A catalyst composition for olefin oligomerization, its preparation method and application

Abstract

The present invention provides a catalyst composition for olefin oligomerization, comprising: a main catalyst represented by formula (I), an alkylaluminum compound, cyclohexane and water. In formula (I), R1-R 11 are the same or different and each independently selected from hydrogen, C1-C6 alkyl, halogen, C1-C6 alkoxy and nitro; M is Fe(II), Co(II) or Ni(II). By using an alkylaluminum compound as an auxiliary agent, cyclohexane as a solvent, and simultaneously adding a specific amount of water, the present invention effectively improves the activity of the catalyst composition, reduces the yield of undesired C4 products, and at the same time increases the yield of desired C6-C 10 , C6-C 18 , C6-C 18 linear α-olefin products, and the ethylene oligomerization reaction can be carried out at a relatively high temperature condition that is easy to achieve and operate, greatly reducing the energy consumption.

Description

Technical Field

[0001] The present invention relates to the technical field of olefin oligomerization, and particularly relates to a catalyst composition for olefin oligomerization, a preparation method thereof, and an application thereof. Background Art

[0002] Linear α-olefins have extensive applications in fields such as ethylene copolymer monomers, synthesis intermediates of surfactants, alcohols for plasticizers, synthetic lubricants, and oil additives. In recent years, with the continuous development of the polyolefin industry, the demand for α-olefins has increased rapidly worldwide.

[0003] At present, the vast majority of α-olefins are prepared by ethylene oligomerization. The catalysts used in the ethylene oligomerization method mainly include nickel-based, chromium-based, zirconium-based, and aluminum-based catalysts, etc. In recent years, the Brookhart group (Brookhart, M et al, J. Am. Chem. Soc., 1998, 120, 7143 - 7144; WO99 / 02472, 1999), and the Gibson group (Gibson, V.C. et al, Chem. Commun., 1998, 849 - 850; Chem. Eur. J., 2000, 2221 - 2231) have respectively found that some tridentate pyridine imine complexes of Fe(II) and Co(II) can catalyze ethylene oligomerization. Not only is the catalytic activity of the catalyst very high, but also the selectivity of α-olefins is very high.

[0004] The Sun Wenhua research group of the Institute of Chemistry, Chinese Academy of Sciences reported a catalyst for ethylene oligomerization (Organometallics 2006, 25, 666 - 677). This catalyst is iron(II) chloride-2-acetyl-1,10-phenanthroline-2,6-dimethylaniline complex. Under the action of cocatalyst methylaluminoxane (MAO) or modified methylaluminoxane (MMAO), when the molar ratio of metal aluminum in the cocatalyst to the central metal in the main catalyst is 1000, the oligomerization and polymerization activity reaches a maximum of 3.9×10 7 g·mol(Fe) -1 ·h -1 , and, as the reaction temperature further increases, both the activity and the distribution coefficient decrease. However, whether it is MAO or MMAO as the cocatalyst, there are problems of too high cost and too large dosage. When used as a cocatalyst in large-scale ethylene oligomerization, it will inevitably lead to high production costs.

[0005] In addition, the research group led by Sun Wenhua also made an attempt with inexpensive cocatalysts in Chinese Patent (CN1850339A). When using iron(II) chloride-2-acetyl-1,10-phenanthroline-2,6-diethylaniline complex as the main catalyst and triethylaluminum as the cocatalyst, the catalytic activity was only 2.7×10 5 g·mol(Fe) -1 ·h -1 , which could not meet the industrial requirements. At the same time, for reaction temperatures below 40°C, chilled water is generally required as the reaction condensation medium, and a refrigeration unit needs to be equipped for refrigeration, increasing the process energy consumption. SUMMARY OF THE INVENTION

[0006] In view of the problems existing in the above-mentioned prior art, one of the objectives of the present invention is to provide a catalyst composition for olefin oligomerization, which has high catalytic activity, can reduce the yield of undesired C4 products, and at the same time increase the yield of desired C6-C 10 、C6-C 18 、C6-C 18 linear α-olefin products; more importantly, the catalyst composition provided by the present invention enables olefin oligomerization, especially ethylene oligomerization, to be carried out under relatively high temperatures (such as 60°C to 90°C) that are easy to achieve and operate. As a result, the ethylene oligomerization reaction involving the catalyst composition of the present invention can use condensed water as the cooling medium, greatly reducing the energy consumption.

[0007] Another objective of the present invention is to provide a preparation method of the catalyst composition corresponding to the first objective.

[0008] A further objective of the present invention is to provide an application of the catalyst composition corresponding to the above objectives.

[0009] To achieve the first objective, the technical solution adopted by the present invention is as follows:

[0010] A catalyst composition for olefin oligomerization, comprising: a main catalyst represented by formula (I), an alkylaluminum compound, cyclohexane, and water,

[0011]

[0012] In formula (I), R1-R 11 are the same or different, and each independently selected from hydrogen, C1-C6 alkyl, halogen, C1-C6 alkoxy, and nitro; M is Fe(II), Co(II), or Ni(II).

[0013] In the prior art, aromatic hydrocarbon organic solvents such as toluene or expensive alkane organic solvents such as heptane are usually used in the catalyst composition for olefin oligomerization, especially ethylene oligomerization. However, the inventors of the present application have found in their research that using cyclohexane as a solvent, simultaneously using an alkyl aluminum compound and adding a specific content of water can effectively improve the activity of the catalyst composition, reduce the yield of undesired C4 products, and at the same time increase the yield of desired C6-C 10 C6-C 18 C6-C 18 yield of linear α-olefin products. More importantly, the catalyst composition provided by the present invention enables the ethylene oligomerization reaction to be carried out under relatively high temperature conditions that are easy to achieve and operate, and thus the ethylene oligomerization reaction involving the catalyst composition of the present invention can use condensed water as a cooling medium, reducing energy consumption. In addition, the ethylene oligomerization reaction involving the catalyst composition of the present invention is initiated rapidly, operates smoothly, and has good repeatability.

[0014] In the present invention, the term "C1-C6 alkyl" refers to a saturated straight-chain or branched hydrocarbon group containing 1-6 carbon atoms. As C1-C6 alkyl, mention may be made of methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, isopentyl, sec-pentyl, n-hexyl and sec-hexyl; particularly preferred are methyl, ethyl, n-propyl and isopropyl.

[0015] In the present invention, the term "C1-C6 alkoxy" refers to a group obtained by connecting the above C1-C6 alkyl to an oxygen atom. As C1-C6 alkoxy, mention may be made of methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, isobutoxy, sec-butoxy, tert-butoxy, n-pentyloxy, sec-pentyloxy, n-hexyloxy and sec-hexyloxy; particularly preferred are methoxy and ethoxy.

[0016] In the present invention, the term "halogen" refers to fluorine, chlorine, bromine and iodine, particularly preferably fluorine, chlorine and bromine.

[0017] In some preferred embodiments of the present invention, in formula (I), R1-R 11 are the same or different and are each independently selected from hydrogen, methyl, ethyl, n-propyl, isopropyl, fluorine, chlorine, bromine, methoxy, ethoxy and nitro. Preferably, R1-R6 are hydrogen, R7 and R 11 are methyl, and R8-R 10 are hydrogen; M is Fe(II).

[0018] In some preferred embodiments of the present invention, in the catalyst composition, based on the total weight of the cyclohexane, the water content is 100 ppm to 500 ppm, preferably 210 ppm to 250 ppm, more preferably 210 ppm to 240 ppm, further preferably 210 ppm to 230 ppm, and still further preferably 220 ppm to 230 ppm.

[0019] The inventors of the present application found in their research that in the specific system of the present invention, a water content within the above specific range is beneficial to obtaining higher catalytic activity and target product yield.

[0020] According to the present invention, the water content of the cyclohexane product used industrially is generally 0 - 20 ppm. The cyclohexane used in the present invention is anhydrous cyclohexane. The water content defined in the present invention is achieved by additionally introducing a certain amount of water.

[0021] In some preferred embodiments of the present invention, in the catalyst composition, based on the total volume of the cyclohexane, the content of the main catalyst is 1 μmol / L to 500 μmol / L, preferably 10 μmol / L to 300 μmol / L, and more preferably 10 μmol / L to 100 μmol / L.

[0022] In some preferred embodiments of the present invention, the molar ratio of aluminum in the alkylaluminum compound to M in the main catalyst is more than 30:1 and less than 900:1, preferably 100:1 to 700:1, and more preferably 148:1 to 196:1.

[0023] In some preferred embodiments of the present invention, the general formula of the alkylaluminum compound is AlR n X m , where each R is independently a straight-chain or branched C1-C8 alkyl group; X is a halogen, preferably chlorine or bromine; n is an integer from 1 to 3, m is an integer from 0 to 2, and m + n equals 3.

[0024] In some preferred embodiments of the present invention, the alkylaluminum compound is selected from at least one of trimethylaluminum, triethylaluminum, tripropylaluminum, triisobutylaluminum, tri-n-hexylaluminum, tri-n-octylaluminum, diethylaluminum chloride, and ethylaluminum dichloride; more preferably triethylaluminum.

[0025] To achieve the second above-mentioned object, the technical solution adopted by the present invention is as follows:

[0026] A method for preparing a catalyst composition according to any one of the above embodiments, comprising:

[0027] Mix the main catalyst, the alkylaluminum compound, the cyclohexane and the water to obtain the catalyst composition.

[0028] In some preferred embodiments of the present invention, the method for preparing the above-mentioned catalyst composition includes: mixing an aqueous cyclohexane solution, a cyclohexane solution containing the main catalyst, and a cyclohexane solution containing the alkylaluminum compound to obtain the catalyst composition.

[0029] In some preferred embodiments of the present invention, the preparation method includes the following steps:

[0030] 1) Mix water and cyclohexane to obtain an aqueous cyclohexane solution;

[0031] 2) Add the cyclohexane solution containing the main catalyst to the aqueous cyclohexane solution;

[0032] 3) Add the cyclohexane solution containing the alkylaluminum compound to the solution obtained in step 2) to obtain the catalyst composition.

[0033] In some preferred embodiments of the present invention, in the cyclohexane solution containing the main catalyst, the concentration of the main catalyst is 0.1 μmol / mL to 50 μmol / mL, preferably 1 μmol / mL to 10 μmol / mL; and / or in the cyclohexane solution containing the alkylaluminum compound, the concentration of the alkylaluminum compound is 100 μmol / mL to 1500 μmol / mL, preferably 500 μmol / mL to 1000 μmol / mL.

[0034] In some preferred embodiments of the present invention, the volume ratio of the aqueous cyclohexane solution, the cyclohexane solution containing the main catalyst, and the cyclohexane solution containing the alkylaluminum compound is (80 - 99):(0.5 - 10):(0.5 - 10), preferably (80 - 98):(1 - 10):(1 - 10), more preferably (90 - 98):(1 - 5):(1 - 5).

[0035] To achieve the third above-mentioned object, the technical solution adopted by the present invention is as follows:

[0036] Use of a catalyst composition as described above or a catalyst composition prepared according to the above-mentioned preparation method in the field of olefin oligomerization, especially in the field of ethylene oligomerization.

[0037] In some preferred embodiments of the present invention, the conditions for the application include: the temperature is 10°C to 90°C, preferably 40°C to 75°C, more preferably 50°C to 70°C, and further preferably 55°C to 70°C.

[0038] In the prior art, the ethylene oligomerization reaction is usually carried out in the temperature range of 30°C to 40°C. However, the temperature range of 30°C to 40°C is difficult to achieve, and the operation difficulty in industry is relatively large. The present invention can be applied in a higher and more easily achievable temperature range, reducing the operation difficulty in industry. At the same time, since a higher temperature is required, condensed water can be used as the reaction heat removal medium. Compared with the use of chilled water that is necessary to achieve a lower reaction temperature, the energy consumption is reduced, and the industrial application value is significantly improved.

[0039] In some preferred embodiments of the present invention, the conditions of the application include using condensed water as the reaction heat removal medium.

[0040] The beneficial effects of the present invention are at least in the following aspects:

[0041] First, for the catalyst composition of the present invention, when the molar ratio of metallic aluminum in the cocatalyst to the central metal in the main catalyst is 196, the oligomerization and polymerization activity reaches 3.66×10 7 g·mol(Fe) -1 ·h -1 at 40°C, and with the further increase of the reaction temperature, the activity does not decrease significantly.

[0042] Second, when the ethylene oligomerization reaction is carried out using the catalyst composition of the present invention, the product distribution coefficient in the obtained ethylene oligomerization product is above 0.55, and can even reach 0.72.

[0043] Third, when the ethylene oligomerization reaction is carried out using the catalyst composition of the present invention, the yield of the undesired C4 product in the obtained ethylene oligomerization product is low, while the yields of the desired C6-C 10 、C6-C 18 、C6-C 18 linear α-olefin products are high. Specific Embodiments

[0044] The present invention will be described in detail below through examples, but the protection scope of the present invention is not limited to the following description.

[0045] For those conditions not specified in the examples, they are carried out according to conventional conditions or the conditions recommended by the manufacturer. For the reagents or instruments whose manufacturers are not specified, they are all conventional products that can be obtained through commercial channels.

[0046] In the present invention, the product distribution coefficient (k) = ethylene oligomerization chain growth rate / (chain growth rate + chain transfer rate) = C 2n+2 / C 2n .

[0047] In the present invention, the cyclohexane solvent used is anhydrous cyclohexane.

[0048] Example 1

[0049] (1) The reactor is replaced by high-temperature drying, vacuum replacement and other operations to ensure that there is no water and oxygen in the reactor;

[0050] (2) replacing the reactor with ethylene to place the reaction system in an ethylene environment;

[0051] (3) Add water and cyclohexane solvent to a reaction kettle, add 1.37 mL of triethylaluminum cyclohexane solution (the concentration of triethylaluminum is 715 μmol / mL), add 2 mL of 2-formyl-1,10-phenanthroline-2,6-dimethylaniline iron (II) chloride solution (the concentration of 2-formyl-1,10-phenanthroline-2,6-dimethylaniline iron (II) chloride complex is 2.5 μmol / mL), and make the total amount of the composition 100 mL, wherein the weight of cyclohexane is used as the calculation basis, the weight content of water is 225 ppm, and the Al / Fe (molar ratio) is 196. After sufficient stirring, ethylene is introduced to start the polymerization reaction;

[0052] (4) maintaining the ethylene pressure at 1 MPa and the reaction temperature at 60° C. for 30 minutes;

[0053] (5) Stop the reaction, take out a small amount of the reaction product and analyze it by gas chromatography (GC). The specific analysis results are shown in Table 1.

[0054] Example 2

[0055] The only difference from Example 1 is that "the weight content of water is 100 ppm based on the weight of cyclohexane".

[0056] After the reaction was stopped, a small amount of the reaction product was taken out and analyzed by gas chromatography (GC). The specific analysis results are shown in Table 1.

[0057] Example 3

[0058] The only difference from Example 1 is that "the weight content of water is 150 ppm based on the weight of cyclohexane".

[0059] After the reaction was stopped, a small amount of the reaction product was taken out and analyzed by gas chromatography (GC). The specific analysis results are shown in Table 1.

[0060] Example 4

[0061] The only difference from Example 1 is that "the weight content of water is 300 ppm based on the weight of cyclohexane".

[0062] After the reaction stopped, a small amount of the reaction product was taken out and analyzed by gas chromatography (GC). The specific analysis results are shown in Table 1.

[0063] Example 5

[0064] The difference from Example 1 is only that "based on the weight of cyclohexane, the weight content of water is 500 ppm".

[0065] After the reaction stopped, a small amount of the reaction product was taken out and analyzed by gas chromatography (GC). The specific analysis results are shown in Table 1.

[0066] Example 6

[0067] "Iron(II) complex of 2-formyl-1,10-phenanthroline condensed with 2,6-diethylaniline chloride" was used to replace "iron(II) complex of 2-formyl-1,10-phenanthroline condensed with 2,6-dimethylaniline chloride" in Example 1.

[0068] After the reaction stopped, a small amount of the reaction product was taken out and analyzed by gas chromatography (GC). The specific analysis results are shown in Table 1.

[0069] Example 7

[0070] The difference from Example 1 is only that "the reaction temperature is 10 °C".

[0071] After the reaction stopped, a small amount of the reaction product was taken out and analyzed by gas chromatography (GC). The specific analysis results are shown in Table 1.

[0072] Example 8

[0073] The difference from Example 1 is only that "the reaction temperature is 30 °C".

[0074] After the reaction stopped, a small amount of the reaction product was taken out and analyzed by gas chromatography (GC). The specific analysis results are shown in Table 1.

[0075] Example 9

[0076] The difference from Example 1 is only that "the reaction temperature is 40 °C".

[0077] After the reaction stopped, a small amount of the reaction product was taken out and analyzed by gas chromatography (GC). The specific analysis results are shown in Table 1.

[0078] Example 10

[0079] The difference from Example 1 is only that "the reaction temperature is 50 °C".

[0080] After the reaction stopped, a small amount of the reaction product was taken out and analyzed by gas chromatography (GC). The specific analysis results are shown in Table 1.

[0081] Example 11

[0082] It is only different from Example 1 in that "the reaction temperature is 55 °C".

[0083] After the reaction stopped, a small amount of the reaction product was taken out and analyzed by gas chromatography (GC). The specific analysis results are shown in Table 1.

[0084] Example 12

[0085] It is only different from Example 1 in that "the reaction temperature is 70 °C".

[0086] After the reaction stopped, a small amount of the reaction product was taken out and analyzed by gas chromatography (GC). The specific analysis results are shown in Table 1.

[0087] Example 13

[0088] It is only different from Example 1 in that "the reaction temperature is 80 °C".

[0089] After the reaction stopped, a small amount of the reaction product was taken out and analyzed by gas chromatography (GC). The specific analysis results are shown in Table 1.

[0090] Comparative Example 1

[0091] "Toluene" was used to replace "cyclohexane" in Example 1.

[0092] After the reaction stopped, a small amount of the reaction product was taken out and analyzed by gas chromatography (GC). The specific analysis results are shown in Table 1.

[0093] Comparative Example 2

[0094] "Xylene" was used to replace "cyclohexane" in Example 1.

[0095] After the reaction stopped, a small amount of the reaction product was taken out and analyzed by gas chromatography (GC). The specific analysis results are shown in Table 1.

[0096] Comparative Example 3

[0097] "Ethanol" was used to replace "cyclohexane" in Example 1.

[0098] After the reaction stopped, a small amount of the reaction product was taken out and analyzed by gas chromatography (GC). The specific analysis results are shown in Table 1.

[0099] Comparative Example 4

[0100] "Methylcyclohexane" was used to replace "cyclohexane" in Example 1.

[0101] After the reaction stopped, a small amount of the reaction product was taken out and analyzed by gas chromatography (GC). The specific analysis results are shown in Table 1.

[0102] Comparative Example 5

[0103] "Methylaluminoxane" was used to replace "triethylaluminum" in Example 1.

[0104] After the reaction stopped, a small amount of the reaction product was taken out and analyzed by gas chromatography (GC). The specific analysis results are shown in Table 1.

[0105] Comparative Example 6

[0106] "Methylaluminoxane" was used to replace "triethylaluminum" in Example 1, and the Al / Fe (molar ratio) was adjusted to 1000.

[0107] After the reaction stopped, a small amount of the reaction product was taken out and analyzed by gas chromatography (GC). The specific analysis results are shown in Table 1.

[0108] Table 1

[0109]

[0110]

[0111] Note: In the above table, k refers to the product distribution coefficient.

[0112] As can be seen from the data in Table 1 above,

[0113] First, the catalyst composition provided by the present invention has very high oligomerization reaction activity. When ethylene oligomerization reaction is carried out in the presence of the catalyst composition provided by the present invention, the oligomerization reaction can be rapidly initiated;

[0114] Second, the content of the unwanted C4 impurities in the oligomerization product is less, and the product distribution coefficient is relatively high, indicating that the reaction system initiated by the catalyst composition provided by the present invention operates stably and has good repeatability;

[0115] Third, the catalyst composition provided by the present invention can carry out the reaction at a relatively high reaction temperature. This relatively high reaction temperature is easier to achieve than the reaction temperature of 30°C - 50°C commonly used in the art. And as a result, condensed water can be used as the reaction heat removal medium, which reduces the energy consumption compared with using chilled water as the reaction heat removal medium when the reaction temperature is 30°C - 50°C, and the industrial application value is significantly improved;

[0116] Fourth, as the reaction temperature increases, the catalyst composition provided by the present invention still maintains very high activity, and at a relatively high temperature of 60°C - 70°C, the product distribution coefficient can still reach about 0.7 without a significant decrease.

[0117] It should be noted that the above-described embodiments are only used to explain the present invention and do not constitute any limitation to the present invention. The present invention has been described by referring to typical embodiments, but it should be understood that the words used therein are descriptive and explanatory words rather than limiting words. Modifications can be made to the present invention within the scope of the claims of the present invention as provided, and the present invention can be revised without departing from the scope and spirit of the present invention. Although the present invention described therein relates to specific methods, materials and embodiments, it does not mean that the present invention is limited to the specific examples disclosed therein. On the contrary, the present invention can be extended to all other methods and applications with the same functions.

Claims

1. A catalyst composition for olefin oligomerization, comprising: The main catalyst represented by formula (I), an alkylaluminum compound, cyclohexane, and water In formula (I), R1-R6 are hydrogen, R7 and R 11 are methyl, R8-R 10 are hydrogen; M is Fe(II); In the catalyst composition, based on the total weight of the cyclohexane, the weight content of the water is 210 ppm to 240 ppm.

2. The catalyst composition according to claim 1, wherein In the catalyst composition, based on the total weight of the cyclohexane, the weight content of the water is 210 ppm to 230 ppm.

3. The catalyst composition according to claim 2, wherein In the catalyst composition, based on the total weight of the cyclohexane, the weight content of the water is 220 ppm to 230 ppm.

4. The catalyst composition according to any one of claims 1-3, characterized in that In the catalyst composition, based on the total volume of the cyclohexane, the content of the main catalyst is 1 μmol / L to 500 μmol / L.

5. The catalyst composition according to claim 4, characterized in that, In the catalyst composition, based on the total volume of the cyclohexane, the content of the main catalyst is 10 μmol / L to 300 μmol / L.

6. The catalyst composition according to claim 5, characterized in that, In the catalyst composition, based on the total volume of the cyclohexane, the content of the main catalyst is 10 μmol / L to 100 μmol / L.

7. The catalyst composition according to any one of claims 1-3, characterized in that, In the catalyst composition, the molar ratio of aluminum in the alkylaluminum compound to M in the main catalyst is more than 30:1 and less than 900:

1.

8. The catalyst composition according to claim 7, characterized in that, In the catalyst composition, the molar ratio of aluminum in the alkylaluminum compound to M in the main catalyst is 100:1 to 700:

1.

9. The catalyst composition according to claim 8, wherein In the catalyst composition, the molar ratio of aluminum in the alkylaluminum compound to M in the main catalyst is 148:1 to 196:

1.

10. The catalyst composition according to any one of claims 1-3, characterized in that, The general formula of the alkylaluminum compound is AlR n X m , where each R is independently a C1-C8 straight-chain alkyl group or a C3-C8 branched-chain alkyl group; X is a halogen; n is an integer from 1 to 3, m is an integer from 0 to 2, and m + n equals 3.

11. The catalyst composition according to claim 10, wherein X is selected from chlorine or bromine.

12. The catalyst composition according to claim 10, wherein The alkylaluminum compound is selected from at least one of trimethylaluminum, triethylaluminum, tripropylaluminum, triisobutylaluminum, tri-n-hexylaluminum, tri-n-octylaluminum, diethylaluminum chloride, and ethylaluminum dichloride.

13. The catalyst composition according to claim 12, wherein The alkylaluminum compound is selected from triethylaluminum.

14. A method for preparing the catalyst composition according to any one of claims 1-13, comprising: Mixing the main catalyst, the alkylaluminum compound, the cyclohexane, and the water to obtain the catalyst composition.

15. The preparation method according to claim 14, wherein Mixing a cyclohexane solution containing water, a cyclohexane solution containing the main catalyst, and a cyclohexane solution containing the alkylaluminum compound to obtain the catalyst composition.

16. The preparation method according to claim 15, characterized in that, The preparation method includes the following steps: 1) Mixing water and cyclohexane to obtain a cyclohexane solution containing water; 2) Adding the cyclohexane solution containing the main catalyst to the cyclohexane solution containing water; 3) Adding the cyclohexane solution containing the alkylaluminum compound to the solution obtained in step 2) to obtain the catalyst composition.

17. The preparation method according to any one of claims 14-16, characterized in that, In the cyclohexane solution containing the main catalyst, the concentration of the main catalyst is 0.1 μmol / mL to 50 μmol / mL; and / or in the cyclohexane solution containing the alkylaluminum compound, the concentration of the alkylaluminum compound is 100 μmol / mL to 1500 μmol / mL.

18. The preparation method according to claim 17, wherein, In the cyclohexane solution containing the main catalyst, the concentration of the main catalyst is 1 μmol / mL to 10 μmol / mL; and / or in the cyclohexane solution containing the alkylaluminum compound, the concentration of the alkylaluminum compound is 500 μmol / mL to 1000 μmol / mL.

19. The preparation method according to any one of claims 14-16, characterized in that, The volume ratio of the water-containing cyclohexane solution, the cyclohexane solution containing the main catalyst, and the cyclohexane solution containing the alkylaluminum compound is (80 - 99):(0.5 - 10):(0.5 - 10).

20. The preparation method according to claim 19, wherein The volume ratio of the water-containing cyclohexane solution, the cyclohexane solution containing the main catalyst, and the cyclohexane solution containing the alkylaluminum compound is (80 - 98):(1 - 10):(1 - 10).

21. The preparation method according to claim 20, characterized in that, The volume ratio of the water-containing cyclohexane solution, the cyclohexane solution containing the main catalyst, and the cyclohexane solution containing the alkylaluminum compound is (90 - 98):(1 - 5):(1 - 5).

22. Use of the catalyst composition according to any one of claims 1 - 13 or the catalyst composition prepared by the preparation method according to any one of claims 14 - 21 in the field of olefin oligomerization.

23. The application according to claim 22, characterized in that, The use is in the field of ethylene oligomerization.

24. The application according to claim 22 or 23, characterized in that, The conditions of the use include: the temperature is 10°C to 90°C.

25. The application according to claim 24, wherein The conditions of the use include: the temperature is 40°C to 75°C.

26. The application according to claim 25, wherein The conditions of the use include: the temperature is 50°C to 70°C.

27. The application according to claim 26, characterized in that, The conditions of the use include: the temperature is 55°C to 70°C.

Images