Main catalyst for preparing alpha-olefin through wide-distribution oligomerization of ethylene as well as preparation method, catalyst composition and application of main catalyst

Abstract

The invention provides a main catalyst for preparing alpha-olefin through wide-distribution oligomerization of ethylene as well as a preparation method, a catalyst composition and application of the main catalyst. The main catalyst is combined with other auxiliaries, cocatalysts and activators to obtain an efficient five-way catalyst system, and through the synergistic effect of the five components, the catalyst system not only shows high catalyst activity and high alpha-olefin selectivity, but also generates extremely low high polymer content.

Description

Technical Field

[0001] This invention belongs to the field of homogeneous catalyst technology for ethylene broad-distribution oligomerization reaction, and relates to a main catalyst for the preparation of α-olefins by ethylene broad-distribution oligomerization, its preparation method, catalyst composition and application, and particularly to a high-efficiency catalyst composition for ethylene broad-distribution oligomerization and its application method. Background Technology

[0002] Linear α-olefins are an important class of organic chemical raw materials, mainly produced through ethylene oligomerization. They can be used as comonomers for the production of high-performance linear low-density polyethylene (LLDPE), high-density polyethylene (HDPE), and polyolefin elastomers (POE). They can also be used as raw materials for the production of high-end lubricants, plasticizers, surfactants, and other fine chemicals.

[0003] Currently, C4 to C6 can be produced using oligomerization with ethylene as a raw material. 40 Even-numbered carbon linear α-olefins, wherein C4~C 24 Linear α-olefins have high commercial value. In particular, C... 8~ C 12 The downstream applications of α-olefins include polyalphaolefins (PAO) and alkylbenzenes, representing the second largest consumer market for linear α-olefins. These mainly include polymers of 1-decene, 1-octene, and 1-dodecene. Research reports indicate that C... 14~ C 18 Linear α-olefins are widely used in the synthesis of surfactants. Surfactants prepared from them exhibit good surface activity and biodegradability, making them the preferred raw material for preparing environmentally friendly surfactants. However, C 8~ C 18 The lack of large-scale industrial-scale olefin production facilities severely restricts the development of downstream chemical and materials industries. Therefore, developing technologies for the preparation of high-carbon α-olefins through ethylene wide-distribution oligomerization is of great significance to further promote the industrialization of high-carbon α-olefins.

[0004] Currently, the main industrial method for preparing high-carbon-chain α-olefins is the ethylene oligomerization method. This method uses only ethylene as a raw material and can synthesize α-olefin products in one step under the action of a catalyst. By adjusting the catalyst structure, the type of co-catalyst, and the polymerization conditions, target products with different carbon chain lengths can be obtained. Furthermore, the α-olefins synthesized by this method have advantages such as high linear α-olefin content, low isomerization, and easy product separation, making it a focus of research. The core element in the ethylene oligomerization process for preparing α-olefins is the catalyst. Currently, existing catalytic systems mainly use catalysts such as Ni-Al-P and ZrCl4-Al2R2X3-Am3, but the reaction temperature and pressure are extremely high, posing a significant explosion risk. Summary of the Invention

[0005] In view of this, the purpose of this invention is to provide a main catalyst for the broad-distribution oligomerization of ethylene to prepare α-olefins, its preparation method, catalyst composition, and applications. This invention provides a main catalyst incorporating a pyridine-based binuclear ligand, further combined with an auxiliary agent B, two co-catalysts C-1 and C-2, and an activator D. This results in a catalyst composition exhibiting unprecedented high activity, high α-olefin selectivity, and extremely low polymer content. Furthermore, this catalyst composition can withstand high reaction temperatures, enabling long-term stable operation of continuous reactors, thus possessing significant economic and industrial implications.

[0006] To achieve this objective, the present invention adopts the following technical solution:

[0007] In a first aspect, the present invention provides a main catalyst for the broad-distribution oligomerization of ethylene to prepare α-olefins, having the structure of Formula I:

[0008] Formula I;

[0009] R1 and R2 are each independently selected from hydrogen, substituted or unsubstituted C1-C6 alkyl groups or substituted or unsubstituted C6-C15 aryl groups;

[0010] R3 is selected from halogens, C1-C3 alkanes, or C1-C3 haloalkyl groups.

[0011] Preferably, R1 and R2 are each independently selected from one or more of hydrogen, methyl, ethyl, isopropyl or phenyl.

[0012] Preferably, R3 is selected from one or more of F, Cl, Br, methyl, ethyl, and trifluoromethyl.

[0013] Preferably, the main catalyst is selected from any one of the following formulas A-1 to A-8:

[0014] Formula A-1;

[0015] Formula A-2;

[0016] Formula A-3;

[0017] Formula A-4;

[0018] Formula A-5;

[0019] Formula A-6;

[0020] Formula A-7;

[0021] Formula A-8.

[0022] Secondly, the present invention provides a method for preparing the above-mentioned main catalyst, comprising the following steps:

[0023] S1: Provides the compound shown in Formula II;

[0024] S2: By complexing the compound shown in Formula II with an iron source in the presence of a solvent, the main catalyst Formula I can be obtained;

[0025] Formula II.

[0026] The iron source is selected from divalent iron halide; the divalent iron halide is selected from any one or more of anhydrous ferric chloride, ferric chloride hexahydrate, or FeCl2.DME (wherein, DME is ethylene glycol dimethyl ether, and FeCl2.DME refers to a complex of FeCl2 and ethylene glycol dimethyl ether).

[0027] Preferably, the solvent is selected from tetrahydrofuran, toluene, xylene, dichloromethane, or diethyl ether.

[0028] Preferably, the molar ratio of the compound represented by Formula II to the iron source is 1:1 to 1:1.2.

[0029] Preferably, the complexation reaction is carried out at room temperature for 12 to 24 hours.

[0030] Preferably, the compound represented by Formula II is prepared according to the following method:

[0031] ( The same or different diacylpyridines (i.e., R1 and R2 can be the same or different) are each reacted with 3,5-dichloroaniline in a solvent in the presence of a catalyst to produce formula III and formula IV. The synthetic route is as follows.

[0032] Formula III;

[0033] Formula IV;

[0034] ( ) will be the step ( Formula III obtained from this reaction, along with substituent-containing benzidine, undergoes a ketamine condensation reaction in a solvent in the presence of a catalyst to yield Formula V. The synthetic route is as follows:

[0035] Formula V;

[0036] ( ) will be the step ( Equation V obtained and steps ( The obtained formula IV can undergo a ketone-amine condensation reaction in a solvent in the presence of a catalyst to obtain ligand II. The synthetic route is as follows:

[0037] Formula II.

[0038] Preferably, step ( The solvent is selected from one or more of methanol, ethanol, acetic acid, toluene, or dichloromethane; the catalyst is selected from one or more of formic acid, acetic acid, hydrochloric acid, p-toluenesulfonic acid, or zinc chloride.

[0039] Preferably, the molar ratio of 3,5-dichloroaniline to diacylpyridine is 1:2~3.

[0040] Preferably, the molar ratio of the compound represented by Formula III to the substituent-containing benzidine is 1:2 to 4.

[0041] Preferably, the molar ratio of the compound represented by Formula V to the compound represented by Formula IV is 1:2~3.

[0042] Preferably, the reaction temperature of the ketone-amine condensation reaction is 50~120℃; the ketone-amine condensation reaction is carried out under reflux conditions for 8~16 h.

[0043] In some embodiments of the present invention, the catalyst ligand represented by Formula II is selected from any one of Formulas II-1 to II-8:

[0044] Formula II-1;

[0045] Formula II-2;

[0046] Formula II-3;

[0047] Formula II-4;

[0048] Formula II-5;

[0049] Formula II-6;

[0050] Formula II-7;

[0051] Formula II-8.

[0052] Thirdly, the present invention provides a catalyst composition for the preparation of α-olefins by ethylene oligomerization as described above, comprising a main catalyst A, an auxiliary agent B, a co-catalyst C-1, a co-catalyst C-2, and an activator D; wherein the main catalyst A is the main catalyst involved in the above technical solution; the auxiliary agent B is selected from perfluoroarylborates and / or perfluoroarylboranes; the co-catalyst C-1 is selected from alkylaluminum and / or alkylaluminum chloride; the co-catalyst C-2 is selected from any one or more of alkylaluminum, alkylaluminum chloride, alkylzinc, alkylmagnesium, or alkylmagnesium chloride; the activator D is selected from any one or more of haloalkanes, haloaromatics, or fatty alcohol polyoxyethylene ethers; the molar ratio of the main catalyst A, auxiliary agent B, co-catalyst C-1, co-catalyst C-2, and activator D is 1:(0.1~50):(10~1000):(10~200):(1~100).

[0053] Fourthly, the present invention provides an application of the main catalyst or catalyst composition involved in the above-mentioned technical solution in the preparation of α-olefins by broad-distribution oligomerization of ethylene.

[0054] Fifthly, the present invention provides a method for preparing α-olefins by using the above-mentioned catalyst composition for the broad-distribution oligomerization of ethylene, comprising the following steps:

[0055] Under vacuum conditions, a solution of the main catalyst A, auxiliary agent B, co-catalyst C-1, co-catalyst C-2, and activator D are mixed with the reaction solvent according to the specified ratio. The mixture is heated to the reaction temperature, and ethylene is introduced to the reaction pressure to carry out the polymerization reaction, thereby obtaining the broadly distributed oligomer α-olefin.

[0056] Preferably, the reaction temperature is 80~150 ℃.

[0057] Preferably, the reaction pressure is 3~6 MPa.

[0058] Preferably, the polymerization reaction takes 30 to 100 minutes.

[0059] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0060] This invention provides a catalyst ligand for the broad-distribution oligomerization of ethylene to prepare α-olefins. The catalyst ligand is a chlorinated binuclear pyridineimide type, having the structural formula shown in Formula ⅠⅠ. Based on this ligand, this invention provides an iron-based binuclear pyridineimide ligand compound having the structural formula shown in Formula Ⅰ. Using this as the main catalyst A, combined with other promoters, co-catalysts, and activators, a highly efficient five-component catalyst system is obtained. Through the synergistic effect of the above five components, this catalyst system not only exhibits high catalytic activity and high α-olefin selectivity, but also produces polymers with extremely low content.

[0061] Compared to existing literature, the five-membered catalyst system for the broad-distribution oligomerization of ethylene to prepare α-olefins provided by this invention uses ferric chloride as the main catalyst metal, which is less expensive, and the co-catalyst no longer uses expensive MAO or modified MAO. The catalytic activity for oligomerization can reach 1.0 × 10⁻⁶. 4 With a Kg / g(Fe)·h or higher, the selectivity of α-olefins can reach up to 98%. At the same time, this five-membered catalyst system has high activity and high selectivity while also producing extremely low polymers, which enables the reaction to run continuously for a long period of time. This gives the five-membered catalyst system a significant advantage in industrial processes and makes it more suitable for promotion and application in industrial production. Detailed Implementation

[0062] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0063] There are no particular restrictions on the source of any raw materials used in this invention; they can be purchased from the market or prepared and purified using conventional methods known to those skilled in the art.

[0064] All terms, abbreviations, and trademarks used in this invention are conventional terms, abbreviations, and trademarks in the field. Each term, abbreviation, and trademark is clear and distinct in its relevant application field, and those skilled in the art can understand it clearly, accurately, and uniquely based on the term, abbreviation, and trademark.

[0065] To address the significant catalytic hazards associated with the ethylene oligomerization method for preparing high-carbon-chain α-olefins in existing technologies, this invention provides a main catalyst for the broad-distribution oligomerization of ethylene to prepare α-olefins, having the structure of Formula I:

[0066] Formula I;

[0067] R1 and R2 are each independently selected from hydrogen, substituted or unsubstituted C1-C6 alkyl groups, or substituted or unsubstituted C6-C15 aryl groups; R1 and R2 may be the same or different;

[0068] R3 is selected from halogens, C1-C3 alkanes, or C1-C3 haloalkyl groups.

[0069] In the structure of Formula I above, the dashed lines represent the complexation bonds between the ligand and the main catalyst metal Fe.

[0070] In some embodiments of the present invention, the main catalyst has the structure of Formula I, wherein R1 and R2 are each preferably selected independently from one or more of hydrogen, methyl, ethyl, isopropyl or phenyl, more preferably one of methyl, ethyl and phenyl, and R1 and R2 are preferably the same; R3 is preferably selected from one or more of halogen, C1-C3 alkane or C1-C3 haloalkyl, more preferably one or more of F, Cl, Br, methyl, ethyl, trifluoromethyl.

[0071] In some specific embodiments of the present invention, the main catalyst is selected from any one of the following formulas A-1 to A-8:

[0072] Formula A-1;

[0073] Formula A-2;

[0074] Formula A-3;

[0075] Formula A-4;

[0076] Formula A-5;

[0077] Formula A-6;

[0078] Formula A-7;

[0079] Formula A-8.

[0080] The present invention also provides a method for preparing the above-mentioned main catalyst, which includes the following steps:

[0081] S1: Provides the compound shown in Formula II;

[0082] S2: The compound shown in Formula II below is reacted with an iron source in the presence of a solvent to obtain the main catalyst Formula I;

[0083] Formula II.

[0084] According to the present invention, a compound represented by Formula II is first provided.

[0085] In some embodiments of the present invention, the compound represented by Formula II is prepared according to the following method:

[0086] ( The diacylpyridines were each reacted with 3,5-dichloroaniline in a solvent in the presence of a catalyst to undergo a ketamine condensation reaction to generate formulas III and IV. The synthetic route is as follows:

[0087] Formula III;

[0088] Formula IV;

[0089] ( ) will be the step ( Formula III obtained from this reaction, along with benzidine, undergoes a ketamine condensation reaction in a solvent in the presence of a catalyst to yield Formula V. The synthetic route is as follows:

[0090] Formula V;

[0091] ( ) will be the step ( Equation V obtained and steps ( The obtained formula IV can undergo a ketamine condensation reaction in a solvent in the presence of a catalyst to obtain the ligand compound formula II. The synthetic route is as follows.

[0092] Formula II.

[0093] Among them, step ( The solvent described in the formula is selected from any one or more of methanol, ethanol, acetic acid, toluene, or dichloromethane; the catalyst is selected from one or more of formic acid, acetic acid, hydrochloric acid, p-toluenesulfonic acid, and zinc chloride; the molar ratio of 3,5-dichloroaniline to diacylpyridine is 1:2~3; the molar ratio of formula III to biphenyl diamine is 1:2~4; the molar ratio of formula V to formula IV is 1:2~3; the reaction temperature of the ketone-amine condensation reaction is 50~120℃; the ketone-amine condensation reaction is carried out under reflux conditions for 8~16 h.

[0094] After obtaining the compound represented by Formula II, according to the present invention, the compound represented by Formula II is reacted with an iron source, preferably divalent iron halide, such as anhydrous ferric chloride, ferric chloride hexahydrate, FeCl2·DME, or any one or more thereof, in the presence of a solvent to undergo a complexation reaction to obtain the main catalyst. In the present invention, the solvent is selected from any one or more of tetrahydrofuran, toluene, xylene, dichloromethane, or diethyl ether; the molar ratio of the compound represented by Formula II to anhydrous ferric chloride is 1:1 to 1:2, such as 1:1, 1:1.1, 1:1.3, 1:1.5, 1:1.7, or 1:2, etc.

[0095] In some embodiments of the present invention, the compound represented by Formula II is preferably reacted with divalent iron halide in the presence of a solvent at the above-mentioned ratio. The complexation reaction is carried out at room temperature for 12-24 h, such as 12 h, 16 h, 20 h, or 24 h. During the reaction, a dark blue solid gradually precipitates. After filtration, the main catalyst is obtained. Catalyst A is weighed and dissolved in toluene to prepare a main catalyst solution with a concentration of 1-5 μmol / mL, such as 1 μmol / mL, 2 μmol / mL, 3 μmol / mL, 4 μmol / mL, or 5 μmol / mL, for later use.

[0096] In some specific embodiments of the present invention, the catalyst ligand represented by Formula II is selected from any one of Formulas II-1 to II-8:

[0097] Formula II-1;

[0098] Formula II-2;

[0099] Formula II-3;

[0100] Formula II-4;

[0101] Formula II-5;

[0102] Formula II-6;

[0103] Formula II-7;

[0104] Formula II-8.

[0105] In some specific embodiments of the present invention, a method for preparing the main catalyst shown in Formula A is provided, comprising the following steps:

[0106] In a glove box, the ligand compound II synthesized according to the above method is subjected to a complexation reaction with divalent iron halide in a solvent at a molar ratio of 1:1~2. The mixture is stirred at room temperature for 12~24 h, and a solid precipitates from the reaction solution, forming a dark blue suspension. The solution is filtered in the glove box and washed with solvent. The mother liquor is a green solution. An indigo blue solid is filtered out, and the solvent is removed under negative pressure to obtain the main catalyst I, which is catalyst A.

[0107] The solvent is selected from one of tetrahydrofuran, toluene, xylene, dichloromethane, and diethyl ether.

[0108] When using the main catalyst, it is preferred to prepare a 1 μmol / mL main catalyst solution in toluene solvent for later use.

[0109] Following the preparation method of the main catalyst formula I described above, and the complexation method of ligand compound formula II and divalent iron halide, the main catalysts A-1 to A-8 can be prepared using the above methods.

[0110] The present invention also provides a catalyst composition for the preparation of α-olefins by ethylene oligomerization, comprising a main catalyst A, an auxiliary agent B, a co-catalyst C-1, a co-catalyst C-2, and an activator D.

[0111] In this invention, the main catalysts A1 to A8 are the same as those described above.

[0112] In this invention, the auxiliary agent B is selected from perfluoroarylborates and / or perfluoroarylboranes, specifically, it can be selected from any one or more of N,N-dimethylphenylamine tetra(pentafluorophenyl)borate, triphenylcarbatotetrapentafluorophenylborate, 4-isopropyl-4'-methyldiphenyliodonium tetra(pentafluorophenyl)borate, tri(pentafluorophenyl)borane, N,N-bisoctadecylphenylamine tetra(pentafluorophenyl)borate or N,N'-di(hexadecyl)phenylamine tetra(pentafluorophenyl)borate.

[0113] In this invention, the co-catalyst C-1 is selected from alkylaluminum and / or alkylaluminum chloride, specifically, it can be selected from any one or more of trimethylaluminum, triethylaluminum, triisobutylaluminum, tri-n-hexylaluminum, tri-n-octylaluminum, sesquimethylaluminum chloride, diethylaluminum chloride, ethylaluminum dichloride, or ethyl sesquialuminum chloride.

[0114] In this invention, the co-catalyst C-2 is selected from any one or more of alkylaluminum, alkylaluminum chloride, alkylzinc, alkylmagnesium, or alkylmagnesium chloride. Specifically, it can be selected from any one or more of trimethylaluminum, triethylaluminum, triisobutylaluminum, tri-n-hexylaluminum, tri-n-octylaluminum, sesquimethylaluminum chloride, diethylaluminum chloride, ethylaluminum dichloride, ethyl sesquialuminum chloride, diisobutylaluminum chloride, diethylzinc, dimethylmagnesium, diethylmagnesium, or ethylmagnesium chloride.

[0115] The activator D is selected from any one or more of haloalkanes, haloaromatics, or fatty alcohol polyoxyethylene ethers, specifically from chloroform, dichloromethane, 1,2-dichloroethane, tetrachloroethane, and fatty alcohol polyoxyethylene ether RO(CH2CH2O). n H (n=1~5) or any one or more of chlorobenzene.

[0116] In this invention, the main catalyst A, auxiliary agent B, co-catalyst C-1, co-catalyst C-2 and activator D work synergistically to improve the selectivity and activity of the catalyst composition and reduce the content of polymers in the product. Studies have shown that the absence of any one or more of the above five components will have an adverse effect on catalytic activity and selectivity.

[0117] In some embodiments of the present invention, the molar ratio of the main catalyst A to the co-catalyst B in the catalyst composition is 1:(0.1~50), preferably 1:(1~10); the molar ratio of the main catalyst A to the co-catalyst C-1 is 1:(10~1000), preferably 1:(10~800); the molar ratio of the main catalyst A to the co-catalyst C-2 is 1:(10~200), preferably 1:(30~150); and the molar ratio of the main catalyst A to the activator D is 1:(1~100), preferably 1:(10~80).

[0118] The present invention also provides the application of the above-mentioned main catalyst or catalyst composition in the preparation of α-olefins by broad-distribution oligomerization of ethylene.

[0119] The present invention also provides a method for using the above-mentioned catalyst composition for the broad-distribution oligomerization of ethylene to prepare α-olefins, comprising the following steps:

[0120] Under vacuum conditions, a solution of the main catalyst A, auxiliary agent B, co-catalyst C-1, co-catalyst C-2, and activator D are mixed with the reaction solvent according to the specified ratio. The mixture is heated to the reaction temperature, and ethylene is introduced to the reaction pressure to carry out the polymerization reaction, thereby obtaining the broadly distributed oligomer α-olefin.

[0121] In some preferred embodiments of the present invention, under vacuum conditions, a reaction solvent is added to a high-pressure reactor. The reaction solvent is any one or more of n-hexane, cyclohexane, methylcyclohexane, and n-heptane. At the same time, two co-catalysts C-1 and C-2 and activator D are added in the above proportion. Ethylene is introduced to a slightly positive pressure, and the mixture is stirred and heated to the reaction temperature, which is 80~150°C, preferably 90~120°C. Ethylene is used to introduce the 1~5 μmol / mL main catalyst solution and co-agent B obtained in the above steps in the mixing ratio. The ethylene is then pressurized to a reaction pressure of 3~6 MPa, preferably 4~5 MPa, and the polymerization reaction is carried out. The polymerization reaction time is 30~100 min, preferably 50~70 min. After the reaction is quenched, a broadly distributed oligomer product is obtained.

[0122] To further illustrate the present invention, the following embodiments provide a detailed description. The experimental materials used in the following embodiments of the present invention are all commercially available products.

[0123] Preparation Example 1

[0124] Preparation of main catalyst A-1:

[0125] ( Synthesis of precursor-2,6-diacetylpyridine-mono(3,5-dichloroaniline)

[0126] 3.24 g (20 mmol) of 3,5-dichloroaniline, 6.53 g (40 mmol) of 2,6-diacetylpyridine, and 0.2 g of p-toluenesulfonic acid were added to 150 mL of toluene. The reaction mixture was stirred thoroughly to form a homogeneous solution, and heated under reflux for 12 h to allow the reaction to proceed. After TLC showed that the 3,5-dichloroaniline had reacted completely, most of the solvent toluene was removed by rotary evaporation. 200 mL of methanol was added, and the reaction mixture was stirred in a -30 °C cold bath for 12 h. A large amount of yellow solid gradually precipitated. The solid was filtered off and washed with methanol, and then dried under reduced pressure. 1 ¹H-NMR measurements confirmed that the yellow solid was the product of the condensation reaction of 2,6-diacetylpyridine and 3,5-dichloroaniline mono-ketone amine (molecular weight: 307.193), weighing 3.9 g, with a yield of 63.5%.

[0127] ( Synthesis of ligand-bis[2,6-diacetylpyridine-mono(3,5-dichloroaniline)]-2,2'-dichloro-4,4'-diaminobiphenyl (Compound Formula II-1)

[0128] The above steps ( 3.68 g (12 mmol) of 2,6-diacetylpyridine-mono(3,5-dichloroaniline) (molecular weight: 307.193), 0.76 g (3 mmol) of 2,2'-dichloro-4,4'-diaminobiphenyl, and 0.2 g of p-toluenesulfonic acid were added to 100 mL of toluene. The mixture was stirred thoroughly and heated under reflux for 16 h. After TLC showed that 2,2'-dichloro-4,4'-diaminobiphenyl had completely reacted, most of the solvent toluene was removed by rotary evaporation. 200 mL of methanol was added, and the reaction solution was stirred in a -30 °C cold bath for 12 h. A large amount of light yellow solid gradually precipitated. The solid was filtered off, washed with methanol, and then dried under reduced pressure. 1 ¹H-NMR measurements confirmed that the light yellow solid was bis[2,6-diacetylpyridine-mono(3,5-dichloroaniline)]-2,2'-dichloro-4,4'-diaminobiphenyl (compound formula II-1, molecular weight: 542.323), weighing 0.85 g, with a yield of 52.3%.

[0129] NMR characterization analysis of ligand II-1 1HNMR (CDCl3, 400MHz): 8.11~8.32 (m, 6H, pyridine-H); 7.32~7.81 (m, 12H, benze-H); 1.82~1.84 (s, 12H, pyridine-CCH).

[0130] ( Synthesis of complex-main catalyst A-1 (Formula I-1)

[0131] In the glove box, place the above ( 0.81 g (1.5 mmol) of bis[2,6-diacetylpyridine-mono(3,5-dichloroaniline)]-2,2'-dichloro-4,4'-diaminobiphenyl (molecular weight: 542.323) and 0.381 g (3 mmol) of anhydrous ferrous chloride were added to 20 mL of tetrahydrofuran. After stirring at room temperature for 24 h, the mixture was filtered and dried under negative pressure to obtain 0.94 g of dark blue powder, with a yield of 93.7%, which is the main catalyst A-1 of the complex in this preparation example.

[0132] Preparation Example 2

[0133] Preparation of main catalyst A-2:

[0134] ( Synthesis of precursor-2,6-pyridinedicarboxaldehyde-mono(3,5-dichloroaniline)

[0135] 3.24 g (20 mmol) of 3,5-dichloroaniline, 5.40 g (40 mmol) of 2,6-pyridinedicarboxaldehyde, and 0.2 g of p-toluenesulfonic acid were added to 150 mL of toluene. The reaction mixture was stirred thoroughly to form a homogeneous solution, and heated under reflux for 12 h to allow the reaction to proceed. After TLC showed that the 3,5-dichloroaniline had reacted completely, most of the solvent toluene was removed by rotary evaporation. 200 mL of methanol was added, and the reaction mixture was stirred in a -30 °C cold bath for 12 h. A large amount of yellow solid gradually precipitated. The solid was filtered off and washed with methanol, and then dried under reduced pressure. 1 ¹H-NMR measurements confirmed that the yellow solid was the product of the condensation reaction of 2,6-pyridinedicarboxaldehyde and 3,5-dichloroaniline mono-ketamine (molecular weight: 279.14), weighing 4.1 g, with a yield of 73.4%.

[0136] ( Synthesis of ligand-bis[2,6-pyridinedicarboxaldehyde-mono(3,5-dichloroaniline)]-2,2'-dichloro-4,4'-diaminobiphenyl (Compound Formula II-2)

[0137] The above steps ( 3.9 g (14 mmol) of 2,6-pyridinedicarboxaldehyde-mono(3,5-dichloroaniline) (molecular weight: 279.14), 0.89 g (3.5 mmol) of 2,2'-dichloro-4,4'-diaminobiphenyl, and 0.2 g of p-toluenesulfonic acid were added to 100 mL of toluene. The mixture was stirred thoroughly and heated under reflux for 16 h. After TLC showed that 2,2'-dichloro-4,4'-diaminobiphenyl had completely reacted, most of the solvent toluene was removed by rotary evaporation. 200 mL of methanol was added, and the reaction solution was stirred in a -30 °C cold bath for 12 h. A large amount of light yellow solid gradually precipitated. The solid was filtered off and washed with methanol, then dried under reduced pressure. 1 ¹H-NMR measurements confirmed that the light yellow solid was bis[2,6-pyridinedicarboxaldehyde-mono(3,5-dichloroaniline)]-2,2'-dichloro-4,4'-diaminobiphenyl (compound formula II-1, molecular weight: 514.27), weighing 1.18 g, with a yield of 65.4%.

[0138] NMR characterization analysis of ligand II-2 1 HNMR (CDCl3, 400MHz): 8.52~8.81 (m, 4H, pyridine-CH); 8.11~8.23 (m, 6H, pyridine-H); 7.35~7.80 (m, 12H, benze-H).

[0139] ( Synthesis of complex-main catalyst A-1 (Formula I-2)

[0140] In the glove box, place the above ( 1.03 g (2 mmol) of bis[2,6-diacetylpyridine-mono(3,5-dichloroaniline)]-2,2'-dichloro-4,4'-diaminobiphenyl (molecular weight: 514.27) and 0.508 g (4 mmol) of anhydrous ferrous chloride were added to 20 mL of tetrahydrofuran. After stirring at room temperature for 24 h, the mixture was filtered and dried under negative pressure to obtain 1.21 g of dark blue powder, with a yield of 94.8%, which is the main catalyst A-2 of the complex in this preparation example.

[0141] Preparation Example 3

[0142] Repeat the same procedure as in Preparation Example 1, except that 2,6-diacetylpyridine is replaced with 2,6-dibenzoylpyridine to obtain the main catalyst A-3.

[0143] NMR characterization analysis of ligand II-3 1 HNMR (CDCl3, 400MHz): 8.08~8.22 (m, 6H, pyridine-H); 7.35~7.86 (m, 32H, benze-H).

[0144] Preparation Example 4

[0145] Repeat the same procedure as in Preparation Example 1, except that 2,6-diacetylpyridine is replaced with 2,6-bis(2',2'-dimethylpropionyl)pyridine to obtain the main catalyst A-4.

[0146] NMR characterization analysis of ligand II-4 1 HNMR (CDCl3, 400 MHz): 7.95~8.17 (m, 6H, pyridine-H); 7.36~7.81 (m, 12H, benze-H); 0.89~1.06 (s, 36H, pyridine-CCCH).

[0147] Preparation Example 5

[0148] The procedure is essentially the same as in Preparation Example 1, except that 2,6-diacetylpyridine is first reacted with 3,5-dichloroaniline in a ketamine condensation reaction to generate Formula III-5. Then, 2,6-dibenzoylpyridine is reacted with 3,5-dichloroaniline in a ketamine condensation reaction to generate Formula IV-5. Next, Formula III-5 is reacted with 2,2'-dichloro-4,4'-diaminobiphenyl in a ketamine condensation reaction to generate Formula V-5. Formula V-5 is then reacted with Formula IV-5 in a ketamine condensation reaction to obtain ligand II-5. The ligand, after complexation with anhydrous ferrous chloride, yields the main catalyst A-5.

[0149] NMR characterization analysis of ligand II-5 1 HNMR (CDCl3, 400MHz): 7.85~8.19 (m, 6H, pyridine-H); 7.28~7.79 (m, 22H, benze-H); 1.73~1.76 (s, 6H, pyridine-CCH).

[0150] Preparation Example 6

[0151] The procedure is basically the same as that in Example 5, except that 2,6-diacetylpyridine is replaced with 2,6-pyridinedicarboxaldehyde and 2,6-dibenzoylpyridine is replaced with 2,6-bis(2',2'-dimethylpropionyl)pyridine to obtain the main catalyst A-6.

[0152] NMR characterization analysis of ligand II-6 1HNMR (CDCl3, 400MHz): 8.25~8.39 (s, 2H, pyridine-CH; 8.01~8.25 (m, 6H, pyridine-H); 7.26~7.83 (m, 12H, benze-H); 0.88~0.93 (s, 18H, pyridine-CCCH).

[0153] Preparation Example 7

[0154] Repeat the same procedure as in Preparation Example 1, except that 2,2'-dichloro-4,4'-diaminobiphenyl is replaced with 2,2'-dimethyl-4,4'-diaminobiphenyl to obtain the main catalyst A-7.

[0155] NMR characterization analysis of ligand II-7 1 HNMR (CDCl3, 400MHz): 7.92~8.31 (m, 6H, pyridine-H); 7.31~7.79 (m, 12H, benze-H); 2.46~2.62 (s, 6H, benze-CH); 1.79~1.93 (s, 12H, pyridine-CCH).

[0156] Preparation Example 8

[0157] Repeat the same procedure as in Preparation Example 1, except that 2,2'-dichloro-4,4'-diaminobiphenyl is replaced with 2,2'-dibromo-4,4'-diaminobiphenyl to obtain the main catalyst A-8.

[0158] NMR characterization analysis of ligand II-8 1 HNMR (CDCl3, 400MHz): 8.03~8.19 (m, 6H, pyridine-H); 7.21~7.83 (m, 12H, benze-H); 1.75~1.82 (s, 12H, pyridine-CCH).

[0159] Example 1

[0160] The broad-distribution oligomerization of ethylene was carried out in a 500 mL stainless steel high-pressure reactor. First, the reactor was heated to 120℃ and evacuated for 1 hour. After being replaced three times with high-purity N2 and ethylene, 200 mL of cyclohexane was added under vacuum, along with 0.20 mL of triisobutylaluminum (1 mol / L n-hexane solution), 0.12 mL of diethylaluminum chloride solution (diluted to 250 μmol / mL in cyclohexane), and 0.5 mL of dichloromethane dilution (diluted to 50 μmol / mL in cyclohexane). Ethylene was introduced to a slightly positive pressure, and the reactor was stirred. The pressure of the high-pressure reactor was gradually adjusted to the reaction temperature of 80℃. 0.5 mL of 1 μmol / mL main catalyst A-1 solution and 0.25 mL of N,N-dimethylphenylammonium tetra(pentafluorophenyl)borate (2 μmol / mL toluene solution) were added. The pressure was increased to 4 MPa with ethylene to start the reaction. The temperature was controlled, and the polymerization reaction time was 60 min. After the reaction was completed, the reactor was quenched, cooled, and depressurized. The reactor was then disassembled to obtain a broadly distributed oligomer of ethylene. Liquid products were quantitatively analyzed using gas chromatography with an internal standard, n-heptane as the internal standard. Solid products were dried and weighed. Experimental data were calculated using the following method, detailed in Table 1 below. Broadly distributed oligomer composition: C4: 20%, C6+C8: 35%, C... 10 +C 12 21%, C 14 ~C 20 17%, C 22 ~C 28 7%.

[0161] Polymer content (wt%) = mass of solid polymer product (g) / [mass of liquid product (g) + mass of solid polymer product (g)];

[0162] Catalyst activity (kg / (gFe·h)) = Total product mass (kg) / [Iron mass (g) × Reaction time (h)];

[0163] The selectivity of α-olefins can be calculated by gas chromatography analysis to obtain the mass ratio of α-olefins with different carbon numbers and their corresponding non-α-olefins.

[0164] Example 2

[0165] The broad-distribution oligomerization of ethylene was carried out in a 500 mL stainless steel high-pressure reactor. First, the reactor was heated to 120℃ and evacuated for 1 hour. After being replaced three times with high-purity N2 and ethylene, 200 mL of cyclohexane was added under vacuum, along with 0.25 mL of triisobutylaluminum (1 mol / L n-hexane solution), 0.16 mL of diethylaluminum chloride solution (diluted to 250 μmol / mL in cyclohexane), and 0.5 mL of dichloromethane dilution (diluted to 50 μmol / mL in cyclohexane). Ethylene was introduced to a slightly positive pressure, and the reactor was stirred. The pressure of the high-pressure reactor was gradually adjusted to the reaction temperature of 80℃. 0.5 mL of 1 μmol / mL main catalyst A-1 solution and 0.5 mL of N,N-dimethylphenylammonium tetra(pentafluorophenyl)borate (2 μmol / mL toluene solution) were added. The pressure was increased to 4 MPa with ethylene to start the reaction. The temperature was controlled, and the polymerization reaction time was 60 min. After the reaction was completed, the reactor was quenched, cooled, and depressurized. The reactor was then disassembled to obtain a broadly distributed oligomer of ethylene. Liquid products were quantitatively analyzed using gas chromatography with an internal standard, using n-heptane as the internal standard. Solid products were dried and weighed. Experimental data were calculated according to the method in Example 1, and are summarized in Table 1 below. Broadly distributed oligomer composition: C4: 21%, C6+C8: 37%, C... 10 +C 12 20%, C 14 ~C 20 15%, C 22 ~C 28 7%.

[0166] Example 3

[0167] The broad-distribution oligomerization of ethylene was carried out in a 500 mL stainless steel high-pressure reactor. First, the reactor was heated to 120℃ and evacuated for 1 hour. After being replaced three times with high-purity N2 and ethylene, 200 mL of cyclohexane was added under vacuum, along with 0.4 mL of triisobutylaluminum (1 mol / L n-hexane solution), 0.2 mL of ethyl sesquialuminum chloride (diluted to 250 μmol / mL in cyclohexane), and 0.5 mL of dichloromethane dilution (diluted to 50 μmol / mL in cyclohexane). Ethylene was introduced to a slightly positive pressure, and the reactor was stirred. The pressure of the high-pressure reactor was gradually adjusted to the reaction temperature of 80℃. 0.5 mL of 1 μmol / mL main catalyst A-2 solution and 0.5 mL of N,N-dimethylphenylammonium tetra(pentafluorophenyl)borate (2 μmol / mL toluene solution) were added. The pressure was increased to 4 MPa with ethylene to start the reaction. The temperature was controlled, and the polymerization reaction time was 60 min. After the reaction was completed, the reactor was quenched, cooled, and depressurized. The reactor was then disassembled to obtain a broadly distributed oligomer of ethylene. Liquid products were quantitatively analyzed using gas chromatography with an internal standard, using n-heptane as the internal standard. Solid products were dried and weighed. Experimental data were calculated according to the method in Example 1, and are summarized in Table 1 below. Broadly distributed oligomer composition: C4: 19%, C6+C8: 36%, C... 10 +C 12 21%, C 14 ~C 20 17%, C 22 ~C 28 7%.

[0168] Example 4

[0169] The broad-distribution oligomerization of ethylene was carried out in a 500 mL stainless steel high-pressure reactor. First, the reactor was heated to 120 °C and evacuated for 1 hour. Then, after three replacements with high-purity N2 and ethylene, 200 mL of cyclohexane was added under vacuum, followed by 0.25 mL of triethylaluminum (1 mol / L n-hexane solution), 0.16 mL of diethylaluminum chloride solution (diluted to 250 μmol / mL in cyclohexane), and 0.5 mL of dichloromethane dilution (diluted to 50 μmol / mL in cyclohexane). Ethylene was introduced to a slightly positive pressure, and the reactor was stirred. The temperature of the high-pressure reactor was gradually adjusted to the reaction temperature of 90 °C. 0.5 mL of a 1 μmol / mL solution of the main catalyst A-2 and 0.5 mL of triphenylcarbatetrafluorophenyl borate (2 μmol / mL toluene solution) were added. The pressure was increased to 5 MPa with ethylene to initiate the reaction. The temperature was controlled, and the polymerization time was 60 min. After the reaction, the reactor was quenched, cooled, and depressurized. The reactor was then disassembled to obtain the broad-distribution oligomer of ethylene. Liquid products were quantitatively analyzed using gas chromatography with an internal standard, using n-heptane as the internal standard. Solid products were dried and weighed. Experimental data were calculated according to the method in Example 1, and are summarized in Table 1 below. Broadly distributed oligomer composition: C4: 22%, C6+C8: 37%, C... 10 +C 12 20%, C 14 ~C 20 16%, C 22 ~C 28 5%.

[0170] Example 5

[0171] The broad-distribution oligomerization of ethylene was carried out in a 500 mL stainless steel high-pressure reactor. First, the reactor was heated to 120°C and evacuated for 1 hour. After being replaced three times with high-purity N2 and ethylene, 200 mL of cyclohexane was added under vacuum, along with 0.3 mL of triethylaluminum (1 mol / L n-hexane solution), 0.16 mL of ethyl sesquialuminum chloride solution (diluted to 250 μmol / mL in cyclohexane), and 0.5 mL of chlorobenzene dilution (diluted to 50 μmol / mL in cyclohexane). Ethylene was introduced to a slightly positive pressure, and the reactor was stirred. The pressure of the high-pressure reactor was gradually adjusted to the reaction temperature of 120°C. 0.5 mL of 1 μmol / mL main catalyst A-2 solution and 0.5 mL of N,N-dimethylphenylammonium tetra(pentafluorophenyl)borate (2 μmol / mL toluene solution) were added. The pressure was increased to 6 MPa with ethylene to start the reaction. The temperature was controlled, and the polymerization reaction time was 60 min. After the reaction was completed, the reactor was quenched, cooled, and depressurized. The reactor was then disassembled to obtain a broadly distributed oligomer of ethylene. Liquid products were quantitatively analyzed using gas chromatography with an internal standard, using n-heptane as the internal standard. Solid products were dried and weighed. Experimental data were calculated according to the method in Example 1, and are summarized in Table 1 below. Broadly distributed oligomer composition: C4: 25%, C6+C8: 38%, C... 10 +C 12 18%, C 14 ~C 20 15%, C 22 ~C 28 4%.

[0172] Example 6

[0173] The broad-distribution oligomerization of ethylene was carried out in a 500 mL stainless steel high-pressure reactor. First, the reactor was heated to 120℃ and evacuated for 1 hour. After being replaced three times with high-purity N2 and ethylene, 200 mL of cyclohexane was added under vacuum, along with 0.20 mL of triethylaluminum (1 mol / L n-hexane solution), 0.12 mL of diethylaluminum chloride solution (diluted to 250 μmol / mL in cyclohexane), and 0.5 mL of dichloromethane dilution (diluted to 50 μmol / mL in cyclohexane). Ethylene was introduced to a slightly positive pressure, and the reactor was stirred. The pressure of the high-pressure reactor was gradually adjusted to the reaction temperature of 80℃. 0.5 mL of 1 μmol / mL main catalyst A-3 solution and 0.25 mL of N,N-dimethylphenylammonium tetra(pentafluorophenyl)borate (2 μmol / mL toluene solution) were added. The pressure was increased to 4 MPa with ethylene to start the reaction. The temperature was controlled, and the polymerization reaction time was 60 min. After the reaction was completed, the reactor was quenched, cooled, and depressurized. The reactor was then disassembled to obtain a broadly distributed oligomer of ethylene. Liquid products were quantitatively analyzed using gas chromatography with an internal standard, n-heptane as the internal standard. Solid products were dried and weighed. Experimental data were calculated using the following method, detailed in Table 1 below. Broadly distributed oligomer composition: C4: 31%, C6+C8: 28%, C... 10 +C 12 20%, C 14 ~C 20 16%, C 22 ~C 28 5%.

[0174] Comparative Example 1

[0175] No activator D was added during the broad-distribution oligomerization reaction of ethylene, and other conditions were the same as in Example 2. The experimental data are summarized in Table 1 below. Composition distribution of the broad-distribution oligomerization products: C4: 23%, C6+C8: 35%, C 10 +C 12 21%, C 14 ~C 20 16%, C 22 ~C 28 5%.

[0176] Comparative Example 2

[0177] In the broad-distribution oligomerization reaction of ethylene, no co-catalyst C-2 and activator D were added, and other conditions were the same as in Example 2. The experimental data are summarized in Table 1 below. Composition distribution of the broad-distribution oligomerization product: C4: 20%, C6+C8: 33%, C 10 +C 12 20%, C 14 ~C 20 18%, C 22 ~C 28 9%.

[0178] The characterization of the catalyst systems, reaction parameters, and products of Examples 1-6 and Comparative Examples 1-2 is shown in Table 1 below:

[0179] Table 1

[0180]

[0181] As shown in Table 1, comparing Examples 1-3, when the molar ratio of additive B to catalyst A is 2, the catalyst exhibits high activity and comparable selectivity. Adding too much or too little additive will slightly reduce the catalyst activity. Comparing Examples 4-6, catalysts A2 and A3 also demonstrate good performance. Combining Comparative Example 1 (lacking activator D) and Comparative Example 2 (lacking additive C-2 and activator D), it is evident that catalyst systems composed of quaternary and ternary components show significantly reduced catalyst activity and the generation of large amounts of polymers, easily causing blockage in the equipment pipelines and affecting the long-term stable operation of the catalyst. Therefore, precise proportioning and synergistic effects of the pentagonal catalyst system are crucial for achieving high activity, high selectivity, and low polymer formation in this system.

[0182] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A procatalyst for the production of alpha-olefins by ethylene oligomerization with a broad distribution, characterized in that, having the structure of Formula I: Formula I; wherein R1, R2are each independently selected from hydrogen, substituted or unsubstituted C1-C6 alkyl or substituted or unsubstituted C6-C15 aryl; R3is selected from halogen, C1-C3 alkane or C1-C3 haloalkyl.

2. The procatalyst of claim 1, wherein said R1, R2are each independently selected from one or more of hydrogen, methyl, ethyl, isopropyl or phenyl; said R3is selected from one or more of F, Cl, Br, methyl, ethyl, trifluoromethyl.

3. The procatalyst according to claim 1 or 2, characterized in that, said procatalyst is selected from any one of the following Formula A-1 to Formula A-8: Formula A-1; Formula A-2; Formula A-3; Formula A-4; Formula A-5; Formula A-6; Formula A-7; Formula A-8.

4. A process for the preparation of a procatalyst as claimed in any one of claims 1 to 3, characterised in that, comprising the following steps: S1: providing a compound shown in Formula II; S2: subjecting the compound shown in Formula II to a complexation reaction with an iron source in the presence of a solvent to obtain a procatalyst; Formula II.

5. The preparation method according to claim 4, characterized in that, said iron source is selected from divalent iron halide; said divalent iron halide is selected from any one or more of anhydrous iron dichloride, iron chloride hexahydrate or FeCl2.DME; said solvent is selected from any one or more of tetrahydrofuran, toluene, xylene, dichloromethane or diethyl ether; said compound shown in Formula II and the iron source are in a molar ratio of 1:1 to 1:1.2; said complexation reaction is at room temperature for 12 to 24 hours.

6. The production method according to claim 4 or 5, characterized by, said compound shown in Formula II is prepared according to the following method: ) subjecting each of the same or different bisacylpyridines to a ketone-amine condensation reaction with 3,5-dichloroaniline in the presence of a catalyst in a solvent to produce Formula III and Formula IV;​ Formula III; Formula IV; ) continuing the keto-amine condensation reaction of the compound represented by Formula III obtained in step ( ) with the substituted biphenyl diamine in the presence of a catalyst in a solvent to obtain Formula V;​ Formula V; ) The compound of formula II is obtained by continuing the keto-amine condensation reaction of the compound of formula V obtained in step ( ) with the compound of formula IV obtained in step ( ) in the presence of a catalyst in a solvent.​ 7. The production method according to claim 6, characterized by, Step ( ) the solvent is selected from any one or more of methanol, ethanol, acetic acid, toluene or dichloromethane; the catalyst is selected from any one or more of formic acid, acetic acid, hydrochloric acid, p-toluenesulfonic acid or zinc chloride; said 3,5-dichloroaniline and the bipyridyl are in a molar ratio of 1:2 to 3; said compound shown in Formula III and the substituted biphenyldiamine are in a molar ratio of 1:2 to 4; said compound shown in Formula V and the compound shown in Formula IV are in a molar ratio of 1:2 to 3; said ketone amine condensation reaction is at a temperature of 50 to 120℃; said ketone amine condensation reaction is carried out under reflux conditions for 8 to 16 hours.

8. A catalyst composition for the oligomerization of ethylene to α-olefins, characterized in that, comprising a procatalyst A, a co-catalyst B, a co-catalyst C-1, a co-catalyst C-2 and an activator D; said procatalyst A is the procatalyst as claimed in any one of claims 1 to 3 or prepared according to the preparation method as claimed in any one of claims 4 to 7; said co-catalyst B is selected from perfluoroaryl borate and / or perfluoroaryl borane; said co-catalyst C-1 is selected from alkyl aluminum and / or chlorinated alkyl aluminum; said co-catalyst C-2 is selected from any one or more of alkyl aluminum, chlorinated alkyl aluminum, alkyl zinc, alkyl magnesium or chlorinated alkyl magnesium; said activator D is selected from any one or more of haloalkane, haloarene or fatty alcohol polyoxyethylene ether; said procatalyst A, co-catalyst B, co-catalyst C-1, co-catalyst C-2 and activator D are in a molar ratio of 1:(0.1-50):(10-1000):(10-200):(1-100).

9. Use of the procatalyst as claimed in any one of claims 1 to 3, the procatalyst prepared according to the preparation method as claimed in any one of claims 4 to 7 or the catalyst composition as claimed in claim 8 in the preparation of α-olefins by ethylene broad distribution oligomerization.

10. A process for the preparation of α-olefins by ethylene oligomerization using the catalyst composition of claim 8, characterized in that, comprising the following steps: The solution of the main catalyst A, the auxiliary B, the auxiliary catalyst C-1, the auxiliary catalyst C-2 and the activator D are mixed according to the ratio and the reaction solvent under vacuum condition, heated to the reaction temperature, ethylene is introduced to the reaction pressure, and the polymerization reaction is carried out to obtain a wide distribution oligomerization product alpha-olefin; The temperature of the reaction is 80-150 DEG C; The pressure of the reaction is 3-6 MPa; The time of the polymerization reaction is 30-100 min.

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