JP3385653B2 - Low polymerization method of α-olefin - Google Patents

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for low polymerization of α-olefins. More specifically, the present invention relates to a low polymerization method of α-olefins which can selectively obtain a product mainly containing trimers from ethylene in high yield using a chromium-based catalyst.

[0002]

2. Description of the Related Art Conventionally, it has been known that an α-olefin such as ethylene is low-polymerized by using a catalyst composed of a combination of a specific chromium compound and a specific organic aluminum compound. For example, Japanese Patent Publication No. 43-18707 discloses a method for obtaining 1-hexene and polyethylene from ethylene by a catalyst system comprising a transition metal compound of Group VIA containing Cr represented by the general formula MXn and polyhydrocarbyl aluminum oxide. Further, in Japanese Patent Laid-Open No. 128904/1993, α-olefins are treated with a catalyst obtained by previously reacting a chromium-containing compound having a chromium-pyrrolyl bond with a metal alkyl or Lewis acid. A quantification method is described.

On the other hand, the present inventors previously set out a method for carrying out a low polymerization reaction of an α-olefin by defining a contact method of a chromium-containing compound having a chromium-pyrrolyl bond, an α-olefin, and an alkylaluminum. Proposed. According to this method, 1-hexene can be obtained with a surprisingly high activity, especially by a low polymerization reaction of ethylene. Furthermore, the present inventors have produced a chromium-containing compound having a chromium-pyrrolyl bond in a high yield without a complicated operation by using a hydrocarbon as a solvent, and by using it in combination with an alkylaluminum compound, We have also proposed a method that can produce highly pure 1-hexene by performing a low polymerization reaction of α-olefin, particularly a trimerization reaction of ethylene with high activity.

Recently, the present inventors have conducted a low polymerization reaction of α-olefins, particularly a trimerization reaction of ethylene, by defining a contact method of a chromium salt, an amine, an α-olefin, and an alkylaluminum compound. I also proposed a method.

[0005]

However, in the method described in Japanese Patent Publication No. 43-18707, the amount of polyethylene produced at the same time as 1-hexene is large, and when the amount of polyethylene is reduced, the total activity is reduced. However, on the other hand, there is a problem in that
The method described in Japanese Patent Laid-Open Publication No. 2003-242242 produces a small amount of high molecular weight polymer, but has a problem that the catalytic activity is not sufficient.

The present invention solves the problems of the above-mentioned conventional methods, has a high yield, a high selectivity and is industrially advantageous in α-.
It is an object of the present invention to provide a novel method for low polymerization of α-olefin, which makes it possible to obtain a low polymerization product of olefin, particularly 1-hexene.

[0007]

Means for Solving the Problems As a result of intensive studies aimed at achieving such an object, the present inventors have found that α-olefins, especially ethylene, can be obtained by using a chromium catalyst composed of a chromium salt, an amine and an alkylaluminum compound. In the method of low polymerization of, using an aliphatic hydrocarbon as a solvent,
By carrying out a low polymerization reaction using an aromatic hydrocarbon compound having 2 or less aliphatic hydrocarbon substituents in an amount within the range of 40% or less of the charged solution amount, 1- The inventors have found that hexene is produced, and completed the present invention.

That is, the gist of the present invention is to use an aliphatic hydrocarbon as a solvent in a method for low-polymerizing an α-olefin by using a chromium catalyst composed of a chromium salt, an amine, and an alkylaluminum compound, and use 2 or less. A method for low polymerization of α-olefin, characterized in that the low polymerization reaction is carried out by using an aromatic hydrocarbon compound having an aliphatic hydrocarbon substituent in an amount within the range of 0.1 ppm or more and 40% or less of the amount of the charged solution. Exist in.

The present invention will be described in more detail below.

The chromium salt used in the present invention is
General formula CrXn (wherein the valence of chromium is 1 to 6)
Yes, X is the same or different from each other
It is a machine base, and n is an integer of 1 to 6. )
Be done. The number of n is preferably 2 or more. As an organic group
Is a hydrocarbon group, carbonyl group, alkoxy group, carbo
Xyl group, β-diketonate group, β-keto ester group and
And amide groups and the like. The carbon number of the organic group is usually 1
To 30 and the hydrocarbon group is an alkyl group, cyclo
Alkyl group, aryl group, alkylaryl group, aral
A kill group etc. are mentioned. As inorganic groups, halogen, glass
An acid group, a sulfuric acid group, oxygen, etc. are mentioned. Preferably
Is chromium salt, alkoxy salt, carboxyl salt, β-di
Ketonate salt, salt with β-ketoester anion,
Rui is a halide, specifically chromium (IV) tert.
-Butoxide, chromium (III) acetylacetonate, chloro
(III) trifluoroacetylacetonate, chromium (II
I) Hexafluoroacetylacetonate, chromium (II
I) (2,2,6,6-tetramethyl-3,5-heptanedi
Onato), Cr (PhCOCHCOPh)₃(However, here
And Ph represents a phenyl group. ), Chrome (II) asset
Chromium (III) acetate, chromium (III) 2-ethyl
Xanoate, Chromium (III) Benzoate, Chromium (III)
Naphthenate, Cr (CH₃COCHCOOCH₃)₃,salt
Chromium Chromide, Chromium Chloride, Chromium Chromide, Bromide
Chromium chrome, Chromium iodide, Chromium iodide, F
Chromium nitride, chromic fluoride, etc. may be mentioned. Well
Also, a complex consisting of these chromium salts and an electron donor is also used.
You can As electron donors, nitrogen, oxygen,
And sulfur compounds. Nitrogen-containing compound
Examples of the product include nitrile, amine, amide, and the like,
Specifically, acetonitrile, pyridine, dimethyl pyri
Gin, dimethylformamide, N-methylformami
De, aniline, nitrobenzene, tetramethylethylene
Diamine, diethylamine, isopropylamine, hex
Examples include samethyldisilazane and pyrrolidone. oxygen
Examples of contained compounds include esters, ethers, ketones, and
Examples include alcohol and aldehyde.
Luacetate, methyl acetate, tetrahydrofura
Amine, dioxane, diethyl ether, dimethoxyethane
, Diglyme, triglyme, acetone, methyl ethyl
Luketone, methanol, ethanol, acetaldehyde
Etc. As a phosphorus compound,
Osformamide, hexamethylphosphoria
Mid, triethylphosphite, tributylphosphite
Examples include tin oxide and triethylphosphine.
It Sulfur-containing compounds include carbon disulfide and dimethyl
Rufoxide, tetramethylene sulfone, thiophe
And dimethyl sulfide. Therefore, black
Examples of complexes consisting of ammonium salts and electron donors include halogenated compounds.
Chromium ether complex, ester complex, ketone complex,
Ludehyde complex, alcohol complex, amine complex, phosphine
And a thioether complex.
Is CrCl₃・ 3THF, CrCl₃・ 3dioxan
e, CrCl₃・ (CH₃CO₂n-C_FourH₉), CrCl₃
・ (CH₃CO₂C₂H_Five), CrCl₃・ 3 (i-C₃H₇O
H), CrCl₃・ 3 [CH₃(CH₂)₃CH (C₂H_Five)
CH₂OH], CrCl₃・ 3pyridine, CrC
l₃・ 2 (i-C₃H₇NH₂), [CrCl₃・ 3CH₃C
N] ・ CH₃CN, CrCl₃・ 3PPh₃, CrCl₂・
2THF, CrCl₂・ 2pyridine, CrCl₂
・ 2 [(C₂H_Five)₂NH], CrCl₂・ 2CH₃CN, C
rCl₂・ 2 [P (CH₃) ₂Ph] and the like. Ku
As the ROM salt, a compound soluble in a hydrocarbon solvent is more preferable.
Preference is given to chromium β-diketonate salts and chromium carbohydrates.
Phosphate, a salt of chromium β-ketoester anion,
Β-ketocarboxylate of chromium, amide complex of chromium,
Chromium carbonyl complexes, chromium cyclopentadiene
Examples include enyl complex, alkyl complex, phenyl complex, etc.
It Various cyclopentadienyl complexes of chromium, alkyl
As the complex, phenyl complex, etc., CpCrCl₂(here
Cp represents a cyclopentadienyl group. ), (Cp * C
rClCH₃)₂(Where Cp * is pentamethylcyclopen
Indicates a tadienyl group. ), (CH₃)₂Examples include CrCl
To be done.

Further, instead of the chromium salt and amine as the chromium catalyst of the present invention, for example, a chromium-containing compound having a chromium-pyrrolyl bond can be used. The chromium-containing compound having a chromium-pyrrolyl bond can be obtained by reacting the above-illustrated chromium salt and metal pyrrolide in a solvent. Metal pyrrolides refer to those derived from pyrrole and derivatives of pyrrole, and as pyrrole derivatives, 2,5-dimethylpyrrole, 3,4-
Dimethylpyrrole, 3,4-dichloropyrrole, 2,
3,4,5-tetrachloropyrrole, 2-acylpyrrole and the like can be mentioned. Examples of the metal include IA group, IIA group and II
It is selected from Group IB and Group IVB. Examples of preferable metal pyrrolides include lithium pyrrolide, sodium pyrrolide, potassium pyrrolide, and cesium pyrrolide. Further, pyrrole and the pyrrole derivative itself may be used instead of the metal pyrrolide.

Further, in the present invention, by using a chromium salt and an amine as a chromium catalyst, it is not necessary to once synthesize and isolate a chromium-containing compound having a chromium-pyrrolyl bond which is extremely unstable to air or humidity. .
Therefore, it is not necessary to go through the production process and isolation process of the chromium-containing compound in addition to the low polymerization process of α-olefin,
Further, there is an advantage that an unstable storage tank for the compound is unnecessary and the construction cost for the whole manufacturing process is reduced.

In the present invention, a chromium salt or a chromium-containing compound containing a chromium-pyrrolyl bond may be used by supporting it on a carrier such as an inorganic oxide, but preferably, such an operation is simply carried out and an alkyl is simply used. It may be used only in combination with an aluminum compound and / or an amine. Low polymerization of α-olefin in the present invention,
Normally, it is carried out in a hydrocarbon solvent, but the concentration of chromium salt and chromium-containing compound is 0.1 per liter of solvent.
mg to 5 g, preferably 1 mg to 2 g.

The amine, another component of the catalyst system of the present invention, is a primary or secondary amine, a metal amide derived from a primary or secondary amine, and mixtures thereof collectively referred to as amine. Will be called. Examples of the primary amine include ammonia, ethylamine, isopropylamine, cyclohexylamine, benzylamine, aniline, naphthylamine, and the like, and secondary amines include diethylamine, diisopropylamine, dicyclohexylamine, dibenzylamine, bis (trimethylsilyl) amine. , Morpholine, imidazole, indoline, indole, pyrrole, 2,5-dimethylpyrrole, 3,4-dimethylpyrrole, 3,4-dichloropyrrole, 2,3,4,5-tetrachloropyrrole, 2-acylpyrrole, pyrazole , Pyrrolidine, etc. are exemplified. 1
Examples of the metal amide derived from a primary or secondary amine include the primary or secondary amine and the group IA, II exemplified above.
Amides obtained by reaction with a metal selected from Group A, Group IIIB, and Group IVB, such as lithium amide, sodium ethylamide, calcium bis (ethylamide), lithium diisopropylamide, potassium benzylamide, sodium bis ( Examples include trimethylsilyl) amide, lithium indolide, sodium pyrrolide, lithium pyrrolide, potassium pyrrolide, potassium pyrrolidide, aluminum diethylpyrrolide, ethylaluminum dipyrrolide, and aluminum tripyrolide. As the amine, a secondary amine, an amide derived from a secondary amine, and a mixture thereof are preferable, and specifically, pyrrole,
2,5-dimethylpyrrole, 3,4-dimethylpyrrole,
3,4-dichloropyrrole, 2,3,4,5-tetrachloropyrrole, 2-acylpyrrole, and aluminum pyrrolide, ethylaluminum dipyrrolide, aluminum tripyrolide, sodium pyrrolide, lithium pyrrolide, potassium pyrrolide Ride etc. are mentioned.

The amount of amine used is not less than 0.001 equivalent with respect to the chromium salt, and the upper limit is not particularly limited, but it is not necessary to use an unnecessarily large amount of amine. The amount of the amine used is preferably 0.005 equivalents to 1000 equivalents, more preferably 0.01 equivalents to 100 equivalents, relative to the chromium salt.

In the present invention, the low polymerization reaction of α-olefin is carried out by combining the above chromium salt, amine and alkylaluminum compound. As the alkylaluminum compound, the following general formula R ¹ _m Al (OR ² ) _n H _p X _q ... (1) (In the formula, R ¹ and R ² have a carbon number of usually 1 to 15, preferably 1 ~ 8 hydrocarbon groups, which may be the same or different from each other, X represents a halogen atom, m is 0 <m≤3, n is 0≤n <3, and p is 0≤p <. 3, q is 0
≦ q <3, and m + n + p +
Represents a number where q = 3. Alkyl aluminum compounds are preferred which are represented by) _{^{e.g., R 1 3 Al ··· (2}} ) ( wherein, R ¹ is trialkylaluminum compound represented by the same) and _{^{the, R 1 m AlX 3-m}} ·· (3) (In the formula, R ¹ and X are the same as above. M is 1.5 ≦ m <3
Is. R ¹ _m Al (OR ² ) _3-m ... (4) (wherein R ¹ and R ² are the same as above. M is 0 <m <3, preferably Is an alkoxyaluminum compound represented by 1.5 ≦ m <3, R ¹ _m AlH _{3 −m} (5) (wherein R ¹ is the same as above. M is 0 <m <3. , Preferably 1.5 ≦ m <3). Specific examples thereof include trimethyl aluminum, triethyl aluminum, triisobutyl aluminum, diethyl aluminum monochloride, diethyl aluminum ethoxide, diethyl aluminum hydride, and the like. More preferable.

The amount of alkylaluminum compound used is
0.1 mmol / g of chromium salt or more, but 5 mmol
/ Chromium salt g is preferable in terms of activity and improvement in trimer selectivity. 2 used in the present invention
As the aliphatic hydrocarbon substituent in the aromatic hydrocarbon compound having not more than 4 aliphatic hydrocarbon substituents, a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a cyclopropyl group, a cyclobutyl group, a cyclohexyl group. Examples thereof include linear or alicyclic hydrocarbon groups.
Specific examples of the hydrocarbon-substituted aromatic hydrocarbon compound used include benzene, toluene, ethylbenzene, o-
Xylene, m-xylene, p-xylene, cumene, p-cymene, 1,4-dibutylbenzene, tert-butylbenzene, 1,4-di-tert-butylbenzene, cyclohexylbenzene, 1,4-dicyclohexylbenzene,
Methylnaphthalene, 2,6-dimethylnaphthalene, 1,
Examples thereof include 5-dimethylnaphthalene.

The addition amount of the aromatic hydrocarbon compound having two or less aliphatic hydrocarbon substituents is preferably 0.1 ppm or more, preferably 10 ppm or more, and more preferably 0.1% or more of the amount of the charged solution. Yes, the upper limit is
The range is 40% or less, preferably 30% or less, and more preferably 20% or less.

In the present invention, when a low-polymerization reaction of α-olefin, particularly ethylene, is carried out with an aromatic hydrocarbon compound having two or less aliphatic hydrocarbon substituents as an additive, the purity of α-olefin produced Is improved. The reason for this is not yet speculated, but a hydrocarbon-substituted aromatic hydrocarbon compound is included in hexenes by coordinating with a chromium catalyst prepared from a chromium salt, an amine, and an alkylaluminum compound. It is considered that the purity of 1-hexene is improved because the formation of the positional isomer of the heavy bond is suppressed. Further, the aromatic hydrocarbon compound having an aliphatic hydrocarbon substituent used in the present invention is
It may be added to the reaction system by any method.

In the present invention, these chromium salts, amines,
And the chromium catalyst consisting of alkylaluminum compound becomes an active species to cause low polymerization of α-olefins.
It is preferred to feed the α-olefin and the chromium catalyst to the reaction system without prior contact of the chromium salt with the alkylaluminum compound. For that purpose, the most reliable method is to prevent the chromium salt and the alkylaluminum compound from physically contacting each other in advance. Specifically, in a solution containing (1) an amine and an alkylaluminum compound, α- (2) Introducing the olefin and the chromium salt into the solution containing the chromium salt and the amine, α
-(3) introducing an olefin and an alkylaluminum compound into a solution containing a chromium salt, introducing an α-olefin, an amine and an alkylaluminum compound into the solution containing (4) an alkylaluminum compound, including an α-olefin, Examples include a method of introducing a chromium salt and an amine, and (5) a method of simultaneously and independently introducing a chromium salt, an amine, an alkylaluminum compound and an α-olefin into a reaction system.

When the chromium salt is reacted with the alkylaluminum compound in advance, α-
The low polymerization reaction activity of olefin becomes low. The reason for this is not clear yet, but when a chromium salt is reacted with an alkylaluminum, a ligand coordinated with the chromium salt,
It is considered that the ligand exchange reaction proceeds with the alkyl group in the alkylaluminum compound, but the alkyl-chromium compound formed at this time is unstable by itself, and the decomposition-reduction reaction of the alkyl-chromium compound is It is considered that the progress proceeds preferentially, and as a result, demetallation unsuitable for the low polymerization reaction occurs, so that the low polymerization reaction activity of the α-olefin decreases.

The reaction temperature in the present invention is 0 to 250 ° C, preferably 0 to 150 ° C. The reaction pressure may be atmospheric pressure or 250 kg / cm ² , but 100 kg /
cm ² or less is sufficient. In the present invention, low polymerization reaction is carried out using an aliphatic hydrocarbon solvent, butane, pentane, hexane, heptane, octane, cyclohexane, methylcyclohexane, linear or alicyclic saturated hydrocarbon such as decalin, A chain or cyclic unsaturated hydrocarbon compound such as 5-decene, 6-dodecene, cyclohexene or cyclooctene is used. Of these solvents,
Straight-chain or alicyclic saturated hydrocarbons are preferred. Also,
The α-olefin itself of the reaction raw material or the α-olefin other than the main raw material of the reaction can be used as a solvent. As these α-olefins, those having 4 to 30 carbon atoms are used, but those which are liquid at room temperature are particularly preferable. Further, a mixture of the compounds exemplified here may be used as a reaction solvent.

The starting α-olefin used in the present invention is a substituted or unsubstituted 2 to 30 carbon atom. Specific examples include ethylene, propylene,
1-butene, 1-hexene, 1-octene, 3-methyl-1-
Butene, 4-methyl-1-pentene and the like can be mentioned. The present invention is particularly suitable for low polymerization of ethylene, and 1-hexene can be obtained with high activity and high selectivity.

Although the reaction can be carried out batchwise, the method of the present invention is also effective when carrying out the reaction in a continuous system in which a higher purity of the product is required than an improvement in activity. The residence time is in the range of 1 minute to 20 hours, preferably 0.
5 to 6 hours. In the low polymerization of the α-olefin of the present invention, hydrogen can coexist during the reaction. The coexistence of hydrogen is preferable because the activity and the trimer selectivity are improved.

[0025]

EXAMPLES The present invention will be described in more detail below with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples unless it exceeds the gist.

Example 1 A 300 ml autoclave that had been heated and dried in a dryer at 150 ° C. was assembled while hot, and vacuum nitrogen substitution was performed. A catalyst feed tube equipped with a rupture plate was attached to this autoclave. Heptane (47 ml), triethylaluminum heptane solution (0.4 mmol, 1 ml), pyrrole heptane solution (1.3 ml, 0.0625 mmo)
1) and benzene (1 ml, 9.41 mmol) were charged to the autoclave barrel side while the catalyst feed tube was charged with chromium (III) 2-ethylhexanoate (10 mg,
A solution of 0.0208 mmol) in heptane (1 ml) was charged. At this point, the chromium salt and triethylaluminum are not in contact. The autoclave was heated to 100 ° C, and then ethylene was introduced at 100 ° C through a catalyst feed tube. The rupture plate ruptured due to ethylene pressure, the chromium salt was introduced into the autoclave barrel side, and low polymerization of ethylene started. Total pressure of ethylene was introduced until 35 kg / cm ^2, thereafter, the total pressure 35 kg / cm ^2, the reaction temperature 10
Maintained at 0 ° C. After 1 hour, the reaction was stopped by injecting ethanol and the product was quantified by gas chromatography. The results are shown in Table-2.

Example 2 A reaction was carried out in the same manner as in Example 1 except that benzene was toluene (1 ml, 9.41 mmol). Example 3 Toluene was not put in the autoclave barrel side, and chromium (III) 2-ethylhexanoate (10 mg, 0.02) was used.
The reaction was performed in the same manner as in Example 2 except that a toluene (1 ml, 9.41 mmol) solution was used instead of the 08 mmol) heptane solution.

Example 4 A reaction was carried out in the same manner as in Example 2 except that the amount of triethylaluminum used was 0.8 mmol. Example 5 Chromium (III) acetylacetonate (10 m) was used instead of chromium (III) 2-ethylhexanoate.
g, 0.028 mmol), the addition amount of pyrrole was 0.085 mmol, and the use amount of triethylaluminum was 0.57 mmol, and the reaction was performed in the same manner as in Example 2.

Example 6 Benzen was treated with m-xylene (1.15 ml, 9.41 mm).
reaction was performed in the same manner as in Example 1 except that Example 7 The amount of chromium salt used was 5 mg, the amount of pyrrole was 2,5-dimethylpyrrole (3 mg, 0.0312 mmol), and the amount of triethylaluminum was 0.2 mmol.
And the reaction was performed in the same manner as in Example 2 except that the reaction temperature was 90 ° C.

Example 8 Toluene was added in an amount of 5 ml, and pyrrole was 2,5-dimethylpyrrole (5.95 mg, 0.0625 mmol).
And the reaction was performed in the same manner as in Example 2 except that the reaction temperature was 90 ° C. Chromium catalyst production example (production of Cr compound-1) NaH 0.79 g (16.5 mmol) in THF 15 m
1.0 ml of pyrrole dissolved in 5 ml of THF
(15 mmol) was added dropwise. After stirring for 1 hour at room temperature, this solution was suspended in CrCl ₃ in 25 ml of THF.
0.79 g (5 mmol) was added dropwise. After the dropping, the mixture was heated under reflux for 20 hours. After the precipitate was filtered off, the solvent was distilled off to obtain 1.65 g of a black powder. The content of each element in this powder was as follows. Cr: 6.5%, C: 58.0%, H: 6.6%, N:
10.5%.

Example 9 Instead of chromium (III) 2-ethylhexanoate as the chromium compound, the Cr compound-1 obtained in the chromium catalyst preparation example was used.
(10 mg), and the reaction was performed in the same manner as in Example 2 except that pyrrole was not charged on the body side of the autoclave. Example 10 A 300 ml autoclave heated and dried in a dryer at 150 ° C. was assembled while hot, and vacuum nitrogen substitution was performed. A catalyst feed tube equipped with a rupture plate was attached to this autoclave. Heptane (44 ml), toluene (1 ml,
9.41 mmol) and a heptane solution of triethylaluminum (0.4 mmol, 4 ml) were charged into the autoclave barrel side, while the catalyst feed tube was slurried in heptane (1 ml) to obtain the Cr compound obtained in the production example of the chromium catalyst. -1 (10 mg) was charged. Hydrogen is introduced at 3.5 kg / cm ^2, and the autoclave is heated to 100 ° C.
Heated to. Next, ethylene was introduced from the catalyst feed pipe at 100 ° C. The rupture disk bursts due to ethylene pressure,
The ethylene, chromium compound, triethylaluminum, and hydrogen contacted at the same time, and low polymerization of ethylene started.
Introducing ethylene to a total pressure of 40 kg / cm ² , and thereafter
The total pressure was maintained at 40 kg / cm ² and the reaction temperature was maintained at 100 ° C. After 1 hour, the reaction was stopped by injecting ethanol,
The product was quantified by gas chromatography.

Comparative Example 1 The reaction was carried out in the same manner as in Example 1 except that benzene was not added. Comparative Example 2 The reaction was performed in the same manner as in Example 1 except that benzene was not added and pyrrole was 2,5-dimethylpyrrole (0.0625 mmol). Comparative Example 3 The reaction was performed in the same manner as in Example 9 except that toluene was not added.

[0033]

[Table 1]

[0034]

[Table 2]

[0035]

[Table 3]

[0036]

[Table 4]

[0037]

According to the method of the present invention, α-olefin,
In particular, ethylene can be low-polymerized to selectively obtain a trimer-based product, particularly 1-hexene, in a high yield, and suppress the production of a high-molecular weight polymer. In particular, when 1-hexene is industrially produced using the method of the present invention, the purity of 1-hexene is improved, so that the operation for purifying 1-hexene by distillation or the like is facilitated and the cost required for the purification apparatus is reduced. It can be reduced. In addition, since a highly pure product can be obtained without performing a particularly precise refining operation, it has a high industrial utility value.

─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Takayuki Aoshima 1000 Kamoshida-cho, Midori-ku, Yokohama-shi, Kanagawa Mitsubishi Kasei Co., Ltd. (56) Reference JP 62-265237 (JP, A) JP Hei 6-329562 (JP, A) JP-B-48-34721 (JP, B1) (58) Fields investigated (Int.Cl. ⁷ , DB name) C07C 2/30 C07C 2/32 C07C 2/08 C07C 11 / 107 C08F 2/00 C08F 2/06 C08F 4/69 C08F 4/60 C08F 10/00 C10G 50/00 C07B 61/00 300

Claims (4)

(57) [Claims] 1. A method for low-polymerizing an α-olefin using a chromium catalyst composed of a chromium salt, an amine, and an alkylaluminum compound, wherein an aliphatic hydrocarbon is used as a solvent, and two or less aliphatic hydrocarbon substituents are used. Aromatic hydrocarbon compound having a content of 0.1 pp
A low-polymerization method for α-olefins, characterized in that the low-polymerization reaction is carried out using an amount in the range from m to 40%. 2. The low polymerization method of an α-olefin according to claim 1, wherein the α-olefin and a chromium salt are introduced into a solution containing an amine and an alkylaluminum compound. 3. In a solution containing a chromium salt and an amine,
The method for low polymerization of α-olefin according to claim 1, wherein α-olefin and an alkylaluminum compound are introduced. 4. The method for low polymerization of an α-olefin according to claim 1, wherein the α-olefin is ethylene and the main product is 1-hexene.