JPH0920692A - Trimerization of ethylene - Google Patents

Abstract

PROBLEM TO BE SOLVED: To selectively and efficiently obtain highly purified 1-hexene from ethylene by using a catalyst composed of a reaction product of a chromium salt with a metallic amide, an inorganic oxide solid, alumoxane and an electron donor compound. SOLUTION: Ethylene is trimerized by using a catalyst composed of (A) a reaction product of chromium salt (preferably chromous chloride or chromic chloride) with a metallic amide [preferably a bis(trialkyl)amide salt, etc., such as lithium diisopropylamide], (B) an inorganic oxide solid (e.g.; silica), (C) an alumoxane (preferably an alkylalumoxane such as isbutylalumoxane) and (D) an electron donor compound (e.g.; dimethoxymethane). The component A is preferably obtained by reacting a chromium salt with a metallic amide in a ratio of (1:3) of the former to the latter in a solvent such as tetrahydrofuran at -20 deg.C to 40 deg.C for 1-5hrs. Water is preferably removed prior to the use of component B. A trimerizing temperature of ethylene is preferably 0-150 deg.C.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a process for trimerizing ethylene. More specifically, it relates to a method for selectively producing highly pure 1-hexene using a catalyst composed of a reaction product of a chromium salt and a metal amide, an inorganic oxide solid, an alumoxane, and an electron donor compound.

[0002]

2. Description of the Related Art There have already been some proposals for a method for producing 1-hexene by trimerizing ethylene.
For example, Japanese Examined Patent Publication No. 4-66457 describes a method for producing 1-hexene from ethylene with a catalyst comprising chromium (III) tris (2-ethylhexanoate), polyhydrocarbyl aluminum oxide and a donor ligand. There is. However, this method has a problem that the activity of the catalyst is low and a large amount of polyethylene is by-produced. In addition, JP-A-3-115406, 3-12
In 8904, 1 is converted from ethylene by a catalyst composed of a chromium salt, a metal pyrrolide, an electron donor compound, and an inorganic oxide solid.
-A method for producing hexene is described. However, this method has problems that the catalyst preparation operation is complicated, the activity is low, and the purity of 1-hexene with respect to the obtained hexenes is low. In addition, Japanese Patent Laid-Open No. 6-1452
41, 6-157654, 6-157655, 6-26
3822 describes a method for producing 1-hexene from ethylene using a catalyst composed of a chromium compound containing a chromium-pyrrolyl bond and an alkylaluminum. However, this method has a problem that the activity is low and a large amount of polyethylene is by-produced when the catalyst is supported on the inorganic oxide solid in order to facilitate handling of the catalyst and introduction of the catalyst into the reactor.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to propose a method for selectively and efficiently producing highly pure 1-hexene in which the above problems are improved.

[0004]

Means for Solving the Problems As a result of intensive studies in view of the above problems, the present inventors have found that a catalyst composed of a reaction product of a chromium salt and a metal amide, an inorganic oxide solid, an alumoxane and an electron donor compound is used. By using it, a method for producing highly pure 1-hexene selectively and efficiently was found, and the present invention was completed.

Hereinafter, the present invention will be described specifically. Examples of the chromium salt used in the present invention include chromium chloride, chromium chloride, chromium fluoride, chromium fluoride, chromium bromide, chromium bromide, chromium iodide, and iodine. Examples thereof include halides such as chromic chloride, and among them, chromous chloride or chromic chloride is preferable.

The metal amide may be any metal amide obtained by reacting a primary and / or secondary amine or a primary and / or secondary silylamine with an alkali metal and / or an alkaline earth metal. The hydrocarbon portion of the metal amide contains from 2 to 50 carbon atoms and comprises straight or branched chain, cyclic or acyclic, aromatic or aliphatic hydrocarbon groups. Examples include lithium dimethylamide, sodium dimethylamide, lithium diethylamide, sodium diethylamide, lithium diisopropylamide, sodium diisopropylamide, lithium dicyclohexylamide, sodium dicyclohexylamide, lithium diphenylamide, sodium diphenylamide, lithium bis (trimethylsilyl) amide, sodium bis. (Trimethylsilyl) amide, lithium bis (triethylsilyl) amide, sodium bis (triethylsilyl) amide, and the like, and among them, bis (trialkyl) amide salts such as lithium diisopropylamide or bis such as lithium bis (trimethylsilyl) amide. (Trialkylsilyl) amide salts are preferred.

The reaction between the chromium salt and the metal amide is carried out in an ether solvent such as diethyl ether, tetrahydrofuran, dioxane or 1,2-dimethoxyethane. Particularly, tetrahydrofuran or 1,2-dimethoxyethane is preferred. The reaction of chromium salt and metal amide is 1:
It is preferable to carry out at 3. The reaction temperature is -78 ° C to the boiling point of the solvent, preferably -20 ° C to 40 ° C, and the reaction time is 1
It is 0 minutes to 24 hours, preferably 1 to 5 hours. As a result of this reaction, for example, in the case of a reaction between chromium chloride and lithium bis (trimethylsilyl) amide, lithium chloride is deposited, but after removing the precipitated salt by filtration, the ether solvent is removed under vacuum to obtain The obtained solid is dissolved in an inert hydrocarbon such as pentane, hexane, heptane, cyclohexane, benzene, and toluene to give a reaction product.

Examples of the inorganic oxide solid include silica, alumina, silica-alumina, aluminum phosphate and the like. It is desirable to remove the adsorbed moisture from the inorganic oxide solid before use. The inorganic oxide solid is usually dried under a nitrogen gas stream dried under a molecular sieve flow at a temperature in the range of 100 to 900 ° C.
It is performed by arbitrarily selecting from the range of minutes to 10 hours. It is preferable to dry in a solid fluid state with a sufficient amount of nitrogen gas.

Examples of the alumoxane include methyl alumoxane, ethyl alumoxane, isobutyl alumoxane, hexyl alumoxane, chloro alumoxane, etc. Among them, alkyl alumoxane such as isobutyl alumoxane is preferable. These are prepared in a known manner by adding 0.5 to 1.2 of water per equivalent of trialkylaluminum.
It is obtained by reacting water or a water-containing substance with a trialkylaluminum compound in an equivalent ratio. For example, Cam et al. (Makromol. Chem. 191, 1641 (1
990)) obtains an alkylalumoxane by directly introducing water into a cooled toluene solution of trialkylaluminum.

Examples of the electron donor compound include compounds having two or more ether bonds existing through one or more atoms or cyclic ethers. In a compound having two or more ether bonds present through one or more atoms, the atom present between the ether bonds is carbon,
It is one or more selected from the group consisting of silicon, oxygen, nitrogen, sulfur, phosphorus, and boron, and has one or more atoms. Examples of such a compound having two or more ether bonds existing through one or more atoms include compounds represented by the following formulas.

Embedded image (In the formula, n is an integer of 1 ≦ n ≦ 10, and R ^{1 to} R ²⁶ have at least one element selected from carbon, hydrogen, oxygen, halogen, nitrogen, sulfur, phosphorus, boron, and silicon. It is a substituent, and any R ^{1 to} R ²⁶ may together form a ring other than a benzene ring, and the main chain may contain atoms other than carbon.)

Examples of such a compound having two or more ether bonds existing through one or more atoms include, for example, dimethoxymethane, 1,1-dimethoxyethane,
2,2-dimethoxypropane, 1,2-dimethoxyethane, 1,3-dimethoxypropane, diglyme, triglyme, 2,3-dimethoxybutane, 2,3-dimethyl-2,3-dimethoxybutane, 2,2-dimethyl -1,
3-dimethoxypropane, 2,2-diisobutyl-1,
3-dimethoxypropane, 2-isopropyl-2-isopentyl-1,3-dimethoxypropane, 2,2-dicyclohexyl-1,3-dimethoxypropane, 2,2-
Bis (cyclohexylmethyl) -1,3-dimethoxypropane, 2-isopropyl-2-cyclohexyl-1,
3-dimethoxypropane, 2-isopropyl-2-s-
Butyl-1,3-dimethoxypropane, 2,2-diphenyl-1,3-dimethoxypropane, 2-isopropyl-2-cyclopentyl-1,3-dimethoxypropane and the like can be mentioned. Two or more kinds of such compounds having two or more ether bonds existing via one or more atoms can be used in combination.

Examples of the cyclic ether include tetrahydrofuran, 1,3-dioxolane, 2-methyltetrahydrofuran, 2,5-dimethyltetrahydrofuran, 2,2,5,5-tetramethyltetrahydrofuran, 2,2-dimethyltetrahydrofuran, tetrahydro. Pyran, 1,4-dioxane, 2-methyltetrahydropyran, 2,6-dimethyltetrahydropyran, 2,
2,6,6-tetramethyltetrahydropyran and the like can be mentioned. Two or more kinds of such cyclic ethers can be used in combination.

When a reaction product of a chromium salt and a metal amide is supported on an inorganic oxide solid, pentane, hexane,
Performed in an inert hydrocarbon such as heptane, cyclohexane, benzene, toluene and the like. The amount of chromium atoms supported on the inorganic oxide solid is 0.01 to 10 wt%, preferably 0.1 to 5 wt%. The reaction temperature is -78 ° C to the boiling point of the solvent, preferably -20 ° C to 50 ° C, and the reaction time is 10 minutes to 24 hours, preferably 30 minutes to 5 hours. After the supporting reaction, a solid component having good fluidity can be obtained by a method of removing the solvent under vacuum or a method of separating the solvent by filtration.

When the above solid component is treated with alumoxane, it is carried out in an inert hydrocarbon such as pentane, hexane, heptane, cyclohexane, benzene, toluene and the like. The aluminum atom in the alumoxane used for the treatment has an aluminum / chromium molar ratio of 1 to 1000, preferably 5 to 10 relative to the chromium atom in the solid component.
It is preferable to carry out the treatment in such an amount that it becomes zero. The reaction temperature is -78 ° C to the boiling point of the solvent, preferably -20 ° C to 50.
℃, the reaction time is 10 minutes to 24 hours, preferably 30
Minutes to 5 hours. After the treatment, the solid catalyst component having good fluidity can be obtained by the method of removing the solvent under vacuum or the method of separating by filtration.

When the above solid catalyst component is treated with an electron donor compound, it is carried out in an inert hydrocarbon such as pentane, hexane, heptane, cyclohexane, benzene, toluene and the like. With respect to the chromium atom in the solid component, the electron donor compound used for the treatment has an electron donor compound / chromium molar ratio of 0.001 to 100, preferably 0.0.
It is preferable to carry out the treatment in an amount such that it becomes 1 to 50. The reaction temperature is -78 ° C to the boiling point of the solvent, preferably -20 ° C to
The reaction time is 50 ° C. and the reaction time is 10 minutes to 24 hours, preferably 30 minutes to 5 hours. After the treatment, a solid catalyst having good fluidity can be obtained by removing the solvent under vacuum or separating by filtration.

In carrying out the method of the present invention, a liquid phase reaction using a solvent or a gas phase reaction is possible as a method for trimerizing ethylene. As the solvent used in the liquid phase reaction, propane, butane, isobutane, pentane, hexane, heptane, octane, cyclohexane, methylcyclohexane, a linear or alicyclic saturated hydrocarbon such as decalin, benzene, toluene, xylene, ethylbenzene. Aromatic hydrocarbons such as tetralin, chain chlorinated hydrocarbons such as chloroform, methylene chloride, dichloroethane, trichloroethane and tetrachloroethane, and chlorinated aromatic hydrocarbons such as chlorobenzene and dichlorobenzene are used. Of these solvents,
Straight-chain or alicyclic saturated hydrocarbons are preferred. Also,
1-hexene itself can also be used as a solvent.

The temperature for the trimerization reaction of ethylene is usually 0 to 2
The temperature is 50 ° C., preferably 0 to 150 ° C., and the pressure is from normal pressure to 250 Kg / cm ² , but 100 Kg / cm ²
The following is sufficient. The reaction can be carried out batchwise or continuously. The residence time is in the range of 1 minute to 20 hours. Further, hydrogen may be allowed to coexist during the reaction.

In carrying out the trimerization of ethylene by the method of the present invention, as a method of introducing a catalyst, 1) a reaction product of a chromium salt and a metal amide, an inorganic oxide solid, an alumoxane and an electron donor compound are respectively placed in a reactor. 2) a method of introducing a solid component obtained by supporting a reaction product of a chromium salt and a metal amide on an inorganic oxide solid, an alumoxane, and an electron donor compound into a reactor,
3) A method in which the solid catalyst component and the electron donor compound obtained by treating the solid component with alumoxane are introduced into a reactor, respectively, and 4) a solid obtained by treating the solid catalyst component with the electron donor compound. With any of the methods of introducing the catalyst into the reactor, highly pure 1-hexene can be selectively produced. In any of 1) to 4), the amount of chromium atoms introduced or supported on the inorganic oxide solid is 0.01 to 10 wt%, preferably 0.1 to 5 wt%, and used for introducing or treating chromium atoms. The aluminum atom in the alumoxane has an aluminum / chromium molar ratio of 1 to 1000, preferably 5
˜100, the electron donor compound used for introducing or treating with respect to chromium atom is carried out in an amount such that the electron donor compound / chromium molar ratio is 0.001 to 100, preferably 0.01 to 50. .

The 1-hexene obtained in the present invention can be used as a comonomer in the production of an olefin polymer such as a copolymer of ethylene and 1-hexene, or as a raw material in the production of various organic compounds. Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples.

[0020]

EXAMPLES Example 1 (1) Reaction of Chromium Salt with Metal Amide 30 ml of tetrahydrofuran was added to 1.93 g (12.2 mmol) of anhydrous chromic chloride to prepare a slurry. After cooling to 0-3 ° C in an ice bath, 1.0mo manufactured by Aldrich
l / l 36.6 ml (36.6 mmol) of a hexane solution of lithium (bistrimethylsilyl) amide was added. After stirring at 25 ° C. for 4 hours to confirm that the chromic chloride had completely disappeared, the solvent was completely removed under vacuum. 100 ml of hexane was added to the obtained dark green mass to dissolve it, and the mixture was filtered through a glass filter to remove by-produced lithium chloride. When measuring the chromium concentration of the obtained solution,
0.12 mmol-Cr / ml (6.2 mg-Cr / m
l). (2) Trimerization of ethylene 600 ml of heptane, 60 ml in a 1.5 L autoclave
0.2 g of DAVISON 952 grade silica calcined at 0 ° C. for 4 hours, 0.32 ml of the above chromium solution, and 1.2 mol / mol of isobutylalumoxane manufactured by Tosoh Akzo.
l hexane solution 0.96 ml, 1,2-dimethoxyethane 0.01 mol / l heptane solution 0.96 ml
Was charged in sequence. After heating to 100 ° C, hydrogen is added at 3 Kg / c
m ² and 30 kg / cm ^{2 of} ethylene were successively introduced to start the reaction. After that, keep the total pressure constant and keep the reaction temperature at 100 ° C.
Maintained. One hour later, ethanol was injected to stop the reaction. The reactor was cooled to room temperature, degassed, and the product was quantified by gas chromatography. The results are shown in Table 1. Highly active and highly pure 1-hexene was selectively obtained with little polyethylene by-product.

Example 2 (1) Preparation of solid component 30 ml of hexane was added to 2.0 g of DAVISON 952 grade silica calcined at 600 ° C. for 4 hours to form a slurry. 3.2 ml of the chromium solution obtained in Example 1 (1) was added at 40 ° C., and the mixture was stirred for 1 hour. The solvent was removed under vacuum to give a solid component. (2) Ethylene trimerization In a 1.5 L autoclave, 600 ml of heptane, 0.2 g of the above-mentioned solid components, 1.2 mol / l hexane solution of isobutylalumoxane manufactured by Tosoh Akzo 0.96 m
0.01 mol / l of 1,1,2-dimethoxyethane
0.96 ml of a heptane solution was sequentially charged. After heating to 100 ° C., hydrogen is 3 kg / cm ² , ethylene is 30 kg / cm ² .
cm ^{2 were} sequentially introduced to start the reaction. Thereafter, the total pressure was kept constant, and the reaction temperature was kept at 100 ° C. One hour later, ethanol was injected to stop the reaction. The reactor was cooled to room temperature, degassed, and the product was quantified by gas chromatography. The results are shown in Table 1.

Example 3 (1) Preparation of solid catalyst component 30 ml of hexane was added to 2.0 g of DAVISON 952 grade silica calcined at 600 ° C. for 4 hours to form a slurry. 3.2 ml of the chromium solution obtained in Example 1 (1) was added at 40 ° C., and the mixture was stirred for 1 hour. The solvent was removed under vacuum to give a solid component. 30 ml of hexane was added to 2.0 g of this solid component to prepare a slurry. Tosoh at 25 ℃
1.2 mol / l of isobutylalumoxane manufactured by Akzo
9.6 ml of hexane solution was added and stirred for 2 hours.
The solvent was removed under vacuum to give a solid catalyst component. (2) Ethylene trimerization In a 1.5 L autoclave, 600 ml of heptane, 0.2 g of the above solid catalyst component, and 0.96 ml of a 0.01 mol / l heptane solution of 1,2-dimethoxyethane were sequentially charged. After heating to 100 ° C., hydrogen was added at 3 Kg / cm ² ,
Ethylene was sequentially introduced at 30 Kg / cm ² to start the reaction. Thereafter, the total pressure was kept constant, and the reaction temperature was kept at 100 ° C. One hour later, ethanol was injected to stop the reaction. The reactor was cooled to room temperature, degassed, and the product was quantified by gas chromatography. The results are shown in Table 1.

[0023]Example 4 (1) Preparation of solid catalyst 2.0 g of the solid catalyst component obtained in Example 1 (1)
30 ml of sun was added to make a slurry. 1,2-at 25 ° C
0.1 mol / l heptane solution of dimethoxyethane
0.96 ml was added and stirred for 2 hours. Solvent under vacuum
Was removed to obtain a solid catalyst. (2) Trimerization of ethylene 600 ml of heptane in the autoclave of 1.5 L, the above
0.2 g of solid catalyst was charged. After heating to 100 ℃, hydrogen
3 Kg / cm^Two , Ethylene 30 kg / cm ^Two Sequential guidance
It was turned on and the reaction started. After that, keep the total pressure constant and keep the reaction temperature
The temperature was maintained at 100 ° C. 1 hour later, press-in ethanol
Then the reaction was stopped. Cool reactor to room temperature and degas
Then, the product was quantified by gas chromatography. Table of results
Shown in 1.

Example 5 The reaction was carried out in the same manner as in Example 1 (2) except that the electron donor compound was tetrahydrofuran in Example 1 (2). The results are shown in Table 1.

Example 6 The reaction was carried out in the same manner as in Example 2 (2) except that the electron donor compound was tetrahydrofuran in Example 2 (2). The results are shown in Table 1.

Example 7 In Example 3 (2), the reaction was performed in the same manner as in Example 3 (2) except that the electron donor compound was tetrahydrofuran. The results are shown in Table 1.

Example 8 The reaction was carried out in the same manner as in Example 4 (1) except that the electron donor compound was tetrahydrofuran in Example 4 (1). The results are shown in Table 1.

Example 9 In Example 3, the amount of chromium atoms supported on the inorganic oxide solid was 0.5 wt%, the amount of isobutylalumoxane added was 4.8 ml, and the amount of 1,2-dimethoxyethane added was 0. The reaction was performed in the same manner as in Example 3 except that the amount was 48 ml. The results are shown in Table 1.

Example 10 In Example 3 (1), the aluminum atom in isobutylalumoxane was aluminum / chromium molar ratio = 6.
The reaction was carried out in the same manner as in Example 3 (1) except that 0 was used. The results are shown in Table 1.

Example 11 In Example 3 (2), 1,2-dimethoxyethane /
Example 3 except that the chromium molar ratio was 0.5.
The reaction was carried out in the same manner as (2). The results are shown in Table 1.

Example 12 In Example 7, the reaction was carried out in the same manner as in Example 7, except that the molar ratio of tetrahydrofuran / chromium was 0.5. The results are shown in Table 1.

Example 13 In Example 3 (2), the electron donor compound was 1,4-
The reaction was performed in the same manner as in Example 3 (2) except that dioxane was used. The results are shown in Table 1.

Example 14 In Example 3 (2), the electron donor compound was 1,3-
Example 3 (2) except that dimethoxypropane was used.
The reaction was carried out in the same manner as The results are shown in Table 1.

Example 15 In Example 3 (2), the electron donor compound was 2,2-
The reaction was carried out in the same manner as in Example 3 (2) except that diisobutyl-1,3-dimethoxypropane was used. The results are shown in Table 1.

Example 16 Example 3 is the same as Example 3 (1) except that the alumoxane is methylalumoxane manufactured by Tosoh Akzo.
The reaction was carried out in the same manner as (1). The results are shown in Table 1.

Example 17 Example 3 (2) is the same as Example 3 (2) except that hydrogen is not introduced and the ethylene pressure is 15 Kg / cm ^2.
The reaction was carried out in the same manner as The results are shown in Table 1.

Example 18 The reaction was carried out in the same manner as in Example 3 (2) except that hydrogen was not introduced, ethylene pressure was 15 Kg / cm ² , and reaction temperature was 120 ° C. in Example 3 (2). went. The results are shown in Table 1.

Example 19 The reaction was carried out in the same manner as in Example 3 (2) except that hydrogen was not introduced and the ethylene pressure was 7 Kg / cm ^{2 in} Example 3 (2). The results are shown in Table 1.

Example 20 Example 3 (2) was repeated except that hydrogen was not introduced, the ethylene pressure was 7 Kg / cm ² , and the reaction temperature was 120 ° C.
The reaction was carried out in the same manner as in Example 3 (2). Table 1 shows the results
Shown in

Example 21 In Example 12, no hydrogen was introduced and the ethylene pressure was adjusted to 7
The reaction was carried out in the same manner as in Example 12 except that the reaction temperature was Kg / cm ² and the reaction temperature was 120 ° C. The results are shown in Table 1.

Comparative Example 1 In Example 3 (1), instead of the reaction product of a chromium salt as a chromium compound and a metal amide, an equimolar STR was used.
The reaction was performed in the same manner as in Example 3 except that a hexane solution of chromium (III) 2-ethylhexanoate manufactured by EM was used. The results are shown in Table 1. A large amount of polyethylene is by-produced,
The activity and the purity of 1-hexene were low.

Comparative Example 2 (1) Preparation of Chromium Complex 0.79 g of sodium hydride and tetrahydrofuran 15
ml was added, and 1.0 ml of pyrrole dissolved in 5 ml of tetrahydrofuran was added dropwise thereto. After stirring at room temperature for 1 hour, this solution was added dropwise to 0.79 g of chromic chloride suspended in 25 ml of tetrahydrofuran. After dripping, 20
Heated to reflux for an hour. After filtering off the precipitate, the solvent was distilled off,
A black chromium complex was obtained. (2) Example 3 In Example 3, except that an equimolar amount of the chromium complex of (1) with respect to chromium atom is used instead of the reaction product of the chromium salt and the metal amide as the chromium compound. The reaction was performed in the same manner as in. The results are shown in Table 1. A large amount of polyethylene was produced as a by-product, and the result was that the activity of 1-hexene was extremely low.

Comparative Example 3 The same reaction as in Comparative Example 2 was carried out except that triethylaluminum was used instead of isobutylalumoxane in Comparative Example 2 (2). The results are shown in Table 1. A large amount of polyethylene was by-produced, resulting in a low purity of 1-hexene.

Comparative Example 4 The reaction was carried out in the same manner as in Example 3 except that triethylaluminum was used instead of isobutylalumoxane in Example 3 (1). The results are shown in Table 1. 1-
As a result, the activity of hexene was extremely low.

Comparative Example 5 The reaction was carried out in the same manner as in Example 3 (2) except that 1,2-dimethoxyethane was not used in Example 3 (2). The results are shown in Table 1. As a result, the selectivity of 1-hexene was low.

Comparative Example 6 The reaction was carried out in the same manner as in Example 7 except that tetrahydrofuran was not used. The results are shown in Table 1. As a result, the selectivity of 1-hexene was low.

Comparative Example 7 The reaction was carried out in the same manner as in Example 1 except that DAVISON 952 grade silica was not used. The results are shown in Table 1. The activity and the selectivity of 1-hexene were low.

[0048]

[Table 1]

[0049]

Industrial Applicability By carrying out the present invention, ethylene can be trimerized to produce highly pure 1-hexene selectively and efficiently, which is extremely valuable industrially.

Front Page Continuation (72) Inventor Masakazu Yamamoto, Oita City, Oita Prefecture, No. 2 Nakasu, Showa Denko K.K.

Claims (10)

[Claims] 1. A method for trimerizing ethylene, which comprises using a catalyst comprising a reaction product of a chromium salt and a metal amide, an inorganic oxide solid, an alumoxane and an electron donor compound. 2. The trimerization of ethylene according to claim 1, wherein a catalyst comprising a solid component obtained by supporting a reaction product of a chromium salt and a metal amide on an inorganic oxide solid, an alumoxane, and an electron donor compound is used. Method. 3. The method for trimerizing ethylene according to claim 1, wherein a catalyst comprising a solid catalyst component obtained by treating the solid component according to claim 2 with alumoxane and an electron donor compound is used. 4. The method for trimerizing ethylene according to claim 1, wherein a solid catalyst obtained by treating the solid catalyst component according to claim 3 with an electron donor compound is used. 5. The method for trimerizing ethylene according to claim 1, wherein the chromium salt is chromium chloride or chromium chloride. 6. The method for trimerizing ethylene according to claim 1, wherein the metal amide is an alkali metal amide salt, an alkaline earth metal amide salt, or a silylamide salt. 7. The method for trimerizing ethylene according to claim 1, wherein the metal amide is a bis (trialkyl) amide salt or a bis (trialkylsilyl) amide salt. 8. The method for trimerizing ethylene according to claim 1, wherein the alumoxane is a polyalkylalumoxane. 9. The method for trimerizing ethylene according to claim 1, wherein the electron donor compound is a compound having two or more ether bonds existing through one or more atoms. 10. The method for trimerizing ethylene according to claim 1, wherein the electron donor compound is a cyclic ether.