Nickel catalysts containing pyrene ring α-diimine, their preparation methods, and applications

Abstract

This disclosure presents a pyrene-containing compound, a pyrene-containing α-diimine nickel catalyst, its preparation method, and its applications. The catalyst proposed in this disclosure has the structure shown in formula (II), with an imine compound as the aromatic hydrocarbon host, and the introduction of a pyrene ring yields a novel pyrene-fused-ring aromatic hydrocarbon compound. After coordination with a divalent nickel salt, a novel pyrene-containing α-diimine nickel catalyst is obtained. The prepared catalyst has been used in olefin polymerization reactions and exhibits good catalytic activity and thermal stability, and is also suitable for polymerization reaction systems where polar monomers are present.

Description

Technical Field

[0001] This disclosure relates to the fields of catalytic olefin polymerization and synthesis of high molecular weight polyolefin materials, specifically to a nickel catalyst containing a pyrene ring α-diimine, its preparation method, and its application. Background Technology

[0002] Polyolefin materials are abundant in raw materials, inexpensive, easy to process and mold, and possess excellent comprehensive properties, making them one of the largest-volume and most widely used polymer materials. Polyethylene, in particular, is a thermoplastic resin polymerized from ethylene as the main reactant. It exhibits good chemical stability, excellent electrical insulation, and good resistance to low temperatures and non-oxidizing acid corrosion. Since the early 1930s, when low-density polyethylene (LDPE) was obtained through free radical polymerization, polyolefin materials have gradually developed into the largest-volume, most widely used, and inexpensive synthetic polymer materials. The main method for preparing polyethylene is the low-pressure polymerization process, the core of which lies in the selection of the catalyst. In the 1950s, Ziegler and Natta achieved olefin polymerization under mild conditions using coordination polymerization catalysts, thus promoting the vigorous development of the polyolefin industry.

[0003] As a type of coordination polymerization catalyst, transition metal catalysts have received significant attention from both academia and industry alongside the continuous development of the polyolefin industry. Among them, post-transition metal catalysts, represented by nickel and palladium, have been extensively studied in olefin polymerization and copolymerization reactions of olefins with polar monomers due to their low oxygen affinity and high tolerance to polar groups. These catalysts possess unique "chain-walking" characteristics, enabling the preparation of polyethylene with different branched structures and topologies. Different combinations of compounds can have varying effects on their properties. Therefore, the search for novel catalyst structures is of profound significance for applications in the polyolefin industry. Summary of the Invention

[0004] In view of this, in order to solve at least one technical problem mentioned in the related art and other aspects, this disclosure proposes a nickel catalyst containing a pyrene ring α-diimine, its preparation method and application, and designs and synthesizes a catalyst with an aromatic hydrocarbon as the main body and a π-π stacking effect, wherein the pyrene ring adjusts the steric hindrance of the catalyst metal center, thereby optimizing its catalytic performance.

[0005] In one aspect of this disclosure, a pyrene-containing compound with the structure shown in formula (I) is proposed.

[0006]

[0007] R1 to R5 are independently selected from hydrogen, halogen, substituted or unsubstituted C1 to C6 alkyl, substituted or unsubstituted phenyl, and any two adjacent R1 to R5 can form a ring with each other;

[0008] Z and Y are independently selected from hydrogen, C1-C6 alkyl, C1-C6 haloalkyl, substituted or unsubstituted phenyl, and when Z and Y are selected from C1-C6 alkyl, C1-C6 haloalkyl or substituted or unsubstituted phenyl, Z and Y can form a ring;

[0009] When the above-mentioned substituted or unsubstituted groups have substituents, the substituents are selected from C1 to C6 alkyl, phenyl, or halogen.

[0010] According to embodiments of this disclosure, the cyclic structures of Z and Y include substituted or unsubstituted groups of the following: acenaphthenic, phenanthrene, and one of C5-C8 cycloalkyl groups;

[0011] R1 to R5 are independently selected from methyl, ethyl, isopropyl, or diphenylmethyl;

[0012] Z and Y are independently selected from hydrogen and methyl, or form acenaphthene.

[0013] According to embodiments of this disclosure, its structural formula is shown in any one of the following formulas (I-1) to (I-3):

[0014]

[0015] In another aspect of this disclosure, a nickel catalyst containing a pyrene ring α-diimine is proposed, the structure of which is shown in formula (II).

[0016]

[0017] R1 to R5 are independently selected from hydrogen, halogen, substituted or unsubstituted C1 to C6 alkyl, substituted or unsubstituted phenyl, and any two adjacent R1 to R5 can form a ring with each other;

[0018] Z and Y are independently selected from hydrogen, C1-C6 alkyl, C1-C6 haloalkyl, substituted or unsubstituted phenyl, and when Z and Y are selected from C1-C6 alkyl, C1-C6 haloalkyl or substituted or unsubstituted phenyl, Z and Y can form a ring;

[0019] X is selected from one of halogen, C1-C6 alkyl, C2-C6 alkenyl, allyl, and benzyl;

[0020] When the above-mentioned substituted or unsubstituted groups have substituents, the substituents are selected from C1 to C6 alkyl, phenyl, and halogen.

[0021] According to embodiments of this disclosure, the cyclic structure includes substituted or unsubstituted groups of the following: acenaphthenic, phenanthrene, and one of C5-C8 cycloalkyl groups;

[0022] Preferably, Z and Y are independently selected from hydrogen or form acenaphthene;

[0023] Preferably, R1 to R5 are independently selected from methyl, ethyl, isopropyl, and diphenylmethyl;

[0024] Preferably, X is selected from halogens.

[0025] According to embodiments of this disclosure, the structural formula of the pyrene ring α-diimine nickel catalyst is shown in any of the following formulas (II-1) to (II-3):

[0026]

[0027] In another aspect of this disclosure, a method for preparing the above-mentioned catalyst is provided, comprising:

[0028] The unilateral imine compound of formula (A), the aminopyrene compound of formula (B), and the organic acid catalyst were dissolved in an aprotic solvent and refluxed for 24–72 h to obtain the pyrene ring-containing compound of formula (I).

[0029] A pyrene-containing compound was mixed with a nickel salt in a 1:1 molar ratio to obtain a pyrene-containing α-diimine nickel catalyst as shown in formula (II).

[0030]

[0031] Among them, the aprotic solvent includes one of tetrahydrofuran, petroleum ether, toluene, benzene, dichloromethane, tetrachloromethane, diethyl ether, 1,4-dioxane, and 1,2-dichloroethane;

[0032] Nickel salts include one of NiCl2, NiBr2, NiI2, and (DME)NiBr2;

[0033] Organic acid catalysts include one of trifluoroacetic acid, trichloroacetic acid, p-toluenesulfonic acid, and methanesulfonic acid.

[0034] In another aspect of this disclosure, a method for preparing polyethylene using the above-mentioned catalyst is provided, comprising: adding a liquid nickel catalyst containing pyrene ring α-diimine to ethylene in a protective gas atmosphere, and reacting for 0.1 to 20 hours at 0 to 80°C and 0.2 to 3 MPa to obtain polyethylene;

[0035] Preferably, the above method further includes the use of a co-catalyst to assist the reaction, and the co-catalyst may be selected from methylaluminoxane, diethylaluminum chloride, etc.

[0036] According to embodiments of this disclosure, adding a pyrene-containing α-diimine nickel catalyst liquid to ethylene includes dissolving the pyrene-containing α-diimine nickel catalyst and a pyrene-containing fused-ring aromatic hydrocarbon compound in a solvent at a ratio of 1:0.5 to 1:5 to obtain a catalyst mixture liquid, and adding the catalyst mixture liquid to ethylene;

[0037] Preferably, the pyrene fused-ring aromatic hydrocarbon compound includes one of pyrene, benzo[a]pyrene and benzo[a]pyrene.

[0038] In another aspect of this disclosure, a method for preparing a copolymer of low-carbon olefin and undecenoic acid methyl ester using the above-mentioned catalyst is provided, comprising: mixing and dissolving a pyrene-containing α-diimine nickel catalyst with a low-carbon olefin and undecenoic acid methyl ester in a protective gas atmosphere, and reacting the mixture at 20–80°C and 0.2–3 MPa for 0.1–20 hours to obtain a copolymer of low-carbon olefin and undecenoic acid methyl ester; wherein the low-carbon olefin is a C2-C4 olefin.

[0039] According to embodiments of this disclosure, an imine compound is used as the main aromatic hydrocarbon, and a pyrene ring is introduced to obtain a novel pyrene-fused-ring aromatic hydrocarbon compound. After coordination with a divalent nickel salt, a novel pyrene-ring-containing α-diimine nickel catalyst is obtained. The steric hindrance of the nickel metal center in the catalyst is adjusted by the π-π stacking effect of the pyrene ring, thereby improving the catalyst stability, reducing the branching degree during olefin polymerization, and increasing the monomer activity and the molecular weight of the polyolefin product. Attached Figure Description

[0040] Figure 1 This is the 1H NMR spectrum of the pyrene ring-containing compound in Example 1 of this disclosure;

[0041] Figure 2 This is the carbon NMR spectrum of the pyrene ring-containing compound in Example 1 of this disclosure;

[0042] Figure 3 This is an electrospray mass spectrum (ESI-MS) of the pyrene ring-containing compound in Example 1 of this disclosure;

[0043] Figure 4 This is the 1H NMR spectrum of the pyrene ring-containing compound in Example 2 of this disclosure;

[0044] Figure 5 This is the electrospray mass spectrum of the pyrene ring-containing compound in Example 2 of this disclosure;

[0045] Figure 6 This is the 1H NMR spectrum of the pyrene ring-containing compound in Example 3 of this disclosure;

[0046] Figure 7 This is the carbon NMR spectrum of the pyrene ring-containing compound in Example 3 of this disclosure;

[0047] Figure 8 This is the electrospray mass spectrum of the pyrene ring-containing compound in Example 3 of this disclosure;

[0048] Figure 9 This is a matrix-assisted laser desorption / ionization time-of-flight mass spectrum (MALDI-TOF) of the pyrene ring compound in Example 4 of this disclosure;

[0049] Figure 10 This is a matrix-assisted laser desorption / ionization time-of-flight mass spectrum of the pyrene ring-containing compound in Example 5 of this disclosure;

[0050] Figure 11 This is a matrix-assisted laser desorption / ionization time-of-flight mass spectrum of the pyrene ring compound in Example 6 of this disclosure. Detailed Implementation

[0051] 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.

[0052] The endpoints and any values ​​of the ranges disclosed in this disclosure are not limited to the precise ranges or values, and such ranges or values ​​should be understood to include values ​​close to such ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be regarded as specifically disclosed in this disclosure.

[0053] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit this disclosure. The terms “comprising,” “including,” etc., as used herein indicate the presence of the stated features, steps, operations, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, or components.

[0054] All terms used herein (including technical and scientific terms) have the meanings commonly understood by those skilled in the art, unless otherwise defined. It should be noted that the terms used herein are to be interpreted in a manner consistent with the context of this specification, and not in an idealized or overly rigid way.

[0055] The "chain walk" characteristic of post-transition metal catalysts refers to catalytic activation achieved through dynamic displacement of the catalyst along the polymer backbone to the end of the chain. β-H elimination is a mode of chain termination in polymerization reactions, specifically referring to the combination of the metal center of the catalyst with the hydrogen on the β-position carbon of the polymer chain, forming a metal-hydrogen bond and causing the polymer backbone to separate from the catalyst, thereby obtaining the polymer.

[0056] Therefore, using aromatic hydrocarbons as catalyst ligands is beneficial for designing the structure of α-diimine nickel catalysts to obtain various branched and topological structures. Simultaneously, introducing pyrene ring structures with π-π stacking conjugation effects into post-transition metal catalysts can effectively increase the steric hindrance of the catalyst. Increased steric hindrance of the metal catalyst hinders the bonding between β-H and the catalyst's metal bonds, allowing the polymer chain to continue growing, thus increasing the polymer molecular weight. Branching degree is an important parameter affecting the physical properties of polyolefin materials. For α-diimine catalyst systems, its chain-walking characteristics lead to the formation of branched polymers. The mechanism of this process mainly involves the polymer chains that detach after β-H elimination re-inserting into the catalyst's metal center, moving with the catalyst to new polymer chain ends, thus generating branches. Increased catalyst steric hindrance has an hindering effect, so increasing the steric hindrance of the catalyst will reduce the branching degree of the polyolefin material. However, there is no direct relationship between catalyst activity and steric hindrance effect; therefore, extensive searching, synthesis, and testing are needed to explore the structure and performance of catalysts.

[0057] In one aspect of this disclosure, a pyrene-containing compound with the structure shown in formula (I) is proposed.

[0058]

[0059] R1 to R5 are independently selected from hydrogen, halogen, substituted or unsubstituted C1 to C6 alkyl, substituted or unsubstituted phenyl, and any two adjacent R1 to R5 can form a ring with each other;

[0060] Z and Y are independently selected from hydrogen, C1-C6 alkyl, C1-C6 haloalkyl, substituted or unsubstituted phenyl, and when Z and Y are selected from C1-C6 alkyl, C1-C6 haloalkyl or substituted or unsubstituted phenyl, Z and Y can form a ring;

[0061] When the above-mentioned substituted or unsubstituted groups have substituents, the substituents are selected from C1 to C6 alkyl, phenyl, or halogen.

[0062] According to embodiments of this disclosure, the cyclic structures of Z and Y include substituted or unsubstituted groups of the following: acenaphthenic, phenanthrene, and one of C5-C8 cycloalkyl groups;

[0063] R1 to R5 are independently selected from methyl, ethyl, isopropyl, or diphenylmethyl;

[0064] Z and Y are independently selected from hydrogen and methyl, or form acenaphthene.

[0065] According to embodiments of this disclosure, its structural formula is shown in any one of the following formulas (I-1) to (I-3):

[0066]

[0067] In the embodiments of this disclosure, pyrene-containing compounds with structural formulas (I-1) to (I-3) were synthesized and their structures were verified by nuclear magnetic resonance detection and mass spectrometry.

[0068] In another aspect of this disclosure, a nickel catalyst containing a pyrene ring α-diimine is proposed, the structure of which is shown in formula (II).

[0069]

[0070] R1 to R5 are independently selected from hydrogen, halogen, substituted or unsubstituted C1 to C6 alkyl, substituted or unsubstituted phenyl, and any two adjacent R1 to R5 can form a ring with each other;

[0071] Z and Y are independently selected from hydrogen, C1-C6 alkyl, C1-C6 haloalkyl, substituted or unsubstituted phenyl, and when Z and Y are selected from C1-C6 alkyl, C1-C6 haloalkyl or substituted or unsubstituted phenyl, Z and Y can form a ring;

[0072] X is selected from one of halogen, C1-C6 alkyl, C2-C6 alkenyl, allyl, and benzyl;

[0073] When the above-mentioned substituted or unsubstituted groups have substituents, the substituents are selected from C1 to C6 alkyl, phenyl, and halogen.

[0074] According to embodiments of this disclosure, an imine compound is used as the main aromatic hydrocarbon, and a pyrene ring is introduced to obtain a novel pyrene-fused-ring aromatic hydrocarbon compound. After coordination with a divalent nickel salt, a novel pyrene-ring-containing α-diimine nickel catalyst is obtained. The steric hindrance of the nickel metal center in the catalyst is adjusted by the π-π stacking effect of the pyrene ring, thereby improving the catalyst stability, reducing the branching degree during olefin polymerization, and increasing the monomer activity and the molecular weight of the polyolefin product.

[0075] According to embodiments of this disclosure, the cyclic structure includes substituted or unsubstituted groups of the following: acenaphthenic, phenanthrene, and one of C5-C8 cycloalkyl groups;

[0076] Preferably, Z and Y are independently selected from hydrogen or form acenaphthene;

[0077] Preferably, R1 to R5 are independently selected from methyl, ethyl, isopropyl, and diphenylmethyl;

[0078] Preferably, X is selected from halogens.

[0079] According to embodiments of this disclosure, the structural formula of the pyrene ring α-diimine nickel catalyst is shown in any of the following formulas (II-1) to (II-3):

[0080]

[0081] In the embodiments disclosed herein, nickel catalysts containing pyrene ring α-diimine with structural formulas (II-1) to (II-3) were synthesized and their structures were verified by nuclear magnetic resonance detection and mass spectrometry.

[0082] In another aspect of this disclosure, a method for preparing the above-mentioned catalyst is provided, comprising:

[0083] The unilateral imine compound of formula (A), the aminopyrene compound of formula (B), and the organic acid catalyst were dissolved in an aprotic solvent and refluxed for 24–72 h to obtain the pyrene ring-containing compound of formula (I).

[0084] A pyrene-containing compound was mixed with a nickel salt in a 1:1 molar ratio to obtain a pyrene-containing α-diimine nickel catalyst as shown in formula (II).

[0085]

[0086]

[0087] Among them, the aprotic solvent includes one of tetrahydrofuran, petroleum ether, toluene, benzene, dichloromethane, tetrachloromethane, diethyl ether, 1,4-dioxane, and 1,2-dichloroethane;

[0088] Nickel salts include one of NiCl2, NiBr2, NiI2, and (DME)NiBr2;

[0089] Organic acid catalysts include one of trifluoroacetic acid, trichloroacetic acid, p-toluenesulfonic acid, and methanesulfonic acid.

[0090] According to embodiments of this disclosure, the proton solvent will dissociate, affecting the pH of the reaction system.

[0091] In another aspect of this disclosure, a method for preparing polyethylene using the above-mentioned catalyst is provided, comprising: adding a liquid nickel catalyst containing pyrene ring α-diimine to ethylene in a protective gas atmosphere, and reacting for 0.1 to 20 hours at 0 to 80°C and 0.2 to 3 MPa to obtain polyethylene;

[0092] Preferably, the above method further includes the use of a co-catalyst to assist the reaction, and the co-catalyst may be selected from methylaluminoxane, diethylaluminum chloride, etc.

[0093] According to embodiments of this disclosure, adding a pyrene-containing α-diimine nickel catalyst liquid to ethylene includes dissolving the pyrene-containing α-diimine nickel catalyst and a pyrene-containing fused-ring aromatic hydrocarbon compound in a solvent at a ratio of 1:0.5 to 1:5 to obtain a catalyst mixture liquid, and adding the catalyst mixture liquid to ethylene;

[0094] Preferably, the pyrene fused-ring aromatic hydrocarbon compound includes one of pyrene, benzo[a]pyrene and benzo[a]pyrene.

[0095] According to embodiments of this disclosure, the addition of a pyrene polycyclic aromatic hydrocarbon compound in combination with the catalyst in this disclosure can increase the steric hindrance of the catalyst to increase the molecular weight of the polyethylene product, while reducing the degree of branching.

[0096] In another aspect of this disclosure, a method for preparing a copolymer of low-carbon olefin and undecenoic acid methyl ester using the above-mentioned catalyst is provided, comprising: mixing and dissolving a pyrene-containing α-diimine nickel catalyst with a low-carbon olefin and undecenoic acid methyl ester in a protective gas atmosphere, and reacting the mixture at 20–80°C and 0.2–3 MPa for 0.1–20 hours to obtain a copolymer of low-carbon olefin and undecenoic acid methyl ester; wherein the low-carbon olefin is a C2-C4 olefin.

[0097] It should be noted that the described embodiments are merely some, not all, of the embodiments disclosed herein. Other embodiments obtained by those skilled in the art based on the embodiments of this disclosure without inventive effort are all within the scope of protection of this disclosure.

[0098] The following examples illustrate the specific content of this disclosure, providing data on ligand synthesis, metal compound synthesis, and ethylene polymerization or copolymerization methods. The synthesis of complexes and polymerization processes are carried out under anhydrous and oxygen-free conditions. All sensitive substances are stored in glove boxes, all solvents are rigorously dried and dehydrated, and ethylene gas is purified using a dehydration and deoxygenation column. Unless otherwise specified, all compounds are commercially available and used in this disclosure.

[0099] Nuclear magnetic resonance (NMR) analysis was performed using a Bruker 400MHz NMR instrument. Molecular weight and molecular weight distribution were determined by high-temperature gel permeation chromatography (GPC). Mass spectrometry was performed using a Thermo LTQ Orbitrap XL.

[0100] Example 1: Synthesis of Compound I-1

[0101] 5 mmol of the unilateral imine compound as shown in formula (A-1) and 5 mmol of the 1-aminopyrene compound as shown in formula (B-1) were mixed in a 200 mL round-bottom flask. 100 mL of toluene was added, and the mixture was placed in an oil bath at 140 °C for 24 h to separate the water. After the reaction was complete, excess toluene was concentrated under vacuum, and the crude product was separated by column chromatography to obtain the pyrene-containing compound as shown in formula (Ⅰ-1). Compound Ⅰ-1 was a yellow solid (0.89 g, 2 mmol), with a yield of 40%. A neutral alumina column was used for separation (elution buffer EA / PE = 1 / 100).

[0102]

[0103] The specific structure of compound I-1 was verified by NMR detection, and its structural multi-charged molecular ions were detected by electrospray ionization mass spectrometry to identify macromolecular materials.

[0104] Figure 1 This is the 1H NMR spectrum of the pyrene ring-containing compound in Example 1 of this disclosure.

[0105] like Figure 1 As shown, its proton spectrum data is as follows: 1 H NMR (400MHz, CD2Cl2) δ8.26-8.13(m,3H), 8.10-7.94(m,5H), 7.46(d,J=8.0Hz,1H), 7.19(d,J=7. 4Hz, 2H), 7.12 (s, 1H), 2.84-2.71 (m, 2H), 2.22 (d, J = 12.2Hz, 6H), 1.21 (dd, J = 24.8, 6.9Hz, 12H).

[0106] Figure 2 This is the carbon NMR spectrum of the pyrene ring-containing compound in Example 1 of this disclosure.

[0107] like Figure 2 As shown, its carbon spectrum data is as follows: 13 C NMR (101MHz, CD2Cl2) δ: 169.31, 168.35, 146.36, 145.08, 135.18, 131.72, 131.52, 128.22, 127.45, 127.04, 126.31, 126.10, 125.43, 12 5.39,124.99,124.76,123.94,123.11,122.71,120.87,116.46,54.11,53.84,53.57,53.30,53.03,28.49,23.12,22.68,16.47,16.11.

[0108] Figure 3 This is the electrospray mass spectrum of Embodiment 1 of this disclosure.

[0109] like Figure 3 As shown, its electrospray mass spectrometry data are: ESI-MS (m / z): 445.26316 [M+H] + .

[0110] Example 2: Synthesis of Compound I-2

[0111] 5 mmol of the unilateral imine compound as shown in formula (A-2) and 5 mmol of the 1-aminopyrene compound as shown in formula (B-2) were mixed in a 200 mL round-bottom flask. 100 mL of toluene was added, and the mixture was placed in an oil bath at 140 °C for 24 h to separate the water. After the reaction was complete, excess toluene was concentrated under vacuum, and the crude product was separated by column chromatography to obtain the pyrene-containing compound as shown in formula (Ⅰ-2). Compound Ⅰ-2 was an orange-yellow solid (0.98 g, 1.8 mmol), with a yield of approximately 36%. A neutral alumina column was used for separation (elution buffer EA / PE = 1 / 100).

[0112]

[0113] The specific structure of compound I-2 was verified by NMR detection, and its structural multi-charged molecular ions were detected by electrospray ionization mass spectrometry to identify macromolecular materials.

[0114] Figure 4 This is the 1H NMR spectrum of the pyrene ring-containing compound in Example 2 of this disclosure.

[0115] like Figure 4 As shown, its proton spectrum data is as follows: 1 H NMR (400MHz, CD2Cl2) δ8.32(d,J=8.1Hz,1H),8.14(d,J=6.7Hz,2H),8.09(dd,J=8.2, 4.8Hz,2H),8.02(d,J=9.0Hz,2H),7.97-7.92(m,1H),7.84(dd,J=14.8,6.7Hz,2H),7. 41-7.27(m,4H),7.08(t,J=7.8Hz,1H),6.90(d,J=4.3Hz,1H),6.71(d,J=7.4Hz,1H),6 .48(t,J=7.0Hz,1H),3.23-3.05(m,2H),1.31(d,J=6.8Hz,6H),1.06(d,J=6.9Hz,6H).

[0116] Figure 5 This is the electrospray mass spectrum of Embodiment 1 of this disclosure.

[0117] like Figure 5 As shown, its electrospray mass spectrometry data are: ESI-MS (m / z): 541.26320 [M+H] + .

[0118] Example 3: Synthesis of Compound I-3

[0119] 5 mmol of the unilateral imine compound as shown in formula (A-3), 5.5 mmol of anhydrous zinc chloride, and 15 mL of glacial acetic acid were added to a 100 mL round-bottom flask and stirred at 120 °C for 30 min. Then, 5 mmol of the 1-aminopyrene compound as shown in formula (B-1) was added, and the mixture was heated to 140 °C and refluxed for 3 h. After the reaction was complete, excess toluene was concentrated under vacuum, and the crude product was separated by column chromatography to obtain the pyrene-containing compound as shown in formula (I-3). Compound I-3 was a reddish-brown solid (1.6 g, 2.0 mmol), with a yield of 40%. A neutral alumina column was used for separation (elution buffer EA / PE = 1 / 100).

[0120]

[0121] The specific structure of compound I-1 was verified by NMR detection, and its structural multi-charged molecular ions were detected by electrospray ionization mass spectrometry to identify macromolecular materials.

[0122] Figure 6 This is the 1H NMR spectrum of the pyrene ring-containing compound in Example 3 of this disclosure.

[0123] like Figure 6 As shown, its proton spectrum data is as follows: 1 H NMR (400MHz, CD2Cl2) δ8.35 (d, J=8.2Hz, 1H), 8.26-8.16 (m, 4H), 8.10 (t, J= 7.9Hz,2H),8.05-8.00(m,1H),7.83-7.69(m,3H),7.44-7.36(m,4H),7.31(d ,J=7.3Hz,6H),7.13(d,J=7.5Hz,4H),7.02-6.97(m,1H),6.97-6.82(m,7H) ,6.66(dd,J=13.3,6.9Hz,3H),6.39-6.31(m,1H),5.76(s,2H),2.34(s,3H).

[0124] Figure 7 This is the carbon NMR spectrum of the pyrene ring-containing compound in Example 3 of this disclosure.

[0125] like Figure 7 As shown, its carbon spectrum data is as follows: 13C NMR(101MHz,CD2Cl2)δ162.70,161.85,146.63,146.38,143.35,142.48,140.91,132.58,131.99 ,131.74,13167,130.45,130.05,129.90,12965,129.39,129.13,128.92,128.77,128.70,128.4 6,128.40,128.26,127.89,127.79,127.52,127.29,127.07,126.91,126.30,126.13,125.77,125.69,124.92,124.72,123.78,122.95,115.67,54.03,53.76,53.49,53.22,52.95,52.50,21.32.

[0126] Figure 8 This is the electrospray mass spectrum of Embodiment 3 of this disclosure.

[0127] like Figure 8 As shown, its electrospray mass spectrometry data are: ESI-MS (m / z): 803.34088 [M+H] + .

[0128] Example 4: Synthesis of Catalyst II-1

[0129]

[0130] In a glove box, 1 mmol of compound I-1 and 1 mmol of ethylene glycol dimethyl ether nickel bromide were placed in a 100 mL Shrek flask, followed by the addition of 30 mL of anhydrous dichloromethane. The reaction was carried out at room temperature for 12 h. After the reaction was complete, the solvent was removed by vacuum concentration, and the mixture was recrystallized by adding anhydrous n-hexane. The solid was washed three times with n-hexane after filtration to obtain a pyrene-containing catalyst of formula (II-1). Catalyst II-1 was an orange-red solid (0.56 g, 0.85 mmol), with a yield of approximately 85%.

[0131] Figure 9 This is the matrix-assisted laser desorption / ionization time-of-flight mass spectrum of Embodiment 4 of this disclosure.

[0132] like Figure 9 As shown, the MALDI-TOF (m / z) data is: 583.500 [M-Br]. + Elemental analysis: C 32 H 32 Br2N2Ni; C, 57.86; H, 4.95; N, 4.20.

[0133] Example 5: Synthesis of Catalyst II-2

[0134]

[0135] In a glove box, 1 mmol of compound I-2 and 1 mmol of ethylene glycol dimethyl ether nickel bromide were placed in a 100 mL Shrek flask, followed by the addition of 30 mL of anhydrous dichloromethane. The reaction was carried out at room temperature for 12 h. After the reaction was complete, the solvent was removed by vacuum concentration, and the mixture was recrystallized by adding anhydrous n-hexane. The solid was washed three times with n-hexane after filtration to obtain a pyrene-containing catalyst of formula (II-2). Catalyst II-2 was a dark red solid (0.65 g, 0.85 mmol), with a yield of approximately 85%.

[0136] Figure 10 This is the matrix-assisted laser desorption / ionization time-of-flight mass spectrum of Embodiment 5 of this disclosure.

[0137] like Figure 10 As shown, the MALDI-TOF (m / z) data is: 679.272 [M-Br]. + Elemental analysis: C 40 H 32 Br2N2Ni; C, 63.22; H, 4.15; N, 3.75.

[0138] Example 6: Synthesis of Catalyst II-3

[0139]

[0140] In a glove box, 1 mmol of compound I-3 and 1 mmol of ethylene glycol dimethyl ether nickel bromide were placed in a 100 mL Shrek flask, followed by the addition of 30 mL of anhydrous dichloromethane. The reaction was carried out at room temperature for 12 h. After the reaction was complete, the solvent was removed by vacuum concentration, and anhydrous n-hexane was added for recrystallization. The solid was washed three times with n-hexane after filtration to obtain a pyrene-containing catalyst of formula (II-3). Catalyst II-3 was a dark red solid (0.82 g, 0.80 mmol), with a yield of approximately 80%.

[0141] Figure 11 This is a matrix-assisted laser desorption / ionization time-of-flight mass spectrum of Embodiment 6 of this disclosure.

[0142] like Figure 11 As shown, the MALDI-TOF (m / z) data is: 941.163 [M-Br] + Elemental analysis: C 61 H 42 Br2N2Ni; C, 71.81; H, 4.05; N, 2.76.

[0143] Application Example 1

[0144] Ethylene polymerization was carried out using the catalysts prepared in Examples 4-6, and the specific polymerization methods are as follows:

[0145] In a glove box under nitrogen atmosphere, add 28 mL of n-heptane and 0.25 mmol of diethylaluminum chloride to a 350 mL autoclave equipped with a magnetic stirrer, an oil bath heater, and a thermometer. Connect the container to the high-pressure pipeline and evacuate the pipeline. Heat the container to 20°C in a water bath and keep it at that temperature for 10 minutes.

[0146] Using a syringe, inject 2 mL of dichloromethane solution containing 0.5 μmol of the catalyst prepared in Examples 4-6 into the container, close the valve, adjust the ethylene pressure to 8 atm, and react for 10 min.

[0147] Stop the reaction, open the reaction vessel, add ethanol to precipitate the solid, filter under reduced pressure and dry to obtain white polyethylene solid.

[0148] In this application example, under the same conditions, without adding the catalyst prepared in the examples, and using 2 equivalents of pyrene as a control group, it was found that no polyethylene was formed. That is, pyrene alone does not have catalytic activity.

[0149] The results of ethylene polymerization catalyzed by the catalysts prepared in Examples 4-6 are shown in Table 1:

[0150] Table 1. Nickel complexes in Examples 4-6 a ethylene homopolymerization under certain conditions

[0151]

[0152]

[0153] in, a Polymerization conditions: catalyst dosage: 0.5 μmol, diethylaluminum chloride dosage: 500 equivalents, n-heptane dosage: 28 ml, dichloromethane dosage: 2 ml, ethylene partial pressure: 8 bar, reaction time: 10 min;

[0154] b Active units: 10 6 g·(mol Ni) -1 ·h -1 ;

[0155] c The molecular weight and molecular weight polydispersity index were determined by gel permeation chromatography (GPC) using polystyrene as a standard sample and 1,2,4-trichlorobenzene as a solvent at 160 degrees Celsius.

[0156] dBranching degree was determined by proton nuclear magnetic resonance spectroscopy;

[0157] e The melting point was determined by differential scanning calorimetry (DSC).

[0158] f Additional pyrene dosage: 0.5 equivalents

[0159] Added pyrene dosage: 2.0 equivalents.

[0160] In experiments 1-3 listed in Table 1, no additional pyrene fused-ring aromatic hydrocarbons were added to the catalyst; in experiments 4-9, pyrene fused-ring aromatic hydrocarbons were added to the catalyst.

[0161] As shown in Table 1, the addition of pyrene increases the steric hindrance of the catalyst, resulting in a significant increase in the molecular weight of the polyethylene product and a significant decrease in the degree of branching.

[0162] Application Example 2

[0163] The catalysts prepared in Examples 4-6 were used to carry out copolymerization reactions of ethylene with polar monomers. The specific experimental steps and results are shown in Table 2.

[0164] Table 2 shows the nickel complexes in Examples 4-6. a Ethylene copolymerization with polar monomers under certain conditions

[0165]

[0166]

[0167] in: a Polymerization conditions: Catalyst dosage: 10 μmol, diethylaluminum chloride dosage: 1000 equivalents, ethylene polymerization conditions: 0.8 MPa, methyl 10-undecenoate 0.2 mol / L, 20℃, toluene 28 mL, 60 minutes;

[0168] b Active units: 10 5 g / (mol cat.×h);

[0169] c Melting point of the copolymer;

[0170] d The mole fraction of polar monomer units in the copolymer;

[0171] e Number-average molecular weight unit: kg / mol.

[0172] As shown in Table 2, the catalyst prepared in this disclosure can catalyze the copolymerization of ethylene with polar monomers to prepare polar polyolefins under certain conditions. The highest catalyst activity reached is 3.3 × 10⁻⁶. 5 gmol -1 h -1 The melting point of the ethylene copolymer is 105.9–111.1℃, and the highest number-average molecular weight is 14.5 × 10⁻⁶. 3 g / mol.

[0173] 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. A compound containing a pyrene ring, the structure of which is shown in formula (Ⅰ), Equation (I); in, R1 to R5 are independently selected from hydrogen, halogen, substituted or unsubstituted C1 to C6 alkyl, substituted or unsubstituted phenyl, and any two adjacent R1 to R5 can form a ring with each other; Z and Y are independently selected from hydrogen, C1-C6 alkyl, C1-C6 haloalkyl, substituted or unsubstituted phenyl, or Z and Y form an acenaphthene group; When the above-mentioned substituted or unsubstituted groups have substituents, the substituents are selected from C1~C6 alkyl, phenyl, or halogen.

2. The compound according to claim 1, wherein, R1 to R5 are independently selected from methyl, ethyl, isopropyl, or diphenylmethyl.

3. The compound according to claim 1, wherein, Its structural formula is shown in any one of the following formulas (I-1) to (I-3): (I-1)、 (I-2)、 (I-3)。 4. A nickel catalyst containing a pyrene ring α-diimine, the structure of which is shown in formula (II), Formula (II); in, R1 to R5 are independently selected from hydrogen, halogen, substituted or unsubstituted C1 to C6 alkyl, substituted or unsubstituted phenyl, and any two adjacent R1 to R5 can form a ring with each other; Z and Y are independently selected from hydrogen, C1-C6 alkyl, C1-C6 haloalkyl, substituted or unsubstituted phenyl, or Z and Y form an acenaphthene group; X is selected from one of halogen, C1~C6 alkyl, C2~C6 alkenyl, allyl, and benzyl; When the above-mentioned substituted or unsubstituted groups have substituents, the substituents are selected from C1 to C6 alkyl, phenyl, and halogen.

5. The catalyst according to claim 4, wherein, R1 to R5 are independently selected from one of methyl, ethyl, isopropyl, and diphenylmethyl.

6. The catalyst according to claim 4, wherein, X is selected from halogens.

7. The catalyst according to claim 4, wherein, Its structural formula is shown in any one of the following formulas (II-1) to (II-3): （Ⅱ-1）、 （Ⅱ-2）、 （Ⅱ-3）。 8. A method for preparing a catalyst as described in any one of claims 4 to 7, comprising: The unilateral imine compound of formula (A), the aminopyrene compound of formula (B), and the organic acid catalyst were dissolved in an aprotic solvent and refluxed for 24–72 h to obtain the pyrene ring-containing compound of formula (I). The pyrene-containing compound was mixed with a nickel salt in a 1:1 molar ratio to obtain a pyrene-containing α-diimine nickel catalyst of formula (II). (A)、 (B)、 Equation (I), Formula (II); The aprotic solvent includes one of tetrahydrofuran, petroleum ether, toluene, benzene, dichloromethane, tetrachloromethane, diethyl ether, 1,4-dioxane, and 1,2-dichloroethane. The nickel salt includes one of NiCl2, NiBr2, NiI2, and (DME)NiBr2; The organic acid catalyst comprises one of trifluoroacetic acid, trichloroacetic acid, p-toluenesulfonic acid, and methanesulfonic acid.

9. A method for preparing polyethylene using the catalyst as described in any one of claims 4 to 7, comprising: In a protective gas atmosphere, the liquid α-diimine catalyst containing pyrene ring is added to ethylene, and the reaction is carried out at 0-80°C and 0.2-3 MPa for 0.1-20 hours to obtain polyethylene.

10. The method according to claim 9, wherein, The method also includes using diethylaluminum chloride as a co-catalyst.

11. The method according to claim 9, wherein, Adding the pyrene-containing α-diimine nickel catalyst liquid to ethylene includes dissolving the pyrene-containing α-diimine nickel catalyst and the pyrene fused-ring aromatic hydrocarbon compound in a solvent at a ratio of 1:0.5 to 1:5 to obtain a catalyst mixture liquid, and adding the catalyst mixture liquid to ethylene.

12. The method according to claim 11, wherein, The pyrene fused-ring aromatic hydrocarbon compound includes one of pyrene, benzo[a]pyrene, and benzo[a]pyrene.

13. A method for preparing a copolymer of low-carbon olefins and undecenoic acid methyl ester using the catalyst according to any one of claims 4 to 7, comprising: In a protective gas atmosphere, the pyrene-containing α-diimine nickel catalyst is mixed and dissolved with low-carbon olefins and methyl undecenoate, and reacted for 0.1 to 20 hours at 20–80 °C and 0.2–3 MPa to obtain a copolymer of low-carbon olefins and methyl undecenoate. Among them, low-carbon olefins are C2-C4 olefins.

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