Fully flexible alpha-diimine catalyst and catalytic application thereof

Abstract

The invention discloses a full-flexible alpha-diimine catalyst and a catalytic application thereof. According to the invention, 1, 2-cyclohexanedione is taken as a core skeleton, and a flexible and large-steric-hindrance naphthenic imine group is ingeniously grafted on the core skeleton, so that the innovative design greatly improves the efficiency of a catalytic system and promotes the generation of polyethylene with higher branching degree and higher molecular weight. The prepared polyethylene material is expected to become a new favorite of high-performance thermoplastic elastomers by virtue of excellent mechanical properties and excellent elastic recovery capability. In a palladium-catalyzed ethylene polymerization reaction, the full-flexible palladium catalyst shows moderate catalytic activity, and a generated polyethylene product is high in branch density, and the molecular weight is also remarkably improved. More noticeably, under the copolymerization experiment condition, the efficient doping of the polar monomer methyl acrylate is successfully realized, the copolymer with considerable polar monomer content is prepared, and a new path is opened up for the modification and functionalization of the polyethylene material.

Description

Technical Field

[0001] The invention belongs to the field of catalysis and olefin polymerization, and specifically relates to a fully flexible alpha-diimine catalyst and catalytic application thereof. Background Art

[0002] Axial shielding plays a crucial role in late transition metal-catalyzed ethylene polymerization. This effect is mainly due to its inhibition of β-H elimination reactions and subsequent chain transfer. Since the development of the Brookhart system in the mid-1990s, various axial shielding substituents have been widely used in late transition metal α-diimine catalytic systems.

[0003] These axial shielding substituents can be roughly divided into two categories according to their conformational flexibility: rigid substituents and flexible substituents. Among them, representative rigid α-diimine catalysts include o-arylaryl catalysts, o-aryldimethyl catalysts, and 8-arylnaphthyl catalysts. These catalysts can effectively inhibit chain transfer reactions during polymerization, thereby producing high molecular weight or even ultra-high molecular weight polyethylene. At the same time, the different orientations of these rigid aromatic groups have a significant effect on the branching density of the resulting polyethylene. Compared with rigid substituents, the introduction of flexible alkyl or cycloalkyl groups at the axial position of the catalytic center can create a dynamically variable stereo environment. This flexibility can effectively promote the coordination and insertion reactions of ethylene in most cases, thereby enhancing the catalytic activity. In addition, the spatial environment near the catalytic center is also conducive to the formation of chain walking and branches. In recent years, large sterically hindered rigid skeletons have often been incorporated into the design of α-diimine catalysts, among which the dibenzobarrelene skeleton is particularly famous. This axial stereo skeleton works synergistically with the axial substituents to promote the realization of active polymerization and even high-temperature active polymerization in many catalytic systems. In addition to the common characteristics of living polymerization, these catalysts can also synthesize ultra-high branched polyethylene with monomethyl branches. However, these classical and rigid catalysts have shortcomings such as poor solubility, easy deposition and clogging of pipelines in industrial production, and limited catalytic activity. These limitations restrict their use in certain industrial scale-up applications, especially when efficient large-scale production is required.

[0004] In view of the poor solubility of classical skeleton and rigid skeleton catalysts in alkane solvents and the frequent reliance on toluene as a reaction solvent, the innovatively designed fully flexible catalyst of the present invention shows significant advantages in commonly used industrial alkane polymerization solvents. The catalyst achieves efficient dispersion in commonly used industrial alkanes by introducing a large number of solubilizing cycloalkyl substituents, effectively avoiding production problems such as catalyst deposition and pipeline blockage. In addition, its fully flexible substituent structure not only enhances the adaptability of the catalyst, but also significantly improves the activity of ethylene polymerization, bringing higher efficiency and benefits to industrial production. Summary of the invention

[0005] In view of the above-mentioned deficiencies in the prior art, the present invention provides an α-diimine catalyst having a flexible cyclohexyl skeleton and an axially flexible cycloalkyl substituent, and uses the catalyst to catalyze olefin polymerization.

[0006] The α-diimine catalyst of the present invention has a flexible cyclohexyl skeleton and an axially flexible cycloalkyl substituent, and its general structural formula is as follows:

[0007] .

[0008] R = cyclopentyl (Cp) or cyclohexyl (Ch), etc.;

[0009] M = Ni, X = Y = Br; alternatively, M = Pd, X = Cl, Y = Me.

[0010] The α-diimine catalyst is preferably:

[0011] Ni1: R = Cp, X = Y = Br;

[0012] Ni2: R = Ch, X = Y = Br;

[0013] Pd1: R = Cp, X = Cl, Y = Me;

[0014] Pd2: R = Ch, X = Cl, Y = Me.

[0015]

[0016] The method for preparing an α-diimine catalyst having a flexible cyclohexyl skeleton and an axially flexible cycloalkyl substituent of the present invention comprises the following steps:

[0017] Step 1: Preparation of ligand

[0018] A methanol solution (5 mL) containing 3 mmol of tricycloalkyl aromatic amine (A1 or A2) was added to 1.4 mmol of 1,2-cyclohexanedione, and a few drops of acetic acid were added as a catalyst. The reaction was stirred at room temperature for two days. After the reaction, the precipitate was separated by filtration, washed with methanol (3 × 2 mL), and vacuum dried to obtain ligand L1 or L2. It was directly used for the preparation of subsequent catalysts without further purification.

[0019] In step 1, the molar ratio of 1,2-cyclohexanedione to tricycloalkyl aromatic amine is 1:2.0-2.5.

[0020] Step 2: Preparation of catalyst

[0021] 2a. Under nitrogen atmosphere, a mixture containing 0.2 mmol of ligand and an equimolar amount of (DME) NiBr2 was dissolved in 10 mL of dichloromethane and stirred at room temperature for 8-12 h until the color of the solution was significantly deepened. After the reaction was completed, the solvent was partially evaporated and the remaining mixture was diluted with 20 mL of anhydrous ether to precipitate an orange-red solid. The solid was separated by filtration, strictly washed with ether, and vacuum dried to obtain the target product Ni1 or Ni2 compound.

[0022] 2b. Under nitrogen atmosphere, a mixture containing 0.4 mmol of ligand and an equimolar amount of (COD) PdMeCl was dissolved in 10 mL of dichloromethane and stirred at room temperature for 8-12 h. After the reaction was completed, part of the solvent was removed and the remaining mixture was diluted with 20 mL of ether to obtain an orange-red solid precipitate. The solid was filtered, rinsed with ether and vacuum dried to obtain the target product Pd1 or Pd2 compound.

[0023] The synthetic route is as follows:

[0024]

[0025] The invention discloses an application of an alpha-diimine catalyst having a flexible cyclohexyl skeleton and an axially flexible cycloalkyl substituent in catalyzing olefin polymerization reaction.

[0026] The olefin is preferably ethylene.

[0027] The polymerization reaction is carried out in a composite catalytic system formed by a catalyst and a co-catalyst, wherein the co-catalyst is Et2AlCl or NaBArF.

[0028] Further, in the process of catalytic ethylene homopolymerization:

[0029] The catalyst is Ni1 or Ni2, the cocatalyst is Et2AlCl, the molar ratio of the catalyst to the cocatalyst Et2AlCl is 1:200 to 1:1000, the amount of the catalyst is 1 to 10 micromoles, the temperature of the ethylene polymerization reaction is controlled between 30°C and 90°C, the ethylene polymerization pressure is maintained at 6 to 30 atmospheres, 40 mL to 100 mL of cyclohexane is used as a solvent, and the reaction time lasts for 30-60 minutes.

[0030] The catalyst is Pd1 or Pd2, and the co-catalyst is NaBArF. The molar ratio of the catalyst to NaBArF is in the range of 1:1 to 1:3, and the amount of the catalyst is 2 to 10 micromoles; the temperature of the ethylene polymerization reaction is controlled between 30°C and 70°C, the ethylene pressure is maintained at 6 to 10 atmospheres, 40 mL to 100 mL of dichloromethane is used as a solvent, and the reaction time lasts for 60-120 minutes.

[0031] Further, in the process of catalyzing the copolymerization of ethylene and acrylic acid ester monomers:

[0032] The catalyst is Pd1 or Pd2, and the co-catalyst is NaBArF. The molar ratio of the catalyst to the co-catalyst NaBArF is in the range of 1:1 to 1:3, the amount of the catalyst is 10 to 20 micromoles, and the concentration of the acrylic ester monomer is 1 to 2 mol / L; the reaction temperature is controlled between 30 and 70°C, the ethylene pressure is maintained at 2 to 10 atmospheres, 20 mL to 100 mL of dichloromethane is used as a solvent, and the reaction time lasts for 3 to 12 hours.

[0033] The acrylic acid ester monomer is preferably methyl acrylate.

[0034] The fully flexible α-diimine nickel catalyst with a skeleton and axial cycloalkyl substituents of the present invention exhibits high efficiency in ethylene homopolymerization (10 6 g·mol -1 ·h -1 ), which can produce polyethylene materials with high molecular weight (up to 1022 kg / mol) and high branching density (up to 103 / 1000C). These polyethylenes have high branching density and low melting point, showing the characteristics of polyolefin elastomers. Tensile tests showed that these polyethylenes exhibited low tensile strength (2.1-7.0MPa) and high fracture strain (592-2248%) at break. In addition, hysteresis tests showed that these materials have good elastic recovery ability, making them high-performance thermoplastic elastomers. Interestingly, the flexible nickel catalyst reported in this study showed higher polymerization activity and produced high molecular weight polyethylene products compared to the nickel catalysts with classic and rigid skeletons reported.

[0035] At the same time, the fully flexible α-diimine palladium catalyst of the present invention exhibits moderate polymerization activity (10 5 g·mol -1 ·h -1 ), and produce polyethylene with high molecular weight (56-203 kg / mol) and high branch density (87-99 / 1000C). Due to the strong tolerance of palladium catalysts to polar groups, we applied them to the copolymerization of ethylene and methyl acrylate (E-MA). These catalysts have low copolymerization activity (10 3 g·mol -1 ·h -1 ), and can produce E-MA copolymers with high branching (96-120 / 1000C) and medium molecular weight (16-40 kg / mol), in which the MA incorporation rate is 1.53-4.54 mol%. Although the copolymerization activity decreases and the molecular weight of the obtained copolymer also decreases, the branching density remains relatively stable.

[0036] The present invention uses 1,2-cyclohexanedione as the core skeleton, and cleverly grafts a flexible and sterically hindered cycloalkylimine group onto it. This innovative design greatly improves the efficiency of the catalytic system and promotes the production of polyethylene with a higher degree of branching and a higher molecular weight. The polyethylene material obtained is expected to become a new favorite of high-performance thermoplastic elastomers due to its excellent mechanical properties and excellent elastic recovery ability. In the palladium-catalyzed ethylene polymerization reaction, this type of fully flexible palladium catalyst exhibits moderate catalytic activity, and the polyethylene product produced not only has a high branching density, but also a significantly improved molecular weight. What is more striking is that under the copolymerization experimental conditions, the present invention successfully achieved the efficient incorporation of the polar monomer methyl acrylate (MA), and produced a copolymer with a considerable polar monomer content, opening up a new path for the modification and functionalization of polyethylene materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 The yield (a), molecular weight (b) and branch density (c) of polyethylene prepared by the catalysts of Examples 1 and 2 at 30°C-90°C. Figure 1 It can be seen that in the presence of 200 equivalents of co-catalyst, both flexible nickel catalysts exhibited extremely high polymerization activity, and the activity changes were minimal at different temperatures, showing good thermal stability. In addition, under the explored conditions, these catalysts efficiently produced polyethylene materials with high molecular weight (up to 1022 kg / mol) and high branching density (up to 103 / 1000C). The molecular weight of the resulting polyethylene decreases with increasing temperature, while the branching density increases accordingly. Regarding the effect of the size of the axial cycloalkyl ring on the polymerization results, the cyclohexyl catalyst with a larger ring has a slightly lower polymerization activity than the cyclopentyl catalyst, but the resulting polyethylene has a higher molecular weight and a higher branching density.

[0038] Figure 2 The activity, molecular weight and branching density of the catalyst of Example 2 are compared with those of the reported nickel catalysts with classical and rigid skeletons for ethylene polymerization under similar conditions. Figure 2 It can be seen that compared with the classic butyl nickel catalyst BD-Ni, the Ni2 catalyst with a flexible cyclohexyl skeleton produced polyethylene with significantly higher molecular weight and slightly higher branching density under similar conditions, while showing higher catalytic activity. In addition, compared with the dibenzo-barrel-ene nickel catalyst DB-Ni, Ni2 produced polyethylene with similar molecular weight under the same conditions, but with significantly lower branching density and significantly higher activity. These results show that the flexibility of the skeleton combined with the adaptability of the axial cyclohexyl shield can effectively inhibit chain transfer and promote chain growth during nickel-catalyzed ethylene polymerization.

[0039] Figure 3The stress-strain curves of polyethylene produced by catalyst (a) of Example 1 and catalyst (b) of Example 2 at 30-90°C are shown in FIG. Figure 3 It can be seen that the obtained polyethylenes exhibit lower tensile strength at break (2.1-7.0 MPa) and higher elongation at break (592%-2248%), and with the increase of production temperature, the tensile strength gradually decreases and the elongation at break gradually increases.

[0040] Figure 4 The hysteresis test graphs of polyethylene produced by catalyst (ad) of Example 1 and catalyst (eh) of Example 2 at 30°C-90°C and 10 cycles under 300% strain are shown in FIG. Figure 4 It can be seen that these materials have good elastic recovery. It is worth noting that the strain recovery (SR) value does not always increase with increasing temperature; it reaches a peak at 50°C (for Ni1) or 70°C (for Ni2) and then starts to decrease.

[0041] Figure 5 The yield (a), molecular weight (b) and branch density (c) of polyethylene prepared by the catalysts of Examples 3 and 4 at 30°C-70°C. Figure 4 As can be seen in the data, these palladium complexes exhibit moderate polymerization activity and produce polyethylene with high molecular weight (56-203 kg / mol) and high branching density (87-99 / 1000C). In most cases, as the temperature increases, the polymerization activity and the molecular weight of the resulting polyethylene both decrease, while the branching density of the resulting polyethylene remains relatively stable. The size of the axial cycloalkyl group also plays a key role in palladium-catalyzed ethylene polymerization, among which cyclohexyl palladium catalysts have low polymerization activity and produce polyethylene with higher molecular weight and lower branching density.

[0042] Figure 6 The yield (a), MA insertion ratio (b), molecular weight (c) and degree of branching (d) of ethylene and MA copolymers prepared by the catalysts of Examples 3 to 4 at 30°C. Figure 6 It can be seen that these catalysts exhibit low copolymerization activity and produce ethylene-methyl acrylate (E-MA) copolymers with medium molecular weight (16-40 kg / mol) and high branching (96120 / 1000C), in which the MA incorporation ratio is between 1.53% and 4.54% mol. As the concentration of comonomer MA increases, the copolymerization activity decreases, the molecular weight of the resulting copolymer also decreases, while the branching density remains relatively stable.

[0043] Figure 7 The detailed carbon spectrum of the copolymer of ethylene and MA prepared by the catalyst of Example 4 at 30°C and 1M MA concentration is as follows. Figure 7 It can be seen that these ethylene-methyl acrylate (E-MA) copolymers contain various types of branched structures, mainly long-chain branches, and polar groups are located at the ends of these long-chain branches. DETAILED DESCRIPTION

[0044] In order to better understand the technical solution of the present invention, the present invention will be further described in detail in conjunction with the examples below. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, rather than limiting the claims of the present invention. Reagents and raw materials used in the examples: All metal organic reactions were carried out under nitrogen protection, and all solvents were dried and deoxygenated. Ethanol was analytically pure and used directly.

[0045] Embodiment 1:

[0046] 1. Synthesis of fully flexible catalyst ligand L1

[0047] A methanol solution (5 mL) containing 3 mmol of 2,4,6-tricyclopentyl-1-phenylamine was added to 1.4 mmol of 1,2-cyclohexanedione, followed by a few drops of acetic acid. The resulting mixture was then stirred at room temperature for two days. Subsequently, the precipitate was isolated by filtration and washed with methanol (3 × 2 mL). Ligand L1 was dried under vacuum and used directly in the subsequent step without further purification in 75% yield.

[0048] The preparation reaction is as follows:

[0049]

[0050] NMR analysis: 1 H NMR (400 MHz, CDCl3) δ 7.03 (d, J = 10.7 Hz, 4H, Ar-H), 6.32 (s, 1H, -CH=C-), 4.77 (s, 1H, -NH-), 3.24 (p, J = 8.5 Hz, 2H, -CH-), 3.06-2.73 (m, 4H, -CH-), 2.28-1.93 (m, 13H, -CH2-), 1.91-1.35 (m, 41H, -CH2-). 13C NMR (101 MHz, CDCl3) δ 162.35 (C=N), 145.43, 144.71, 143.95, 139.24,135.81, 133.76, 130.14, 122.77, 122.31, 122.23, 104.72 (C=C-CH2-), 46.34 (-CH-), 46.31 (-CH-), 46.18 (-CH-), 46.06 (-CH-), 40.93 (-CH-), 40.54 (-CH-), 35.24 (-CH2-), 35.04 (-CH2-), 34.94 (-CH2-), 34.88 (-CH2-), 33.79 (-CH2-),32.52 (-CH2-), 29.59 (-CH2-), 26.07 (-CH2-), 25.92 (-CH2-), 25.87 (-CH2-),25.65 (-CH2-), 25.62 (-CH2-), 25.56 (-CH2-), 25.35 (-CH2-), 24.35 (-CH2-), 23.66 (-CH2-).

[0051] Mass spectrometry: APCI-MS (m / z): calcd for C 48 H 67 N2 + : 671.5299, Found, 671.5268,[M+H] + .

[0052] 2. Synthesis of Ni1 complex

[0053] Under a nitrogen atmosphere, a mixture containing 0.2 mmol of ligand and an equal amount of (DME) NiBr2 was introduced into 10 mL of dichloromethane. This mixture was then stirred at room temperature overnight, resulting in a significant deepening of the color of the solution. After the reaction was complete, the solvent was partially evaporated under reduced pressure. The remaining mixture was then diluted with 20 mL of anhydrous ether, prompting the precipitation of an orange-red solid. The solid was then isolated by filtration, washed rigorously with diethyl ether, and finally dried under vacuum to obtain the target Ni1 compound in 88% yield.

[0054] The preparation reaction is as follows:

[0055]

[0056] Mass spectrometry: MALDI-TOF-MS (m / z): calcd for C 48 H 66BrN2Ni: 807.3757, Found,807.3768, [M-Br] + .

[0057] Embodiment 2:

[0058] 1. Synthesis of fully flexible catalyst ligand L2

[0059] The 2,4,6-tricyclopentyl-1-aniline in step 1 of example 1 was replaced by 2,4,6-tricyclohexyl-1-aniline, and the remaining operations were the same as step 1 of example 1, with a yield of 60%.

[0060] NMR analysis: 1 H NMR (400 MHz, CDCl3) δ 6.96 (d, J = 14.7 Hz, 4H, Ar-H), 6.15 (s, 1H, -CH=C-), 4.68 (d, J = 4.7 Hz, 1H, -NH-), 2.84 (t, J = 11.4 Hz,2H, -CH-), 2.46 (t, J = 12.0 Hz, 4H, -CH-), 2.19 (q, J = 7.1, 5.7 Hz, 4H, -CH2-), 1.79 (dtd, J = 53.0, 26.3, 25.7, 10.8 Hz, 32H, -CH2-), 1.36 (ddd, J =45.1, 21.6, 10.8 Hz, 30H , -CH2-). 13C NMR (101 MHz, CDCl3) δ 162.81 (C=N),145.78, 145.43, 143.54, 143.52, 142.48, 139.41, 135.30, 135.25, 133.69,133.62, 122.54, 122.02, 104.45 (C=C-CH2-), 44.65 (-CH-), 44.47 (-CH-), 39.12(-CH-), 39.02 (-CH-), 34.80 (-CH2-), 34.77 (-CH2-), 34.63 (-CH2-), 34.22 (-CH2-), 34.18 (-CH2-), 33.77 (-CH2-), 29.77 (-CH2-), 27.44 (-CH2-), 27.39 (-CH2-), 27.34 (-CH2-), 27.30 (-CH2-), 27.26 (-CH2-), 27.21 (-CH2-), 27.15 (-CH2-), 27.11 (-CH2-), 27.07 (-CH2-), 27.02 (-CH2-), 26.39 (-CH2-), 26.38 (-CH2-), 26.32 (-CH2-), 26.29 (-CH2-), 24.40 (-CH2-), 24.39 (-CH2-), 24.36 (-CH2-), 23.67 (-CH2-), 23.64 (-CH2-).

[0061] Mass spectrometry: APCI-MS (m / z): calcd for C 54 H 79 N2 + : 755.6238, Found, 755.6237,[M+H] + .

[0062] 2. Synthesis of Ni2 complex

[0063] L1 in step 2 of Example 1 was replaced by L2, and the remaining operations were the same as step (2) of Example 1, with a yield of 90%.

[0064] Mass spectrometry: MALDI-TOF-MS (m / z): calcd for C 54 H 78 BrN2Ni: 891.4696, Found,891.4679, [M-Br] + .

[0065] Example 3: Synthesis of Pd1 complex

[0066] A mixture containing 0.4 mmol of ligand L1 and an equal amount of (COD) PdMeCl was introduced into 10 mL of dichloromethane. The resulting solution was stirred at room temperature overnight, during which its color increased. After the reaction was completed, part of the solvent was removed under reduced pressure, and the remaining mixture was diluted with 20 mL of ether to obtain an orange-red solid precipitate. Subsequently, the solid was filtered, rinsed with ether, and vacuum dried to obtain the target product Pd1. The yield was 75%. The preparation reaction formula is as follows:

[0067]

[0068] NMR analysis: 1 H NMR (400 MHz, CDCl3) δ 7.07 (d, J = 15.2 Hz, 4H, Ar-H), 3.03 (dp, J = 48.3, 8.6 Hz, 6H, -CH-), 2.43 (p, J = 5.6 Hz, 2H, -CH2-), 2.24(dt, J = 25.3, 6.1 Hz, 6H, -CH2-), 2.14-1.97 (m, 5H, -CH2-), 1.91-1.50 (m,43H, -CH2-), 0.53 (s, 3H, Pd-CH3). 13C NMR (101 MHz, CDCl3) δ 175.13 (C=N),170.42 (C=N), 145.32, 144.06, 141.13, 140.56, 135.64, 134.47, 123.69, 122.90,122.42, 45.96 (-CH-), 45.93 (-CH-), 45.80 (-CH-), 41.30 (-CH-), 40.55 (-CH-), 40.52 (-CH-), 35.58 (-CH2-), 34.72 (-CH2-), 34.64 (-CH2-), 34.60 (-CH2-)),34.43 (-CH2-), 34.39 (-CH2-), 34.29 (-CH2-), 34.08 (-CH2-), 33.89 (-CH2-),33.80 (-CH2-), 33.39 (-CH2-), 33.34 (-CH2-), 32.31 (-CH2-), 32.20 (-CH2-),32.03 25.48 (-CH2-), 25.44(-CH2-), 23.87 (-CH2-), 21.60 (-CH2-), 21.57 (-CH2-), 2.76 (Pd-CH3).

[0069] Mass spectrometry: MALDI-TOF-MS (m / z): calcd for C 48 H 66 N2Pd: 776.4255, Found,776.4285, [M-Cl-Me] + .

[0070] Example 4: Synthesis of Pd2 complex

[0071] L1 in step 1 of Example 3 was replaced by L2, and the remaining operations were the same as step (1) of Example 3, with a yield of 60%.

[0072] NMR analysis: 11H NMR (400 MHz, CDCl3) δ 7.01 (d, J = 16.4 Hz, 4H, Ar-H), 2.47 (d, J = 24.4 Hz, 6H, -CH-), 2.27 (d, J = 9.7 Hz, 4H, -CH2-), 1.85 (s, 20H, -CH2-), 1.58 (d, J = 32.0 Hz, 32H, -CH2-), 1.42 (d, J = 10.0 Hz, 12H, -CH2-), 0.52 (s, 3H, Pd-CH3). 13 13C NMR (101 MHz, CDCl3) δ 175.32 (C=N), 170.61 (C=N), 148.09, 137.36, 136.95, 136.23, 123.10, 122.86, 122.46, 44.42 (-CH-), 44.37 (-CH-), 43.35 (-CH-), 40.37 (-CH-), 39.85 (-CH-), 39.25 (-CH-), 34.86 (-CH2-), 34.75 (-CH2-), 34.53 (-CH2-), 34.48 (-CH2-), 34.46 (-CH2-), 34.36 (-CH2-), 33.73 (-CH2-), 33.58 (-CH2-), 33.43 (-CH2-), 29.80 (-CH2-), 29.73 (-CH2-), 29.35 (-CH2-), 27.28 (-CH2-), 27.23 (-CH2-), 27.20 (-CH2-), 27.03 (-CH2-), 26.97 (-CH2-), 26.92 (-CH2-), 26.26 (-CH2-), 26.18 (-CH2-), 26.17 (-CH2-), 26.10 (-CH2-), 1.05 (Pd-CH3).

[0073] Mass spectrometry: MALDI-TOF-MS (m / z): calcd for C 54 H 78 N2Pd: 860.5194, Found, 860.5211, [M-Cl-Me] + 。

[0074] Example 5:

[0075] 1. Application of Ni1 and Ni2 in catalytic ethylene polymerization

[0076] In the standard experimental procedure, a 350 mL thick-walled glass pressure vessel was dried in a hot air circulating oven at 60 °C for 2 h. After cooling to room temperature, 40 mL of cyclohexane and 200 equivalents of diethylaluminum chloride were injected into the vessel in a nitrogen-rich environment. 1 μmol of Ni(II) catalyst was dissolved in 1 mL of CH2Cl2 and injected into the polymerization system using a syringe. The reactor was pressurized to maintain a constant 6 atm of ethylene under vigorous stirring at 350 RPM. After 30 min, the reactor was depressurized and the resulting polymer was precipitated in ethanol. Subsequently, the polymer was filtered and then dried under vacuum conditions at 50 °C for at least 24 h.

[0077] 2. Application of Pd1 and Pd2 in catalytic ethylene polymerization

[0078] In a typical experiment, a 350 mL thick-walled glass pressure vessel was dried in a hot air circulating oven at 60 °C for 2 h. After cooling to room temperature, 40 ml CH2Cl2 and 2 equivalents of NaBArF were added to the vessel in a nitrogen atmosphere. 2 μmol of Pd(II) catalyst was added to 2 mL CH2Cl2 and injected into the polymerization system via a syringe. The reactor was pressurized and maintained at 6 atm of ethylene with rapid stirring (350 rpm). After 1 h, the pressure reactor was vented and the polymer was dried under reduced pressure using a rotary evaporator.

[0079] 3. Application of Pd1 and Pd2 in catalytic copolymerization of ethylene and methyl acrylate

[0080] In a typical experiment, a 350 mL thick-walled glass pressure vessel was dried in a hot air circulating oven at 60 °C for 2 h. After cooling to room temperature, 18 ml of CH2Cl2 and 2 equivalents of NaBArF and 20 or 40 mmol of methyl acrylate monomer were added to the vessel in a nitrogen atmosphere. 10 μmol of Pd(II) catalyst was added to 2 mL of CH2Cl2 and injected into the polymerization system via a syringe. The reactor was pressurized and maintained at 2 atm of ethylene with rapid stirring (350 rpm). After 12 h, the pressure reactor was vented and the polymer was dried under reduced pressure using a rotary evaporator.

[0081] The following table shows the experimental conditions for ethylene polymerization using the catalyst provided by the present invention; Complex, Temperature, Yield, Catalytic Activity b .), polymer molecular weight (M n c ), degree of branching (brs d) and other aggregated result data.

[0082]

[0083] a Polymerization conditions: catalyst 1 μmol, dichloromethane = 2 ml, [Al] / [Ni] = 200 equivalents, cyclohexane = 40 ml, ethylene pressure 6 atm, time = 30 min;

[0084] b The unit of activity is 10 6 g·mol -1 ·h -1 ;

[0085] c Polymer molecular weight M n and M w and molecular weight (M w / M n ) distribution was determined by GPC in trichlorobenzene at 150°C;

[0086] d The degree of branching refers to the number of branches per 1000 carbon atoms, which is 1 H NMR nuclear magnetic resonance determination;

[0087] e The melting points of polymers were determined by differential scanning calorimetry (DSC).

[0088]

[0089] a Polymerization conditions: catalyst 2 μmol, dichloromethane = 40 ml, NaBArF = 2 equivalents, ethylene pressure 6 atm, time = 60 min;

[0090] b The unit of activity is 10 5 g·mol -1 ·h -1 ;

[0091] c Polymer molecular weight M n and M w and molecular weight (M w / M n ) distribution was determined by GPC in THF at 40°C;

[0092] d The degree of branching refers to the number of branches per 1000 carbon atoms, which is 1 Determined by H NMR nuclear magnetic resonance method.

[0093]

[0094] a Polymerization conditions: catalyst 10 μmol, dichloromethane and MA = 40 ml, NaBArF = 2 equivalents, ethylene pressure 2 atm, time = 12 h, temperature 30 °C;

[0095] b The unit of activity is 10 3 g·mol -1 ·h -1 ;

[0096] c The MA insertion ratio is given by 1 H NMR nuclear magnetic resonance determination;

[0097] c Polymer molecular weight M n and M w and molecular weight (M w / M n ) distribution was determined by GPC in THF at 40°C;

[0098] d The degree of branching refers to the number of branches per 1000 carbon atoms, which is 1 Determined by H NMR nuclear magnetic resonance method.

[0099] The present invention describes in detail a ligand compound, a complex catalyst, a catalyst combination, and a method for preparing an olefin polymer. In order to more clearly demonstrate the principles and embodiments of the present invention, the present invention is described in detail through specific examples. However, it should be emphasized that the application of the present invention is not limited to the specific embodiments described in the present invention. Those skilled in the art should understand that various changes and modifications can be made to the present invention without departing from the core scope of the present invention. These improvements and modifications made based on the principles of the present invention also fall within the scope of protection of the claims of the present invention.

Claims

1. A fully flexible α-diimine catalyst, characterized in that Its general structure is shown below: ； R = cyclopentyl or cyclohexyl; M = Ni, X = Y = Br; alternatively, M = Pd, X = Cl, Y = Me.

2. The fully flexible α-diimine catalyst according to claim 1, characterized in that Its structure is as follows: 。 3. The method for preparing the fully flexible α-diimine catalyst according to claim 1, characterized in that The steps include: Step 1: Preparation of ligand A methanol solution containing tricycloalkyl aromatic amine is added to 1,2-cyclohexanedione, and acetic acid is added dropwise as a catalyst, and the mixture is stirred at room temperature for two days. After the reaction is completed, the precipitate is separated by filtration, washed with methanol, and vacuum dried to obtain ligand L1 or L2. Step 2: Preparation of catalyst 2a. Under nitrogen atmosphere, the ligand obtained in step 1 and an equimolar amount of (DME) NiBr2 are dissolved in dichloromethane, and the reaction is stirred at room temperature for 8-12 hours. After the reaction is completed, the solvent is partially evaporated, and the remaining mixture is diluted with anhydrous ether to precipitate an orange-red solid. The solid is separated by filtration, washed with ether and dried in vacuo to obtain the target product Ni1 or Ni2 compound. 2b. Under nitrogen atmosphere, the ligand obtained in step 1 and an equimolar amount of (COD) PdMeCl were dissolved in dichloromethane and stirred at room temperature for 8-12 hours. After the reaction was completed, part of the solvent was removed and the remaining mixture was diluted with ether to obtain an orange-red solid precipitate. The solid was separated by filtration, washed with ether and dried in vacuo to obtain the target product Pd1 or Pd2 compound. The synthetic route is as follows: 。 4. The preparation method according to claim 3, characterized in that: In step 1, the molar ratio of 1,2-cyclohexanedione to tricycloalkyl aromatic amine is 1:2.0-2.

5.

5. Use of the fully flexible α-diimine catalyst according to claim 1 in catalyzing olefin polymerization.

6. The use according to claim 5, characterized in that: The olefin is ethylene.

7. The use according to claim 6, characterized in that: The polymerization reaction is carried out in a composite catalytic system formed by a catalyst and a co-catalyst, wherein the co-catalyst is Et2AlCl or NaBArF.

8. The use according to claim 7, characterized in that: In the process of catalytic ethylene homopolymerization: The catalyst is Ni1 or Ni2, and the co-catalyst is Et2AlCl; the molar ratio of the catalyst to the co-catalyst Et2AlCl is 1:200-1:1000, and the amount of the catalyst is 1-10 micromoles; the temperature of the ethylene polymerization reaction is controlled between 30°C and 90°C, the ethylene polymerization pressure is maintained at 6-30 atmospheres, 40mL-100mL cyclohexane is used as a solvent, and the reaction time lasts for 30-60 minutes.

9. The use according to claim 7, characterized in that: In the process of catalytic ethylene homopolymerization: The catalyst is Pd1 or Pd2, and the co-catalyst is NaBArF; the molar ratio of the catalyst to NaBArF is in the range of 1:1-1:3, and the amount of the catalyst is 2-10 micromoles; the temperature of the ethylene polymerization reaction is controlled between 30°C and 70°C, the ethylene pressure is maintained at 6-10 atmospheres, 40mL-100mL of dichloromethane is used as a solvent, and the reaction time lasts for 60-120 minutes.

10. The use according to claim 7, characterized in that: In the process of catalytic copolymerization of ethylene and acrylic ester monomers: The catalyst is Pd1 or Pd2, and the co-catalyst is NaBArF; the molar ratio of the catalyst to the co-catalyst NaBArF is in the range of 1:1-1:3, the amount of the catalyst is 10-20 micromoles, and the concentration of the acrylate monomer is 1-2 mol / L; the reaction temperature is controlled between 30-70°C, the ethylene pressure is maintained at 2-10 atmospheres, 20mL-100mL of dichloromethane is used as a solvent, and the reaction time lasts for 3-12 hours.

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