A restricted configuration metallocene compound and its preparation method and application

Abstract

The present invention proposes a restricted configuration metallocene compound and a preparation method and application thereof, belonging to the technical field of polyolefin catalysts. The restricted configuration metallocene compound has a structure as shown in the following formula: #imgabs0# or #imgabs1# wherein R1, R2 are independently selected from hydrogen, methyl, ethyl, C3-C6 alkyl or aromatic group; R3 is independently selected from methyl, ethyl, C3-C6 alkyl, aromatic group or adamantyl group; R4-R7 are independently selected from hydrogen or methyl group; M is independently selected from titanium or zirconium. The CGC catalyst of the above-mentioned novel structure is mainly used for olefin polymerization and copolymerization. By adjusting the substituent, a functional group with weak coordination and steric effect is introduced on the bridge, which is convenient for controlling the spatial effect and electronic effect of the metal center, improving the stability of the catalyst and the insertion rate of α-olefins, and then better regulating the distribution of polymer molecular weight and copolymerization performance, improving the metallocene copolymerization ability and polymerization reaction temperature, and having important significance for producing high molecular weight copolymerized olefins.

Description

Technical Field

[0001] The present invention relates to the technical field of polyolefin catalysts, and in particular to a constrained configuration metallocene compound and a preparation method and application thereof. Background Art

[0002] As a core technology in the polyolefin industry, polyolefin catalysts have consistently garnered widespread attention from both domestic and international academic and industrial communities. The production of branched polyethylene through the copolymerization of ethylene with α-olefins (such as 1-hexene and 1-octene) using a copolymerization catalyst significantly enhances and expands polyethylene's applications. Therefore, developing highly active, high-temperature-resistant copolymerization catalysts with high insertion rates is crucial for the development of the polyolefin elastomer (POE) industry.

[0003] At present, the commonly used copolymerization catalyst is the metallocene catalyst. The ligand in the metallocene ligand structure plays a key role in its structure. Its steric hindrance and electronic effect can be adjusted within a wide range, thereby obtaining a catalyst with unique spatial and electronic properties.

[0004] Metallocene catalysts containing constrained geometry complexes (CGC) are the current mainstream metallocene catalysts. They are mainly based on a ring of cyclopentadiene (cyclopentadiene and various substituted cyclopentadienes), with one or more atoms in the middle acting as bridges (usually carbon or silicon, and different substituents can also be connected to the bridge atoms). The other end of the bridge is usually a nitrogen atom or a phosphorus atom (with a pair of lone electron pairs) and the corresponding substituent. The electrons in the nitrogen atom and the electrons on the ring of cyclopentadiene form a coordination potential with the metal center.

[0005] There are many CGC structures reported. For example, the classic tetramethylsilocene bridge CGC catalyst of Dow [Li L, Marks T. New Organo-Lewis Acids. Tris (β-perfluoronaphthyl) borane (PNB) as a Highly Active Cocatalyst for Metallocene-Mediated Ziegler-Natta α-Olefin Polymerization [J]. Organometallics, 1998, 17 (18), 3996-4003] has been applied in many fields. However, due to the limitation of the synthesis route, the diversity of substituents on the silicon bridge is far less than that on the carbon bridge. Kehr et al. [Kunz K, Erker G, Do¨ring S, et al. Generation of homogeneous (sp 3-C(1))-bridged Cp / amido and Cp / phosphidogroup 4metal Ziegler-Natta catalyst systems[J].Journal of the AmericanChemical Society,2001,123(25):6181-6182] The idea of ​​using tetramethylcyclopentadiene as a ligand was proposed when carbon-bridged CGC catalysts were first reported in 2001, but traditional synthetic methods make it difficult to prepare carbon-bridged CGC catalysts with large steric hindrance cyclopentadiene.

[0006] Therefore, it is urgent to adjust the substituents of CGC catalysts, propose carbon-bridge CGC catalysts with large steric hindrance cyclopentadiene and their specific synthesis methods, and enhance polymerization properties such as polymerization activity and high temperature resistance. Summary of the Invention

[0007] The present invention provides a restricted configuration metallocene compound and a preparation method and application thereof to solve the above technical problems.

[0008] One of the purposes of the present invention is to provide a constrained configuration metallocene compound having a structure shown in the following formula:

[0009]

[0010] in,

[0011] R1, R2 are independently selected from hydrogen, methyl, ethyl, C3-C6 alkyl or aromatic groups;

[0012] R3 is independently selected from methyl, ethyl, C3-C6 alkyl, aryl or adamantyl;

[0013] R4-R7 are independently selected from hydrogen or methyl;

[0014] M is independently selected from titanium or zirconium.

[0015] Furthermore, R4-R7 are independently selected from methyl.

[0016] Furthermore, the chemical formula of the compound is as follows:

[0017] [(η 5 -Me4C5)C(Me)2N(t-Bu)]TiCl2,

[0018] [(η 5 -C5H4)CH(Ph)N(t-Bu)]TiCl2,

[0019] [(η 5 -Me4C5)CH(Ph)N(t-Bu)]TiCl2,

[0020] [(η 5 -1-Ind)CH(Ph)N-Ada)]TiCl2,

[0021] [(η 5 -Me4C5)CH(Ph)N-Ada)]ZrCl2,

[0022] [(η 5 -Ind-1)CH(Ph)N-Ada)]ZrCl2,

[0023] or [(η 5 -Me4C5)C(Ph)2N-Ada)]ZrCl2.

[0024] Another object of the present invention is to provide a method for preparing the above-mentioned restricted configuration metallocene compound, comprising the following steps:

[0025] (1) Under the protection of inert gas or nitrogen, an amine compound, an aldehyde ketone compound, and a first solvent are added to a reactor with an organic acid as a catalyst, heated to reflux and then subjected to a first reaction. After cooling, the pH is adjusted to neutral, and after rotary evaporation, a polar solvent is added, and the mixture is filtered to obtain an imine compound;

[0026] (2) Under the protection of inert gas or nitrogen, at a temperature of -78 to 0°C, add an ether solution to the above-mentioned imine compound, then mix with any one of cyclopentadienyl lithium, tetramethylcyclopentadienyl lithium or indenyl lithium, and heat to room temperature to carry out a second reaction to obtain ligand a;

[0027] (3) Under the protection of inert gas or nitrogen, at a temperature of -78 to 0°C, the ligand a is mixed with an alkyl lithium, heated to reflux, and then subjected to a third reaction to obtain a ligand b;

[0028] (4) Under the protection of inert gas or nitrogen, at a temperature of -78 to 0°C, the above ligand b is mixed with MCl4·organic complexing agent, heated to room temperature, and then subjected to the fourth reaction, followed by recrystallization and separation to obtain the product.

[0029] Furthermore, in step (1), the aldehyde and ketone compound is an aldehyde compound or a ketone compound; preferably, the aldehyde and ketone compound is benzaldehyde, acetone, butanone, acetaldehyde or benzophenone;

[0030] In step (1), the amine compound is methylamine, tert-butylamine, allylamine, aniline, adamantaneamine or diaminobutane;

[0031] In step (1), the organic acid catalyst is at least one of p-toluenesulfonic acid, benzenesulfonic acid, trifluorosulfonic acid, and methanesulfonic acid;

[0032] In step (1), the molar ratio of the amine compound to the aldehyde and ketone compound is 4-5.

[0033] Furthermore, in step (2), the molar ratio of the imine compound to the cyclopentadienyl lithium, tetramethylcyclopentadienyl lithium or indenyl lithium is 1:1;

[0034] In step (2), the ether solution includes at least one of diethyl ether solution, anisole solution, and tetrahydrofuran solution.

[0035] Furthermore, in step (3), the alkyl lithium is methyl lithium, ethyl lithium, butyl lithium or tert-butyl lithium; preferably, the alkyl lithium is butyl lithium;

[0036] In step (3), the molar ratio of ligand a to alkyl lithium is 1:1 to 3; preferably, the molar ratio of ligand a to alkyl lithium is 1:1.

[0037] Furthermore, in step (4), in the MCl4·organic complexing agent: MCl4 is selected from one of TiCl4 and ZrCl4; the organic complexing agent is tetrahydrofuran, ether or N,N,N,N-tetramethylethylenediamine; preferably, the organic complexing agent is tetrahydrofuran;

[0038] In step (4), the molar ratio of ligand b to MCl4 is (0.9-1.5):1.

[0039] Another object of the present invention is to provide the use of the above-mentioned constrained configuration metallocene compound in olefin polymerization and copolymerization reactions.

[0040] Furthermore, the restricted configuration metallocene compound is used as a main catalyst, methylaluminoxane is used as a co-catalyst, and the molar ratio of the main catalyst to the co-catalyst is 1:500 to 6000.

[0041] The present invention has the following advantages:

[0042] The restricted configuration metallocene compound proposed by the present invention has a saturated carbon bridge structure, and a ligand with a functionalized effect is introduced into the cyclopentadienyl ligand, which can improve the stability and temperature tolerance of the metallocene active species under polymerization conditions. In addition, the introduction of a bulky aromatic group can also increase the catalyst operating temperature, strengthen the stability of the catalyst active species, and is suitable for producing ethylene / α-olefin copolymers under high temperature conditions. The CGC catalyst of the above-mentioned novel structure, by adjusting the substituents, introduces functional groups with weak coordination and steric effects on the bridge, facilitates the control of the steric effect and electronic effect of the metal center, improves the stability of the catalyst and the insertion rate of α-olefins, and thus better regulates the distribution of polymer molecular weight and copolymerization performance, improves the metallocene copolymerization ability and polymerization reaction temperature, and is of great significance for the production of high molecular weight co-olefins.

[0043] The present invention proposes a method for preparing a constrained-configuration metallocene compound. This method involves reacting a lithium salt of a large π-ligand metallocene ligand (or indene ligand) with an imine to introduce a carbon bridge and nitrogen atom in a single step. After lithiation, the metal complex is directly formed to produce the constrained-configuration compound. This method offers the advantages of a short synthetic route, a simple synthesis process, ease of separation and purification, high product yield, and low industrial cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] The accompanying drawings, which constitute part of the present invention, are provided to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are provided to explain the present invention and do not constitute an undue limitation of the present invention. In the accompanying drawings:

[0045] Figure 1 Complex C1 of the present invention 1 H NMR spectrum;

[0046] Figure 2 Complex C1 of the present invention 13 C NMR spectrum;

[0047] Figure 3 This is the hydrogen spectrum of catalyst C3 of the embodiment of the present invention;

[0048] Figure 4 This is the carbon spectrum of catalyst C3 of the embodiment of the present invention;

[0049] Figure 5 This is the hydrogen spectrum of the catalyst C4 of the embodiment of the present invention;

[0050] Figure 6 This is the C4 carbon spectrum of the catalyst of the embodiment of the present invention;

[0051] Figure 7 This is the hydrogen spectrum of catalyst C5 according to an embodiment of the present invention;

[0052] Figure 8 This is the carbon spectrum of catalyst C5 of the embodiment of the present invention;

[0053] Figure 9 This is the hydrogen spectrum of catalyst C6 of the embodiment of the present invention;

[0054] Figure 10 This is the carbon spectrum of catalyst C6 of the embodiment of the present invention;

[0055] Figure 11 The polymer obtained by polymerization of catalyst C5 in Test Example 2 of the present invention under the conditions shown in No. 5 in Table 3 13 C NMR spectrum;

[0056] Figure 12 This is the DSC graph of the polymer obtained by polymerization of catalyst C5 in Test Example 2 of the present invention under the conditions shown in No. 5 in Table 3;

[0057] Figure 13 The polymer obtained by polymerization of catalyst C5 in Test Example 2 of the present invention under the conditions shown in No. 6 in Table 3 13 C NMR spectrum;

[0058] Figure 14 This is the DSC graph of the polymer obtained by polymerizing the catalyst C5 of Test Example 2 of the present invention under the conditions shown in No. 6 in Table 3. DETAILED DESCRIPTION

[0059] The technical solution of the present invention is described in detail below with reference to the accompanying drawings, but the protection scope of the present invention is not limited to the embodiments.

[0060] One embodiment of the present invention provides a constrained configuration metallocene compound having the structure shown in the following formula:

[0061]

[0062] in,

[0063] R1, R2 are independently selected from hydrogen, methyl, ethyl, C3-C6 alkyl or aromatic groups;

[0064] R3 is independently selected from methyl, ethyl, C3-C6 alkyl, aryl or adamantyl;

[0065] R4-R7 are independently selected from hydrogen or methyl;

[0066] M is independently selected from titanium (Ti) or zirconium (Zr).

[0067] The restricted configuration metallocene compound proposed in the embodiment of the present invention has a saturated carbon atom as the bridge structure and is relatively rigid; compared with the silicon-bridged CGC, the bite angle is smaller, which is conducive to the insertion of large sterically hindered α-olefins. The ligand is a cyclopentadienyl ring anion, a tetramethylcyclopentadienyl anion or an indenyl anion, and the spatial configuration is stable. The introduction of phenyl groups on the bridge group of some structures can further improve the stability, so that the final catalyst has good catalytic activity and copolymerization ability. This restricted configuration metallocene compound can not only retain the activity of the single-site catalyst, but also facilitates the control of steric and electronic effects by adjusting the substituents, thereby regulating the molecular weight and distribution of the polymer, as well as copolymers with different insertion rates, thereby improving the stability, temperature tolerance and polymerization performance of the metallocene active species under polymerization conditions. It is the key to promoting the industrialization of metallocenes and is of great significance for the production of high molecular weight co-olefins.

[0068] In a preferred embodiment of the present invention, the chemical formula of the compound is as follows:

[0069] [(η 5-Me4C5)C(Me)2N(t-Bu)]TiCl2,

[0070] [(η 5 -C5H4)CH(Ph)N(t-Bu)]TiCl2,

[0071] [(η 5 -Me4C5)CH(Ph)N(t-Bu)]TiCl2,

[0072] [(η 5 -1-Ind)CH(Ph)N-Ada)]TiCl2,

[0073] [(η 5 -Me4C5)CH(Ph)N-Ada)]ZrCl2,

[0074] [(η 5 -Ind-1)CH(Ph)N-Ada)]ZrCl2,

[0075] or [(η 5 -Me4C5)C(Ph)2N-Ada)]ZrCl2.

[0076] It should be noted that Bu is the abbreviation of butyl, Me is the abbreviation of methyl, Ind is the abbreviation of indene, Ada is the abbreviation of adamantyl, Ti is the abbreviation of titanium, and Zr is the abbreviation of zirconium.

[0077] One embodiment of the present invention provides a method for preparing any of the above-mentioned restricted configuration metallocene compounds, comprising the following steps:

[0078] (1) Under the protection of inert gas or nitrogen, an amine compound, an aldehyde ketone compound, and a first solvent are added to a reactor with an organic acid as a catalyst, heated to reflux for a first reaction, cooled, adjusted to a neutral pH, and then rotary evaporated, and then a polar solvent is added, filtered, and an imine compound is obtained;

[0079] (2) Under the protection of inert gas or nitrogen, at a temperature of -78 to 0°C, add an ether solution to the above-mentioned imine compound, then mix with any one of cyclopentadienyl lithium, tetramethylcyclopentadienyl lithium or indenyl lithium, and heat to room temperature to carry out a second reaction to obtain ligand a;

[0080] (3) Under the protection of inert gas or nitrogen, at a temperature of -78 to 0°C, the ligand a is mixed with an alkyl lithium, heated to reflux, and then subjected to a third reaction to obtain a ligand b;

[0081] (4) Under the protection of inert gas or nitrogen, at a temperature of -78 to 0°C, the above ligand b is mixed with MCl4·organic complexing agent, heated to room temperature, and then subjected to the fourth reaction, followed by recrystallization and separation to obtain the product.

[0082] The method for preparing a constrained-configuration metallocene compound proposed in an embodiment of the present invention utilizes a lithium salt of a large π-ligand metallocene ligand (or indene ligand) to react with an imine, introducing a carbon bridge and nitrogen atom in a single step. After lithiation, the metal complex is directly formed to obtain the constrained-configuration compound. This method has the advantages of a short synthetic route, a simple synthesis process, easy separation and purification, high product yield, and low industrial cost.

[0083] In step (1) of the embodiment of the present invention, an organic acid is used as a catalyst to react an amine compound and an aldehyde or ketone compound to obtain an imine compound.

[0084] In step (1), the aldehyde and ketone compound is an aldehyde compound or a ketone compound; preferably, the aldehyde compound or the ketone compound is benzaldehyde, acetone, butanone, acetaldehyde or benzophenone.

[0085] In step (1), the amine compound is methylamine, tert-butylamine, allylamine, aniline, adamantaneamine or butanediamine.

[0086] In step (1), the organic acid catalyst is at least one of p-toluenesulfonic acid, benzenesulfonic acid, trifluorosulfonic acid, and methanesulfonic acid.

[0087] In step (1), the organic acid is used as a catalyst, and the amount of the organic acid used is generally 5% of the substrate weight.

[0088] The molar ratio of the amine compound to the aldehyde and ketone compound is 4-5.

[0089] In step (1), the first solvent is at least one of methanol, ethanol, and toluene. The polar solvent is dichloromethane (DCM).

[0090] In step (1), the rotary evaporation is mainly for removing the solvent and low-boiling components. The first reaction time is 1 to 20 hours.

[0091] In step (1), step (2), step (3) and step (4), the inert gas includes argon gas or the like.

[0092] In step (2) of the embodiment of the present invention, cyclopentadienyl ring anion, tetramethylcyclopentadienyl anion and indenyl anion are selected as large π ligands, and the imine compound is reacted with cyclopentadienyl lithium, tetramethylcyclopentadienyl lithium or indenyl lithium to introduce a carbon bridge and a nitrogen atom in one step to obtain a ligand containing a carbon bridge and a nitrogen atom.

[0093] In step (2), the molar ratio of the imine compound to the cyclopentadienyl lithium, tetramethylcyclopentadienyl lithium or indenyl lithium is 1:1.

[0094] In step (2), cyclopentadienyllithium, tetramethylcyclopentadienyllithium or indenyllithium is mainly added in the form of an ether solution of cyclopentadienyllithium, tetramethylcyclopentadienyllithium or indenyllithium.

[0095] In step (2), the ether solution includes at least one of diethyl ether solution, anisole solution, and tetrahydrofuran solution.

[0096] In step (2), the second reaction time is 5-20 hours. Preferably, the second reaction time is 12 hours.

[0097] In step (2), the room temperature is 20-50° C. Preferably, the room temperature is 20-30° C. More preferably, the room temperature is 25° C.

[0098] In step (3) of the embodiment of the present invention, the ligand a obtained in step (2) is lithiated with an alkyl lithium to facilitate complexation with subsequent metals.

[0099] In step (3), the alkyl lithium is methyl lithium, ethyl lithium, butyl lithium or tert-butyl lithium. Preferably, the alkyl lithium is butyl lithium.

[0100] In step (3), the molar ratio of ligand a to alkyl lithium is 1:1 to 3. Preferably, the molar ratio of ligand a to alkyl lithium is 1:1.

[0101] In step (3), the third reaction time is 5-20 hours.

[0102] In step (4) of the embodiment of the present invention, the ligand after the lithiation in step (3) is directly complexed with a metal halide to obtain a restricted configuration compound.

[0103] In step (4), the MCl4 in the MCl4·2THF is selected from one of TiCl4 and ZrCl4.

[0104] In step (4), the organic complexing agent is tetrahydrofuran (THF), ether or N,N,N,N-tetramethylethylenediamine. Preferably, the organic complexing agent is THF.

[0105] In step (4), the molar ratio of ligand b to MCl4 is (0.9-1.5):1.

[0106] In step (4), the fourth reaction time is 5 to 20 hours.

[0107] One embodiment of the present invention further provides the use of any of the above-mentioned constrained configuration metallocene compounds in olefin polymerization and copolymerization reactions.

[0108] The catalyst system of the metallocene compound / MAO with limited configuration in the embodiment of the present invention still has high activity for ethylene polymerization and copolymerization under the condition of low co-catalyst ratio, and the highest ethylene polymerization activity reaches 6.64×10 6 g / molCat / h, the polymer molecular weight reaches 1.00×10 5 ~4.23×10 5 g / mol, and the polymer can be used as POE. The ethylene-1-octene copolymer is prepared, and the 1-octene content in the polymer is 4.49w% to 49.94w%, and the crystallinity of the polymer is between 5% and 50%.

[0109] In one embodiment of the present invention, the restricted configuration metallocene compound is used as the main catalyst, methylaluminoxane is used as the co-catalyst, and the molar ratio of the main catalyst to the co-catalyst is 1:500-6000.

[0110] The restricted configuration metallocene compound is used as a main catalyst, methylaluminoxane is used as a co-catalyst, and the molar ratio of the main catalyst to the co-catalyst is 1:500.

[0111] The present invention will be described in detail below with reference to the embodiments.

[0112] Example 1 A synthetic route for a constrained configuration metallocene compound, wherein the molecular formula of the complex C1 is: [(η 5 -C5H4)(CH(Ph)N(t-Bu)]TiCl2.

[0113] The synthetic route of complex C1 is as follows:

[0114]

[0115] The specific preparation process of complex C1 is as follows:

[0116] (1) Synthesis of N-tert-butylbenzaldehyde imine

[0117]

[0118] 4244 mg (about 40 mmol) of benzaldehyde was dissolved in 50 mL of dry DCM, and 380 mg (about 2 mmol) of TsOH (p-toluenesulfonic acid) was added as a catalyst. After the reaction flask was cooled to 0°C in an ice-water bath, 11702 mg (160 mmol) of tert-butylamine was added dropwise to the reaction system. A white solid was immediately formed. The ice-water bath was removed and the reaction was heated under reflux with stirring for 4 hours before stopping the reaction. After cooling, the pH value was adjusted to neutral with acetic acid. Low-boiling substances such as DCM and tert-butylamine were removed by rotary evaporation. A small amount of DCM was then added and filtered to obtain a white solid product. After drying, it weighed 2850 mg, with a yield of about 44.5%.

[0119] (2) Synthesis of ligand 1-a

[0120]

[0121] Weigh 1612 mg (about 10 mmol) of N-tert-butylbenzaldehyde imine into a reaction flask under argon atmosphere, add 30 mL of dry THF to mix well, cool the reaction system to about -20°C in an ice-salt bath, and continue stirring.

[0122] After purging all air with a pre-dried polytetrafluoroethylene tube, add an equal amount of cyclopentadienyllithium / THF solution dropwise into the bottle containing N-tert-butylbenzaldehyde imine / THF using argon pressure differential. After all the solution is added, wash the cyclopentadienyllithium reaction bottle with 10 mL of dry THF and add the solution together.

[0123] After the above operation is completed, the ice-salt bath is removed and the mixture is allowed to return to room temperature (25°C). Then, argon gas is filled with positive pressure and stirred for 12 hours. The reaction system gradually changes from turbid to light yellow and clear. During the reaction, a small amount of white solid appears after 8 hours, making the mixture appear as a suspension.

[0124] (3) Synthesis of ligand 1-b

[0125]

[0126] The generated compound 1-a was directly cooled to -78°C using a liquid nitrogen acetone bath under an argon atmosphere, and 4.4 mL (ie 1.1 eq) of 2.5 mmol / mL n The BuLi / n-Hexane solution was added dropwise to the compound 1-a / THF reaction mixture. The liquid nitrogen and acetone bath was then removed and the mixture was allowed to return to room temperature before being heated to 50°C. During this time, a large amount of white solid was observed to form. A moderate excess of butyl lithium was used to ensure complete reaction.

[0127] After returning to room temperature, the reaction system was filled with argon and stirred under reflux for 12 hours, with internal pressure checked periodically to ensure the reaction system was free of water and oxygen. Upon heating, the amount of insoluble solids increased, and the reaction solution changed from a turbid white to a light yellow or light brick-red turbidity. After 12 hours of reaction, the reaction was stopped and allowed to cool to room temperature. Most of the low-boiling point substances were removed in a room temperature water bath, leaving a small amount of THF solvent to dissolve unreacted compound 1-a and other lithium salts for easy purification. 40 mL of n-Hex was added, mixed thoroughly, and allowed to stand for 3 hours. The supernatant was removed by filter press and further purified by washing with a small amount of n-hexane. 30 mL of dry THF was then added to form a solution. n-Hexane is n-hexane.

[0128] (4) Synthesis of Compound C1

[0129]

[0130] After the argon gas was filled with positive pressure, the ligand 1-b / THF was cooled to -78°C using a liquid nitrogen acetone bath, and the pre-coordinated TiCl4·2THF (11 mmol) was dropped into the compound 1-b / THF through a previously dried polytetrafluoroethylene tube under argon, and then washed with 10 mL of dry THF and pressed in together.

[0131] Remove the liquid nitrogen-acetone bath, return to room temperature, and react for 12 hours. After completion, drain the reaction system, add 50 mL of dry toluene to fully dissolve the solution, stir, and let it stand for 6 hours. After removing the LiCl by filter press, remove approximately 30 mL of toluene (no solid precipitation should occur). Add dry n-Hex as a poor solvent along the wall of the reaction flask and allow it to diffuse spontaneously to recrystallize. Approximately 2405 mg of a black metallic solid was obtained, with an overall isolated yield of approximately 70%.

[0132] 1 H NMR (400MHz, C6D6) δ7.10(s,5H),7.02(s,2H),6.98(s,2H),3.21(s,1H),1.43(s,9H). 13 C NMR (151MHz, C6D6) δ138.33(s), 129.77(s), 126.13(s), 123.76(s), 120.28(s), 70.40(s), 45.34(s), 26.00(s).

[0133] MALDI-MS (laser 355 nm, frequency 200 Hz, matrix DHB): M{([η 5 -C5H5-PhCH-N- n Bu]TiCl2)×H +}=344.9683. M{([η 5 -C5H5-PhCH-NC(CH3)2]TiCl2) +}=328.9864.

[0134] Example 2 A synthetic route for a constrained configuration metallocene compound, wherein the molecular formula of the complex C3 is: [(η 5 -[Me4C5)CH(Ph)N(t-Bu)]TiCl2.

[0135] The synthetic route of complex C3 is as follows:

[0136]

[0137] (1) Synthesis of N-tert-butylbenzaldehyde imine

[0138] Same as Example 1.

[0139] (2) Synthesis of ligand 3-a

[0140]

[0141] Add 1612 mg (approximately 10 mmol) of N-tert-butylbenzaldehyde imine and 20 mL of THF to a 100 mL Schlenk flask. Lower the temperature to -78°C in a liquid nitrogen / acetone bath. Pressurize lithium tetramethylcyclopentadienyl / THF into the N-tert-butylbenzaldehyde imine / THF using a dry Teflon tube, then rinse with 10 mL of THF. After the addition is complete, remove the liquid nitrogen / acetone bath and allow the reaction to proceed at room temperature for 12 hours to yield a white solid.

[0142] (3) Synthesis of ligand 3-b

[0143]

[0144] Add 30 mL of dry n-hexane to 3-a and mix thoroughly. Let it stand for 12 hours and then filter. Remove the supernatant and wash with a small amount of dry n-hexane. Finally, add 30 mL of dry THF. Cool in a liquid nitrogen acetone bath and then add 10 mmol of n After the addition of BuLi to n-hexane solution, remove the cooling equipment and wait for it to return to room temperature. After positive pressure, transfer it to a 50°C oil bath and react overnight. After cooling to room temperature, remove the THF solvent and unreacted n BuLi and other impurities were removed by adding 40 mL of dry n-hexane and ultrasonicating to ensure uniform mixing. After standing for 3 h, the filtrate was removed by filter press, and 40 mL of dry THF was added to the white dilithium salt residue to prepare a suspension.

[0145] (4) Synthesis of complex C3

[0146]

[0147] A THF suspension of ligand 3-b was cooled in a liquid nitrogen-acetone bath. TiCl₄·2THF was then added dropwise to the reaction flask through a dry Teflon tube, washed with an appropriate amount of dry THF, and added simultaneously. After completion, the liquid nitrogen-acetone bath was removed and the reaction was allowed to proceed at room temperature for 12 h. After the reaction was complete, the reaction system was drained, 50 mL of dry toluene was added, stirred thoroughly to dissolve, and allowed to stand for 6 h. After insoluble matter had completely settled to the bottom of the flask, impurities such as LiCl were removed by filtration, and the residue was washed with a small amount of dry toluene. The reaction system was concentrated to approximately half the total volume of solvent. While the solution remained clear, 30 mL of dry n-Hex was slowly added along the wall to allow separation. After slow diffusion, the solid recrystallized to yield a black metallic solid. After filtration and draining, the tube was sealed and stored for subsequent polymerization. 2700 mg of the solid was obtained, yielding approximately 68.16%.

[0148] H NMR (400MHz, CD2Cl2) δ7.79 (d, J = 0.9Hz, 5H), 4.80 (s, 1H), 3.73 (s, 6H), 3.35 (t, J = 6.8Hz, 6H), 2.55 (s, 9H). 13 C NMR(151MHz, CDCl3)δ139.17(s),137.98(s),136.03(s),133.01(s),128.70(s) ),128.22(s),113.22(s),68.16(s),25.76(s),16.52(s),15.04(s),13.26(s).

[0149] Example 3 A synthetic route for a constrained configuration metallocene compound, wherein the molecular formula of the complex C4 is: [(η 5 -1-Ind)CH(Ph)N-Ada)]TiCl2.

[0150] The synthetic route of complex C4 is as follows:

[0151]

[0152] (1) Synthesis of N-adamantylbenzaldehyde imine

[0153]

[0154] To a 250 mL round-bottom flask, 190 mg (approximately 1 mmol) of TsOH (p-toluenesulfonic acid) as a catalyst, 15120 mg (approximately 100 mmol) of adamantaneamine, 2653 mg (approximately 25 mmol) of benzaldehyde, and 100 mL of toluene were added sequentially. The mixture was heated to reflux, with water removed through a water trap (the trap should be wrapped with asbestos cloth for insulation), and allowed to react for 18 hours. After the reaction, the mixture was cooled, the pH was adjusted to neutral with acetic acid, and most of the solvent was removed by rotary evaporation. A small amount of DCM was added to the mixture, and a white solid product precipitated. Filtering afforded 5383 mg of a white solid, with an isolated yield of 89.96%.

[0155] The results of NMR characterization are: 1 H NMR (400MHz, DMSO) δ7.87 (d, J = 6.7 Hz, 1H), 7.33 (d, J = 7.4 Hz, 1H), 2.05 (s, 1H), 1.76 (s, 2H), 1.60 (dd, J = 31.2, 11.6 Hz, 2H).

[0156] (2) Synthesis of ligand 4-a

[0157]

[0158] To a 100 mL Schlenk flask, add 2394 mg (approximately 10 mmol) of N-adamantylbenzaldehyde imine and 30 mL of dry THF. Place in a liquid nitrogen-acetone bath with constant stirring. Slowly press the previously prepared, clear, red indenyl lithium solution through a dry Teflon tube under an argon atmosphere. Wash with a small amount of dry THF and add the same to the reaction system. Maintain the temperature at -78°C. After the addition of the ingredients is complete, transfer the reaction system to room temperature and allow it to return to room temperature (25°C) for 12 hours. A large amount of light pink precipitate is visible at the end of the reaction.

[0159] (3) Synthesis of ligand 4-b

[0160]

[0161] The ligand 4-a after the reaction was completely drained to remove low-boiling impurities, and 35 mL of dry n-hexane was added and ultrasonically mixed. After standing for 5 hours to allow the monolithium salt to precipitate completely, it was filtered and washed with a small amount of dry n-hexane to remove low-polarity impurities. Then 30 mL of dry THF was added and mixed with the monolithium salt. In a liquid nitrogen acetone bath, under argon protection, 4.4 mL (about 11 mmol, i.e. 1.1 eq) of n BuLi solution was added dropwise to the reaction system. After 30 min, the low-temperature device was removed and the system was refluxed for 10 h after returning to room temperature.

[0162] (4) Synthesis of complex C4

[0163]

[0164] Ligand 4-b was mixed with 30 mL of dry n-hexane. After standing for 5 hours, the mixture was filtered to remove n-hexane-soluble impurities and byproducts. After washing, an appropriate amount of dry THF was added to disperse the dilithium salt. A metal preformulation, TiCl4·2THF, was prepared between filter presses and slowly pressed into the stirred dilithium salt at -78°C. The preformulation was then washed with 15 mL of dry THF and pressed into the mixture. The reaction system was allowed to return to room temperature and allowed to react for 12 hours. After completion of the reaction, the system was drained and 50 mL of dry toluene was added to fully dissolve the mixture with stirring. The mixture was allowed to stand overnight. The LiCl was removed by filtration, and the mixture was stored in the dark for two days to yield yellow clustered crystals. Approximately 2544 mg of yellow crystals were weighed, resulting in an overall isolated yield of approximately 53.89%.

[0165] The results of NMR characterization are: 1 H NMR (400MHz, CD2Cl2) δ7.44 (m, J = 7.4Hz, 2H), 7.15 (m, J = 7.5Hz, 4H), 7.06 (m, 5H), 4.04 (s, 1H), 2.24 (s, 6H), 1.96 (m, J = 14.3Hz, 6H), 1.58 (s, 3H).13 CNMR(101MHz,CD2Cl2)δ175.86(s),137.96(s),134.72(s),131.23(s),130.91(s),129.19(s),129.04( s),128.97(s),128.77(s),128.16(s),125.24(s),75.78(s),40.97(s),35.06(s),29.18(s),25.67(s).

[0166] MALDI-MS (laser 355 nm, frequency 200 Hz, matrix DHB): M{[η 5 -C9H6-PhCH-N-adamantane]TiCl2×Na + )=494.4911.

[0167] Example 4 A synthetic route for a constrained configuration metallocene compound, wherein the molecular formula of the complex C5 is: [(η 5 -Me4C5)CH(Ph)N-Ada)]ZrCl2.

[0168] The synthetic route of complex C5 is as follows:

[0169]

[0170] (1) Synthesis of N-adamantylbenzaldehyde imine

[0171] Same as step (1) in Example 3.

[0172] (2) Synthesis of ligand 5-a

[0173] To a 100 mL Schlenk flask, add 2394 mg (approximately 10 mmol) of N-adamantylbenzaldehyde imine and 30 mL of dry THF. Place in a liquid nitrogen-acetone bath. Using a dry Teflon tube, add the tetramethylcyclopentadienyllithium / THF suspension dropwise to the reaction system. Wash with a small amount of dry THF, which is then added simultaneously. After the addition is complete, remove the heat preservation device, allow the mixture to return to room temperature, then fill with argon. Stir the reaction at room temperature for 12 h to yield a white precipitate.

[0174] (3) Synthesis of ligand 5-b

[0175]

[0176] In a liquid nitrogen acetone bath, 11 mmol (ie 1.1 eq) of nThe n-hexane solution of BuLi forms a dilithium salt structure. After the addition is complete, the mixture is returned to room temperature and stirred under reflux for 20 hours. After the reaction is complete, it is cooled to room temperature. After removing most of the THF and low-boiling impurities, 30 mL of dry n-hexane is added and mixed thoroughly to dissolve the impurities. After standing for 5 hours, the liquid portion is removed by filter press. After washing with a small amount of dry n-hexane, 30 mL of dry THF is added to the pale yellow residue, compound 5-b, to prepare for subsequent metal complexation.

[0177] (4) Synthesis of Complex C5

[0178]

[0179] At -78°C, the clarified ZrCl4·2THF solution was added dropwise to 5-b through a dry Teflon tube. The solution was then washed with a small amount of dry THF and added to the reaction system. The reaction was stirred at room temperature for 12 hours. After the reaction, the reaction system was drained and 70 mL of dry DCM was added to completely dissolve catalyst C5. The solution was allowed to stand for complete precipitation of the LiCl. The LiCl was removed by filtration, and the residue was washed with a small amount of dry DCM and combined with the filtrate. Dry n-hexane was added dropwise until a large amount of bright yellow precipitate appeared. The solution was allowed to stand overnight for complete precipitation. The next day, the supernatant was removed by filtration, and the residue was washed with dry n-hexane and drained to yield 3210 mg of catalyst C5, resulting in an overall isolated yield of approximately 61.2%.

[0180] The results of NMR characterization are: 1 H NMR (600MHz, CD2Cl2) δ5.76(s,3H),5.24(m,2H),3.60(s,1H),1.90(s,12H),1.86(s,15H). 13 C NMR (151MHz, CD2Cl2) δ131.09(s), 122.49(s), 111.62(s), 27.13(s), 15.19(s), 13.35(s).

[0181] MALDI-MS (laser 355 nm, frequency 200 Hz, matrix DHB): M{([η 5 -Me4C5H-PhCH-N-adatanmane]ZrCl2) + )=510.1048.

[0182] Example 5 A synthetic route for a constrained configuration metallocene compound, wherein the molecular formula of the complex C6 is: [(η 5 -Ind-1-)CH(Ph)N-Ada)]ZrCl2.

[0183] The synthetic route of complex C6 is as follows:

[0184]

[0185] (1)-(3) Synthesis of Ligand 4-b

[0186] Same as steps (1)-(3) of Example 3.

[0187] (4) Synthesis of complex C6

[0188] 30 mL of dry THF was added, and the mixture was cooled in a liquid nitrogen / acetone bath. Using a dry Teflon tube, ZrCl4·2THF was slowly injected into compound 4-b / THF, followed by a small amount of dry THF for washing and injection into the reaction system. After the addition was complete, the reaction was continued at room temperature for 12 h. Low-boiling substances were drained, and 50 mL of dry DCM was added to dissolve catalyst C6 as completely as possible. The mixture was allowed to stand for complete precipitation of the LiCl. The mixture was then filtered and washed with a small amount of dry DCM to remove insoluble matter. The filtrate was concentrated to 2 / 3 of its volume, and dry n-hexane (a poor solvent) was added dropwise with stirring until solids precipitated. A small amount of dry DCM was added to dissolve the solids completely, and stirring was stopped. The mixture was allowed to stand for recrystallization. After draining, 2892 mg of a white powder was obtained, resulting in an overall isolated yield of 56.08%.

[0189] The results of NMR characterization are: 1 H NMR (600MHz, CD2Cl2) δ8.21(d,J=7.6Hz,2H),7.99(d,J=7.4Hz,2H),7.50(m,3H),7.37(t, J=7.7Hz,2H),7.27(t,J=7.4Hz,2H),3.49(s,1H),2.11(s,3H),1.89(d,6H),1.79(s,6H).

[0190] MALDI-MS (laser 355 nm, frequency 200 Hz, matrix DHB): M{[η 5 -C9H6-PhCH-N-adamantane]ZrCl2×H +}=513.9684.

[0191] Test Example 1 Application of catalysts in ethylene polymerization

[0192] The complex obtained in Examples 1-5 above was used as a catalyst to catalyze ethylene polymerization, comprising the following steps:

[0193] The polymerization reaction was carried out in a 100 mL dry stainless steel autoclave, which was heated at 120°C under vacuum for 30 minutes and then cooled to the desired temperature under an ethylene atmosphere. An appropriate amount of MAO (10% toluene solution) and toluene were added to the reactor, which was then saturated with ethylene for 10 minutes. After reaching a constant temperature, the catalyst toluene solution was added to the reactor, and ethylene at the desired pressure was introduced to initiate polymerization. After stirring the reaction mixture for the desired reaction time, the ethylene pressure in the autoclave was slowly discharged, and then 10 mL of ethanol was added dropwise to terminate the polymerization. The resulting mixture was poured into 50 mL of a 10% HCl solution in ethanol. The resulting polymer product was collected by filtration, washed with a 10% HCl solution in ethanol, and then vacuum dried at 65°C for 10 hours to constant weight, and the polymer mass was weighed. The polymerization results are shown in Table 1.

[0194] Table 1 Catalytic ethylene polymerization results

[0195]

[0196] Note: The general conditions for polymerization are ethylene pressure of 1.0 MPa (continuously fed during the polymerization reaction), catalyst concentration of 0.10 μmol / mL, total reaction volume of 100 mL, t 聚合时间 =30 min. Mw, MWD are from GPC.

[0197] Test Example 2 Application of catalysts in ethylene copolymerization

[0198] The application of homogeneous catalytic copolymerization of ethylene and α-olefins comprises the following steps:

[0199] The polymerization reaction apparatus was processed in the same manner as above, and the catalyst used was the catalyst complex C5 prepared in Example 4.

[0200] The polymerization conditions for the copolymerization reaction were as follows: 6 mL of a 10% by weight MAO / toluene solution (i.e., Al / Zr = 1000) was added to a total volume of 100 mL. 8 mL (approximately 50 mmol) of octene was added as a comonomer. The mixture was then saturated with ethylene for 10 minutes. 10 μmol of catalyst was added, and the ethylene pressure was adjusted to 1 MPa. After stirring the reaction mixture for the desired reaction time, the ethylene pressure in the autoclave was slowly vented, and 20 mL of ethanol was added dropwise to terminate the polymerization. The resulting mixture was poured into 100 mL of a 10% HCl solution in ethanol. The resulting polymer product was collected by filtration, washed with a 10% HCl solution in ethanol, and then vacuum dried at 65°C for 10 hours to constant weight. The polymer mass was then weighed. The polymerization results are shown in Table 2.

[0201] Table 2 Results of complex C5 catalyzing ethylene-1-octene

[0202]

[0203]

[0204] Note: The general conditions for polymerization are ethylene pressure of 1 MPa (continuously introduced during the polymerization reaction), catalyst concentration of 0.10 μmol / mL, 1-octene concentration of 8%, total reaction volume of 100 mL, t 聚合时间 = 30min. The polymer was analyzed by DSC, GPC, 13 C NMR characterization. Tm, Tg, Xc are from DSC results, Mn, Mw, MWD are from GPC results. a Act. = 10 6 g / (mol·Zr·h); b obtained by fitting the density data obtained by DSC.

[0205] The results of polymerization and polymer properties are shown in Table 3 when the catalyst and octene concentrations in the polymerization system are changed.

[0206] Table 3 Results of ethylene-1-octene catalysis by complex C5 under different conditions

[0207]

[0208] Note: The general conditions for polymerization are ethylene pressure of 1 MPa (continuously fed during the polymerization reaction), polymerization temperature of 60°C, total volume of reaction solution of 100 mL, t 聚合时间 =30min. Al / Zr=1000, polymer was analyzed by DSC, GPC, 13 C NMR characterization. Tm, Tg, Xc are from DSC results, Mn, Mw, MWD are from GPC results. a Act. = 10 6 g / mol·Zr·h; b obtained by fitting the density data obtained by DSC; c Al / Zr=500; d Al / Zr=1500; e Al / Zr=2000

[0209] From the results of the above examples, it can be seen that the random insertion of 1-octene in the polymer leads to a significant decrease in crystallinity. As shown in Table 1, this type of catalyst can catalyze the polymerization of ethylene to obtain high molecular weight, narrow distribution polyethylene. As shown in Table 2, the catalyst synthesized by the present invention can catalyze the copolymerization of ethylene and 1-octene with high activity, and the 1-octene content in the copolymer can be controlled between 10-50w%. As shown in Table 3, the activity remains at 10 when the cocatalyst is reduced to 500 times. 6 g / mol·Zr·h, the polymer molecular weight, crystallinity and octene content in the polymer can be conveniently controlled between 10-50w%. The advantages of the present invention are obvious.

[0210] As described above, although the present invention has been shown and described with reference to specific preferred embodiments, it should not be construed as limiting the present invention itself. Various changes may be made to it in form and detail without departing from the spirit and scope of the present invention as defined in the appended claims.

Claims

1. A method for preparing a restricted configuration metallocene compound, comprising the following steps: (1) under the protection of inert gas or nitrogen, with an organic acid as a catalyst, an amine compound, an aldehyde ketone compound, and a first solvent are added to a reactor, heated to reflux for a first reaction, cooled, adjusted to a neutral pH, and then rotary evaporated, and then a polar solvent is added, filtered, to obtain an imine compound; wherein, The aldehyde and ketone compounds are aldehyde compounds or ketone compounds; (2) under the protection of inert gas or nitrogen, at a temperature of -78 to 0°C, adding an ether solution to the above-mentioned imine compound, then mixing with any one of cyclopentadienyl lithium, tetramethylcyclopentadienyl lithium or indenyl lithium, and heating to room temperature to carry out a second reaction to obtain ligand a; (3) under the protection of inert gas or nitrogen, at a temperature of -78 to 0°C, the ligand a is mixed with an alkyl lithium, heated to reflux, and then subjected to a third reaction to obtain a ligand b; (4) under the protection of inert gas or nitrogen, at a temperature of -78 to 0°C, the ligand b is mixed with MCl4·organic complexing agent, heated to room temperature, and then subjected to a fourth reaction, followed by recrystallization and separation to obtain a product; wherein, in the MCl4·organic complexing agent: MCl4 is selected from one of TiCl4 and ZrCl4; the organic complexing agent is tetrahydrofuran, diethyl ether or N,N,N,N-tetramethylethylenediamine; The restricted configuration metallocene compound has a structure as shown in the following formula: Formula (I) or Formula (II); in, R1, R2 are independently selected from hydrogen, methyl, ethyl, C3-C6 alkyl or aromatic groups; R3 is independently selected from methyl, ethyl, C3-C6 alkyl, aryl or adamantyl; R4-R7 are independently selected from hydrogen or methyl; M is independently selected from titanium or zirconium.

2. The preparation method according to claim 1, characterized in that: R4-R7 are each independently selected from methyl.

3. The preparation method according to claim 1, characterized in that: The chemical formula of the compound is as follows: [( η 5 -Me4C5)C(Me)2N(t-Bu)]TiCl2、 [( η 5 -C5H4) CH(Ph)N (t-Bu)]TiCl2、 [( η 5 -Me4C5)CH(Ph)N(t-Bu)]TiCl2、 [( η 5 - 1-Ind)CH(Ph)N-Ada)]TiCl2、 [( η 5 - Me4C5)CH(Ph)N-Ada)] ZrCl2、 [( η 5 - Ind-1)CH(Ph)N-Ada)]ZrCl2 or[( η 5 - Me4C5)C(Ph)2N-Ada)] ZrCl2.

4. The preparation method according to claim 1, characterized in that: In step (1), the amine compound is methylamine, tert-butylamine, aniline or adamantaneamine; In step (1), the organic acid catalyst is at least one of p-toluenesulfonic acid, benzenesulfonic acid, trifluorosulfonic acid, and methanesulfonic acid; In step (1), the molar ratio of the amine compound to the aldehyde and ketone compound is 4-5.

5. The preparation method according to claim 4, characterized in that: In step (1), the aldehyde and ketone compound is benzaldehyde, acetone, butanone, acetaldehyde or benzophenone.

6. The preparation method according to claim 1, characterized in that: In step (2), the molar ratio of the imine compound to cyclopentadienyl lithium, tetramethylcyclopentadienyl lithium or indenyl lithium is 1:1; In step (2), the ether solution includes at least one of diethyl ether solution, anisole solution, and tetrahydrofuran solution.

7. The preparation method according to claim 1, characterized in that: In step (3), the alkyl lithium is methyl lithium, ethyl lithium, n-butyl lithium or tert-butyl lithium; In step (3), the molar ratio of ligand a to alkyl lithium is 1:1-3.

8. The preparation method according to claim 7, characterized in that: In step (3), the alkyl lithium is butyl lithium; In step (3), the molar ratio of ligand a to alkyl lithium is 1:

1.

9. The preparation method according to claim 1, characterized in that: In step (4), the molar ratio of ligand b to MCl4 is (0.9~1.5):

1.

10. The preparation method according to claim 9, characterized in that: In step (4), the organic complexing agent is tetrahydrofuran.

Images