阅读说明：本技术 一种金属配合物、其制备方法和应用 (Metal complex, preparation method and application thereof ) 是由 李彪 刘龙飞 赵永臣 刘振学 任学斌 栾波 于 2020-06-18 设计创作，主要内容包括：本发明提供了一种式(I)结构的金属配合物,本发明提供的上述新型[NOON]四齿第四副族金属配合物热稳定性好、催化活性高,其作为主催化剂催化烯烃聚合反应,在少量助催化剂的活化作用下,就可以高效的催化乙烯均聚,乙烯与降冰片烯、1-己烯以及1-辛烯的共聚反应。在高温条件下可以保持很好的催化活性；本发明提供的配合物催化乙烯均聚得到的聚乙烯的分子量最高达197.2×10<Sup>4</Sup>g/mol；催化乙烯和降冰片烯共聚得到的聚合物的分子量最高达34.7×10<Sup>4</Sup>g/mol,NBE插入率最高为44.8％；乙烯和1-己烯共聚得到的聚合物的分子量最高达45.4×10<Sup>4</Sup>g/mol,1-己烯插入率最高为16.1％。(The invention provides a metal complex with a structure of formula (I), and the novel [ NOON ] provided by the invention]The quadridentate fourth subgroup metal complex has good thermal stability and high catalytic activity, can be used as a main catalyst to catalyze olefin polymerization reaction, and can efficiently catalyze ethylene homopolymerization and the polymerization of ethylene, norbornene, 1-hexene and 1-octene under the activation of a small amount of cocatalystThe copolymerization reaction can keep good catalytic activity under the high temperature condition, and the molecular weight of the polyethylene obtained by homopolymerization of ethylene catalyzed by the complex provided by the invention can reach as high as 197.2 × 10 4 g/mol, the molecular weight of the polymer obtained by catalyzing the copolymerization of ethylene and norbornene is up to 34.7 × 10 4 g/mol, NBE insertion rate up to 44.8%, molecular weight of polymer obtained by copolymerization of ethylene and 1-hexene up to 45.4 × 10 4 g/mol, the highest insertion rate of 1-hexene is 16.1%.)

1. A metal complex with a structure of formula (I),

wherein R is₁Is C1-C10 alkyl, C6-C25 aryl or carbazolyl; r₂、R₃Independently selected from HAnd C1-C10 alkyl, n is an integer of 2-5, and X is halogen, alkyl, benzyl, amino or silyl; m is a fourth subgroup transition metal.

2. The complex of claim 1, wherein R is₁Is methyl, ethyl, isopropyl, n-butyl, isobutyl, tert-butyl, phenyl, 3, 5-di-tert-butylphenyl and carbazolyl; r₂And R₃Independently selected from hydrogen, methyl, ethyl, propyl, isopropyl, n-butyl or tert-butyl; x is halogen, methyl and benzyl; m is titanium, zirconium or hafnium.

3. The complex of claim 2, wherein R is₁Is methyl, isopropyl, n-butyl, 3, 5-di-tert-butylphenyl and carbazolyl; r₂And R₃Independently selected from hydrogen, methyl or tert-butyl; n is 3 or 4; m is Zr or Hf.

4. The complex as claimed in claim 1, wherein the metal complex of formula (I) is represented by formulae (I-1) to (I-16):

5. a method for preparing a metal complex having a structure of formula (I), comprising:

reacting a compound with a structure shown in a formula (II) with a compound with a structure shown in a formula (III) to obtain a ligand with a structure shown in a formula (IV);

dissolving the ligand with the structure of formula (IV) in a solvent, mixing with alkyl lithium, reacting, and then reacting with MX₄The suspension is reacted, the solvent is removed in vacuum, and the metal complex with the structure of the formula (I) is obtained after recrystallization;

wherein R is₁Is C1-C10 alkyl, C6-C25 aryl or carbazolyl; r₂、R₃Independently selected from alkyl groups of H, C1-C10, n is an integer of 2-5, and X is halogen, alkyl, benzyl, amino or silyl; m is a fourth subgroup transition metal.

6. Use of a metal complex of formula (I) as defined in any one of claims 1 to 4 as an olefin polymerisation catalyst.

7. Use according to claim 6, the olefin polymerization comprising homopolymerization of ethylene, copolymerization of ethylene with norbornene or copolymerization of ethylene with α -olefin.

8. A method for producing a polyolefin, comprising:

the metal complex with the structure of formula (I) as claimed in any one of claims 1 to 4 as a main catalyst, under the action of a cocatalyst, catalyzing olefin polymerization;

the olefin polymerization includes homopolymerization of ethylene, copolymerization of ethylene and norbornene, or copolymerization of ethylene and alpha-olefin.

9. The preparation method of claim 8, wherein the cocatalyst is one or more of alkylaluminoxane, modified alkylaluminoxane, halogenated alkylaluminium, alkylaluminium and boron agent.

10. The preparation method according to claim 9, wherein the molar ratio of the aluminum in the cocatalyst to the metal in the main catalyst is 5-1000: 1, the molar ratio of boron in the cocatalyst to metal in the main catalyst is 0-2: 1, and the pressure of ethylene during polymerization is 0.1-10 MPa.

Technical Field

The invention relates to the technical field of olefin polymerization catalysts, and particularly relates to a metal complex, and a preparation method and application thereof.

Background

The polyolefin product has the advantages of rich raw materials, low price, easy production and processing, good mechanical property, excellent performance and the like, so that the polyolefin product is a synthetic resin material which is most widely applied in production and life at present, and the development level of the polyolefin industry directly represents the development level of the national petrochemical industry and is an important component in national economy and national defense strategies.

The olefin polymerization catalyst directly determines the internal structure and the appearance of a polyolefin product, is the most core technology in the development process of the polyolefin industry, and the development of the polyolefin product mainly comprises three stages: a) Ziegler-Natta catalysts, which are the earliest polyolefin catalysts, have promoted and developed the polyolefin industry, but the structures of the catalysts are not easy to modify, the types are relatively single, the catalysts are heterogeneous during use, the catalysts are difficult to be completely activated by a cocatalyst, multiple active centers exist, the catalytic efficiency is low, the ash content in the obtained products is high, and the difficulty and the cost of post-treatment are increased; in addition, the catalyst can not catalyze the copolymerization of ethylene, norbornene and alpha-olefin, and the obtained product has single type and is difficult to meet the requirement of product diversification in practice. b) The appearance of this kind of catalyst basically solves the shortcomings of Ziegler-Natta catalyst, and greatly enriches the kinds of polyolefin products, but it needs to use a large amount of expensive co-catalyst (MAO or boron assistant) during the use, and the cost is high, the ash content in the obtained product is high, the active center is easy to be poisoned and deactivated, and the application in industrial production is limited. c) The non-metallocene catalyst has a single active center, relatively high activity and strong tolerance of central metal to heteroatoms, has the advantages of the first two generations of catalysts, can catalyze homopolymerization and copolymerization of multiple series of olefin monomers, realizes accurate control on the molecular weight and the internal appearance of polyolefin products, enriches the types of the polyolefin products, and has very wide application prospect.

A series of Salen type metal complexes applied by Exxon-Mobil company (eg: WO2017058388A1) are disclosed, the Salen type catalysts can catalyze ethylene homopolymerization and copolymerization of ethylene and a plurality of alpha-olefins, the activity is high, the product quality is good, but the temperature resistance of the catalysts is generally poor, the activity is low under high-temperature polymerization conditions, and even the catalysts are directly inactivated; the series of patents (eg: US2004010103A1) of the bridged tetraoxy type metal complex applied by Symyx company and the series of patents (eg: US20120108770A1) of the bridged tetraoxy type metal complex applied by Dow company have very excellent catalytic performance and high temperature tolerance, which can be named as the classic work of non-metallocene catalysts, but the synthesis process of the catalyst is very complicated and the synthesis cost is very high, especially in the aspects of selective protection and deprotection of hydroxyl and coupling of the hydroxyl by using a large amount of noble metal catalysis.

Therefore, it is necessary to design a new catalyst having excellent catalytic performance and good high temperature resistance, while reducing the synthesis cost of the catalyst.

Disclosure of Invention

In view of the above, the technical problem to be solved by the present invention is to provide a metal complex, which has the characteristics of high catalytic activity, high catalytic efficiency and low cocatalyst usage when used for catalyzing olefin polymerization.

The invention provides a metal complex with a structure shown in a formula (I),

wherein R is₁Is C1-C10 alkyl, C6-C25Aryl or carbazolyl groups; r₂、R₃Independently selected from alkyl groups of H, C1-C10, n is an integer of 2-5, and X is halogen, alkyl, benzyl, amino or silyl; m is a fourth subgroup transition metal.

Preferably, said R is₁Is methyl, ethyl, isopropyl, n-butyl, isobutyl, tert-butyl, phenyl, 3, 5-di-tert-butylphenyl and carbazolyl; r₂And R₃Independently selected from hydrogen, methyl, ethyl, propyl, isopropyl, n-butyl or tert-butyl; x is halogen, methyl and benzyl; m is titanium, zirconium or hafnium.

Preferably, said R is₁Is methyl, isopropyl, n-butyl, 3, 5-di-tert-butylphenyl and carbazolyl; r₂And R₃Independently selected from hydrogen, methyl or tert-butyl; n is 3 or 4; m is Zr or Hf.

Preferably, the metal complex with the structure of formula (I) is specifically represented by formulas (I-1) to (I-16):

the invention provides a preparation method of a metal complex with a structure shown in a formula (I), which comprises the following steps:

reacting a compound with a structure shown in a formula (II) with a compound with a structure shown in a formula (III) to obtain a ligand with a structure shown in a formula (IV);

dissolving the ligand with the structure of formula (IV) in a solvent, mixing with alkyl lithium, reacting, and then reacting with MX₄The suspension is reacted, the solvent is removed in vacuum, and the metal complex with the structure of the formula (I) is obtained after recrystallization;

wherein R is₁Is C1-C10 alkyl, C6-C25 aryl or carbazolyl; r₂、R₃Independently selected from alkyl groups of H, C1-C10, n is an integer of 2-5, and X is halogen, alkyl, benzyl, amino or silyl; m is a fourth subgroup transition metal.

The invention provides application of the metal complex with the structure of the formula (I) in any one of the technical schemes as an olefin polymerization catalyst.

Preferably, the olefin polymerization comprises homopolymerization of ethylene, copolymerization of ethylene with norbornene or copolymerization of ethylene with alpha-olefin.

The invention provides a preparation method of polyolefin, which comprises the following steps:

the metal complex with the structure of the formula (I) in any one of the technical schemes is used as a main catalyst to catalyze olefin polymerization under the action of a cocatalyst;

the olefin polymerization includes homopolymerization of ethylene, copolymerization of ethylene and norbornene, or copolymerization of ethylene and alpha-olefin.

Preferably, the cocatalyst is one or more of alkylaluminoxane, modified alkylaluminoxane, halogenated alkylaluminium, alkylaluminium and boron agent.

Preferably, the molar ratio of the aluminum in the cocatalyst to the metal in the main catalyst is 5-1000: 1, the molar ratio of boron in the cocatalyst to metal in the main catalyst is 0-2: 1, and the pressure of ethylene during polymerization is 0.1-10 MPa.

Compared with the prior art, the invention provides a metal complex with a structure shown in formula (I), and the novel [ NOON ] provided by the invention]The quadridentate fourth subgroup metal complex has the advantages of good thermal stability, high catalytic activity and the like, can be used as a main catalyst to catalyze olefin polymerization, and can efficiently catalyze ethylene homopolymerization and copolymerization of ethylene, norbornene, 1-hexene and 1-octene under the activation of a small amount of cocatalyst. Can be well maintained under high temperatureThe experiment result shows that the highest molecular weight of the polyethylene obtained by homopolymerization of ethylene under the catalysis of the complex provided by the invention is 197.2 × 10⁴g/mol, the molecular weight of the polymer obtained by catalyzing the copolymerization of ethylene and norbornene is up to 34.7 × 10⁴g/mol, NBE insertion rate up to 44.8%, molecular weight of polymer obtained by copolymerization of ethylene and 1-hexene up to 45.4 × 10⁴g/mol, the highest insertion rate of 1-hexene is 16.1%, and the highest molecular weight of the polymer obtained by copolymerization of ethylene and 1-octene is 44.6 × 10⁴g/mol, the highest insertion rate of 1-octene is 12.1%.

Drawings

FIG. 1 is a nuclear magnetic resonance hydrogen spectrum of a complex C5 provided in example 2 of the present invention.

Detailed Description

The invention provides a metal complex, a preparation method and application thereof, and a person skilled in the art can appropriately improve process parameters by referring to the content. It is expressly intended that all such similar substitutes and modifications apparent to those skilled in the art are deemed to be within the scope of the invention. While the methods and applications of this invention have been described in terms of preferred embodiments, it will be apparent to those of ordinary skill in the art that variations and modifications in the methods and applications described herein, as well as other suitable variations and combinations, may be made to implement and use the techniques of this invention without departing from the spirit and scope of the invention.

The invention provides a metal complex with a structure shown in a formula (I),

wherein R is₁Is C1-C10 alkyl, C6-C25 aryl or carbazolyl; preferably methyl, ethyl, isopropyl, n-butyl, isobutyl, tert-butyl, phenyl, 3, 5-di-tert-butylphenyl, carbazolyl; more preferably methyl, isopropyl, n-butyl, 3, 5-di-tert-butylphenyl and carbazolyl;

R₂、R₃independently selected from alkyl of H, C1-C10, preferably independently selected from hydrogen, methyl and ethylPropyl, isopropyl, n-butyl or tert-butyl; more preferably independently selected from hydrogen, methyl or tert-butyl;

n is an integer of 2 to 5, and specifically may be 2, 3, 4 or 5.

X is halogen, alkyl, benzyl, amino or silyl; halogen, methyl and benzyl are preferred.

M is a fourth subgroup transition metal; preferably M is titanium, zirconium or hafnium; more preferably Zr or Hf.

In the invention, the metal complex with the structure of formula (I) is specifically represented by formulas (I-1) to (I-16):

the invention provides a preparation method of a metal complex with a structure shown in a formula (I), which comprises the following steps:

reacting a compound with a structure shown in a formula (II) with a compound with a structure shown in a formula (III) to obtain a ligand with a structure shown in a formula (IV);

dissolving the ligand with the structure of formula (IV) in a solvent, mixing with alkyl lithium, reacting, and then reacting with MX₄The suspension is reacted, the solvent is removed in vacuum, and the metal complex with the structure of the formula (I) is obtained after recrystallization;

wherein R is₁Is C1-C10 alkyl, C6-C25 aryl or carbazolyl; preferably methyl, ethyl, isopropyl, n-butyl, isobutyl, tert-butyl, phenyl, 3, 5-di-tert-butylphenyl, carbazolyl; more preferably methyl, isopropyl, n-butyl, 3, 5-di-tert-butylphenyl and carbazolyl;

R₂、R₃independently selected from alkyl groups H, C1-C10, preferably independently selected from hydrogen, methyl, ethyl, propyl, isopropyl, n-butyl or tert-butyl; more preferably independently selected from hydrogen, methyl or tert-butyl;

n is an integer of 2 to 5, and specifically may be 2, 3, 4 or 5.

X is halogen, alkyl, benzyl, amino or silyl; halogen, methyl and benzyl are preferred.

M is a fourth subgroup transition metal; preferably M is titanium, zirconium or hafnium; more preferably Zr or Hf.

The structure of the metal complex is convenient to modify; the catalyst has good temperature resistance, and can keep good catalytic activity under the high-temperature condition; the catalyst has high activity of catalyzing ethylene homopolymerization, and ultrahigh molecular weight polyethylene can be obtained; the catalyst catalyzes the copolymerization reaction of ethylene, norbornene, 1-hexene and 1-octene, and has high activity and high comonomer insertion rate in the polymer.

The invention provides a preparation method of a metal complex with a structure shown in a formula (I), which comprises the step of reacting a compound with a structure shown in a formula (II) with a compound with a structure shown in a formula (III) to obtain a ligand with a structure shown in a formula (IV).

Namely:

wherein, the preparation process of the compound with the structure of the formula (II) is as follows:

dissolving the ligand with the structure of formula (IV) in a solvent, mixing with alkyl lithium, reacting, and then reacting with MX₄The suspension is reacted, the solvent is removed in vacuum, and the metal complex with the structure of the formula (I) is obtained after recrystallization.

The ligand is dissolved in a solvent under an inert gas atmosphere, including but not limited to toluene; and then cooled to 0 ℃. The inert gas is preferably nitrogen.

And then mixed with an alkyllithium, preferably methyllithium or n-butyllithium. Preferably, alkyl lithium is dripped, and then the reaction is carried out at room temperature for 2-3 h.

Then with MX₄The suspension of (3) is reacted. The preferable concrete is as follows:

it was slowly transferred with a double-ended needle to MX, which had been cooled to-40 ℃ beforehand₄Keeping the suspension of (M ═ Zr or Hf, X ═ Cl) in toluene, reacting for 0.5-1 h at low temperature, slowly raising the temperature to room temperature, and continuing the reaction for 10-12 h, wherein the solution is transparent.

Then removing the solvent in vacuum, and recrystallizing to obtain the metal complex with the structure of the formula (I).

The preferable concrete is as follows: vacuum extracting volatile components from the reaction solution, adding dry diethyl ether, filtering to remove inorganic salts, vacuum extracting diethyl ether, and adding toluene/n-hexane or CH₂Cl₂And recrystallizing the product by n-hexane to obtain the metal complex.

The invention provides application of the metal complex with the structure of the formula (I) in any one of the technical schemes as an olefin polymerization catalyst.

The olefin polymerization of the invention comprises ethylene homopolymerization, ethylene and norbornene copolymerization or ethylene and alpha-olefin copolymerization.

The catalyst of the invention catalyzes the copolymerization reaction of ethylene, norbornene, 1-hexene and 1-octene, the activity is very high and the monomer insertion rate in the polymer is also very high.

The invention provides a preparation method of polyolefin, which comprises the following steps:

the metal complex with the structure of the formula (I) in any one of the technical schemes is used as a main catalyst to catalyze olefin polymerization under the action of a cocatalyst;

the olefin polymerization includes homopolymerization of ethylene, copolymerization of ethylene and norbornene, or copolymerization of ethylene and alpha-olefin.

The preparation method of polyolefin provided by the invention takes the metal complex with the structure of formula (I) as a main catalyst, and olefin polymerization is catalyzed under the action of a cocatalyst.

The olefin polymerization of the invention comprises ethylene homopolymerization, ethylene and norbornene copolymerization or ethylene and alpha-olefin copolymerization. The cocatalyst is one or more of alkyl aluminoxane, modified alkyl aluminoxane, halogenated alkyl aluminum, alkyl aluminum and a boron agent. That is specifically: alkyl aluminoxane, modified alkyl aluminoxane, halogenated alkyl aluminum or a mixture of alkyl aluminum and a boron agent is used as a cocatalyst.

According to the invention, the molar ratio of aluminum in the cocatalyst to metal in the main catalyst is preferably 5-1000: 1; more preferably 50 to 500: 1,

the molar ratio of boron in the cocatalyst to metal in the main catalyst is 0-2: 1, and the pressure of ethylene during polymerization is preferably 0.1-10 MPa; more preferably 0.1 to 4 MPa.

The temperature and time of the polymerization reaction are not limited in the present invention and are well known to those skilled in the art.

The invention provides a metal complex with a structure of formula (I), and the novel [ NOON ] provided by the invention]The quadridentate fourth subgroup metal complex has the advantages of good thermal stability, high catalytic activity and the like, can be used as a main catalyst to catalyze olefin polymerization reaction, can efficiently catalyze homopolymerization of ethylene and copolymerization of ethylene, norbornene, 1-hexene and 1-octene under the activation action of a small amount of cocatalyst, and can maintain good catalytic activity under high temperature condition, and experimental results show that the molecular weight of polyethylene obtained by homopolymerization of ethylene catalyzed by the complex provided by the invention can reach as high as 197.2 × 10⁴g/mol; catalysis BThe molecular weight of the polymer obtained by copolymerizing the alkene and the norbornene can reach up to 34.7 × 10⁴g/mol, NBE insertion rate up to 44.8%, molecular weight of polymer obtained by copolymerization of ethylene and 1-hexene up to 45.4 × 10⁴g/mol, the highest insertion rate of 1-hexene is 16.1%, and the highest molecular weight of the polymer obtained by copolymerization of ethylene and 1-octene is 44.6 × 10⁴g/mol, the highest insertion rate of 1-octene is 12.1%.

In order to further illustrate the present invention, the following examples are provided to describe a metal complex, its preparation method and application in detail.