JPH01129003A - Production of poly-alpha-olefin - Google Patents

Abstract

PURPOSE:To obtain a polyolefin containing a large proportion of an isotactic structure, by polymerizing an alpha-olefin by using a titanium compound, a zirconium compound and an aluminoxane. CONSTITUTION:A process for producing a poly-alpha-olefin by polymerizing an alpha-olefin by using a transition metal compound (A) and an organometallic compound (B), wherein said transition metal compound (B) comprises a titanium compound (a) of formula I (wherein Cp is a cyclopentadienyl group) and a zirconium compound (b) of formula II (wherein X is a halogen atom, and n is 3 or 4), and said organometallic compound (B) is an aluminoxane obtained by reacting a trialkylaluminum of formula III (wherein R<3> is methyl or ethyl) with water. The polymerization of an olefin in this process is usually performed not only in a liquid phase polymerization process in a hydrocarbon medium but also in a vapor phase polymerization process. The polymerization temperature is usually -70-250 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for producing polyolefin.

[Prior art]

Methods for producing polyolefins using soluble transition metal compounds and organometallic compounds are known. A method for producing polyolefins using the compound is described. On the other hand, JP-A-61-130
No. 314 produces poly-α-olefins with a high proportion of isotactic structure by polymerizing propylene and higher 1-olefins in the presence of a catalyst system consisting of a special zircon-chelate compound and oligomeric aluminoxane. It is stated that it can be obtained.

[Problem that the invention seeks to solve]

However, although the former catalyst system has very high activity against α-olefins such as ethylene and propylene, it has an active structure when polymerizing propylene and higher l-olefins. Only polypropylene can be obtained. Furthermore, in the latter catalyst system, the zircone-chelate compound described as a transition metal compound is complicated to synthesize and is difficult to obtain easily.

[Means for solving problems]

The present inventors have conducted intensive studies on a method for polymerizing α-olefins using a catalyst made of a transition metal compound and an organometallic compound. The present invention was completed by discovering that a polyolefin with a large proportion of isotactic structure can be obtained by polymerizing α-olefin.

That is, the present invention provides a method for producing a poly-α-olefin by polymerizing an α-olefin using (A) a transition metal compound and (B) an organometallic compound, in which (A) as the transition metal compound, (a) General formula (Cp) gTiclg [wherein, C
p represents a cyclopentadienyl group. ] and (b) a titanium compound represented by the general formula ZrXn [wherein, X represents a halogen atom, or n is 3 or 4
It is. ] Using two types of transition metal compounds of the zirconium compound represented by (B), the general formula AI! , R3° (in the formula, R3 represents a methyl group or an ethyl group) is characterized by using an aluminoxane obtained by the reaction of trialkylaluminum and water.

Of the catalysts used in the present invention, the transition metal compound as component (A) is composed of component (a) and (b) as described above.
The component (a) is (Cp).
It is a titanium compound represented by diclz, and is a bis(cyclopentagenyl) titanium dichloride that has two cyclopentadienyl groups and further has two chlorine atoms.

Component (b) is a zirconium compound represented by ZrXn, specifically zirconium trifluoride, zirconium tetrafluoride, zirconium trichloride, zirconium tetrachloride, zirconium tribromide, zirconium tetrabromide, Examples include zirconium iodide and zirconium tetraiodide.

The organometallic compound (B) used in the method of the present invention is a reaction product of a trialkylaluminum compound represented by the general formula AIR3x [wherein R3 represents a methyl group or an ethyl group] and water. Aluminoxane can be used.

There are no particular restrictions on the method for producing this aluminoxane, for example, in an organic solvent using the general formula Aj! A method of directly reacting trialkylaluminum represented by Rs with water dissolved in a liquid, solid, steam, or solvent, or a compound containing adsorbed water or water of crystallization, such as copper sulfate hydrate, aluminum sulfate hydrate A method of producing the compound by reacting it with trialkylaluminium in an organic solvent is mentioned.

The structure of the aluminoxane obtained by these reactions is probably represented by the general formula % [wherein R3 represents a methyl group or an ethyl group].

m is an integer from 1 to 50] and a trialkylaluminum compound represented by the general formula AlRh.

In the method of the present invention, the monomer is CH,=CHR'C, where R4 represents a hydrocarbon residue having 1 to 10 carbon atoms. ] is used for polymerization. Specifically, propylene, butene-1
, pentene-1, hexene-1, and styrene. Among them, it is particularly advantageous to use propylene, and it is also possible to use a mixture of two or more α-olefins in the polymerization, in which case it is also preferable to use ethylene as one of the olefins.

In the process of the invention, the polymerization of the olefin is usually carried out in a liquid phase polymerization process in a hydrocarbon medium, but it can also be carried out in a gas phase polymerization process. Polymerization temperature is -70°C to 250°C
1 Preferably in the range of -10°C to 200°C.

The ratio of the transition metal compound used when carrying out the present invention by the liquid phase polymerization method is as follows: The concentration of the titanium compound (CI) iTiclg is 10-" to 10-' gram atom/j2, preferably 10-7 to 104 gram atom/j2. l range,
In addition, the concentration of the zirconium compound ZrXn is 1O-
It ranges from 8 to 10 grams/l, preferably from 10<-7> to 10<-1> grams/l. Titanium compound (Cp) zTich and zirconium compound Zr
The ratio of Xn used is 1 to 10', preferably 2 to 10, as a ratio of zirconium atoms to titanium atoms.
The range is 3. Further, the proportion of the organometallic compound to be used is in the range of 10 to 10'' gram atom/i, preferably 104 to 10' gram atom/i as the concentration of aluminum atoms, and the ratio of aluminum atoms to zirconium atoms is in the range of 10 to 10'' gram atom/i. The molecular weight of the polymer, which is preferably in the range of 10 to 106, can be adjusted by adding hydrogen and/or changing the polymerization temperature.

〔Example〕

The method of the present invention will be explained in more detail below with reference to Examples.

Example-1 (a) Preparation of methylamine 0.5 mol of 25 g of copper sulfate pentahydrate (CuSOa 5HzO) was placed in 22 glass flasks which were sufficiently purged with nitrogen.
of HfO) and toluene 400Id,
After cooling to -5°C, trimethylaluminum 401d (0.42 mol) diluted with 200ml of toluene was added dropwise. After the completion of the dropwise addition, the reaction was carried out at -5°C for 24 hours, and then 25°C
After the reaction, the solid portion was removed by filtration, and the pressure was further reduced to remove toluene, thereby obtaining 15 g of a white solid component. The molecular weight measured by freezing point depression method in benzene was 490.

(Preparation of bl transition metal catalyst components In a 200 d glass flask that was sufficiently purged with nitrogen, 100 d of toluene, 1 mmol of bis(cyclopentadienyl)zirconium dichloride, and 1 mol of zirconium tetrachloride were added.
A transition metal catalyst component was obtained by charging 2 mmol and stirring at room temperature for 2 hours.

(C) Polymerization A glass autoclave with an internal volume of 1N that was sufficiently purged with nitrogen was charged with 40 ml of toluene, and the temperature was adjusted to 25°C. Then, 13 ma+ol of methylaminoxane and the above catalyst components were added in an amount of O, lsmol in terms of titanium atoms. Ta.

Furthermore, propylene was introduced to initiate polymerization. 5g/
After polymerizing with cti-G for 1 hour, the catalyst was removed by pouring the polymerization solution into a large amount of methanol acidified with hydrochloric acid.

The produced polypropylene was filtered, washed several times with methanol, and dried under reduced pressure at 60°C.

The yield of white powdered polypropylene is 160I1g, so the catalytic activity is 132g(PP)/mol(
Zr) ・Hr. Moreover, the obtained polypropylene is It? As a result of analysis, it was found to be isotactic polypropylene with an isotoughness of 83%.

Example-2 Propylene polymerization was carried out in the same manner as in Example-1 except that the polymerization temperature was changed to 80°C. The results of the zero polymerization in which white powdery polypropylene was obtained are shown in the table.

Example 3 Polymerization was carried out in the same manner as in Example 1, but the proportions of catalyst components used were changed as shown in the table. The results of polymerization in which white powdery polypropylene was obtained are shown in the table.

Comparative Example 1 Propylene polymerization was carried out in the same manner as in Example 3 except that ZrcLa was not used at all. The obtained polypropylene was an active polypropylene.

Comparative Example-2 Zrcla 1mm without using Cp or Ticlg at all
Polymerization of propylene was carried out using only 15 mmol of methylaluminoxane and 15 mmol of methylaluminoxane as a catalyst, but almost no polymer was obtained.

〔Effect of the invention〕

The method of the present invention is characterized in that it is possible to provide a method for producing a poly-α-olefin with a high proportion of isotactic structure using a commercially available transition metal compound. ing.

[Brief explanation of the drawing]

FIG. 1 is a flowchart diagram to aid understanding of the present invention. Patent applicant Mitsui Toatsu Chemical Co., Ltd.

Claims (1)

[Scope of Claims] In a method for producing a poly-α-olefin by polymerizing an α-olefin using (A) a transition metal compound and (B) an organometallic compound, as the transition metal compound (a) General formula (Cp)_2TiCl_2 [wherein, Cp represents a cyclopentadienyl group]. ] and (b) a titanium compound represented by the general formula ZrX_n [wherein, X represents a halogen atom. Also, n is 3 or 4
It is. ] Two types of transition metal compounds of zirconium compounds represented by (B) are used to form the organometallic compound of the general formula AlR^3_3 [wherein R^3 represents a methyl group or an ethyl group. ] A method for producing a poly-α-olefin, characterized by using an aluminoxane obtained by the reaction of trialkylaluminum represented by the following formula with water.