133
mmol) was added dropwise. At this time, about 36 mmol of methane gas is generated, and trimethylaluminum and isobutanol are 1: 1.
It turned out that it was reacting.

Thereafter, the mixture was reacted at 40 ° C. for 8 hours to remove solid components, and then toluene was distilled off while stirring the obtained solution at 50 ° C. Once the solution has been removed,
The temperature was raised to 110 ° C., and drying was performed until the distillate disappeared.

As a result, 4.64 g of aluminoxane as a contact product
Obtained.

This was dissolved in 20 ml of toluene and allowed to stand under a dry nitrogen atmosphere for one month, but no gel-like precipitate was formed.

(2) Ethylene polymerization To a nitrogen-purged autoclave having an internal volume of 1, 400 ml of toluene, 1 mmol of the aluminoxane obtained in (1) above as an aluminum atom and 5 μmol of biscyclopentadienyl zirconium dichloride as a transition metal compound were sequentially added. After that, the temperature was raised to 80 ° C.

Next, ethylene was continuously introduced into the autoclave, and a polymerization reaction was carried out at 8 kg / cm ² for 1 hour. After the reaction, methanol was added to decompose the catalyst, followed by drying to obtain 142 g of polyethylene. The polymerization activity of the catalyst is 312 kg / g-Z
r.

(3) Polymerization of styrene In a nitrogen-purged autoclave having an internal volume of 1, 400 ml of styrene, 4 mmol of triisobutylaluminum, 4 mmol of the aluminoxane obtained in the above (1) as an aluminum atom, and pentamethylcyclopentadienyl as a transition metal compound. 20 μmol of titanium trimethoxide was added, and a polymerization reaction was performed at 70 ° C. for 1 hour. After the reaction,
The product was washed with a mixed solution of hydrochloric acid and methanol to separate and remove the catalyst component, and dried to obtain 102.1 g of a polymer. The polymerization activity of the catalyst was 107 kg / g-Ti. The syndiotacticity of this polymer in racemic pentad was 97% by ¹³ C-NMR measurement.

 Table 1 shows the results.

Comparative Example 1 (1) Preparation of aluminoxane Aluminoxane was synthesized in the same manner as in Example 1 (1) except that isobutanol was not used, and 3.9 g of a solid component was obtained. Obtained.

This was dissolved in 20 ml of toluene and allowed to stand for one month in a dry nitrogen atmosphere, whereby a gel-like precipitate was formed.

(2) Polymerization of ethylene In Example 1 (2), except that the aluminoxane obtained in the above (1) was used as the aluminoxane,
Polymerization of ethylene was carried out in the same manner as in Example 1 (2),
130 g of polyethylene were obtained. The polymerization activity of the catalyst is 286 kg / g-Z
r.

(3) Polymerization of styrene In Example 1 (3), except that the aluminoxane obtained in the above (1) was used as the aluminoxane,
Polymerization of ethylene was carried out in the same manner as in Example 1 (3),
91.4 g of syndiotactic polystyrene was obtained. The polymerization activity of the catalyst was 95 kg / g-Ti.

 Table 1 shows the results.

Example 2 (1) Preparation of methylaluminoxane Aluminoxane was produced in the same manner as in Example 1 (1) except that tert-butanol was used instead of isobutanol in Example 1 (1). 4.3 g of a solid component (methylaluminoxane) was obtained.

This was dissolved in 20 ml of toluene and left under a dry nitrogen atmosphere for one month, but no gel-like precipitate was formed.

(2) Polymerization of ethylene In Example 1 (2), except that the aluminoxane obtained in the above (1) was used as the aluminoxane,
Polymerization of ethylene was carried out in the same manner as in Example 1 (2).
The polymerization activity of the catalyst was 321 kg / g-Zr.

(3) Polymerization of styrene In Example 1 (3), except that the aluminoxane obtained in the above (1) was used as the aluminoxane,
Polymerization of styrene was carried out in the same manner as in Example 1 (3). The polymerization activity of the catalyst was 108 kg / g-Ti.

 Table 1 shows the results.

Examples 3 to 8 Various aluminoxanes were obtained in the same manner as in Example 1 (1), except that the type and amount of the alcohol used were changed to the conditions shown in Table 1 in Example 1 (1). .

These were dissolved in 20 ml of toluene and left for one month in a dry nitrogen atmosphere, but no gel-like precipitate was formed in any case.

Hereinafter, polymerization of ethylene and styrene was performed in the same manner as in Example 1 (2) and Example 1 (3) except that this aluminoxane was used.

 Table 1 shows the results.

Example 9 (1) Preparation of aluminoxane 30 mmol of methylaluminoxane obtained in Comparative Example 1 (1) was used as an aluminum atom, and 0.6 ml (6.5 mmol) of isobutanol was added thereto at room temperature to obtain a homogeneous solution. .

This was left under a dry nitrogen atmosphere for one month, but no gel-like precipitate was formed.

(2) Polymerization of ethylene In Example 1 (2), except that the aluminoxane obtained in the above (1) was used as the aluminoxane,
Polymerization of ethylene was carried out in the same manner as in Example 1 (2). The polymerization activity of the catalyst was 311 kg / g-Zr.

(3) Polymerization of styrene In Example 1 (3), except that the aluminoxane obtained in the above (1) was used as the aluminoxane,
Polymerization of styrene was carried out in the same manner as in Example 1 (3). The polymerization activity of the catalyst was 106 kg / g-Ti.

〔The invention's effect〕

According to the method of the present invention, a gel-free homogeneous aluminoxane solution can be obtained.

Therefore, the storage stability is extremely excellent without adding alkyl aluminum or the like as in the prior art, and there is no adverse effect due to the addition of alkyl aluminum.

According to the method of the present invention, the aluminoxane yield is excellent, and the obtained aluminoxane has high catalytic activity.

Therefore, the present invention can be effectively used for producing a catalyst component for producing an olefin polymer or a styrene polymer.

Claims (1)

(57) [Claims] 1. A method for producing an aluminoxane, wherein a monohydric alcohol is present in a reaction system during or after producing an aluminoxane from an organoaluminum compound and water.