JPH0363962B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for polymerizing or copolymerizing olefins in the presence of a catalyst formed from a low atom trivalent titanium compound soluble in a hydrocarbon medium, a magnesium compound having an organic group, and an organoaluminum compound, and furthermore, This invention relates to a method for producing a polymer with a narrow molecular weight distribution. In the present invention, the term "polymerization" is sometimes used to include copolymerization, and similarly, the term "polymer" is sometimes used to include copolymers. Many proposals are known regarding supported highly active transition metal compound components in which transition metal compounds are supported on various magnesium compounds. Usually, it is necessary to prepare the supported catalyst component prior to the polymerization of olefins. Furthermore, since the supported catalyst component is insoluble in the hydrocarbon solvent for polymerization, special considerations are required to quantitatively charge the catalyst component into the polymerization vessel or to achieve uniform dispersion in the polymerization vessel. be. And even with such consideration,
The use of the above-mentioned insoluble catalyst components often results in the disadvantage that the resulting polymer is non-uniform. In order to avoid the above-mentioned disadvantages, a method for highly active polymerization of olefins using a soluble magnesium compound as a polymerization catalyst was proposed in Japanese Patent Publication No. 46-15635 and Japanese Patent Publication No. 46-15635.
This method has been proposed in Japanese Patent Publication No. 46-31968 and Japanese Patent Publication No. 50-39117. However, the degree of yield increase brought about by using a magnesium compound in these proposals is within about 10 times compared to the case without the use of a magnesium compound, and the above-mentioned carriers with the disadvantages mentioned above are It was hard to say that it was comparable to the catalyst component. In particular, the above-mentioned special public service No. 50-39117
The proposal in the publication discloses a method in which various magnesium compounds are dissolved and used. For example, regarding magnesium chloride, a method is disclosed in which it is used by dissolving it in an organoaluminum compound. However, it has been shown that the polyethylene yield increase achieved by using such magnesium compounds is at most a little less than 3 times (Examples 27-30 of the proposal). The present inventors have found that the present inventors have a high activity that is at least as good as the high activity achieved by using a catalyst component that is insoluble in the hydrocarbon solvent for polymerization described above;
Further, research was conducted to overcome the above-mentioned disadvantages in the use of the insoluble catalyst components proposed in the past. As a result, by using a catalyst formed from a trivalent titanium compound component soluble in a hydrocarbon medium as a polymerization solvent, a magnesium compound component soluble in a hydrocarbon medium having an organic group, and an organoaluminum compound, the above-mentioned The present invention was achieved by discovering that a polymer with higher activity and narrower molecular weight distribution can be obtained compared to conventional catalyst systems proposed in prior art documents. Accordingly, an object of the present invention is to provide a method for polymerizing olefins using a novel catalyst for olefin polymerization formed from components soluble in a hydrocarbon as a polymerization medium. Another object of the present invention is to provide a production method capable of producing a polymer having high polymerization activity and a narrow molecular weight distribution. The above objects and many other objects and advantages of the present invention will become more apparent from the following description. To summarize the present invention, the present invention comprises: (A) a trivalent titanium compound made soluble in a hydrocarbon medium by an electron donor; (B) having an organic group represented by the following formula; A magnesium compound soluble in the polymerization medium, (R ¹ ) _o Mg(R ² ) _2-o (where R ¹ and R ² represent a hydrocarbon group, an alkoxyl group, an aryloxy group, or an ester group, and n is (a positive number satisfying 0<n≦2.) and (C) an organoaluminum compound, a method for polymerizing olefin, characterized by polymerizing or copolymerizing olefin in the presence of a catalyst formed from: The main points are as follows. The titanium compound component (A) of the catalyst component used in the method of the present invention is a trivalent titanium compound component solubilized in a hydrocarbon medium with an electron donor, specifically titanium tetrachloride. TiCl ₃・T type reduced with titanium metal, TiCl ₃・A type reduced with aluminum metal, TiCl ₃・H reduced with hydrogen
Type, (C ₂ H ₅ ) ₃ Al, (C ₂ H ₅ ) ₂ AlCl, (C ₂ H ₅ ) _{1.5 ,}
Titanium trihalides _, such as _TiCl3 , reduced with organoaluminium compounds such as _AlCl1.5
(OCH ₃ ) ₃ , Ti (OC ₂ H ₅ ) ₃ , Ti (OC ₄ H ₉ ) ₃ , Ti
(OCH ₃ )Cl ₂・2CH ₃ OH, Ti(OCH ₃ ) ₂ Cl・
Examples include alkoxytitanium () compounds such as CH ₃ OH. An electron donor is used in the solubilization treatment of the trivalent titanium compound, and an oxygen-containing electron donor or a nitrogen-containing electron donor is suitable as the electron donor. As a method for solubilizing a trivalent titanium compound in a hydrocarbon medium, the electron donor is usually about 0.5 to about 60 mol, preferably about 3 to about 60 mol, per gram atom of titanium in the trivalent titanium compound. A method of contacting in a hydrocarbon medium in a range of about 20 moles is employed. In some cases, only a portion of the trivalent titanium compound is dissolved, and in that case, it is preferable to separate and use only the solubilized portion. The temperature during contact is usually about 0 to about 200°C, preferably about
The temperature ranges from 20 to about 150°C. Alcohols, ethers, esters, carboxylic acids, aldehydes, etc. are used as the oxygen electron donor, and amines, amides, etc. are used as the nitrogen electron donor. Specifically, the oxygen electron donor is preferably an alcohol having 6 carbon atoms.
Examples of the above alcohols include aliphatic alcohols such as 2-methylpentanol, 2-ethylbutanol, n-heptanol, n-octanol, 2-ethylhexanol, decanol, dodecanol, tetradecyl alcohol, undecenol, oleyl alcohol, and stearyl alcohol. , cyclohexanol, alicyclic alcohols such as methylcyclohexanol, aromatic alcohols such as benzyl alcohol, methylbenzyl alcohol, isopropylbenzyl alcohol, α-methylbenzyl alcohol, α,α-dimethylbenzyl alcohol, n-butyl cellosolve,
Examples include aliphatic alcohols containing alkoxyl groups such as 1-butoxy-2-propanol, and other alcohols include alcohols having 5 or less carbon atoms such as methanol, propanol, butanol, ethylene glycol, and methyl carbinol. be able to. As the ether, for example, di-n-hexyl ether, di-n-octyl ether, di-n-decyl ether, etc. can be used. The carboxylic acid has 7 or more carbon atoms, preferably 7 to 20 carbon atoms, and specific examples of the carboxylic acid include caprylic acid, 2-ethylhexanoic acid, nonylic acid, capric acid, undecylenic acid, oleic acid, etc. can be exemplified.
The aldehyde has 7 or more carbon atoms, preferably 7 to 20 carbon atoms, and specific examples thereof include capryaldehyde, 2-ethylhexylaldehyde, decylaldehyde, and undecylaldehyde. Furthermore, the amine has 7 or more carbon atoms, preferably 7 or more carbon atoms.
Specific examples include heptylamine, octylamine, nonylamine, decylamine, laurylamine, undecylamine, 2-
Examples include ethylhexylamine. The magnesium compound component (B) of the catalyst component used in the method of the present invention is a magnesium compound having an organic group, more specifically, at least one organic group such as a hydrocarbon group, an alkoxyl group, or an ester. Typical compounds have the general formula (R ¹ ) _o Mg(R ² ) _2-o (R ¹ is a hydrocarbon group, an organic group such as an alkoxyl group, an aryloxy group, an ester group, R ² is an organic group or halogen, etc., n is 0<n≦2), and magnesium compounds soluble in the polymerization medium include diisopropylmagnesium, dibutylmagnesium, dinormalhexylmagnesium, didecylmagnesium, and dicyclohexylmagnesium. , dialkyl (or diaryl) magnesium such as diphenylmagnesium, n-butyl ethylmagnesium, n-butyl n-octylmagnesium, alkyl (or aryl)magnesium halides such as isobutylmagnesium chloride, butylisopropoxymagnesium, dodecylbutoxymagnesium, cyclohexylbutoxy Examples include alkoxymagnesium halides such as alkyl(aryl)magnesium alkoxides (or aryloxides) such as magnesium. The organoaluminum compound component (C) used as a catalyst component in the method of the present invention includes:
Compounds having at least one Al-carbon bond in the molecule can be used, such as the following types of compounds. (i) General formula (R ¹ ) _n Al (OR ² ) _o HpXq (where R ¹ and R ² are usually 1 or 1 carbon atom)
15 hydrocarbon groups, preferably 1 to 4 hydrocarbon groups, which may be the same or different from each other. X is halogen, m is 0≦m<3, n is 0≦n<3, p is 0≦
p<3, q is a number of 0≦q<3, and m
+n+p+q=3), (ii) with the general formula M ¹ Al(R ¹ ) ₄ (where M ¹ is Li, Na or K, and R ¹ is the same as above); Complex alkylation products of the Group 1 metals represented by the above and aluminum can be mentioned. Examples of the organoaluminum compounds belonging to (i) above include the following. Organic aluminum represented by the general formula (R ¹ ) _n Al(OR ² ) _3-n (where R ¹ and R ² are the same as above. m is preferably a number of 1.5≦m<3) Compound, an organoaluminum compound represented by the general formula (R ¹ ) _n AlX _3-n (where R ¹ is the same as above, X represents a halogen, and m preferably satisfies 0<m<3), general An organoaluminum compound represented by the formula (R ¹ ) _n AlH _3-n (where R ¹ is the same as above. m is preferably 2≦m<3), a general formula (R ¹ ) _n Al( OR ² ) _o X _q (Here, R ¹ and R ² are the same as above.
<3 and m+n+q=3). Among the aluminum compounds belonging to (i), more specifically, trialkyl aluminum such as triethyl aluminum and tributyl aluminum,
In addition to trialkenylaluminums such as triisoprenylaluminum, dialkylaluminum alkoxides such as diethylaluminum ethoxide, dibutylaluminum butoxide, alkylaluminum sesquialkoxides such as ethylaluminum sesquiethoxide, butylaluminum sesquibutoxide, etc. with the general formula R ¹ ₂ Partially alkoxylated alkylaluminums, dialkylaluminum halides such as diethylaluminum chloride, dibutylaluminum chloride, diethylaluminum bromide, ethylaluminum halides, with an _average composition expressed as _0.5Al ( ^OR2 ), _etc. Partially halogenated sesquichloride, alkylaluminum sesquihalogenides like butylaluminum sesquichloride, ethylaluminum sesquibromide, alkylaluminum dihalides like ethylaluminum dichloride, propylaluminum dichloride, butylaluminum dibromide etc. alkylaluminum, diethylaluminum hydride,
Dialkyl aluminum hydrides such as dibutyl aluminum hydride, partially hydrogenated alkylaluminums such as alkyl aluminum dihydrides such as ethyl aluminum dihydride, propyl aluminum dihydride, ethyl aluminum ethoxy chloride, butyl aluminum butoxy chloride, ethyl aluminum ethoxy bromide partially alkoxylated and halogenated alkyl aluminums such as Also
A compound similar to (i) may be an organoaluminum compound in which two or more aluminum atoms are bonded via an oxygen atom or a nitrogen atom. Examples of such compounds include (C ₂ H ₅ ) ₂ AlOAl(C ₂ H ₅ ) ₂ , (C ₂ H ₉ ) ₂ AlOAl(C ₄ H ₉ ) ₂ ,

[Formula] etc. can be exemplified. Further, these exemplified compounds may be used in combination. Compounds belonging to (ii) above include LiAl
Examples include (C ₂ H ₅ ) ₄ and LiAl(C ₇ H ₅ ) ₄ . Among these, it is particularly preferable to use trialkyl aluminum and alkyl aluminum halide. In the method of the present invention, olefins used for polymerization include ethylene, propylene, 1-butene, 4-methyl-1-pentene, 1-octene, etc., and these can be used not only for homopolymerization but also for random copolymerization, block copolymerization, etc. It can be performed. In copolymerization, polyunsaturated compounds such as conjugated dienes and non-conjugated dienes can be selected as copolymerization components. Polyunsaturated compounds such as butadiene, isobutylene, 1,4-hexadiene, dicyclopentadiene, 5-ethylidene-2-norbornene,
When copolymerizing 1,7-octadiene etc., approximately
It may be copolymerized in a proportion of about 0.1 to about 10 mol%, preferably about 0.2 to about 5 mol%. In this case, the resulting copolymer has an iodine value of about 5 to about 50, and can be sulfur-cured. Its vulcanized properties are also excellent, and it can be used as a vulcanized rubber with high strength. The resulting polyolefin may be resinous or rubbery. According to the method of the present invention, a polymer having higher activity than conventional soluble titanium catalysts and having a narrow molecular weight distribution (w/n) can be obtained. In the present invention, polymerization is carried out in a hydrocarbon liquid medium using the above catalyst components. As a hydrocarbon liquid medium,
Aliphatic hydrocarbons and their halogen derivatives such as pentane, hexane, heptane, octane, decane, dodecane, and kerosene; Alicyclic hydrocarbons and their halogen derivatives such as cyclohexane, methylcyclopentane, and methylcyclohexane; benzene, toluene, aromatic hydrocarbons such as xylene and their halogen derivatives such as chlorobenzene;
can be exemplified. Moreover, the olefin itself used for polymerization can also be used as a liquid medium. In the method of the present invention, the proportions of each catalyst component used are as follows. The amount of the soluble trivalent titanium compound component (A) used is the soluble trivalent titanium compound component (A)/organic group-containing magnesium compound component (B).
The molar ratio is preferably from about 0.005 to about 1, more preferably from about 0.01 to about 0.33, even more preferably from about 0.033 to about 0.25.
The concentration of the transition metal compound per liquid phase is preferably about 0.0005 to about 1 milligram atom, more preferably about 0.001 to about 1 milligram atom in terms of transition metal.
The concentration of the organic group-containing aluminum compound component (B) is preferably about 0.0005 to about 200 milligram atoms, more preferably about 0.003 to about 50 milligram atoms, in terms of magnesium atoms.
It is best to choose milligram atoms. On the other hand, the organoaluminum compound component (C) must be added at least in an amount that will not be deactivated by alcohol or the like, and usually contains about 5 to about 2000 g atoms of aluminum per 1 g atom of the transition metal. Preferably, about 20 to about 500 gram atoms are used. In the present invention, it is possible to adopt a continuous polymerization method in which olefins are continuously supplied to the polymerization system and hydrocarbons containing the polymer are continuously discharged from the polymerization system, or a semi-continuous method or a batch method can be adopted. can also be adopted. In the present invention, the method of adding each of the catalyst components (A), (B), and (C) is arbitrary; each may be separately supplied to the polymerization system, or any of the components may be premixed in advance. You can leave it there. For example, (B) and (C) may be premixed and the resulting solid component may be used. Furthermore, instead of preparing (A) and (B) separately, the low-valent titanium compound and the hydrocarbon-insoluble magnesium compound may be simultaneously solubilized using the electron donor. FIG. 1 shows a flowchart showing the steps for preparing a catalyst according to the present invention. In the process of the present invention, the temperature during polymerization or copolymerization of the olefin is generally from about 20 to about
300°C, preferably about 65 to about 200°C. In particular, in order to produce a polyolefin with good transparency in the copolymer production method, it is preferable to perform liquid phase polymerization using an inert hydrocarbon medium and select a temperature at which the polyolefin dissolves. For example, when a resinous copolymer is produced by copolymerizing ethylene with a small proportion of another α-olefin, the temperature is preferably from the melting point of the copolymer to about 200°C. In addition, the polymerization pressure is from atmospheric pressure to about 100
Kg/cm ² -G, especially atmospheric pressure or about 50Kg/cm ² -
It is preferable to set it as G. In carrying out the present invention, hydrogen, organometallic compounds of Group 2 metals in the periodic table, and/or various electron donors other than the above, such as alcohols, ethers, Esters, amines, ketones, carboxylic acids, amides, phosphorus compounds, sulfur compounds, acid anhydrides, etc. may also be present. Next, a more detailed explanation will be given with reference to Examples. Example 1 () Catalyst synthesis A thermometer, nitrogen injection tube, dropping funnel, and Dimroth cooling tube were attached to a sufficiently dried 200 ml four-necked round-bottomed flask, the air was sufficiently purged with nitrogen, and the round-bottomed flask was filled with TiCl ₃ (Toho Manufactured by Titanium, product name
Add TAC-131) 5.0mM and 50ml of n-decane, and then add 2-ethylhexanol (hereinafter abbreviated as EHA).
45mM of was added and stirred at 80°C for 1 hour to obtain a blue-green homogeneous solution. () Copolymerization A stirring blade, a gas blowing tube, a thermometer, a cooling tube, and a dropping funnel were attached to a sufficiently dried separable flask No. 1, and the flask was sufficiently purged with nitrogen. 250 ml of n-decane, which had been dehydrated and dried using a molecular sieve, was placed in this flask. Nitrogen flow into the dropping funnel ()
The titanium catalyst synthesized by is 0.0125mM in terms of titanium.
(0.05mM/) and 0.375mM (1.5mM/) of diethylaluminium chloride was added to the flask. Dry ethylene 120 through gas blow pipe
/hr and propylene for 180hr was passed through a flask whose temperature was controlled at 70°C for 10 minutes. (n-
C ₆ H ₁₃ ) ₂ Mg converted to Mg is 0.125mM (0.5mM/)
After adding it to the flask, a titanium catalyst was added dropwise to start copolymerization, and the copolymerization was carried out at 70°C for 30 minutes. Copolymerization was terminated by adding 10 ml of butyl alcohol to the polymerization solution. After polymerization is complete, pour the polymerization solution into a large amount of acetone and methanol mixture,
A copolymer was obtained. The yield of the copolymer was 23.4 g, and the ethylene (hereinafter sometimes abbreviated as C ₂ ″) composition in the copolymer was 59.5 mol%.
℃ Intrinsic viscosity measured in decalin (hereinafter, [η])
It is sometimes abbreviated as. ) was 1.45 dl/g.
In addition, the molecular weight distribution of the copolymer (Mw/GPC
Mn, hereinafter sometimes simply abbreviated as Mw/Mn. )
was 5.0. The molecular weight distribution of the ethylene copolymer was measured according to "Gel Permeation Chromatography" written by Takeuchi and published by Maruzen. Comparative Example 1 Example 1 was carried out in the same manner as in Example 1, except that TiCl ₃ was used as it was as a titanium catalyst without performing catalyst synthesis, but the TiCl ₃ polymerization activity was very low, and it was not possible to evaluate the polymer properties. Ta. Comparative Example 2 In Example 1, TiCl ₃ was used as it was as a titanium catalyst without performing catalyst synthesis, and (n-
C ₆ H ₁₃ ) ₂ Except for not using Mg,
The same procedure as in Example 1 was carried out. The polymerization activity was very low, and the properties of the polymer could not be evaluated. Comparative Example 3 The same procedure as in Example 1 was carried out except that (n-C ₆ H ₁₃ ) ₂ Mg was not used, but almost no polymerization activity was shown, and therefore the polymer properties were I couldn't even evaluate it. Comparative Example 4 Example 1 was carried out in the same manner as in Example 1, except that TiCl ₄ was used as the titanium catalyst without performing catalyst synthesis. The yield of the copolymer was 15.6 g, its C ₂ ″ composition was 59.4 mol%, [η] was 1.44 dl/g,
Mw/Mn was 7.5. Comparative Example 5 () Synthesis of hydrocarbon-soluble Mg compound 50 g of commercially available anhydrous magnesium chloride was suspended in 1 part of n-decane under a nitrogen atmosphere, and 205 g of 2-ethylhexyl alcohol (3 times the mole relative to magnesium chloride) was added. The temperature was gradually raised while stirring, and the reaction was carried out at 130°C for 1 hour. The magnesium solid disappeared completely, and a colorless and transparent liquid was obtained. Even when this solution was cooled to room temperature, no solid precipitated and it remained a colorless and transparent solution. Thus, a solubilized magnesium chloride-2-ethylhexyl alcohol complex was obtained (hereinafter referred to as Mg liquid). () Copolymerization In Example 1, instead of (n-C ₆ H ₁₃ ) ₂ Mg, the Mg solution obtained in () was changed to 0.25mM in terms of Mg, and the titanium catalyst and diethylaluminium chloride were each added at 0.025mM. Example 1 was carried out in the same manner as in Example 1, except that the mixture was changed to use 1.5 mM and 1.5 mM, and a mixed gas of 90/hr of ethylene and 210/hr of propylene was used. The yield of the copolymer was 4.0 g, its C ₂ ″ composition was 61.2 mol%, and [η] was 2.51 dl/g. Examples 2 to 10 In the catalyst synthesis of Example 1, EHA The same procedure as in Example 1 was carried out except that the compounds shown in Table 1 were used instead.The results are shown in Table 1.

[Table] Example 12 In the copolymerization of Example 1, (n-C ₆ H ₁₃ ) ₂ Mg
Except that n-C ₄ H ₉ Mg C ₂ H ₅ was used instead of
The same procedure as in Example 1 was carried out. The yield of copolymer is
23.2g, its C ₂ ″ composition is 60.1mol%,
[η] was 1.50 dl/g, and Mw/Mn was 5.1. Example 13 Example 1 except that n-C ₄ H ₉ Mg Cl was used instead of (n-C ₆ H ₁₃ ) ₂ Mg and 0.75 mM of ethylaluminum sesquichloride was used. It was done in the same way as 1. In addition, n
-C ₄ H ₉ Mg Cl is n- in n-decane solvent
Add 3 times the mole of EHA to C ₄ H ₉ Mg Cl and heat at 130℃ for 1 hour.
After stirring to obtain a homogeneous solution, it was used for polymerization. The yield of the copolymer was 23.0 g, and its C ₂ ″ composition was
61.0 mol%, [η] is 1.48 dl/g,
Mw/Mn was 5.2. Example 14 In Example 13, Mg compound (C ₂ H ₅ O)
The same procedure as in Example 13 was carried out except that Mg Cl was used. Note that (C ₂ H ₅ O)Mg Cl was used after adding EHA in an amount 3 times the mole of (C ₂ H ₅ O)Mg Cl in n-decane solvent and stirring at room temperature for 1 hour to make a homogeneous solution. The yield of copolymer is 22.5 g, and its C ₂ ″ composition is
60.5 mol%, [η] is 1.62 dl/g,
Mw/Mn was 5.1. Example 15 Example 13 was carried out in the same manner as in Example 13, except that the Mg compound was changed to a homogeneous solution of magnesium stearate in n-decane (obtained by reacting in n-decane solvent at 130°C for 1 hour). . The yield of copolymer is
21.5g, its C ₂ ″ composition is 60.1mol%,
[η] was 1.64 dl/g, and Mw/Mn was 5.3. Example 16 In Example 1, 7.5(n- _C6H13 ) _2Mg , which is a complex of di-n-butylmagnesium and triethylaluminum, was used instead of (n- _C6H13 )2Mg.
Example 1 except that C ₄ H ₉ ) ₂ Mg・(C ₂ H ₅ ) ₃ Al was used.
I went in the same way. The yield of the copolymer was 23.6 g, its C ₂ ″ composition was 60.7 mol%, and [η] was
It was 1.42 dl/g, and Mw/Mn was 5.1. Example 17 In the copolymerization of Example 1, 5-ethylidene-
2-norbornene 0.25g and titanium catalyst
Add 0.0125mM of (n-C 6 H 13 ) 2 Mg to the dropping funnel, change to add 0.375mM of diethylaluminum chloride to the flask, and add 0.125mM of (n-C ₆ H ₁₃ ) ₂ Mg.
Example 1 was carried out in the same manner as in Example 1, except for adding the following. The yield of the copolymer was 15.2 g, its C ₂ ″ composition was 62.3 mol%, [η] was 1.60 dl/g, and the iodine number was 5.7. Example 18 In Example 17, The same procedure as Example 17 was carried out except that 5-ethylidene-2-norbornene was changed to dicyclopentadiene.The yield of the copolymer was 14.0
g, its C ₂ ″ composition is 63.4 mol%, [η]
was 1.73 dl/g, and the iodine value was 5.6. Example 19 Instead of TiCl ₃ (TAC-131) in Example 1,
The same procedure as in Example 1 was carried out except that a Ti compound obtained by reducing TiCl ₄ with Et ₃ Al was used. The yield of copolymer is 22.3g, and its C ₂ ″ composition is
60.3 mol%, [η] is 1.36 dl/g,
Mw/Mn was 5.2. Note that the reduction of TiCl ₄ with Et ₃ Al was performed as follows. 200ml thoroughly dried and replaced with nitrogen
50mM of _TiCl4 and 50mM of n-hexane in a three-necked flask.
ml of Et ₃ Al and 25mM of TiCl at 0℃ under stirring _.
It was gradually added dropwise over 1 hour, the temperature was raised to 20°C over 1 hour, and the mixture was aged at 20°C for 2 hours. The precipitated solid was filtered out,
The mixture was thoroughly washed with n-hexane and then filtered to obtain a reddish-purple solid.

[Brief explanation of drawings]

FIG. 1 is a flowchart showing the steps for preparing a catalyst according to the present invention.

Claims (1)

[Scope of Claims] 1 (A) A trivalent titanium compound made soluble in a hydrocarbon medium by an electron donor; (B) A trivalent titanium compound having an organic group represented by the following formula and soluble in a polymerization medium. Soluble magnesium compound, (R ¹ ) _o Mg(R ² ) _2-o (where R ¹ and R ² represent a hydrocarbon group, an alkoxyl group, an aryloxy group, or an ester group, and n is 0<n A positive number satisfying ≦2.) and (C) an organoaluminum compound.