Nitrogen-oxygen chelating transition metal complex catalyst as well as preparation method and application thereof

Abstract

The invention discloses a nitrogen-oxygen chelated transition metal complex catalyst as well as a preparation method and application thereof, and belongs to the field of olefin polymerization catalysts. The nitrogen-oxygen chelated transition metal complex catalyst has a structure shown in a formula (I), M is selected from IVB group transition metal atoms, Y is selected from silicon atoms, carbon atoms, phosphorus atoms and the like, an oxygen-containing functional group is additionally introduced into a ligand of the catalyst to be coordinated with a central atom titanium, and a chelated transition metal complex is formed. In olefin polymerization, Ti active center cations are stably coordinated with oxygen, the inactivation of the active center can be effectively retarded, and the activity maintenance time can reach more than 1 hour. The catalyst can be used for copolymerization of ethylene and alpha-olefin with more than C8. # imgabs0 #

Description

Technical Field

[0001] The invention relates to the field of olefin polymerization catalysts, and in particular to a nitrogen-oxygen chelated transition metal complex catalyst and a preparation method and application thereof. Background Art

[0002] Polyolefin elastomer (POE for short) is a type of thermoplastic elastic material with a saturated main chain formed by the polymerization of ethylene and α-olefins or cycloolefins. It has low density, narrow molecular weight distribution, excellent elasticity, wear resistance, mechanical properties and processing properties. It is usually prepared by solution polymerization using a single active center catalyst. POE is widely used in automotive toughening materials, photovoltaic cells, footwear materials and medical fields. In order to make these polyolefin materials have excellent properties, the research and development of the polymerization catalyst structure required to prepare these materials is crucial. However, the research on the catalyst system for producing POE is relatively lagging behind.

[0003] Metallocene catalysts are the most widely used catalysts for the production of POE. In the early 1990s, the industrial application of metallocene catalysts laid the foundation for the development of polyolefin elastomers. The structure of the constrained geometry metallocene catalyst is shown in Formula 1. A single metallocene ring, such as cyclopentadienyl (Cp), is connected to another ligand through a bridge group and coordinated with the metal center at the same time, limiting the relative rotation between the metal center and the metallocene ring. It is a bridged single metallocene structure. In 1993, Dow Chemical developed POE products based on a high-temperature solution polymerization process using a constrained geometry metallocene catalyst (CGC). It has the advantages of a single active center, excellent copolymerization ability, and a simple synthetic route, and its application is very mature.

[0004]

[0005] When used alone, CGC catalyst does not have catalytic olefin polymerization activity. It needs to be activated with an additive (methylaluminoxane MAO, organic borane or borate) to convert the CGC catalyst into a cationic alkyl titanium active center, and then catalyze olefin polymerization by coordination insertion with olefins. Among them, the cationic alkyl titanium active center has a strong Lewis acidity and is easy to combine with the weakly basic organic borane and solvent in the polymerization system or dimerize between active centers, resulting in catalyst deactivation. Generally, the activity of the CGC catalyst activated by the additive in a high-temperature solution polymerization reaction is maintained for less than 10 minutes.

[0006] The catalyst with patent publication number CN116284514A uses alkyl metal compounds and organic borate ammonium additives to pre-activate the CGC catalyst. The activated ammonium cation is converted into an organic amine, which coordinates with the Ti active center cation to stabilize the catalyst, allowing the activated catalyst to be stored for up to 40 days in an inert atmosphere at room temperature. However, in the high-temperature reaction of this catalyst, the coordination of amine and Ti is prone to dissociation and regeneration of unstable low-coordination number active centers. Therefore, the stability of the catalyst in the high-temperature polymerization process has not been significantly improved.

[0007] The reaction mechanism is as follows:

[0008] Summary of the invention

[0009] The purpose of the present invention is to overcome the steps of the prior art and provide a nitrogen-oxygen chelated transition metal complex catalyst and its preparation method and application. The catalyst is based on the CGC catalyst, and an oxygen-containing functional group is additionally introduced into the ligand to coordinate with the central atom titanium to form a chelated transition metal complex. In olefin polymerization, the Ti active center cation is stably coordinated with oxygen, which can effectively slow down the deactivation of the active center, and the activity can be maintained for more than 1 hour. It can be used for high-temperature solution copolymerization of ethylene and α-olefins above C8.

[0010] The present invention provides a nitrogen-oxygen chelated transition metal complex having the following structure (I):

[0011]

[0012] in:

[0013] R 1 ,R 2 ,R 3 ,R 4 Selected from hydrogen, C1-C 18 Alkyl or aryl, wherein R 1 ,R 2 ,R 3 ,R 4 The groups can be the same or different from each other, and adjacent groups can form bonds or rings with each other;

[0014] R 5 Selected from hydrogen, C1-C 18 Alkyl or aryl, C1-C 18 Alkyl or aryl substituted silicon, C1-C 18 an alkyl or aryl substituted phosphino group;

[0015] R 6 ,R 7 Selected from hydrogen, C1-C18 Alkyl groups or aryl groups may be the same or different from each other, and may form a bond or a ring with each other;

[0016] R is selected from hydrogen, C1-C 18 Alkyl or aryl groups, the number of which is determined by the valence of Y, can be the same or different, and adjacent groups can form bonds or rings with each other;

[0017] M is selected from a transition metal atom of Group IVB;

[0018] X 1 ,X 2 It is a group selected from halogen atoms, hydrogen atoms, C1-C5 hydrocarbon groups and alkoxy groups, carboxylate groups, fatty amine groups, aromatic amine groups, fatty phosphine groups, aromatic phosphine groups, alkylthio groups, borane, borate esters, alkyl aluminum, silane-substituted C1-C5 hydrocarbon groups, etc.;

[0019] Y is selected from silicon, carbon, phosphorus and other atoms;

[0020] n=0,1,2,3,4,5.

[0021] In order to achieve the above object, the present invention also provides a method for preparing a nitrogen-oxygen chelated transition metal complex, which comprises the following steps:

[0022] Step 1: 1, w-amino alcohol With halogenated hydrocarbon, halogenated silane or halogenated phosphine (R 5 -X) (X is selected from a halogen atom) in the presence of a base to obtain an intermediate represented by formula (II);

[0023]

[0024] Step 2: Under an inert gas atmosphere, the intermediate represented by formula (II) is reacted with a chloride containing a cyclopentadienyl ring and a bridging heteroatom. Reaction to generate the ligand shown in formula (III);

[0025]

[0026] Step 3: Under an inert gas atmosphere, the ligand represented by formula (III) is mixed with an organic lithium reagent at low temperature, and then the temperature is raised to room temperature to react to prepare an organic lithium intermediate represented by formula (IV);

[0027]

[0028] Step 4: Under an inert gas atmosphere, the organic lithium intermediate represented by formula (IV) and the tetrahydrofuran complex MX of the IV B group metal halide 1 m·yTHF reaction to generate the nitrogen-oxygen chelated transition metal complex catalyst shown in formula (I), where M represents a transition metal atom of Group IVB, and X 1 Selected from halogen atoms, m=3, 4 (the specific number is determined by the metal valence state), y=0, 1, 2 (the specific number is determined by the metal coordination number);

[0029]

[0030] Preferably, the inert gas atmosphere in the above steps is selected from high-purity nitrogen, high-purity argon, etc.

[0031] Preferably, in step 1, the halogenated hydrocarbon is selected from C1-C 18 chloro, bromo or iodo alkane or aromatic hydrocarbon, the halogenated silane is selected from chlorosilane, C1-C 18 Alkyl or aryl substituted chlorosilane, the phosphine halide is selected from phosphine chloride, C1-C 18 Alkyl or aryl substituted phosphine chloride.

[0032] Preferably, in step 1, the base is selected from sodium carbonate, potassium carbonate, potassium phosphate, potassium tert-butoxide, n-butyl lithium or triethylamine, and the molar ratio of 1,w-amino alcohol, halogenated hydrocarbon / halogenated silane / halogenated phosphine and base is 1:1:2 to 1:1:4.

[0033] Preferably, in step 2, the ratio of the amount of the intermediate represented by formula (II) to the amount of the chloride containing the cyclopentadienyl and the bridging heteroatom is 2:1 to 1:2;

[0034] Preferably, in step 2, the intermediate represented by formula (II) and the chloride containing a cyclopentadienyl ring and a bridging heteroatom are selected from the following structures:

[0035]

[0036] Among them, R 1 ,R 2 ,R 3 ,R 4 Selected from hydrogen, C1-C 18 Alkyl or aryl, wherein R 1 ,R 2 ,R 3 ,R 4 The groups may be the same or different from each other, and adjacent groups may form bonds or rings with each other; R is selected from hydrogen, C1-C 18 The number of alkyl or aryl groups is determined by the valence state of Y, and they can be the same or different from each other. Adjacent groups can also form bonds or rings with each other. Y is selected from atoms such as silicon, carbon, and phosphorus.

[0037] Preferably, in step 3, the organolithium reagent is selected from methyllithium, n-butyllithium, tert-butyllithium;

[0038] Preferably, in step 3, the molar ratio of the ligand represented by formula (III) to the organolithium reagent is 1:2 to 1:4;

[0039] Preferably, in step 3, the low temperature is -78°C to 0°C;

[0040] Preferably, in step 4, the molar ratio of the organic lithium represented by formula (IV) to the tetrahydrofuran complex of the Group IV B metal halide is 1.1:1 to 1:1.

[0041] The reaction route of the preparation method of the catalyst is shown as follows:

[0042]

[0043] Furthermore, the nitrogen-oxygen chelated transition metal complex of the present invention is selected from one of the following structures:

[0044]

[0045] Among them, the i Pr represents isopropyl, and Ph represents phenyl.

[0046] Furthermore, the nitrogen-oxygen chelated transition metal complex catalyst is preferably one of the structures shown below:

[0047]

[0048] The present invention also provides the use of the nitrogen-oxygen chelated transition metal complex as a catalyst in olefin polymerization.

[0049] Furthermore, the application uses the transition metal complex of the present invention as a main catalyst, and catalyzes olefin polymerization under the action of co-catalysts methylaluminoxane and borane.

[0050] Furthermore, the polymerized olefin monomer used is one or more of ethylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene and the like.

[0051] Furthermore, the olefin polymerization is a copolymerization reaction of ethylene and α-olefin.

[0052] Furthermore, the polymerization reaction is carried out in n-hexane solvent under the joint action of methylaluminoxane and borane, the ratio of the amount of methylaluminoxane to the central metal substance of the main catalyst is 100-1000:1, the ratio of the amount of borane to the central metal substance of the main catalyst is 2-8:1, the polymerization temperature is 115-135°C, and the polymerization pressure is 3-4MPa.

[0053] Compared with the prior art, the catalyst of the present invention introduces oxygen atoms and the groups connected thereto into the catalyst, so that the catalyst and the ligand are chelated. The coordination between the Ti active center cation and oxygen is stable, which prolongs the activity maintenance time of the catalyst. At the same time, the coordination between the oxygen atom and the central metal keeps the central metal away from the aggregation position of the large group, so that the olefin insertion space around the central metal becomes larger, making the catalyst easier to activate and the copolymerization insertion rate greater. DETAILED DESCRIPTION

[0054] In order to better understand the technical solution of the present invention, the content of the present invention is further described below in conjunction with the following specific examples, but the content of the present invention is not limited to the following examples, and the experimental methods used in the following examples are all conventional methods unless otherwise specified.

[0055] The following examples provide those of ordinary skill in the art with an understanding of how to make and evaluate the present invention, which are exemplary of the present disclosure and are not intended to limit the scope of the invention. Although every effort has been made to ensure accuracy with respect to numerical values ​​(e.g., amounts, temperatures, etc.), some errors and deviations should be considered. Unless otherwise stated, temperatures are in ° C or at ambient temperature, and pressures are at or near atmospheric pressure.

[0056] The preparation method for the disclosed compound described in the present embodiment is one of many methods, and there are many other methods for the preparation method of the disclosed compound in the present application, and the present application does not limit the scope. Therefore, those skilled in the art of the present disclosure can easily modify the described method or use different methods to prepare one or more of the disclosed compounds. The following method is only exemplary, and temperature, catalyst, concentration, reactant composition, and other process conditions can be changed, and for the desired compound, those skilled in the art of the present disclosure can easily select suitable reactants and conditions for preparation.

[0057] The present invention specifically adopts the following typical but non-limiting preparation process to implement the preparation method of the nitrogen-oxygen chelated transition metal complex in the summary of the invention:

[0058] Step 1 is: under the protection of inert gas, 1,w-amino alcohol and potassium carbonate are added to dichloromethane solvent in a Schlenk reaction bottle and mixed, and then C1-C 18 The halides of alkanes or aromatics, halides of silanes or silicon aromatics, or halides of phosphine or phosphorus aromatics are heated to 40°C and stirred for 2 hours. After the reaction is completed, water is added to separate the aqueous phase and the organic phase. The aqueous phase is extracted with dichloromethane for 3 times, the organic phase is dried by rotary evaporation, and the substance represented by formula (II) is obtained. 1,w-amino alcohol, potassium carbonate, C1-C 18The molar ratio of the alkane or aromatic halide, the silane or silaromatic halide, or the phosphane or phosphane halide is 1:2-5:1, preferably 1,w-amino alcohol, potassium carbonate, C1-C 18 The molar ratio of the alkane or arene halide, the silane or silaromatic halide, or the phosphane or phosphane halide is 1:2:1.

[0059] Step 2 is: under the protection of inert gas, dissolve the substance of formula (II) in n-hexane in a Schlenk reaction bottle, then slowly dropwise add the chloride containing cyclopentadienyl and bridging heteroatoms at 0°C, continue stirring for 12-24 hours after the dropwise addition is completed, filter and drain, wash the solid with n-hexane, and drain the obtained liquid to obtain the bridged ligand containing cyclopentadienyl, bridging heteroatoms and oxygen atoms shown in formula (III). The ratio of the amount of the substance of formula (II) to the amount of the chloride containing cyclopentadienyl and bridging heteroatoms is 1:1-3.

[0060] Step 3 is: under the protection of inert gas, a bridging ligand containing a cyclopentadienyl ring, a bridging heteroatom and an oxygen atom as shown in formula (III) is added to a Schlenk reaction bottle, and then a n-hexane solution of n-butyl lithium is slowly added dropwise at -78°C, the mixture is returned to room temperature, stirring is continued for 12-24 hours, vacuum dried, filtered, and the solid is vacuum dried to obtain a lithium salt of the ligand as shown in formula (IV).

[0061] Step 4 is: under the protection of inert gas, add the tetrahydrofuran complex of metal halide MX into the Schlenk reaction bottle. n To a tetrahydrofuran solution of yTHF (M represents a transition metal atom of Group IVB, X is selected from a halogen atom, n=0, 1, 2..., y=0, 1, 2...), a tetrahydrofuran solution of a lithium salt of a ligand represented by formula (IV) is slowly added dropwise at -78°C, and stirring is continued for 30 minutes. Then, lead dichloride is added, and stirring is continued for 2-4 hours. The product is filtered, dried in vacuo, washed with n-hexane, and recrystallized at -20°C to obtain a nitrogen-oxygen chelated transition metal complex represented by formula (I).

[0062] The preparation method of the nitrogen-oxygen chelated transition metal complex catalyst provided by the invention is carried out under the protection of an inert gas during the entire reaction process, and the inert gas is one of nitrogen and argon.

[0063] The technical solution of the present invention will be further described below through specific embodiments.

[0064] Example 1

[0065] Synthesis of ligand L1

[0066]

[0067] Under nitrogen protection, 2-amino-2-methyl-1-propanol (7.12 g, 80 mmol) and potassium carbonate (0.69 g, 5 mmol) were added to a dry 100 mL Schlenk reaction bottle, and the mixture was mixed in dichloromethane solvent (300 ml). Then trimethylsilyl chloride (8.72 g, 80 mmol) was slowly added dropwise, and the temperature was raised to 40°C. Stirring was continued for 2 hours. After the reaction was completed, water (200 ml) was added, and the aqueous phase and the organic phase were separated. The aqueous phase was extracted with dichloromethane for 3 times, and the organic phase was spin-dried and distilled under reduced pressure with a water pump to obtain 2-amino-2-methyl-1-trimethylsilyl methyl ether (8.35 g, 52 mmol) with a yield of 65%.

[0068] Under nitrogen protection, 2-amino-2-methyl-1-trimethylsilylmethyl ether (3.22 g, 20 mmol) was added to a dry 100 mL Schlenk reaction bottle, and n-hexane solvent (200 ml) was added. Tetramethylcyclopentadienylsilyl chloride (2.15 g, 10 mmol) was slowly added dropwise at 0°C, and the mixture was returned to room temperature and stirred for 12-24 hours. After the reaction was completed, the mixture was filtered and dried, and the solid was washed with n-hexane. The obtained liquid was dried to obtain ligand L1 (4.81 g, 14 mmol) with a yield of 70%.

[0069] H NMR spectrum: 1 H NMR (300MHz, CDCl3) δ3.95(s,2H),2.63(s,1H),2.11(s,6H),1.76(s,6H),1.20(s,6H),0.22(s,9H),0.08(s,6H).

[0070] Carbon NMR Spectrum: 13 C NMR (101MHz, CDCl3) δ135.5,127.5,82.7,56.7,41.3,27.5,20.6,11.1,3.7,2.2.

[0071] Example 2

[0072] Synthesis of ligand L2

[0073]

[0074] Under nitrogen protection, 2-amino-2-methyl-1-propanol (0.712 g, 8 mmol) and potassium carbonate (2.208 g, 16 mmol) were added to a dry 100 mL Schlenk reaction bottle, and the mixture was mixed in dichloromethane solvent (300 ml). Triphenylsilyl chloride (2.360 g, 8 mmol) was then slowly added dropwise, the temperature was raised to 40°C, and stirring was continued for 2 hours. After the reaction was completed, water (200 ml) was added, extracted, and the aqueous phase and the organic phase were separated. The aqueous phase was extracted 3 times with dichloromethane, and the organic phase was spin-dried. The solvent was removed by distillation under reduced pressure to obtain a crude product of 2-amino-2-methyl-1-triphenylsilyl methyl ether. The crude product was separated by column chromatography to obtain 2-amino-2-methyl-1-triphenylsilyl methyl ether (1.743 g, 5 mmol) with a yield of 62.5%.

[0075] Under nitrogen protection, 2-amino-2-methyl-1-triphenylsilylmethyl ether (0.696 g, 2 mmol) was added to a dry 100 mL Schlenk reaction bottle, and n-hexane solvent (30 ml) was added. Tetramethylcyclopentadienylsilyl chloride (0.215 g, 1 mmol) was slowly added dropwise at 0°C, and the mixture was returned to room temperature and stirred for 12-24 hours. After the reaction was completed, the mixture was filtered and dried, and the solid was washed with n-hexane. The resulting liquid was dried to obtain ligand L2 (0.842 g, 1.6 mmol) with a yield of 80%.

[0076] H NMR spectrum: 1 H NMR (300MHz, CDCl3) δ7.45-7.35(m,15H),3.91(s,2H),2.67(s,1H),2.14(s,6H),1.76(s,6H),1.21(s,6H),0.06(s,6H).

[0077] Example 3

[0078] Synthesis of ligand L3

[0079]

[0080] Under nitrogen protection, diphenylchlorophosphine (1.105 g, 5 mmol) was added to a dry 250 mL Schlenk reaction bottle, dichloromethane solvent (50 ml) was added, triethylamine (1 M, 5 mL) was added, and the mixture was stirred at room temperature for 30 min. 2-amino-2-methyl-1-propanol (0.445 g, 5 mmol) was added at 0°C, the temperature was restored to room temperature, and stirring was continued for 24 hours. After the reaction was completed, the mixture was filtered, and the filtrate was dried with a water pump. The crude product was separated by column chromatography to obtain 2-amino-2-methyl-1-diphenylphosphine methyl ether (1.1201 g, 4.1 mmol) with a yield of 82%.

[0081] Under nitrogen protection, 2-amino-2-methyl-1-diphenylphosphine methyl ether (0.273 g, 1 mmol) was added to a dry 100 mL Schlenk reaction bottle, and n-hexane solvent (30 ml) was added. Tetramethylcyclopentadienylsilyl chloride (0.215 g, 1 mmol) was slowly added dropwise at 0°C, and the mixture was returned to room temperature and stirred for 12-24 hours. After the reaction was completed, the mixture was filtered and dried, and the solid was washed with n-hexane. The obtained liquid was dried to obtain ligand L3 (0.317 g, 0.7 mmol) with a yield of 70%.

[0082] H NMR spectrum: 1 H NMR(300MHz, CDCl3)δ7.44(t,J=8.0Hz,6H),7.18(d,J=8.0Hz,4H),3.9(s,1H), 3.65(s,2H),2.62(s,1H),2.14(s,6H),1.77(s,6H),1.25(s,6H),0.07(s,6H).

[0083] Example 4

[0084] Synthesis of catalyst CAT1

[0085]

[0086] Under nitrogen protection, ligand L1 (3.06 g, 9 mmol) was added to a dry 500 mL Schlenk reaction bottle, and then n-butyl lithium n-hexane solution (2.4 M, 18 mmol) was slowly added dropwise at -78 °C, returned to room temperature, and stirred for 12-24 hours. The mixture was filtered, washed three times with n-hexane, and the solid was drained to obtain the lithium salt of ligand L1 (2.373 g, 6.7 mmol) with a yield of 74%.

[0087] Under nitrogen protection, titanium trichloride tetrahydrofuran complex TiCl3·3THF (1.480 g, 4 mmol) was added to a dry 100 mL Schlenk reaction bottle, and then 100 mL of tetrahydrofuran solvent was added. The tetrahydrofuran solution (0.5 M, 4 mmol) of the lithium salt of ligand L1 (1.416 g, 4 mmol) was slowly added dropwise at -78°C, and stirring was continued for 30 min. Lead dichloride (0.556 g, 2 mmol) was added and stirring was continued for 2 hours. The resulting mixture was filtered, the filtrate was vacuum dried, and washed with n-hexane until the filtrate was bright yellow. A large amount of n-hexane solvent was removed from the filtrate, and the concentrated bright yellow solution was frozen and recrystallized. The catalyst CAT1 (1.414 g, 3.1 mmol) was obtained by filtration with a yield of 76%.

[0088] H NMR spectrum: 1H NMR (300MHz, C6D6) δ3.95(s,2H),2.14(s,6H),1.75(s,6H),1.24(s,6H),0.23(s,9H),0.06(s,6H).

[0089] Example 5

[0090] Synthesis of catalyst CAT2

[0091]

[0092] Under nitrogen protection, ligand L2 (2.63 g, 5 mmol) was added to a dry 500 mL Schlenk reaction bottle, and then n-butyl lithium n-hexane solution (2.4 M, 10 mmol) was slowly added dropwise at -78 °C, returned to room temperature, and stirred for 12-24 hours. The mixture was filtered, washed three times with n-hexane, and the solid was drained to obtain the lithium salt of ligand L2 (2.061 g, 3.8 mmol) with a yield of 76%.

[0093] Under nitrogen protection, titanium trichloride tetrahydrofuran complex TiCl3·3THF (0.740 g, 2 mmol) was added to a dry 250 mL Schlenk reaction bottle, and then 50 mL of tetrahydrofuran solvent was added. A tetrahydrofuran solution (0.5 M, 2 mmol) of lithium salt of ligand L2 (1.08 g, 2 mmol) was slowly added dropwise at -78°C, and stirring was continued for 30 min. Lead dichloride (0.556 g, 2 mmol) was added and stirring was continued for two hours. The resulting mixture was filtered, the filtrate was vacuum dried, and washed with n-hexane until the filtrate was bright yellow. A large amount of n-hexane solvent was removed from the filtrate, and the concentrated bright yellow solution was frozen and recrystallized. The catalyst CAT2 (1.0293 g, 1.6 mmol) was obtained by filtration with a yield of 80%.

[0094] H NMR spectrum: 1 H NMR (300MHz, CDCl3) δ7.44-7.35(m,15H),3.91(s,2H),2.15(s,6H),1.76(s,6H),1.23(s,6H),0.07(s,6H).

[0095] Example 6

[0096] Synthesis of catalyst CAT3

[0097]

[0098] Under nitrogen protection, ligand L3 (2.260 g, 5 mmol) was added to a dry 250 mL Schlenk reaction bottle, and then n-butyl lithium n-hexane solution (2.4 M, 10 mmol) was slowly added dropwise at -78 °C, returned to room temperature, and stirred for 12-24 hours. The mixture was filtered, washed three times with n-hexane, and the solid was drained to obtain the lithium salt of ligand L3 (1.819 g, 3.9 mmol) with a yield of 78%.

[0099] Under nitrogen protection, ZrCl4·2THF (0.754 g, 2 mmol) of tetrahydrofuran complex of potassium tetrachloride was added to a dry 250 mL Schlenk reaction bottle, and 50 mL of tetrahydrofuran solvent was added. A tetrahydrofuran solution (0.5 M, 2 mmol) of lithium salt of ligand L3 (0.932 g, 2 mmol) was slowly added dropwise at -78°C, and stirring was continued for 2 hours. The resulting mixture was filtered, the filtrate was vacuum dried, and washed with n-hexane until the filtrate was bright yellow. A large amount of n-hexane solvent was removed from the filtrate, and the concentrated bright yellow solution was frozen and recrystallized, and the catalyst CAT3 (0.980 g, 1.6 mmol) was obtained by filtration with a yield of 80%.

[0100] H NMR spectrum: 1 H NMR (300MHz, CDCl3) δ7.46 (t, J = 8.0 Hz, 6H), 7.14 (d, J = 8.0 Hz, 4H), 3.7 (s, 1H), 3.66 (s, 2H), 2.15 (s, 6H), 1.81 (s, 6H), 1.21 (s, 6H), 0.09 (s, 6H).

[0101] The present invention provides an olefin polymerization method, which is carried out under the catalysis of the above-mentioned nitrogen-oxygen chelated transition metal complex catalyst. Preferably, the above-mentioned nitrogen-oxygen chelated transition metal complex catalyst is used as a main catalyst, and catalyzes the olefin polymerization reaction under the joint action of cocatalysts methylaluminoxane and borane.

[0102] The nitrogen-oxygen chelated transition metal complex catalyst of the present invention can be used to catalyze the polymerization of olefin monomers including at least one of ethylene, propylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-heptene, 1-octene, 1-decene, 1-undecene and 1-dodecene.

[0103] Example 7

[0104] Copolymerization of ethylene and 1-octene catalyzed by catalyst CAT1

[0105] The copolymerization of ethylene and 1-octene was carried out in a 100mL polymerization reactor equipped with a cooling reflux device and a magnetic stirrer. 35mL of n-hexane, 1.33mL of MAO (1.5M), a toluene solution of borane (8μmol / mL, 1mL), 9mL of 1-octene and a toluene solution of catalyst CAT1 (0.0009g, 2μmol, 1mL) were added to the dry 100mL polymerization reactor in sequence, and 35bar of ethylene monomer was introduced. The polymerization reaction began. During the entire polymerization process, the stirring rate and ethylene pressure remained unchanged, and the polymerization temperature was maintained at 115°C by a cooling device. After 10 minutes, the reaction solution was neutralized with a 5wt% hydrochloric acid-acidified industrial alcohol solution to obtain a polymer precipitate, which was washed several times and vacuum dried to constant weight. 1.41g of polymer was obtained, and the polymerization activity was 4.23×10 6 (g·mol -1 ·h -1 ), octene conversion rate is 25%, Mw (weight average molecular weight of polymer) = 2.01 × 10 5 g / mol, Mw / Mn (molecular weight distribution index of the polymer) = 1.67, octene insertion rate (measured and calculated by carbon nuclear magnetic resonance spectrum) = 15.0%.

[0106] Comparative Example 1

[0107] Copolymerization of ethylene and 1-octene catalyzed by CGC

[0108] The copolymerization of ethylene and 1-octene was carried out in a 100mL polymerization reactor equipped with a cooling reflux device and a magnetic stirrer. 35mL of n-hexane, 1.33mL of MAO (1.5M), a toluene solution of borane (8μmol / mL, 1mL), 9mL of 1-octene and a toluene solution of catalyst CGC (0.0007g, 2μmol, 1mL) were added to the dry 100mL polymerization reactor in sequence, and 35bar of ethylene monomer was introduced. The polymerization reaction began. During the entire polymerization process, the stirring rate and ethylene pressure remained unchanged, and the polymerization temperature was maintained at 115°C by a cooling device. After 10 minutes, the reaction solution was neutralized with a 5wt% hydrochloric acid-acidified industrial alcohol solution to obtain a polymer precipitate, which was washed several times and vacuum dried to constant weight. 1.30g of polymer was obtained, and the polymerization activity was 3.90×10 6 (g·mol -1 ·h -1 ), octene conversion rate is 21%, Mw (weight average molecular weight of polymer) = 1.74 × 10 5 g / mol, Mw / Mn (molecular weight distribution index of the polymer) = 1.56, octene insertion rate (measured and calculated by carbon nuclear magnetic resonance spectrum) = 14.5%.

[0109] Comparative Example 2

[0110] Copolymerization of ethylene and 1-octene catalyzed by CGC

[0111] The copolymerization of ethylene and 1-octene was carried out in a 100mL polymerization reactor equipped with a cooling reflux device and a magnetic stirrer. 35mL of n-hexane, 1.33mL of MAO (1.5M), a toluene solution of borane (8μmol / mL, 1mL), 9mL of 1-octene and a toluene solution of catalyst CGC (0.0007g, 2μmol, 1mL) were added to the dry 100mL polymerization reactor in sequence, and 35bar of ethylene monomer was introduced. The polymerization reaction began. During the entire polymerization process, the stirring rate and ethylene pressure remained unchanged, and the polymerization temperature was maintained at 115°C by a cooling device. After 30 minutes, the reaction solution was neutralized with a 5wt% hydrochloric acid-acidified industrial alcohol solution to obtain a polymer precipitate, which was washed several times and vacuum dried to constant weight. 2.20g of polymer was obtained, and the polymerization activity was 2.20×10 6 (g·mol -1 ·h -1 ), octene conversion rate is 20%, Mw (weight average molecular weight of polymer) = 1.88 × 10 5 g / mol, Mw / Mn (molecular weight distribution index of the polymer) = 1.72, octene insertion rate (measured and calculated by carbon nuclear magnetic resonance spectrum) = 14.3%.

[0112] Example 8

[0113] Copolymerization of Ethylene and 1-Octene Catalyzed by Catalyst CAT2

[0114] The copolymerization of ethylene and 1-octene was carried out in a 100 mL polymerization reactor equipped with a cooling reflux device and a magnetic stirrer. 35 mL of n-hexane, 1.33 mL of MAO (1.5 M), a toluene solution of borane (8 μmol / mL, 1 mL), 9 mL of 1-octene and a toluene solution of catalyst CAT2 (0.0013 g, 2 μmol, 1 mL) were added to the dry 100 mL polymerization reactor in sequence, and 35 bar of ethylene monomer was introduced. The polymerization reaction began. During the entire polymerization process, the stirring rate and ethylene pressure remained unchanged, and the polymerization temperature was maintained at 115 ° C by a cooling device. After 30 minutes, the reaction solution was neutralized with a 5 wt% hydrochloric acid-acidified industrial alcohol solution to obtain a polymer precipitate, which was washed several times and vacuum dried to constant weight. 4.79 g of polymer was obtained, and the polymerization activity was 4.79×10 6 (g·mol -1 ·h -1 ), octene conversion rate is 31%, Mw (weight average molecular weight of polymer) = 1.89 × 10 5g / mol, Mw / Mn (molecular weight distribution index of the polymer) = 1.55, octene insertion rate (measured and calculated by carbon nuclear magnetic resonance spectrum) = 17%.

[0115] Example 9

[0116] Copolymerization of Ethylene and 1-Octene Catalyzed by Catalyst CAT3

[0117] The copolymerization of ethylene and 1-octene was carried out in a 100mL polymerization reactor equipped with a cooling reflux device and a magnetic stirrer. 35mL of n-hexane, 1.33mL of MAO (1.5M), a toluene solution of borane (8μmol / mL, 1mL), 9mL of 1-octene and a toluene solution of catalyst CAT2 (0.0011g, 2μmol, 1mL) were added to the dry 100mL polymerization reactor in sequence, and 35bar of ethylene monomer was introduced. The polymerization reaction began. During the entire polymerization process, the stirring rate and ethylene pressure remained unchanged, and the polymerization temperature was maintained at 115°C by a cooling device. After 30 minutes, the reaction solution was neutralized with a 5wt% hydrochloric acid-acidified industrial alcohol solution to obtain a polymer precipitate, which was washed several times and vacuum dried to constant weight. 4.61g of polymer was obtained, and the polymerization activity was 4.61×10 6 (g·mol -1 ·h -1 ), octene conversion rate is 30%, Mw (weight average molecular weight of polymer) = 1.44 × 10 5 g / mol, Mw / Mn (molecular weight distribution index of the polymer) = 1.79, octene insertion rate (measured and calculated by carbon nuclear magnetic resonance spectrum) = 16.2%.

[0118] Example 10

[0119] Copolymerization of Ethylene and 1-Heptene Catalyzed by Catalyst CAT3

[0120] The copolymerization of ethylene and 1-heptene was carried out in a 100 mL polymerization reactor equipped with a cooling reflux device and a magnetic stirrer. 35 mL of n-hexane, 1.33 mL of MAO (1.5 M), a toluene solution of borane (8 μmol / mL, 1 mL), 3 mL of 1-heptene and a toluene solution of catalyst CAT3 (0.0011 g, 2 μmol, 1 mL) were added to the dry 100 mL polymerization reactor in sequence, and 35 bar of ethylene monomer was introduced. The polymerization reaction began. During the entire polymerization process, the stirring rate and ethylene pressure remained unchanged, and the polymerization temperature was maintained at 115 ° C by a cooling device. After 30 minutes, the reaction solution was neutralized with a 5 wt% hydrochloric acid-acidified industrial alcohol solution to obtain a polymer precipitate, which was washed several times and vacuum dried to constant weight. 4.74 g of polymer was obtained, and the polymerization activity was 4.74×10 6 (g·mol-1 ·h -1 ), heptene conversion rate was 32%, Mw (weight average molecular weight of polymer) = 1.21 × 10 5 g / mol, Mw / Mn (molecular weight distribution index of the polymer) = 1.81, heptene insertion rate (measured and calculated by carbon nuclear magnetic resonance spectrum) = 16.8%.

[0121] Embodiment 11

[0122] Copolymerization of Ethylene and 1-Nonene Catalyzed by Catalyst CAT3

[0123] The copolymerization of ethylene and 1-nonene was carried out in a 100 mL polymerization reactor equipped with a cooling reflux device and a magnetic stirrer. 35 mL of n-hexane, 1.33 mL of MAO (1.5 M), a toluene solution of borane (8 μmol / mL, 1 mL), 4 mL of 1-nonene and a toluene solution of catalyst CAT3 (0.0011 g, 2 μmol, 1 mL) were added to the dry 100 mL polymerization reactor in sequence, and 35 bar of ethylene monomer was introduced. The polymerization reaction began. During the entire polymerization process, the stirring rate and ethylene pressure remained unchanged, and the polymerization temperature was maintained at 115 ° C by a cooling device. After 30 minutes, the reaction solution was neutralized with a 5 wt% hydrochloric acid-acidified industrial alcohol solution to obtain a polymer precipitate, which was washed several times and vacuum dried to constant weight. 4.82 g of polymer was obtained, and the polymerization activity was 4.82×10 6 (g·mol -1 ·h -1 ), nonene conversion rate is 31%, Mw (weight average molecular weight of polymer) = 1.46 × 10 5 g / mol, Mw / Mn (molecular weight distribution index of the polymer) = 1.65, nonene insertion rate (measured and calculated by carbon nuclear magnetic resonance spectrum) = 17.5%.

[0124] Example 12

[0125] Copolymerization of ethylene and 1-decene catalyzed by catalyst CAT3

[0126] The copolymerization of ethylene and 1-decene was carried out in a 100mL polymerization reactor equipped with a cooling reflux device and a magnetic stirrer. 35mL of n-hexane, 1.33mL of MAO (1.5M), a toluene solution of borane (8μmol / mL, 1mL), 3mL of 1-decene and a dichloromethane solution of catalyst CAT3 (0.0011g, 2μmol, 1mL) were added to the dry 100mL polymerization reactor in sequence, and 35bar of ethylene monomer was introduced. The polymerization reaction began. During the entire polymerization process, the stirring rate and ethylene pressure remained unchanged, and the polymerization temperature was maintained at 115°C by a cooling device. After 30 minutes, the reaction solution was neutralized with a 5wt% hydrochloric acid-acidified industrial alcohol solution to obtain a polymer precipitate, which was washed several times and vacuum dried to constant weight. 4.99g of polymer was obtained, and the polymerization activity was 4.99×10 6 (g·mol -1 ·h -1 ), decene conversion rate is 32%, Mw (weight average molecular weight of polymer) = 1.90 × 10 5 g / mol, Mw / Mn (molecular weight distribution index of the polymer) = 1.79, decene insertion rate (measured and calculated by carbon nuclear magnetic resonance spectrum) = 18%.

[0127] It can be seen from the above embodiments that the present invention provides a nitrogen-oxygen chelated transition metal complex, which can initiate coordination polymerization under the joint action of methylaluminoxane and borane. The complex is used as a catalyst to catalyze the copolymerization of ethylene with 1-octene and long-chain α-olefins, and a polymer product with high molecular weight, high comonomer insertion rate and narrow molecular weight distribution can be obtained with high activity.

[0128] The experimental results show that the molecular weight of the polymer obtained by copolymerizing ethylene and 1-octene catalyzed by the nitrogen-oxygen chelated transition metal complex catalyst provided by the present invention can reach up to 2.01×10 5 g / mol, the highest 1-octene molar insertion rate is 17%, the smallest molecular weight distribution is 1.55, the activity maintenance time can reach 30min, and the polymerization activity can reach 4.79×10 6 (g·mol -1 ·h -1 ); The molecular weight of the polymer obtained by copolymerization of ethylene and 1-heptene can reach up to 1.21×10 5 g / mol, the highest 1-heptene molar insertion rate was 16.8%, the smallest molecular weight distribution was 1.81, the activity maintenance time could reach 30min, and the polymerization activity could reach 4.74×10 6 (g·mol -1 ·h -1 ); The molecular weight of the polymer obtained by copolymerization of ethylene and 1-nonene can reach up to 1.46×10 5g / mol, the highest molar insertion rate of 1-nonene is 17.5%, the smallest molecular weight distribution is 1.65, the activity maintenance time can reach 30min, and the polymerization activity can reach 4.82×10 6 (g·mol -1 ·h -1 ); The molecular weight of the polymer obtained by copolymerization of ethylene and 1-decene can reach up to 1.90×10 5 g / mol, the highest 1-decene molar insertion rate was 18%, the smallest molecular weight distribution was 1.79, the activity maintenance time could reach 30 min, and the polymerization activity could reach 4.99×10 6 (g·mol -1 ·h -1 ).

[0129] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A nitrogen-oxygen chelated transition metal complex catalyst, characterized in that: It has the structure shown in formula (I): in: R 1 , R 2 , R 3 , R 4 Selected from hydrogen, C1-C 18 Alkyl or aryl, wherein R 1 , R 2 , R 3 , R 4 The groups can be the same or different from each other, and adjacent groups can form bonds or rings with each other; R 5 Selected from hydrogen, C1-C 18 Alkyl or aryl, C1-C 18 Alkyl or aryl substituted silicon, C1-C 18 an alkyl or aryl substituted phosphino group; R 6 , R 7 Selected from hydrogen, C1-C 18 Alkyl groups or aryl groups may be the same or different from each other, and may form a bond or a ring with each other; R is selected from hydrogen, C1-C 18 Alkyl or aryl groups, the number of which is determined by the valence of Y, can be the same or different, and adjacent groups can form bonds or rings with each other; M is selected from a transition metal atom of Group IVB; X 1 , X 2 is a C1-C5 hydrocarbon group selected from halogen atoms, hydrogen atoms, C1-C5 hydrocarbon groups and alkoxy groups, carboxylate groups, aliphatic amine groups, aromatic amine groups, aliphatic phosphino groups, aromatic phosphino groups, alkylthio groups, borane, borate esters, alkylaluminum, and silane-substituted C1-C5 hydrocarbon groups; Y is selected from silicon, carbon or phosphorus atoms; n＝0，1，2，3，4，5。 2. The nitrogen-oxygen chelated transition metal complex catalyst according to claim 1, characterized in that: The transition metal complex catalyst is selected from one of the following structures: Among them, the i Pr represents isopropyl, and Ph represents phenyl.

3. A method for preparing the nitrogen-oxygen chelated transition metal complex catalyst according to claim 1, characterized in that: The steps include: Step 1: 1, w-amino alcohol Reaction with a halogenated hydrocarbon, a halogenated silane or a halogenated phosphine in the presence of a base to obtain an intermediate represented by formula (II); Step 2: Under an inert gas atmosphere, the intermediate represented by formula (II) is reacted with a chloride containing a cyclopentadienyl ring and a bridging heteroatom. Reaction to generate the ligand shown in formula (III); Step 3: Under an inert gas atmosphere, the ligand represented by formula (III) is mixed with an organic lithium reagent at low temperature, and then the temperature is raised to room temperature to react to prepare an organic lithium intermediate represented by formula (IV); Step 4: Under an inert gas atmosphere, the organic lithium intermediate represented by formula (IV) and the tetrahydrofuran complex MX of the IV B group metal halide 1 m ·yTHF reaction to generate the nitrogen-oxygen chelated transition metal complex catalyst shown in formula (I), where M represents a transition metal atom of Group IVB, and X 1 Selected from halogen atoms, m = 3, 4, y = 0, 1, 2; 4. The method for preparing the nitrogen-oxygen chelate transition metal complex catalyst according to claim 3, characterized in that: In step 1, the halogenated hydrocarbon is selected from C1-C 18 chloro, bromo or iodo alkane or aromatic hydrocarbon, the halogenated silane is selected from chlorosilane, C1-C 18 Alkyl or aryl substituted chlorosilane, the phosphine halide is selected from phosphine chloride, C1-C 18 Alkyl or aryl substituted phosphine chloride; in said step 1, the base is selected from sodium carbonate, potassium carbonate, potassium phosphate, potassium tert-butoxide, n-butyl lithium or triethylamine, and the molar ratio of 1,w-amino alcohol, halogenated hydrocarbon / halogenated silane / halogenated phosphine and base is 1:1:2 to 1:1:

4.

5. The method for preparing the nitrogen-oxygen chelate transition metal complex catalyst according to claim 3, characterized in that: In the step 2, the ratio of the intermediate of formula (II) to the chloride containing cyclopentadienyl and bridging heteroatoms is 2:1 to 1:

2.

6. The method for preparing the nitrogen-oxygen chelate transition metal complex catalyst according to claim 3, characterized in that: In step 3, the organic lithium reagent is selected from one or more of methyl lithium, n-butyl lithium or tert-butyl lithium; the molar ratio of the ligand represented by formula (III) to the organic lithium reagent is 1:2 to 1:4; and the temperature of the low temperature is -78°C to 0°C.

7. The method for preparing the nitrogen-oxygen chelate transition metal complex catalyst according to claim 3, characterized in that: In the step 4, the molar ratio of the organic lithium intermediate represented by formula (IV) to the tetrahydrofuran complex of the IV B group metal halide is 1.1:1 to 1:

1.

8. Use of the nitrogen-oxygen chelated transition metal complex catalyst according to claim 1 or 2 as a catalyst in olefin polymerization.

9. The use according to claim 8, characterized in that: The olefin is at least one selected from the group consisting of ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-decene, 1-undecene, and 1-dodecene.

10. The use according to claim 8, characterized in that: The olefin polymerization is a copolymerization reaction of ethylene and α-olefin.

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