阅读说明：本技术 一种含氮芳氧基茂钛化合物及其制备方法和应用 (Nitrogen-containing aryloxy cyclopentadienyl titanium compound and preparation method and application thereof ) 是由 王原 郭建双 郑浩 王新威 李济祥 徐绍魁 赵志成 于 2020-07-30 设计创作，主要内容包括：本发明涉及一种含氮芳氧基茂钛化合物及其制备方法和应用,制备方法为：含氮酚类配体化合物与三氯化茂钛化合物在有机溶剂中反应,后经过滤、浓缩、重结晶,即得到含氮芳氧基茂钛化合物,该含氮芳氧基茂钛化合物是一种高效的烯烃聚合催化剂,可用于乙烯或α-烯烃均聚、乙烯与α-烯烃共聚、烯烃与极性单体共聚等聚合反应。与现有技术相比,本发明的含氮芳氧基茂钛化合物的优点十分明显：原料易得,合成路线简单,产品收率高,性质比较稳定,同时具有较高的催化活性,能获得超高分子量的聚乙烯、聚丙烯、高共聚单体含量的乙烯与α-烯烃共聚物、烯烃与极性单体共聚物,能够满足工业应用的要求。(The invention relates to a nitrogen-containing aryloxy cyclopentadienyl titanium compound, a preparation method and application thereof, wherein the preparation method comprises the following steps: the nitrogen-containing phenolic ligand compound and the titanium trichloride compound react in an organic solvent, and then the nitrogen-containing aryloxy titanocene compound is obtained through filtration, concentration and recrystallization, and the nitrogen-containing aryloxy titanocene compound is a high-efficiency olefin polymerization catalyst and can be used for polymerization reactions such as ethylene or alpha-olefin homopolymerization, ethylene and alpha-olefin copolymerization, olefin and polar monomer copolymerization and the like. Compared with the prior art, the nitrogen-containing aryloxy titanocene compound has the advantages that: the method has the advantages of easily obtained raw materials, simple synthesis route, high product yield, relatively stable property and higher catalytic activity, can obtain polyethylene with ultrahigh molecular weight, polypropylene, ethylene and alpha-olefin copolymer with high comonomer content and olefin and polar monomer copolymer, and can meet the requirements of industrial application.)

1. The nitrogen-containing aryloxy titanocene compound is characterized by having the following chemical structural formula:

in the formula (I), the compound is shown in the specification,

R¹～R⁴each independently selected from one of the following groups: hydrogen, C₁～C₁₀Alkyl of linear, branched or cyclic structure, C₇～C₂₀Mono-or poly-aryl substituted alkyl, phenyl, halogen;

R⁵～R¹³each independently selected from one of the following groups: hydrogen, C₁～C₁₀Alkyl of linear, branched or cyclic structure, phenyl;

R¹⁴one selected from the following groups: a cyclopentadienyl group, a cyclopentadienyl group and a cyclopentadienyl group,indenyl, fluorenyl, C₁～C₁₅Monoalkyl-or polyalkyl-substituted cyclopentadienyl, C₁～C₁₅Monoalkyl-or polyalkyl-substituted indenyl, C₁～C₁₅Monoalkyl-or polyalkyl-substituted fluorenyl.

2. The nitrogen-containing aryloxycarbonyl titanocene compound of claim 1, wherein in formula (I),

R¹～R⁴each independently selected from one of the following groups: hydrogen, C₁～C₆Alkyl of linear, branched or cyclic structure, cumyl, phenyl, halogen;

R⁵～R¹³each independently selected from one of the following groups: hydrogen, C₁～C₆Alkyl of linear, branched or cyclic structure, phenyl;

R¹⁴one selected from the following groups: cyclopentadienyl, indenyl, fluorenyl, C₁～C₁₅Monoalkyl-or polyalkyl-substituted cyclopentadienyl, C₁～C₁₅Monoalkyl-or polyalkyl-substituted indenyl, C₁～C₁₅Monoalkyl-or polyalkyl-substituted fluorenyl.

3. A method for producing the nitrogen-containing aryloxycarbonyl titanium compound as claimed in claim 1 or 2, wherein the method comprises: reacting a nitrogen-containing phenol ligand compound with a titanocene trichloride compound in an organic solvent, and then filtering, concentrating and recrystallizing to obtain the nitrogen-containing aryloxy titanocene compound;

the chemical structural formula of the nitrogen-containing phenolic ligand compound is as follows:

the titanocene trichloride compound is R¹⁴TiCl₃。

4. The method of claim 3, wherein the organic solvent comprises one or two of tetrahydrofuran, diethyl ether, toluene, benzene, chloroform, dichloromethane, petroleum ether, and n-hexane.

5. The method for preparing the nitrogen-containing aryloxy titanocene compound according to claim 3, wherein the molar ratio of the nitrogen-containing phenolic ligand compound to the titanocene trichloride compound is 1 (1.0-2.0), the reaction temperature is-78-110 ℃, and the reaction time is 1-96 hours.

6. The method for preparing a nitrogen-containing aryloxycarbonyl titanocene compound as claimed in claim 5, wherein the reaction temperature is 0-70 ℃ and the reaction time is 1-24 h.

7. The use of a nitrogen-containing aryloxycarbonyl titanium compound as claimed in claim 1 or 2, wherein the nitrogen-containing aryloxycarbonyl titanium compound is used as a catalyst in olefin polymerization or copolymerization of an olefin and a polar monomer.

8. The use of a nitrogen-containing aryloxycarbonyl titanocene compound as in claim 7, wherein a cocatalyst and/or a support is further added during the use, and the homopolymerization or copolymerization is carried out by solution polymerization, emulsion polymerization, gas phase polymerization or slurry polymerization.

9. The use of a nitrogen-containing aryloxycarbonyl titanocene compound as claimed in claim 8, wherein the cocatalyst is alkylaluminoxane or borofluoride compound, the alkylaluminoxane is selected from methylaluminoxane, modified methylaluminoxane, ethylaluminoxane or isopropylaluminoxane, and the borofluoride compound is selected from bis (pentafluorophenyl) borane, tris (pentafluorophenyl) borane or tetrakis (pentafluorophenyl) boron salt;

the carrier is selected from one or two of porous silica gel, magnesium chloride, alumina, molecular sieve or clay;

the olefin is selected from ethylene, propylene, 1-hexene or 1-octene;

the polar monomer is an olefin derivative containing a polar group, and the polar group is selected from carbonyl, hydroxyl, carboxyl, ester group, alkoxy, amino, amido or thioether group.

10. The use of a nitrogen-containing aryloxycarbonyl titanocene compound as claimed in claim 9,

when olefin monomers are homopolymerized, a nitrogen-containing aryloxy cyclopentadienyl titanium compound is used as a main catalyst, alkyl aluminoxane or a boron fluorine compound is used as an auxiliary catalyst, the olefin monomers are homopolymerized at 0-150 ℃, and the molar ratio of the main catalyst to the auxiliary catalyst is 1 (1-100000);

when olefin monomers are copolymerized, a nitrogen-containing aryloxy cyclopentadienyl titanium compound is used as a main catalyst, alkyl aluminoxane or a boron fluorine compound is used as an auxiliary catalyst, at least two olefin monomers are copolymerized at 0-150 ℃, the molar ratio of the main catalyst to the auxiliary catalyst is 1 (1-100000), the pressure of the olefin monomers is 0.1-10.0 MPa, and the molar ratio of the catalyst to the olefin monomers is 1 (1000-100000);

when olefin and polar monomer are copolymerized, a nitrogen-containing aryloxy cyclopentadienyl titanium compound is used as a main catalyst, alkyl aluminoxane or boron fluorine compound is used as an auxiliary catalyst, the olefin monomer and the polar monomer are copolymerized at 0-150 ℃, the molar ratio of the main catalyst to the auxiliary catalyst is 1 (1-100000), the pressure of the olefin monomer is 0.1-10.0 MPa, the molar ratio of the polar monomer to the olefin monomer is 1 (1-1000), and the molar ratio of the catalyst to the olefin monomer is 1 (1000-100000).

Technical Field

The invention belongs to the technical field of olefin polymerization, and relates to a nitrogen-containing aryloxy ligand cyclopentadienyl titanium compound, a preparation method thereof and application thereof in olefin polymerization.

Background

Polyolefin materials such as Polyethylene (PE) and polypropylene (PP) have the advantages of high strength, low density, strong chemical corrosion resistance, low manufacturing cost and the like, and can replace common materials such as paper, wood, glass, metal, concrete and the like to a certain extent, so that the polyolefin materials have wide application and become the most widely applied polymer materials in the world today. Depending on the polymerization process, the molecular weight and the polymer chain differences, there are classifications of High Density Polyethylene (HDPE), Low Density Polyethylene (LDPE), Linear Low Density Polyethylene (LLDPE), isotactic polypropylene (iPP), syndiotactic polypropylene (sPP) and some high end polyolefin products. Essentially, the critical properties and the field of application of a polymer are determined mainly by its molecular structure, such as: molecular weight and its distribution, branching degree and short-chain branch distribution, crystallization and entanglement behavior of molecular chains, and the like, and the fundamental factor controlling the molecular chain structure is the catalyst. Therefore, designing and synthesizing a metal complex catalyst with a novel structure, and realizing the controllability of the olefin polymerization process and the polymer microstructure become the research core in the field.

Since the 90 s of the last century, scientists have been striving to find catalysts with superior catalytic performance and have made a series of important advances. Fujita et al, Mitsui, Japan, developed phenoxyimine titanium group metal complexes and found that they are useful for olefin polymerization. The ligand structure of the catalyst is easy to modify, the performance of the catalyst can be regulated and controlled by designing the framework structure of the catalyst, polyethylene and stereoregular polypropylene with different molecular weights are prepared, and the catalyst can also catalyze the copolymerization of ethylene and alpha-olefin, so that novel polyolefin materials (Catalysis today, 2011,164,2-8) with various varieties are developed. Researches show that the phenoxyl imine titanium compound has medium polymerization activity of catalyzing ethylene, the obtained polymer has narrow molecular weight distribution and active polymerization characteristic, and in addition, the catalyst can also effectively carry out propylene three-dimensional control polymerization. The phenoxyimine zirconium compound has extremely high polymerization activity for catalyzing ethylene, can prepare ultra-high molecular polyethylene, but has sensitive stability to temperature, can generate ligand dissociation at high temperature, and can inactivate the catalyst. The Brookhart group reports a nickel neutral salicylaldimine complex, which can realize the regulation and control of catalyst performance and polymer molecular weight by introducing different types of substituents on a ligand framework, introducing a steric hindrance anthracene group, a naphthyl group and other rigid groups on an aryloxy ring and imine respectively, and adjusting the space environment and electronic factors around a metal center, wherein the polymerization process can be carried out in a polar medium, but the catalyst preparation route is long and the synthesis cost is high (Journal of American Chemical Society,2018,140,6685 and 6689). The Sun group reports that quinoline imine ligand cyclopentadienyl titanium complex has high catalytic ethylene polymerization activity under the activation of Methylaluminoxane (MAO), and the ultrahigh molecular weight polyethylene with narrow molecular weight distribution is prepared; it also utilizes such titanium complexes to catalyze the copolymerization of ethylene and alpha-olefins to yield copolymers of ethylene and 1-hexene and ethylene and 1-octene with a certain short chain branch content (Journal of organometallic chemistry,2014,753, 34-41).

In summary, the research on olefin polymerization catalysts has made a major breakthrough, and the regulation and control of the catalyst activity, stability and polymer microstructure are achieved to some extent by the effective metal complex catalyst structure design. However, the metal complex catalyst reported at present is difficult to combine excellent catalytic activity and thermal stability, and the comonomer responsiveness is generally low. Therefore, there is a need to improve the framework structure of the metal complex, optimize the steric environment around the metal center and the electron density, and obtain a metal complex catalyst with stable catalytic performance and high comonomer responsiveness at high temperature.

Disclosure of Invention

One of the objects of the present invention is to provide a nitrogen-containing aryloxycarbonyl titanium compound.

The second purpose of the invention is to provide a preparation method of the nitrogen-containing aryloxy titanocene compound.

The invention also aims to provide an application of the nitrogen-containing aryloxy titanocene compound, which can be used as a catalyst to catalyze the polymerization of alpha-olefins such as ethylene, propylene and the like to obtain homopolymers of the alpha-olefins such as ethylene, propylene and the like; or catalyzing ethylene to be copolymerized with propylene, 1-hexene or 1-octene to obtain a copolymer of ethylene and propylene, 1-hexene or 1-octene; or catalyzing the olefin to be copolymerized with the polar monomer to obtain the copolymer of the olefin and the polar monomer.

The purpose of the invention can be realized by the following technical scheme:

a nitrogen-containing aryloxy titanocene compound has the following chemical structural formula:

in the formula (I), the compound is shown in the specification,

R¹～R⁴each independently selected from one of the following groups: hydrogen, C₁～C₁₀Alkyl of linear, branched or cyclic structure, C₇～C₂₀Mono-or poly-aryl substituted alkyl, phenyl, halogen;

R⁵～R¹³are independently selected respectivelyOne from the following groups: hydrogen, C₁～C₁₀Alkyl of linear, branched or cyclic structure, phenyl;

R¹⁴one selected from the following groups: cyclopentadienyl, indenyl, fluorenyl, C₁～C₁₅Monoalkyl-or polyalkyl-substituted cyclopentadienyl, C₁～C₁₅Monoalkyl-or polyalkyl-substituted indenyl, C₁～C₁₅Monoalkyl-or polyalkyl-substituted fluorenyl.

Preferably, in the formula (I),

R¹～R⁴each independently selected from one of the following groups: hydrogen, C₁～C₆Alkyl of linear, branched or cyclic structure, cumyl, phenyl, halogen;

R⁵～R¹³each independently selected from one of the following groups: hydrogen, C₁～C₆Alkyl of linear, branched or cyclic structure, phenyl;

R¹⁴one selected from the following groups: cyclopentadienyl, indenyl, fluorenyl, C₁～C₁₅Monoalkyl-or polyalkyl-substituted cyclopentadienyl, C₁～C₁₅Monoalkyl-or polyalkyl-substituted indenyl, C₁～C₁₅Monoalkyl-or polyalkyl-substituted fluorenyl.

The structural formula of a typical nitrogen-containing aryloxycarbonyl titanium compound is as follows:

a preparation method of nitrogen-containing aryloxy titanocene compound comprises the following steps: reacting a nitrogen-containing phenol ligand compound with a titanocene trichloride compound in an organic solvent, and then filtering, concentrating and recrystallizing to obtain the nitrogen-containing aryloxy titanocene compound;

the chemical structural formula of the nitrogen-containing phenolic ligand compound is as follows:

the titanocene trichloride compound is R¹⁴TiCl₃Preferably pentamethylcyclopentadienyltitanium trichloride or indenyl titanium trichloride.

The reaction formula is shown as follows:

in the nitrogen-containing phenol ligand compound and titanocene trichloride compound represented by the above reaction formula (II), the substituent R¹～R¹⁴Is consistent with the requirement of meeting all corresponding groups of the nitrogen-containing aryloxy titanocene compound.

Preferably, the organic solvent comprises one or two of tetrahydrofuran, diethyl ether, toluene, benzene, chloroform, dichloromethane, petroleum ether or n-hexane.

Preferably, the molar ratio of the nitrogen-containing phenol ligand compound to the titanocene trichloride compound is 1 (1.0-2.0), the reaction temperature is-78-110 ℃, and the reaction time is 1-96 h.

Preferably, the reaction temperature is 0-70 ℃, and the reaction time is 1-24 h.

The application of the nitrogen-containing aryloxy titanocene compound is used as a catalyst for olefin polymerization reaction or copolymerization reaction of olefin and polar monomer.

Preferably, when used, the catalyst promoter and/or the carrier are also added, and the homopolymerization or copolymerization is carried out by adopting a solution polymerization mode, an emulsion polymerization mode, a gas phase polymerization mode or a slurry polymerization mode.

Preferably, the cocatalyst is alkylaluminoxane selected from methylaluminoxane, modified methylaluminoxane, ethylaluminoxane or isopropylaluminoxane or a borofluoride compound selected from bis (pentafluorophenyl) borane, tris (pentafluorophenyl) borane or a tetrakis (pentafluorophenyl) boron salt;

the carrier is selected from one or two of porous silica gel, magnesium chloride, alumina, molecular sieve or clay;

the olefin is selected from alpha-olefin such as ethylene, propylene, 1-hexene or 1-octene;

the polar monomer is an olefin derivative containing a polar group, and the polar group is selected from carbonyl, hydroxyl, carboxyl, ester group, alkoxy, amino, amido or thioether group.

Preferably, when an olefin monomer is homopolymerized, the nitrogen-containing aryloxy titanocene compound is used as a main catalyst, alkyl aluminoxane or boron fluorine compound is used as a cocatalyst, so that the olefin monomer is homopolymerized at 0-150 ℃, and the molar ratio of the main catalyst to the cocatalyst is 1 (1-100000);

when olefin monomers are copolymerized, a nitrogen-containing aryloxy cyclopentadienyl titanium compound is used as a main catalyst, alkyl aluminoxane or a boron fluorine compound is used as an auxiliary catalyst, at least two olefin monomers are copolymerized at 0-150 ℃, the molar ratio of the main catalyst to the auxiliary catalyst is 1 (1-100000), the pressure of the olefin monomers is 0.1-10.0 MPa, and the molar ratio of the catalyst to the olefin monomers is 1 (1000-100000);

when olefin and polar monomer are copolymerized, a nitrogen-containing aryloxy cyclopentadienyl titanium compound is used as a main catalyst, alkyl aluminoxane or boron fluorine compound is used as an auxiliary catalyst, the olefin monomer and the polar monomer are copolymerized at 0-150 ℃, the molar ratio of the main catalyst to the auxiliary catalyst is 1 (1-100000), the pressure of the olefin monomer is 0.1-10.0 MPa, the molar ratio of the polar monomer to the olefin monomer is 1 (1-1000), and the molar ratio of the catalyst to the olefin monomer is 1 (1000-100000).

The technical conception of the invention is as follows:

the research finds that the complex with large steric hindrance substituent on the ligand not only shows high catalytic activity, but also can obtain polymers with higher regularity, therefore, the increase of the steric hindrance of the metal center is beneficial to protecting the active center, and can improve the stereo and regioselectivity of the polymerization process⁶The coordination mode greatly improves the stability of the complex. The quinoline imine ligand titanocene compound catalyzes ethylene polymerization to show moderate activity, and possible reasons are analyzedThe method comprises the following steps: 1) the cyclopentadienyl electron-donating effect of the cyclopentadienyl ligand part is weak, and the electron density around the metal center cannot be effectively adjusted; 2) the quinoline imine ligand has larger steric hindrance and stronger structural rigidity, and the coordination atoms are close to each other in space, so that the space around the active center of the catalyst is crowded, and the two factors are not beneficial to the coordination insertion of the monomer. Therefore, the invention considers the regulation of the ligand framework, and changes the coordination environment and the charge density around the metal center by introducing the phenol-pyridine-aromatic imine ligand with dispersed coordination atoms and the cyclopentadiene structural group with strong electron supply characteristic so as to realize the synthesis of the catalyst with high activity, thermal stability and high comonomer responsiveness.

Compared with the prior art, the nitrogen-containing aryloxy titanocene compound can be used as a high-efficiency olefin polymerization catalyst for polymerization reactions such as ethylene or alpha-olefin homopolymerization, ethylene and alpha-olefin copolymerization, olefin and polar monomer copolymerization and the like. The nitrogen-containing aryloxy titanocene compound has the following obvious advantages: the catalyst has the advantages of easily obtained raw materials, simple synthetic route, convenient preparation, high product yield, relatively stable property and higher catalytic activity, can obtain polyethylene and polypropylene with ultrahigh molecular weight and narrow molecular weight distribution, can obtain ethylene and alpha-olefin copolymer with high comonomer content and olefin and polar monomer copolymer, and can meet the requirements of industrial application.

Detailed Description

The present invention will be described in detail with reference to specific examples. The present embodiment is implemented on the premise of the technical solution of the present invention, and a detailed implementation manner and a specific operation process are given, but the scope of the present invention is not limited to the following embodiments.