A fluorine-containing ligand, a fluorine-containing metal complex, and an ethylene oligomerization catalyst composition

Abstract

The present application relates to fluorine-containing ligand, fluorine-containing metal complex and ethylene oligomerization catalyst composition, wherein the structure of the fluorine-containing ligand is shown as formula (I), in formula (I), R 1 And R 2 Same or different, each independently selected from hydrogen, halogen, substituted or unsubstituted alkyl, substituted or unsubstituted cycloalkyl, substituted or unsubstituted aryl, substituted or unsubstituted alkylaryl and substituted or unsubstituted arylalkyl;R1-R 18 Each independently selected from hydrogen, cyano, substituted or unsubstituted alkyl and substituted or unsubstituted alkoxy. In the present application, the catalyst can effectively catalyze ethylene trimerization and tetramerization reaction, initiate rapidly, run smoothly, have good repeatability, strong practicability and wide industrialization prospect.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of ethylene oligomerization, and also to the field of ethylene trimerization and tetramerization, and in particular to a fluorine-containing ligand, a fluorine-containing metal complex and a fluorine-containing base ethylene oligomerization catalyst composition and application. BACKGROUND

[0002] Alpha-olefins are important organic raw materials and chemical intermediates, mainly used in the production of high-quality polyethylene (PE), lubricating oil base oil, plasticizer, detergent, etc. Among them, 1-hexene or 1-octene has a wide range of uses, and linear low-density polyethylene (LLDPE) produced by copolymerization of 1-hexene or 1-octene with ethylene can significantly improve the performance of PE, especially the mechanical properties, optical properties, and tear strength and impact strength of polyethylene, and the product is very suitable for packaging film and greenhouse, shed and other agricultural mulching film fields. The polyolefin plastomer and polyolefin elastomer produced by copolymerization of 1-octene with ethylene have a large market consumption and demand. With the continuous development of the polyolefin industry, the demand for alpha-olefins is growing rapidly worldwide.

[0003] Ethylene oligomerization is one of the most important reactions in the olefin polymerization industry. Through oligomerization, inexpensive small molecule ethylene can be converted into high value-added products, i.e. alpha-olefins of different chain lengths. Since the 1970s, transition metal complex catalyzed olefin polymerization and oligomerization has gradually attracted the attention of scientists, and people have begun to strive to develop new catalysts and improve existing catalysts to improve the activity of the catalysts and the selectivity of the catalyzed products. In the numerous explorations, the earliest and fastest developing and more focused is the nickel-based cationic catalyst system, such as the U.S. patents US3686351 and US3676523, and the Shell Corporation SHOP process based on the patent technology. In the Shell Corporation SHOP process, O-P bridged ligands are involved, but the catalyst contains toxic organophosphorus groups, and the synthesis steps are complex and the stability is poor. Later, O-O, P-N, P-P and N-N type coordination nickel catalysts and many other patents were developed, such as JP11060627, WO9923096, WO991550, CN1401666, CN1769270, etc. However, the catalysts obtained from the above patents generally have the disadvantage of relatively complex preparation method.

[0004] Patent WO04056478 of Sasol Company discloses PNP backbone type catalyst, in ethylene tetramerization reaction, C8 component selectivity is about 66wt%, C6 component selectivity is about 21wt%, wherein 1-hexene content in C6 component is only 82%, total selectivity of 1-hexene and 1-octene is about 84%. PCCP symmetrical backbone type catalyst is disclosed in US20100137669 patent, in ethylene tetramerization reaction, the catalyst is more stable than PNP system, total selectivity of 1-hexene and 1-octene is not more than 85%

[0005] In the above reaction system, although the by-products such as cyclic olefins and cyclized products existing in the C6 product can be removed by separation and purification, etc., it is not conducive to the economy of the whole process. SUMMARY

[0006] In view of the deficiencies of the prior art, the inventors of the present application have made in-depth research on the phosphorus-containing catalysts, and found a fluorine-containing ethylene oligomerization catalyst composition, which comprises a catalyst ligand shown in formula I, a transition metal compound and an aluminum-containing cocatalyst. The catalyst ligand is a carbon-based bridged diphosphine structure, and contains an ortho halogen substituent on the aromatic ring, which is novel in structure, simple to prepare and low in cost. The catalyst composition described in the present application can effectively catalyze the ethylene oligomerization reaction, especially the ethylene trimerization and tetramerization reaction, and has a catalytic activity of more than 0.7×10 8 g·mol(Cr) -1 ·h -1 , and up to 3.6×10 8 g·mol(Cr) -1 ·h -1 Under different conditions, the total selectivity of 1-hexene and 1-octene is more than 91wt%, and up to more than 95wt%; and in the C6 product, the content of 1-hexene is more than 92%, and the by-products such as cyclic olefins and cyclized products are significantly reduced. Therefore, the catalyst composition described in the present application has high catalytic activity, high selectivity and other characteristics, and has good industrial application prospect and economic value.

[0007] According to a first aspect of the present application, the present application provides a fluorine-containing ligand, which has a structure as shown in formula (I),

[0008]

[0009] In formula (I), R 1 and R 2 are the same or different, and each is independently selected from hydrogen, halogen, substituted or unsubstituted alkyl, substituted or unsubstituted cycloalkyl, substituted or unsubstituted aryl, substituted or unsubstituted alkylaryl and substituted or unsubstituted arylalkyl;

[0010] R1-R5are each independently selected from the group consisting of hydrogen, cyano, substituted or unsubstituted alkyl and substituted or unsubstituted alkoxy. 18 R1-R5are each independently selected from the group consisting of hydrogen, cyano, substituted or unsubstituted alkyl and substituted or unsubstituted alkoxy.

[0011] According to some embodiments of the present application, R1-R5are each independently selected from the group consisting of hydrogen, cyano, substituted or unsubstituted C1-C10alkyl and substituted or unsubstituted C1-C10alkoxy. 1 R1-R5are each independently selected from the group consisting of hydrogen, cyano, substituted or unsubstituted alkyl and substituted or unsubstituted alkoxy. 2 R1-R5are each independently selected from the group consisting of hydrogen, cyano, substituted or unsubstituted alkyl and substituted or unsubstituted alkoxy.

[0012] According to some embodiments of the present application, R1-R5are each independently selected from the group consisting of hydrogen, cyano, substituted or unsubstituted C1-C6alkyl and substituted or unsubstituted C1-C6alkoxy. 1 R1-R5are each independently selected from the group consisting of hydrogen, cyano, substituted or unsubstituted alkyl and substituted or unsubstituted alkoxy. 2 R1-R5are each independently selected from the group consisting of hydrogen, cyano, substituted or unsubstituted alkyl and substituted or unsubstituted alkoxy.

[0013] According to some embodiments of the present application, R1-R5are each independently selected from the group consisting of hydrogen, cyano, substituted or unsubstituted C1-C6alkyl and substituted or unsubstituted C1-C6alkoxy. 1 R1-R5are each independently selected from the group consisting of hydrogen, cyano, substituted or unsubstituted alkyl and substituted or unsubstituted alkoxy. 2 R1-R5are each independently selected from the group consisting of hydrogen, cyano, substituted or unsubstituted alkyl and substituted or unsubstituted alkoxy.

[0014] According to some embodiments of the present application, R1-R5are each independently selected from the group consisting of hydrogen, cyano, substituted or unsubstituted C1-C10alkyl and substituted or unsubstituted C1-C10alkoxy. 18 R1-R5are each independently selected from the group consisting of hydrogen, cyano, substituted or unsubstituted alkyl and substituted or unsubstituted alkoxy.

[0015] According to some embodiments of the present application, R1-R5are each independently selected from the group consisting of hydrogen, cyano, substituted or unsubstituted C1-C10alkyl and substituted or unsubstituted C1-C10alkoxy. 18 R1-R5are each independently selected from the group consisting of hydrogen, cyano, substituted or unsubstituted alkyl and substituted or unsubstituted alkoxy.

[0016] According to some embodiments of the present application, R1-R5are the same, for example, each are hydrogen, C1-C5alkyl or C1-C5alkoxy.

[0017] According to some embodiments of the application, R1-R5 are the same, for example, all are hydrogen, methyl, ethyl, n-propyl, i-propyl, n-butyl, t-butyl, i-butyl, n-pentyl, i-pentyl, methoxy, ethoxy, n-propoxy, i-propoxy, n-butoxy, t-butoxy, i-butoxy, n-pentoxy, or i-pentoxy.

[0018] According to some embodiments of the application, R6-R9 are the same, for example, all are hydrogen, C1-C5 alkyl, or C1-C5 alkoxy.

[0019] According to some embodiments of the application, R6-R9 are the same, for example, all are hydrogen, methyl, ethyl, n-propyl, i-propyl, n-butyl, t-butyl, i-butyl, n-pentyl, i-pentyl, methoxy, ethoxy, n-propoxy, i-propoxy, n-butoxy, t-butoxy, i-butoxy, n-pentoxy, or i-pentoxy.

[0020] According to some embodiments of the application, R 10 -R 14 are the same, for example, all are hydrogen, C1-C5 alkyl, or C1-C5 alkoxy.

[0021] According to some embodiments of the application, R 10 -R 14 are the same, for example, all are hydrogen, methyl, ethyl, n-propyl, i-propyl, n-butyl, t-butyl, i-butyl, n-pentyl, i-pentyl, methoxy, ethoxy, n-propoxy, i-propoxy, n-butoxy, t-butoxy, i-butoxy, n-pentoxy, or i-pentoxy.

[0022] According to some embodiments of the application, R 15 -R 18 are the same, for example, all are hydrogen, C1-C5 alkyl, or C1-C5 alkoxy.

[0023] According to some embodiments of the application, R 15 -R 18 are the same, for example, all are hydrogen, methyl, ethyl, n-propyl, i-propyl, n-butyl, t-butyl, i-butyl, n-pentyl, i-pentyl, methoxy, ethoxy, n-propoxy, i-propoxy, n-butoxy, t-butoxy, i-butoxy, n-pentoxy, or i-pentoxy.

[0024] According to some embodiments of the application, the substituents are selected from cyano, C1-C10 alkyl, or C1-C10 alkoxy.

[0025] According to some embodiments of the present application, the substituents are selected from the group consisting of cyano, methyl, ethyl, n-propyl, iso-propyl, n-butyl, t-butyl, iso-butyl, n-pentyl, iso-pentyl, n-hexyl, n-heptyl, methoxy, ethoxy, n-propoxy, iso-propoxy, n-butoxy, t-butoxy, iso-butoxy, n-pentoxy, iso-pentoxy, n-hexoxy and n-heptoxy.

[0026] In some preferred embodiments of the present application, R 1 and R 2 are each hydrogen, and R1-R 18 are each hydrogen.

[0027] In some preferred embodiments of the present application, R 1 and R 2 are each C1-C4 linear alkyl, such as methyl, and R1-R 18 are each hydrogen.

[0028] In some preferred embodiments of the present application, R 1 is C3-C6 branched alkyl, such as t-butyl, and R 2 is hydrogen, and R1-R 18 are each hydrogen.

[0029] In some preferred embodiments of the present application, R 1 is C4-C8 cyclic alkyl, such as cyclohexyl, and R 2 is hydrogen, and R1-R 18 are each hydrogen.

[0030] In some preferred embodiments of the present application, R 1 is C6-C20 aryl, such as phenyl, and R 2 is hydrogen, and R1-R 18 are each hydrogen.

[0031] According to a second aspect of the present application, the present application provides a fluorine-containing metal complex having a structure represented by formula (II),

[0032]

[0033] In formula (II), R 3 and R 4 are the same or different, and each is independently selected from the group consisting of hydrogen, halogen, substituted or unsubstituted alkyl, substituted or unsubstituted cyclic alkyl, substituted or unsubstituted aryl, substituted or unsubstituted alkylaryl and substituted or unsubstituted arylalkyl; R 19 -R 36each independently selected from the group consisting of hydrogen, cyano, substituted or unsubstituted alkyl, and substituted or unsubstituted alkoxy; M is selected from transition metal elements; X is selected from halogen; n represents the number satisfying the valence state of M, for example, 1, 2, or 3.

[0034] According to some embodiments of the present application, the R 3 and R 4 are the same or different, each independently selected from the group consisting of hydrogen, fluorine, chlorine, bromine, iodine, substituted or unsubstituted C1-C10 alkyl, substituted or unsubstituted C3-C20 cycloalkyl, substituted or unsubstituted C6-C30 aryl, substituted or unsubstituted C7-C30 alkylaryl, and substituted or unsubstituted C7-C30 aralkyl.

[0035] According to some embodiments of the present application, the R 3 and R 4 are the same or different, each independently selected from the group consisting of hydrogen, fluorine, chlorine, bromine, iodine, substituted or unsubstituted C1-C6 alkyl, substituted or unsubstituted C3-C10 cycloalkyl, substituted or unsubstituted C6-C20 aryl, substituted or unsubstituted C7-C20 alkylaryl, and substituted or unsubstituted C7-C20 aralkyl.

[0036] According to some embodiments of the present application, the R 3 and R 4 are the same or different, each independently selected from the group consisting of methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl, t-butyl, cyclopropyl, cyclopentyl, cyclohexyl, and substituted or unsubstituted phenyl.

[0037] According to some embodiments of the present application, R 19 -R 36 are each independently selected from the group consisting of hydrogen, cyano, substituted or unsubstituted C1-C10 alkyl, and substituted or unsubstituted C1-C10 alkoxy.

[0038] According to some embodiments of the present application, R 19 -R 36 are each independently selected from the group consisting of hydrogen, cyano, methyl, ethyl, n-propyl, i-propyl, n-butyl, t-butyl, i-butyl, n-pentyl, i-pentyl, n-hexyl, n-heptyl, methoxy, ethoxy, n-propoxy, i-propoxy, n-butoxy, t-butoxy, i-butoxy, n-pentoxy, i-pentoxy, n-hexoxy, and n-heptoxy.

[0039] According to some embodiments of the present application, R 19 -R 23 are the same, for example, both are hydrogen, C1-C5 alkyl, or C1-C5 alkoxy.

[0040] According to some embodiments of the application, R 19 -R 23 are identical, for example, both are hydrogen, methyl, ethyl, n-propyl, i-propyl, n-butyl, t-butyl, i-butyl, n-pentyl, i-pentyl, methoxy, ethoxy, n-propoxy, i-propoxy, n-butoxy, t-butoxy, i-butoxy, n-pentoxy or i-pentoxy.

[0041] According to some embodiments of the application, R 24 -R 27 are identical, for example, both are hydrogen, C1-C5-alkyl or C1-C5-alkoxy.

[0042] According to some embodiments of the application, R 24 -R 27 are identical, for example, both are hydrogen, methyl, ethyl, n-propyl, i-propyl, n-butyl, t-butyl, i-butyl, n-pentyl, i-pentyl, methoxy, ethoxy, n-propoxy, i-propoxy, n-butoxy, t-butoxy, i-butoxy, n-pentoxy or i-pentoxy.

[0043] According to some embodiments of the application, R 28 -R 32 are identical, for example, both are hydrogen, C1-C5-alkyl or C1-C5-alkoxy.

[0044] According to some embodiments of the application, R 28 -R 32 are identical, for example, both are hydrogen, methyl, ethyl, n-propyl, i-propyl, n-butyl, t-butyl, i-butyl, n-pentyl, i-pentyl, methoxy, ethoxy, n-propoxy, i-propoxy, n-butoxy, t-butoxy, i-butoxy, n-pentoxy or i-pentoxy.

[0045] According to some embodiments of the application, R 33 -R 36 are identical, for example, both are hydrogen, C1-C5-alkyl or C1-C5-alkoxy.

[0046] According to some embodiments of the application, R 33 -R 36 are identical, for example, both are hydrogen, methyl, ethyl, n-propyl, i-propyl, n-butyl, t-butyl, i-butyl, n-pentyl, i-pentyl, methoxy, ethoxy, n-propoxy, i-propoxy, n-butoxy, t-butoxy, i-butoxy, n-pentoxy or i-pentoxy.

[0047] According to some embodiments of the application, the substituents are selected from the group consisting of cyano, C1-C10-alkyl or C1-C10-alkoxy.

[0048] According to some embodiments of the present application, the substituents are selected from the group consisting of cyano, methyl, ethyl, n-propyl, iso-propyl, n-butyl, t-butyl, iso-butyl, n-pentyl, iso-pentyl, n-hexyl, n-heptyl, methoxy, ethoxy, n-propoxy, iso-propoxy, n-butoxy, t-butoxy, iso-butoxy, n-pentoxy, iso-pentoxy, n-hexoxy and n-heptoxy.

[0049] According to some embodiments of the present application, the transition metal is selected from the group consisting of chromium, molybdenum, iron, titanium, zirconium and nickel.

[0050] According to some embodiments of the present application, the halogen is selected from the group consisting of fluorine, chlorine, bromine and iodine.

[0051] In some preferred embodiments of the present application, R 3 and R 4 are both hydrogen, R 19 is -R 36 is hydrogen, M is Cr, X is Cl and n is 3.

[0052] In some preferred embodiments of the present application, R 3 and R 4 are both C1-C4 linear alkyl, e.g. methyl, R 19 is -R 36 is hydrogen, M is Cr, X is Cl and n is 3.

[0053] In some preferred embodiments of the present application, R 3 is C3-C6 branched alkyl, e.g. t-butyl, R 4 is hydrogen, R 19 is -R 36 is hydrogen, M is Cr, X is Cl and n is 3.

[0054] In some preferred embodiments of the present application, R 3 is C4-C8 cyclic alkyl, e.g. cyclohexyl, R 4 is hydrogen, R 19 is -R 36 is hydrogen, M is Cr, X is Cl and n is 3.

[0055] In some preferred embodiments of the present application, R 3 is C6-C20 aryl, e.g. phenyl, R 4 is hydrogen, R 19 is -R 36 is hydrogen, M is Cr, X is Cl and n is 3.

[0056] According to a third aspect of the present application, the present application provides an ethylene oligomerization catalyst composition comprising the fluorine-containing ligand, the transition metal compound and the aluminum-containing compound according to the first aspect.

[0057] According to some embodiments of the present application, the transition metal compound is selected from one or more of chromium compounds, molybdenum compounds, iron compounds, titanium compounds, zirconium compounds and nickel compounds, preferably selected from one or more of chromium acetylacetonate, chromium iso-octoate, tris(tetrahydrofuran)trichlorochromium and bis(tetrahydrofuran)dichlorochromium.

[0058] According to some embodiments of the present application, the molar ratio of the catalyst ligand, the transition metal compound and the aluminum-containing cocatalyst is 1 : (0.1-10) : (1-1000), preferably 1 : (0.25-2) : (10-700), more preferably 1 : (0.5-2) : (100-500).

[0059] According to some embodiments of the present application, the molar ratio of the catalyst ligand and the transition metal compound is 1 : (0.1-10), for example 1 : 0.2, 1 : 0.3, 1 : 0.4, 1 : 0.7, 1 : 1.0, 1 : 1.5, 1 : 3, 1 : 5, 1 : 7, 1 : 9 and any value therebetween.

[0060] According to some embodiments of the present application, the molar ratio of the catalyst ligand and the transition metal compound is 1 : (0.25-2).

[0061] According to some embodiments of the present application, the molar ratio of the catalyst ligand and the transition metal compound is 1 : (0.5-2).

[0062] According to some embodiments of the present application, the molar ratio of the catalyst ligand and the aluminum-containing compound is 1 : (1-1000), for example 1 : 1, 1 : 10, 1 : 50, 1 : 100, 1 : 50, 1 : 200, 1 : 250, 1 : 300, 1 : 350, 1 : 400, 1 : 450, 1 : 500, 1 : 550, 1 : 600, 1 : 650, 1 : 700, 1 : 750, 1 : 800, 1 : 850, 1 : 900, 1 : 950, 1 : 1000 and any value therebetween.

[0063] According to some embodiments of the present application, the molar ratio of the catalyst ligand and the aluminum-containing compound is 1 : (10-700).

[0064] In some preferred embodiments of the present application, the molar ratio of the catalyst ligand and the aluminum-containing compound is 1 : (100-500).

[0065] In some embodiments of the present application, the aluminum-containing compound can be an organic aluminum compound commonly used in the art, which can be selected from at least one of an alkyl aluminum compound, an alkoxy aluminum compound and a chlorinated alkyl aluminum compound.

[0066] According to some embodiments of the present application, the aluminum-containing co-catalyst is selected from one or more of methylaluminoxane, trimethylaluminum, triethylaluminum, triisobutylaluminum, tri-n-hexylaluminum, tri-n-octylaluminum, diethylaluminum chloride, ethylaluminum dichloride, ethylaluminoxane and modified methylaluminoxane.

[0067] and / or the aluminum-containing compound is selected from an organoaluminum compound, preferably from one or more of an alkylaluminum compound, an alkoxyaluminum compound and a chlorinated alkylaluminum compound, more preferably from one or more of methylaluminoxane, trimethylaluminum, triethylaluminum, triisobutylaluminum, tri-n-hexylaluminum, tri-n-octylaluminum, diethylaluminum chloride, ethylaluminum dichloride, ethylaluminoxane and modified methylaluminoxane

[0068] According to a fourth aspect of the present application, the present application provides an ethylene oligomerization catalyst composition comprising the metal complex of the second aspect and an aluminum-containing compound.

[0069] In some embodiments of the present application, the aluminum-containing compound can be an organoaluminum compound commonly used in the art, which can be selected from at least one of an alkylaluminum compound, an alkoxyaluminum compound and a chlorinated alkylaluminum compound.

[0070] According to some embodiments of the present application, the aluminum-containing co-catalyst is selected from one or more of methylaluminoxane, trimethylaluminum, triethylaluminum, triisobutylaluminum, tri-n-hexylaluminum, tri-n-octylaluminum, diethylaluminum chloride, ethylaluminum dichloride, ethylaluminoxane and modified methylaluminoxane.

[0071] According to some embodiments of the present application, the molar ratio of the metal complex and the aluminum-containing compound is 1:(1-1000), such as 1:1, 1:10, 1:50, 1:100, 1:50, 1:200, 1:250, 1:300, 1:350, 1:400, 1:450, 1:500, 1:550, 1:600, 1:650, 1:700, 1:750, 1:800, 1:850, 1:900, 1:950, 1:1000 and any value therebetween.

[0072] According to some embodiments of the present application, the molar ratio of the metal complex and the aluminum-containing compound is 1:(10-700).

[0073] In some preferred embodiments of the present application, the molar ratio of the metal complex and the aluminum-containing compound is 1:(100-500).

[0074] According to a fifth aspect of the present application, the present application provides an ethylene oligomerization method, which comprises carrying out an ethylene oligomerization reaction, especially an ethylene trimerization and tetramerization reaction, in an organic solvent in the presence of the catalyst composition according to the third or fourth aspect of the present application.

[0075] According to some embodiments of the present application, in the above reaction, the metal complex and the aluminum-containing compound in the catalyst composition can be mixed in advance and then added together into the reaction system, or the metal complex and the aluminum-containing compound can be added into the reaction system separately.

[0076] According to some embodiments of the present application, the organic solvent is an organic solvent commonly used in polymerization reactions, comprising aliphatic hydrocarbon compounds and / or aromatic hydrocarbon compounds.

[0077] According to some embodiments of the present application, the aliphatic hydrocarbon compounds are selected from at least one of the following compounds: straight-chain alkanes, branched alkanes and cycloalkanes.

[0078] According to some embodiments of the present application, the aliphatic hydrocarbon compounds are selected from at least one of the following compounds: pentane, heptane, hexane, cyclohexane and methylcyclohexane.

[0079] According to some embodiments of the present application, the aromatic hydrocarbon compounds are preferably selected from at least one of the following compounds: benzene, toluene, xylene, monochlorobenzene, dichlorobenzene, trichlorobenzene, monochlorotoluene and derivatives thereof.

[0080] According to some embodiments of the present application, the reaction temperature of the reaction is 0-200℃, for example 0℃, 5℃, 10℃, 20℃, 30℃, 35℃, 40℃, 45℃, 50℃, 55℃, 60℃, 65℃, 70℃, 75℃, 80℃, 85℃, 90℃, 100℃, 110℃, 120℃, 130℃, 140℃, 150℃, 160℃, 170℃, 180℃, 190℃, 200℃ and any value therebetween,

[0081] According to some embodiments of the present application, the reaction temperature of the reaction is 0-100℃.

[0082] In some preferred embodiments of the present application, the reaction temperature of the reaction is 30-90℃.

[0083] According to some embodiments of the present application, the pressure of the reaction is 0.1-20 MPa, for example 0.1 MPa, 0.5 MPa, 1.0 MPa, 1.5 MPa, 2.0 MPa, 2.5 MPa, 3.0 MPa, 3.5 MPa, 4.0 MPa, 4.5 MPa, 5.0 MPa, 6.0 MPa, 7.0 MPa, 8.0 MPa, 9.0 MPa, 10 MPa, 11 MPa, 12 MPa, 13 MPa, 14 MPa, 15 MPa, 16 MPa, 17 MPa, 18 MPa, 19 MPa, 20 MPa and any value therebetween.

[0084] According to some embodiments of the present application, the pressure of the reaction is 0.5-5 MPa.

[0085] In some preferred embodiments of the present application, the pressure of the reaction is 2.0-5.0 MPa.

[0086] According to some embodiments of the present application, the concentration of the catalyst composition is 1-20 μmol / L of transition metal, based on the volume of the organic solvent.

[0087] In some embodiments of the present application, the reaction conditions are as follows: ethylene, organic solvent and the catalyst composition are added into a reactor, and then reacted under the conditions of ethylene pressure of 0.1-20.0 MPa, reaction temperature of 0-200 ℃, and catalyst concentration of 1-20 μmol Cr / L. After the reaction, the products in gas and liquid phases are taken for chromatographic analysis after cooling to room temperature.

[0088] Advantages of the present application:

[0089] In the present application, the catalyst ligand in the catalyst composition is a carbon-based bridged diphosphine type structure, which is simple to prepare and has low cost.

[0090] The catalyst composition of the present application can effectively catalyze the oligomerization of ethylene, especially the trimerization and tetramerization of ethylene, and has high catalyst activity and good product selectivity. Moreover, the by-products such as cyclic olefins and cyclic compounds in the C6 product are significantly reduced.

[0091] The catalyst composition of the present application has high catalytic activity and selectivity, and has good industrial application prospect and economic value. DETAILED DESCRIPTION

[0092] The following examples are only used to illustrate the present application in detail, but it should be understood that the scope of the present application is not limited to these examples.

[0093] In embodiments of the present invention, nuclear magnetic resonance (NMR) is performed using a Bruker AV400 NMR spectrometer; gas chromatography (GC) is performed using a HP 5890 chromatograph.

[0094] The detection conditions for nuclear magnetic resonance were: deuterated chloroform as solvent, and testing at room temperature.

[0095] The gas chromatography detection conditions were as follows: SE-54 column, high-purity nitrogen carrier gas, FID detector; and two-stage temperature programming was used for column temperature.

[0096] In this invention, t Bu is schottinki. i Pr stands for isopropyl, Cy for cyclohexyl, Ph for phenyl, Me for methyl, THF for tetrahydrofuran, and acac for acetylacetone.

[0097] Fluorine-containing ligands, the structure of which is shown in formula (I),

[0098]

[0099] Fluorine-containing metal complexes, the structures of which are shown in formula (II),

[0100]

[0101] Synthesis example

[0102] Synthesis Example 1: Fluorine-containing ligand I 1 (In formula (I), R) 1 =t-Bu,R 2 =H,R1-R 18 Preparation of (all hydrogen)

[0103] Ligand I 1 The structure is shown in the formula below. The specific preparation method is as follows: Methylsulfonyl chloride (27.6 mmol) was dissolved in 5 mL of dichloromethane. At 0 °C, a mixed solution of triethylamine (2 mL) and 3,3-dimethyl-1,2-butanediol (13.2 mmol) in dichloromethane was slowly added dropwise. After reacting for 1 hour, the mixture was brought to room temperature and stirred for another 2 hours. After the reaction was complete, 1 M hydrochloric acid aqueous solution was added. The aqueous phase was extracted three times with dichloromethane. The combined organic phases were washed with saturated NaHCO3 and saturated brine, dried over anhydrous Na2SO4, and the solvent was evaporated. After dissolving in 5 mL of THF, a 5 mL solution of HP(2-F-Ph)Ph (CAS No.: 2375444-09-8, 5 mmol) in THF was slowly added dropwise at -78 °C. After 10 min, n-butyllithium (5 mmol) was slowly added, stirred for half an hour, brought to room temperature, and reacted overnight. After the reaction was complete, the solvent was dried, and an appropriate amount of water was added. A large amount of precipitate formed, which was then filtered. The precipitate can be further purified using a short silica gel column to obtain bisphosphine ligand I.1 in 55% yield. 1 H NMR (400 MHz, CDC13): δ = 7.4-7.0 (m, 14H), 2.3-2.2 (m, 1H), 2.0-1.9 (m, 2H), 1.1 (s, 9H).

[0104]

[0105] Synthesis of Ligand I 2 -I 5 Preparation of Ligand I

[0106] Ligand I 2 The structure of Ligand I is shown below, and is prepared in the same manner as Ligand I 1 except that 3,3-dimethyl-1,2-butanediol is replaced by ethylene glycol, 1 H NMR (400 MHz, CDC13): δ = 7.3-6.9 (m, 14H), 1.6 (m, 4H).

[0107]

[0108] Ligand I 3 The structure of Ligand I is shown below, and is prepared in the same manner as Ligand I 1 except that 3,3-dimethyl-1,2-butanediol is replaced by CyCHOHCH2OH, 1 H NMR (400 MHz, CDC13): δ = 7.4-7.0 (m, 14H), 2.4-2.3 (m, 1H), 2.0-1.8 (m, 2H), 1.8-1.7 (m, 1H), 1.6-1.1 (m, 10H).

[0109]

[0110] Ligand I 4 The structure of Ligand I is shown below, and is prepared in the same manner as Ligand I 1 except that 3,3-dimethyl-1,2-butanediol is replaced by PhCHOHCH2OH, 1 H NMR (400 MHz, CDC13): δ = 7.4-7.0 (m, 19H), 3.3-3.2 (m, 1H), 2.5-2.4 (m, 2H).

[0111]

[0112] Ligand I 5 The structure of Ligand I is shown below, and is prepared in the same manner as Ligand I 1 except that 3,3-dimethyl-1,2-butanediol is replaced by CH3CHOHCH2OH, 1H NMR (400 MHz, CDC13): δ = 7.4-7.0 (m, 14H), 2.4-2.3 (m, 2H), 1.9-1.8 (m, 2H), 1.3 (d, 3H).

[0113]

[0114] Synthesis Example 6

[0115] Metal complex II 1 The structure of the metal complex II is shown in the following formula, and the specific preparation method is as follows: 5 mmol of ligand I 1 and 5 mmol of CrCl3(THF)3 are transferred to a Schlenk tube under nitrogen protection, 50 mL of toluene solution is added, and then the temperature is raised to 80°C and stirred for 8 hours. The reaction liquid is lowered to room temperature, and the filtration is carried out, and the obtained solid is washed with toluene and n-hexane respectively, and vacuum dried to obtain the corresponding metal complex II 1

[0116]

[0117] Synthesis Example 7

[0118] Metal complex II 2 The structure of the metal complex II is shown in the following formula, and the specific preparation method is as follows: 5 mmol of ligand I 5 and 5 mmol of CrCl3(THF)3 are transferred to a Schlenk tube under nitrogen protection, 50 mL of toluene solution is added, and then the temperature is raised to 80°C and stirred for 8 hours. The reaction liquid is lowered to room temperature, and the filtration is carried out, and the obtained solid is washed with toluene and n-hexane respectively, and vacuum dried to obtain the corresponding metal complex II 1

[0119]

[0120] Example 1 uses catalyst ligand I 1 (R 1 = t-Bu, R 2 = H) to carry out ethylene oligomerization reaction

[0121] A 300 mL stainless steel polymerization kettle is used. The autoclave is heated to 80°C, vacuumed and replaced with nitrogen several times, then filled with ethylene after replacement, and then lowered to the set temperature. Then add methylcyclohexane at 40°C, and add 0.5 μmol of tris (tetrahydrofuran) chromium chloride and catalyst ligand I 1 and cocatalyst modified methylaluminoxane (MMAO), the total volume of the mixed solution is 100 mL, and the molar ratio of acetylacetone chromium, ligand compound and cocatalyst is 1:2:500, that is, ligand compound I 1The amount added was 1.0 μmol, the amount of MMAO added was 250 μmol, the reaction pressure was controlled at 3 MPa, and ethylene was introduced to carry out the ethylene oligomerization reaction.

[0122] Half an hour later, the reaction was complete. The system was cooled to room temperature, and the gaseous product was collected in a gas metering vessel, while the liquid product was collected in an Erlenmeyer flask. 1 mL of ethanol was added as a terminator to terminate the reaction. The gas and liquid products were then analyzed by gas chromatography (using a HP 5890 chromatograph). The results are shown in Table 1.

[0123] Example 2 uses catalyst ligand I 2 (R 1 =R 2 =H) to carry out ethylene oligomerization reaction

[0124] Same as Example 1, except that catalyst ligand I is used. 1 Replace with catalyst ligand I 2 The data results are shown in Table 1.

[0125] Example 3 uses catalyst ligand I 3 (R 1 =Cy,R 2 =H) to carry out ethylene oligomerization reaction

[0126] Same as Example 1, except that catalyst ligand I is used. 1 Replace with catalyst ligand I 3 The data results are shown in Table 1.

[0127] Example 4 uses catalyst ligand I 4 (R 1 =Ph,R 2 =H) to carry out ethylene oligomerization reaction

[0128] Same as Example 1, except that catalyst ligand I is used. 1 Replace with catalyst ligand I 4 The data results are shown in Table 1.

[0129] Example 5 uses catalyst ligand I 5 (R 1 =Me,R 2 =H) to carry out ethylene oligomerization reaction

[0130] Same as Example 1, except that catalyst ligand I is used. 1 Replace with catalyst ligand I 5 The data results are shown in Table 1.

[0131] Example 6 uses catalyst complex II 1 Ethylene oligomerization reaction

[0132] A 300 mL stainless steel polymerization reactor was used. The autoclave was heated to 80 °C, vacuumed and replaced with nitrogen several times, then filled with ethylene after displacement, and then reduced to the set temperature. Then methylcyclohexane was added at 40 °C, then 0.5 μmol of catalyst complex II was added 1 (R 1 = t-Bu, R 2 = H, M = Cr, Xn= Cl3), and finally 100 μmol of cocatalyst modified methylaluminoxane (MMAO) was added, the total volume of the mixed solution was 100 mL, and the molar ratio of catalyst complex and cocatalyst was 1:500. The reaction pressure was controlled at 3 MPa, and ethylene was introduced to carry out ethylene oligomerization.

[0133] After half an hour, the reaction was completed, the system was cooled to room temperature, the gaseous product was collected in a gas metering tank, the liquid product was collected in a conical flask, 1 mL of ethanol was added as a terminator to terminate the reaction. After the gaseous and liquid products were metered, gas chromatography analysis (chromatograph was Hewlett Packard 5890) was carried out. The data results are shown in Table 1.

[0134] Example 7 used catalyst complex II 2 to carry out ethylene oligomerization

[0135] The same as Example 6, except that the catalyst complex II 1 was replaced by catalyst complex II 2 . The data results are shown in Table 1.

[0136] Example 8 used catalyst ligand I 2 to carry out ethylene oligomerization

[0137] The same as Example 1, except that the modified methylaluminoxane was replaced by triethylaluminum. The data results are shown in Table 1.

[0138] Example 9 used catalyst ligand I 1 to carry out ethylene oligomerization

[0139] The same as Example 1, except that the tris(tetrahydrofuran)chromium chloride was replaced by acetylacetone chromium. The data results are shown in Table 1.

[0140] Example 10 used catalyst ligand I 1 to carry out ethylene oligomerization

[0141] The same as Example 1, except that the reaction temperature was replaced by 30 °C instead of 40 °C. The data results are shown in Table 1.

[0142] Example 11 used catalyst ligand I 1 to carry out ethylene oligomerization

[0143] The same as Example 1, except that the reaction temperature was changed from 40°C to 60°C. The data results are shown in Table 1.

[0144] Example 12 employed catalyst ligand I 1 Ethylene oligomerization reaction was carried out

[0145] The same as Example 1, except that the reaction temperature was changed from 40°C to 80°C. The data results are shown in Table 1.

[0146] Example 13 employed catalyst ligand I 1 Ethylene oligomerization reaction was carried out

[0147] The same as Example 1, except that the reaction temperature was changed from 40°C to 100°C. The data results are shown in Table 1.

[0148] Example 14 employed catalyst complex II 1 Ethylene oligomerization reaction was carried out

[0149] The same as Example 6, except that the reaction pressure was changed from 3 MPa to 5 MPa. The data results are shown in Table 1.

[0150] Comparative Example 1 employed compound bis[(S,S)-(phenyl)2PCH(Me)CH(Me)P(phenyl)2dichloro(μ-chloro)chromium] for ethylene oligomerization reaction

[0151] The method employed was described in Comparative Example 2 of CN104169003A. The data results are shown in Table 1.

[0152] Comparative Example 2 employed compound bis[(S,S)-(o-fluoro-phenyl)2PCH(Me)CH(Me)P(o-fluoro-phenyl)2dichloro(μ-chloro)chromium] for ethylene oligomerization reaction

[0153] The method employed was described in Example 4 of CN104169003A. The data results are shown in Table 1.

[0154] Comparative Example 3 employed compound bis[(S,S)-(phenyl)2PCH(Me)CH(Me)P(phenyl)2dichloro(μ-chloro)chromium] for ethylene oligomerization reaction

[0155] Complex II 1 was replaced by compound bis[(S,S)-(phenyl)2PCH(Me)CH(Me)P(phenyl)2dichloro(μ-chloro)chromium], and the other method was the same as Example 6. The data results are shown in Table 1.

[0156] Comparative Example 4 employed compound bis[(S,S)-(o-fluoro-phenyl)2PCH(Me)CH(Me)P(o-fluoro-phenyl)2dichloro(μ-chloro)chromium] for ethylene oligomerization reaction

[0157] The complex II 1 is replaced by the compound bis[(S,S)-(o-fluoro-phenyl)2PCH(Me)CH(Me)P(o-fluoro-phenyl)2]dichloro(mu-chloro)chromium, and other methods are the same as in Example 6. The data results are shown in Table 1.

[0158] Table 1

[0159]

[0160]

[0161] From the data in Table 1, it can be seen that the catalytic activity of the phenyl bridged bisphosphine type catalyst provided by the present application is more than 0.7×10 8 g·mol(Cr) -1 ·h -1 , and can be as high as 3.6×10 8 g·mol(Cr) -1 ·h -1 Under different conditions, the total selectivity of 1-hexene and 1-octene is more than 91wt%, and can be more than 95wt%. Compared with the catalyst of Comparative Example 1, the catalytic activity of the catalyst composition provided by the present application is significantly improved, especially the content of 1-hexene in C6 is greatly increased, and the by-products such as cyclic olefins and cyclization products are significantly reduced. Compared with the catalyst of Comparative Example 2, the catalytic activity of the catalyst composition provided by the present application is significantly improved. Compared with the catalyst of Comparative Example 3, the catalytic activity of the catalyst composed of the asymmetric bisphosphine ligand provided by the present application is significantly improved, especially the content of 1-hexene in C6 is greatly increased, and the production of by-products such as cyclic olefins and cyclization products is reduced. Compared with the catalyst of Comparative Example 4, the catalytic activity of the catalyst composition provided by the present application is significantly improved by about 4 times, which shows that the catalyst described in the present application has better performance. The change of the structure of the catalyst ligand affects the coordination ability and electronic effect of the ligand, and thus has a very obvious effect on the catalytic performance.

[0162] The catalyst composition in the present application can effectively catalyze the trimerization and tetramerization reactions of ethylene, and has the advantages of rapid initiation, stable operation, good repeatability, strong practicability and wide industrialization prospect.

[0163] It should be noted that the above-mentioned examples illustrate rather than limit the application, which is defined by the scope of the claims. The application has been described in terms of specific embodiments thereof which are intended to be illustrative only and not restrictive. Numerous modifications of the application can be devised without departing from the spirit and scope of the application. While the present application has been described with reference to the specific methods, materials and examples described herein, the application is not to be limited to the particulars disclosed. It is recognized that variations in the methods and in the materials, among others, can be employed and the desired results would be attained.

Claims

1. A fluorine-containing ligand having a structure represented by formula (I), ###0001### (I) wherein R1 represents a hydrogen atom or a substituent; and R2 represents a hydrogen atom or a substituent. （I） In formula (I), R 1 and R 2 are the same or different, each independently selected from the group consisting of hydrogen, a substituted or unsubstituted C1-C6alkyl group, a substituted or unsubstituted C3-C10cycloalkyl group, a substituted or unsubstituted C6-C20aryl group, and R 1 and R 2 are not simultaneously hydrogen; R1-R 18 each independently is selected from the group consisting of hydrogen, a substituted or unsubstituted C1-C10alkyl group, and a substituted or unsubstituted C1-C10alkoxy group; The substituent is selected from a cyano group, a C1-C10 alkyl group or a C1-C10 alkoxy group.

2. The fluoro-based ligand according to claim 1, wherein The C1-C10 alkyl group in the substituent is selected from a methyl group, an ethyl group, a n-propyl group, an iso-propyl group, a n-butyl group, a t-butyl group, an iso-butyl group, a n-pentyl group, an iso-pentyl group, a n-hexyl group and a n-heptyl group; and the C1-C10 alkoxy group is selected from a methoxy group, an ethoxy group, a n-propoxy group, an iso-propoxy group, a n-butoxy group, a t-butoxy group, an iso-butoxy group, a n-pentoxy group, an iso-pentoxy group, a n-hexyloxy group and a n-heptyloxy group.

3. Fluorine-containing ligand according to claim 1 or 2, characterized in that R1-R 18 each independently is selected from the group consisting of hydrogen, methyl, ethyl, n-propyl, i-propyl, n-butyl, t-butyl, i-butyl, n-pentyl, i-pentyl, n-hexyl, n-heptyl, methoxy, ethoxy, n-propoxy, i-propoxy, n-butoxy, t-butoxy, i-butoxy, n-pentoxy, i-pentoxy, n-hexoxy, and n-heptoxy.

4. The fluoro-based ligand according to claim 1 or 2, characterized in that, R 1 and R 2 are identical or different, each independently selected from the group consisting of hydrogen, methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl, t-butyl, cyclopropyl, cyclopentyl, cyclohexyl and phenyl with or without substituents.

5. A fluorine-containing metal complex having a structure represented by formula (II), ###0002### (II) wherein n represents 1, 2 or 3. The transition metal is selected from chromium, molybdenum, iron, titanium, zirconium and nickel; In formula (II), R 3 and R 4 are the same or different, each independently selected from the group consisting of hydrogen, a substituted or unsubstituted C1-C6 alkyl group, a substituted or unsubstituted C3-C10 cycloalkyl group, and a substituted or unsubstituted C6-C20 aryl group; R 19 -R 36 are each independently selected from the group consisting of hydrogen, a substituted or unsubstituted C1-C10 alkyl group, and a substituted or unsubstituted C1-C10 alkoxy group; M is selected from a transition metal element; X is selected from a halogen; n represents the number of satisfying the valence state of M; and the substituents are selected from the group consisting of a cyano group, a C1-C10 alkyl group, and a C1-C10 alkoxy group.

6. Metal complex according to claim 5, characterized in that, and / or the halogen is selected from fluorine, chlorine, bromine and iodine; 7. The metal complex of claim 5, wherein and / or the C1-C10 alkyl group in the substituent is selected from a methyl group, an ethyl group, a n-propyl group, an iso-propyl group, a n-butyl group, a t-butyl group, an iso-butyl group, a n-pentyl group, an iso-pentyl group, a n-hexyl group and a n-heptyl group; and the C1-C10 alkoxy group is selected from a methoxy group, an ethoxy group, a n-propoxy group, an iso-propoxy group, a n-butoxy group, a t-butoxy group, an iso-butoxy group, a n-pentoxy group, an iso-pentoxy group, a n-hexyloxy group and a n-heptyloxy group.

10. An ethylene oligomerization catalyst composition comprising a fluorine-containing ligand, a transition metal compound and an aluminum-containing compound; the fluorine-containing ligand having a structure represented by formula (I), ###0003### (I) wherein R1 represents a hydrogen atom or a substituent; and R2 represents a hydrogen atom or a substituent. The substituent is selected from a cyano group, a C1-C10 alkyl group or a C1-C10 alkoxy group.

8. Metal complex according to any one of claims 5 to 7, characterized in that R 19 -R 36 each independently is selected from the group consisting of hydrogen, methyl, ethyl, n-propyl, i-propyl, n-butyl, t-butyl, i-butyl, n-pentyl, i-pentyl, n-hexyl, n-heptyl, methoxy, ethoxy, n-propoxy, i-propoxy, n-butoxy, t-butoxy, i-butoxy, n-pentoxy, i-pentoxy, n-hexoxy, and n-heptoxy.

9. Metal complex according to any one of claims 5 to 7, characterized in that R 3 and R 4 are identical or different, each independently selected from the group consisting of hydrogen, methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl, t-butyl, cyclopropyl, cyclopentyl, cyclohexyl and phenyl with or without substituents. The C1-C10 alkyl group in the substituent is selected from a methyl group, an ethyl group, a n-propyl group, an iso-propyl group, a n-butyl group, a t-butyl group, an iso-butyl group, a n-pentyl group, an iso-pentyl group, a n-hexyl group and a n-heptyl group; and the C1-C10 alkoxy group is selected from a methoxy group, an ethoxy group, a n-propoxy group, an iso-propoxy group, a n-butoxy group, a t-butoxy group, an iso-butoxy group, a n-pentoxy group, an iso-pentoxy group, a n-hexyloxy group and a n-heptyloxy group. （I） In formula (I), R 1 and R 2 are the same or different, each independently selected from the group consisting of hydrogen, a substituted or unsubstituted C1-C6alkyl group, a substituted or unsubstituted C3-C10cycloalkyl group, a substituted or unsubstituted C6-C20aryl group; R1-R 18 each independently is selected from the group consisting of hydrogen, a substituted or unsubstituted C1-C10alkyl group, and a substituted or unsubstituted C1-C10alkoxy group; The transition metal compound is selected from one or more of a chromium compound, a molybdenum compound, an iron compound, a titanium compound, a zirconium compound and a nickel compound; 11. The catalyst composition of claim 10, wherein, and / or the molar ratio of the catalyst ligand, the transition metal compound and the aluminum-containing compound is 1 : (0.1-10) : (1-1000); 12. The catalyst composition of claim 11, wherein, R1-R 18 each independently is selected from the group consisting of hydrogen, methyl, ethyl, n-propyl, i-propyl, n-butyl, t-butyl, i-butyl, n-pentyl, i-pentyl, n-hexyl, n-heptyl, methoxy, ethoxy, n-propoxy, i-propoxy, n-butoxy, t-butoxy, i-butoxy, n-pentoxy, i-pentoxy, n-hexoxy, and n-heptoxy.

13. The catalyst composition of claim 11, wherein, R 1 and R 2 are identical or different, each independently selected from the group consisting of hydrogen, methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl, t-butyl, cyclopropyl, cyclopentyl, cyclohexyl and phenyl with or without substituents.

14. The catalyst composition of any of claims 11-13, wherein, and / or the aluminum-containing compound is selected from an organoaluminum compound. The transition metal compound is selected from one or more of acetylacetone chromium, chromium isooctanoate, tris(tetrahydrofuran)trichlorochromium and bis(tetrahydrofuran)dichlorochromium. The molar ratio of the catalyst ligand, the transition metal compound and the aluminum-containing compound is 1 : (0.25-2) : (10-700).

15. The catalyst composition of any of claims 11-13, wherein, The molar ratio of the catalyst ligand, the transition metal compound and the aluminum-containing compound is 1 : (0.5-2) : (100-500).

16. The catalyst composition of any one of claims 11-13, wherein, The aluminum-containing compound is selected from one or more of an alkylaluminum compound, an alkoxyaluminum compound and a chloroalkylaluminum compound.

17. The catalyst composition of any of claims 11-13, wherein, The aluminum-containing compound is selected from one or more of methylaluminoxane, trimethylaluminum, triethylaluminum, triisobutylaluminum, tri-n-hexylaluminum, tri-n-octylaluminum, diethylaluminum chloride, ethylaluminum dichloride, ethylaluminoxane and modified methylaluminoxane.

18. The catalyst composition of any of claims 11-13, wherein, ​ 19. The catalyst composition of any of claims 11-13, wherein, ​ 20. An ethylene oligomerization catalyst composition comprising the metal complex of any one of claims 5-9 and an aluminum-containing compound.

21. The catalyst composition of claim 20, wherein, The molar ratio of the metal complex to the aluminum-containing compound is 1: (1-1000); and / or the aluminum-containing compound is selected from the group consisting of organoaluminum compounds.

22. The catalyst composition of claim 20, wherein, The molar ratio of the metal complex to the aluminum-containing compound is 1: (10-700).

23. The catalyst composition of claim 20, wherein, The molar ratio of the metal complex to the aluminum-containing compound is 1: (100-500).

24. The catalyst composition of any one of claims 20-23, wherein, The aluminum-containing compound is selected from one or more of the group consisting of alkylaluminum compounds, alkoxyaluminum compounds, and chlorinated alkylaluminum compounds.

25. The catalyst composition of any one of claims 20-23, wherein, The aluminum-containing compound is selected from one or more of the group consisting of methylaluminoxane, trimethylaluminum, triethylaluminum, triisobutylaluminum, tri-n-hexylaluminum, tri-n-octylaluminum, diethylaluminum chloride, ethylaluminum dichloride, ethylaluminoxane, and modified methylaluminoxane.

26. An ethylene oligomerization method comprising performing an ethylene oligomerization reaction in an organic solvent in the presence of the catalyst composition according to any one of claims 10-25.

27. The method of claim 26, wherein, The ethylene oligomerization reaction is an ethylene trimerization and tetramerization reaction.

28. The method of claim 26 or 27, wherein, The organic solvent is an aliphatic hydrocarbon compound and / or an aromatic hydrocarbon compound; and / or the reaction temperature of the reaction is 0-200°C; and / or the pressure of the reaction is 0.1-20 MPa; and / or the concentration of the catalyst composition, calculated on the basis of the volume of the organic solvent, is 1-20 pmol / L of transition metal.

29. The method of claim 28, wherein, The aliphatic hydrocarbon compound is at least one of a straight-chain alkane, a branched-chain alkane, and a cycloalkane.

30. The method of claim 28, wherein, The aliphatic hydrocarbon compound is at least one of pentane, heptane, hexane, cyclohexane, and methylcyclohexane; and / or the aromatic hydrocarbon compound is at least one of benzene, toluene, xylene, monochlorobenzene, dichlorobenzene, trichlorobenzene, and monochlorotoluene.

31. The method of claim 28, wherein, The reaction temperature of the reaction is 0-100°C.

32. The method of claim 28, wherein, The reaction temperature of the reaction is 30-90°C.

33. The method of claim 28, wherein, The pressure of the reaction is 0.5-5 MPa.

34. The method of claim 28, wherein, The pressure of the reaction is 2.0-5.0 MPa.

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