JPH0441164B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing polyolefins, and more specifically, a method for producing polyolefins such as polyethylene and polypropylene, particularly polyethylene and high molecular weight atactic polypropylene, using a catalyst having a specific component composition. Regarding the method.

Conventionally, the manufacturing method of polyolefin is as follows:
A method using a so-called Ziegler catalyst is widely known, but a method using a polymerization catalyst consisting of a cyclopentadienyl compound such as titanium or zirconium and aluminoxane has also been proposed (U.S. Pat. No. 3,242,099, JP Showa 58-19309
Publication No.). In particular, JP-A-58-19309 discloses a method of polymerizing olefin using bis(cyclopentadienyl)zirconium dichloride and aluminoxane obtained by reacting trialkylaluminium with water as a catalyst. .

However, this method has the disadvantage that the molecular weight of the obtained polyolefin, especially atactic polypropylene, is small, and the aluminoxane used here has poor production stability and poor performance because the reaction between trialkylaluminum and water is extremely violent. The problem was that the stability was not sufficient. Furthermore, when propylene is polymerized using this, there is a drawback that polypropylene having a sufficiently large molecular weight cannot be obtained.

Therefore, the inventors of the present invention have conducted various studies in order to solve the problems in the conventional technology, and as a result,
By using aluminoxane obtained by the reaction of a titanium compound having a cyclopentadienyl group and a specific dialkyl aluminum compound with water as a catalyst, high molecular weight atactic polypropylene can be efficiently obtained, and extremely high It has been discovered that polyethylene can be produced with catalytic activity. The present invention was completed based on this knowledge.

That is, the present invention provides (A) a transition metal compound and (B)
When producing polyolefin by polymerizing olefin using a catalyst containing an organoaluminum compound as the main component, (A) transition metal compound has the general formula (cp) TiR ¹ R ² R ³ (where cp is cyclopentadiene). It represents an enyl group, and R ¹ , R ² , and R ³ each have 1 to 1 carbon atoms.
6 alkyl group, cyclopentadienyl group, hydrogen atom or halogen atom). In addition to using a titanium compound represented by (B) an organoaluminum compound, a dialkyl represented by the general formula R ⁴ ₂ A1X (wherein R ⁴ represents a methyl group or an ethyl group, and X represents a halogen atom). The present invention provides a method for producing polyolefin, which is characterized by using aluminoxane obtained by a reaction between an aluminum compound and water.

The catalyst used in the method of the present invention has the above-mentioned components (A) and (B) as main components. As the transition metal compound which is the component (A) of this catalyst, compounds represented by the general formula (cp) TiR ¹ R ² R ³ are used as described above, but among them, bis(cyclopentadienyl) titanium Preferred are dichloride, cyclopentadienyl titanium trichloride, bis(cyclopentadienyl) titanium methyl chloride, and the like.

Further, as the organoaluminum compound which is the component (B) of this catalyst, an aluminoxane obtained by the reaction of a dialkylaluminum compound represented by the general formula R ⁴ ₂ A1X with water is used as described above. Examples of the dialkyl aluminum compound include dimethylaluminum monochloride, diethylaluminum monochloride, diethylaluminium monobromide, diethylaluminium monoiodide, diisopropylaluminum monochloride, diisobutylaluminum monochloride, and the like. In addition, this aluminoxane can be prepared under various conditions, but
Usually, a dialkylaluminum compound is added to an organic solvent such as benzene, toluene, or xylene and mixed, and then copper sulfate pentahydrate (CuSO ₄ .5H ₂
By adding a salt having water of crystallization such as O) or water and reacting at room temperature to heating, the desired aluminoxane can be obtained.

In the method of the present invention, an olefin is polymerized using both components (A) and (B) of the above-mentioned transition metal compound and (B) organoaluminum compound as catalysts to produce a polyolefin.

In the polymerization of olefin, the above-mentioned catalyst components are added to the reaction system, and then the olefin as a raw material is introduced into the system. The polymerization method and conditions are not particularly limited, and any of solution polymerization, suspension polymerization, gas phase polymerization, etc. is possible, and both continuous polymerization and discontinuous polymerization are possible. For example, in the case of solution polymerization or suspension polymerization, the amount of the catalyst component added is 0.0001 to 0.5 when converting component (A) into titanium atoms.
mmol/, preferably 0.001 to 0.1 mmol/
and component (B) is 1 to 100,000, preferably aluminum atoms/titanium atoms, relative to component (A).
100 to 10000. The olefin pressure in the reaction system is preferably normal pressure to 50 kg/cm ² G, and the reaction temperature is 0.
-200°C, preferably 20-150°C. Molecular weight adjustment during polymerization can be carried out by known means, such as hydrogen. The reaction time varies depending on the type of olefin used as the raw material, but is selected within the range of 1 minute to 2 hours for ethylene and 30 minutes to 100 hours for propylene.

There are various types of olefins that can be polymerized by the method of the present invention, including linear monoolefins such as ethylene, propylene, butene-1, hexene-1, and octene-1, as well as 4-methyl-pentene-1 and the like. branched monoolefins, dienes such as butadiene, and others, and the present invention
It can be effectively used for homopolymerization of these or copolymerization of various olefins.

According to the method of the present invention, the catalyst used is easy to prepare, the amount of transition metal compound consumed during this preparation is small, and almost all of the transition metal compound used is used as a catalyst, so it is discarded. No equipment required for processing. Moreover, since the catalytic activity is extremely high, particularly the polymerization activity for ethylene is extremely high, a deashing step (catalyst removal step) is not necessary, and as a result, polyolefin can be produced extremely efficiently. In addition, this polyolefin, especially when propylene is used as the raw material olefin, becomes a high molecular weight atactic polypropylene, which can be effectively used for various purposes.

Next, the present invention will be explained in more detail with reference to Examples.

Example 1 (1) Preparation of aluminoxane 195 mmol of dimethylaluminum monochloride was added to 100 ml of toluene, and copper sulfate pentahydrate ( _CuSO4 .
56.2 mmol of 5H ₂ O) was added, and the mixture was reacted at 20° C. for 24 hours. During this time, approximately 0.2 moles of methane were generated. Next, copper sulfate was filtered off from the resulting reaction solution, and toluene was distilled off to obtain 11.8 g of chloraluminoxane. The molecular weight of the chloraluminoxane obtained here was 730 as measured by the benzene freezing point depression method.

(2) Polymerization of ethylene In an autoclave with an internal volume of 1, add 400 g of toluene.
ml and chloraluminoxane obtained in (1) above 8.0
Add mmol and 0.002 mmol of bis(cyclopentadienyl)titanium dichloride at 50°C.
The temperature rose to . Next, ethylene was continuously introduced into the autoclave, the total pressure was maintained at 8 kg/cm ² G, and a polymerization reaction was carried out for 1 hour. After the reaction was completed, methanol was added to stop the polymerization, and the mixture was dried to obtain 38.5 g of polyethylene. The polymerization activity of this catalyst was 402 Kg/g·Ti·hr.

Example 2 Example 1 except that the amount of chloraluminoxane used in Example 1 (2) was 4.0 mmol.
20.8 g of polyethylene was obtained in the same manner as in (2). The polymerization activity of the catalyst was 217 Kg/g·Ti·hr.

Example 3 The amount of chloraluminoxane used in Example 1 (2) was set to 2.0 mmol, and the amount of bis(cyclopentadienyl) titanium dichloride used was set to 2.0 mmol.
22.5 g of polyethylene was obtained in the same manner as in Example 1 (2) except that the amount was 0.004 mmol. The polymerization activity of the catalyst was 117 Kg/g·Ti·hr.

Example 4 27.0 g of polyethylene was obtained in the same manner as in Example 1 (2) except that 400 ml of hexane was used in place of toluene as the polymerization solvent in Example 1 (2).
The polymerization activity of the catalyst was 282 Kg/g·Ti·hr.

Example 5 Example 1 except that the amount of chloraluminoxane used in Example 1 (2) was 5.0 mmol, and 0.005 mmol of cyclopentadienyl titanium trichloride was used as the transition metal compound.
6.2 g of polyethylene was obtained in the same manner as in (2). The polymerization activity of the catalyst was 26 Kg/g·Ti·hr.

Comparative Example 1 Example 2 except that 0.002 mmol of bis(cyclopentadienyl)zirconium dichloride was used as the transition metal compound in Example 2.
0.1 g of polyethylene was obtained in the same manner as above. The polymerization activity of the catalyst was 0.5 Kg/g.Zr.hr.

Example 6 Toluene 200 was added to an autoclave with an internal volume of 1.
ml, chloraluminoxane obtained in Example 1
4.0 mmol and bis(cyclopentadienyl)
0.002 mmol of titanium dichloride was added.
Next, propylene was continuously introduced into the autoclave, and the polymerization reaction was carried out for 7 hours at 20° C. while maintaining the total pressure at 8 kg/cm ² G. As a result, 9.6 g of polypropylene was obtained. The polymerization activity of the catalyst is 100
Kg/g·Ti, and the molecular weight of this polypropylene was 64,000. Note that the polypropylene obtained here was 100% atactic polypropylene.

Example 7 5.2 g of atactic polypropylene was obtained in the same manner as in Example 6 except that the amount of chloraluminoxane used in Example 6 was changed to 1.2 mmol. The polymerization activity of the catalyst was 54 Kg/g·Ti, and the molecular weight of the obtained polypropylene was 123,000.

Example 8 12.5 g of atactic polypropylene was obtained in the same manner as in Example 6, except that the polymerization temperature in Example 6 was 50°C. The polymerization activity of the catalyst is 130Kg/
g.Ti, and the molecular weight of the obtained polypropylene was 21,000.

Comparative Example 2 Example 6 except that 0.002 mmol of bis(cyclopentadienyl)zirconium dichloride was used as the transition metal compound in Example 6.
The reaction was carried out in the same manner as above, but polypropylene was not obtained.

Example 9 In Example 1 (2), as the transition metal compound,
Example 1(2) except that bis(cyclopentadienyl) titanium chloride hydride was used.
In the same manner as above, 37.0 g of polyethylene was obtained. The polymerization activity of the catalyst was 386 Kg/g·Ti·hr.

Example 10 In Example 1 (2), as the transition metal compound,
40.0 g of polyethylene was obtained in the same manner as in Example 1(2) except that bis(cyclopentadienyl)titanium dimethyl was used. The polymerization activity of the catalyst is 418
It was Kg/g・Ti・hr.

Example 11 In Example 1 (2), as the transition metal compound,
39.0 g of polyethylene was obtained in the same manner as in Example 1 (2) except that bis(cyclopentadienyl) titanium methyl chloride was used. The polymerization activity of the catalyst was 407 Kg/g·Ti·hr.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the steps for preparing a catalyst used in the method of the present invention.

Claims (1)

[Claims] 1. In producing polyolefin by polymerizing olefin using a catalyst mainly composed of (A) a transition metal compound and (B) an organoaluminium compound, (A)
General formula (cp) TiR ¹ R ² R ³ as a transition metal compound
(In the formula, cp represents a cyclopentadienyl group,
R ¹ , R ² and R ³ each represent an alkyl group having 1 to 6 carbon atoms, a cyclopentadienyl group, a hydrogen atom or a halogen atom. ), and (B) an organoaluminum compound represented by the general formula R ⁴ ₂ A1X (wherein R ⁴ represents a methyl group or an ethyl group, and X represents a halogen atom). 1. A method for producing a polyolefin, comprising using aluminoxane obtained by a reaction between a dialkylaluminum compound and water.