阅读说明：本技术 一种双核钒催化剂及其制备方法和应用 (Dual-core vanadium catalyst and preparation method and application thereof ) 是由 侯小华 陈小建 高翔 聂金鑫 周昕玥 邹辉 周丽 于 2020-07-20 设计创作，主要内容包括：本发明公开了一种双核钒催化剂,其结构通式如下：<Image he="364" wi="700" file="DDA0002591860100000011.GIF" imgContent="drawing" imgFormat="GIF" orientation="portrait" inline="no"></Image>其中,Linker的结构式为<Image he="116" wi="700" file="DDA0002591860100000012.GIF" imgContent="drawing" imgFormat="GIF" orientation="portrait" inline="no"></Image><Image he="117" wi="229" file="DDA0002591860100000013.GIF" imgContent="drawing" imgFormat="GIF" orientation="portrait" inline="no"></Image>中的一种；R<Sub>1</Sub>、R<Sub>2</Sub>、R<Sub>3</Sub>、R<Sub>4</Sub>、R<Sub>5</Sub>、R′<Sub>1</Sub>、R′<Sub>2</Sub>、R′<Sub>3</Sub>、R′<Sub>4</Sub>、R′<Sub>5</Sub>均为氢原子、烷基基团、氟原子、溴原子、氯原子中的一种或几种；上述双核钒催化剂包含吸电子基团能够用于催化反应能力弱的单体和其他环烯烃单体的开环易位聚合反应,能有效调节极性基团数量和控制聚合物的拓扑结构,为合成功能化聚烯烃提供新的策略。(The invention discloses a binuclear vanadium catalyst, which has the following structural general formula: wherein the structural formula of the Linker is One of (1); r 1 、R 2 、R 3 、R 4 、R 5 、R′ 1 、R′ 2 、R′ 3 、R′ 4 、R′ 5 Are one or more of hydrogen atom, alkyl group, fluorine atom, bromine atom and chlorine atom; the binuclear vanadium catalyst contains electron-withdrawing groups, can be used for ring-opening metathesis polymerization of monomers with weak catalytic reaction capability and other cycloolefin monomers, and can effectively adjust the number of polar groups and control polymersThe topological structure of (2) provides a new strategy for synthesizing the functionalized polyolefin.)

1. A binuclear vanadium catalyst is characterized by containing a bimetallic center and being bridged by covalent bonds, and the structural general formula of the binuclear vanadium catalyst is as follows:

wherein the structural formula of the Linker is

R₁、R₂、R₃、R₄、R₅、R′₁、R′₂、R′₃、R′₄、R′₅are each a hydrogen atom, an alkyl groupOne or more of fluorine atom, bromine atom and chlorine atom.

2. The method for preparing the binuclear vanadium catalyst according to claim 1, comprising the steps of:

(1) preparation of binuclear vanadium trichloride: weighing a reagent A in a Schlenk bottle under the protection of nitrogen, adding a solvent n-octane, slowly adding vanadium oxychloride, putting the Schlenk bottle in an oil bath, stirring at 120-140 ℃ for 6-12 h, filtering with diatomite to obtain a dark green solution, removing the solvent from the filtrate in vacuum, washing with n-hexane and DCM, standing at-5 ℃ for 6h, and removing the solvent in vacuum to obtain a dark green solid product a;

(2) preparation of binuclear vanadium trialkyl: weighing the product obtained in the step (1), putting the product into a reaction bottle, adding a solvent toluene, standing for 1h at minus 5 ℃, slowly adding a reagent B, stirring for 6h at room temperature, filtering by using diatomite to obtain a reddish brown solution, and removing the solvent in vacuum to obtain a reddish brown oily product B;

(3) preparation of binuclear vanadium dialkylate: weighing the product obtained in the step (2), putting the product into a reaction bottle, adding a solvent C, standing for 1h at minus 5 ℃, adding a reagent C in two batches, stirring for 12h at room temperature, filtering through diatomite to obtain a brown solution, and removing the solvent in vacuum to obtain the binuclear vanadium catalyst;

wherein the reagent A is one of 2, 6-dimethyl isocyanate, 2, 6-diisopropyl isocyanate and 2, 4-difluoro isocyanate;

the reagent B is 0.56M LiCH₂SiMe₃A hexane solution;

the reagent C is one of 4, 4-dihydroxy biphenyl, 3,5,3',5' -tetramethyl-4, 4 '-biphenyl diphenol, 4' -methylene bis (2, 6-xylenol) and biphenyl diphenol;

the solvent C is one or more of toluene, THF, n-hexane, n-octane and DCM.

3. Use of the binuclear vanadium catalyst according to claim 1, characterized in that: can be applied to catalyzing olefin polymerization.

4. The use of the dinuclear vanadium catalyst according to claim 3, characterized in that: the inclusion of electron withdrawing groups can be used to catalyze the ring-opening metathesis polymerization of monomers that are poorly reactive and other cyclic olefin monomers.

5. The use of the dinuclear vanadium catalyst according to claim 3, characterized in that: the specific application process is as follows:

under the protection of anhydrous and oxygen-free nitrogen, sequentially adding a monomer D and a solvent toluene into a screw-top bottle, and then adding a binuclear vanadium catalyst and PMe₃Stirring at 80 ℃, adding methanol to terminate the reaction after 1-4 h, washing the obtained product with methanol, and drying in vacuum until the quality is unchanged to obtain a ring-opening metathesis polymerization product;

wherein the monomer D is one or more of norbornene, cyclopentene, cyclooctene, norbornadiene and cyclooctadiene.

6. The use of the dinuclear vanadium catalyst according to claim 5, characterized in that:

when the added monomer D is norbornene, the binuclear vanadium catalyst is monomer D and PMe₃When the mass of the monomer norbornene is 200mg, PMe is at a molar ratio of 1:850:5₃When the mass of (2) is 1.9mg, the amount of the solvent toluene is 4 to 5 mL.

7. The use of the dinuclear vanadium catalyst according to claim 5, characterized in that:

when the added monomer D is cyclopentene, the binuclear vanadium catalyst is monomer D and PMe₃In a molar ratio of 1:5880:10, PMe when the mass of the monomer cyclopentene is 1.02mg₃When the mass of (B) is 1.9mg, the amount of the solvent toluene is 0.6-0.8 mL.

Technical Field

The invention belongs to the field of olefin polymerization organic metal catalysts and olefin coordination polymerization, and particularly relates to a binuclear vanadium catalyst and a preparation method and application thereof.

Background

Polyolefins are the largest polymer material produced commercially, accounting for about half of the world's thermoplastic yield. The material is widely applied to various fields of industrial production due to light weight, low price and low hygroscopicity, but due to the non-polarity and low surface energy, the dyeing property, the adhesive property, the hydrophilicity, the antistatic property and the compatibility with other polar high polymers or inorganic fillers are poor, so that the expansion of the application range is limited. Therefore, functionalization of nonpolar polyolefin, that is, introduction of polar functional groups or polymer segments into the molecular chain of the polyolefin can significantly improve the properties of the polymer material, such as flexibility, adhesion, barrier properties, surface properties, solvent resistance, miscibility with other polymers, rheology, etc., and becomes one of important research directions for expanding the application field of polyolefin materials.

In recent 20 years, the research on binuclear catalysts has been extensively carried out, and different metals are connected through the covalent bond action of complex ligands. Or the two metal centers are linked together by a dinuclear cocatalyst, thereby exhibiting a synergistic effect in catalyzing olefin polymerization.

A series of binuclear vanadium complexes with adjustable frameworks are designed and synthesized, the purpose of adjusting the distance between metal atoms is realized by adopting different frameworks, and the possibility is provided for researching the synergistic effect of different metal centers. Particularly, the screening of the substituent on the ligand can further realize the regulation of steric hindrance and electronic environment around the metal atom, thereby establishing a representative vanadium complex system with synergistic action and disclosing the internal relation between the spatial position of the metal atom of the complex and the synergistic action.

Disclosure of Invention

The invention aims to: firstly, reacting a trichloride of binuclear vanadium with an alkyl lithium reagent to obtain an alkylation product. And then reacting the obtained alkylation product with a bisphenol reagent according to a precise feeding ratio to obtain a binuclear vanadium dialkyl compound, and adding certain trimethylphosphine at room temperature to promote an alpha-H elimination reaction to generate an alkylidene complex of metal vanadium or vanadium carbene. The method can synthesize and separate a series of dialkylates of binuclear vanadium, and find that the dialkylates can efficiently initiate ring-opening metathesis polymerization of norbornene and cyclopentene at room temperature, and have higher catalytic activity and better performance on the aspect of controlling the microstructure of a polymer compared with a mononuclear vanadium complex.

In order to achieve the purpose, the invention provides the following technical scheme:

a binuclear vanadium catalyst has the following structural general formula:

wherein the structural formula of the Linker is

One of (1);

R₁、R₂、R₃、R₄、R₅、R′₁、R′₂、R′₃、R′₄、R′₅is one or more of hydrogen atom, alkyl group, fluorine atom, bromine atom and chlorine atom.

A preparation method of a binuclear vanadium catalyst comprises the following steps:

(1) preparation of binuclear vanadium trichloride: weighing a reagent A in a Schlenk bottle under the protection of nitrogen, adding a solvent n-octane, slowly adding vanadium oxychloride, putting the Schlenk bottle in an oil bath, stirring at 120-140 ℃ for 6-12 h, filtering with diatomite to obtain a dark green solution, removing the solvent from the filtrate in vacuum, washing with n-hexane and DCM, standing at-5 ℃ for 6h, and removing the solvent in vacuum to obtain a dark green solid product a;

(2) preparation of binuclear vanadium trialkyl: weighing the product obtained in the step (1), putting the product into a reaction bottle, adding a solvent toluene, standing for 1h at minus 5 ℃, slowly adding a reagent B, stirring for 6h at room temperature, filtering by using diatomite to obtain a reddish brown solution, and removing the solvent in vacuum to obtain a reddish brown oily product B;

(3) preparation of binuclear vanadium dialkylate: weighing the product obtained in the step (2), putting the product into a reaction bottle, adding a solvent C, standing for 1h at minus 5 ℃, adding a reagent C in two batches, stirring for 12h at room temperature, filtering through diatomite to obtain a brown solution, and removing the solvent in vacuum to obtain the binuclear vanadium catalyst;

wherein the reagent A is one of 2, 6-dimethyl isocyanate, 2, 6-diisopropyl isocyanate and 2, 4-difluoro isocyanate;

the reagent B is 0.56M LiCH₂SiMe₃A hexane solution;

the reagent C is one of 4, 4-dihydroxy biphenyl, 3,5,3',5' -tetramethyl-4, 4 '-biphenyl diphenol, 4,4' -methylene bis (2, 6-xylenol) and biphenyl diphenol;

the solvent C is one or more of toluene, THF, n-hexane, n-octane and DCM.

The application of a binuclear vanadium catalyst can be applied to catalyzing olefin polymerization.

Preferably, ROMP can be used for monomers comprising electron withdrawing groups and monomers comprising heteroatoms that are less reactive.

Preferably, the application of the binuclear vanadium catalyst comprises the following specific application processes:

under the protection of anhydrous oxygen-free nitrogen, sequentially adding a monomer D and a solvent toluene in a screw-top bottle, then adding a binuclear vanadium catalyst and trimethylphosphine, stirring at 80 ℃, adding methanol to terminate the reaction after 0.25-4 h, washing the obtained product with methanol, and drying in vacuum until the quality is unchanged to obtain a ring-opening metathesis polymerization product;

wherein the monomer D is one or more of norbornene, cyclopentene, cyclooctene, norbornadiene and cyclooctadiene.

Preferably, when addedWhen the monomer D is norbornene, the binuclear vanadium catalyst is the monomer D PMe₃When the mass of the monomer norbornene is 200mg, PMe is at a molar ratio of 1:850:5₃When the mass of (2) is 1.9mg, the amount of toluene as a solvent is 4 to 5mL, and the general formula of ring-opening metathesis polymerization is as follows:

preferably, when the added monomer D is cyclopentene, the binuclear vanadium catalyst is monomer D and PMe₃In a molar ratio of 1:5880:10, PMe when the mass of the monomer cyclopentene is 1.02mg₃When the mass of the catalyst is 1.9mg, the amount of the solvent toluene is 0.6-0.8 mL; the general formula of the ring-opening metathesis polymerization is as follows:

the invention relates to a binuclear vanadium catalyst, a preparation method and application thereof, wherein the general formula of the synthetic reaction is as follows:

the binuclear vanadium catalyst provided by the invention has the following beneficial effects:

(1) the binuclear vanadium catalyst disclosed by the invention is simple to synthesize, the catalyst structure can be reasonably adjusted, the preparation conditions are not harsh, the operation is simple, and the reaction is easy to carry out.

(2) The ring-opening metathesis polymerization carried out in the present invention can produce not only linear polymers but also cyclic polymers.

(3) The binuclear vanadium carbene complex is used for catalyzing the ring-opening metathesis polymerization reaction of cycloolefins for the first time, the synergistic effect among metals is researched, the recognition blank in the field is filled up, the application of the ring-opening metathesis polymerization method is enriched, and the binuclear vanadium carbene complex has strong original innovativeness; provides a new strategy for synthesizing cyclic polymers.

Drawings

FIG. 1 is a nuclear magnetic hydrogen spectrum of a product P1 obtained after ring-opening metathesis polymerization of norbornene in example 1 of the present invention, and it can be confirmed that the structure of the obtained polymer P1 corresponds to the general polymerization formula.

FIG. 2 is a nuclear magnetic hydrogen spectrum of a product P2 obtained by ring-opening metathesis polymerization of cyclopentene in example 2 of the present invention, and it can be confirmed that the structure of the obtained polymer P2 corresponds to the general polymerization formula.

FIG. 3(a) is a graph of molecular weight, molecular weight distribution and temperature for ring-opening metathesis polymerization of norbornene in example 1 of this invention, the molecular weight gradually decreases with increasing temperature, illustrating that temperature has a significant effect on catalyst activity; (b) is a graph of the relationship between the molecular weight and the molecular weight distribution of the ring-opening metathesis polymerization of norbornene and time in example 1 of the present invention, and shows that the molecular weight does not change significantly with the increase of time, which shows that the catalyst activity does not depend on the temperature.

FIG. 4 is a nuclear magnetic hydrogen spectrum diagram of Cat.1 having a framework structure of 4, 4-dihydroxybiphenyl according to example 1 of the present invention, and the molecular formula structure of the obtained catalyst can be determined.

FIG. 5 is a nuclear magnetic hydrogen spectrum diagram of Cat.2 of 3,5,3',5' -tetramethyl-4, 4' -biphenol as a framework structure in example 2 of the present invention, and the molecular formula structure of the obtained catalyst can be determined.

FIG. 6 is a nuclear magnetic hydrogen spectrum diagram of Cat.3 having a skeleton structure of 4,4' -methylenebis (2, 6-xylenol) in example 3 of the present invention, and the molecular formula structure of the obtained catalyst can be determined.

FIG. 7 is a nuclear magnetic hydrogen spectrum diagram of Cat.4 with a skeleton structure of biphenol in example 4 of the present invention, and the molecular formula structure of the obtained catalyst can be determined.

Detailed Description

The technical solutions in the embodiments of the present invention will be described clearly and completely below, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.