Star-shaped biphenyl complex as well as preparation method and application thereof

Abstract

The invention discloses an olefin polymerization catalyst. The catalyst has a biphenyl skeleton structure. According to the catalyst, star-shaped biphenyl is introduced to serve as a rigid center, the high temperature resistance of the catalyst is improved, and due to the characteristic that a benzene ring is rotatable in space, molecules can spontaneously adjust steric hindrance of an active center, so that the catalyst has high activity. Meanwhile, amine in acylhydrazone is connected with active center metal, and due to the electron withdrawing effect of carbonyl, the electron cloud density of the active center is more beneficial to improving the high-temperature resistance of the catalyst. The star-shaped biphenyl complex disclosed by the invention has a wide application prospect, and can be used for preparing an ultra-high molecular weight polyolefin product which is high in anti-yellowing performance, wide in molecular weight step and easy to process.

Description

Technical Field

[0001] This invention relates to the field of catalysts, specifically to a "star-shaped" biphenyl complex, its preparation method, and its uses. Background Technology

[0002] Polyolefin elastomers are a pillar industry in the polymer materials sector today. Currently, polyolefin materials and related products possess relatively good performance and are widely used in people's daily lives. In the production process of polyolefin elastomers, the polyolefin catalyst determines the material's performance and cost, playing a crucial role in production. Therefore, accelerating the research of polyolefin catalysts is particularly important at this stage.

[0003] In patent EP0416815B1, DOW invented a class of catalysts with restricted geometry. These catalysts have a high comonomer insertion rate but poor thermal stability and low activity at high temperatures.

[0004] Mitsui's patent EP0874005B1 describes a catalyst based on aryloxyimines that exhibits high activity during olefin polymerization, but its drawback remains poor thermal stability.

[0005] Dow Chemicals disclosed a metallocene catalyst with a restricted geometry (as shown below) in its patent (US5064802) for the random copolymerization of olefins and α-olefins. The catalyst has a high comonomer insertion rate, but poor temperature resistance. The molecular weight of the catalyzed random copolymers of olefins and α-olefins is low, and the processing performance is poor, which cannot meet the production requirements.

[0006]

[0007] Dow reported on the use of group IVB metal catalysts with imine-amine ligands for the copolymerization of ethylene and α-olefins (Organometallics 2011, 30, 251-262). As shown in the figure below, the complexes exhibit isomerization at higher temperatures, resulting in lower activity. Furthermore, the comonomer insertion rate is low, failing to meet industrial requirements.

[0008]

[0009] To address the aforementioned problems in existing technologies, there is a need in this field to further regulate metal catalysts by controlling the type of metal at the catalyst center and the structure of the ligands, thereby obtaining polymeric materials with high temperature resistance, high activity, high molecular weight, and wide molecular weight distribution. Summary of the Invention

[0010] To address the aforementioned technical problems, this invention proposes an olefin polymerization catalyst (metal complex) with a "star-shaped" biphenyl skeleton as its core, its preparation method, and its applications. The catalyst possesses a "star-shaped" biphenyl skeleton structure. By introducing the "star-shaped" biphenyl skeleton as a rigid center, the catalyst's high-temperature resistance is improved. Furthermore, the rotational characteristics of the benzene ring allow the catalyst to self-adjust its active steric hindrance, significantly enhancing its activity. Simultaneously, by introducing an amine from the acylhydrazone to connect with the metal active center, the electron-withdrawing effect of the carbonyl group further optimizes the electron cloud density of the active center, resulting in a catalyst with high polymerization activity. This catalyst can be used to prepare polyolefin products with strong anti-yellowing properties, a wide molecular weight distribution, and ultra-high molecular weight.

[0011] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0012] A star-shaped biphenyl complex, the structure of which is shown in Formula I:

[0013]

[0014] in,

[0015] R1 and R2 are each independently selected from hydrogen, C1-C24 alkyl, and C1-C20 alkoxy; when neither R1 nor R2 is hydrogen, they are the same.

[0016] M is selected from group IVB metals;

[0017] X is independently selected from halogens, C1-C10 alkyl groups, and C7-C15 aralkyl groups.

[0018] According to the complex of the present invention, preferably, in Formula I, R1 and R2 are each independently selected from hydrogen, C1-C10 alkyl, and C1-C18 alkoxy; when neither R1 nor R2 is hydrogen, they are the same; more preferably, in Formula I, R1 and R2 are each independently selected from hydrogen, C1-C4 alkyl, and C1-C14 alkoxy; when neither R1 nor R2 is hydrogen, they are the same; for example, R1 and R2 are each independently selected from hydrogen, methyl, methoxy, and dodecyloxy; when neither R1 nor R2 is hydrogen, they are the same.

[0019] According to the complex of the present invention, M in Formula I is selected from titanium, zirconium or hafnium.

[0020] According to the complex of the present invention, preferably, X is independently selected from halogen, C1-C8 alkyl or C7-C8 arylalkyl, more preferably, X is independently selected from halogen, C1-C6 alkyl or C7-C8 arylalkyl, for example, X is independently selected from methyl, chlorine or benzyl.

[0021] According to the coordination compound of the present invention, some specific structures of Formula I are as follows:

[0022]

[0023]

[0024] The present invention also provides a method for preparing the aforementioned "star-shaped" biphenyl complex.

[0025] A method for preparing a "star-shaped" biphenyl complex includes:

[0026] The ligand compound shown in Formula II undergoes a complexation reaction with the metal salt MX4;

[0027]

[0028] The definitions of R1, R2, M, X, etc. are as described above.

[0029] According to the preparation method of the present invention, the metal salt MX4 is selected from titanium tetrachloride, zirconium tetrachloride, hafnium tetrachloride, tetrabenzyl hafnium, tetra(ethylmethyl)aminozirconium, titanium tetrabromide, zirconium tetrabromide or hafnium tetrabromide.

[0030] According to the preparation method of the present invention, the molar ratio of the ligand compound shown in Formula II to the metal salt MX4 is 1:(3-5).

[0031] According to the preparation method of the present invention, the temperature of the complexation reaction is 20℃~60℃ and the time is 1h~4h.

[0032] According to the preparation method of the present invention, the ligand compound represented by formula II is prepared by the following reaction:

[0033]

[0034] R1 and R2 are defined as above.

[0035] According to the preparation method of the present invention, the preparation steps of the ligand compound represented by Formula II include:

[0036] 1) In a solvent, compound A and hydrogen gas react under the action of a catalyst to form compound B;

[0037] 2) Diketene and compound B react in an organic solvent to produce compound C;

[0038] 3) In a solvent, compound D and hydrogen react with a catalyst to form compound E;

[0039] 4) Compound E is added to sodium nitrite under strong acid conditions and reacts with compound C in a solvent to produce compound F.

[0040] According to the preparation method of the present invention, in the preparation step of the ligand compound shown in Formula II,

[0041] In step 1), the reaction conditions are: reaction temperature 30–80℃, reaction time 1–5h;

[0042] In step 2), the reaction conditions are: reaction temperature 25-60℃, reaction time 2-12h.

[0043] In step 3), the reaction conditions are: reaction temperature 30–80℃, reaction time 1–5 h;

[0044] In step 4), the reaction conditions are: reaction temperature 0–30℃, reaction time 1–5h;

[0045] According to the method for preparing the catalyst of the present invention, in the step of preparing the ligand compound shown in Formula II,

[0046] In step 1), the solvent is one or more of methanol, ethanol, ethylene glycol, and glycerol.

[0047] The catalyst is palladium on carbon with a Pb content of 5-15%;

[0048] In some specific embodiments, compound A is preferably selected from one of nitrobenzene, p-methylnitrobenzene, 3,5-dimethylnitrobenzene, 3,4,5-trimethylnitrobenzene, p-dodecyloxynitrobenzene, 3,5-dococosyloxynitrobenzene, and 3,4,5-tridodecyloxynitrobenzene.

[0049] In step 2), the organic solvent is one or more of benzene, toluene, methanol, and ethanol;

[0050] In step 3), the solvent is one or more of methanol, ethanol, ethylene glycol, and glycerol, and the catalyst is palladium on carbon with a Pb content of 5-15%.

[0051] In step 4), the strong acid is concentrated hydrochloric acid, and the solvent is one or more of water, ethanol, methanol, ethyl acetate, and tetrahydrofuran.

[0052] According to the method for preparing the catalyst of the present invention, in the step of preparing the ligand compound shown in Formula II,

[0053] In step 1), the mass ratio of compound A to palladium on carbon is 1:(0.1–0.5);

[0054] In step 2), the molar ratio of compound B to diketene is 1:(1–1.5).

[0055] In step 3), the mass ratio of compound D to palladium on carbon is 1:(0.1–0.5).

[0056] In step 4), the molar ratio of compound E, strong acid, sodium nitrite, and compound C is 1:(2-5):(2-6):(2-4).

[0057] The present invention further provides a method for preparing polyolefins, the method comprising: polymerizing olefins or α-olefins in a solvent in the presence of the "star-shaped" biphenyl complex and a co-catalyst described in the present invention to prepare polyolefin products.

[0058] According to the method for preparing polyolefins of the present invention, the concentration of the "star-shaped" biphenyl complex in the solvent is 0.1 ppm to 50 ppm.

[0059] According to the method for preparing polyolefins of the present invention, the solvent used in the polymerization reaction is selected from one or more of alkanes, cycloalkanes, and aromatics, preferably toluene, heptane, hexane, Isopar E, and cyclohexane.

[0060] According to the method for preparing polyolefins of the present invention, the polymerization reaction temperature is 10-300°C, preferably 80-250°C; the polymerization reaction pressure is 0.1-20 MPa, preferably 1-8 MPa.

[0061] In the method for preparing polyolefins according to the present invention, the co-catalyst is alkylaluminum.

[0062] According to the method for preparing polyolefins of the present invention, the alkylaluminum is selected from C1-C64. 10 Alkyl aluminum oxane or modified aluminum oxane, preferably tert-butyl aluminum oxane, wherein the molar ratio of metal Al in the alkyl aluminum to metal M in the "star-shaped" biphenyl complex shown in Formula I is Al / M (10-200):1.

[0063] Beneficial effects

[0064] Compared with the prior art, the beneficial effects of the technical solution of the present invention are as follows:

[0065] By introducing a star-shaped biphenyl framework as a rigid center, the high-temperature resistance of the catalyst is improved. Furthermore, the rotational characteristics of the benzene ring allow the catalyst to self-adjust its active steric hindrance, significantly enhancing its activity. This makes it suitable for preparing polyolefin products with strong anti-yellowing properties, a wide molecular weight distribution, and ultra-high molecular weight. The star-shaped biphenyl complex of this invention has broad application prospects. Detailed Implementation

[0066] The present invention will be further illustrated below with specific embodiments. These embodiments are merely illustrative and do not limit the scope of the invention.

[0067] The main materials and reagents used in the following examples are from the following sources:

[0068] Palladium on carbon: AR, Aladdin

[0069] Nitrobenzene: AR, Innochem

[0070] p-Methylnitrobenzene: AR, Innochem

[0071] 3,5-Dimethylnitrobenzene: AR, Innochem

[0072] 3,4,5-Dimethylnitrobenzene: AR, Innochem

[0073] Diketene: AR, Innochem

[0074] Benzene: AR, Aladdin

[0075] Toluene: AR, Aladdin

[0076] Methanol: AR, Aladdin

[0077] Tetrahydrofuran: AR, Innochem

[0078] Ethyl acetate: AR, Aldrich

[0079] Petroleum ether: AR, Aldrich

[0080] Anhydrous sodium sulfate: AR, Innochem

[0081] Silicone: AR, Aladdin

[0082] Hydrochloric acid: AR, Aldrich

[0083] Sodium nitrite: AR, Innochem

[0084] Anhydrous sodium acetate: AR, Innochem

[0085] Urea: AR, Innochem

[0086] Lithium n-methyl: AR, Innochem

[0087] n-Butyllithium: AR, Innochem

[0088] TiCl4: Tokyo Chemical Industry Co., Ltd.

[0089] ZrCl4: Tokyo Chemical Industry Co., Ltd.

[0090] HfCl4: Tokyo Chemical Industry Co., Ltd.

[0091] Tri-pentafluorophenylboron salt: AR, Aladdin

[0092] Phenoxyimide zirconium: AR, Aladdin

[0093] 4,4”-Dinitro-5'-(4-nitrophenyl)-1,1':3',1”-terphenylAR, Aladdin

[0094] Isopar E: ExxonMobil

[0095] tert-Butylaluminoxane (MAO): Albemarle

[0096] Ethylene: 99.9%, Beijing Yanshan Petrochemical Company

[0097] 1-Hexene: 98%, Beijing Yanshan Petrochemical Company.

[0098] The synthetic route for alkoxynitrobenzene intermediate A is as follows:

[0099] Taking p-dodecyloxynitrobenzene as an example

[0100]

[0101] 342 g of compound 3,4,5-trihydroxynitrobenzene was placed in a 5 L reactor, 3 L of acetonitrile and 400 g of potassium hydroxide were added, and after stirring, 1500 g of bromododecane was added. The mixture was reacted at 80 °C for 3 h, and then extracted three times with water. The aqueous phase was released and the organic phase was retained. After the solvent was evaporated, the product was recrystallized from methanol to obtain 1024 g.

[0102] The NMR data of the product are as follows: 1H NMR (CDCl3, 500MHz, TMS) δ 7.83 (s, 2H), 4.24 (t, 6H), 1.76 (m, 6H), 1.31 (m, 54H), 1.31 (m, 9H).

[0103] Unless otherwise specified, all other raw materials and reagents were obtained through commercially available channels.

[0104] Unless otherwise specified, the experimental methods used in the following examples are conventional methods.

[0105] The polymerization activity of the polymers described in the following examples was calculated according to the following formula: Polymer activity = polymer mass / (metal content in catalyst * polymerization time);

[0106] The weight-average molecular weight (Mw) and molecular weight distribution (PDI) of the polymer were obtained by testing with a PL-GPC220 at 160℃ using three PLgel 10μm MIXED-B separation columns in series, with 1,2,4-trichlorobenzene as the solvent.

[0107] The method for calculating the comonomer insertion rate is referenced in (Macromolecules 1999, 32, 3817);

[0108] The terminal double bonds of the polymer were calculated using iodometric titration.

[0109] In all the following examples and comparative examples, the chemical reactions involved were carried out after nitrogen purging.

[0110] Example 1: Preparation of metal complex G1

[0111] The ligand and metal complex G1 were prepared according to the following combined route:

[0112]

[0113] (1) Nitrobenzene (246g, 2mol) and 5% palladium on carbon (25g) were added to ethanol (2L), the magnetic stirrer was turned on, hydrogen gas was introduced to maintain the pressure at 0.5mpa, the temperature was set at 30℃, and the reaction was carried out for 1h. After the reaction was completed, a solid was precipitated after cooling. After standing overnight, the solid was filtered and dried to obtain compound B1 (180g).

[0114] The NMR data for compound B1 are as follows: 1 H NMR(CDCl3,500MHz,TMS)δ7.58(t,2H),6.80(t,2H),6.57(t,1H),6.25(s,2H).

[0115] (2) Diketene (84 g, 1 mol) and compound B1 (93.1 g, 1 mol) were dissolved in benzene (500 mL). The magnetic stirrer was turned on to completely dissolve the reactants in the solvent benzene. The reaction was carried out at room temperature for 12 h. After the reaction was completed, the product was washed, extracted with ethyl acetate, dried, filtered, and concentrated under reduced pressure to obtain crude compound C1. The product was purified by silica gel column chromatography (petroleum ether: ethyl acetate = 20:1 (v / v)) to obtain compound C1 (176 g).

[0116] The NMR data for compound C1 are as follows: 1 H NMR(CDCl3,500MHz,TMS)δ7.58(t,2H),6.80(t,2H),6.57(t,1H),6.2(s,1H),3.57(s,2H),2.25(s,3H)

[0117] (3) 4,4”-dinitro-5'-(4-nitrophenyl)-1,1':3',1”-terphenyl (882g, 2mol) and 5% palladium on carbon (88g) were added to ethanol (2L), the magnetic stirrer was turned on, hydrogen gas was introduced to maintain the pressure at 0.5mpa, the temperature was set at 80℃, and the reaction was carried out for 1h. After the reaction was completed, the solid precipitated after cooling. After standing overnight, the solid was filtered and dried to obtain compound E (650g).

[0118] The NMR data for compound E are as follows: 1 H NMR(CDCl3,500MHz,TMS)δ7.58(s,3H),7.50(d,6H),6.57(d,6H),6.2(s,6H)

[0119] (4) Add compound E (35g, 0.1mol) and concentrated hydrochloric acid (25mL, 0.3mol) to water, stir, and continue to add sodium nitrite (13.8g, 0.2mol) to the reaction flask under ice bath conditions of 0℃, stir for 30min, keep the reaction bath temperature below 10℃, add anhydrous sodium acetate to adjust the pH to about 6, filter the reaction mixture, wash the reaction mixture with water to obtain an aqueous solution of diazonium salt, add compound C1 (53g, 0.3mol) to the diazonium solution, stir at 20℃, react for 2h, wash with water, extract with ethyl acetate, dry, filter, concentrate under reduced pressure to obtain crude compound F1, and purify by silica gel column chromatography (petroleum ether: ethyl acetate = 12:1 (v / v)) to obtain compound F1 (80g).

[0120] The NMR data for compound F1 are as follows: 1 H NMR(CDCl3,500MHz,TMS)δ10.1(s,3H),7.66(s,3H),7.61(d,6H),7.58(d,6H),7.48(d,6H),7.19(t,6H),6.57(d,6H),2.24(s,9H)

[0121] (5) Perform anhydrous and oxygen-free operation in a glove box. Place compound F1 (9.1g, 0.01mol) in a reaction flask, add toluene (100mL) and stir to dissolve. Add ZrCl4 (7g, 0.03mol) and react for 3h. After the reaction is complete, filter, dry the filtrate, add n-hexane to wash, and filter to obtain a solid product, which is denoted as metal complex G1.

[0122]

[0123] Example 2: Preparation of metal complex G2

[0124] The ligand and metal complex G2 were prepared according to the following combined route:

[0125]

[0126] (1) 3,5-Dimethylnitrobenzene (302g, 2mol) and 15% palladium on carbon (150g) were added to ethanol (2L), the magnetic stirrer was turned on, hydrogen gas was introduced to maintain the pressure at 0.5mpa, the temperature was set at 80℃, and the reaction was carried out for 1h. After the reaction was completed, a solid was precipitated after cooling. After standing overnight, the solid was filtered and dried to obtain compound B2 (200g).

[0127] The NMR data for compound B1 are as follows: 1 H NMR(CDCl3,500MHz,TMS)δ7.58(t,2H),6.80(t,2H),6.57(t,1H),2.25(s,6H).

[0128] (2) Diketene (126g, 1.5mol) and compound B2 (121g, 1mol) were dissolved in benzene (500mL). The magnetic stirrer was turned on to completely dissolve the reactants in benzene. The reaction was carried out at room temperature for 12h. After the reaction was completed, the mixture was washed, extracted with ethyl acetate, dried, filtered, and concentrated under reduced pressure to obtain crude compound C2. The crude compound C2 was purified by silica gel column chromatography (petroleum ether: ethyl acetate = 20:1 (v / v)) to obtain compound C2 (196g).

[0129] The NMR data for compound C2 are as follows: 1 H NMR(CDCl3,500MHz,TMS)δ7.58(t,2H),6.57(t,1H),6.2(s,1H),3.57(s,2H),2.25(m,9H)

[0130] (3) Add compound E (35g, 0.1mol) and concentrated hydrochloric acid (41mL, 0.5mol) to water, stir, and continue to add sodium nitrite (41.4g, 0.6mol) to the reaction flask under ice bath conditions of 0℃, stir for 30min, keep the reaction bath temperature below 10℃, add anhydrous sodium acetate to adjust the pH to about 6, filter the reaction mixture, wash the reaction mixture with water to obtain an aqueous solution of diazonium salt, add compound C2 (82g, 0.4mol) to the diazonium solution, stir at 20℃, react for 2h, wash with water, extract with ethyl acetate, dry, filter, concentrate under reduced pressure to obtain crude compound F2, and purify by silica gel column chromatography (petroleum ether: ethyl acetate = 12:1 (v / v)) to obtain compound F2 (81g).

[0131] The NMR data for compound F2 are as follows: 1H NMR(CDCl3,500MHz,TMS)δ10.1(s,3H),7.66(s,3H),7.61(d,6H),7.58(d,6H),7.19(t,3H),6.57(d,6H),2.24(s,27H)

[0132] (4) Perform anhydrous and oxygen-free operation in a glove box. Place compound F2 (9.9g, 0.01mol) in a reaction flask, add toluene (100mL) and stir to dissolve. Add HfCl4 (9.6g, 0.03mol) and react for 3h. After the reaction is complete, filter, dry the filtrate, add n-hexane to wash, and filter to obtain a solid product, which is denoted as metal complex G2.

[0133]

[0134] Example 3: Preparation of metal complex G3

[0135] The ligand and metal complex G3 were prepared according to the following combined route:

[0136]

[0137] (1) 3,4,5-trimethylnitrobenzene (330g, 2mol) and 10% palladium on carbon (33g) were added to ethanol (2L), the magnetic stirrer was turned on, hydrogen gas was introduced to maintain the pressure at 0.5mpa, the temperature was set at 80℃, and the reaction was carried out for 1h. After the reaction was completed, a solid was precipitated after cooling. After standing overnight, the solid was filtered and dried to obtain compound B3 (200g).

[0138] The NMR data for compound B3 are as follows: 1 H NMR(CDCl3,500MHz,TMS)δ7.58(t,2H),6.80(t,2H),6.57(t,1H),2.25(s,9H).

[0139] (2) Diketene (126g, 1.5mol) and compound B3 (135g, 1mol) were dissolved in benzene (500mL). The magnetic stirrer was turned on to completely dissolve the reactants in the benzene. The reaction was carried out at room temperature for 12h. After the reaction was completed, the mixture was washed, extracted with ethyl acetate, dried, filtered, and concentrated under reduced pressure to obtain crude compound C3. The crude compound C3 was purified by silica gel column chromatography (petroleum ether: ethyl acetate = 20:1 (v / v)) to obtain compound C3 (180g).

[0140] The NMR data for compound C3 are as follows: 1H NMR(CDCl3,500MHz,TMS)δ7.58(t,2H),6.57(t,1H),6.2(s,1H),3.57(s,2H),2.25(m,12H)

[0141] (3) Add compound E (35g, 0.1mol) and concentrated hydrochloric acid (42mL, 0.5mol) to water, stir, and continue to add sodium nitrite (27.6g, 0.4mol) to the reaction flask under ice bath conditions of 0℃, stir for 30min, keep the reaction bath temperature below 10℃, add anhydrous sodium acetate to adjust the pH to about 6, filter the reaction mixture, wash the reaction mixture with water to obtain an aqueous solution of diazonium salt, add compound C3 (65.7g, 0.3mol) to the diazonium solution, stir at 20℃, react for 2h, wash with water, extract with ethyl acetate, dry, filter, concentrate under reduced pressure to obtain crude compound F3, and purify by silica gel column chromatography (petroleum ether: ethyl acetate = 12:1 (v / v)) to obtain compound F3 (98g).

[0142] The NMR data for compound F3 are as follows: 1 H NMR(CDCl3,500MHz,TMS)δ10.1(s,3H),7.66(s,3H),7.61(d,6H),7.58(d,6H),7.19(t,3H),6.57(d,6H),2.24(s,36H)

[0143] (4) Perform anhydrous and oxygen-free operation in a glove box. Place compound F3 (10g, 0.01mol) in a reaction flask, add toluene (100mL) and stir to dissolve. Add TiCl4 (6g, 0.03mol) and react for 3h. After the reaction is complete, filter, dry the filtrate, add n-hexane to wash, and filter to obtain a solid product, which is denoted as metal complex G3.

[0144]

[0145] Example 4: Preparation of metal complex G4

[0146] The ligand and metal complex G4 were prepared according to the following combined route:

[0147]

[0148] (1) 274 g, 2 mol of p-methylnitrobenzene and 27 g of 10% palladium on carbon were added to ethanol (2 L), the magnetic stirrer was turned on, hydrogen gas was introduced to maintain the pressure at 0.5 MPa, the temperature was set at 80 °C, and the reaction was carried out for 1 h. After the reaction was completed, a solid was precipitated after cooling. After standing overnight, the solid was filtered and dried to obtain compound B4 (180 g).

[0149] The NMR data for compound B4 are as follows: 1 H NMR(CDCl3,500MHz,TMS)δ7.58(t,2H),6.80(t,2H),6.57(t,2H),2.25(s,3H).

[0150] (2) Diketene (126g, 1.5mol) and compound B4 (107g, 1mol) were dissolved in benzene (500mL). The magnetic stirrer was turned on to completely dissolve the reactants in the benzene. The reaction was carried out at room temperature for 12h. After the reaction was completed, the mixture was washed, extracted with ethyl acetate, dried, filtered, and concentrated under reduced pressure to obtain crude compound C4. The crude compound C4 was purified by silica gel column chromatography (petroleum ether: ethyl acetate = 20:1 (v / v)) to obtain compound C4 (180g).

[0151] The NMR data for compound C4 are as follows: 1 H NMR(CDCl3,500MHz,TMS)δ7.58(t,2H),6.57(t,1H),6.2(s,2H),3.57(s,2H),2.25(m,6H)

[0152] (3) Add compound E (35g, 0.1mol) and concentrated hydrochloric acid (42mL, 0.5mol) to water, stir, and continue to add sodium nitrite (27.6g, 0.4mol) to the reaction flask under ice bath conditions of 0℃, stir for 30min, keep the reaction bath temperature below 10℃, add anhydrous sodium acetate to adjust the pH to about 6, filter the reaction mixture, wash the reaction mixture with water to obtain an aqueous solution of diazonium salt, add compound C4 (57g, 0.3mol) to the diazonium solution, stir at 20℃, react for 2h, wash with water, extract with ethyl acetate, dry, filter, concentrate under reduced pressure to obtain crude compound F4, and purify by silica gel column chromatography (petroleum ether: ethyl acetate = 12:1 (v / v)) to obtain compound F4 (60g).

[0153] The NMR data for compound F4 are as follows: 1 H NMR(CDCl3,500MHz,TMS)δ10.1(s,3H),7.66(s,3H),7.61(d,6H),7.58(d,6H),7.19(t,3H),6.57(d,6H),2.24(s,24H)

[0154] (4) Perform anhydrous and oxygen-free operation in a glove box. Place compound F4 (9.5g, 0.01mol) in a reaction flask, add toluene (100mL) and stir to dissolve. Add TiCl4 (5.6g, 0.03mol) and react for 3h. After the reaction is complete, filter, dry the filtrate, add n-hexane to wash, and filter to obtain a solid product, which is denoted as metal complex G4.

[0155]

[0156] Example: Preparation of metal complex G5

[0157] The ligand and metal complex G5 were prepared according to the following combined route:

[0158]

[0159] (1) Add 307g, 1mol of A5 and 30g of 10% palladium on carbon to ethanol (2L), turn on magnetic stirring, introduce hydrogen to maintain pressure of 0.5mpa, set temperature of 80℃, react for 1h, after the reaction is completed, cool and solid precipitates, after standing overnight, filter and dry to obtain compound B5 (270g).

[0160] The NMR data for compound B5 are as follows: 1 H NMR(CDCl3,500MHz,TMS)δ7.58(t,2H),6.80(t,2H),6.57(t,2H),2.25(m,25H).

[0161] (2) Diketene (63g, 0.75mol) and compound B5 (138g, 0.5mol) were dissolved in benzene (500mL). The magnetic stirrer was turned on to completely dissolve the reactants in the benzene. The reaction was carried out at room temperature for 12h. After the reaction was completed, the mixture was washed, extracted with ethyl acetate, dried, filtered, and concentrated under reduced pressure to obtain crude compound C5. The crude compound C5 was purified by silica gel column chromatography (petroleum ether: ethyl acetate = 20:1 (v / v)) to obtain compound C5 (160g).

[0162] The NMR data for compound C5 are as follows: 1 H NMR(CDCl3,500MHz,TMS)δ7.58(t,2H),6.57(t,1H),6.2(s,2H),3.57(s,2H),2.25(m,28H)

[0163] (3) Add compound E (35g, 0.1mol) and concentrated hydrochloric acid (42mL, 0.5mol) to water, stir, and continue to add sodium nitrite (27.6g, 0.4mol) to the reaction flask under ice bath conditions of 0℃, stir for 30min, keep the reaction bath temperature below 10℃, add anhydrous sodium acetate to adjust the pH to about 6, filter the reaction mixture, wash the reaction mixture with water to obtain an aqueous solution of diazonium salt, add compound C5 (108g, 0.3mol) to the diazonium solution, stir at 20℃, react for 2h, wash with water, extract with ethyl acetate, dry, filter, concentrate under reduced pressure to obtain crude compound F5, and purify by silica gel column chromatography (petroleum ether: ethyl acetate = 12:1 (v / v)) to obtain compound F5 (73g).

[0164] The NMR data for compound F5 are as follows: 1 H NMR(CDCl3,500MHz,TMS)δ10.1(s,3H),7.66(s,3H),7.61(d,6H),7.58(d,6H),7.19(t,3H),6.57(d,6H),2.24(s,90H)

[0165] (4) Perform anhydrous and oxygen-free operation in a glove box. Place compound F5 (14g, 0.01mol) in a reaction flask, add toluene (100mL) and stir to dissolve. Add tetramethylzirconium (4.5g, 0.03mol) and react for 3h. After the reaction is complete, filter, dry the filtrate, add n-hexane to wash, and filter to obtain a solid product, which is denoted as metal complex G5.

[0166]

[0167] Example: Preparation of metal complex G6

[0168] The ligand and metal complex G6 were prepared according to the following combined route:

[0169]

[0170] (1) Add 507 g (1 mol) of A6 and 50 g of 10% palladium on carbon to ethanol (2 L), turn on magnetic stirring, introduce hydrogen to maintain pressure of 0.5 MPa, set temperature of 80 °C, react for 1 h, after the reaction is completed, cool and solid precipitates out, stand overnight and filter and dry to obtain compound B6 (400 g).

[0171] The NMR data for compound B6 are as follows: 1H NMR(CDCl3,500MHz,TMS)δ6.12(t,2H),5.80(t,2H),4.07(m,6H),1.75(m,6H),1.45-1.26(m,30H),0.85(m,9H).

[0172] (2) Diketene (63g, 0.75mol) and compound B6 (236g, 0.5mol) were dissolved in benzene (500mL). The magnetic stirrer was turned on to completely dissolve the reactants in the benzene. The reaction was carried out at room temperature for 12h. After the reaction was completed, the mixture was washed, extracted with ethyl acetate, dried, filtered, and concentrated under reduced pressure to obtain crude compound C6. The crude compound C6 was purified by silica gel column chromatography (petroleum ether: ethyl acetate = 20:1 (v / v)) to obtain compound C6 (160g).

[0173] The NMR data for compound C6 are as follows: 1 H NMR(CDCl3,500MHz,TMS)δ7.58(t,2H),6.57(t,2H),6.2(s,1H),3.57(s,2H),4.07(m,6H),1.75(m,6H),1.45-1.26(m,30H),0.85(m,9H)

[0174] (3) Add compound E (35g, 0.1mol) and concentrated hydrochloric acid (42mL, 0.5mol) to water, stir, and continue to add sodium nitrite (27.6g, 0.4mol) to the reaction flask under ice bath conditions of 0℃, stir for 30min, keep the reaction bath temperature below 10℃, add anhydrous sodium acetate to adjust the pH to about 6, filter the reaction mixture, wash the reaction mixture with water to obtain an aqueous solution of diazonium salt, add compound C6 (168g, 0.3mol) to the diazonium solution, stir at 20℃, react for 2h, wash with water, extract with ethyl acetate, dry, filter, concentrate under reduced pressure to obtain crude compound F6, and purify by silica gel column chromatography (petroleum ether: ethyl acetate = 12:1 (v / v)) to obtain compound F6 (73g).

[0175] The NMR data for compound F6 are as follows: 1 H NMR(CDCl3,500MHz,TMS)δ10.1(s,3H),7.66(s,3H),7.61(d,6H),7.58(d,6H),7.19 (t,6H),6.57(d,12H),4.07(m,18H),1.75(m,18H),1.45-1.26(m,90H),0.85(m,27H)

[0176] (4) Perform anhydrous and oxygen-free operation in a glove box. Place compound F6 (21g, 0.01mol) in a reaction flask, add toluene (100mL) and stir to dissolve. Add tetrabenzylzirconium (13.7g, 0.03mol) and react for 3h. After the reaction is complete, filter, dry the filtrate, add n-hexane to wash, and filter to obtain a solid product, which is denoted as metal complex G6.

[0177]

[0178] Example: Preparation of metal complex G7

[0179] The ligand and metal complex G7 were prepared according to the following combined route:

[0180]

[0181] (1) Add 2L of ethanol to A7 (843g, 1mol) and 10% palladium on carbon (80g), turn on magnetic stirring, introduce hydrogen to maintain pressure of 0.5mpa, set temperature of 80℃, react for 1h, after the reaction is completed, cool and solid precipitates, after standing overnight, filter and dry to obtain compound B7 (700g).

[0182] (2) Diketene (63g, 0.75mol) and compound B7 (405g, 0.5mol) were dissolved in benzene (500mL). The magnetic stirrer was turned on to completely dissolve the reactants in the benzene. The reaction was carried out at room temperature for 12h. After the reaction was completed, the mixture was washed, extracted with ethyl acetate, dried, filtered, and concentrated under reduced pressure to obtain crude compound C7. The crude compound C7 was purified by silica gel column chromatography (petroleum ether: ethyl acetate = 20:1 (v / v)) to obtain compound C7 (400g).

[0183] (3) Add compound E (35g, 0.1mol) and concentrated hydrochloric acid (42mL, 0.5mol) to water, stir, and continue to add sodium nitrite (27.6g, 0.4mol) to the reaction flask under ice bath conditions of 0℃, stir for 30min, keep the reaction bath temperature below 10℃, add anhydrous sodium acetate to adjust the pH to about 6, filter the reaction mixture, wash the reaction mixture with water to obtain an aqueous solution of diazonium salt, add compound C7 (270g, 0.3mol) to the diazonium solution, stir at 20℃, react for 2h, wash with water, extract with ethyl acetate, dry, filter, concentrate under reduced pressure to obtain crude compound F7, and purify by silica gel column chromatography (petroleum ether: ethyl acetate = 12:1 (v / v)) to obtain compound F7 (280g).

[0184] (4) Perform anhydrous and oxygen-free operation in a glove box. Place compound F7 (30g, 0.01mol) in a reaction flask, add toluene (100mL) and stir, add zirconium tetrachloride (6.9g, 0.03mol), react for 3h. After the reaction is complete, filter, dry the filtrate, add n-hexane to wash, filter to obtain solid product, which is denoted as metal complex G7.

[0185]

[0186] Comparative Example 1: Preparation of Metal Complex G8

[0187] Catalyst G8, as shown in the following formula, was prepared using the method of Example 1 of patent CN1408731A.

[0188]

[0189] Comparative Example 2: Preparation of Metal Complex G9

[0190] Catalyst G9, as shown in the following formula, was prepared using the method of Example 1 of patent CN113880977B.

[0191]

[0192] Comparative Example 3: Preparation of Metal Complex G10

[0193] The catalyst G10, as shown in Example 1 of patent CN116444579A, was prepared using the method described in the following formula.

[0194]

[0195] Preparation Example: Preparation of Polyolefins

[0196] Using the metal complexes prepared in Examples 1-7 and Comparative Examples 1-3 as the main catalysts, ethylene / 1-hexene copolymerization was carried out according to the following methods and the raw materials and parameters shown in Table 1 to prepare the corresponding polyolefin products:

[0197] A high-pressure reactor containing an ampoule of the main catalyst (1 μmol) was set at 150°C and dried for 3 hours. Vacuum was then applied and the temperature gradually decreased to 25°C. 350 mL of Isopar E, 100 mL of 1-hexene, and tert-butylaluminoxane were added sequentially. The molar ratio of tert-butylaluminoxane to the main catalyst metal element is denoted as Al / M. The amounts of tert-butylaluminoxane added are shown in Table 1. The temperature was raised to 80-250°C, and ethylene monomer was introduced at 1-8 MPa. The ampoule was then broken to initiate the polymerization reaction. Throughout the polymerization, the stirring rate, polymerization temperature, and ethylene pressure remained constant. The reaction time was 5 minutes. After the reaction, the gas in the reactor was vented, the reaction liquid was neutralized, and the polymer precipitate was obtained. This precipitate was washed several times and dried to obtain the polyolefin product.

[0198] Table 1. Reaction conditions for each embodiment and comparative example.

[0199]

[0200] Test Example: Performance Testing of Polyolefins

[0201] The polyolefin products prepared in each embodiment and comparative example were subjected to the performance tests shown in Table 2 below, and the results are as follows:

[0202] Table 2 Performance Test Results

[0203]

[0204] The above examples and comparative data show that the catalyst of the present invention has excellent catalytic performance. When applied to the copolymerization of olefins / 1-hexene, it still maintains high polymerization activity at high temperatures. The polyolefin products prepared by the catalyst of the present invention have excellent polymerization activity, anti-yellowing properties, wide molecular weight distribution, and ultra-high molecular weight.

[0205] The above description is only a preferred embodiment of the present invention. It should be noted that those skilled in the art can make several improvements and additions without departing from the method of the present invention, and these improvements and additions should also be considered within the scope of protection of the present invention.

Claims

1. A "star-shaped" biphenyl complex, the structure of which is shown in Formula I: in, R1 and R2 are each independently selected from hydrogen, C1-C24 alkyl, and C1-C20 alkoxy; when neither R1 nor R2 is hydrogen, they are the same. M is selected from group IVB metals; X is independently selected from halogens, C1-C10 alkyl groups, and C7-C15 arylalkyl groups; Preferably, in Formula I, R1 and R2 are each independently selected from hydrogen, C1-C10 alkyl, and C1-C18 alkoxy; more preferably, in Formula I, R1 and R2 are each independently selected from hydrogen, C1-C4 alkyl, and C1-C14 alkoxy; for example, R1 and R2 are each independently selected from hydrogen, methyl, methoxy, and dodecyloxy; preferably, in Formula I, M is selected from titanium, zirconium, or hafnium. Preferably, in Formula I, X is independently selected from halogen, C1-C8 alkyl or C7-C8 arylalkyl, more preferably, X is independently selected from halogen, C1-C6 alkyl or C7-C8 arylalkyl, for example, X is independently selected from methyl, chlorine or benzyl. Preferably, the structure of the complex shown in Formula I is as follows:

2. The method for preparing the complex according to claim 1, comprising: The ligand compound shown in Formula II undergoes a complexation reaction with the metal salt MX4; Preferably, the metal salt MX4 is selected from titanium tetrachloride, zirconium tetrachloride, hafnium tetrachloride, tetrabenzyl hafnium, titanium tetrabromide, zirconium tetrabromide or hafnium tetrabromide.

3. The preparation method according to claim 2, wherein, The molar ratio of the ligand compound shown in Formula II to the metal salt MX4 is 1:(3-5); Preferably, the temperature of the complexation reaction is 20℃~60℃ and the time is 1h~4h.

4. The preparation method according to any one of claims 2 to 3, wherein, The preparation steps of the ligand compound shown in Formula II include: 1) In a solvent, compound A and hydrogen gas react under the action of a catalyst to form compound B; 2) Diketene and compound B react in an organic solvent to produce compound C; 3) In a solvent, compound D and hydrogen react with a catalyst to form compound E; 4) Compound E is added to sodium nitrite under strong acid conditions and reacts with compound C in a solvent to produce compound F; 5. The preparation method according to claim 4, wherein, In step 1), the reaction conditions are: reaction temperature 30–80℃, reaction time 1–5 h; The catalyst is palladium on carbon with a Pb content of 5-15%; Preferably, the mass ratio of compound A to palladium on carbon is 1:(0.1 to 0.5).

6. The preparation method according to claim 4, wherein, In step 2), the reaction conditions are: reaction temperature 25–60℃, reaction time 2–12 h; The molar ratio of compound B to diketene is 1:(1 to 1.5).

7. The preparation method according to claim 4, wherein, In step 3), the reaction conditions are: reaction temperature 30-80℃, reaction time 1-5h; the catalyst is palladium on carbon with a Pb content of 5-15%. Preferably, the mass ratio of compound D to palladium on carbon is 1:(0.1 to 0.5).

8. The preparation method according to claim 4, wherein, In step 4), the reaction conditions are: reaction temperature 0–30℃, reaction time 1–5h; The strong acid is concentrated hydrochloric acid; Preferably, the molar ratio of compound E, strong acid, sodium nitrite, and compound C is 1:(2-5):(2-6):(2-4).

9. A method for preparing a polyolefin, the method comprising: Polyolefin products are prepared by polymerizing olefins or α-olefins in a solvent in the presence of the complex and co-catalyst described in claim 1. Preferably, the concentration of the complex in the solvent is 0.1 ppm to 50 ppm.

10. The preparation method according to claim 9, wherein, The polymerization reaction temperature is 10–300℃; the pressure is 0.1–20 MPa, preferably 1–8 MPa; The co-catalyst is an alkylaluminum selected from C1-C4. 10 Alkyl aluminum oxane or modified aluminum oxane, preferably tert-butyl aluminum oxane, wherein the molar ratio of metal Al in the alkyl aluminum to metal M in the catalyst shown in Formula I is Al / M = (10-200):1.

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