CN109320558B

CN109320558B - Preparation method of naphthol skeleton phenol-phosphine neutral nickel catalyst and application of catalyst in preparation of ethylene/vinyl polar monomer copolymer

Info

Publication number: CN109320558B
Application number: CN201811048801.XA
Authority: CN
Inventors: 李悦生; 王旭灵; 张艳平; 潘莉
Original assignee: Tianjin University
Current assignee: Tianjin University
Priority date: 2018-09-10
Filing date: 2018-09-10
Publication date: 2021-09-28
Anticipated expiration: 2038-09-10
Also published as: CN109320558A

Abstract

The invention relates to a preparation method of a naphthol skeleton phenol-phosphine neutral nickel catalyst and application of the catalyst in preparation of an ethylene/vinyl polar monomer copolymer. According to naphthol-phosphine ligands containing different R and Ar substituent groups, carrying out coordination reaction with a metal nickel source to obtain a series of naphthol-phosphine nickel complexes with different substituent groups. The phenol-phosphine nickel complex can be used as a neutral catalyst to initiate ethylene polymerization with high activity, wherein the homopolymerization activity of ethylene is as high as 2.9 multiplied by 10⁷g/(mol_NiH). The catalyst realizes the high-efficiency copolymerization of ethylene and vinyl polar monomer, and the copolymerization activity can reach 1.4 multiplied by 10⁵g/(mol_NiH). Through nuclear magnetic hydrogen spectrum calculation, the insertion rate of methyl acrylate can reach 6.5 mol% at most; the insertion rate of methyl methacrylate can reach 4.4mol percent at most.

Description

Preparation method of naphthol skeleton phenol-phosphine neutral nickel catalyst and application of catalyst in preparation of ethylene/vinyl polar monomer copolymer

Technical Field

The invention relates to synthesis of a naphthol skeleton phenol-phosphine nickel complex and application thereof in copolymerization of ethylene and vinyl polar monomers. Wherein the naphthol skeleton phenol-phosphine neutral nickel complex is used as an olefin polymerization catalyst for preparing linear polyethylene and ethylene/methyl (meth) acrylate random copolymer.

Background

Because of the characteristics of rich raw materials, low price, easy processing and forming, corrosion resistance and the like, the polyolefin becomes a polymer material with the largest output and the most extensive application in the world. However, most of the conventional polyolefins are nonpolar polymers, so that the inherent defects of hydrophilicity, colorability and poor compatibility with polar polymers seriously hinder the application of the polyolefins in many fields. The polyolefin is simply and effectively functionally modified, so that the surface polarity of the polyolefin can be greatly improved, the additional value of the polyolefin is increased, and the application range of the polyolefin is expanded.

In the last 50 s, Natta et al have recognized the important role of introducing functional groups into polyolefins. To date, there are four methods for the functionalization of polyolefins: high pressure free radical copolymerization, post reaction processing, reactive intermediates and direct coordination copolymerization. Although the high-pressure radical copolymerization method can realize the copolymerization of ethylene and polar monomers, the reaction conditions are severe, the equipment used is expensive, and the operation risk is large. In addition, the copolymer is a product of radical copolymerization, and the structure of the copolymer is complex and the performance is unstable. Generally, the post-reaction processing method has very low efficiency of functionalizing polyolefin, and the obtained functionalized product has a complex structure and non-uniform distribution of polar groups (mainly in a low molecular weight portion). As macromolecular free radicals on a polymer chain are very easy to generate beta-fission and mutual coupling reaction, the polymer is degraded or crosslinked, and the original excellent mechanical property and processing property of the polyolefin material are greatly damaged. The reactive intermediate method has the defects of multiple reaction steps, long time consumption and the like. In addition, due to the ubiquitous "macromolecular effect", the functional group conversion reaction rate and efficiency of the polymer are not as good as those of small organic molecules, thereby reducing the practical value of the method. In general, none of the above three approaches are particularly desirable for polyolefin functionalization.

The direct coordination copolymerization method refers to that olefin and polar monomer mildly realize polyolefin functionalization under the action of a coordination polymerization catalyst. Obviously, the method can directly synthesize the structurally-controllable side group functionalized polyolefin, and can realize the regulation and control of the position and the quantity of polar units on a polyolefin molecular chain. Unfortunately, the lone pair of electrons carried by heteroatoms such as O and N in the polar monomer are extremely easy to coordinate with the metal center of the catalyst, so that the catalyst is poisoned and inactivated. Therefore, the method has great challenges in practical application.

To date, most studies of direct coordination copolymerization methods have focused on preventing catalyst poisoning. There are two general approaches: firstly, a catalyst with lower oxygen affinity and more stable to hetero atoms is used; and secondly, sensitive polar components are protected to prevent catalyst poisoning. Recently, random copolymerization of olefin monomers with various polar monomers has been successfully achieved by using newly developed heteroatom-tolerant late transition metal catalysts, either to sterically hinder and electronically protect the polar groups, or to increase the steric hindrance around the central atom on the catalyst.

Compared with the pre-transition metal catalysts such as titanium, zirconium and the like, the post-transition metal catalysts such as nickel, palladium and the like have weaker oxygen affinity, so that the catalysts have strong tolerance to polar groups and are suitable for catalyzing direct copolymerization of olefin and polar monomers to prepare functionalized polyolefin. In the last 90 s, the Brookhart task group reported for the first time an alpha-diimine cationic palladium catalyst and successfully realized the direct copolymerization of ethylene and acrylate monomers. However, due to the obvious Chain Walking of the catalyst (Chain Walking), the obtained polymer has higher branching degree. In addition, the neutral palladium complex of phosphine sulfonate is another classical catalyst which can be used for the direct copolymerization of polar monomers and ethylene, and has attracted much attention since the first report by Pugh topic group in 2002. The copolymerization action and the catalytic mechanism of ethylene and polar monomers (methyl acrylate, vinyl acetate, acrylonitrile, vinyl fluoride and vinyl ethyl ether) initiated by the catalyst are intensively researched by a plurality of subject groups such as Mecking, Nozaki, Jordon and the like, and the development of the late transition metal catalyst is further promoted. Unlike the alpha-diimine cationic palladium catalyst, the neutral palladium phosphine sulfonate catalyst can produce linear functionalized polyolefin through coordination polymerization, and the polar unit is located in the middle of the main chain.

At present, a catalyst capable of realizing direct coordination polymerization of ethylene and vinyl polar monomers is mainly a palladium complex, but metal palladium is expensive and is not suitable for industrial popularization. The late transition metal nickel of the same family is relatively cheap, and is beneficial to industrial application. Therefore, the nickel-based catalyst is becoming a hot point for direct copolymerization of ethylene and vinyl polar monomers.

In view of the fact that the research of neutral nickel complexes of benzene ring frameworks is more, the invention develops a new method based on naphthol frameworks to synthesize a series of naphthol framework phenol-phosphine neutral nickel complexes, successfully realizes the direct coordination copolymerization of ethylene and methyl (methyl) acrylate, and prepares a linear polymer with polar units positioned in the chain and at the chain end.

Disclosure of Invention

The invention aims to provide a naphthol skeleton phenol-phosphine neutral nickel complex, a preparation method thereof and an implementation method thereof for catalyzing direct coordination copolymerization of ethylene and vinyl polar monomers. The catalyst has extremely high ethylene homopolymerization activity and excellent polar monomer tolerance, and can be used for preparing linear polyethylene and ethylene/methyl (meth) acrylate random copolymer. These characteristics make such catalysts promising in the field of ethylene and polar monomer copolymerization.

The technical scheme of the invention is as follows:

a naphthol skeleton phenol-phosphine neutral nickel catalyst, the structural formula of which is as follows:

wherein: the R group is hydrogen, an alkane, a silane or an aromatic hydrocarbon group; ar (Ar)₁The radical being phenyl, cyclohexyl or 2- (C)₆H₅)-C₆H₄；Ar₂The radical being phenyl, cyclohexyl or 2- (C)₆H₅)-C₆H₄。

Preferably, R is hydrogen, methyl, tert-butyl, trimethylsilyl, phenyl, 3, 5-dimethylphenyl or 3, 5-bis (trifluoromethyl) phenyl.

The synthesis method of the naphthol skeleton phenol-phosphine neutral nickel catalyst is characterized in that a naphthol-phosphine ligand and a metal nickel source are respectively dissolved in a good solvent under the atmosphere of argon or nitrogen, and then a ligand solution is dropwise added into a metal nickel source solution; reacting at room temperature for 8-10 h, filtering, and removing the solvent to obtain the naphthol-phosphine neutral nickel catalyst shown in the formula I.

The metallic nickel source is preferably nickel dimethyl bipyridine (Py)₂NiMe₂) (ii) a The good solvent can be toluene or diethyl ether, and toluene is preferred; the molar ratio of the metallic nickel source to the ligand is preferably 1.1-1.3.

The structure of the naphthol-phosphine ligand used in the invention is shown as formula II:

the structure is shown as formula II, and when R is H, the preparation method of the ligand structure has been reported in the literature.

When R is not H, the synthesis method of the naphthol-phosphine ligand is characterized in that alpha-naphthol, iodide with R substituent and an alkaline substance are simultaneously dissolved in N, N-dimethylformamide under the atmosphere of argon or nitrogen, and the R substituent is introduced into 8-position of the alpha-naphthol through coupling reaction under the catalytic action of palladium chloride. Then reacting with dihydropyran to obtain the product a with tetrahydropyran group. Then carry Ar₁And Ar₂And (3) dropwise adding the phosphine salt solution of the substituent group into the solution of the product a, and reacting in an ice-water bath for 4-6 h to obtain the naphthol-phosphine ligand with the structure shown in the formula II.

The alkaline substance can be potassium carbonate or cesium carbonate, and is preferably cesium carbonate; the coupling reaction temperature is preferably 115 ℃; the coupling reaction time is preferably 8-12 h.

The naphthol skeleton phenol-phosphine neutral nickel complex is used for catalyzing ethylene homopolymerization or ethylene/vinyl polar monomer copolymerization.

The naphthol skeleton phenol-phosphine neutral nickel complex is used to catalyze the homopolymerization of ethylene and is characterized in that the ethylene and a catalyst are subjected to high-pressure solution polymerization reaction in an inert solvent. The inert solvent is preferably toluene. After the reaction was complete, the polymer was precipitated, filtered and dried.

The naphthol skeleton phenol-phosphine neutral nickel complex is used in catalyzing homopolymerization of ethylene and has homopolymerization activity as high as 2.9X 10⁷g/(mol_NiH), which is a major breakthrough for the phosphine-oxygen neutral nickel complex to catalyze ethylene homopolymerization. High-temperature stability is excellent, and the polymerization temperature can still reach 10 ℃ under the polymerization condition of 90 DEG C⁷g/(mol_Ni·h)。

The naphthol skeleton phenol-phosphine neutral nickel complex is used to catalyze the direct coordination copolymerization of ethylene and vinyl polar monomer and features that ethylene, comonomer and catalyst are high pressure solution polymerized in inert solvent. The inert solvent is preferably toluene. After the reaction was complete, the polymer was precipitated, filtered and dried.

The characteristic of the naphthol skeleton phenol-phosphine neutral nickel complex in the invention that the direct coordination copolymerization of ethylene and vinyl polar monomer is catalyzed is that the highest copolymerization activity can reach 1.4 multiplied by 10⁵g/(mol_NiH), which is a great breakthrough of catalyzing the copolymerization of ethylene and methyl acrylate by the phosphine-oxygen neutral nickel complex.

Preferably, the comonomer is acrylate polar monomer; the molar ratio of the comonomer to the catalyst is (0-1000): 1; the dosage of the catalyst is 5-30 mu mol; the inert solvent is toluene, xylene or decalin; the ethylene pressure during the reaction is 1-30 bar; the polymerization temperature is 30-100 ℃; the required polymerization time is 10-60 min; the precipitant is methanol, ethanol or acetone.

The invention relates to a naphthol skeleton phenol-phosphine neutral nickel catalyst, a preparation method thereof and application thereof in ethylene/vinyl polar monomer copolymerization. Firstly, naphthol-phosphine ligands containing different R and Ar substituent groups are prepared, and then the naphthol-phosphine ligands and a metal nickel source are subjected to coordination reaction to obtain a series of naphthol-phosphine nickel complexes with different substituent groups. The X-ray single crystal diffraction shows that the molecular structure of the complex is in a plane quadrangle. The phenol-phosphine nickel complex can be used as neutralThe catalyst single component initiates ethylene polymerization with high activity, wherein the ethylene homopolymerization activity is as high as 2.9 multiplied by 10⁷g/(mol_NiH). Nuclear magnetic analysis shows that the obtained polymer is a linear structure; GPC outflow curve shows that the molecular weight of the obtained polymer is 0.9-338 multiplied by 10³Is adjustable. In addition, the catalyst can also realize the high-efficiency copolymerization of ethylene and vinyl polar monomer, wherein the ethylene and vinyl polar monomer comprise mono-substituted methyl acrylate and 1, 1-disubstituted methyl methacrylate, and the copolymerization activity can reach 1.4 multiplied by 10⁵g/(mol_NiH). By adjusting the steric hindrance on the phosphorus atom, the proportion of the comonomer inserted into the molecular chain and at the molecular chain end of the copolymer can be adjusted and controlled. As the steric hindrance increases, the proportion of the copolymerized units located in the molecular chain increases. The polymer prepared by the invention has a linear structure; the polar units are randomly distributed in the polymer chain and at the chain ends; the insertion rate of the polar monomer is 0 to 6.5 mol%. Through nuclear magnetic hydrogen spectrum calculation, the insertion rate of methyl acrylate can reach 6.5 mol% at most; the insertion rate of methyl methacrylate can reach 4.4mol percent at most.

Drawings

FIG. 1 is a molecular structural diagram of complex A-3 in example 9 of the present invention;

FIG. 2 is a drawing showing linear polyethylene in example 14 of the present invention¹H NMR spectrum;

FIG. 3 is a GPC outflow curve of linear polyethylene in example 17 of the present invention;

FIG. 4 is a drawing showing a linear ethylene/methyl acrylate random copolymer in example 20 of the present invention¹H NMR spectrum;

FIG. 5 is a drawing showing a linear ethylene/methyl methacrylate random copolymer in example 25 of the present invention¹H NMR spectrum;

FIG. 6 is a DSC curve of a linear ethylene/methyl acrylate random copolymer of example 17 of the present invention;

FIG. 7 is a DSC curve of a linear ethylene/methyl acrylate random copolymer in example 23 of the present invention.

Detailed Description

In order to fully illustrate the present invention, the embodiments of the present invention will be described with reference to the detailed description and accompanying drawings. It is to be understood that such description is merely illustrative of the features and advantages of the present invention, and is not intended to limit the scope of the claims.

The operations involved in the synthesis of the catalyst are carried out by those skilled in the art, except for the specific details, in an MBraun glove box or under nitrogen protection using standard Schlenk techniques, and the solvents involved in the present invention are anhydrous and oxygen-free solvents.

All moisture and oxygen sensitive operations during homopolymerization of ethylene or copolymerization of ethylene with polar monomers are carried out by a person skilled in the art under nitrogen protection in an MBraun glove box or by means of standard Schlenk techniques.

The obtained polymer was subjected to related tests, the microstructure of the polymer was determined by nuclear magnetic resonance spectroscopy, the melting temperature of the polymer was determined by differential thermal analysis, and the molecular weight distribution index of the polymer were determined by gel chromatography. In which the polymer is¹H and¹³c NMR was measured at 120 ℃ by a Bruker-400 NMR spectrometer using internal standard TMS and deuterated 1,1,2, 2-tetrachloroethane as solvent. The polymer melting temperature was measured by differential scanning calorimetry (TA index Q2000DSC), the rising/falling rate was 10 ℃/min, and the atmosphere was nitrogen. Gel chromatography was performed by using PL GPC-220 type gel permeation chromatograph. The tester is RI-Laser, the packed column is Plgel 10 μm MIXED-BLS, 1,2, 4-Trichlorobenzene (TCB) is used as solvent (0.05 wt% of 2, 6-di-tert-butyl-4-methylphenol is added as antioxidant), the testing temperature is 150 ℃, the flow rate is 1.0mL/min, and PL EasiCal PS-1 is used as a standard sample.

Catalyst, substituent R, Ar, described in the present invention₁And Ar₂Preferably then comprising the following structures A1-D4:

the specific scheme of the preparation method of the naphthol skeleton phenol-phosphine neutral nickel catalyst is as follows:

the device is mainly divided into two parts: (1) synthesizing a ligand; (2) and (3) synthesizing the complex.

The preparation method is detailed by taking the catalyst with the structure shown by A-1, A-2, A-3, A-4, B-1 and C-1 as an example.

Example 1:

the A-1 ligand is naphthol-phosphine L1, and the structural formula is as follows:

synthesis of L1:

alpha-naphthol (11.5g,50mmol) and dihydropyran were stirred under nitrogen atmosphere at room temperature for 10h to obtain product b with tetrahydropyran group. This was dissolved in 100mL of tetrahydrofuran and stabilized at-78 ℃ for 5 minutes, and an n-BuLi solution (25mL,60mmol) was added dropwise and reacted for 0.5h, followed by gradual return to room temperature. The reaction was continued for 2h to give a large amount of white precipitate c. 10.7mL of diphenylphosphine chloride (PPh)₂Cl) is uniformly dispersed in 20mL tetrahydrofuran, and the mixture is added into the original reaction system dropwise in an ice-water bath, slowly heated to room temperature, and stirred for reaction overnight. TLC was monitored to the end of the reaction, quenched with water, the organic phase extracted with ether, the resulting organic phase concentrated to 100mL, frozen for deoxygenation, 15mL concentrated HCl added under nitrogen, reacted for 5h, and the reaction was followed by TLC. Adding NaHCO₃Neutralizing with water, quenching with water, extracting the organic phase with diethyl ether, anhydrous MgSO₄Drying, filtering, concentrating and flash column chromatography gave 10.2g of white solid in 61% yield.

Example 2:

the A-2 ligand is naphthol-phosphine L2, and the structural formula is as follows:

synthesis of L2:

alpha-naphthol (7.2g,50mmol), iodobenzene (12.3g,60mmol), and cesium carbonate (19.5g,60mmol) were dissolved in 150mL of DMF under a nitrogen atmosphere, and palladium chloride (0.13g,0.75mmol) was added as a catalyst, followed by heating at 115 ℃ and refluxingFlow 12h, TLC monitored the progress of the reaction. After the reaction is finished and the temperature is reduced to room temperature, the organic phase is extracted by ethyl ether and anhydrous MgSO₄Drying, filtering and concentrating. Column chromatography to obtain the product d as dark brown oil. The reaction solution and dihydropyran are stirred and reacted for 10h at room temperature to obtain pale yellow solid e with tetrahydropyran groups.

Intermediate e (9.2g,30mmol) was dissolved in 50mL of diethyl ether under nitrogen, stabilized in an ice-water bath for 5 minutes, and n-BuLi solution (14mL,33mmol) was added dropwise, reacted for 0.5h and gradually returned to room temperature. The reaction was continued for 4h to give a large amount of white precipitate f. 6.5mL of diphenylphosphine chloride (PPh)₂Cl) is evenly dispersed in 10mL of diethyl ether, and the mixture is added into the original reaction system dropwise in an ice water bath, slowly heated to room temperature, stirred and reacted overnight. TLC was monitored to the end of the reaction, quenched with water, the organic phase extracted with ether, the resulting organic phase concentrated to 100mL, frozen for deoxygenation, 5mL concentrated HCl added under nitrogen, reacted for 5h, and the reaction was followed by TLC. Adding NaHCO₃Neutralizing with water, quenching with water, extracting the organic phase with diethyl ether, anhydrous MgSO₄Drying, filtering, concentrating and flash column chromatography gave 7.8g of white solid in 64% yield.

Example 3:

the A-3 ligand is naphthol-phosphine L3, and the structural formula is as follows:

synthesis of L3:

alpha-naphthol (7.2g,50mmol), 3, 5-dimethyliodobenzene (13.9g,60mmol), cesium carbonate (19.5g,60mmol) were dissolved in 150mL of DMF under a nitrogen atmosphere, palladium chloride (0.13g,0.75mmol) was added as a catalyst, heated at 115 ℃ under reflux for 12h, and the progress of the reaction was monitored by TLC. After the reaction is finished, the temperature is reduced to room temperature, and the organic phase is extracted by ethyl ether and anhydrous MgSO₄Drying, filtering and concentrating. Column chromatography gave g as a dark brown oil. The mixture is stirred and reacted with dihydropyran for 10h at room temperature to obtain pale yellow solid h with tetrahydropyran groups.

Intermediate h (9.9g,30mmol) was dissolved under nitrogenDissolving in 50mL of diethyl ether, stabilizing in an ice-water bath for 5 minutes, dropwise adding n-BuLi solution (14mL,33mmol), reacting for 0.5h, and gradually returning to room temperature. The reaction was continued for 4h to give a large amount of white precipitate i. 6.5mL of diphenylphosphine chloride (PPh)₂Cl) is evenly dispersed in 10mL of diethyl ether, and the mixture is added into the original reaction system dropwise in an ice water bath, slowly heated to room temperature, stirred and reacted overnight. TLC was monitored to the end of the reaction, quenched with water, the organic phase extracted with ether, the resulting organic phase concentrated to 100mL, frozen for deoxygenation, 5mL concentrated HCl added under nitrogen, reacted for 5h, and the reaction was followed by TLC. Adding NaHCO₃Neutralizing with water, quenching with water, extracting the organic phase with diethyl ether, anhydrous MgSO₄Drying, filtering, concentrating and flash column chromatography gave 7.5g of white solid in 58% yield.

Example 4:

the A-4 ligand is naphthol-phosphine L4, and the structural formula is as follows:

synthesis of L4:

under a nitrogen atmosphere, α -naphthol (7.2g,50mmol), 3, 5-bis (trifluoromethyl) iodobenzene (20.4g,60mmol), cesium carbonate (19.5g,60mmol) were dissolved in 200mL of DMF, palladium chloride (0.13g,0.75mmol) was added as a catalyst, and the mixture was heated under reflux at 115 ℃ for 12 hours, and the progress of the reaction was monitored by TLC. After the reaction is finished, the temperature is reduced to room temperature, and the organic phase is extracted by ethyl ether and anhydrous MgSO₄Drying, filtering and concentrating. Column chromatography gave product j as a dark brown oil. The mixture is stirred and reacted with dihydropyran for 10h at room temperature to obtain pale yellow solid k with tetrahydropyranyl group.

Intermediate k (13.2g,30mmol) was dissolved in 50mL of diethyl ether under nitrogen, stabilized in an ice-water bath for 5 minutes, and n-BuLi solution (14mL,33mmol) was added dropwise, reacted for 0.5h and gradually returned to room temperature. The reaction was continued for 4h to give a large amount of white precipitate l. 6.5mL of diphenylphosphine chloride (PPh)₂Cl) is evenly dispersed in 10mL of diethyl ether, and the mixture is added into the original reaction system dropwise in an ice water bath, slowly heated to room temperature, stirred and reacted overnight. TLC monitoring toAfter the reaction, quenching with water, extracting the organic phase with diethyl ether, concentrating the obtained organic phase to 100mL, freezing for circulating deoxygenation, adding 5mL concentrated hydrochloric acid under nitrogen atmosphere, reacting for 5h, and tracking the reaction by TLC. Adding NaHCO₃Neutralizing with water, quenching with water, extracting the organic phase with diethyl ether, anhydrous MgSO₄Drying, filtering, concentrating and flash column chromatography gave 8.1g of white solid with 50% yield.

Example 5:

the B-1 ligand is naphthol-phosphine L5, and the structural formula is as follows:

synthesis of L5:

7.0mL of phenyl phosphine dichloride was dispersed in 20mL of diethyl ether under nitrogen atmosphere and stabilized at-78 ℃ for 5 minutes, and 2-biphenylmagnesium bromide (100mL,50mmol) was added dropwise thereto and reacted for 0.5h and then slowly warmed to room temperature. And continuing the reaction for 2 hours, wherein a large amount of white precipitates m are generated, namely the phosphonium salt. Product b from example 1 (11.5g,50mmol) was dissolved in 50mL tetrahydrofuran and stabilized at-78 deg.C for 5 minutes, n-BuLi solution (25mL,60mmol) was added dropwise and the reaction was allowed to gradually return to room temperature after 0.5 h. And after the reaction is continued for 2 hours, carrying out ice-water bath, dropwise introducing the newly prepared phosphonium salt into the lithium salt solution, reacting for 0.5 hour, slowly heating to room temperature, and stirring for reacting overnight. TLC was monitored to the end of the reaction, quenched with water, the organic phase extracted with ether, the resulting organic phase concentrated to 100mL, frozen for deoxygenation, 10mL concentrated HCl added under nitrogen, reacted for 5h, and the reaction was followed by TLC. Adding NaHCO₃Neutralizing with water, quenching with water, extracting the organic phase with diethyl ether, anhydrous MgSO₄Drying, filtering, concentrating and flash column chromatography gave 15g of white solid in 53% yield.

Example 6:

the C-1 ligand is naphthol-phosphine L6, and the structural formula is as follows:

synthesis of L6:

2-Bromobiphenyl (11.7g,50mmol) was uniformly dispersed in 50mL of diethyl ether under a nitrogen atmosphere and stabilized at-78 ℃ for 5 minutes, and n-BuLi solution (25mL,60mmol) was added dropwise. After 1.5h of reaction, dichloro (diethylamino) phosphine (4.4g,25mmol) was added dropwise. After 0.5h of reaction, the temperature was slowly raised to room temperature and the reaction was stirred overnight. TLC was monitored to the end of the reaction, quenched with water and the organic phase extracted with ether. Anhydrous MgSO (MgSO)₄Drying, filtering, concentrating and carrying out column chromatography to obtain a light yellow solid n.

Under nitrogen atmosphere, solid n (12.2g,30mmol) was dissolved in 30mL of diethyl ether, stabilized in an ice-water bath for 5 minutes, and 10mL of ethyl ether hydrochloride solution was added dropwise. After 5h of reaction, TLC monitoring indicated the reaction was complete. Vacuum filtration, ether washing and vacuum solvent removal to obtain yellow oily intermediate o.

Product b from example 1 (6.9g,30mmol) was dissolved in 50mL tetrahydrofuran and stabilized at-78 deg.C for 5 minutes, n-BuLi solution (15mL,36mmol) was added dropwise and the reaction was allowed to gradually return to room temperature after 0.5 h. After the reaction is continued for 2 hours, the mixture is subjected to ice-water bath, the ether solution of the intermediate product o is dropwise introduced into the lithium salt solution, the temperature is slowly raised to the room temperature after the reaction is carried out for 0.5 hour, and the reaction is stirred overnight. TLC was monitored to the end of the reaction, quenched with water, the organic phase extracted with ether, the resulting organic phase concentrated to 100mL, frozen for deoxygenation, 10mL concentrated HCl added under nitrogen, reacted for 5h, and the reaction was followed by TLC. Adding NaHCO₃Neutralizing with water, quenching with water, extracting the organic phase with diethyl ether, anhydrous MgSO₄Drying, filtering, concentrating and flash column chromatography gave 6.2g of a pink solid with a yield of 43%.

The synthesis steps of the catalyst are as follows:

example 7:

the structural formula of the complex A-1 is as follows:

the synthesis steps are as follows:

ligand L1(0.33g, 1mmol) and metallic nickel source (Py) were placed under nitrogen atmosphere₂NiMe₂) (0.27g, 1.1mmol) were dissolved in toluene, respectively. And then, dropwise adding the ligand solution into the metal nickel source solution, violently stirring, reacting at room temperature for 10 hours, and filtering to obtain a brown yellow solution. The solvent was removed in vacuo to give 0.40g of neutral nickel naphthol-phosphine complex of formula A-1 in 83% yield.

Example 8:

the structural formula of the complex A-2 is as follows:

the synthesis steps are as follows:

ligand L2(0.41g, 1mmol) and metallic nickel source (Py) were placed under nitrogen atmosphere₂NiMe₂) (0.27g, 1.1mmol) were dissolved in diethyl ether, respectively. And then, dropwise adding the ligand solution into the metal nickel source solution, violently stirring, reacting at room temperature for 10 hours, and filtering to obtain a brown yellow solution. The solvent was removed in vacuo to give 0.42g of neutral nickel naphthol-phosphine complex of formula A-2 in 76% yield.

Example 9:

the structural formula of the complex A-3 is as follows:

the synthesis steps are as follows:

ligand L3(0.43g, 1mmol) and metallic nickel source (Py) were placed under nitrogen atmosphere₂NiMe₂) (0.27g, 1.1mmol) were dissolved in diethyl ether, respectively. And then, dropwise adding the ligand solution into the metal nickel source solution, violently stirring, reacting at room temperature for 10 hours, and filtering to obtain a brown yellow solution. The solvent was removed in vacuo to give 0.39g of neutral nickel naphthol-phosphine complex of formula A-3 in 67% yield. Molecular structure thereofThe figure is shown in figure 1 of the accompanying drawings.

Example 10:

the structural formula of the complex A-4 is as follows:

the synthesis steps are as follows:

ligand L4(0.54g, 1mmol) and metallic nickel source (Py) were placed under nitrogen atmosphere₂NiMe₂) (0.27g, 1.1mmol) were dissolved in toluene, respectively. And then, dropwise adding the ligand solution into the metal nickel source solution, violently stirring, reacting at room temperature for 10 hours, and filtering to obtain a brown yellow solution. The solvent was removed in vacuo to give 0.35g of neutral nickel naphthol-phosphine complex of formula A-4 in 51% yield.

Example 11:

the structural formula of the complex B-1 is as follows:

the synthesis steps are as follows:

ligand L5(0.41g, 1mmol) and metallic nickel source (Py) were placed under nitrogen atmosphere₂NiMe₂) (0.27g, 1.1mmol) were dissolved in toluene, respectively. And then, dropwise adding the ligand solution into the metal nickel source solution, violently stirring, reacting at room temperature for 10 hours, and filtering to obtain a brown yellow solution. The solvent was removed in vacuo to give 0.44g of neutral nickel naphthol-phosphine complex of formula B-1 in 79% yield.

Example 12:

the structural formula of the complex C-1 is as follows:

the synthesis steps are as follows:

ligand L6(0.48g, 1mmol) and metallic nickel source (Py) were placed under nitrogen atmosphere₂NiMe₂)(0.27g，1.1mmol)Separately dissolved in toluene. And then, dropwise adding the ligand solution into the metal nickel source solution, violently stirring, reacting at room temperature for 10 hours, and filtering to obtain a brown yellow solution. The solvent was removed in vacuo to give 0.47g of neutral nickel naphthol-phosphine complex of formula C-1 in 74% yield.

In the invention, the coordination compound A-1, A-2, A-3, A-4, B-1 and B-2 is utilized to successfully realize ethylene homopolymerization and copolymerization of ethylene and vinyl polar monomer without the help of any cocatalyst. The specific embodiment is as follows:

example 13:

the catalyst used in this example was complex a-1, and the polyethylene produced was linear polyethylene, most of which had a terminal structure of vinyl.

The specific steps of the complex A-1 in this example for catalyzing ethylene polymerization are as follows:

(1) in a dry 1L autoclave, 500mL of toluene was added under vacuum, and the mixture was stirred for 5 minutes to stabilize the reaction temperature at 50 ℃. 20. mu. mol of a toluene solution of complex A-1 were added, 10bar of ethylene gas were immediately introduced and the reaction was stirred vigorously for 20 minutes. Condensed water is introduced during the reaction process to control the reaction temperature to 50 ℃.

(2) After the polymerization reaction is finished, the ethylene gas in the kettle is emptied, and then the reaction liquid in the kettle is poured into 1L of ethanol for sedimentation. Then filtering, washing and vacuum drying to obtain the polyethylene.

And performing nuclear magnetic analysis, thermal analysis and molecular weight characterization on the product. The test results show that the product obtained in the inventive example has a structure in accordance with P1, wherein the polyethylene has a melting point of 128 ℃ and a molecular weight of 20.9X 10³。

Example 14:

the catalyst used in this example was complex a-2, and the polyethylene produced was linear polyethylene, most of which had a terminal structure of vinyl.

The specific steps of the complex A-2 in this example for catalyzing ethylene polymerization are as follows:

(1) in a dry 1L autoclave, 500mL of toluene was added under vacuum, and the mixture was stirred for 5 minutes to stabilize the reaction temperature at 70 ℃. 20. mu. mol of complex A-2 in toluene were added, 10bar of ethylene gas were immediately introduced and the reaction was stirred vigorously for 20 minutes. During the reaction, condensed water was introduced to control the reaction temperature to 70 ℃.

The polymerization activity obtained in this example was as high as 10⁷g/(mol_NiH). And performing nuclear magnetic analysis, thermal analysis and molecular weight characterization on the product. Wherein nuclear magnetism¹The H NMR spectrum is shown in figure 2. The test results show that the product obtained in the inventive example has a structure in accordance with P1, wherein the polyethylene has a melting point of 119 ℃ and a molecular weight of 6.1X 10³。

Example 15:

the catalyst used in this example was complex a-3, and the polyethylene produced was linear polyethylene, most of which had a terminal structure of vinyl.

The specific steps of the complex A-3 in this example for catalyzing ethylene polymerization are as follows:

(1) in a dry 1L autoclave, 500mL of toluene was charged under vacuum, and the mixture was stirred for 5 minutes to stabilize the reaction temperature at 90 ℃. 20. mu. mol of a toluene solution of complex A-3 were added, 10bar of ethylene gas were immediately introduced and the reaction was stirred vigorously for 20 minutes. Condensed water is introduced into the reaction process to control the reaction temperature to 90 ℃ as much as possible.

And performing nuclear magnetic analysis, thermal analysis and molecular weight characterization on the product. The test results show that the product obtained in the inventive example has a structure in accordance with P1, wherein the polyethylene has a melting point of 115 ℃ and a molecular weight of 5.2X 10³。

Example 16:

the catalyst used in this example was complex a-4, and the polyethylene produced was linear polyethylene, most of which had a terminal structure of vinyl.

The specific steps of the complex A-4 in this example for catalyzing ethylene polymerization are as follows:

(1) in a dry 1L autoclave, 500mL of toluene was charged under vacuum, and the mixture was stirred for 5 minutes to stabilize the reaction temperature at 90 ℃. 20. mu. mol of complex A-4 in toluene were added, 10bar of ethylene gas were then passed through immediately and the reaction was stirred vigorously for 20 minutes. Condensed water is introduced into the reaction process to control the reaction temperature to 90 ℃ as much as possible.

And performing nuclear magnetic analysis, thermal analysis and molecular weight characterization on the product. The test results show that the product obtained in the inventive example has a structure in accordance with P1, wherein the polyethylene has a melting point of 110 ℃ and a molecular weight of 0.9X 10³。

Example 17:

in this example, the catalyst used was Complex B-1, and the polyethylene produced was a linear high molecular weight polyethylene

The specific steps of the complex B-1 in the example for catalyzing ethylene polymerization are as follows:

(1) in a dry 1L autoclave under vacuum, 500mL of toluene was added and stirred for 5 minutes to stabilize the reaction temperature at 50 ℃. 20. mu. mol of complex B-1 in toluene were added, 10bar of ethylene gas were then passed through immediately and the reaction was stirred vigorously for 20 minutes. Condensed water is introduced during the reaction process to control the reaction temperature to 50 ℃.

And performing nuclear magnetic analysis, molecular weight characterization and DSC analysis on the product. Wherein the GPC outflow curve is shown in figure 3, and the DSC curve is shown in figure 6. The test results show that the product obtained in the inventive example has a structure in accordance with P2, wherein the polyethylene has a melting point of 135 ℃ and a molecular weight of 108.5X 10³. Compared with the catalyst using phenyl as the substituent on the P atom, the molecular weight is obviously improved.

Example 18:

in this example, the catalyst used was complex C-1, and the polyethylene produced was a linear high molecular weight polyethylene.

The specific steps of the complex C-1 in the example for catalyzing ethylene polymerization are as follows:

(1) in a dry 1L autoclave under vacuum, 500mL of toluene was added and stirred for 5 minutes to stabilize the reaction temperature at 50 ℃. Mu. mol of a solution of complex C-1 in toluene were added, 10bar of ethylene gas were then passed through immediately and the reaction was stirred vigorously for 20 minutes. During the reaction, condensed water was introduced to control the reaction temperature to 70 ℃.

And performing nuclear magnetic analysis, thermal analysis and molecular weight characterization on the product. The test results show that the product obtained in the inventive example has a structure in accordance with P2, wherein the polyethylene has a melting point of 138 ℃ and a molecular weight of 132.3X 10³. Compared with the catalyst using phenyl as the substituent on the P atom, the molecular weight is obviously improved.

Example 19:

the catalyst used in this example was complex A-1, and the polymer produced was an ethylene/methyl acrylate random copolymer.

In this example, the specific steps of the complex A-1 catalyzing the copolymerization of ethylene and methyl acrylate are as follows:

(1) 500mL of toluene was added to a dry 1L autoclave under an ethylene atmosphere, and the mixture was stirred for 5 minutes to stabilize the reaction temperature at 70 ℃. Adding 50mmol of methyl acrylate toluene solution, then quickly adding 50 mu mol of complex A-1 toluene solution, immediately introducing 20bar of ethylene gas, and violently stirring for reacting for 60 minutes;

(2) after the polymerization reaction is finished, the ethylene gas in the kettle is emptied, and then the reaction liquid in the kettle is poured into 1L of methanol for sedimentation. Then filtering, washing and vacuum drying to obtain the ethylene/methyl acrylate random copolymer.

And performing nuclear magnetic analysis, thermal analysis and molecular weight characterization on the product. The test results show that the structures of the products obtained in the examples of the invention are consistent with those of P3 and P4. Wherein the insertion rate of methyl acrylate is 4.4 mol%, the melting temperature of the copolymer is 110 ℃, and the molecular weight is 2.0 × 10³。

Example 20:

the catalyst used in this example was complex A-2, and the polymer produced was an ethylene/methyl acrylate random copolymer.

In this example, the specific steps of the complex A-2 catalyzing the copolymerization of ethylene and methyl acrylate are as follows:

(1) 500mL of toluene was added to a dry 1L autoclave under an ethylene atmosphere, and the mixture was stirred for 5 minutes to stabilize the reaction temperature at 70 ℃. Adding 50mmol of methyl acrylate toluene solution, then quickly adding 50 mu mol of complex A-2 toluene solution, immediately introducing 20bar of ethylene gas, and violently stirring for reacting for 60 minutes;

And performing nuclear magnetic analysis, thermal analysis and molecular weight characterization on the product. Wherein nuclear magnetism¹The H NMR spectrum is shown in figure 4. The test results show that the structures of the products obtained in the examples of the invention are consistent with those of P3 and P4. Wherein the insertion rate of methyl acrylate is 3.8 mol%, the melting temperature of the copolymer is 108 ℃, and the molecular weight is 1.2 multiplied by 10³。

Example 21:

the catalyst used in this example was complex A-3, and the polymer produced was an ethylene/methyl acrylate random copolymer.

In this example, the specific steps of the complex A-3 catalyzing the copolymerization of ethylene and methyl acrylate are as follows:

(1) 500mL of toluene was added to a dry 1L autoclave under an ethylene atmosphere, and the mixture was stirred for 5 minutes to stabilize the reaction temperature at 70 ℃. Adding 50mmol of methyl acrylate toluene solution, then quickly adding 50 mu mol of complex A-3 toluene solution, immediately introducing 20bar of ethylene gas, and violently stirring for reacting for 60 minutes;

And performing nuclear magnetic analysis, thermal analysis and molecular weight characterization on the product. The test results show that the structures of the products obtained in the examples of the invention are consistent with those of P3 and P4. Wherein the insertion rate of methyl acrylate is 4.0 mol%, the melting temperature of the copolymer is 106 ℃, and the molecular weight is 1.2 multiplied by 10³。

Example 22:

the catalyst used in this example was complex A-4, and the polymer produced was an ethylene/methyl acrylate random copolymer.

In this example, the specific steps of the complex A-4 catalyzing the copolymerization of ethylene and methyl acrylate are as follows:

(1) 500mL of toluene was added to a dry 1L autoclave under an ethylene atmosphere, and the mixture was stirred for 5 minutes to stabilize the reaction temperature at 70 ℃. Adding 50mmol of methyl acrylate toluene solution, then quickly adding 50 mu mol of complex A-4 toluene solution, immediately introducing 20bar of ethylene gas, and violently stirring for reacting for 60 minutes;

And performing nuclear magnetic analysis, thermal analysis and molecular weight characterization on the product. The test results show that the structures of the products obtained in the examples of the invention are consistent with those of P3 and P4. Wherein the insertion rate of methyl acrylate is 2.5 mol%, the melting temperature of the copolymer is 104 ℃, and the molecular weight is 1.3 multiplied by 10³。

Example 23:

the catalyst used in this example was complex B-1, and the polymer produced was an ethylene/methyl acrylate random copolymer.

The specific steps of the complex B-1 in the embodiment for catalyzing the copolymerization of ethylene and methyl acrylate are as follows:

(1) 500mL of toluene was added to a dry 1L autoclave under an ethylene atmosphere, and the mixture was stirred for 5 minutes to stabilize the reaction temperature at 70 ℃. Adding 100mmol of methyl acrylate toluene solution, then quickly adding 50 mu mol of complex B-1 toluene solution, immediately introducing 20bar of ethylene gas, and violently stirring for reacting for 60 minutes;

And performing nuclear magnetic analysis, thermal analysis and molecular weight characterization on the product. Wherein the DSC curve is shown in figure 7 of the accompanying drawings. The test results show that the structure of the product obtained by the embodiment of the invention is consistent with that of P4. Wherein the insertion rate of methyl acrylate is 6.5 mol%, the melting temperature of the copolymer is 112 deg.C, and the molecular weight is 8.5 × 10³。

Example 24:

the catalyst used in this example was complex C-1, and the polymer produced was an ethylene/methyl acrylate random copolymer.

The specific steps of the complex C-1 in the embodiment for catalyzing the copolymerization of ethylene and methyl acrylate are as follows:

(1) 500mL of toluene was added to a dry 1L autoclave under an ethylene atmosphere, and the mixture was stirred for 5 minutes to stabilize the reaction temperature at 70 ℃. Adding 100mmol of methyl acrylate toluene solution, then quickly adding 50 mu mol of complex C-1 toluene solution, immediately introducing 20bar of ethylene gas, and violently stirring for reacting for 60 minutes;

And performing nuclear magnetic analysis, thermal analysis and molecular weight characterization on the product. The test results show that the structure of the product obtained by the embodiment of the invention is consistent with that of P4. Wherein the insertion rate of methyl acrylate is 2.0 mol%, the melting temperature of the copolymer is 118 ℃, and the molecular weight is 12 multiplied by 10³。

Example 25:

the catalyst used in this example was complex A-1, and the polymer produced was an ethylene/methyl methacrylate random copolymer.

In this example, the specific steps of the complex A-1 catalyzing the copolymerization of ethylene and methyl methacrylate are as follows:

(1) 500mL of toluene was added to a dry 1L autoclave under an ethylene atmosphere, and the mixture was stirred for 5 minutes to stabilize the reaction temperature at 70 ℃. Adding 50mmol of methyl methacrylate in toluene, quickly adding 50 mu mol of complex A-1 in toluene, immediately introducing 20bar of ethylene gas, and violently stirring for reacting for 60 minutes;

(2) after the polymerization reaction is finished, the ethylene gas in the kettle is emptied, and then the reaction liquid in the kettle is poured into 1L of methanol for sedimentation. Then filtering, washing and vacuum drying to obtain the ethylene/methyl methacrylate random copolymer.

And performing nuclear magnetic analysis, thermal analysis and molecular weight characterization on the product. Wherein nuclear magnetism¹H NMR is shown in figure 5. The test results show that the structures of the products obtained in the examples of the invention are consistent with those of P5 and P6. Wherein the insertion rate of methyl methacrylate is 2.7 mol%, the melting temperature of the copolymer is 108 ℃, and the molecular weight is 2.1 multiplied by 10³。

Example 26:

the catalyst used in this example was complex A-2, and the polymer produced was an ethylene/methyl methacrylate random copolymer.

In this example, the specific steps of the complex A-2 catalyzing the copolymerization of ethylene and methyl methacrylate are as follows:

(1) 500mL of toluene was added to a dry 1L autoclave under an ethylene atmosphere, and the mixture was stirred for 5 minutes to stabilize the reaction temperature at 70 ℃. Adding 100mmol of methyl methacrylate in toluene, quickly adding 50 μmol of complex A-2 in toluene, immediately introducing 20bar of ethylene gas, and vigorously stirring for reaction for 60 min;

And performing nuclear magnetic analysis, thermal analysis and molecular weight characterization on the product. The test results show that the structures of the products obtained in the examples of the invention are consistent with those of P5 and P6. Wherein the insertion rate of methyl methacrylate is 4.5 mol%, the melting temperature of the copolymer is 106 ℃, and the molecular weight is 1.2 multiplied by 10³。

The invention discloses and provides a preparation method of a naphthol skeleton phenol-phosphine neutral nickel catalyst and application of the catalyst in preparation of an ethylene/vinyl polar monomer copolymer. The invention has certain improvement and modification space on the basis of the principle. As will be apparent to those skilled in the art. Therefore, such improvements and modifications are intended to be within the scope of the appended claims. It is to be understood that the embodiments described herein are not to be taken as limitations on the invention, but rather as a means for explaining in detail a portion of the basic principles of the invention which are disclosed.

Claims

1. The naphthol skeleton phenol-phosphine neutral nickel catalyst is characterized by having a structural formula as follows:

wherein: the R group is hydrogen, alkane, silane, aromatic hydrocarbon group; ar (Ar)₁The radical being phenyl, cyclohexyl or 2- (C)₆H₅)-C₆H₄；Ar₂The radical being phenyl, cyclohexyl or 2- (C)₆H₅)-C₆H₄。

2. The catalyst of claim 1, wherein R is hydrogen, methyl, t-butyl, trimethylsilyl, phenyl, 3, 5-dimethylphenyl, or 3, 5-bis (trifluoromethyl) phenyl.

3. The catalyst of claim 1 wherein the substituent R, Ar₁And Ar₂The specific structure of (1) comprises one of the following structures:

4. a method for producing the catalyst according to claim 1; characterized in that naphthol-phosphine ligand and metal nickel source are respectively dissolved in good solvent under argon or nitrogen atmosphere, and then ligand solution is dropwise added into metal nickel source solution; and (3) reacting at room temperature for 8-10 h, filtering, removing the solvent in vacuum, and recrystallizing by using a good solvent/poor solvent system to obtain the naphthol-phosphine neutral nickel catalyst.

5. The method of claim 4, wherein the metallic nickel source is nickel dimethyl bipyridine; the good solvent is toluene and diethyl ether.

6. The method according to claim 4, wherein the molar ratio of the metallic nickel source to the ligand is 1.1 to 1.3.

7. The process as claimed in claim 4, wherein the naphthol-phosphine ligand used has the formula:

wherein, when R is not H, the synthesis method of the naphthol-phosphine ligand is that alpha-naphthol, iodide with R substituent and an alkaline substance are simultaneously dissolved in N, N-dimethylformamide under the atmosphere of argon or nitrogen, and the R substituent is introduced into 8-position of the alpha-naphthol through coupling reaction under the catalysis of palladium chloride; then reacting with dihydropyran to obtain a product a with tetrahydropyranyl group; then carry Ar₁And Ar₂Dropwise adding the phosphine salt solution of the substituent group into the solution of the product a, and reacting in an ice-water bath for 4-6 h; obtaining naphthol-phosphine ligand;

when R is hydrogen, directly reacting alpha-naphthol with dihydropyran to obtain a product a with a tetrahydropyrane group; then carry Ar₁And Ar₂Dropwise adding the phosphine salt solution of the substituent group into the solution of the product a, and reacting in an ice-water bath for 4-6 h; obtaining the naphthol-phosphine ligand.

8. The method of claim 7, wherein the basic substance is potassium carbonate or cesium carbonate; the coupling reaction temperature is 115 ℃; the coupling reaction time is 8-12 h.

9. The naphthol skeleton phenol-phosphine neutral nickel complex of claim 1 used for catalyzing ethylene homopolymerization or ethylene/vinyl polar monomer copolymerization.

10. The method for catalyzing the direct coordination copolymerization of ethylene/vinyl polar monomer by using the catalyst of claim 1 comprises the steps of carrying out high-pressure solution polymerization reaction on ethylene, comonomer and the catalyst in an inert solvent; the comonomer is acrylate polar monomer; the molar ratio of the comonomer to the catalyst is (0-1000): 1; the dosage of the catalyst is 5-30 mu mol; the inert solvent is toluene, xylene or decalin; the ethylene pressure during the reaction is 1-30 bar; the polymerization temperature is 30-100 ℃; the required polymerization time is 10-60 min; the precipitant is methanol, ethanol or acetone.