Catalyst for olefin polymerization, preparation method thereof and olefin polymerization method

Abstract

The invention relates to the technical field of olefin polymerization, and discloses a catalyst for olefin polymerization, a preparation method of the catalyst and an olefin polymerization method. The catalyst is a coordination compound and has a structure shown in a formula (1), and L is selected from O, S or-NH-; m is selected from Ti, Zr, Hf, Cr, Ni or Fe; x is selected from a substituted or unsubstituted C1-C20 oxygen-containing group, F, Cl, Br or I; n is an integer of 2-6; and m is an integer of 1-4. The catalyst can efficiently catalyze ethylene monomer homopolymerization to selectively prepare linear alpha-olefin, is especially suitable for selective preparation of 1-hexene and / or 1-octene, has high catalytic activity and good catalytic stability, and can co-produce 1-hexene and 1-octene with high selectivity. # imgabs0 #

Description

Technical Field

[0001] The present invention relates to the technical field of olefin polymerization, and in particular to a catalyst for olefin polymerization, a preparation method thereof and an olefin polymerization method. Background Art

[0002] Linear alpha-olefins (LAOs) have a wide range of industrial applications, mainly in the production of polyolefins, lubricants and fine chemicals, with an annual global demand of more than 4 million tons. Although manufacturers such as Phillips and Union Carbide provide more than one-third of the global production capacity, the traditional LAO preparation method usually results in a normal distribution of olefin products, with only a small proportion of olefin production in each fraction. Olefins of different carbon chain lengths have different uses. For example, 1-hexene (1-C6) and 1-octene (1-C8) are high-quality comonomers for the preparation of linear low-density polyethylene (LLDPE). In addition, 1-decene (1-C10) is used as a comonomer and intermediate, and its market is growing rapidly, while other olefin segments are almost stagnant or even shrinking. Therefore, this imbalance in olefin demand has aroused great interest in the selective production of linear olefins. The highly selective catalytic production of ethylene to obtain a single alpha-olefin with a specific carbon number is of great significance to both academia and industry.

[0003] At present, the technology of preparing 1-hexene by selective trimerization of ethylene is relatively mature, which can achieve 98.1% 1-hexene selectivity and 160kg / gCr -1 h -1 The polymerization activity of ethylene tetramerization is high, but the technology of preparing 1-octene by ethylene tetramerization still faces great difficulties. Although the existing ethylene tetramerization system has shown high catalytic activity, the selectivity of the product 1-octene is still difficult to control. Bollmann et al. (Ethylene tetramerization: a new route to produce 1-octene with exceptionally high selectivities. J. Am. Chem. Soc. 2004, 126 (45), 14712-14713) used (R 2 ) 2 PN(R1)P(R 2 ) 2The catalyst composed of (PNP) ligand, chromium trichloride and methylaluminoxane (MAO) catalyzes the polymerization of ethylene. The selectivity of 1-octene reaches up to about 70wt%, and the selectivity of terminal olefins is above 90%. However, the overall selectivity of the ethylene tetramerization system does not reach the selectivity of ethylene trimerization (over 90%), and there are many by-products, which brings difficulties to the separation of subsequent products. It is still a huge challenge to produce 1-octene using ethylene with high activity and high selectivity.

[0004] Therefore, it is urgent to develop highly active and highly selective catalysts that can be used to catalyze ethylene polymerization. Summary of the invention

[0005] The present invention aims at the problem that the existing ethylene polymerization catalyst has poor selectivity of 1-hexene and / or 1-octene and many by-products in the ethylene selective polymerization reaction, and provides a catalyst for olefin polymerization and a preparation method thereof and an olefin polymerization method. The catalyst can significantly improve the selectivity of 1-hexene and 1-octene products in the ethylene selective polymerization, and prepare high-purity 1-hexene and 1-octene.

[0006] To achieve the above object, the present invention provides a catalyst for olefin polymerization in a first aspect. The catalyst is a coordination compound having a structure shown in formula (1):

[0007]

[0008] Wherein, L is selected from O, S or -NH-; M is selected from Ti, Zr, Hf, Cr, Ni or Fe; X is selected from substituted or unsubstituted C 1 -C 20 Oxygen-containing groups, F, Cl, Br or I; n is an integer of 2-6; m is an integer of 1-4;

[0009] R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7 , R 8 , R 9 , R 10 , R 11 , R 12 Each group is independently selected from H, halogen, substituted or unsubstituted C 1 -C 10 Alkyl, substituted or unsubstituted C 3 -C 8 Cycloalkyl, substituted or unsubstituted C 2 -C 10 Alkenyl, substituted or unsubstituted C 2-C 10 Alkynyl, substituted or unsubstituted C 6 -C 30 The aromatic group.

[0010] The second aspect of the present invention provides a method for preparing the catalyst for olefin polymerization described in the first aspect, the method comprising:

[0011] In the presence of a solvent, a transition metal precursor is reacted with a ligand to obtain a catalyst; wherein the ligand has a structure shown in formula (2),

[0012]

[0013] Wherein, L is selected from O, S or -NH-; m is an integer of 1-4;

[0014] R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7 , R 8 , R 9 , R 10 , R 11 , R 12 Each group is independently selected from H, halogen, substituted or unsubstituted C 1 -C 10 Alkyl, substituted or unsubstituted C 3 -C 8 Cycloalkyl, substituted or unsubstituted C 2 -C 10 Alkenyl, substituted or unsubstituted C 2 -C 10 Alkynyl, substituted or unsubstituted C 6 -C 30 The aromatic group.

[0015] The third aspect of the present invention provides a method for olefin polymerization, comprising: polymerizing olefin in the presence of a catalyst system to obtain a polymerization product;

[0016] Wherein, the catalyst system contains the catalyst described in the first aspect above.

[0017] The catalyst provided by the present invention can efficiently catalyze the homopolymerization of ethylene monomers to selectively prepare linear α-olefins, and is particularly suitable for selectively preparing 1-hexene and / or 1-octene. The catalyst has high catalytic activity, good catalytic stability, and long service life, and can co-produce 1-hexene and 1-octene with high selectivity. DETAILED DESCRIPTION

[0018] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0019] The first aspect of the present invention provides a catalyst for olefin polymerization, which is a coordination compound having a structure shown in formula (1):

[0020]

[0021] Wherein, L is selected from O, S or -NH-; M is selected from Ti, Zr, Hf, Cr, Ni or Fe; X is selected from substituted or unsubstituted C1-C20 oxygen-containing groups, F, Cl, Br or I; n is an integer of 2-6; m is an integer of 1-4;

[0022] R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7 , R 8 , R 9 , R 10 , R 11 , R 12 Each group is independently selected from H, halogen, substituted or unsubstituted C 1 -C 10 Alkyl, substituted or unsubstituted C 3 -C 8 Cycloalkyl, substituted or unsubstituted C 2 -C 10 Alkenyl, substituted or unsubstituted C 2 -C 10 Alkynyl, substituted or unsubstituted C 6 -C 30 The aromatic group.

[0023] The catalyst provided by the present invention can efficiently catalyze the homopolymerization of ethylene monomers to selectively prepare linear α-olefins, and is particularly suitable for the highly selective preparation of 1-hexene and / or 1-octene. There are few by-products in the polymerization process, which can greatly facilitate the subsequent product separation and thus greatly reduce the energy consumption of product separation. The catalytic activity of the catalyst is (0.1-20)×10 6 g / (mol Cr·h), good catalytic stability, long service life, and can co-produce 1-hexene and 1-octene with high selectivity at a yield of more than 90wt%.

[0024] According to the present invention, the catalyst satisfies the above structure and composition. In formula (1), preferably, L is S or -NH-, which enables the catalyst to have higher selectivity for 1-hexene and 1-octene in the polymerization reaction of ethylene monomer.

[0025] According to the present invention, in formula (1), preferably, M is selected from Cr and Ni, which can make the catalyst have high catalytic activity and excellent 1-hexene and 1-octene selectivity in the polymerization reaction of ethylene monomer. Further preferably, M is Cr, which can make the catalyst have higher 1-hexene and 1-octene selectivity in the polymerization reaction of ethylene monomer.

[0026] According to the present invention, in formula (1), preferably, n is an integer of 2-4, and m is an integer of 1-3, which enables the catalyst to catalyze the polymerization of ethylene monomer with higher activity and high selectivity to prepare 1-hexene and 1-octene.

[0027] According to the present invention, in formula (1), preferably, R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7 , R 8 , R 9 , R 10 , R 11 , R 12 Each group is independently selected from H, halogen, substituted or unsubstituted C 1 -C 4 Alkyl, substituted or unsubstituted C 3 -C 6 Cycloalkyl, substituted or unsubstituted C 2 -C 4 Alkenyl, substituted or unsubstituted C 2 -C 4 Alkynyl, substituted or unsubstituted C 6 -C 15 The aromatic group can make the catalyst have high catalytic activity and higher selectivity of 1-hexene and 1-octene in the polymerization reaction of ethylene monomer.

[0028] According to the present invention, in formula (1), for R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7 , R 8 , R 9 , R 10 , R11 , R 12 Selected from substituted or unsubstituted C 1 -C 10 Alkyl, substituted or unsubstituted C 3 -C 8 Cycloalkyl, substituted or unsubstituted C 2 -C 10 Alkenyl, substituted or unsubstituted C 2 -C 10 Alkynyl, substituted or unsubstituted C 6 -C 30 In the case of an aromatic group, R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7 , R 8 , R 9 , R 10 , R 11 , R 12 Each independently may also contain 1 to 3 substituents, which can make the catalyst have higher selectivity of 1-hexene and 1-octene in the polymerization reaction of ethylene monomer.

[0029] Preferably, the substituent may be selected from allyl, halogen, nitro, -C(O)OR 13 、-(O)COR 14 、-C(O)NR 15 ; Among them, R 13 , R 14 , R 15 Each independently selected from H, C 1 -C 10 Alkyl, C 3 -C 8 Cycloalkyl, C 2 -C 10 The alkenyl group, C 2 -C 10 Alkynyl or C 6 -C 30 The aryl group is more preferably C 1 -C 10 Alkyl or C 6 -C 30 The aromatic group.

[0030] In the present invention, the halogen refers to F, Cl, Br or I.

[0031] According to some preferred embodiments of the present invention, the catalyst has at least one of the structures shown by formula (1-1), formula (1-2), formula (1-3), formula (1-4), formula (1-5), formula (1-6), formula (1-7), formula (1-8), formula (1-9), formula (1-10), formula (1-11), formula (1-12), formula (1-13), formula (1-14) and formula (1-15), and can have higher catalytic activity and better catalytic stability.

[0032]

[0033]

[0034] The catalyst provided by the present invention can efficiently catalyze the homopolymerization of ethylene monomers to selectively prepare linear α-olefins, and is particularly suitable for selectively preparing 1-hexene and / or 1-octene. The catalyst has high catalytic activity, which can reach (0.1-20)×10 6 g / (mol Cr·h), and has good catalytic stability and long service life. It can co-produce 1-hexene and 1-octene with high selectivity, and can prepare 1-hexene and 1-octene in different proportions according to different substituent groups in the catalyst or different polymerization temperatures, so that the weight ratio of the product 1-hexene / 1-octene can be flexibly adjusted within the range of (0.5-3):1, and the sum of the mass fractions of 1-hexene and 1-octene in the polymerization product is above 90%.

[0035] The second aspect of the present invention provides a method for preparing the catalyst for olefin polymerization described in the first aspect, the method comprising:

[0036] In the presence of a solvent, a transition metal precursor is reacted with a ligand to obtain a catalyst; wherein the ligand has a structure shown in formula (2),

[0037]

[0038] Wherein, L is selected from O, S or -NH-; m is an integer of 1-4;

[0039] R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7 , R 8 , R 9 , R 10 , R 11 , R 12 Each group is independently selected from H, halogen, substituted or unsubstituted C 1 -C 10Alkyl, substituted or unsubstituted C 3 -C 8 Cycloalkyl, substituted or unsubstituted C 2 -C 10 Alkenyl, substituted or unsubstituted C 2 -C 10 Alkynyl, substituted or unsubstituted C 6 -C 30 The aromatic group.

[0040] According to the present invention, in the preparation method, the transition metal precursor can be selected from chromium compounds or nickel compounds, preferably chromium compounds.

[0041] According to the present invention, in the preparation method, the chromium compound can be selected from chromium (III) acetylacetonate, chromium (III) tris(hexafluoroacetylacetonate), chromium (III) acetate, chromium (III) tris(trifluoroacetate), chromium (III) butyrate, chromium (III) pivalate, chromium (III) laurate, chromium (III) stearate, chromium (III) oxalate, chromium (III) tris(2-ethylhexanoate), chromium (III) chloride, chromium (III) bromide, chromium (III) fluoride, chromium (III) acetate, chromium (II) butyrate, chromium (II) pivalate, chromium (II) laurate, chromium (II) stearate, chromium (II) oxalate, chromium (II) chloride, chromium (II) bromide, chromium (II) fluoride, chromium (IV) bromide and CrCl 3 (THF) 3 At least one of the above can make the prepared catalyst have high catalytic activity and can catalyze the polymerization of ethylene monomer to prepare 1-hexene and 1-octene with high selectivity.

[0042] According to the present invention, in the preparation method, preferably, the nickel compound can be selected from at least one of nickel (II) chloride, nickel (II) acetate, nickel (II) bromide, nickel (II) fluoride and nickel (II) acetylacetonate.

[0043] According to the present invention, in the preparation method, the ligand satisfies the above structure and composition. In formula (2), preferably, L is S or -NH-, which enables the prepared catalyst to have higher selectivity for 1-hexene and 1-octene in the polymerization reaction of ethylene monomer.

[0044] According to the present invention, in the ligand represented by formula (2), preferably, n is an integer of 2-4, and m is an integer of 1-3, which enables the prepared catalyst to have a higher activity in catalyzing the polymerization of ethylene monomers to prepare 1-hexene and 1-octene with high selectivity.

[0045] According to the present invention, in the ligand represented by formula (2), preferably, R 1 , R 2 , R3 , R 4 , R 5 , R 6 , R 7 , R 8 , R 9 , R 10 , R 11 , R 12 Each group is independently selected from H, halogen, substituted or unsubstituted C 1 -C 4 Alkyl, substituted or unsubstituted C 3 -C 6 Cycloalkyl, substituted or unsubstituted C 2 -C 4 Alkenyl, substituted or unsubstituted C 2 -C 4 Alkynyl, substituted or unsubstituted C 6 -C 15 The aromatic group can make the prepared catalyst have high catalytic activity and higher selectivity for 1-hexene and 1-octene in the polymerization reaction of ethylene monomer.

[0046] According to the present invention, in the ligand represented by formula (2), for R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7 , R 8 , R 9 , R 10 , R 11 , R 12 is selected from substituted or unsubstituted C 1 -C 10 Alkyl, substituted or unsubstituted C 3 -C 8 Cycloalkyl, substituted or unsubstituted C 2 -C 10 Alkenyl, substituted or unsubstituted C 2 -C 10 Alkynyl, substituted or unsubstituted C 6 -C 30 In the case of an aromatic group, R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7 , R 8 , R 9 , R 10 , R 11 , R12 Each independently may also contain 1 to 3 substituents, which can make the prepared catalyst have higher selectivity of 1-hexene and 1-octene in the polymerization reaction of ethylene monomer.

[0047] According to the present invention, preferably, the substituent can be selected from allyl, halogen, nitro, -C(O)OR 13 、-(O)COR 14 、-C(O)NR 15 ; Among them, R 13 , R 14 , R 15 Each independently selected from H, C 1 -C 10 Alkyl, C 3 -C 8 Cycloalkyl, C 2 -C 10 The alkenyl group, C 2 -C 10 Alkynyl or C 6 -C 30 The aryl group is more preferably C 1 -C 10 Alkyl or C 6 -C 30 The aromatic group.

[0048] In the present invention, the halogen refers to F, Cl, Br or I.

[0049] According to some preferred embodiments of the present invention, the ligand has at least one of the structures shown by formula (2-1), formula (2-2), formula (2-3), formula (2-4), formula (2-5), formula (2-6), formula (2-7), formula (2-8), formula (2-9), formula (2-10), formula (2-11), formula (2-12), formula (2-13) and formula (2-14), which can make the prepared catalyst have higher catalytic activity and better catalytic stability, and have higher selectivity for 1-hexene and 1-octene in the polymerization reaction of ethylene monomer.

[0050]

[0051]

[0052] In the present invention, the ligand represented by formula (2-1) can be prepared by the following method:

[0053] In a 200mL schlenk bottle, ultra-dry tetrahydrofuran (100mL) was added, and 2-diphenylphosphine ethanethiol (5.0g, 20.3mmol) was added. After it was completely dissolved, sodium hydroxide (2.0g, 50.8mmol) was added, and the mixture was reacted at 50°C for 3h. Then, 2-bromomethylpyridine (20.3mmol) was added, and the mixture was reacted at 50°C for 12h. A large amount of white precipitate appeared in the reaction system. After the reaction was completed by nuclear magnetic resonance tracking, the reaction system was passed through diatomaceous earth, dried and concentrated by evaporation, and chromatographed on a silica gel column (column moistened with triethylamine, ethyl acetate / petroleum ether = 1 / 20) to obtain a yellow solid, which was the ligand represented by formula (2-1).

[0054] By adopting the above preparation steps and replacing the raw material monomers, the ligands shown in formula (2-2), formula (2-3), formula (2-4), formula (2-5), formula (2-6), formula (2-7), formula (2-8), formula (2-9), formula (2-10), formula (2-11), formula (2-12), formula (2-13), and formula (2-14) can be prepared respectively. The raw material monomers and the corresponding ligands prepared are shown in Table 1.

[0055] Table 1

[0056]

[0057]

[0058]

[0059] According to the present invention, in the preparation method, the solvent is an organic solvent, which can be selected from at least one of tetrahydrofuran (THF), toluene, dichloromethane and methyl tert-butyl ether.

[0060] According to the present invention, in the preparation method, the molar ratio of the transition metal precursor:ligand is (0.1-10):1, preferably (0.3-3):1.

[0061] According to the present invention, in the preparation method, the reaction conditions include: temperature of 30-90°C, time of 5-12h. Preferably, the reaction temperature is 30-70°C, time of 7-10h.

[0062] The third aspect of the present invention provides a method for olefin polymerization, comprising: polymerizing olefin in the presence of a catalyst system to obtain a polymerization product;

[0063] Wherein, the catalyst system contains the catalyst described in the first aspect above.

[0064] According to the present invention, in the method for olefin polymerization, the polymerization reaction may include: ethylene oligomerization to prepare linear α-olefins or ethylene polymerization to prepare linear / branched polyethylene.

[0065] According to the present invention, the catalyst system may contain a co-catalyst. The co-catalyst may be selected from at least one of alkyl aluminum, halogen-substituted alkyl aluminum, alkyl aluminoxane and halogen-substituted alkoxy aluminum. Preferably, in the catalyst system, the molar ratio of the Al element in the co-catalyst to the M element (Ti, Zr, Hf, Cr, Ni or Fe) in the catalyst provided by the present invention is (10-10000):1.

[0066] According to the present invention, preferably, the conditions of the polymerization reaction include: a temperature of 0-100° C. and a pressure of 1-7 MPa.

[0067] According to the present invention, the process of the polymerization reaction is relatively broad, for example, it can be slurry polymerization, gas phase polymerization, solution polymerization, etc.

[0068] In the present invention, preferably, the olefin polymerization method is used to prepare 1-hexene and / or 1-octene, and during the polymerization process, the catalyst activity can reach (0.1-20)×10 6 g / (mol Cr·h), and good catalytic stability, and can co-produce 1-hexene and 1-octene with high selectivity. By changing the substituent groups in the catalyst or changing the polymerization temperature, the weight ratio of the product 1-hexene / 1-octene can be flexibly adjusted in the range of (0.5-3):1, and the sum of the mass fractions of 1-hexene and 1-octene in the polymerization product is above 90%.

[0069] The present invention will be described in detail below by way of examples. In the following preparation examples and embodiments, unless otherwise specified, all materials used are common commercially available products.

[0070] Preparation Example 1

[0071] This preparation example is used to illustrate the preparation of the ligand:

[0072]

[0073] Ultra-dry tetrahydrofuran (100 mL) was added to a 200 mL schlenk bottle, and 2-diphenylphosphine ethanethiol (5.0 g, 20.3 mmol) was added. After it was completely dissolved, sodium hydroxide (2.0 g, 50.8 mmol) was added, and the mixture was reacted at 50° C. for 3 h. Then, 2-bromomethylpyridine (20.3 mmol) was added, and the mixture was reacted at 50° C. for 12 h. A large amount of white precipitate appeared in the reaction system. After the reaction was completed by nuclear magnetic resonance tracking, the reaction system was passed through diatomaceous earth, dried and concentrated by evaporation, and chromatographed on a silica gel column (column moistened with triethylamine, ethyl acetate / petroleum ether = 1 / 20) to obtain a yellow solid (referred to as ligand L1).

[0074] The structure of L1 was characterized by H NMR spectroscopy. The results are shown in Table 2.

[0075] Preparation Example 2-14

[0076] This preparation example is used to illustrate the preparation of the ligand:

[0077] According to the method of Preparation Example 1, the corresponding raw materials were replaced to prepare ligands L2-L14. The structures and structural characterization results of ligands L2-L14 are shown in Table 2.

[0078] Table 2

[0079]

[0080]

[0081]

[0082]

[0083] Example 1

[0084] This example is used to illustrate the preparation of the catalyst:

[0085] 0.1 mmol ligand (L1) and 0.1 mmol CrCl 3 (THF) 3 The reaction was carried out in THF at 30°C for 10 h, and the solvent was removed to obtain a catalyst (denoted as C1, C1 having a structure shown in formula (1-1)), and C1 was prepared into a toluene solution with a concentration of 10 μmol / mL.

[0086] Embodiment 2-5

[0087] This example is used to illustrate the preparation of the catalyst:

[0088] The method of Preparation Example 1 was followed, except that ligand L1 was replaced with ligands L2-L5 in equal molar amounts. Other conditions were the same as in Example 1 to obtain catalysts (denoted as C2-C5, C2-C5 having structures shown in Formula (1-1) to Formula (1-5) respectively), and C2-C5 were prepared into toluene solutions with a concentration of 10 μmol / mL.

[0089] Example 6

[0090] This example is used to illustrate the preparation of the catalyst:

[0091] 0.1mmol ligand (L6) and 0.1mmol Cr(acac) 3The reaction was carried out in THF at 30°C for 10 h, and the solvent was removed to obtain a catalyst (denoted as C6, C6 having a structure shown in formula (1-6)), and C6 was prepared into a toluene solution with a concentration of 10 μmol / mL.

[0092] Example 7

[0093] This example is used to illustrate the preparation of the catalyst:

[0094] 0.1 mmol ligand (L1) and 0.1 mmol NiCl 2 The reaction was carried out in THF at 30°C for 10 h, and the solvent was removed to obtain a catalyst (denoted as C7, C7 having a structure shown in formula (1-7)), and C7 was prepared into a toluene solution with a concentration of 10 μmol / mL.

[0095] Embodiment 8-15

[0096] This example is used to illustrate the preparation of the catalyst:

[0097] The method of Preparation Example 1 was followed, except that ligand L1 was replaced with ligands L7-L14 in equal molar amounts. Other conditions were the same as in Example 1, to obtain catalysts (denoted as C8-C15, C8-C15 having structures shown in Formula (1-8) to Formula (1-15) respectively), and C8-C15 were prepared into toluene solutions with a concentration of 10 μmol / mL.

[0098] Comparative Example 1

[0099] This comparative example is used to illustrate the preparation of the catalyst:

[0100] 0.1 mmol ligand and 0.1mmol CrCl 3 (THF) 3 The reaction was carried out in THF at 30°C for 10 h, and the solvent was removed to obtain a catalyst (denoted as D1), and D1 was prepared into a toluene solution with a concentration of 10 μmol / mL.

[0101] Test Case

[0102] The catalyst samples C1-C15 prepared in the above Examples 1-15 and the catalyst sample D1 prepared in Comparative Example 1 were used to carry out high pressure ethylene polymerization to prepare 1-hexene and 1-octene. The test method is as follows:

[0103] The reaction was carried out in a 1000ml stainless steel high-pressure reactor. Before the reaction, the system was pumped for 2h under 120°C oil bath heating with an oil pump to ensure that the system was strictly anhydrous, replaced with nitrogen three times, cooled to 50°C, and 500ml toluene, 3mmol methylaluminoxane (1.5mol / L, Al / Cr ratio of 3000), and catalyst C1-C16 were added. The injection port was closed immediately after the feeding was completed; the ethylene gauge pressure was adjusted to 4MPa to start the reaction (reaction temperature was 50°C) and the reaction was carried out for 1h; after the reaction was completed, the air inlet valve was closed, the reaction system was cooled to 0°C, weighed and heptane was added to the reactor as an internal standard (the activity of each catalyst sample was calculated using the internal standard method), a small amount of product was taken with a dropper after mixing, filtered with diatomaceous earth, and the amount of 1-hexene and 1-octene products was determined by gas chromatography (GC). If there are polymers in the product, pour the reaction solution into a conical flask, add hydrochloric acid ethanol solution to quench, stir for 1 hour, heat the filtered solid to 70°C in a vacuum drying oven, dry for more than 12 hours until constant weight, weigh and perform other analyses.

[0104] The reaction conditions and results are shown in Table 3.

[0105] Table 3

[0106]

[0107] It can be seen from the data in Table 3 that the catalyst provided by the present invention can catalyze the polymerization of ethylene monomer with high activity and high selectivity to co-produce 1-hexene and 1-octene, and has good catalytic stability (the catalyst activity of catalyst C1 is still higher than 8×10 6 g / (mol Cr·h)), the sum of the mass fractions of 1-hexene and 1-octene in the polymerization product is above 90%, and the weight ratio of 1-hexene / 1-octene in the product can be flexibly adjusted in the range of (0.5-3):1.

[0108] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. A catalyst for olefin polymerization, the catalyst being a coordination compound having a structure shown in formula (1), in, L is selected from O, S or -NH-; M is selected from Ti, Zr, Hf, Cr, Ni or Fe; X is selected from substituted or unsubstituted C 1 -C 20 Oxygen-containing groups, F, Cl, Br or I; n is an integer of 2-6; m is an integer of 1-4; R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7 , R 8 , R 9 , R 10 , R 11 , R 12 Each group is independently selected from H, halogen, substituted or unsubstituted C 1 -C 10 Alkyl, substituted or unsubstituted C 3 -C 8 Cycloalkyl, substituted or unsubstituted C 2 -C 10 Alkenyl, substituted or unsubstituted C 2 -C 10 Alkynyl, substituted or unsubstituted C 6 -C 30 The aromatic group.

2. The catalyst according to claim 1, in, L is S or -NH-; M is selected from Cr or Ni; X is Cl; and / or, n is an integer of 2-4; m is an integer of 1-3; and / or, R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7 , R 8 , R 9 , R 10 , R 11 , R 12 Each group is independently selected from H, halogen, substituted or unsubstituted C 1 -C 4 Alkyl, substituted or unsubstituted C 3 -C 6 Cycloalkyl, substituted or unsubstituted C 2 -C 4 Alkenyl, substituted or unsubstituted C 2 -C 4 Alkynyl, substituted or unsubstituted C 6 -C 15 Aryl.

3. The catalyst according to claim 1 or 2, in, The alkyl, cycloalkyl, alkenyl, alkynyl and aryl groups optionally contain 1 to 3 substituents; Preferably, the substituent is selected from allyl, halogen, nitro, -C(O)OR 13 、-(O)COR 14 or -C(O)NR 15 ; Among them, R 13 , R 14 , R 15 Each independently selected from H, C 1 -C 10 Alkyl, C 3 -C 8 Cycloalkyl, C 2 -C 10 The alkenyl group, C 2 -C 10 Alkynyl or C 6 -C 30 The aromatic group.

4. The catalyst according to any one of claims 1 to 3, in, The catalyst has at least one of the structures represented by formula (1-1), formula (1-2), formula (1-3), formula (1-4), formula (1-5), formula (1-6), formula (1-7), formula (1-8), formula (1-9), formula (1-10), formula (1-11), formula (1-12), formula (1-13), formula (1-14) and formula (1-15), 5. A method for preparing a catalyst for olefin polymerization according to any one of claims 1 to 4, include: In the presence of a solvent, a transition metal precursor is reacted with a ligand to obtain a catalyst; wherein the ligand has a structure shown in formula (2), Wherein, L is selected from O, S or -NH-; m is an integer of 1-4; R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7 , R 8 , R 9 , R 10 , R 11 , R 12 Each group is independently selected from H, halogen, substituted or unsubstituted C 1 -C 10 Alkyl, substituted or unsubstituted C 3 -C 8 Cycloalkyl, substituted or unsubstituted C 2 -C 10 Alkenyl, substituted or unsubstituted C 2 -C 10 Alkynyl, substituted or unsubstituted C 6 -C 30 The aromatic group.

6. The preparation method according to claim 5, in, The transition metal precursor is selected from chromium compounds or nickel compounds; Preferably, the chromium compound is selected from chromium (III) acetylacetonate, chromium (III) tris(hexafluoroacetylacetonate), chromium (III) acetate, chromium (III) tris(trifluoroacetate), chromium (III) butyrate, chromium (III) pivalate, chromium (III) laurate, chromium (III) stearate, chromium (III) oxalate, chromium (III) tris(2-ethylhexanoate), chromium (III) chloride, chromium (III) bromide, chromium (III) fluoride, chromium (III) acetate, chromium (II) butyrate, chromium (II) pivalate, chromium (II) laurate, chromium (II) stearate, chromium (II) oxalate, chromium (II) chloride, chromium (II) bromide, chromium (II) fluoride, chromium (IV) bromide and CrCl 3 (THF) 3 At least one of; Preferably, the nickel compound is selected from at least one of nickel (II) chloride, nickel (II) acetate, nickel (II) bromide, nickel (II) fluoride and nickel (II) acetylacetonate.

7. The preparation method according to claim 5 or 6, in, The molar ratio of the transition metal precursor to the ligand is (0.1-10):1, preferably (0.3-3):1; And / or, the reaction conditions include: temperature of 30-90°C, preferably 30-70°C; time of 5-12h, preferably 7-10h.

8. A method for polymerizing olefins, include: In the presence of a catalyst system, the olefin is polymerized to obtain a polymer product; Wherein, the catalyst system contains the catalyst described in any one of claims 1-4.

9. The method according to claim 8, in, The polymerization reaction includes: ethylene oligomerization to prepare linear α-olefins or ethylene polymerization to prepare linear / branched polyethylene.

10. The method according to claim 9, in, The polymerization reaction conditions include: temperature of 0-100° C. and pressure of 1-7 MPa.

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