Catalyst for preparing polyethylene wax as well as preparation method and application of catalyst

Abstract

The invention provides a catalyst for preparing polyethylene wax as well as a preparation method and application of the catalyst. The structure of the catalyst is shown as a formula I. In the formula I, R1 is selected from hydrogen, n-alkyl, adamantyl or tertiary butyl; r2 is selected from hydrogen, normal alkyl, adamantyl or tertiary butyl; n-alkyl comprises methyl, ethyl, n-propyl, n-butyl, n-amyl or n-hexyl; m is selected from Ti or Zr. The problem that a catalyst for catalyzing a polyethylene wax reaction in the prior art is too high in cost can be solved, and the catalyst is suitable for the field of polyolefin catalysts.

Description

Technical Field

[0001] The present invention relates to the field of polyolefin catalysis, and in particular to a catalyst for preparing polyethylene wax, a preparation method thereof and an application thereof. Background Art

[0002] Low molecular weight polyethylene (LMWPE) is a waxy polyolefin resin commonly known as polyethylene wax. Its molecular weight generally ranges from 1,000 to 10,000 g / mol, with a relatively concentrated molecular weight distribution of approximately 1 to 5. Its crystallinity is 50 to 80%. Its melting point varies depending on its average molecular weight, typically between 90°C and 120°C. Its melt viscosity is low, with melt viscosity and hardness close to those of paraffin wax. In practical applications, LMWPE is primarily used as a replacement for traditional paraffin wax. Its excellent compatibility with other polyolefin resins has led to its widespread use in the chemical industry.

[0003] In the prior art, metallocene catalysts are commonly used to catalyze the polymerization of ethylene in the production of polyethylene wax. Although traditional metallocene catalysts have demonstrated high activity in polymerization reactions, their preparation methods are relatively complex, the raw materials and preparation costs are high, and they are sensitive to water and oxygen, making them difficult to store. With the growing demand for the polyethylene wax synthesis industry, the demand for catalysts continues to increase. Therefore, using traditional metallocene catalysts to synthesize large quantities of polyethylene wax would result in excessively high industrial production costs. Therefore, developing a catalyst that is low-cost and easy to synthesize would be beneficial to the development of the polyethylene wax industry. Summary of the Invention

[0004] The main purpose of the present invention is to provide a catalyst for preparing polyethylene wax and its preparation method and application, so as to solve the problem of high cost of catalysts used in the prior art for catalyzing polyethylene wax reactions.

[0005] In order to achieve the above object, according to a first aspect of the present invention, a catalyst for preparing polyethylene wax is provided, the structure of the catalyst is shown in the following formula I:

[0006]

[0007] Formula I; wherein R1 is selected from hydrogen, n-alkyl, adamantyl or tert-butyl; R2 is selected from hydrogen, n-alkyl, adamantyl or tert-butyl; n-alkyl includes methyl, ethyl, n-propyl, n-butyl, n-pentyl or n-hexyl; M is selected from Ti or Zr.

[0008] Further, the catalyst comprises:

[0009] According to a second aspect of the present invention, a method for preparing a catalyst for preparing polyethylene wax is provided. The structural formula of the catalyst is shown in Formula I. The preparation method comprises: mixing and stirring a first compound and a second compound under a first atmosphere to obtain a catalyst; the first compound comprises tetraisopropyl titanate and / or tetraisopropyl zirconate; and the structural formula of the second compound is shown in Formula II:

[0010]

[0011] Among them, R3 is selected from hydrogen, n-alkyl, adamantyl or tert-butyl; R4 is selected from hydrogen, n-alkyl, adamantyl or tert-butyl; R5 is selected from hydrogen, n-alkyl, adamantyl or tert-butyl; R6 is selected from hydrogen, n-alkyl, adamantyl or tert-butyl; n-alkyl includes methyl, ethyl, n-propyl, n-butyl, n-pentyl or n-hexyl.

[0012] Furthermore, the preparation method of the second compound includes: a) mixing the third compound, the fourth compound, and the Lewis acid in a solvent under a first atmosphere and conducting a first reaction to obtain a first reaction system; b) adjusting the pH of the first reaction system to 5-6, and then purifying the first reaction system to obtain the second compound; wherein the third compound includes an adamantane compound or a tert-butyl compound; the fourth compound includes biphenol; preferably, the adamantane compound includes one or more of adamantane alcohol, chloroadamantane, bromoadamantane or iodoadamantane; preferably, the tert-butyl compound includes one or more of tert-butyl chloride, tert-butyl bromide or tert-butyl iodide.

[0013] Furthermore, the temperature of the first reaction is 20 to 50° C., and the time of the first reaction is 1 to 10 hours; preferably, the solvent includes one or more of dichloromethane, carbon disulfide, carbon tetrachloride or nitrobenzene; preferably, the Lewis acid includes one of concentrated sulfuric acid, AlCl 3 , FeCl 3 , BBr 3 or BCl 3 .

[0014] Further, the first atmosphere includes nitrogen and / or an inert gas; preferably, the inert gas includes argon and / or helium.

[0015] Furthermore, the preparation method includes: S1) under a first atmosphere, mixing the first compound and the second compound at -75 to -60°C to obtain a first mixed system, stirring until the temperature of the first mixed system rises to 15 to 30°C to obtain a second mixed system; S2) heating the second mixed system to 50 to 80°C, performing a second reaction, and obtaining the catalyst; preferably, the time of the second reaction is 10-24 hours.

[0016] According to a third aspect of the present invention, a catalyst composition for preparing polyethylene wax is provided, which comprises a first catalyst and a second catalyst; the first catalyst comprises the above-mentioned catalyst for preparing polyethylene wax, or a catalyst prepared using the above-mentioned method for preparing the catalyst for preparing polyethylene wax; and the second catalyst comprises an alkyl aluminum.

[0017] Furthermore, the molar ratio of the first catalyst to the second catalyst is 1:100-6000.

[0018] According to a fourth aspect of the present invention, a method for preparing polyethylene wax is provided, which comprises: using the above-mentioned catalyst for preparing polyethylene wax, or the catalyst obtained by the above-mentioned method for preparing the catalyst for preparing polyethylene wax, or the above-mentioned catalyst composition for preparing polyethylene wax as a catalyst to catalyze the polymerization reaction of ethylene to synthesize polyethylene wax.

[0019] By applying the technical solution of the present invention, polyethylene wax can be successfully synthesized using the compound of the structural formula I as a catalyst for preparing polyethylene wax. The catalyst preparation cost of the present application is low, which reduces the overall cost of industrial polyethylene wax synthesis and is more conducive to the industrial development of polyethylene wax synthesis. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The accompanying drawings, which constitute part of this application, are intended to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are intended to explain the present invention and do not constitute an undue limitation of the present invention. In the accompanying drawings:

[0021] Figure 1 The hydrogen nuclear magnetic resonance spectrum of the catalyst C1 in Example 1 of the present invention is shown.

[0022] Figure 2 The carbon nuclear magnetic resonance spectrum of catalyst C2 in Example 2 of the present invention is shown.

[0023] Figure 3 The high-resolution mass spectrum of catalyst C2 in Example 2 of the present invention is shown.

[0024] Figure 4 The DSC spectrum of the polyethylene wax polymer obtained in Example 8 of the present invention is shown.

[0025] Figure 5 The GPC spectrum of the polyethylene wax polymer obtained in Example 8 of the present invention is shown.

[0026] Figure 6 The DSC spectrum of the polyethylene wax polymer obtained in Example 12 of the present invention is shown.

[0027] Figure 7The GPC spectrum of the polyethylene wax polymer obtained in Example 12 of the present invention is shown. DETAILED DESCRIPTION

[0028] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present invention will be described in detail below with reference to the embodiments.

[0029] As mentioned in the background, metallocene catalysts are commonly used in the preparation of polyethylene wax in the prior art. However, the synthesis of conventional metallocene catalysts is complex, which in turn increases the cost of preparing such catalysts, further increasing the cost of preparing polyethylene wax. Excessively high preparation costs are detrimental to the industrialization of polyethylene wax. Therefore, in this application, the inventors have attempted to develop a new catalyst for preparing polyethylene wax that has a simple preparation process and low cost, can replace metallocene catalysts, and successfully catalyzes the synthesis of polyethylene wax. Based on this, a series of protection schemes are proposed in this application.

[0030] In a first typical embodiment of the present application, a catalyst for preparing polyethylene wax is provided, and the structure of the catalyst is shown in the following formula I:

[0031]

[0032] Wherein, R1 is selected from hydrogen, n-alkyl, adamantyl or tert-butyl; R2 is selected from hydrogen, n-alkyl, adamantyl or tert-butyl; n-alkyl includes methyl, ethyl, n-propyl, n-butyl, n-pentyl or n-hexyl; M is selected from Ti or Zr.

[0033] In the prior art, when synthesizing polyethylene wax, metallocene catalysts with high catalytic activity are usually selected due to the special chemical properties and molecular distribution of polyethylene wax. However, the preparation method of metallocene catalysts is complicated, which leads to an increase in the preparation cost of such catalysts, further increasing the cost of synthesizing polyethylene wax.

[0034] The catalyst of the present application utilizes Ti or Zr as the metal element of the catalytic center and introduces a large steric hindered group on biphenol to obtain a new catalyst that can be used in the synthesis of polyethylene wax. Compared with metallocenes, the preparation cost is lower, the water and oxygen sensitivity is also low, and it is easier to store. It can successfully catalyze the synthesis of polyethylene wax. When used in the synthesis of polyethylene wax, the catalyst of the present application has the same effect as the synthesis reaction involving metallocene catalysts in the prior art, but the cost is lower, further reducing the cost of polyethylene wax synthesis, and is more suitable for application in the industrialization of polyethylene wax.

[0035] In a preferred embodiment, the catalyst comprises:

[0036] In addition to high preparation costs, metallocene catalysts are also overly sensitive to water and oxygen, making them difficult to store. The gold catalysts in this application, on the other hand, are less sensitive to water and oxygen, less susceptible to deactivation, and easier to store. Furthermore, by adjusting the type of sterically hindered substituents on the biphenyl ring of this catalyst, the steric and electronic effects of the metal center can be controlled, thereby regulating the molecular weight and molecular weight distribution of the polyethylene polymer. This allows for the production of highly linear, low-molecular-weight polyethylene waxes with a narrow molecular weight distribution, controllable molecular weight, and high crystallinity.

[0037] "Ad" is the abbreviation of "Adamany", which means adamantyl. t "Bu" refers to "di(tert-butyl)", i.e. tert-butyl.

[0038] In a second typical embodiment of the present application, a method for preparing a catalyst for preparing polyethylene wax is provided, the method comprising: mixing and stirring a first compound and a second compound under a first atmosphere to obtain a catalyst; the first compound comprises tetraisopropyl titanate (Ti(O i Pr)4) and / or tetraisopropyl zirconate (Zr(O i Pr) 4) Preferably, the compound is a toluene solution of tetraisopropyl titanate and / or a toluene solution of tetraisopropyl zirconate.

[0039] The structural formula of the second compound is shown in Formula II:

[0040]

[0041] Among them, R3 is selected from hydrogen, n-alkyl, adamantyl or tert-butyl; R4 is selected from hydrogen, n-alkyl, adamantyl or tert-butyl; R5 is selected from hydrogen, n-alkyl, adamantyl or tert-butyl; R6 is selected from hydrogen, n-alkyl, adamantyl or tert-butyl; n-alkyl includes methyl, ethyl, n-propyl, n-butyl, n-pentyl or n-hexyl.

[0042] In a preferred embodiment, the preparation method of the second compound includes: a) mixing the third compound, the fourth compound, and the Lewis acid in a solvent under a first atmosphere and conducting a first reaction to obtain a first reaction system; b) adjusting the pH of the first reaction system to 5-6, and then purifying the first reaction system to obtain the second compound; the third compound includes an adamantane compound or a tert-butyl compound; the fourth compound includes biphenol; preferably, the adamantane compound includes one or more of adamantane alcohol, chloroadamantane, bromoadamantane or iodoadamantane; preferably, the tert-butyl compound includes one or more of tert-butyl chloride, tert-butyl bromide or tert-butyl iodide.

[0043] The present application utilizes the reaction of biphenol with Lewis acid to introduce a large sterically hindered substituent on the biphenyl ring. By adjusting the substituent type on the biphenyl ring of the catalyst of the present application, the activity of the single-site catalyst is retained, the spatial and electronic effects of the metal center are controlled, and the molecular weight and molecular weight distribution of the polyethylene polymer are regulated. In addition, the catalyst is less sensitive to water and oxygen and is easier to preserve than metallocene catalysts. The route for preparing the catalyst of the present application is short and the steps are simple. It is easy to separate and purify in the subsequent ethylene polymerization reaction for preparing polyethylene wax. The industrial cost is low, which is beneficial to the overall cost of polyethylene wax synthesis and promotes the industrial development of polyethylene wax synthesis.

[0044] In a preferred embodiment, the temperature of the first reaction is 20-50°C, including but not limited to 20°C, 21°C, 22°C, 23°C, 24°C, 25°C, 26°C, 27°C, 28°C, 29°C, 30°C, 31°C, 32°C, 33°C, 34°C, 35°C, 36°C, 37°C, 38°C, 39°C, 40°C, 41°C, 42°C, 43°C, 44°C, 45°C, 46°C, 47°C, 48°C, 49°C or 50°C, and the time of the first reaction is 1-10 hours, including but not limited to 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10 hours; preferably, the solvent comprises one or more of dichloromethane, carbon disulfide, carbon tetrachloride or nitrobenzene; preferably, the Lewis acid comprises one of concentrated sulfuric acid, AlCl3, FeCl3, BBr3 or BCl3.

[0045] In a preferred embodiment, the first atmosphere comprises an inert gas; preferably, the inert gas comprises one or more of argon, nitrogen or helium.

[0046] In a preferred embodiment, S1) under a first atmosphere, the first compound and the second compound are first mixed at -75 to -60°C (including but not limited to -75°C, -70°C, -65°C or -60°C) to obtain a first mixed system, and stirred until the temperature of the first mixed system rises to 15 to 30°C (including but not limited to 15°C, 16°C, 17°C, 18°C, 19°C, 20°C, 21°C, 22°C, 23°C, 24°C, 25°C, 26°C, ℃, 27℃, 28℃, 29℃ or 30℃) to obtain a second mixed system; S2) heating the second mixed system to 50-80℃ (including but not limited to 50℃, 60℃, 70℃ or 80℃) to carry out a second reaction to obtain the catalyst; preferably, the time of the second reaction is 10-24h, including but not limited to 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23 or 24h.

[0047] In a specific embodiment of the present application, the preparation method of the above-mentioned catalyst comprises: under the protection of an inert atmosphere, using a Lewis acid as a catalyst, adding a third compound, a fourth compound and a solvent to a reactor, reacting at a temperature of 0 to 90° C. for 1 to 10 hours, adjusting the pH to weakly acidic with a 1M NaOH solution at 0° C., allowing the layers to stand, extracting the aqueous layer with dichloromethane, combining the organic phases, washing with a saturated NaCl aqueous solution until neutral, drying with anhydrous NaSO4, filtering, removing the solvent under reduced pressure, and performing silica gel column chromatography with petroleum ether and ethyl acetate as eluents to obtain white needle-shaped crystals, i.e., the above-mentioned second compound;

[0048] The second compound was prepared into a toluene solution, and M(O i A toluene solution of Pr)4 (first compound) (first mixed system) is slowly restored to room temperature (second mixed system), reacted at 50-80°C for 10-24h (second reaction), and the solvent is removed in vacuo. The obtained solid is washed three times with n-hexane, the supernatants are combined, and placed in a refrigerator for recrystallization to obtain the catalyst of the present application.

[0049] By controlling the temperature, time and pH range of the catalyst prepared in the present application, a catalyst with high activity and good thermal stability can be prepared, which is beneficial to the synthesis reaction of polyethylene wax in which it participates.

[0050] In a second typical embodiment of the present application, a catalytic composition for preparing polyethylene wax is provided, the catalytic composition comprising a first catalyst and a second catalyst;

[0051] The first catalyst comprises the above-mentioned catalyst for preparing polyethylene wax, or a catalyst prepared by the above-mentioned method for preparing the catalyst for preparing polyethylene wax, or a catalyst prepared by the above-mentioned method for preparing the catalyst for preparing polyethylene wax; the second catalyst comprises an aluminum alkyl. Preferably, the aluminum alkyl comprises ethylaluminum sesquichloride.

[0052] The catalyst of the present application has a large steric hindrance substituent group with multiple substitutions and a single catalytic active center, and can achieve regulation of polymer molecular weight by changing its substituent group, structure and polymerization reaction conditions. In the polymerization reaction of synthetic polyethylene wax, the traditional co-catalyst that participates in the reaction together with the metallocene catalyst is MAO and MMAO-based catalysts, which also have the disadvantages of difficulty in synthesis and high cost. When the above-mentioned catalyst of the present application is used as the main catalyst for synthetic polyethylene wax, the secondary catalyst can be replaced by the low-priced alkyl aluminum sesquiethylaluminum chloride instead of the traditional high-cost MAO and MMAO co-catalyst. When the catalyst of the present application and sesquiethylaluminum chloride are used in the synthetic reaction of polyethylene wax, the catalytic activity is high and the performance is more stable, and polyethylene wax with a small molecular weight and narrow distribution can be successfully synthesized.

[0053] In a preferred embodiment, the molar ratio of the first catalyst to the second catalyst is 1:100-6000.

[0054] In a fourth typical embodiment of the present application, a method for preparing polyethylene wax is provided, which comprises: using the above-mentioned catalyst for preparing polyethylene wax as a catalyst, or a catalyst prepared by the above-mentioned method for preparing the catalyst for preparing polyethylene wax, or using the above-mentioned catalytic composition for preparing polyethylene wax to catalyze the polymerization reaction of ethylene to synthesize polyethylene wax.

[0055] When the catalyst of the present application is used to catalyze the reaction of preparing polyethylene wax, the synthesis method includes: adding a toluene solution (1 to 5 mL) of the catalyst of the present application and the above-mentioned co-catalyst at an ethylene pressure of 1.0 to 3.0 MPa, using toluene or chlorobenzene as a solvent, and reacting at a reaction temperature of 0 to 170°C for 15 to 60 minutes to prepare polyethylene wax.

[0056] When used in the catalytic synthesis of polyethylene wax, the catalyst of the present application has high reaction activity and good thermal stability, exhibits strong control performance on the molecular weight of polyethylene wax, and can prepare highly linear low molecular weight polyethylene wax.

[0057] In a preferred embodiment, the molecular weight of the polyethylene wax is 1.00×10 3 ~8.00×10 3 g / mol, preferably, the polymerization activity of the ethylene polymerization reaction occurring during the synthesis of polyethylene wax exceeds 1.00×10 6 g / molCat / h.

[0058] In the specific embodiment of the present application, under the conditions of 100°C and 30 min, the activity of the catalyst of the present application in catalyzing ethylene polymerization can be as high as 2.910×10 6 g / (mol·Ti·h), 2.164×10 6 g / (mol·Zr·h), and even at a relatively high temperature of 120°C, the reaction activity of the catalyst of the present application can still reach 0.664×10 6 g / (mol·Ti·h), 1.539×10 6 g / (mol·Zr·h), which proves that the catalyst of the present application has good thermal stability, can adapt to the operating temperature of industrial production, and has broad industrial application prospects.

[0059] The beneficial effects of the present application will be further explained in detail below with reference to specific embodiments.

[0060] Unless otherwise specified, all reagents used in the examples of this application are conventional commercially available products.

[0061] Example 1

[0062] The steps of the preparation method for preparing the catalyst for preparing polyethylene wax in this embodiment are as follows:

[0063] The structural formula of the catalyst is shown in C1.

[0064] The synthetic route is as follows:

[0065]

[0066] Synthesis of L1: Add 2,2'-biphenol (10 mmol, 1.86 g) and adamantane alcohol (25 mmol, 3.80 g) to a 100 mL Schlenk flask, then take 50 mL of dichloromethane. Slowly add concentrated sulfuric acid (10 mmol, 0.5 mL) dropwise at 0°C and continue the reaction for 48 h.

[0067] Adjust the pH to 5-6 with 1 mol / L NaOH solution, extract with dichloromethane (10 mL x 3), combine the organic phases, dry over anhydrous Na₂SO₄, and remove the solvent under reduced pressure. Column chromatography (PE:EA = 30:1) afforded a white solid in a 54% yield. Comparison with a standard H₄ spectrum confirmed the title compound.

[0068] 1 H NMR (400MHz, CDCl3) δ7.22 (dd, J=6.0Hz, 1.6Hz, 2H, Ph-H), 7.18 (dd, J=7.3Hz, 1.7Hz, 2H, Ph-H), 6.96 (d, J =3.1Hz, 2H, Ph-H), 5.22 (s, 2H, OH), 2.03 (s, 6H, Ad-H), 1.86 (s, 12H, Ad-H), 1.72 (d, J = 3.5Hz, 12H, Ad-H).

[0069] Synthesis of C1: Take two 50 mL Schlenk bottles, add L1 compound (1 mmol, 454.4 mg) to one, add tetraisopropyl titanate (0.5 mmol, 142.12 mg) to the other, and then add 40 mL of toluene. Under liquid nitrogen and acetone bath, Ti(O i Pr)4 was slowly added dropwise to the L1 / PhMe solution. After returning to room temperature, the reaction was continued at 60°C for 24 h. A small amount of toluene was removed under reduced pressure, and then 10 mL of n-hexane was added dropwise until turbidity occurred. The solution was then placed in a refrigerator for recrystallization at -30°C for 24 h.

[0070] 1H NMR (400MHz, CDCl3) δ7.32 (s, 4H, Ph-H), 7.18 (d, J=7.7Hz, 2H, Ph-H), 7.08–7.03 (m, 6H, Ph-H), 2.18 (s, 12H, Ad-H), 2.09 (s, 12H, Ad-H), 1.91 (s, 12H, Ad-H). 1.78 (s, 24H, Ad-H). 13 C NMR (101 MHz, CDCl3) δ 131.42 (Ph-C), 130.37 (Ph-C), 129.18 (Ph-C), 128.38 (Ph-C), 124.42 (Ph-C), 121.46 (Ph-C), 43.62 (Ad-C), 40.70 (Ad-C), 37.26 (Ad-C), 36.95 (Ad-C), 29.16 (Ad-C). MALDI-TOF-MS (laser 355 nm, frequency 200 Hz, matrix DHB): C 64 H 72 O4Ti, Calcd, 952.4910, Found, 952.4941. The H NMR spectrum of catalyst C1 is as follows Figure 1 shown.

[0071] Example 2

[0072] The steps of the preparation method for preparing the catalyst for preparing polyethylene wax in this embodiment are as follows:

[0073] The structural formula of the catalyst is shown in C2.

[0074]

[0075] Synthesis of L2: Add biphenol (10 mmol, 1.86 g) and anhydrous aluminum chloride (16 mmol, 2.13 g) to a 100 mL Schlenk flask, and then take 50 mL of dichloromethane. Slowly add tert-butyl chloride ( t Bu-Cl) (80 mmol, 7.41 g), slowly return to room temperature, and continue the reaction for 16 h.

[0076] Adjust the pH to 5-6 with 1M NaHCO₃ solution, extract with dichloromethane (10 mL x 3), combine the organic phases, dry over anhydrous Na₂SO₄, and remove the solvent under reduced pressure. Column chromatography (PE:EA = 20:1) afforded a white solid in a 61% yield. Comparison with a standard H₄ spectrum confirmed the correct compound.

[0077] 1H NMR (400MHz, CDCl3) δ7.37 (d, J=2.5Hz, 2H, Ph-H), 7.34 (d, J=2.5Hz, 2H, Ph-H), 7.27 (d, J=2.6 Hz, 2H, Ph-H), 6.99 (s, 1H, Ph-H), 6.97 (s, 1H, Ph-H), 5.44 (s, 2H, OH), 1.33 (s, 18H, C(CH3)3).

[0078] Synthesis of C2: Take two 50 mL Schlenk bottles, add L2 compound (1 mmol, 298.4 mg) to one, add tetraisopropyl titanate (0.5 mmol, 142.12 mg) to the other, and then add 40 mL of toluene. Under liquid nitrogen and acetone bath, Ti(O i Pr)4 was slowly added dropwise to the L2 / PhMe solution, and after returning to room temperature, the reaction was carried out at 60°C for 24 hours. A small amount of toluene was removed under reduced pressure, and then 10 mL of n-hexane was added dropwise until turbidity occurred. The solution was then placed in a refrigerator for recrystallization at -30°C for 24 hours. The schematic diagram of the C NMR spectrum of catalyst C2 is shown below. Figure 2 The schematic diagram of high-resolution mass spectrometry is shown in Figure 3 shown.

[0079] 1 H NMR (400MHz, CD2Cl2) δ7.35 (dd, J=8.5Hz, 2.5Hz, 4H, Ph-H), 7.27 (d, J=2.6Hz, 4H, Ph-H), 6.94 (d, J=8.5Hz, 4H, Ph-H), 1.32 (s, 36H, C(CH3)3).

[0080] 13 C NMR (101MHz, CDCl3) δ150.76(Ph-C), 144.47(Ph-C), 128.04(Ph-C), 126.76(Ph-C ), 123.66(Ph-C), 116.10(Ph-C), 34.38(C(CH3)3), 31.60(CH3).HRMS(EI), m / z: C 40 H 48 O4Ti, Calcd, 640.3032.

[0081] Example 3

[0082] The steps of the preparation method for preparing the catalyst for preparing polyethylene wax in this embodiment are as follows:

[0083] The structural formula of the catalyst is shown in C3.

[0084]

[0085] Synthesis of L3: Compound L2 (5 mmol, 2.27 g) and adamantane alcohol (10 mmol, 1.52 g) were added sequentially to a 100 mL Schlenk flask, followed by 50 mL of dichloromethane. Concentrated sulfuric acid (5 mmol, 0.25 mL) was slowly added dropwise under an ice-water bath. The mixture was slowly allowed to return to room temperature and the reaction was continued for 48 h. The pH was adjusted to 5-6 with 1 M NaOH solution, and the mixture was extracted with dichloromethane (10 mL x 3). The organic phases were combined, dried over anhydrous Na2SO4, and the solvent removed under reduced pressure. Column chromatography (petroleum ether:ethyl acetate = 50:1) afforded a white solid in a 63% yield.

[0086] 1 H NMR (400MHz, CDCl3) δ7.76 (s, 1H, Ph-H), 7.56 (d, J=8.0Hz, 1H, Ph-H), 7.47 (d, J=6.0Hz, 1H, Ph-H), 7.41 (m, 1H, Ph-H), 6.9 2 (m, 1H, Ph-H), 6.0 (s, 1H, OH-H), 5.31 (s, 1H, OH-H), 2.02 (m, 9H, Ad-H), 1.99 (s, 18H, Ad-H), 1.72 (d, J=2.6Hz, 18H, Ad-H).

[0087] 13 C NMR (101MHz, CDCl3) δ 152.8 (Ph-C), 147.8 (Ph-C), 140.8 (Ph-C), 140.5 (Ph-C), 135.9 (Ph-C), 134.9 (Ph-C), 132.1 (Ph-C), 129.8 (Ph-C), 127.9 (P h-C), 126.8(Ph-C), 126.9(Ph-C), 116.1(Ph-C), 43.5(Ad-C), 43.2(Ad-C), 36.8(Ad-C), 36.7(Ad-C), 36.4(Ad-C), 28.4(Ad-C).HRMS(EI), m / z: C 42 H 52 O2, Calcd, 588.3967.

[0088] Synthesis of C3: Take two 50 mL Schlenk bottles, add L3 compound (1 mmol, 588.4 mg) to one, add tetraisopropyl titanate (0.5 mmol, 142.12 mg) to the other, and then add 40 mL of toluene. Under liquid nitrogen and acetone bath, Ti(O i Pr)4 was slowly added dropwise to the L3 / PhMe solution. After returning to room temperature, the reaction was continued at 60°C for 24 h. A small amount of toluene was removed under reduced pressure, and then 10 mL of n-hexane was added dropwise until turbidity occurred. The solution was then placed in a refrigerator for recrystallization at -30°C for 24 h.

[0089] 1 H NMR (400MHz, CDCl3) δ7.82 (s, 2H, Ph-H), 7.63 (m, 2H, Ph-H), 7.51 (m, 2H, Ph-H), 7.46 (m, 2H, Ph-H), 7.28 (m, 2H, Ph-H), 2.31 ( m, 6H, Ad-H), 2.25 (m, 12H, Ad-H), 1.98 (m, 12H, Ad-H), 2.02 (m, 12H, Ad-H), 1.99 (s, 24H, Ad-H), 1.72 (d, J=2.6Hz, 24H, Ad-H).

[0090] 13 C NMR (101MHz, CDCl3) δ161.4(Ph-C), 153.6(Ph-C), 148.2(Ph-C), 145.3(Ph-C), 140.3 (Ph-C), 138.2(Ph-C), 134.6(Ph-C), 130.1(Ph-C), 129.7(Ph-C), 125.6(Ph-C), 124.2 (Ph-C), 114.1(Ph-C), 45.2(Ad-C), 43.5(Ad-C), 43.6(Ad-C), 43.2(Ad-C), 37.2(Ad- C), 36.9(Ad-C), 36.8(Ad-C), 36.7(Ad-C), 36.4(Ad-C), 28.4(Ad-C).HRMS(EI), m / z: C 84 H 100 O4Ti, Calcd, 1220.7101.

[0091] Example 4

[0092] The steps of the preparation method for preparing the catalyst for preparing polyethylene wax in this embodiment are as follows:

[0093] The structural formula of the catalyst is shown as C4.

[0094]

[0095] Synthesis of C4: Take two 50 mL Schlenk bottles, add L4 compound (the fourth compound) (1 mmol, 454.4 mg) to one, add tetraisopropyl titanate (0.5 mmol, 142.12 mg) to the other, and then add 40 mL of toluene. Under liquid nitrogen and acetone bath, Ti(O i Pr)4 was slowly added dropwise to the L4 / PhMe solution. After returning to room temperature, the reaction was continued at 60°C for 24 h. A small amount of toluene was removed under reduced pressure, and then 10 mL of n-hexane was added dropwise until turbidity occurred. The solution was then placed in a refrigerator for recrystallization at -30°C for 24 h.

[0096] 1 H NMR (400MHz, CDCl3) δ7.36 (dd, J=2.2, 1.1Hz, 4H, Ph-H), 7.06 (dd, J=7.6, 1.9Hz, 4H, Ph-H), 6.84 (d, J=7.5Hz, 4H, Ph-H), 2.50 (s, 12H, CH3).

[0097] 13 C NMR (101MHz, CDCl3) δ156.7(Ph-C), 131.1(Ph-C), 130.1(Ph-C), 129.6(Ph-C), 128.5(Ph-C), 115.2(Ph-C), 21.18(CH3).HRMS(EI), m / z: C 64 H 72 O4Ti, Calcd, 472.1154.

[0098] Example 5

[0099] The steps of the preparation method for preparing the catalyst for preparing polyethylene wax in this embodiment are as follows:

[0100] The structural formula of the catalyst is shown in C5.

[0101] The synthetic route is as follows:

[0102]

[0103] Synthesis of C5: In two 50 mL Schlenk flasks, add compound L2 (1 mmol, 298.4 mg) to one and tetraisopropyl titanate (0.5 mmol, 133.77 mg) to the other, followed by 40 mL of toluene. In a liquid nitrogen / acetone bath, slowly add Zr(NMe2)4 dropwise to the L2 / PhMe solution. After returning to room temperature, react at 60°C for 24 h. Remove the toluene under reduced pressure, then add an equal amount of n-hexane, stir, and allow to stand. The supernatant is filtered, washed with n-hexane (10 mL x 3), and allowed to stand. The lower layer of solid is then drained.

[0104] 1 H NMR (400MHz, CDCl3) δ7.36 (d, J=2.0Hz, 4H, Ph-H), 7.06 (dd, J=7.5, 1.8Hz, 4H, Ph-H), 6.84 (d, J=7.5Hz, 4H, Ph-H), 2.50 (s, 36H, C(CH3)3).

[0105] 13C NMR (101MHz, CDCl3) δ156.67(Ph-C), 131.09(Ph-C), 130.10(Ph-C), 129.62(Ph- C), 128.52(Ph-C), 115.24(Ph-C), 32.3(C(CH3)3), 21.18(CH3).HRMS(EI), m / z: C 40 H 48 O4Zr, Calcd, 682.2600.

[0106] Example 6

[0107] The steps of the preparation method for preparing the catalyst for preparing polyethylene wax in this embodiment are as follows:

[0108] The structural formula of the catalyst is shown in C6.

[0109] The synthetic route is as follows:

[0110]

[0111] Synthesis of C6: In two 50 mL Schlenk flasks, add compound L6 (the fourth compound) (1 mmol, 454.4 mg) to one and zirconium tetraamino (0.5 mmol, 133.77 mg) to the other, followed by 40 mL of toluene. Under a liquid nitrogen and acetone bath, slowly add Zr(NMe2)4 dropwise to the L6 / PhMe solution. After returning to room temperature, react at 60°C for 24 h. Remove the toluene under reduced pressure, add an equal volume of n-hexane, stir for 30 min, and allow to stand. The supernatant is filtered, washed with n-hexane (10 mL x 3), and allowed to stand. The lower layer of solid is then drained.

[0112] 1 H NMR (400MHz, CDCl3) δ7.40 (td, J=2.2, 1.1Hz, 4H, Ph-H), 7.12 (td, J=7.6, 2.1Hz, 4H, Ph-H) H), 6.89 (d, J=7.4Hz, 4H, Ph-H), 2.70–2.62 (m, 8H, CH2CH3), 1.21 (t, J=8.0Hz, 12H, CH3).

[0113] 13 C NMR (101MHz, CDCl3) δ 157.38 (Ph-C), 136.55 (Ph-C), 130.67 (Ph-C), 130.11 (Ph-C), 128.39 (Ph-C), 114.99 (Ph-C), 28.55 (CH2CH3), 15.74 (CH3). HRMS (EI), m / z: C 64 H 72O4Zr, Calcd, 570.1348.

[0114] Example 7

[0115] The steps of the preparation method for preparing the catalyst for preparing polyethylene wax in this embodiment are as follows:

[0116] The structural formula of the catalyst is shown in C7.

[0117] The synthetic route is as follows:

[0118]

[0119] Synthesis of C7: In two 50 mL Schlenk flasks, add compound L1 (1 mmol, 454.4 mg) to one and tetraisopropyl titanate (0.5 mmol, 133.77 mg) to the other, followed by 40 mL of toluene. In a liquid nitrogen / acetone bath, slowly add Zr(NMe2)4 dropwise to the L1 / PhMe solution. After returning to room temperature, react at 60°C for 24 h. Remove the toluene under reduced pressure, add an equal volume of n-hexane, stir for 30 min, and allow to stand. The supernatant is filtered, washed with n-hexane (10 mL x 3), and allowed to stand. The lower layer of solid is then drained.

[0120] 1 H NMR (400MHz, CDCl3) δ7.36 (d, J=2.0Hz, 4H, Ph-H), 7.06 (dd, J=7.5, 1.8Hz, 4H, Ph-H), 6.84 (d, J=7 .5Hz, 4H, Ph-H), 2.21 (s, 12H, Ad-H), 2.11 (s, 12H, Ad-H), 1.93 (s, 12H, Ad-H). 1.81 (s, 24H, Ad-H).

[0121] 13 C NMR (101MHz, CDCl3) δ156.67(Ph-C), 131.09(Ph-C), 130.10(Ph-C), 129.62(Ph-C), 128.52(Ph-C), 11 5.24(Ph-C), 44.62(Ad-C), 41.41(Ad-C), 39.74(Ad-C), 37.02(Ad-C), 30.09(Ad-C).HRMS(EI), m / z: C 64 H 72 O4Ti, Calcd, 994.4478.

[0122] Example 8

[0123] a) In a glove box, accurately weigh 47.624 mg of Catalyst C1 and add 50 mL of toluene to prepare a 1 μmol / mL toluene solution. Dry the solution in a 300 mL reactor at 100°C for 6 h, replacing the atmosphere with ethylene and nitrogen three times. Sequentially, add 30 mL of toluene, 3 mL of sesquiethylaluminum chloride (Al / Ti = 600), and 20 mL of toluene to an addition funnel, which is then placed in the reactor.

[0124] Add 5 mL of the Cl / PhMe solution to the addition funnel. Raise the temperature to 100°C and adjust the pressure to 2 MPa and maintain it stable. Connect a mass flow meter and wait for the instantaneous flow rate to stabilize at zero before adding the Cl / PhMe solution. Polymerize for 30 minutes. After the polymerization is complete, turn off the ethylene gas, reduce the temperature to 40°C, release the pressure, and stop stirring. Slowly add a hydrochloric acid-ethanol solution to quench the reaction. Place the polymer in a beaker and stir for 6 hours. Filter to remove any excess toluene and ethanol.

[0125] The polymer was dried under vacuum at 60 °C for 10 h and weighed to obtain 7.274 g. The catalytic activity was calculated to be 2.910×10 6 g / (mol·Ti·h). (Wherein: A: catalytic activity of the catalyst, g / (mol·Ti·h); n: amount of catalyst, mol; M: mass of the obtained polyethylene, g; t: polymerization reaction time, h).

[0126] The molecular weight of the polyethylene wax polymer Mw = 7505 g / mol, where Mw is the weight average molecular weight of the polymer, obtained by GPC (Gel Permeation Chromatography-Mass Spectrometry). m =125.7℃, T m is the melting temperature of the polymer, obtained by DSC (Differential Scanning Calorimetry), polymer X c =75.0%(X c is the crystallinity of the polymer, measured by DSC).

[0127] The DSC spectrum of the polyethylene wax polymer prepared in Example a) is shown in FIG. Figure 4 As shown, the GPC spectrum diagram is as follows Figure 5 As shown in the figure, "dw / dlogM" represents the derivative of the weight distribution logarithmic molecular weight, which reflects the mass change rate and distribution of the polymer at a specific molecular weight; "Mw" represents the molecular weight, which represents the statistical average of the molecular weight distribution of the polymer; "Ht%" represents the proportion of the high molecular weight part of the polymer. Figure 5In the figure, the blue line represents the signal intensity of each molecular weight, with higher values ​​indicating a higher molecular weight. The red line represents the cumulative score, called the cumulative integral curve. This curve allows for direct estimation of the proportion of molecules in any molecular weight range within the total molecular weight.

[0128] The only difference between b) and a) is that the amount of co-catalyst used is 4 mL of sesquiethylaluminum chloride, making Al / Fe = 800:1. Polymerization activity: 1.935×10 6 g / (mol·Ti·h), Mw=5412 g / mol, polymer T m =120.1℃,X c =85.4%.

[0129] The only difference between c) and a) is that the amount of co-catalyst used is 5 mL of sesquiethylaluminum chloride, so that Al / Fe = 1000:1. Polymerization activity: 1.764×10 6 g / (mol·Ti·h), polymer T m =116.4℃,X c =76.2%.

[0130] The only difference between d) and a) is that the amount of co-catalyst used is 2 mL of sesquiethylaluminum chloride, so that Al / Fe = 400:1. Polymerization activity: 1.212×10 6 g / (mol·Ti·h), polymer T m =126.3℃, X c =80.5%.

[0131] The difference between e) and a) is that the amount of co-catalyst used is 1 mL of sesquiethylaluminum chloride, so that Al / Fe = 200:1. Polymerization activity: 0.531×10 6 g / (mol·Ti·h), polymer T m =129.6℃,X c =73.1%.

[0132] f) differs from a) only in that the polymerization temperature is 110°C. Polymerization activity: 1.626×10 6 g / (mol·Ti·h), Mw=4591 g / mol, polymer T m =116.4℃,X c =76.5%.

[0133] The only difference between g) and a) is that the polymerization temperature is 120°C. Polymerization activity: 0.664×10 6 g / (mol·Ti·h), Mw=3192g / mol, polymer T m =118.1℃,Xc =71.2%.

[0134] h) differs from a) only in that the polymerization temperature is 90°C. Polymerization activity: 2.783×10 6 g / (mol·Ti·h), polymer T m =128.6℃,X c =95.5%.

[0135] The only difference between i) and a) is that the polymerization temperature is 80°C. Polymerization activity: 1.917×10 6 g / (mol·Ti·h), polymer T m =122.6℃,X c =76.6%.

[0136] j) differs from a) only in that the ethylene pressure is 1.5 MPa. Polymerization activity: 2.317×10 6 g / (mol·Ti·h), Mw=7914 g / mol, polymer T m =127.1℃,X c =83.1%.

[0137] k) differs from a) only in that the ethylene pressure is 1.0 MPa. Polymerization activity: 1.873×10 6 g / (mol·Ti·h), polymer T m =128.4℃,X c =85.2%.

[0138] The only difference between l) and a) is that the ethylene pressure is 2.5 MPa. Polymerization activity: 2.763×10 6 g / (mol·Ti·h), polymer T m =123.8℃, X c =71.2%.

[0139] Example 9

[0140] The only difference from Example 8 (a) is that the main catalyst is C2, and the polymerization activity is 2.442×10 6 g / (mol·Ti·h), Mw=6379 g / mol, polymer T m =126.1℃,X c =81.8%.

[0141] Example 10

[0142] The only difference from Example 8 (a) is that the main catalyst is C3, and the polymerization activity is 3.014×10 6g / (mol·Ti·h), Mw=5874 g / mol, polymer T m =125.2℃, X c =89.2%.

[0143] Example 11

[0144] The only difference from Example 8 (a) is that the main catalyst is C4, and the polymerization activity is 1.863×10 6 g / (mol·Ti·h), Mw=8613 g / mol, polymer T m =125.6℃,X c =77.2%.

[0145] Example 12

[0146] a) In a glove box, accurately weigh 34.113 mg of catalyst C5 and add 50 mL of toluene to prepare a 1 μmol / mL toluene solution. Dry the solution in a 300 mL reactor at 100°C for 6 h, replacing the atmosphere with ethylene and nitrogen three times. Add 30 mL of toluene, 3 mL of sesquiethylaluminum chloride (Al / Ti = 600), and 20 mL of toluene to an addition funnel, which is then placed in the reactor.

[0147] Add 5 mL of the C5 / PhMe solution to the addition funnel. Raise the temperature to 100°C and adjust the pressure to 2 MPa and maintain it stable. Connect a mass flow meter and wait for the instantaneous flow rate to stabilize at zero before adding the C5 / PhMe solution. Polymerize for 30 minutes. After the polymerization is complete, turn off the ethylene gas, reduce the temperature to 40°C, release the pressure, and stop stirring. Slowly add a hydrochloric acid-ethanol solution to quench the reaction. Place the polymer in a beaker and stir for 6 hours. Filter to remove any excess toluene and ethanol.

[0148] The polymer was dried under vacuum at 60 °C for 10 h and weighed to obtain 6.329 g. The catalytic activity was calculated to be 2.532 × 10 6 g / (mol·Zr·h). (Wherein: A: catalytic activity of the catalyst, g / (mol·Zr·h); n: amount of catalyst, mol; M: mass of the obtained polyethylene, g; t: polymerization reaction time, h). Polymer molecular weight Mw = 7396 g / mol (Mw is the weight average molecular weight of the polymer, obtained by GPC test), polymer T m =124.1℃(T m is the melting temperature of the polymer, obtained by DSC test), polymer X c =85.8%(X c The DSC spectrum of the polyethylene wax polymer prepared in Example a) is shown in FIG. Figure 6As shown, the GPC spectrum diagram is as follows Figure 7 shown.

[0149] The only difference between b) and a) is that the polymerization temperature is 110°C. Polymerization activity: 2.164×10 6 g / (mol·Zr·h), Mw=6396 g / mol, polymer T m =121.3℃,X c =82.1%.

[0150] The only difference between c) and a) is that the polymerization temperature is 120°C. Polymerization activity: 1.539×10 6 g / (mol·Zr·h), polymer T m =116.3℃,X c =79.5%.

[0151] The only difference between d) and a) is that the polymerization temperature is 90°C. Polymerization activity: 2.243×10 6 g / (mol·Zr·h), polymer T m =126.2℃,X c =87.3%.

[0152] e) differs from a) only in that the polymerization temperature is 80°C. Polymerization activity: 1.825×10 6 g / (mol·Zr·h), polymer T m =127.1℃,X c =88.2%.

[0153] f) differs from a) only in that the amount of co-catalyst used is 4 mL of sesquiethylaluminum chloride, making Al / Fe = 800:1. Polymerization activity: 2.075×10 6 g / (mol·Zr·h), polymer T m =120.1°C. Crystallinity X c =81.2%.

[0154] The only difference between g) and a) is that the amount of co-catalyst used is 2 mL of sesquiethylaluminum chloride, so that Al / Fe = 400:1. Polymerization activity: 2.196×10 6 g / (mol·Zr·h), polymer T m =127.1°C. Crystallinity X c =86.3%.

[0155] h) differs from a) only in that the amount of co-catalyst used is 1 mL of sesquiethylaluminum chloride, with Al / Fe = 200:1. Polymerization activity: 1.862×10 6g / (mol·Zr·h), polymer T m =128.4°C. Crystallinity X c =81.2%.

[0156] Example 13

[0157] The only difference from Example 12 a) is that the main catalyst is C6, and the polymerization activity is 2.142×10 6 g / (mol·Zr·h), Mw=7513 g / mol, polymer T m =123.2℃,X c =75.3%.

[0158] Example 14

[0159] The only difference from Example 12a) is that the main catalyst is C7, and the polymerization activity is 2.892×10 6 g / (mol·Zr·h), Mw=6942g / mol, polymer T m =126.1℃,X c =81.3%.

[0160] From the above description, it can be seen that the above-mentioned embodiments of the present invention achieve the following technical effects: the catalyst for preparing polyethylene wax in the present application contains a large steric hindered group on the benzene ring, and the catalyst synthesis process of the present application is simple and low-cost, which further reduces the preparation cost of the catalyst and the cost of use in the polyethylene wax synthesis reaction. The catalyst of the present application is combined with the low-cost co-catalyst sesquiethylaluminum chloride to successfully prepare polyethylene wax, and the catalyst has high catalytic activity and good catalytic effect. Moreover, by adjusting the type of large steric hindered substituents on the biphenyl ring of the catalyst of the present application, controlling the spatial and electronic effects of the metal center, and then achieving the regulation of the molecular weight and molecular weight distribution of the polyethylene polymer, it is possible to obtain a highly linear low molecular weight polyethylene wax with a narrow molecular weight distribution, controllable molecular weight, high crystallinity and good thermal stability.

[0161] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A catalyst for preparing polyethylene wax, characterized in that The structure of the catalyst is shown in the following formula I: wherein R1 is selected from hydrogen, n-alkyl, adamantyl or tert-butyl; R2 is selected from hydrogen, n-alkyl, adamantyl or tert-butyl; The n-alkyl group includes methyl, ethyl, n-propyl, n-butyl, n-pentyl or n-hexyl; M is selected from Ti or Zr.

2. The catalyst according to claim 1, characterized in that The catalyst comprises:

3. A method for preparing a catalyst for preparing polyethylene wax, characterized in that: The structural formula of the catalyst is shown in Formula I: The preparation method comprises: Under a first atmosphere, mixing and stirring the first compound and the second compound to obtain the catalyst; The first compound includes tetraisopropyl titanate or tetraisopropyl zirconate; The structural formula of the second compound is shown in Formula II: wherein R3 is selected from hydrogen, n-alkyl, adamantyl or tert-butyl; R4 is selected from hydrogen, n-alkyl, adamantyl or tert-butyl; R5 is selected from hydrogen, n-alkyl, adamantyl or tert-butyl; R6 is selected from hydrogen, n-alkyl, adamantyl or tert-butyl; The n-alkyl group includes methyl, ethyl, n-propyl, n-butyl, n-pentyl or n-hexyl.

4. The preparation method according to claim 3, characterized in that The preparation method of the second compound comprises: a) mixing a third compound, a fourth compound, and a Lewis acid in a solvent under a first atmosphere and performing a first reaction to obtain a first reaction system; b) adjusting the pH of the first reaction system to 5-6, and then purifying the first reaction system to obtain the second compound; Wherein, the third compound comprises an adamantane compound or a tert-butyl compound; The fourth compound includes biphenol; Preferably, the adamantane compound comprises one or more of adamantane alcohol, chloroadamantane, bromoadamantane or iodoadamantane; Preferably, the tert-butyl compound includes one or more of tert-butyl chloride, tert-butyl bromide or tert-butyl iodide.

5. The preparation method according to claim 4, characterized in that The temperature of the first reaction is 20 to 50° C., and the time of the first reaction is 1 to 10 hours; Preferably, the solvent comprises one or more of dichloromethane, carbon disulfide, carbon tetrachloride or nitrobenzene; Preferably, the Lewis acid comprises one of concentrated sulfuric acid, AlCl3, FeCl3, BBr3 or BCl3.

6. The preparation method according to claim 3 or 4, characterized in that The first atmosphere comprises nitrogen and / or an inert gas; Preferably, the inert gas includes argon and / or helium.

7. The preparation method according to claim 3, characterized in that The preparation method comprises: S1) under the first atmosphere, mixing the first compound and the second compound at -75 to -60°C to obtain a first mixed system, and stirring until the temperature of the first mixed system rises to 15 to 30°C to obtain a second mixed system; S2) heating the second mixed system to 50-80° C. to perform a second reaction to obtain the catalyst; Preferably, the second reaction time is 10-24 hours.

8. A catalyst composition for preparing polyethylene wax, characterized in that: The catalytic composition includes a first catalyst and a second catalyst; The first catalyst comprises the catalyst for preparing polyethylene wax according to claim 1 or 2, or a catalyst prepared by the method for preparing the catalyst for preparing polyethylene wax according to any one of claims 3 to 7; The second catalyst comprises an aluminum alkyl.

9. The catalyst composition according to claim 8, characterized in that In the catalyst composition, the molar ratio of the first catalyst to the second catalyst is 1:100 to 6000.

10. A method for preparing polyethylene wax, characterized in that: The synthesis method comprises: utilizing The catalyst for preparing polyethylene wax according to any one of claims 1 or 2, or The catalyst obtained by the method for preparing a catalyst for preparing polyethylene wax according to any one of claims 3 to 7, or The catalyst composition for preparing polyethylene wax according to any one of claims 8 or 9 As a catalyst, it catalyzes the polymerization reaction of ethylene to synthesize the polyethylene wax.

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