Chromium catalyst precursor, ethylene oligomerization catalyst comprising the same, and method for producing ethylene oligomer

Abstract

The present invention relates to a chromium catalyst precursor, an ethylene oligomerization catalyst comprising the same, and a method for preparing an ethylene oligomer using the same, and more particularly, to a chromium catalyst precursor which can oligomerize ethylene with high activity and high selectivity even without using methylaluminoxane (MAO) or modified methylaluminoxane (MMAO), an oligomerization catalyst comprising the same, and a method for preparing an ethylene oligomer using the same.

Description

Technical Field

[0001] This invention relates to a chromium catalyst precursor, an ethylene oligomerization catalyst containing the chromium catalyst precursor, and a method for preparing ethylene oligomers using the ethylene oligomerization catalyst. More specifically, it relates to a chromium catalyst precursor that can oligomerize ethylene with high activity and high selectivity even without the use of methylaluminoxane (MAO) or modified methylaluminoxane (MMAO), an oligomerization catalyst containing the chromium catalyst precursor, and a method for preparing ethylene oligomers using the oligomerization catalyst. Background Technology

[0002] Ethylene oligomers, specifically 1-hexene and 1-octene, are monomers or comonomers used to prepare linear low-density polyethylene and are important commercial raw materials widely used in polymerization processes. They are obtained by purifying the products formed from the oligomerization reaction of ethylene.

[0003] However, existing ethylene oligomerization processes are inefficient, often resulting in the formation of large amounts of butene, higher oligomers, and polyethylene along with 1-hexene and 1-octene. These existing ethylene oligomerization techniques typically form various α-olefins based on Schulze-Flory or Poisson product distributions, thus resulting in relatively low levels of 1-hexene and 1-octene in the products.

[0004] In recent years, research has been conducted on the selective trimerization of ethylene to produce 1-hexene or the selective tetramerization to produce 1-octene through transition metal catalysis. Most known transition metal catalysts are chromium-based catalysts.

[0005] As a representative example of selective oligomerization of ethylene, a method for selectively forming 1-octene and 1-hexene using a catalyst system consisting of a trivalent chromium compound (CrCl3 or Cr(acac)3), (i-PrN(PPh2)2) as a bisphosphine ligand, and methylaluminoxane (MAO) is reported (US Patent 7511183B2).

[0006] However, the catalyst system suffers from several drawbacks: high catalytic activity can only be achieved by using an excessive amount of high-valence methylaluminoxane (MAO), and significant amounts of polyethylene (PE) are formed. Furthermore, catalytic activity decreases at high temperatures, leading to reduced production and selectivity of olefins, particularly 1-octene, and increased formation of the byproduct PE. This results in pipe blockage and scaling, inevitably causing process interruptions and thus posing serious problems in olefin polymerization processes.

[0007] Therefore, much effort has been made to develop catalyst systems that do not use the expensive methylaluminoxane (MAO) by replacing MAO with noncoordinate anions. However, compared with most catalyst systems using MAO, these systems often exhibit lower activity or require separate separation and purification processes, making them unsuitable for commercial applications.

[0008] As an example of using a catalyst system without MAO, a literature report describes the further reaction of sterically hindered aluminum anions (soft aluminum anion) after the preparation and separation of chromium-phosphine complexes to achieve oligomerization activity (Organometallics 2007, 26, 2782-2787). However, compared with MAO co-catalyst systems with the same ligands, the activity is as low as 50%, and it uses expensive aluminum anion raw materials, so it may not be suitable for practical commercial applications.

[0009] As another example of using borate cocatalysts to replace MAO, a paper (WO2010 / 092554A1) reported the use of a mixture of chromium(III) precursors with triethylaluminum (TEAL), PNP ligands, and borate cocatalysts as a catalyst to achieve oligomerization activity without a separation process. However, the preparation and use of the catalyst solution may be limited due to the use of high-valence chromium precursors such as chromium(III) 2-ethylhexanoate (Cr(2-ethylhexanoate)3) and borate cocatalysts with very low solubility such as aniline borate.

[0010] In addition, a literature report describes a catalyst preparation that achieves oligomerization activity by reacting triethylaluminum (TEAL), boron co-catalyst, and chromium (III) precursor sequentially to synthesize a catalyst precursor, followed by reaction of PNP ligands. However, due to the complexity of the process, a separation process is required after catalyst synthesis, and the available PNP ligand structures are limited, thus the preparation and use of the catalyst may be restricted.

[0011] Therefore, there is a need to develop a catalyst, catalyst system, or oligomerization method that can use inexpensive raw materials and apply a variety of ligands to produce 1-hexene and 1-octene with high activity and selectivity, even without the use of MAO, and can reduce the generation of undesirable polyethylene byproducts. Summary of the Invention Technical problems to be solved

[0012] The purpose of this invention is to provide a chromium catalyst precursor that enables ethylene to oligomerize with high activity and high selectivity even without the use of methylaluminoxane (MAO) or modified methylaluminoxane (MMAO), and an oligomerization catalyst containing the chromium catalyst precursor.

[0013] The purpose of this invention is to provide a chromium catalyst precursor that exhibits excellent stability and can achieve high-activity and high-selectivity oligomerization of ethylene without long-term degradation of activity, as well as an oligomerization catalyst containing the chromium catalyst precursor.

[0014] Another object of the present invention is to provide an oligomerization method for ethylene, in which ethylene can be oligomerized with high activity and high selectivity even without the use of methylaluminoxane (MAO) or modified methylaluminoxane (MMAO), thereby preparing 1-hexene and 1-octene in high yield. Technical solution

[0015] This invention provides a precursor for an ethylene oligomerization catalyst that enables ethylene to oligomerize with high activity and selectivity even without the use of methylaluminoxane (MAO) or modified methylaluminoxane (MMAO). The catalyst precursor of this invention can be a chromium catalyst precursor represented by the following chemical formula 1:

[0016] [Chemical Formula 1] [crM 1 (L) x (R) 6-x ] n (w) m

[0017] In the chemical formula 1,

[0018] M 1 It is a Group 13 element;

[0019] L is a ligand in the form of a β-ketoenol salt;

[0020] R is a halogen, C1-C 10 Alkoxy or C6-C 20 aryloxy;

[0021] W is a neutral coordinating ligand;

[0022] n is an integer of 1 or 2;

[0023] x is an integer from 1 to 6;

[0024] m is an integer from 0 to 4.

[0025] In a chromium catalyst precursor according to one embodiment, the M 1 It can be boron (B) or aluminum (Al).

[0026] In a chromium catalyst precursor according to one embodiment, L can be an enol ligand represented by the following chemical formula A.

[0027] [Chemical Formula A]

[0028] In the chemical formula A,

[0029] R 1 and R 3 Each can be independently a halogen, a hydrocarbon group, a substituted hydrocarbon group, a heterohydrocarbon group, or a substituted heterohydrocarbon group;

[0030] R 2 It can be hydrogen, halogen, hydrocarbon group, substituted hydrocarbon group, heterohydrocarbon group or substituted heterohydrocarbon group;

[0031] The R 1 and R 2 , or R 3 and R 2 A ring can be formed by linking alkylene groups, substituted alkylene groups, heteroalkylene groups, or substituted heteroalkylene groups.

[0032] In a chromium catalyst precursor according to one embodiment, W can be a nitrile having 2 to 30 carbon atoms, a cyclic or acyclic ether having 2 to 30 carbon atoms, or water (H2O), preferably acetonitrile (ACN), tetrahydrofuran (THF), diethyl ether, or water (H2O).

[0033] In a chromium catalyst precursor according to one embodiment, the M 1 It can be boron (B) or aluminum (Al); R can be halogen or C1-C. 10 Alkyl group; W can be acetonitrile (ACN), tetrahydrofuran (THF), diethyl ether or water (H2O); m can be an integer from 2 to 4; x can be an integer from 1 to 6; L can be an acetylacetone ligand with the following structure.

[0034] (R 1 and R 3 Each independently is C1-C 10 Alkyl or C6-C 20 Aryl, the R 1 and R 3 The alkyl and aryl groups can be further selected from halogens, C1-C... 10 Alkyl, C6-C 20 Aryl, halogenated C1-C 10 Alkyl and halogenated C6-C 20 One or more substituents in the aryl group are substituted;

[0035] R2 Hydrogen, halogen, C1-C 10 Alkyl or C6-C 20 Aryl, the R 2 The alkyl and aryl groups can be further selected from halogens, C1-C... 10 Alkyl, C6-C 20 Aryl, halogenated C1-C 10 Alkyl and halogenated C6-C 20 One or more of the aryl groups are substituted;

[0036] The R 1 and R 2 , or R 3 and R 2 Through C3-C 10 Alkylene, C3-C 10 alkenyl, C6-C 20 Aromatic, C3-C 10 Heteroalkylene, C3-C 10 Heteroene or C6-C 20 (The heteroarylene groups connect to form a ring.)

[0037] In a chromium catalyst precursor according to one embodiment, the M 1 It can be boron (B); L can be acetylacetonate; R can be C1-C 10 Alkoxy group; W can be acetonitrile (ACN), tetrahydrofuran (THF), diethyl ether, or water (H2O); m can be an integer from 2 to 4; x can be an integer from 1 to 6.

[0038] In a chromium catalyst precursor according to one embodiment, the M 1 It can be aluminum (Al); L can be acetylacetonate; R can be halogen; W can be acetonitrile (ACN), tetrahydrofuran (THF), diethyl ether or water (H2O); m can be an integer from 2 to 4; x can be an integer from 1 to 6.

[0039] Furthermore, the present invention provides an ethylene oligomerization catalyst that enables ethylene to oligomerize with high activity and high selectivity even without the use of methylaluminoxane (MAO) or modified methylaluminoxane (MMAO). The ethylene oligomerization catalyst of the present invention comprises a chromium catalyst precursor represented by the aforementioned chemical formula 1 and a heteroatom ligand.

[0040] In one embodiment of the ethylene oligomerization catalyst, the heteroatom ligand may be a phosphine ligand and may be represented by the following chemical formula 3:

[0041] [Chemical Formula 3] (R 12 (R) 11PYZ

[0042] In the chemical formula 3

[0043] R 11 and R 12 Each can be independently a hydrocarbon group, a heterohydrocarbon group, a substituted hydrocarbon group, or a substituted heterohydrocarbon group;

[0044] Y is the linking group between P and Z;

[0045] Z is *-P(R) 13 (R) 14 )or

[0046] Ring A and ring B are each an aromatic ring independently;

[0047] L 1 and L 2 Each can be independently a single bond, a heteroatom, a substituted heteroatom, -C(=O)- or -CR'R”-;

[0048] R' and R” can each be hydrogen, hydrocarbon group, substituted hydrocarbon group, heterohydrocarbon group or substituted heterohydrocarbon group independently;

[0049] R 13 To R 16 Each can be independently a hydrocarbon group, a heterohydrocarbon group, a substituted hydrocarbon group, or a substituted heterohydrocarbon group;

[0050] c and d are each independent integers from 0 to 4.

[0051] In one embodiment of the ethylene oligomerization catalyst, in the heteroatom ligand of formula 3, Y can be an alkylene group, -N(R) group, or a hydrocarbon group. 21 )-、-N(R 21 )-N(R 22 )-、=C(R 23 )-N(R 21 )-、-N(R 21 )-C(R 23 (R) 24 - or -N(R) 21 )-L 3 -N(R 22 )-;R 21 To R 24 It can be independently hydrogen, a hydrocarbon group, a substituted hydrocarbon group, a heterohydrocarbon group, a substituted heterohydrocarbon group, or a substituted heteroatom; L 3 It can be a hydrocarbon group.

[0052] In one embodiment of the ethylene oligomerization catalyst, the heteroatom ligand of Formula 3 may be a heteroatom ligand with a PNP framework structure represented by Formula 4 or Formula 5.

[0053] [Chemical Formula 4]

[0054] [Chemical Formula 5]

[0055] In chemical formulas 4 and 5,

[0056] Rings A and B are each independently C6-C 20 Aromatic rings;

[0057] R 11 To R 14 R 15 and R 16 Each independently is C6-C 20 Aryl, C6-C 20 Aryl C1-C 10 Alkyl, C6-C 20 Aryl C2-C 10 alkenyl, C6-C 20 Aryl C2-C 10 alkynyl group, C1-C 10 Alkyl, C2-C 10 alkenyl, C2-C 10 alkynyl group, C1-C 10 Alkoxy, C6-C 20 aryloxy group, C1-C 10 alkoxycarbonyl, C1-C 10 Alkyl carbonyl group, C2-C 10 alkenyl carbonyl group, C2-C 10 alkynyl carbonyl group, amino carbonyl group, C1-C 10 Alkyl carbonyl amino, C2-C 10 alkenyl carbonyl amino, C2-C 10 alkynyl carbonyl amino, C3-C 10 Cycloalkyl, mercapto C1-C 10 Alkyl, mercapto C2-C 10 alkenyl, mercapto C2-C 10 alkynyl group, C3-C 20 Heteroaryl, 5- to 7-membered heterocyclic alkyl, -NR a1 R b1 or -SiR c1 R d1 R e1 ;

[0058] R a1 and R b1 Each independently is hydrogen, C1-C 10 Alkyl, C2-C10 alkenyl, C2-C 10 alkynyl group, C6-C 20 Aryl, C1-C 10 Alkylamino, C2-C 10 alkenyl amino or C2-C 10 alkynylamino;

[0059] R c1 For C1-C 10 Alkyl, C2-C 10 alkenyl, C2-C 10 alkynyl or C6-C 20 Aryl;

[0060] R d1 and R e1 Each independently is hydrogen, C1-C 10 Alkyl, C2-C 10 alkenyl, C2-C 10 alkynyl or C6-C 20 Aryl;

[0061] R 21 For C1-C 10 Alkyl, C2-C 10 alkenyl, C2-C 10 alkynyl group, C6-C 20 Aryl, C6-C 20 Aryl C1-C 10 Alkyl, C6-C 20 Aryl C2-C 10 alkenyl, C6-C 20 Aryl C2-C 10 alkynyl group, C3-C 10 cycloalkyl, C3-C 20 Heteroaryl, 5- to 7-membered heterocyclic alkyl, C1-C 10 Alkoxy, C6-C 20 aryloxy group, C1-C 10 alkoxycarbonyl, C1-C 10 Alkyl carbonyl group, C2-C 10 alkenyl carbonyl group, C2-C 10 alkynyl carbonyl group, amino carbonyl group, C1-C 10 Alkyl carbonyl amino, C2-C 10 alkenyl carbonyl amino, C2-C 10 alkynyl carbonyl amino, -NR a2 R b2 or -SiR c2 R d2 R e2 ;

[0062] L 1and L 2 Each can be independently a single bond, -O-, -S-, -NR'-, -P(=O)R'-, -P(=Se)R'-, -P(=S)R'-, -SiR'R”-, -CR'R”-, or -C(=O)-;

[0063] R' and R” are each independently hydrogen, C1-C 10 Alkyl, C2-C 10 alkenyl, C2-C 10 alkynyl group, C6-C 20 Aryl, C6-C 20 Aryl C1-C 10 Alkyl, C6-C 20 Aryl C2-C 10 alkenyl, C6-C 20 Aryl C2-C 10 alkynyl group, C3-C 10 cycloalkyl, C3-C 20 Heteroaryl, 5- to 7-membered heterocyclic alkyl, C1-C 10 Alkoxy, C6-C 20 aryloxy group, C1-C 10 alkoxycarbonyl, C1-C 10 Alkyl carbonyl group, C2-C 10 alkenyl carbonyl group, C2-C 10 alkynyl carbonyl group, amino carbonyl group, C1-C 10 Alkyl carbonyl amino, C2-C 10 alkenyl carbonyl amino, C2-C 10 alkynyl carbonyl amino, -NR a3 R b3 or -SiR c3 R d3 R e3 ;

[0064] R a2 R b2 R a3 and R b3 Each independently is hydrogen, C1-C 10 Alkyl, C2-C 10 alkenyl, C2-C 10 alkynyl or C6-C 20 Aryl;

[0065] R c2 and R c3 Each independently is C1-C 10 Alkyl, C2-C 10 alkenyl, C2-C 10 alkynyl or C6-C 20 Aryl;

[0066] R d2 R e2 R d3 and R e3 Each independently is hydrogen, C1-C 10 Alkyl, C2-C 10 alkenyl, C2-C 10 alkynyl or C6-C 20 Aryl;

[0067] c and d are each independent integers from 0 to 4;

[0068] The R 11 To R 14 R 15 and R 16 aryl, arylalkyl, alkyl, arylalenyl, alkenyl, arylynyl, alkoxy, aryloxy, cycloalkyl, heteroaryl or heterocycloalkyl and R 21 The alkyl, alkenyl, aryl, arylalkyl, arylalkenyl, arylynyl, cycloalkyl, heteroaryl, heterocycloalkyl, alkoxy, aryloxy, alkoxycarbonyl, alkylcarbonyloxy, alkenylcarbonyloxy, alkynylcarbonyloxy, aminocarbonyl, alkylcarbonylamino, alkenylcarbonylamino, or alkynylcarbonylamino groups of R' and R" may be further selected from halogens, C1-C 10 Alkyl, halogenated C1-C 10 Alkyl, C2-C 10 alkenyl, C2-C 10 alkynyl group, C1-C 10 Alkoxy, halogenated C1-C 10 Alkoxy, C6-C 20 Aryl, C6-C 20 Aryloxy, 5- to 7-membered heterocyclic alkyl, -NR a4 R b4 and -SiR c4 R d4 R e4 One or more substitutions in; R a4 and R b4 Each independently is hydrogen, C1-C 10 Alkyl, C2-C 10 alkenyl, C2-C 10 alkynyl or C6-C 20 Aryl, R c4 To R e4 Each independently is C1-C 10 Alkyl or C1-C 10 Alkyl group.

[0069] In an ethylene oligomerization catalyst according to one embodiment, in the heteroatom ligands of formulas 3 and 5, L 1 and L2 Each can be a single bond or -O- independently.

[0070] In one embodiment of the ethylene oligomerization catalyst, the heteroatom ligand of chemical formula 3 may be a heteroatom ligand represented by chemical formula 6.

[0071] [Chemical Formula 6]

[0072] In the chemical formula 6,

[0073] R 11 and R 12 Each independently is C6-C 20 Aryl, C6-C 20 Aryl C1-C 10 Alkyl, C6-C 20 Aryl C2-C 10 alkenyl, C6-C 20 Aryl C2-C 10 alkynyl group, C1-C 10 Alkyl, C2-C 10 alkenyl, C2-C 10 alkynyl group, C1-C 10 Alkoxy, C6-C 20 aryloxy group, C1-C 10 alkoxycarbonyl, C1-C 10 Alkyl carbonyl group, C2-C 10 alkenyl carbonyl group, C2-C 10 alkynyl carbonyl group, amino carbonyl group, C1-C 10 Alkyl carbonyl amino, C2-C 10 alkenyl carbonyl amino, C2-C 10 alkynyl carbonyl amino, C3-C 10 Cycloalkyl, mercapto C1-C 10 Alkyl, mercapto C2-C 10 alkenyl, mercapto C2-C 10 alkynyl group, C3-C 20 Heteroaryl, 5- to 7-membered heterocyclic alkyl, -NR a1 R b1 or -SiR c1 R d1 R e1 ;

[0074] R a1 and R b1 Each independently is hydrogen, C1-C 10 Alkyl, C2-C 10 alkenyl, C2-C 10 alkynyl group, C6-C 20Aryl, C1-C 10 Alkylamino, C2-C 10 alkenyl amino or C2-C 10 alkynylamino;

[0075] R c1 For C1-C 10 Alkyl, C2-C 10 alkenyl, C2-C 10 alkynyl or C6-C 20 Aryl;

[0076] R d1 and R e1 Each independently is hydrogen, C1-C 10 Alkyl, C2-C 10 alkenyl, C2-C 10 alkynyl or C6-C 20 Aryl;

[0077] R 21 For C1-C 10 Alkyl, C2-C 10 alkenyl, C2-C 10 alkynyl group, C6-C 20 Aryl, C6-C 20 Aryl C1-C 10 Alkyl, C6-C 20 Aryl C2-C 10 alkenyl, C6-C 20 Aryl C2-C 10 alkynyl group, C3-C 10 cycloalkyl, C3-C 20 Heteroaryl, 5- to 7-membered heterocyclic alkyl, C1-C 10 Alkoxy, C6-C 20 aryloxy group, C1-C 10 alkoxycarbonyl, C1-C 10 Alkyl carbonyl group, C2-C 10 alkenyl carbonyl group, C2-C 10 alkynyl carbonyl group, amino carbonyl group, C1-C 10 Alkyl carbonyl amino, C2-C 10 alkenyl carbonyl amino, C2-C 10 alkynyl carbonyl amino, -NR a2 R b2 or -SiR c2 R d2 R e2 ;

[0078] R a2 and R b2 Each independently is hydrogen, C1-C 10 Alkyl, C2-C10 alkenyl, C2-C 10 alkynyl or C6-C 20 Aryl;

[0079] R c2 For C1-C 10 Alkyl, C2-C 10 alkenyl, C2-C 10 alkynyl or C6-C 20 Aryl;

[0080] R d2 and R e2 Each independently is hydrogen, C1-C 10 Alkyl, C2-C 10 alkenyl, C2-C 10 alkynyl or C6-C 20 Aryl;

[0081] The C ring and D ring are each independently benzene or naphthalene;

[0082] R 22 and R 23 Hydrogen, C1-C 10 Alkyl, C6-C 20 Aryl, C3-C 10 cycloalkyl, C6-C 20 Aryl C1-C 10 Alkyl or C1-C 10 Alkyl C6-C 20 Aryl;

[0083] The R 11 and R 12 aryl, arylalkyl, alkyl, arylalenyl, alkenyl, arylynyl, alkoxy, aryloxy, cycloalkyl, heteroaryl, heterocycloalkyl and R 21 The alkyl, alkenyl, aryl, arylalkyl, arylalkenyl, arylynyl, cycloalkyl, heteroaryl, heterocycloalkyl, alkoxy, aryloxy, alkoxycarbonyl, alkylcarbonyloxy, alkenylcarbonyloxy, alkynylcarbonyloxy, aminocarbonyl, alkylcarbonylamino, alkenylcarbonylamino, or alkynylcarbonylamino can be further selected from halogens, C1-C 10 Alkyl, halogenated C1-C 10 Alkyl, C2-C 10 alkenyl, C2-C 10 alkynyl group, C1-C 10 Alkoxy, halogenated C1-C 10 Alkoxy, C6-C 20 Aryl, C6-C 20 Aryloxy, 5- to 7-membered heterocyclic alkyl, -NR a4 R b4 and -SiRc4 R d4 R e4 One or more substitutions in; R a4 and R b4 Each independently is hydrogen, C1-C 10 Alkyl, C2-C 10 alkenyl, C2-C 10 alkynyl or C6-C 20 Aryl, R c4 To R e4 Each independently is C1-C 10 Alkyl or C1-C 10 Alkyl group.

[0084] In an ethylene oligomerization catalyst according to one embodiment, the chromium catalyst precursor of chemical formula 1 contains M 1 It can be boron (B) or aluminum (Al); R can be halogen or C1-C. 10 Alkoxy; W can be acetonitrile (ACN), tetrahydrofuran (THF), diethyl ether or water (H2O); m can be an integer from 2 to 4; x can be an integer from 1 to 6; L can be an acetylacetone ligand with the following structure.

[0085] (R 1 and R 3 Each independently is C1-C 10 Alkyl or C6-C 20 Aryl, the R 1 and R 3 The alkyl and aryl groups can be further selected from halogens, C1-C... 10 Alkyl, C6-C 20 Aryl, halogenated C1-C 10 Alkyl and halogenated C6-C 20 One or more substituents are substituted in the aryl group;

[0086] R 2 Hydrogen, halogen, C1-C 10 Alkyl or C6-C 20 Aryl, the R 2 The alkyl and aryl groups can be further selected from halogens, C1-C... 10 Alkyl, C6-C 20 Aryl, halogenated C1-C 10 Alkyl and halogenated C6-C 20 One or more of the aryl groups are substituted;

[0087] The R 1 and R 2 , or R 3 and R 2Through C3-C 10 Alkylene, C3-C 10 alkenyl, C6-C 20 aryl, C3-C 10 Heteroalkylene, C3-C 10 Heteroene or C6-C 20 (The heteroarylene groups connect to form a ring.)

[0088] Furthermore, the present invention provides a method for preparing ethylene oligomers, comprising the step of contacting a catalyst system with ethylene monomers to prepare ethylene oligomers, wherein the catalyst system comprises the ethylene oligomerization catalyst and an organoboron compound-based cocatalyst.

[0089] In one embodiment of the method for preparing ethylene oligomers, the organoboron compound-based cocatalyst may be an organoboron compound represented by the following chemical formula 9.

[0090] [Chemical Formula 9]

[0091] [R 31 R 32 R 33 Y] + [B(C6R 34 p H 5-p )4] -

[0092] In the chemical formula 9,

[0093] Y is either C or NH;

[0094] R 31 To R 33 Each independently is hydrogen, C1-C 20 Alkyl or C6-C 20 Aryl, the R 31 The alkyl or aryl groups can be further selected from C1-C1. 20 Alkyl and C6-C 20 One or more of the aryl groups are substituted;

[0095] R 34 It is fluorine, C1-C 20 Alkyl or C1-C 20 alkoxy, the R 34 The alkyl or alkoxy group can be further substituted with more than one fluorine molecule;

[0096] p is an integer from 3 to 5.

[0097] In one embodiment of the method for preparing ethylene oligomers, the catalyst system may further comprise an alkylaluminum compound represented by the following chemical formula 10.

[0098] [Chemical Formula 10]

[0099] AlR 41 R 42 R 43

[0100] In the chemical formula 10,

[0101] R 41 For C1-C 20 alkyl;

[0102] R 42 and R 43 Each independently is C1-C 20 Alkyl or halogen.

[0103] In one embodiment of the method for preparing ethylene oligomers, the ethylene oligomers may be 1-hexene, 1-octene, or mixtures thereof.

[0104] In one embodiment of the method for preparing ethylene oligomers, a hydrocarbon-based solvent can be used as the reaction solvent during the oligomerization of ethylene. Beneficial effects

[0105] The chromium catalyst precursor according to the present invention is a readily available low-cost raw material, chromium acetylacetone (III), and a reaction product of a Lewis acid containing a Group 13 element. The chromium catalyst precursor can exist in a homogeneous solution phase, thus exhibiting excellent long-term storage stability. It can then be used as an ethylene oligomerization catalyst together with heteroatom ligands and activated by an organoboron-based co-catalyst, thereby maintaining stable catalytic activity during oligomerization. It also has the advantage of being easy to apply in continuous processes.

[0106] Furthermore, the ethylene oligomerization catalyst according to the present invention comprises the chromium catalyst precursor and heteroatom ligands of various structures, and forms a catalyst system together with an organoboron-based cocatalyst to carry out ethylene oligomerization in situ. Therefore, without using high-valent alkylaluminoxanes such as methylaluminoxane (MAO) and modified methylaluminoxane (MMAO) conventionally used as cocatalysts, the activity and selectivity of the ethylene oligomerization reaction can be significantly improved to an excellent level, thereby enabling the preparation of 1-hexene and 1-octene in high yield, especially 1-octene. In addition, the formation of undesirable polymers, particularly polyethylene (PE) byproducts, is suppressed, and the ballooning effect is avoided, thus providing the advantage of enabling the large-scale production of ethylene oligomers. Detailed Implementation

[0107] The present invention will be described in detail below. Unless otherwise defined, the technical and scientific terms used have the meanings commonly understood by one of ordinary skill in the art to which this invention pertains, and descriptions of well-known functions and structures that may unnecessarily obscure the gist of the invention are omitted in the following description.

[0108] In this specification, unless the context otherwise requires, the expressions “comprising / including” and “included / including” shall be understood to cover the steps or components presented, or the group of steps or components, but do not exclude any other steps or components, or the group of steps or components.

[0109] In this specification, the terms "substituent", "radical", "group", "moiety" and "fragment" are used interchangeably.

[0110] In this specification, "C" A -C B "" refers to "the number of carbon atoms is A or more and B or less".

[0111] In this specification, "hydrocarbon group" or "heterohydrocarbon group" refers to a group derived from a hydrocarbon or heterohydrocarbon having a single bonding site, and "heterohydrocarbon" means that a carbon atom is replaced by one or more heteroatoms selected from O, S, Se, P, B and N atoms.

[0112] In this specification, "alkyl", "alkoxy" and other substituents containing the "alkyl" moiety include straight-chain and branched forms.

[0113] In this specification, "substituted" means a group or part having one or more substituents attached to the structural skeleton of the group or part. Without limitation, "substituted" means that the mentioned group or structural skeleton is substituted by one or more of the following: deuterium, hydroxyl, halogen, alkyl, haloalkyl, alkenyl, alkoxy, haloalkoxy, aryl, aryloxy, haloaryl, heterocyclic alkyl, carboxyl, cyano, nitro, alkylaryl, arylalkyl, arylalenyl, arylynyl, cycloalkyl, cycloalkylalkyl, cycloalkenyl, heteroaryl, heteroarylalkyl, -N(R')2, -Si(R'')3, -COR'', -OCOR'', -NHCOR'', and -SR', wherein each of R' is independently hydrogen, alkyl, alkenyl, alkynyl, or aryl, each of R' is independently hydrogen, alkyl, alkenyl, alkynyl, alkoxy, or aryl, and R'' is hydrogen, alkyl, alkenyl, alkynyl, aryl, or amino.

[0114] Specifically, "substituted" refers to substances selected from deuterium, hydroxyl groups, halogens, and C1-C atoms. 10 Alkyl, halogenated C1-C10 Alkyl, C2-C 10 alkenyl, C2-C 10 alkynyl group, C1-C 10 Alkoxy, halogenated C1-C 10 Alkoxy, C6-C 20 Aryl, C6-C 20 Aryloxy groups, halogenated C6-C 20 Aryl, 5- to 7-membered heterocyclic alkyl, carboxyl, cyano, nitro, C1-C 10 Alkyl C6-C 20 Aryl, C6-C 20 Aryl C1-C 10 Alkyl, C6-C 20 Aryl C2-C 10 alkenyl, C6-C 20 Aryl C2-C 10 alkynyl group, C3-C 10 cycloalkyl, C3-C 10 cycloalkyl C1-C 10 Alkyl, C3-C 10 Cycloalkenyl, C3-C 20 heteroaryl, C3-C 20 heteroaryl C1-C 10 The alkyl group, -N(R')2, -Si(R”)3, -COR”', -OCOR”', -NHCOR”', and -SR' are substituted with one or more of them, wherein each R' is independently hydrogen, C1-C 10 Alkyl, C2-C 10 alkenyl, C2-C 10 alkynyl or C6-C 20 The aryl group and R are each independently hydrogen, C1-C. 10 Alkyl, C2-C 10 alkenyl, C2-C 10 alkynyl group, C1-C 10 Alkyl or C6-C 20 Aryl group, where R”' is hydrogen, C1-C 10 Alkyl, C2-C 10 alkenyl, C2-C 10 alkynyl group, C1-C 10 Alkoxy, C6-C 20 Aryl or amino.

[0115] In this specification, "alkyl" refers to a monovalent straight-chain or branched saturated hydrocarbon group consisting only of carbon atoms and hydrogen atoms, including, but not limited to, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, hexyl, octyl, nonyl, etc. Furthermore, the alkyl groups described in this invention have 1-10 carbon atoms, preferably 1-7 carbon atoms, and more preferably 1-5 carbon atoms.

[0116] In this specification, "aryl" refers to a monovalent organic group derived from aromatic hydrocarbons by removing a hydrogen atom. As an example, it includes monocyclic or fused-ring systems containing 4-7 ring atoms, preferably 5 or 6 ring atoms, and includes multiple aryl groups linked by single bonds. Specific examples include phenyl, naphthyl, biphenyl, anthracene, indenyl, fluorenyl, etc., but are not limited thereto. Furthermore, the aryl groups described in this invention have 6-20 carbon atoms, preferably 6-12 carbon atoms.

[0117] In this specification, "halogenated" or "halogen" refers to fluorine, chlorine, bromine, or iodine atoms.

[0118] In this specification, "alkenyl" refers to a straight-chain or branched unsaturated hydrocarbon monovalent group containing one or more double bonds between two or more carbon atoms, specifically including vinyl, propenyl, 1-propen-2-yl, 1-butenyl, 2-butenyl, isobutenyl, 1-pentenyl, 2-pentenyl, 3-methyl-1-butenyl, 2-methyl-2-butenyl, 2,3-dimethyl-2-butenyl, etc., but not limited to these.

[0119] In this specification, "alkynyl" refers to a straight-chain or branched unsaturated hydrocarbon monovalent group containing one or more triple bonds between two or more carbon atoms, specifically including ethynyl, propynyl, 1-butynyl, 2-butynyl, 1-pentynyl, 2-pentynyl, 3-methyl-1-butynyl, etc., but not limited to these.

[0120] In this specification, "alkoxy" refers to an -O-alkyl group, where "alkyl" is the same as defined above. Examples of such alkoxy groups include, but are not limited to, methoxy, ethoxy, isopropoxy, butoxy, isobutoxy, tert-butoxy, etc.

[0121] In this specification, "aryloxy group" refers to an -O-aryl group, where "aryl" is the same as defined above. Examples of such aryloxy groups include phenoxy, naphthoxy, etc., but are not limited to these.

[0122] In this specification, "alkoxycarbonyl" refers to a -C(=O)alkoxy group, where "alkoxy" is the same as defined above. Examples of such alkoxycarbonyl groups include, but are not limited to, methoxycarbonyl, ethoxycarbonyl, isopropoxycarbonyl, propoxycarbonyl, butoxycarbonyl, isobutoxycarbonyl, tert-butoxycarbonyl, etc.

[0123] In this specification, "alkylcarbonyloxy" refers to an -OC (=O) alkyl group, where "alkyl" is the same as defined above. Examples of such alkylcarbonyloxy groups include, but are not limited to, methylcarbonyloxy, ethylcarbonyloxy, isopropylcarbonyloxy, propylcarbonyloxy, butylcarbonyloxy, isobutylcarbonyloxy, tert-butylcarbonyloxy, etc.

[0124] In this specification, "alkenyl carbonyloxy" refers to an -OC (=O) alkenyl group, where "alkenyl" is the same as defined above. Examples of such alkenyl carbonyloxy groups include vinyl carbonyloxy, butenyl carbonyloxy, etc., but are not limited to these.

[0125] In this specification, "alkynylcarbonyloxy" refers to the -OC (=O) alkynyl group, where "alkynyl" is the same as defined above. Examples of such alkynylcarbonyloxy groups include ethynylcarbonyloxy, butynylcarbonyloxy, etc., but are not limited to these.

[0126] In this specification, "cycloalkyl" refers to a monovalent saturated carbocyclic group consisting of one or more rings. Examples of cycloalkyl groups include, but are not limited to, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, and cycloheptyl.

[0127] In this specification, "heteroaryl" refers to a monovalent heteroaryl group, which is an aryl group containing 1-4 heteroatoms selected from N, O, and S as the aromatic ring skeleton atoms, and the remaining aromatic ring skeleton atoms are carbon. The heteroaryl is a 5- to 6-membered monocyclic heteroaryl and a polycyclic heteroaryl fused to one or more benzene rings, and may be partially saturated. Furthermore, the heteroaryl in this invention also includes a form in which one or more heteroaryl groups are linked by single bonds. Examples of heteroaryl groups include, but are not limited to, pyrroleyl, pyrazolyl, quinolinyl, isoquinolinyl, pyridinyl, pyrimidinyl, oxazolyl, thiazolyl, thiadiazolyl, triazolyl, imidazoleyl, benzimidazolyl, isoxazolyl, benzisoxazolyl, thiophenyl, benzothiophenyl, furanyl, and benzofuranyl.

[0128] In this specification, "heterocyclic alkyl" is a monovalent group comprising 1 to 4 heteroatoms selected from N, O, and S, of a 5- to 7-membered non-aromatic heterocycle, including saturated or unsaturated monocyclic forms, and which can be bonded by heteroatoms or carbon atoms. Examples of such heterocyclic alkyl groups may include monovalent groups of non-aromatic heterocycles such as pyrrolidine, piperidine, tetrahydropyridine, piperazine, morpholine, and thiomorpholine.

[0129] In this specification, alkyl or alkoxy groups may have 1-10 carbon atoms, preferably 1-7 carbon atoms, more preferably 1-5 carbon atoms; alkenyl or alkynyl groups may have 2-10 carbon atoms, preferably 2-7 carbon atoms, more preferably 2-5 carbon atoms; aryl groups may have 6-20 carbon atoms, preferably 6-12 carbon atoms; and heteroaryl groups may have 3-20 carbon atoms, preferably 3-12 carbon atoms.

[0130] In this specification, "ethylene oligomerization" refers to the oligomerization of ethylene, and is referred to as trimerization or tetramerization depending on the amount of ethylene polymerized. Specifically, in this specification, "ethylene oligomerization" refers to 1-hexene, 1-octene, or mixtures thereof prepared from ethylene as the main comonomer of LLDPE.

[0131] In this specification, "oligopolymer catalyst" is defined not only as a chromium complex with heteroatom ligands, but also as a mixture of chromium catalyst precursors and heteroatom ligands.

[0132] In this specification, "oligopolymer catalyst system" is defined as a "oligopolymer catalyst" that further includes a co-catalyst and / or additives.

[0133] The inventors discovered that when a chromium catalyst precursor formed using low-valent reactants in a specific reaction sequence is applied together with an organoboron-based co-catalyst to the ethylene oligomerization reaction, it achieves the same level of high activity as existing oligomerization catalyst systems that use large amounts of high-valent methylaluminoxane (MAO) or modified methylaluminoxane (MMAO), and selectively forms 1-octene and 1-hexene, thus completing this invention.

[0134] This invention provides a precursor for an ethylene oligomerization catalyst that enables ethylene to oligomerize with high activity and selectivity even without the use of methylaluminoxane (MAO) or modified methylaluminoxane (MMAO). The catalyst precursor of this invention can be a chromium catalyst precursor represented by the following chemical formula 1:

[0135] [Chemical Formula 1] [CrM 1 (L) x (R) 6-x ] n (w) m

[0136] In the chemical formula 1,

[0137] M 1 It is a Group 13 element;

[0138] L is a ligand in the form of a β-ketoenol salt;

[0139] R is a halogen, C1-C 10 Alkyl or C6-C 20 aryloxy;

[0140] W is a neutral coordinating ligand;

[0141] n is an integer of 1 or 2;

[0142] x is an integer from 1 to 6;

[0143] m is an integer from 0 to 4.

[0144] The chromium catalyst precursor of Formula 1 can be a chromium(III) precursor represented by Cr(L)3 and a precursor represented by M. 1 (R)3 represents the reaction products of Lewis acids containing Group 13 elements, and their reactions can be carried out in an inert solvent. That is, the chromium catalyst precursor can be prepared from readily available, low-cost raw materials and exist in a homogeneous solution phase. Specifically, the inert solvent can be a nitrile solvent with 2 to 30 carbon atoms, a cyclic or acyclic ether solvent with 2 to 30 carbon atoms, water (H2O), or a hydrocarbon solvent containing water. More specifically, it can be acetonitrile (ACN), tetrahydrofuran (THF), diethyl ether, water (H2O), or chlorobenzene, toluene, etc., containing a small amount of water.

[0145] Specifically, the chromium catalyst precursor may be the product of reacting a chromium(III) precursor and a Lewis acid containing a Group 13 element in an inert solvent in the same equivalence ratio.

[0146] The chromium catalyst precursor can exist in a homogeneous solution phase, thus exhibiting excellent long-term storage stability. Subsequently, it can be used as an ethylene oligomerization catalyst together with heteroatom ligands and activated by an organoboron-based co-catalyst, thereby maintaining stable catalytic activity during oligomerization. It also has the advantage of being easy to apply in continuous processes.

[0147] In one embodiment of the chromium catalyst precursor, the chromium catalyst precursor of chemical formula 1 may be mononuclear or binuclear.

[0148] In one embodiment of the chromium catalyst precursor, the chromium catalyst precursor of chemical formula 1 may comprise a mononuclear form represented by the following chemical formula 1-1.

[0149] [Chemical Formula 1-1] CrM 1 (L) x (R) 6-x

[0150] In the chemical formula 1-1, M1 L and R are defined as in the chemical formula 1.

[0151] In one embodiment of the chromium catalyst precursor, the chromium catalyst precursor of chemical formula 1 may comprise a binuclear form represented by the following chemical formulas 1-2.

[0152] [Chemical Formula 1-2] [Cr2(L)2(R)2] 2+ [M 1 (R)2(L)2] - 2(W) m

[0153] In chemical formulas 1-2, M 1 L, R, W and m are the same as defined in Chemical Formula 1.

[0154] In a chromium catalyst precursor according to one embodiment, the M 1 It can be boron (B) or aluminum (Al).

[0155] In a chromium catalyst precursor according to one embodiment, L can be an enol ligand represented by the following chemical formula A.

[0156] [Chemical Formula A]

[0157] In the chemical formula A,

[0158] R 1 and R 3 Each can be independently a halogen, a hydrocarbon group, a substituted hydrocarbon group, a heterohydrocarbon group, or a substituted heterohydrocarbon group;

[0159] R 2 It can be hydrogen, halogen, hydrocarbon group, substituted hydrocarbon group, heterohydrocarbon group or substituted heterohydrocarbon group;

[0160] The R 1 and R 2 , or R 3 and R 2 A ring can be formed by linking alkylene groups, substituted alkylene groups, heteroalkylene groups, or substituted heteroalkylene groups.

[0161] In a chromium catalyst precursor according to one embodiment, W is derived from the generation of chromium acetylacetone (III) and M. 1 (R)3 represents an inert solvent for the reaction of Lewis acids containing Group 13 elements, preferably a nitrile having 2 to 30 carbon atoms, a cyclic or acyclic ether having 2 to 30 carbon atoms, or water (H2O), more preferably acetonitrile (ACN), tetrahydrofuran (THF), diethyl ether, or water (H2O).

[0162] Preferably, in the chromium catalyst precursor according to one embodiment, the M 1 It can be boron (B) or aluminum (Al); R can be halogen or C1-C. 10 Alkoxy; W can be acetonitrile (ACN), tetrahydrofuran (THF), diethyl ether or water (H2O); m can be an integer from 2 to 4; x can be an integer from 1 to 6; L can be an acetylacetone ligand with the following structure.

[0163] (R 1 and R 3 Each independently is C1-C 10 Alkyl or C6-C 20 Aryl, the R 1 and R 3 The alkyl and aryl groups can be further selected from halogens, C1-C... 10 Alkyl, C6-C 20 Aryl, halogenated C1-C 10 Alkyl and halogenated C6-C 20 One or more substituents are substituted in the aryl group;

[0164] R 2 Hydrogen, halogen, C1-C 10 Alkyl or C6-C 20 Aryl, the R 2 The alkyl and aryl groups can be further selected from halogens, C1-C... 10 Alkyl, C6-C 20 Aryl, halogenated C1-C 10 Alkyl and halogenated C6-C 20 One or more of the aryl groups are substituted;

[0165] The R 1 and R 2 , or R 3 and R 2 Through C3-C 10 Alkylene, C3-C 10 alkenyl, C6-C 20 aryl, C3-C 10 Heteroalkylene, C3-C 10 Heteroene or C6-C 20 (The heteroarylene groups connect to form a ring.)

[0166] More preferably, in the chromium catalyst precursor according to one embodiment, the M 1 It can be boron (B); L can be acetylacetone salt; R can be C1-C 10Alkoxy group; W can be acetonitrile (ACN), tetrahydrofuran (THF), diethyl ether, or water (H2O); m can be an integer from 2 to 4; x can be an integer from 1 to 6.

[0167] More preferably, in the chromium catalyst precursor according to one embodiment, the M 1 It can be aluminum (Al); L can be acetylacetonate; R can be halogen; W can be acetonitrile (ACN), tetrahydrofuran (THF), diethyl ether or water (H2O); m can be an integer from 2 to 4; x can be an integer from 1 to 6.

[0168] Furthermore, the present invention provides an ethylene oligomerization catalyst comprising a chromium catalyst precursor represented by the aforementioned chemical formula 1 and a heteroatom ligand.

[0169] According to one embodiment, the ethylene oligomerization catalyst has a structure comprising a chromium catalyst precursor of Formula 1 and a heteroatom ligand, specifically CrM 1 (L) x (R) 6-x (L')(w) m It means that the M 1 It can be a group 13 element; L can be a ligand in the form of a β-ketoenol salt; R can be a halogen, C1-C 10 Alkyl or C6-C 20 Aryloxy group; L' can be a heteroatom ligand; W can be a neutral coordinating ligand; m can be an integer from 0 to 4.

[0170] The chromium catalyst precursor of Formula 1 can be a chromium(III) precursor represented by Cr(L)3 and a precursor represented by M. 1 (R)3 represents the reaction products of Lewis acids containing Group 13 elements, and their reactions can be carried out in an inert solvent. That is, the chromium catalyst precursor can be prepared from readily available, low-cost raw materials and exist in a homogeneous solution phase. Specifically, the inert solvent can be a nitrile solvent with 2 to 30 carbon atoms, a cyclic or acyclic ether solvent with 2 to 30 carbon atoms, water (H2O), or a hydrocarbon solvent containing water. More specifically, it can be acetonitrile (ACN), tetrahydrofuran (THF), diethyl ether, water (H2O), or chlorobenzene, toluene, etc., containing a small amount of water.

[0171] Specifically, the chromium catalyst precursor is the product of reacting a chromium(III) precursor and a Lewis acid containing a Group 13 element in an inert solvent at the same stoichiometric ratio, and can exist in a homogeneous solution phase. An ethylene oligomerization catalyst according to one embodiment can be obtained by mixing and reacting heteroatom ligands of various structures without separate separation and purification processes. The obtained ethylene oligomerization catalyst can be directly mixed with a co-catalyst without separate separation and purification processes and applied in-situ to the ethylene oligomerization reaction.

[0172] According to one embodiment, the ethylene oligomerization catalyst can be prepared by reacting a chromium catalyst precursor of Formula 1 with heteroatom ligands of various structures. The heteroatom ligands can be organic compounds having two atoms that can coordinate with chromium, such as those having two atoms selected from phosphorus (P), arsenic (As), antimony (Sb), oxygen (O), bismuth (Bi), sulfur (S), selenium (Se), nitrogen (N), etc.

[0173] In one embodiment of the ethylene oligomerization catalyst, the heteroatom ligand may be a phosphine ligand represented by the following chemical formula 3, comprising two phosphorus (P) atoms.

[0174] [Chemical Formula 3] (R 12 (R) 11 PYZ

[0175] In the chemical formula 3

[0176] R 11 and R 12 Each can be independently a hydrocarbon group, a heterohydrocarbon group, a substituted hydrocarbon group, or a substituted heterohydrocarbon group;

[0177] Y is the linking group between P and Z;

[0178] Z is *-P(R) 13 (R) 14 )or

[0179] Ring A and ring B are each an aromatic ring independently;

[0180] L 1 and L 2 Each can be independently a single bond, a heteroatom, a substituted heteroatom, -C(=O)- or -CR'R”-;

[0181] R' and R” can each be hydrogen, hydrocarbon group, substituted hydrocarbon group, heterohydrocarbon group or substituted heterohydrocarbon group independently;

[0182] R 13 To R 16Each can be independently a hydrocarbon group, a heterohydrocarbon group, a substituted hydrocarbon group, or a substituted heterohydrocarbon group;

[0183] c and d are each independent integers from 0 to 4.

[0184] When an ethylene oligomerization catalyst composed of a chromium catalyst precursor of Formula 1 and a phosphine ligand of Formula 3 is applied to the selective oligomerization reaction of ethylene, superior activity and selectivity (selectivity for 1-hexene and 1-octene) can be achieved.

[0185] In one embodiment of the ethylene oligomerization catalyst, in the heteroatom ligand of formula 3, Y can be an alkylene group, -N(R) group, or a hydrocarbon group. 21 )-、-N(R 21 )-N(R 22 )-、=C(R 23 )-N(R 21 )-、-N(R 21 )-C(R 23 (R) 24 - or -N(R) 21 )-L 3 -N(R 22 )-;R 21 To R 24 It can be independently hydrogen, a hydrocarbon group, a substituted hydrocarbon group, a heterohydrocarbon group, a substituted heterohydrocarbon group, or a substituted heteroatom; L 3 It can be a hydrocarbon group.

[0186] Preferably, in the chemical formula 3, Y can be -N(R) 21 )-, R 21 It can be a hydrocarbon group, a substituted hydrocarbon group, a heterohydrocarbon group, a substituted heterohydrocarbon group, or a substituted heteroatom.

[0187] In an ethylene oligomerization catalyst according to one embodiment, the heteroatom ligand of Formula 3 is preferably a heteroatom ligand with a PNP framework structure represented by Formula 4 or Formula 5.

[0188] [Chemical Formula 4]

[0189] [Chemical Formula 5]

[0190] In chemical formulas 4 and 5,

[0191] Rings A and B are each independently C6-C 20 Aromatic rings;

[0192] R 11 To R 14 R15 and R 16 Each independently is C6-C 20 Aryl, C6-C 20 Aryl C1-C 10 Alkyl, C6-C 20 Aryl C2-C 10 alkenyl, C6-C 20 Aryl C2-C 10 alkynyl group, C1-C 10 Alkyl, C2-C 10 alkenyl, C2-C 10 alkynyl group, C1-C 10 Alkoxy, C6-C 20 aryloxy group, C1-C 10 alkoxycarbonyl, C1-C 10 Alkyl carbonyl group, C2-C 10 alkenyl carbonyl group, C2-C 10 alkynyl carbonyl group, amino carbonyl group, C1-C 10 Alkyl carbonyl amino, C2-C 10 alkenyl carbonyl amino, C2-C 10 alkynyl carbonyl amino, C3-C 10 Cycloalkyl, mercapto C1-C 10 Alkyl, mercapto C2-C 10 alkenyl, mercapto C2-C 10 alkynyl group, C3-C 20 Heteroaryl, 5- to 7-membered heterocyclic alkyl, -NR a1 R b1 or -SiR c1 R d1 R e1 ;

[0193] R a1 and R b1 Each independently is hydrogen, C1-C 10 Alkyl, C2-C 10 alkenyl, C2-C 10 alkynyl group, C6-C 20 Aryl, C1-C 10 Alkylamino, C2-C 10 alkenyl amino or C2-C 10 alkynylamino;

[0194] R c1 For C1-C 10 Alkyl, C2-C 10 alkenyl, C2-C 10 alkynyl or C6-C 20 Aryl;

[0195] Rd1 and R e1 Each independently is hydrogen, C1-C 10 Alkyl, C2-C 10 alkenyl, C2-C 10 alkynyl or C6-C 20 Aryl;

[0196] R 21 For C1-C 10 Alkyl, C2-C 10 alkenyl, C2-C 10 alkynyl group, C6-C 20 Aryl, C6-C 20 Aryl C1-C 10 Alkyl, C6-C 20 Aryl C2-C 10 alkenyl, C6-C 20 Aryl C2-C 10 alkynyl group, C3-C 10 cycloalkyl, C3-C 20 Heteroaryl, 5- to 7-membered heterocyclic alkyl, C1-C 10 Alkoxy, C6-C 20 aryloxy group, C1-C 10 alkoxycarbonyl, C1-C 10 Alkyl carbonyl group, C2-C 10 alkenyl carbonyl group, C2-C 10 alkynyl carbonyl group, amino carbonyl group, C1-C 10 Alkyl carbonyl amino, C2-C 10 alkenyl carbonyl amino, C2-C 10 alkynyl carbonyl amino, -NR a2 R b2 or -SiR c2 R d2 R e2 ;

[0197] L 1 and L 2 Each can be independently a single bond, -O-, -S-, -NR'-, -P(=O)R'-, -P(=Se)R'-, -P(=S)R'-, -SiR'R”-, -CR'R”-, or -C(=O)-;

[0198] R' and R” are each independently hydrogen, C1-C 10 Alkyl, C2-C 10 alkenyl, C2-C 10 alkynyl group, C6-C 20 Aryl, C6-C 20 Aryl C1-C 10 Alkyl, C6-C 20Aryl C2-C 10 alkenyl, C6-C 20 Aryl C2-C 10 alkynyl group, C3-C 10 cycloalkyl, C3-C 20 Heteroaryl, 5- to 7-membered heterocyclic alkyl, C1-C 10 Alkoxy, C6-C 20 aryloxy group, C1-C 10 alkoxycarbonyl, C1-C 10 Alkyl carbonyl group, C2-C 10 alkenyl carbonyl group, C2-C 10 alkynyl carbonyl group, amino carbonyl group, C1-C 10 Alkyl carbonyl amino, C2-C 10 alkenyl carbonyl amino, C2-C 10 alkynyl carbonyl amino, -NR a3 R b3 or -SiR c3 R d3 R e3 ;

[0199] R a2 R b2 R a3 and R b3 Each independently is hydrogen, C1-C 10 Alkyl, C2-C 10 alkenyl, C2-C 10 alkynyl or C6-C 20 Aryl;

[0200] R c2 and R c3 Each independently is C1-C 10 Alkyl, C2-C 10 alkenyl, C2-C 10 alkynyl or C6-C 20 Aryl;

[0201] R d2 R e2 R d3 and R e3 Each independently is hydrogen, C1-C 10 Alkyl, C2-C 10 alkenyl, C2-C 10 alkynyl or C6-C 20 Aryl;

[0202] c and d are each independent integers from 0 to 4;

[0203] The R 11 To R 14 R 15and R 16 aryl, arylalkyl, alkyl, arylalenyl, alkenyl, arylynyl, alkoxy, aryloxy, cycloalkyl, heteroaryl or heterocycloalkyl and R 21 The alkyl, alkenyl, aryl, arylalkyl, arylalkenyl, arylynyl, cycloalkyl, heteroaryl, heterocycloalkyl, alkoxy, aryloxy, alkoxycarbonyl, alkylcarbonyloxy, alkenylcarbonyloxy, alkynylcarbonyloxy, aminocarbonyl, alkylcarbonylamino, alkenylcarbonylamino, or alkynylcarbonylamino groups of R' and R" may be further selected from halogens, C1-C 10 Alkyl, halogenated C1-C 10 Alkyl, C2-C 10 alkenyl, C2-C 10 alkynyl group, C1-C 10 Alkoxy, halogenated C1-C 10 Alkoxy, C6-C 20 Aryl, C6-C 20 Aryloxy, 5- to 7-membered heterocyclic alkyl, -NR a4 R b4 and -SiR c4 R d4 R e4 One or more substitutions in; R a4 and R b4 Each independently is hydrogen, C1-C 10 Alkyl, C2-C 10 alkenyl, C2-C 10 alkynyl or C6-C 20 Aryl, R c4 To R e4 Each independently is C1-C 10 Alkyl or C1-C 10 Alkyl group.

[0204] In an ethylene oligomerization catalyst according to one embodiment, the L in the heteroatom ligands of formulas 3 and 5 1 and L 2 Each can be a single bond or -O- independently.

[0205] Specifically, in chemical formulas 4 and 5, ring A and ring B are each independently C6-C. 20 Aromatic rings; R 11 To R 14 R 15 and R 16 Each independently is C6-C 20 Aryl, C6-C 20 Aryl C1-C 10 Alkyl, C1-C 10 Alkyl, C2-C 10 alkenyl, C2-C10 alkynyl group, C1-C 10 Alkoxy, C6-C 20 Aryloxy group, C3-C 10 Cycloalkyl, mercapto C1-C 10 Alkyl, C3-C 20 Heteroaryl, 5- to 7-membered heterocyclic alkyl, -NR a1 R b1 or -SiR c1 R d1 R e1 ;R a1 and R b1 Each independently is hydrogen, C1-C 10 Alkyl, C6-C 20 Aryl or C1-C 10 Alkylamino; R c1 R d1 and R e1 Each independently is C1-C 10 Alkyl or C6-C 20 Aryl; R 21 For C1-C 10 Alkyl, C2-C 10 alkenyl, C2-C 10 alkynyl group, C6-C 20 Aryl, C6-C 20 Aryl C1-C 10 Alkyl, C3-C 10 cycloalkyl, C3-C 20 Heteroaryl, 5- to 7-membered heterocyclic alkyl, C1-C 10 Alkoxy, C6-C 20 aryloxy group, -NR a2 R b2 or -SiR c2 R d2 R e2 ;R a2 and R b2 Each is independently hydrogen or C1-C 10 Alkyl; R c2 For C1-C 10 Alkyl or C6-C 20 Aryl; R d2 and R e2 Each independently is hydrogen, C1-C 10 Alkyl or C6-C 20 Aryl; L 1 and L 2 Each is independently a single bond or -O-; c and d are each independently an integer from 0 to 4; the R 11 To R 14 R 15 and R16 aryl, arylalkyl, alkyl, alkenyl, alkoxy, aryloxy, cycloalkyl, heteroaryl or heterocycloalkyl and R 21 The alkyl, alkenyl, alkynyl, aryl, arylalkyl, cycloalkyl, heteroaryl, heterocycloalkyl, alkoxy, or aryloxy groups may be further selected from halogens, C1-C... 10 Alkyl, halogenated C1-C 10 Alkyl, C2-C 10 alkenyl, C2-C 10 alkynyl group, C1-C 10 Alkoxy, halogenated C1-C 10 Alkoxy, C6-C 20 Aryl, C6-C 20 Aryloxy, 5- to 7-membered heterocyclic alkyl, -NR a4 R b4 and -SiR c4 R d4 R e4 One or more substitutions in; R a4 and R b4 Each independently is hydrogen, C1-C 10 Alkyl or C6-C 20 Aryl, R c4 To R e4 Each can be independently C1-C 10 Alkyl or C1-C 10 Alkyl group.

[0206] Preferably, in chemical formulas 4 and 5 according to one embodiment, ring A and ring B are each independently C6-C. 20 Aromatic rings; R 11 To R 14 Each independently is C6-C 20 Aryl, C6-C 20 Aryl C1-C 10 Alkyl, C3-C 10 cycloalkyl or C3-C 20 heteroaryl; R 15 and R 16 Each independently is C6-C 20 Aryl, C6-C 20 Aryl C1-C 10 Alkyl, C1-C 10 Alkyl, C2-C 10 alkenyl, C2-C 10 alkynyl group, C3-C 10 Cycloalkyl, mercapto C1-C 10 Alkyl, C3-C 20 Heteroaryl, 5- to 7-membered heterocyclic alkyl; R 21 For C1-C10 Alkyl, C2-C 10 alkenyl, C2-C 10 alkynyl group, C6-C 20 Aryl, C6-C 20 Aryl C1-C 10 Alkyl or C3-C 10 cycloalkyl; L 1 and L 2 Each is independently a single bond or -O-; c and d are each independently an integer from 0 to 4; the R 11 To R 14 aryl, arylalkyl, alkyl, cycloalkyl or heteroaryl, R 15 and R 16 aryl, arylalkyl, alkyl, alkenyl, ynyl, cycloalkyl, heteroaryl or heterocycloalkyl and R 21 The alkyl, alkenyl, alkynyl, aryl, arylalkyl, or cycloalkyl groups may be further selected from halogens, C1-C... 10 Alkyl, halogenated C1-C 10 Alkyl, C1-C 10 Alkoxy, halogenated C1-C 10 Alkoxy, C6-C 20 Aryl, C6-C 20 aryloxy, 5- to 7-membered heterocyclic alkyl, amino, single or di-C1-C 10 Alkylamino, tri-C1-C 10 Alkyl silyl, diC1-C 10 alkylarylsilyl, C1-C 10 Alkyl diC6-C 20 Arylsilyl, tri-C1-C 10 Alkoxysilyl and tri-C6-C 20 One or more of the arylsilyl groups are substituted.

[0207] More preferably, in chemical formulas 4 and 5 according to one embodiment, ring A and ring B are each independently C6-C. 20 Aromatic rings; R 11 To R 14 Each independently is C6-C 20 Aryl; R 15 and R 16 Each independently is C1-C 10 Alkyl; R 21 For C1-C 10 Alkyl or C3-C 10 cycloalkyl; L 1 and L 2 Each is independently a single bond or -O-; c and d are each independently an integer of 0 or 1; the R 11 To R14 The aryl group can be further selected from halogens, C1-C 10 Alkyl, halogenated C1-C 10 Alkyl, C1-C 10 Alkoxy, halogenated C1-C 10 Alkoxy, C6-C 20 Aryl, C6-C 20 Aryloxy, 5- to 7-membered heterocyclic alkyl, three C1-C 10 Alkyl silyl, diC1-C 10 alkylarylsilyl, C1-C 10 Alkyl diC6-C 20 Arylsilyl, tri-C1-C 10 Alkoxysilyl and tri-C6-C 20 One or more of the arylsilyl groups are substituted.

[0208] In one specific implementation, in chemical formula 5, the L 1 and L 2 Both can be single keys.

[0209] In one specific implementation, in chemical formula 5, the L 1 It can be a single bond, the L 2 It can be -O-.

[0210] In one specific implementation, in chemical formula 5, ring A and ring B can each be independently benzene or naphthalene.

[0211] In an ethylene oligomerization catalyst according to one embodiment, the heteroatom ligand of Formula 5 is preferably a heteroatom ligand with a PNP framework structure represented by Formula 6.

[0212] [Chemical Formula 6]

[0213] In the chemical formula 6,

[0214] R 11 and R 12 Each independently is C6-C 20 Aryl, C6-C 20 Aryl C1-C 10 Alkyl, C6-C 20 Aryl C2-C 10 alkenyl, C6-C 20 Aryl C2-C 10 alkynyl group, C1-C 10 Alkyl, C2-C 10 alkenyl, C2-C 10 alkynyl group, C1-C10 Alkoxy, C6-C 20 aryloxy group, C1-C 10 alkoxycarbonyl, C1-C 10 Alkyl carbonyl group, C2-C 10 alkenyl carbonyl group, C2-C 10 alkynyl carbonyl group, amino carbonyl group, C1-C 10 Alkyl carbonyl amino, C2-C 10 alkenyl carbonyl amino, C2-C 10 alkynyl carbonyl amino, C3-C 10 Cycloalkyl, mercapto C1-C 10 Alkyl, mercapto C2-C 10 alkenyl, mercapto C2-C 10 alkynyl group, C3-C 20 Heteroaryl, 5- to 7-membered heterocyclic alkyl, -NR a1 R b1 or -SiR c1 R d1 R e1 ;

[0215] R a1 and R b1 Each independently is hydrogen, C1-C 10 Alkyl, C2-C 10 alkenyl, C2-C 10 alkynyl group, C6-C 20 Aryl, C1-C 10 Alkylamino, C2-C 10 alkenyl amino or C2-C 10 alkynylamino;

[0216] R c1 For C1-C 10 Alkyl, C2-C 10 alkenyl, C2-C 10 alkynyl or C6-C 20 Aryl;

[0217] R d1 and R e1 Each independently is hydrogen, C1-C 10 Alkyl, C2-C 10 alkenyl, C2-C 10 alkynyl or C6-C 20 Aryl;

[0218] R 21 For C1-C 10 Alkyl, C2-C 10 alkenyl, C2-C 10 alkynyl group, C6-C 20 Aryl, C6-C20 Aryl C1-C 10 Alkyl, C6-C 20 Aryl C2-C 10 alkenyl, C6-C 20 Aryl C2-C 10 alkynyl group, C3-C 10 cycloalkyl, C3-C 20 Heteroaryl, 5- to 7-membered heterocyclic alkyl, C1-C 10 Alkoxy, C6-C 20 aryloxy group, C1-C 10 alkoxycarbonyl, C1-C 10 Alkyl carbonyl group, C2-C 10 alkenyl carbonyl group, C2-C 10 alkynyl carbonyl group, amino carbonyl group, C1-C 10 Alkyl carbonyl amino, C2-C 10 alkenyl carbonyl amino, C2-C 10 alkynyl carbonyl amino, -NR a2 R b2 or -SiR c2 R d2 R e2 ;

[0219] R a2 and R b2 Each independently is hydrogen, C1-C 10 Alkyl, C2-C 10 alkenyl, C2-C 10 alkynyl or C6-C 20 Aryl;

[0220] R c2 For C1-C 10 Alkyl, C2-C 10 alkenyl, C2-C 10 alkynyl or C6-C 20 Aryl;

[0221] R d2 and R e2 Each independently is hydrogen, C1-C 10 Alkyl, C2-C 10 alkenyl, C2-C 10 alkynyl or C6-C 20 Aryl;

[0222] The C ring and D ring are each independently benzene or naphthalene;

[0223] R 22 and R 23 Hydrogen, C1-C 10 Alkyl, C6-C 20 Aryl, C3-C10 cycloalkyl, C6-C 20 Aryl C1-C 10 Alkyl or C1-C 10 Alkyl C6-C 20 Aryl;

[0224] The R 11 and R 12 aryl, arylalkyl, alkyl, arylalenyl, alkenyl, arylynyl, alkoxy, aryloxy, cycloalkyl, heteroaryl, heterocycloalkyl and R 21 The alkyl, alkenyl, aryl, arylalkyl, arylalkenyl, arylynyl, cycloalkyl, heteroaryl, heterocycloalkyl, alkoxy, aryloxy, alkoxycarbonyl, alkylcarbonyloxy, alkenylcarbonyloxy, alkynylcarbonyloxy, aminocarbonyl, alkylcarbonylamino, alkenylcarbonylamino, or alkynylcarbonylamino can be further selected from halogens, C1-C 10 Alkyl, halogenated C1-C 10 Alkyl, C2-C 10 alkenyl, C2-C 10 alkynyl group, C1-C 10 Alkoxy, halogenated C1-C 10 Alkoxy, C6-C 20 Aryl, C6-C 20 Aryloxy, 5- to 7-membered heterocyclic alkyl, -NR a4 R b4 and -SiR c4 R d4 R e4 One or more substitutions in; R a4 and R b4 Each independently is hydrogen, C1-C 10 Alkyl, C2-C 10 alkenyl, C2-C 10 alkynyl or C6-C 20 Aryl, R c4 To R e4 Each independently is C1-C 10 Alkyl or C1-C 10 Alkyl group.

[0225] In an ethylene oligomerization catalyst according to one embodiment, the heteroatom ligand of Formula 6 is preferably a heteroatom ligand with a PNP framework structure represented by Formula 7 or Formula 8.

[0226] [Chemical Formula 7]

[0227] [Chemical Formula 8]

[0228] In chemical formulas 7 and 8,

[0229] R 11 and R 12 Each independently is C6-C 20 Aryl, C6-C 20 Aryl C1-C 10 Alkyl, C1-C 10 Alkyl, C2-C 10 alkenyl, C2-C 10 alkynyl group, C1-C 10 Alkoxy, C6-C 20 Aryloxy group, C3-C 10 Cycloalkyl, mercapto C1-C 10 Alkyl, C3-C 20 Heteroaryl, 5- to 7-membered heterocyclic alkyl, -NR a1 R b1 or -SiR c1 R d1 R e1 ;

[0230] R a1 and R b1 Each independently is hydrogen, C1-C 10 Alkyl, C6-C 20 Aryl or C1-C 10 Alkylamino;

[0231] R c1 R d1 and R e1 Each independently is C1-C 10 Alkyl or C6-C 20 Aryl;

[0232] R 21 For C1-C 10 Alkyl, C2-C 10 alkenyl, C2-C 10 alkynyl group, C6-C 20 Aryl, C6-C 20 Aryl C1-C 10 Alkyl, C3-C 10 cycloalkyl, C3-C 20 Heteroaryl, 5- to 7-membered heterocyclic alkyl, C1-C 10 Alkoxy, C6-C 20 aryloxy group, -NR a2 R b2 or -SiR c2 R d2 R e2 ;

[0233] Ra2 and R b2 Each is independently hydrogen or C1-C 10 alkyl;

[0234] R c2 For C1-C 10 Alkyl or C6-C 20 Aryl;

[0235] R d2 and R e2 Each independently is hydrogen, C1-C 10 Alkyl or C6-C 20 Aryl;

[0236] R 22 and R 23 Hydrogen, C1-C 10 Alkyl, C6-C 20 Aryl, C3-C 10 cycloalkyl, C6-C 20 Aryl C1-C 10 Alkyl or C1-C 10 Alkyl C6-C 20 Aryl;

[0237] The R 11 and R 12 aryl, arylalkyl, alkyl, alkenyl, alkoxy, aryloxy, cycloalkyl, heteroaryl or heterocycloalkyl and R 21 The alkyl, alkenyl, alkynyl, aryl, arylalkyl, cycloalkyl, heteroaryl, heterocycloalkyl, alkoxy, or aryloxy groups may be further selected from halogens, C1-C... 10 Alkyl, halogenated C1-C 10 Alkyl, C2-C 10 alkenyl, C2-C 10 alkynyl group, C1-C 10 Alkoxy, halogenated C1-C 10 Alkoxy, C6-C 20 Aryl, C6-C 20 Aryloxy, 5- to 7-membered heterocyclic alkyl, -NR a4 R b4 and -SiR c4 R d4 R e4 One or more substitutions in; R a4 and R b4 Each independently is hydrogen, C1-C 10 Alkyl or C6-C 20 Aryl, R c4 To R e4 Each can be independently C1-C 10 Alkyl or C1-C10 Alkyl group.

[0238] Preferably, in chemical formulas 7 and 8 according to one embodiment, R 11 and R 12 Each independently is C6-C 20 Aryl, C6-C 20 Aryl C1-C 10 Alkyl, C3-C 10 cycloalkyl or C3-C 20 heteroaryl; R 21 For C1-C 10 Alkyl, C2-C 10 alkenyl, C2-C 10 alkynyl group, C6-C 20 Aryl, C6-C 20 Aryl C1-C 10 Alkyl or C3-C 10 cycloalkyl; R 22 and R 23 Hydrogen, C1-C 10 Alkyl, C6-C 20 Aryl, C3-C 10 cycloalkyl, C6-C 20 Aryl C1-C 10 Alkyl or C1-C 10 Alkyl C6-C 20 Aryl; the R 11 and R 12 aryl, arylalkyl, alkyl, cycloalkyl or heteroaryl and R 21 The alkyl, alkenyl, alkynyl, aryl, arylalkyl, or cycloalkyl groups may be further selected from halogens, C1-C... 10 Alkyl, halogenated C1-C 10 Alkyl, C1-C 10 Alkoxy, halogenated C1-C 10 Alkoxy, C6-C 20 Aryl, C6-C 20 aryloxy, 5- to 7-membered heterocyclic alkyl, amino, single or di-C1-C 10 Alkylamino, tri-C1-C 10 Alkyl silyl, diC1-C 10 alkylarylsilyl, C1-C 10 Alkyl diC6-C 20 Arylsilyl, tri-C1-C 10 Alkoxysilyl and tri-C6-C 20 One or more of the arylsilyl groups are substituted.

[0239] More preferably, in chemical formulas 7 and 8 according to one embodiment, R11 and R 12 Each independently is C6-C 20 Aryl; R 21 For C1-C 10 Alkyl or C3-C 10 cycloalkyl; R 22 and R 23 It is hydrogen or C1-C 10 Alkyl; the R 11 and R 12 The aryl group can be further selected from halogens, C1-C 10 Alkyl, halogenated C1-C 10 Alkyl, C1-C 10 Alkoxy, halogenated C1-C 10 Alkoxy, C6-C 20 Aryl, C6-C 20 Aryloxy, 5- to 7-membered heterocyclic alkyl, three C1-C 10 Alkyl silyl, diC1-C 10 alkylarylsilyl, C1-C 10 Alkyl diC6-C 20 Arylsilyl, tri-C1-C 10 Alkoxysilyl and tri-C6-C 20 One or more of the arylsilyl groups are substituted.

[0240] In a more preferred aspect, with further enhanced catalytic activity and ethylene oligomer selectivity, according to formulas 7 and 8 of one embodiment, R 11 and R 12 Each can be independently defined as a C1-C 10 Alkyl silyl substituted C6-C 20 Aryl.

[0241] In an ethylene oligomerization catalyst according to one embodiment, the chromium catalyst precursor has chemical formula 1, M 1 It can be boron (B) or aluminum (Al); R can be halogen or C1-C. 10 Alkyl group; W can be acetonitrile (ACN), tetrahydrofuran (THF), diethyl ether or water (H2O); m can be an integer from 2 to 4; x can be an integer from 1 to 6; L can be an acetylacetone ligand with the following structure.

[0242] (R 1 and R 3 Each independently is C1-C 10 Alkyl or C6-C 20 Aryl, the R 1 and R3 The alkyl and aryl groups can be further selected from halogens, C1-C... 10 Alkyl, C6-C 20 Aryl, halogenated C1-C 10 Alkyl and halogenated C6-C 20 One or more substituents in the aryl group are substituted;

[0243] R 2 Hydrogen, halogen, C1-C 10 Alkyl or C6-C 20 Aryl, the R 2 The alkyl and aryl groups can be further selected from halogens, C1-C... 10 Alkyl, C6-C 20 Aryl, halogenated C1-C 10 Alkyl and halogenated C6-C 20 One or more of the aryl groups are substituted;

[0244] The R 1 and R 2 , or R 3 and R 2 Through C3-C 10 Alkylene, C3-C 10 alkenyl, C6-C 20 Aromatic, C3-C 10 Heteroalkylene, C3-C 10 Heteroene or C6-C 20 (The heteroarylene groups connect to form a ring.)

[0245] According to one embodiment, the ethylene oligomerization catalyst comprises a chromium catalyst precursor, which is prepared into a homogeneous solution phase from a chromium(III) precursor and low-cost raw materials such as Lewis acids containing Group 13 elements, and a heteroatom ligand. In the absence of the use of aluminoxane co-catalysts such as methylaluminoxane (MAO), ethylene oligomerization is achieved in situ together with an organoboron compound-based co-catalyst, thereby stably maintaining the activity of the reaction and enabling the preparation of 1-hexene and 1-octene with high activity, high selectivity and high yield.

[0246] Specifically, the ethylene oligomerization catalyst can be prepared by mixing and reacting a chromium catalyst precursor with heteroatom ligands of various structures without separate separation and purification processes. The chromium catalyst precursor is the product of reacting a chromium(III) precursor and a Lewis acid containing a Group 13 element in an inert solvent at the same stoichiometric ratio and can exist in a homogeneous solution phase. The prepared ethylene oligomerization catalyst can also be directly mixed with an organoboron compound-based cocatalyst without separate separation and purification processes and applied in-situ to the ethylene oligomerization reaction.

[0247] According to one embodiment, the ethylene oligomerization catalyst exhibits excellent catalytic activity, achieving superior selectivity for 1-hexene and 1-octene, significantly inhibiting the formation of polymers such as polyethylene, and preventing pipe blockage or scaling during the ethylene oligomerization process, thus being very economical and efficient.

[0248] Furthermore, the present invention provides a method for preparing ethylene oligomers, comprising the step of contacting a catalyst system with ethylene monomers to prepare ethylene oligomers, wherein the catalyst system comprises the ethylene oligomerization catalyst and an organoboron compound-based cocatalyst.

[0249] The method for preparing ethylene oligomers according to one embodiment is characterized in that, in order to prepare 1-hexene or 1-octene from ethylene with high activity and high selectivity, high-priced alkylaluminoxanes such as methylaluminoxane (MAO) and modified methylaluminoxane (MMAO) that have been conventionally used as cocatalysts are not used.

[0250] According to one embodiment of the preparation method, in order to effectively oligomerize ethylene, the catalyst system may include the ethylene oligomerization catalyst and an organoboron compound-based cocatalyst.

[0251] The ethylene oligomerization catalyst may comprise a chromium catalyst precursor of Formula 1 and heteroatom ligands. Specifically, the ethylene oligomerization catalyst can be prepared by mixing and reacting a chromium catalyst precursor with heteroatom ligands of various structures without separate separation and purification processes. The chromium catalyst precursor is the product of reacting a chromium(III) precursor and a Lewis acid containing a Group 13 element in an inert solvent at the same stoichiometric ratio and can exist in a homogeneous solution phase. The prepared ethylene oligomerization catalyst can also be directly mixed with an organoboron compound-based cocatalyst without separate separation and purification processes and applied in-situ to the ethylene oligomerization reaction.

[0252] According to one embodiment of the preparation method, the catalyst system comprises an organoboron compound-based cocatalyst as a cocatalyst for activating the oligomerization catalyst.

[0253] According to one embodiment, the organoboron compound-based cocatalyst can be an organoboron compound represented by the following chemical formula 9.

[0254] [Chemical Formula 9]

[0255] [R 31 R 32 R 33 Y] + [B(C6R 34 p H 5-p )4] -

[0256] In the chemical formula 9,

[0257] Y is either C or NH;

[0258] R 31 To R 33 Each independently is hydrogen, C1-C 20 Alkyl or C6-C 20 Aryl, the R 31 The alkyl or aryl groups can be further selected from C1-C1. 20 Alkyl and C6-C 20 One or more of the aryl groups are substituted;

[0259] R 34 It is fluorine, C1-C 20 Alkyl or C1-C 20 Alkoxy, the R 34 The alkyl or alkoxy group can be further substituted with more than one fluorine molecule;

[0260] p is an integer from 3 to 5.

[0261] In one embodiment, Y in chemical formula 9 can be C.

[0262] Specific examples of the organoboron compounds include triphenylcarbium tetra(pentafluorophenyl)borate, triphenylcarbium tetra(trifluoromethylphenyl)borate, triphenylcarbium tetra(3,5-bis(trifluoromethyl)phenyl)borate, trimethylammonium tetra(trifluoromethylphenyl)borate, triethylammonium tetra(pentafluorophenyl)borate, tripropylammonium tetra(pentafluorophenyl)borate, tributylammonium tetra(trifluoromethylphenyl)borate, tributylammonium tetra(pentafluorophenyl)borate, tributylammonium tetra(3,5-bis(trifluoromethyl)phenyl)borate, and N,N-dimethylphenylammonium. Tetra(pentafluorophenyl)borate, N,N-diethylphenylammonium tetra(pentafluorophenyl)borate, N,N-dimethylphenylammonium tetra(3,5-bis(trifluoromethyl)phenyl)borate, methyldiphenylammonium tetra(pentafluorophenyl)borate, ethyldiphenylammonium tetra(pentafluorophenyl)borate, etc., can be used alone or in combination of two or more. Preferably, one or more of triphenylcarbium tetra(pentafluorophenyl)borate, triphenylcarbium tetra(trifluoromethylphenyl)borate and triphenylcarbium tetra(3,5-bis(trifluoromethyl)phenyl)borate can be used.

[0263] In one embodiment of the preparation method, in order to achieve high activity, the catalyst system may further comprise an alkylaluminum compound represented by the following chemical formula 10.

[0264] [Chemical Formula 10]

[0265] AlR 41 R 42 R43

[0266] In the chemical formula 10,

[0267] R 41 For C1-C 20 alkyl;

[0268] R 42 and R 43 Each independently is C1-C 20 Alkyl or halogen.

[0269] Preferably, in the chemical formula 10, R 41 R 42 and R 43 Each can be independently C1-C 10 Alkyl, more preferably, R 41 R 42 and R 43 Each can be an independent C1-C6 alkyl group.

[0270] Specific examples of the alkylaluminum include trimethylaluminum (TMA), triethylaluminum (TEAL), tripropylaluminum, triisobutylaluminum (TIBA), trihexylaluminum, tri-n-octylaluminum, methylaluminum chloride, ethylaluminum chloride, propylaluminum chloride, isobutylaluminum chloride, hexylaluminum chloride, dimethylaluminum chloride, diethylaluminum chloride, dipropylaluminum chloride, diisobutylaluminum chloride, dihexylaluminum chloride, etc. These can be used alone or in combination of two or more. Preferably, one or more of triethylaluminum (TEAL), triisobutylaluminum (TIBA), trihexylaluminum, and tri-n-octylaluminum can be used.

[0271] When the organoboron compound of Formula 9 and the alkylaluminum compound of Formula 10 are used in combination, the efficiency of the ethylene oligomerization reaction can be further increased.

[0272] In one embodiment of the method for preparing ethylene oligomers, the ratio of the ethylene oligomerizing catalyst to the organoboron compound-based cocatalyst, based on the molar ratio of chromium (Cr) atoms to boron (B) atoms, can be from 1:1 to 1000, preferably from 1:1 to 500, and more preferably from 1:1 to 100. Within this range, excellent ethylene oligomerizing activity can be maintained.

[0273] In one embodiment of the method for preparing ethylene oligomers, based on the molar ratio of chromium (Cr) atoms:boron (B) atoms:aluminum (Al) atoms, the ratio of the ethylene oligomerizing catalyst, the organoboron compound-based cocatalyst, and the alkylaluminum compound can be from 1:1 to 1000:100 to 10000, preferably from 1:1 to 500:100 to 5000, and more preferably from 1:1 to 100:500 to 5000. Within the above range, superior ethylene oligomerizing activity can be maintained.

[0274] In addition to the ethylene oligomerization catalyst and the organoboron compound-based co-catalyst, the catalyst system may contain other possible components as long as it does not impair the essence of the present invention.

[0275] According to one embodiment of the preparation method, the catalyst system can be prepared by adding an organoboron compound-based co-catalyst to an ethylene oligomerization catalyst existing in a homogeneous solution phase. In this case, the catalyst system may also contain an inert solvent. The inert solvent may be the same as the polymerization solvent described later. The mixing of the ethylene oligomerization catalyst and the organoboron compound-based co-catalyst can be carried out at a temperature of 20-250°C. The presence of olefins during the mixing of the catalyst components generally exhibits a protective effect, thus providing improved catalytic performance. A more preferred temperature range is 20-100°C.

[0276] According to one embodiment of the preparation method, the ethylene oligomer is an ethylene oligomer, particularly 1-hexene or 1-octene, which can be prepared by means of a homogeneous liquid-phase reaction, a two-phase liquid / liquid reaction, a bulk reaction in which the product olefin acts as the main medium, or a gas-phase reaction in the presence of an inert solvent, using the catalyst system according to the invention and conventional equipment and contact technology. However, a homogeneous liquid-phase reaction is preferred in the presence of an inert solvent.

[0277] According to one embodiment of the preparation method, the ethylene oligomerization reaction can be carried out in an inert solvent, i.e., in any inert solvent that does not react with the ethylene oligomerization catalyst and the organoboron compound-based cocatalyst of the present invention. In terms of improving catalyst solubility and catalytic activity, the inert solvent can be a hydrocarbon-based solvent, specifically an aliphatic or aromatic hydrocarbon solvent that is halogen-substituted or unsubstituted.

[0278] Specifically, the hydrocarbon solvent can be a C4-C4 solvent that is halogenated or unsubstituted. 20 Aliphatic hydrocarbon solvents, halogenated or unsubstituted C6-C 20Aromatic hydrocarbon solvents, mixtures thereof, etc. More specifically, examples include hexane, heptane, octane, nonene, decane, undecane, dodecane, tetradecane, dimethylpentane, trimethylpentane, methylhexane, dimethylhexane, methylheptane, dichloromethane, cyclohexane, methylcyclohexane (MCH), ethylcyclohexane, isopropylcyclohexane, dimethylcyclohexane, trimethylcyclohexane, benzene, toluene, xylene, mesitylene, ethylbenzene, isopropylbenzene, chlorobenzene (CB), dichlorobenzene, fluorobenzene, etc., preferably hexane, heptane, cyclohexane, methylcyclohexane (MCH), toluene, chlorobenzene (CB), or combinations thereof. When using the hydrocarbon solvents exemplified above, the separation of 1-hexene and 1-octene, as products of the oligomerization reaction, from the solvent is easier, and they can have high reactivity.

[0279] According to one embodiment of the preparation method, the ethylene oligomerization reaction can be carried out at a temperature of 20-250°C, preferably at a temperature of 20-160°C, more preferably at a temperature of 60-160°C, and in terms of reaction pressure, it can be carried out at a pressure of atmospheric pressure to 100 bar, preferably at a pressure of 10-70 bar.

[0280] In one embodiment of the preparation method, the ethylene oligomer can be 1-hexene, 1-octene, or a mixture thereof.

[0281] According to one embodiment of the preparation method, 90% or more, preferably 95% or more, and more preferably 99% or more of 1-octene can be obtained relative to the total weight of the C8 products formed from ethylene via the ethylene oligomerization reaction. In this case, the yield refers to the percentage by weight of the 1-octene formed relative to the total weight of the C8 products formed.

[0282] According to one embodiment of the preparation method, 50% by weight or more, preferably 70% by weight or more, and more preferably 90% by weight or more of 1-hexene can be obtained relative to the total weight of the C6 product formed from ethylene via the ethylene oligomerization reaction. In this case, the yield refers to the percentage by weight of the 1-hexene formed relative to the total weight of the C6 product formed.

[0283] According to one embodiment of the preparation method, the ethylene oligomerization reaction can be carried out using equipment comprising any type of reactor. Examples of such reactors include, but are not limited to, batch reactors, semi-batch reactors, and continuous reactors. The equipment may be combined to include a reactor, an olefin reactor within the reactor, an inlet for the oligomerization catalyst system, a pipeline for discharging the oligomerization reaction products from the reactor, and at least one separator for separating the oligomerization reaction products. In this case, the catalyst system may comprise the aforementioned ethylene oligomerization catalyst and organoboron compound-based cocatalyst, or it may comprise a chromium catalyst precursor, heteroatom ligands, and an organoboron compound-based cocatalyst.

[0284] According to the present invention, an ethylene oligomerization catalyst is prepared and activated by an organoboron compound-based cocatalyst, and ethylene oligomerization is carried out in situ. Therefore, without using high-valent alkylaluminoxanes such as methylaluminoxane (MAO) and modified methylaluminoxane (MMAO) conventionally used as cocatalysts, the activity and selectivity of the ethylene oligomerization reaction can be significantly improved to an excellent level, thereby enabling the preparation of 1-hexene and 1-octene in high yields. Furthermore, the formation of polymer byproducts such as polyethylene can be further suppressed.

[0285] The effects of the present invention are specifically illustrated in the following embodiments. However, the following embodiments are merely illustrative of the present invention and do not limit the scope of the present invention.

[0286] Preparation of ligands

[0287] [Preparation Example 1] Preparation of Ligand L1

[0288] The entire reaction was carried out under a nitrogen atmosphere. 10.0 g (23.5 mmol) of 2,2'-dibromo-4,4'-di-tert-butyl-1,1'-biphenyl and 130 mL of diethyl ether were added to a 250 mL round-bottom flask (RBF), and the mixture was stirred for 30 minutes in an acetone / dry ice bath. Then, 19 mL (47.1 mmol) of n-butyllithium (n-BuLi) was added dropwise over 20 minutes. The reaction mixture was stirred at room temperature for 2 hours, and then stored in a liquid nitrogen bath for 10 minutes before adding 22.6 g (164 mmol) of PCl3 dropwise using a dropping funnel. After removing the reaction vessel from the liquid nitrogen bath, the mixture was stirred at room temperature for 1 hour. The solvent of the reactants was dried under vacuum, and the reactants were transferred to a glove box. 30 mL of hexane was added, and the mixture was stirred for 30 minutes. The resulting bright yellow solid was filtered, dried under vacuum at room temperature for 4 hours, and then 30 mL of acetonitrile was added, followed by stirring for 6 hours. The resulting white solid was filtered and dried at room temperature for 15 hours. In a glove box, 19.5 g of the resulting white powder (3,7-di-tert-butyl-chloro-5H-benzo[b]phosphindole, yield 83%) was added to 250 mL of RBF, followed by 50 mL of hexane and stirring at room temperature for 30 minutes. Then, 17.8 g (301 mmol) of isopropylamine was added in a single batch. The reactants were stirred at room temperature for 15 hours. The resulting white solid compound was removed by filtration, and the filtrate was vacuum dried to obtain 20.0 g of white powder (3,7-di-tert-butyl-N-isopropyl-5H-benzo[b]phosphindol-5-amine, yield 93%). In a glove box, 0.81 g (2.3 mmol) of 3,7-di-tert-butyl-N-isopropyl-5H-benzo[b]phosphindol-5-amine, 2.30 g (22.6 mmol) of triethylamine, and 16 mL of hexane were added to 100 mL of RBF, and the mixture was then stored in a glove box freezer (-20°C) for 30 minutes. Add 0.57 g (2.3 mmol) of chloro-di-o-tolylphosphine and 14 mL of hexane to a 20 mL glass vial, and then store it in a glove box freezer (-20 °C) for 30 minutes.The solution in a cooled 20 mL glass vial was added in one go to a cooled 100 mL RBF solution and stirred for 15 hours. The solid formed in the reaction mixture was removed by filtration, and the filtrate was then dried under vacuum. 30 mL of hexane was added to the dried reaction mixture and stirred for 30 minutes. The mixture was then added to a neutral alumina column calcined at 150 °C, and passed through a 120 mL solution of hexane:diethyl ether = 4:1. The solution was then dried under vacuum to obtain 0.64 g of a white solid (ligand L1).

[0289] 1 H NMR (500MHz), d-benzene, 25℃: δ=8.27(br,2H),7.79(br,3H),7.65(d,3H),7 .33(d,3H),7.13(br,3H),3.09(m,1H),2.51(br,6H),1.32(br,9H),1.05(br,6H)

[0290] [Preparation Example 2] Preparation of Ligand L2

[0291] In a glove box, 0.81 g (2.3 mmol) of 3,7-di-tert-butyl-N-isopropyl-5H-benzo[b]phosphine-indole-5-amine, 2.30 g (22.6 mmol) of triethylamine, and 16 mL of hexane were added to 100 mL of RBF, and then stored in a glove box freezer (-20 °C) for 30 minutes. In a 20 mL glass vial, 0.50 g (2.3 mmol) of chloro-di-phenylphosphine and 14 mL of hexane were added, and then stored in a glove box freezer (-20 °C) for 30 minutes. The cooled solution from the 20 mL vial was then added to a cooled 100 mL RBF and stirred for 15 hours. The solids formed in the reaction mixture were removed by filtration, and the filtrate was then dried under vacuum. 30 mL of hexane was added to the dried reactants and stirred for 30 minutes. The mixture was then added to a neutral alumina column calcined at 150 °C. The solution was then passed through 120 mL of a hexane:diethyl ether = 4:1 solution and dried under vacuum to obtain 0.55 g of a white solid (ligand L2).

[0292] 1 H NMR (500MHz), d-benzene, 25℃: δ=8.07(br,4H),7.65(br,3H),7.55(br,1H),7.34(br,6H),7.21(br,2H),2.89(m,1H),1.28(br,9H),1.10(br,6H)

[0293] [Preparation Example 3] Preparation of Ligand L3

[0294] The entire reaction was carried out under a nitrogen atmosphere. In a glove box, 9.90 g (29.9 mmol) of 3,7-di-tert-butyl-N-cyclobutyl-5H-benzo[b]phosphindol-5-amine and 50 mL of hexane were added to 250 mL of RBF and stirred at room temperature for 30 minutes. Then, 2.12 g (29.9 mmol) of cyclobutylamine was added in one batch. The reaction mixture was stirred at room temperature for 15 hours. The resulting white solid compound was filtered off, and the filtrate was vacuum dried to obtain 10.0 g of a white powder (3,7-di-tert-butyl-N-cyclobutyl-5H-benzo[b]phosphindol-5-amine, yield 91%). In a glove box, 0.84 g (2.3 mmol) of 3,7-di-tert-butyl-N-cyclobutyl-5H-benzo[b]phosphine-indole-5-amine, 2.30 g (22.6 mmol) of triethylamine, and 16 mL of hexane were added to 100 mL of RBF, and then stored in a glove box freezer (-20 °C) for 30 minutes. In a 20 mL glass vial, 0.57 g (2.3 mmol) of di-o-tolylphosphine chloride and 14 mL of hexane were added, and then stored in a glove box freezer (-20 °C) for 30 minutes. The cooled solution from the 20 mL vial was then added all at once to a cooled 100 mL of RBF, and the mixture was stirred for 15 hours. The solids formed in the reaction mixture were removed by filtration, and the filtrate was then dried under vacuum. 30 mL of hexane was added to the dried reactants and stirred for 30 minutes. The mixture was then added to a neutral alumina column calcined at 150 °C. The solution was then passed through 120 mL of a hexane:diethyl ether = 4:1 solution and dried under vacuum to obtain 0.85 g of a white solid (ligand L3).

[0295] 1 H NMR (500MHz), d-benzene, 25℃: δ=7.84(br,4H),7.67(d,3H),7.34(d,3H),7. 13(br,4H),3.68(m,1H),2.41(br,8H),1.63(br,2H),1.30(br,9H),0.93(br,2H)

[0296] [Preparation Example 4] Preparation of Ligand L4

[0297] In a glove box, 0.81 g (2.3 mmol) of 3,7-di-tert-butyl-N-isopropyl-5H-benzo[b]phosphine-indole-5-amine, 2.30 g (22.6 mmol) of triethylamine, and 16 mL of hexane were added to 100 mL of RBF, and then stored in a glove box freezer (-20 °C) for 30 minutes. In a 20 mL glass vial, 1.42 g (2.3 mmol) of chlorobis(4-(tributylsilyl)phenyl)phosphine and 14 mL of hexane were added, and then stored in a glove box freezer (-20 °C) for 30 minutes. The solution from the cooled 20 mL glass vial was added all at once to a cooled 100 mL RBF and stirred for 15 hours. The solids formed in the reaction mixture were removed by filtration, and the filtrate was then dried under vacuum. 30 mL of hexane was added to the dried reactants and stirred for 30 minutes. The mixture was then added to a neutral alumina column calcined at 150 °C. The solution was then passed through 120 mL of a hexane:diethyl ether = 4:1 solution and dried under vacuum to obtain 1.07 g of a clear oil (ligand L4).

[0298] 1 H NMR (500MHz), d-benzene, 25℃: δ=8.07(br,4),7.64(br,4H),7.55(br,4H),7.41(br,2H),2.96(m,1H),1.38(br,24H),1.11(br,6H),0.90(br,30H)

[0299] [Preparation Example 5] Preparation of Ligand L5

[0300] The entire reaction was carried out under a nitrogen atmosphere. 8.83 g (23.5 mmol) of 1-bromo-2-(2-bromophenyl)naphthalene and 130 mL of diethyl ether were added to 250 mL of RBF, and the mixture was stirred for 30 minutes in an acetone / dry ice bath. Then, 19 mL (47.1 mmol) of n-butyllithium was added dropwise over 20 minutes. The reaction mixture was stirred at room temperature for 2 hours, then stored in a liquid nitrogen bath for 10 minutes before adding 22.6 g (164 mmol) of PCl3 dropwise using a dropping funnel. After removing the reaction vessel from the liquid nitrogen bath, the mixture was stirred at room temperature for 1 hour. The solvent of the reaction mixture was dried under vacuum, and the mixture was transferred to a glove box. Then, 30 mL of hexane was added and the mixture was stirred for 30 minutes. The resulting bright yellow solid was filtered, dried under vacuum at room temperature for 4 hours, then 30 mL of acetonitrile was added and the mixture was stirred for 6 hours. The resulting white solid was filtered and dried at room temperature for 15 hours. In a glove box, 5.47 g of the formed white powder (11-chloro-11H-dibenzo[b,g]phosphindole, yield 82%) was added to 250 mL of RBF, followed by the addition of 50 mL of hexane and stirring at room temperature for 30 minutes. Then, 11.4 g (193 mmol) of isopropylamine was added in a single batch. The reaction mixture was stirred at room temperature for 15 hours, and the resulting white solid compound was filtered off. The filtrate was then vacuum dried to obtain 3.83 g of white powder (N-isopropyl-11H-dibenzo[b,g]phosphindol-11-amine, yield 65%). In a glove box, 0.70 g (2.3 mmol) of N-isopropyl-11H-dibenzo[b,g]phosphine indole-11-amine, 2.30 g (22.6 mmol) of triethylamine, and 16 mL of hexane were added to 100 mL of RBF, and then stored in a glove box freezer (-20 °C) for 30 minutes. In a 20 mL glass vial, 0.57 g (2.3 mmol) of di-o-tolylphosphine chloride and 14 mL of hexane were added, and then stored in a glove box freezer (-20 °C) for 30 minutes. The solution from the cooled 20 mL glass vial was added all at once to the cooled 100 mL of RBF, and the mixture was stirred for 15 hours. The solids formed in the reaction mixture were removed by filtration, and the filtrate was then dried under vacuum. 30 mL of hexane was added to the dried reactants and stirred for 30 minutes. The mixture was then added to a neutral alumina column calcined at 150 °C. The solution was then passed through 120 mL of a hexane:diethyl ether = 4:1 solution and dried under vacuum to obtain 0.34 g of a white solid (ligand L5).

[0301] 1 H NMR (500MHz), d-benzene, 25℃: δ = 7.61 (m, 10H), 7.05 (m, 8H), 3.18 (m, 1H), 2.50 (s, 6H), 0.98 (d, 6H)

[0302] [Preparation Example 6] Preparation of Ligand L6

[0303] The entire reaction was carried out under a nitrogen atmosphere. Except that 2,2'-dibromo-1,1'-biphenyl was used instead of 2,2'-dibromo-4,4'-di-tert-butyl-1,1'-biphenyl, the reaction was carried out under the same reaction conditions as in Preparation Example 1 (ligand L1) to obtain a white solid (ligand L6).

[0304] 1 H NMR (500MHz), d-benzene, 25℃: δ=7.82(br,6H),7.43(br,10H),2.61(m,1H),1.68(br,6H),1.25(br,6H)

[0305] [Preparation Example 7] Preparation of Ligand L7

[0306] The entire reaction was carried out under a nitrogen atmosphere. Except that 2,2'-dibromo-1,1'-biphenyl was used instead of 2,2'-dibromo-4,4'-di-tert-butyl-1,1'-biphenyl, and 1-butanamine was used instead of isopropylamine, the reaction was carried out under the same reaction conditions as in Preparation Example 1 (ligand L1) to obtain a white solid (ligand L7).

[0307] 1 H NMR (500MHz), d-benzene, 25℃: δ=7.83(d,6H),7.05~7.53(m,10H),2.47(b,2H),1.62(br,4H),1.25(br,6H),0.94(m,3H)

[0308] [Preparation Example 8] Preparation of Ligand L8

[0309] The entire reaction was carried out under a nitrogen atmosphere. Except that 5-chloro-5H-benzo[b]phosphineindole was used instead of 3,7-di-tert-butyl-N-isopropyl-5H-benzo[b]phosphineindole-5-amine, the reaction was carried out under the same reaction conditions as in Preparation Example 4 (ligand L4) to obtain a clear oil (ligand L8).

[0310] 1H NMR (500MHz), d-benzene, 25℃: δ=8.17(br,4),7.64~7.80(br,10H),7.35(br,4H),2.92(m,1H),1.38(br,24H),1.11(br,6H),0.89(br,30H)

[0311] The structures of the prepared ligands L1 to L8 are described in Table 1 below.

[0312] [Table 1]

[0313] Preparation of catalyst system and ethylene oligomerization reaction

[0314] [Example 1]

[0315] Preparation of precursor P1 and catalyst system (L1-P1+TTB)

[0316] The entire catalyst preparation process was carried out in a glove box. 40.0 mg (0.114 mmol) of Cr(acac)3, 16.7 mg (0.114 mmol) of B(OEt)3, 8 g of toluene, and 16.4 mg (0.228 mmol) of THF were added to 50 mL of RBF, and the mixture was stirred at room temperature for 15 hours. Ligand L1 (0.228 mmol) was added to the reaction mixture, and the mixture was stirred at room temperature for 15 hours. The resulting purple solid was filtered and vacuum dried for 12 hours, then mixed with 2 equivalents of trimethylbenzene tetrakis(pentafluorophenyl)borate (TTB) as a co-catalyst to prepare the catalyst system (L1-P1+TTB).

[0317] oligomerization

[0318] 765 g of methylcyclohexane was added to a 2 L high-pressure reactor, and the internal temperature of the reactor was raised to 35 °C and stirred. 1200 μmol of triethylaluminium (TEAL) was diluted in 6 g of methylcyclohexane and added to the reactor, followed by 1000 mL (cc) of hydrogen gas. While stirring, 110,000 mL of ethylene was added to the reactor at an internal temperature of 60 °C. The prepared catalyst system (L1-P1+TTB) was added to the reactor, and the oligomerization reaction was carried out for 80 minutes. The reaction mixture was cooled, 100 mL of ethanol was added, and the mixture was stirred for 30 minutes. The reaction solution was then filtered under reduced pressure through a paper filter to remove the formed polymer, dried, and weighed. A small amount of the filtrate was subjected to GC analysis to confirm the distribution of the oligomer products. The results are shown in Table 2 below.

[0319] [Example 2]

[0320] Preparation of precursor P2 and catalyst system (L1-P2+TTB)

[0321] The entire catalyst preparation process was carried out in a glove box. 40.0 mg (0.114 mmol) of Cr(acac)3, 13.0 mg (0.114 mmol) of AlCl3, 8 g of toluene, and 16.4 mg (0.228 mmol) of THF were added to 100 mL of RBF, and the mixture was stirred at room temperature for 15 hours. Ligand L1 (0.228 mmol) was then added to the reaction mixture, and the mixture was stirred at room temperature for 15 hours. The resulting green solid was filtered and vacuum dried for 12 hours, then mixed with 2 equivalents of TTB as a co-catalyst to prepare the catalyst system (L1-P2+TTB).

[0322] oligomerization

[0323] The prepared catalyst system (L1-P2+TTB) was used to carry out an oligomerization reaction in the same manner as in Example 1, and the results are recorded in Table 2 below.

[0324] [Example 3]

[0325] Preparation of precursor P3 and catalyst system (L1+P3+TTB)

[0326] The entire catalyst preparation process was carried out in a glove box. 40.0 mg (0.114 mmol) of Cr(acac)3, 16.7 mg (0.114 mmol) of B(OEt)3, and 8 g of chlorobenzene were added to 100 mL of RBF and stirred at room temperature for 15 hours. 1.0 μmol of the formed green reactant, 2.0 μmol of TTB as a co-catalyst, and 1.0 μmol of ligand L1 were diluted with 4.0 g of chlorobenzene to prepare the catalyst system (L1+P3+TTB) without further purification.

[0327] oligomerization

[0328] The prepared catalyst system (L1+P3+TTB) was used to carry out an oligomerization reaction in the same manner as in Example 1, and the results are recorded in Table 2 below.

[0329] [Example 4]

[0330] Preparation of precursor P1 and catalyst system (L2-P1+TTB)

[0331] The entire catalyst preparation process was carried out in a glove box. 40.0 mg (0.114 mmol) of Cr(acac)3, 16.7 mg (0.114 mmol) of B(OEt)3, 8 g of toluene, and 16.4 mg (0.228 mmol) of THF were added to 50 mL of RBF, and the mixture was stirred at room temperature for 15 hours. Ligand L2 (0.228 mmol) was then added to the reaction mixture, and the mixture was stirred at room temperature for 15 hours. The resulting purple solid was filtered and vacuum dried for 12 hours, then mixed with 2 equivalents of TTB as a co-catalyst to prepare the catalyst system (L2-P1+TTB).

[0332] oligomerization

[0333] The prepared catalyst system (L2-P1+TTB) was used to carry out an oligomerization reaction in the same manner as in Example 1, and the results are recorded in Table 2 below.

[0334] [Example 5]

[0335] Preparation of precursor P1 and catalyst system (L3-P1+TTB)

[0336] The entire catalyst preparation process was carried out in a glove box. 40.0 mg (0.114 mmol) of Cr(acac)3, 16.7 mg (0.114 mmol) of B(OEt)3, 8 g of toluene, and 16.4 mg (0.228 mmol) of THF were added to 50 mL of RBF, and the mixture was stirred at room temperature for 15 hours. Ligand L3 (0.228 mmol) was then added to the reaction mixture, and the mixture was stirred at room temperature for 15 hours. The resulting purple solid was filtered and vacuum dried for 12 hours, then mixed with 2 equivalents of TTB as a co-catalyst to prepare the catalyst system (L3-P1+TTB).

[0337] oligomerization

[0338] The prepared catalyst system (L3-P1+TTB) was used to carry out an oligomerization reaction in the same manner as in Example 1, and the results are recorded in Table 2 below.

[0339] [Example 6]

[0340] Preparation of precursor P1 and catalyst system (L4-P1+TTB)

[0341] The entire catalyst preparation process was carried out in a glove box. 40.0 mg (0.114 mmol) of Cr(acac)3, 16.7 mg (0.114 mmol) of B(OEt)3, 8 g of toluene, and 16.4 mg (0.228 mmol) of THF were added to 50 mL of RBF, and the mixture was stirred at room temperature for 15 hours. Ligand L4 (0.228 mmol) was then added to the reaction mixture, and the mixture was stirred at room temperature for 15 hours. The resulting purple solid was filtered and vacuum dried for 12 hours, then mixed with 2 equivalents of TTB as a co-catalyst to prepare the catalyst system (L4-P1+TTB).

[0342] oligomerization

[0343] The prepared catalyst system (L4-P1+TTB) was used to carry out an oligomerization reaction in the same manner as in Example 1, and the results are recorded in Table 2 below.

[0344] [Example 7]

[0345] Preparation of precursor P1 and catalyst system (L5-P1+TTB)

[0346] The entire catalyst preparation process was carried out in a glove box. 40.0 mg (0.114 mmol) of Cr(acac)3, 16.7 mg (0.114 mmol) of B(OEt)3, 8 g of toluene, and 16.4 mg (0.228 mmol) of THF were added to 50 mL of RBF, and the mixture was stirred at room temperature for 15 hours. Ligand L5 (0.228 mmol) was then added to the reaction mixture, and the mixture was stirred at room temperature for 15 hours. The resulting purple solid was filtered and vacuum dried for 12 hours, then mixed with 2 equivalents of TTB as a co-catalyst to prepare the catalyst system (L5-P1+TTB).

[0347] oligomerization

[0348] The prepared catalyst system (L5-P1+TTB) was used to carry out an oligomerization reaction in the same manner as in Example 1, and the results are recorded in Table 2 below.

[0349] [Comparative Example 1] Oligopolymerization reaction using MAO co-catalyst

[0350] Preparation of Cr-L1 catalyst

[0351] At 40 °C, 331 mg (0.88 mmol) of CrCl3(THF)3 and 500 mg (0.88 mmol) of ligand L1 were stirred for 6 hours in 10 mL of acetonitrile. The resulting bluish-green solid was filtered and washed with 5 mL of acetonitrile. The remaining solid was then dried under vacuum at room temperature for 15 hours to obtain catalyst Cr-L1 (yield 87%).

[0352] oligomerization

[0353] 765 g of methylcyclohexane was added to a 2 L high-pressure reactor, and the internal temperature of the reactor was raised to 35 °C while stirring. 1200 μmol of TEAL was diluted in 6 g of methylcyclohexane and added to the reactor, followed by 1000 mL of hydrogen gas. While stirring, 110,000 mL of ethylene was added to the reactor at an internal temperature of 60 °C. 600 μmol of MAO was diluted in 6 g of methylcyclohexane and added to the reactor, followed by 1 μmol of the prepared catalyst Cr-L1 diluted in 4.0 g of chlorobenzene and added to the reactor. The oligomerization reaction was then carried out for 80 minutes. After cooling the reaction mixture, 100 mL of ethanol was added and the mixture was stirred for 30 minutes. The reaction solution was then filtered under reduced pressure through a paper filter to remove the formed polymer, dried, and weighed. A small amount of the filtrate was subjected to GC analysis to confirm the distribution of the oligomer products. The results are shown in Table 2 below.

[0354] [Table 2] Oligopolymerization Results

[0355] The oligomerization results in Table 2 confirm that, compared to Comparative Example 1 which used a methylaluminoxane (MAO) cocatalyst, the catalyst systems using a Cr complex (LP) formed by the reaction between a catalyst precursor and a phosphine ligand as a catalyst and mixed with an organoboron compound-based cocatalyst (L-P+TTB, Examples 1, 2, 4 to 7) and the catalyst system using a mixture of a catalyst precursor and a phosphine ligand and prepared in situ (L+P) and mixed with an organoboron compound-based cocatalyst (L+P+TTB, Example 3) exhibited high 1-octene preparation activity or low polymer formation amounts.

[0356] In particular, it can be confirmed that less polymer is formed in the case of a catalyst system (L-P+TTB) in which Cr complex (LP) is used as a catalyst and mixed with an organoboron compound-based co-catalyst, compared with the catalyst system (L+P+TTB) in which an in-situ catalyst (L+P) and an organoboron compound-based co-catalyst are mixed.

[0357] Furthermore, depending on the type of phosphine ligand, the activity of 1-octene preparation and the amount of polymer formed varied. In particular, when substituents other than hydrogen were introduced onto the benzene ring of the dibenzophosphole moiety of the phosphine ligand (Examples 1, 4, 6, and 7), a high amount of 1-octene and a low amount of polymer formed were confirmed.

[0358] As described above, embodiments of the present invention have been described in detail. However, those skilled in the art can make various modifications to the invention without departing from the spirit and scope of the invention as defined in the claims. Therefore, changes to subsequent embodiments of the invention will not depart from the technology of the invention.

Claims

1. A chromium catalyst precursor, represented by the following chemical formula 1: [Chemical Formula 1] In the chemical formula 1, M 1 It is either boron (B) or aluminum (Al); L is a ligand in the form of a β-ketoenol salt; R is a halogen, C1-C 10 Alkyl or C6-C 20 aryloxy; W is a nitrile having 2 to 30 carbon atoms or a cyclic or acyclic ether having 2 to 30 carbon atoms; n is an integer of 1 or 2; x is an integer from 1 to 6; m is an integer from 2 to 4.

2. The chromium catalyst precursor according to claim 1, wherein, The L is an enol ligand represented by the following chemical formula A: [Chemical Formula A] In the chemical formula A, R 1 and R 3 Each can be independently a halogen, a hydrocarbon group, a substituted hydrocarbon group, a heterohydrocarbon group, or a substituted heterohydrocarbon group; R 2 It can be hydrogen, halogen, hydrocarbon group, substituted hydrocarbon group, heterohydrocarbon group or substituted heterohydrocarbon group; The R 1 and R 2 , or R 3 and R 2 A ring can be formed by linking alkylene groups, substituted alkylene groups, heteroalkylene groups, or substituted heteroalkylene groups.

3. The chromium catalyst precursor according to claim 1, wherein, The W is acetonitrile (ACN), tetrahydrofuran (THF), or diethyl ether.

4. The chromium catalyst precursor according to claim 1, wherein, R is a halogen or C1-C. 10 Alkyl group; W is acetonitrile (ACN), tetrahydrofuran (THF), or diethyl ether; m is an integer from 2 to 4; x is an integer from 1 to 6; L is an acetylacetone ligand with the following structure. R 1 and R 3 Each independently is C1-C 10 Alkyl or C6-C 20 Aryl, the R 1 and R 3 The alkyl and aryl groups can be further selected from halogens, C1-C... 10 Alkyl, C6-C 20 Aryl, halogenated C1-C 10 Alkyl and halogenated C6-C 20 One or more substituents are substituted in the aryl group; R 2 Hydrogen, halogen, C1-C 10 Alkyl or C6-C 20 Aryl, the R 2 The alkyl and aryl groups can be further selected from halogens, C1-C... 10 Alkyl, C6-C 20 Aryl, halogenated C1-C 10 Alkyl and halogenated C6-C 20 One or more of the aryl groups are substituted; The R 1 and R 2 , or R 3 and R 2 Through C3-C 10 Alkylene, C3-C 10 alkenyl, C6-C 20 aryl, C3-C 10 Heteroalkylene, C3-C 10 Heteroene or C6-C 20 The heteroaryl groups are linked to form a ring.

5. The chromium catalyst precursor according to claim 4, wherein, The M 1 Boron (B); L is acetylacetonate; R is Cl-C 10 Alkoxy; W is acetonitrile (ACN), tetrahydrofuran (THF), or diethyl ether; m is an integer from 2 to 4; x is an integer from 1 to 6.

6. The chromium catalyst precursor according to claim 4, wherein, The M 1 L is aluminum (Al); R is acetylacetonate; W is acetonitrile (ACN), tetrahydrofuran (THF), or diethyl ether; m is an integer from 2 to 4; x is an integer from 1 to 6.

7. An ethylene oligomerization catalyst comprising a chromium catalyst precursor represented by Chemical Formula 1 and a heteroatom ligand represented by Chemical Formula 3: [Chemical Formula 1] In the chemical formula 1, M 1 It is either boron (B) or aluminum (Al); L is a ligand in the form of a β-ketoenol salt; R is a halogen, C1-C 10 Alkyl or C6-C 20 aryloxy; W is a neutral coordinating ligand; x is an integer from 1 to 6; m is an integer from 0 to 4. [Chemical Formula 3] In the chemical formula 3 R 11 and R 12 Each can be independently a hydrocarbon group, a heterohydrocarbon group, a substituted hydrocarbon group, or a substituted heterohydrocarbon group; Y is the linking group between P and Z; Z is or ; Ring A and ring B are each an aromatic ring independently; L 1 and L 2 Each can be independently a single bond, a heteroatom, a substituted heteroatom, -C(=O)- or -CR'R''-; R' and R'' can each independently be hydrogen, hydrocarbon group, substituted hydrocarbon group, heterohydrocarbon group or substituted heterohydrocarbon group; R 13 To R 16 Each can be independently a hydrocarbon group, a heterohydrocarbon group, a substituted hydrocarbon group, or a substituted heterohydrocarbon group; c and d are each independent integers from 0 to 4.

8. The ethylene oligomerization catalyst according to claim 7, wherein, The Y is a hydrocarbon group, -N(R) 21 )-、-N(R 21 )-N(R 22 )-、=C(R 23 )-N(R 21 )-、-N(R 21 )-C(R 23 (R) 24 - or -N(R) 21 )-L 3 -N(R 22 )-; R 21 To R 24 Independently, it can be hydrogen, a hydrocarbon group, a substituted hydrocarbon group, a heterohydrocarbon group, a substituted heterohydrocarbon group, or a substituted heteroatom; L 3 It is a hydrocarbon group.

9. The ethylene oligomerization catalyst according to claim 7, wherein, The heteroatom ligand is represented by the following chemical formula 4 or chemical formula 5: [Chemical Formula 4] [Chemical Formula 5] In chemical formulas 4 and 5, Rings A and B are each independently C6-C 20 Aromatic rings; R 11 To R 14 R 15 and R 16 Each independently is C6-C 20 Aryl, C6-C 20 Aryl C1-C 10 Alkyl, C6-C 20 Aryl C2-C 10 alkenyl, C6-C 20 Aryl C2-C 10 alkynyl group, C1-C 10 Alkyl, C2-C 10 alkenyl, C2-C 10 Alkyne group, C1-C 10 Alkoxy, C6-C 20 aryloxy group, C1-C 10 alkoxycarbonyl, C1-C 10 Alkyl carbonyl group, C2-C 10 alkenyl carbonyl group, C2-C 10 alkynyl carbonyl group, amino carbonyl group, C1-C 10 Alkyl carbonyl amino, C2-C 10 alkenyl carbonyl amino, C2-C 10 alkynyl carbonyl amino, C3-C 10 Cycloalkyl, mercapto C1-C 10 Alkyl, mercapto C2-C 10 alkenyl, mercapto C2-C 10 alkynyl group, C3-C 20 Heteroaryl, 5- to 7-membered heterocyclic alkyl, -NR a1 R b1 or -SiR c1 R d1 R e1 ; R a1 and R b1 Each independently is hydrogen, C1-C 10 Alkyl, C2-C 10 alkenyl, C2-C 10 alkynyl group, C6-C 20 Aryl, C1-C 10 Alkylamino, C2-C 10 alkenyl amino or C2-C 10 alkynylamino; R c1 For C1-C 10 Alkyl, C2-C 10 alkenyl, C2-C 10 alkynyl or C6-C 20 Aryl; R d1 and R e1 Each independently is hydrogen, C1-C 10 Alkyl, C2-C 10 alkenyl, C2-C 10 alkynyl or C6-C 20 Aryl; R 21 For C1-C 10 Alkyl, C2-C 10 alkenyl, C2-C 10 alkynyl group, C6-C 20 Aryl, C6-C 20 Aryl C1-C 10 Alkyl, C6-C 20 Aryl C2-C 10 alkenyl, C6-C 20 Aryl C2-C 10 alkynyl group, C3-C 10 cycloalkyl, C3-C 20 Heteroaryl, 5- to 7-membered heterocyclic alkyl, C1-C 10 Alkoxy, C6-C 20 aryloxy group, C1-C 10 alkoxycarbonyl, C1-C 10 Alkyl carbonyl group, C2-C 10 alkenyl carbonyl group, C2-C 10 alkynyl carbonyl group, amino carbonyl group, C1-C 10 Alkyl carbonyl amino, C2-C 10 alkenyl carbonyl amino, C2-C 10 alkynyl carbonyl amino, -NR a2 R b2 or -SiR c2 R d2 R e2 ; L 1 and L 2 Each can be a single bond, -O-, -S-, -NR'-, -P(=O)R'-, -P(=Se)R'-, -P(=S)R'-, -SiR'R''-, -CR'R''-, or -C(=O)-; R' and R'' are each independently hydrogen, C1-C 10 Alkyl, C2-C 10 alkenyl, C2-C 10 alkynyl group, C6-C 20 Aryl, C6-C 20 Aryl C1-C 10 Alkyl, C6-C 20 Aryl C2-C 10 alkenyl, C6-C 20 Aryl C2-C 10 alkynyl group, C3-C 10 cycloalkyl, C3-C 20 Heteroaryl, 5- to 7-membered heterocyclic alkyl, C1-C 10 Alkoxy, C6-C 20 aryloxy group, C1-C 10 alkoxycarbonyl, C1-C 10 Alkyl carbonyl group, C2-C 10 alkenyl carbonyl group, C2-C 10 alkynyl carbonyl group, amino carbonyl group, C1-C 10 Alkyl carbonyl amino, C2-C 10 alkenyl carbonyl amino, C2-C 10 alkynyl carbonyl amino, -NR a3 R b3 or -SiR c3 R d3 R e3 ; R a2 R b2 R a3 and R b3 Each independently is hydrogen, C1-C 10 Alkyl, C2-C 10 alkenyl, C2-C 10 alkynyl or C6-C 20 Aryl; R c2 and R c3 Each independently is C1-C 10 Alkyl, C2-C 10 alkenyl, C2-C 10 alkynyl or C6-C 20 Aryl; R d2 R e2 R d3 and R e3 Each independently is hydrogen, C1-C 10 Alkyl, C2-C 10 alkenyl, C2-C 10 alkynyl or C6-C 20 Aryl; c and d are each independent integers from 0 to 4; The R 11 To R 14 R 15 and R 16 aryl, arylalkyl, alkyl, arylalenyl, alkenyl, arylynyl, alkoxy, aryloxy, cycloalkyl, heteroaryl or heterocycloalkyl and R 21 The alkyl, alkenyl, aryl, arylalkyl, arylalkenyl, arylynyl, cycloalkyl, heteroaryl, heterocycloalkyl, alkoxy, aryloxy, alkoxycarbonyl, alkylcarbonyloxy, alkenylcarbonyloxy, alkynylcarbonyloxy, aminocarbonyl, alkylcarbonylamino, alkenylcarbonylamino, or alkynylcarbonylamino groups of R' and R'' may be further selected from halogens, C1-C 10 Alkyl, halogenated C1-C 10 Alkyl, C2-C 10 alkenyl, C2-C 10 Alkyne group, C1-C 10 Alkoxy, halogenated C1-C 10 Alkoxy, C6-C 20 Aryl, C6-C 20 Aryloxy, 5- to 7-membered heterocyclic alkyl, -NR a4 R b4 and -SiR c4 R d4 R e4 One or more substitutions in; R a4 and R b4 Each independently is hydrogen, C1-C 10 Alkyl, C2-C 10 alkenyl, C2-C 10 alkynyl or C6-C 20 Aryl, R c4 To R e4 Each independently is C1-C 10 Alkyl or C1-C 10 Alkyl group.

10. The ethylene oligomerization catalyst according to claim 9, wherein, The L 1 and L 2 Each can be a single bond or -O- independently.

11. The ethylene oligomerization catalyst according to claim 10, wherein, The heteroatom ligand is represented by the following chemical formula 6: [Chemical Formula 6] In the chemical formula 6, R 11 and R 12 Each independently is C6-C 20 Aryl, C6-C 20 Aryl C1-C 10 Alkyl, C6-C 20 Aryl C2-C 10 alkenyl, C6-C 20 Aryl C2-C 10 Alkyne group, C1-C 10 Alkyl, C2-C 10 alkenyl, C2-C 10 Alkyne group, C1-C 10 Alkoxy, C6-C 20 aryloxy group, C1-C 10 alkoxycarbonyl, C1-C 10 Alkyl carbonyl group, C2-C 10 alkenyl carbonyl group, C2-C 10 alkynyl carbonyl group, amino carbonyl group, C1-C 10 Alkyl carbonyl amino, C2-C 10 alkenyl carbonyl amino, C2-C 10 alkynyl carbonyl amino, C3-C 10 Cycloalkyl, mercapto C1-C 10 Alkyl, mercapto C2-C 10 alkenyl, mercapto C2-C 10 alkynyl group, C3-C 20 Heteroaryl, 5- to 7-membered heterocyclic alkyl, -NR a1 R b1 or -SiR c1 R d1 R e1 ; R a1 and R b1 Each independently is hydrogen, C1-C 10 Alkyl, C2-C 10 alkenyl, C2-C 10 alkynyl group, C6-C 20 Aryl, C1-C 10 Alkylamino, C2-C 10 alkenyl amino or C2-C 10 alkynylamino; R c1 For C1-C 10 Alkyl, C2-C 10 alkenyl, C2-C 10 alkynyl or C6-C 20 Aryl; R d1 and R e1 Each independently is hydrogen, C1-C 10 Alkyl, C2-C 10 alkenyl, C2-C 10 alkynyl or C6-C 20 Aryl; R 21 For C1-C 10 Alkyl, C2-C 10 alkenyl, C2-C 10 alkynyl group, C6-C 20 Aryl, C6-C 20 Aryl C1-C 10 Alkyl, C6-C 20 Aryl C2-C 10 alkenyl, C6-C 20 Aryl C2-C 10 alkynyl group, C3-C 10 cycloalkyl, C3-C 20 Heteroaryl, 5- to 7-membered heterocyclic alkyl, C1-C 10 Alkoxy, C6-C 20 aryloxy group, C1-C 10 alkoxycarbonyl, C1-C 10 Alkyl carbonyl group, C2-C 10 alkenyl carbonyl group, C2-C 10 alkynyl carbonyl group, amino carbonyl group, C1-C 10 Alkyl carbonyl amino, C2-C 10 alkenyl carbonyl amino, C2-C 10 alkynyl carbonyl amino, -NR a2 R b2 or -SiR c2 R d2 R e2 ; R a2 and R b2 Each independently is hydrogen, C1-C 10 Alkyl, C2-C 10 alkenyl, C2-C 10 alkynyl or C6-C 20 Aryl; R c2 For C1-C 10 Alkyl, C2-C 10 alkenyl, C2-C 10 alkynyl or C6-C 20 Aryl; R d2 and R e2 Each independently is hydrogen, C1-C 10 Alkyl, C2-C 10 alkenyl, C2-C 10 alkynyl or C6-C 20 Aryl; The C ring and D ring are each independently benzene or naphthalene; R 22 and R 23 Hydrogen, C1-C 10 Alkyl, C6-C 20 Aryl, C3-C 10 cycloalkyl, C6-C 20 Aryl C1-C 10 Alkyl or C1-C 10 Alkyl C6-C 20 Aryl; The R 11 and R 12 aryl, arylalkyl, alkyl, arylalenyl, alkenyl, arylynyl, alkoxy, aryloxy, cycloalkyl, heteroaryl, heterocycloalkyl and R 21 The alkyl, alkenyl, aryl, arylalkyl, arylalkenyl, arylynyl, cycloalkyl, heteroaryl, heterocycloalkyl, alkoxy, aryloxy, alkoxycarbonyl, alkylcarbonyloxy, alkenylcarbonyloxy, alkynylcarbonyloxy, aminocarbonyl, alkylcarbonylamino, alkenylcarbonylamino, or alkynylcarbonylamino can be further selected from halogens, C1-C 10 Alkyl, halogenated C1-C 10 Alkyl, C2-C 10 alkenyl, C2-C 10 Alkyne group, C1-C 10 Alkoxy, halogenated C1-C 10 Alkoxy, C6-C 20 Aryl, C6-C 20 Aryloxy, 5- to 7-membered heterocyclic alkyl, -NR a4 R b4 and -SiR c4 R d4 R e4 One or more substitutions in; R a4 and R b4 Each independently is hydrogen, C1-C 10 Alkyl, C2-C 10 alkenyl, C2-C 10 alkynyl or C6-C 20 Aryl, R c4 To R e4 Each independently is C1-C 10 Alkyl or C1-C 10 Alkyl group.

12. The ethylene oligomerization catalyst according to claim 7, wherein, R is a halogen or C1-C. 10 Alkyl group; W is acetonitrile (ACN), tetrahydrofuran (THF), diethyl ether, or water (H2O); m is an integer from 2 to 4; x is an integer from 1 to 6; L is an acetylacetone ligand with the following structure. R 1 and R 3 Each independently is C1-C 10 Alkyl or C6-C 20 Aryl, the R 1 and R 3 The alkyl and aryl groups can be further selected from halogens, C1-C... 10 Alkyl, C6-C 20 Aryl, halogenated C1-C 10 Alkyl and halogenated C6-C 20 One or more substituents are substituted in the aryl group; R 2 Hydrogen, halogen, C1-C 10 Alkyl or C6-C 20 Aryl, the R 2 The alkyl and aryl groups can be further selected from halogens, C1-C... 10 Alkyl, C6-C 20 Aryl, halogenated C1-C 10 Alkyl and halogenated C6-C 20 One or more of the aryl groups are substituted; The R 1 and R 2 , or R 3 and R 2 Through C3-C 10 Alkylene, C3-C 10 alkenyl, C6-C 20 aryl, C3-C 10 Heteroalkylene, C3-C 10 Heteroene or C6-C 20 The heteroaryl groups are linked to form a ring.

13. A method for preparing ethylene oligomers, comprising the step of contacting a catalyst system with ethylene monomers to prepare ethylene oligomers, wherein, The catalyst system comprises the ethylene oligomerization catalyst according to any one of claims 7 to 12 and an organoboron compound-based co-catalyst.

14. The method for preparing ethylene oligomers according to claim 13, wherein, The organoboron compound-based cocatalyst is an organoboron compound represented by the following chemical formula 9: [Chemical Formula 9] [R 31 R 32 R 33 Y] + [B(C6R 34 p H 5-p )4] - In the chemical formula 9, Y is either C or NH; R 31 To R 33 Each independently is hydrogen, C1-C 20 Alkyl or C6-C 20 Aryl, the R 31 The alkyl or aryl groups can be further selected from C1-C1. 20 Alkyl and C6-C 20 One or more of the aryl groups are substituted; R 34 It is fluorine, C1-C 20 Alkyl or C1-C 20 Alkoxy, the R 34 The alkyl or alkoxy group can be further substituted with more than one fluorine molecule; p is an integer from 3 to 5.

15. The method for preparing ethylene oligomers according to claim 14, wherein, The catalyst system also includes an alkylaluminum compound represented by the following chemical formula 10: [Chemical Formula 10] AlR 41 R 42 R 43 In the chemical formula 10, R 41 For C1-C 20 alkyl; R 42 and R 43 Each independently is C1-C 20 Alkyl or halogen.

16. The method for preparing ethylene oligomers according to claim 13, wherein, The ethylene oligomer is 1-hexene, 1-octene, or a mixture thereof.

17. The method for preparing ethylene oligomers according to claim 13, wherein, Hydrocarbon-based solvents are used as reaction solvents.

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