Supported catalysts, methods for their preparation and use

Abstract

The present disclosure provides a supported catalyst, comprising: an ionic liquid modified support, wherein the anion or cation of the ionic liquid reacts with the chemical groups on the surface of the support to modify the support, and the cation of the ionic liquid contains atoms capable of providing electrons; and a complex of a post-transition metal coordinated by a diimine-containing ligand or a phosphine sulfonic acid-containing ligand supported on the ionic liquid modified support, wherein the empty orbital provided by the heteroatom N or O in the complex ligand interacts with the electrons provided by the carbon atom in the cation of the ionic liquid, so as to be anchored on the support by the ionic liquid. The present disclosure changes the surface morphology characteristics of the support by the ionic liquid, forms a medium capable of anchoring the metal complex covering the surface of the support; facilitates the active center of the metal complex to insert the comonomer into the ionic liquid medium; thereby improving the activity of the catalyst and the insertion ratio of the polar monomer.

Description

Technical Field

[0001] This disclosure relates to the field of catalyst technology, and in particular to a supported catalyst, its preparation method, and its application. Background Technology

[0002] With the widespread application of polyolefins, the design and development of high-performance catalysts have attracted considerable attention. Currently, research on polyolefins mainly focuses on two aspects: first, homogeneous systems, where polyolefins have well-defined molecular structures, facilitating modification and enabling mechanistic studies; and second, heterogeneous systems, commonly used in industrial polyolefin polymerization. This approach enhances polymerization reactivity, increases polymer molecular weight, and effectively controls product morphology for continuous polymerization while preventing reactor fouling.

[0003] In industrial applications, the polyolefin industry primarily utilizes heterogeneous polymerization systems because they can further enhance polymerization reactivity, increase polymer molecular weight, and effectively control product morphology for continuous polymerization processes, while simultaneously preventing reactor scaling. Currently, there are three main pathways for heterogeneousizing homogeneous olefin polymerization catalysts on solid supports (see...). Figure 1 (As shown): A) Introducing a precatalyst into a support pretreated with a cocatalyst to form ion pairs for the preparation of supported catalysts. This method is simple and widely used, but the solid support pretreated with the cocatalyst results in significant steric hindrance around the active sites, often leading to low activity and low comonomer insertion. B) Directly loading a metal catalyst (activated with a cocatalyst) onto a support to prepare supported catalysts. This method is not suitable for polymerization systems with sensitive active substances, as the catalyst is prone to deactivation. C) Metal complexes can be used to prepare supported catalysts by reacting with an aluminum cocatalyst-pretreated support through specially designed reaction sites (such as hydroxyl groups or amino groups on ligands). The difference between this method and method A is that the metal complex is covalently linked to the supported cocatalyst, but this method requires the design and synthesis of complex ligand structures.

[0004] Besides the aforementioned drawbacks, these commonly used supported catalyst preparation routes also face challenges in the presence of polar comonomers. For example, the catalyst metal center is more easily detached from the support, and the polar monomer is difficult to insert due to steric hindrance. Therefore, developing supported post-transition metal catalysts with highly efficient catalytic copolymerization capabilities for ethylene and polar monomers is particularly important. This is one of the key scientific problems in the field of transition metal polyolefin catalysts, and also a crucial pathway to achieving the industrial application of functionalized polyolefins. Summary of the Invention

[0005] To at least partially address at least one of the aforementioned technical deficiencies, embodiments of this disclosure primarily provide a supported catalyst, its preparation method, and its application. By introducing an ionic liquid into a support, the ionic liquid alters the surface morphology of the support, forming a medium on the support surface that anchors the metal complex catalyst. This prevents direct interaction between the support surface and the metal complex catalyst, reduces the steric hindrance and poisoning effect of the support on the active centers of the metal complex, and facilitates the insertion of comonomers into the active centers of the metal complex in the ionic liquid medium, thereby improving the catalyst's activity and the insertion ratio of polar monomers.

[0006] To achieve the above objectives, as an embodiment of this disclosure, a supported catalyst is provided, comprising: an ionic liquid-modified support, wherein the anion or cation of the ionic liquid reacts with chemical groups on the surface of the support to modify the support, and the cation of the ionic liquid contains an atom capable of donating electrons; and a post-transition metal complex supported on the ionic liquid-modified support, wherein an empty orbital provided by a heteroatom N or O in the complex ligand interacts with an electron provided by a carbon atom in the cation of the ionic liquid, thereby being anchored to the support by the ionic liquid.

[0007] As an embodiment of another aspect of this disclosure, a method for preparing the above-mentioned supported catalyst is provided, comprising: separating an ionic liquid-modified support into an organic solvent under anhydrous and oxygen-free conditions to obtain an organic dispersion; dissolving a transition metal complex coordinated with a diimine ligand or a phosphonic acid ligand into the organic solvent under anhydrous and oxygen-free conditions to obtain an organic solution; and adding the above-mentioned organic solution into the above-mentioned organic dispersion under anhydrous and oxygen-free conditions and reacting for 1 min to 120 min to obtain the above-mentioned supported catalyst.

[0008] As another embodiment of this disclosure, an application of the above-described supported catalyst in the preparation of polyolefins is provided, wherein olefins are polymerized under the action of the above-described supported catalyst to prepare polyolefins.

[0009] The supported catalysts provided in the above embodiments of this disclosure introduce ionic liquids into the support through the reaction of anions or cations of the ionic liquid with chemical groups on the surface of the support, thereby changing the surface morphology of the support and forming a medium covering the support surface that can anchor metal complexes. This prevents direct interaction between the support surface and the metal complexes, reduces the steric hindrance and poisoning effect of the support on the active centers of the metal complexes, and facilitates the insertion of comonomers into the active centers of the metal complexes in the ionic liquid medium, thereby improving the activity of the catalyst and the insertion ratio of polar monomers. Attached Figure Description

[0010] Figure 1 A schematic diagram illustrating the three main pathways for heterogeneous transformation of homogeneous olefin polymerization catalysts;

[0011] Figure 2 A scanning electron microscope image of SiO2 prepared according to an exemplary embodiment of the present disclosure, which was not treated with an ionic liquid in the comparative example;

[0012] Figure 3 A scanning electron microscope image of an ionic liquid support (IL Support 1) prepared according to an exemplary embodiment of the present disclosure;

[0013] Figure 4 FT-IR image of an ionic liquid support (IL Support 1) prepared according to an exemplary embodiment of the present disclosure;

[0014] Figure 5 A scanning electron microscope (SEM-EDS) image of the supported catalyst of formula (I1) prepared according to an exemplary embodiment of this disclosure; and

[0015] Figure 6 Comparison of polymer morphologies prepared by homogeneous diimine-type metal complex A and ionic liquid-modified supported diimine-type metal complex A as catalysts in the polymerization reaction of ethylene under certain conditions. Detailed Implementation

[0016] To make the objectives, technical solutions and advantages of this disclosure clearer, the following detailed description is provided in conjunction with specific embodiments and the accompanying drawings.

[0017] Because the structure and type of support are crucial to improving the performance of supported catalysts, modifying the support structure and introducing supports with novel structures allows the modified supports to form efficient anchors with various types of post-transition metal catalysts, exhibiting characteristics such as high loading rate and high versatility. This makes it easier to prepare a series of novel high-performance supported post-transition metal catalysts with high catalytic activity, and to use these supported post-transition metal catalysts to prepare functionalized polyolefin materials with high molecular weight.

[0018] According to the general inventive concept of one aspect of this disclosure, a supported catalyst is provided, comprising: an ionic liquid-modified support, wherein the anion or cation of the ionic liquid reacts with chemical groups on the surface of the support to modify the support, and the cation of the ionic liquid contains an atom capable of donating electrons; and a post-transition metal complex supported on the ionic liquid-modified support, wherein an empty orbital provided by a heteroatom N or O in the complex ligand interacts with an electron provided by a carbon atom in the cation of the ionic liquid, thereby being anchored to the support by the ionic liquid.

[0019] The supported catalyst provided in this disclosure introduces the ionic liquid into the support by reacting the anions or cations of the ionic liquid with the chemical groups on the surface of the support, thereby changing the surface morphology of the support and forming a medium covering the support surface that can anchor the metal complex. This prevents direct interaction between the support surface and the metal complex, reduces the steric hindrance and poisoning effect of the support on the active center of the metal complex, and facilitates the insertion of comonomers into the active center of the metal complex in the ionic liquid medium, thereby improving the activity of the catalyst and the insertion ratio of polar monomers.

[0020] In some embodiments of this disclosure, the ionic liquid-modified support includes or Any one of the following; wherein, R′ in -OR′ includes any one of hydrogen, substituted or unsubstituted C1-C6 aliphatic hydrocarbon group, fluorine, chlorine, bromine, iodine, nitro, hydroxyl, substituted silyl group, substituted or unsubstituted phenyl group, and a is an integer from 1 to 20, for example, a is 2, 6, 10, 12, 16, 19; -(AlCl n R 3-n R in m includes C1 to C 12 The hydrocarbon group, n is an integer from 0 to 3, for example, n is 1 or 2, m is an integer from 1 to 20, for example, m is 3, 8, 12, 16, or 19; Y includes any one of substituted pyrrolonnium and substituted imidazolium, wherein the substituents of substituted pyrrolonnium and substituted imidazolium include any one of hydrogen, substituted or unsubstituted C1-C6 aliphatic hydrocarbon groups, fluorine, chlorine, bromine, iodine, nitro, hydroxyl, substituted silyl, and substituted or unsubstituted phenyl groups; the support includes any one of silicon dioxide, magnesium oxide, titanium dioxide, zinc oxide, aluminum oxide, magnesium chloride, glass fiber, graphene, expanded graphite, ammonium polyphosphate, and carbon black; the post-transition metal includes any one of nickel and palladium; the ionic liquid includes

[0021] Any one of them.

[0022] In some embodiments of this disclosure, the diimine-containing ligand includes Any one of them; phosphonic acid-containing ligands include Ar includes any one of substituted phenyl or substituted naphthyl groups, wherein the substituents in the substituted phenyl or substituted naphthyl groups include hydrogen, substituted or unsubstituted C1 to C2 groups. 12 Aliphatic hydrocarbon groups, fluorine, chlorine, bromine, iodine, nitro, hydroxyl, substituted silyl groups, substituted or unsubstituted phenyl groups; R1 and R2 include hydrogen, substituted or unsubstituted C1-C2 groups. 12 The aliphatic hydrocarbon group, substituted silyl group, substituted or unsubstituted phenyl group; or R1 and R2 can bond to each other or form a ring; M1 to M5 and N1 to N6 respectively include hydrogen, substituted or unsubstituted C1 to C2 groups. 12 It can be any one of aliphatic hydrocarbon groups, fluorine, chlorine, bromine, iodine, nitro, hydroxyl, substituted silyl groups, or substituted or unsubstituted phenyl groups.

[0023] In some embodiments of this disclosure, the coordination compound includes Any one of the following; X′ and Y′ include fluorine, chlorine, bromine, iodine, C1~C 12 It can be any one of aliphatic hydrocarbon groups, aryl groups, oxygen-containing groups, nitrogen-containing groups, sulfur-containing groups, boron-containing groups, aluminum-containing groups, phosphorus-containing groups, silicon-containing groups, and tin-containing groups; or the X′ and Y′ parts can bond to each other or form a ring; Ar, R1, R2, M1 to M5, N1 to N6 are as defined above.

[0024] In some embodiments of this disclosure, the oxygen-containing group includes any one of alkoxy, sulfone, and carboxyl groups; the nitrogen-containing group includes any one of pyridyl, nitro, cyano, pyrrole, thiazolyl, imidazolyl, pyrazolyl, and pyrimidinyl groups; the sulfur-containing group includes any one of sulfone and thiophene groups; the boron-containing group includes phenylboron; the aluminum-containing group includes any one of alkylaluminum and alkoxyaluminum; the phosphorus-containing group includes any one of phenylphosphine and alkylphosphine; and the silicon-containing group includes siloxy.

[0025] In some embodiments of this disclosure, any one of the structures shown in formulas (I1) to (I6) is included:

[0026]

[0027]

[0028] According to embodiments of this disclosure, a method for preparing the above-mentioned supported catalyst is also provided, comprising: separating an ionic liquid-modified support into an organic solvent under anhydrous and oxygen-free conditions to obtain an organic dispersion; dissolving a complex of a post-transition metal coordinated with a diimine ligand or a phosphonic acid ligand into the organic solvent under anhydrous and oxygen-free conditions to obtain an organic solution; adding the organic solution to the organic dispersion under anhydrous and oxygen-free conditions and reacting for 1 min to 120 min, for example, 26 min, 58 min, 76 min, 96 min, or 118 min; to obtain the supported catalyst.

[0029] In some embodiments of this disclosure, the mass ratio of the complex to the ionic liquid-modified support in the preparation method of the supported catalyst includes 1:20 to 1:50000, for example, 1:50, 1:120, 1:1200, 1:2600, 1:3600, and 1:4800. Within this range, the metal complex can be uniformly loaded onto the ionic liquid-modified support, achieving a high loading capacity.

[0030] In some embodiments of this disclosure, the organic solvent includes one or more of tetrahydrofuran, petroleum ether, toluene, benzene, dichloromethane, tetrachloromethane, 1,4-dioxane, and 1,2-dichloroethane.

[0031] According to embodiments of this disclosure, an application of the above-mentioned supported catalyst in the preparation of polyolefins is also provided, wherein olefins are polymerized under the action of the supported catalyst to prepare polyolefins.

[0032] In some embodiments of this disclosure, the above-described supported catalyst is used in the preparation of polyolefins, wherein the olefins include ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 4-methyl-1-pentene, 1-decene, 1-dodecene, 1-octadecene, and C2-C6 groups containing polar groups. 20 The 1-olefin derivative and the cyclic olefin derivative containing a polar group are both acceptable. The polar group includes any one of the following organic functional groups: oxygen-containing, nitrogen-containing, sulfur-containing, and selenium-containing. The organic functional group includes any one of the following groups: hydroxyl, carboxyl, ester, alkoxy, amino, amide, thioether, silyl ether, and selenyl ether. The oxygen-containing group includes any one of the following groups: alkoxy, sulfone, and carboxyl. The nitrogen-containing group includes any one of the following groups: pyridyl, nitro, cyano, pyrrole, thiazolyl, imidazolyl, pyrazolyl, and pyrimidinyl. The sulfur-containing group includes any one of the following groups: sulfone and thiophene.

[0033] In some embodiments of this disclosure, the polymerization temperature of the above-mentioned supported catalyst in the preparation of polyolefins includes 0°C to 200°C, for example, 36°C, 79°C, 106°C, 156°C, and 189°C; and the polymerization pressure includes 0.1 MPa to 50 MPa, for example, 2.6 MPa, 10.6 MPa, 26.8 MPa, 38.9 MPa, and 46.8 MPa.

[0034] In some embodiments of this disclosure, the polymerization reaction for preparing polyolefins can employ slurry polymerization, loop polymerization, gas-phase polymerization, or other forms of polymerization processes, and is not limited herein.

[0035] In some embodiments of this disclosure, the polymerization reaction for preparing polyolefins is generally carried out in an organic solvent, such as a hydrocarbon, cyclic hydrocarbon, or aromatic organic solvent. To facilitate reactor operation and the polymerization product, in some preferred embodiments, the organic solvent may be a hydrocarbon with fewer than 12 carbon atoms, for example, including but not limited to hexane, toluene, chlorobenzene, and mixtures thereof.

[0036] The present disclosure is further illustrated below by way of comparative examples and embodiments. In the following detailed description, numerous specific details are set forth to provide a comprehensive explanation of embodiments of the present disclosure for ease of explanation. However, it will be apparent that one or more embodiments may be practiced without these specific details. Moreover, the details in the following embodiments may be arbitrarily combined to form other feasible embodiments without conflict.

[0037] In the following examples and comparative examples, the synthesis of catalyst ligands, the synthesis of catalysts, and the polymerization process were all carried out under anhydrous and oxygen-free conditions. All sensitive substances were stored in a glove box, all solvents were rigorously dried to remove moisture, ethylene gas was purified by dehydration and deoxygenation column chromatography, and polar monomers were purified by dehydration, deoxygenation, and vacuum distillation. Unless otherwise specified, all raw materials were used directly after purchase.

[0038] Silica gel column separation was performed using 200–300 mesh silica gel; NMR was performed using a Bruker 400 MHz NMR instrument; elemental analysis was conducted by the Physical and Chemical Research Center of the University of Science and Technology of China; molecular weight and molecular weight distribution were determined by GPC (polystyrene columns, HR2 and HR4, oven temperature 45℃, using Water 1515 and Water 2414 pumps; mobile phase was trichlorobenzene, flow rate 1.0 mL / min, using polydisperse polystyrene as the standard); mass spectrometry was performed using a Thermo LTQ Orbitrap XL (ESI+) or P-SIMS-Gly of Bruker Daltonics Inc (EI+). Metal content was determined by inductively coupled plasma atomic emission spectrometry (ICP) (Prodigy ICP, Lehman Laboratories, USA), wavelength range 165–800 nm, resolution ≤0.005 nm.

[0039] Example 1

[0040] Preparation of ionic liquid support (IL Support) 1:

[0041]

[0042] S1: Under an inert atmosphere, 17.47 g of 1-methyl-3-butylimidazolium chloride and 26.67 g of anhydrous AlCl3 were added to a round-bottom flask and stirred overnight to obtain an ionic liquid;

[0043] S2: The ionic liquid obtained in S1 is added to calcined silica and stirred overnight. Then it is washed with hot dichloromethane to obtain ionic liquid support (IL Support) 1.

[0044] The scanning electron microscope image of the prepared ionic liquid support (IL Support) 1 is shown below. Figure 3 As shown; Figure 4 The FT-IR characterization of the ionic liquid support (IL Support) 1 is shown at 1104 cm⁻¹. -1 804cm -1 473cm -1 This is a Si-O stretching vibration, 1628 cm⁻¹. -1 It is a CN stretching vibration.

[0045] Example 2

[0046] Preparation of ionic liquid support (IL Support) 2

[0047]

[0048] S1: Under an inert atmosphere, add 1-methyl-3-[3-(triethylsiloxane)propyl]imidazolium chloride to calcined silica in a round-bottom flask and stir overnight;

[0049] S2: Add 2 equivalents of aluminum trichloride to the mixed solution obtained in S1 and stir overnight. Then wash with hot dichloromethane to obtain ionic liquid support 2 (IL Support 2).

[0050] Example 3

[0051] Preparation of the supported catalyst shown in formula (I1)

[0052]

[0053] S1: In an inert atmosphere, the diimine-type metal complex... 10 mg dissolved in dichloromethane;

[0054] S2: In an inert atmosphere, add the mixed solution obtained in S1 to a solution containing 1g of IL Support. The supported catalyst was stirred in a dichloromethane solution for 60 min, filtered, washed with the solid, and dried to obtain the supported catalyst shown in formula (I1).

[0055] The scanning electron microscope (SEM-EDS) image of the supported catalyst shown in formula (I1) is as follows: Figure 5 As shown.

[0056] Example 4

[0057] Preparation of the supported catalyst shown in formula (I2)

[0058]

[0059] S1: In an inert atmosphere, the diimine-type metal complex... 10 mg dissolved in dichloromethane;

[0060] S2: In an inert atmosphere, add the mixed solution obtained in S1 to a solution containing 1g of IL Support. The supported catalyst was stirred in a dichloromethane solution for 60 min, filtered, washed with the solid, and dried to obtain the supported catalyst shown in formula (I2).

[0061] Example 5

[0062] Preparation of the supported catalyst shown in formula (I3)

[0063]

[0064] S1: In an inert atmosphere, the diimine-type metal complex C 10 mg dissolved in dichloromethane;

[0065] S2: In an inert atmosphere, add the mixed solution obtained in S1 to a solution containing 1 g of IL Support1. The supported catalyst was stirred in a dichloromethane solution for 60 min, filtered, washed with the solid, and dried to obtain the supported catalyst shown in formula (I3).

[0066] Example 6

[0067] Preparation of the supported catalyst shown in formula (I4)

[0068]

[0069] S1: In an inert atmosphere, diimine-type metal complex A 10 mg dissolved in dichloromethane;

[0070] S2: In an inert atmosphere, add the mixed solution obtained in S1 to a solution containing 1g of IL Support2. The supported catalyst was stirred in a dichloromethane solution for 60 min, filtered, washed with the solid, and dried to obtain the supported catalyst shown in formula (I4).

[0071] Example 7

[0072] Preparation of the supported catalyst shown in formula (I5)

[0073]

[0074] S1: In an inert atmosphere, the diimine-type metal complex B 10 mg dissolved in dichloromethane;

[0075] S2: In an inert atmosphere, add the mixed solution obtained in S1 to a solution containing 1g of IL Support2. The supported catalyst was stirred in a dichloromethane solution for 60 min, filtered, washed with the solid, and dried to obtain the supported catalyst shown in formula (I5).

[0076] Example 8

[0077] Preparation of the supported catalyst shown in formula (I6)

[0078]

[0079] S1: In an inert atmosphere, the diimine-type metal complex C 10 mg dissolved in dichloromethane;

[0080] S2: In an inert atmosphere, add the mixed solution obtained in S1 to a solution containing 1g of IL Support2. The supported catalyst was stirred in a dichloromethane solution for 60 min, filtered, washed with the solid, and dried to obtain the supported catalyst shown in formula (I6).

[0081] Example 9

[0082] Ethylene polymerization was carried out using the supported catalysts prepared in Examples 3-5, diimine-type metal complex A, diimine-type metal complex B, and diimine-type metal complex C, respectively. The specific polymerization methods are as follows:

[0083] S1: In a glove box under a nitrogen atmosphere, add 15 mL of n-heptane to a 350 mL autoclave (equipped with a magnetic stirrer, oil bath heating device and thermometer), then connect the container to the high-pressure pipeline and evacuate the pipeline, and set the container temperature to 30°C and keep it at that temperature for 5 min.

[0084] S2: The supported catalyst (containing 1 μmol of nickel) prepared in Examples 3-5, diimine metal complex A, diimine metal complex B, and diimine metal complex C were dispersed in 5 mL of n-heptane and injected into a high-pressure reactor using a syringe. Then, the required equivalent of diethylaluminum chloride was injected. The ethylene valve was then opened, and ethylene was introduced into the high-pressure reactor. The ethylene pressure was adjusted to 8 atmospheres, and the reaction was allowed to proceed for 10 min. Afterward, the reaction was stopped, the high-pressure reactor was opened, and ethanol was added to precipitate the solid. The mixture was filtered under reduced pressure and dried in a vacuum drying oven to obtain a white solid. The results are shown in Table 1.

[0085] S3: Take pictures of the polymers obtained in serial numbers 2 and 5. The resulting images are shown in... Figure 6 .

[0086] Comparative Example 1

[0087] Ethylene polymerization was carried out using diimine-type metal complex A, diimine-type metal complex B, and diimine-type metal complex C, respectively. The specific polymerization methods are as follows:

[0088] Except for “in step S2, diimine-type metal complex A, diimine-type metal complex B and diimine-type metal complex C are dispersed in 5 mL of n-heptane; in step S3, the polymer obtained by serial number 1 is photographed”, the rest is the same as in Example 9.

[0089] Table 1

[0090]

[0091]

[0092] Remark:

[0093] a Polymerization conditions: 1 μmol catalyst, 20 mL n-heptane, 8 atm ethylene, and 15 min reaction time; b The unit of activity is 10. 6 g·mol -1 ·h -1 ;

[0094] c Melting point was determined using a differential scanning calorimeter.

[0095] d The unit of number-average molecular weight is 10. 4 g mol -1 The molecular weight was determined by GPC using polystyrene as the standard and trichlorobenzene as the solvent at 150°C.

[0096] e Branching degree: The branching degree is determined by 1H NMR spectroscopy.

[0097] Based on the data analysis in Table 1, the following conclusions can be drawn: Compared to catalysts with post-transition metal complexes, catalysts with post-transition metal complexes supported on ionic liquid-modified supports exhibit increased catalyst activity, higher number-average molecular weight, lower molecular weight distribution, and lower branching degree in the polymerization of ethylene under certain conditions. The highest polymerization activity reached 16.8 × 10⁻⁶. 6 g·mol -1 ·h -1 It has a melting point of up to 123.5℃ and a number-average molecular weight distribution ranging from 0.33 to 224.1 × 10⁻⁶. 4 g / mol, with a molecular weight distribution of 1.5–3.9.

[0098] according to Figure 6 The analysis yields the following conclusions: When the polymerization of ethylene is catalyzed under certain conditions, the polymer prepared by the diimine-type metal complex A is amorphous; when the supported catalyst shown in formula (I1) is used as the catalyst, the polymers prepared under different conditions are all semi-crystalline polymers.

[0099] Example 10

[0100] The supported catalysts prepared in Examples 3 and 5 were used for the copolymerization of ethylene with polar monomers. The specific polymerization method is as follows:

[0101] S1: In a glove box under a nitrogen atmosphere, add 15 mL of n-heptane and the required amount of polar monomer to a 350 mL autoclave (equipped with a magnetic stirrer, oil bath heating device and thermometer). Then connect the container to the high-pressure pipeline and evacuate the pipeline. Set the container temperature to 30°C and keep it at that temperature for 5 min.

[0102] S2: The supported catalysts (containing 10 μmol of nickel) prepared in Examples 3 and 5 were dispersed in 5 mL of n-heptane and injected into a high-pressure reactor using a syringe, followed by the required equivalent of diethylaluminum chloride. The ethylene valve was then opened, and ethylene was introduced into the high-pressure reactor. The ethylene pressure was adjusted to 8 atmospheres, and the reaction was allowed to proceed for 10 min. Afterward, the reaction was stopped, the high-pressure reactor was opened, and ethanol was added to precipitate the solid. The mixture was then filtered under reduced pressure and dried in a vacuum drying oven to obtain a white solid. The results are shown in Table 2.

[0103] Table 2

[0104]

[0105] Remark:

[0106] a Polymerization conditions: 10 μmol catalyst, 20 mL n-heptane, 8 atm ethylene, polymerization temperature 30℃, reaction time 30 min;

[0107] b The unit of activity is 10. 5 g·mol -1 ·h -1 ;

[0108] c The polar monomer insertion ratio was determined by proton nuclear magnetic resonance spectroscopy.

[0109] d Melting point was determined using a differential scanning calorimeter.

[0110] e The unit of number-average molecular weight is 10. 4 g mol -1 The molecular weight was determined by GPC using polystyrene as the standard and trichlorobenzene as the solvent at 150°C.

[0111] Based on the data analysis in Table 2, the following conclusions can be drawn: Under certain conditions, the catalysts of post-transition metal complexes supported on ionic liquid-modified supports can achieve a polymerization activity of up to 3.1 × 10⁻⁶. 5 g·mol -1 ·h -1The highest polar monomer insertion ratio can reach 5.1%; the melting point can reach 124.2℃, and the number-average molecular weight distribution is 0.3~4.9×10 4 g / mol, with a molecular weight distribution ranging from 2.1 to 4.4.

[0112] The supported catalysts, their preparation methods, and applications disclosed in this invention introduce ionic liquids into the support through the reaction of the anions or cations of the ionic liquid with chemical groups on the support surface. This alters the surface morphology of the support, forming a medium covering the support surface capable of anchoring metal complexes. This prevents direct interaction between the support surface and the metal complexes, reduces steric hindrance and poisoning effects of the support on the active centers of the metal complexes, and facilitates the insertion of comonomers into the active centers of the metal complexes within the ionic liquid medium. Applying ionic liquid-modified supports to supported post-transition metal catalysts improves catalyst activity, increases polymer thermal stability, melting point, and molecular weight, and prevents scale buildup. In copolymerization, it also enhances the catalyst's resistance to polar monomer poisoning and increases the polar monomer insertion ratio, which is beneficial for the copolymerization of ethylene and polar monomers using supported post-transition catalysts. Furthermore, ionic liquids are inexpensive, widely available, safe, environmentally friendly, easily separated and recovered, and green. Their application in heterogeneous polymerization systems using supported post-transition metal catalysts is beneficial for the industrial application of heterogeneous catalysts in olefin polymerization.

[0113] The specific embodiments described above further illustrate the purpose, technical solutions, and beneficial effects of this disclosure. It should be understood that the above descriptions are merely specific embodiments of this disclosure and are not intended to limit this disclosure. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this disclosure should be included within the protection scope of this disclosure.

Claims

1. The application of a supported catalyst in the preparation of polyolefins, characterized in that, Under the action of the supported catalyst, olefins undergo polymerization to prepare polyolefins; The supported catalyst includes: An ionic liquid-modified support, wherein the ionic liquid's anion or cation reacts with chemical groups on the support surface to modify the support, and the ionic liquid's cation contains atoms capable of donating electrons; and A post-transition metal complex supported on a support modified by the ionic liquid, wherein an empty orbital provided by a heteroatom N or O in the complex ligand interacts with an electron provided by a carbon atom in the cation of the ionic liquid, thereby being anchored to the support by the ionic liquid. The ionic liquid includes ; The carrier includes any one of silicon dioxide, magnesium oxide, titanium dioxide, zinc oxide, aluminum oxide, magnesium chloride, glass fiber, graphene, expanded graphite, ammonium polyphosphate, and carbon black. The post-transition metal includes either nickel or palladium; The diimine-containing ligands include , Any one of them; The phosphonic acid-containing ligands include ; Ar includes any one of substituted phenyl or substituted naphthyl groups, wherein the substituents in the substituted phenyl or substituted naphthyl groups include hydrogen, substituted or unsubstituted C1~C2 groups. 12 Aliphatic hydrocarbon groups, fluorine, chlorine, bromine, iodine, nitro, hydroxyl, substituted silyl groups, substituted or unsubstituted phenyl groups; R1 and R2 include hydrogen, substituted or unsubstituted C1~C. 12 Any one of aliphatic hydrocarbon groups, substituted silyl groups, or substituted or unsubstituted phenyl groups; R1 and R2 can form bonds or rings with each other; M1~M5 and N1~N6 respectively include hydrogen, substituted or unsubstituted C1~C1, etc. 12 It can be any one of aliphatic hydrocarbon groups, fluorine, chlorine, bromine, iodine, nitro, hydroxyl, substituted silyl groups, or substituted or unsubstituted phenyl groups.

2. The application according to claim 1, characterized in that, The complex includes , , , Any one of them; X′ and Y′ include fluorine, chlorine, bromine, iodine, and C1~C64. 12 Any one of the following: aliphatic hydrocarbon group, aryl group, oxygen-containing group, nitrogen-containing group, sulfur-containing group, boron-containing group, aluminum-containing group, phosphorus-containing group, silicon-containing group, and tin-containing group; The X′ and Y′ parts can form bonds or rings with each other; Ar, R1, R2, M1~M5, N1~N6 are defined as in claim 1.

3. The application according to claim 2, characterized in that, The oxygen-containing group includes any one of alkoxy, sulfone, and carboxyl groups; The nitrogen-containing group includes any one of pyridyl, nitro, cyano, pyrrole, thiazolyl, imidazolyl, pyrazolyl, and pyrimidinyl. The sulfur-containing group includes any one of sulfone group and thiophene group; The boron-containing group includes a phenylboron group; The aluminum-containing group includes any one of alkylaluminum group and alkoxyaluminum group; The phosphorus-containing group includes phenylphosphine alkyl; The silicon-containing group includes siloxy groups.

4. The application according to claim 1, characterized in that, The supported catalyst includes any one of the structures shown in formulas (I4) to (I6): Equation (I4) Equation (I5) Equation (I6).

5. The application according to claim 1, characterized in that, The supported catalyst was obtained through the following method: Under anhydrous and oxygen-free conditions, the ionic liquid-modified support is dispersed in an organic solvent to obtain an organic dispersion. Under anhydrous and oxygen-free conditions, a transition metal complex coordinated with a ligand containing a diimine or a ligand containing phosphonic acid is dissolved in an organic solvent to obtain an organic solution. Under anhydrous and oxygen-free conditions, the organic solution is added to the organic dispersion and reacted for 1 min to 120 min to obtain the supported catalyst.

6. The application according to claim 1, characterized in that, The mass ratio of the complex to the ionic liquid-modified carrier is 1:20 to 1:50000.

7. The application according to claim 1, characterized in that, The olefins include ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 4-methyl-1-pentene, 1-decene, 1-dodecene, 1-octadecene, and C2~C6 groups containing polar groups. 20 Any one of 1-olefins and cycloolefins containing polar groups; The polar group includes any one of the organic functional groups containing oxygen, nitrogen, sulfur, and selenium, and the organic functional group includes any one of the organic functional groups containing hydroxyl, carboxyl, ester, alkoxy, amino, amide, thioether, silyl ether, and selenyl ether.

Images