Ether metal complexes, methods for their preparation and use

Abstract

The application relates to the technical field of olefin polymerization, and discloses an ether metal complex and a preparation method and application thereof. The structural formula of the ether metal complex is shown in formula (I): wherein R1, R2, R3 and R4 are each independently selected from one of hydrogen, C1-C10 alkyl and halogen; X is each selected from O or S; and M is selected from IVB group metal. The ether metal complex is applied to ethylene polymerization as a catalyst, has high reactivity, good thermal stability, shows extremely strong control performance on the molecular weight of polyethylene wax, and highly linear low-molecular-weight polyethylene is obtained. Formula (I)

Description

Technical Field

[0001] This invention relates to the field of olefin polymerization technology, specifically to an ether-based metal complex, its preparation method, and its application. Background Technology

[0002] The development of polyolefin catalysts has spanned nearly a century, resulting in Ziegler-Natta catalysts, metallocene catalysts, and transition metal catalysts. However, whether using traditional Ziegler-Natta catalysts or metallocene catalysts to prepare polyethylene wax, a large amount of hydrogen gas needs to be introduced into the system. This reduces polymerization activity, broadens the polymer molecular weight distribution, and hydrogen gas can convert ethylene to ethane, reducing the utilization rate of ethylene monomers. Furthermore, the process conditions for producing low molecular weight polyethylene using metallocene catalysts are demanding, and the required co-catalyst, methylaluminoxane (MAO), is expensive. While using Ziegler-Natta catalysts can reduce costs, the larger polymer molecular weight results in low molecular weight polyethylene with excessively high melting points and viscosity, leading to processing difficulties. In addition, the co-catalysts used are alkylaluminoxanes such as MAO and MMAO, which are expensive and unsuitable for industrial application. Summary of the Invention

[0003] The purpose of this invention is to overcome the problems of existing olefin catalysts in olefin polymerization reactions, such as low polymerization catalytic activity, low ethylene monomer utilization, wide molecular weight distribution of polyethylene wax, low product purity, and high cost. This invention provides an ether-based metal complex, its preparation method, and its application. This ether-based metal complex not only retains the activity of a single-center catalyst but also exhibits low sensitivity to water and oxygen, making it easier to preserve than metallocene catalysts. By adjusting the substituents and controlling the steric and electronic effects on the ligands, the molecular weight and distribution of the polymer can be regulated, enabling the production of low molecular weight polyethylene.

[0004] To achieve the above objectives, the first aspect of the present invention provides an ether-based metal complex with the structural formula shown in formula (I): Formula (I) R1, R2, R3 and R4 are each independently selected from hydrogen, C1-C10 alkyl groups and halogens; X is selected from either O or S; M is selected from group IVB metals.

[0005] Preferably, R1, R2, R3 and R4 are each independently selected from one of hydrogen, adamantyl, tert-butyl and chlorine.

[0006] Preferably, M is selected from Ti or Zr.

[0007] Preferably, it is selected from the group consisting of the following complexes: Complex 1: The complex shown in formula (I), wherein M is Ti, R2 and R4 are both H, R1 and R3 are both adamantyl alkyl groups, and X is O; Complex 2: The complex shown in formula (I), wherein M is Ti, R2 and R4 are both H, R1 and R3 are both tert-butyl, and X is O; Complex 3: The complex shown in formula (I), wherein M is Ti, R4 is H, R1, R2 and R3 are all adamantyl alkyl groups, and X is O; Complex 4: The complex shown in formula (I), where M is Ti, R1, R2, R3 and R4 are all chlorine, and X is S.

[0008] A second aspect of the present invention provides a method for preparing the above-mentioned ether metal complex, the method comprising: performing a complexation reaction between the compound of formula (II) and a metal salt of M; Formula (II); The definitions of R1, R2, R3, R4 and X are the same as in claim 1; The M metal salt is selected from group IVB metals.

[0009] Preferably, the specific process of the method includes: adding a solution containing the metal salt of M dropwise to a solution containing the compound shown in formula (II) at -85 to -75°C, followed by a complexation reaction at 55-65°C.

[0010] Preferably, the molar ratio of the M metal salt to the compound shown in formula (II) is 1:(2-2.2), wherein the M metal salt is calculated as M metal element.

[0011] Preferably, the M metal salt is selected from Ti(O) i Pr)4 and / or Zr(O) i Pr)4.

[0012] Preferably, in the solution containing the metal salt M, the solvent is selected from at least one of toluene, chloroform, n-heptane, and n-hexane; Preferably, in the solution containing the compound shown in formula (II), the solvent is selected from at least one of toluene, chloroform, n-heptane and n-hexane.

[0013] A third aspect of the present invention provides a method for preparing polyethylene, wherein ethylene is polymerized in the presence of a catalyst containing the above-mentioned ether metal complex.

[0014] Compared with the prior art, the present invention has the following technical effects: (1) The ether metal complexes of the present invention contain sterically hindered substituents and can be used to prepare low molecular weight polyethylene; and the preparation process has the advantages of mild reaction conditions, short synthesis route, simple synthesis process and low industrial use cost. (2) In the ether metal complexes described in this invention, in a preferred case, such complexes have sterically hindered substituents with multiple substitutions, such as adamantyl alkyl and tert-butyl, and have a single catalytic active center. The molecular weight of the polymer can be controlled by changing the ligand structure and polymerization reaction conditions. In a more preferred case, while using the ether metal complexes described in this invention, inexpensive sesquiethyl aluminum chloride is used instead of traditional cocatalysts such as MAO and MMAO, and it has the advantages of high catalytic activity and stable performance. (3) In a preferred embodiment, the ether metal complex of the present invention contains sterically hindered substituents and can be used as a catalyst in the polymerization reaction of ethylene. It has high reactivity and good thermal stability, and exhibits strong control over the molecular weight of polyethylene wax, thus obtaining highly linear low molecular weight polyethylene. Attached Figure Description

[0015] Figure 1 The hydrogen spectrum of compound L3 of formula (II) prepared in Example 1 is shown. Figure 2 This is the mass spectrum of compound L3 of formula (II) prepared in Example 1; Figure 3 The hydrogen spectrum of complex C3 of formula (I) prepared in Example 1 is shown. Figure 4 The carbon spectrum of the complex C3 of formula (I) prepared in Example 1 is shown. Figure 5 The hydrogen spectrum of complex C6 of formula (I) prepared in Example 2 is shown. Figure 6 The carbon spectrum of the complex C6 of formula (I) prepared in Example 2 is shown. Figure 7 The hydrogen spectrum of the complex C8 of formula (I) prepared in Example 3 is shown below. Figure 8 The hydrogen spectrum of compound L9, which is shown in formula (II) prepared in Example 4; Figure 9 This is the carbon spectrum of compound L9 of formula (II) prepared in Example 4; Figure 10 This is the mass spectrum of compound L9 of formula (II) prepared in Example 4; Figure 11 The hydrogen spectrum of complex C9 of formula (I) prepared in Example 3 is shown. Figure 12 The carbon spectrum of the complex C9 of formula (I) prepared in Example 3 is shown. Figure 13 This is the mass spectrum of the complex C9 of formula (I) prepared in Example 3; Figure 14 This is a schematic diagram of the DSC test results of the complex C3 of formula (I) prepared in Example 1 at 90°C. Figure 15 This is a schematic diagram of the DSC test results of the complex C3 of formula (I) prepared in Example 1 at 100°C. Figure 16 This is a schematic diagram of the DSC test results of the complex C3 of formula (I) prepared in Example 1 at 110°C. Figure 17 This is a schematic diagram of the DSC test results of the complex C3 of formula (I) prepared in Example 1 at 120°C. Figure 18 This is a schematic diagram of the GPC test results of the polymer obtained by the complex C8 of formula (I) prepared in Example 3 at 100°C. Detailed Implementation

[0016] The following provides a detailed description of specific embodiments of the present invention. It should be understood that the specific embodiments described herein are for illustrative and explanatory purposes only and are not intended to limit the scope of the invention.

[0017] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0018] The structural formula of the ether-based metal complex of the present invention is shown in formula (I): Formula (I) R1, R2, R3 and R4 are each independently selected from hydrogen, C1-C10 alkyl groups and halogens; X is selected from O or S; M is selected from group IVB metals.

[0019] The ether-based metal complexes described in this invention not only retain the activity of single-center catalysts but also exhibit low sensitivity to water and oxygen, making them easier to preserve than metallocene catalysts. Furthermore, in preferred embodiments, by adjusting the substituents R1, R2, R3, and R4, the steric and electronic effects on the ligands can be controlled, thereby regulating the molecular weight and distribution of the polymer, resulting in the production of low-molecular-weight polyethylene.

[0020] In the ether-based metal complexes described in this invention, R1, R2, R3, and R4 can each be independently selected from one of hydrogen, adamantyl, tert-butyl, and chlorine, preferably one of adamantyl, tert-butyl, and chlorine. M can be selected from Ti or Zr, preferably Ti.

[0021] In the ether-based metal complexes described in this invention, the complexes are selected from the group consisting of the following complexes: Complex 1: The complex shown in formula (I), wherein M is Ti, R2 and R4 are both H, R1 and R3 are both adamantyl alkyl groups, and X is O; Complex 2: The complex shown in formula (I), wherein M is Ti, R2 and R4 are both H, R1 and R3 are both tert-butyl, and X is O; Complex 3: The complex shown in formula (I), wherein M is Ti, R4 is H, R1, R2 and R3 are all adamantyl alkyl groups, and X is O; Complex 4: The complex shown in formula (I), where M is Ti, R1, R2, R3 and R4 are all chlorine, and X is S.

[0022] The present invention also provides a method for preparing the above-mentioned ether metal complex, the method comprising: performing a complexation reaction between the compound shown in formula (II) and a metal salt of M; Formula (II); Wherein, the definitions of R1, R2, R3, R4 and X are the same as in claim 1; M in the M metal salt is selected from group IVB metals.

[0023] According to the method described in this invention, the ether-based metal complex obtained by complexing the compound shown in formula (II) with the metal salt of M retains the activity of a single-center catalyst, and the molecular weight of the polymer can be controlled by changing the ligand structure and polymerization reaction conditions. When used as a catalyst in the polymerization reaction of ethylene, it has high reactivity and good thermal stability, and exhibits extremely strong control performance on the molecular weight of polyethylene wax, resulting in highly linear low molecular weight polyethylene.

[0024] In the method described in this invention, the specific process may include: adding a solution containing the metal salt M dropwise to a solution containing the compound shown in formula (II) at -85 to -75°C, followed by a complexation reaction at 55-65°C. The complexation reaction may take 20-30 hours, preferably 24-30 hours. The method may further include: allowing the product obtained after the complexation method to stand, then removing part of the solvent under vacuum, then adding n-hexane until a solid appears, then recrystallizing at -25 to -15°C for 40-60 hours, and then separating the solid phase by filtration to obtain the compound shown in formula (I). The complexation reaction may be carried out under an inert atmosphere.

[0025] In this invention, the inert atmosphere may be selected from at least one of nitrogen atmosphere, argon atmosphere, helium atmosphere and neon atmosphere.

[0026] In the method described in this invention, the molar ratio of the amount of the M metal salt to the compound shown in formula (II) can be 1:(2-2.2), specifically for example, 1:2, 1:2.05, 1:2.1, 1:2.15 or 1:2.2, wherein the M metal salt is calculated as the M metal element.

[0027] In the method described in this invention, in order to improve the activity of ethylene polymerization, the M metal salt is preferably selected from Ti(O) i Pr)4 (tetraisopropyl titanate) and / or Zr(O) i Pr)4 (tetraisopropyl zirconate), more preferably Ti(O) i Pr)4.

[0028] In the method described in this invention, the solvent in the solution containing the metal salt M can be selected from at least one of toluene, chloroform, n-heptane, and n-hexane, preferably toluene. The concentration of the metal salt M in the solution can be 0.01-0.05 mol / L, preferably 0.025-0.05 mol / L, wherein the metal salt M is calculated as the element M.

[0029] In the method described in this invention, the solvent in the solution containing the compound shown in formula (II) may be selected from at least one of toluene, chloroform, n-heptane, and n-hexane, preferably toluene. The concentration of the compound shown in formula (II) in the solution may be 0.03-0.1 mol / L, preferably 0.05-0.1 mol / L.

[0030] In some embodiments, in the compound shown in formula (II), R2 and R4 are both H, R1 and R3 are both adamantyl, and X is O; the method further includes preparing 2,2'-dihydroxy-5,5'-diadamantyl diphenyl ether according to the following process: reacting 2,2'-dihydroxy-5,5'-diadamantyl diphenyl ether with adamantyl alcohol under an inert atmosphere; wherein the molar ratio of the 2,2'-dihydroxy-5,5'-diadamantyl diphenyl ether to the adamantyl alcohol is 1:(2.8-3.5). The specific reaction process for preparing 2,2'-dihydroxy-5,5'-diadamantyl diphenyl ether is shown in the following reaction formula: .

[0031] In a specific embodiment, the reaction process of 2,2'-dihydroxydiphenyl ether and adamantanol includes: mixing 2,2'-dihydroxydiphenyl ether, adamantanol, and dichloromethane under an inert atmosphere; placing the resulting mixture in an ice-water bath; adding sulfuric acid dropwise to the mixture; restoring the temperature to 15-35°C; and continuing the reaction at 15-35°C for 45-50 hours. The pH is then adjusted to 5-6 using an aqueous sodium hydroxide solution, followed by extraction with dichloromethane. The organic phases are combined, dried over anhydrous Na₂SO₄, and the solvent is removed. Silica gel column chromatography is performed using petroleum ether and ethyl acetate as eluents. The ratio of 2,2'-dihydroxydiphenyl ether to dichloromethane is (4-6) mmol:50 mL; the concentration of sulfuric acid is 1.5-2 mol / L; the volume ratio of sulfuric acid to dichloromethane is (0.25-0.35):50; and the concentration of the aqueous sodium hydroxide solution is 0.5-1.5 mol / L.

[0032] In other embodiments, in the compound shown in formula (II), R2 and R4 are both H, R1 and R3 are both tert-butyl, and X is O; the method further includes preparing 2,2'-dihydroxy-5,5'-ditert-butyl diphenyl ether according to the following procedure: 2,2'-dihydroxy diphenyl ether, aluminum chloride, and dichloromethane are mixed under an inert atmosphere, and the resulting mixture is placed in a liquid nitrogen acetone bath and added dropwise. t Bu-Cl was restored to 15-35℃, and the reaction was continued at 15-35℃ for 15-20 h. The pH was then adjusted to 5-6 with sodium bicarbonate aqueous solution, followed by extraction with dichloromethane. The organic phases were combined, dried over anhydrous Na2SO4 to remove the solvent, and silica gel column chromatography was performed using petroleum ether and ethyl acetate as eluents. The 2,2'-dihydroxydiphenyl ether, the aluminum chloride, and the... t The molar ratio of Bu-Cl used is 1:(1.5-2):(8-10). The specific reaction process for preparing 2,2'-dihydroxy-5,5'-di-tert-butyl diphenyl ether is shown in the following reaction formula: .

[0033] In other embodiments, in the compound shown in formula (II), R4 is H, R1, R2, and R3 are all adamantyl, and X is O; the method further includes preparing 2,2'-dihydroxy-3,5,5'-triadamantyl diphenyl ether according to the following procedure: 2,2'-dihydroxy-5,5'-diadamantyl diphenyl ether, adamantyl alcohol, and dichloromethane are mixed under an inert atmosphere, the resulting mixture is placed in an ice-water bath, and sulfuric acid is added dropwise to the resulting mixture, the temperature is restored to 15-35°C, and then the reaction is continued at 15-35°C for 70-75 h. The pH is then adjusted to 5-6 with an aqueous sodium hydroxide solution, and then extracted with dichloromethane. The organic phases were combined, dried over anhydrous Na2SO4, and the solvent was removed. Petroleum ether and ethyl acetate were used as eluents for silica gel column chromatography. The molar ratio of 2,2'-dihydroxy-5,5'-diadamantyl diphenyl ether to adamantane alcohol was 1:(2.8-3.5); the molar ratio of 2,2'-dihydroxy-5,5'-diadamantyl diphenyl ether to dichloromethane was (4-6) mmol:50 mL; the concentration of sulfuric acid was 1.5-2 mol / L; the volume ratio of sulfuric acid to dichloromethane was (0.25-0.35):50; and the concentration of the sodium hydroxide aqueous solution was 0.5-1.5 mol / L. The specific reaction process for preparing 2,2'-dihydroxy-3,5,5'-triadamantyl diphenyl ether is shown in the following reaction formula: .

[0034] In a specific embodiment, the method further includes preparing 2,2'-dihydroxydiphenyl ether according to the following process: Tetrahydrofuran, diphenyl ether, and tetramethylethylenediamine (TMEDA) are mixed under an inert atmosphere, and the resulting mixture is placed in a liquid nitrogen-acetone bath. A solution containing n-butyllithium is then added dropwise to the resulting mixture, and the temperature is restored to 15-35°C. The reaction is then continued at 15-35°C for 7-10 hours. The resulting product is then placed in a liquid nitrogen-acetone bath, and B(OMe)3 (trimethyl borate) is added dropwise to the resulting product, and the temperature is restored to 15°C. The reaction was carried out at -35℃, followed by a further reaction at 15-35℃ for 5-8 hours. Then, an aqueous sodium hydroxide solution was added dropwise at 15-35℃, and the reaction continued for 1-2 hours. The resulting product was then placed in an ice-water bath, and an aqueous hydrogen peroxide solution was added dropwise, with the reaction continuing for 4-7 hours. The solvent was removed, and the product was extracted with diethyl ether to remove the organic phase. The aqueous phases were combined, and hydrochloric acid was slowly added dropwise until no more white precipitate formed. The solid phase was separated by filtration, and silica gel column chromatography was performed using petroleum ether and ethyl acetate as eluents. The concentration of the hydrochloric acid was 0.1-10 mol / L. The specific reaction process for preparing 2,2'-dihydroxydiphenyl ether is shown in the following reaction formula:

[0035] The present invention also provides a method for preparing polyethylene, wherein ethylene is polymerized in the presence of a catalyst containing the above-mentioned ether metal complex.

[0036] According to the method described in this invention, ethylene polymerization is carried out using a catalyst containing the above-mentioned ether metal complex. The catalyst exhibits high reactivity and good thermal stability, and demonstrates a strong ability to regulate the molecular weight of polyethylene wax, resulting in highly linear low molecular weight polyethylene.

[0037] In the method described in this invention, the catalyst containing the above-mentioned ether-based metal complex may further contain a co-catalyst. The co-catalyst may be selected from at least one of methylaluminoxane, sesquiethylaluminum chloride, and modified methylaluminoxane, preferably sesquiethylaluminum chloride. In the catalyst containing the above-mentioned ether-based metal complex, the molar ratio of the co-catalyst to the ether-based metal complex is (400-1000):1, wherein the co-catalyst is calculated based on aluminum, and the ether-based metal complex is calculated based on metal M.

[0038] In the method described in this invention, the polymerization reaction is carried out under an inert atmosphere. The inert atmosphere may be selected from at least one of nitrogen, argon, helium, and neon atmospheres. The conditions for the polymerization reaction include: a temperature of 80-120°C, preferably 100-110°C; and a pressure of 1.5-2.5 MPa, preferably 2-2.5 MPa. In this document, the pressure is gauge pressure.

[0039] The following examples further illustrate the ether-based metal complexes, their preparation methods, and applications according to the present invention. These examples are implemented based on the technical solution of the present invention, providing detailed implementation methods and specific operating procedures; however, the scope of protection of the present invention is not limited to the following examples.

[0040] Unless otherwise specified, the experimental methods used in the following embodiments are conventional methods in the art. Unless otherwise specified, the experimental materials used in the following embodiments are commercially available.

[0041] Example 1 (1) Under a nitrogen atmosphere, 50 mL of THF, diphenyl ether (10 mmol, 1702 mg), and TMEDA (25 mmol, 2905 mg) were added sequentially to a 100 mL Schlenk flask and mixed. The resulting mixture was placed in a liquid nitrogen acetone bath. Then, n-butyllithium solution (25 mmol, 2.5 mol / L, n-hexane, 10 mL) was added dropwise to the mixture. After restoring to 25 °C, the reaction was continued at 25 °C for 8 h. The resulting product was then placed in a liquid nitrogen acetone bath. B(OMe)3 (40 mmol, 4156 mg) was slowly added dropwise to the resulting product. The temperature was slowly restored to 25 °C, and the reaction was continued at 25 °C for 6 h. Sodium hydroxide aqueous solution (60 mmol, 1 mol / L, 2400 mg) was added dropwise at 25 °C. The product was reacted at 25°C for 1 hour, and then placed in an ice-water bath. Hydrogen peroxide solution (34 wt%, 60 mmol, 6 mL) was slowly added dropwise to the product, and the reaction continued for 5 hours. THF was removed under reduced pressure, and the product was extracted three times with 10 mL of diethyl ether each time to remove the organic phase. The aqueous phases were combined, and 5 mol / L hydrochloric acid was slowly added dropwise to the aqueous phase until no more white precipitate was formed. The obtained white crude product was filtered, and then subjected to silica gel column chromatography (volume ratio of petroleum ether to ethyl acetate was 40:1) using petroleum ether and ethyl acetate as eluents. 1260 mg of a white solid was obtained, with a yield of 62.4%. The result, according to the standard 1H NMR spectrum, was 2,2'-dihydroxydiphenyl ether. 1 H NMR (400 MHz, CDCl3) δ7.05 (d, J = 4.3 Hz, 2H, Ph- H ), 7.04 (d, J = 3.2 Hz, 2H, Ph- H ), 6.85 (d, J = 4.2 Hz, 2H, Ph- H ), 6.83 (d, J = 3.1 Hz, 2H, Ph- H ), 5.98 (s, 2H, -O) H ).); (2) Under a nitrogen atmosphere, 2,2'-dihydroxydiphenyl ether (5 mmol, 1010 mg) and adamantanol (15 mmol, 2283 mg) were added sequentially to a 100 mL Schlenk flask, followed by the addition of 50 mL of dichloromethane and mixing. The resulting mixture was placed in an ice-water bath, and concentrated sulfuric acid (5 mmol, 0.3 mL) was slowly added dropwise. The temperature was slowly restored to 25 °C, and the reaction was continued at 25 °C for 48 h. The pH was then adjusted to 5.5 with a 1 mol / L sodium hydroxide aqueous solution, and the mixture was extracted three times with 10 mL of dichloromethane each time. The organic phases were combined, dried over anhydrous Na2SO4, and the solvent was removed under reduced pressure. Silica gel column chromatography was performed using petroleum ether and ethyl acetate as eluents (volume ratio of petroleum ether to ethyl acetate was 60:1). 1524 mg of a white solid was obtained, with a yield of 64.8%. Compared with the standard 1H NMR spectrum, the solid was identified as 2,2'-dihydroxy-5,5'-diadamantyl diphenyl ether (compound L3). 1 H NMR (400 MHz, CDCl3) δ 7.01 (s, 2H, Ph- H ), 6.92 (s, 2H, Ph- H ), 6.72 (d, J = 2.2 Hz, 2H, Ph- H ), 5.74 (s, 2H, O) H ), 2.10 (s, 6H, Ad- H ), 1.80 (s, 12H, Ad- H ), 1.61 (s, 6H, Ad- H ), 1.43 (s, 6H, Ad- H HRMS(EI), m / z: C 32 H 38 O3, Calcd., 470.2821. Found, 470.2823.); where the proton spectrum of compound L3 is as follows: Figure 1 As shown, the mass spectrum of compound L3 is as follows: Figure 2 As shown; (3) Under a nitrogen atmosphere, compound L3 (1 mmol, 470.3 mg) and 40 mL of toluene were weighed into a Schlenk flask and a solution containing compound L3 was prepared; tetraisopropyl titanate (0.5 mmol, 142.1 mg) and 10 mL of toluene were weighed into a Schlenk flask and a solution containing tetraisopropyl titanate was prepared; the solution containing tetraisopropyl titanate was added dropwise to the solution containing compound L3 at -78 °C, and after restoring to 25 °C, the reaction was continued at 60 °C for 24 h. After the reaction was completed, the mixture was allowed to stand, 2 / 3 of the toluene was removed under reduced pressure, and then n-hexane was added dropwise until a solid appeared. The mixture was then recrystallized at -20 °C for 48 h, and after filtration and drying, a dark red solid (complex C3) of 453.2 mg was obtained, with a yield of 46.1%. 1 H NMR (400 MHz, CDCl3) δ 7.97 – 7.91 (m, 4H, Ph- H ), 7.85 (d, J = 9.1 Hz, 4H, Ph- H ), 7.21 – 7.16 (m, 4H, Ph- H ), 1.51 (s, 12H, Ad- H ), 1.41(d, J = 3.9 Hz, 24H, Ad- H ), 1.28 (s, 12H, Ad- H ), 1.18 (d, J = 6.1 Hz, 12H, Ad- H ). 13 C NMR (101 MHz, CDCl3) δ 143.94 (Ph- C ), 137.99 (Ph- C ), 129.17 (Ph- C ), 128.37 (Ph- C ), 125.44 (Ph- C ), 116.34 (Ph- C ), 43.49 (Ad- C ), 40.59 (Ad- C ), 36.86 (Ad- C ), 29.24 (Ad- C ), 21.61 (Ad- C MALDI-TOF-MS (laser 355 nm, frequency 200 Hz, matrix DHB): C 64 H 72O6Ti, Calcd., 984.4808, Found, 984.4831.), where the proton spectrum of complex C3 is as follows: Figure 3 As shown, the carbon spectrum of complex C3 is as follows: Figure 4 As shown.

[0042] Example 2 (1) Under a nitrogen atmosphere, 50 mL of THF, diphenyl ether (10 mmol, 1702 mg), and TMEDA (25 mmol, 2905 mg) were added sequentially to a 100 mL Schlenk flask and mixed. The resulting mixture was placed in a liquid nitrogen acetone bath. Then, n-butyllithium solution (25 mmol, 2.5 mol / L, n-hexane, 10 mL) was added dropwise to the mixture. After restoring to 25 °C, the reaction was continued at 25 °C for 8 h. The resulting product was then placed in a liquid nitrogen acetone bath. B(OMe)3 (40 mmol, 4156 mg) was slowly added dropwise to the resulting product. The temperature was slowly restored to 25 °C, and the reaction was continued at 25 °C for 6 h. Sodium hydroxide aqueous solution (60 mmol, 1 mol / L, 2400 mg) was added dropwise at 25 °C. The product was reacted at 25°C for 1 hour, and then placed in an ice-water bath. Hydrogen peroxide solution (34 wt%, 60 mmol, 6 mL) was slowly added dropwise to the product, and the reaction continued for 5 hours. THF was removed under reduced pressure, and the product was extracted three times with 10 mL of diethyl ether each time to remove the organic phase. The aqueous phases were combined, and 5 mol / L hydrochloric acid was slowly added dropwise to the aqueous phase until no more white precipitate was formed. The obtained white crude product was filtered, and then subjected to silica gel column chromatography (volume ratio of petroleum ether to ethyl acetate was 40:1) using petroleum ether and ethyl acetate as eluents. 1260 mg of a white solid was obtained, with a yield of 62.4%. The result, according to the standard 1H NMR spectrum, was 2,2'-dihydroxydiphenyl ether. 1 H NMR (400 MHz, CDCl3) δ7.05 (d, J = 4.3 Hz, 2H, Ph- H ), 7.04 (d, J = 3.2 Hz, 2H, Ph- H ), 6.85 (d, J = 4.2 Hz, 2H, Ph- H ), 6.83 (d, J = 3.1 Hz, 2H, Ph- H ), 5.98 (s, 2H, -O) H ).); (2) Under a nitrogen atmosphere, 2,2'-dihydroxydiphenyl ether (5 mmol, 1010 mg), anhydrous aluminum chloride (8 mmol, 1058 mg), and 50 mL of dichloromethane were added sequentially to a 100 mL Schlenk flask and mixed. The resulting mixture was then placed in a liquid nitrogen acetone bath, and then slowly added dropwise to the mixture. t Bu-Cl (40 mmol, 3703 mg) was slowly restored to 25 °C and the reaction was continued at 25 °C for 16 h. The pH was then adjusted to 5.5 with a 1 mol / L sodium bicarbonate aqueous solution. The mixture was extracted three times with 10 mL of dichloromethane each time. The organic phases were combined, dried over anhydrous Na₂SO₄, and the solvent was removed under reduced pressure. Silica gel column chromatography (15:1 volume ratio of petroleum ether to ethyl acetate) was performed as eluent to give 1159 mg of a pale yellow solid, with a yield of 73.8%. The control was 2,2'-dihydroxy-5,5'-di-tert-butyl diphenyl ether (compound L6). 1 H NMR (400 MHz, CDCl3) δ 7.05 (d, J = 2.2 Hz, 2H, Ph- H ), 6.99 (s, 2H, Ph- H ), 6.90 (d, J =2.2 Hz, 2H, Ph- H ), 5.68 (s, 2H, O) H ), 1.22 (s, 18H, C(C) H 3)3). 13 C NMR (101 MHz, CDCl3) δ144.38 (Ph- C ), 142.91 (Ph- C ), 120.95 (Ph- C ), 116.24 (Ph- C ), 115.37 (Ph- C ), 115.02 (Ph- C ), 34.38 ( C (CH3)3), 31.40 ( C H3). HRMS(EI), m / z: C 20 H 26 O3, Calcd., 314.1882.Found, 314.1884.); (3) Under a nitrogen atmosphere, compound L6 (1 mmol, 314.2 mg) and 40 mL of toluene were weighed into a Schlenk flask and a solution containing compound L6 was prepared; tetraisopropyl titanate (0.5 mmol, 142.1 mg) and 10 mL of toluene were weighed into a Schlenk flask and a solution containing tetraisopropyl titanate was prepared; the solution containing tetraisopropyl titanate was added dropwise to the solution containing compound L6 at -78 °C, and after restoring to 25 °C, the reaction was continued at 60 °C for 24 h. After the reaction was completed, the mixture was allowed to stand, toluene was removed under reduced pressure, and an equal volume of n-hexane was added dropwise. After stirring, the mixture was allowed to stand for 30 min, the supernatant was filtered by pressure, and the lower solid was dried to obtain 458.9 mg of bright red solid (complex C6), with a yield of 68.3%. 1 H NMR (400 MHz, CDCl3) δ 7.94 (dd, J = 8.9 Hz, 3.2 Hz, 4H, Ph- H ), 7.41 (dd, J = 7.2, 1.8 Hz, 4H, Ph- H ), 7.14 (d, J = 9.0 Hz, 4H, Ph- H ), 1.39(s, 36H, C(C H 3)3). 13 C NMR (101 MHz, CDCl3) δ 144.70 (Ph- C ), 144.33 (Ph- C ), 129.19 (Ph- C ), 128.38 (Ph- C ), 121.45 (Ph- C ), 115.86 (Ph- C ), 34.47 C (CH3)3), 31.55 ( C H3). MALDI-TOF-MS (laser 355 nm, frequency 200 Hz, matrix DHB): C 80 H 80 O4Ti, Calcd., 672.2930, Found, 672.2939.), where the proton spectrum of complex C6 is as follows: Figure 5 As shown, the carbon spectrum of complex C6 is as follows: Figure 6 As shown.

[0043] Example 3 Under a nitrogen atmosphere, 1 mmol (356.1 mg) of thiobis(dichlorophenol) and 40 mL of toluene were weighed into a Schlenk flask and a solution containing compound L6 was prepared. 0.5 mmol (142.1 mg) of tetraisopropyl titanate and 10 mL of toluene were weighed into a Schlenk flask and a solution containing tetraisopropyl titanate was prepared. The solution containing tetraisopropyl titanate was added dropwise to the solution containing compound L6 at -78 °C. After restoring to 25 °C, the reaction was continued at 60 °C for 24 h. After the reaction was complete, the mixture was allowed to stand, toluene was removed under reduced pressure, and 20 mL of n-hexane was added dropwise. After stirring and standing for 30 min, the supernatant was pressure filtered. The lower solid was washed three times with 10 mL of n-hexane each time. The lower solid was then dried to obtain 414.9 mg of an orange-yellow solid (complex C8), with a yield of 54.9%. 1 H NMR (400 MHz, CDCl3) δ 7.36 (d, J = 2.4 Hz, 4H, Ph- H ), 7.24 (d, J = 2.4 Hz, 4H, Ph- H ), where the proton spectrum of complex C8 is as follows: Figure 7 As shown.

[0044] Example 4 (1) Under a nitrogen atmosphere, compound L3 (5 mmol, 2352 mg) and adamantanol (15 mmol, 2285 mg) were added sequentially to a 100 mL Schlenk flask, followed by 50 mL of dichloromethane. The mixture was placed in an ice-water bath, and sulfuric acid (5 mmol, 0.3 mL) was added dropwise. The temperature was slowly restored to 25 °C, and the reaction was continued at 25 °C for 72 h. The pH was then adjusted to 5.5 with a 1 mol / L sodium hydroxide aqueous solution. The mixture was extracted three times with 10 mL of dichloromethane each time. The organic phases were combined, dried over anhydrous Na2SO4, and the solvent was removed under reduced pressure. Silica gel column chromatography was performed using petroleum ether and ethyl acetate as eluents (volume ratio of petroleum ether to ethyl acetate was 20:1). 1834 mg of a grayish-white solid was obtained, with a yield of 60.7%. The control was 2,2'-dihydroxy-3,5,5'-triadamantyl diphenyl ether (compound L9). 1 H NMR (400 MHz, CDCl3) δ 7.04 (d, J = 2.3 Hz, 1H, Ph- H ), 7.00 (t, J = 2.3 Hz, 2H, Ph- H ), 6.77 (d, J = 1.4 Hz, 1H, Ph- H), 6.75 (s, 1H, Ph- H ), 6.00 (s, 1H, O) H ), 5.77 (s, 1H, O) H ), 2.22 – 2.18 (m, 24H, Ad- H ), 2.11 (d, J = 3.2 Hz, 15H, Ad- H ), 1.72 – 1.70 (m, 3H, Ad- H ), 1.44 (s, 3H, Ad- H ). 13 C NMR (101 MHz, CDCl3) δ 146.32 (Ph- C ), 145.76 (Ph- C ), 144.42 (Ph- C ), 144.12 (Ph- C ), 143.63 (Ph- C ), 143.11 (Ph- C ), 143.07 (Ph- C ), 142.69 (Ph- C ), 142.64 (Ph- C ), 137.51 (Ph- C ), 136.89 (Ph- C ), 136.61 (Ph- C ), 43.52 (Ad- C ), 40.57 (Ad- C ), 37.49 (Ad- C ), 37.19 (Ad- C ), 36.86 (Ad- C ), 36.19 (Ad- C ), 29.29 (Ad- C HRMS(EI), m / z: C 42 H 52 O3, Calcd., 604.3916. Found, 604.3918.); where the proton spectrum of compound L9 is as follows: Figure 8 As shown, the carbon spectrum of compound L9 is as follows: Figure 9 As shown, the mass spectrum of compound L9 is as follows: Figure 10 As shown; (2) Under a nitrogen atmosphere, compound L9 (1 mmol, 604.4 mg) and 40 mL of toluene were weighed into a Schlenk flask and a solution containing compound L9 was prepared; tetraisopropyl titanate (0.5 mmol, 142.1 mg) and 10 mL of toluene were weighed into a Schlenk flask and a solution containing tetraisopropyl titanate was prepared; the solution containing tetraisopropyl titanate was added dropwise to the solution containing compound L9 at -78 °C, and after restoring to 25 °C, the reaction was continued at 60 °C for 24 h. After the reaction was completed, the mixture was allowed to stand, 2 / 3 of the toluene was removed under reduced pressure, and n-hexane was slowly added dropwise under stirring until a small amount of solid appeared. The mixture was then placed in a refrigerator for recrystallization. The supernatant was filtered under an ice-water bath, and the lower solid was washed with n-hexane and dried to obtain 634.5 mg of bright yellow powder (complex C9), with a yield of 50.7%. 1 H NMR (400 MHz, CDCl3) δ 7.58 – 7.53 (m, 2H, Ph- H ), 7.48 (s, 2H, Ph- H ), 6.98 (s, 2H, Ph- H ), 6.88 (dd, J = 8.6 Hz, 4.4 Hz, 2H, Ph- H ), 6.79 – 6.74 (m, 2H, Ph- H ), 2.20 (d, J =3.5 Hz, 12H, Ad- H ), 2.11 (d, J = 11.0 Hz, 24H, Ad- H ), 2.06 (s, 12H, Ad- H ), 2.02 (s, 6H, Ad- H ), 1.98 – 1.89 (m, 36H, Ad- H ). 13 C NMR (101 MHz, CDCl3) δ 157.47 (Ph- C ), 157.34 (Ph- C ), 154.93 (Ph- C ), 154.86 (Ph- C ), 150.82 (Ph- C ), 146.26 (Ph- C ), 136.32 (Ph- C ), 129.18 (Ph- C ), 128.38 (Ph- C ), 118.92 (Ph- C), 114.15 (Ph- C ), 112.87 (Ph- C ), 43.84 (Ad- C ), 43.73 (Ad- C ), 40.60 (Ad- C ), 37.03 (Ad- C ), 36.38 (Ad- C ), 29.20 (Ad- C MALDI-TOF-MS (laser 355 nm, frequency 200 Hz, matrix DHB): C 80 H 80 O4Ti, Calcd., 1252.6999, Found, 1252.6922.), where the proton spectrum of complex C9 is as follows: Figure 11 As shown, the carbon spectrum of complex C9 is as follows: Figure 12 As shown, the mass spectrum of complex C9 is as follows. Figure 13 As shown.

[0045] Test case Complexes C3, C6, C8, and C9 obtained in Examples 1-4 were used as catalysts for ethylene polymerization. The specific steps are as follows: 1 μmol of the complex was taken from a glove box and 50 mL of toluene was added to prepare a 1 μmol / mL toluene solution containing the complex. Then, a 300 mL reactor was dried at 100 °C for 6 h and purged three times with ethylene and nitrogen. Next, 30 mL of toluene, 3 mL of sesquiethylaluminum chloride (the molar ratio of sesquiethylaluminum chloride to the complex was 600:1), and 20 mL of toluene were added sequentially to the feeding funnel and placed into the reactor. Then, 5 mL of the toluene solution containing the complex was added to the feeding funnel, and the temperature of the reactor was raised to 80-120 °C (determined according to the target polymerization reaction temperature T in Table 1), and the pressure was adjusted to 2 MPa. The process was kept stable, and after the instantaneous flow rate stabilized at 0, a toluene solution containing the complex was added. The polymerization reaction was carried out for 30 minutes. After polymerization, the ethylene gas was turned off, the temperature was lowered to 40℃, the pressure was released, stirring was stopped, and hydrochloric acid-ethanol solution was slowly added to quench the reaction. The polymer was placed in a beaker and stirred for 6 hours. Toluene and ethanol were removed by filtration, and the polymer was vacuum dried at 60℃ for 10 hours and then weighed. The activity of the polymer was calculated according to A=M / (n×t) (where: A: catalytic activity of the catalyst, kg / (mol·Ti·h); n: amount of catalyst, mol; M: mass of polyethylene obtained, g; t: polymerization reaction time, h). The polymerization reaction temperature, polymer mass, and activity were recorded in Table 1, and the polymer crystallinity was tested by scanning calorimetry (DSC). X c), the melting temperature of the polymer (T) m The crystallization temperature (Tg) of the polymer is shown in Table 1, and the schematic diagram of the DSC test results of complex C3 at 90℃ is shown in Table 1. Figure 14 A schematic diagram of the DSC test results of complex C3 at 100°C is shown below. Figure 15 A schematic diagram of the DSC test results of complex C3 at 110℃ is shown below. Figure 16 A schematic diagram of the DSC test results of complex C3 at 120°C is shown below. Figure 17 Furthermore, the polymer obtained from complex C8 at 100°C was subjected to gel permeation chromatography (GPC) to determine the average molecular weight and molecular weight distribution of the polymer. A schematic diagram of the test results is shown below. Figure 18 .

[0046] Table 1

[0047] As shown in Table 1, the examples using the ether-based metal complexes described in this invention exhibit high reactivity and good thermal stability, with polymerization activity gradually increasing with increasing temperature. Taking C3 as an example, the highest activity (3297 kg / (mol·Ti·h)) is achieved at 100°C. According to the Arrhenius equation, as temperature increases, the number of molecules reaching the activation energy increases, and the rate of molecular motion of activated molecules accelerates, thus increasing polymerization activity. However, as the temperature continues to rise, the activity decreases due to two main reasons: firstly, the solubility of ethylene in toluene decreases at higher temperatures; and secondly, the catalyst is prone to decomposition at high temperatures.

[0048] from Figure 1 and Figure 2 As can be seen, 2,2'-dihydroxy-5,5'-diadamantyl diphenyl ether, namely compound L3 shown in formula (II), was successfully prepared in Example 1, wherein R2 and R4 are both H, R1 and R3 are both adamantyl, and X is O.

[0049] from Figure 3 and Figure 4 As can be seen, the complex C3 shown in formula (I) was successfully prepared in Example 1, wherein M is Ti, R2 and R4 are both H, R1 and R3 are both adamantyl alkyl groups, and X is O.

[0050] from Figure 5 and Figure 6 As can be seen, the complex C6 shown in formula (I) was successfully prepared in Example 2, where M is Ti, R2 and R4 are both H, R1 and R3 are both tert-butyl, and X is O.

[0051] from Figure 7As can be seen, the complex C8 shown in formula (I) was successfully prepared in Example 3, where M is Ti, R1, R2, R3 and R4 are homochlorine, and X is S.

[0052] from Figure 8-12 As can be seen, Example 4 successfully prepared 2,2'-dihydroxy-3,5,5'-triadamantyl diphenyl ether, namely compound L9 shown in formula (II), wherein R4 is H, R1, R2 and R3 are all adamantyl, and X is O.

[0053] from Figure 11-13 As can be seen, in Example 4, the complex C9 shown in formula (I) was successfully prepared, where M is Ti, R4 is H, R1, R2 and R3 are all adamantyl alkyl groups, and X is O.

[0054] Depend on Figure 14 It can be seen that the DSC test result of complex C3 at 90℃ is: T m The temperature was 127.1℃, T g The temperature is 110.5℃, and ΔH m It is 248.9 J / g. X c It was 86.9%; by Figure 15 It can be seen that the DSC test results for complex C3 at 100℃ are: T m The temperature was 126.5℃, T g The temperature is 109.6℃, and the ΔH is... m It is 248.7 J / g. X c It was 84.8%; by Figure 16 It can be seen that the DSC test results of complex C3 at 110℃ are: T m The temperature was 127.1℃, T g The temperature is 111.4℃, and ΔH m It is 224.7 J / g. X c It was 76.7%; by Figure 17 It can be seen that the DSC test results of complex C3 at 120℃ are: T m The temperature was 127.4℃, T g The temperature is 109.5℃, and ΔH m It is 241.1 J / g. X c The value was 82.3%, indicating that the prepared low molecular weight polyethylene had a high melting and crystallization temperature, which in turn indicated that it had a high melting point, high heat resistance, and good crystallinity.

[0055] Figure 18 Polymers prepared using the ether-based metal complexes described in this invention as catalysts exhibit a narrow molecular weight distribution and can also yield low molecular weight polyethylene polymers; wherein, Figure 18In the graph, "dw / dlogM" represents the derivative of the logarithm of the weight distribution with respect to the molecular weight, reflecting the rate of change and distribution of the polymer's mass at a specific molecular weight; "Mw" represents the molecular weight, indicating the statistical average of the polymer's molecular weight distribution; "Ht%" represents the proportion of high molecular weight molecules in the polymer; the vertical axis of the blue line corresponds to "dw / dlogM," representing the signal intensity of each molecular weight, with higher values ​​indicating a higher molecular weight; the vertical axis of the red line corresponds to "Ht%," representing the cumulative integral result, known as the cumulative integral curve. This curve allows direct estimation of the proportion of molecules in any molecular weight range within the total molecules. Figure 18 In the graph, the blue line represents the signal intensity of each molecular weight, with higher values ​​indicating a larger molecular weight. The red line represents the cumulative score, known as the cumulative integral curve. This curve allows direct estimation of the proportion of molecules in any molecular weight range within the total molecular weight.

[0056] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. An ether-based metal complex, characterized in that, Its structural formula is shown in equation (I): Equation (I); R1, R2, R3 and R4 are each independently selected from hydrogen, C1-C10 alkyl groups and halogens; X is selected from either O or S; M is selected from group IVB metals.

2. The ether-based metal complex according to claim 1, characterized in that, R1, R2, R3 and R4 are each independently selected from one of hydrogen, adamantyl, tert-butyl and chlorine; And / or, M is selected from Ti or Zr.

3. The ether-based metal complex according to claim 1 or 2, characterized in that, It is selected from the group consisting of the following coordination compounds: Complex 1: The complex shown in formula (I), wherein M is Ti, R2 and R4 are both H, R1 and R3 are both adamantyl alkyl groups, and X is O; Complex 2: The complex shown in formula (I), wherein M is Ti, R2 and R4 are both H, R1 and R3 are both tert-butyl, and X is O; Complex 3: The complex shown in formula (I), wherein M is Ti, R4 is H, R1, R2 and R3 are all adamantyl alkyl groups, and X is O; Complex 4: The complex shown in formula (I), where M is Ti, R1, R2, R3 and R4 are all chlorine, and X is S.

4. A method for preparing the ether-based metal complex according to any one of claims 1-3, characterized in that, The method includes: complexing the compound shown in formula (II) with a metal salt of M; Formula (II); The definitions of R1, R2, R3, R4 and X are the same as in claim 1; The M metal salt is selected from group IVB metals.

5. The method according to claim 4, characterized in that, The specific process of the method includes: adding a solution containing the metal salt of M dropwise to a solution containing the compound shown in formula (II) at -85 to -75°C, followed by a complexation reaction at 55-65°C.

6. The method according to claim 4 or 5, characterized in that, The molar ratio of the amount of the metal salt M to the compound shown in formula (II) is 1:(2-2.2), wherein the metal salt M is calculated as the metal element M.

7. The method according to any one of claims 4-6, characterized in that, The M metal salt is selected from Ti(O) i Pr)4 and / or Zr(O) i Pr)4.

8. The method according to any one of claims 4-7, characterized in that, In a solution containing the metal salt M, the solvent is selected from at least one of toluene, chloroform, n-heptane, and n-hexane.

9. The method according to any one of claims 4-8, characterized in that, In a solution containing the compound shown in formula (II), the solvent is selected from at least one of toluene, chloroform, n-heptane, and n-hexane.

10. A method for preparing polyethylene, characterized in that, Ethylene is polymerized in the presence of a catalyst containing an ether-metal complex as described in any one of claims 1-3.

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