JP6886858B2 - Oligomer production method - Google Patents

Description

The present invention relates to a method for producing an oligomer, and more particularly to a method for producing an oligomer from ethylene.

As a catalyst used for copolymerization of ethylene and α-olefin, a catalyst composed of a metallocene compound and methylaluminoxane, a palladium-based catalyst, an iron complex, a cobalt complex and the like are known (Non-Patent Documents 1 to 3 and Patent Documents). 1-3).

The iron complex is also known as a catalyst for ethylene polymerization (Non-Patent Documents 4 to 6).

Further, as a catalyst for producing a block copolymer, a catalyst composed of diethylzinc, a metallocene compound, a palladium-based catalyst and dialkylzinc is known (Non-Patent Documents 7 and 4).

Special Table 2000-516295 JP-A-2002-302510 Chinese Patent Application Publication No. 102432415 Special Table 2007-528616

"Macromol. Chem. Phys.", Vol. 197, 1996, p. 3907 "J. Am. Chem. Soc.", Vol. 117, 1995, p. 6414 "J. Am. Chem. Soc.", Vol. 120, 1998, p. 7143 "J. Mol. Cat. A: Chemical", Vol. 179, 2002, p. 155 "Appl. Cat. A: General", Vol. 403, 2011, p. 25 "Organometallics", Vol. 28, 2009, p. 3225 "Science", Vol. 312, 2006, p. 714

An object of the present invention is to provide a method for producing an oligomer capable of efficiently obtaining an oligomer having a desired molecular weight in the oligomerization of ethylene.

That is, the present invention includes (A) a rac-ethylidene indenyl zirconium compound represented by the following general formula (1), (B) an iron compound represented by the following general formula (2), (C) methylaluminoxane and /. Alternatively, the present invention provides a method for producing an oligomer, which comprises a step of oligomerizing ethylene in the presence of a catalyst containing a boron compound and (D) an organozinc compound and / or an organoaluminum compound other than methylaluminoxane.

［式（１）中、Ｘはハロゲン原子、水素原子または炭素数１〜６のヒドロカルビル基を示す。］

[In the formula (1), X represents a halogen atom, a hydrogen atom or a hydrocarbyl group having 1 to 6 carbon atoms. ]

［式（２）中、Ｒは炭素数１〜６のヒドロカルビル基または炭素数６〜１２の芳香族基を示し、同一分子中の複数のＲは同一でも異なっていてもよく、Ｒ’は酸素原子および／または窒素原子を有する炭素数０〜６の遊離基を示し、同一分子中の複数のＲ’は同一でも異なっていてもよく、Ｙは塩素原子または臭素原子を示す。］

[In formula (2), R represents a hydrocarbyl group having 1 to 6 carbon atoms or an aromatic group having 6 to 12 carbon atoms, and a plurality of Rs in the same molecule may be the same or different, and R'is oxygen. It represents a free radical having 0 to 6 carbon atoms with an atom and / or a nitrogen atom, and a plurality of R'in the same molecule may be the same or different, and Y represents a chlorine atom or a bromine atom. ]

According to the above-mentioned production method of the present invention, in the oligomerization of ethylene, the obtained oligomer can be efficiently improved to a desired molecular weight, and the progress of polymerization can be sufficiently suppressed.

In the above production method, the number average molecular weight (Mn) of the obtained oligomer can be 200 to 5000.

The organic aluminum compound is from the group consisting of trimethylaluminum, triethylaluminum, triisopropylaluminum, tripropylaluminum, tributylaluminum, triisobutylaluminum, trihexylaluminum, triphenylaluminum, diethylaluminum chloride, ethylaluminum dichloride and ethylaluminum sesquichloride. It can be at least one selected.

The organozinc compound can be at least one selected from the group consisting of dimethylzinc, diethylzinc and diphenylzinc.

The boron compounds are trispentafluorophenylborane, lithium tetrakispentafluorophenylborate, sodium tetrakispentafluorophenylborate, N, N-dimethylanilinium tetrakispentafluorophenylborate, trityltetrakispentafluorophenylborate, and lithium tetrakis (3,5). -At least one selected from the group consisting of trifluoromethylphenyl) borate, N, N-dimethylanilinium tetrakis (3,5-trifluoromethylphenyl) borate and trityltetrakis (3,5-trifluoromethylphenyl) borate. Can be.

According to the present invention, it is possible to provide a method for producing an oligomer capable of efficiently obtaining an oligomer having a desired molecular weight in the oligomerization of ethylene.

Hereinafter, preferred embodiments of the present invention will be described in detail.

[catalyst]
The catalyst for ethylene oligomerization according to the present embodiment is (A) rac-ethylidene indenyl zirconium compound, (B) iron compound, (C) methylaluminoxane and / or boron compound, and (D) organic. Includes zinc compounds and / or organoaluminum compounds other than methylaluminoxane.

Hereinafter, each component will be described.

<(A) rac-ethylidene indenyl zirconium compound>
In the present embodiment, the (A) rac-ethylidene indenyl zirconium compound is represented by the following general formula (1).

In formula (1), X represents a halogen atom, a hydrogen atom or a hydrocarbyl group having 1 to 6 carbon atoms. Specific examples of such compounds include rac-ethylideneindenyl zirconium dichloride, rac-ethylideneindenyl zirconium dibromide, rac-ethylideneindenyl zirconium dihydride, rac-ethylideneindenyl zirconium hydride hydride, rac-ethylideneindenyl. Examples include zirconium dimethyl. Among these, rac-ethylideneindenyl zirconium dichloride is preferable from the viewpoint of easy availability. These rac-ethylidene indenyl zirconium compounds may be used alone or in combination of two or more.

<(B) Iron compound>
In the present embodiment, the iron compound (B) is represented by the following general formula (2).

In the formula (2), R represents a hydrocarbyl group having 1 to 6 carbon atoms or an aromatic group having 6 to 12 carbon atoms, and a plurality of Rs in the same molecule may be the same or different. Specific examples of R include a methyl group, a phenyl group and the like. R'represents a free radical having 0 to 6 carbon atoms having an oxygen atom and / or a nitrogen atom, and a plurality of R'in the same molecule may be the same or different. Specific examples of R'are: hydrogen atom, methoxy group, ethoxy group, isopropoxy group, nitro group, methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, tertiary butyl group, hexyl group, Examples thereof include a phenyl group and a cyclohexyl group. Y represents a chlorine atom or a bromine atom. Specific examples of such compounds include compounds represented by the following general formulas (2a) to (2h). These iron compounds may be used alone or in combination of two or more.

In the iron compound represented by the general formula (2), the diimine compound constituting the ligand (hereinafter, also simply referred to as the diimine compound) is, for example, dehydrated dibenzoylpyridine and aniline compound in the presence of an acid. It can be synthesized by condensing.

A preferred embodiment of the method for producing a diimine compound is a first step of dissolving 2,6-dibenzoylpyridine, an aniline compound, and an acid in a solvent and dehydrating and condensing them under reflux with heating of the solvent.

The reaction mixture after the first step is separated and purified to obtain a diimine compound.

As the acid used in the first step, for example, an organoaluminum compound can be used. Organic aluminum compounds include trimethylaluminum, triethylaluminum, tripropylaluminum, triisopropylaluminum, tributylaluminum, triisobutylaluminum, trihexylaluminum, trioctylaluminum, diethylaluminum chloride, ethylaluminum chloride, ethylaluminum sesquichloride, methylaluminoxane. And so on.

As the acid used in the first step, a protonic acid may be used in addition to the above-mentioned organoaluminum compound. Protonic acid is used as an acid catalyst to donate protons. The protonic acid used is not particularly limited, but is preferably an organic acid. Examples of such a protonic acid include acetic acid, trifluoroacetic acid, methanesulfonic acid, trifluoromethanesulfonic acid, paratoluenesulfonic acid and the like. When these protonic acids are used, it is preferable to remove the water with a Dean-Stark water separator or the like from the viewpoint of suppressing the by-production of water. It is also possible to carry out the reaction in the presence of an adsorbent such as molecular sieves. The amount of the protonic acid added is not particularly limited and may be a catalytic amount.

Examples of the solvent used in the first step include a hydrocarbon solvent and an alcohol solvent. Examples of the hydrocarbon solvent include hexane, heptane, octane, benzene, toluene, xylene, cyclohexane, methylcyclohexane and the like. Examples of the alcohol solvent include methanol, ethanol, isopropyl alcohol and the like.

The reaction conditions in the first step can be appropriately selected depending on the type and amount of the raw material compound, the acid and the solvent.

The separation / purification treatment in the second step is not particularly limited, and examples thereof include silica gel column chromatography and a recrystallization method. In particular, when the above-mentioned organoaluminum compound is used as the acid, it is preferable to mix the reaction solution with a basic aqueous solution to decompose and remove aluminum, and then purify the acid.

The iron compound according to this embodiment contains iron as a central metal. The method for mixing the diimine compound with iron is not particularly limited, and for example,
(I) A method of adding and mixing an iron salt (hereinafter, also simply referred to as "salt") to a solution in which a diimine compound is dissolved.
(Ii) A method of mixing a solution in which a diimine compound is dissolved and a solution in which a salt is dissolved,
(Iii) A method of physically mixing a diimine compound and a salt without using a solvent.
And so on.

Further, the method for extracting the complex from the mixture of the diimine compound and iron is not particularly limited, and for example,
(A) When a solvent is used in the mixture, the solvent is distilled off and the solid matter is filtered off.
(B) A method for filtering out the precipitate formed from the mixture,
(C) A method of adding a poor solvent to the mixture to purify the precipitate and filter it.
(D) A method for taking out the solvent-free mixture as it is,
And so on. After that, a cleaning treatment with a solvent capable of dissolving the diimine compound, a cleaning treatment with a solvent capable of dissolving the metal, a recrystallization treatment using an appropriate solvent, or the like may be further performed.

Examples of iron salts include iron (II) chloride, iron (III) chloride, iron (II) bromide, iron (III) bromide, iron (II) acetylacetone, iron (III) acetylacetone, and iron (II) acetate. ), Iron acetate (III), and the like. Those salts having a ligand such as a solvent or water may be used. Among these, the salt of iron (II) is preferable, and iron (II) chloride is more preferable.

The solvent for bringing the diimine compound into contact with iron is not particularly limited, and either a non-polar solvent or a polar solvent can be used. Examples of the non-polar solvent include hydrocarbon solvents such as hexane, heptane, octane, benzene, toluene, xylene, cyclohexane and methylcyclohexane. Examples of the polar solvent include a polar protic solvent such as an alcohol solvent and a polar aprotic solvent such as tetrahydrofuran. Examples of the alcohol solvent include methanol, ethanol, isopropyl alcohol and the like. In particular, when the mixture is used as it is as a catalyst, it is preferable to use a hydrocarbon solvent that has substantially no effect on ethylene polymerization.

Further, the mixing ratio of the diimine compound and iron when they are brought into contact with each other is not particularly limited. The lower limit of the diimine compound / iron ratio is preferably 0.2 / 1 or more, more preferably 0.3 / 1 or more, still more preferably 0.5 / 1 or more in terms of molar ratio, and the diimine compound / iron. The upper limit of the ratio is preferably 5/1 or less, more preferably 3/1 or less, still more preferably 2/1 in terms of molar ratio. The ratio of diimine compound / iron is a molar ratio, particularly preferably 1.

The two imine sites in the diimine compound are preferably E-forms, but may contain Z-form-containing diimine compounds as long as they both contain E-form diimine compounds. Since the diimine compound containing the Z-form is difficult to form a complex with a metal, it can be easily removed by a purification step such as solvent washing after forming the complex in the system.

<(C) Methylaluminoxane, boron compound>
The catalyst according to this embodiment contains (C) a methylaluminoxane and / or a boron compound.

As the methylaluminoxane, a commercially available product diluted with a solvent can be used, or a product obtained by partially hydrolyzing trimethylaluminum in a solvent can also be used. When unreacted trimethylaluminum remains in the methylaluminoxane, the unreacted trimethylaluminum may be used as the component (D) described in detail below, or trimethylaluminum and the solvent are retained under reduced pressure. It may be used as the dried methylaluminoxane removed. Further, at the time of partial hydrolysis of trimethylaluminum, modified methylaluminoxane in which trialkylaluminum other than trimethylaluminum such as triisobutylaluminum is coexisted and co-hydrolyzed can also be used. Similarly, in this case as well, if residual trialkylaluminum is present, the unreacted trialkylaluminum may be used as the component (D) described in detail below, or the trialkylaluminum and the solvent are distilled off. It may be used as a dry-modified methylaluminoxane.

Examples of the boron compound include arylboron compounds such as trispentafluorophenylboran. Further, as the boron compound, a boron compound having an anionic species can be used. For example, aryl borates such as tetrakispentafluorophenyl borate and tetrakis (3,5-trifluoromethylphenyl) borate can be mentioned. Specific examples of arylborates include lithium tetrakispentafluorophenylborate, sodium tetrakispentafluorophenylborate, N, N-dimethylanilinium tetrakispentafluorophenylborate, trityltetrakispentafluorophenylborate, and lithium tetrakis (3,5-tri). Fluoromethylphenyl) borate, sodium tetrakis (3,5-trifluoromethylphenyl) borate, N, N-dimethylanilinium tetrakis (3,5-trifluoromethylphenyl) borate, trityltetrakis (3,5-trifluoromethyl) Phenyl) Borate and the like. Among these, N, N-dimethylanilinium tetrakispentafluorophenylborate, trityltetrakispentafluorophenylborate, N, N-dimethylanilinium tetrakis (3,5-trifluoromethylphenyl) borate or trityltetrakis (3,5) -Trifluoromethylphenyl) borate is preferred. These boron compounds may be used alone or in combination of two or more.

<(D) Organozinc compound, Organoaluminium compound>
The catalyst according to this embodiment contains (D) an organozinc compound and / or an organoaluminum compound other than methylaluminoxane.

Specific examples of the organozinc compound include alkylzinc such as dimethylzinc and diethylzinc, and arylzinc such as diphenylzinc. Further, the organic zinc compound is formed in the reaction system by allowing zinc halide such as zinc chloride, zinc bromide and zinc iodide to act with alkyllithium, arylgrineer, alkylgrineer, the following organoaluminum compound and the like. May form an organozinc compound. These organozinc compounds may be used alone or in combination of two or more.

Specific examples of the organic aluminum compound include trimethylaluminum, triethylaluminum, triisopropylaluminum, tripropylaluminum, tributylaluminum, triisobutylaluminum, trihexylaluminum, triphenylaluminum, diethylaluminum chloride, ethylaluminum dichloride, and ethylaluminum sesquichloride. And so on. These organoaluminum compounds may be used alone or in combination of two or more.

Further, when the total number of moles of the contents of (A) and (B) is Y, the content ratio of Y and (C) is the molar ratio when only methylaluminoxane is used as (C). The lower limit of Y / (C—Al) is preferably 1/1000 or more, and more preferably 1/500 or more. On the other hand, the upper limit of Y / (C-A1) is preferably 1/10 or less, and more preferably 1/20 or less. When the total amount of (A) and (B) and the content ratio of (C-Al) are within the above range, it is possible to suppress the factor of cost increase while exhibiting more sufficient polymerization activity. In addition, (C-Al) represents the number of moles of aluminum atoms in methylaluminoxane.

On the other hand, when only the boron compound is used as (C), the lower limit of Y / (CB) in terms of molar ratio is preferably 1/10 or more, and more preferably 1/2 or more. On the other hand, the upper limit of Y / (CB) is preferably 10/1 or less, and more preferably 2/1 or less. When the total amount of (A) and (B) and the content ratio of (CB) are within the above range, it is possible to suppress the factor of cost increase while exhibiting more sufficient polymerization activity. In addition, (CB) represents the number of moles of a boron compound. When only a boron compound is used as (C), it is particularly preferable to use an alkyl complex for (A) and (B) or to add an operation of converting to an alkyl complex. Examples of the method for converting to an alkyl complex include organic aluminum compounds such as trimethylaluminum, organic zinc compounds such as dimethylzinc, organic lithium compounds such as methyllithium, and methylmagnesium chloride, for example, in the case of conversion to a methyl complex. By contacting (A) or (B) with a Grineer compound or the like, conversion into a methyl complex of (A) or (B) can be mentioned. As the organoaluminum compound and the organozinc compound mentioned here, those described in (D) above can be used.

When methylaluminoxane and a boron compound are used in combination as (C), Y / (C—Al) is 1/100 or more and Y / (CB) is 1/10 or more in terms of molar ratio. It is preferable that Y / (C—Al) is 1/50 or more and Y / (CB) is 1/2 or more. Further, the upper limit of the molar ratio is preferably Y / (C—Al) of 1/1 or less and Y / (CB) of 1/1 or less. If the total amount of (A) and (B) and the content ratio of (C-Al) and the total amount of (A) and (B) and the content ratio of (CB) are within the above ranges, It is possible to suppress factors of cost increase while exhibiting more sufficient polymerization activity. Furthermore, the conversion of the above-mentioned (A) and (B) to the alkyl complex can be performed at the same time.

Further, regarding the content ratios of Y and (D), the lower limit of Y / (D) in terms of molar ratio is preferably 1/1000 or more, and more preferably 1/800 or more. On the other hand, the upper limit of Y / (D) is preferably 1 or less, and more preferably 1/10 or less. When the total amount of (A) and (B) and the content ratio of (D) are within the above range, the effect of the chain recombination polymerization by the complexes (A) and (B) is remarkably exhibited, and the reaction efficiency is further improved. It is possible to effectively improve and produce an oligomer having a more appropriate molecular weight. The content ratio of (D) represents the number of moles of aluminum atoms in the organoaluminum compound when the organoaluminum compound is used as (D).

[Oligomer production method]
The production method according to the present embodiment includes a step of oligomerizing ethylene in the presence of the above catalyst.

In the method for producing an oligomer in the present embodiment, the reaction solvent is preferably a non-polar solvent from the viewpoint of satisfactorily carrying out the polymerization reaction. Examples of the non-polar solvent include normal hexane, isohexane, heptane, octane, isooctane, cyclohexane, methylcyclohexane, benzene, toluene, xylene and the like.

The reaction temperature in this embodiment is not particularly limited, but for example, the lower limit is preferably 0 ° C. or higher, more preferably 10 ° C. or higher, and even more preferably 20 ° C. or higher. On the other hand, the upper limit of the reaction temperature is, for example, preferably 100 ° C. or lower, more preferably 90 ° C. or lower, and further preferably 80 ° C. or lower. When the reaction temperature is 0 ° C. or higher, the reaction can be efficiently carried out without requiring a large amount of energy for cooling, and when the reaction temperature is 100 ° C. or lower, the decrease in activity of the iron compound (B) can be suppressed. .. The reaction pressure is also not particularly limited, but for example, the lower limit is preferably 100 kPa or more, and the upper limit is preferably 5 MPa or less. The reaction time is also not particularly limited, but for example, the lower limit is preferably 1 minute or more, and the upper limit is preferably 24 hours or less.

Since the oligomer obtained by the above-mentioned production method in the present embodiment is more colorless and transparent, it can be suitably used as a component of, for example, a lubricating oil composition.

The lower limit of the number average molecular weight (Mn) of the oligomer obtained by the above-mentioned production method in the present embodiment is, for example, 200 or more, preferably 300 or more. The upper limit of Mn is, for example, 5000 or less, preferably 4000 or less. The number average molecular weight (Mn) of the oligomer can be determined as a polystyrene-equivalent amount based on a calibration curve prepared from standard polystyrene, for example, using a GPC apparatus.

Hereinafter, the present invention will be illustrated in Examples, but the following Examples are not intended to limit the present invention.

<Catalyst production and oligomer production>
[Preparation of materials]
As the rac-ethylidenebis indenyl zirconium chloride, the one purchased from Wako Pure Chemical Industries, Ltd. was used as it was. The iron compound was synthesized by the method shown in the synthesis example described later. As the reagents used at that time, the purchased products were used as they were. Trimethylaluminum made of Nippon Aluminum Alkyls was diluted with dry toluene and used. For diethylzinc, a toluene solution manufactured by Tokyo Kasei was used as it was. As the methylaluminoxane, TMAO-341 manufactured by Tosoh Finechem was used as it was. As the trityl tetrakispentafluorophenyl borate, the one manufactured by Tokyo Kasei was used as it was.
As ethylene, high-purity liquefied ethylene manufactured by Sumitomo Seika Chemical Co., Ltd. was used, and it was dried and used through Molecular Sieve 4A.
As the solvent toluene, dehydrated toluene manufactured by Aldrich was used as it was.

[Measurement of number average molecular weight (Mn)]
Two columns (manufactured by Polymer Laboratories, trade name: PL gel 10 μm MIXED-B LS) were connected to a high-temperature GPC apparatus (manufactured by Polymer Laboratories, trade name: PL-20) to obtain a differential refractive index detector. 5 ml of orthodichlorobenzene solvent was added to 5 mg of the sample, and the mixture was heated and stirred at 140 ° C. for about 1 hour. The sample thus dissolved was measured at a flow rate of 1 ml / min and the temperature of the column oven was set to 140 ° C. The molecular weight was converted based on a calibration curve prepared from standard polystyrene, and the polystyrene-equivalent molecular weight was determined.

[Calculation of catalyst efficiency]
The catalyst efficiency was calculated by dividing the weight of the obtained oligomer by the total number of moles of the charged catalyst.

[Synthesis of diimine compounds]
2-Methyl-4-methoxyaniline (2.0893 g, 15.3 mmol) (manufactured by Tokyo Kasei) and 2,6-diacetylpyridine (1.2429 g, 7.6 mmol) (manufactured by Tokyo Kasei), Molecular Sieve 4A (5. 0 g), a catalytic amount of paratoluenesulfonic acid was dispersed in dry toluene (60 ml), and the mixture was stirred with heating and refluxing for 24 hours while removing water using a Dean-Stark water separator.

The molecular sieve was removed from the reaction solution by filtration, and the molecular sieve was washed with toluene. The washing liquid and the filtered reaction liquid were mixed and concentrated to dryness to obtain a crude solid (2.8241 g). The crude solid (2 g) obtained here was weighed and washed with absolute ethanol (30 ml). The ethanol-insoluble solid was filtered off and the insoluble solid was further washed with ethanol. The residual solid was sufficiently dried to obtain the following diimine compound in a yield of 50%.

^{1 1} H-NMR (600MHz, CDCl ₃ ): 2.1 (s, 6H), 2.4 (s, 6H), 3.8 (s, 6H), 6.6 (m, 2H), 6.7 (M, 2H), 6.8 (m, 2H), 7.9 (m, 1H), 8.4 (m, 2H)
¹³ C-NMR (600 MHz, CDCl ₃ ): 16, 18, 56, 116, 119, 122, 125, 129, 137, 138, 143, 156, 167

[Synthesis of iron compounds]
_{FeCl 2 · 4H 2 O (0.2401g} , 1.2mmol) and (Kanto Chemical) was dissolved in dehydrated tetrahydrofuran (30 ml) (manufactured by Aldrich), diimine compound synthesized in the previous (0.4843G, 1.2 mmol) Tetrahydrofuran solution (10 ml) was added. The addition of the yellow diimine compound instantly resulted in a dark green tetrahydrofuran solution. Further, the mixture was stirred at room temperature for 2 hours. The solvent was evaporated to dryness from the reaction solution, and the precipitated solid was washed with dehydrated ethanol until the filtrate lost its color. Further, the washed solid was washed with dehydrated diethyl ether, and the solvent was removed to obtain an iron complex. The obtained iron compound obtained 527.0820 (calculated value: 527.0831) by FD-MASS, suggesting the following structure.

<Example 1>
The iron compound obtained above was added to dehydrated toluene to prepare a solution (A) having an iron compound concentration of 2 mM. Similarly, rac-ethylideneindenyl zirconium dichloride was added to dehydrated toluene to prepare a solution (B) at a concentration of 2 mM. Put 20 ml of dehydrated toluene in a 50 ml eggplant flask, then add 0.5 ml of solution (A) and 0.5 ml of solution (B), and further add TMAO-341 (3.46 M hexane solution, 0.03 ml, mol of zirconium and iron). Taking the total number as "metal", Al / metal = 50) was added, and then trimethylaluminum (2M toluene solution, 0.05 ml, Al / metal = 50) was added to prepare a catalyst.

The catalyst prepared above was added to an autoclave into which dried toluene (80 ml) was introduced, and 0.19 MPa of ethylene was continuously introduced at room temperature (25 ° C.). After 30 minutes, the introduction of ethylene was stopped, unreacted ethylene was removed, ethylene in the autoclave was purged with nitrogen, and a very small amount of ethanol was added. The autoclave was opened, the contents were transferred to a 200 ml eggplant flask, and the solvent was distilled off under reduced pressure to obtain a semi-solid oligomer. The catalyst efficiency (CE) was 3343 kg / metal mol. The Mn of the obtained oligomer was 320.

<Example 2>
The same operation as in Example 1 was carried out except that the ethylene introduction time was set to 60 minutes. The catalyst efficiency (CE) was 4645 kg / metal mol. The Mn of the obtained oligomer was 310.

<Example 3>
Trityl tetrakispentafluorophenylborate (boron compound) was dissolved in dehydrated toluene to prepare a solution (C) having a concentration of the boron compound of 2 mM. Put 20 ml of dehydrated toluene in a 50 ml eggplant flask, then add 0.5 ml of solution (A) and 0.5 ml of solution (B), and then add solution (C) (1 ml, boron / metal = 1/1). , Trimethylaluminum (2M toluene solution, 0.05 ml, Al / metal = 50) was added to prepare a catalyst.

The catalyst prepared above was added to an autoclave into which dried toluene (80 ml) was introduced, and 0.19 MPa of ethylene was continuously introduced at 10 ° C. After 60 minutes, the introduction of ethylene was stopped, unreacted ethylene was removed, ethylene in the autoclave was purged with nitrogen, and a very small amount of ethanol was added. The autoclave was opened, the contents were transferred to a 200 ml eggplant flask, and the solvent was distilled off under reduced pressure to obtain a semi-solid oligomer. The catalyst efficiency (CE) was 5148 kg / metal mol. The Mn of the obtained oligomer was 340.

<Comparative example 1>
20 ml of dehydrated toluene was placed in a 50 ml eggplant flask, then 0.5 ml of solution (A) was added, and then trimethylaluminum (2M toluene solution, 0.05 ml, Al / Fe = 500) was added to prepare a catalyst.

The catalyst prepared above was added to an autoclave into which dried toluene (80 ml) was introduced, and 0.19 MPa of ethylene was continuously introduced at room temperature (25 ° C.). After 30 minutes, the introduction of ethylene was stopped, unreacted ethylene was removed, ethylene in the autoclave was purged with nitrogen, and a very small amount of ethanol was added. The autoclave was opened, the contents were transferred to a 200 ml eggplant flask, and the solvent was distilled off under reduced pressure to obtain a semi-solid oligomer. The catalyst efficiency (CE) was 1395 kg / Fe mol. The Mn of the obtained oligomer was 370.

Claims (5)

(A) A rac-ethylidene indenyl zirconium compound represented by the following general formula (1),
(B) An iron compound represented by the following general formula (2),
(C) Methylaluminoxane and / or boron compounds, and
(D) Organozinc compounds and / or organoaluminum compounds other than methylaluminoxane,
A method for producing an oligomer, which comprises a step of oligomerizing ethylene in the presence of a catalyst containing the above.

[In the formula (1), X represents a halogen atom, a hydrogen atom or a hydrocarbyl group having 1 to 6 carbon atoms. ]

[In formula (2), R represents a hydrocarbyl group having 1 to 6 carbon atoms or an aromatic group having 6 to 12 carbon atoms, and a plurality of Rs in the same molecule may be the same or different, and R'is oxygen. It represents a free radical having 0 to 6 carbon atoms with an atom and / or a nitrogen atom, and a plurality of R'in the same molecule may be the same or different, and Y represents a chlorine atom or a bromine atom. ] The production method according to claim 1, wherein the number average molecular weight (Mn) of the oligomer is 200 to 5000. The group consisting of trimethylaluminum, triethylaluminum, triisopropylaluminum, tripropylaluminum, tributylaluminum, triisobutylaluminum, trihexylaluminum, triphenylaluminum, diethylaluminum chloride, ethylaluminum dichloride and ethylaluminum sesquichloride. The production method according to claim 1 or 2, which is at least one selected from the above. The production method according to any one of claims 1 to 3, wherein the organozinc compound is at least one selected from the group consisting of dimethylzinc, diethylzinc and diphenylzinc. The boron compounds are trispentafluorophenylborane, lithium tetrakispentafluorophenylborate, sodium tetrakispentafluorophenylborate, N, N-dimethylanilinium tetrakispentafluorophenylborate, trityltetrakispentafluorophenylborate, and lithium tetrakis (3,). At least one selected from the group consisting of 5-trifluoromethylphenyl) borate, N, N-dimethylanilinium tetrakis (3,5-trifluoromethylphenyl) borate and trityltetrakis (3,5-trifluoromethylphenyl) borate. The production method according to any one of claims 1 to 4, which is a species.