A phosphine-containing compound and its preparation method and application as ligand of ethylene oligomerization catalyst composition

Abstract

The present invention provides a phosphine-containing compound and a preparation method thereof and an application thereof as a ligand of an ethylene oligomerization catalyst composition. The phosphine-containing compound has a structure as shown in Formula I: wherein R1, R2, and R3 are independently selected from hydrogen, a C1-C20 chain alkyl group, a C3-C20 cycloalkyl group, a heterocycloalkyl group, a substituted or unsubstituted C6-C20 aryl group, a halogen, an alkoxy group, a phenoloxy group, an amine group, and a phosphine-based substituent; and R1, R2, and R3 are the same or different. When used as an ethylene oligomerization catalyst, it can selectively prepare 1-hexene and 1-octene, and also has excellent total selectivity of C8 and C6.

Description

Technical Field

[0001] The present invention belongs to the field of compounds, and relates to a phosphine-containing compound (NPN-type compound), and specifically to the "NPN-type" phosphine-containing compound, a preparation method thereof, and an application thereof as a ligand of an ethylene oligomerization catalyst composition. Background Art

[0002] Linear α-olefins such as 1-octene and 1-hexene are important chemical products and intermediates, and are widely used in the fields of polyethylene comonomers, plasticizer alcohols, flavors and fragrances, synthetic lubricants and oil additives. 1-octene and 1-hexene can significantly improve the density of polyethylene and improve its mechanical properties such as tear resistance and tensile strength when used as comonomers. When used as plasticizer alcohols, polyethylene products can have better low-temperature flexibility, processability, and outdoor weather resistance, and are particularly suitable for the manufacture of cables and wires, automotive accessories or decorative parts.

[0003] In recent years, along with the continuous development of polyolefin industry, the demand for alpha-olefin has increased rapidly worldwide, wherein, most alpha-olefin is prepared by ethylene polymerization. The carbon number distribution of the product obtained by traditional ethylene polymerization technology conforms to Schulz-Flory distribution, and this distribution makes the content of 1-hexene and 1-octene in the polymerization product lower. US 6184428 discloses a nickel catalyst, and this catalyst adopts boride as a cocatalyst, can catalyze ethylene to obtain a mixture of alpha-olefin, wherein the content of 1-octene accounts for 19%. Based on Shell SHOP process, US 3635937, US 3686351 and US3676523 disclose similar catalyst systems, and the modified system involves OP bridged ligand, and the synthesis steps are more and the toxicity is larger, and the content of 1-octene accounts for 11% in the product. Other ethylene polymerization processes, such as the Chevron process (DE1443927) of Gulf Oil Company and the process of Ethyl Corporation (US 3906053), have a 1-octene content of 13-25%. WO 99 / 02472 discloses an iron-based catalyst, and the polymerization products obtained by the catalyst are also widely distributed, and the content of 1-octene is also low (<3%). Sasol's patent WO 04056478 discloses a PNP skeleton catalyst, in the ethylene tetramerization reaction, the C8 component selectivity is about 66wt%, the C6 component selectivity is about 21wt%, wherein the content of 1-hexene in the C6 component is only 82%, and the total selectivity of 1-hexene and 1-octene is about 84%. US 20100137669 discloses a "PCCP" type symmetrical skeleton catalyst, in the ethylene tetramerization reaction, the catalyst is more stable than the PNP system, and the total selectivity of 1-hexene and 1-octene is about 84%. Summary of the invention

[0004] The present invention provides a phosphine-containing compound having a structure as shown in Formula I:

[0005]

[0006] Wherein, R1, R2, and R3 can be independently selected from hydrogen, C1-C20 chain alkyl, C3-C20 cycloalkyl, heterocycloalkyl, substituted or unsubstituted C6-C20 aryl, halogen, alkoxy, phenoloxy, amino, phosphino substituents, etc.;

[0007] R1, R2, and R3 may be the same or different.

[0008] Preferably, R1, R2, and R3 can be independently selected from hydrogen, C1-C6 chain alkyl, C3-C6 cycloalkyl, heterocycloalkyl, substituted or unsubstituted C6-C12 aryl, halogen, alkoxy, phenoloxy, amino, phosphino substituents, etc.

[0009] Also preferably, R1, R2, and R3 can be independently selected from hydrogen, methyl, ethyl, isopropyl, tert-butyl, cyclopropyl, C6 aryl, halogen, alkoxy, phenoloxy, amino, phosphino substituents, etc.

[0010] According to an embodiment of the present invention, the phosphine-containing compound has a structure as shown in Formula I-1 to Formula I-8:

[0011]

[0012]

[0013]

[0014] The present invention also provides the use of the phosphine-containing compound as a ligand of an ethylene oligomerization catalyst composition.

[0015] According to an embodiment of the present invention, the ethylene oligomerization catalyst composition comprises a transition metal compound (ie, a catalyst), a co-catalyst and the phosphine-containing compound.

[0016] According to an embodiment of the present invention, the transition metal compound is selected from at least one of chromium compounds, molybdenum compounds, iron compounds, titanium compounds, zirconium compounds and nickel compounds; preferably selected from chromium compounds, for example, at least one selected from chromium acetylacetonate, chromium isooctanoate, tri(tetrahydrofuran)chromium trichloride and di(tetrahydrofuran)chromium dichloride.

[0017] According to an embodiment of the present invention, the cocatalyst is selected from aluminum-containing cocatalysts and / or boron-containing cocatalysts. Preferably, the aluminum-containing cocatalyst is selected from at least one of alkyl aluminum, alkoxy aluminum and alkyl aluminum halide. Preferably, the boron-containing cocatalyst is selected from at least one of trifluoroborane, triphenylborane, tri(4-fluorophenyl)borane, tri(pentafluorophenyl)borane, tri(3,5-difluorophenyl)borane, tri(2,4,6-trifluorophenyl)borane, triphenylmethane tetrapentafluorophenyl boron and trisubstituted amine hydrogen tetrapentafluorophenyl boron.

[0018] According to an embodiment of the present invention, when the co-catalyst is selected from an aluminum-containing co-catalyst, the molar ratio of the transition metal compound, the phosphine-containing compound and the co-catalyst is 1:(1-1.5):(300-500), for example 1:1.2:400.

[0019] According to an embodiment of the present invention, when the co-catalyst is selected from a boron-containing co-catalyst, the molar ratio of the transition metal compound, the phosphine-containing compound and the co-catalyst is 1:(1-1.5):(1-5), for example 1:1.2:1.2.

[0020] The present invention also provides an ethylene oligomerization reaction method, which comprises using the above phosphine-containing compound as a ligand of an ethylene oligomerization catalyst composition.

[0021] Preferably, the ethylene oligomerization catalyst composition has the meaning as indicated above.

[0022] According to an embodiment of the present invention, the oligomerization reaction is carried out in a solvent. For example, the solvent is selected from aliphatic hydrocarbon solvents and / or aromatic hydrocarbon solvents; the aliphatic hydrocarbon solvent is preferably selected from at least one of n-heptane, pentane, cyclohexane, methylcyclohexane and ethylcyclohexane; the aromatic hydrocarbon solvent is preferably selected from at least one of toluene, xylene, monochlorobenzene, dichlorobenzene and dichlorotoluene.

[0023] According to an embodiment of the present invention, the total selectivity of 1-octene and 1-hexene in the oligomerization reaction is not less than 50%, such as not less than 60%, not less than 80%, not less than 85%, preferably the total selectivity is 90-99%.

[0024] The present invention also provides a method for selectively producing 1-hexene and 1-octene, which comprises selectively producing 1-hexene and 1-octene by selecting the above phosphine-containing compound as a ligand of an ethylene oligomerization catalyst composition.

[0025] According to an embodiment of the present invention, when the ethylene oligomerization catalyst composition is composed of chromium acetylacetonate, methylaluminoxane and a phosphine-containing compound, the phosphine-containing compound has a structure shown in Formula I-3 or Formula I-7, and tends to selectively generate 1-hexene. For example, the selectivity of 1-hexene is not less than 45%.

[0026] According to an embodiment of the present invention, when the ethylene oligomerization catalyst composition is composed of chromium acetylacetonate, methylaluminoxane and a phosphine-containing compound, the phosphine-containing compound has a structure shown in Formula I-1, I-2, I-4, I-5, I-6 or I-8, and tends to selectively generate 1-octene. For example, the selectivity of 1-octene is not less than 60%.

[0027] According to an embodiment of the present invention, when the ethylene oligomerization catalyst composition is composed of chromium isooctanoate, tris(pentafluorophenyl)boron and a phosphine-containing compound, the phosphine-containing compound has a structure shown in Formula I-3, and tends to selectively generate 1-hexene. For example, the selectivity of 1-hexene is not less than 80%.

[0028] According to an embodiment of the present invention, when the ethylene oligomerization catalyst composition is composed of a chromium compound, tris(pentafluorophenyl)boron and a phosphine-containing compound, the chromium compound is chromium acetylacetonate, CrCl3TFH or chromium isooctanoate, and the phosphine-containing compound has a structure shown in Formula I-2, I-3 or I-6, it tends to selectively generate 1-octene. For example, the selectivity of 1-octene is not less than 80%.

[0029] Beneficial Effects of the Invention

[0030] The phosphine-containing compound disclosed in the present invention is used for ethylene polymerization catalyst, which has better stability than the existing ethylene polymerization catalyst. The selectivity of the existing technology for 1-octene is only about 75% at most, and 1-hexene cannot be effectively and selectively prepared. At the same time, the ligand of the existing technology is easily lost during use, resulting in catalyst deactivation, and the catalyst needs to be replenished more frequently. The catalyst structure of the present invention is stable, the catalytic activity is higher, and the life of the catalyst is longer. Compared with the life of the known ethylene polymerization catalyst of up to ten minutes, the life of the catalyst of the present application is about thirty minutes; more importantly, the selectivity of the catalyst of the present invention is higher and more targeted. By changing the position of the substituent of the phosphine-containing compound, 1-hexene or 1-octene can be prepared with high selectivity, and then different olefins can be synthesized; the selection of a phosphine-containing compound with a suitable structure and chromium coordination can obtain a selectivity of more than 85% for 1-octene, and the total selectivity of C8 and C6 is above 92%, especially when it is catalyzed with a boron compound co-catalyst, the total selectivity can be as high as 96% or more, which greatly reduces the generation of by-products, improves the synthesis efficiency and reduces the separation cost. DETAILED DESCRIPTION

[0031] [Preparation method of phosphine-containing compound]

[0032] The method for preparing the aforementioned phosphine-containing compound comprises the following steps: reacting a compound of formula A with a compound of formula B to prepare the phosphine-containing compound;

[0033] Compound of formula A: Compound of formula B:

[0034] Wherein, R is selected from hydrogen, C1-C20 chain alkyl, C3-C20 cycloalkyl, heterocycloalkyl, substituted or unsubstituted C6-C20 aryl, halogen, alkoxy, phenoloxy, amino, phosphino substituents, etc.;

[0035] R3 has the options shown above;

[0036] X represents a halogen, such as Cl, Br or I.

[0037] For example, the compound of formula A is The compound of formula B is

[0038] In the preparation method, the compound of formula A and the compound of formula B are added to the reaction system in the form of solutions. For example, the ether solution of the compound of formula A and the ether solution of the compound of formula B are added to the reaction system.

[0039] The preparation method comprises the following steps:

[0040] (1) adding an n-butyllithium solution (e.g., an n-butyllithium solution in n-hexane) into a reaction vessel and cooling the vessel to -75 to -80°C;

[0041] (2) adding a solution of the compound of formula A to the system of step (1), and keeping the temperature at -75 to -80°C after the addition is complete;

[0042] (3) After step (2) is completed, a solution of the compound of formula B is added to the system, and after the addition is complete, the mixture is kept warm at -75 to -80°C;

[0043] (4) After step (3) is completed, the system is heated to room temperature for reaction, and then post-treated to obtain the phosphine-containing compound.

[0044] Preferably, the solution of the compound of formula A and the solution of the compound of formula B are added to the system in a dropwise manner. Preferably, the temperature of the system is kept below -70°C during the dropwise addition process.

[0045] In the above step (2), the insulation time is 3-5 hours, for example 4 hours.

[0046] In the above step (3), the insulation time is 1-3 hours, for example 2 hours.

[0047] In the above step (4), the reaction time at room temperature is 1-5 hours, for example, 2 hours.

[0048] In the above step (4), the post-treatment includes: extracting the reaction system with dilute sulfuric acid, retaining the aqueous phase, adjusting the pH value of the aqueous phase to alkaline (for example, 7.5-8.5), precipitating solids, separating and drying the solids, and obtaining the phosphine-containing compound.

[0049] The technical scheme of the present invention will be further described in detail below in conjunction with specific embodiments. It should be understood that the following embodiments are only exemplary descriptions and explanations of the present invention and should not be construed as limiting the scope of protection of the present invention. All technologies implemented based on the above content of the present invention are included in the scope that the present invention is intended to protect.

[0050] Unless otherwise specified, the raw materials and reagents used in the following examples are commercially available or can be prepared by known methods.

[0051] The obtained products were tested in the following examples, and the test process involved included:

[0052] The ethylene oligomerization products were analyzed using an Agilent technologies 7890A gas chromatograph (GC-FID) with n-heptylene as the internal standard to calculate the catalytic activity and selectivity of ethylene oligomerization products.

[0053] Examples A1-A8 are used to prepare phosphine-containing compounds.

[0054] [Example A1] Phosphine-containing ligand 1 and its preparation

[0055]

[0056] The preparation method of the phosphine-containing ligand 1 is based on the above reaction formula, and the specific steps are as follows:

[0057] The three-necked flask was evacuated with nitrogen three times, 5 ml of n-butyl lithium (2.4 M n-hexane solution) was added, and the reaction vessel was cooled to -78 ° C. The ether solution of 2-bromopyridine (12 mmol, 8 ml) was slowly added dropwise, and the temperature was kept below -70 ° C during the addition process. After the addition was completed, it was kept warm at -78 ° C for 4 hours. The ether solution of dichlorophenylphosphine (6 mmol, 8 ml) was slowly added dropwise to the reaction, and the temperature was kept below -70 ° C during the addition process. After the addition was completed, it was kept warm at -78 ° C for 2 hours, and then the reaction system was slowly heated to room temperature (25 ° C) and reacted for 2 hours. The reaction system was extracted twice with 20 ml of 2M dilute sulfuric acid, the aqueous phases were combined, and the saturated sodium hydroxide aqueous solution was adjusted to pH 8. A yellow solid was precipitated, filtered, and dried. A yellow solid was obtained with a yield of 70%. 1H-NMR (CDCl3, 400 MHz): δ7.17-7.20 (m, 2H), 7.24 (dd, 2H), 7.36-7.41 (m, 3H), 7.48-7.52 (m, 2H), 7.58 (tt, 2H), 8.71 (d, 2H), proving that the obtained solid was the phosphine-containing ligand 1.

[0058] [Example A2] Phosphine-containing ligand 2 and its preparation

[0059]

[0060] The preparation method of phosphine-containing ligand 2 refers to the above reaction formula, and the specific steps are as follows:

[0061] Using 4-methyl-2-bromopyridine and dichlorophenylphosphine as raw materials, the synthesis steps were the same as the preparation of ligand 1, and a yellow solid was obtained with a yield of 50%. H-NMR (CDCl3, 400MHz): δ2.22 (s, 6H), 7.01 (s, 2H), 7.16 (d, 2H), 7.40-7.41 (m, 5H), 8.50 (d, 2H), proving that the obtained solid was phosphine-containing ligand 2.

[0062] [Example A3] Phosphine-containing ligand 3 and its preparation

[0063]

[0064] The preparation method of the phosphine-containing ligand 3 is based on the above reaction formula, and the specific steps are as follows:

[0065] Using 6-methyl-2-bromopyridine and dichlorophenylphosphine as raw materials, the synthesis steps were the same as the preparation of ligand 1, and a yellow solid was obtained with a yield of 55%. H-NMR (CDCl3, 400MHz): δ2.50 (s, 6H), 7.05-7.15 (m, 6H), 7.40-7.50 (m, 3H), 7.67 (dd, 2H), indicating that the obtained solid was phosphine-containing ligand 3.

[0066] [Example A4] Phosphine-containing ligand 4 and its preparation

[0067]

[0068] The preparation method of phosphine-containing ligand 4 is based on the above reaction formula, and the specific steps are as follows:

[0069] Using 5-methyl-2-bromopyridine and dichlorophenylphosphine as raw materials, the synthesis steps were the same as the preparation of ligand 1 to obtain a yellow solid with a yield of 59%. H-NMR (CDCl3, 400MHz): δ2.16 (s, 6H), 7.14-7.18 (m, 4H), 7.41-7.44 (m, 3H), 7.57 (d, 2H), 8.33 (s, 2H), indicating that the obtained solid is phosphine-containing ligand 4.

[0070] [Example A5] Phosphine-containing ligand 5 and its preparation

[0071]

[0072] The preparation method of phosphine-containing ligand 5 is based on the above reaction formula, and the specific steps are as follows:

[0073] Using 2-bromopyridine and dichloro(4-methylphenyl)phosphine as raw materials, the synthesis steps were the same as the preparation of ligand 1 to obtain a yellow solid with a yield of 66%. H-NMR (CDCl3, 400MHz): δ2.21 (s, 3H), 7.10-7.15 (m, 4H), 7.28 (dd, 2H), 7.41-7.45 (m, 2H), 7.63-7.67 (m, 2H), 8.39 (d, 2H), indicating that the obtained solid was phosphine-containing ligand 5.

[0074] [Example A6] Phosphine-containing ligand 6 and its preparation

[0075]

[0076] The preparation method of phosphine-containing ligand 6 refers to the above reaction formula, and the specific steps are as follows:

[0077] Using 2-bromo-5-isopropylpyridine and dichlorophenylphosphine as raw materials, the synthesis steps were the same as the preparation of ligand 1, and a yellow solid was obtained with a yield of 67%. H-NMR (CDCl3, 400MHz): δ1.21 (d, 12H); 2.89 (m, 2H), 7.16 (dd, 2H), 7.19 (d, 2H), 7.41-7.46 (m, 5H), 8.40 (d, 2H), indicating that the obtained solid was phosphine-containing ligand 6.

[0078] [Example A7] Phosphine-containing ligand 7 and its preparation

[0079]

[0080] The preparation method of phosphine-containing ligand 7 is based on the above reaction formula, and the specific steps are as follows:

[0081] Using 2-bromo-6-isopropylpyridine and dichlorophenylphosphine as raw materials, the synthesis steps were the same as the preparation of ligand 1, and a yellow solid was obtained with a yield of 40%. H-NMR (CDCl3, 400MHz): δ1.31 (d, 12H); 3.40 (m, 2H), 7.13-7.18 (m, 6H), 7.39-7.45 (m, 3H), 7.60 (dd, 2H), indicating that the obtained solid was phosphine-containing ligand 7.

[0082] [Example A8] Phosphine-containing ligand 8 and its preparation

[0083]

[0084] The preparation method of phosphine-containing ligand 8 refers to the above reaction formula, and the specific steps are as follows:

[0085] Using 2-bromo-5-tert-butylpyridine and dichlorophenylphosphine as raw materials, the synthesis steps were the same as the preparation of ligand 1, and a yellow solid was obtained with a yield of 51%. H-NMR (CDCl3, 400MHz): δ1.29 (s, 18H); 7.15 (dd, 2H), 7.20 (d, 2H), 7.42-7.48 (m, 5H), 8.43 (d, 2H), indicating that the obtained solid was phosphine-containing ligand 8.

[0086] [Example B1]

[0087] The phosphine-containing ligands 1-8 obtained above were subjected to ethylene oligomerization reaction under the following conditions:

[0088] A 300mL stainless steel polymerization autoclave was heated to 120°C, evacuated and replaced with nitrogen, and then filled with ethylene for replacement, and the temperature in the autoclave was reduced to 40°C. Dried n-hexane, 0.5μmol chromium acetylacetonate, phosphine-containing ligand, and methylaluminoxane (MAO) as a co-catalyst were added to the autoclave and mixed evenly, wherein the total volume of the mixed solution was 100mL, and the molar ratio of chromium acetylacetonate: phosphorus-containing compound: co-catalyst was 1:1.2:400. Ethylene was introduced, and the ethylene pressure was controlled to be 3MPa, and the ethylene polymerization reaction was carried out at a temperature of 50°C. After 30 minutes, 1mL of ethanol was added as a terminator to terminate the reaction. The temperature in the autoclave was reduced to room temperature (25°C), the gas phase product was collected in a gas metering tank, and the liquid phase product was collected in a conical flask. The gas and liquid phase products were measured separately and then analyzed by gas chromatography, and the catalyst activity and product composition were calculated. The results are listed in Table 1.

[0089] Table 1

[0090]

[0091] [Example B2]

[0092] The phosphine-containing ligands 2, 3, and 6 obtained above were subjected to ethylene oligomerization reaction under the following conditions:

[0093] A 300mL stainless steel polymerization autoclave was heated to 120°C, evacuated and replaced with nitrogen, then filled with ethylene for replacement, and the temperature in the autoclave was lowered to 40°C. Dried n-hexane, 0.5μmol catalyst, phosphine-containing compound as ligand, and tri(pentafluorophenyl)boron as co-catalyst were added to the autoclave and mixed evenly, wherein the total volume of the mixed solution was 100mL, and the molar ratio of chromium compound to phosphorus-containing ligand was 1:1.5. Ethylene was introduced, the ethylene pressure was controlled, and ethylene polymerization was carried out at the set temperature. After 30 minutes, 1mL of ethanol was added as a terminator to terminate the reaction. The temperature in the autoclave was lowered to room temperature (25°C), the gas phase product was collected in a gas metering tank, and the liquid phase product was collected in a conical flask. The gas and liquid phase products were measured separately and then analyzed by gas chromatography, and the catalyst activity and product composition were calculated. The results are listed in Table 2.

[0094] Table 2

[0095]

[0096]

[0097] It can be seen from the catalytic performance test results of the examples in Tables 1 and 2 that the catalytic system of the present invention containing phosphine-containing compounds has excellent ethylene tetramerization catalytic activity, and by changing the position of the substituent, 1-hexene and 1-octene can be selectively generated, and the catalytic activity and life are both high, and it has potential industrial application prospects.

[0098] The above is an explanation of the embodiments of the present invention. However, the present invention is not limited to the above embodiments. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method of using a phosphine-containing compound as a ligand of an ethylene oligomerization catalyst composition to selectively produce 1-hexene and 1-octene, characterized in that: The phosphine-containing compound has a structure of Formula I-1 to Formula I-6 and Formula I-8: The total selectivity of 1-octene and 1-hexene is not less than 80%.

2. The use according to claim 1, characterized in that The ethylene polymerization catalyst composition comprises a transition metal compound, a co-catalyst and the phosphine-containing compound.

3. The use according to claim 2, characterized in that: The transition metal compound is selected from at least one of chromium compounds, molybdenum compounds, iron compounds, titanium compounds, zirconium compounds and nickel compounds; the co-catalyst is selected from aluminum-containing co-catalysts and / or boron-containing co-catalysts.

4. The use according to claim 2, characterized in that: The transition metal compound is selected from chromium compounds.

5. The use according to claim 2, characterized in that: The transition metal compound is at least one selected from chromium acetylacetonate, chromium isooctanoate, tri(tetrahydrofuran)chromium trichloride and di(tetrahydrofuran)chromium dichloride.

6. The use according to claim 3, characterized in that: The aluminum-containing co-catalyst is selected from at least one of alkyl aluminum, alkoxy aluminum and alkyl aluminum halide; the boron-containing co-catalyst is selected from at least one of trifluoroborane, triphenylborane, tri(4-fluorophenyl)borane, tri(pentafluorophenyl)borane, tri(3,5-difluorophenyl)borane, tri(2,4,6-trifluorophenyl)borane, triphenylmethanetetrapentafluorophenylborane and trisubstituted amine hydrogentetrapentafluorophenylborane.

7. The use according to claim 3 or 6, characterized in that: When the co-catalyst is selected from an aluminum-containing co-catalyst, the molar ratio of the transition metal compound, the phosphine-containing compound and the co-catalyst is 1:(1-1.5):(300-500); When the co-catalyst is selected from a boron-containing co-catalyst, the molar ratio of the transition metal compound, the phosphine-containing compound and the co-catalyst is 1:(1-1.5):(1-5).

8. An ethylene oligomerization method, characterized in that: The method comprises using the phosphine-containing compound of claim 1 as a ligand of an ethylene oligomerization catalyst composition; and the total selectivity of 1-octene and 1-hexene in the ethylene oligomerization reaction is not less than 80%.

9. The method according to claim 8, characterized in that The ethylene oligomerization catalyst composition is the ethylene oligomerization catalyst composition according to any one of claims 2 to 7.

10. The method according to claim 8, characterized in that The oligomerization reaction is carried out in a solvent.

11. The method according to claim 8, characterized in that The total selectivity of 1-octene and 1-hexene in the oligomerization reaction is 90-99%.

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