阅读说明：本技术 一种含二氮杂萘酮结构的ivb族金属配体的催化剂体系及其应用 (Catalyst system of IVB group metal ligand containing phthalazinone structure and application thereof ) 是由 郗朕捷 刘万弼 王金强 林小杰 郭华 张彦雨 于 2020-06-12 设计创作，主要内容包括：本发明提供了一种含二氮杂萘酮结构的IVB族金属配体的催化剂体系及其在乙烯/1-辛烯共聚合中的应用,催化剂体系由包含如式Ⅰ结构所示的含二氮杂萘酮结构的IVB族金属配体和助催化剂；其中,助催化剂为含铝元素的助催化剂,助催化剂中铝元素与所述含二氮杂萘酮结构的IVB族金属配体的摩尔比为(10～1000)：1；本发明还提供了上述催化剂体系的应用,在上述催化剂体系的存在下,乙烯与1-辛烯进行聚合反应后得到聚合物；含二氮杂萘酮结构的IVB族金属配体的催化剂体系的催化活性为8×10<Sup>7</Sup>～1.2×10<Sup>8</Sup>g/(mol·M·h)；聚合物的重均分子量为1×10<Sup>5</Sup>～2.5×10<Sup>5</Sup>g/mol,分子量分布为2.0～4.0；<Image he="259" wi="700" file="DDA0002536760140000011.GIF" imgContent="drawing" imgFormat="GIF" orientation="portrait" inline="no"></Image>(The invention provides a catalyst system of IVB group metal ligand containing phthalazinone structure and application thereof in ethylene/1-octene copolymerization, wherein the catalyst system comprises IVB group metal ligand containing phthalazinone structure shown as a formula I structure and a cocatalyst; the cocatalyst is an aluminum-containing cocatalyst, and the molar ratio of the aluminum element in the cocatalyst to the IVB group metal ligand containing the phthalazinone structure is (10-1000): 1; the invention also provides the application of the catalyst system, in the presence of the catalyst system, the ethylene and the 1-Octene polymerizing to obtain polymer, and catalyst system containing IVB group metal ligand with phthalazinone structure and having catalytic activity of 8 × 10 7 ～1.2×10 8 g/(mol. M.h), the weight average molecular weight of the polymer is 1 × 10 5 ～2.5×10 5 g/mol, the molecular weight distribution is 2.0-4.0;)

1. A catalyst system containing a diazanaphthalenone structure group IVB metal ligand is characterized in that the catalyst system consists of a group IVB metal ligand containing a diazanaphthalenone structure shown as a structure in a formula I and a cocatalyst;

the cocatalyst is an aluminum-containing cocatalyst, and the molar ratio of the aluminum element in the cocatalyst to the IV B group metal ligand containing the phthalazinone structure is (10-1000): 1, preferably (50-500): 1;

in formula I, M is selected from group IVB metals, preferably from titanium, zirconium or hafnium;

R₁～R₇each independently selected from hydrogen, halogen, alkyl, alkoxy, aryl, aralkyl, aryloxy, aralkoxy, silyl, imino.

2. The catalyst system of claim 1, wherein in the group IVB metal ligand containing a phthalazinone structure of formula I, R is₁～R₇Each independently selected from hydrogen, halogen, alkyl, alkoxy, aryl, aralkyl;

R₁～R₂preferably from halogen, alkyl, aralkyl;

R₃～R₇preferably from halogen, alkyl, aralkyl.

3. The catalyst system according to claim 1 or 2, characterized in that the cocatalyst is selected from alumoxanes and/or modified alumoxanes;

the aluminoxane is preferably selected from methylaluminoxane;

the modified aluminoxane is preferably selected from triisobutylaluminum-modified methylaluminoxane.

4. The catalyst system according to any one of claims 1 to 3, wherein the group IVB metal ligand containing a phthalazinone structure represented by the formula I is prepared by a method comprising the following steps:

1) dissolving a compound shown as a structure in a formula II in an organic solvent to obtain a reaction solution I, wherein the organic solvent is preferably tetrahydrofuran;

2) adding sodium hydride into the first reaction solution at-78-20 ℃ and reacting for 6-24 h;

3) continuously adding a compound shown in the following formula III structure into a reaction system at-78-20 ℃, and reacting for 6-24 h to obtain the IVB group metal ligand containing the phthalazinone structure;

preferably, filtering the product obtained by the reaction, washing and drying the obtained filter cake;

wherein R is₁～R₇Each independently selected from hydrogen, halogen, alkyl, alkoxy, aryl, aralkyl, aryloxy, aralkoxy, silyl, imino;

R₈～R₉each independently selected from halogen, alkyl, aryl, aralkyl.

5. The catalyst system of claim 4 wherein R is selected from the group consisting of compounds of formula II and compounds of formula III₁～R₂Selected from halogen, alkyl, aralkyl, R₃～R₇Selected from alkyl, aryl, aralkyl, R₈～R₉Selected from halogens.

6. The catalyst system of claim 5, wherein in step 2), sodium hydride is added to the first reaction solution under the protection of a nitrogen atmosphere;

preferably, the molar ratio of the sodium hydride to the compound shown in the formula II in the step 1) is (1-1.5): 1, and preferably 1: 1.

7. The catalyst system of claim 6, wherein in the step 3), the molar ratio of the compound represented by the structure in the formula III to the compound represented by the structure in the formula II in the step 1) is 1 (2-2.1), preferably 1: 2.

8. The application of a catalyst system containing IVB group metal ligand with a phthalazinone structure is characterized in that in the presence of the catalyst system as claimed in any one of claims 1 to 7, ethylene and 1-octene are subjected to polymerization reaction to obtain a polymer;

wherein the catalytic activity of the catalyst system containing the IVB group metal ligand with the phthalazinone structure is 8 × 10⁷～1.2×10⁸g/(mol·M·h)；

The weight average molecular weight of the polymer was 1 × 10⁵～2.5×10⁵g/mol, the molecular weight distribution is 2.0-4.0;

preferably, the catalytic activity of the catalyst system containing the IVB group metal ligand with the phthalazinone structure at 150-200 ℃ is 8 × 10⁷～1.2×10⁸g/(mol·M·h)。

9. The application of claim 8, wherein the IVB group metal ligand containing the phthalazinone structure shown in the formula I is dried, the cocatalyst and 1-octene are added, the temperature is raised to 100-200 ℃, and ethylene is added for the polymerization reaction;

wherein the pressure of the introduced ethylene is 1-5 MPa, preferably 2-4 MPa;

preferably, the polymerization reaction is carried out for 5-60 min at 0-250 ℃ and 1-5 MPa; more preferably, the polymerization reaction is carried out at 100-200 ℃ and 2-4 MPa for 10-40 min.

10. The application of the polymer as claimed in claim 8 or 9, wherein after the polymerization reaction is finished, the reaction solution of the polymerization reaction is neutralized by using 5-10% by mass of acid solution, a product is precipitated, and then the product is washed and dried to obtain the polymer.

Technical Field

The invention relates to the technical field of polyolefin catalysts, in particular to a catalyst system of IVB group metal ligand containing phthalazinone structure and application thereof in ethylene/1-olefin polymerization.

Background

Polyolefin elastomers are generally polyolefin materials produced by copolymerizing ethylene and propylene or other α -olefins (1-butene, 1-hexene, 1-octene, etc.) under certain conditions. Compared with general polyolefin resin, the higher the content of comonomer in the molecular chain of polyolefin elastomer, the lower the corresponding density, and because of the plasticity of plastics and the high elasticity of rubber, the polyolefin elastomer is one of the main development directions of high-end polyolefin materials at present.

The discovery of metallocene catalysts has driven the development of polyolefin elastomers, and nearly simultaneously, Dow chemical and Exxon have developed constrained geometry metallocene catalysts (CGC catalysts) for the production of ethylene-propylene rubber or ethylene-propylene-diene rubber. The catalyst has good copolymerization capability on high-grade alpha-olefin, and the copolymerization product has excellent mechanical property and processability. With the development of transition metal complex catalysts, random copolymers (POE) of ethylene and higher α -olefins (1-butene, 1-hexene, 1-octene, etc.) are receiving increasing attention from both academic and industrial fields. Compared with ethylene-propylene elastomers, the POE comonomer has the advantages of lower mole fraction of the comonomer, lower product density and more crystallizable polyethylene components (plastic phase) in molecular chains when the mass fraction of the comonomer is the same; at the same time, the longer branches of the higher alpha-olefin insertion form an amorphous copolymer (rubbery phase). Like ethylene propylene rubber, the polymer chain of POE consists of chemically stable saturated carbon-carbon single bonds, is nonpolar, and thus has good weather resistance and chemical corrosion resistance. Compared with cross-linked rubber, POE does not need to be vulcanized, shows high elasticity of the rubber at normal temperature, can be easily plasticized and molded like a thermoplastic numerical value at high temperature, is a thermoplastic elastomer with excellent performance, and is widely applied to the fields of automobile parts, sports equipment, household articles and the like.

In the 21 st century, new post-metallocene catalysts are more and more valued, and most of the post-metallocene catalysts adopt heteroatom ligands, so that the ligand structure design is more diversified, and many of the post-metallocene catalysts can be applied to the copolymerization of ethylene and alpha-olefin. The IVB metal catalyst of imine-amino ligand developed by Dow chemical company is mainly characterized by excellent comprehensive performance and industrial application prospect. Wherein, the complex of the following formula 1(Organometallics 2007,26,3896) can be isomerized at high temperature to generate a plurality of active centers; the subsequently developed Organometallics 2011, 30 and 1695 complex of the following formula 2 adopts an asymmetric iminenamine structure, and the catalyst has a stable structure at high temperature and high copolymerization activity and molecular weight. Recently, Dow chemical company developed a hafnium catalyst of bidentate amino quinoline ligand as shown in formula 3(Organometallics 2012,31,6244) based on the design concept of imine ligand, and the catalyst maintains high activity and narrow molecular weight distribution, and can increase the insertion amount of comonomer by increasing the concentration of comonomer.

However, the polymerization temperature reported for the catalysts of the above structures does not exceed 120 ℃ and is difficult to meet the industrial demand for solution polymerization, and therefore, it is necessary to further improve the activity of such catalysts at high temperatures.

Disclosure of Invention

In view of the above, the invention provides a group IVB metal complex containing a phthalazinone structure based on molecular structure design, and realizes that a catalyst composed of the complex catalyzes the polymerization reaction of ethylene and 1-octene at a higher temperature, and has the advantages of high catalytic activity, high product molecular weight, narrow molecular weight distribution and the like.

In order to realize the purpose of the invention, the invention adopts the following technical scheme:

the invention provides a catalyst system containing a group IVB metal ligand with a phthalazinone structure, which comprises a group IVB metal ligand with a phthalazinone structure shown as a formula I and a cocatalyst;

the cocatalyst is an aluminum-containing cocatalyst, the molar ratio of the aluminum element in the cocatalyst to the IV B group metal ligand containing the phthalazinone structure is (10-1000): 1, preferably (50-5000): 1, such as 100:1, 200: 1;

in formula I, M is selected from group IVB metals, preferably from titanium, zirconium or hafnium;

R₁～R₇each independently selected from hydrogen, halogen, alkyl, alkoxy, aryl, aralkyl, aralkoxy, aryloxy, silyl, imino; in some embodiments, the alkoxy group may be selected from methoxy or ethoxy; aralkyl may be selected from benzyl or p-methylbenzyl; the aralkyloxy can be selected from benzyloxy or p-tolyloxy; the imino group may be selected from N, N-dimethylamino or N, N-diethylamino.

In the present invention, the group IV B metal means a metal element in the IV subgroup in the chemical periodic table, for example, titanium, zirconium, hafnium.

In some preferred embodiments, the structure of formula I is shown as I containing a phthalazinone structureIn the group VB metal ligand, R₁～R₇Are respectively selected from hydrogen, halogen, alkyl, alkoxy, aryl and aralkyl; further preferably R₁～R₂Selected from halogen, alkyl, aralkyl; r₃～R₇Selected from halogen, alkyl, aralkyl.

In the IVB group metal ligand containing the phthalazinone structure and shown in the formula I, the skeleton structure comprises the phthalazinone structure which is stable at high temperature, and researchers of the invention find that the stability of the structure is higher than that of naphthalene ring and higher than that of benzene ring structure; meanwhile, in the metal ligand shown in the structure of the formula I, carbonyl and a benzene ring both have certain steric hindrance; the benzene ring and the naphthalene ring are positioned on a non-coplanar surface, so that the steric hindrance of the IVB group metal ligand containing the phthalazinone structure shown in the formula I is increased, and the stability of an active center is further increased; in addition, from the view point of electron cloud density, the benzene ring is used as an electron donating group to increase the electron cloud density of an active center in the IVB group metal ligand containing the phthalazinone structure shown in the formula I, so that the catalyst system has high catalytic activity. Research results show that when the IVB group metal ligand containing the phthalazinone structure is applied to the preparation process of the polyolefin elastomer, the IVB group metal ligand can still maintain high catalytic activity at a high temperature (150-200 ℃).

In the catalyst system of the present invention, the cocatalyst is selected from alumoxanes and/or modified alumoxanes; in some embodiments, the aluminoxane is selected from methylaluminoxane (abbreviated in the English to "MAO"); the modified aluminoxane is preferably selected from triisobutylaluminum-modified methylaluminoxane (abbreviated as "MMAO" in the English language).

The IVB group metal ligand containing the phthalazinone structure shown as the formula I in the invention is prepared by a method comprising the following steps:

1) dissolving a compound shown as a structure in a formula II in an organic solvent to obtain a reaction solution I, wherein the organic solvent is preferably tetrahydrofuran;

2) adding sodium hydride into the first reaction solution at-78-20 ℃, and reacting for 6-24 h;

3) continuously adding a compound shown in the following formula III structure into a reaction system at-78-20 ℃, and reacting for 6-24 h at-78-20 ℃ to obtain the IVB group metal ligand containing the phthalazinone structure;

preferably, filtering the product obtained by the reaction, washing and drying the obtained filter cake;

wherein R is₁～R₇Each independently selected from hydrogen, halogen, alkyl, alkoxy, aryl, aralkyl, aralkoxy, aryloxy, substituted silyl, imino; r₈～R₉Each independently selected from halogen, alkyl, aryl, aralkyl.

In some embodiments, the alkoxy groups R1-R9 in formulas II and III may be selected from methoxy or ethoxy; aralkyl may be selected from benzyl or p-methylbenzyl; the aralkyloxy can be selected from benzyloxy or p-tolyloxy; the imino group may be selected from N, N-dimethylamino or N, N-diethylamino.

In some preferred embodiments, in the compounds of the structures of formula II and III, R₁～R₂Selected from halogen, alkyl, aralkyl, R₃～R₇Selected from alkyl, aryl, aralkyl, R₈～R₉Selected from halogens.

In the step 2) of preparing the IVB group metal ligand containing the phthalazinone structure, sodium hydride is added into the obtained reaction liquid I under the protection of nitrogen atmosphere; in a specific example, after sodium hydride is added into the first reaction solution, the temperature of the reaction system is restored to-78-20 ℃ for reaction for 6-24 hours; preferably, the molar ratio of the sodium hydride added in the step 2) to the compound represented by the formula II in the step 1) is (1-1.5): 1, more preferably (1-1.1): 1, such as 1: 1.

In the step 3) of the preparation method, the molar ratio of the compound represented by the structure in the formula III to the compound represented by the structure in the formula II in the step 1) is 1 (2-2.1), preferably 1 (2-2.05), such as 1: 2.

The second aspect of the invention provides an application of a catalyst system containing an IVB group metal ligand with a phthalazinone structure, wherein in the presence of the catalyst system, ethylene and 1-octene are subjected to polymerization reaction to obtain a polymer;

wherein the catalytic activity of the catalyst system containing the IVB group metal ligand with the phthalazinone structure is 8 × 10⁷～1.2×10⁸g/(mol·M·h)；

The weight average molecular weight of the polymer was 1 × 10⁵～2.5×10⁵g/mol, the molecular weight distribution is 2.0-4.0;

in some preferred embodiments, the catalytic activity of the catalyst system containing the IVB group metal ligand with the phthalazinone structure at the temperature of 150-200 ℃ is 8 × 10⁷～1.2×10⁸g/(mol. M.h), e.g. a polymerization temperature of 200 ℃ the catalytic activity of the catalyst system can still reach 10⁷g/(mol. M. h). In the present invention, the unit "g/(mol. M.h)" of catalytic activity represents how many grams of polymer can be obtained per mole of metal ligand (M as an active center, selected from group IVB metals, such as titanium, zirconium or hafnium) in a unit time by catalytic polymerization.

In some specific embodiments, after drying the IVB group metal ligand containing a phthalazinone structure shown in the formula I, adding the cocatalyst and 1-octene, heating to 100-200 ℃, and adding ethylene for the polymerization reaction; in some embodiments, the ethylene is introduced at a pressure of 1 to 5MPa, preferably 2 to 4MPa, for example, 3 MPa; then 5-10% acid solution (such as 5%, 8% hydrochloric acid solution) is used to neutralize the reaction liquid of the polymerization reaction, and the product is separated out after slow precipitation; filtering the precipitated product, washing and drying to obtain the polymer; in some specific embodiments, the precipitated product is filtered, washed with water, and dried in vacuum at 50-100 ℃ to obtain the polymer. The specific operation of the polymerization process in the present invention is conventional in the art and will not be described herein.

In the specific preparation method, ethylene and 1-octene are polymerized for 5-60 min at 0-250 ℃ and 1-5 MPa; further preferably, the polymerization temperature is 100 to 200 ℃, such as 150 ℃, 180 ℃, 190 ℃; the pressure is 2-4 MPa, such as 3 MPa; the polymerization reaction is carried out for 10-40 min, such as 15min and 30 min.

The polymerization reaction can be carried out in an isoparaffin solvent, and for example, a commercially available Isopar E solvent can be used.

By adopting the technical scheme, the method has the following technical effects:

the invention provides a catalyst system containing a metal ligand of IVB group with a phthalazinone structure, wherein the skeleton structure of the metal ligand contains the phthalazinone structure with high stability at high temperature.

The catalyst system is applied to catalyzing the polymerization reaction of ethylene and 1-octene, and can show excellent catalytic activity and stability, so that the catalytic activity of the catalyst system reaches 8 × 10⁷～1.2×10⁸g/(mol. M. h), the weight average molecular weight of the obtained polyolefin elastomer reaches 1 × 10⁵～2.5×10⁵The molecular weight distribution is 2.0-4.0.

Detailed Description

In order to better understand the technical solution of the present invention, the following examples are further provided to illustrate the present invention, but the present invention is not limited to the following examples.