A method for the synthesis of a non-bridged metallocene catalyst

Abstract

This invention provides a method for obtaining cyclopentadiene or its derivative anions by reacting ionic liquids with elemental sodium or potassium to produce cyclopentadiene or its derivative anions, reducing synthesis steps and reaction energy consumption. Compared to conventional methods for obtaining cyclopentadiene monomers or their derivative anions from cyclopentadiene dimers or substituted cyclopentadiene dimers, the method of this invention offers significantly milder reaction conditions.

Description

Technical Field

[0001] This invention belongs to the field of organic synthesis, specifically relating to a method for synthesizing a non-bridged metallocene catalyst. Background Technology

[0002] Metallocene catalysts have a single active center, high catalyst activity, and good copolymerization performance. The molecular weight and molecular weight distribution of the polymers obtained by their catalysis can be controlled by changing the ligand structure, and therefore have always attracted widespread attention.

[0003] Non-bridged metallocene compounds are compounds formed by the direct bonding of one or two cyclopentadienyl (or fluorenyl, or indene) groups or their derivatives with transition metal atoms. Various substituents can be present on the cyclopentadienyl (indene or fluorenyl) group. These catalysts are most commonly found with the Cp2MX2 structure (Cp is cyclopentadienyl (fluorenyl, or indene); M is Ti, Zr, Hf; X is Cl, Br, I), and have received considerable attention in olefin polymerization research. Numerous studies have reported their synthesis methods, primarily involving the reaction of 1 equivalent of a cyclopentadiene or its derivative anion with 0.5 equivalents of MX4. Based on different synthetic methods for cyclopentadiene or its derivative anions, they are mainly divided into the following two categories:

[0004] The first type involves pre-depolymerizing cyclopentadiene dimers at high temperatures to obtain cyclopentadiene monomers, which then react with elemental metals such as sodium and potassium (CN101074239 A, CN101735280 A), alkyl lithium reagents (CN1131953A), Grignard reagents (CN102844284A, US6175027 A), hydrides such as sodium hydride (US6046346A), or alkali metal hydroxides such as sodium hydroxide (US5336795A) to generate cyclopentadienyl anions. To obtain substituted cyclopentadienyl anions, it is necessary to first react with halogenated hydrocarbons to generate substituted cyclopentadienes before reacting with the above-mentioned anionizing reagents to generate substituted cyclopentadienyl anions.

[0005] Category 2: Cyclopentadiene and its derivative anions are obtained by reacting cyclopentadiene dimers or substituted cyclopentadiene dimers with metallic elements such as sodium and potassium at high temperatures (US2942040A, CN105646197 A).

[0006] The above-mentioned routes for synthesizing Cp2MX2 all have significant drawbacks: First, the first type involves more synthetic steps and is more complex than the second (for example, the cyclopentadiene monomer needs to be pre-depolymerized; the substituted cyclopentadiene requires further purification after formation). Furthermore, cyclopentadiene or substituted cyclopentadiene monomers are unstable during storage and readily form dimers via intermolecular Diels-Alder reactions, requiring significant effort to remove the dimers before reuse. Second, the depolymerization of cyclopentadiene dimers or substituted cyclopentadiene dimers in both types requires high temperatures of around 170 degrees Celsius, significantly increasing the cost and difficulty of catalyst synthesis. Therefore, improving the above reactions to reduce synthetic steps, lower reaction energy consumption, and increase economic efficiency is particularly important. Summary of the Invention

[0007] To address the aforementioned problems in the prior art, this invention provides a method for obtaining cyclopentadiene or its derivative anions by reacting ionic liquids with cyclopentadiene dimers or substituted cyclopentadiene dimers with elemental sodium or potassium, thereby reducing synthesis steps and lowering reaction energy consumption. Ionic liquids (ILs) are liquid compounds composed of inorganic or organic anions and cations at temperatures close to room temperature. They possess good solubility, thermal stability, and electrical conductivity.

[0008] The technical solution of the present invention is as follows:

[0009] A method for synthesizing a non-bridged metallocene catalyst Cp2MX2 includes the following steps:

[0010] 1) Under an inert gas atmosphere, the cyclopentadiene dimer or substituted cyclopentadiene dimer shown in Formula I is reacted in an ether solvent at 50-100°C in the presence of metallic sodium or potassium and ionic liquid.

[0011] 2) Cool the reaction system to 0-40℃ to remove unreacted sodium or potassium, add MX4 to the filtrate and react at -20-20℃ to obtain the target product Cp2MX2;

[0012]

[0013] Wherein, R is a monosubstituted or polysubstituted group selected from H, C 1-12 Alkyl, Halogenated C 1-12 Alkyl, C 1-12 Alkoxy, C 3-20 Cycloalkyl, 3-20 membered heterocyclic groups, C 6-20 Aryl, 5-20 heteroaryl, C 6-20 Aryl benzo[C] 3-20 cycloalkyl, C 6-20 aryl 3-20 membered heterocyclic, 5-20 membered heteroaryl 3-20 membered C 3-20Cycloalkyl or 5-20-membered heteroaryl and 3-20-membered heterocyclic;

[0014] The ionic liquid is any one of L1-L20;

[0015] M is any one of Ti, Zr, and Hf; X is any one of Cl, Br, and I;

[0016] The ether solvent is any one of diethyl ether, tetrahydrofuran, and ethylene glycol dimethyl ether;

[0017] L1 is L2

[0018] L3 is L4 is

[0019] L5 is L6 is

[0020] L7 is L8 is

[0021] L9 is L10 is

[0022] L11 is L12 is

[0023] L13 is L14 is

[0024] L15 is L16 is

[0025] L17 is L18 is

[0026] L19 is L20 is

[0027] Where Ph is phenyl and Bu is n-butyl.

[0028] According to an embodiment of the present invention, the inert gas atmosphere is a nitrogen atmosphere.

[0029] According to embodiments of the present invention, R is a monosubstituted or polysubstituted group selected from H, C 1-6 Alkyl, Halogenated C 1-6 Alkyl, C 1-6 Alkoxy, C 3-12 Cycloalkyl, 3-12 membered heterocyclic groups, C6-12 Aryl or 5-20 heteroaryl compounds.

[0030] According to embodiments of the present invention, R is a monosubstituted or polysubstituted group, selected from H or C. 1-6 alkyl.

[0031] In some specific embodiments of the present invention, the substituted cyclopentadiene dimer is selected from n-butylcyclopentadiene dimer or 1-butyl-3-methyl-cyclopentadiene dimer.

[0032] According to an embodiment of the present invention, in step 1), the reaction continues until no more gas is generated.

[0033] According to an embodiment of the present invention, the reaction temperature in step 1) is 60-90°C, for example 70-80°C.

[0034] According to an embodiment of the present invention, the reactants are used in the following amounts: 1.0 eq of cyclopentadiene dimer or substituted cyclopentadiene dimer, 2.0-4.0 eq of sodium or potassium, 0.05-0.2 eq of ionic liquid, and 1.0 eq of ether solvent to achieve a dimer concentration of 0.5 M-2 M in the system and 1.0 eq of MX4.

[0035] According to an embodiment of the present invention, the reaction temperature in step 2) is -10 to 10°C.

[0036] Beneficial effects

[0037] 1. This invention combines the depolymerization process of cyclopentadiene dimer or substituted cyclopentadiene dimer with the anionization process of cyclopentadiene monomer or its derivative in one step, directly reacting with MX4 to prepare metallocene catalyst without complex purification steps, which greatly shortens the synthesis steps and reduces its production cost.

[0038] 2. Compared with the previous process of obtaining anions of cyclopentadiene monomers or their derivatives from cyclopentadiene dimers or substituted cyclopentadiene dimers, the method of the present invention has significantly milder reaction conditions.

[0039] Terminology Definitions and Explanations

[0040] Term "C" 1-12 "alkyl" should be understood to refer to a straight-chain or branched saturated monovalent hydrocarbon group having 1 to 12 carbon atoms, preferably C12. 1-6 Alkyl group. "C" 1-6"alkyl" should be understood to preferably represent a straight-chain or branched saturated monovalent hydrocarbon group having 1, 2, 3, 4, 5, or 6 carbon atoms. The alkyl group is, for example, methyl, ethyl, propyl, butyl, pentyl, hexyl, isopropyl, isobutyl, sec-butyl, tert-butyl, isopentyl, 2-methylbutyl, 1-methylbutyl, 1-ethylpropyl, 1,2-dimethylpropyl, neopentyl, 1,1-dimethylpropyl, 4-methylpentyl, 3-methylpentyl, 2-methylpentyl, 1-methylpentyl, 2-ethylbutyl, 1-ethylbutyl, 3,3-dimethylbutyl, 2,2-dimethylbutyl, 1,1-dimethylbutyl, 2,3-dimethylbutyl, 1,3-dimethylbutyl, or 1,2-dimethylbutyl, or their isomers. In particular, the group has 1, 2, or 3 carbon atoms ("C..."). 1-3 Alkyl), such as methyl, ethyl, n-propyl or isopropyl.

[0041] Term "C" 3-20 "Cycloalkyl" should be understood as representing a saturated monovalent monocyclic, bicyclic, or polycyclic hydrocarbon ring (also called a fused ring hydrocarbon ring) with 3-20 carbon atoms. Bicyclic or polycyclic cycloalkyl includes fused cycloalkyl, bridged cycloalkyl, and spirocyclic cycloalkyl; fused ring refers to a fused ring structure formed by two or more cyclic structures sharing two adjacent ring atoms (i.e., sharing a bond). Bridged ring refers to a fused ring structure formed by two or more cyclic structures sharing two non-adjacent ring atoms. Spirocyclic refers to a fused ring structure formed by two or more cyclic structures sharing a single ring atom. For example, the C 3-20 Cycloalkyl groups can be C 3-8 Monocyclic cycloalkyl groups, such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, or C 7-12 And cycloalkyl groups, such as decahydronaphthalene rings.

[0042] The term "3-20 membered heterocyclic group" refers to a saturated monovalent monocyclic or bicyclic hydrocarbon ring containing 1-5 heteroatoms independently selected from N, O, and S, preferably a "3-12 membered heterocyclic group". The term "3-12 membered heterocyclic group" refers to a saturated monovalent monocyclic or bicyclic hydrocarbon ring containing 1-5, preferably 1-3, heteroatoms selected from N, O, and S. The heterocyclic group can be connected to the rest of the molecule via any one of the carbon atoms or a nitrogen atom (if present). Specifically, the heterocyclic group can include, but is not limited to: 4-membered rings, such as azirrobutyl or oxobutyl; 5-membered rings, such as tetrahydrofuranyl, dioxacyclopentenyl, pyrrolyl, imidazoalkyl, pyrazolyl, or pyrrololinyl; or 6-membered rings, such as tetrahydropyranyl, piperidinyl, morpholinyl, dithiaalkyl, thiomorpholinyl, piperazinyl, or trithiaalkyl; or 7-membered rings, such as diazacycloheptyl. Optionally, the heterocyclic group may be benzo-fused. The heterocyclic group may be bicyclic, for example, but not limited to, a 5,5-membered ring, such as a hexahydrocyclopentano[c]pyrrole-2(1H)-yl ring, or a 5,6-membered bicyclic ring, such as a hexahydropyrrolo[1,2-a]pyrazin-2(1H)-yl ring. The nitrogen-containing ring may be partially unsaturated, i.e., it may contain one or more double bonds, for example, but not limited to, 2,5-dihydro-1H-pyrrole, 4H-[1,3,4]thiadiazinyl, 4,5-dihydrooxazolyl, or 4H-[1,4]thiazinyl, or it may be benzo-fused, for example, but not limited to, dihydroisoquinolinyl. According to the invention, the heterocyclic group is non-aromatic.

[0043] Term "C" 6-20 "Aryl" should be understood as representing a monocyclic, bicyclic, or tricyclic hydrocarbon ring with 6 to 20 carbon atoms that is monovalent and partially aromatic, preferably "C". 6-14 Aryl. The term "C" 6-14 "Aryl" should preferably be understood to represent a monovalent aromatic or partially aromatic monocyclic, bicyclic, or tricyclic hydrocarbon ring ("C") having 6, 7, 8, 9, 10, 11, or 12 carbon atoms. 6-14 Aryl), particularly a ring with 6 carbon atoms (“C6 aryl”), such as phenyl; or biphenyl, or a ring with 9 carbon atoms (“C9 aryl”), such as indenyl or indenyl, or a ring with 10 carbon atoms (“C9 aryl”). 10 Aryl groups, such as tetrahydronaphthyl, dihydronaphthyl, or naphthyl, or rings with 13 carbon atoms (“C”). 13 Aryl groups, such as fluorene groups, or rings with 14 carbon atoms (“C”). 14 Aryl), for example, anthracene.

[0044] The term "5-20-membered heteroaryl" should be understood to include monovalent monocyclic, bicyclic, or tricyclic aromatic ring systems having 5 to 20 ring atoms and containing 1 to 5 heteroatoms independently selected from N, O, and S, such as "5-12-membered heteroaryl". The term "5-12-membered heteroaryl" should also be understood to include monovalent monocyclic, bicyclic, or tricyclic aromatic ring systems having 5, 6, 7, 8, 9, 10, 11, or 12 ring atoms, particularly 5, 6, 9, or 10 carbon atoms, and containing 1 to 5, preferably 1 to 3, heteroatoms independently selected from N, O, and S, and in each case, may be benzofused. Specifically, the heteroaryl group is selected from thienyl, furanyl, pyrroleyl, oxazolyl, thiazolyl, imidazoleyl, pyrazolyl, isoxazolyl, isothiazolyl, oxadiazolyl, triazolyl, thiadiazolyl, thia-4H-pyrazolyl, and their benzo[derivatives], such as benzofuranyl, benzothienyl, benzooxazolyl, benzoisooxazolyl, benzoimidazolyl, benzotriazolyl, indazole, indolyl, isindolyl, etc.; or pyridyl, pyridazinyl, pyrimidinyl, pyrazinyl, triazinyl, and their benzo[derivatives], such as quinolinyl, quinazolinyl, isoquinolinyl, etc.; or acrylinyl, inazinyl, purinyl, and their benzo[derivatives]; or terpenolyl, phthalazinyl, quinazolinyl, quinoxolinyl, naphridinyl, pteridinyl, carbazolyl, acridineyl, phenazinyl, phenothiazinyl, phenothiazinyl, etc.

[0045] Unless otherwise stated, heterocyclic, heteroaryl, or heteroaryl groups include all their possible isomers, such as their positional isomers. Thus, for some illustrative, non-limiting examples, pyridyl or pyridylene includes pyridin-2-yl, pyridin-2-yl, pyridin-3-yl, pyridin-3-yl, pyridin-4-yl, and pyridin-4-yl; thiophenyl or thiophene includes thiophene-2-yl, thiophene-2-yl, thiophene-3-yl, and thiophene-3-yl.

[0046] The above refers to the term "C" 1-12 The definition of "alkyl" also applies to compounds containing "C". 1-12 Other terms for "alkyl", such as the term "C 1-12 Alkoxy, halogenated C 1-12 alkyl". Detailed Implementation

[0047] The technical solution of the present invention will be further described in detail below with reference to specific embodiments. It should be understood that the following embodiments are merely illustrative and explanatory of the present invention, and should not be construed as limiting the scope of protection of the present invention. All technologies implemented based on the above content of the present invention are covered within the scope of protection intended by the present invention.

[0048] Unless otherwise stated, the raw materials and reagents used in the following examples are commercially available products or can be prepared by known methods.

[0049] Example 1

[0050] This embodiment provides a method for preparing bis(cyclopentadienyl)zirconia, the specific preparation process of which is as follows:

[0051] A 250 mL three-necked flask was purged with nitrogen. 0.1 mol of cyclopentadiene dimer, 0.3 mol of sodium sand, 0.01 mol of ionic liquid L1, and 100 mL of tetrahydrofuran were added. The mixture was stirred at 70 °C until no gas was generated. After returning to room temperature, the solution was filtered and transferred to another dry 250 mL three-necked flask purged with nitrogen under a nitrogen atmosphere. The reaction flask was placed in an ethanol bath at -10 °C, stirred, and under nitrogen protection, 0.1 mol of ZrCl4 powder was added. The reaction was allowed to proceed for 12 hours. After the reaction was complete, the reaction system was dried under reduced pressure. Under a nitrogen atmosphere, a certain amount of toluene was added to dissolve the solid. The solution was filtered through a sintered glass funnel, and a large amount of n-hexane was added to the filtrate. The solid precipitated in an ethanol bath at -20 °C. The mother liquor was filtered off, and the solid was dried under vacuum to obtain the target product (the recrystallized system was relatively clean, and no other impurity peaks were found by NMR analysis), with a yield of 60%. 1 H NMR (400MHz, CDCl3) δ6.41 (s, 10H).

[0052] Example 2

[0053] This embodiment provides a method for preparing bis(cyclopentadienyl)zirconia, the specific preparation process of which is as follows:

[0054] A 250 mL three-necked flask was purged with nitrogen. 0.1 mol of cyclopentadiene dimer, 0.3 mol of sodium sand, 0.005 mol of ionic liquid L1, and 100 mL of tetrahydrofuran were added. The mixture was stirred at 80 °C until no gas was generated. After returning to room temperature, the solution was filtered and transferred to another dry 250 mL three-necked flask purged with nitrogen under a nitrogen atmosphere. The reaction flask was placed in an ethanol bath at -10 °C, stirred, and under nitrogen protection, 0.1 mol of ZrCl4 powder was added. The reaction was allowed to proceed for 12 hours. After the reaction was complete, the reaction system was dried under reduced pressure. Under a nitrogen atmosphere, a certain amount of toluene was added to dissolve the solid. The solution was filtered through a sintered glass funnel, and a large amount of n-hexane was added to the filtrate. The solid precipitated in an ethanol bath at -20 °C. The mother liquor was filtered off, and the solid was dried under vacuum to obtain the target product (the recrystallized system was relatively clean, and no other impurity peaks were found by NMR analysis), with a yield of 52%.

[0055] Example 3

[0056] This invention provides a method for preparing bis(cyclopentadienyl)zirconia, the specific preparation process of which is as follows:

[0057] A 250 mL three-necked flask was purged with nitrogen. 0.1 mol of cyclopentadiene dimer, 0.3 mol of sodium sand, 0.01 mol of ionic liquid L4, and 100 mL of ethylene glycol dimethyl ether were added. The mixture was stirred at 100 °C until no gas was generated. After returning to room temperature, the solution was filtered and transferred to another dry 250 mL three-necked flask purged with nitrogen under a nitrogen atmosphere. The reaction flask was placed in an ethanol bath at -10 °C, stirred, and under nitrogen protection, 0.1 mol of ZrCl4 powder was added. The reaction was allowed to proceed for 12 hours. After the reaction was complete, the reaction system was dried under reduced pressure. Under a nitrogen atmosphere, a certain amount of toluene was added to dissolve the solid. The solution was filtered through a sintered glass funnel, and a large amount of n-hexane was added to the filtrate. The solid precipitated in an ethanol bath at -20 °C. The mother liquor was filtered off, and the solid was dried under vacuum to obtain the target product (the recrystallized system was relatively clean, and no other impurity peaks were found by NMR analysis), with a yield of 55%.

[0058] Example 4

[0059] This embodiment provides a method for preparing bis(cyclopentadienyl)zirconia, the specific preparation process of which is as follows:

[0060] A 250 mL three-necked flask was purged with nitrogen. 0.1 mol of cyclopentadiene dimer, 0.2 mol of sodium sand, 0.02 mol of ionic liquid L6, and 100 mL of tetrahydrofuran were added. The mixture was stirred at 50 °C until no gas was generated. After returning to room temperature, the solution was filtered and transferred to another dry 250 mL three-necked flask purged with nitrogen under a nitrogen atmosphere. The reaction flask was placed in an ethanol bath at 20 °C, stirred, and under nitrogen protection, 0.1 mol of ZrCl4 powder was added. The reaction was allowed to proceed for 12 hours. After the reaction was complete, the reaction system was dried under reduced pressure. Under a nitrogen atmosphere, a certain amount of toluene was added to dissolve the solid. The solution was filtered through a sintered glass funnel, and a large amount of n-hexane was added to the filtrate. The solid precipitated in an ethanol bath at -20 °C. The mother liquor was filtered off, and the solid was dried under vacuum to obtain the target product (the recrystallized system was relatively clean, and no other impurity peaks were found by NMR analysis), with a yield of 40%.

[0061] Example 5

[0062] This embodiment provides a method for preparing bis(cyclopentadienyl)zirconia, the specific preparation process of which is as follows:

[0063] A 250 mL three-necked flask was purged with nitrogen. 0.1 mol of cyclopentadiene dimer, 0.3 mol of sodium sand, 0.01 mol of ionic liquid L10, and 100 mL of tetrahydrofuran were added. The mixture was stirred at 70 °C until no gas was generated. After returning to room temperature, the solution was filtered and transferred to another dry 250 mL three-necked flask purged with nitrogen under a nitrogen atmosphere. The reaction flask was placed in an ethanol bath at -20 °C, stirred, and under nitrogen protection, 0.1 mol of ZrCl4 powder was added. The reaction was allowed to proceed for 12 hours. After the reaction was complete, the reaction system was dried under reduced pressure. Under a nitrogen atmosphere, a certain amount of toluene was added to dissolve the solid. The solution was filtered through a sintered glass funnel, and a large amount of n-hexane was added to the filtrate. The solid precipitated in an ethanol bath at -20 °C. The mother liquor was filtered off, and the solid was dried under vacuum to obtain the target product (the recrystallized system was relatively clean, and no other impurity peaks were found by NMR analysis), with a yield of 48%.

[0064] Example 6

[0065] This embodiment provides a method for preparing bis(cyclopentadienyl)zirconium dibromide, and the specific preparation process is as follows:

[0066] A 250 mL three-necked flask was purged with nitrogen. 0.1 mol of cyclopentadiene dimer, 0.3 mol of sodium sand, 0.01 mol of ionic liquid L13, and 200 mL of tetrahydrofuran were added. The mixture was stirred at 70 °C until no gas was generated. After returning to room temperature, the solution was filtered and transferred to another dry 250 mL three-necked flask purged with nitrogen under a nitrogen atmosphere. The reaction flask was placed in an ethanol bath at -10 °C, stirred, and under nitrogen protection, 0.1 mol of ZrBr4 powder was added. The reaction was allowed to proceed for 12 hours. After the reaction was complete, the reaction system was dried under reduced pressure. Under a nitrogen atmosphere, a certain amount of toluene was added to dissolve the solid. The solution was filtered through a sintered glass funnel, and a large amount of n-hexane was added to the filtrate. The solid precipitated in an ethanol bath at -20 °C. The mother liquor was filtered off, and the solid was dried under vacuum to obtain the target product (the recrystallized system was relatively clean, and no other impurity peaks were found by NMR analysis), with a yield of 44%.

[0067] Example 7

[0068] This invention provides a method for preparing bis(cyclopentadienyl)titanium dichloride, the specific preparation process of which is as follows:

[0069] A 250 mL three-necked flask was purged with nitrogen. 0.1 mol of cyclopentadiene dimer, 0.3 mol of sodium sand, 0.01 mol of ionic liquid L17, and 100 mL of tetrahydrofuran were added. The mixture was stirred at 70 °C until no gas was generated. After returning to room temperature, the solution was filtered and transferred to another dry 250 mL three-necked flask purged with nitrogen under a nitrogen atmosphere. The reaction flask was placed in an ethanol bath at -10 °C, stirred, and under nitrogen protection, 0.1 mol of TiCl4 was added. The reaction was allowed to proceed for 12 hours. After the reaction was complete, the reaction system was dried under reduced pressure. Under a nitrogen atmosphere, a certain amount of toluene was added to dissolve the solid. The solution was filtered through a sintered glass funnel, and a large amount of n-hexane was added to the filtrate. The solid precipitated in an ethanol bath at -20 °C. The mother liquor was filtered off, and the solid was dried under vacuum to obtain the target product (the recrystallized system was relatively clean, and no other impurity peaks were found by NMR analysis), with a yield of 53%.

[0070] Example 8

[0071] This embodiment provides a method for preparing bis(n-butylcyclopentadienyl)zirconia, and the specific preparation process is as follows:

[0072] A 250 mL three-necked flask was purged with nitrogen. 0.1 mol of n-butylcyclopentadiene dimer, 0.3 mol of sodium sand, 0.01 mol of ionic liquid L5, and 100 mL of tetrahydrofuran were added. The mixture was stirred at 80 °C until no gas was generated. After returning to room temperature, the solution was filtered and transferred to another dry 250 mL three-necked flask purged with nitrogen under a nitrogen atmosphere. The reaction flask was placed in an ethanol bath at 0 °C, stirred, and under nitrogen protection, 0.1 mol of ZrCl4 powder was added. The reaction was allowed to proceed for 12 hours. After the reaction was complete, the reaction system was dried under reduced pressure. Under a nitrogen atmosphere, a certain amount of toluene was added to dissolve the solid. The solution was filtered through a sintered glass funnel, and a large amount of n-hexane was added to the filtrate. The solid precipitated in an ethanol bath at -20 °C. The mother liquor was filtered off, and the solid was dried under vacuum to obtain the target product (the recrystallized system was relatively clean, and no other impurity peaks were found by NMR analysis), with a yield of 50%. 1 H NMR (400MHz, CDCl3) δ6.29(t,J=2.6Hz,4H),6.20(t,J=2.6Hz,4H),2.63(t,J=7.92,4H),1.58–1.48(m,4H),1.40–1.29(m,4H),0.91(t,J=7.3Hz,6H).

[0073] Example 9

[0074] This embodiment provides a method for preparing bis(1-butyl-3-methylcyclopentadienyl)zirconia, the specific preparation process of which is as follows:

[0075] A 250 mL three-necked flask was purged with nitrogen. 0.1 mol of 1-butyl-3-methyl-cyclopentadiene dimer, 0.4 mol of sodium sand, 0.02 mol of ionic liquid L12, and 50 mL of tetrahydrofuran were added. The mixture was stirred at 80 °C until no gas was generated. After returning to room temperature, the solution was filtered and transferred to another dry 250 mL three-necked flask purged with nitrogen under a nitrogen atmosphere. The reaction flask was placed in an ethanol bath at 0 °C, stirred, and under nitrogen protection, 0.1 mol of ZrCl4 powder was added. The reaction was allowed to proceed for 12 hours. After the reaction was complete, the reaction system was dried under reduced pressure. Under a nitrogen atmosphere, a certain amount of toluene was added to dissolve the solid. The solution was filtered through a sintered glass funnel, and a large amount of n-hexane was added to the filtrate. The solid precipitated in an ethanol bath at -20 °C. The mother liquor was filtered off, and the solid was dried under vacuum to obtain the target product (the recrystallized system was relatively clean, and no other impurity peaks were found by NMR analysis), with a yield of 47%. 1 H NMR (400MHz, CDCl3) δ6.07(t,J=2.3Hz,2H),5.94(q,J=2.9Hz,2H),5.90(q,J=2.8Hz,2H),2.64–2.52(m,2 H),2.50–2.39(m,2H),2.20(d,J=1.9Hz,6H),1.57–1.39(m,4H),1.38–1.28(m,4H),0.91(t,J=7.3Hz,6H).

[0076] The embodiments of the present invention have been described above. However, the present invention is not limited to the above embodiments. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for the synthesis of a non-bridged metallocene catalyst Cp2MX2, characterized in that, Includes the following steps: 1) Under an inert gas atmosphere, the cyclopentadiene dimer or substituted cyclopentadiene dimer shown in Formula I is reacted in an ether solvent at 50-100°C in the presence of metallic sodium or potassium and ionic liquid. 2) Cool the reaction system to 0-40℃ to remove unreacted sodium or potassium, add MX4 to the filtrate and react at -20-20℃ to obtain the target product Cp2MX2; Wherein, R is a monosubstituted or polysubstituted group selected from H, C 1-12 Alkyl, Halogenated C 1-12 Alkyl or C 1-12 Alkoxy; The ionic liquid is any one of L1-L20; M is any one of Ti, Zr, and Hf; X is any one of Cl, Br, and I; The ether solvent is any one of diethyl ether, tetrahydrofuran, and ethylene glycol dimethyl ether; The L1 is ; L2 ; L3 is ; L4 is ; L5 is ; L6 is ; L7 is ; L8 is ; L9 is ; L10 is ; L11 is ; L12 is ; L13 is ; L14 is ; L15 is ; L16 is ; L17 is ; L18 is ; L19 is ; L20 is ; Where Ph is phenyl and Bu is n-butyl.

2. The method of synthesis of claim 1, wherein, R is a mono- or poly-substituent selected from the group consisting of H, C 1-6 alkyl, haloC 1-6 alkyl or C 1-6 alkoxy.

3. The method of synthesis of claim 1, wherein, R is a mono- or poly-substituent selected from H or C 1-6 alkyl.

4. The method of synthesis of claim 1, wherein, The substituted cyclopentadiene dimer is selected from n-butylcyclopentadiene dimer or 1-butyl-3-methyl-cyclopentadiene dimer.

5. The method of synthesis of claim 1, wherein, In step 1), the reaction continues until no more gas is generated.

6. The method of synthesis of claim 1, wherein, The reaction temperature in step 1) is 60-90℃.

7. The method of synthesis according to any one of claims 1-6, wherein, The reaction temperature in step 1) is 70-80℃.

8. The method of synthesis according to any one of claims 1-6, wherein, The reactants are used in the following amounts: 1.0 eq of cyclopentadiene dimer or substituted cyclopentadiene dimer, 2.0-4.0 eq of sodium or potassium, 0.05-0.2 eq of ionic liquid, and ether solvents are used to make the concentration of dimer in the system 0.5M-2M, and 1.0 eq of MX4.

9. The method of synthesis according to any one of claims 1-6, wherein, The reaction temperature in step 2) is -10 to 10℃.

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